数学实验课的教学模式研究

本文主要探讨工科数学教学中数学实验课的多个层次和开设数学实验课的几种方式 ,并且介绍我们的一些具体做法和面临的一些问题     

气相色谱－三重四极杆质谱法测定动物源性食品中砜吡草唑残留量

建立了动物源性食品中砜吡草唑残留量的气相色谱－三重四极杆质谱检测方法。猪肉、猪肝、鸡肉、鸡肝、牛奶和鸡蛋中的砜吡草唑用乙腈提取,经乙二胺-N-丙基硅烷化硅胶、十八烷基键合硅胶和无水硫酸镁去除杂质,离心后取上清液氮吹至干,加入丙酮复溶、过滤后经气相色谱－三重四极杆质谱检测,外标法定量。通过对仪器条件、提取溶剂和净化方式等进行优化,确定最合适的前处理方法和仪器条件。对样品的基质效应进行考察,发现6种基质中砜吡草唑的基质效应均小于20%,为弱基质效应,无需采取补偿措施。在优化实验条件下,砜吡草唑在0.5 ~ 100 μg/L范围内线性关系良好,相关系数为0.999 5。空白样品在4个加标水平下的平均回收率为85.8% ~ 106%,相对标准偏差（n = 6）为3.1% ~ 6.8%,方法定量下限为0.001 mg/kg。采用该方法对50个动物源性食品进行测定,在1个牛肉样品和1个羊肉样品中检出砜吡草唑。该方法操作简单、灵敏度高、准确性好,适用于动物源性食品中砜吡草唑的检测,可为砜吡草唑在动物源性食品中的风险监控提供技术支撑。     

二氧化铅修饰玻碳电极的镀膜/循环伏安法制备及电催化性能

采用镀膜/循环伏安法制备了PbO2修饰玻碳电极.在Pb(NO3)2溶液中,在-0.7 V 将Pb膜沉积在玻碳电极表面,然后在5 mol/L NaOH溶液中以100 mV/s速度在-1.0～1.0 V循环伏安扫描20次,PbO2膜均匀沉积在玻碳电极表面.采用交流阻抗法监控电极修饰每一过程,环境扫描电镜表征电极表面形貌.探讨了PbO2膜的沉积机理及其电化学行为,表面活性位点覆盖量为7.5×10-10 mol/cm2.PbO2修饰电极对H2O2电氧化表现出较高催化活性,起始氧化电位低至0.1 V,考察了影响催化活性的因素.计时电流法测定H2O2 (工作电位0.40 V),响应时间小于2 s; 线性范围为5.0 ×10-6 ～ 5.5×10-4 mol/L;检出限1.1×10-6 mol/L (信噪比为3).在实际水样中H2O2测定结果满意.电极在室温环境下储存30 d,其催化活性基本不变.该修饰电极制备工艺简单、重现性良好、稳定性高.     

扭Heisenberg-Virasoro代数上Hom-李代数结构

Hom-李代数是一类满足反对称和Hom-Jacobi等式的非结合代数.扭Heisenberg-Virasoro代数是次数不超过1的微分算子代数的中心扩张,它是一类重要的无限维李代数,与一些曲线的模空间有关.文章主要研究扭Heisenberg-Virasoro代数上Hom-李代数结构,确定了扭Heisenberg-Virasoro代数上存在非平凡的Hom-李代数结构.     

色谱研究的最新进展

作为本期《色谱》的聚焦专栏评述,笔者主要介绍国内外学者在2010年3月和4月间发表的一些研究工作［1-9］,内容集中在色谱研究和应用的两个方面:新型色谱材料和方法技术的开发［1－5］;色谱在蛋白质组学分析中的新应用［6,7］。另外,近期也有不少关于微流控分析应用的具有特色的工作［8］,由于篇幅限制就不在这里详细介绍。     

On-line sensing of aluminium in zinc hot-dip galvanizing baths using novel techniques

Measurement and control of the dissolved aluminium levels in zinc hot-dip galvanizing baths, is of great importance to the steel industry. Current attempts at the cost-effective production of an aluminium sensor, for use in molten zinc, have not proved to be very successful. Possible sensor systems, based upon two contrasting electrolytes are proposed within this paper. A sensor based upon thein-situ formation of sodium aluminium chloride, through D.C charging, is proposed. The charging process and EMF versus time relationship, for different aluminium concentrations, has been investigated. A second system, based upon the trivalent ion conducting electrolyte, aluminium tungstate, has also been studied. Aluminium tungstate, Al₂(WO₄)₃, has been prepared by a simple calcination step. Modification of the structure of the electrolyte, to improve its conduction properties, has been investigated. Paper presented at the 6th Euroconference on Solid State Ionics, Cetraro, Calabria, Italy, Sept. 12–19, 1999.     

Improved detection limits for electrospray ionization on a magnetic sector mass spectrometer by using an array detector

Array detection was compared with point detection for solutions of hen egg-white lysozyme, equine myoglobin, and ubiquitin analyzed by electrospray ionization with a magnetic sector mass spectrometer. The detection limits for samples analyzed by using the array detector system were at least 10 times lower than could be achieved by using a point detector on the same mass spectrometer. The minimum detectable quantity of protein corresponded to a signal-to-background ratio of approximately 2∶1 for a 500 amol/μL solution of hen egg-white lysozyme. However, the ultimate practical sample concentrations appeared to be in the 10–100 fmol/μL range for the analysis of dilute solutions of relatively pure proteins or simple mixtures.     

三齿NS2型配体Cu(Ⅱ)配合物的合成、光谱性质及电化学性质

A variety of complexes Cu(NS₂)(Im)(NO₃)₂ and Cu(NS₂)(Py)(NO₃)₂ where NS₂=HN(CH₂CH₂SR)₂(R=CH₃CH₂CH₂, (CH₃)₂CH,CH₃CH₂CH₂CH₂ and (CH₃)₂CHCH₂), have been synthesized and characterized by elementary analyses, molar conductivity, IR, UV/Vis and ESR spectra as well as by electrochemical methods. The new complexes exhibit exceptionally high redox potentials(500～580 mV) and complexes for HN(CH₂CH₂SCH(CH₃)₂)₂ exihibit rather hyperfine splitting constants(a_‖<70G) in the powder ESR spectra, which are close to those for the blue copper proteins.     

天花粉蛋白C-端顺序的测定

采用肼解法、乙内酰硫脲法和羧肽酶法检测了天花粉蛋白的C-端氨基酸有二,分别为Met和Ala借计算机辅助的羧肽酶法, 测定了天花粉蛋白C-端顺序, 其结果显示C-端是非均一的, 有两个未端, 分别为-ArgAsnAsnMetOH和-ArgAsnAsnMetAlaOH.这些结论已经从天花粉蛋白的溴化氰降解物中获得游离的Ala, 和从该蛋白的胰蛋白酶酶解物中分离得与该两顺序相符的两个碎片而完全证实.     

Schiff碱药物对产气杆菌代谢抑制的热力学研究

用微量热法测定产气杆菌在不同温度条件下受到Schiff碱药物抑制的热谱曲线, 根据其指数生长期的热谱信息, 确定它在不同温度条件下的生长速率常数和反应活化能, 找出了该细菌的最佳生长温度。同时借用化学反应中的过渡态理论, 得到一系列热力学参数, 对细菌在受到抑制时的生长代谢进行了热力学分析。