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Theoretical Study of the Molecular Electrostatic Potential of C_(50)

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Chinese Journal of Structural Chemistry 2006年第6期25卷 719-723页

作者： WANG dong-Lai SHEN Hong-Tao ZHAI Yu-chun College of Materials and Metallurgy Northeastern University Shenyang 110004 China

Density functional theory （DFT） calculations on three lower energy isomers of C50 were carried out at the B3LYP/6-31G＊ level. Of the three isomers, two have D5h symmetry （a singlet state and a triplet state） and the other one has D3 symmetry. The optimized configurations and electrostatic potential distributions have been obtained. The calculated results show that potential minima Vmin（r） inside the sphere occur at the center of the sphere. The most negative value of the effective Mulliken atomic charge and the largest regions with the most negative MEP outside the sphere are localized in the neighborhood of pentagon-pentagon vertex fusions. They constitute the most probable active sites in chemical reactions. Our results offer a possible explanation for protonation and alkylation of C50 fullerene.

关键词： C50 fullerene electrostatic potential protonation

The Physical-Mechanism Based High-Temperature Thermal Contact Conductance Model with Experimental Verification

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Chinese Physics Letters 2013年第3期30卷 119-122页

作者： LIU dong-Huan SHANG Xin-chun School of Mathematics and Physics University of Science&Technology BeijingBeijing 100083

The physical-mechanism based high-temperature thermal contact conductance model is proposed,in which the temperature effect on the material properties and interface radiation effect are considered.A testing platform of high temperature thermal contact conductance is also established,and the thermal contact conductance between three-dimensional braid C/C composite material and superalloy GH600 is tested under different interface roughness and *** results verify the rationality of the present *** also show that it is necessary to take the effect of temperature into account especially at high temperatures,and the interface radiation effect is negligible compared to spot conduction under 850 K.

关键词： superalloy interface effect

Block dual Toeplitz Operators on the Orthogonal Complements of Fock Spaces

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Acta Mathematica Sinica,English Series 2024年第8期40卷 1967-1988页

作者： Jian Xiang dong chun Xu XU Yu Feng LU School of Mathematical Sciences Dalian University of TechnologyDalian 116024P.R.China School of Mathematics and Information Science Guangzhou UniversityGuangzhou 510006P.R.China

In this paper,we characterize the boundedness and compactness of the block dual Toeplitz operators acting on the orthogonal complement of the Fock spaces,and the compactness of the finite sum of two dual Toeplitz oper... 详细信息

关键词： Block dual Toeplitz operators boundedness compactness Fock space (semi)-commutator

Ground State Solutions for a Class of Choquard Equations Involving Doubly Critical Exponents

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Acta Mathematicae Applicatae Sinica 2021年第4期37卷 820-840页

作者： Yong-yong LI Gui-dong LI chun-lei TANG School of Mathematics and Statistics Southwest UniversityChongqing400715China College of Mathematics and Statistics Northwest Normal UniversityLanzhou730070China

In this paper,we are concerned with the autonomous Choquard equation−Δu+u=(Iα∗|u|^(α/N+1))|u|^(α/N−1)u+|u|^(2∗−2)u+f(u)inR^(N),where N≥3,Iαdenotes the Riesz potential of orderα∈(0,N),the exponentsα/N+1 and 2^(∗)=2N/(N−2)are critical with respect to the Hardy-Littlewood-Sobolev inequality and Sobolev embedding,*** on the variational methods,by using the minimax principles and the Pohožaev manifold method,we prove the existence of ground state solution under some suitable assumptions on the perturbation f.

关键词： choquard equation doubly critical exponents ground state solution

Parametric estimation for the simple linear regression model under moving extremes ranked set sampling design

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Applied Mathematics(A Journal of Chinese Universities) 2021年第2期36卷 269-277页

作者： YAO dong-sen CHEN Wang-xue LONG chun-xian Department of Mathematics and Statistics Jishou UniversityJishou 416000China

Cost effective sampling design is a major concern in some experiments especially when the measurement of the characteristic of interest is costly or painful or time *** set sampling(RSS)was first proposed by McIntyre[1952.A method for unbiased selective sampling,using ranked *** Journal of Agricultural Research 3,385-390]as an effective way to estimate the pasture *** the current paper,a modification of ranked set sampling called moving extremes ranked set sampling(MERSS)is considered for the best linear unbiased estimators(BLUEs)for the simple linear regression *** BLUEs for this model under MERSS are *** BLUEs under MERSS are shown to be markedly more efficient for normal data when compared with the BLUEs under simple random sampling.

关键词： simple linear regression model best linear unbiased estimator simple random sampling ranked set sampling moving extremes ranked set sampling

Numerical investigation of the dynamics of flexible vegetations in turbulent open-channel flows

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Journal of Hydrodynamics 2022年第4期34卷 681-699页

作者： dong Xu Jia-ning Liu Yun-feng Wu chun-ning Ji State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

Aquatic vegetations widely exist in natural rivers and play an essential role in the evolution of the water environment and ecosystem by changing the river’s hydrodynamic characteristics and transporting sediments and *** reality,most aquatic vegetations are highly flexible,which invalidates the“rigid-cylinder”assumption widely adopted in many *** explore the dynamics of submerged flexible vegetation in open-channel flows and its feedback to turbulent flow structures,numerical simulations are carried out using an in-house fluid-structure interaction(FSI)*** the simulations,the geometry of vegetation plants is grid-resolved,the turbulent flow is simulated using the large eddy simulation(LES),the dynamics of the flexible plants are solved using the vector form intrinsic finite element(VFIFE)method,and the turbulent flow and the plants are two-way coupled using the immersed boundary(IB)*** dynamic responses of the flexible vegetation with different plant flexibility,spacing,and submergence are *** results show that flexible plants are subjected to complex flow-induced vibrations(FIVs)rather than static *** FIV involves both streamwise and cross-flow motions driven by the small-scale vortex shedding around the plants and the large-scale Kelvin-Helmholtz(K-H)vortices developed in the vegetation canopy *** vegetations exhibit pulsive wave motion of different patterns in relatively long and narrow open *** with the open-channel flows with static plants with equivalent bending deformation,the dynamic responses of flexible plants may increase the turbulent Reynolds stress of the open-channel flow by 70%–100%and increase the invasion depth of the K-H vortices by 30%–50%.

关键词： Flexible vegetation dynamic responses flow-induced vibration(FIV) fluid-structure interaction(FSI)

Performance Evaluation of Memory-Centric ARMv8 Many-Core Architectures:A Case Study with Phytium 2000+

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Journal of Computer Science & Technology 2021年第1期36卷 33-43页

作者： Jian-Bin Fang Xiang-Ke Liao chun Huang De-Zun dong College of Computer National University of Defense TechnologyChangsha 410073China

This article presents a comprehensive performance evaluation of Phytium 2000+,an ARMv8-based 64-core *** focus on the cache and memory subsystems,analyzing the characteristics that impact the high-performance computing *** provide insights into the memory-relevant performance behaviours of the Phytium 2000+system through *** the help of the well-known roofline model,we analyze the Phytium 2000+system,taking both memory accesses and computations into *** on the knowledge gained from these micro-benchmarks,we evaluate two applications and use them to assess the capabilities of the Phytium 2000+*** results show that the ARMv8-based many-core system is capable of delivering high performance for a wide range of scientific kernels.

关键词： many-core architecture memory-centric design performance evaluation

Characteristics of general distribution of hepatitis B virus genotypes in China

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Hepatobiliary & Pancreatic Diseases International 2009年第4期8卷 397-401页

作者： Zhu, Chang-Tai dong, chun-Lei Suzhou Univ Changzhou Canc Hosp Dept Lab Med Changzhou 213001 Peoples R China

BACKGROUND: Based on differences in the virus nucleotide sequence, hepatitis B virus (HBV) genotypes are presently divided into genotypes A-H. The geographic distributions of HBV genotypes differ in countries and regions. To determine the general characteristics of their distributions in the mainland of China, we reviewed articles on HBV genotypes published in China. METHODS: The Wanfang Database and the CNKI Database were searched for original articles involving HBV in China, and then the data from the articles were classified according to genotype and latitude and analyzed using SPSS 11.0. RESULTS: The main HBV genotypes were C, B and BC, and their rates were 50.99%, 35.58%, 6.07%, respectively; other genotypes were rare. There was a negative correlation between latitude and the rate of genotype B (r=-0.782, P0.05). CONCLUSIONS: In China, HBV genotype C predominates, followed by genotype C and mixed genotype BC; genotypes A, D and others are rare. With an increasing latitude, the distribution of genotype B decreases gradually, while that of genotype C tends to increase. The other genotypes do not show any changes.

关键词： hepatitis B virus genotype chronic hepatitis B

Risk Factors for Diabetes and Cardiovascular Complications in the Chinese Population

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China CDC weekly 2023年第45期5卷 1017-1021页

作者： chun Dou dong Liu Tiange Wang Department of Endocrine and Metabolic Diseases Shanghai Institute of Endocrine and Metabolic DiseasesRuijin HospitalShanghai Jiao Tong University School of MedicineShanghaiChina Shanghai National Clinical Research Center for Metabolic Diseases Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR ChinaShanghai Key Laboratory for Endocrine TumorRuijin HospitalShanghai Jiao Tong University School of MedicineShanghaiChina.

Type 2 diabetes,a major noncommunicable disease,is typified by hyperglycemia,which stems from insulin resistance and dysfunction of pancreaticβ-cells(1).Prior multi-ethnic studies hypothesized that type 2 diabetes among Caucasians was primarily driven by insulin resistance,whereas in East Asians,it was predominantly a consequence ofβ-cell dysfunction(2).Apart from the apparent genetic variations,obesity has been identified as the main factor responsible for the pathophysiological differences in diabetes between Caucasians and East Asians(3).Notably,China has seen a considerable increase in obesity cases in congruence with substantial changes in lifestyle and urbanization over the last four *** a recent population-based national cohort study,we showed that insulin resistance,rather thanβ-cell dysfunction,had a significant role in the pathological progression of diabetes within the Chinese population(1).This correlation was particularly pronounced among obese adults(1).

关键词： obesity sized consequence