Conversion of an Investment Casting Sprue Wax to a Pattern Wax by Chemical Agents

In this research, the properties of a commercial investment casting sprue wax (B97) were modified to improve its properties so it can be used as a pattern wax in investment casting. For this purpose, some colloids (gum arabic, pectin, agar, polyvinylpyrrolidone-40, polyvinylpolypyrrolidone, alginic acid, cellulose, carboxymethyl cellulose, silicon, tannic acid, saponin), some surface active agents (sodium dodecyl sulfate, sorbitane oleostearate, glycerine), and activated charcoal and palmitic acid were used as additives or fillers. The effect of these chemicals on the surface roughness, solidification shrinkage, apparent viscosity, hardness, tensile strength, and wettability of B97 wax were investigated. These additives modified the properties of B97 sprue wax to such an extent that it had properties superior to those of a commercial investment casting pattern wax (B140).     

氮化硅的α→β相变的影响因素

本文研究了氮化硅α→β相变的诸影响因素。发现 Y_2O_3添加剂具有最显著的相变促进作用,而 La_2O_3添加剂促进相变的作用最小,但后者对促进 Si_(?)N_4致密化的作用较前者显著。原始氮化硅粉末的比表面、杂质含量及颗粒形貌均会影响α→β相变的程度。     

我国钻井液转化成水泥浆技术现状

本文综述了国内钻井液转化成水泥浆技术（ＭＴＣ技术）研究和应用简况并作了分析讨论。     

Effects of [HMIM]HSO<Subscript>4</Subscript> and [OMIM]HSO<Subscript>4</Subscript> on the electrodeposition of zinc from sulfate electrolytes

The effects of the organic additives 1-hexyl-3-methylimidazolium hydrogen sulfate ([HMIM]HSO₄) and 1-octyl-3-methylimidazolium hydrogen sulfate ([OMIM]HSO₄) on current efficiency (CE), power consumption (PC), polarization behavior of the cathode, deposit morphology, and crystallographic orientation during electrodeposition of zinc from acidic sulfate solution were investigated. The results were compared with those of a common industrial additive, gum arabic. Addition of these additives increases current efficiency, decreases power consumption, and improves the surface morphology at lower concentrations. Both the additives showed similar polarization behavior to gum arabic and the extent of polarization was in the order: gum arabic > [OMIM]HSO₄ > [HMIM]HSO₄. The nature of the electrode reactions was studied through measurements of Tafel slopes, transfer coefficients, and exchange current densities. Data obtained from X-ray diffractogram revealed that the presence of any of these additives did not change the structure of the electrodeposited zinc but affected the crystallographic orientation of the crystal planes.     

Effects of promoter and moisture on the deactivation of FSO<Subscript>3</Subscript>H catalyst in the synthesis of HFC-152a by hydrofluorination of acetylene

The effects of promoter type and moisture on the catalytic activity of fluorosulfonic acid (FSO₃H) as a liquid catalyst for the synthesis of HFC-152a by the hydrofluorination of acetylene were investigated. The catalyst containing SnCl₄ as a promoter had a long catalyst lifetime compared to that without any promoter. It was also found that the composition of HFC-152a can be maintained at 100% for a long time by the control of the moisture content.     

清洁催化氧化苯甲醛制备苯甲酸

以过氧化氢作为氧化剂,Na2WO4·2H2O作为催化剂来催化氧化苯甲醛制备苯甲酸。选用与催化剂等物质的量的NaHSO4·H2O作添加物,分别考察反应时间,催化剂的物质的量对苯甲酸收率的影响。反应产物通过测熔点、红外光谱来分析。得出反应的最佳实验条件为:回流温度下,n(苯甲醛)／n(Na2WO4·2H2O)／n(添加物)／n(过氧化氢)为100:1:1:250,反应时间为5 h。改变添加物的种类,进一步对23种添加物对苯甲酸收率的影响进行了考察。结果表明,在最佳实验条件下,选择对甲苯磺酸为添加物时,苯甲酸收率达84.05％。     

High thermal conductive Cu-diamond composites synthesized by electrodeposition and the critical effects of additives on void-free composites

This study presents high thermal conductivity (TC) Cu-diamond composites synthesized by electrodeposition and the critical effects of two kinds of competitive additives (DVF-B, accelerator, DVF-C, inhibitor) on electroplating void-free Cu matrix diamond composites. The surface and internal microstructures of the composites synthesized with different plating time are investigated, which show the critical effects of additives. Well-combined diamond/copper interfaces are promoted and void-free Cu-diamond composites are obtained, leading to the improved TC of 614.87 W/m K. The effects of DVF-B and DVF-C on microstructure, crystallization, interfacial combination of the composite materials are detailed investigated. Interestingly, DVF-B tends to promote copper fully filling in small and micro intervals formed by diamond particles, while DVF-C prefers to restrain copper deposition in large intervals and leveling copper nodules. Thus, voids/gaps and nodules are eliminated in Cu-diamond composites, leading to the well-combined interface and high TC. The concentrations of additive system are recommended as DVF-B of larger than 5 ml/L with DVF-C from 5 ml/L to 14 ml/L. This work utilizes the competitive additives for electroplating void-free copper matrix - diamond composites, which may solve the limitation of high TC Cu-diamond composites in microelectronic industry.     

Attitudes toward chemicals are associated with preference for natural food

Consumers express concerns about chemicals in their diet. We hypothesized that general positive and negative attitudes toward synthetic chemicals and dose-response insensitivity influence consumers’ risk perceptions of chemicals in food and preference for natural food. We expected gender differences in these domains. Data was taken from a postal survey. Structural equation modeling was used to test our hypotheses. Positive attitudes toward chemicals were correlated negatively, and dose-response insensitivity was correlated positively, with risk perceptions of chemicals in food. Risk perceptions of chemicals in food were positively correlated with preference for natural food. For all variables, gender differences were observed. Our findings show that general attitudes toward chemicals influence perceptions in the food context. Consumers’ dose-response insensitivity might lead to an inappropriate perception of exposure hazards. Contaminants and additives in food are perceived differently according to their origin. Women are more sensitive than men to chemical exposure hazards.     

Friction and wear characteristics of ZDDP in the sliding of steel against aluminum alloy

The tribological properties of zinc dialkyldithiophosphate (ZDDP) antiwear additives in the sliding of steel against aluminum alloy were investigated by an oscillating friction and wear apparatus, an Optimol SRV tester. It was found that ZDDP produced larger wear of aluminum alloy than base stock, especially at high concentration. The acting mechanism of ZDDP in the lubricated aluminum-on-steel system was proposed.     

新型高效磷系极压剂的研究

根据分子设计原理,合成了一种磷系极压抗磨剂,试验结果表明,含磷添加剂具有优异的摩擦磨损性能,其PB、PD值有较大提高,已超过硫化异丁烯的极压抗磨性能.