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.     

The Assembly and Molecular Structure of a Novel One-dimensionalCyanide-bridged [Ni(pn)_2Ni(CN)_4]_n·nH_2 O Complex

IntroductionSincetheearlyworkofPedersen',CramZandLehn',molecularassemblyhasattractedmuchattentionfromscientistsofdifferentareas,rangingfromchemistrytosolid-statephysicsandbiology,becauseofthepotentialimpactonmaterialscience,catalysisandmetallo-biochemistry#.ThepreparationandstUdyofpolynuclear,cyanide-bridgedmetalcomplexeshaveattractedconsiderableinterestoverthepastdecades-I3.Cyanide-bridgedpolynuclearcomplexesaresuitablefortheconstructionofsuchdevicestoobtainmoleculescapableofestablishingspe…     

一类三次系统的细奇点

本文研究了具有一个高阶奇点的系统（１,２）,通过在实系统中引入奇点量的概念使焦点量和鞍点量得到统一,并且计算了系统（１．２）的各阶奇点量,证明了这样的系统存在珐多三阶细奇点,而且同时存在细奇点的最大个数是四。当系统是四个细奇点时,它们可能是四个一阶细奇点或四个三阶细奇点。     

二阶扩张状态观测器的误差分析

本文利用分片光滑的Ｌｙａｐｕｎｏｖ函数来进行扩张状态观测器的误差分析,指出了非线性扩张状态观测器有更好的估计精度能力,给出了为提高估计精度扩张状态观测器的参数所满足的条件．     

无解的模糊关系方程的最优近似解

对无解的模糊关系方程给出了最优近似解的定义,证明了最优近似解的存在性,给出了求最优近似解的算法     

激波诱导气流与液幕、液柱相互作用的实验研究

利用激波管对激波诱导气流与液幕、液柱的相互作用进行了实验研究。通过比较发现,这种相互作用下的液体块变形破碎过程与以往对于液滴进行的研究结果很不相同。当激波与液幕相互作用时,阴影照片和直接照相都表明,液幕的变形破碎行为有很强的三维性,较之液滴的变形破坏机理更为复杂,并且在局部区域,初始时刻液幕破碎抛撒的速度相较激波诱导气流速度为快,本文应用一维变截面激波管理论对这一现象进行了理论分析。     

超高压装置的研制及润滑油压缩率测试研究

设计了测量液体压缩率的超高压试验装置。采用自制的传感器测量了超高压腔体内的压力和动密封部件与超高压腔体间的摩擦压力。发现该摩擦压力约为超高压腔实际工作压力的３０％;用差分测量法可消除密封部件和试验装置弹性变形对测量结果的影响;同时测量了几种润滑油的体积压缩率,并用２个数学模型对试验数据进行了处理,消除了系统误差,给出了压缩炫与压力的关系式。结果表明,超高压试验装置结构合理,密封可靠,测试方法先进,     

边坡倾倒变形的形成机制与影响因素分析

本文从边坡倾倒的变形特点出发,分析了倾倒变形的力学机制。在此基础上研究了结构面间距及力学参数对变形的影响。通过含有结构面的岩体的应力,位移以及屈服区的分布特点,讨论了反倾边坡的稳定性问题。     

鲁西南地区红层软岩水岩作用特征与工程应用

鲁西南各断块盆地中广泛分布有侏罗、第三系的紫红色、杂色砂砾岩,岩石呈固结半固结状态,遇水后发生渗透、膨胀、崩解和软化等失稳现象,对煤矿建井及煤矿开采带来重大威胁。本文采用X衍射仪、扫描电镜、压汞仪及液压伺服机等手段进行了红层软岩的物质组成、微孔结构及渗透性的试验研究,探讨了红层软岩的渗透机理及遇水失稳机理,并结合实例进行了工程应用分析。