基于混合模拟退火算法的内窥镜布局优化设计

工程中存在着大量的布局设计问题,很多都是NPC问题,很难求解。提出了以启发式方法和模拟退火算法相结合的混合算法,可用于带性能约束的布局优化设计问题。在实例中将胶囊式内窥镜空间布局问题转化为轴向截面和横截面两个平面问题分别求解,对于轴向截面的离散变量问题,首先采用启发式方法进行元件层初始序列的排布,再采用模拟退火算法进行布局优化;在横截面上对连续变量则直接进行优化。优化结果经验算合理有效,该算法也可供旋转舱等工程布局优化问题借鉴。     

Observations of passenger flow and verification of a crowd dynamics model

This paper reports observations of passenger flow in the Wuchang railway station in Wuhan, China during the Chinese Traditional Spring Festival in 2006. The data collected are used to verify a crowd dynamics model previously developed. The crowd dynamics model is based on simulating the global movement of each individual under the influence of the surrounding crowd, and the good agreement between the predictions and observations validates the prediction model. The crowd dynamics model suggests that the crowd movement speed is dominated by two factors： the front-back inter-person effect, and the pedestrian＇s self-motive. The first effect gives logarithmic relationship between the crowd speed and crowd density. The second factor depends on the individual motive driven with which people try to divorce themselves from the control of the crowd movement. The prediction model are helpful to guide the design of public traffic systems for effective crowd dispersal.     

共沉淀-固相法合成LiNi0.5Mn0.5O2正极材料

以共沉淀法制备出超细镍锰复合氧化物,然后与锂盐混合,在900 ℃烧结12 h得到层状LiNi0.5Mn0.5O2正极材料. XRD结果表明,镍锰复合氧化物前驱体为层状NiMnO3结构;LiNi0.5Mn0.5O2样品结晶完整为层状α-NaFeO2结构. 电化学测试结果表明:在 2.5～4.5 V 范围内,0.2 C和1 C倍率下,材料首次放电容量分别为172.7和149 mAh/g,并具有良好的循环性能.     

杯芳烃对Fe~(3 )离子的液膜传输研究

本文用气泡式准乳化液膜法研究了对叔丁基杯芳烃及其衍生物对Fe3 离子的液膜传输作用 ,并对其传输规律、影响因素 (源相及吸收相的酸度 ,金属离子的浓度 ,传输载体类型等 )及传输机理作了初步探讨 .     

低捻转杯纺纱实验与理论分析--提高低捻转杯纱强力探索

研究在转杯纺加捻区中加装阻扭件,然后选用相同的棉条纺制不同捻系数的转杯纱(加装阻扭件和不加装阻扭件)和环锭纱,并测试其成纱的强伸性能、表面形态和扭转性能.测试结果表明,加装阻扭件的转杯纱可以适当改善转杯纺的加捻效果,进而适当提高了转杯纱的成纱强力.     

Identity of cells that imprint H-2-restricted T-cell specificity in the thymus

The thymus has two important roles in controlling the specificity of T lymphocytes. First, T cells differentiating in the thymus are rendered tolerant of 'self' antigens, particularly antigens encoded by the major histocompatibility complex, the H-2 complex in mice. Second, the thymus imbues T cells with the property of H-2-restricted recognition of antigen, that is, the capacity of T cells to react with foreign antigens presented in association with self H-2 gene products. Until recently it has generally been assumed that self-tolerance and H-2-restricted specificity both reflect early T-cell contact with self H-2 determinants expressed on thymic epithelial cells. Recent evidence suggests, however, that intrathymic cells of the macrophage/dendritic cell (Mphi/DC) lineage also have a role in shaping T-cell specificity. In particular, it has been found that the tolerance to graft-type H-2 determinants which normally ensues when T cells differentiate in an H-2-different thymus fails to occur when the thymus is pretreated with deoxyguanosine (dGuo), a procedure that selectively destroys Mphi/DC but spares epithelial cells. In contrast to these findings on tolerance induction, evidence is presented here that dGuo-treated thymus grafts do imprint T cells with H--2-restricted specificity for antigen. It appears, therefore, that induction of tolerance and H--2 restriction are controlled by different cells in the thymus.     

Strategies for cloning unknown cellular flanking DNA sequences from foreign integrants

Many virus and transposon DNAs can integrate into the host genome. In this review, techniques, including inverse polymerase chain reaction (IPCR), novel Alu-PCR and vectorette- or splinkerette-PCR are introduced as possible strategies for cloning flanking DNA regions of the integrants. Targeted gene-walking PCR, restriction-site PCR, capture PCR, and panhandle PCR and boomerang DNA amplification are also described. The principles, advantages and limitations of each approach are discussed. Received 9 July 1998; received after revision 2 October 1998; accepted 7 October 1998     

Banach空间的很极凸性与很极光滑性

对实Banach空间引进了很极凸性（很极光滑性）的概念，讨论了这种新凸性（新光滑性）与其它凸性（光滑性）的关系，得到了一些新结果。