糖醇乙酯衍生物制备方法的改进──气相色谱法分离木糖、核糖、阿拉伯糖、葡萄糖和甘露糖

通过对单糖进行ＮａＢＨ＿４还原，用１－甲基咪唑作催化剂和乙酸酐反应生成醇糖乙酯，反应在室温１０ｍｉｎ即可完成，利用糖醇乙酯易挥发的特性，用ＯＶ－１７０１石英毛细管柱进行分离，得到了五个不同的单峰。     

IDX法测定湿地松种子生活力的研究

以水作衬比剂，对湿地松（Ｐｉｎｕｓ ｅｌｌｉｏｔｔｉ Ｅｎｇｅｌｍ）种子进行ＩＤＸ法检验其生活力的研究，结果表明：湿地松种子在２５℃水中浸２ｈ后，置床培养４８ｈ，用吸水纸吸去表面水份，用硅胶干燥９ｈ（３０℃），其Ｘ射线片上死活种子图像差异显著，其判读结果与发芽率基本一致。     

论情报的传递功能

本文从情报的三个基本属性之一的传递性出发,论述了情报传递的功能、传递途径及其特点,指出当前我国情报传递这一环节上需要解决的一些问题.     

山西师大学生身体形态发育的现状、特点及预测

本文通过对山西师大84——88级学生身体形态测试指标的统计分析,结果表明:历届学生身体形态发育呈下降趋势。其中,胸围普遍低于山西省大学生平均值,体型呈细长型与接粗型两极分布。为研究高师学生体质,进一步深化体育教学改革,提供了理论依据。     

改性ZSM－5分子筛催化法合成糠醇酯的研究

利用改性ＺＳＭ－５分子筛为催化剂，催化合成了丙酸糠酯，戊酸糠酯异戊酸糠酯及乙酸四氢糠酯，丙酸四氢糠酯，丁酸四氢禄酯。文中讨论了影响反应的诸因素。酯的收率为６０％～８０％之间。     

一类典型非线性需求下二度价格歧视的研究

对一类典型非线性需求函数条件下垄断厂商实施二度价格歧视的方法、程度和特点给出了较为系统的研究。     

健美操形体训练与降脂的初探

运用实验方法对重庆市某健身俱乐部A、B两组学员进行不同内容的健身实验，实验组在每次有氧健身操之前增加对身体各部位的器械训练，结果表明：实验组减脂量明显高于对照组。同时还能培养人们自觉锻炼身体的习惯，增强体质，塑造美好形体。     

Differentiated cells are more efficient than adult stem cells for cloning by somatic cell nuclear transfer

Since the creation of Dolly via somatic cell nuclear transfer (SCNT), more than a dozen species of mammals have been cloned using this technology. One hypothesis for the limited success of cloning via SCNT (1%-5%) is that the clones are likely to be derived from adult stem cells. Support for this hypothesis comes from the findings that the reproductive cloning efficiency for embryonic stem cells is five to ten times higher than that for somatic cells as donors and that cloned pups cannot be produced directly from cloned embryos derived from differentiated B and T cells or neuronal cells. The question remains as to whether SCNT-derived animal clones can be derived from truly differentiated somatic cells. We tested this hypothesis with mouse hematopoietic cells at different differentiation stages: hematopoietic stem cells, progenitor cells and granulocytes. We found that cloning efficiency increases over the differentiation hierarchy, and terminally differentiated postmitotic granulocytes yield cloned pups with the greatest cloning efficiency.     

Novel l_2-l_∞ controller design for LPV discrete time-delay systems

1.INTRODUCTION Manyreal worldsystemscanbemodeledaslinearpa rameter varying(LPV)systems[1],whosestate spacerepresentationmatricesarefunctionsofasetof parametersthataremeasurableinrealtime.Recent ly,manyresearchersathomeandabroadhavebeen engagedinthestabilityanalysisandgainscheduling controlofLPVsystemsextensivelyandagreatnum berofimportantresultshavebeenreportedinthelit erature(see,forinstance,Refs.[1～7]andtheref erencestherein).Mostoftheseresultsfocusoncon tinuous timecases,while…     

Composite interval mapping of QTL for dynamic traits

The theoretical foundation for mapping quantitative trait loci (QTL) was laid by Sax[1] who discovered the association between the segregation pattern of pigment markers with seed size of bean. However, statistical methods were not well developed until th…