顺(反)-4,4''''-双(4-羟基苯基偶氮)二苯并冠醚的合成与表征

以顺(反)-二氨基二苯并-14-冠-4、顺(反)-二氨基二苯并-18-冠-6和苯酚为原料,通过重氮化和偶联反应合成了4个新的顺(反)-4,4′-双(4-羟基苯基偶氮)二苯并-14-冠-4(化合物1和2)和顺(反)-4,4'-双(4-羟基苯基偶氮)二苯并-18-冠-6(化合物3和4).化合物的结构通过元素分析、紫外光谱、红外光谱和核磁共振波谱等手段确证.发现反式-构型的化合物2和4的熔点高于顺式-构型的化合物1和3的熔点.     

Phylogenetic position of Ephedra rhytidosperma, a species endemic to China： Evidence from chloroplast and ribosomal DNA sequences

The chloroplast genes matK and rbcL, ribosomal gene 18S and ITS regions of nuclear ribosomal DNA from Ephedra rhytidosperma, a species endemic to China, were sequenced and its phylogenetic position was investigated. Independent and combined phylogenetic analyses for the DNA sequences from 16 taxa representing 15 species of the genus Ephedra were performed using the maximum parsimony （MP）, neighbor-joining （N J）, minimum evolution （ME） and maximum likelihood （ML） methods. The results indicate that E. rhytidosperma is closely related to E. equisetina. The divergence time between them is estimated to be 10.85±2.44 Ma based on the results of the relative-rate tests and the evolutionary rate of rbcL gene.     

电机护环钢在硝酸盐溶液中应力腐蚀开裂的控制过程研究

本文在文献［１］基础上，运用金相，电化学方法研究了５０Ｍｎ１８Ｃｒ４电机护环钢依照ＱＨＪ－７９试验标准在硝酸盐介质中应力腐蚀开裂（即ＳＣＣ）的性质，结果指出，此体系中ＳＣＣ的控制过程为阳极溶解。     

基于KYN18-12高压开关柜事故原因及相应措施

随着配电网自动化的迅速发展和供电可靠性的日益提高，对开关柜的要求也愈来愈高了，特别是变电所在逐步实现综合自动化进而为无人值守时，对开关及开关柜运行状态的无事故提出了更多的要求。文章阐述了高压开关柜的概念、并结合KYN18-12开关柜具体论述了常见的事故及原因，并针对事故做出了具体的技术改善对策。     

Dawson结构磷钨酸钕制备、表征及催化合成四氢呋喃

通过复分解法制备Dawson结构Nd₂P₂W₁₈O₆₂催化剂,并通过XRD、EDS、SEM和FT-IR等方法表征催化剂.以催化1,4-丁二醇液相脱水环化合成四氢呋喃为探针反应,通过正交实验确定了反应的最佳条件:w(催化剂)=2.6%(相对于1,4-丁二醇质量),反应温度为190 ℃,反应时间为40 min,四氢呋喃的平均产率为97.6%,催化剂重复使用到第3次时,四氢呋喃收率为87.9%.本工艺具有绿色、安全、操作简单、收率高等优点.     

Study of altitudinal lapse rates of δ18O in precipitation/river water with seasons on the southeast Tibetan Plateau

Seasonal δ^18O variation in water on the southeast Tibetan Plateau has been studied, showing the consistent variation pattern of δ^18O with altitude indicative of relevant atmospheric circulation processes. Study shows a similar variation pattern of fixed-site river water δ^18O with that of the precipitation δ^18O in southeast Tibet. δ^18O in regional rivers in southeast Tibet demonstrates a gradual depletion with increasing altitude, though the rates vary seasonally. The most depleted river ^18O occurs during the monsoon period, with the lowest δ^18O/altitude lapse rate. The river ^18O during the westerly period is also depleted, together with low δ^18O/altitude lapse rate. The pre-monsoon rivers witness the most enriched ^18O with least significant correlation coefficient with the linear regression, whilst the postmonsoon rivers witness the largest δ^18O/altitude lapse rate. Different coherence of seasonal δ^18O variation with the altitude effect is attributed to different moisture supplies. Though sampling numbers vary with seasons, the δ^18O-H linear correlation coefficients all reach the 0.05 confidence level, thus witnessing the variation features of δ^18O in seasonal river water due to the influence of atmospheric general circulation and land surface processes revealed from the altitudinal lapse rates.     

无铅压电陶瓷（Sr2-xCax）2Bi4Ti5O18制备及其压电性能研究

采用固相合成法制备了铋层状无铅压电陶瓷Sr2-xCaxBi4Ti5O18(SCBT)(O≤x≤0.2).利用XRD对900℃合成出的粉体进行了表征,结果显示粉体相结构是Aurivillius结构相.通过SEM形貌分析可以看出1 160℃保温2 h烧结出的陶瓷为片状结构.研究结果表明SCBT陶瓷的居里温度、矫顽场随钙含量的增加而增加.     

天山乌鲁木齐河源1号冰川雪冰中δ18O的演化过程

2002年9月14日-2005年3月7日,在天山乌鲁小齐河源1号冰川积累区雪坑中连续观测取样,频率为1次/周,分析了其巾的部分表层雪样品和粒雪坑样品中的δ18O.结果表明:表层雪样品的δ18O具有明显的季节变化,且与月平均温度关系密切.粒雪坑样品中的δ18O在9月底至次年6月初变化较小,升华对雪坑1 m以下雪冰中δ18O的影响不超过-2‰,整个雪坑都较好地保持了δ18O的季节变化特征.但6月初-9月底融水对雪冰中δ18O的影响巨大,冬季形成的δ18O低于-30%的中、细粒雪层,经过夏季融水的改造,可成为δ18O-11.6‰的粗粒雪和冰片层.融水可使雩冰中δ18O的改变最>60%.在全球变暖背景下,冬季形成的低δ18O雪层经过夏季融水的改造,其内的δ18O可以完全被平滑.     

1Cr18Ni9Ti激光表面熔覆合金结构相的研究

１Ｃｒ１８Ｎｉ９Ｔｉ不锈钢的表面Ｃｏ基材料的激光熔覆，在熔覆层表面形成了致密的微结构，基体与熔覆层间的热影区内，基体元素的固溶度明显增加，位错能降低，在热影响区还发现了孪晶产生，根据Ｍ谱研究确诊有多种Ｆｅ、Ｃ固溶相的存在。