Phase equilibrium in solutions of star-shaped macromolecules: an improved Okada-Numasawa model

The two-region Okada-Numasawa model for solutions of star-shaped polymers has been improved by means of a change in the integration order and introduction of a concentration-dependent and molar-mass-dependent Flory-Huggins interaction parameter (the second and third approximations of the Flory-Huggins theory). To overcome calculation difficulties, a special algorithm for computing coexistence curves of polymeric systems with an UCST has been used. The agreement between the experimental and calculated coexistence curves for the star-shaped polystyrene (PS)-cyclohexane system has been improved: the difference between T_cs is ∼0.33 K against ∼12 K as given by the original model.     

Concast连铸机自控系统简介

天津钢铁有限公司引进了瑞士Concast公司6机6流方、圆坯连铸机及相关技术，文章简要介绍了Concast连铸机的自动控制系统的特点和功能。     

Parametric circles and spheres

Formulations for parametric circles and spheres in terms of rational Gaussian (RaG) curves and surfaces are introduced. With the proposed formulations, a full circle is generated by interpolating a closed RaG curve to the vertices of an equilateral triangle, and a full sphere is generated by interpolating a closed RaG surface to the vertices of an octahedron with equilateral triangular faces. Generation of circles and spheres in this manner is very intuitive and easy to remember as the weights are all 1 and the nodes are all unique and uniformly spaced.     

基于Matlab语言的液压特性曲线的绘制

Matlab语言强大的运算、仿真能力，被广泛用在液压控制系统中。利用Matlab语言可以进行液压特性曲线的绘制，液压控制系统稳定性的检测，也可以进行液压控制系统的仿真。这里以两个实例，即单、双喷嘴挡板阀压力流量特性曲线的绘制，以及液压转矩放大器系统稳定性的检测，来说明它的强大的功能。     

小纸层析法快速测定^99mTc—HMPAO放射化学纯度

采用小纸层析系统１：１的氯仿／四氢呋喃展开剂分析＾９９ｍＴｃ－ＨＭＰＡＯ的放射化学纯度，并与两个薄层析系统和一个纸层析系统的方法作比较。配对ｔ检验结果表明两种方法测定的放射化学纯度无显著差异；放射化学纯度在７４．２％－９６．４％，小纸层析法与薄层／纸层析法紧密相关，回归公式ｙ＝１．００６ｘ－０．３２３。     

非线性地基上桩结构物空间分析

本文提出了桩结构物－非线性地基空间相互作用分析的迭代法和非线性有限元法。其中，桩基分析用ｐ－ｙ曲线法。结合实际结构物进行了大量的计算及比较分析，成果是令人满意的，可以付诸应用。     

Fabrication of blue-light emission fused-silica substrates by using Si-ion implantation and high-temperature annealing

We fabricated fused-silica substrates which emit blue light by using Si-ion implantation and high-temperature annealing. Photoluminescence peak wavelengths are around 400 nm, and the peak intensities can be remarkable after annealing above 1150 °C.     

An energy dispersive micro X-ray diffractometer based on a combined system of polycapillary optics

An energy dispersive micro X-ray diffractometer based on a combined system of two polycapillary X-ray lenses is designed. The polycapillary X-ray lens in the excitation channel is either a polycapillary parallel X-ray lens (PPXRL) or a slightly focusing polycapillary X-ray lens (SFPXRL). The polycapillary X-ray lens in the detection channel is a PPXRL. At 6.4 keV and 2θ = 141.5°, the total resolution of the diffractometer based on a SFPXRL in the excitation channel and a PPXRL in the detection channel in Δd/d is 4.8%.     

Expressing the equivalence of non‐isothermal and isothermal heat sterilization processes

Currently, the sterility of heat‐processed food and pharmaceuticals is assessed in terms of an F₀ value, based on the equivalence of the heat treatment to an isothermal process at a reference temperature. This F₀ value, however, has a meaning if, and only if, the inactivation kinetics of the targeted spores (or cells) follow a first‐order relationship and the temperature dependence of the D value, the reciprocal of the rate constant, is log‐linear. There is growing evidence that these conditions are not satisfied by many spores, including those of Clostridium botulinum and vegetative cells. Consequently, a replacement for the F₀ value is proposed in the form of a momentary equivalent time at the reference temperature based on the actual survival pattern of the spores, which need not be log‐linear. This equivalent time can be calculated together with the theoretical survival ratio in real time, thus enabling an operator to monitor the lethality of ongoing industrial heat processes. The concept is demonstrated with published survival data of C. botulinum, for which the Weibullian and log‐logistic models served as primary and secondary models, respectively. The safety factor according to the proposed method is in the number of added minutes of processing, beyond the theoretical time needed to reduce the survival ratio of the targeted spores or cells to a level that would produce practical (or commercial) sterility. Copyright © 2006 Society of Chemical Industry