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Abatract A series of compositionally complex fluorite oxides (CCFOs) were prepared by ball milling the mixture of ZrO2, HfO2, Y2O3, La2O3, and Pr6O11 followed by conventional solid-state sintering. Both XRD and TG-DSC results demonstrated that single-phase (Zr0.2Hf0.2Pr0.2Y0.2La0.2)O2-δ was formed at 1400°C. Elements in bulk ceramic were uniformly distributed without evident accumulation according to SEM-EDS pictures. TEM results revealed that polycrystalline ceramic powder was assignable to cubic Fm-3m fluorite structure. The electrical conductivity (σ) was measured via EIS technology and activation energy (Ea) of CCFOs was calculated in Arrhenius plots. In the temperature range of 300-750°C, CCFOs preserved the same conduction mechanism and (Zr0.1667Hf0.1667Pr0.1667Y0.25La0.25)O2-δ possessed higher σ and lower Ea than other high entropy fluorite oxides which is related to the incorporation of Pr element or the connection of cation-Vo complex.

Three-dimensional (3D) network structure of metal–organic framework (MOF) can accommodate outstanding electrocatalysis performances, but always collapse during the conversion to active materials or applications process. How to maintain the 3D network when producing active species is of great importance for full application of MOF. Herein, a new MOF material, In[Co(CN)6] (In-Co PBA) nanocubes, are firstly synthesized. Through a controlled low-temperature deligandation process, the In-Co PBA nanocubes are transformed to a novel In2O3@In-Co PBA quasi-MOF nanocubes, which basically retain the 3D porous structure of PBA but with in situ generated In2O3 nanoparticles inside. When used as CO2RR electrocatalyst, such a novel cubic composite structure exhibits excellent performances with faradaic efficiency of 85% for formate at a potential of −0.96 V and with current density of 31.5 mA·cm−2 at −1.32 V, surpassing most of the reported indium-based catalysts. The excellent performance can be attributed to the special composite structure, which provides not only active sites by In2O3 nanoparticles to catalyze CO2RR, but also the 3D porous framework by quasi-MOF to accelerate gaseous exchange and electrolyte permeation and prevent the electrode choking. This work offers a new strategy for the design of post-transition metal catalysts and the structure design of quasi-MOF.

Flexible fluorinated multi-walled carbon nanotube/polyarylene ether nitrile porous metacomposite film (FMWCNT/PEN) with negative permittivity has been fabricated via a delayed phase inversion method with a low content of FMWCNT.

Novel high-entropy perovskite-type (Ca0.2Sr0.2Ba0.2La0.2Pb0.2)TiO3 (CSBLP) ceramics with cubic structure of Pm-3m space group were successful prepared by solid-state reaction method. Results of XRD, SEM-EDS, HRTEM confirmed a homogeneous distribution and equimolar arrangement of multicomponent cations on the A-site. The high-entropy CSBLP ceramics showed long-range structural order and short-range chemical disorder with widely dispersed nanoscale grains varying sizes of 4-6 nm in the microstructure. Because of increased configurational entropy, the CSBLP ceramic has an enhanced Seebeck coefficient ( | S | = 272 μV/K at 1073 K) and low thermal conductivity (κ=1.75 W/m•K at 1073 K) when annealed at 1300 °C. This work demonstrates the possibility of effectively reducing thermal conductivity and improving the performance of thermoelectric oxides through high-entropy composition design.

Detecting circularly polarized light (CPL) signals is the key technique in many advanced sensing technologies. Over recent decades, many efforts have been devoted to both the material design and the device engineering of CPL photodetectors. CPL detectors with different sensing wavelengths have distinct applications in bio-imaging, drug discovery, and information encryption. In this review, we first introduce the working principle of state-of-the-art CPL photodetectors followed by a general material design strategy. We then systematically summarize the recent progress on the chiral materials developed for CPL detection, including inorganic metamaterials, organics, hybridized materials, etc. We compare and analyse the photocurrent dissymmetry factors of these systems and provide perspectives on strategies to improve the dissymmetry factors and extend the detection wavelength. We believe that the information we include in this review would attract broader interest from researchers working on different aspects of organic and hybridized semiconductor materials and devices.

Reversible luminescence modulation behavior upon the photochromic effect endows the photochromic ceramics with great potential in anti-counterfeiting and data storage applications. Here, Sm3+-doped KSr2Nb5O15 photochromic ceramics exhibit superior anti-counterfeiting ability: good covertness and considerable modulation ratio of luminescent emission intensity after photochromic reaction. The results show that the photochromism originated from oxygen and cation vacancies, which were directly identified by electron paramagnetic resonance and positron annihilation lifetime spectra. Unexpectedly, oxygen vacancies work more effectively than cation vacancies during photochromic reactions. Moreover, the extraordinary anti-counterfeiting ability was attributed to the high energy transfer rate, which was particularly caused by the short mean distance below 1 nm between the Sm3+ and vacancies. The work here has provided atomic-scale structural evidence and made a progress in understanding the photochromic origins and mechanism in color-center theory.

As a pH-sensitive nanomaterial, Eudragit S100 has good colon targeting. However, little research has been carried out on its mesoscopic scale. In this paper, the self-assembly behavior of Pulsatilla saponins D (PSD) and Eudragit S100, as well as the loading and release mechanism of PSD, was investigated via computer simulations. The effects of the self-assembly characteristics of PSD and Eudragit S100 in the dry powder state on the drug-carrier ratio were explored by the coarse-grained molecular dynamics (CGMD) method. According to the pH-responsive feature of Eudragit S100, the drug protection under gastric pH conditions and release in colonic pH conditions were simulated through the dissipative particle dynamics (DPD) method, which has provided insights into the microscopic morphological changes in the pH-sensitive drug delivery systems.

In the field of interface science, superwettability and photocatalysis are two significant research hot spots. Currently, wettability has been proved to be a decisive factor to enhance photocatalyt...

The power conversion efficiencies (PCEs) of laboratory-sized organic solar cells (OSCs), usually processed from low-boiling-point and toxic solvents, have reached high values of over 18%. However, there is usually a notable drop of the PCEs when green solvents are used, limiting practical development of OSCs. Herein, we obtain certificated PCEs over 17% in OSCs processed from a green solvent paraxylene (PX) by a guest-assisted assembly strategy, where a third component (guest) is employed to manipulate the molecular interaction of the binary blend. In addition, the high-boiling-point green solvent PX also enables us to deposit a uniform large-area module (36 cm2) with a high efficiency of over 14%. The strong molecular interaction between the host and guest molecules also enhances the operational stability of the devices. Our guest-assisted assembly strategy provides a unique approach to develop large-area and high-efficiency OSCs processed from green solvents, paving the way for industrial development of OSCs. Organic solar cells processed from green solvents are easier to implement in manufacturing yet their efficiency is low. Chen et al. devise a guest molecule to improve the molecular packing, enabling devices with over 17% efficiency.

Purpose For ball screw feed system, a sudden start or stop has a great influence on the transmission stiffness, so the axial stiffness mutation of feed system will occur. The purpose of this paper is to study the influence of acceleration on the transmission stiffness and dynamic characteristics of the ball screw feed system. Design/methodology/approach Taking the ball screw feed system as a research object, on the basis of the Hertz contact theory and the mixed element method, axial stiffness model and dynamic model are established. And the system stability was analyzed by the time history diagram and Phase-plane portrait diagram. The feed system was analyzed theoretically and experimentally, the experimental results are in good agreement with the model results. Findings Lead screw lead angle, preload, load and start acceleration affected ball-screw pair, bearing and transmission stiffness. And the load, nut contact stiffness, bearing contact stiffness, preload have a large effect on the transmission stiffness. The results show that a certain acceleration value will make the axial stiffness abrupt change. Originality/value This research provides a useful theoretical support for ensuring a good dynamic for the ball screw feed system.

Rapid and sensitive point-of-care testing (POCT) is an extremely critical mission in practical applications, especially for rigorous military medicine, home health care, and in the third world. Here, we report a visual POCT method for adenosine triphosphate (ATP) detection based on Taylor rising in the corner of quadratic geometries between two rod surfaces. We discuss the principle of Taylor rising, demonstrating that it is significantly influenced by contact angle, surface tension, and density of the sample, which are controlled by ATP-dependent rolling circle amplification (RCA). In the presence of ATP, RCA reaction effectively suppresses Taylor-rising behavior, due to the increased contact angle, density, and decreased surface tension. Without addition of ATP, untriggered RCA reaction is favorable for Taylor rising, resulting in a significant height. With this proposed method, visual sensitive detection of ATP without the aid of other instruments is realized with only a 5 μL droplet, which has good selectivity and a low detection limit (17 nM). Importantly, this visual method provides a promising POCT tool for user-friendly molecular diagnostics.

Dimensional optimization is important for planetary rovers to reach good performance, such as high mobility, stability, and low energy consumption. The paper presents a dimensional optimization for a planetary rover with rocker-bogie suspension. During the optimization process, the influence of dimensions on the actuation requirements is studied based on kinetostatics and terramechanics. The objective function is built considering the average driving torque requirements in the most common type of windblown terrain in Mars called megaripples. The optimal dimension design is reached through the genetic algorithm, and the influences of dimensional parameters on rover performances are studied by drawing performance atlases. This work realizes the consideration of energy consumption in the design phase of a planetary rover. Finally, the results guide the design of a rover prototype and are validated by a series of experiments.

Within the multi-barrier system for high-level waste disposal, the technological gap formed by combined buffer material block becomes the weak part of buffer layer. In this paper, Gaomiaozi bentonite buffer material with technological gap was studied, the heat transfer induced by liquid water flow and water vapor was embedded into the energy conservation equation. Based on the Barcelona basic model, the coupled thermo-hydro-mechanical model of unsaturated bentonite was established by analyzing the swelling process of bentonite block and the compression process of joint material. The China-Mock-up test was adopted to compare the numerical calculation results with the test results so as to verify the rationality of the proposed model. On this basis, the effect of joint self-healing on dry density, thermal conductivity and permeability coefficient of buffer material was further analyzed. The results show that, with bentonite hydrating and swelling, the joint material gradually increases in dry density, and exhibits comparatively uniform hydraulic and thermal conductivity properties as compacted bentonite block. As a result, the buffer material gradually shifts to homogenization due to the coordinated deformation.

Two-dimensional (2D) B2O monolayer is considered as a potential hydrogen storage material owing to its lower mass density and high surface-to-volume ratio. The binding between H2 molecules and B2O monolayer proceeds through physisorption and the interaction is very weak, it is important to improve it through appropriate materials design. In this work, based on density functional theory (DFT) calculations, we have investigated the hydrogen storage properties of Lithium (Li) functionalized B2O monolayer. The B2O monolayer decorated by Li atoms can effectively improve the hydrogen storage capacity. It is found that each Li atom on B2O monolayer can adsorb up to four H2 molecules with a desirable average adsorption energy (Eave) of 0.18 eV/H2. In the case of fully loaded, forming B32O16Li9H72 compound, the hydrogen storage density is up to 9.8 wt%. Additionally, ab initio molecular dynamics (AIMD) calculations results show that Li-decorated B2O monolayer has good reversible adsorption performance for H2 molecules. Furthermore, the Bader charge and density of states (DOS) analysis demonstrate H2 molecules are physically absorbed on the Li atoms via the electrostatic interactions. This study suggests that Li-decorated B2O monolayer can be a promising hydrogen storage material.

This communication presents a planar phased array designed with an enhanced reflection bandwidth, a wide-angle scan, and a broadband low backscattering. On one hand, an improved substrate integrated waveguide (SIW) cavity-backed slot antenna which supports dual resonant modes is designed and utilized as the array element. The dual-resonance element presents the advantages of wideband reflection, wide-beam radiation, and compact size, which has the benefit for the wideband wide-angle scan of the proposed phased array. On the other hand, a coding metasurface, which consists of four specially arranged unit cells, is presented and surrounds the slot array. Based on the specially designed coding metasurface, the array gain is enhanced and a broadband scattering reduction is realized. Both simulated and experimental results indicate that the designed phased array supports a main-beam scan up to 60° and a 3 dB beam coverage up to 75° in an active reflection band of 10.1–11.6 GHz. Besides, the results also show that the radar cross section (RCS) has the reduction from 6.2 to 16.3 GHz and from 6.2 to 15.2 GHz for TM and TE polarizations, respectively.

The luminescence modulation behaviour under the in-situ electric field of rare-earth doped KSr2Nb5O15 ceramics opened a new door for the development of dielectric materials. Where the understanding the effect of rare-earth doping on the electric properties of host, especially at the similar doping concentration with luminescence researches (low concentrations) is very important for the exploration of mechanism of electric-luminescent coupling effect. In this work, Nd3+-doped KSr2Nb5O15 (KSN-xNd) ceramics were synthesized, and the electric properties were investigated systematically. Our results suggest that the Nd3+ doping slightly increased the phase transition temperatures and improved the piezoelectric response of KSr2Nb5O15. Most importantly, a bidirectional dielectric tunability is revealed in KSr2Nb5O15. The dielectric permittivity can be adjusted by the DC electric bias, with tunability ranging from −12.3% to 21.9%. The related mechanism and relationship between the bidirectional dielectric tunability and ferroelectricity are revealed by temperature-dependent dielectric and ferroelectric characterization. The researches of electric properties and bidirectional dielectric tunability of KSN-based ceramics paved the way to further exploration of electric-luminescent coupling mechanism.

Because of the excellent static and fatigue performance, the interference-fit bolted structure has a wide application prospect in the joint field. In this paper, an improved spring-mass stiffness analytical prediction model is established for the interference-fit bolted single-lap laminated composite structure. The influences of interference-fit percentage, bolt preload, secondary bending and interface frictions are considered in the model. Combined with experimental research, the value of secondary bending moment coefficient ε is studied, and the correctness of the analytical model is verified. Based on the improved stiffness model, parametric research and regression analysis on the interference-fit percentage, preload, friction, laminate width and material properties are carried out and show that the overall structure stiffness is obviously affected by ε value, laminate width and laminates properties. The stiffness decreases with the increase of ε and increases with the increase of laminate width. And as the key factors, the interference-fit percentage mainly affects the joint local friction and bolt shear stiffness, the preload and friction coefficient mainly affect the local friction, and the laminates sizes and properties directly affect the overall structural stiffness.

It is imperative to develop methods for quantifying and imaging hypochlorous acid/hypochlorite (HOCl/ClO−) in living systems to clarify its roles in physiological and pathological processes and optimize therapeutic interventions for related diseases. Herein, we develop a ratiometric semiconducting polymer dot (Pdot)-based fluorescent probe with dual-emission at blue and green regions, PFO–PFPV Pdot, which is prepared from two fluorescent conjugated polymers including poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) and poly[(9,9-dioctyl-2,7-divinylene-fluorenylene)-alt-{2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene}] (PFPV), for detecting and imaging HOCl in living cells. The presence of HOCl can selectively oxidize PFPV components in Pdots and the oxidation reaction can be enhanced by UV irradiation, which interrupts the fluorescence resonance energy transfer (FRET) from PFO to PFPV and results in the fluorescence quenching of PFPV at green emission region and recovery of PFO at blue emission region. On the basis of the ratios of fluorescence intensities at PFPV and PFO as a function of HOCl concentrations, a ratiometric fluorimetry for HOCl detection with a low detection limit of 56.8 nM is proposed. Furthermore, the developed fluorescent probe is also used for ratiometric fluorescence imaging of exogenous and endogenous HOCl in RAW264.7 cells with satisfactory results. The developed PFO–PFPV Pdots show high specificity and sensitivity, low cytotoxicity, and good biocompatibility for HOCl detection.

Purpose Phenolic epoxy vinyl ester resin (PEVER) is an advanced resin matrix, which has excellent heat resistance, electrical insulation. However, the brittleness and poor toughness of its curing product limited its application, so this paper aims to modify the PEVER with hyperbranched polyimide (HBPI), so as to enhance the toughness, heat resistance and dielectric properties of PEVER. Design/methodology/approach Hexamethylene diisocyanate trimer was used as the central reactant. Methyl tetrahydrophthalic anhydride was used as the branching unit, stannous octoate was used as the catalyst and hydroquinone was prepared as the inhibitor. Then, the hyperbranched structure of HBPI was characterized by Fourier transform infrared spectrometer and 13C-NMR. Next, PEVER was mixed with different contents of HBPI, and then the authors tested its curing product. Findings It is found that with the addition of HBPI, the free volume of the system was increased and the content of polar groups was decreased in each unit space, so the dielectric constant (ε) and the dielectric loss (tanδ) were decreased. In addition, PEVER could be well toughened by HBPI and the thermal stability of PEVER was improved. Originality/value HBPI has excellent heat resistance. The addition of hyperbranched polymer increases the free volume of the system so it can slow down the transfer of stress and its nearly circular structure can absorb the impact energy from all directions. Moreover, an appropriate amount of free volume can decrease the dielectric constant of PEVER by reducing the content of polar groups.

New high-performance materials have attracted much attention due to ever-increasing demands for advanced communication technologies. In present work, Ge-doped Li3+xMg2Nb1-xGexO6 (0 ≤ x ≤ 0.08) ceramics are prepared via solid-state reaction route. Microstructural analysis and crystal structure refinement reveal that moderate substitution can promote grain growth and modify crystal structure, thus enhancing microwave dielectric properties of composites. In that sense, special attention is paid to the behavior of dielectric constant er, quality factor Q×f, and frequency temperature coefficient τf of final products. In these systems, er parameter depends on the density, miscellaneous phases, and polarizability; Q×f value is shown to be influenced by Nb-O bond energy, grain size, and bulk density; finally, τf characteristic refers to Nb-O bond valence and NbO6 octahedral distortion. Among above ceramics, Li3.02Mg2Nb0.98Ge0.02O6 composite sintered at 1250 °C exhibits outstanding microwave absorption performance with er = 15.32, Q×f = 969 88 GHz, and τf = −8.25 ppm/°C.

Sm3+ doped KSr2Nb5O15 (KSN-Sm) textured ceramics with anisotropic photochromic and luminescence modulation behaviors provided a new strategy for the enhancement of anti-counterfeiting ability. The KSN-Sm textured ceramics were fabricated by the tape casting technology, which exhibited obvious grain-orientation, with Lotgering factor f(00l) of 0.62. The textured sample possessed evident difference of reflectivity, photochromic, luminescent and luminescence modulation properties among various grain-orientated directions. The difference of luminescent emission intensity was over than 30 % and the luminescence modulation ratios △Rt are 75.3 % and 63.3 % along paralleled and vertical [00l] orientations, respectively. These optical anisotropies were attributed to the different refractive indexes, distributions of photochromic centers and energy transfer rates at various orientations. This work is hopeful to achieve the multidirectional data recording and enhancement of anti-counterfeiting ability of photochromic ceramics by the anisotropic properties of textured ceramics.

Liquid nitrogen (LN2) cooling can induce significant cracking damage in coalbed methane (CBM) reservoirs. To investigate the combined effects of LN2 cooling and bedding angles on the mechanical behaviors of bedded coal, coal specimens with different bedding angles (0°, 30°, 60° and 90°) were cooled. The variations in the surface features and P-wave velocity of the specimens were analyzed. The mechanical properties (tensile strength, peak strain and absorbed energy) were measured under Brazilian test conditions and compared. Furthermore, the crack propagation processes and the failure mechanisms were observed and compared. The results showed that LN2 cooling can induce considerable thermal damage inside the coal, resulting in the deterioration of the coal’s mechanical properties. This deterioration led to easier cracking and a higher fragmentation degree under splitting load. In addition, the reductions in tensile strength, peak strain and absorbed energy exhibited obvious anisotropic characteristics. The thermal cracks induced by LN2 cooling participated in the formation of macrocracks. After LN2 cooling, the failure mode remained unchanged from that before cooling at bedding angles of 0°, 30° and 90°. Notably, a transition from mixed-mode failure (primarily caused by tensile failure) to tensile failure occurred at the 60° bedding angle. This transition caused the specimen to fail at a relatively lower load, resulting in maximum reductions in tensile strength (34.8%), peak strain (27.6%) and absorbed energy (55.0%) at the 60° bedding angle. This paper provides new insights into the LN2 fracturing of bedded coal seams.

The binding mechanism of 7-ethyl-10-hydroxycamptothecin (SN38) with β-lactoglobulin (β-lg) was studied by molecular docking and molecular dynamics simulation. The docking results showed that van de...

The objective of this study is to examine the performance of the shallow reinforced concrete foundation of a large-scale wind turbine under the influence of environmental loads. A 2 MW horizontal-axis onshore wind turbine supported by a shallow concrete foundation was considered. The foundation stresses, foundation settlements, and static and dynamic contact pressures at various positions of the shallow foundation were monitored from the construction phase to the operation phase in the field. Numerical simulations were also performed to further analyze the behavior of the wind turbine foundation in different cases. The results demonstrate that the responses of the reinforced concrete foundation, i.e., foundation stresses, contact pressures, and foundation settlements, were variables closely related to the wind direction and wind speed. The distribution of foundation stresses suggested that a reasonable design of steel reinforcement cages around the foundation steel ring is important. The dynamic contact pressure of the foundation could reach 5 kPa, so the influence of dynamic wind loads on the foundation response could not be always neglected, particularly for the foundations seated on weak soils. The foundation settlement during the operation phase could be characterized by the logistic model, but its distribution was uneven due to the presence of eccentric upper weight and wind load. The findings would provide guidance for the foundation design of onshore wind turbines in hilly areas.

Although organic photovoltaics has made significant progress since its appearance decades ago, the underlying physics of charge transport in working cells is still under debate. Carrier mobility, determining the carrier extraction and recombination, is one of the most important but complex and still poorly understood parameters. Low-energy charge carrier states acting as traps play a particularly important role in carrier transport. Occupation of these states under real operation conditions of solar cells induces additional complexity. In this study, we use several transient methods and numerical modeling to address carrier transport under actual working conditions of bulk heterojunction organic solar cells based on fullerene and nonfullerene acceptors. We show that occupation of low-energy states strongly depends on the blend materials and the effective electric field. We define conditions when such occupation increases carrier mobility, making it less time-dependent on the microsecond time scale, and when its influence is only marginal. We also show that the initial mobility, determined by carrier relaxation within the high-energy part of the distributed density of states, strongly decreases with time independently of the low-energy state population. Funding Agencies|Vetenskapsradet, project "OPV2.0"; Carl Zeiss Foundation

A light-adjustable illumination scheme for hand-held probe for photoacoustic tomography is presented in this paper. The overall size of the probe is 120 × 60 × 40 mm3, which is easy to be held. Compared with traditional photoacoustic probe design, it has the following advantages: (1) Different excitation modes, that is, the different relative position between laser illumination area and ultrasonic detection area, can be selected as needed by tuning control parameters. (2) The spot-adjustable unit (SAU) specifically designed for beam expansion. (3) Angle Adjustment Unit (AAU) based on gear drive is proposed with single power input and bilateral output. Just by adjusting the motor parameters, the purpose of adjusting the incident angle can be precisely achieved. We built a PAT system based on our newly designed apparatus. Phantom and in vivo experimental results show that a variety of lighting schemes can be quickly generated according to requirements without changing the external settings, compared with the conventional probe.

The luminescence modulation behavior of lanthanide ion doped materials possesses great potential for applications in sensing, display and anti-counterfeiting devices. Unlike traditional tuning methods for chemical compositions, novel rare-earth doped ferroelectric oxides exhibit attractive luminescence modulation effects via electric polarization engineering, and enrich the development of multifunctional devices. In this work, Sm3+ doped KSr2Nb5O15 ceramics with abundant ferroelectric and luminescent properties were synthesized. The samples show different relaxation behaviors and ferroelectric features upon chemical and structural factors caused by Sm3+ doping, such as average ionic radii, local tolerance factors, and chemical bonds. After polarization at 20 kV/cm for 20 min, a considerable increase (~40%) in the luminescent emission intensity was obtained in 4 mol. % Sm3+ doped KSr2Nb5O15 ceramics. The related luminescence modulation mechanism was attributed to controlling the environmental symmetry around Sm3+ by the electric polarization.

Side-chain engineering is an effective strategy to regulate the solubility and packing behavior of organic materials. Recently, a unique strategy, so-called terminal side-chain (T-SC) engineering, has attracted much attention in the field of organic solar cells (OSCs), but there is a lack of deep understanding of the mechanism. Herein, a new noncovalently fused-ring electron acceptor (NFREA) containing two T-SCs (NoCA-5) was designed and synthesized. Introduction of T-SCs can enhance molecular rigidity and intermolecular π-π stacking, which is confirmed by the smaller Stokes shift value, lower reorganization free energy, and shorter π-π stacking distance in comparison to NoCA-1. Hence, the NoCA-5-based device exhibits a record power conversion efficiency (PCE) of 14.82 % in labs and a certified PCE of 14.5 %, resulting from a high electron mobility, a short charge-extraction time, a small Urbach energy (Eu ), and a favorable phase separation.

The non-fully conjugated polymer as a new class of acceptor materials has shown some advantages over its small molecular counterpart when used in photoactive layers for all-polymer solar cells (all-PSCs), despite a low power conversion efficiency (PCE) caused by its narrow absorption spectra. Herein, a novel non-fully conjugated polymer acceptor PFY-2TS with a low bandgap of ~1.40 eV was developed, via polymerizing a large π-fused small molecule acceptor (SMA) building block (namely YBO) with a non-conjugated thioalkyl linkage. Compared with its precursor YBO, PFY-2TS retains a similar low bandgap but a higher LUMO level. Moreover, compared with the structural analog of YBO-based fully conjugated polymer acceptor PFY-DTC, PFY-2TS shows a similar absorption spectrum and electron mobility, but significantly different molecular crystallinity and aggregation properties, which results in optimal blend morphology with a polymer donor PBDB-T and physical processes of the device in all-PSCs. As a result, PFY-2TS-based all-PSCs achieved a PCE of 12.31% with a small energy loss of 0.56 eV enabled by the reduced non-radiative energy loss (0.24 eV), which is better than that of 11.08% for the PFY-DTC-based ones. Our work clearly demonstrated that non-fully conjugated polymers as a new class of acceptor materials are very promising for the development of high-performance all-PSCs. [Figure not available: see fulltext.].

In this paper, based on the life cycle concept of oil sludge waste from the NdFeB manufacturing process, we investigate the process technology route to recover valuable elements from the oil sludge waste by hydro-metallurgical refining and calcium reduction to fabricate a sintered NdFeB magnet. The life cycle list was calculated and the environmental impact of the main processes was examined using the ReCiPe method, and the main factors of environmental impact were identified. The results showed that the hydrometallurgical technology route, compared with the calcium reduction technology route, resulted in 119.84% of human health hazards, 119.84% of ecological damage and 119.84% of resource. The consumption was found to be 13.08% higher than that of FDP. The sensitivity analysis revealed that the production of hydrochloric acid is highly sensitive to FDP, and power consumption is high to WTP in the hydrometallurgical technology route, and WTP in the calcium reduction unit process, and HTP in all processes in the calcium reduction technology route. The overall results show that reducing the environmental impact in the calcium reduction recovery process and accelerating the clean production of China's power resources are of great significance for the recovery of oil sludge waste for the preparation of recycled sintered NdFeB.

Amines are widely employed as additives for improving the performance of metal halide perovskite optoelectronic devices. However, amines are well-known for their high chemical reactivity, the impact of which has yet to receive enough attention from the perovskite light-emitting diode community. Here, by investigating an unusual positive aging effect of CH3NH3I/CsI/PbI2 precursor solutions as an example, we reveal that amines gradually undergo N-formylation in perovskite precursors over time. This reaction is initialized by hydrolysis of dimethylformamide in the acidic chemical environment. Further investigations suggest that the reaction products collectively impact perovskite crystallization and eventually lead to significantly enhanced external quantum efficiency values, increasing from similar to 2% for fresh solutions to greater than or similar to 12% for aged ones. While this case study provides a positive aging effect, a negative aging effect is possible in other perovksite systems. Our findings pave the way for more reliable and reproducible device fabrication and call for further attention to underlying chemical reactions within the perovskite inks once amine additives are included. Funding Agencies|ERCEuropean Research Council (ERC)European Commission [717026]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [51472164, 62005126]; 1000 Talents Program for Young Scientists of China; Shenzhen Peacock Plan [KQTD2016053112042971]; Educational Commission of Guangdong Province [2015KGJHZ006]; Research Foundation-Flanders (FWO)FWO [12Y7221N]

Recent advances in organic solar cells based on non-fullerene acceptors (NFAs) come with reduced non-radiative voltage losses (ΔVnr). Here we show that, in contrast to the energy-gap-law dependence observed in conventional donor:fullerene blends, the ΔVnr values in state-of-the-art donor:NFA organic solar cells show no correlation with the energies of charge-transfer electronic states at donor:acceptor interfaces. By combining temperature-dependent electroluminescence experiments and dynamic vibronic simulations, we provide a unified description of ΔVnr for both fullerene- and NFA-based devices. We highlight the critical role that the thermal population of local exciton states plays in low-ΔVnr systems. An important finding is that the photoluminescence yield of the pristine materials defines the lower limit of ΔVnr. We also demonstrate that the reduction in ΔVnr (for example

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In this study, Zn2+-substituted Li2MgSiO4 ceramics (Li2(Mg1-xZnx)SiO4, x = 0.00, 0.05, 0.10, 0.15, and 0.20) were synthesized using a traditional solid-state method. A fixed amount of LiF sintering aid (1.5 wt%) was added to the ceramics for decreasing the sintering temperature and adjusting their microwave dielectric properties. X-ray diffraction (XRD) results revealed no secondary phases, and scanning electron microscopy (SEM) data suggest that the Zn2+ ion substitution increased the size and uniformity of the grains, thereby affecting the densification of the prepared ceramics. The maximum bulk density (2.94 g/cm3) was found in a Zn2+ ion-substituted ceramic with x = 0.10 at a relative density of 94.2% (compared with the XRD theoretical density). Excellent microwave dielectric properties (er = 6.28, Q × f = 50400 GHz, and τf = −145 ppm/°C) can also be obtained at this zirconium content. We believe that the developed ceramics are promising for use as antenna substrates or transmit/receive modules in low-temperature co-firing ceramic applications.

A compact and robust in-fiber acoustically-induced Mach-Zehnder interferometer (AI-MZI) was demonstrated based on the phase mismatch in an acoustic wave driving fiber Bragg grating (FBG). The fiber structure of the AI-MZI was easy to fabricate and of a uniform diameter with larger refractive index difference in its arm part, which helped to reduce the length of the arm. In the experiment, the total length of the AI-MZI was less than 7 cm and the response time was about 120 $\mu$ s. The bandpass isolation and resonant center wavelength could be optimized by changing the power and frequency of the radio frequency source, respectively. As its application, a tunable and individually switchable dual-wavelength fiber ring laser was realized and characterized. The proposed structure gains advantages of robustness, easy fabrication, compact size and fast tuning speed accordingly. At the same time, it provides another practical way to use an FBG to introduce phase mismatch into an acousto-optic fiber grating.

Both surface and underground rocks in nature often undergo repeated drying and wetting. The dry-wet cycle is a weathering effect that includes physical and chemical processes, which has varying degrees of degradation effects on the physical and mechanical properties of rocks. This paper analyzes and discusses this kind of rock degradation based on the existing literature data. First, the deterioration degree of various physical and mechanical properties (including density, P-wave velocity, porosity, static and dynamic compressive/tensile strength, and fracture toughness) is summarized as the number of dry-wet cycles increases. Secondly, the possible degradation mechanism of the dry-wet cycle is explained in terms of clay mineral swelling, solute migration, and microcrack evolution. Then, the damage constitutive model of the rock after cyclic dry-wet treatment is introduced. Finally, the issues that need to be studied in the future are put forward.

Purpose Epoxy resin (EP) is a kind of thermosetting resin, and its application is usually limited by poor toughness. In this case, a type of new flexible chain blocking hyperbranched polyester (HBP) was designed and synthesized. The purpose of this study is to enhance the toughness and dielectric properties of EP. Design/methodology/approach P-toluene sulfonic acid was used as the catalyst, with dimethy propionic acid as the branch unit and pentaerythritol as the core in the experiment. Then, n-hexanoic acid and n-caprylic acid were, respectively, put to gain HBP with a n-hexanoic acid and n-caprylic acid capped structure. The microstructure, mechanical properties, insulation properties and dielectric properties of the composite were characterized for the purpose of finding the appropriate proportion of HBP. Findings HBP enhanced the toughness of epoxy-cured products by interpenetrating polymer network structure between the flexible chain of HBP and the EP molecular chain. Meanwhile, HBP reduced the ε and tgδ of the epoxy anhydride-cured product by reducing the number of polar groups per unit volume of the EP through free volumes. Research limitations/implications Yet EP is a kind of thermosetting resin, which is widely used in coating, aerospace, electronics, polymer composites and military fields, but it is usually limited by poor toughness. In a word, it is an urgent priority to develop new EP with better toughness and mechanical properties. Originality/value At present, HBP has been applied as a new kind of toughening strategy and as a modifier for EP. According to the toughening mechanism of HBP modified EP, the free volume of HBP creates a space for the EP molecule to move around when loaded. Moreover, the free volume could cause the dielectric constant of EP to diminish by reducing the content of polarizable groups. Meanwhile, the addition of HBP with flexible chains grafted to the EP could develop an interpenetrating network structure, thus further enhancing the toughness of EP

A novel oxygen reduction reaction (ORR) electrocatalyst silver@platinum-cobalt-rGO nanoflower (Ag@PtCo-rGO NFs) is prepared by hydrothermal reduction method. The formation of silver chloride likes elm leaf microstructure in the reaction process, performing as a template. The Ag@PtCo-rGO NFs exhibit excellent electrocatalytic activity, whose specific activity is 9 times higher than that of commercial Pt/C. More importantly, Ag@PtCo-rGO NFs demonstrate excellent durability than JM Pt/C for ORR in acid media, as evidenced by accelerated durability test after 40,000 cycles. These excellent performances can be attributed to the special structure, atomic steps and synergistic effect between Pt, Ag and Co. The density functional theory calculation shows that Ag@PtCo has the best activity, which is related to the transition state for O–O bond. This work proposes a promising pathway for the synthesis of surfactant-free nanoflowers structure catalysts with high catalytic performance and low cost.

For the study, we prepared a low grain boundary three-dimensional CH3NH3PbI3 crystal (3D-MAPbI3) on TiO2 nanoarrays by inhibition of ammonium iodide and discussed the formation mechanism of the crystal. Based on the 3D-MAPbI3 crystal, solar cells showed modified performance with a power conversion efficiency (PCE) of up to 19.3%, which increases by 36.8% in contrast to the counterparts. We studied the internal photocurrent conversion process. The highest external quantum efficiency is up to 92%, and the electron injection efficiency is remarkably facilitated where the injection time decreases by 37.8% compared to the control group. In addition, based on 3D-MAPbI3, solar cells showed excellent air stability, which possesses 78.3% of the initial PCE, even though they were exposed to air for 30 days. Our results demonstrate a promising approach for the fabrication of perovskite solar cells with high efficiency and stability.

Understanding defects is of paramount importance for the development of stable halide perovskite solar cells (PSCs). However, isolating their distinctive effects on device efficiency and stability is currently a challenge. We report that adding the organic molecule 3-phosphonopropionic acid (H3pp) to the halide perovskite results in unchanged overall optoelectronic performance while having a tremendous effect on device stability. We obtained PSCs with ∼21% efficiency that retain ∼100% of the initial efficiency after 1,000 h at the maximum power point under simulated AM1.5G illumination. The strong interaction between the perovskite and the H3pp molecule through two types of hydrogen bonds (HI and OH) leads to shallow point defect passivation that has a significant effect on device stability but not on the non-radiative recombination and device efficiency. We expect that our work will have important implications for the current understanding and advancement of operational PSCs., We thank the Spanish MINECO through the Severo Ochoa Centers of Excellence Program under grant no. SEV-2017-0706 for the postdoctoral contract to H.X. We thank the King Abdulaziz City for Science and Technology (KACST) for the financial support to M.G. and S.M.Z. A.H. is thankful for the financial support from the European Union H2020, ESPResSo project grant agreement 764047, and Swiss National Science Foundation project IZLCZ2_170177. Z.W. and S.F. are thankful for the “China Scholarship Council” fellowship (CSC). H.-S.K., M.G., and S.M.Z. are thankful for the financial support from the GRAPHENE Flagship Core 2 project supported by the European Commission H2020 Programme under contract 785219. P.T. and J.A. acknowledge funding from Generalitat de Catalunya 2017 SGR 327 and the Spanish MINECO project ANAPHASE (ENE2017-85087-C3). D.J.K. and L.E. acknowledge support from the Swiss National Science Foundation grant no. 200021_160112. S.T. acknowledges funding from the Computational Sciences for Energy Research tenure track programme of Shell, NWO, and FOM (project no. 15CST04-2), the Netherlands. S.D.S. and M.A. acknowledge funding from the Marie Skłodowska-Curie actions (grant agreement no. 841386) under the European Union’s Horizon 2020 research and innovation programme. S.D.S acknowledges support from the Royal Society and Tata Group (UF150033) and EPSRC (EP/R023980/1). X.S. and F.F. acknowledge the funding from the Swiss Federal Office of Energy (SFOE)-BFE (project no. SI/501805-01). K.G. appreciates support from the Polish Ministry of Science and Higher Education within the Mobilnosc Plus program (grant no. 1603/MOB/V/2017/0). K.J.T. acknowledges funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 804349 (ERC StG Cuhl) and RyC fellowship no. RYC-2017-22330. We give thanks to the Spanish State Research Agency for the grant Self-Power (PID2019-104272RB-C54 / AEI / 10.13039/501100011033) and the OrgEnergy Excelence Network (CTQ2016-81911-REDT), and to the Agència de Gestiód'Ajuts Universitaris i de Recerca (AGAUR) for the support to the consolidated Catalonia research group 2017 SGR 329 and the Xarxa d’R+D+I Energy for Society (XRE4S). Part of this work is under Materials Science Ph.D. Degree for A.M. and P.T. and the Chemistry Ph.D. programme for C.P. of the Universitat Autonoma de Barcelona (UAB, Spain). We thank CONACYT for the scholarship to C.P. We acknowledge Libertad Sole and also the Clean-Room from IMB-CNM for FIB process. ICN2 is supported by the Severo Ochoa program from Spanish MINECO (grant no. SEV-2017-0706) and is funded by the CERCA Programme/Generalitat de Catalunya.

Noncovalently fused-ring electron acceptors (NFREAs) have attracted much attention in recent years owing to their advantages of simple synthetic routes, high yields and low costs. However, the efficiencies of NFREAs based organic solar cells (OSCs) are still far behind those of fused-ring electron acceptors (FREAs). Herein, a series of NFREAs with S⋅⋅⋅O noncovalent intramolecular interactions were designed and synthesized with a two-step synthetic route. Upon introducing π-extended end-groups into the backbones, the electronic properties, charge transport, film morphology, and energy loss were precisely tuned by fine-tuning the degree of multi-fluorination. As a result, a record PCE of 14.53 % in labs and a certified PCE of 13.8 % for NFREAs based devices were obtained. This contribution demonstrated that combining the strategies of noncovalent conformational locks and π-extended end-group engineering is a simple and effective way to explore high-performance NFREAs.

In the operations of underground rock engineering, such as mining, the formation of goafs is often accompanied by unloading and energy effects. In this study, a cyclic loading and unloading stress test is carried out to analyze the strength characteristics of the loaded samples under different loading and unloading ranges as well as different numbers of cycles. The rock force is accompanied by substantial energy changes. To better fit the energy analysis under cyclic loading and unloading conditions, thermal infrared radiation characteristic analysis is performed during rock loading and unloading. An infrared radiation camera is adopted to detect the infrared characteristics of the rock force process after cyclic loading and unloading. Multiangle detection is implemented on the temperature, temperature field, and frequency histogram. The analysis shows that cyclic loading and unloading first strengthen and then weaken the rock. Moreover, the failure caused by the local stress concentration leads to a sharp increase in the temperature. There are significant temperature fluctuations before and after failure, and the temperature field after failure can be divided into three zones, namely, the normal temperature zone, heating zone, and mutational temperature zone, to comprehensively reflect that rock compression failure which is accompanied by the process of energy accumulation and release. On the basis of infrared energy analysis, the index of the energy release rate is introduced, and the loading and unloading analysis model is constructed. The research results reveal that rock failure is accompanied by the process of energy accumulation and release, which provides evidence for the analysis of the spatial stability of the rock mass under cyclic loading and unloading conditions and engineering excavation.

The electron backscatter electron diffraction (EBSD) technique was applied to study the microstructure evolution and properties of the annealed cold rolling C71500 cupronickel alloy tube. The fixed reduction ratio of C71500 alloy tube was 23.71%. After rolling with different thickness reduction, the change process of grain, the evolution of texture, the characteristic distribution of grain boundary and the mechanical properties of the alloy tube were discussed systematically. The texture of cold rolling tube was obviously different from the drawing and sheet textures, and only the textures of RZ{111 type and R-cube{001} type could be observed after the two roller cold rolling process. After a certain amount of deformation, obvious accumulated orientation differences could be seen in the textures, which could create favourable conditions for the recrystallization nucleation. In the rolling process, the nonuniformity deformation of tube was caused by the inconsistency of stress state. With the increase reduction of tube wall, the tensile strength of the alloy increased from 405.13 to 574.65 MPa, the yield strength increased from 310.35 to 338.76 MPa, and the micro-Vickers hardness increased from 137.40 to 186.01.

A series of rare earth zirconates (RE2Zr2O7) high-entropy ceramics with single- and dual-phase structure were prepared. Compared with La2Zr2O7 and Yb2Zr2O7, the smaller “rattling” ions (Yb3+, Er3+, Y3+) have been incorporated into pyrochlore lattice in (La0.2Nd0.2Y0.2Er0.2Yb0.2)2Zr2O7 (LNYEY) while larger ions (La3+, Nd3+, Sm3+, Eu3+) incorporated into fluorite lattice in (La0.2Nd0.2Sm0.2Gd0.2Yb0.2)2Zr2O7 (LNSGY). Due to high-entropy lattice distortion and resonant scattering derived from smaller ions Yb3+, Er3+, and Y3+, LNYEY shows a lower glass-like thermal conductivity (1.62-1.59 W m-1 K-1, 100-600℃) than LNSGY (1.74-1.75 W m-1 K-1, 100-600℃). Moreover, LNYEY and LNSGY exhibit enhanced Vickers’ hardness (LNYEY, Hv = 11.47 ± 0.41 GPa; LNSGY, Hv = 10.96 ± 0.26 GPa) and thermal expansion coefficients (LNYEY, 10.45 × 10-6 K-1, 1000℃; LNSGY, 11.02 × 10-6 K-1, 1000℃). These results indicate that dual-phase rare-earth-zirconate high-entropy ceramics could be desirable for thermal barrier coatings.