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Density-functional formula for strongly correlated systems

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Progress in Natural Science:Materials International 2005年第5期15卷 395-401页

作者： WANG Huaiyu1*, han Rushan2.and {2. Nanxian1(1. department of {2., Tsinghua university, Beijing 100084, china 2. department of {2., Peking university, Beijing 100871, china) department of physics Tsinghua University Beijing 100084 China department of physics Peking University Beijing 100871 China

Density functional method is applied for strongly correlated systems. Based on the assumption that the systems are composed of electrons in singly-occupied orbitals and those in doubly-occupied orbitals, a set of self-consistent equations are obtained by standard variation procedure. The equations consist of two parts. One part is to solve the wave functions of the electrons in singly-occupied orbitals and the other is to solve the wave functions of the electrons in doubly-occupied orbitals. The physical meanings of the terms appearing in the equations are discussed.

关键词： density-functional theory strongly correlated systems doubly-occupied orbital two-particle wave function self-consistent equations.

Linearly time-varying channel estimation and training power allocation for OFDM/MIMO systems using superimposed training

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Science china(Information Sciences) 2011年第7期54卷 1456-1470页

作者： ZhanG han 1,DAI XianHua 2.& Pan DaRu 1 1 School of {2. and Telecommunication Engineering,south {2. Normal university,guangzhou 510006,{2. 2.department of Information Science and technology,SUN Yat-sen university,guangzhou 51002.,{2. School of physics and Telecommunication Engineering South China Normal University department of Information Science and technology SUN Yat-sen University

We address the problem of estimating the linearly time-varying (LTV) channel of orthogonal frequency division multiplexing (OFDM)/multiple-input multiple-output (MIMO) systems using superimposed training (ST).The LTV channel is modeled by truncated discrete Fourier *** on this model,a two-step approach is adopted to estimate the LTV channel over multiple OFDM *** also present performance analysis of the channel estimation and derive a closed-form expression for the channel estimation *** is shown that the estimation variances,unlike that of the conventional ST-based schemes,approach to a fixed lower-bound as the training length increases,which is directly proportional to information-pilot power *** wireless communication systems with a limited transmission power,we optimize the ST power allocation by maximizing the lower bound of the average channel *** results show that the proposed approach outperforms the frequency-division multiplexed training schemes.

关键词： OFDM/MIMO systems linearly time-varying channel estimation superimposed training training power allocation

Properties of Rotating Neutron Stars in the Relativistic σ-ω Model

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Communications in Theoretical physics 2004年第1期41卷 51-54页

作者： WEN De-Hua~(1,2. chen Wei~3 WANG Xian-Ju~1 AI Bao-Quan~1 LIU Guo-Tao~1 LIU Liang-Gang~1 1 department of {2.,Zhongshan university,guangzhou 5102.5,china2.department of {2.,south china university of technology,guangzhou 510641,china3 department of {2.,Jinan university,guangzhou 510632.china department of physics Zhongshan University Guangzhou 510275 China

The properties such as the moment of inertia,the surface redshift and the radius of gyration of rotatingneutron stars in the relativistic σ-ω model are studied with the Hartle’s *** relation between the angularvelocity of the fluid relative to the local inertial frame and the uniform angular velocity relative to the infinite iscalculated.

关键词： relativistic σ-ω model rotating neutron star equation of state

Association of physical activity with risk of chronic kidney disease in china:A population-based cohort study

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Journal of Sport and Health Science 2024年第2期13卷 204-211页

作者： Kexiang Shi Yunqing Zhu Jun Lv Dianjianyi Sun Pei Pei Huaidong Du Yiping chen Ling Yang Bing han Rebecca Stevens Junshi chen Zhengming chen Liming Li Canqing Yu china Kadoorie Biobank collaborative group department of Epidemiology&Biostatistics School of Public HealthPeking University Health Science CenterBeijing 100191China Peking university Center for Public Health and Epidemic Preparedness&Response Beijing 100191China Key Laboratory of Epidemiology of Major Diseases(Peking university) Ministry of EducationBeijing 100191China Clinical Trial Service Unit&Epidemiological Studies Unit(CTSU) Nuffield Department of Population HealthUniversity of OxfordOxford OX37LFUK Medical Research Council Population Health Research Unit at the university of Oxford Oxford OX37LFUK NCDs Prevention and Control department Henan Center for Disease Control and PreventionZhengzhou 450016China china National Center for Food Safety Risk Assessment Beijing 100022China 不详

Background:Information on the association between physical activity(PA)and the risk of chronic kidney disease(CKD)is *** aimed to explore the associations of total,domain-specific,and intensity-specific PA with CKD and its subtypes in ***:The study included 475,376 adults from the china Kadoorie Biobank aged 30-79 years during 2.04-2.08 at *** interviewer-administered questionnaire was used to collect the information about PA,which was quantified as metabolic equivalent of task hours per day(MET-h/day)and categorized into 4 groups based on *** regression was used to analyze the association between PA and CKD ***:During a median follow-up of 12.1 years,5415 incident CKD cases were documented,including 1159 incident diabetic kidney disease(DKD)cases and 362.incident hypertensive nephropathy(HTN)*** PA was inversely associated with CKD risk,with an adjusted hazard ratio(HR,95%confidence interval(95%CI))of 0.83(0.75-0.92.for incident CKD in the highest quartile of total PA as compared with participants in the lowest *** results were observed for risk of DKD and HTN,and the corresponding HRs(95%CIs)were 0.75(0.58-0.97)for DKD risk and 0.56(0.37-0.85)for HTN *** nonoccupational PA,low-intensity PA,and moderate-to-vigorous-intensity PA were significantly associated with a decreased risk of CKD,with HRs(95%CIs)of 0.80(0.73-0.88),0.85(0.77-0.94),and 0.85(0.76-0.95)in the highest quartile,***:PA,including nonoccupational PA,low-intensity PA,and moderate-to-vigorous-intensity PA,was inversely associated with the risk of CKD,including DKD,HTN,and other CKD,and such associations were dose dependent.

关键词： Chronic kidney disease Domain Intensity Physical activity

Dimension and measure theoretic entropy of a subshift in symbolic space

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Chinese Science Bulletin 1997年第14期42卷 1193-1196页

作者： chen Ercai and XIONG Jincheng1. {2. of Astronomy, Nanjing university, Nangjing 2.0093, china 2. {2. of Mathematics, south china Normal university, guangzhou 510631, china department of Astronomy Nanjing University Nangjing China department of Mathematics South China Normal University Guangzhou China

1 Definitions and resultsWITH the development of the theory of dynamical systems and fractal geometry, one provedthat symbolic dynamics is a powerful tool to study chaos and fractals. It is useful to study thefractal characteristics of symbolic dynamics. In the present note we shall point out the relationbetween the dimension and measure theoretic entropy of any subshift in symbolic space. Weprove here that the Bowen’s formula for Hausdorff dimension holds without Markov struc-ture. A variational principle for dimension is obtained.

关键词： symbolic space subshift measure theoretic entropy dimension.

Rock mass quality prediction on tunnel faces with incomplete multi-source dataset via tree-augmented naive Bayesian network

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International Journal of Mining Science and technology 2024年第3期34卷 323-337页

作者： Hongwei Huang chen Wu Mingliang Zhou Jiayao chen Tianze {2. Le Z{2.g Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China department of Geotechnical Engineering Tongji UniversityShanghai 200092China School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China Qingdao Guoxin Second Jiaozhou Bay Subsea Tunnel Co. Ltd.Qingdao 266071China

Rock mass quality serves as a vital index for predicting the stability and safety status of rock tunnel *** tunneling practice,the rock mass quality is often assessed via a combination of qualitative and quantitative ***,due to the harsh on-site construction conditions,it is rather difficult to obtain some of the evaluation parameters which are essential for the rock mass quality *** this study,a novel improved Swin Transformer is proposed to detect,segment,and quantify rock mass characteristic parameters such as water leakage,fractures,weak *** site experiment results demonstrate that the improved Swin Transformer achieves optimal segmentation results and achieving accuracies of 92.,81%,and 86%for water leakage,fractures,and weak interlayers,respectively.A multisource rock tunnel face characteristic(RTFC)dataset includes 11 parameters for predicting rock mass quality is *** the limitations in predictive performance of incomplete evaluation parameters exist in this dataset,a novel tree-augmented naive Bayesian network(BN)is proposed to address the challenge of the incomplete dataset and achieved a prediction accuracy of 88%.In comparison with other commonly used Machine Learning models the proposed BN-based approach proved an improved performance on predicting the rock mass quality with the incomplete *** utilizing the established BN,a further sensitivity analysis is conducted to quantitatively evaluate the importance of the various parameters,results indicate that the rock strength and fractures parameter exert the most significant influence on rock mass quality.

关键词： Rock mass quality Tunnel faces Incomplete multi-source dataset Improved Swin Transformer Bayesian networks

Cu_(2.Se@C thin film with three-dimensional braided structure as a cathode material for enhanced Cu^(2.) storage

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Chinese Chemical Letters 2024年第5期35卷 523-528页

作者： Wenhao chen Muxuan Wu han chen Lue Mo Yirong Zhu College of Materials and Advanced Manufacturing Hunan University of TechnologyZhuzhou 412007China Hunan Key of Laboratory of Applied Environmental Photocatalysis Changsha UniversityChangsha 410022China

In the face of multiple challenges brought by the changes of global climate and environment,developing clean energy and updating green energy storage equipment are important ways to achieve carbon peak and carbon *** batteries have become a research hotspot due to their advantages of using the multivalent charge carrier,high ionic conductivity,environmental friendliness and cost *** this work,the Cu_(2.Se@C(Cu_(2.Se coated on carbon clothes)thin film with a three-dimensional braided structure is fabricated by a simple electrochemical deposition method for Cu^(2.)storage for the first *** with the commercial Cu_(2.Se powder,the well-designed Cu_(2.Se@C film shows enhanced specific capacity(640 mAh/g at 0.5 A/g)and rate performance(542.mAh/g at 5 A/g)as well as superior cycling stability(82.7%capacity retention after 1000 cycles at 1 A/g).The Cu^(2.)storage mechanism of the Cu_(2.Se@C electrode is based on a reversible phase transition process of Cu_(2.Se←→Cu_(2.x)Se←→CuSe←→CuSe_(2..In kinetic characteristic analysis,the Cu_(2.Se@C electrode demonstrates faster Cu^(2.)diffusion in discharge process than charge process resulting from the phase transition and the variation of interplanar *** work highlights a facile one-piece design strategy and opens a new gateway for the exploration of advanced aqueous energy storage systems.

关键词： Cu_(2.Se@C Cu^(2.)storage Conversion mechanism Kinetic characteristic Flexible energy storage

Variation of the Fe/Mn ratio of ferromanganese crusts from the Central North Pacific: implication for paleoclimate changes

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Progress in Natural Science:Materials International 2005年第6期15卷 530-537页

作者： LU Zunli1**, LING Hongfei1*, ZHOU Feng1, JIANG Shaoyong1, chen Xiaoming1 and ZHOU Huaiyang2.1. State Key Laboratory for Mineral Deposits Research, {2. of Earth Sciences, Nanjing {2., Nanjing 2.0093, china 2. guangzhou Institute of Geochemistry, Chinese Academy of Sciences, guangzhou 510640, china){2. of Earth & Environmental Science, {2. of Rochester State Key Laboratory for Mineral Deposits Research Department of Earth Sciences Nanjing University Nanjing 210093 China department of Earth & Environmental Science University of Rochester guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

Contents of Fe, Mn and other elements in four ferromanganese crusts recovered from the central North Pacific are analyzed at high depth-resolution by electron microprobe for reconstructing factors controlling their deposition. Manganese (IV) in hydrogenetic ferromanganese crusts is mainly supplied as colloidal precipitates from the Oxygen Minimum Zone (OMZ), which concentrates high amounts of dissolved Mn (II). The iron is derived from carbonate dissolution and silicate particles of eolian dust. An increase in paleoproductivity during cooler climate would potentially lead to a decrease in Mn deposition due to enlargement of the OMZ which has a “temporary storage” effect for Mn. On the other hand, not affected by the OMZ, the iron entering the Fe-Mn crust would likely increase with the eolian dust input and surface productivity at glacial stages. As a result, the increasing Fe/Mn ratio should indicate a cooling climate. This is supported by the following observations. In the profile of the past 1 Ma, the variations of Fe/Mn ratio coincide with benthic oxygen isotope fluctuation in glacial-interglacial cycles. Three episodes with high Fe/Mn ratios, approximately at 2.6, 1.8 and 0.8 Ma, are detected within the past 3 Ma and coincide with major climate transitions and cooling events. The secular evolution pattern of Fe/Mn ratio in the Cenozoic is similar to the Pb isotope evolution which is mainly controlled by eolian dust and related to climate. The Fe/Mn evolution pattern is also broadly consistent with the global deep-sea oxygen isotope records. Therefore, Fe/Mn ratio recorded in the ferromanganese crusts may be a new proxy for climate change.

关键词： Fe/Mn ratio ferromanganese crust central North Pacific paleoclimate.

On the Existence of Nontrivial Solutions of Quasi-asymptotically Linear Problem for the P-Laplacian

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Acta Mathematicae Applicatae Sinica 2002年第4期18卷 599-606页

作者： Zhi-hui chen, Yao-tian Shendepartment of Applied Mathematics, {2., guangzhou 510640, china department of Applied Mathematics South China University of Technology Guangzhou China

In this paper, we study the existence of nontrivial solutions for the following Dirichlet problem for the p-Laplacian (p > 1):where Ω is a bounded domain in Rn (A≥1) and f(x,u) is quasi-asymptotically linear with respect to |u|p-2.u at infinity. Recently it was proved that the above problem has a positive solution under the condition that f(x, s)/sp-1 is nondecrcasing with respect to s for all x ∈Ω and some others. In this paper. by improving the methods in the literature, we prove that the functional corresponding to the above problem still satisfies a weakened version of (P.S.) condition even if f(x, s)/sp-1 isn't a nondecreasing function with respect to s, and then the above problem has a nontrivial weak solution by Mountain Pass Theorem.

关键词： Quasi-asymptotically linear weak solution critical point Palais-Smale type condition