现行RPM管道标准中存在的若干问题

本文就现行RPM管道标准中存在的若干问题进行了研讨。     

Issues in the Processing of Cuprate Ceramic Superconductors

A number of the important issues in the processing of dense, superconducting ceramics are addressed and illustrated with examples drawn from our studies of the processing of yttrium barium cuprate. Among the phenomena affecting the attainment of dense, fully superconducting materials are those common to the processing of other ceramics, namely, control of composition, prevention of microcracking, adequate time for the decomposition, and escape of intermediaries prior to surface densification (the so-called "binder burn-off" problem). Additional requirements include the necessity to ensure complete oxygenation throughout the microstructure for full volume superconductivity and the control of texture development for maximizing the attainable transport critical current density. On the basis of the processing issues described, it is concluded that the optimum microstructure is one having finescale, interconnected porosity (to ensure escape of carbonate-like species and subsequent, rapid oxygenation) with a fine grain size (∼1 μm) to avoid microcracking.     

渔杆漆在施工中易出现的问题

简述渔杆漆施工中所用的工具和施工方法 ,施工中易出现的弊病、产生原因及解决方法     

Modelling risks in disease mapping

In this article, we propose a strategy of analysis of mortality data with the aim of providing a guideline for epidemiologists and public health researchers to choose a reasonable model for estimating mortality (or incidence) risks. Maps displaying the crude mortality rates or ratios are usually misleading because of the instability of the estimators in low populated areas. As an alternative, many smoothing methods have been presented in the literature based on Poisson inference. They account for the extra-Poisson variation (overdispersion), frequently present in the homogeneous Poisson model, by incorporating random effects. Here, we recommend to test for the potential sources of extra-Poisson variation because, depending on them, the models which fit better the data may be different. Overdispersion can be mainly due to spatial autocorrelation, unstructured heterogeneity or to a combination of these two, and also, when studying very rare diseases, it can be due to an excess of zeros in the data. In this article, different situations the analyst may encounter are detailed and appropriate procedures for each case are presented. The alternative models are illustrated using mortality data provided by the Statistical Institute of Navarra, Spain.     

Capillary forces between two solid spheres linked by a concave liquid bridge: Regions of existence and forces mapping

This article focuses on the capillary interactions arising when two spherical particles are connected by a concave liquid bridge. This scenario is found in many situations where particles are partially wetted by a liquid, like liquid films stabilized with nanoparticles. We analyze different parameters governing the liquid bridge: interparticle separation, wetting angle and liquid volume. The results are compiled in a liquid volume‐wetting angle diagram in which the regions of existence (stability) or inexistence (instability) of the bridge are outlined and the possible maximum and minimal particle distances for which the liquid bridge may be found. Calculations of the capillary forces discriminate those conditions for which such force is repulsive or attractive. The results are plotted in form of maps that allow an easy understanding of the stability of a liquid bridge and the conditions at which it may be produced for the two particle model. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

球形锌粉制备过程中的安全问题

球形锌粉被广泛应用于生物医药、海洋工程、电子电池、航空航天、高速铁路等行业,其粒度、纯度、球晶表面积、整洁度、松装比等指标决定着品质的优劣,同时也对制备工艺和安全问题提出了不同要求。对于粒度小于47μm规格的球形锌粉,因其粒度细、挥发性好、活性强,在制备过程中经常会发生因规划建设不合理、设备设计不合理、管理不到位、人员操作不当等而导致的火灾和爆炸,尤其在分级过程中若治理不当会出现粉尘爆炸,系统的能量转化为机械功以及光和热的辐射,会产生很强的破坏力,引发灾难事故。如何防火防爆是在球形锌粉制备过程中的重要研究课题。     

商战中的“不等式”

提出了国内企业在我国入世后,在新一轮商战中,在观念上应解决的八个方面的问题("不等式").     

商战中的“不等式”

提出了国内企业在我国入世后，在新一轮商战中，在观念上应解决的八个方面的问题（“不等式”）。     

水溶液的冷冻干燥问题(英文)

Freeze drying or lyophilization of aqueous solutions is widely used in pharmaceutical industry.The increased importance of the process is gaining a worldwide interest of research.A growing body of literature has demonstrated that the scientific approach can result in improved product quality with minimum trial and error empiricism.Formulation and process development need a systematical understanding of the physical chemistry of freezing and freeze drying,material science and mechanisms of heat and mass transfer.This paper presents an overview on freeze drying of aqueous solutions based on publications in the past few decades.The important issues of the process are analyzed.     

压力容器设计中几个问题的探讨

依据相关标准规范的规定,参照国外标准的相应规定,结合设计工作实践,对压力容器设计中安全系数,最高允许工作压力两个问题进行探讨。     

高性能纤维模量表征中的几个问题

采用万能材料试验机对超高相对分子质量聚乙烯纤维（SK75型）和芳纶（Twaron2000型）两种样品的单丝、复丝模量进行了表征。研究发现,单丝的模量测定时,启动时拉伸夹具的惯性是初始模量误差的主要来源。样品处于松弛状态,使预张力为零,可以准确地测量样品初始模量;选取加载预张力的方法,应变取值范围设定为0．5％～1．5％时可以克服启动力的影响,得到合理的结果。在复丝测定时启动力可以忽略。测试时需要加捻的复丝样品,不合理的应变取值范围是误差主要来源,应变取值范围设定为0．1％～1．0％时可以得到合理的结果。     

离子液体工业化面临的几个问题

结合离子液体研究的发展趋势,提出离子液体产业化面临的系列问题,如离子液体生产工艺的柔性化设计、离子液体系列产品的标准、离子液体的应用与合成的专利申请及离子液体产业化过程中离子液体的回收再利用等技术问题。     

我国化工产业反倾销问题探讨

阐述了我国加入WTO后化工产业反倾销的现状，介绍和解析了化工企业提起反倾销调查的基本条件和基本程序，提出了运用反倾销规则维护我国化工产业权益的对策建议。     

亥姆霍兹函数讲授中注意的几个问题

亥姆霍兹函数是物理化学中常用的一个重要物理量,在各种教材中均有介绍,而对亥姆霍兹函数的理解,各教材中提及较少,对于初学物理化学的同学来说,存在一定的难度。根据这几年的教学经验,本文就亥姆霍兹函数的理解进行了讨论,希望对学习物理化学的同学有所帮助。     

我国化工产业反倾销问题探讨

阐述了我国加入WTO后化工产业反倾销的现状,介绍和解析了化工企业提起反倾销调查的基本条件和基本程序,提出了运用反倾销规则维护我国化工产业权益的对策建议.     

甲醇汽油的应用及设计中需考虑的重点问题

随着我国经济的高速发展,能源消费也在不断增长,能源日趋紧张,寻找汽车清洁能源已经成为我国的一项基本国策。本文通过对甲醇汽油的发展现状分析,简单介绍了甲醇汽油的理化性质和目前甲醇汽油的主要生产工艺。提出了该类项目在设计中应重点注意的几个方面,例如火灾爆炸危险性、毒性、环保等方面,并预计甲醇汽油的发展前景。     

Physical mapping of fluidization regimes—the EMMS approach

The existence of multiple regimes of distinctive flow structure is a remarkable characteristic of fluidization, which is far from being physically interpreted under a unified approach. The energy minimization multi-scale model (Particle-Fluid Two-Phase Flow, the Energy Minimization Multi-Scale Method, Metallurgical Industry Press, Beijing, 1994) is potentially such an approach in which the inclusion of stability criteria enables the prediction of heterogeneity and non-linear behaviors in fluidized beds. However, fully analytical solution of the model is impossible so far, and numerical solutions have resorted to general optimizing software. Therefore, the detailed characteristics of the solutions and their theoretical implications have not been fully explored. In this paper, we have achieved this by a rigorous numerical approach and by retrieving all missing roots, which leads to physical mapping of fluidization regimes. The model is also extended to unsteady conditions with acceleration and simplified by employing a single stability criterion, which identifies choking as a jump between two branches of the stable solution. Calculations based on this version are in reasonable agreement with measurements on bench, pilot and commercial scale circulating fluidized beds.