多孔粒状铵油炸药在边坡预裂爆破中的应用

通过工程实践，介绍了利用多孔粒状铵油炸药进行边坡预裂爆破的设计原理及施工工艺。该技术能确保预裂爆破质量。简化施工工序，大幅度降低爆破成本。技术经济指标优越。     

Flow stress of high density polyethylene and nylon 66 at high rates of strain

Measurement of the flow stress of high density polyethylene (HDPE) and nylon 66 at strain rates of 10³ s^?1 using a split Hopkinson pressure bar technique is discussed. The flow stress at a strain of 10% has been determined for both polymers at 20°C. The intrinsic errors involved in this technique are briefly reviewed. The results indicate that the flow stress of HDPE and nylon 66 were 50MPa and 150MPa, respectively, at strain rates of about 10³s^?1.     

Effect of alkyl chain length on the electrochemical perfluorination of n-alkane (C6–C10) carboxylic acid chlorides

Electrochemical perfluorination (ECPF) of n-hexanoyl, n-heptanoyl, n-octanoyl, n-nonanoyl and n-decanoyl chlorides was carried out under identical experimental conditions in liquid HF. The product distribution among perfluorinated carboxylic acids, perfluoro ethers, perfluoroalkanes, isomerised and fragmented products containing less number of carbon atoms was identified using ¹⁹F NMR. The selectivity of C₆–C₁₀ perfluoro carboxylic acid varied between 29 and 36%. The alkali insoluble perfluoro cyclic ether and perfluoro alkane fractions increased with increasing chain length. The increase of perfluoroalkane fractions is mainly due to decarboxylation. Cyclic ether fractions also decreased slightly with increase in chain length. Among the cyclic ethers α substituted oxolanes were the predominant products. Six membered cyclic ethers were always found to contain β substitution. The possible pathways for these products are also indicated. An erratum to this article can be found at     

Electrolytic regeneration of bleach solution in the motion picture industry

Cyclic voltammetric and galvanostatic experiments have been carried out with both synthetic and commercial bleach solutions with a view to regenerating the same. Maximum efficiency could be achieved if the oxidation is carried out below an anodic potential of 0·80 V vs SCE. The data obtained in galvanostatic experiments with RCE confirm the results of the earlier technique.     

AN EXPERIMENTAL-NUMERICAL METHOD FOR MEASURING CRACK PROPAGATING VELOCITIES UNDER STRESS WAVE LOADING

An experimental-numerical method for measuring dynamic crack propagating velocities under stress wave loading is established in this paper. The experiments of the three-point bend specimen are done on the improved Hopkinson bar. Deflection of loading point, dynamic load and instantaneous crack length are measured, then crack propagating velocities are calculated. Experiments on 40Cr steel show that the results given by this method have a good agreement with that obtained by the resistance fracture gage method. Therefore this method is feasible for measuring crack propagating velocities under high loading rate and will have wide application.     

Fractionation of partially stereoregular poly(propylene oxide)

Partially stereoregular poly(propylene oxide) samples were synthesized via reactions catalysed by a preformed analytically defined trimethylaluminium hydrolysate. These samples were fractionated into two contrastingly different fractions.

1. (i) D-polymers: This fraction constituted the major part (up to 90%). It mainly contained cyclic low molecular weight oligomers (MW < 1000). The linear chains found in D-polymers had hydroxyl end groups. No double bonds could be detected spectroscopically.

2. (ii) K-polymers: This fraction was high molecular weight stereoregular polymer. Stepwise thermal precipitation from dilute isooctane solution of K-polymers yielded a succession of fractions which differed in melting point. It appears that the phase equilibria during the thermal precipitations were not controlled by the molecular weights of species.

化学清洗中不容忽视的步骤——钝化

对低压锅炉化学清洗中容易被忽视的“钝化”这一步骤，从理论上进行了探讨，并介绍了相应的钝化工艺及防腐措施     

高柔韧性聚氨酯丙烯酸酯的合成及应用

选用不同结构的多元醇作骨架，合成一系列高性能的聚氨酯丙烯酸树脂，并通过对聚氨酯丙烯酸树脂性能的对比研究，发现以聚丁二烯二元醇为骨架的聚氨酯丙烯酸酯树脂具有极佳的柔韧性和优异的低温耐曲折性。     

T.C.Powcrs模型若干问题的研究

从T.C.Powers水泥石模型出发,提出了描述水泥混凝土材料初始结构的主要参数是初始孔隙率。由此池绎了水泥浆体组成与结构的定量关系,比原模型有更明了的物理意义,研究结果表明,Powers模型在高孔隙率范围内具有适用性,但不适用于低孔隙率硬化水泥浆体,且在低孔隙率条件下不存在28％的固有凝胶孔隙率,水化产物成份和性质是渐变的。     

A203型低温氨合成催化剂使用小结

对Ａ２０３型低温氨合成催化剂的使用进行总结，介绍了该催化剂的装填，升温还原情况及使用效果。