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提出一种新的求解时间变换系数的方法,充分发挥时间变换的作用,只需较少的谐波项便可求解一般近似法不能求解的问题,改善了某些求解过程的收敛性  相似文献   
23.
5 种两栖爬行动物首次在广东省发现   总被引:2,自引:0,他引:2  
记述了广东省两栖动物新记录2种:大花角蟾Megophrys giganticus、黑眼睑小树蛙Phylautus gracilipes以及爬行动物新记录3种:半叶趾虎独山亚种Hemiphylodactylus yunnanensis dushangnensis、广西后棱蛇Oligodon guangxinsis、侧条后棱蛇Oligodon Lateralis、半叶践虎属Hemiphylodactylus亦为广东省新记录.  相似文献   
24.
The density distribution and internal structure of trabecular bone are modulated by local mechanical environment. In this study, an orthotropic adaptation algorithm was applied to the 3D femur model to simulate the variations of stiffness and orientation of trabecular bone under multi-loading conditions. This algorithm includes the determination of orthotropic axes and the stiffness modification of trabecular bone. Three methods were used to determine the orthotropic axes, i.e. the maximal cycle method, the stress maximum method, and the composite method. We found that the composite method was better than the other two. Firstly, the characteristics of density distribution obtained by using the composite method agreed better with those in real proximal femur. Secondly, the material orientation aligned with the known trabeculaer pattern. Finally, the ratios of the longitudinal modulus to the transverse modulus were also shown to be realistic in three local regions of the proximal femur.  相似文献   
25.
An international workshop on urban meteorology: observation and modeling, was jointly held by the Institute of Urban Meteorology (China) and the National Center for Atmospheric Research (US) in Beijing, October, 2004. The workshop was inten ded to share recent progress in urban meteorological research, discuss issues re lated to research and development priorities faced by diverse Chinese institutio ns, and explore collaboration opportunities between Chinese and US research inst itutions. This article summarizes the major issues discussed at the workshop, in cluding observation on urban boundary layer, urban landuse modeling, socioecon omic impacts of weather and climates, and air quality in urban environment. It i ncludes recommendations for future urban meteorology observational and modeling research, and potential collaborative opportunities between China and US.  相似文献   
26.
The objective of this paper is to introduce three semi-automated approaches for ontology mapping using relatedness analysis techniques. In the architecture, engineering, and construction (AEC) industry, there exist a number of ontological standards to describe the semantics of building models. Although the standards share similar scopes of interest, the task of comparing and mapping concepts among standards is challenging due to their differences in terminologies and perspectives. Ontology mapping is therefore necessary to achieve information interoperability, which allows two or more information sources to exchange data and to re-use the data for further purposes. The attribute-based approach, corpus-based approach, and name-based approach presented in this paper adopt the statistical relatedness analysis techniques to discover related concepts from heterogeneous ontologies. A pilot study is conducted on IFC and CIS/2 ontologies to evaluate the approaches. Preliminary results show that the attribute-based approach outperforms the other two approaches in terms of precision and F-measure.  相似文献   
27.
应用有限元法研究了剪切面边界条件对正交金属切削中工件表面层加工硬化深度的影响。有限元分析结果表明,剪切面法向应力分布对表面层硬化深度无显著影响,剪切面长度是影响硬化深度的主要因素。  相似文献   
28.
Summary Mice bearing L1210 leukemia did not show impaired humoral or cellular immune response to antigenic stimulation during the early stage of the tumor, and a depressed response was noted only in the terminal stage. L1210 cells were shown to suppress inflammatory reaction in vivo.Supported in part by USPHS research grant No.5-01-RR05-352-12, and by theIndependent Order of Foresters, San Bernardino District 3208. We acknowledge the valuable assistance ofJudith Johnson andJames Tan in this project. Histopathological examination byDick H. Koobs is appreciated.  相似文献   
29.
Psychiatric illness, such as affective disorders, anxiety disorders and schizophrenia, exerts exceptional personal burden on affected individuals. Although not physically noticeable, these disorders cost enormously on ones’ family and society. Currently pharma-ceutical and psychological treatments are generally accepted as effective for psychiatric disorders, while the exact mechanisms underlying the treatment efficacy, etiology and neurobiology of the disorders remain elusive. In the past decade, "neurogenic hy-pothesis" emerged as an attempt to explain the nature of psychiatric illness. The origination of the hypothesis is based on several pre-clinical and clinical observations. First, stress, which is a common risk factor of the disorders, was found to suppress neurogenesis; second, treatment for the illnesses like antidepressants and antipsychotics were shown to improve neurogenesis and behavioral deficits simultaneously; and third, the therapeutic effect of antidepressants was abolished in animal models when neuro-genesis was blocked. Increasing efforts were invested to determine whether neurogenesis is a key to the understanding and treatment of psychiatric disorders, although contrasting results are also found and thus the importance of neurogenesis remains a matter of debate. The present chapter will discuss the recent findings about the involvement of neurogenesis in major depression, anxiety disorders and schizophrenia, and whether neurogenesis would be a potential target for development of the treatment in the future.  相似文献   
30.
The ubiquitin–proteasome pathway of protein degradation is one of the major mechanisms that are involved in the maintenance of the proper levels of cellular proteins. The regulation of proteasomal degradation thus ensures proper cell functions. The family of proteins containing ubiquitin-like (UbL) and ubiquitin-associated (UBA) domains has been implicated in proteasomal degradation. UbL–UBA domain containing proteins associate with substrates destined for degradation as well as with subunits of the proteasome, thus regulating the proper turnover of proteins.  相似文献   
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