Catastrophe mechanism and classification of discontinuity behavior in thermal science (Ⅱ) -- Cusp catastrophe

The catastrophe mechanisms of thermal performance characteristics of the firebox gas combustion system were analyzed from the viewpoint of catastrophe theory. The mathematical models of cusp catastrophe were established. The relationship between the thermal performance characteristics and the changing of system control variables was studied. The cusp catastrophe mechanisms of typical performance characteristics, such as kicking and lagging, and those of transition from quenching to igniting were explained. It was illustrated that discontinuity behavior of thermal systems with an "S" motion feature curve and lagging feature may be equivalently classified according to the topology of cusp catastrophe, influenced by two groups of independent control variables.     

DNA microarray synthesis by using PDMS molecular stamps (Ⅲ)-- Optimization for the reaction conditions

Optimization for the technological processes of fabricating oligonucleotide microarray by the molecular stamping method is studied in this note. Three factors that affect the pressing coupling reactions of the nucleosides are focused on: the stability of the chemical activities of the reaction solutions, the contamination of the remain of the reactive nucleotides among the different spots on the chip, and the influence of the capping reaction on the hybridization result. The experiments show that the acetonitrile solution of tetrazole and nucleoside monomer could maintain sufficient reactive activity for more than 10 h. An effective method has been used and proved to eliminate the residual reactive nucleosides on chip with small molecules containing hydroxyl group. Finally, the capping step-- a regular step in the conventional DNA chemical synthesis can be neglected in our on-chip DNA synthetic process, which would not affect its hybridization results.     

桑蚕品种培育动态--我国蚕业科学研究发展的动态与趋势(一)

从1979年以来的20年间,全国培育出国家审定桑品种11个,省级审定品种10多个,加上各地选拔的优良地方品种,共选拔培育了50多个优良桑树品种,良种推广面积已占全国栽桑面积的50%以上.
     

小清河底泥沉积物的形态分析(Ⅰ)——主成分及次要成分分析方法研究

采用透射电镜 ,红外光谱 ,X ray粉末衍射光谱 ,原子吸收光谱等现代技术对小清河底泥沉积物复杂化合物的形貌及其中无机化合物的物种进行了综合分析 ,结合相应样区的水质分析进一步确认了底泥沉积物中主、次成份的物种以及痕量重金属污染物的分子存在状态 .     

用量子化学方法预测PCDFs的Ah受体结合能力(1)--神经网络模型

利用AM1半经验量子化学方法计算135种多氯联苯并呋喃(PCDFs)的12种结构一性质参数,以30种已有文献值的PCDFs为训练样本,采用误差反向传播人工神经网络(BP—ANN)方法建立PCDFs芳烃(Ah)受体结合能力的定量结构活性关系(QSAR)方程,对训练样本集以外的3个测试样本的检验结果表明,模型具有相当高的精度(训练样本最大相对误差小于5％,检验样本最大相对误差小于7％),且误差频数符合正态分布,表明该模型可用于未知样本的定量预测,据此给出目前尚没有文献值的其余102种PCDFs的Ah受体结合能力的预测值。     

聚合物固体酸催化合成丙烯酸双酯 --(Ⅱ)丙烯酸双酯的合成与表征

采用磺化交联酚醛树脂作催化剂合成丙烯酸双酯，探讨催化剂用量，反应温度、醇酸投料比对转化率的影响，并采用GPC、IR对产物进行表征。     

单组元聚集体的聚集--迁移的模型

提出了可逆迁移过程和不可逆聚集过程共存的聚集体生长模型.假定聚集反应速率核为I(i;j)=2I,迁移反应速率核为K(i;j)=Jij或K(i;j)=Jj.建立Smoluchowski速率方程,由此求出了系统的集团浓度分布的精确解.结果表明,集团浓度分布符合标度特性.     

随机的算术几何平均

本文证明了在Ｂｅｔａ随机分布权重下,Ｌａｇraｎｇｅ和Ｌｅｇｅｎｄｒｅ两种算术几何平均的几乎处处收敛性,讨论了两种算术几何平均的一些性质。     

中板轧制过程板坯弯曲生成与抑制之二--采用上压法抑制板坯弯曲

研究在中板轧制过程中抑制板坯弯曲的措施，在国内外首次应用上压法轧制来抑制中板轧制过程中板坯生成的弯曲现象，从理论上建立了板坯上下表面温差与轧辊辊径差的关系，为现场提供配辊原则。     

欧洲实验动物福利前景

The use and welfare of laboratory animals in research are major issues in modern society. Both widespread public concern on welfare of animals and continuously increasing demands on quality of both animals and of biomedical research make the issues urgent and complex. As a result the use of laboratory animals is experiencing turmoil of rapidly changing regulations both at European and at international level.     

Learning Pet -- Intelligent Agents for WBE

An intelligent agent is any program that can be considered by the user to be acting as an assistant or helper, rather than as a tool in the manner of a conventional direct-manipulation interface. An agent should as well display some, but perhaps not all, of the characteristics that are associated with human intelligence: learning, inference, adaptability,independence, creativity, etc.. In order to make webbased education (WBE) more vividly and instructionally with learner's independence at the same time, the intelligent agent can act as a learning pet, which is affiliated with learner's score or grades and will grow up with learner's achievement. And during the course of study, the learning pet can provides any information required by the learner, gives hints if necessary when the learner doing his/her assignment, offers instructional guide for further study etc..     

攀西地区早白垩世以来地壳抬升运动的裂变径迹年龄研究

通过对扬于板块西缘攀枝花一西昌地区麻粒岩中锆石和磷灰石的裂变径迹(FT)年龄测定，首次研究和报道了该区中一新生代地壳的低温热历史和抬升运动过程，分析显示，锆石FT年龄为143．8—68．4Ma；磷灰石FT年龄为24．1—12．8Ma．磷灰石FT平均长度的变化范围在10．54—13．20μm．研究表明，攀西地区从早白垩世到白垩纪末期地壳抬升是十分缓慢的，抬升速率仅为46—51m/Ma；但从第三纪开始地壳抬升运动明显加快，抬升速率达208-391m/Ma．这可能是印度板块与欧亚板块碰撞效应．     

Amino acid sequence changes in the haemagglutinin of A/Hong Kong (H3N2) influenza virus during the period 1968--77

Haemagglutinin molecules from nine strains of A/Hong Kong/68 (H3N2) influenza virus, isolated between 1968 and 1977, were examined for changes in amino acid sequences. At least 18 changes, 9 of which were located precisely, occurred in the soluble tryptic peptides of the large haemagglutinin polypeptide (HA1) during this period. These peptides contained 262 residues (82% of HA1). In HA2, only two changes in 129 residues (58% of HA2) were detected. Sequential changes at a particular locus were not found; and as far as we can tell, once an amino acid changed, it did not change again in any subsequent variant examined.     

遥感图像格式GeoTIFF解析

介绍了TIFF格式的图像格式,GeoTIFF中GeoKey的存储结构和GeoTIFF支持的3种坐标空间,并引出了六大GeoTag(地理标志域),描述了它们的具体含义和相互关系.介绍了坐标转换和地理编码.最后阐述了GeoTIFF的优点及其应用前景.     

追求与失落--袭人人物形象分析

该文通过分析袭人的追求、失落及其反差所造成的悲剧情绪，说明袭人的悲剧所在，同时对袭人的悲剧和晴雯的悲剧进行了比较，说明袭人性格的悲剧色彩更浓。     

中药太白米的研究进展

综述了中药太白米在生药鉴定，化学成分，药理研究以及组织培养等方面的研究进展情况。     

美国信息管理教育——挑战与特色

分析了美国信息管理行业的素质要求,总结了使美国信息管理教育面临挑战的主要原因,并介绍了美国一些提供优秀信息管理教育的学院的共有特色。