平面六杆机构的运动分析及仿真

采用杆组法建立机构运动分析的数学模型。基于Ture Basic编程计算机构的运动参数,为动力学分析提供依据。使用虚拟样机技术对机构进行运动学仿真,计算结果及仿真结果相互验证,证明了杆组法分析的有效性和仿真结果的可靠性。     

A Project Risk Ranking Approach Based on Set Pair Analysis

Set Pair Analysis （SPA） is a new methodology to describe and process system uncertainty. It is different from stochastic or fuzzy methods in reasoning and operation, and it has been applied in many areas recently. In this paper, the application of SPA in risk ranking is presented, which includes review of risk ranking, introduction of Connecting Degree （CD） that is a key role in SPA., Arithmetic and Tendency Grade （TG） of CDs, and a risk ranking approach proposed. Finally a case analysis is presented to illustrate the reasonability of this approach. It is found that this approach is very convenient to operate, while the ranking result is more comprehensible.     

Nonnegative matrix factorization and its applications in pattern recognition

Matrix factorization has been widely used in many fields[1]. In numerical algebra, the large-scale and com- plex problems can be transformed into small-scale sim- ple subproblems by matrix factorization; in applied statistics, low rank approximation of or…     

Remote sensing of spatial patterns of urban renewal using linear spectral mixture analysis: A case of central urban area of Shanghai (1997―2000)

It is very important to integrate remote sensing with urban geography that the spectral mixture analysis technique is applied to urban land cover evolvement and its eco-environmental effect. Urban land cover is mainly composed of complicated artificial materials, which is the key factor to limit the development of the spectral mixture analysis technique. There are two main aspects in which the technique of spectral mixture analysis is applied to urban geography： one is to calculate vegetation fraction; the other is to build quantitative model of the urban impervious surface obtained from the combination between high albedo fraction and low albedo fraction. The technique of spectral mixture analysis is firstly applied to study urban renewal pattern, scale and mode which happened in Shanghai City from 1997 to 2000,     

Two typical phenomena from the numerical simulation of fire and smoke transport in a gymnasium fire

Building a large centralized atrium in a building has become favourable both to designers and owners. The space of an atrium in a hall, theatre or gymnasium, can occupy an area as large as thousands of square meters and a height as high as 10―30 meters[1…     

Strategy for the mapping of interactive genes using bulked segregant analysis method and Mapmaker/Exp software

A qualitative trait is usually controlled by a single gene, but it may be sometimes controlled by two or even more genes. This phenomenon is called gene interaction. Rapidly searching for linked mo- lecular markers via bulked segregant analysis (BSA) and then constructing regional linkage map with Mapmaker/Exp has become a common approach to mapping single major genes. However, methods and computer programs developed for mapping single major genes cannot be simply applied to interactive genes because the genetic patterns of gene interac- tions are quite different from that of single-gene in- heritance. Up to now, experimental methods for quickly screening molecular markers linked to inter- active genes and statistical methods and corre- sponding computer softwares for simultaneously analyzing the linkage relationships of multiple mo- lecular markers to an interactive gene have not been available. To solve this problem, in this paper, we propose a strategy for mapping interactive genes using BSA and Mapmaker/Exp. We demonstrate that all interactive genes can be mapped by the 'BSA Mapmaker/Exp' strategy using F2 generation (in a few cases, F3 generation is also needed). As BSA and Mapmaker/Exp have been broadly used in gene mapping studies and are well known by many re- searchers, the strategies proposed in this paper will be useful for practical researches.     

Response of downstream sediment to water resource development in mainstream of the Lancang River

The impact of hydropower cascades of the Lancang River on downstream sedimentation has become one of the key problems in the research of the transboundary water resource development and its possible environmental effects. In this paper, the newest sediment data series spanning 17 years （1987-2003） at Yunjinghong hydrometric station and Chiang Saen hydrometric station, in northern Thailand, are analyzed to reveal these effects. Monthly mean sediment concentration data of the two stations are compared in-phase and yearly series are analyzed by the method of correlation and regression analysis and causality test. The analysis result shows that, though both of them are located at lower reaches of Manwan and Dachaoshan hydropower stations which are already constructed and in use, the sediment responses of the two stations are different under the regulation of the hydropower stations Annual series at Yunjinghong station are positively correlated but do not match well with those at Chiang Saen station. In addition, the results of Granger causality test on the time series also suggest that the series of maximum monthly mean sediment concentration of the Yunjinghong station each year may give cause for the ones of Chiang Saen station, while the series of minimum monthly mean sediment concentration each year and annual mean sediment concentration of Yunjinghong do not evidently give cause for the ones of the other station. Undoubtedly, this discovery will provide new evidences to assess the impacts of cascades construction in mainstream of the Lancang River on the variation of downstream sediment and its transboundary effects.     

Variability of surface circulation in the South China Sea from satellite altimeter data

11-year satellite altimeter sea surface height （SSH） anomaly data from January 1993 to December 2003 are used to present the dominant spatial patterns and temporal variations of the South China Sea （SCS） surface circulation through Empirical Orthogonal Function （EOF） analysis. The first three EOF modes show the obvious seasonal variations of SSH in the SCS. EOF mode one is generally characterized by a basin-wide circulation. Mode two describes the double-cell basin scale circulation structure. The two cells were located off west of the Luzon Island and southeast of Vietnam, respectively. EOF mode three presents the mesoscale eddy structure in the western SCS, which develops into a strong cyclonic eddy rapidly from July to September. EOF mode one and mode three are also embedded with interannual signals, indicating that the SCS surface circulation variation is influenced by El Nino events prominently. The strong El Nino of 1997/98 obviously changed the SCS circulation structure. This study also shows that there existed a series of mesoscale eddies in the western SCS, and their temporal variation indicates intra-seasonal and interannual signals.     

大熊猫IL-2基因的克隆与序列分析

本实验应用反转录-聚合酶链反应（RT-PCR）技术，从ConA诱导培养的大熊猫外周血淋巴细胞总RNA中扩增得到大熊猫IL-2基因，并将其克隆到PGEM-T载体中．经菌落PER鉴定、序列测定及序列分析，结果表明，经克隆得到的IL-2基因开放阅读框由465个核苷酸组成，编码一个由155个氮基酸组成的多肽，包括编码20个氨基酸的信号肽和135个氨基酸的成熟肽，该基因（已在Genbank中登录，序列号为：DQ852339）与已知的其他哺乳动物如犬、猫、人、猪、牛、羊、马、兔、鼠等的IL-2核苷酸同源性在66.5％（鼠）～91．5％（犬）之间；IL-2编码氨基酸同源性在54．8％（鼠）-85．2％（犬）之间；进化树构建结果表明大熊猫与犬亲缘关系最近．