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This paper presents two-dimensional (2D) and three-dimensional (3D) numerical simulations of a half-scale geosynthetic reinforced soil (GRS) bridge abutment during construction and bridge load application. The backfill soil was characterized using a nonlinear elastoplastic model that incorporates a hyperbolic stress–strain relationship and the Mohr–Coulomb failure criterion. Geogrid reinforcements were characterized using linearly elastic elements with orthotropic behavior. Various interfaces were included to simulate the interaction between the abutment components. Results from the 2D and 3D simulations were compared with physical model test measurements from the longitudinal and transverse sections of a GRS bridge abutment. Facing displacements and bridge seat settlements for the 2D and 3D simulations agree well with measured values, with the 2D-simulated values larger than the 3D-simulated values due to boundary condition effects. Results from the 3D simulation are in reasonable agreement with measurements from the longitudinal and transverse sections. The 2D simulation can also reasonably capture the static response of GRS bridge abutments and is generally more conservative than the 3D simulation.

We constructed two-dimensional NiCo-metal–organic-framework (NiCo-MOF) nanosheets based on a facile protocol and then characterized them using multiple approaches (X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field emission-scanning electron microscopy (FE-SEM), and N2 adsorption/desorption isotherms techniques). As a sensitive electroactive material, the as-fabricated bimetallic NiCo-MOF nanosheets were employed to modify a screen-printed graphite electrode surface (NiCo-MOF/SPGE) for epinine electro-oxidation. According to the findings, there was a great improvement in the current responses of the epinine because of the appreciable electron transfer reaction and catalytic performance of the as-produced NiCo-MOF nanosheets. Differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry were utilized to analyze the electrochemical activity of the epinine on the NiCo-MOF/SPGE. A linear calibration plot was obtained in the broad concentration range (0.07–335.0 µM) with a high sensitivity (0.1173 µA/µM) and a commendable correlation coefficient (0.9997). The limit of detection (S/N = 3) was estimated at 0.02 µM for the epinine. According to findings from DPV, the electrochemical sensor of the NiCo-MOF/SPGE could co-detect epinine and venlafaxine. The repeatability, reproducibility and stability of the NiCo-metal–organic-framework-nanosheets-modified electrode were investigated, and the relative standard deviations obtained indicated that the NiCo-MOF/SPGE had superior repeatability, reproducibility and stability. The as-constructed sensor was successfully applicable in sensing the study analytes in real specimens.

A compact model able to predict the electrical read-out of field-effect biosensors based on two-dimensional (2D) semiconductors is introduced. It comprises the analytical description of the electrostatics including the charge density in the 2D semiconductor, the site-binding modeling of the barrier oxide surface charge, and the Stern layer plus an ion-permeable membrane, all coupled with the carrier transport inside the biosensor and solved by making use of the Donnan potential inside the ion-permeable membrane formed by charged macromolecules. This electrostatics and transport description account for the main surface-related physical and chemical processes that impact the biosensor electrical performance, including the transport along the low-dimensional channel in the diffusive regime, electrolyte screening, and the impact of biological charges. The model is implemented in Verilog-A and can be employed on standard circuit design tools. The theoretical predictions obtained with the model are validated against measurements of a MoS2 field-effect biosensor for streptavidin detection showing excellent agreement in all operation regimes and leading the way for the circuit-level simulation of biosensors based on 2D semiconductors., Spanish Government MCIN/AEI/10.13039/501100011033 through the projects PID2020-116518GB-I00 and TED2021-129769B-I00 (MCIU/AEI/FEDER-UE), FEDER/Junta de Andalucía-Consejería de Transformacion Económica, Industria, Conocimiento y Universidades through the projects P20_00633 and A-TIC-646-UGR20, PAIDI 2020 and the European Social Fund Operational Programme 2014–2020 no. 208, MCIN/AEI/PTA grant, with reference PTA2020- 018250-I, FPU program FPU019/05132, Plan Propio of Universidad de Granada

[EN] Magnetism and the existence of magnetic order in a material is determined by its dimensionality. In this regard, the recent emergence of magnetic layered van der Waals (vdW) materials provides a wide playground to explore the exotic magnetism arising in the two-dimensional (2D) limit. The magnetism of 2D flakes, especially antiferromagnetic ones, however, cannot be easily probed by conventional magnetometry techniques, being often replaced by indirect methods like Raman spectroscopy. Here, we make use of an alternative approach to provide direct magnetic evidence of few-layer vdW materials, including antiferromagnets. We take advantage of a surfactant-free, liquid-phase exfoliation (LPE) method to obtain thousands of few-layer FePS3 flakes that can be quenched in a solvent and measured in a conventional SQUID magnetometer. We show a direct magnetic evidence of the antiferromagnetic transition in FePS3 few-layer flakes, concomitant with a clear reduction of the Néel temperature with the flake thickness, in contrast with previous Raman reports. The quality of the LPE FePS3 flakes allows the study of electron transport down to cryogenic temperatures. The significant through-flake conductance is sensitive to the antiferromagnetic order transition. Besides, an additional rich spectra of electron transport excitations, including secondary magnetic transitions and potentially magnon-phonon hybrid states, appear at low temperatures. Finally, we show that the LPE is additionally a good starting point for the mass covalent functionalization of 2D magnetic materials with functional molecules. This technique is extensible to any vdW magnetic family., Funds from Ministerio de Ciencia e Innovación in Spain (RTI2018-096075-A-C22, RYC2019-028429-I). E.M.P. thanks the Spanish Ministerio de Ciencia e Innovación (PID2020-116661RB-I00) and Comunidad de Madrid (P2018/NMT-4367). M.G.H. and A.C.-G. acknowledge funds from European Union Horizon 2020 research and innovation program (Graphene Core3-Grant agreement no. 881603 Graphene-based disruptive technologies), EU FLAGACS ERA through the project To2Dox (JTC-2019-009), andComunidad de Madrid through the project CAIRO-CMproject (Y2020/NMT-6661). A.C.-G. also acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 755655, ERC-StG 2017 project 2D-TOPSENSE) and the Ministry of Science and Innovation (Spain) through the project PID2020-115566RB-I00. M.L.R.G. acknowledges support by the Spanish Ministry of Science and Innovation through Research Project PID 2020- 113753RB-100. The National Centre for Electron Microscopy (ELECMI National Singular Scientific Facility) is also acknowledge for provision of access to corrected aberration microscopy facilities. CzechNanoLab Research Infrastructure supported by MEYS CR (LM2018110) is acknowledged.

Magnetism and the existence of magnetic order in a material is determined by its dimensionality. In this regard, the recent emergence of magnetic layered van der Waals (vdW) materials provides a wide playground to explore the exotic magnetism arising in the two-dimensional (2D) limit. The magnetism of 2D flakes, especially antiferromagnetic ones, however, cannot be easily probed by conventional magnetometry techniques, being often replaced by indirect methods like Raman spectroscopy. Here, we make use of an alternative approach to provide direct magnetic evidence of few-layer vdW materials, including antiferromagnets. We take advantage of a surfactant-free, liquid-phase exfoliation (LPE) method to obtain thousands of few-layer FePS3 flakes that can be quenched in a solvent and measured in a conventional SQUID magnetometer. We show a direct magnetic evidence of the antiferromagnetic transition in FePS3 few-layer flakes, concomitant with a clear reduction of the Néel temperature with the flake thickness, in contrast with previous Raman reports. The quality of the LPE FePS3 flakes allows the study of electron transport down to cryogenic temperatures. The significant through-flake conductance is sensitive to the antiferromagnetic order transition. Besides, an additional rich spectra of electron transport excitations, including secondary magnetic transitions and potentially magnon-phonon hybrid states, appear at low temperatures. Finally, we show that the LPE is additionally a good starting point for the mass covalent functionalization of 2D magnetic materials with functional molecules. This technique is extensible to any vdW magnetic family, E.B. acknowledges funds from Ministerio de Ciencia e Innovación in Spain (RTI2018-096075-A-C22, RYC2019- 028429-I). E.M.P. thanks the Spanish Ministerio de Ciencia e Innovación (PID2020-116661RB-I00) and Comunidad de Madrid (P2018/NMT-4367). M.G.H. and A.C.-G. acknowledge funds from European Union Horizon 2020 research and innovation program (Graphene Core3-Grant agreement no. 881603 Graphene-based disruptive technologies), EU FLAGERA through the project To2Dox (JTC-2019-009), and Comunidad de Madrid through the project CAIRO-CM project (Y2020/NMT-6661). A.C.-G. also acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 755655, ERC-StG 2017 project 2D-TOPSENSE) and the Ministry of Science and Innovation (Spain) through the project PID2020-115566RB-I00. M.L.R.G. acknowledges support by the Spanish Ministry of Science and Innovation through Research Project PID 2020- 113753RB-100. The National Centre for Electron Microscopy (ELECMI National Singular Scientific Facility) is also acknowledge for provision of access to corrected aberration microscopy facilities. CzechNanoLab Research Infrastructure supported by MEYS CR (LM2018110) is acknowledged

The coupling energies between the buckled dimers of the Si(001) surface were determined through analysis of the anisotropic critical behavior of its order-disorder phase transition. Spot profiles in high-resolution low-energy electron diffraction as a function of temperature were analyzed within the framework of the anisotropic two-dimensional Ising model. The validity of this approach is justified by the large ratio of correlation lengths, $\xi_\parallel^+/\xi_\perp^+ = 5.2$ of the fluctuating $c(4 {\times} 2)$ domains above the critical temperature $T_\mathrm{c} = (190.6 \pm 10)$ K. We obtain effective couplings $J_\parallel = (-24.9 \pm 1.3)$ meV along the dimer rows and $J_\perp = (-0.8 \pm 0.1)$ meV across the dimer rows, i.e., antiferromagnetic-like coupling of the dimers with $c(4 {\times} 2)$ symmetry., Comment: Accepted for publication at Physical Review Letters on 02Feb23

Most machine learning methods assume that the input data distribution is the same in the training and testing phases. However, in practice, this stationarity is usually not met and the distribution of inputs differs, leading to unexpected performance of the learned model in deployment. The issue in which the training and test data inputs follow different probability distributions while the input–output relationship remains unchanged is referred to as covariate shift. In this paper, the performance of conventional machine learning models was experimentally evaluated in the presence of covariate shift. Furthermore, a region-based evaluation was performed by decomposing the domain of probability density function of the input data to assess the classifier’s performance per domain region. Distributional changes were simulated in a two-dimensional classification problem. Subsequently, a higher four-dimensional experiments were conducted. Based on the experimental analysis, the Random Forests algorithm is the most robust classifier in the two-dimensional case, showing the lowest degradation rate for accuracy and F1-score metrics, with a range between 0.1% and 2.08%. Moreover, the results reveal that in higher-dimensional experiments, the performance of the models is predominantly influenced by the complexity of the classification function, leading to degradation rates exceeding 25% in most cases. It is also concluded that the models exhibit high bias toward the region with high density in the input space domain of the training samples.

Two-dimensional (2D) liquid–metal (LM) heterointerfaces with their tunable physicochemical characteristics are emerging platforms for the development of multifunctional hybrid nanostructures with numerous functional applications. From this perspective, the functionalization of LM galinstan nanoparticles (NPs) with crystalline nanodomains is a promising approach toward the synthesis of novel 2D hybrid LM heterointerfaces with unprecedented properties. However, the decoration of LM heterointerfaces with desired nanocrystalline structures is a challenging process due to simultaneous and intensive interactions between liquid–metal-based structures and metallic nanodomains. The present study discloses a facile and functional method for the growth of crystalline nanodomains at LM heterointerfaces. In this sonochemical-assisted synthesis method, acoustic waves provide the driving force for the growth of ultra-fine crystalline nanodomains on the surface of galinstan NPs. The galinstan NPs were initially engulfed within carbon nanotube (CNT) frameworks, to prevent intensive reactions with surrounding environment. These CNT frameworks furthermore separate galinstan NPs from the other products of sonochemistry reactions. The following material characterization studies demonstrated the nucleation and growth of various types of polycrystalline structures, including Ag, Se, and Nb nanodomains on 2D heterointerfaces of galinstan NPs. The functionalized galinstan NPs showed tunable electronic and photonic characteristics originated from their 2D hybrid interfaces.

Funding Information: The authors acknowledge the German Research Foundation (DFG) by funding through projects SCHL 384/20-1 (Project No. 406129719), C05 (Project No. 278162697) within the SFB1242 “Non-Equilibrium Dynamics of Condensed Matter in the Time Domain,” and KR 4866/2-1. The authors also thank the HZDR Computing Center, HLRS, Stuttgart, Germany, and TU Dresden Cluster “Taurus” for generous grants of CPU time. Publisher Copyright: © 2023 American Physical Society. A key problem in ion-solid interaction is the lack of experimental access to the dynamics of the processes. While it is clear that the mechanisms of interaction and sputtering depend on the kinetic and potential energy (sum of ionization energies) of the projectile, the importance and interplay of the various interaction mechanisms are unknown. Here, we have irradiated substrate-supported (Au, SiO2) monolayers of MoS2 with highly charged xenon ions (HCIs; charge state: 17+ to 40+), extracted the emitted neutral postionized Mo particles in a time-of-flight mass spectrometer, and determined their velocity distributions. We find two main contributions, one at high velocities and a second at lower velocities, and assign them to kinetic and potential effects, respectively. We show that for slow HCIs (5 keV) the interaction mechanisms leading to particle emission by electronic excitation and momentum transfer, respectively, are independent of each other, which is consistent with our atomistic simulations. Our data suggest that the predominant mechanism for potential sputtering is related to electron-phonon coupling, while nonthermal processes do not play a significant role. We anticipate that our work will be a starting point for further experiments and simulations to better understand the interplay of processes arising from Epot and Ekin.

The electrochemical N2 reduction reaction (NRR) under ambient conditions is attractive in replacing the current Haber-Bosch process toward sustainable ammonia production. Metal-heteroatom-doped carbon-rich materials have emerged as the most promising NRR electrocatalysts. However, simultaneously boosting their NRR activity and selectivity remains a grand challenge, while the principle for precisely tailoring the active sites has been elusive. Herein, we report the first case of crystalline two-dimensional conjugated covalent organic frameworks (2D c-COFs) incorporated with M–N4–C centers as novel, defined, and effective catalysts, achieving simultaneously enhanced activity and selectivity of electrocatalytic NRR to ammonia. Such 2D c-COFs are synthesized based on metal-phthalocyanine (M = Fe, Co, Ni, Mn, Zn, and Cu) and pyrene units bonded by pyrazine linkages. Significantly, the 2D c-COFs with Fe–N4–C center exhibit higher ammonia yield rate (33.6 μg h–1 mgcat–1) and Faradaic efficiency (FE, 31.9%) at −0.1 V vs reversible hydrogen electrode than those with other M–N4–C centers, making them among the best NRR electrocatalysts (yield rate >30 μg h–1 mgcat–1 and FE > 30%). In situ X-ray absorption spectroscopy, Raman spectroelectrochemistry, and theoretical calculations unveil that Fe–N4–C centers act as catalytic sites. They show a unique electronic structure with localized electronic states at Fermi level, allowing for stronger interaction with N2 and thus faster N2 activation and NRR kinetics than other M–N4–C centers. Our work opens the possibility of developing metal–nitrogen-doped carbon-rich 2D c-COFs as superior NRR electrocatalyst and provides an atomic understanding of the NRR process on M–Nx–C based electrocatalysts for designing high-performance NRR catalysts.

The excellent intrinsic properties of two-dimensional MXenes, such as hydrophilic, good electrical and thermal conductivity, excellent film forming ability, render them potential candidates for many innovations in different areas. High-quality MXene plays an important role in enhancing the devices’ performances in various applications. However, the synthesis of high-quality MXenes has not been well documented. Herein, we summarize the up-to-date preparation strategies of MXene and compare their respective advantages and disadvantages. We particularly outline the criteria of high-quality MXenes, and focus on the influence of different synthetic methods on the surface functional groups, morphology (size and defect), layer spacing of MXene, etc. The challenges on MXenes’ preparation and their future perspectives are also provided. We anticipate this perspective will provide prospective guidance for synthesizing desirable high-quality MXenes.

Zinc manganese oxide (ZMO) system represents a notable family of mixed transition metal oxides (MTMOs) because of their superiority of the high theoretical capacity, adequacy of natural content, and low cost. However, the methods to match both the reliable synthesis and the designable construction of large-sized two-dimensional (2D) ZMO nanosheets are still considered grand challenges. Herein, we have successfully realized the preparation of 2D ZMO nanosheets with large lateral sizes up to ∼20 μm by simple pyrolysis of 2D metal-organic framework (MOF) nanosheets precursor. The growth mechanism of 2D MOF is proposed to be based on the lamellar micelles formed by polyvinyl pyrrolidone (PVP). The obtained 2D and porous ZMO nanosheets exhibit high specific capacity as well as good rate capability. More importantly, the as-prepared ZMO electrode shows a remarkable capacity increment upon cycling (from 832 mAh g-1 at the 2nd cycle to 1418 mAh g-1 at the 700th cycle, at 1 A g-1). Through simple adjustment of the calcination temperature, the valence state of Mn species in the yielding ZMO samples can be fine-tuned. Through systematic investigation towards these ZMOs containing different Mn species, the extra specific capacity is revealed to be chiefly on account of the arising of the valence state of Mn upon the cycling process. Moreover, it is disclosed that the higher-valent Mn the pristine ZMO contains, the more additional capacity it gains upon cycling. We believe that this work will inspire more detailed analysis on the relationship between the valence state of Mn and extra capacity.

Background: Midline cerebral structures are essential for the normal morphogenesis and function of the fetal brain. However, the diagnosis of congenital anomalies of midline cerebral structures. The Aim of The Work: This study aimed to evaluate the role of 2D versus 4D ultrasound in the diagnosis of midline structures of the fetal brain at the second trimester of pregnancy. Patients and Methods: 200 pregnant women at the second trimester [18-22 weeks] were selected. They were clinically evaluated to check the female and fetal wellbeing. Then a screening of fetal brain midline strictures had been performed by two- and four-dimensional ultrasound, aiming to discover any anomalies of the fetal brain midline structure. Both scans were compared with the postnatal transcranial ultrasound. Results: The 2D ultrasound detected no abnormality in 194 out of 200 fetuses [97.0%], and 4 cases [2.0%] had mega-cisterna magna, and 2 cases [1.0%] had encephalomylocele, which were detected by the 4 D and confirmed by postnatal transcranial ultrasound. The 4 D US discovered 2 cases [1.0%] of Dandywalker malformation, which was confirmed by postnatal transcranial US. There was a complete agreement between prenatal 4D ultrasound and postnatal transcranial ultrasound. The prenatal 2D ultrasound had a sensitivity of 75.0%, specificity of 100.0%, PPV of 100.0%, NPV of 98.7% and overall accuracy of 99.0%. Otherwise, the prenatal 4D ultrasound was 100.0% sensitive and specific. Conclusion: 4D ultrasound showed superiority in the diagnosis and confirmation of the fetal brain midline structure’s abnormalities. Also, the prenatal 4D ultrasound was 100.0% sensitive as postnatal transcranial US.

Chemical vapor deposition (CVD) allows lateral edge epitaxy of transition metal dichalcogenide heterostructures. Critical for carrier and exciton transport is the material quality and the nature of the lateral heterojunction. Important details of the optical properties were inaccessible in as-grown heterostructure samples due to large inhomogeneous broadening of the optical transitions. Here we perform optical spectroscopy of CVD grown MoSe2-WSe2 lateral heterostructures, encapsulated in hBN. Photoluminescence (PL), reflectance contrast and Raman spectroscopy reveal optical transition linewidths similar to high quality exfoliated monolayers, while PL imaging experiments uncover the effective excitonic diffusion length of both materials. The typical extent of the covalently bonded MoSe2-WSe2 heterojunctions is 3 nm measured by scanning transmission electron microscopy (STEM). Tip-enhanced, sub-wavelength optical spectroscopy mapping shows the high quality of the heterojunction which acts as an excitonic diode resulting in unidirectional exciton transfer from WSe2 to MoSe2.

Although electrokinetic treatments for soil remediation and ground improvement have gradually undergone significant experimental development, one of the most important physical phenomena has received very little attention in recent years. Electroosmotic flow, especially in unsaturated conditions, has not been simulated in domains of more than one dimension. In the present work, a modification of the M4EKR code was used to study water movement in partially saturated soils under electrokinetic treatments. Two different configurations were studied: electrodes placed in electrolyte wells and electrodes directly inserted into the soil, and the treatment was started under unsaturated conditions for both. Due to the unrestricted availability of fluid in the first case, soil saturation is inevitable, but in the second case, only a spatial redistribution of water content can be observed. A detailed analysis of a variety of configurations involving several electrolyte wells showed that the number of electrodes, the distance between them and, above all, the ratio between the two magnitudes determines the efficiency of soil saturation and the energy consumed in the process., Aunque los tratamientos electrocinéticos para la recuperación y mejora de suelos han experimentado gradualmente un importante desarrollo experimental, uno de los fenómenos físicos más importantes ha recibido muy poca atención en los últimos años. El flujo electroosmótico, especialmente en condiciones no saturadas, no ha sido simulado en dominios de más de una dimensión. En el presente trabajo se ha utilizado una modificación del código M4EKR para estudiar el movimiento del agua en suelos parcialmente saturados bajo tratamientos electrocinéticos. Se estudiaron dos configuraciones diferentes: electrodos colocados en pozos electrolíticos y electrodos insertados directamente en el suelo, y el tratamiento se inició en condiciones no saturadas para ambos. Debido a la disponibilidad ilimitada de fluido en el primer caso, la saturación del suelo es inevitable, pero en el segundo sólo se observa una redistribución espacial del contenido de agua. Un análisis detallado de diversas configuraciones con varios pozos electrolíticos demostró que el número de electrodos, la distancia entre ellos y, sobre todo, la relación entre ambas magnitudes determinan la eficacia de la saturación del suelo y la energía consumida en el proceso.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The structural stability and toxic lead are known obstacles to the current photovoltaic application of perovskite solar cells (PSCs) with high power conversion efficiencies (PCEs). Herein, we perform a systematic study contrasting structural, energetic and optoelectronic properties of 3D and 2D perovskites by substituting metal and halide compositions, and estimating the maximum PCE of these systems. Our investigation was performed with ab initio density functional theory calculations as implemented in the VASP (Vienna ab initio simulation package) code. We investigate 3D MABX3 perovskites with a 2x2x2 supercell and 2D (BA)2(MA)B2X7 (B = Ge, Sn, Pb, X = Cl, Br, I) structures with two octahedral layers. The inclusion of the organic spacer molecules is observed to change the distortions inside the octahedra and weaken the Jahn-Teller effect, as the effective coordination number for the B atom goes from 3.67 NNN to 5.16 NNN (NNN, number of nearest neighbors) considering 3D and 2D GeI-based materials. The BA molecules also provide a greater distortion between octahedra, with angles between B-X-B atoms presenting values in average 5º smaller than the bulk materials, which is a important factor as these distortions are known to affect the electronic band gap. Contrasting the stability of 3D and 2D perovskites, we observed that the presence of organic spacers on the 2D structure increases the cation/anion charge separation, which produces stronger Coulomb interactions resulting in a better stability. Our PCE estimates resulted in 8 perovskite combinations with values over 27% considering both 3D and 2D structures with BX = GeI, SnBr, SnI and PbI. Moreover, the 2D perovskites reached maximum PCEs with a 3.5x narrower layer thickness than 3D perovskites, envisioning a substantial fabrication cost reduction. Furthermore, the PCE estimate for (BA)2(MA)Sn2I7 showed an excellent result of 32.40%, a higher value than its 3D analogous MASnI3 with 27.63% and also higher than the 29.90% value for MAPbI3. The obtained results reinforce the better stability of 2D PSCs and can suggest promising materials with high PCE and without the toxicity of Pb. A estabilidade estrutural e o chumbo tóxico são obstáculos conhecidos para a atual aplicação fotovoltaica de células solares com perovskita (do inglês, PSCs) de alta eficiência de conversão energética (do inglês, PCE). Aqui, fazemos um estudo sistemático ao comparar propriedades estruturais, energéticas e optoeletrônicas de perovskitas 3D e 2D ao trocar a composição de metais e haletos na estrutura, e estimando o máximo PCE desses sistemas. Nossa investigação foi realizada com cálculos ab initio baseados na teoria do funcional densidade (do inglês, DFT) como implementado pelo código VASP (Vienna ab initio simulation package). Investigamos as estruturas 3D MABX3 com uma supercélula 2x2x2 e as estruturas 2D (BA)2(MA)B2X7 com duas camadas de octaedros (B = Ge, Sn, Pb, X = Cl, Br, I). Nota-se que a inclusão das moléculas orgânicas separadoras muda as distorções internas aos octaedros e enfraquece os efeitos de Jahn-Teller, uma vez que os números de coordenação efetivos para o átomo central B vão de 3,67 NNN a 5,16 NNN (NNN, do inglês, número de vizinhos mais próximos) considerando os materiais 3D e 2D à base de GeI. As moléculas BA também produzem uma maior distorção entre octaedros, com ângulos entre os átomos B-X-B tendo valores 5º menores, em média, que os materiais bulk, o que é um resultado importante considerando que essas distorções afetam o band gap eletrônico. Ao contrastar a estabilidade das perovskitas 3D e 2D, observamos que a presença dos espaçadores orgânicos nas estruturas 2D aumenta a separação de cargas cátion/ânion, o que produz interações de Coulomb mais fortes e, consequentemente, uma melhor estabilidade. Nossas estimativas de PCE trouxeram 8 materiais de combinações BX com PCE acima de 27% considerando ambas estruturas 3D e 2D com BX = GeI, SnBr, SnI e PbI. Além disso, as perovskitas 2D atingiram um valor máximo com uma espessura cerca de 3,5x menor que dos materiais bulk, o que se relaciona a uma possível redução considerável de custos de fabricação. Também obtivemos uma excelente estimativa de PCE para (BA)2(MA)Sn2I7 com 32,40%, um valor maior que para seu análogo 3D MASnI3 com 27,63% e também maior que o valor de 29,90% para MAPbI3. Os resultados obtidos reforçam a melhor estabilidade de PSCs 2D e permitem sugerir materiais promissores com alto PCE e sem a toxicidade do Pb. Processo nº 131673/2020-3, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In this study, two-dimensional (2D) MXene material (Ti3C2Tx) was employed to investigate its potentials toward the Cr(VI) removal in aqueous system by batch experiments. Characterization techniques such as SEM-EDS, HRTEM, XRD, FI-TR and XPS were used to analyze the structure and interaction of Ti3C2Tx before and after Cr(VI) adsorption. The results indicated that the layered structure of Ti3C2Tx had unique surface functional properties and abundant active sites, such as –OH, Ti–O, C = O, which exhibited high adsorption capacity for Cr(VI) removal. The Cr(VI) adsorption capacity by Ti3C2Tx decreased with the increase of pH, and its maximum value can reach 169.8 mg/g at pH = 2.0. The adsorption kinetic was well-explained by a pseudo-second-order kinetic, indicating that chemical interaction played a dominant role in the adsorption of Cr(VI) on Ti3C2Tx. Meanwhile, the isotherm data was calculated to conform to the Freundlich isotherm model. Thermodynamic analysis indicated that the adsorption process of Cr(VI) on Ti3C2Tx was a spontaneous endothermic process. These experimental results revealed that Ti3C2Tx had tremendous potential in heavy metals adsorption from aqueous solutions. HIGHLIGHTS Novel Two-dimensional titanium carbide nanosheets (Ti3C2Tx MXene) were employed for Cr(VI) scavenging.; Ti3C2Tx MXene exhibited high adsorption ability for the Cr(VI) removal, namely 169.8 mg/g at pH = 2.0.; The adsorption of Cr(VI) on Ti3C2Tx MXene is a multilayer adsorption and spontaneous endothermic process.; The chemical interaction played a dominant role in the Cr(VI) removal by Ti3C2Tx MXene.

Fabricating hierarchical nanomaterials by self-assembly of rod-coil block copolymers attracts great interest. However, the key factors that affect the formation of the hierarchical nanomaterials have not been thoroughly researched. Herein, we have synthesized two diblock copolymers composed of poly(3-hexylthiophene) (P3HT) and polyethylene glycol (PEG). Through a heating, cooling, and aging process, a series of multilayered hierarchical micelles and fibers were prepared in alcoholic solutions. The transition from fibers to hierarchical micelles are strictly influenced by the strength of the π-π stacking interaction, the PEG chain length, and solvent. In isopropanol, the P3HT22-b-PEG43 could self-assemble into hierarchical micelles composed of several two-dimensional (2D) laminar layers, driven by the π-π stacking interaction and van der Waals force. The P3HT22-b-PEG43 could not self-assemble into well-defined nanostructures in methanol and ethanol, but could self-assemble into fibers in isobutanol. However, the P3HT22-b-PEG113 with a longer corona block only self-assembled into fibers in four alcoholic solutions, due to the increase in dissolving capacity and steric hindrance. The sizes and the size distributions of the nanostructures both increased with the increase in polymer concentration and the decrease in solvent polarity. This study shows a method to fabricate the hierarchical micelles.

Designing a heterostructure photoanode with an appropriate band alignment, a beneficial charge migration pathway, and an adequate interfacial coupling is crucial for photoelectrochemical (PEC) energy conversion. Herein, we fabricate a hetero-nanostructure photoanode with CdS nanorods (CdS NRs) and two-dimensional (2D) ZnIn2S4 nanosheets (ZIS NSs) via a two-step in situ growth method on FTO glass to acquire a sufficient interfacial contact between two semiconductors. Based on their electronic band structures, the CdS is designed to be firstly grown on FTO to act as a photoelectron transport layer and 2D ZIS is further fabricated on the CdS as a photohole accumulation layer to directly contact the electrolyte. Benefitting from the Type II band alignment between the CdS and ZIS, such a heterostructure significantly enhances the separation efficiency and prolongs the lifetime of photocarriers. More importantly, it ensures that photoholes accumulate on the 2D ZIS with a highly exposed surface area for an oxidation reaction at the surface-active sites, while the photoelectrons transfer to counter electrode for hydrogen evolution. The optimum CdS@ZIS heterostructure photoanode exhibits a superior PEC performance with a photocurrent of 4.19 mA/cm2 at 1.23 VRHE (two times that of the CdS and eight times that of ZIS) and an applied bias photo-to-current efficiency (ABPE) of 1.93% at 0.49 VRHE. This work can inspire the future design of heterostructure photoanodes for highly efficient solar energy conversion.

The aim of this project is to develop a code that is capable of solving numerically the parabolised Navier-Stokes equations that govern the flow dynamics within two-dimensional boundary layers. Using a self-similarity scaling on the streamfunction formulation and given appropriate upstream and inviscid outer flow boundary conditions, the code solves the boundary layer and computes its characteristic properties. To begin with, the two-dimensional boundary layer equations have been cast in the streamfunction formulation and a Falkner-Skan-type coordinate change has been applied to express them in similarity variables. Next, the resulting third order equation has been reduced to first order following a standard approach, and the system is discretized in space using finite differences. The code has been tested against benchmark solutions for validation. The Blasius solution, which develops on a flat plate at zero incidence, and the stagnation point laminar boundary layer solution have been satisfactorily reproduced. Some problems previously solved with the approximate integral method have been revisited using the code to check the accuracy of the former. The code has also been adapted to accept outer flow boundary conditions in the form of both closed-form mathematical expressions or discrete streamwise samplings of the inviscid outer streamwise velocity distribution. A simple turbulence model has also been coded to resolve turbulent as well as laminar boundary layers and a criterion for natural transition has also been implemented. Typical behavior of turbulent boundary layers, such as their tendency to resist separation better than laminar boundary layers, is duly predicted. Finally, inviscid flow solutions past airfoils obtained with the software Xfoil have been fed into the boundary layer code to compute friction drag and detect separation. Results agree well with the literature, which further validates the accuracy of the boundary layer code

BACKGROUND The benefits of laparoscopic approach for right colectomy have been well established. However, the technical difficulty to construct the intra-corporeal anastomosis is still cumbersome. AIM To analyze the results of 3D and 2D laparoscopic right colectomy and to compare it to the published series through a systematic review and meta-analysis. METHODS A retrospective study with propensity score matching analysis of patients undergoing laparoscopic right colectomy at Umbria2 Hospitals from January 2014 to March 2020 was performed. A systematic review was accomplished comparing 2D and 3D right colectomy. RESULTS In the personal series 47 patients of the 2D group were matched to 47 patients of the 3D group. The 3D group showed a favorable trend in terms of mean operative time (170.7 ± 32.9 min vs 183.8 ± 35.4 min; P = 0.053) and a significant lower anastomotic time (16.9 ± 2.3 min vs 19.6 ± 2.9 min, P < 0.001). The complete mesocolic excision (CME) subgroups analysis showed a shorter anastomotic time (16.5 ± 1.8 min vs 19.9 ± 3.0 min; P < 0.001) and operative time (175.0 ± 38.5 min vs 193.7 ± 37.1 min; P = 0.063) in the 3D group. Six studies and our series were included in the meta-analysis with 551 patients (2D group: 291; 3D group: 260).The pooled analysis demonstrated a significant difference in favour of the 3D group regarding the operative time (P < 0.001) and the anastomotic time (P < 0.001) while no differences were identified between groups in terms of blood loss (P = 0.827), LNH yield (P = 0.243), time to first flatus (P = 0.333), postoperative complications (P = 0.718) and length of stay (P = 0.835). CONCLUSION The meta-analysis results showed that 3D laparoscopic right colectomy shortens operative and anastomotic time without affecting the standard lymphadenectomy. In our series, the advantage of the 3D system becomes evident when CME and/or more complex associated procedure are requested significantly reducing both the total operative and the anastomotic time.

Natural or synthetic graphite as precursors for the preparation of graphene oxide (GO) have constraints due to their limited availability, high reaction temperature for processing of synthetic graphite and higher generation cost. The use of oxidants, long reaction duration, the generation of toxic gases and residues of inorganic salts, the degree of hazard and low yield are some of the disadvantages of the oxidative-exfoliation methods. Under these circumstances, biomass waste usage as a precursor is a viable alternative. The conversion of biomass into GO by the pyrolysis method is ecofriendly with diverse applications, which partially overcomes the waste disposal problem encountered by the existing methods. In this study, graphene oxide (GO) is prepared from dry leaves of sugarcane plant through a two-step pyrolysis method using ferric (III) citrate as a catalyst, followed by treatment with conc. H2SO4. The synthesized GO is analyzed by UV-Vis., FTIR, XRD, SEM, TEM, EDS and Raman spectroscopy. The synthesized GO has many oxygen-containing functional groups (–OH, C–OH, COOH, C–O). It shows a sheet-like structure with a crystalline size of 10.08 nm. The GO has a graphitic structure due to the Raman shift of G (1339 cm−1) and D (1591 cm−1) bands. The prepared GO has multilayers due to the ratio of 0.92 between ID and IG. The weight ratios between carbon and oxygen are examined by SEM-EDS and TEM-EDS and found to be 3.35 and 38.11. This study reveals that the conversion of sugarcane dry leaves into the high-value-added material GO becomes realistic and feasible and thus reduces the production cost of GO.

River flooding has been triggering significant damage to lives and infrastructure and is a major worry all around the globe. To lessen these losses, proper planning and management methods need to be deployed. The purpose of this research is to fill a knowledge gap on the effects of reservoirs operation of the Idukki and Idamalyar to Periyar River Basin massive flooding. The proposed methodology is implemented on the Periyar River Basin located in Kerala, India, where severe flooding occurred during monsoon season in the year 2018. In this study, modelling technique has been used in two-step: (1) development of 1D physically based, distributed-parameter model (Soil and Water Assessment Tool, SWAT) to compute the stream flow and estimate the stream discharge at different outlet points; and (2) hybrid model is developed by linking SWAT with a well-known 2D hydrodynamic model (International River Interface Cooperative, iRIC) to display flood scenarios and to identify the flood-prone areas. The ArcSWAT user interface employed in the ArcGIS software was utilized to delineate the river basin. The SWAT model was calibrated and validated on daily and monthly basis at two gauge discharge stations, i.e., Neeleeswaram and Kalady. The statistical coefficients result obtained from SWAT model was in good agreement with the measured values for calibration and validation. The hybrid model simulation results compared with observed flood depth and remote sensing data demonstrated good capability of the model. Agreeable performances of computed results were observed in both flow fields and flood propagations. The result was compared with 2018 flood to check model accuracy and found to be satisfactory. The proposed framework can be utilized as an effective tool for efficient planning and management of natural disasters, such as flash floods.

Many previous studies of the occurrence of blocking anticyclones, their characteristics, and dynamics have defined the onset longitude using the one-dimensional zonal index type criterion proposed by Lejenas and Okland. In addition to examining the blocking event itself, the onset longitude was determined to start at the nearest five degrees longitude using the National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalyses that were used to identify the events. In this study, each blocking event in the University of Missouri Blocking Archive was re-examined to identify an onset latitude, and this information was added to the archive. The events were then plotted and displayed on a map of the Northern or Southern Hemisphere using Geographic Information System (GIS) software housed at the University of Missouri as different colored and sized dots according to block intensity and duration, respectively. This allowed for a comparison of blocking events in the archive above to studies that used a two-dimensional index. Then the common onset regions were divided by phase of the El Nino and Southern Oscillation (ENSO), and the typical onset of intense and persistent blocking events could be examined. The results found a favorable comparison between the onset regions identified here and those found in previous studies that used a two-dimensional blocking index. Additionally, there was variability identified in the onset regions of blocking in both hemispheres by ENSO phase, including the location of more intense and persistent events.

A feeding network crossing method is proposed to form an N $\times $ N dual-polarized two-dimensional multibeam antenna array (2D-MBAA) with analog-digital hybrid beamforming, which solves the problem of needing additional connection structure between the dual-polarized antenna array and analog feeding network for large-scale antenna arrays. The main design work is focused on the analog-beamformer (ABF) and two structures are proposed. One is vertical-crossed (VC) ABF and the other is parallel-crossed (PC) ABF, and the latter is a more complex design in exchange for a significantly reduced profile. As a verification, a $4\times 4$ dual-polarized 2D-MBAA with PC-ABF has been fabricated and tested. It is operated at 3.45GHz with a bandwidth of about 10%, and it can realize a scanning angle of ±45°.

We present a high-resolution non-contact method for the measurement of two-dimensional (2D) phosphor surface temperature distribution (PSTD) of phosphor-coated light-emitting diodes (pc-LEDs) based on advanced hyper-spectral imaging technology. The studied pc-LEDs with a surface-mounted device structure are mainly consisted of blue InGaN/GaN-based LED chips (with a spectral emission at about 456 nm), red (Sr,Ca)AlSiN3: Eu2+ phosphors (with a spectral emission at around 623 nm), and transparent silicone gels. Experimental temperature results are compared with those of micro-thermocouple ( $\mu $ -TC) and infrared thermal imaging (TI), and fairly good agreements can be noticed. However, the spatial resolution of this proposed method is more than one order of magnitude higher than that of TI method, and the proposed method provides more detailed surface temperature information of phosphors than the latter. Therefore, we believe that this proposed method can serve as useful tools for the non-contact measurement of PSTD in pc-LEDs with or without optics lens.

In the two-dimensional Cartesian coordinate system, a transient electromagnetic forward algorithm of the magnetic moment in arbitrary direction is developed to simulate the electromagnetic response characteristics of the whole space geoelectric model. The magnetic moment ${\mathbf {M}}_{r}$ in arbitrary transmitting direction is decomposed into ${\mathbf {M}}_{x}$ and ${\mathbf {M}}_{y}$ . The transient electromagnetic fields excited by the magnetic moments ${\mathbf {M}}_{x}$ and ${\mathbf {M}}_{y}$ are forwarded separately, and then synthesized to obtain the electric field excited by the magnetic moment ${\mathbf {M}}_{r}$ . The time domain iteration’s results of the uniform whole space are compared with the analytical solutions to verify the correctness of algorithm. The comparison results show that the algorithm is reliable and can be used for whole space transient electromagnetic simulation in an arbitrary direction. The forward response of the magnetic moment in an arbitrary transmitting direction removes the shortcomings of the traditional two-dimensional whole space transient electromagnetic simulations where the magnetic moment can only be in the horizontal or vertical direction. The program code can be used for the forward response of other two-dimensional whole space geological mining models. It is of great significance to study the two-dimensional transient electromagnetic diffusion characteristics of different geological models by the sector sweeping method.

In this article we show that the probability for an electron tunneling a rectangular potential barrier depends on its angle of incidence measured with respect to the normal line. The majority of the studies in the field consider a one-dimensional tunneling of an electron of mass in a potential barrier along the -axis. Using a two-dimensional approach, we observed that the angle of incidence of the electron influences the probability of tunneling. Neste trabalho mostramos que a probabilidade de um elétron tunelar em uma barreira de potencial retangular depende do seu ângulo de incidência medido em relação à linha normal. A maioria dos estudos na área considera um tunelamento unidimensional de um elétron de massa em uma barreira de potencial ao longo do eixo . Usando uma abordagem bidimensional, observamos que o ângulo de incidência do elétron influencia na probabilidade de tunelamento. &nbsp

The emergence and dominance of lithium-ion batteries in expanding markets such as consumer electronics, electric vehicles, and renewable energy storage are driving enormous interests and investments in the battery sector. The explosively growing demand is generating a huge number of spent lithium-ion batteries, thereby urging the development of cost-effective and environmentally sustainable recycling technologies to manage end-of-life batteries. Currently, the recycling of end-of-life batteries is still in its infancy, with many fundamental and technological hurdles to overcome. Here, the authors provide an overview of the current state of battery recycling by outlining and evaluating the incentives, key issues, and recycling strategies. The authors highlight a direct recycling strategy through discussion of its benefits, processes, and challenges. Perspectives on the future energy and environmental science of this important field is also discussed with respect to a new concept introduced as the Battery Identity Global Passport (BIGP).

Basic zeolites have shown great potential as efficient catalysts for biodiesel production in the transesterification reactions. However, conventional three-dimensional (3D) basic zeolites generally suffer from limited base sites and severe mass-transfer restriction, thereby suppressing their catalytic activity. Herein, 2D basic zeolites with large external surface areas, hierarchical characteristics, and abundant accessible and stable base sites are prepared by expansion, delamination and subsequent solid-state ion-exchange (SSIE) approach. The facile SSIE method provides more advantages in stabilizing and dispersing high concentration of strong basic sites than the conventional liquid-phase ion-exchange (LIE) approach. Due to the excellent mass transportation and stable basic sites, the 2D Na/ITQ-2 prepared by the SSIE approach shows remarkably enhanced activity and recyclability in the transesterification of triglycerides to produce biodiesel, compared to 3D zeolites and other reported basic zeolites. This work will open the boulevard to the rational design of 2D basic catalysts and expand the potential application of 2D zeolites to biodiesel production and other industrial reactions involving bulky molecules.

Purpose Consumer-grade virtual reality (VR) has recently enabled various medical applications, but more evidence supporting their validity is needed. We investigated the accuracy of simulated surgical planning in a VR environment (VR) with temporal bones and compared it to conventional cross-sectional image viewing in picture archiving and communication system (PACS) interface. Methods Five experienced otologic surgeons measured significant anatomic structures and fiducials on five fresh-frozen cadaveric temporal bones in VR and cross-sectional viewing. Primary image data were acquired by computed tomography. In total, 275 anatomical landmark measurements and 250 measurements of the distance between fiducials were obtained with both methods. Distance measurements between the fiducials were confirmed by physical measurement obtained by Vernier caliper. The experts evaluated the subjective validity of both methods on a 5-point Likert scale qualitative survey. Results A strong correlation based on intraclass coefficient was found between the methods on both the anatomical (r > 0.900) and fiducial measurements (r > 0.916). Two-tailed paired t-test and Bland–Altman plots demonstrated high equivalences between the VR and cross-sectional viewing with mean differences of 1.9% (p = 0.396) and 0.472 mm (p = 0.065) for anatomical and fiducial measurements, respectively. Gross measurement errors due to the misidentification of fiducials occurred more frequently in the cross-sectional viewing. The mean face and content validity rating for VR were significantly better compared to cross-sectional viewing (total mean score 4.11 vs 3.39, p Conclusion Our study supports good accuracy and reliability of VR environment for simulated surgical planning in temporal bones compared to conventional cross-sectional visualization.

15 figures, 2 tables., In this study, a 2D shallow water flow solver integrated with a water quality model is presented. The interaction between the main water quality constituents included is based on the Water Quality Analysis Simulation Program. Efficiency is achieved by computing with a combination of a Central Processing Unit (CPU) and a Graphics Processing Unit (GPU) device. This technique is intended to provide robust and accurate simulations with high computation speedups with respect to a single-core CPU in real events. The proposed numerical model is evaluated in cases that include the transport and reaction of water quality components over irregular bed topography and dry–wet fronts, verifying that the numerical solution in these situations conserves the required properties (C-property and positivity). The model can operate in any steady or unsteady form allowing an efficient assessment of the environmental impact of water flows. The field data from an unsteady river reach test case are used to show that the model is capable of predicting the measured temporal distribution of dissolved oxygen and water temperature, proving the robustness and computational efficiency of the model, even in the presence of noisy signals such as wind speed., This work was funded by the Spanish Ministry of Science and Innovation under the research project PGC2018-094341-B-I00. Additionally, Mario Morales-Hernández was partially supported by the U.S. Air Force Numerical Weather Modeling Program.

The purpose of this research was to find out the thinking processes of a concrete student in solving two-dimensional problems. The research method used is descriptive qualitative. The research subjects were two students taken using purposive sampling. The instrument used was the Test of Logical Operations and problem-solving tests. Stages of data analysis used are researching all data, making a cognitive classification of students, choosing concrete students to be used as research subjects, reviewing the results of concrete student work in solving mathematical problems, verify data and data sources that have been classified and transcribed in the presentation or exposure of data. The results showed that at the stage of understanding the problem and re-checking the answers, concrete students use the assimilation at the stage of planning to solve the problem of doing the disequilibration. At the stage of carrying out a plan to solve a problem, concrete students carry out the accommodation. During this study, it was found that students 'habits in mathematical problem-solving did not plan to solve problems, did not re-examine answers, and there were students' habits by interpreting the final results of problems. It can be concluded that the students' concrete thinking processes in solving two-dimensional problems vary according to the stages of problem-solving.

We evaluated the hot carrier generation in two-dimensional (2D) silver nanoparticle (AgNP) arrays under light illumination at different wavelengths, 458, 532, 671, and 785 nm. The 2D AgNP arrays were tailored to match the plasmon resonance to each excitation wavelength in order to fulfill the on-resonant condition. We selected para-aminothiophenol (p-ATP) as a probe molecule, which is chemically transformed into 4,4'-dimercaptoazobenzene (DMAB) upon light illumination. The reaction is driven by hot carriers emitted from a plasmonic surface. For evaluation of hot carrier generation, we monitored the chemical transformation from p-ATP into DMAB with surface-enhanced Raman scattering. The normalized Raman intensity of DMAB was plotted against the total exposure, where the peak intensity increased as the total exposure increased because of the increase of the number of DMAB molecules. The saturation of the peak growth was observed, indicating that the chemical transformation was completed, at different exposures for each wavelength. The total exposure required for completing the chemical transformation was smaller at 458 nm by at least ~105 times than that at 785 nm, although the difference of the photon energy was only 1.7 times. The growth of the Raman peak was related to the laser intensity as well, where the higher laser intensity showed a more rapid growth. These results indicated that more hot carriers with sufficient energy for the chemical transformation were generated at shorter excitation wavelengths as well as at higher laser intensities.

Band nesting occurs when conduction and valence bands are approximately equispaced over regions in the Brillouin zone. In two-dimensional materials, band nesting results in singularities of the joint density of states and thus in a strongly enhanced optical response at resonant frequencies. We exploit the high sensitivity of such resonances to small changes in the band structure to sensitively probe strain in semiconducting transition metal dichalcogenides (TMDs). We measure and calculate the polarization-resolved optical second harmonic generation (SHG) at the band nesting energies and present the first measurements of the energy-dependent nonlinear photoelastic effect in atomically thin TMDs (MoS2, MoSe2, WS2, and WSe2) combined with a theoretical analysis of the underlying processes. Experiment and theory are found to be in good qualitative agreement displaying a strong energy dependence of the SHG, which can be exploited to achieve exceptionally strong modulation of the SHG under strain. We attribute this sensitivity to a redistribution of the joint density of states for the optical response in the band nesting region. We predict that this exceptional strain sensitivity is a general property of all 2D materials with band nesting.

Introduction: Two-Dimensional ultrasound (2DUS) has been the preferred screening method for fetal abnormalities for several decades. Three-dimensional ultrasound (3DUS) is a technique that converts standard 2D grayscale ultrasound images into a volumetric dataset which allows visualization of the fetus in all three dimensions at the same time. It provides an improved overview and a more clearly defined demonstration of adjusted anatomical planes. The use of 3D imaging is however limited to being an adjunct to 2DUS in the visualization of fetal anomalies. The objective of this study is to highlight the importance of adding three-dimensional ultrasound (3DUS) to two-dimensional ultrasound (2DUS) during fetal anomaly screening. Methodology: This is a descriptive study conducted at a private fetal diagnostic center, in Nigeria between January 2014 and December 2016. The diagnosis of fetal anomalies was first made with 2DUS after which they were evaluated with 3D ultrasound images displayed on the monitor. Results: Nine fetuses with various fetal anomalies diagnosed on 2DUS were selected for further evaluation with 3DUS. These anomalies include a neck mass, lumbar spinal abnormality, bilateral cleft lip, thanatophoric dysplasia, anencephaly, omphalocele, posterior urethral valve with anhydramnios and ambiguous genitalia diagnosed. These anomalies were better demonstrated on 3DUS. Conclusion: 2DUS remains the mainstay imaging modality in screening for fetal anomalies. However, 3DUS may complement 2DUS by allowing better delineation of anomalies and gives the parents a better visualization and understanding of identified anomalies, thereby assisting in informed decision making.

Two-dimensional tin sulfide (SnS), as a black phosphorus-analogue binary semiconductor, has received considerable attention in photonics and optoelectronics. Herein, the third-order nonlinearity susceptibility Im χ3 is enhanced from −(6.88 ± 0.10) × 10−14 esu to −(15.90 ± 0.27) × 10−14 esu by the size-related quantum confinement in layered SnS nanosheets. Due to the energy level alignment, a phonon-bottleneck effect is observed, which leads to a prolonged carrier lifetime. These results provide a platform for actively tuning the linear and nonlinear optics, and pave the way for designing SnS-based tunable and anisotropic optoelectronic devices.

Although K+ is readily inserted into graphite, the volume expansion of graphite of up to 60% upon the formation of KC8, together with its slow diffusion kinetics, prevent graphite from being used as an anode for potassium-ion batteries (PIBs). Soft carbon with low crystallinity and an incompact carbon structure can overcome these shortcomings of graphite. Here, ultra-thin two-dimensional (2D) wrinkled soft carbon sheets (USCs) are demonstrated to have high specific capacity, excellent rate capability, and outstanding reversibility. The wrinkles themselves prevent the dense stacking of micron-sized sheets and provide sufficient space to accommodate the volume change of USCs during the insertion/extraction of K+. The ultra-thin property reduces strain during the formation of K-C compounds, and further maintains structural stability. The wrinkles and heteroatoms also introduce abundant edge defects that can provide more active sites and shorten the K+ migration distance, improving reaction kinetics. The optimized USC20−1 electrode exhibits a reversible capacity of 151 mAh g−1 even at 6400 mA g−1, and excellent cyclic stability up to 2500 cycles at 1000 mA g−1. Such comprehensive electrochemical performance will accelerate the adoption of PIBs in electrical energy applications.

The discrepancy between the bright theoretical projections for two-dimensional (2D) Janus structures and the lack of experimental realisation of these structures motivated us to study the effect of structural disorder on the stability of MoSSe, SnSSe, PtSSe, In2SSe and GaInSe2. The calculation results demonstrate that the difference between metal-sulfur and metal-selenium bonds makes Janus structures frustrated and less energetically favourable than less ordered allotropes of the same compounds. This result explains the difficulties encountered in experimental fabrication of these materials. In the bulk, there is an additional contribution to the total energy from dipole-dipole interactions between layers with a Janus structure that can overcome the energetic cost of structural frustration in layers for compounds with sufficiently large dipole moments. However, the entropic contribution to the free energy decreases the favourability of the ordered Janus structure. The calculation results are used to make recommendations to enable the discovery and synthesis of 2D materials with Janus structures., 11 pages, 3 figures, 3 tables, to appear in PCCP as Communication

En este artículo planteamos un análisis de la obra del artista Felice Varini desde un enfoque diferente a los numerosos textos críticos ya existentes. La originalidad de nuestro planteamiento consiste en el estudio que hacemos de la ilusión óptica que tiene lugar al observar sus piezas pictóricas expandidas en el espacio desde una posición estratégica y con un solo ojo. Es entonces cuando se produce, por un breve instante, la abolición del espacio tetradimensional, para dar lugar a una realidad bidimensional; lo cual enfatiza posteriormente la profundidad espacial, una vez que el observador queda desplazado respecto a dicha posición. A partir de la consulta de numerosas fuentes, además de una entrevista concedida por Varini, introducimos una clasificación técnica de sus diferentes tipologías de creaciones, siguiendo de un análisis crítico que contextualiza su obra en el panorama artístico contemporáneo. Nos detenemos en el análisis de la ilusión óptica que producen ciertas piezas del artista siguiendo diferentes estudios de psicología de la percepción que tratan sobre el reconocimiento de la profundidad espacial. Finalmente, establecemos una serie de conclusiones que confluyen en una triple paradoja que aporta una nueva interpretación de la obra de Varini en relación al espacio que habitamos., The aim of this article is the analysis of Felice Virani’s artworks from a different approach from the numerous existing critical texts. The uniqueness of this proposal involves a study on the optical illusion that takes place when observing Virani’s expanded paintings from a strategic position and with a single eye. It is then that the abolition of four-dimensional space occurs, for a brief moment, to give rise to a two-dimensional reality. Nevertheless, once the viewer is displaced from the projection point, spatial depth comes back again stronger than before. After consulting a large range of sources in addition to an interview given by Varini, we present a technical classification of his different creations, as well as a critical analysis that contextualizes his artworks in the contemporary art scene. We focus on the analysis of optical illusion produced by certain pieces of Varini based on studies of the psychology of perception about the recognition of spatial depth. Finally, we draw concrete conclusions that converge in a triple paradox which provides a new interpretation of Virani’s work concerning the space we inhabit.

Background: In dextro-transposition of the great arteries (dTGA), the aorta and the pulmonary artery are transposed. The present study aimed a three-dimensional speckle-tracking echocardiography-derived determination of volumetric and functional features of the atrium being on the morphologic right side [‘right atrium (RA)] in adult patients with dTGA. Methods: The present study comprised 18 adult dTGA patients, four of whom were excluded due to inferior image quality. From the remaining 14 patients (mean age: 29.7 ± 8.1 years, 9 males), 7 cases underwent Mustard-procedure, while another 7 subjects underwent Senning-procedure. Their results were compared to that of 28 age- and gender-matched healthy subjects (28.8 ± 1.4 years, 20 males). Results: Increased RA volumes respecting the cardiac cycle could be demonstrated in dTGA patients compared to controls. RA stroke volumes (SVs) for reservoir and conduit function were reduced together with impaired RA emptying fractions (EFs) featuring all phases of RA function. Mustard-operated patients showed tendentiously lower RA volumes and increased SVs and EFs respecting the cardiac cycle compared to those of Senning-operated patients suggesting beneficial results for Mustard-procedure. Reduced RA global and mean segmental peak RA strains and RA strains at atrial contraction could be detected in dTGA patients compared to those of controls with tendentiously lower values in Mustard-operated patients compared to those of Senning-operated subjects. Conclusions: Significant RA volumetric and functional abnormalities could be detected in adult dTGA patients following atrial switch repair. While RA volumetric data proved to be better in Mustard-operated patients, RA strains were enhanced in Senning-operated subjects.

This work systematically studied the structure, magnetic and electronic properties of the MXene materials Nd2N and Nd2NT2 (T = OH, O, S, F, Cl, and Br) via first-principles calculations based on density functional theory. Results showed that Nd2NT2 (T = OH, O, S, F, Cl, and Br) have half-metallic characteristics whose half-metallic band gap width is higher than 1.70 eV. Its working function ranges from 1.83 to 6.50 eV. The effects of strain on its magnetic and electronic structures were evaluated. Results showed that the structure of Nd2NT2 (T = OH, O, S, and Br) transitions from a ferromagnetic half-metallic semiconductor to a ferromagnetic metallic and ferromagnetic semiconductor under different strains. By contrast, the structures of Nd2NF2 and Nd2NS2 were observed to transition from a half-metallic semiconductor to a ferromagnetic metallic semiconductor under different strains. Calculations of the electronic properties of different proportions of the surface functional groups of Nd2NTx (T = OH, O, and F; x = 0.5, 1(I, II), and 1.5) revealed that Nd2NO1.5 has the characteristics of semiconductors, whereas Nd2NO(II) possesses the characteristics of half-metallic semiconductors. The other structures were observed to exhibit the characteristics of metallic semiconductors. Prediction of Nd2NT2 (T = OH, O, S, F, Cl, and Br) increases the types of lanthanide MXene materials. They are appropriate candidate materials for preparing spintronic devices.

Recently, the energy shortage has become increasingly prominent, and hydrogen (H2) energy has attracted extensive attention as a clean resource. Two-dimensional (2D) materials show excellent physical and chemical properties, which demonstrates considerable advantages in the application of photocatalysis compared with traditional materials. In this investigation, based on first-principles methods, 2D PtS2 and MoTe2 are selected to combine a heterostructure using van der Waals (vdW) forces, which suggests a type-II band structure to prevent the recombination of the photogenerated charges. Then, the calculated band edge positions reveal the decent ability to develop the redox reaction for water splitting at pH 0. Besides, the potential drop between the PtS2/MoTe2 vdW heterostructure interface also can separate the photogenerated electrons and holes induced by the charge density difference of the PtS2 and MoTe2 layers. Moreover, the fantastic optical performances of the PtS2/MoTe2 vdW heterostructure further explain the promising advanced usage for photocatalytic decomposition of water.

Triphenylene (TP) based materials have experienced a great expansion in the latest years. TP molecules have interesting optoelectronic properties, arising from the aromatic core, which have been exploited in functional two-dimensional (2D) Metal-Organic Frameworks (MOFs) and Covalent Organic Frameworks (COFs) aside other organic polymers. In this review we summarize synthetic approaches of TP-based 2D MOFs and COFs emphasizing on the resulting morphology, crystalline domains and orientation, proven to have great impact on the properties and performance of these materials in functional devices. Specifically, we report a detailed description on the different TP-based 2D structures detailing the influence of the chemical and crystalline structure on the electronic properties, specially the in-plane and out-of-plane contribution to the electrical conductivity. Finally, we give also attention and present several examples of functional devices made out with these electronic materials with great impact in the literature as well as in future technological applications., Coordination Chemistry Reviews, 460, ISSN:0010-8545

Рассмотрены возможности использования современной системы проектирования AutoCAD в учебном процессе. Описаны особенности интерактивных занятий по дисциплине «Инженерная и компьютерная графика», приведены примеры заданий, порядок их выполнения и преподавания. Показаны работы студентов в результате освоения учебной дисциплины., The possibilities of using the modern design system Auto CAD in the educational process are considered. The features of interactive lessons in the discipline «Engineering and computer graphics» are described, examples of tasks, the order of their implementation and teaching are given. The students works as a result of mastering the academic discipline is shown.

En este artículo planteamos un análisis de la obra del artista Felice Varini desde un enfoque diferente a los numerosos textos críticos ya existentes. La originalidad de nuestro planteamiento consiste en el estudio que hacemos de la ilusión óptica que tiene lugar al observar sus piezas pictóricas expandidas en el espacio desde una posición estratégica y con un solo ojo. Es entonces cuando se produce, por un breve instante, la abolición del espacio tetradimensional, para dar lugar a una realidad bidimensional; lo cual enfatiza posteriormente la profundidad espacial, una vez que el observador queda desplazado respecto a dicha posición. A partir de la consulta de numerosas fuentes, además de una entrevista concedida por Varini, introducimos una clasificación técnica de sus diferentes tipologías de creaciones, siguiendo de un análisis crítico que contextualiza su obra en el panorama artístico contemporáneo. Nos detenemos en el análisis de la ilusión óptica que producen ciertas piezas del artista siguiendo diferentes estudios de psicología de la percepción que tratan sobre el reconocimiento de la profundidad espacial. Finalmente, establecemos una serie de conclusiones que confluyen en una triple paradoja que aporta una nueva interpretación de la obra de Varini en relación al espacio que habitamos. The aim of this article is the analysis of Felice Virani’s artworks from a different approach from the numerous existing critical texts. The uniqueness of this proposal involves a study on the optical illusion that takes place when observing Virani’s expanded paintings from a strategic position and with a single eye. It is then that the abolition of four-dimensional space occurs, for a brief moment, to give rise to a two-dimensional reality. Nevertheless, once the viewer is displaced from the projection point, spatial depth comes back again stronger than before. After consulting a large range of sources in addition to an interview given by Varini, we present a technical classification of his different creations, as well as a critical analysis that contextualizes his artworks in the contemporary art scene. We focus on the analysis of optical illusion produced by certain pieces of Varini based on studies of the psychology of perception about the recognition of spatial depth. Finally, we draw concrete conclusions that converge in a triple paradox which provides a new interpretation of Virani’s work concerning the space we inhabit.

Ultrathin solar cells, with absorber layers less than one micron thick, have the potential to use orders of magnitude less high-quality semiconducting material than current silicon solar cells. This could be advantageous in applications that require high power output per unit weight, such as vehicle-integrated photovoltaics, or where reducing the capital cost of solar cell manufacturing is important. Transition metal dichalcogenides are a promising candidate for the semiconducting absorber layer of ultrathin solar cells due to their intrinsically passivated surfaces and their high absorption per unit thickness. This thesis explores two-dimensional transition metal dichalcogenides for ultrathin photovoltaics. We start with the simplest type of solar cell, which collects carriers via a Schottky junction formed by sandwiching the absorber layer between two metal contacts with different work functions. To enable this geometry and avoid Fermi-level pinning, we develop a new process for gently transferring van der Waals metal contacts onto transition metal dichalcogenides. We measure an open-circuit voltage of 250 mV and a power conversion efficiency of 0.5% in Schottky-junction solar cells. To improve upon this efficiency, we next make carrier-selective contact solar cells, which employ wide bandgap semiconductors to selectively collect electrons on one side and holes on the other side of the absorber layer. We measure an open-circuit voltage of 520 mV and a power conversion efficiency greater than 2% in devices based on perovskite solar cell geometries, with PTAA and C60 as selective contact layers. We demonstrate that short carrier lifetimes limit the voltage in these solar cells to 750 mV, well below the detailed balance voltage limit. This motivates a more thorough understanding of the carrier dynamics at play, and we use a new pump-probe optical microscopy technique, stroboSCAT, to spatiotemporally track heat and carrier evolution in transition metal dichalcogenides. When paired with a kinetic model, we show that this technique can be used to measure lifetimes and other important material parameters even in materials with low radiative efficiencies. We conclude by outlining future research directions towards achieving power conversion efficiencies greater than 10% in transition metal dichalcogenide solar cells.

International audience; Ag2Se has drawn widespread attention in wearable self-powered technologies because of its ductile nature, chemical stability, and low toxicity. However, its stable orthorhombic bulk phase is a narrow band gap material with compromised Seebeck coefficient. In this work, motivated by the discovery of stretchable Ag2Se and various studies demonstrating the positive role of halogenation toward semiconductor performance, synergistical enhancement of its Seebeck coefficient and quality factor integrating the weighted mobility and lattice thermal conductivity have been achieved by halogenation. Prediction of energy landscape within Ag2Se-X-2 (X = F, Cl, and Br) was calculated through global evolutionary algorithm in combination with first-principles approach. Three low-lying energy moieties, Ag2SeBr4, Ag2SeCl6, and Ag2SeF6, and their 2D counterparts with P1 symmetry are deformable inorganic semiconductors exhibiting sufficient electronic, thermal, mechanical and lattice stabilities. Ultimately, their combined low-lying dispersive phonon modes resulting from low crystal symmetry and flattened conduction band due to increased band gap drastically improve the Seebeck coefficient, reduce the band energy offset, and maintain the high phonon scattering rate, in turn leading to an ultralow thermal conductivity (< 0.50 W m(-1) K-1 at 300 K), enhanced bipolar conduction suppression, and large increase in electronic quality factor, without relinquishing the ductility. As a result, at and SIM;9 x 10(19) cm(-3) optimal carrier concentration, a broad plateaued figure of merit and SIM;1.1 starting from 400 K is obtained for p-doped Ag2SeBr4 and Ag2SeCl6 bulk materials, which corresponds to a 5-fold increase compared to Ag2Se and extends better thermoelectric behavior for Ag2Se over a wider temperature plateau. These structures display broader and steeper absorption coefficient alpha(omega) and SIM; 10(5) cm(-1) in contrast to Ag2Se, encompassing the visible to ultraviolet regions. in particular, all samples have spectroscopic limited maximum efficiency (SLME) above 20% at a scalable thickness of and GE;1.0 mu m. This work also shows that other interactions, namely Ag2Se-AgX and Ag2Se-X mixtures, are incorrect synthesis approaches.

Quantum materials are solids with tantalizing properties arising from special symmetry, dimensionality, topology, and many-body interactions between elementary degrees of freedom (charge, spin, orbital, and lattice). They are host to fascinating emergent phenomena such as unconventional superconductivity, Mott transitions, charge density waves (CDWs), and topologically-protected electronic states, and hold promise for revolutionizing electricity generation and distribution, (quantum) computing, and data storage. Gaining a microscopic understanding of quantum materials to experimentally realize and control many-body phases is one of the overarching goals of modern condensed-matter physics. A promising pathway to fulfilling this goal are ultrashort optical excitations. Tracking the response of a broken-symmetry state after perturbation by a light pulse grants access to the relevant many-body interactions governing the emergence of equilibrium quantum states. Additionally, the interaction of quantum materials with light can induce novel emergent phenomena by steering a system towards specific transient or metastable states, facilitating control over additional functionalities within the light-enriched phase diagram. This thesis explores the electronic structure and ultrafast dynamics of several single-layer and layered quasi-2D quantum materials using femtosecond time- and angle-resolved photoemission spectroscopy (trARPES). We first establish a novel time-of-flight-based photoelectron detector for trARPES, a momentum microscope, and benchmark its performance against the widely used hemispherical analyzers. Next, we utilize the complementary nature of both detectors to characterize the electronic nonequilibrium properties of a novel 2D topological insulator, bismuthene. We map the transiently occupied conduction band after photoexcitation, observe faint signatures of topological edge states within the large fundamental bulk band gap, and track the full relaxation pathway of hot photocarriers. Next, using trARPES in combination with a complementary time-resolved structural probe, we investigate the dynamics of a prototypical layered CDW compound, TbTe3, after optical excitation. Tracking the system's order parameter during the photoinduced CDW melting and recovery reveals a surprising reemergence of CDW order at elevated electronic temperatures far greater than the thermal critical temperature, which we attribute to strong nonequilibrium between coupled electronic and lattice degrees of freedom. Additionally, we show how changes of the CDW energy gap during the CDW-to-metal transition can lead to a transient modulation of the relaxation rates of excited high-energy photocarriers. Theoretical calculations based on a nonequilibrium Green's function formalism reveal the critical role of the phase space of electron-electron scattering and the interplay of elementary interactions and the electronic band structure. Lastly, we study the ultrafast nonthermal pathway to a long-lived metastable quantum state in bulk 1T-TaS2 after optical excitation. Utilizing a double-pulse excitation of a vibrational CDW coherence, we demonstrate a high degree of control over the phase transition, laying the basis for actively controlling macroscopic material properties on ultrafast timescales. The thesis concludes with an outlook on future research of quantum materials enabled by time-resolved momentum microscopy., Quantenmaterialien weisen emergente Phänomene mit faszinierenden Eigenschaften auf, wie beispielsweise unkonventionelle Supraleitung, Mott-Übergänge, Ladungsdichtewellen (CDWs) und topologisch geschützte elektronische Randzustände, welche zukunftsweisende Anwendungen in der Stromerzeugung und -verteilung, dem (Quanten-) Computing und der Datenspeicherung ermöglichen. Die außergewöhnlichen Eigenschaften von Quantenmaterialien resultieren aus einem komplexen Zusammenspiel von Symmetrie, Dimensionalität, Topologie, und Vielteilchen-Wechselwirkungen zwischen elementaren Freiheitsgraden (Ladung, Spin, Orbital und Gitter). Um emergente Phänomene zu realisieren und die makroskopischen Eigenschaften von Quantenmaterialien zu kontrollieren, ist jedoch ein mikroskopisches Verständnis dieses Zusammenspiels erforderlich. Einen vielversprechenden Ansatz hierzu bieten ultrakurze optische Anregungen. Die dynamische Antwort einer geordneten Phase auf eine optische Anregung ermöglicht Rückschlüsse auf fundamentale Wechselwirkungen. Darüber hinaus kann die Manipulation von Quantenmaterialien mit Licht neue Phänomene mit vielversprechenden Eigenschaften hervorrufen, indem Materialien gezielt in transiente oder metastabile Zustände überführt werden. Die vorliegende Arbeit untersucht die elektronische Struktur und ultraschnelle Dynamik verschiedener Quantenmaterialien mithilfe von zeit- und winkelaufgelöster Photoemissionsspektroskopie (trARPES). Zunächst etablieren wir einen neuartigen Photoelektronendetektor, das sogenannte Flugzeit-Impulsmikroskop, und vergleichen dessen Leistungsfähigkeit mit einem konventionellen Halbkugelanalysator im Rahmen üblicher trARPES Experimente. Anschließend nutzen wir die komplementäre Funktionsweise beider Detektoren um die elektronischen Eigenschaften des neuartigen 2D topologischen Isolators Bismuthen nach optischer Anregung zu charakterisieren. Wir bestimmen den Verlauf des Leitungsbands, beobachten Signaturen topologischer Randzustände innerhalb der Bandlücke und identifizieren den gesamten Relaxationspfad angeregter Elektronen. Daraufhin untersuchen wir mittels trARPES und komplementärer struktureller Messmethoden die Dynamik des quasi-2D CDW-Materials TbTe3 nach optischer Anregung. Der Verlauf des Ordnungsparameters während der photoinduzierten Unterdrückung und Rückkehr der CDW zeigt ein überraschendes Wiederauftreten der CDW-Ordnung bei elektronischen Temperaturen, die weit über der thermischen Übergangstemperatur liegen, was wir auf das Nicht-Gleichgewicht zwischen gekoppelten elektronischen und Gitter-Freiheitsgraden zurückführen. Zudem zeigen wir, wie sich das Schließen der elektronischen CDW-Bandlücke infolge des photoinduzierten Phasenübergangs auf die Relaxationsrate angeregter Elektronen auswirkt, was wir auf ein komplexes Wechselspiel zwischen Elektron-Elektron-Streuung und Bandstruktur zurückführen. Zuletzt untersuchen wir den photoinduzierten Übergang in eine langlebige metastabile Nicht-Gleichgewichtsphase in 1T-TaS2. Dabei nutzen wir eine Sequenz optischer Pulse zur Anregung einer CDW Kohärenz und erzielen ein hohes Maß an Kontrolle über die Stabilisierung der Nicht-Gleichgewichtsphase. Die Arbeit schließt ab mit einem Ausblick auf zukünftige Forschung an Quantenmaterialien mit einem Fokus auf zeitaufgelöste Impulsmikroskopie.