碳糊电极线性扫描伏安法测定α-甲基多巴

α-甲基多巴的降压作用为中等偏强 ,可治疗高血压 ,适用于肾功能不良的高血压病人 [1 ] .现有的分析方法有非水溶液滴定法 [2 ] ,高效液相色谱法 [3] ,分光光度法 [4] .宋又群等 [5]利用流通型生物电极对甲基多巴进行了测定 ,其线性范围仅为 6 .0× 1 0 - 4～ 1 .4× 1 0 - 3 mol/L.用碳糊电极对 α-甲基多巴进行检测 ,未见文献报道 .本文报道 α-甲基多巴在 0 .1 mol/L H2 SO4底液中 ,从 - 0 .2 V( vs.SCE)向正电位方向作阳极化扫描 ,在 0 .6 77V出现 1敏锐的阳极峰 ,峰电流与α-甲基多巴浓度在 5 .0× 1 0 - 7～ 1 .0× 1 0 - 4 mol/…     

吡柔比星的伏安行为及其应用

吡柔比星在 0 .1 mol/L HAc- Na Ac缓冲溶液 (p H4.3)中 ,出现一灵敏的示波极谱导数还原峰 ,峰电位为 - 0 .39V(vs.SCE) ,峰电流与吡柔比星浓度在 2 .0× 1 0 -7～ 4.0× 1 0 -6mol/L范围内成正比。检出限为 1 .0× 1 0 -8mol/L。用于病人尿样的测定。用线性扫描和循环伏安法研究体系的性质。体系属具有吸附性的可逆过程。     

Electrochemical study on interaction of vincristine with tubulin

In Tris (0.005 mol/L)‐NaCl (0.05 mol/L) buffer solution (pH = 7.10), keeping temperature at 37°C, a highly sensitive reduction peak of the antitumor agent was obtained by linear sweep voltammetry. The peak potential is‐1.56 V (vs. SCE). The peak current is proportional to the concentration of vincristine over the range of 2.1 ± 10^?7‐4.2 ± 10^?6 mol/L with the detection limit of 1.0 ± 10^?7 mol/L. The behavior of the binding of vincristine to tubulin was studied. The results showed that the reaction of tubulin dimer with vincristine formed an electrochemically active complex to be 1:2. Its stability constant is 2.5 ± 10¹⁴. The reduction process of the complex is irreversible with adsorptive characteristics.     

A Microcomputer System for Automatic Mode Sweep of Ring Laser Angular Rate Sensor(Ring Laser Gyro)

On the basis of analysis and principles of the operational modes and mode sweep of a ring laser, a microcomputer system for automatic mode sweep of ring laser angular rate sensor is presented. A 0～300 V continuous adjusted power supply system for PZT used to accurately adjust the cavity lens of the ring laser also is described in the paper. The test result shows that the microcomputer system could solve the problem of automatic mode sweep of ring laser successfully.     

高负荷后掠风扇设计若干基本问题

1单级风扇ATS－2（Ad、ncedTransonicStage）设计概述目的是探索总增压比为4．3的两级风扇的设计技术。指标为：设计后掠风扇进口级的缩尺实验件;级增压比2．2;级绝热效率不小于85％;喘振裕度不小于12％。取进口级增压比为2．2,意味着这类单级的增压比已超过大多数于50～80年代设计并服役的涡喷、涡扇发动机前两级轴流级的总增压比,例如WP7发动机。这就需要选用更高的叶尖线速度（相对来流马赫数）。于是这类高性能跨音级的技术特征为级压比高,线速度高,单位迎面流量大,转子叶片后掠或前掠。这时效率的维持主要受到两方面的制约…     

芦丁的电化学伏安行为及其应用

芦丁在0.1mol/L Tris-HCl缓冲溶液(pH=8.3)中产生灵敏的线性扫描极谱峰,峰电位EP=-1.10V(vs.Ag/AgCl).峰电流与芦丁浓度在7×10-7~9.8×10-6mol/L范围内呈良好的线性关系.可用于乌拉尔甘草内黄酮含量的测定.线性扫描和循环伏安法测试表明,该体系属具有吸附性的准可逆过程体系.     

电化学法研究蛋白质和茜素红S的相互作用

在pH 4 .2的Britton Robinson缓冲液中 ,茜素红S(ARS)与牛血清白蛋白 (BSA)能形成一种红色的非电活性的超分子复合物。用线性扫描二阶导数极谱法和循环伏安法对该体系进行了研究 ,复合物的形成使ARS的还原峰电流下降 ,峰电流的下降值同所加的BSA浓度在一定范围内呈线性关系。用于BSA的测定 ,在 8.0× 10 -8～ 1.2× 10 -6mol/L范围内呈线性关系 ,检测限为 4 .3× 10 -8mol/L ,对结合反应机理进行初步的探讨     

线性扫描伏安法同时测定铬、镉、铜

在苯胲类试剂-乙醇-醋酸铵体系中，Cr(Ⅵ)、Cd^2 、Cu^2 都能产生灵敏的阴极络合吸附波。Cr(Ⅵ)的二次导数峰电位在-0．92V(vs．SCE)处，在0．0017～0．67μg／mL范围内与峰电流成正比；Cu^2 的峰电位在-0．21V(vs．SCE)处，在0．0083～5．8μg／mL范围内与峰电流成正比；Cd^2 的峰电位在-0．70V(vs．SCE)处，线性范围为0．0017～0．117μg／mL。这一方法为工业废水中重金属的同时测定提供了可靠、灵敏的检测方法。     

碳糊电极吸附溶出伏安法测定游离钙

基于Ca(Ⅱ)-茜素红S(ARS)络合物在碳糊电极上的还原波,建立了吸附溶出伏安测定游离钙的新方法。在1.5×10-2mol/LKOH-2.0×10-5mol/LARS介质中,Ca(Ⅱ)-ARS络合物在碳糊电极上于-0.89V处产生一吸附还原波。当富集电位为.0.1V,富集时间90s,扫描速度为100mV/s时,该络合物单扫描阴极溶出峰的二阶导数峰电流与游离钙离子浓度在3.0×10-8~2.0×10-6mol/L范围内呈线性关系;检出限为9.4×10-9mol/L。在0.2mol/LHCl中清洗2min,该电极重现性良好。该方法可用于血清、牛奶和自来水中游离钙的测定。     

Influence of magnetic field sweep rate on the hysteresis loops of Ni0.8Fe0.2/Fe0.5Mn0.5 exchange bias bilayer

The influence of the magnetic field sweep rate on the hysteresis loops of exchange bias Ni0.8Fe0.2/Fe0.5Mn0.5 bilayers has been investigated with a vibrating sample magnetometer. It was found that the sweep rate of 13.6 kA/4πms is high enough to bring about obvious changes in the hysteresis loops of the exchange bias bilayer. High sweep rate in the magnetization reversal stage enlarges the coercivity of the sample, while high sweep rate in the saturation state reduces the coercivity. The above phenomena were attributed to magnetic viscosity in the ferromagnetic layer enhanced by the interface exchange interaction and domain magnetization reversals assisted by thermal fluctuation in the antiferromagnetic layer respectively.