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1High-speed femtosecond laser plasmonic lithography and reduction of graphene oxide for anisotropic photoresponse显示文摘Micro/nanoprocessing of graphene surfaces has attracted significant interest for both science and applications due to its effective modulation of material properties,which,however,is usually restricted by the disadvantages of the current fabrication methods.Here,by exploiting cylindrical focusing of a femtosecond laser on graphene oxide(GO)films,we successfully produce uniform subwavelength grating structures at high speed along with a simultaneous in situ photoreduction process.Strikingly,the well-defined structures feature orientations parallel to the laser polarization and significant robustness against distinct perturbations.The proposed model and simulations reveal that the structure formation is based on the transverse electric(TE)surface plasmons triggered by the gradient reduction of the GO film from its surface to the interior,which eventually results in interference intensity fringes and spatially periodic interactions.Further experiments prove that such a regular structured surface can cause enhanced optical absorption(>20%)and an anisotropic photoresponse(~0.46 ratio)for the reduced GO film.Our work not only provides new insights into understanding the laser-GO interaction but also lays a solid foundation for practical usage of femtosecond laser plasmonic lithography,with the prospect of expansion to other two-dimensional materials for novel device applications.Tingting Zou Bo Zhao Wei Xin Ye Wang Bin Wang Xin Zheng Hongbo Xie Zhiyu Zhang Jianjun Yang Chunlei Guo 2020Light(Science & Applications)2020,9,1:17
2Emerging in-plane anisotropic two-dimensional materials显示文摘Black phosphorus(BP)is a rapidly up and coming star in two-dimensional(2D)materials.The unique characteristic of BP is its in-plane anisotropy.This characteristic of BP ignites a new type of 2D materials that have low-symmetry structures and in-plane anisotropic properties.On this basis,they offer richer and more unique low-dimensional physics compared to isotropic 2D materials,thus providing a fertile ground for novel applications including electronics,optoelectronics,molecular detection,thermoelectric,piezoelectric,and ferroelectric with respect to in-plane anisotropy.This article reviews the recent advance in characterization and applications of in-plane anisotropic 2D materials.Liang Li Wei Han Lejing Pi Ping Niu Junbo Han Chengliang Wang Bin Su Huiqiao Li Jie Xiong Yoshio Bando Tianyou Zhai 2019InfoMat2019,1,1:16
3Preparation and anisotropic properties of textured structural ceramics: A review显示文摘Ceramics are usually composed of randomly oriented grains and intergranular phases, so their properties are the statistical average along each direction and show isotropy corresponding to the uniform microstructures. Some methods have been developed to achieve directional grain arrangement and preferred orientation growth during ceramic preparation, and then textured ceramics with anisotropic properties are obtained. Texture microstructures give particular properties to ceramics along specific directions, which can effectively expand their application fields. In this review, typical texturing techniques suitable for ceramic materials, such as hot working, magnetic alignment, and templated grain growth(TGG), are discussed. Several typical textured structural ceramics including α-Al2O3 and related nacre bioinspired ceramics, Si3N4 and SiAlON, h-BN, MB2 matrix ultra-high temperature ceramics, MAX phases and their anisotropic properties are presented.Zhuo ZHANG Xiaoming DUAN Baofu QIU Zhihua YANG Delong CAI Peigang HE Dechang JIA Yu ZHOU 2019Journal of Advanced Ceramics2019,8,3:14
4The texture and its optimization in magnesium alloy显示文摘The crystallographic orientations are generally non-random in wrought Mg alloy,which will lead to their macroscopic physical properties to be anisotropic.Understanding the texture evolution in processing of Mg alloy billets and its effect on mechanical properties is therefore an important project for all scientists and engineers in material area.This paper is concerned with the description of texture,with the mechanisms of texture evolution and with the interrelationships between texture and mechanical properties in Mg alloy.It is a full review of understanding of the basic mechanism on texture evolution,of texture altering by alloying or processing,and of the mechanism of texture weakening.Moreover,it provides theories necessary and available techniques to develop high-performance Mg wrought with optimized texture in the field.Jialin Wu Li Jin Jie Dong Fenghua Wang Shuai Dong 2020Journal of Materials Science & Technology2020,42,7:13
5Implications for rock instability precursors and principal stress direction from rock acoustic experiments显示文摘The characteristics of rock instability precursors and the principal stress direction are very crucial for the prevention of geological disasters.This study investigated the qualitative relationship between rock instability precursors and principal stress direction through wave velocity in rock acoustic emission(AE)experiments.Results show that the wave velocity variation exhibits obvious anisotropic characteristics in 0%–20%and 60%–90%of peak strength due to the differences of stress-induced microcrack types.The amplitude of wave velocity variation is related to the azimuth and position of wave propagation path,which indicates that the principal stress direction can be identified by the anisotropic characteristics of wave velocity variations.Furthermore,the experiments also demonstrate that the AE event rate and wave velocity show quiet and stable variations in the elastic stage of rock samples,while they present a trend of active and unstable variations in the plastic stage.It implies that both the AE event rate and wave velocity are effective monitoring parameters for rock instability.The anisotropic characteristics of the wave velocity variation and AE event rate are beneficial complements for identifying the rock instability precursors and determining the principal stress direction,which provides a new analysis method for stability monitoring in practical rock engineering.Longjun Dong Yongchao Chen Daoyuan Sun Yihan Zhang 2021International Journal of Mining Science and Technology2021,31,5:10
6Negative reflection and negative surface wave conversion from obliquely incident electromagnetic waves显示文摘Complete control of spatially propagating waves(PWs)and surface waves(SWs)is an ultimate goal that scientists and engineers seek for,in which negative reflection of PW and negative surface wave are two exotic phenomena.Here,we experimentally demonstrate an anisotropic digital coding metasurface capable of controlling both PWs and SWs with a single coding pattern.On the basis of the digital description of coding metasurfaces,a simple coding method is proposed to allow dual functionalities(either PW or SW manipulations)under two orthogonal polarizations at arbitrarily oblique incidences,thus improving the adaptability of digital coding metasurfaces in more practical circumstances.With elaborately designed ellipse-shaped coding particles,we experimentally demonstrate various functions under oblique incidences,including the negative reflection of PW,negative SW,anomalous reflection and their arbitrary combinations,all having good agreements with theoretical and numerical predictions.We believe that the proposed method may enable the digital coding metasurfaces to have broad applications in radar detections,wireless communications and imaging.Shuo Liu Tie Jun Cui Ahsan Noor Zui Tao Hao Chi Zhang Guo Dong Bai Yan Yang Xiao Yang Zhou 2018Light(Science & Applications)2018,7,1:10
7Equivalent Currents on an Anisotropic MaterialBacked by a Metal Surface and Their Relation显示文摘Based on a first-order state-vector differential equation representation of Maxwell’s equations, an analytical formulation is derived for the equivalent currents on an anisotropic material backed by a metal surface, and the relation between two currents is also considered. These expressions are degenerated into the common forms for some simple cases. This effort will provide the theoretical preparation for the approximate calculation of electromagnetic scattering from a conducting object coated by an anisotropic material.Huang Peikang Yin Hongcheng 2000Journal of Systems Engineering and Electronics2000,11,4:10
8Behavior of noncircular tunnels excavated in stratified rock masses-Case of underground coal mines显示文摘The amount of tunnels excavated along stratified/sedimentary rock masses in Quangninh coal mine area,Vietnam, is gradually increasing. Rock mass in Quangninh is characterized by beddings between rock layers. The behavior of stratified rock masses surrounding the tunnels depends on both the intact rock and the beddings between rock layers. The main characteristics of stratified rock masses that need to be considered are their heterogeneity and anisotropy. Depending on the dip angle of rock layers, movements and failure zones developed surrounding the tunnels can be asymmetrical over the vertical axis of tunnel. This asymmetry causes adverse behaviors of the tunnel structures. The objective of this study is to highlight convergences and yielded zones developed in rock masses surrounding noncircular tunnels in Quangninh coal mine area using a finite element method. The presence of bedding joints is explicitly simulated. The numerical results indicated that with the increase in dip angle of bedding joints, the stress asymmetry over the tunnel vertical axis increases. It gradually leads to an asymmetry of the failure zone surrounding the tunnel. An increase of rock mass quality means a decrease of rock mass sensitivity to the discontinuities. In addition,a dip angle of the bedding joints of approximately 45° could be considered as the critical angle at which the rock mass mechanism changes between sliding and bending.Ngoc Anh Do Daniel Dias Van Diep Dinh Tien Tung Tran Van Canh Dao Viet Doan Dao Phuc Nhan Nguyen 2019Journal of Rock Mechanics and Geotechnical Engineering2019,11,1:9
9Polynomials,Higher Order Sobolev Extension Theorems and Interpolation Inequalities on Weighted Folland-Stein Spaces on Stratified GroupsGuozhen Lu Department of Mathematics,Wayne State University,Detroit,MI 48202,USA 2000Acta Mathematica Sinica,English Series2000,16,3:9
10Optical and electrical properties of two-dimensional anisotropic materials显示文摘Two-dimensional(2D) anisotropic materials, such as B-P, B-As, GeSe, GeAs, ReSe2, KP15 and their hybrid systems, exhibit unique crystal structures and extraordinary anisotropy. This review presents a comprehensive comparison of various 2D anisotropic crystals as well as relevant FETs and photodetectors, especially on their particular anisotropy in optical and electrical properties. First, the structure of typical 2D anisotropic crystal as well as the analysis of structural anisotropy is provided. Then, recent researches on anisotropic Raman spectra are reviewed. Particularly, a brief measurement principle of Raman spectra under three typical polarized measurement configurations is introduced. Finally, recent progress on the electrical and photoelectrical properties of FETs and polarization-sensitive photodetectors based on 2D anisotropic materials is summarized for the comparison between different 2D anisotropic materials. Beyond the high response speed, sensitivity and on/off ratio, these 2D anisotropic crystals exhibit highly conduction ratio and dichroic ratio which can be applied in terms of polarization sensors, polarization spectroscopy imaging, optical radar and remote sensing.Ziqi Zhou Yu Cui Ping-Heng Tan Xuelu Liu Zhongming Wei 2019Journal of Semiconductors2019,40,6:9
11THE IDT WITH HIGH INTERNAL REFLECTION SUPPRESSION显示文摘Based on Chen-Haus′theory,an experimental research on the reflection of SAW from ashort-circuited Au-grating on YZ LiNbO3 and a short-circuited Al-recessed groove grating on ST-Xquartz is first presented in this paper where an anomalous reflection phenomena existing in two gratings areconfirmed.In addition,a residual reflection which couldn′t be completely cancelled by means of changingstrip-thickness is pointed out for a short-circuited Au-grating on YZ LiNbO3 both experimentally andtheoretically through extending Chen-Haus′theory to anisotropic crystals.Finally.two kinds of IDT composed of single electrodes:Au-electrode on YZ LiNbO3 and Al-recessed-groove-electrode on ST-X quartz,are proposed for high internal reflection suppression.The experimental results of bandpass filters constructed with the IDTs mentioned above show a great im-provement in passband distortion and a potential usefulness of new structure in high frequency range.HE Shitang CHEN Dongpei and WANG Chenghao(Institute of Acoustics, Academia Sinica) 1989Chinese Journal of Acoustics1989,8,4:7
12Conversion between polarization states based on a metasurface显示文摘Transmission of an anisotropic metasurface is analyzed in a polar base relying on the Jones calculus, and polarization conversion from the spatial uniform polarization to the spatial nonuniform polarization is explored.Simple and compact polarization converters based on rectangular holes or cross holes etched in silver film are designed, and polarization conversions from the linear and circular polarization to the radial and azimuthal polarization are realized. Numerical simulations of three designed polarization converters consisting of rectangular holes equivalent to polarizers and quarter-and half-wave plates, exhibit the perfect polarization conversion.The experiment results consistent with the simulations verify theoretic predictions. This study is helpful for designing metasurface polarization converters and expanding the application of a metasurface in polarization manipulations.SHUYUN TENG QI ZHANG HAN WANG LIXIA LIU HAORAN LV 2019Photonics Research2019,7,3:7
13Interpolation theory of anisotropic finite elements and applications显示文摘Interpolation theory is the foundation of finite element methods.In this paper,after reviewing some existed interpolation theorems of anisotropic finite element methods,we present a new way to analyse the interpolation error of anisotropic elements based on Newton's formula of polynomial interpolation as well as its applications.CHEN ShaoChun XIAO LiuChao 2008Science China Mathematics2008,51,8:7
14Anisotropic weak Hardy spaces and interpolation theorems显示文摘In this paper, the authors establish the anisotropic weak Hardy spaces associated with very general discrete groups of dilations. Moreover, the atomic decomposition theorem of the anisotropic weak Hardy spaces is also given. As some applications of the above results, the authors prove some interpolation theorems and obtain the boundedness of the singular integral operators on these Hardy spaces.DING Yong LAN SenHua 2008Science China Mathematics2008,51,9:6
15MRS and diffusion tensor image in mild traumatic brain injuries显示文摘Objective:To analyze characters of magnetic resonance spectroscopy(MRS) and diffusion tensor imaging(DTI) in the diagnosis of mild trauma brain injuries(MTBI) in frontal lobe and to compare with conventional magnetic resonance imaging(MRI).Methods:A total of 21 patients were selected,who all aged 12-51 years old and had injury within 24 hours.Computer tomography (CT) and the Glasgow Coma Scale were used to evaluate the degree of injury.All patients were diagnosed as MTBI,and 19 had conventional MRI,MRS and DTI.The major parameters of MRS were Probe-P sequence,TE= 144 or 35 ms,and both single voxel spectrum and chemical shift imging were included.The major parameters of DTI were diffusion directions =15,b value = 1000 s/mm^2. Frational anisotropic(FA) map and average ADC map were obtained to evaluate DTI result. Positive deletion ratio was observed and the imaging changes were compared between injured side and normal side.Results:All 21 patients had CT scan and Glasgow scale.A total of 19 patients had conventional MRI.DTI and MRS.Results of CT and conventional MRI showed no significant abnormality in lobe,and Glasgow scale showed mild type.MRS result showed significant decrease in N-acetyl aspartate(NAA) and NAA/creatine(Cr) in 13 cases(68.4%) (P<0.001),and increase in lactic acid(Lac) in 7 cases(36.8%).FA mapping of the frontal lobe displayed significant changes in 7 cases(36.8%),with 5 out of the 7 cases having increase in FA value.And there was no significant difference in average ADC.Conclusions:MRS and DTI might be more sensible than other methods,such as CT and conventional MRI in diagnosis of MTBI.The particular changes were reduced NAA and increased Lac for MRS.and increased FA values for DTI.Jing Chen Hu Jin Ying Zhang Qizhou Liang Haiyan Liao Ziyi Guo Xiangjun Han 2012Asian Pacific Journal of Tropical Medicine2012,5,1:6
16Preliminary Discussion on the Relationship Between EM Wave Propagation Characteristics and Medium Parameters in Anisotropic Medium显示文摘The reflection and transmission characteristics of an anisotropic half-space medium normally illuminated by aplane wave are analyzed by kDB coordination. The general formula of reflection coefficient at the air-medium interface isgiven, and its validity is also discussed. The possible propagating modes in different mediums and the effect of medium pa-rameters on these modes are emphatically studied. This work provides the theoretical preparations for the parameter recon-struction of an anisotropic material.Guo Huiping & Liu Xueguan Dept. of Communication and Electronics, Suzhou University, Suzhou 215021, P. R. ChinaYin Hongcheng & Huang Peikang National Electromagnetic Scattering Laboratory, Beijing 100854, P. R. China 2002Journal of Systems Engineering and Electronics2002,13,4:6
17Heterostructures in two-dimensional colloidal metal chalcogenides:Synthetic fundamentals and applications显示文摘As a new class of two-dimensional materials, two-dimensional (2D) heterostructures constructed from metal chalcogenides (MCs) have been gaining tremendous attention due to their unprecedented physical and chemical phenomena, mainly originated from their distinct structural features such as composition, architecture type, spatial arrangement of each component, crystal structure, exposed facet and interface, dimensionality in their heterostructures. Towards the realization of practical applications, synthetic approaches need a rational design with a variety of architecture types including laterally-combined, vertically-aligned, and conformally-coated 2D MC heterostructures. Among various synthetic routes, solution-based synthesis is thought of as an alternative to fabrication through high-cost setups since it can control those structural features in a cheap fashion. This review presents recent progress on solution-based synthesis to produce various 2D MC heterostructures with a focus on the synthetic fundamentals in terms of thermodynamic and kinetic aspects related to the growth mechanism. Four different synthetic approaches are reviewed: seeded growth, cation exchange reaction, colloidal atomic layer deposition, direct synthesis including one-step process and modified electrochemical method. We also provide some representative applications of 2D MC heterostructures and their hybrid composites in various fields including optoelectronics, thermoelectrics, catalysis, and battery. Finally, we offer an insight into challenges and future directions in a synthetic improvement of 2D MC heterostructures.Yuho Min Eunmi Im Geon-Tae Hwang Jong-Woo Kim Cheol-Woo Ahn Jong-Jin Choi Byung-Dong Hahn Joon-Hwan Choi Woon-Ha Yoon Dong-Soo Park Dong Choon Hyun Geon Dae Moon 2019Nano Research2019,12,8:6
18EIGEN THEORY OF ELASTIC DYNAMICS FOR ANISOTROPIC SOLIDS显示文摘1INTRODUCTIONTheconceptofeigenelasticityoriginatedfromKelvin’swork[1,2].Itisinlastdecadethateigenelasticitywasstudiedagainand...Guo, Shaohua 1999中国有色金属学会会刊:英文版1999,9,2:6
19Uniform dimension results for Gaussian random fields显示文摘Let X = {X(t),t ∈ RN} be a Gaussian random field with values in Rd defined by X(t) =(X1(t),...,Xd(t)), t ∈ RN.(1) The properties of space and time anisotropy of X and their connections to uniform Hausdorff dimension results are discussed.It is shown that in general the uniform Hausdorff dimension result does not hold for the image sets of a space-anisotropic Gaussian random field X.When X is an(N,d)-Gaussian random field as in(1),where X1,...,Xd are independent copies of a real valued,centered Gaussian random field X0 which is anisotropic in the time variable.We establish uniform Hausdorff dimension results for the image sets of X.These results extend the corresponding results on one-dimensional Brownian motion,fractional Brownian motion and the Brownian sheet.WU DongSheng XIAO YiMin 2009Science China Mathematics2009,52,7:6
20Direct numerical simulation of turbulent boundary layer over an anisotropic compliant wall显示文摘Direct numerical simulation of a spatially developing turbulent boundary layer over a compliant wall with anisotropic wall material properties is performed. The Reynolds number varies from 300 to approximately 860 along the streamwise direction, based on the external flow velocity and the momentum thickness. Eight typical cases are selected for numerical investigation under the guidance of the monoharmonic analysis. The instantaneous flow fields exhibit the traveling wavy motion of the compliant wall, and the frequency-wavenumber power spectrum of wall pressure fluctuation is computed to quantify the mutual influence of the wall compliance and the turbulent flow at different wave numbers. It is shown that the Reynolds shear stress and the pressure fluctuation are generally enhanced by the wall compliance with the parameters considered in the present study. A dynamical decomposition of the skin-friction coefficient is derived, and a new term (CW) appears due to the wall-induced Reynolds shear stress. The influence of the anisotropic compliant wall motion on the turbulent boundary layer through the wall-induced negative Reynolds shear stress is discussed. To elucidate the underlying mechanism, the budget analysis of the Reynolds stresses transportation is further carried out. The impact of the wall compliance on the turbulent flow is disclosed by examining the variations of the diffusion and velocity-pressure correlation terms. It is shown that increase of the Reynolds stresses inside the flow domain is caused by enhancement of the velocity-pressure correlation term, possibly through the long-range influence of the wall compliance on the pressure field, rather than diffusion of the wall-induced Reynolds shear stress into the fluid flow.Qian-Jin Xia Wei-Xi Huang Chun-Xiao Xu 2019Acta Mechanica Sinica2019,35,2:5
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