Improved Prediction of Ozone Levels in Urban and Rural Atmospheres

Based on data obtained in terms of the first International cooperative program on the effects of acidic precipitations on materials (ICP Materials) of the United Nations European Commission on Economics (UN ECE), the relations between the ozone O₃ and nitrogen dioxide NO₂ concentrations in combination with the sunshine effect (taken into account either as the solar radiation (Rad) or the sunshine duration (Sun)) are considered. Analysis based on monthly and annual averages led to a new equation recommended for predicting ozone levels over rural, urban, and industrial areas of Europe as a function of NO₂ concentration and Sun parameter. Using Rad instead of Sun provides similar results, but, for practical usage, the equation involving a more easily available parameter Sun was recommended. The new equation corrects and improves the earlier proposed one, in which the concentration of ozone was given as a function of NO₂ concentration solely, and is included in the UN ECE Manual on mapping critical loads / levels and geographical areas where they are exceeded.     

Thermomechanical stress fields in high-temperature fibrous composites. I: Unidirectional laminates

This two-part paper presents a closed-form procedure for evaluation of estimates of local thermomechanical stress fields in two-phase fibrous composites and laminates. The first part is concerned with a unidirectional elastic laminate subjected to uniform mechanical loads and to uniform changes in temperature. Both phases are assumed to be elastic, with temperature-dependent moduli and expansion coefficients; the solution reflects the influence of thermomechanical interactions. Exact solutions are not possible for any real system, because the local geometry is not known in detail. Instead, estimates of the fields are found from a modified Mori-Tanaka approximation. Examples are presented for two SiC/Ti---Al---Nb composites. Local stresses of interest are found after cooling from fabrication to room temperature. The presence of local yielding, and the influence of coupling terms on the local stress magnitudes are examined. Extension of the results to laminated plates is presented in Part II (Dvorak, G.J., Chen, T. & Teply, J., Composites Science and Technology, 43 (1992) 359–368, this issue).     

Comparative study of crystallization processes in Sb2Te3 films using laser and thermal annealing techniques

Adherent and pin-hole free amorphous Sb₂Te₃ thin films have been obtained by vacuum evaporation at substrate temperatures ≤25 °C. The films have been crystallized by thermal and laser annealing, and the crystallization processes monitored as a function of annealing temperature and laser scan speed. A comparative study of topography reveals disk-shaped crystallized areas in thermal crystallization and dendrite growth in the laser induced process. The crystallized films in both cases contain a single Sb₂Te₃ phase. Activation energy of 2 eV for crystallization, determined using differential scanning calorimetery indicates good room temperature stability of the amorphous states.     

TURBULENCE MEASUREMENT INSTRUMENT WITH A SILICON PIEZORE-SISTANCE BEAM

A newly developed turbulence measurement instrument is introduced in the paper.The transducer of the device is based on the principle of the effect of silicon piezoresistance that isintegrated in a Wheatstone bridge on a pure silicon beam. At one end of the beam, a small lightball is installed as the target forced by the water flow. The other parts are prevented from thewater flow with a sophisticated stainless steel tube. The instrument can be used to measure turbu-lent velocities either in clear Water or in flows bearing hyperconcentration of sediment. It can al-so be used to measure velocities in both glass flume and model experiments as well as in pipe ex-periment by being mounted in a special way.     

丙烯酸酯聚氨酯紫外固化凝胶生成动力学研究

采用丙烯酸酯聚氨酯和二苯甲酮/安息香乙醚复合光敏剂,对该体系紫外光固化反应的凝胶生成动力学进行分析。用红外光谱定量测定光聚合过程的变化,发现光聚合反应主要是以双键打开,交联为特征的,并得出1408cm~(-1)双键吸收峰随光照时间而变化的关系式:P_(c=c)=0.325 t~(0.135)。临界凝胶点可由双键反应程度与凝胶分数之间关系外推得到,凝胶点后,体系中存在一个凝胶与溶胶之间分配关系,此时凝胶与溶胶共存,凝胶中双键反应程度P_(A(g))>总双键反应程度P_A>溶胶中双键反应程度P_(A(S))。随着凝胶增加,P_A和P_(A(g))逐渐上升,而P_(A(s))下降。此体系的紫外固化实验工作曲线与理论值基本一致。     

含氚废水水泥固化实验研究

研究用水泥固化处理氚废水,并选择了最佳配方:水与灰的重量比=0.45～0.5,水泥与石膏重量比=5∶1。用IAEA推荐的方法做浸出实验。为了减少水泥固化体中氚的浸出量,实验了几种涂层材料。沥青涂层可将固化体氚的浸出率降低1～2个量级。     

原子高离化态研究装置

介绍了原子高离化态研究装置,包括重离子加速器、测量装置、数据获取和处理系统。     

仲胺衍生物柴油流动改进剂

考察了十八种胺衍生物改善高含蜡柴油低温流动性的作用规律。结果表明，仲胺衍生物主要是通过增溶柴油中的长链正构烷烃，使浊点、冷滤点降低，从而改善柴油低温性能。仲胺衍生物与T1804流动改进剂（乙烯-醋酸乙烯酯聚合物）复合可以改善蜡晶的分散性能，对降低柴油冷滤点有增效作用。     

碾压混凝土坝施工进度与质量控制的新措施

碾压混凝土重力坝和拱坝由于连续施工的坝体混凝土体积大，施工期间需要采取较为严格的温度控制措施，而所采取的温控措施是否有效，目前尚没有一个能够用于实际施工过程的快速有效的评估方法和方式，不能根据已施工坝体内的实际情况来控制施工进度和质量。利用分布式光纤温度测量系统来快速地获得坝体混凝土内部的大量温度信息，进而实际标定温度仿真程序并通过标定过程模拟拟施工的连续碾压层，以检验其温控措施的有效性。通过坝体内部的温度、温度变化速率和梯度来达到实时控制坝体碾压上升速度、坝面和仓面养护、以及冷缝灌浆处理等目的。     

包钢氟污染治理成效及对策

本文介绍了包钢历年来氟污染治理成效以及控制外排氟总量达标的具体措施.