Additivity Factors in the Binding of the Diethyltin(IV) Cation by Ligands Containing Amino and Carboxylic Groups at Different Ionic Strengths

Complex formation constants were determined potentiometrically (by a ISE-H⁺, glass electrode) in the systems, M²⁺ – L^z – H⁺ [M²⁺ = (C₂H₅)₂Sn²⁺, L^z = malonate, glycinate and ethylenediamine] at t = 25 ^∘C and 0.1 mol-L⁻¹≤ I/ ≤ 1 mol-L⁻¹ in NaCl_aq (0.1 mol-L⁻¹ ≤ I ≤ 0.75 mol-L⁻¹ for the ethylenediamine system). Thermodynamic values of formation constants, at infinite dilution, are [± 95% confidence interval, ^Tβ_pqr refer to the equilibrium, pM²⁺ + qL^z + rH⁺ = M_pL_qH_r^(2+z+r)]: for malonate, log₁₀ ^Tβ₁₁₀ = (5.47 ± 0.10); for glycinate, log₁₀ ^Tβ₁₁₀ = (9.54 ± 0.08), log₁₀ ^Tβ₁₁₁ = (12.97 ± 0.10); and for ethylenediamine, log₁₀ ^Tβ₁₁₀ = (10.47 ± 0.10), log₁₀ ^Tβ₁₂₀ = (16.17 ± 0.12) and log₁₀ ^Tβ₁₁₁ = (15.46 ± 0.10). The dependence on ionic strength of the formation constants was modeled by a simple Debye–Hückel type equation and by the SIT approach. By analyzing the stability of the species in the three different systems we found a simple additivity rule that can be expressed by the relationship: log₁₀ K = 6.46 n_N + 3.96 n_O − 0.60 (n_N²+ n_O²), with a mean deviation, ε(log₁₀ K) = 0.15 (K = equilibrium constant for the interaction of the organometal cation with the unprotonated or protonated ligand, n_N = number of amino groups and n_O = number of carboxylic groups of the ligand(s) involved in the formation reaction of complex species).     

普鲁士兰修饰碳黑微电极同时微分伏安法测定多巴胺和抗坏血酸

将含有1.0%普鲁士蓝的碳黑与固体石蜡按2.5∶1(质量比)混合后装入φ0.2mm的石英毛细管中,在其上端插入一铂丝并抛光后即制成普鲁士蓝修饰碳黑微电极.对多巴胺(DA)及抗坏血酸(VC)在此电极上的电化学行为及应用此电极测定两组分的最佳条件进行了研究,在定量测定中采用二次微分线性扫描伏安法.在最佳条件下,DA与VC的峰电流(i″p)分别与各自的浓度保持如下线性关系DA为4.0×10-6～8.0×10-4mol·L-1,VC为6.0×10-5～1.0×10-3mol·L-1;检出限(3σ)依次为2.0×10-6mol·L-1及1.0×10-5mol·L-1.应用此方法分析了3种含DA及VC的混合溶液,测得结果的相对标准偏差(n=8)依次小于2.0%及3.0%,回收率范围依次为96.5%～101.0%及95.0%～102.5%.     

Excess heat capacities of ternary systems containing chlorobenzene or chloronaphthalene

Densities and heat capacities of ternary systems were determined at 25°C. The ternary systems consisted of: a polar molecule (component 1) + a mixture of alkanes (components 2 and 3) of different sizes and shapes. Five such systems were studied: chlorobenzene + cyclohexane + n-heptane; chlrobenzene + cyclohexane + n-hexadecane; chlorobenze + cyclohexane + isooctane; chlorobenzene + isooctane + n-heptane; 1-chloronaphthalene + isooctane + n-heptane. The excess molar volumes and heat capacities were obtained along dilution lines by component 1 (chlorobenzene or 1-chloronaphthalene) of mixtures of components 2 and 3 (at fixed component 2 mole fraction X₂). Unexpectedly the excess heat capacities C _p1(23) ^E of the pseudo-binaries {1+(2+3)} do not always fall between the two (limiting) curves of C _p12 ^E and C _p13 ^E corresponding to the two binaries {1+2} and {1+3}. Instead, especially for {chlorobenzene + cyclohexane + an n-alkane} the C _p1(23) ^E curves are displaced toward less negative values, even beyond the limiting values corresponding to the binaries. This correlates semi-quantitatively with the negative C _p23 ^E of the binary {2+3}.Presented at the Symposium, 76^th CSC Congress, Sherbrooke, Quebec, May 30-June 3, 1993, honoring Professor Donald Patterson on the occasion of his 65^th birthday.     

安力农的极谱测定及其电化学行为

在ｐＨ５．６，０．１５ｍｏｌ／Ｌ磷酸盐缓冲溶液（ＰＢＳ）中，得到了安力农的灵敏极谱吸附波，波的二阶导波高在２×１０＾－８～８×１０＾－６ｍｏｌ／Ｌ范围内与安力农的浓度成直线关系，检测下限为１×１０＾－８ｍｏｌ／Ｌ，测定出电极过程的电子传递系数ａ＝０．４３，表面电极反尖速率常数ｋｓ＝３．３ｓ＾－１，安力农在汞电极上的吸附遵从Ｌａｎｇｍｕｉｒ等温式，测得其吸附系数β＝８．１×１０＾５。     

RELATIONSHIPS BETWEEN X—H STRETCHING OVERTONE FREQUENCIES AND BOND LENGTHS/BOND ANGLES

A relationship between the X-H (X = N, O, C, and so on) equilibrium bond length in a Morse oscillator and the X-H stretching overtone frequency shifts is obtained theoretically. We use the equation to discuss the empirical linear relationships that have been proposed for heterocyclics, alkanes and fluorinated benzenes. On the other hand, a unified relationship between the X-H bond angles and the experimental quantities (ω(?) and the coupling strength λ) is also presented for XH2, XH, and XH4 molecules or molecular fragments. Calculations of X-H bond angles for a number of molecules show that the results from our equations are in excellent agreement with the experimental values. Also we can extract the information of relative magnitude of bond coupling force field.     

Analysis of the contribution of skeletal vibrations to the heat capacity of linear macromolecules in the solid state

Automatic computer programs are developed to calculate one- two-, and three-dimensional Debye functions. Prior tables of these functions are critically reviewed. Also, strategies are derived to calculate Debye temperatures from heat capacities. Both, simple three-dimensional Debye analyses and Tarasov analyses were carried out on 35 linear macromolecules. The experimental heat capacities for these analyses were collected in the ATHAS data bank. It is shown that the skeletal heat capacity of linear macromolecules is often best represented by only two vibrations per chain atom. For most of the all-carbon chain macromolecules the intramolecular skeletal heat capacity can be given by C_vs=D₁[520 (28/MW)^1/2] whereMW is the molecular mass andD ₁ represents the one-dimensional Debye function. Polyoxides show a higher intramolecular theta temperature, but a lower intermolecular theta temperature. Double bonds and phenylene groups in the chain increase the intramolecular theta temperature.Dedicated to Prof. Dr. F. H. Müller.On leave from the Lumumba Peoples' Friendship University, Moscow, USSR.     

Effect of thermal history on crystallization and melting behaviour of lldpe

In this paper two LLDPE samples with their own structural parameters were studied by means of DSC. Experimental results show that DSC was good for revealing slight structural difference between these two samples. Furthermore, the effect of thermal history on crystallization and melting behaviour of LLDPE was observed clearly through varying conditions of thermal treatment.

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Zusammenfassung Mittels DSC werden zwei LLDPE-Proben mit ihren eigenen Strukturparametern untersucht. Die Versuchsergebnisse zeigen, da\ sich DSC gut eignet, um gering fügige Unterschiede dieser zwei Proben nachzuweisen. Weiterhin wurde unter verschiedenen Bedingungen der Einflu\ der thermischen Vorgeschichte auf das Kristallisations-und Schmelzverhalten von LLDPE untersucht.

     

On the regulator problem for linear degenerate control systems

In this paper, we study the finite-time regulator problem for linear, autonomous, degenerate systems, i.e., systems described by the differential equation with det(K)=0. Two investigations of the regulator problem are presented, which depend on the quadratic cost associated with the differential equation.This work was performed under the auspices of the National Research Council of Italy, Gruppo Nazionale per l'Analisi Funzionale e le Sue Applicazioni, Rome, Italy.     

On guaranteed stability of uncertain linear systems via linear control

This paper addresses the problem of stabilizing an uncertain linear system. The uncertaintyq(·) which enters the dynamics is nonstistical in nature. That is, noa priori statistics forq(·) are assumed; only boundsQ on the admissible variations ofq(·) are taken as given. The results given here applied to so-called matched systems differ from previous results in two ways. Firstly, the stabilizing control in this paper is linear; for this same class of problems, many of the existing results would require a nonlinear control. Furthermore, those results which do in fact yield linear controls are only valid when a certain matrix (q) (formed using the given data) is negative definite for allq Q. In contrast, the theory given here only requires compactness of the bounding setQ. Secondly, we show that the so-called matching conditions (used in earlier work) can be generalized so as to encompass a larger class of dynamical systems.This research was supported by the US Department of Energy under Contract No. ET-78-S-01-3390.     

Applications of homemade kit in mutation detection of genes

With the accomplishment of Human Genome Project (HGP), single nucleotide polymorphism (SNP) and mutation detection in human genome are becom-ing a new researching focus. These researches can help us to understand the phenotype diversity of indi-vidual, disease susceptibility and drug resistance of different colonies. Traditional method used for muta-tion detection is slab gel electrophoresis, which re-mains labor-intensive and time-consuming because of the requirement of radioactivity or te…