The quantitative analysis of a two-medium mixture using holographic interferometry: the determination of the size corresponding to circular- and rectangular-column voids in a two-medium mixture

The purpose of this paper is to extend the holographic technique to the optical measurement of a two-medium mixture. Assume there exists a void in medium A and the void contains medium B, an experimental technique and the corresponding theories are proposed in this paper, in order to quantitatively determine the size of void in the two-medium mixture. Then the amount of medium B can be determined. An empty glass container was simulated as a void in the mixture. Two different types of glass containers were used and the corresponding theories were derived. The test results show that the errors were in a reasonable range and support the application of holography in the quantitative optical measurement of a two-medium mixture.     

水平流作用下行波对流的成长及周期性重复

数值模拟研究了在极其微弱的水平流动作用下，混合流体Rayleigh-Benard对流系统一 维行波斑图的成长及其时空演化问题.揭示了系统行波对流的周期性现象及其对水平流动强 度的依赖性. 关键词： 时空斑图 混合流体对流 水平流     

Optimization in sample stacking for the measurement of short chain organic acids in serum of natural rubber latex by capillary electrophoresis

It is of interest to measure the short chain organic acid content in natural latex serum, and capillary electrophoresis (CE) has proved to be a good tool for this study. However, for some acids, a higher sensitivity than that provided by the standard methods was needed. Therefore, a stacking effect was optimised and applied both for standards and real samples. Large-volume injection of sample solutions prepared in low conductivity matrices containing 50% acetonitrile (v/v) and 0.5% NaCl (w/v) gave the best results with enhancement factors over 17 and recoveries ranging from 83±14 to 122±4%.     

Controlled polymerizations of 2‐(dialkylamino)ethyl methacrylates and their block copolymers in protic solvents at ambient temperature via ATRP

Very well‐controlled polymerizations of 2‐(dimethylamino)ethyl methacrylate (DMAEMA) and 2‐(diethylamino)ethyl methacrylate (DEAEMA) in aqueous and methanolic solutions via atom transfer radical polymerization (ATRP) at ambient temperature were demonstrated. Poly(DMAEMA) and poly(DEAEMA) of low polydispersity index (PDI) of ～1.07 were obtained using the p‐toluenesulfonyl chloride/CuCl/1,1,4,7,10,10‐hexamethyl‐triethylenetetramine (p‐TsCl/CuCl/HMTETA) system. Excellent control of polymerization was achieved even in pure methanol. This is in contrast with the very poor control of DMAEMA ATRP in methanol reported previously using a different intiator/catalyst/ligand system. The initiator p‐TsCl underwent hydrolysis reaction in aqueous methanolic solutions with a second‐order rate constant of 6.1 × 10^?4 dm³ mol^?1 s^?1 at 25 °C. Both poly(DMAEMA) and poly(DEAEMA) retained almost full chlorine‐functionization at the chain ends. Well‐defined block copolymers of DEAEMA and DMAEMA were successfully obtained by starting with either macroinitiators of DEAEMA or DMAEMA. Other well‐defined diblock copolymers could be prepared using these macroinitiators. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5161–5169, 2004     

氨水混合工质的池内核沸腾换热

对非共沸氨水混合工质的池内核沸腾换热系数在氨浓度为0～100％的范围内进行了测定,并对氨水混合工质的沸腾传热特性进行了分析。利用氨水混合工质独特的热物性,比较了Stephan-Korner,Schlunder和Inoue的双组分混合工质预测关联式,并得出了预测氨水混合工质的池内沸腾换热系数的关联式,其预测精度为±35％。     

Temperature Dependence of the Vibrational Relaxation Rate Constants of CO2 (0001) in Binary Mixtures

The rate constants of intramolecular intermode relaxation of the CO₂ molecule (00⁰1) in pure CO₂ and in binary mixtures with He, Ar, H₂, O₂, N₂, CO, NO, N₂O, and H₂O were measured in the temperature range 300–1000 K by means of a laser-induced luminescence method. It is shown that these relaxation rate constants K for all the gas mixtures investigated increase with increase in the gas temperature in this range; the most efficient in deactivation of the 00⁰1 level are the collisions of CO₂ molecules with H₂O molecules; the mechanisms of relaxation of the 00⁰1 level of CO₂ and their channels depend not only on the temperature but also on the parameters of colliding particles; for each of the colliding partners of the CO₂ molecules there is a certain temperature T _c above which the temperature dependence of K is coordinated with the Landau–Teller dependence, and, moreover, the simpler the structure of the colliding partner of the CO₂ molecule, the higher the temperature T _c. Deviations from these dependences at temperatures T < T _c are attributed to the influence of intermolecular forces of attraction, change of relaxation channels, and formation of molecular clusters. For all the colliding partners of the CO₂ molecules, the interaction radii are determined from the intermolecular potentials of interaction used in the theoretical model.     

Features of the dynamics of hydrothermodynamic perturbations in a stably stratified fluid

The evolution of a certain class of arbitrary-amplitude perturbations in a stratified binary mixture is investigated analytically and numerically. The radical differences between the process in question and the process of hydrostatic adaptation in an ordinary single-component medium are demonstrated. In particular, a long-life “wake“ with nonzero temperature and admixture concentration perturbations that compensate one another in the density field may be formed when the process is completed. The slow process of dissipation of this wake, associated with heat and mass transfer, is investigated.     

Weak Limits for Multivariate Random Sums

Let {Xi, i1} be a sequence of i.i.d. random vectors inRd, and letνp, 0<p<1, be a positive, integer valued random variable, independent ofXis. Theν-stable distributions are the weak limits of properly normalized random sums ∑νpi=1 Xiasνp ∞ andpνp ν. We study the properties ofν-stable laws through their representation via stable laws. In particular, we estimate their tail probabilities and provide conditions for finiteness of their moments.     

Thermodynamic and morphological analysis of eutectic formation of CBZ-l-Asp and l-PheOMe·HCl mixtures

The eutectic melting of a CBZ-l-Asp/l-PheOMe·HCl model mixture was investigated in kinetic, thermal, thermodynamic, rheological, and morphological aspects. From TX-phase diagrams, the eutectic composition was determined to be 0.55 M fraction of CBZ-l-Asp. The highest melting rate and the lowest apparent viscosity in the range of 55-75 °C were obtained at the eutectic composition. Using Arrhenius plots of melting rates and apparent viscosities, minimum activation energies in the range of 60-80 °C were obtained at the eutectic composition, whereas maximum values were attained below 60 °C. At the eutectic composition, the maximum heat of fusion, the lowest excess free energy, and the highest excess entropy values were observed by differential scanning calorimetry (DSC). A highly homogeneous morphology due to rearrangement of molecules was observed in the eutectic mixture via scanning electron microscopy and X-ray diffraction analysis. IR spectra revealed that hydrogen bonding in the mixture increases during eutectic melting.