MIS／IL硅太阳电池耐紫外辐射性能的研究

通过比较蒸发铯和浸渍铯在ＭＩＳ／ＩＬ硅太阳电池中所引入的铯量、固定正电荷量、界面态密度和对太阳电池表面面电阻的影响，以及测量上述诸量和太阳电池的主要参数经紫外辐照后的变化，并从表面能带的角度分析了引入铯对太阳电池的紫外辐射稳定性的影响，解释了在ＭＩＳ／ＩＬ硅太阳电池中引入铯使该器件耐紫外辐射性能提高的原因。     

改性超稳Y沸石负载的杂多酸铯盐在草莓酯合成反应中的催化性能

制备了一系列以脱铝超稳Y沸石(DUSY)为载体的磷钨酸(PW)及其铯盐催化剂,考察了催化剂在以乙酰乙酸乙酯和1,2-丙二醇为原料催化合成草莓酯反应过程中的性能。结果表明,在负载量(质量分数)为30%的Cs2.5H0.5PW/DUSY催化剂上的乙酰乙酸乙酯的转化率最高,达到95.3%,草莓酯的选择性为100%。得到了适宜的反应条件:反应温度363K,n(乙酰乙酸乙酯)∶n(1,2-丙二醇)=1∶1.5,催化剂占反应体系的质量分数为0.8%,带水剂环己烷占反应体系的质量分数为36%。经过5次反复使用后,负载型磷钨酸铯盐催化剂的催化活性仍较高,转化率达88.2%,而相应的负载型磷钨酸催化剂的催化活性却大幅度下降,转化率仅有31.2%。催化剂活性下降的主要原因是在极性反应体系中杂多酸化合物活性组分流失,而负载型磷钨酸铯盐良好的稳定性源于其难溶脱性。     

Systematic hardness measurements on CsClxBr(1?x) and NH4ClxBr(1?x) mixed crystals

Vickers hardness measurements have been made on polycrystalline blanks of CsCl _x Br_(1−x) and single crystals of NH₄Cl _x Br_(1−x). The composition dependence of hardness is highly nonlinear in both systems and follows an empirical model that includes a lattice contribution and a disorder contribution. The Gilman-Chin parameter (H/C ₄₄) has been calculated and its significance discussed.     

杯冠化合物在处理高放废液中的应用（I）——新型萃取剂异丙氧基杯[4]冠-6的合成与表征

研究以对叔丁基苯酚和甲醛等作为初始原料合成中间体对叔丁基杯[4]芳烃、杯[4]芳烃和异丙氧基杯[4]芳烃；以二缩三乙二醇和氯化亚砜等作为初始原料合成中间体二氯代三甘醇、五甘醇和五甘醇对甲苯磺酸酯。最后，由异丙氧基杯[4]芳烃和五甘醇对甲苯磺酸酯合成了目标产物二(2-丙氧基)杯[4]冠-6，对合成的各种中间体和目标产物进行了表征。     

固体酸催化正己醇酯化反应的研究

分别以固体酸CsnH3 -nPW12 O40 和SO2 -4/ZrO2 为催化剂研究了正己醇酯化反应。考察了磷钨酸铯盐中铯含量和酸强度、SO2 -4/ZrO2 中酸浓度和酸强度以及不同有机酸对正己醇酯化反应的影响。结果表明 ,正己醇的酯化反应活性随着固体酸的酸强度和比表面积的增加而增加。利用IR、XRD、空气吸附法等检测手段分别对催化剂进行了表征。     

History of Lake Ontario Contamination from the Niagara River by Sediment Radiodating and Chlorinated Hydrocarbon Analysis

Contamination of Lake Ontario by persistent organic compounds began with the development of the chemical industry along the Niagara River. These compounds are discharged to the river where they are scavenged from the water column by sedimenting particulates which in turn settle out in depositional areas of Lake Ontario. We have determined ²¹⁰Pb, ¹³⁷Cs, and chlorinated hydrocarbon profiles of sediment cores taken about 3 km from the mouth of the Niagara River. Age profiles of the sediments were constructed from the radionuclide measurements and used to determine historic trends of chlorinated hydrocarbon input to Lake Ontario. The historical record found in the sediments for chlorobenzenes, chlorotoluenes, hexachlorobutadiene, octachlorostyrene, mirex, and PCBs is in good agreement with known production and usage patterns of the chemicals. Pollution of Lake Ontario with chlorinated hydrocarbons from the Niagara River is still occurring, but the worst contamination of the lake occurred in the 1960s.     

Ellipsometry of Liquid Helium Films on Gold, Cesium, and Graphite

We have developed a modulated null ellipsometer with sub-monolayer resolution to measure adsorbed liquid helium thin films at temperatures below 4 K. Adsorption isotherms of ⁴He on gold, cesium, and graphite are presented. For Au and Cs substrates, the reflecting surface for our ellipsometric measurements is the metallic electrode of a quartz crystal microbalance(QCM). Performing both types of measurements simultaneously on the same substrate provides a direct method of converting the ellipsometric signal into an absolute film thickness without constructing a detailed model of the refractive index of the substrate. Isotherms on gold above and below T¸ show that the ellipsometric signal is unaffected by the superfluid transition; the ellipsometer measures the total film thickness independent of the superfluid fraction. Isotherms on cesium above the wetting temperature show a prewetting step. Isotherms on clean graphite show steps due to layering.     

Research in creating a fountain type frequency standard

Results of research aimed at creating a new generation of quantum frequency standards, i.e., a cesium fountain, are presented. Measurement data for controlling and detecting cold atoms are analyzed. The possibility of cooling cesium atoms to a level of the order of 2 µK is demonstrated by experiment.Translated from Izmeritelnaya Tekhnika, No. 1, pp. 18–23, January, 2005.     

磷钨酸铯催化合成对甲氧基苯乙酮

以磷钨酸铯(Cs2.5H0.5PW12O40)为催化剂合成了对甲氧基苯乙酮(p-MOAP),采用傅里叶变换红外光谱、X射线衍射、N2吸附和NH3程序升温脱附等方法对Cs2.5H0.5PW12O40催化剂进行了表征;考察了Cs2.5H0.5PW12O40催化剂活化温度、反应条件及反应产物等对苯甲醚乙酰化反应的影响。表征结果显示,多孔性的Cs2.5H0.5PW12O40催化剂保持了H3PW12O40的Keggin结构和酸强度,但酸量明显小于H3PW12O40。实验结果表明,适宜的p-MOAP合成条件为:300℃下活化的Cs2.5H0.5PW12O40催化剂用量为0.18g(以20mmol乙酸酐计)、n(苯甲醚):n(乙酸酐)=10、反应温度115℃、反应时间40min。在此条件下进行了4次重复实验,p-MOAP的收率达61.3%～64.8%、选择性达96.10%～96.80%。苯甲醚乙酰化反应的产物p-MOAP和醋酸对Cs2.5H0.5PW12O40催化剂的活性具有抑制作用。     

基于Vondark-Cepek滤波的氢铯时间尺度融合方法研究

氢原子钟和铯原子钟是当前国际原子时和各国标准时间产生的主要精密频率源,二者分别拥有优良的短期和长期稳定度特性。充分利用氢钟短稳和铯钟长稳进行时间保持成为时间产生过程中的一项关键技术。以提高时间尺度的长短期稳定性为目标,提出了Vondark-Cepek组合滤波的氢铯融合时间产生方法。首先利用AT1算法分别对氢钟组和铯钟组各产生一个钟组时间尺度,然后根据最小二乘原则对Vondark-Cepek组合滤波关键参数进行选取,进而通过氢钟组时间尺度时间序列的差分信息对铯钟组时间尺度进行性能增强,从而获得氢铯融合时间尺度。计算结果表明:该时间尺度1 h稳定度为3. 36×10-15,15 d稳定度为3×10-15,均优于氢铯单个时间尺度相同平均时间上的性能指标。