Yun-Jong Kim
,
Sang-Bae Kim
,
Hyun-Hye Park
,
Myeong-Deok Seo
,
Byoung-Cheon Lee
,
Man-So Han
,
Taik-Nam Kim
,
Sung-Baek Cho
材料科学技术（英文）
Generally the gold investment material consists of cristobalite, quartz and plaster. The physical property of gold investment materials depends on its thermal expansion coefficients, compressive strength, and particles size distribution. Since the thermal expansion coefficient of cristobalite and quartz are 2.6×10-6/℃ and 2.32×10-6/℃ respectively, the composition ratio of each components influence the thermal and physical properties of gold investment materials. For the clinical applications, it is necessary to improve the properties of gold investment materials such as homogeneous size distribution and thermal expansion coefficients. In the present study, effect of inorganic fillers such as cristobalite and quartz on gold alloy investment was investigated to improve the properties of it. The compressive strength and thermal expansion coefficients of the specimens were evaluated. The results showed that cristobalite and quartz were homogeneously distributed by milling. The optimum compressive strength was obtained at the ratio of 42:22 cristobalite and quartz, respectively.
关键词:
Investment
,
null
,
null
,
null
,
null
熊凯
,
朱勇平
,
王炼石
,
蔡彤旻
,
张安强
,
曾祥斌
高分子材料科学与工程
用悬浮接枝共聚法合成了乙烯-1-丁烯共聚物(PEB)与甲基丙烯酸甲酯(MMA)-丙烯腈(AN)的接枝共聚物(PEB-g-MAN).用不同性质的溶剂以抽提法将接枝共聚产物所含组分逐步分离,用傅立叶变换红外光谱(FT-IR)分析了各组分聚合物的归属.研究了AN/(MMA+AN)投料质量比(fAN)对接枝共聚反应行为及产物各组分含量的影响.用凝胶渗透色谱法(GPC)对各组分相对分子质量及其分布进行了表征.结果发现,接枝共聚体系存在PEB与MMA-AN接枝共
聚、PEB与MMA接枝均聚、MMA与AN共聚和MMA均聚等基元反应.
关键词:
乙烯-1-丁烯共聚物与甲基丙烯酸甲酯-丙烯腈接枝共聚反应
,
橡胶接枝率
,
组分分离
,
傅立叶变换红外光谱
,
基元反应
,
凝胶渗透色谱法
郑桂丽
,
姜丽
,
张志东
液晶与显示
doi:10.3969/j.issn.1007-2780.2010.06.001
根据Erickson-Leslie流体动力学理论,研究了混合排列向列相-共面转换液晶盒的引流效应.在强锚定边界条件下,经过理论推导,得出液晶指向矢与流速的关系方程,进一步通过数值计算得出指向矢分布与时间的关系.发现引流效应加快了指向矢达到平衡态的速度,而且破坏了指向矢分布的瞬态对称性,特别在加电压的初始几毫秒这种现象非常明显.
关键词:
混合排列向列相
,
共面转换
,
引流效应
,
指向矢分布
Transactions of Nonferrous Metals Society of China
Initial atmospheric corrosion of zinc in the presence of Na2SO4 and (NH4)(2)SO4 was investigated via quartz crystal microbalance(QCM) in laboratory at relative humidity(RH) of 80% and 25 degrees C. The results show that both Na2SO4 and (NH4)(2)SO4 can accelerate the initial atmospheric corrosion of zinc. The combined effect of Na2SO4 and (NH4)2SO4 on the corrosion of zinc is greater than that caused by (NH4)(2)SO4 and less than that caused by Na2SO4. Fourier transform infrared spectroscopy(FTIR), X-ray diffractometry(XRD) and scanning electron microscopy(SEM) were used to characterize the corrosion products of zinc. (NH4)(2)Zn(SO4)(2), Zn4SO4(OH)(6)center dot 5H(2)O and ZnO present on zinc surface in the presence of (NH4)(2)SO4 while Zn4SO4(OH)(6)center dot 5H(2)O and ZnO are the dominant corrosion products on Na2SO4-treated zinc surface. Probable mechanisms are presented to explain the experimental results.
关键词:
zinc;Na2SO4;(NH4)(2)SO4;atmospheric corrosion;sulfur-dioxide;nacl;so2;deposition
党玉华
钢铁
烧结过程中SO2的产生受加热温度、加热时间、氧气浓度、焦粉粒度、混合料水分、碱度等因素影响。通过对铁矿烧结过程SO2排放规律的系统研究，设计了烧结烟气脱硫综合方案，脱硫装置处理烟气中SO2 浓度提高50%左右， SO2脱除率达到98%。
关键词:
烧结;烟气脱硫;SO2脱除率
党玉华
,
王海风
,
齐渊洪
钢铁
研究了铁矿烧结过程中SO2的排放规律.研究结果表明:烧结过程中SO2的浓度受加热温度、加热时间、氧气浓度、焦粉粒度、混合料水分、碱度等因素影响.设计了烧结烟气脱硫综合方案,脱硫装置处理烟气中SO2浓度提高50%左右,SO2脱除率达到98%.
关键词:
烧结
,
烟气脱硫
,
SO2脱除率
张允书
,
李选明
,
石声泰
中国腐蚀与防护学报
研究了涂有 K_2SO_4～Na_2SO_4 盐膜的工业纯铁在 O_2～0.1、0.5和1.0%(SO_2+SO_3)气氛中于560～750℃温度范围内的低温热腐蚀行为。结果表明,工业纯铁的低温热腐蚀是由低熔点的 K-Na-Fe 三元复合硫酸盐引起的,并依铁的溶解-铁的氧化物的沉积机制发展。
关键词:
邵忠宝
,
赵敬棋
腐蚀学报（英文）
研究了Na2SO3的除氧效果，讨论了pH值、Ca和Mg 离 子浓度、催化剂Co(NO3)2的浓度对Na2SO3除氧效果的影响.实验结果表明：在无催 化剂存在的情况下，Na2SO3的除氧率最高仅达到90%.Ca、Mg离子浓度对Na2SO3的 除氧效果有一定的抑制作用，使除氧率降低约4%～6%.催化剂Co(NO3)2的引入，能够明 显地提高Na2SO3的除氧率，降低Na2SO3的用量，当Na2SO3加入量过剩约5.0 mg /L，催化剂Co(NO3)2的加入量为1.5 mg/L时，除氧率大于99.5%，且Ca、Mg离子浓度及p H值对其除氧率影响很小.
关键词:
Na2SO3
,
catalyst
,
Co(NO3)2
,
rate of deoxidation
