Angular Momentum in the Formation of Disk Galaxies

Within the current framework of disk galaxy formation, we discuss the resulted surface-density profiles according to the theoretical angular momentum distributions (AMDs) presented by Bullock et al. [Astrophys. J.555 (2001) 240(B01)] for the ACDM cosmology in both spherical and cylindric coordinates. It is found that the derived surface density distribution of a disk in the outer region is in general similar to an exponential disk for both the theoretical AMDs. In the central region, the results from both the theoretical AMDs are inconsistent with observations whatever the disk bar-instability is taken into account or not. The cylindric form of the theoretical AMD leads to the bar-instability more easily for a give galaxy than that for spherical AMD, which could result in a more massive bulge. After comparing the model predictions with our Milky Way galaxy, we find that the theoretical AMDs predict larger mass fractions of baryons with low angular momentum than the observed ones, which would lead to the disk sizes to be smaller. Two possible processes which could solve the angular momentum problem are discussed.     

Realization and Comparison of Several Regression Algorithms for Electron Energy Spectrum Reconstruction

To determine the electron energy spectra for medical accelerator effectively, we investigate a nonlinear programming model with several nonlinear regression algorithms, including Levenberg-Marquardt, Quasi-Newton, Gradient, Conjugate Gradient, Newton, Principal-Axis and NMinimize algorithms. The local relaxation-bound method is also developed to increase the calculation accuracy. The testing results demonstrate that the above methods could reconstruct the electron energy spectra effectively. Especially, further with the local relaxationbound method the Levenberg Marquardt, Newton and NMinimize algorithms could precisely obtain both the electron energy spectra and the photon contamination. Further study shows that ignoring about 4% photon contamination would increase error greatly, and it also inaccurately makes the electron energy spectra ‘ddrift＇ to the low energy.     

非竞争性毛细管电泳免疫分析乙肝表面抗原

用硫脲标记乙肝抗体(抗-HBs),基于抗原．抗体高选择性识别,建立了非竞争性毛细管电泳免疫分析乙肝表面抗原的新方法。研究了混合温育时间、缓冲溶液酸度和浓度、进样时间的影响。在5mmol／L Tris-20mmol／L H3BO3-3mmol／L EDTA(pH7．0)的运行缓冲溶液中,游离的标记抗体和抗原抗体复合物在15min内完全分离。HBsAg在4．0—50mg／L范围内与复合物的峰面积呈良好的线性关系;相对标准偏差小于6％;检出限为3．0mg／L。该方法用于乙肝病人血清和正常人血清中HBsAg的测定,结果令人满意。     

司帕沙星的毛细管电泳高频电导法测定

采用毛细管电泳高频电导法检测了司帕沙星。探讨了缓冲液的种类、浓度、添加剂以及操作电压和进样时间等因素对分离的影响。选择3.0mmol LHAc-5.0?H5OH(V V)为电泳介质,分离电压20.0kV,在4min内可实现司帕沙星的分离检测。在优化条件下,司帕沙星的线性范围为6 0～280 0μg mL,检出限为1 9μg mL。在该条件下,片剂中的敷料不干扰测定,可成功测定片剂中的司帕沙星,样品回收率为98.7%～101%。     

毛细管电泳高频电导法测定苦参中的苦参碱和氧化苦参碱

建立了用毛细管电泳高频电导法测定苦参药材中苦参碱和氧化苦参碱的方法。对电泳介质的种类、浓度、pH值以及操作电压和进样时间对分离检测的影响进行了研究。缓冲液为2.0mmol LNa2HPO4 1.0mmol LH3PO4 体积分数为25%乙醇(pH6.0),分离电压为16.0kV时可实现较好的分离与检测。苦参碱和氧化苦参碱的线性范围为:25.0～1.00×103μg mL(相关系数分别为0 987和0.999);RSD(n=6)分别为:2.1%和0.70%;检出限分别为10.0和5.00μg mL;回收率分别为92.7%～99.1%和100%～102%。     

双工作电极-双通道胶束电动毛细管色谱电化学法同时检测4种钙通道阻滞剂

建立了4种钙通道阻滞剂(硝苯地平、尼群地平、尼莫地平和尼卡地平)的双通道胶束电动毛细管色谱电化学检测的分析新方法。采用双工作电极和两台伏安仪,将样品的检测电位分别设定在氧化(1．0V)和还原电位(-1．0V)(vs．SCE),在一个检测池中同时获得4种样品的氧化和还原信息;采用胶束毛细管电色谱法,以硼砂(Na2B4O7)-硼酸(H3BO3)为背景电解质,同时加入十二烷基硫酸钠(SDS)和乙腈组成运行电泳介质,通过优化工作电极、检测电位、缓冲溶液、SDS浓度和乙腈等实验参数,较好地实现了4种钙通道阻滞剂的分离;将该法应用于血药浓度的测定,取得了满意的结果。     

毛细管电泳高频电导法测定粉防己药材中的生物碱

建立了千金藤属植物粉防己中生物碱测定的毛细管电泳高频电导法,以融硅毛细管(150μm×60cm)为分离柱,1mmol LHAc 2mmol LNH4Ac 10mmol Lβ CD 2mmol LSDS缓冲液为电泳介质,分离电压14.0kV,用高频电导法检测,粉防己药材中粉防己碱和去甲粉防己碱可实现定量分离和检测。探讨了缓冲液的种类、浓度、添加剂、分离电压和进样量对分离和检测的影响;在优化条件下的线性范围分别为:粉防己碱12 5～900μg mL,去甲粉防己碱25 0～900μg mL;检出限分别为:粉防己碱6 25μg mL,去甲粉防己碱12.5μg mL;样品加标回收率分别为92.7%～98.9%和95.9%～101%。     

基于疏水性小波分析的膜蛋白结构预测

膜蛋白在细胞膜上具有重要的生理功能,大部分膜蛋白在药物设计、转运蛋白和免疫识别等方面起着关键的作用,从分子水平上预测这类蛋白质的结构具有非常重要的意义。本文提出一种基于氨基酸疏水性小波变换技术预测膜蛋白跨膜区段数目和位置的新方法。以代码为upkb_bovin的膜蛋白为例,对跨膜螺旋区数目和位置的预测分析进行了描述。从膜蛋白数据库中随机抽取36个蛋白质(含跨膜螺旋区232)作为测试集检验小波分析的预测方法,其中226个跨膜螺旋区能被准确预测,准确率为96．8％。结果表明,这种预测方法具有较高的准确性。     

410一2200nm角度调谐BBO参量振荡器

介绍了以Nd:YAG激光器的三倍频光作泵浦源，BBO作非线性光学晶体，在410一2200nm波段可连续调谐的光参量振荡器（OPO）的工作原理和实验装置，测定了其调谐曲线的输出能量，并对实验结果做了分析。