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Acta Mechanica Sinica 2011年第4期27卷 510-518页

作者： qing-Dong cai Department of Mechanics and Aerospace Engineering College of Engineering Peking University 100871 Beijing

The Lattice Boltzmann method （LBM） is used to simulate the flow field in a bifurcate channel which is a simplified model of the draft tube of hydraulic turbine machine. According to the simulation results, some qualitative conclusions can be deduced. The reason of uneven flux in different branches of draft tube is given. Not only the vortex rope itself, but also the attenuation of the rotation strength is important in bringing on the uneven flux. The later leads to adverse pressure gradient, and changes the velocity profile. If the outlet contains more than one exit, the one that contains the vortex rope will lose flux because of this adverse pressure gradient. Several possible methods can be used to minimize the adverse pressure gradient domain in order to improve the efficiency of turbine machine.

关键词： Lattice Boltzmann method - Hydraulic turbinemachine Draft tube Vortex rope

Cyclical Deformations of Quadrangles in S^(2)_(κ)and Defining Properties of Alexandrov Spaces

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Acta Mathematica Sinica,English Series 2021年第4期37卷 597-640页

作者： qing Song cai Colledge of Science Tianjin University of TechnologyTianjin 300384P.R.China

This paper is mainly devoted to proving the four equivalent defining properties of a CBA(κ)*** proof is based on an interesting tool we established which describes the cyclical five-step deformation procedure for quadrangles in the model 2-plane S^(2)_(κ),including the limit shape of each *** a byproduct we give a complete list of cyclical deformation procedures for all kinds of quadrangles on *** last we make a contrast of geometric properties of CBA with CBB spaces,including a comparison between their defining properties and a discussion about Alexandrov’s Lemma.

关键词： Spherical quadrangle Alexandrov spaces CBA spaces CBB spaces

Systematic diesel molecular performance evaluation based on quantitative structure-property relationship model

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Petroleum Science 2022年第2期19卷 809-818页

作者： Guang-qing cai Lin-Zhou Zhang State Key Laboratory of Heavy Oil Processing Petroleum Molecular Engineering Center(PMEC)China University of PetroleumBeijing 102249China

The production and separation of optimal molecules in diesel fuels require a systematic property evaluation for the containing *** paper evaluates the diesel molecules based on four key quality indicators:low-temperature fluidity,cleanliness,ignition,and power *** established the corresponding quantitative structure-property relationship models for corresponding properties,which are freezing point,yield sooting index,cetane number,and combustion *** models were applied for the screening of the high-performance molecules that is suitable for *** molecular performance distribution of the conventional diesel and biodiesel were also ***,we analyzed the effect of different transformation paths on molecular properties,giving guidance on the conversion process design.

关键词： Diesel Optimal molecules QSPR Molecular screening

A Generalization of Implicit Ore-condition for Hamiltonicity of k-connected Graphs

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Acta Mathematicae Applicatae Sinica 2020年第3期36卷 620-626页

作者： Jun-qing cai Lin WANG School of Management Qufu Normal UniversityRizhao 276826China

In 2005,Flandrin et *** that if G is a k-connected graph of order n and V(G)=X1∪X2∪···∪Xk such that d(x)+d(y)≥n for each pair of nonadjacent vertices x,y∈Xi and each i with i=1,2,···,k,then G is *** order to get more sufficient conditions for hamiltonicity of graphs,Zhu,Li and Deng proposed the definitions of two kinds of implicit degree of a vertex v,denoted by id1(v)and id2(v),*** this paper,we are going to prove that if G is a k-connected graph of order n and V(G)=X1∪X2∪···∪Xk such that id2(x)+id2(y)≥n for each pair of nonadjacent vertices x,y∈Xi and each i with i=1,2,···,k,then G is hamiltonian.

关键词： implicit degree Hamiltonian cycle cyclability

Effect of basic fibroblast growth factor and danshen on bcl-2 and p53 mRNA expression in the brain of rats exposed to repeated, high, positive acceleration (+Gz)

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Neural Regeneration Research 2008年第7期3卷 747-750页

作者： Hongjin Liu qing cai Military Researching Center of Aeropathy Air-force General Hospital of Chinese PLA Beijing 100036 China

BACKGROUND： Both animal experiments and clinical studies have shown that basic fibroblast growth factor （bFGF） and danshen （Salvia miltiorrhiza） can exhibit protective effects on ischemia-reperfusion cerebral injury. OBJECTIVE： To test whether bFGF and danshen can protect cerebral injury induced by exposure to repeated, high, positive acceleration （＋Gz） in an animal model and to analyze the possible mechanisms. DESIGN, TIME AND SETTING： Randomized controlled animal study. The experiment was performed at the Research Center for Molecular Biology, Air-force General Hospital of Chinese PLA from April to August 2000. MATERIALS： A total of 20 clean grade, healthy, Sprague Dawley rats of both genders, weighing （200 ± 15） g, were provided by our experimental animal center. Rats were randomly divided into 5 groups： the control group, ＋Gz exposure group, bFGF group, danshen group, and saline group, with 4 animals per group. bFGF （Beijing Bailuyuan Biotechnology Co. Ltd.） and danshen solution （Shanghai Zhongxi Pharmaceutical Co. Ltd.） were used. METHODS： All rats were fixed on a rotary arm of a centrifugal apparatus （2 m in radius） with their heads oriented towards the center of the apparatus. Except for rats in the control group, the value of ＋Gz exposure was ＋14 Gz with an acceleration rate of 1.5 G/s. The peak force lasted for 45 seconds. ＋Gz exposure was performed three times with intervals of 30 minutes. Rats in the control group received the same ＋Gz procedure, but the G value was ＋1 Gz. Rats in bFGF group and danshen group were intraperitoneally injected with 100 μg/kg bFGF or 15 g/kg danshen solution, respectively, at 30 minutes prior to centrifugation and immediately after centrifugation. Rats in saline group were injected with the same volume of saline. Six hours after exposure, rats were decapitated. One hemisphere was preserved in liquid nitrogen for RNA extraction and the other was processed for apoptosis detection. MAIN OUTCOME MEASURES： mRNA levels of

关键词： positive acceleration rats apoptosis bcl-2 p53 gene expression basic fibroblast growth factor danshen

Collision risk assessment of reduced aircraft separation minima in procedural airspace using advanced communication and navigation

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Chinese Journal of Aeronautics 2023年第4期36卷 315-337页

作者： qing cai Hao Jie ANG Sameer ALAM Air Traffic Management Research Institute School of Mechanical&Aerospace EngineeringNanyang Technological University639798Singapore

With the advancement of Communication,Navigation and Surveillance(CNS)technolo-gies such as space-based Automatic Dependent Surveillance-Broadcast/Contract(ADS-B/C),large separation minima may be reduced in procedural *** is of great significance to know the upper limit of the Reduced Separation Minima(RSM)for a procedural airspace and the corre-sponding consequences on collision risk with specifics of the advanced ADS-B and control interven-tion *** this work,an interactive software is first developed for collision risk *** software integrates the International Civil Aviation Organization(ICAO)collision risk models for lateral and longitudinal collision risk calculation for the Singapore procedural *** demonstrate that the lateral and longitudinal collision risk of Singapore procedural airspace with respect to current control procedures meets the ICAO Target Level of Safety(TLS)***,the feasibility of reducing the horizontal separations implemented in the Singapore pro-cedural airspace with respect to advanced CNS techniques is *** is found that if advanced CNS technologies are applied,then the current 50-NM lateral and longitudinal separa-tion standards can be reduced to 22 NM(1 NM=1.825 km)and 20 NM,respectively,to meet the TLS standards based on current demand.A method is then devised to expand the traffic demand by p for p∈[10%,200%].It is found that the minimum lateral and longitudinal separa-tions can be reduced from 50 NM to be within the range of[23,31]NM,and 20 NM,respectively,for p∈[10%,200%],while the collision risk still meets the TLS standards.

关键词： Air transportation Collision risk Procedural airspace Separation minima Space-based Automatic Dependent Surveillance-Bro adcast/Contract(ADS-B/C)

An Implicit Degree Condition for Relative Length of Long Paths and Cycles in Graphs

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Acta Mathematicae Applicatae Sinica 2016年第2期32卷 365-372页

作者： Jun-qing cai Hao LI School of Management Qufu Normal University L.R.I UMR 8623 CNRS and Universit'e Paris-Sud 11 Institute for Interdisciplinary Research Jianghan University

For a graph G, we denote by p（G） and c（G） the number of vertices of a longest path and a longest cycle in G, respectively. For a vertex v in G, id（v） denotes the implicit degree of v. In this paper, we obtain that if G is a 2-connected graph on n vertices such that the implicit degree sum of any three independent vertices is at least n ＋ 1, then either G contains a hamiltonian path, or c（G）〉 p（G） - 1.

关键词： Hamiltonian path dominating cycles implicit degree longest paths longest cycles

Mechanisms Underlying Brain Aging Under Normal and Pathological Conditions

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Neuroscience Bulletin 2023年第2期39卷 303-314页

作者： Menglong Jin Shi-qing cai Institute of Neuroscience and State Key Laboratory of Neuroscience CAS Center for Excellence in Brain Science and Intelligence TechnologyChinese Academy of SciencesShanghai 200031China University of Chinese Academy of Sciences Beijing 100049China

Aging is a major risk factor for many human diseases,including cognitive impairment,which affects a large population of the *** the past few decades,our understanding of the molecular and cellular mechanisms underlying the changes associated with aging and age-related diseases has expanded greatly,shedding light on the potential role of these changes in cognitive *** this article,we review recent advances in understanding of the mechanisms underlying brain aging under normal and pathological conditions,compare their similarities and differences,discuss the causative and adaptive mechanisms of brain aging,and finally attempt to find some rules to guide us on how to promote healthy aging and prevent age-related diseases.

关键词： Healthy aging Pathological aging Cognitive impairment

An Implicit Degree Ore-condition for Pancyclicity of Graphs

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Acta Mathematica Sinica,English Series 2013年第9期29卷 1773-1780页

作者： Hao LI Jun qing cai L.R.I UMR 8623 CNRS and Universit Paris-Sud 11 F-91405 Orsay France Institute for Interdisciplinary Research Jianghan University School of Management Qufu Normal University

In 1989, Zhu, Li and Deng introduced the definition of implicit degree of a vertex v in a graph G, denoted by id（v）. In this paper, we prove that if G is a 2-connected graph of order n such that id（u）＋ id（v） ≥ n for each pair of nonadjacent vertices u and v in G, then G is pancyclic unless G is bipartite, or else n = 4r, r ≥ 2 and G is isomorphic to F4r .

关键词： Implicit degree Hamilton cycle pancyclic graph

On the rate of convergence of two generalized Bernstein type operators

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Applied Mathematics(A Journal of Chinese Universities) 2020年第3期35卷 321-331页

作者： LIAN Bo-yong cai qing-bo Department of Mathematics Yang-En UniversityQuanzhou 362014China School of Mathematics and Computer Science Quanzhou Normal UniversityQuanzhou 362000China

In this paper,we introduce the Bézier variant of two new families of generalized Bernstein type *** establish a direct approximation by means of the Ditzian-Totik modulus of smoothness and a global approximation theorem in terms of second order modulus of *** means of construction of suitable functions and the method of Bojanic and Cheng,we give the rate of convergence for absolutely continuous functions having a derivative equivalent to a bounded variation function.

关键词： Bernstein operators modulus of smoothness rate of convergence bounded variation