反相高效液相色谱法测定血清中的游离氨基酸

肝脏是氨基酸(支链氨基酸除外)新陈代谢的重要器官,而且对维持氨基酸代谢的平衡起重要的作用。当肝细胞严重损害时就会引起氨基酸代谢障碍和紊乱,使氨基酸之间比例失调,尤其明显地是支链氨基酸与芳香族氨基酸比值发生改变。根据该比值的改变情况既可预测肝性脑病,又可判断肝脏疾病的严重程度,而且氨基酸的测定对许多疾病的诊断及治疗均具有重要的价值,     

Micromagnetic simulation for high field sensors with perpendicular magnetizations

In this paper, we present a micromagnetic design for high field sensors. The hard layer of the sensors is L1垂直磁化;强磁场传感器;微磁学模拟;高巨磁阻效应micromagnetic simulation, giant magnetoresistive, coercivity, demagnetizing fieldProject supported by the Nature Science Foundation of China (Grant No~10404019) and by the Science and Technology Committee of Shanghai (Grant No~05PJ14090).2006-09-232006-11-28In this paper, we present a micromagnetic design for high field sensors. The hard layer of the sensors is L1垂直磁化;强磁场传感器;微磁学模拟;高巨磁阻效应micromagnetic simulation, giant magnetoresistive, coercivity, demagnetizing fieldProject supported by the Nature Science Foundation of China (Grant No~10404019) and by the Science and Technology Committee of Shanghai (Grant No~05PJ14090).2006-09-232006-11-28In this paper, we present a micromagnetic design for high field sensors. The hard layer of the sensors is L10-FePt which is magnetized perpendicularly to film plane and the sense layer is NiFe which is magnetized in the film plane. The magnetization configurations of the hard and sense layers at different external magnetic fields have been simulated. In micromagnetic simulation, the sense field up to one tesla can be reached by using this sensor. We find that whether the sensor has a symmetric or an asymmetric field-sensing window is determined by the coercive field of the hard layer and the demagnetizing field of the sense layer.Corresponding author. E-mail： yaowen@mail.tongji.edu.cn/qk/85823A/200706/24631993.html7000, 7500, 7570P, 7540Mhttp://cpb.iphy.ac.cn/CN/10.1088/1009-1963/16/6/042https://cpb.iphy.ac.cn/CN/article/downloadArticleFile.do?attachType=PDF&id=1092012006-09-23In this paper, we present a micromagnetic design for high field sensors. The hard layer of the sensors is L10-FePt which is magnetized perpendicularly to film plane and the sense layer is NiFe which is magnetized in the film plane. The magnetization configurations of the hard and sense layers at different external magnetic fields have been simulated. In micromagnetic simulation, the sense field up to one tesla can be reached by using this sensor. We find that whether the sensor has a symmetric or an asymmetric field-sensing window is determined by the coercive field of the hard layer and the demagnetizing field of the sense layer.     

气相色谱/质谱法测定水和沉积物中雄激素与孕激素

建立了气相色谱/质谱联用(GC-MS)技术同时测定水和沉积物中雄激素二氢睾酮、睾丸激素、雄烯二酮和孕激素孕酮的分析方法.分别确定了沉积物微波辅助萃取条件(萃取溶剂、萃取温度和萃取时间)和水样固相萃取条件(固相萃取柱、洗脱溶剂和水样pH值).结果表明:微波辅助萃取最优条件是乙酸乙酯为萃取溶剂,在120℃萃取15 min;以Oasis HLB为固相萃取柱,水样调节至pH4,采用乙酸乙酯为洗脱溶剂,固相萃取效果佳.以三甲基碘硅烷为催化剂,N-甲基-N-三甲基硅基三氟乙酰胺为衍生化试剂,将目标化合物分子结构上的羟基和酮基同步衍生化,并确定了衍生化过程的最佳反应温度为40℃,反应时间为20 min,满足了GC-MS分析该类物质的要求.水和沉积物中4种目标化合物检出限分别为0.1 ～ 0.5 ng/L和0.6 ～ 0.8ng/g,定量限分别为0.4 ～ 1.8 ng/L和1.9 ～2.6 ng/g,加标回收率分别为89.3％ ～ 101.4％和77.3％ ～92.1％,相对标准偏差(RSD)均小于9％.采用本方法对洱海水和沉积物样品进行了分析.     

胆汁返流性胃炎病入血清和胃液中锌、铜、铁、钙含量及意义

采用火焰原子吸收法检测了36例胆汁运流性胃炎病人和30例健康对照者血清和胃液中微量元素Zn、Cu、Fe、及Ca的含量。结果显示，胆汁返流组血清Zn、Cu、Fe含量均明显低于对照组；胃液中Zn、Cu、含量则明显高于对照组；血清和胃液中Ca含量在2组间未见明显差异。该研究为开展胆汁返流性胃炎的病因学和治疗学研究提供了有益的资料。     

差示光度法测定钨钛合金中钛

用高铁容量法测定钨钛合金中钛时,必须先于性介质中将钛与钨分离,此法操作比较烦琐、费时。本文着重研究了对消除主体钨干扰的适宜条件,提出在1.6mol/L及0.6mol/L硫-磷酸介质中,以给定的的磷酸络合钨,应用过氧化氢差示光度法,可不经分离直接测定钛的含量。试验表明,按所取的磷酸量至少能掩蔽90mg钨,且不抑制钛显色,络合物也相当稳定,放置24h吸光度不变。在显色液中可允许0.2mg钒(Ⅴ)、0.5mg铌(Ⅴ)、5mg钼(Ⅵ)、10mg铁(Ⅲ)存在均不影     

硅藻土复合生物反应器处理生活污水

利用硅藻土复合生物反应器处理城市污水．以复配精选硅藻土作为微生物的载体，采用连续流小试实验，考察水力停留时间对硅藻土复合生物反应器处理城市污水的效果，除总氮外，其他出水指标满足我国《城镇污水处理厂污染物排放标准（GB18918--2002）》一级A标准．     

基于STEP中性文件的船舶图形交换技术的研究

在分析DXF图形交换文件，STEP中性文件和IGES初始图形交换规范结构的基础上，介绍了从DXF文件中提取图形信息到SQL Server数据库中，并从数据库中提取数据，定入STEP中性文件。最后从中性文件中获得图形信息，得到IGES文件，实现图形的再现。     

科技期刊青年编辑非专业性素质研究

科技期刊青年编辑是科技出版事业的承继者和未来,高素质的青年科技期刊编辑队伍是科技出版事业繁荣与可持续发展的重要前提.认为专业素质和非专业素质是科技期刊青年编辑素质结构的两大层次,较高的专业技能、良好的外文水平及熟练的计算机能力等专业素质是科技期刊青年编辑的基本素质层次,而良好的思想道德、敬业与专注是科技期刊青年编辑必备的非专业性素质.论述了这3种素质的作用及培养这3种素质的途径.     

Large elastocaloric effect in Ti–Ni shape memory alloy below austenite finish temperature

Solid refrigeration technology based on the elastocaloric effect has a great potential alternative to the conventional vapor compression cooling. Here we report the large elastocaloric effect in Ti–Ni(50 at%) shape memory alloy below its austenite finish temperature A_f under different strain. Both Maxwell's and Clausius–Clapeyron equations are used to estimate the entropy change. The strain-induced entropy change increases with raising the strain and gets a maximum value at a few kelvins below A_f. The maximum entropy changes ?S_(max) are-20.44 and-53.70 J/kg·K, respectively for 1% and2% strain changes. Large entropy change may be obtained down to 20 K below A_f. The temperature of the maximum entropy change remains unchanged before the plastic deformation appears but moves towards low temperature when the plastic deformation happens.