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Even-odd layer-dependent multiferroic in freestanding rare-earth orthorhombic perovskite

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Science china(Physics,Mechanics & Astronomy) 2024年第7期67卷 151-157页

作者： Shaowen xu Fanhao Jia ning Dai school of Physics and Optoelectronic Engineering Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China department of Physics College of ScienceHangzhou Dianzi UniversityHangzhou 310018China State Key Laboratory of Infrared Physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China

Freestanding oxide perovskites possess strong interlayer coupling between adjacent atomic layers,thus exerting a determinative effect on the magnetism and ferroelectricity of these atomic-scale ***,we propose an effective strategy to manipulate magnetism and ferroelectricity in freestanding rare-earth orthorhombic perovskite via modulation of layer *** performing first-principles calculations,an even-odd oscillation is demonstrated in few-layer GdAlO_(3)perovskite(GAP).Specifically,odd-layer systems with charged atomic layers are ferromagnetic polar metals,while even-layer systems are antiferromagnetic ferroelectric *** thickness-dependent magnetic phase transition originates from carrier doping,as rationalized by the Stoner ***,we demonstrate the promotion of in-plane ferroelectricity via the concurrent application of two distinct antiferrodistortive displacements,each driven by formation and breaking of *** multiferroic phases may emerge in other transition metal oxide perovskites supporting multiple valence states,e.g.,few-layer Gd MO_(3)(M=V,Cr,Mn,and Ni).This work puts forward a strategy for layer thickness engineering of magnetism and ferroelectricity in 2D oxide perovskite multiferroic materials.

关键词： few-layer rare-earth perovskite multiferroicity size effect first principles calculations

Molecular mechanism of dehydrin in response to environmental stress in plant

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Progress in Natural Science:Materials International 2007年第3期17卷 237-246页

作者： ZHANG Yuxiu , WANG Zi and xu Jin (department of Bioengineering, school of Chemical and Environmental Engineering, china University of Mining and Technology (beijing), beijing 100083, china department of Biology, graduate University of chinese academy of sciences, beijing 100049, china) [a]department of Bioengineering School of Chemical and Environmental Engineering China University of Mining and Technology (Beiing) Beijing China [b]department of Biology Graduate University of Chinese Academy of Sciences Beijing China

Dehydrins, known as the D-11 subgroup of late embryogenesis abundant (LEA) protein, are an immunologically distinct family of proteins, which typically accumulate in desiccation-tolerant seed embryo or in vegetative tissues in response to various environmental stresses such as drought, salinity and freezing. The existence of conservative sequences designated as K, S, and Y segments is a structural feature of dehydrins, and the K segment found in all dehydrins represents a highly conserved 15 amino acid motif (EKKGIMDKIKEKLPG) and forms an amphiphilicα-helix. According to the arrangement of these domains and clustering analysis, dehydrins are subdivided into 5 subtypes: YnSK, Kn, KnS, SKn and YnK. Different types of dehydrins are induced by different environmental stress in plants. Study results showed that dehydrins might play important protective roles under abiotic stress via a number of different mechanisms, including improving or protecting enzyme activities by the cryoprotective activity in responding to freeze/thaw or dehydration; stabilizing vesicles or other endomembrane structures by function as the membrane stabilizer during freeze induced dehydration, and preventing the membrane system from the oxidative damage induced by reactive oxygen radicals as the radical scavenger. Here, the gene expression and molecular mechanisms of dehydrin in response to stress in plants are discussed.

关键词： dehydrin stress mechanism.

The remarkable effect of amino hydrogen on membrane permeability and organelle staining of 1,8-naphthalimide dyes

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chinese Chemical Letters 2024年第2期35卷 347-351页

作者： Zhifeng Li Qinglong Qiao ning xu Kai An Wenchao Jiang Yi Tao Pengjun Bao Yinchan Zhang Zhaochao xu school of Chemistry Dalian University of TechnologyDalian 116024China CAS Key Laboratory of Separation Science for Analytical Chemistry Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of chinese academy of sciences Beijing 100049China

Membrane permeability and intracellular diffusion of fluorescent probes determine staining selectivity of intracellular ***,the relationship between the molecular structure of fluorescent probes and their membrane permeability and intracellular distribution is poorly *** this paper,we reported a series of 1,8-naphthalimide dyes and carried out cell imaging experiments,and found that the presence of amino hydrogen in these dyes played a crucial role in their cell membrane permeability and intracellular *** secondary amino group containing compounds 1-4 show excellent membrane permeability and strong fluorescence in living *** the tertiary amine containing dyes 5 and 6 can hardly permeate the cell membrane though they show extremely similar structure with compounds *** 1 can selectively image lipid droplets by selecting the wavelength of excitation *** the specificity for lysosomes,2 and 4 have been used in long-term time-lapses imaging of lysosomal dynamics and tracking the process of lysosome-lysosome interaction,fusion and *** effect of hydrogen-containing amino substituent on the cell membrane permeability of fluorescent molecules is promising for the development of better biocompatible probes.

关键词： Amino hydrogen 1,8-Naphthalimide Cell permeability Lipid droplet Lysosome

Fast Fourier-Galerkin methods for first-kind logarithmic-kernel integral equations on open arcs

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Science china mathematics 2010年第1期53卷 1-22页

作者： WANG Bo1,WANG Rui2 & xu YueSheng3,4,1academy of mathematics and Systems Science,chinese academy of sciences,beijing 100190,china 2school of Information Science and Engineering,graduate University of the chinese academy of sciences,beijing 100190,china 3department of mathematics,Syracuse University,Syracuse,NY 13244,USA 4department of Scientific Computing and Computer Applications,Sun Yat-sen University,Guangzhou 510275,china 1. academy of mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China2. School of Information Science and Engineering Graduate University of the Chinese Academy of Sciences Beijing 100190 China3. Department of Mathematics Syracuse University Syracuse NY 13244 USA4. Department of Scientific Computing and Computer Applications Sun Yat-sen University Guangzhou 510275 China

We propose a fully discrete fast Fourier-Galerkin method for solving an integral equation of the first kind with a logarithmic kernel on a smooth open arc,which is a reformulation of the Dirichlet problem of the Laplace equation in the *** optimal convergence order and quasi-linear complexity order of the proposed method are established.A precondition is *** this method with an efficient numerical integration algorithm for computing the single-layer potential defined on an open arc,we obtain the solution of the Dirichlet problem on a smooth open arc in the *** examples are presented to confirm the theoretical estimates and to demonstrate the efficiency and accuracy of the proposed method.

关键词： Dirichlet problem open arc singular boundary integral equations Fourier-Galerkin methods logarithmic potentials

Unlocking iron-based mixed-phosphate cathode for sodium-ion batteries through off-stoichiometry

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Nano Research 2024年第9期17卷 8119-8125页

作者： Zhaolu Liu Yongjie Cao ning Wang Hui Yang Hao Zhang Xinyue xu Nan Wang Jie xu Yao Liu Junxi Zhang Yongyao Xia Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power Shanghai University of Electric PowerShanghai 200090China department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Fudan UniversityShanghai 200433China school of Materials Science and Engineering Anhui University of TechnologyMa’anshan 243002China Key Laboratory of Interfacial Physics and Technology Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghai 201800China

The off-stoichiometric iron-based phosphate(Na_(3.12)Fe_(2.44)(P_(2)O_(7))_(2),denoted as Na3.12)as a low cost and high structure stability cathode material has been widely studied for sodium-ion batteries(SIBs).However,the lower theoretical specific capacity(117 mAh·g^(-1))has seriously limited its practical *** this work,we incorporate varying proportion of sodium-iron phosphate(NaFePO_(4))into the Na3.12 to form a series of new high specific capacity mixed-phosphates Na_(3.12+x)Fe_(2.44+x)(P_(2)O_(7))_(2)(PO_(4))x cathode materials for *** optimizing the introduction amount of NaFePO_(4)into Na_(3.12),the practical reversible of Na_(3.12+x)Fe_(2.44+x)(P_(2)O_(7))_(2)(PO_(4))_(x) increased from 92 to 125.2 mAh·g^(-1).The nano-size Na5.12Fe4.44(P_(2)O_(7))_(2)(PO_(4))_(2) cathode material shows a reversible specific capacity of 125.2 mAh·g^(-1)at 0.1 C in *** at 60 C,it still exhibits a reversible specific capacity of 93.3 mAh·g^(-1)and keeps a capacity retention ratio of 87%after 3000 cycles at 20 ***,we present a novel approach to design a series of off-stoichiometric mixed-phosphates cathode materials for SIBs.

关键词： sodium-ion batteries cathode material iron-based mixed-phosphates off-stoichiometric

On exactness and unbiasedness of confidence bands for a continuous distribution function

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Science china mathematics 2010年第10期53卷 2665-2678页

作者： DING XiaoBo1,2,xu XingZhong2 & ZHAO ShuRan3 1Institute of Applied mathematics,academy of mathematics and Systems Science,chinese academy of sciences,beijing 100190,china 2department of mathematics,beijing Institute of Technology,beijing 100081,china 3school of Economics,Ocean University of china,Qingdao 266071,china 1. Institute of Applied mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China2. Department of Mathematics Beijing Institute of Technology Beijing 100081 China3. School of Economics Ocean University of China Qingdao 266071 China

We define a class of confidence bands for distribution functions,named simple confidence *** class of bands includes the common step bands and continuous bands,some of which may perform better than the smoothed bands not belonging to the class,e.g.,the kernel smoothed *** is shown that under some mild assumptions,the simple bands with exact coverage for continuous distribution functions are all step *** unbiasedness problem of the step bands is also *** is proved that most of two-sided step bands are biased and one-sided step bands are unbiased.

关键词： exact coverage goodness of fit kernel smoothing simple confidence bands unbiasedness

A Note on the Singular Limit of the Exact Controllability of Dissipative Wave Equations

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Acta Mathematica Sinica,English Series 2000年第4期16卷 601-612页

作者： Yuping Tang xu Zhang department of mathematics, Daxian Teacher’s College, Daxian 63500 Sichuan. P. R. china school of mathematics, Sichuan University. Chengdu 610064. Sichuan. P. R. china academy of mathematics and Systems sciences, chinese academy of sciences beijing 100080. P. R. china department of mathematics Daxian Teacher's College Daxian 635000 Sichuan P. R. China school of mathematics Sichuan University Chengdu 610064 Sichuan P. R. China academy of mathematics and Systems sciences Chinese Academy of Sciences Beijing 100080 P. R. China

In this note we analyze the exact controllability of singularly perturbed damped wave equations under more general geometric control condition than that of [1]. We show that the null controllability of the heat equati... 详细信息

关键词： Controllability Singular perturbation Heat equation Wave equation

Study on growth and properties of novel γ-LiAlO_2 substrate

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Science china(Technological sciences) 2006年第2期49卷 188-193页

作者： ZOU Jun1,2, ZHOU Shengming1, xu Jun1 & ZHANG Rong3 1. Shanghai Institute of Optics and Fine Mechanics, chinese academy of sciences, Shanghai 201800, china 2. graduate school of chinese academy of sciences, beijing 100039, china 3. Laboratory of Solid State Microstructures and department of Physics, Nanjing University, Nanjing 210093, china 1. Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China 2. graduate school of chinese academy of sciences Beijing 100039 China 3. Laboratory of Solid State Microstructures and department of Physics Nanjing University Nanjing 210093 China

Transparent γ-LiAlO2 single crystal has been grown by Temperature Gradient technique. The surface of the wafer annealed in O2-atmosphere at 1100°C for 70 h became opaque and Li-poor phase (LiAl5O8); while, that annealed in Li-rich atmosphere kept transparent and smooth. The full-width at half maximum value dropped to 30 arcsecs when the wafer was annealed in Li-rich atmosphere. That annealed in O2-atmosphere increased to 78 arcsec. Compared with absorption spectra, we can conclude that the 196 nm absorption peak was caused by Li vacancies and the 736 nm peak was caused by O vacancies.

关键词： γ-LiAlO2 crystal, scanning electron micrograph (SEM), absorption spectra.

Preparation of Pt/K_2La_2Ti_3O_(10) and its photo-catalytic activity for hydrogen evolution from methanol water solution

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Science china Chemistry 2006年第2期49卷 162-168页

作者： CUI Wenquan1,3, LIU Li2, FENG Liangrong1, xu Chenghua1, LI Zijian1, Lü Shaojie1 & QIU Fali1 1. Chengdu Institute of Organic Chemistry, chinese academy of sciences, Chengdu 610041, china 2. Chemistry department, Sichuan University of Science & Engineering, Zigong 643033, china 3. graduate school of the chinese academy of sciences, beijing 100039, china Correspondence should be addressed to Qiu Fali 1. Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu 610041 China 3. graduate school of the chinese academy of sciences Beijing 100039 China 2. Chemistry department Sichuan University of Science & Engineering Zigong 643033 China

A layered perovskite-type oxide K2La2Ti3O10 was prepared with high-temperature solid-state reaction, and characterized with X-ray diffraction (XRD) and ultraviolet-visible diffuse re-flectance spectroscopy (UV-Vis DRS). Platinum was loaded onto K2La2Ti3O10 as a co-catalyst with different methods. The dispersion of platinum on K2La2Ti3O10 was determined with HOT method. The photocatalytic activity of Pt/K2La2Ti3O10 was studied. This catalyst showed much higher activity in hydrogen evolution reaction than Ni/K2La2Ti3O10. The effects of different amounts of loaded platinum and several preparation methods were evaluated. The best achieved hydrogen evolution rate was 233.88 μmol·h?1 by Pt(2%)/K2La2Ti3O10. A possible band structure and mechanism were discussed based on the results.

关键词： photocatalysis hydrogen platinum K_2La_2Ti_3O_(10) support