正方体中异面直线研究报告

类别 异面直线种类组成数目 (对 )角的大小距离辅助图例正方体棱 :12条面对角线 :12条体对角线 4条(设棱长为 1)棱与棱 12× 4÷ 2 =2 490° 1棱与面对角线 12× 6=7245° 190° 22棱与体对角线 6× 4=2 44 5° 22面对角线与面对角线 12× 5÷ 2 =3 090° 160° 33面对角线与体对角线 12× 2 =2 490° 6正方体中异面直线研究报告@周敏$江苏省东台中学高二(10)班!(224200) @鲁洁$江苏省东台中学高二(10)班!(224200) @邹施凯$江苏省东台中学高二(10)班!(224200)指导教师 @杨晓翔$江苏省东台中学高二(10)班!(224200)指导教师…     

乙醇对超临界CO2中乙酰乙酸乙酯异构化平衡的影响

超临界流体（SCF）是物质所处的温度和压力同时高于其临界值时的流体．在超临界体系中存在特殊的分子间相互作用，从而使其具有诸如高压缩性、高扩散系数、强溶剂化力等许多独特的性质.在超临界流体研究领域引起人们普遍关注的问题之一是共溶剂效应（cosolventeffect），即在超     

FTIR study of hydrogen bonding of stearic acid with ethanol, dimethyl sulfoxide,and acetonitrile in supercritical CO_2

FTIR spectroscopy was used to study the hydrogen bonding of stearic acid with ethanol, dimethyl sulfoxide (DMSO),and acetonitrile in supercritical CO_2 at 318.15 K, and 12.5 and 16.5 MPa. The concentrations of the cosolvents range from 0—0.6 mol·L~(-1). The area percentage of absorption bands for hydrogen-bonded and nonhydrogen-bonded species was obtained from the IR spectra. The acid and the cosolvents can form hydrogen bond even when their concentrations are very low. At fixed solute concentration, the extent of hydrogenbonding increases with cosolvent concentration. At higher ethanol concentrations, it seems that one stearic acid molecule can hydrogen bond with more than one ethanol molecules simultaneously. It is seen that the strength of the hydrogen bond formed by the acid and the cosolvents is in the order: DMSO>ethanol>acetonitrile.     

Solubility of stearic acid in supercritical CO_2-acetonitrile mixtures

The solubility of stearic acid in supercritical CO2 with acetonitrile (CH3CN) cosolvent was measured at 318.15 K in the pressure range from 9.5 to 16.5 MPa, and the cosolvent concentration ranges from 0. 0 to 5.5 mol% . The solubility increases with acetonitrile concentration and pressure, and it also increases with the apparent density of CO2 d1(moles of CO2 in per liter of fluid) at higher cosolvent concentrations. At lower d1, however, the solubility of the acid at lower acetonitrile concentrations is lower than that in pure CO2 provided that d1 is fixed, which is discussed qualitatively based on the clustering of the components in the system.     

分子筛修饰电极的研究(Ⅱ)──NaY-聚乙烯醇电极对铅离子的响应

用吸附涂层法制备分子筛一高分子膜电极一直是人们感兴趣的课题之一［1～4］．但这类电极在一定程度上存在着分析灵敏度低，测定重现性差的缺点．本文采用分子筛（NaY型）－聚乙烯醇为涂层液，掺杂少量石墨粉，制备了分子筛一聚乙烯醇电极（ZPE）．在提高电极响应灵敏度和制备精密度方面进行了尝试，获得了较令人满意的结果．1实验部分1．1仪器与试剂DCG-2型多功能程序给定器；JSH-1型恒电位仪；GOULD60000型记录仪（英国）；JB-1型搅拌器；CQ500J超声波清洗器．NaY型分子筛（南京化工厂），聚乙烯醇［Mw=44．05n］，其它试剂均为…     

Phase equilibria of supercritical CO_2-ethanol-stearic acid ternary system and hydrogen bonding between ethanol and stearic acid

Ｓｕｐｅｒｃｒｉｔｉｃａｌｆｌｕｉｄｓ(ＳＣＦｓ)ｈａｖｅｍａｎｙｆｅａｔｕｒｅｓｓｕｃｈａｓｈｉｇｈｄｉｆｆｕｓｉｖｉｔｙ,ｌｏｗｖｉｓｃｏｓｉｔｙ,ａｎｄｈｉｇｈｃｏｍｐｒｅｓｓｉｂｉｌｉｔｙ.Ｔｈｅｓｅｍａｋｅｔｈｅｍａｔｔｒａｃｔｉｖｅｓｏｌｖｅｎｔｓｆｏｒｍａｎｙｉｎｄｕｓｔｒｉａｌｐｒｏｃｅｓｓｅｓ.Ｓｕｐｅｒｃｒｉｔｉｃａｌ(ＳＣ)ＣＯ2ｉｓｔｈｅｍｏｓｔｐｏｐｕｌａｒａｍｏｎｇｔｈｅｍ,ｂｅｃａｕｓｅｉｔｉｓｎｏｎｔｏｘｉｃ,ｎｏｎｆｌａｍｍａｂｌｅ,ｅａｓｙｔｏｏｂｔａｉｎ,ａｎｄｈａｓａ…     

正十二酸在超临界CO2中的红外光谱研究

正十二酸在超临界ＣＯ２中的红外光谱研究鲁洁金顺子冯峻波韩布兴阎海科（中国科学院化学研究所北京１０００８０）超临界流体（ＳＣＦｓ）是对比温度和对比压力同时大于１的流体，它的密度接近于液体，因而具有较强的溶剂化作用。ＳＣＦｓ的另一个重要特性是高度可压缩性...