新型稀土储氧材料的性能及在三效催化剂中的应用

采用共沉淀法制备了铈锆复合氧化物CeO2-ZrO2-Y2O3(CZ-Y)和CeO2-ZrO2(CZ),对其进行了BET、TPD和储氧量(OSC)的表征,并考察了这两种铈锆复合氧化物对Pt-Rh型三效催化剂性能的影响.结果表明,含CZ-Y的催化剂具有较好的低温活性和抗老化性能.     

环境和缺口形状对LY12CZ铝合金疲劳短裂纹扩展的影响

研究不同环境下LY12CZ铝合金缺口短裂纹的扩展规律及缺口形状对短裂纹扩展规律的影响.相同△K水平下,短裂纹比长裂纹有更高的da/dN值,3.5%NaCl溶液的加入,使锐、钝缺口短裂纹的da/dN值都显著增加.但无论在何种环境下,锐、钝缺口短裂纹的扩展都呈明显的"马鞍"形状且溶液中的过渡裂纹尺寸高于空气中,用缺口根部塑性区大小、裂纹闭合效应和腐蚀介质的共同作用解释试验结果.尖缺口状态下,缺口根部塑性区尺寸很小,裂纹扩展主要受裂纹闭合影响;钝缺口状态下,缺口根部塑性区作用范围较大,裂纹扩展主要受其影响.     

中间坯厚度对Q390CZ15厚板组织性能的影响

研究了不同厚度中间坯对厚50mm Q390CZ15钢板组织性能的影响。结果表明，110、100mm厚中间坯经控轧控冷后，所得产品组织性能均符合国家相关标准规定。100mm厚中间坯待温时间短，后续精轧工序少，其控轧方案更简便、合理，可有效提高生产效率。     

连接方式对紧固孔疲劳性能的影响

通过对紧固孔件的疲劳试验,研究不同连接方式对其疲劳性能的影响.对两种不同连接方式的紧固件的疲劳试验结果进行对比分析,对疲劳断口进行观察分析,基于当量初始裂纹(equivalent initial flaw size)理论计算不同连接方式下的原始疲劳质量.试验结果表明,采用沉头铆钉连接方式紧固孔的疲劳寿命略长于采用沉头螺栓连接方式的紧固孔,但沉头铆钉连接方式紧固件疲劳寿命的分散性较后者大;铆接紧固件的当量初始裂纹尺寸比螺接紧固件小,原始疲劳质量有所提高;在不同连接方式下,裂纹萌生位置不变,裂纹萌生寿命约为紧固件总疲劳寿命的80％.     

Metabolic Difference of CZ48 in Human and Mouse Liver Microsomes

CZ48, chemically camptothecin-20-O-propionate hydrate, is currently under clinical investigation. The kinetics of the metabolite camptothecin (CPT) formation and of CZ48 depletion in mouse and human liver microsomes in the presence or absence of NADPH was examined. The formation rate of camptothecin in human liver microsomes was significantly higher than that in mouse with mean K(m)s of 1.9 and 0.5 nM and V(max)s of 9.3 and 2.2 pmol/min/mg, respectively. However, the apparent intrinsic clearance (V(max)/K(m)) ratios for camptothecin in human and mouse liver microsomes were not significantly different from each other (4.9 versus 4.4) in the presence of NADPH. The depletion of CZ48 in human microsomes was four times faster with 4.55% of CZ48 remaining intact while in mouse 19.11% of the drug remained unchanged after 60 min. These results suggest that there is a remarkable species difference of CZ48 biotransformation between human and mouse. The depletion rate of CZ48 in human liver microsomes is considerably higher than that in the mouse.     

直流电脉冲修复LY12CZ铝合金疲劳损伤的研究

利用铝合金的导电性可对其损伤进行电修复,由于损伤可导致电阻变化,试样修复前后电阻值的变化可以作为判断修复程度的参考依据。将厚度为2mm的LY12CZ铝合金板材在225MPa不同循环周次下造成疲劳损伤,采用直流电脉冲修复损伤试样,并用电桥测量原始、疲劳后和修复后试样的电阻。用光学显微镜和透射电镜观察组织变化。结果表明,LY12CZ铝合金试样疲劳后,电阻值增加,经过电脉冲处理后,电阻减小,但并未恢复到原始试样的电阻值。用电阻变化可大致判断疲劳损伤的修复程度。在最大电流密度为175A/mm2下的直流电脉冲最佳的修复时间为0.8s。LY12CZ铝合金疲劳后位错密度增加,电脉冲处理后位错密度减少,并可以改变强化相与基体的界面结合程度。     

快速退火气氛对300mm CZ硅片吸杂效应和表面微观结构的影响

研究了N2和N2/NH3混合气两种不同气氛快速退火处理硅片对洁净区和氧沉淀分布的影响.研究发现:N2/NH3混合气氛处理的硅片在后序热处理中表层形成很薄的洁净区同时体内形成高密度的氧沉淀;而N2气氛处理的硅片的沽净区较厚、氧沉淀密度较低.但是两种气氛下延长恒温时间都可以降低洁净区厚度,增加氧沉淀密度.X射线光电子能谱和原子力显微镜扫描的结果显示N2/NH3混合气氛处理使表面出现了强烈的氮化反应,利用氮化反应町以解释快速退火气氛对洁净区分布的影响.     

炭/炭复合材料在半导体制造行业的应用

综述了传统炭/炭复合材料和膨胀石墨基低密度炭/炭复合材料在半导体制造业直拉(CZ)法单晶硅炉中的应用。指出了在CZ单晶炉内炭/炭复合材料比石墨材料热场零部件的优势所在,并认为随着硅单晶直径的增大,炭/炭复合材料取代石墨材料将成为硅晶体生长炉热场系统的首选材料。     

促进剂DZ/CZ并用体系硫化特性的研究

从并用比和用量两个角度考察促进剂ＤＺ／ＣＺ并用体系的硫化特性，以探讨替代促进剂ＮＯＢＳ的可能性。研究表明，促进剂ＤＺ，ＣＺ并用仅起互补作用。因为促进剂ＣＺ在交联密度和效率上均强于促进剂ＤＺ，所以并用体系的特性转变前移至１：０．５左右的并用比处。促进剂ＤＺ／ＣＺ固定并用比在硫化特性曲线上与促进剂ＮＯＢＳ只有一个相交点，只有变并用比体系才能在整个用量范围内与促进剂ＮＯＢＳ相近。提出了促进剂ＤＺ／ＣＺ变     

Silicon ingot diameter modeling in Czochralski process and its dynamic simulation

Silicon wafers are manufactured by cutting an ingot into the same thickness. The Czochralski process is a representative method for making an ingot. During manufacture, the ingot diameter is affected by the pull speed and heat transfer amount. Therefore, controlling the ingot manufacturing process involves controlling the ingot diameter related to pull speed and controlling the heater power supply to maintain the pull speed within the allowable range. The modeling of ingot diameter can be established by the ingot pull speed change based on an understanding of the mechanism of heat transfer, and the calculation of the heat transfer amount between all the parties of the crystal growth furnace according to the energy balance equations. Comparing the simulation results with real process results, the step change of the heater showed 1st or 2nd process dynamics at all points with a time delay of 18 minutes, which was similar to that of the real process. Furthermore, the pull speed step change exhibited a 5 min time delay from the test spot, which confirmed the relation between the integral and process properties. This result is similar to the real process, too. With a specific ingot length, the temperature in each point of the furnace in the real process was similar to these simulation results.