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The Approximation Properties Determined by Operator Ideals

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Acta Mathematica Sinica,English Series 2017年第3期33卷 311-326页

作者： dong Yang chen Lei LI School of Mathematical Sciences Xiamen University School of Mathematical Sciences and LPMC Nankai University

We introduce the notion of the right approximation property with respect to an operator ideal A and solve the duality problem for the approximation property with respect to an operator ideal ,4, that is, a Banach space X has the approximation property with respect to Ad whenever X＊ has the right approximation property with respect to an operator ideal A. The notions of the left bounded approximation property and the left weak bounded approximation property for a Banach operator ideal are introduced and new symmetric results are obtained. Finally, the notions of the p-compact sets and the p-approximation property are extended to arbitrary Banach operator ideals. Known results of the approximation property with respect to an operator ideal and the p-approximation property are generalized.

关键词： Approximation property operator ideals bounded approximation property A-p-compactsets

Quantitative Characterizations of Bounded Compact Approximation Property by Semi-Fredholm Operators

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Acta Mathematica Sinica,English Series 2023年第6期39卷 1115-1128页

作者： dong Yang chen Ying Bin RUAN School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China School of Mathematics and Statistics Fujian Normal UniversityFuzhou 350007P.R.China

Based on a characterization of upper semi-Fredholm operators due to *** and ***,we introduce and investigate a new quantity characterizing upper semi-Fredholm *** quantity and several well-known quantities are used to characterize bounded compact approximation ***,a new quantity characterizing lower semi-Fredholm operators is introduced,investigated and used to characterize the bounded compact approximation property for dual spaces.

关键词： Bounded compact approximation property compact operators upper semi-Fredholm operators lower semi-Fredholm operators

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Mutual Neutralization of Na^(+)/O^(-) Ions in Slow Collisions

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Chinese Physics Letters 1996年第2期13卷 93-96页

作者： ZHOU Xiao-xin dong chen-zhong Department of Physics Northwest Normal UniversityLanzhou 730070

The mutual neutralization cross sections of Na^(+)/O^(-) ions at low energy have been calculated by using the multichannel LandaZener *** asymptotic method is used for estimating tBe coupling matrix elements between tbe ionic and covalent states at the crossing points of diabatic potential *** results of calculation are compared with available experimental data.

关键词： theory. mutual asymptotic

Psychrotolerant methanogenic archaea:Diversity and cold adaptation mechanisms

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Science China(Life Sciences) 2012年第5期55卷 415-421页

作者： dong XiuZhu chen ZiJuan State Key Laboratory of Microbial Resources Institute of Microbiology Chinese Academy of Sciences Beijing 100101 China

Because of their diversity and abundance in a wide range of environments, particularly in cold regions, cold-adaptive archaea are expected to play a pivotal role in material recycling in cold environments. Methanogenic archaea are ubiquitous on earth and produce a large amount of methane （CH4） as their main carbon metabolite. Methanogens are the most laboratory amenda- ble archaea. The few psychrophilic archaea that have been cultured to date are mainly affiliated with methanogens, thus make them a good model for investigating mechanisms of archaeal cold adaptation. Studies of psychrotolerant methanogens have been ongoing since the 1990s. Using Methanocoecoides burtonii, a methanogen isolated from Ace Lake in Antarctica, exten- sive studies on the genomic characteristics associated with cold adaptation have been carried out by the Cavicchioli laboratory. We recently analyzed the genome of another psychrophilic methanogen and identified the gene repertoire associated with cold adaptation. This review summarizes recent studies of psychroactive methanogens, particularly their diversity, the genomics and proteomics associated with their cold adaptation, and the cellular components and proteins likely involved in their cold protec- tion.

关键词： psychrotolerant methanogens diversity cold adaptation mechanisms

Zooming on T cells in cancer

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Science China(Life Sciences) 2022年第7期65卷 1466-1468页

作者： Xinyi Guo chen dong Institute for Immunology and School of Medicine Tsinghua UniversityBeijing 100084China Shanghai Immune Therapy Institute Shanghai Jiaotong University School of Medicine-affiliated Renji HospitalShanghai 200127China

Immunotherapies have had tremendous progress in treating numerous cancer types since the late twentieth century(Waldman et al.,2020).Accompanied with this,there has been an unprecedented wave of understanding the dynamic changes and the functional mechanisms of immune cells that are tumor-infiltrating and systematically circulating in cancer patients(Waldman et al.,2020).

关键词： al. cancer infiltrating

Degree Conditions on Copies of Forests in Graphs

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Journal of the Operations Research Society of China 2023年第3期11卷 667-672页

作者： Xiao-dong chen Shuai-Jun chen Ming-Chu Li School of Mathematics Liaoning Normal UniversityDalian116029LiaoningChina College of Science Liaoning University of TechnologyJinzhou121001LiaoningChina School of Softsware Dalian University of TechnologyDalian116024LiaoningChina

For a graph G,letμ(G)=min{max{d(x),d(y)}:x≠y,xy∉E(G),x,y∈V(G)}if G is non-complete,otherwise,μ(G)=+∞.For a given positive number s,we call that a graph G satisfies Fan-type conditions ifμ(G)≥***μ(G)≥s,then a vertex v is called a small vertex if the degree of v in G is less than *** this paper,we prove that for a forest F with m edges,if G is a graph of order n≥|F|andμ(G)≥m with at most max{n−2m,0}small vertices,then G contains a copy of *** also give examples to illustrate both the bounds in our result are best possible.

关键词： Fan-type conditions Forest Copy Small vertex

General Decay for a Thermoelastic Problem of a Microbeam with Gurtin-Pipkin Thermal Law

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Acta Mathematicae Applicatae Sinica 2022年第2期38卷 426-440页

作者： dong-qin chen Wen-jun LIU Zhi-jing chen School of Mathematics and Statistics Nanjing University of Information Science and TechnologyNanjing 210044China

In this paper,we study the well-posedness and the asymptotic stability of a one-dimensional thermoelastic microbeam system,where the heat conduction is given by Gurtin-Pipkin thermal *** first establish the well-posedness of the system by using the semigroup arguments and Lumer-Phillips *** then obtain an explicit and general formula for the energy decay rates through perturbed energy method and some properties of the convex functions.

关键词： microbeam system Gurtin-Pipkin thermal law well-posedness general decay

Theoretical Study on Mechanism of Reaction of OH with HO2NO2

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Chinese Journal of Chemical Physics 2008年第1期21卷 32-38页

作者： Yan Tian Tian-jing He Li He Fan-chen Liu dong-ming chen Department of Chemical Physics University of Science and Technology of China Hefei 230026 China Department of Electronic Science and Technology University of Science and Technology of ChinaHefei 230025 China School of Science Anhui Agricultural University Hefei 230036 China

The reaction of HO2NO2 （peroxynitric acid, PNA） with OH was studied by the hybrid density functional B3LYP and CBS-QB3 methods. Based on the calculated potential energy surface, five reaction channels, H20＋NO2＋O2, HOOH＋NO3, NO2＋HO3H, HO2＋HONO2 and HO2＋HOONO, were examined in detail. The major reaction channel is PNA＋OH→M1→TS1→H2O＋NO2＋O2. Taking a pre-equilibrium approximation and using the CBS-QB3 energies, the theoretical rate constant of this channel was calculated as 1.13×10-12 cm^3/（molecule s） at 300 K, in agreement with the experimental result. Comparison between reactions of HOONO2＋OH and HONO2＋OH was carried out. For HOR＋OH reactions, the total rate constants increase from R=NO2 to R=ONO2, which is consistent with experimental measurements.

关键词： Reaction Peroxynitric acid ab initio calculation Rate constant

Modeling sintering behavior of metal fibers with different fiber angles

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Rare Metals 2018年第10期37卷 886-893页

作者： dong-dong chen Zhou-Shun Zheng Jian-Zhong Wang Hui-Ping Tang School of Mathematics and Statistics Central South University State Key Laboratory of Porous Metal Materials Northwest Institute for Nonferrous Metal Research

The formation of sintering necks between two metal fibers was investigated using the oval-oval model with respect to the fiber angle range of 0°-90°. Surface diffusion was assumed to be the predominant mechanism in every section of the junction of two metal fibers in this model, which was addressed numerically using the level- set method. The growth rates of the sintering necks in the direction of the bisector of obtuse angle, the bisector of acute angle and the fiber axis were discussed in detail. It is found that the growth rate of the sintering necks decreases with fiber angle increasing in the direction of the fiber axis and the bisector of acute angle. However, an opposite variation in growth rate of sintering necks can be found in the direction of the bisector of obtuse angle. The numerical simulation results show that the growth rate of the sintering necks is significantly affected by the initial local geomet- rical structure which is determined by the fiber angle.

关键词： Metal fiber Surface diffusion Fiber angle Initial local geometrical structure Initial evolution speed