Inhibition of microbial growth in ready‐to‐eat food stored at ambient temperature by modified atmosphere packaging

This study was undertaken to develop a modified atmosphere package to control microbial growth in ready‐to‐eat (RTE) products stored at ambient temperature. Ethanol and/or limonene associated with modified atmosphere (CO₂ : O₂ : N₂ = 30% : 5% : 65%) was used to inhibit the growth of total air‐borne microorganisms and Escherichia coli in RTE products stored at 25°C. The results indicated that 0.05% ethanol vapour in the headspace was effective to inhibit the growth of air‐borne microorganisms and E. coli at 25°C for 72 h in a model study, and the effectiveness was related to ethanol content. Both 73 ppm limonene and 0.05% ethanol vapour enhanced the bacteriostatic effect of modified atmosphere in RTE sushi roll products, and no off‐flavour was detected using this formulated gas; however, no significant inhibitory effect was observed for RTE cold noodle products. This study concludes that combinations of carbon dioxide, ethanol or limonene vapours are effective to inhibit microbial growth in RTE food at ambient temperature, and the outcome may be due to the hurdle effect. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis of amphiphilic magnetic microspheres by dispersion copolymerization of styrene and poly(ethylene oxide) macromonomer

Amphiphilic magnetic microspheres ranging in diameter from 5 to 100 µm were prepared by dispersion copolymerization of styrene and poly(ethylene oxide) vinylbenzyl (PEO‐VB) macromonomer (MPEO) in the presence of Fe₃O₄ magnetic fluid. The effects of various polymerization parameters on the average particle size were systematically investigated. The average particle size was found to increase with increasing styrene concentration and initiator concentration. It also increased with decreasing stabilizer concentration and molecular weight of MPEO. The content of the hydroxyl groups localized in the microspheres ranged from 0.01 to 0.2 mmol g^?1. © 2003 Society of Chemical Industry     

Na+、K+离子交换对Co-Mo/MCM-41加氢脱硫催化剂的影响

 用偏硅酸钠和正硅酸乙酯作硅源制备了MCM-41（分别记作MCM-41(S)和MCM-41(T)）分子筛，并用Na₂C₂O₄和K₂C₂O₄对MCM-41(S)进行了碱金属离子交换改性。以质量分数0.8 %的二苯并噻吩（DBT）的十氢萘溶液为模型化合物，考察了不同MCM-41担载的Co-Mo硫化物催化剂对DBT的加氢脱硫反应性能。结果表明，MCM-41担载的Co-Mo催化剂加氢活性较低，DBT主要通过直接脱硫反应路径脱硫。其活性顺序为：Co-Mo/MCM-41(T)>Co-Mo/MCM-41(S)>Co-Mo/MCM-41(K)>Co-Mo/MCM-41(Na)。UV-Vis结果表明，部分Co与MCM-41(S)中少量Al发生相互作用，生成了CoAl₂O₄，是造成Co-Mo/MCM-41(S)活性降低的重要因素。而在Co-Mo/MCM-41(K)和Co-Mo/MCM-41(Na)中，除CoAl₂O₄物种之外，碱金属的引入还促进了Co₃O₄物种的形成，使其活性进一步降低。     

声波测井换能器激发响应实验研究

声波测井换能器的激发响应由换能器振动时所表现出来的动态阻抗和激发电路参数决定。而换能器的动态（阻抗）参数随压电晶体及其装配方式（力学边界条件）改变。为了测量换能器动态参数的影响，采用声波测井仪器常用的压电晶体和升压变压器，通过改变激发脉冲宽度和直流电压进行了实验，结果发现：在换能器两端的瞬态响应中，一共有三个二阶网络响应，分别对应于不同的频率。最低的一个影响声波测井波形的基线、与换能器主频接近的一个决定激发效率以及电路与压电晶体之间的匹配关系，是激发电路设计中比较关键的，其参数可以通过导纳圆测量仪器得到。     

新设备技术在催化裂化装置上的应用

文章介绍了近年来在催化裂化装置上应用的新设备、新技术,如BY型旋风分离器、BSX型旋分式三级旋风分离器、上下拱型三级旋风分离器、下拱型三级旋风分离器、SHS“自蔓延”技术、SWY外取热器、BWJ型喷嘴、自流浇注料、Actehem高耐磨衬里、弓形钢丝纤维、侧拉环锚固钉、分体可拆人孔等的结构特点及实际应用情况。     

一种PD雷达动目标模拟与微波测控系统

介绍了一种基于PC／104总线，具有GPIB程控功能，采用无内部微波源体制，通过在雷达载频上调制多普勒频率模型目标速度信息，延迟雷达发射机触发脉冲模拟目标距离信息并具有微波功率精确定标与衰减功能的PD雷达动目标模拟与微波测控系统。     

A decision support system for interactive decision making - Part II: analysis and output interpretation

For pt.I see ibid., p.42-55 (2003). The development of a comprehensive decision support system, GMCR II, for the systematic study of real-world interactive decision problems is presented. The companion paper (Part I), discusses how GMCR II elicits, stores, and manages conflict models; here (Part II), the focus is on GMCR IIs analysis and output interpretation subsystems. Specifically, this paper describes the powerful and efficient analysis engine contained in GMCR II, its informative output presentation and interpretation facilities, and a number of follow-up analyses. Furthermore, an illustrative case study is used to demonstrate how GMCR II can be conveniently applied in practice.     

Finite element analysis of advanced multilayer capacitors

We establish a systematic methodology to design and analyse electromagnetic components such as advanced multilayer ceramic capacitors (MLCCs) using the finite element (FE) method. We employ a coupled formulation to compute the interaction between the electric and magnetic fields. Unlike a linear distribution of current assumed in the circuit model, an accurate electrostatic solution to model the entire advanced MLCCs (4 × 4 × 27 = 432 cells) is presented. The FE solution is used to compute the lumped parameters for a range of frequencies. These lumped parameters are then used to compute the parasitic elements of the MLCCs. We introduce two algorithms to efficiently analyse the behaviour of a capacitor with changing frequency. The lower frequency (much below the self‐resonant frequency of the capacitor) algorithm separates the effect of the electric and magnetic fields and reduces the computational effort required to solve the FE problem, whereas, the high‐frequency algorithm couples the effect between the electric and the magnetic fields. We use these algorithms in conjunction with a new multiple scale technique to effectively determine the small values of R, L and C in MLCCs. The formulation, the implementation, and the numerical results demonstrate the efficacy of the present FE formulation and establish a systematic methodology to design and analyse advanced electromagnetic components. Copyright © 2003 John Wiley & Sons, Ltd.     

Mass Transfer in a Flat Gas/Liquid Interface using non‐Newtonian Media

Gas/liquid mass transfer has been investigated using a stirred vessel gas/liquid contactor using non‐Newtonian media and carbon dioxide as absorbent and gas phase, respectively. The volumetric mass transfer coefficients at different operational variables have been determined. Non‐Newtonian media (liquid phase) were prepared as aqueous solutions of sodium carboxymethyl cellulose salt. The influence of the rheological properties, polymer concentration, stirring rate, and gas flow rate on mass transfer was studied for these liquid phases. Kinematic viscosity and density experimental data were used to calculate the average molecular weight corresponding to the polymer employed. The Ostwald model has been used to fit the rheological behavior of aqueous solutions of the polymer employed as absorbent phase. Reasonably good agreement was found between the predictions of the proposed models and the experimental data of mass transfer coefficients.     

Breaking a remote user authentication scheme for multi-server architecture

Lin et al., (2003) proposed a remote user authentication scheme for multi-server architecture. In this paper, we breaks this scheme by giving an attack. Our attack allows an adversary to impersonate any user in the system, as long as a single authentication message of that user is observed.