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1.
In 1873, W. K. Clifford introduced a notion of parallelism in the three-dimensional elliptic space that, quite surprisingly, exhibits almost all properties of Euclidean parallelism in ordinary space. The purpose of this paper is to describe the genesis of this notion in Clifford’s works and to provide a historical analysis of its reception in the investigations of F. Klein, L. Bianchi, G. Fubini, and E. Bortolotti. Special emphasis is placed upon the important role that Clifford’s parallelism played in the development of the theory of connections. 相似文献
2.
以应用ProCAST和MAGMAsoft 2款软件为例,针对铸造工艺仿真设计前处理和过程处理每个环节的主要内容与使用方法进行了较为详细地归纳、分析和总结。提出了处理过程的技术路线,并系统地介绍了每项应用内容的操作平台与使用步骤,从而为高效地应用铸造工艺仿真设计提供理论和技术支持。 相似文献
3.
Beryl?Royer-Bertrand Carlo?RivoltaEmail author 《Cellular and molecular life sciences : CMLS》2015,72(8):1463-1471
The past decade has seen the emergence of next-generation sequencing (NGS) technologies, which have revolutionized the field of human molecular genetics. With NGS, significant portions of the human genome can now be assessed by direct sequence analysis, highlighting normal and pathological variants of our DNA. Recent advances have also allowed the sequencing of complete genomes, by a method referred to as whole genome sequencing (WGS). In this work, we review the use of WGS in medical genetics, with specific emphasis on the benefits and the disadvantages of this technique for detecting genomic alterations leading to Mendelian human diseases and to cancer. 相似文献
4.
Introduction3D garment CAD tools are increasingly required byclothing industries to assist the cloth design andmanufacturing process for quick response when faced withrapidly changing in style and fabrics with variable materialproperties. In the context of virtual prototyping, modelingand simulation of garment fitting to mannequin areattracting more and more people from both research andindustrial communities.Different approaches and techniques can be used… 相似文献
5.
Shurong LI Chunwang HOU 《系统科学与复杂性》2007,20(1):108-118
In this paper, the collision problem of two moving objects is investigated. The objects are described by two algebraic sets (ellipses or circles in the paper). The collision problem discussed involves both static and dynamic case. The static case is that each object moves with known velocity. We use nonlinear programming to decide whether the objects collide. The dynamic case is that each object is controlled by a constraint external force which can be regulated online. For the dynamic case, the collision problem can be modelled as a Minmax problem which can be solved by using differential games. If collision occurs, the time and place of the first collision are given. The moving trajectories are provided in the paper. 相似文献
6.
Astacin, a digestive zinc-endopeptidase from the crayfish Astacus astacus L., is the prototype for the 'astacin family', which includes mammalian metallo-endopeptidases and developmentally regulated proteins of man, fruitfly, frog and sea urchin. Here we report the X-ray crystal structure of astacin, which reveals a deep active-site cleft, with the zinc at its bottom ligated by three histidines, a water molecule and a more remote tyrosine. The third histidine (His 102) forms part of a consensus sequence, shared not only by the members of the astacin family, but also by otherwise sequentially unrelated proteinases, such as vertebrate collagenases. It may therefore represent the elusive 'third' zinc ligand in these enzymes. The amino terminus of astacin is buried forming an internal salt-bridge with Glu 103, adjacent to His 102. Astacin pro-forms extended at the N terminus, as observed for some 'latent' mammalian astacin homologues, did not exhibit this 'active' conformation, indicating an activation mechanism reminiscent of trypsin-like serine proteinases. 相似文献
7.
基于强跟踪滤波器估计的最优融合方法 总被引:5,自引:0,他引:5
在分布式雷达数据处理模式中 ,数据融合是获得较精确的目标轨迹的主要环节。为克服卡尔曼滤波器对初始值敏感、鲁棒性差和对机动目标跟踪性能差的缺陷 ,通过利用各传感器的观测数据 ,采用强跟踪滤波器对目标进行跟踪 ,以改善目标状态估计的精度。对判定源于同一目标的状态估计值 ,给出了一种估计状态线进行性组合的最优融合准则。得出了实际数据的实验结果。 相似文献
8.
McCarroll SA Hadnott TN Perry GH Sabeti PC Zody MC Barrett JC Dallaire S Gabriel SB Lee C Daly MJ Altshuler DM;International HapMap Consortium 《Nature genetics》2006,38(1):86-92
The locations and properties of common deletion variants in the human genome are largely unknown. We describe a systematic method for using dense SNP genotype data to discover deletions and its application to data from the International HapMap Consortium to characterize and catalogue segregating deletion variants across the human genome. We identified 541 deletion variants (94% novel) ranging from 1 kb to 745 kb in size; 278 of these variants were observed in multiple, unrelated individuals, 120 in the homozygous state. The coding exons of ten expressed genes were found to be commonly deleted, including multiple genes with roles in sex steroid metabolism, olfaction and drug response. These common deletion polymorphisms typically represent ancestral mutations that are in linkage disequilibrium with nearby SNPs, meaning that their association to disease can often be evaluated in the course of SNP-based whole-genome association studies. 相似文献
9.
10.
一种改进的实信号IFFT算法 总被引:1,自引:0,他引:1
由于重量轻、体积小、功耗低、功能强的小卫星工作在无人干预的低温 ,高辐射的空间环境中 ,因此星上计算机系统必须满足集成度高、寿命长、可靠性高、抗辐射能力强的要求。针对立体测绘小卫星的特点 ,我们设计了满足上述要求的集集中控制与分布控制优点于一身的星上计算机系统 ,对其可靠性进行了分析 ,并对提高其可靠性应采取的关键技术进行了简要的论述。 相似文献