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Journal of systems science and systems Engineering 2001年第3期13卷 315-322页

作者： ZHANG Jun-hua, fang Wei-wu institute of applied mathematics, academy of mathematics and System sciences, chinese academy of sciences, beijing 100080, China institute of applied mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 China

In this paper, a new statistic is proposed for variable selection which is one of the important problems in analysis of questionnaire data. Contrasting to other methods, the approach introduced here can be used not on... 详细信息

关键词： questionnaire variable selection information divergence statistic

On Size of Unicycle Hypergraphs

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systems science and systems Engineering 2000年第2期10卷 245-250页

作者： LI Hai\|zhu,\ WANG Jian\|fang institute of applied mathematics, chinese academy of sciences, beijing 100080, China

Cyclic hypergraphs are the analogue of cyclic graphs. The unicycle hypergraph whose cyclomatic number equals to one is the most elemental cyclic hypergraph. In this paper the maximum size of unicycle hypergraphs is s... 详细信息

关键词： hypergraph unicycle hypergraph maximum size

On the Measurement of Technological Change

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systems science and systems Engineering 1994年第4期4卷 298-303页

作者： ZHOU fang(The institute of Quantitative & Technical Economics,chinese academy of Social science,Jiangoumennei St.No.5,beijing 100732,China)

A decomposition into components of the overall technological change is carried *** overall technological change is decomposed into the technological change,which consists of autonomous shift and shape-deformation in isoquants of production function over table,the scale economics or diseconomies,and the technological change,which is determined by marginal rates of substitution of factors,capital/labor ratio(capital intensity)and its *** the assumption of constant returns to scale the mathematical framework reduces exactly to Solow’s framework. The mathematical formula derived can be applied to measuring the overall technological change in its components.

关键词： economic growth technological change.

An axisymmetric characteristic model for enhancing prediction of centrifugal compressor characteristics

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chinese Journal of Aeronautics 2024年第4期37卷 203-215页

作者： Peng REN Xiangjun fang Zeyu JIAO Ying HAN School of Energy and Power Engineering Beihang UniversityBeijing 100191China Guangdong Key Laboratory of Modern Control Technology Institute of Intelligent ManufacturingGuangdong Academy of SciencesGuangzhou 510070China

Rapid and accurate determination of compressor characteristic maps is essential for the initial design of centrifugal compressors in aircraft power systems. The accuracy of existing methodologies, which rely on combinations of loss models, varies significantly depending on the compressor's geometry and operational range. This variance necessitates substantial experimental or Computational Fluid Dynamics(CFD) data for coefficient calibration. To address this challenge, this study presents an axisymmetric characteristic model for compressor performance assessment. This model incorporates the factors of blade angle, meridional passage area, and the radial deflection angle of meridional streamlines of the compressor. These factors are derived from fundamental aerodynamic equations encompassing mass, momentum, and energy conservation of the compressor. In contrast to conventional one-dimensional approaches, the proposed method reduces the number of loss coefficients and more effectively accounts for the impact of geometric alterations on centrifugal compressor properties. Furthermore, the model reduces dependence on experimental and CFD data. Efficacy of the model is validated using experimental data from four distinct types of centrifugal compressors. Correlation analysis reveals that the model's coefficients can be expressed as functions of the ratio of the Reynolds number to the impeller tip speed. This ratio serves as a characteristic parameter for the design and optimization of centrifugal compressors. Consequently, the proposed method offers an efficient and accurate means for the quick computation of centrifugal compressor characteristics. This is of great significance for improving the efficiency of centrifugal compressors and reducing energy consumption.

关键词： Centrifugal compressor Positive problem Characteristic prediction Aerodynamic characteristic Axisymmetric model

Newtonian limit of Einstein equation with a cosmological constant

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chinese Physics C 2024年第10期48卷 264-274页

作者： Li-fang Li Zhoujian Cao Xiaokai He institute of Mechanics Chinese Academy of SciencesBeijing 100190China institute of applied mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Fundamental Physics and Mathematical sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China School of mathematics and Statistics Hunan First Normal UniversityChangsha 410205China

Traditionally,the cosmological constant has been viewed as dark energy that mimics matter with negative *** that matter with negative energy provides a repulsive force,which fundamentally differs from typical gravitational forces,it has been believed that the cosmological constant effectively contributes a repulsive ***,it is important to note that the concept of gravitational force is valid only within the framework of Newtonian *** this study,we demonstrate that the traditional understanding of the gravitational force contributed by the cosmological constant is not entirely *** approach involves investigating the Newtonian limit of the Einstein equation with a cosmological *** subtleties involved in this analysis are discussed in ***,we find that the effect of the cosmological constant on Newtonian gravity is an attractive force rather than a repulsive one for ordinary *** expected,this corrective force is negligibly ***,our findings may offer a way to distinguish between dark energy and the cosmological constant,as one contributes a repulsive force while the other contributes an attractive force.

关键词： cosmological constant dark matter Einstein equation Newtonian limit dark energy

Run-and-Tumble Dynamics and Mechanotaxis Discovered in Microglial Migration

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Research 2024年第2期2023卷 95-103页

作者： Yiyu Zhang Da Wei Xiaochen Wang Boyi Wang Ming Li Haiping fang Yi Peng Qihui Fan fangfu Ye beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical sciences University of Chinese Academy of SciencesBeijing 100049China Wenzhou institute University of Chinese Academy of SciencesWenzhouZhejang 325000China Songshan Lake Materials Laboratory DongguanGuangdong 523808China School of science East China University of Science and TechnologyShanghai 200237China Oujang Laboratory(Zhejiang Lab for Regenerative Medicine Vision and Brain Health)WenzhouZhejiang 325000China

Microglia are resident macrophage cells in the central nervous system that search for pathogens or abnormal neural activities and migrate to resolve the *** effective search and targeted motion of macrophages mean dearly to maintaining a healthy brain,yet little is known about their migration *** this work,we study microglial motion with and without the presence of external *** discover that the cells are promptly attracted by the applied forces(i.e.,mechanotaxis),which is a tactic behavior as yet unconfirmed in ***,in both the explorative and the targeted migration,microglia display dynamics that is strikingly analogous to bacterial run-and-tumble motion.A closer examination reveals that microglial run-and-tumble is more sophisticated,e.g.,they display a short-term memory when tumbling and rely on active steering during runs to achieve mechanotaxis,probably via the responses of mechanosensitive ion *** differences reflect the sharp contrast between microglia and bacteria cells(eukaryotes ***)and their environments(compact tissue ***).Further analyses suggest that the reported migration dynamics has an optimal search efficiency and is shared among a subset of immune cells(human monocyte and macrophage).This work reveals a fruitful analogy between the locomotion of 2 remote systems and provides a framework for studying immune cells exploring complex environments.

关键词： analogy closer prompt

A citrullinated antigenic vaccine in treatment of autoimmune arthritis

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science Bulletin 2024年第18期69卷 2920-2929页

作者： Xu Jin Tianya Dong Qian Wang Yang Xie Xiangyu fang Chaonan Wei Shuyan Liu Xi Zheng Ping Wang Danxue Zhu Lulu Cao Suwei Dong Kechi fang Chao Zhong Jing Wang Fanlei Hu Zhanguo Li Department of Rheumatology and Immunology Peking University People’s Hospital&Beijing Key Laboratory for Rheumatism Mechanism and Immune DiagnosisBeijing 100044China Peking-Tsinghua Center for Life sciences Peking UniversityBeijing 100871China CAS Key Laboratory of Mental Health Institute of PsychologyChinese Academy of SciencesBeijing 100101China Department of Psychology University of Chinese Academy of SciencesBeijing 100049China Department of Chemical Biology School of Pharmaceutical SciencesPeking UniversityBeijing 100191China institute of systems Biomedicine Department of ImmunologyNHC Key Laboratory of Medical Immunology(Peking University)Beijing Key Laboratory of Tumor Systems BiologyPeking University Health Science CenterBeijing 100191China State Key Laboratory of Natural and Biomimetic Drugs School of Pharmaceutical SciencesPeking UniversityBeijing 100191China Department of Integration of chinese and Western Medicine School of Basic Medical SciencesPeking UniversityBeijing 100191China

Rheumatoid arthritis(RA)is an inflammatory autoimmune disease triggered by antigenic peptides with environmental and genetic risk *** has been shown that antigen-specific targeting could be a promising therapeutical strategy for RA by restoring immune tolerance to self-antigens without compromising normal *** of antigens enhances antigenic properties and induces autoimmune ***,we showed that citrullinated antigenic(citAg)vaccine ameliorated collageninduced arthritis with decreased T-helper 1(Th1)and Th17 cells,downregulated proinflammatory cytokines including interlukin-6 and tumor necrosis factor-a,and inhibited antigen recall responses.B cell receptor sequencing further revealed that citAg vaccine could dampen the dysregulated V(D)J recombination,restoring the immune *** together,the results demonstrated that citAg vaccine might have a therapeutic effect on RA.

关键词： CitAg Citrullination Collagen typeⅡ Therapeutic vaccine Immune tolerance Rheumatoid arthritis

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肝器官芯片在生物医学研究中的应用进展

合成生物学 2024年第4期5卷 813-830页

作者：陈汐玥王亚清包芳秦建华中国科学院大连化学物理研究所辽宁大连116023 中国科学院大学北京100049 中国科学技术大学安徽合肥230026 中国科学技术大学苏州高等研究院江苏苏州215123

肝脏具有复杂结构和多种功能,包括血糖调控、蛋白合成、解毒和药物代谢等,在维持人体正常生理活动中起着重要作用。传统的二维细胞培养和动物模型已被广泛用于肝脏生理或疾病研究,但它们在反映人体组织真实微环境和对药物反应等方面仍... 详细信息

肝脏具有复杂结构和多种功能,包括血糖调控、蛋白合成、解毒和药物代谢等,在维持人体正常生理活动中起着重要作用。传统的二维细胞培养和动物模型已被广泛用于肝脏生理或疾病研究,但它们在反映人体组织真实微环境和对药物反应等方面仍存在一定局限。因此,建立高仿真度肝脏体外模型对于肝病研究、药效与毒性评价至关重要。本文概述了传统肝脏体外模型在实现近生理复杂微环境模拟、肝组织特异性功能准确复现等方面的局限性,总结了以器官芯片为代表的新型肝脏体外模型的设计策略、技术特点及其在生物医学领域的研究进展。文中重点介绍了肝器官芯片仿生构筑和实现肝组织微环境模拟的关键要素,包括多细胞组分、肝窦/肝小叶结构、生化因子梯度和流体因素等,并对未来结合其他先进手段(如类器官、生物材料和基因编辑等)等,建立高度生理相关性的肝器官芯片和微生理系统的发展前景予以展望。

关键词：肝脏器官芯片类器官疾病研究药物评价

Applications of the representative points in statistical simulations

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science China mathematics 2014年第12期57卷 2609-2620页

作者： fang KaiTai ZHOU Min WANG WenJun Division of science and Technology Beijing Normal University-Hong Kong Baptist UniversityUnited International College institute of applied mathematics Academy of Mathematics and Systems ScienceChinese Academy of Sciences Department of mathematics Hainan Normal University

The paper gives a new approach to statistical simulation and resampling by the use of numbertheoretic methods and representative points. Resempling techniques take samples from an approximate population. The bootstrap suggests to use a random sample to form an approximate population. We propose to construct some approximate population distribution by the use of two kinds of representative points, and samples are taken from these approximate distributions. The statistical inference is based on those samples. The statistical inference in this paper involves estimation of mean, variance, skewness, kurtosis, quantile and density of the population distribution. Our results show that the new method can significantly improve the results by the use of Monte Carlo methods.

关键词： bootstrap kernel density estimation normal distribution representative points resampling statistical simulation