THE TRANSFER BEHAVIOUR OF SOME CATIONS AT WATER／NITROBENZENE INTERFACE BY SEMIDIFFERENTIAL CYCLIC VOLTAMMETRY

The transfer of Sr~(2+) and Ba~(2+) ion, facilitated by 18-Crown-6 present in the aqueous phase, and of succinylcholine ion at w/nb interface were investigated by semi-differential cyclic voltammetry. A good polarographic curve of succinylcholine ion dissolved in water was obtained in the system of 0.01 mol/l LiCl (w)——0.01 mol/l TBATPB (nb). The peak current is directly proportional to the concentration of SC~(2+) ion. It can be used for the determination of SC and the detection limit is 1.05×10~(-5) mol/l.The apparent D~w and D~(nb) have been estimated. The transfer of Sr~(2+) and of Ba~(2+) at the interface are facilitated by 18-Crown-6 present in the aqueous phase and the peak current is directly proportional to the concentration of 18-Crown-6 in water. This method can be used for the determination of the complexing agent and for the stability constant of the complex formed in the aqueous phase.All the experimental results are in keeping with the theoretical.     

杂环基二硅烷的合成与波谱表征

由2—噻吩基锂和N-吡咯格氏试剂分别与氟五甲基二硅烷反应,制得了2—噻吩基、五甲基二硅烷(Ⅰ)和N-吡咯基五甲基二硅烷(Ⅱ)。两种二硅烷都是无色液体。Ⅰ在室温下空气中是稳定的,Ⅱ在空气中逐渐转变成绿褐色。元素分析,IR,~1H MR和MS分析证实了其结构。Ⅰ和Ⅱ的最大紫外吸收峰分别为242.0nm和220.1nm。     

偏最小二乘紫外分光光度法同时测定萘，1－甲基萘和蒽

用偏最小二乘法（ＰＬＳ）进行校正和预测，不经分离同时测定了混合体系中的萘，１－甲基萘和蒽。萘，１－甲基萘和蒽的浓度分别在０～２８ｍｇ／Ｌ，０～４０ｍｇ／Ｌ和０～４０ｍｇ／Ｌ的浓度范围服从比耳定律。对合成样品中这三种组分进行分析，结果令人满意。     

关于C_(11)A_7·CaF_2稳定性的研究

本文采用X射线衍射分析方法,研究了影响C_(11)A_7·CaF_2稳定性的因素,结果表明C_(11)A_7·CaF_2在1450℃以内,能够稳定存在;Mgo,K_2O对C_(11)A_7·CaF_2稳定性没有影响;Na_2O、P_2O_5和CaO能与C_(11)A_7·CaF_2发生反应、分别生成少量NC_6A_3、Ca_5F(PO_4)_3和C_3A,但在硅酸盐水泥熟料的正常煅烧制度下,反应程度较低,对C_(11)A_7·CaF_2稳定性不大.熟料中铝酸盐相存在的形式,主要取决于氟在熟料中的分布,CaF_2掺量较低,温度超过1350℃,C_(11)A_7CaF_2消失,生成C_3A;CaG_2掺量较高时,温度高达1450℃,熟料中的铝酸盐相仍为C_(11)A_7·CaF_2,而不生成C_2A.     

科斯社会成本问题与政府管制的效率实现

科斯在其社会成本一文中提出经济行为具有相互性,并很好地将交易成本理论运用在经济行为中,通过交易成本为零的理想世界到交易成本为正的现实世界进行条件转换分析,提出了外在性存在的根源及解决途径主要包括自愿协商(市场)、企业、政府和法律四种;提出由市场解决不好的问题,不一定政府就解决的很好;提出应从社会净收益最大化的角度来看,关键在于避免较严重的损害的观点,即如何使损失最小化或使社会经济运行效率最大化。他的这些思想,使经济学家注意到了交易成本的各种后果,大大地提高了经济的解释力。为政府更有效地进行管制提供了理论支撑。     

浅议山西省农机事故的成因与对策

讨论了山西省农机事故的基本特征，分析了这些农机事故发生的主要原因，提出了预防和降低农机事故的主要措施。     

Ruin Probability with Variable Premium Rate and Disturbed by Diffusion in a Markovian Environment

We consider a risk model with a premium rate which varies with the level of free reserves. In this model, the occurrence of claims is described by a Cox process with Markov intensity process, and the influence of stochastic factors is considered by adding a diffusion process. The integro-differential equation for the ruin probability is derived by a infinitesimal method.     

Newton's Easy Quadratures ``Omitted for the Sake of Brevity'

In the 1687 Principia, Newton gave a solution to the direct problem (given the orbit and center of force, find the central force) for a conic-section with a focal center of force (answer: a reciprocal square force) and for a spiral orbit with a polar center of force (answer: a reciprocal cube force). He did not, however, give solutions for the two corresponding inverse problems (given the force and center of force, find the orbit). He gave a cryptic solution to the inverse problem of a reciprocal cube force, but offered no solution for the reciprocal square force. Some take this omission as an indication that Newton could not solve the reciprocal square, for, they ask, why else would he not select this important problem? Others claim that ``it is child's play' for him, as evidenced by his 1671 catalogue of quadratures (tables of integrals). The answer to that question is obscured for all who attempt to work through Newton's published solution of the reciprocal cube force because it is done in the synthetic geometric style of the 1687 Principia rather than in the analytic algebraic style that Newton employed until 1671. In response to a request from David Gregory in 1694, however, Newton produced an analytic version of the body of the proof, but one which still had a geometric conclusion. Newton's charge is to find both ``the orbit' and ``the time in orbit.' In the determination of the dependence of the time on orbital position, t(r), Newton evaluated an integral of the form ∫dx/x <sup>n</sup> to calculate a finite algebraic equation for the area swept out as a function of the radius, but he did not write out the analytic expression for time t = t(r), even though he knew that the time t is proportional to that area. In the determination of the orbit, θ (r), Newton obtained an integral of the form ∫dx/√(1−x<sup>2</sup>) for the area that is proportional to the angle θ, an integral he had shown in his 1669 On Analysis by Infinite Equations to be equal to the arcsin(x). Since the solution must therefore contain a transcendental function, he knew that a finite algebraic solution for θ=θ(r) did not exist for ``the orbit' as it had for ``the time in orbit.' In contrast to these two solutions for the inverse cube force, however, it is not possible in the inverse square solution to generate a finite algebraic expression for either ``the orbit' or ``the time in orbit.' In fact, in Lemma 28, Newton offers a demonstration that the area of an ellipse cannot be given by a finite equation. I claim that the limitation of Lemma 28 forces Newton to reject the inverse square force as an example and to choose instead the reciprocal cube force as his example in Proposition 41. (Received August 14, 2002) Published online March 26, 2003 Communicated by G. Smith     

整机老炼条件的优化设计

本文通过工程实例，阐述如何利用现有信息来设计产品的老炼条件，以使它在保证产品达到规定可靠性的前提下尽量节省成本     

粘合衬对服装舒适性影响的研究

探讨了粘合衬与粘合工艺对服装透气性、透湿性及透水性影响的规律。得出服装的舒适性虽由面料决定,但辅料(粘合衬)的影响也不可忽视。粘合衬的涂胶种类,粘合衬本身的透气性与透湿性,以及非织造粘合衬底布的单位重量,机织粘合衬底布的覆盖系数等,均对服装舒适性有影响,从而为衬料的选择,以及粘合工艺参数的设定,提供了依据。