摘要：Hierarchical heterostructure photocatalysts with broad spectrum solar light utilization,particularly in the nearinfrared(NIR)region,are emerging classes of advanced photocatalytic materials for solar-driven CO2 conversion into value-added chemical ***,a novel two-demensional/three-demensional(2 D/3 D)hierarchical composite is hydrothermally synthesized by assembling vertically-aligned ZnIn2 S4(ZIS)nanowall arrays on nitrogen-doped graphene foams(NGF).The prepared ZIS/NGF composite shows enhancement in photothermal conversion ability and selective CO2 capture as well as solar-driven CO2 ***273 K and 1 atm,the ZIS/NGF composite with 1.0 wt%NGF achieves a comparably high CO2-to-N2 selectivity of 30.1,with an isosteric heat of CO2 adsorption of 48.2 kJ mol^-*** in the absence of cocatalysts and sacrificial agents,the ZIS/NGF composite with cyclability converts CO2 into CH4,CO and CH3 OH under simulated solar light illumination,with the respective evolution rates about 9.1,3.5,and 5.9 times higher than that of the pristine ***-depth analysis using in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS)in conjunction with Kelvin probe measurements reveals the underlying charge transfer pathway and process from ZIS to NGF.

摘要：Liquid metals(LM) such as eutectic gallium-indium and gallium-indium-tin are important functional liquid-state metal materials with many unique properties, which have attracted wide attentions especially from soft robot area. Recently the amoeba-like transformations of LM on the graphite surface are discovered, which present a promising future for the design and assemble of self-fueled actuators with dendritically deformable body. It appears that the surface tension of the LM can be significantly reduced when it contacts graphite surface in alkaline solution. Clearly, the specific surface should play a vital role in inducing these intriguing behaviors, which is valuable and inspiring in soft robot design. However, the information regarding varied materials functions underlying these behaviors remains unknown. To explore the generalized effects of surface materials in those intriguing behavior, several materials including glass, graphite, nickel and copper oxides(CuO) were comparatively investigated as substrate *** results were obtained that only LM amoeba transformations were observed on graphite and CuO surfaces. In order to identify the proper surface condition for LM transformation, the intrinsic properties of substrate surfaces, such as the surface charge and roughness, as well as the specific interaction with LM like wetting behavior and mutual locomotion etc., were characterized. The integrated results revealed that LM droplet appears more likely to deform on surfaces with higher positive surface charge density, higher roughness and less bubble generation on them. In addition, another surface material,CuOx, is identified to own similar ability to graphite, which is valuable in achieving amoeba-like transformation. Moreover, this study offers a fundamental understanding of the surface properties in realizing LM amoeba transformations, which would shed light on packing and structure design of liquid metal-based soft device within multi-material s

摘要：Treatments for lesions in central nervous system(CNS)are always faced with challenges due to the anatomical and physiological particularity of the CNS despite the fact that several achievements have been made in early diagnosis and precision medicine to improve the survival and quality of life of patients with brain tumors in recent *** the complexity as well as role of the microenvironment of brain tumors may suggest a better revealing of the molecular mechanism of brain tumors and new therapeutic directions,which requires an accurate recapitulation of the complex microenvironment of human brain in ***,a 3D bioprinted in vitro brain matrix-mimetic microenvironment model with hyaluronic acid(HA)and normal glial cells(HEBs)is developed which simulates both mechanical and biological properties of human brain microenvironment in vivo through the investigation of the formulation of bioinks and optimization of printing process and parameters to study the effects of different concentration of gelatin(GA)within the bioink and different printing structures of the scaffold on the performance of the brain matrix-mimetic microenvironment *** study provides experimental models for the exploration of the multiple factors in the brain microenvironment and scaffolds for GBM invasion study.

摘要：In order to improve the trajectory tracking precision and reduce the synchronization error of a 6-DOF lightweight robot, nonlinear proportion-deviation （N-PD） cross-coupling synchronization control strategy based on adjacent coupling error analysis is presented. The mathematical models of the robot, including kinematic model, dynamic model and spline trajectory planing, are established and verified. Since it is difficult to describe the real-time contour error of the robot for complex trajectory, the adjacent coupling error is analyzed to solve the problem. Combined with nonlinear control and coupling performance of the robot, N-PD cross-coupling synchronization controller is designed and validated by simulation analysis. A servo control experimental system which mainly consists of laser tracking system, the robot mechanical system and EtherCAT based servo control system is constructed. The synchronization error is significantly decreased and the maximum trajectory error is reduced from 0.33 mm to 0.1 mm. The effectiveness of the control algorithm is validated by the experimental results, thus the control strategy can improve the robot＇s trajectory tracking precision significantly.

摘要：Carbon dioxide as a notorious greenhouse gas triggers severe global warming which is threatening the balance of ecosystem. In this respect, effectively capturing and transforming CO_(2)into value-added chemicals are essential but still challenging tasks. As a kind of emerging crystalline porous material, covalent organic frameworks(COFs) have been demonstrated to be able to adsorb gases and function as catalysts to facilitate chemical transformations. Herein, we report an imine-linked, cobalt sandwich complex-based COF(Co-BD-COF) with high crystallinity and large surface ***-BD-COF can efficiently catalyze the transformation of CO_(2)into cyclic carbonates due to abundant metal sites and high porosity. In addition, Co-BD-COF exhibits high catalytic selectivity toward small ethylene oxide derivatives in cycloaddition reaction due to the large steric hindrance around the cobalt complexes rendered by the peripheral phenyl *** new metal sandwich-type building block provides a new strategy for improving catalytic selectivity of COFs.

摘要：Left-hand materials have drawn increasing attention from many disciplines and found widespread application, especially in microwave engineering. A sandwiched metamaterial consisting of multi-nested square-split-ring resonators on the top side and a set of wires on the back side is proposed. Scattering parameters are retrieved by high-frequency structure simulator(HFSS) software based on the finite element method. Effects of square-split-ring number on the left-hand characteristics containing negative values of permittivity, permeability, and refractive index have been intensively investigated. Simulated results show that obvious resonant left-hand characteristics could be observed within 8-18 GHz, and the resonant frequency counts are inclined to be in direct proportion to the square-split-ring number over 8-18 GHz. Besides, the proposed sandwiched metamaterial with three square-split-ring resonators and three wires presents the widest frequency band of left-hand characteristics in a range of 8-18 GHz. Further, electromagnetic field distributions demonstrated that the induced magnetic dipole dominates the resonant absorption. The multi-peak resonance characteristics of square-split-ring resonant structure are considered to be a promising candidate for selective-frequency absorption or modulation toward microwave frequency band.

摘要：Micro-/nano-patterns on hydrogels are widely used in cell ***,manufacturing molds with traditional lithography is time-consuming and *** addition,the excessive demolding force can easily damage patterns since biocompatible hydrogels are ultra-soft or ***,we presented a novel method for rapid and mass fabrication of cell ***-precision three-dimensional(3D)printing was used to manufacture a mold with a resolution of 2µm,and the gelatin-based hydrogel was cured by thermal–photo-crosslinking so that the low-concentration and low-substitutionrate hydrogel could be demolded *** found that pre-cooling before illumination made gelatin-based hydrogels resilient due to the partial regain of triple-helix *** this method,arbitrarily customized hydrogel patterns with a feature size of 6–80µm can be fabricated stably and at low *** cardiomyocytes were seeded on ultra-soft hydrogels with parallel groove structures,a consistent and spontaneous beating with 216 beats per minute(BPM)could be observed,approaching the natural beating rate of rat hearts(300 BPM).Overall,this work provides a general scheme for manufacturing cell patterns which has great potential for cell ethology and tissue repair.

摘要：In this study, the effects of length-width ratio and diversion trench of the spacer on the fluid flow behavior in an electrodialyzer have been investigated through CFD simulation method. The relevant information, including the pressure drop, velocity vector distribution and shear stress distribution, demonstrates the importance of optimized design of the spacer in an electrodialysis process. The results show width of the diversion trench has a great effect on the fluid flow compared with length. Increase of the diversion trench width could strength the fluid flow, but also increase the pressure drop. Secondly, the dead zone of the fluid flow decreases with increase of length-width ratio of the spacer, but the pressure drop increases with the increase of length-width ratio of the spacer. So the appropriate length-width ratio of the space should be moderate.

摘要：The past 5 years have witnessed the rapid development of organic solar cells based on nonfullerene acceptors(NFAs)[1-26].The state-of-the-art NFA-based single-junction and tandem solar cells afforded 18.22%(certified 17.6%)and 17.36%(certified 17.29%)power conversion efficiencies(PCEs),respectively[27,28].Wide-bandgap(WBG)polymer donors are ideal partners for *** present complementary absorption with that of low-bandgap NFAs and deep the highest occupied molecular orbital(HOMO)***,solar cells based on a WBG polymer and a NFA can generate high short-circuit current density(Jsc)and open-circuit voltage(Voc)[29].Meanwhile,some WBG polymers show high crystallinity and mobility,gifting the solar cells high fill factors(FF)[30].Recently,our group first reported efficient WBG D-A copolymer donors based on fused-ring aromatic lactone(FRAL)acceptor units.

摘要：Soil shear strength is an important indicator of engineering design and an essential parameter of soil precision tillage and agricultural machinery and equipment design. Although numerous studies have investigated the characteristics of different soil shear strengths, only a few of these works have paid attention to soils containing considerable quantities of rock fragments. To date, most studies on the effects of rock fragments on the shear strength have paid attention to the role of rock fragments with sizes 〉2 mm. The effects of rock fragments 〈2 mm in soil are generally ignored. Similar to rock fragments 〉2 ram, the presence of rock fragments 〈2 mm could also change the mechanical properties of soils. Thus, in the present study we evaluated the potential influence of 〈2 mm rock fragments on soil shear strength via an unconsolidated undrained （UU） triaxial compression test. Our results were as follows： （1） A certain quantity of 〈2 mm rock fragments presented in purple soils developed from clay rocks; and an appropriate quantity of 〈2 mm rock fragments could improve the shear strength of soils. （2） The different PSDs of soils containin 〈2 mm rock fragment mainly caused variations in the internal friction angle of soils. （3） The shear strengths of the two mudstone-developed red-brown and gray-brown purple soils was more sensitive to water than that of the shale-developed coarse-dark purple soil. As the soil water content increased from 9% to 23%, the changes in the cohesion, internal friction angle, shear strength, and the maximum principal stress difference were smaller in the coarse dark purple soil than in the two other soils. We therefore concluded that 〈2 mm rock fragments in purple soils exerted important effects on soil shear strength. A better understanding of the differences among the shear strength features of purple soils could help improve the design of agricultural machinery and equipment.