快干涂料铸渗法获得铸件表面复合层的研究

对快干涂料法铸渗工艺进行了研究。查明了影响铸件表面复合层质量的主要工艺因素,确定了最佳工艺参数,为生产实践提供了依据。     

钢结硬质合金材料的研究进展

介绍了钢结硬质合金的性能特点及制备工艺,简述了近年来在钢结硬质合金领域开展的研究与取得的进展,对钢结硬质合金的应用进行了分类归纳,展望了其发展前景。     

Advanced experimental and numerical methods for the analysis of the dynamic forming press behavior

Numerical simulations are used to estimate the dynamic behavior of new concepts of forming presses as well as to improve the dynamic properties of existing machines. These simulations are to be parametrized with appropriate values in order to yield most accurate results. In many cases neither the way of building up the simulation model for the specific problem nor an appropriate method for gathering the needed date are given in advance. Regarding these facts this paper intends both to characterize the way of building up complex simulation models by using basic simulation modules and to describe methods for the identification of the needed parameters that work even under conditions that hitherto made parameter identifications impossible or at least very time-consuming. In this context recent developments in simulating press dynamics will also be characterized as new modal analysis methods that are not yet established in the field of forming technique. The research activities were financed by the European Research Association for Sheet Metal Working.     

表面技术用新型加热与干燥设备

夜面涂装加热与干燥设备是近年来开发的节电新技术,可较传统热风炉或一般远红外炉节电15～40%,炉内上下温差3～8℃。文章提出用系统优化的原理和方法对乳白石英管低温辐射加热进行研究,设计中采用辐射密度分布法和部份功率控制法。     

A New Process to Make a Porous PTFE Structure from Aqueous PTFE Dispersion with the Help of Hydrogel

A novel method to make a porous material having relatively large cell diameter (200–300 m), which consisted of mainly poly(tetrafluoroethylene) (PTFE), was developed from aqueous PTFE dispersion by using the characteristics of hydrogel with the addition of carbon nanofiber (CNF). The porous material was produced as follows: firstly, an aqueous agar gel containing PTFE and CNF was prepared; secondly, the gel was freeze-dried; thirdly, the dried gel was heat-treated at 400°C where the agar was almost decomposed and PTFE became molten. The porous material showed electric conductivity (about 50 ), high porosity (about 96 vol%), and relatively uniform cell structures without shrinkage during freeze drying and heat treatment. While the method without CNF resulted in large shrinkage during heat treatment, meaning that CNF prevented the shrinkage. It was explained by the idea that the existence of rigid CNF, which was dispersed in the cell wall, prohibited the shrinkage of PTFE during heat treatment. It was unexpectedly found by SEM analysis that the porous materials had another macro-porous structure inside the cell wall, suggesting that the developed materials had a double porous structure.     

气液固三相床中合成甲醇与二甲醚

叙述了气液固三相催化反应技术的主要特点和应用领域，并着重介绍了三相床合成甲醇和二甲醚的试验研究内容和成果。     

利用微波介电加热和微波干燥水解法制备TiO2微粒

利用微波介电加热和微波干燥条件下TiCl4直接水解的方法制备出平均尺寸为40m，粒径分布窄，均为球形且形态均一，团聚较少，金红石型的TiO2纳米粒子，其内部品粒平均大小为17nm。而传统加热和干燥条件下形成的纳米微粒平均为60nm，粒经大小不均一，形态较不规则，团聚严重。微波加热和干燥方法具有清洁、快速均匀高效、环境友好的优点，推广前景良好。TiCl4水解法经济便利，适于工业化生产。     

Energy Aspects in Drying

The energy performance of a dryer and a drying process is characterized by various indices such as volumetric evaporation rate, steam consumption, unit heat consumption and energy (thermal) efficiency. Of all indices, energy efficiency is the most frequently quoted, in technical specifications. A thorough analysis of available information, including the Handbook of Industrial Drying, points to the inconsistency of terminology, definition and data interpretation. Thus, reported data on energy efficiency vary significantly and frequently contradict both drying theory and industrial practice. To establish a common platform to deal with energy issues, this article provides a concise overview of the most common definitions of energy efficiency, along with a critical review of the published data. A need for energy audit and benchmarking is pointed out. To eliminate shortcomings of the energy efficiency as a lumped parameter, and to allow analysis of energy consumption over time (batch drying) or distance (continuous drying), instantaneous and cumulative indices are proposed. Using these indices, the energy performance of selected dryers is examined, and possible modifications to dryer design and operating parameters are indicated in order to reduce the overall energy consumption.     

减缩抗裂型混凝土超塑化剂的性能及其作用机理

开发了一种新型的减缩抗裂型超塑化剂(shrinkage-reducing and anti-cracking polycarboxylate-based superplasticizer,SRPCA),掺量为水泥质量的0.2%时,减水率可达22.3%,且增强效果明显.和掺传统萘系减水剂的混凝土相比,掺SRPCA的混凝土90d的自收缩率和干燥收缩率分别降低了52.1%和44.9%.平板和圆环开裂实验证实:SRPCA大大提高了混凝土的抗裂能力.SRPCA的减缩抗裂效果基本接近减缩剂掺量为胶凝材料总质量2%的减缩抗裂效果,但SRPCA的掺量不到复掺萘系减水剂和减缩剂的1/10.     

多层水平气流带式干燥机的数学模型

根据干燥传质传热学原理和干燥动力学特性，建立了水平气流带式干燥机干燥过程的数学模型。该模型可以预测干燥机合理的通风道高度、带翻转最佳时间和热风风速等。为优化多层带式干燥机的结构或设计新的水平气流带式干燥机提供了理论依据。