The finite-difference time-domain method is used to simulate the optical characteristics of an in-plane switching blue phase liquid crystal display.Compared with the matrix optic methods and the refractive method,the ...The finite-difference time-domain method is used to simulate the optical characteristics of an in-plane switching blue phase liquid crystal display.Compared with the matrix optic methods and the refractive method,the finite-difference timedomain method,which is used to directly solve Maxwell＇s equations,can consider the lateral variation of the refractive index and obtain an accurate convergence effect.The simulation results show that e-rays and o-rays bend in different directions when the in-plane switching blue phase liquid crystal display is driven by the operating voltage.The finitedifference time-domain method should be used when the distribution of the liquid crystal in the liquid crystal display has a large lateral change.展开更多
Au nanostructures were prepared on uniform Cu2O octahedra and rhombic dodecahedra via the galvanic replacement reaction between HAuCl 4 and Cu2O. The compositions and structures were studied by Scanning Electron Micro...Au nanostructures were prepared on uniform Cu2O octahedra and rhombic dodecahedra via the galvanic replacement reaction between HAuCl 4 and Cu2O. The compositions and structures were studied by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), High-Resolution Transmission Electron Microscope (HRTEM), X-Ray Diffraction (XRD), X-Ray Absorption Spectroscopy (XAS), X-ray Photoelectron Spectroscopy (XPS) and in-situ DRIFTS spectroscopy of CO adsorption. Different from the formation of Au-Cu alloys on Cu2O cubes by the galvanic replacement reaction (ChemNanoMat 2 (2016) 861-865), metallic Au particles and positively-charged Au clusters form on Cu2O octahedra and rhombic dodecahedra at very small Au loadings and only metallic Au particles form at large Au loadings. Metallic Au particles on Cu2O octahedra and rhombic dodecahedra are more active in catalyzing the liquid phase aerobic oxidation reaction of benzyl alcohol than positively-charged Au clusters. These results demonstrate an obvious morphology effect of Cu2O nanocrystals on the liquid-solid interfacial reactions and prove oxide morphology as an effective strategy to tune the surface reactivity and catalytic performance. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
Low-temperature CO oxidation has attracted extensive interest in heterogeneous catalysis because of the potential applications in fuel cells,air cleaning,and automotive emission reduction.In the present study,theoreti...Low-temperature CO oxidation has attracted extensive interest in heterogeneous catalysis because of the potential applications in fuel cells,air cleaning,and automotive emission reduction.In the present study,theoretical investigations have been performed using density functional theory to elucidate the crystal plane effect and structure sensitivity of Co3O4 nano-catalysts toward catalyzing CO oxidation.It is shown that the surface Co–O ion pairs are the active site for CO oxidation on the Co3O4 surface.Because of stronger CO adsorption and easier removal of lattice oxygen ions,the Co3O4（011）surface is shown to be more reactive for CO oxidation than the Co3O4（001）surface,which is consistent with previous experimental results.By comparing the reaction pathways at different sites on each surface,we have further elucidated the nature of the crystal plane effect on Co3O4 surfaces and attributed the reactivity to the surface reducibility.Our results suggest that CO oxidation catalyzed by Co3O4 nanocrystals has a strong crystal plane effect and structure sensitivity.Lowering the vacancy formation energy of the oxide surface is key for high CO oxidation reactivity.展开更多
The nanohardness is from 1.44 to 2.61 GPa,the Vickers hardness is from 127 to 252 Vickers,and elastic modulus is from 52 to 123 GPa by the nanoindentation experiments on the doubler plane of KDP crystal. An indentatio...The nanohardness is from 1.44 to 2.61 GPa,the Vickers hardness is from 127 to 252 Vickers,and elastic modulus is from 52 to 123 GPa by the nanoindentation experiments on the doubler plane of KDP crystal. An indentation size effect is observed on the doubler plane in the test as the nanohardness and elastic modulus decreases with the increase of the maximum load.Slippage is identified as the major mode of plastic deformation, and pop-in events are attributed to the initiation of slippage.And the variation of unloading curve end is the result of stick effects between the indenter and the contact surface.The depth of the elastic deformation,which is between 40 and 75 nm,is responsible for the elastic deformation.The doubler plane of KDP crystal has anisotropy,and the relative anisotropy of nanohardness is 8.2%and the relative anisotropy of elastic modulus is 8.0%.展开更多
通过微波等离子体化学气相淀积技术生长单晶金刚石并切割得到(110)和(111)晶面金刚石片,以同批器件工艺制备两种晶面上栅长为6μm的氢终端单晶金刚石场效应管,从材料和器件特性两方面对两种晶面金刚石进行对比分析.(110)面和(111)面金...通过微波等离子体化学气相淀积技术生长单晶金刚石并切割得到(110)和(111)晶面金刚石片,以同批器件工艺制备两种晶面上栅长为6μm的氢终端单晶金刚石场效应管,从材料和器件特性两方面对两种晶面金刚石进行对比分析.(110)面和(111)面金刚石的表面形貌在氢终端处理后显著不同,光学性质则彼此相似.VGS=–4 V时,(111)金刚石器件获得的最大饱和电流为80.41 m A/mm,约为(110)金刚石器件的1.4倍;其导通电阻为48.51 W·mm,只有(110)金刚石器件导通电阻的67%.通过对器件电容-电压特性曲线的分析得到,(111)金刚石器件沟道中最大载流子密度与(110)金刚石器件差异不大.分析认为,(111)金刚石器件获得更高饱和电流和更低导通电阻,应归因于较低的方阻.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11304074,61475042,and 11274088)the Natural Science Foundation of Hebei Province,China(Grant Nos.A2015202320 and GCC2014048)the Key Subject Construction Project of Hebei Province University,China
文摘The finite-difference time-domain method is used to simulate the optical characteristics of an in-plane switching blue phase liquid crystal display.Compared with the matrix optic methods and the refractive method,the finite-difference timedomain method,which is used to directly solve Maxwell＇s equations,can consider the lateral variation of the refractive index and obtain an accurate convergence effect.The simulation results show that e-rays and o-rays bend in different directions when the in-plane switching blue phase liquid crystal display is driven by the operating voltage.The finitedifference time-domain method should be used when the distribution of the liquid crystal in the liquid crystal display has a large lateral change.
基金supported by the National Basic Research Program of China(2013CB933104)the National Natural Science Foundation of China(21525313,21173204,21373192,U1332113)+1 种基金MOE Fundamental Research Funds for the Central Universities(WK2060030017)Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘Au nanostructures were prepared on uniform Cu2O octahedra and rhombic dodecahedra via the galvanic replacement reaction between HAuCl 4 and Cu2O. The compositions and structures were studied by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), High-Resolution Transmission Electron Microscope (HRTEM), X-Ray Diffraction (XRD), X-Ray Absorption Spectroscopy (XAS), X-ray Photoelectron Spectroscopy (XPS) and in-situ DRIFTS spectroscopy of CO adsorption. Different from the formation of Au-Cu alloys on Cu2O cubes by the galvanic replacement reaction (ChemNanoMat 2 (2016) 861-865), metallic Au particles and positively-charged Au clusters form on Cu2O octahedra and rhombic dodecahedra at very small Au loadings and only metallic Au particles form at large Au loadings. Metallic Au particles on Cu2O octahedra and rhombic dodecahedra are more active in catalyzing the liquid phase aerobic oxidation reaction of benzyl alcohol than positively-charged Au clusters. These results demonstrate an obvious morphology effect of Cu2O nanocrystals on the liquid-solid interfacial reactions and prove oxide morphology as an effective strategy to tune the surface reactivity and catalytic performance. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
基金supported by the National Basic Research Program of China(2011CB932401)the National Natural Science Foundation of China(21221062)~~
文摘Low-temperature CO oxidation has attracted extensive interest in heterogeneous catalysis because of the potential applications in fuel cells,air cleaning,and automotive emission reduction.In the present study,theoretical investigations have been performed using density functional theory to elucidate the crystal plane effect and structure sensitivity of Co3O4 nano-catalysts toward catalyzing CO oxidation.It is shown that the surface Co–O ion pairs are the active site for CO oxidation on the Co3O4 surface.Because of stronger CO adsorption and easier removal of lattice oxygen ions,the Co3O4（011）surface is shown to be more reactive for CO oxidation than the Co3O4（001）surface,which is consistent with previous experimental results.By comparing the reaction pathways at different sites on each surface,we have further elucidated the nature of the crystal plane effect on Co3O4 surfaces and attributed the reactivity to the surface reducibility.Our results suggest that CO oxidation catalyzed by Co3O4 nanocrystals has a strong crystal plane effect and structure sensitivity.Lowering the vacancy formation energy of the oxide surface is key for high CO oxidation reactivity.
基金supported by the State Key Project of Fundamental Research for Nanoscience and Nanotechnology (2011CB932401)the National Natural Science Foundation of China (21221062, 10979031)~~
基金supported by the National Natural Science Foundation of China(No.51135002)the Natural Science Foundation of Liaoning Province of China(No.20102027)the Open Foundation of State Key Laboratory of Tribology of Tsinghua University(No. SKLTKF09B03)
文摘The nanohardness is from 1.44 to 2.61 GPa,the Vickers hardness is from 127 to 252 Vickers,and elastic modulus is from 52 to 123 GPa by the nanoindentation experiments on the doubler plane of KDP crystal. An indentation size effect is observed on the doubler plane in the test as the nanohardness and elastic modulus decreases with the increase of the maximum load.Slippage is identified as the major mode of plastic deformation, and pop-in events are attributed to the initiation of slippage.And the variation of unloading curve end is the result of stick effects between the indenter and the contact surface.The depth of the elastic deformation,which is between 40 and 75 nm,is responsible for the elastic deformation.The doubler plane of KDP crystal has anisotropy,and the relative anisotropy of nanohardness is 8.2%and the relative anisotropy of elastic modulus is 8.0%.
文摘通过微波等离子体化学气相淀积技术生长单晶金刚石并切割得到(110)和(111)晶面金刚石片,以同批器件工艺制备两种晶面上栅长为6μm的氢终端单晶金刚石场效应管,从材料和器件特性两方面对两种晶面金刚石进行对比分析.(110)面和(111)面金刚石的表面形貌在氢终端处理后显著不同,光学性质则彼此相似.VGS=–4 V时,(111)金刚石器件获得的最大饱和电流为80.41 m A/mm,约为(110)金刚石器件的1.4倍;其导通电阻为48.51 W·mm,只有(110)金刚石器件导通电阻的67%.通过对器件电容-电压特性曲线的分析得到,(111)金刚石器件沟道中最大载流子密度与(110)金刚石器件差异不大.分析认为,(111)金刚石器件获得更高饱和电流和更低导通电阻,应归因于较低的方阻.
