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The Regulation of Gonadal Somatic Cell Differentiation in Humans

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Genomics, Proteomics & Bioinformatics 2022年第2期20卷 219-222页

作者： min chen Fei Gao Guangdong and Shenzhen Key Laboratory of Male Reproductive Medicine and Genetics Institute of UrologyPeking University Shenzhen HospitalShenzhen Peking University-The Hong Kong University of Science and Technology Medical CenterShenzhen 518036China State Key Laboratory of Stem Cell and Reproductive Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China Institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijing 100101China Beijing Institute for Stem Cell and Regenerative Medicine Beijing 100101China University of Chinese Academy of Sciences Beijing 100049China

In mammals,both male and female gonads are derived from the bipotential gonadal primordium,i.e.,the genital *** germ cells(PGCs)are the germ cell progenitors that arise from the extraembryonic ectoderm,migrate through the hindgut endoderm,and reach the genital ridge before sex determination[1].Both Sertoli cells and granulosa cells are derived from somatic cells in undifferentiated genital *** differentiation of germ cells and gonadal somatic cells during gonad development is regulated by various factors,including transcription factors,epigenetic regulators,and environmental *** interactions between germ cells and somatic cells also play critical roles in gonad development and PGC differentiation.

关键词： progenitor migrate differentiated

A multi-fidelity simulation method research on front variable area bypass injector of an adaptive cycle engine

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Chinese Journal of Aeronautics 2022年第4期35卷 202-219页

作者： Zhewen XU ming LI Hailong TANG min chen School of Energy and Power Engineering Beihang UniversityBeijing 100083China Aero Engine Academy of China Beijing 101300China Research Institute of Aero-Engine Beihang UniversityBeijing 102206China

Front Variable Area Bypass Injector(Front-VABI) is a component of the Adaptive Cycle Engine(ACE) with important variable-cycle features. The performance of Front-VABI has a direct impact on the performance and stability of ACE, but the current ACE performance model uses approximate models for Front-VABI performance calculation. In this work, a multi-fidelity simulation based on a de-coupled method is developed which delivers a more accurate calculation of the Front-VABI performance based on Computational Fluid Dynamics(CFD) simulation. This simulation method proposes a form of Front-VABI characteristic and its matching calculation method between it and the ACE performance model, constructs a coupling method between the(2-D) Front-VABI model and the(0-D) ACE performance model. The result shows, when ACE works in triple bypass mode, the approximate model cannot account for the effect of FrontVABI pressure loss on Core Driven Fan Stage(CDFS) design pressure ratio, and the calculated error of high-pressure turbine inlet total temperature is more than 40 K in mode transition condition(the transition operating condition between triple bypass mode and double bypass mode). In double bypass mode, the approximate model can better simulate the performance of FrontVABI by considering the local loss of area expansion. This method can be applied to the performance-optimized design of Front-VABI and the ACE control law design during mode transition.

关键词： Adaptive cycle engine Computational fluid dynamics Front variable area bypass injector Multi-fidelity simulation Performance model

Distribution of radium-224 in the western Arctic Ocean

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Acta Oceanologica Sinica 2005年第6期24卷 109-116页

作者： QIU Yusheng chen min LI Yanping Department of Oceanography Xiamen University Xiamen 361005 China State Key Laboratory of Marine Environmental Science Xiamen University Xiamen 361005 China Department of Oceanography Xiamen University Xiamen 361005 China

Radium-224 activities in the western Arctic Ocean were measured viaship-board ^(220)Rn emanation technique during the Second Chinese National Arctic Expedition. Theresults showed that the ^(224)Ra activities in the study areas ranged from being less than 0.08 to3.58 Bq/m^3, with an average of 0.23 Bq/m^3. The low ^(224)Ra concentration in the surface water wasattributed to the influence of sea ice melted water. The horizontal distribution of surface^(224)Ra in the western Arctic Ocean showed a high ^(224)Ra characteristics occurred along the slopearound 160°W, providing evidence for the importance of ice-rafted sediments to controlling thedistribution of radium isotopes in the Arctic Ocean. Mostly, ^(224)Ra concentrations increased withthe depth in the shelf region and reached a maximum at 75 m at the central Canada Basin, whichfurther confirms the importance of the transport of shelf bottom water to maintaining the upperhalocline layer in the Canada Basin.

关键词： ^(224)Ra distribution western arctic ocean

Topological relations between spherical spatial regions with holes

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International Journal of Digital Earth 2020年第4期13卷 429-456页

作者： Jingwei Shen Lan Zhang min chen Chongqing Engineering Research Center for Remote Sensing Big Data Application School of Geographical SciencesSouthwest UniversityChongqingPeople’s Republic of China Key Laboratory of Virtual Geographic Environment(ministry of Education) Nanjing Normal UniversityNanjingPeople’s Republic of China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application NanjingJiangsuPeople’s Republic of China

There is growing interest in globally modelling the entire *** topological relations between spherical simple regions and topological relations between regions with holes in the plane have been investigated,few studies have focused on the topological relations between spherical spatial regions with *** 16-intersection model(16IM)is proposed to describe the topological relations between spatial regions with holes.A total of 25 negative conditions are proposed to eliminate the impossible topological relations between spherical spatial regions with *** results show that(1)3 disjoint relations,3 meet relations,66 overlap relations,7 cover relations,3 contain relations,1 equal relation,7 coveredBy relations,3 inside relations,1 attach relation,52 entwined relations,and 28 embrace relations can be distinguished by the 16IM and that(2)the formalisms of attach,entwined,and embrace relations between the spherical spatial regions without holes based on the 9IM and that between the spherical spatial regions with holes based on the simplified 16IM are different,whereas the formalisms of other types of relations between spherical spatial regions without holes based on the 9IM and that between the spherical spatial regions with holes based on a simplified 16IM are the same.

关键词： Topological relations spatial region with holes 16-intersection model(16IM) spatial analysis

Ruin Probability and Joint Distributions of Some Actuarial Random Vectors in the Compound Pascal Model

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Acta Mathematicae Applicatae Sinica 2011年第1期27卷 63-74页

作者： Xian-min Geng Shu-chen Wan College of Science Nanjing University of Aeronautics & Astronautics Nanjing 210016 China

The compound negative binomial model, introduced in this paper, is a discrete time version. We discuss the Markov properties of the surplus process, and study the ruin probability and the joint distributions of actuarial random vectors in this model. By the strong Markov property and the mass function of a defective renewal sequence, we obtain the explicit expressions of the ruin probability, the finite-horizon ruin probability, the joint distributions of T, U（T - 1）, ｜U（T）｜ and inf U（n）（i.e., the time of ruin, the surplus immediately before ruin, the deficit at ruin and maximal deficit from ruin to recovery） and the distributions of some actuarial random vectors.

关键词： Compound negative binomial model Ruin probability Sequence of up-crossing zero points,Ultimately leaving deficit time Joint distributions

Casimir Force at a Finite Cut-Off

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Communications in Theoretical Physics 2008年第12期50卷 1317-1322页

作者： XIONG Ai-min chen Xiao-Song Institute of Theoretical Physics Chinese Academy of Sciences P.O. Box 2735 Beijing 100080 China

We calculate the Casimir force at a finite cut-off A by summing the forces induced by the all fluctuation modes. We show that the Casimir force is independent of the cut-off function in the limit L∧ → ∞. There is a correction in the order of （L∧）^-2, when L∧ is finite and large. This correction becomes remarkable when L is comparable with the microscopic length scale ∧^-1. It has been demonstrated that the Casimir force at a finite cut-off should be defined by summing forces of all fluctuation modes, instead of the derivative of Casimir energy with respect to L where an additional derivative of the cut-off function has been introduced.

关键词： vacuum fluctuation Casimir force finite cut-off

Weighted Least Absolute Deviations Estimation for Periodic ARMA Models

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Acta Mathematica Sinica,English Series 2015年第8期31卷 1273-1288页

作者： Baoguo PAN min chen Yan WANG School of Mathematics and Statistics Hubei Engineering University Academy of Mathematics and Systems Science University of Chinese Academy of Sciences School of Statistics Capital University of Economics and Finance

This paper investigates the weighted least absolute deviations estimator（WLADE） for causal and invertible periodic autoregressive moving average（PARMA） models. Asymptotic normality of the estimator is derived unde... 详细信息

关键词： Periodic ARMA WLADE asymptotic normality strict periodic stationarity periodic ergodicity

Optimal Dividend-Equity Issuance Strategy in a Dual Model with Fixed and Proportional Transaction Costs

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Acta Mathematicae Applicatae Sinica 2015年第2期31卷 405-426页

作者： Shu-min chen Zhong-fei LI School of Management Guangdong University of Technology Sun Yat-sen Business School Research Center for Financial Engineering and Risk Management Sun Yat-sen University

In this paper, we consider the problem of optimal dividend payout and equity issuance for a company whose liquid asset is modeled by the dual of classical risk model with diffusion. We assume that there exist both proportional and fixed transaction costs when issuing new equity. Our objective is to maximize the expected cumulative present value of the dividend payout minus the equity issuance until the time of bankruptcy,which is defined as the first time when the company＇s capital reserve falls below zero. The solution to the mixed impulse-singular control problem relies on two auxiliary subproblems： one is the classical dividend problem without equity issuance, and the other one assumes that the company never goes bankrupt by equity *** first provide closed-form expressions of the value functions and the optimal strategies for both auxiliary subproblems. We then identify the solution to the original problem with either of the auxiliary problems. Our results show that the optimal strategy should either allow for bankruptcy or keep the company＇s reserve above zero by issuing new equity, depending on the model＇s parameters. We also present some economic interpretations and sensitivity analysis for our results by theoretical analysis and numerical examples.

关键词： dual risk model fixed transaction cost optimal dividend strategy optimal equity issuance strategy mixed impulse-singular control

List Vertex-arboricity of Planar Graphs without Intersecting 5-cycles

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Acta Mathematicae Applicatae Sinica 2020年第2期36卷 439-447页

作者： Wei-fan WANG Li HUANG min chen Department of Mathematics Zhejiang Normal UniversityJinhua 321004China

The vertex-arboricity a(G)of a graph G is the minimum number of colors required for a vertex coloring of G such that no cycle is *** list vertex-arboricity al(G)is the list-coloring version of this *** this paper,we prove that every planar graph G without intersecting 5-cycles has al(G)≤*** extends a result by Raspaud and Wang[On the vertex-arboricity of planar graphs,European ***.29(2008),1064-1075]that every planar graph G without 5-cycles has a(G)≤2.

关键词： planar graphs list vertex-arboricity intersecting cycles monochromatic cycle