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Geometries, electronic structures, and magnetic properties for alkali earth metal atoms absorbed graphene have been studied by first-principle calculations. For Be and Mg atoms, the interactions between the adatom and graphene are weak van der Waals interactions. In comparison, Ca, Sr and Ba atoms adsorption on graphene exhibits strong ionic bonding with graphene. We found that these atoms bond to graphene at the hollow site with a significant binding energy and large electron transfer. It is intriguing that these adatoms may induce important changes in both the electronic and magnetic properties of graphene. Semimetal graphene becomes metallic and magnetic due to n-type doping. Detailed analysis shows that the s orbitals of these adatoms should be responsible for the arising of the magnetic moment. We believe that our results are suitable for experimental exploration and useful for graphene-based nanoelectronic and data storage. [ABSTRACT FROM AUTHOR]

To explore the effect of the introduction of heteroatoms on the properties of porphyrin materials, a new porphyrin-based derivative small-molecule donor named as PorTT-T was designed and synthesized based on alkyl-thieno[3,2-b]thiophene(TT)-substituted porphyrins. The linker bridge and end groups of PorTT-T were the same as those of XLP-II small-molecule donor materials, while the side-chain attached to the core of thieno[3,2-b]thiophene(TT)-substituted porphyrin was different. Measurements of intrinsic properties showed that PorTT-T has wide absorption and appropriate energy levels in the UV-visible range. A comparison of the morphologies of the two materials using atomic force microscopy showed that PorTT-T has a better surface morphology with a smaller root-mean-square roughness, and can present closer intermolecular stacking as compared to XLP-II. The device characterization results showed that PorTT-T with the introduced S atom has a higher open circuit voltage of 0.886 eV, a higher short circuit current of 12.03 mAcm−2, a fill factor of 0.499, a high photovoltaic conversion efficiency of 5.32%, better external quantum efficiency in the UV-visible range, and higher hole mobility. [ABSTRACT FROM AUTHOR]

Residual stresses are often imposed on the end-product due to mechanical and thermal loading during the machining process, influencing the distortion and fatigue life. This paper proposed an original semi-empirical method to predict the residual stress distribution along the depth direction. In the statistical model of the method, the bimodal Gaussian function was innovatively used to fit Inconel 718 alloy residual stress profiles obtained from the finite element model, achieving a great fit precision from 89.0% to 99.6%. The coefficients of the bimodal Gaussian function were regressed with cutting parameters by the random forest algorithm. The regression precision was controlled between 80% and 85% to prevent overfitting. Experiments, compromising cylindrical turning and residual stress measurements, were conducted to modify the finite element results. The finite element results were convincing after the experiment modification, ensuring the rationality of the statistical model. It turns out that predicted residual stresses are consistent with simulations and predicted data points are within the range of error bars. The max error of predicted surface residual stress (SRS) is 113.156 MPa, while the min error is 23.047 MPa. As for the maximum compressive residual stress (MCRS), the max error is 93.025 MPa, and the min error is 22.233 MPa. Considering the large residual stress value of Inconel 718, the predicted error is acceptable. According to the semi-empirical model, the influence of cutting parameters on the residual stress distribution was investigated. It shows that the cutting speed influences circumferential and axial MCRS, circumferential and axial depth of settling significantly, and thus has the most considerable influence on the residual stress distribution. Meanwhile, the depth of cut has the least impact because it only affects axial MCRS and axial depth of settling significantly. [ABSTRACT FROM AUTHOR]

Black phosphorene is a novel two-dimensional material which has unique properties and wide applications. Using first-principles calculations, we investigated the adsorption behavior of 12 different transition metals (TMs; Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au) on phosphorene. Our results showed that all of the adsorption systems have a large binding energy. The Fe-, Co-, and Au-phosphorene systems display magnetic states with magnetic moments of 2, 1, and 0.96 μB, respectively, which means that these systems are magnetic semiconductors. Adsorption of oxygen molecules on TM-phosphorene was also investigated. Interestingly, all the O2-(TM-phosphorene) systems, except O2-(Pd-phosphorene), can elongate the O-O bond, which is critical to their application as catalysts in the oxidation of CO. We also found that the adsorption of O2 molecules enables the O2-(Fe-, Ni-, Cu-, Ir-, Rh-, Ag-, and Au-phosphorene) systems to become magnetic semiconductors, and it allows O2-(Co-phosphorene) to display half-metallic state. Our results are expected to have important implications for phosphorene-based catalysis and spintronics. [ABSTRACT FROM AUTHOR]

The human teeth face a variety of ways to move during orthodontic treatment. The types of orthodontic tooth movements have linked to the moment to force (M/F) ratio. This paper aims to determine the precise M/F ratios that generate different types of movements for the models with and without bracket, and the M/F ratios are compared between the force systems applied in buccal-lingual and distal-mesial direction for the mandible canine by using finite element method (FEM). A segment of mandible canine obtained from autopsy had been scanned with microcomputed tomography, and two finite element models with and without brackets were established. Each canine model was subjected to a force of 100 cN and varied M/F ratios from 0 ~ 12 in buccal-lingual and distal-mesial directions. We find that the model with a bracket required larger M/F ratio compared to the model without a bracket for the same tooth movement. For the different directions, the value of M/F ratio is larger in the buccal-lingual than in the distal-mesial direction. The geometry of the tooth and the PDL are gained from a regular patient. Therefore, the results are applicable to any canine, and the precise M/F values provide a theoretical basis for the orthodontist design optimal force system. [ABSTRACT FROM AUTHOR]

In order to deeply investigate the tensile properties and fracture behaviors that are obtained by tensile tests of welded joints, constitutive and damage models are imperative for analyzing the tensile behaviors. In this work, the tensile tests are conducted on the T-welded joint specimens of aluminum alloy 6061-T6, which were cut from the T-welded joints of thin-walled parts under different welding currents of Tungsten Inert Gas Welding (TIGW). A modified Johnson-Cook (J-C) model based on the original J-C equation, Swift model, Voce model, and Hockett-Sherby (H-S) model, their linear combination model, and fracture failure model are constructed and applied to simulate tensile behaviors, combined with tensile test data. What is more, the finite element (FE) simulation of tension tests is executed with the VUMAT and VUSDFLD subroutines. Compared to those results simulated with different fracture criteria and tensile experiments, the tensile strength and yield strength of T-welded joint thin-walled parts under different welding currents were achieved, and their best mean errors were only about 1%. Furthermore, the accuracy of different fracture criteria is also evaluated by the correlation coefficient and mean squared error. The results show that the combination model can accurately predict the tensile properties and fracture behaviors of T-welded joints better than the single model, especially the results simulated with the Swift-H-S model and H-S-Voce model, which are in good agreement with tensile test results, which will provide an analysis foundation for enhancing the welding assembly quality and preventing fracture failure for complex thin-walled antenna structures. [ABSTRACT FROM AUTHOR]

This paper presents a gain-scheduling (GS) robust control strategy using the interpolation approach for ball screw drives while guaranteeing the system stability in the operating range. A set of linear-time-invariant (LTI) robust controllers is designed at selected table positions for the robustness against the uncertain load mass and the structural vibration suppression at those positions. By interpolating the LTI robust controllers, a GS robust controller is obtained to deal with the dynamic variations caused by the table motion. The closed-loop stability under the proposed GS robust controller is verified with the parameter-dependent Lyapunov function, which avoids tedious simulations to check the reliability of interpolating GS controllers before practical operations. The method presented in this paper enables the GS controller to consider the unmeasurable load mass in ball screw drives and simplifies the application complexity. The extensive experimental results demonstrate that the proposed GS robust controller significantly improves the tracking performance and the vibration suppression, in comparison to LTI controllers and GS controllers. • A gain-scheduling robust controller is developed for ball screw drives. • The table-position-dependent mode and the uncertain inertia are considered. • Parameter-dependent Lyapunov function is used to verify the closed-loop stability. • The proposed method improves the vibration suppression and trajectory tracking. [ABSTRACT FROM AUTHOR]

In recent years, RFID has become a viable solution to provide object's location information. However, the RFID-based positioning algorithms in the literature have disadvantages such as low accuracy, low output frequency and the lack of speed or attitude information. To overcome these problems, this paper proposes a RFID/in-vehicle sensors fusion strategy for vehicle positioning in completely GPS-denied environments such as tunnels. The low-cost in-vehicle sensors including electronic compass and wheel speed sensors are introduced to be fused with RFID. The strategy adopts a two-step approach, i.e., the calculation of the distances between the RFID tags and the reader, and then the global fusion estimation of vehicle position. First, a Least Square Support Vector Machine (LSSVM) algorithm is developed to obtain the distances. Further, a novel LSSVM Multiple Model (LMM) algorithm is designed to fuse the data obtained from RFID and in-vehicle sensors. Contrarily to other multiple model algorithms, the LMM is more suitable for current driving conditions because the model probabilities can be calculated according to the operating state of the vehicle by using the LSSVM decision model. Finally, the proposed strategy is evaluated through experiments. The results validate the feasibility and effectiveness of the proposed strategy. [ABSTRACT FROM AUTHOR]

Prediction of milling forces in peripheral milling of curved surface with variable curvature is complex. And the complexity arises due to the effects of cutter runout. This paper presents a method to predict milling force taking runout into account. Based on the concept of linear interpolation, methods are developed to calculate the instantaneous tool position, angular position, feed direction, and corresponding machining time. Then, a new analytical model of instantaneous uncut chip thickness is derived in the presence of cutter runout by coordinate transformation. In addition, the entry/exit angles are described considering the workpiece boundary. Milling tests are carried out to verify the presented method. A good agreement between predicted results and experimental results both in variation tendency and magnitude is achieved, which shows that the presented method is efficient. Meanwhile, comparative study with the existing method from literature is made. [ABSTRACT FROM AUTHOR]

• An abrasive grain is modeled with random and arbitrary pyramid which is defined by the relative position of five vertices. • The angle of abrasive grains and its area ratio play a dominant role in the establishment of the grinding wheel model. • High-precision characterization of the distribution, size and shape of abrasive grains is extracted through image processing techniques. • The simulated model agrees well with the experimental results regardless of abrasive grains' distribution, density or its size, count. A novel method for three-dimensional characterization and topography modeling of alumina abrasive grains and single crystal corundum grinding wheel trimmed by a diamond roller is proposed in this paper. An alumina abrasive grain is modeled with a random and arbitrary pyramid determined by the relative position of its five vertices. It is revealed that the relative position is related to the apex angle and volume ratio of abrasive particles. Considering the strong randomness of abrasive grain properties, high-precision characterization of the distribution, size and shape of abrasive grains is extracted through image processing techniques such as identification, segmentation, marking, and removal of connected domains. Meanwhile, a new set of parameters is defined to quantify the identified topographical features of abrasive grains on the wheel surface. It is illustrated that the angle of abrasive grains and its area ratio that can be extracted from dressing tests of the grinding wheel play a dominant role in the establishment of the grinding wheel model. Finally, three-dimensional topography model of the grinding wheel is built with the distribution, size and shape models of active abrasive grains and broken abrasive grains. The results show that the simulated topography model agrees well with the experimental measurements regardless of the distribution, area ratio, size, density or number of abrasive grains. [ABSTRACT FROM AUTHOR]

Recently, two-dimensional (2D) materials have attracted considerable focus because of their charming properties. Using 2D heterostructure as a photocatalyst for water splitting is a popular strategy for hydrogen production, which is a clean resource. In this work, the first-principle calculations were implemented to investigate the structural, electronic, interfacial and optical properties of 2D heterostructure based on ZnO and BSe. The heterostructure is formed by van der Waals (vdW) interaction and has a type-II band structure, which can separate the photogenerated electron–holes constantly. At the same time, the band alignment demonstrates the heterostructure has a decent band edge positions for the oxidation and reduction reactions of water splitting at pH 0. Besides, the ZnO/BSe vdW heterostructure possesses high carrier mobility of about 2538.16 cm2 V−1·s−1 along armchair direction. The charge difference and potential drop across the interface of the ZnO/BSe vdW heterostructure were addressed, which can induce a large built-in electric field, and this built-in electric field also is an important role to prevent the recombination of the photogenerated charges. Moreover, the ability of optical absorption of the heterostructure can be improved by the external biaxial strain. This study provides a new possible method to design the efficient photocatalysts for water splitting. Image 1 • Type-II band structure is addressed in ZnO/BSe vdW heterostructure. • The heterostructure has decent band edge positions for the redox reaction of water splitting. • The heterostructure possesses high carrier mobility and excellent optical absorption. [ABSTRACT FROM AUTHOR]

Based on first-principles calculations, we systematically investigate the electronic and optical properties of van der Waals (vdW) heterostructures composed of graphene-like gallium nitride (g-GaN) and transition metal dichalcogenides (TMDs). The investigated vdW heterostructures (g-GaN/MoS 2 , g-GaN/WS 2 , g-GaN/MoSe 2 , and g-GaN/WSe 2) are all semiconductors with direct bandgap. In particular, both the g-GaN/MoS 2 and g-GaN/WS 2 vdW heterostructures possess type-II band alignment, which will facilitate the separation of photogenerated carriers, and enhance their lifetime. Furthermore, band edge positions of these two heterostructures satisfied both water oxidation and reduction energy requirements, suggesting the potential in photocatalysts for water splitting. In addition, both g-GaN/MoS 2 and g-GaN/WS 2 vdW heterostructures exhibit a high electron mobility, which ensure that the redox reactions for water splitting will be effectively proceeded. More importantly, they show significant absorption peaks in the visible light region, leading to highly efficient utilization of the solar energy. These fascinating properties render the g-GaN/MoS 2 and g-GaN/WS 2 vdW heterostructures high-efficiency photocatalysts for water splitting. Unlabelled Image • Many g-GaN/TMD vdW heterostructures are direct-bandgap semiconductors. • Both g-GaN/MoS 2 and g-GaN/WS 2 form type-II heterostructure. • g-GaN/MoS 2 and g-GaN/WS 2 satisfy both water oxidation and reduction potential levels. • Both g-GaN/MoSe 2 and g-GaN/WSe 2 vdW heterostructures have type-I band alignment. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The most stable structures of the vertical heterostructures of MX 2 /BP (M =Mo, W; X =S, Se) are obtained. • Van der Waals interaction are found in these heterostructures. • Type-II band alignment are addressed in MoSe 2 /BP and WSe 2 /BP which can separate the photogenerated-charge. • All these heterostructures have excellent ability of optical absorption in the near-infrared and visible regions. Abstract Van der Waals (vdW) heterostructure can improve the performance of the 2D materials and provide more applications. Based on density functional theory (DFT) calculations, the properties of vertical heterostructures formed by transition metal dichalcogenides (TMDs) MX 2 (M = Mo, W; X = S, Se) and boron nitride (BP) were addressed. In particular, the vdW interaction exist in all these heterostructures instead of covalent bonding. The MoSe 2 /BP and WSe 2 /BP vdW heterostructures possess direct bandgap characterized by type-II band alignment and powerful built-in electric field across the interface, which can effectively separate the photogenerated-charge. Meanwhile, the MoS 2 /BP and WS 2 /BP vdW heterostructures also have the direct bandgap and intrinsic type-I band alignment. Furthermore, all heterostructures exhibit excellent optical absorption in the visible and near-infrared regions. Our investigation shows an effective method to design new vdW heterostructures based on TMDs and explores their applications for photocatalytic, photovoltaic, and optical devices. [ABSTRACT FROM AUTHOR]

Abstract Puckered arsenene is a new two-dimensional group V elemental material which has sparked much research interest owing to its fascinating properties and potential applications in various fields. To further widen its application, we studied arsenene doped with 10 different transition metals (TMs) by using first-principles calculations, focusing on the structural, electronic, and magnetic properties of TM-doped arsenene. Our calculation results show that all the substitutional systems have large binding energy, suggesting the formation of chemical bonds and consequently robust structural stability. The substitution of Ti, V, Cr, Mn, Fe and Ni atoms for As atoms induces a magnetic moment of 1, 2, 3, 4, 3, and 1 μ B in arsenene, respectively. Moreover, the V-, Mn- and Fe-doped systems exhibit half-metallic properties, while the Ti-, Cr-, and Ni-doped systems exhibit magnetic semiconductor properties. Adsorption of a single oxygen molecule on TM-doped arsenene was also investigated to determine whether O 2 can widen the application of substitutional arsenene systems for spintronic devices. The adsorption of a single oxygen molecule turns the Ti-, V-, Cr-, Mn-, Fe-, Co-, Ni-, and Pt-arsenene systems to magnetic metals which can be used as spin sources and drains in spintronic circuits. Interestingly, all the substitutional systems show good catalytic activity for CO oxidation since they can elongate the O O bond. In particular, after O 2 is adsorbed on the Sc-arsenene system, the O 2 molecule is almost decomposed, which provides much information on the requirements for a suitable CO oxidization catalyst with high activity and low cost. Our results are expected to lead to new opportunities for arsenene in spintronics and catalysts. Graphical abstract Image 109247 Highlights • Magnetic states appears in Ti, V, Cr, Mn, Fe, and Ni doped arsenene. • V, Mn, and Fe doped arsenene are half-metals. • Ti, Cr, and Ni doped arsenene are magnetic semiconductors. • The O 2 molecule is almost decomposed after adsorption on Sc doped arsenene. • Sc doped arsenene is very promising for CO catalysts. [ABSTRACT FROM AUTHOR]

Highlights • Thermal imaging technique can be used for the unwired and unobtrusive breathing rate measurement. • Influence of image resolution on BR measurement performance is researched. • Design of thermal imaging system in a specific application scenario should select the suitable image resolution. Abstract The aim of this work was to evaluate the influence of a thermal image resolution on the performance of thermal imaging system for remote and unobtrusive breathing rate (BR) measurement. The thermal imager with original resolution of 640 × 480 was first used to establish the thermal imaging system. The thermal video database containing 60 videos was developed to validate the feasibility of this system for BR measurement. Subsequently, the nearest-neighbor interpolation was exerted to create the thermal videos with low resolutions. The Bland-Altman plots of BR showed that distances between the upper and lower 95% limits of agreements were 4.094 bpm, 10.595 bpm, 10.091 bpm, 15.168 bpm and 20.769 bpm for video resolutions of 640 × 480, 512 × 384, 320 × 240, 192 × 144 and 64 × 48, respectively. With respect to linear regression analysis, the determination coefficient (R2) of 0.898, 0.890, 0.900, 0.776 and 0.539 had been found for the resolutions of 640 × 480, 512 × 384, 320 × 240, 192 × 144 and 64 × 48, respectively. These two statistical approaches both demonstrated that the thermal resolution of 320 × 240 achieved the performance comparable to the high thermal resolution. Inspired by the above results, for the practical applications, we can choose the appropriate resolution by taking both the system performance and cost into account. In this case, the thermal video resolution of 320 × 240 could be selected for BR measurement in some application scenarios (i.e. lie detection) where the measurement distance is approximately 1.5 m. This research may greatly improve the design of the contactless measurement device for physiological signals. [ABSTRACT FROM AUTHOR]

Using first-principles calculations, we systematically investigate the structures and electronic properties of fully hydrogenated and halogenated blue phosphorene (P 2 X 2 ). All these systems possess Dirac cone at high-symmetry K point, which are mainly contributed by P s p x p y orbitals. The Dirac cone in P 2 F 2 and P 2 I 2 systems lies exactly at the Fermi level. Formation energy analysis denotes that all the systems are energetically stable except P 2 I 2 . The mass density for P 2 H 2 and P 2 F 2 systems is rather small. Our calculations proposed that these systems, especially P 2 F 2 system, have great potential applications in future nanoelectronics. [ABSTRACT FROM AUTHOR]

Using first-principles calculations, we investigate the structural, electronic, and magnetic properties of 3d transition metal (TM) atoms substitutional doping of an arsenene monolayer. Based on the binding energy, the TM-substituted arsenene systems were found to be robust. Magnetic states were obtained for Ti, V, Cr, Mn and Fe doping. More importantly, a half-metallic state resulted from Ti and Mn doping, while the spin-polarized semiconducting state occurred with V, Cr and Fe doping. Our studies demonstrated the potential applications of TM-substituted arsenene for spintronics and magnetic storage devices. [ABSTRACT FROM AUTHOR]

• Type-II band structure is demonstrated in ZnO/GaN vdW heterostructure. • The heterostructure possesses decent band edge energy for the redox reaction of water splitting at pH 0 and 7. • High carrier mobility and excellent optical absorption are addressed by the heterostructure. In this work, based on density functional calculations, the structural, electronic, interfacial and optical performances of the two-dimensional van der Waals (vdW) heterostructure formed by ZnO and GaN are addressed. The heterostructure possesses a type-II band structure and decent band edge positions which can separate the photogenerated electron–holes pairs constantly for redox reaction of the water splitting at pH 0 and 7. The charge-density difference and potential drop across the interface of the heterostructure are investigated, which can result a built-in electric field to prevent the recombination of the photogenerated electron–holes. Besides, the high mobility of electrons about 3004.49 cm2·V−1·s−1 is found in the heterostructure along the transport direction. The heterostructure also has excellent optical absorption performance, which can be mediated by the external strain. This study offers guidelines for the design of vdW heterostructures used as photocatalysts for water splitting. [ABSTRACT FROM AUTHOR]

This study addresses critical challenges in the field of tissue engineering, specifically in the optimization of bioprinting technologies for the construction of complex, multicellular tissues. By utilizing a homemade piston-driven extrusion-based bioprinting (EBB) printhead, we performed detailed thermal and flow analyses to investigate the effects of temperature variations on the extrusion process of temperature-sensitive gelatin-alginate bioink. Through finite element method (FEM) simulations, we explored the temperature distribution within the printhead and its impact on bioink properties, such as viscosity, pressure, and shear stress. Key findings reveal significant temperature gradients from the printhead barrel to the nozzle tip, influencing bioink extrusion and filament morphology. This study further introduces an innovative hardware optimization with thermal insulators, designed to mitigate heat loss at the nozzle tip and ensure uniform temperature distribution. Both simulation and empirical printing experiments confirm the efficacy of thermal insulators in enhancing bioprinting fidelity and efficiency. This research contributes to the advancement of bioprinting technology by optimizing printhead design, with implications for improving the quality of bioprinted tissues and organs.

Aim: The present study aimed to develop a method for measuring 3D maxillary tooth movement during orthodontic treatment and to verify the accuracy of the method., Materials and Methods: A 3D model analysis method was established to measure tooth movement by combining the effects of CBCT and intraoral scans. Transformation matrices were used to abstract the motion features of the teeth and translate them into translations and rotations. To test the validity and reliability of the method for clinical application, the inclination of the central incisor was measured using a 3D model analysis method and cephalometric analysis. Measurement error, correlation, and agreement between the two methods were analyzed using the Dahlberg formula, intraclass correlation coefficient, and Bland-Altman analysis, respectively. The performance of the 3D model analysis method was evaluated by monitoring the canine movement of a patient who underwent a premolar extraction., Results: The measurement error was 0.58 degrees for the 3D model analysis and 2.02 degrees for the cephalometric analysis. There was no significant difference in the central incisor inclination measurements between the cephalometric and the 3D model analyses methods. A high correlation (0.974) and narrow limits of agreement (-3.55 degrees, 4.16 degrees) were obtained between the two methods. Minute movements and additional details of orthodontic tooth movements could be observed using the 3D model analysis method., Conclusion: The 3D model analysis method was reliable and reproducible for clinical application in monitoring the 3D maxillary tooth movement during orthodontic treatment. The trueness should be further evaluated. (Int J Comput Dent 2023;26(1): 49-0; doi: 10.3290/j.ijcd.b3818301).

To overcome current serious energy and environmental issues, photocatalytic water splitting holds great promise because it requires only solar energy as an energy input to produce hydrogen. In this work, based on first-principle calculations, we studied the van der Waals heterostructure formed by PtS 2 and arsenene (Are) monolayers that were successfully synthesized on a large scale at high quality. From an analysis of the migration paths of photoinduced electrons and holes, a direct Z-scheme photocatalytic mechanism is demonstrated in this heterostructure. Furthermore, the PtS 2 /Are direct Z-scheme heterostructure has decent band edge positions to promote the redox reaction to decompose water at pH 0. The interfacial charge difference and potential drop are presented, which further support the formation of a direct Z-scheme photocatalyst. More importantly, the PtS 2 /Are heterostructure has quite high solar-to-hydrogen (STH) efficiency (49.32%), significantly enhanced compared with isolated PtS 2 (12.67%) or Are (10.34%) monolayers. This direct Z-scheme PtS 2 /Are heterostructure with excellent STH efficiency suggests its promising application as a photocatalyst for water splitting.

Using first-principles calculations, we show that p-doped blue phosphorene can be obtained by molecular doping with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F 4 -TCNQ) and 1,3,4,5,7,8-hexafluorotetracyanonaphthoquinodimethane (F 6 -TNAP), whereas n-doped blue phosphorene can be realized by doping with tetrathiafulvalene (TTF) and cyclooctadecanonaene (CCO). Moreover, the doping gap can be effectively modulated in each case by applying an external perpendicular electric field. The optical absorption of blue phosphorene can be considerably enhanced in a broad spectral range through the adsorption of CCO, F 4 -TCNQ, and F 6 -TNAP molecules, suggesting potential of the doped materials in the field of renewable energy.

Herein, we report a comprehensive study on the structural and electronic properties of bulk, monolayer, and multilayer PdSe 2 sheets. First, we present a benchmark study on the structural properties of bulk PdSe 2 by using 13 commonly used density functional theory (DFT) functionals. Unexpectedly, the most commonly used van der Waals (vdW)-correction methods, including DFT-D2, optB88, and vdW-DF2, fail to provide accurate predictions of lattice parameters compared to experimental data (relative error > 15%). On the other hand, the PBE-TS series functionals provide significantly improved prediction with a relative error of <2%. Unlike hexagonal two-dimensional materials like graphene, transition metal dichalcogenides, and h-BN, the conduction band minimum of monolayer PdSe 2 is not located along the high symmetry lines in the first Brillouin zone; this highlights the importance of the structure-property relationship in the pentagonal lattice. Interestingly, high valley convergence is found in the conduction and valence bands in monolayer, bilayer, and trilayer PdSe 2 sheets, suggesting promising application in thermoelectric cooling., Competing Interests: The authors declare no competing financial interest.

The present study developed and implemented a new visco-hyperelastic model that is capable of predicting the time-dependent biomechanical behavior of the periodontal ligament. The constitutive model has been implemented into the finite element package ABAQUS by means of a user-defined material subroutine (UMAT). The stress response is decomposed into two constitutive parts in parallel which are a hyperelastic and a time-dependent viscoelastic stress response. In order to identify the model parameters, the indentation equation based on V-W hyperelastic model and the indentation creep model are developed. Then the parameters are determined by fitting them to the corresponding nanoindentation experimental data of the PDL. The nanoindentation experiment was simulated by finite element analysis to validate the visco-hyperelastic model. The simulated results are in good agreement with the experimental data, which demonstrates that the visco-hyperelastic model developed is able to accurately predict the time-dependent mechanical behavior of the PDL., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

This paper presents a method to design servo controllers for flexible ball screw drives with time-varying dynamics, which are mainly due to the time-varying table position and the workpiece mass. A gain-scheduled H∞ loop shaping controller is designed to achieve high tracking performance against the dynamic variations. H∞ loop shaping design procedure incorporates open loop shaping by a set of compensators to obtain performance/robust stability tradeoffs. The interpolating gain-scheduled controller is obtained by interpolating the state space model of the linear time-invariant (LTI) controllers estimated for fixed values of the scheduling parameters and a linear least squares problem can be solved. The proposed controller has been compared with P/PI with velocity and acceleration feedforward and adaptive backstepping sliding mode control experimentally. The experimental results indicate that the tracking performance has been improved and the robustness for time-varying dynamics has been achieved with the proposed scheme., (Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.)