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PERMANENCE AND PERIODIC SOLUTION OF NONAUTONOMOUS DELAY LOTKA-VOLTERRA DIFFUSION SYSTEM

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Systems Science and Mathematical Sciences 1999年第4期12卷 344-349页

作者： xiAO Yanni(institute of mathematics, Academia Sinica, beijing 100080, china)WANG Weidong(Deportment of mathematics and Computer Hubei institute for Nationalities, Enshi 445000, china)CHEN Jufang(department of mathematics, Shaanxi Normal University, xi’an 中科院数学所北京 100080 湖北民族学院数学和计算机系湖北恩施 445000 陕西师范大学数学系陕西西安 710062

This paper analyzes permanence, existence and global attractivity of positiveperiodic solution in nonautonomous delay diffusive Lotka-Volterra competitive system fora patchstyle environment, by applying the invariant ... 详细信息

关键词： Permanence ultimately bounded domain diffusion rate periodic solution global attractivity.

Source time-function as discriminant using empirical Green's function

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Science china Earth Sciences 2005年第12期48卷 2118-2122页

作者： HE Yongfeng1,2 & CHEN xiaofei1 1. department of Geophysics, School of Earth & Space Sciences, Peking University, beijing 100871, china 2. North-West institute of Nuclear technology, xi’an 710024, china 1. department of Geophysics School of Earth & Space Sciences Peking University 100871 Beijing China 2. North-West institute of Nuclear technology 710024 Xi’an China

The source mechanism of underground nuclear explosions is remarkably different from that of earthquakes in both spatial radiation pattern and source time-function (STF). Small underground nuclear explosions can be used as empirical Green’s functions (EGF) to isolate the source-time spectrum of a large suspected earthquake occurred in a Nuclear Test Site (target area) by the spectral division method. As this study shows, with high-quality data, the quotient spectrum can be transformed to the time domain, yielding the apparent far-field source-time function of the large suspected event. The relative source time-function (RSTF) of a nuclear ex-plosion is usually a simple pulse with a duration of about 1 s., while an earthquake’s is more complicated with a series of pulses and a longer duration. The RSTF can be used as a nice dis-criminant to distinguish the nature earthquakes from underground nuclear explosions in target areas.

关键词： target-area, empirical Green's function, RSTF.

Transforming liquid flow fuel cells to controllable reactors for highlyefficient oxidation of 5-hydroxymethylfurfural to 2, 5-furandicarboxylic acid at low temperature

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Journal of Energy Chemistry 2024年第3期90卷 621-631,I0014页

作者： Ye Qiang xi Liu Denghao Ouyang Zhao Jiang Xuebing Zhao Key Laboratory of Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084China institute of Applied Chemistry Department of Chemical EngineeringTsinghua UniversityBeijing 100084China School of Chemical Engineering and technology Xi'an Jiaotong UniversityXi'an 710049ShaanxiChina

Highly-efficient oxidation of 5-hydroxymethylfurtural(HMF) to 2,5-furandicarboxylic acid(FDCA) at low temperature with air as the oxidant is still ***,inspired by the respirato ry electron transport chain(ETC) of living cells mediated by electron carriers,we constructed artificial ETCs and transformed liquid flow fuel cells(LFFCs) to flexible reactors for efficient oxidation of HMF to produce FDCA under mild *** LFFC reactor employed an electrodeposition modified nickel foam as an anode to promote HMF oxidation and(VO_(2))_(2)SO_(4) as a cathode electron carrier to facilitate the electron transfer to *** reaction rate could be easily controlled by selecting the anode catalyst,adjusting the external loading and changing the cathodic electron carrier or oxidants.A maximal power density of 44.9 mW cm^(-2) at room temperature was achieved,while for FDCA production,short-circuit condition was preferred to achieve quick transfer of *** a single batch operation with 0.1 M initial HMF,FDCA yield reached 97.1%.By fed-batch operation,FDCA concentration reached 144.5 g L^(-1) with a total yield of 96%.Ni^(2+)/Ni^(3+) redox couple was the active species mediating the electron transfer,while both experimental and DFT calculation results indicated that HMFCA pathway was the preferred reaction mechanism.

关键词： 5-Hydroxymethylfurfural 2 5-Furandicarboxylic acid Electrodeposition Electron transport chain Liquid flow fuel cell

A NOTE ON THE SPECTRUM OF NEUTRON TRANSPORT OPERATOR IN A SLAB WITH GENERALIZED BOUNDARY CONDITIONS

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Systems Science and Mathematical Sciences 1992年第2期5卷 97-107页

作者： SONG Degong WANG Miansen (department of mathematics,xi’an Jiaotong University,xi’an 710049,china)ZHU Guangtian (institute of Systems Science,Academia Sinica,beijing 100080,china)

The spectrum of neutron transport operator A in an arbitrary non-homogeneous slab geometry is discussed in consideration of anisotropic scatteringand *** the assumptions that the boundary reflection coefficient func-tion α（v,μ）,γ（v,μ）and the scattering-fission kernel k（x,v,v′,μ,μ′）are boundedmeasurable,and the total collision frequency v∑（x,v）is square integrable,it isshown that A has at most finite spectrum points in any strip{λ=β+i（?）|β1（?）β（?）β2},where β2>β1>-λ*,with λ* the essential infimum of v∑（x,v）.Fi-nally,the asymptotic expansion of the solution for the time-dependent equation（dN）/（dt）=AN,N（0）=N0 is given as a corollary.

关键词： Neutron transport operator slab geometry generalized boundary conditions spectrum asymptotic expansion

On triangular algebras with noncommutative diagonals

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Science china mathematics 2008年第10期51卷 1937-1944页

作者： DONG AiJu department of mathematics, xi’an University of Arts and Science, xi’an 710065, china institute of mathematics Zhejiang Sci-Tech University Hangzhou 310018 China department of mathematics Statistics and Computer Science St. Francis Xavier University Antigonish Nova Scotia Canada B2G 2W5

We construct a triangular algebra whose diagonals form a noncommutative algebra and its lattice of invariant projections contains only two nontrivial projections. Moreover we prove that our triangular algebra is maximal.

关键词： triangular algebra von Neumann algebra reflexive algebra reflexive lattice 47L75 46L10

Electrochemical reduction of carbon dioxide to produce formic acid coupled with oxidative conversion of biomass

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Journal of Energy Chemistry 2024年第5期92卷 705-729页

作者： xi Liu Yifan Wang Zhiwei Dai Daihong Gao Xuebing Zhao Key Laboratory of Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084China institute of Applied Chemistry Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

Electrochemical reduction of CO_(2)(CO_(2)RR)has become a research hot spot in recent years in the context of carbon *** is one of the most promising products obtained by electrochemical reduction of CO_(2) due to its high energy value as estimated by market price per energy unit and wide application in chemical *** is the most abundant renewable resource in the natural *** biomass oxidative conversion with CO_(2)RR driven by renewable electricity would well achieve carbon *** this work,we comprehensively reviewed the current research progress on CO_(2)RR to produce HCOOH and coupled system for conversion of biomass and its derivatives to produce value-added ***-and Bi-based electrocatalysts are discussed for CO_(2)RR with regards to the structure of the catalyst and reaction ***-oxidation reactions of biomass derived sugars,alcohols,furan aldehydes and even polymeric components of lignocellulose were reviewed as alternatives to replace oxygen evolution reaction(OER)in the conventional electrolysis *** was recommended that to further improve the efficiency of the coupled system,future work should be focused on the development of more efficient and stable catalysts,careful design of the electrolytic cells for improving the mass transfer and development of environment-friendly processes for recovering the formed formate and biomass oxidation products.

关键词： Electrochemical reduction of CO_(2) Formic acid Oxidative conversion of biomass Lignocellulose Coupled system

Liquid metal biomaterials: translational medicines,challenges and perspectives

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National Science Review 2024年第2期11卷 264-284页

作者： Hanchi Xu Jincheng Lu Yikuang xi Xuelin Wang Jing Liu department of Biomedical Engineering School of Medicine Tsinghua University beijing Tsinghua Changgung Hospital School of Clinical Medicine Tsinghua University Shanghai World Foreign Language Academy beijing Advanced Innovation Center for Biomedical Engineering School of Engineering MedicineBeihang University beijing Key Lab of Cryo-Biomedical Engineering and Key Lab of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences

Until now, significant healthcare challenges and growing urgent clinical requirements remain incompletely addressed by presently available biomedical materials. This is due to their inadequate mechanical compatibility, suboptimal physical and chemical properties, susceptibility to immune rejection, and concerns about long-term biological safety. As an alternative, liquid metal(LM) opens up a promising class of biomaterials with unique advantages like biocompatibility, flexibility, excellent electrical conductivity,and ease of functionalization. However, despite the unique advantages and successful explorations of LM in biomedical fields, widespread clinical translations and applications of LM-based medical products remain limited. This article summarizes the current status and future prospects of LM biomaterials, interprets their applications in healthcare, medical imaging, bone repair, nerve interface, and tumor therapy, *** to translate LM materials into medicine and obstacles encountered in practices are *** that, we outline a blueprint for LM clinics, emphasizing their potential in making new-generation artificial organs. Last, the core challenges of LM biomaterials in clinical translation, including bio-safety,material stability, and ethical concerns are also discussed. Overall, the current progress, translational medicine bottlenecks, and perspectives of LM biomaterials signify their immense potential to drive future medical breakthroughs and thus open up novel avenues for upcoming clinical practices.

关键词： liquid metal biomaterials translational medicine clinical device healthcare therapeutics

RECRYSTALLIZATION OF SWAGED W-Ni-Fe HEAVY ALLOY DURING ANNEALING TREATMENT

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Acta Metallurgica Sinica(English Letters) 1996年第5期9卷 355-360页

作者： Z. Li Y.L. Yand J.K xi J.X. Qu and H. S. Shao (department of Materials Engineering, Luoyang institute of technology, Luoyang 471039, china)(beijing Graduate School, china University of Mining and technology, beijing 100083, china)

Annealing treatment has a strong effect on mechanical Properties of cold worked tungsten-nickel-iron heavy alloys. A 93W-4.5Ni-2.5Fe alloy swaged 15% was annealed from 500 to 1350℃ to investigate the changes in microstructure and their effects on mechanical properties. Recrystallization of W particles takes place during annealing treatments above 800℃ and the microhardnesses reduces rapidly. High density of dislocations in the, matrix phase after annealing treatment at 1350℃ suggests that recrystallization of the matrix phase has not taken place. A small decrease in microhardness of the matrix phase is caused by recovery during the annealing *** changes in mechanical properties of swaged and annealed 93W-4.5 *** alloy are mainly due to the changes in microstructure of W particles because of their recrystallization.

关键词： W-4.5 Ni-2. 5 Fe alloy recrystallization dislocation

Molecular cloning and functional analysis of two calcium associated cuticular protein genes in Neocaridina denticulata sinensis

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Journal of Oceanology and Limnology 2024年第5期42卷 1659-1672页

作者： xi GAO Mengmeng DUAN Yuying SUN Jiquan ZHANG School of Life Sciences/Hebei Basic Science Center for Biotic Interaction Hebei UniversityBaoding 071002China institute of Life Science and Green Development Hebei UniversityBaoding 071002China

The body surface of crustaceans is covered with a sturdy *** growth and development of crustaceans are realized through *** denticulata sinensis is a suitable candidate for crustacean scientific *** calcium-associated cuticular protein genes,named NdCAP-1 and NdCAP-2,were obtained from *** *** docking simulated the binding effect of both proteins and calcium ***-quantitative reverse transcription PCR results show that NdCAP-1 is expressed in D_(2-4) stage,NdCAP-2 expressed in D_(2-4) and A-B stages,and both were significantly expressed in the cephalothorax cuticle and ***,it was revealed that NdCAP-1 and NdCAP-2 are regulated by NdEcR-mediated 20 E signaling *** of NdCAP-1 and NdCAP-2 was observed to cause surface *** recombinant proteins(rNdCAP-1 and rNdCAP-2),obtained by prokaryotic expression,had calcium-binding and chitin-binding ability,inhibited formation of calcium carbonate *** results show that calcium-associated cuticular proteins play important roles in cuticle formation and calcification.

关键词： Neocaridina denticulata sinensis calcium-associated cuticular protein molting cycle RNAi calcium-binding ability