检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

可干预因素与关节运动损伤的因果关系

中国组织工程研究 2025年第9期29卷 1953-1962页

作者：董婷婷陈天鑫李妍张晟张磊中国中医科学院望京医院骨关节四科北京市100102

背景:生活方式、代谢特征及营养摄入等干预因素与关节运动损伤的因果关系逐渐得到临床研究的重视,然而可干预因素与关节运动损伤的因果关系尚不明确。目的:运用孟德尔随机化的方法,探讨可干预因素与关节运动损伤的因果关系,为运动损伤... 详细信息

背景:生活方式、代谢特征及营养摄入等干预因素与关节运动损伤的因果关系逐渐得到临床研究的重视,然而可干预因素与关节运动损伤的因果关系尚不明确。目的:运用孟德尔随机化的方法,探讨可干预因素与关节运动损伤的因果关系,为运动损伤预防提供依据。方法:从公开数据库获取可干预因素和关节运动损伤的GWAS数据集,运用逆方差加权法、MR-Egger法、加权中位数法探讨生活方式、代谢特征、营养摄入与关节运动损伤的因果关系。敏感性分析方面,采用Cochran’s Q检验、MR-Egger回归、留一法和MR-PRESSO,以验证结果的稳定性和可靠性。结果与结论:①生活方式方面,咖啡(OR=0.29,95%CI:0.10-0.79,P=0.016)、茶消耗量(OR=0.41,95%CI=0.19-0.85,P=0.017)与足踝关节运动损伤风险下降,咖啡消耗量(OR=3.31,95%CI=1.02-10.73,P=0.046)与肩关节运动损伤风险上升具有潜在因果关系;从未吸烟(OR=0.78,95%CI=0.70-0.87,P=1.49×10^(-5))与足踝关节运动损伤风险下降具有显著因果关系。②代谢特征方面,钙水平(OR=0.88,95%CI=0.79-0.98,P=0.017)与手腕关节运动损伤风险下降具有潜在因果关系。③营养摄入方面,维生素A摄入(OR=1.08,95%CI:1.02-1.13,P=0.007)与膝关节运动损伤风险增加具有潜在因果关系。④敏感性分析方面,Cochran’s Q检验显示存在异质性(P0.05),留一法显示逐个剔除单核苷酸多态性后,结果具有稳定性。⑤此研究初步揭示生活方式、代谢特征及营养摄入等可干预因素对关节运动损伤风险的影响,为关节运动损伤的预防提供研究证据与研究方向。

关键词：孟德尔随机化关节运动损伤可干预因素生活方式代谢特征营养摄入因果关系敏感性分析

A Note about Minimal Hypercones

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2021年第11期37卷 1794-1802页

作者： Yong sheng zhang School of Mathematical Sciences&IAS Tongji UniversityShanghai 200092P.R.China

This short note is concerned with a measure version criterion for hypersurfaces to be *** natural flows and associated reflections for many minimal hypercones,including minimal isoparametric hypercones and area-minimi... 详细信息

关键词： Minimal hypercone measure invariant flow foliation

Occupancy-aided ventilation for airborne infection risk control:Continuously or intermittently reduced occupancies?

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2023年第5期16卷 733-747页

作者： sheng zhang Dun Niu zhang Lin School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’anChina Division of Building Science and Technology City University of Hong KongChina

Ventilation is an important engineering measure to control the airborne infection risk of acute respiratory diseases,e.g.,Corona Virus Disease 2019(COVID-19).Occupancy-aided ventilation methods can effectively improve the airborne infection risk control performance with a sacrifice of decreasing working productivity because of the reduced *** study evaluates the effectiveness of two occupancy-aided ventilation methods,i.e.,the continuously reduced occupancy method and the intermittently reduced occupancy *** continuously reduced occupancy method is determined by the steady equation of the mass conservation law of the indoor contaminant,and the intermittently reduced occupancy method is determined by a genetic algorithm-based optimization.A two-scenarios-based evaluation framework is developed,i.e.,one with targeted airborne infection risk control performance(indicated by the mean rebreathed fraction)and the other with targeted working productivity(indicated by the accumulated occupancy).The results show that the improvement in the airborne infection risk control performance linearly and quadratically increases with the reduction in the working productivity for the continuously reduced occupancy method and the intermittently reduced occupancy method *** a given targeted airborne infection risk control performance,the intermittently reduced occupancy method outperforms the continuously reduced occupancy method by improving the working productivity by up to 92%.At a given targeted working productivity,the intermittently reduced occupancy method outperforms the continuously reduced occupancy method by improving the airborne infection risk control performance by up to 38%.

关键词： occupancy-aided ventilation continuously reduced occupancy intermittently reduced occupancy airborne infection risk rebreathed fraction working productivity

MULTIGRID ALGORITHM FOR THE COUPLING SYSTEM OF NATURAL BOUNDARY ELEMENT METHOD AND FINITE ELEMENT METHOD FOR UNBOUNDED DOMAIN PROBLEMS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2007年第1期25卷 13-26页

作者： sheng zhang Dehao Yu School of Mathematical Sciences and LPMC Nankai University Tianjin 800071 China LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

In this paper, some V-cycle multigrid algorithms are presented for the coupling system arising from the discretization of the Dirichlet exterior problem by coupling the natural boundary element method and finite element method. The convergence of these multigrid algorithms is obtained even with only one smoothing on all levels. The rate of convergence is found uniformly bounded independent of the number of levels and the mesh sizes of all levels, which indicates that these multigrid algorithms are optimal. Some numerical results are also reported.

关键词： Multigird algorithm Finite element method Boundary element method Coupling Unbounded domain problem.

3D HYBRID DEPTH MIGRATION AND FOUR-WAY SPLITTING SCHEMES

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2006年第4期24卷 463-474页

作者： Wen-sheng zhang Guan-quan zhang LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

The alternately directional implicit （ADI） scheme is usually used in 3D depth migration. It splits the 3D square-root operator along crossline and inline directions alternately. In this paper, based on the ideal of data line, the four-way splitting schemes and their splitting errors for the finite-difference （FD） method and the hybrid method are investigated. The wavefield extrapolation of four-way splitting scheme is accomplished on a data line and is stable unconditionally. Numerical analysis of splitting errors show that the two-way FD migration have visible numerical anisotropic errors, and that four-way FD migration has much less splitting errors than two-way FD migration has. For the hybrid method, the differences of numerical anisotropic errors between two-way scheme and four-way scheme are small in the case of lower lateral velocity variations. The schemes presented in this paper can be used in 3D post-stack or prestack depth migration. Two numerical calculations of 3D depth migration are completed. One is the four-way FD and hybrid 3D post-stack depth migration for an impulse response, which shows that the anisotropic errors can be eliminated effectively in the cases of constant and variable velocity variations. The other is the 3D shot-profile prestack depth migration for SEG/EAEG benchmark model with two-way hybrid splitting scheme, which presents good imaging results. The Message Passing Interface （MPI） programme based on shot number is adopted.

关键词： 3D depth migration Multiway splitting Data line Wavefield computation Finite-difference Hybrid method.

The YNEV stellar evolution and oscillation code

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2015年第4期15卷 549-568页

作者： Qian-sheng zhang Yunnan Observatories Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences

We have developed a new stellar evolution and oscillation code YNEV, which calculates the structures and evolutions of stars, taking into account hydrogen and helium burning. A nonlocal turbulent convection theory and an updated over- shoot mixing model are optional in this code. The YNEV code can evolve low- and intermediate-mass stars from the pre-main sequence to a thermally pulsing asymptotic branch giant or white dwarf. The YNEV oscillation code calculates the eigenfrequen- cies and eigenfunctions of the adiabatic oscillations for a given stellar structure. The input physics and numerical scheme adopted in the code are introduced. Examples of solar models, stellar evolutionary tracks of low- and intermediate-mass stars with different convection theories （i.e. mixing-length theory and nonlocal turbulent con- vection theory）, and stellar oscillations are shown.

关键词： stars -- stellar structure -- stellar evolution -- stellar oscillations

Strong Convergence Theorems for Strictly Asymptotically Pseudocontractive Mappings in Hilbert Spaces

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2011年第7期27卷 1367-1378页

作者： Shi sheng zhang Department of Mathematics Yibin University Yibin 644007 P. R. China

The purpose of this paper is by using CSQ method to study the strong convergence problem of iterative sequences for a pair of strictly asymptotically pseudocontractive mappings to approximate a common fixed point in a Hilbert space. Under suitable conditions some strong convergence theorems are proved. The results presented in the paper are new which extend and improve some recent results of Acedo and Xu [Iterative methods for strict pseudo-contractions in Hilbert spaces. Nonlinear Anal., 67（7）, 2258-2271 （2007）], Kim and Xu [Strong convergence of modified Mann iterations for asymptoti- cally nonexpansive mappings and semigroups. Nonlinear Anal., 64, 1140-1152 （2006）], Martinez-Yanes and Xu [Strong convergence of the CQ method for fixed point iteration processes. Nonlinear Anal., 64, 2400-2411 （2006）], Nakajo and Takahashi pings and nonexpansive semigroups. J. Math [Strong convergence theorems for nonexpansive map- Anal. Appl., 279, 372-379 （2003）], Marino and Xu [Weak and strong convergence theorems for strict pseudocontractions in Hilbert spaces. J. Math. Anal. Appl., 329（1）, 336-346 （2007）], Osilike et al. [Demiclosedness principle and convergence theorems for k-strictly asymptotically pseudocontractive maps. J. Math. Anal. Appl., 326, 1334-1345 （2007）], Liu [Convergence theorems of the sequence of iterates for asymptotically demicontractive and hemicontractive mappings. Nonlinear Anal., 26（11）, 1835-1842 （1996）], Osilike et al. [Fixed points of demi-contractive mappings in arbitrary Banach spaces. Panamer Math. J., 12（2）, 77-88 （2002）], Gu [The new composite implicit iteration process strictly pseudocontractive mappings. J. Math with errors for common fixed points of a finite family of Anal. Appl., 329, 766-776 （2007）].

关键词： Strictly asymptotically pseudocontractive mapping strictly pseudocontractive mapping of Browder Petryshyn type CSQ methods common fixed point

On Lawson's Area-minimizing Hypercones

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2016年第12期32卷 1465-1476页

作者： Yong sheng zhang School of Mathematics and Statistics Northeast Normal University

We show the area-minimality property of all homogeneous area-minimizing hypercones in Euclidean spaces （classified by Lawlor） following Lawson＇s original idea in his 72＇ Trans. A.M.S. paper ＂The equivariant Plateau problem and interior regularity＂. Moreover, each of them enjoys （coflat） calibrations singular only at the origin.

关键词： Area-minimizing hypercone coflat calibration comass

ADDED MASS OF UNDERWATER PLATES AND BEAM STIFFENED PLATES IN VIBRATION

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1991年第2期3卷 13-20页

作者： zhang, sheng-ming China Ship Scientific Research Cent Wuri China

In this paper, the added mass of plates and beam stiffened plates vibrating in water are summarized for the purpose of convenience in engineering design. The analytical formulae, calculated data tables, calculated cur... 详细信息

关键词： Mathematical Techniques Boundary Element Method Plates Vibrations Ships Vibrations Tanks Vibrations