对乙酰氨基酚在碳原子线修饰电极上的电化学行为研究

运用循环伏安法研究了对乙酰氨基酚在碳原子线修饰电极上的电化学行为.实验结果表明,对乙酰氨基酚在裸玻碳电极上表现为不可逆的电极过程,而在碳原子线修饰电极上氧化峰和还原峰的电位差为0.048V,为准可逆过程.另外,对乙酰氨基酚在该修饰电极上的检出限为1×10-5mol/L.     

甲磺酸吉米沙星的吸附伏安特性及其应用

在特定缓冲底液（pH6．40）中,甲磺酸吉米沙星（Gemifloxacin mesylate,简称FACTIVE）在汞电极上可以发生还原反应,测得了还原反应的峰电位,该还原峰为典型的吸附峰;测定表明,吸附于滴汞电极上的粒子为甲磺酸吉米沙星的中性分子,通过实验测得了待测物在滴汞电极汞滴上的饱和吸附量,测得了FACTIVE分子在汞滴上吸附后所占电极面积,实验证明待测物中性分子在汞滴上的吸附符合Langmuir吸附等温式;实验表征了吸附系数,25℃时的吸附自由能,电极反应过程中转移电子数,不可逆体系动力学参量,汞滴表面反应速率常数;并通过实验给出了吸附溶出伏安法测定FACTIVE的最佳条件,方法的检出限满足常规分析的要求．     

活性染料废水电凝聚脱色能耗分析

文章在铝阳极和不锈钢阴极的电化学体系中,在恒电流模式下,考察了．活性生红M-3BE模拟废水脱色过程及能耗的影响因素。实验结果表明,电流密度、电解液初始pH值、氯化钠电解质浓度、温度、染料浓度对染料溶液脱色效率影响较大;电流密度、电解液初始pH值、氯化钠与硫酸钠电解质浓度、温度对脱色过程能耗影响显著。在一定实验条件下,染料溶液脱色率可达到98％,能耗117．75kwh／（kg dye）。在不同pH的范围内,活性红M～3BE表现的脱色机理不同,pH4～8为混凝与阴极还原脱色共同作用,pH小于4和大于9则表现为阴极还原脱色为主,且低pH下能耗较低。氯化钠既有助于提高染料废水的脱水效率,又有助于降低脱色过程中的能耗。     

芦丁在玻碳电极上的电化学行为研究

在0.lmol／L B-R缓冲溶液(pH=3．10)中，用循环伏安法可得到芦丁的一对氧化还原峰。峰电位Epc=0．405V，Epa=0．467V(vs．SCE)。实验表明，Rt在玻碳电极上的电极过程为一受吸附和扩散同时控制的准可逆过程。测得还原峰的电子转移系数为0．39，标准速率常数为kn=0．48s^-1。用该法测定了芦丁片中Rt的含量。     

银/乙二胺修饰电极的制备及其对过氧化氢的催化

文章利用电聚合法制备出银/乙二胺修饰电极,并研究H2O2在该修饰电极上的电化学行为,并考察实验条件的影响.实验结果表明:在pH6.7的磷酸盐缓冲溶液中,银/乙二胺修饰电极对H2O2具有良好催化还原作用,H2O2在修饰电极上产生一对较好的氧化还原峰,峰电位分别为Epa=0.344 V,Epc=-0.215 v.线性范围为...     

高斯拟合结合小波降噪处理IMS峰信号

为高效、准确检测离子迁移谱中离子峰的峰位、峰宽和峰高等信息,确定离子峰对应的物质种类和浓度,研究基于小波的离子迁移谱信号的去噪方法和基于高斯拟合方法的离子迁移谱信号的重构技术,给出在离子迁移谱检测爆炸物的应用中的测试结果.实验表明,基于高斯拟合结合小波降噪的方法来分析离子迁移谱信号,能够准确还原因为信号峰的重叠而消失的离子峰,提高应用离子迁移谱定性分析物质种类的能力.     

CuHCF/Pt的制备及其电化学性质

通过实验选择了制备铁氰化铜修饰铂电极(CuHCF/Pt)的最佳条件,并用循环伏安法考察了CuHCF/Pt对一价阳离子的选择性及VC在该电极上的电化学行为.实验结果表明,CuHCF/Pt在0.4~1.0 V(vs.SCE)范围内有一对可逆性良好的氧化还原峰,该电极对K+有较好地选择性且对VC有催化氧化作用.     

Fe-C微电解处理染料废水综合实验设计北大核心

为了增强本科生的水环境保护意识,拓展化工多领域视角,设计了一种石油基Fe-C微电解填料处理染料废水的教学实验。该填料以石油化工产品为碳源,以还原铁粉为铁源,在短时间内实现对日落黄染料分子的降解,反应900 s时即可将色度完全消除,化学需氧量(COD)降解率能达到79.19%。通过Fe-C微电解填料与Fenton体系联用,染料分子降解速率与程度显著提升,降解450 s时,COD降解率可提升至94.17%。整个实验流程由学生主导,在实验准备阶段学生分工调研,实验方案由学生自主设计,实验过程由学生分组协作完成,充分发挥学生的自主创新意识,让学生从石油化工领域出发,拓展学科视野,培养绿色化工意识,承担保护水环境责任。     

线性扫描伏安法测定维生素B2

运用循环伏安法(CV)、线性扫描伏安法(LSV)等方法研究维生素B2在多壁碳纳米管修饰电极上的电化学行为,建立一种直接测定维生素B2的电化学分析方法.与裸玻碳电极相比,多壁碳纳米管修饰电极显示出很好的催化作用,维生素B2在修饰电极上得到一对灵敏的氧化还原峰(Epa=-0.222 V,Epc=-0.317 V),且氧化还原峰电流显著增强.在优化实验条件下,还原峰电流与维生素B2浓度在3.0×10-6～2.0×10-5mol·L-1有良好的线性关系,检出限为1.0×10-6mol·L-1.对1.0×105mol·L-1维生素B2溶液平行测定10次的相对标准偏差(RSD)为4.2%.用此方法测定维生素B2片中维生素B2的含量,结果令人满意.     

含铕硅钼钨多金属氧酸盐水溶液的电化学及电催化还原

采用循环伏安法,研究了含铕硅钼钨多金属氧酸盐(简写为Eu(SiMo6W5)213-)水溶液的电化学性质,结果表明,在0.6～0.5V的电位区间内,Eu(SiMo6W5)213-呈现了四对准可逆的氧化还原峰,其氧化还原峰电位随着溶液pH的升高而负移,催化活性实验结果表明,在酸性溶液中该化合物对NaNO2、H2O2以及IO3-和BrO3-的还原反应具有良好的催化作用。     

Response strength and temporal control in fixed-interval schedules

Pigeons responded in a two-component peak procedure in which the components differed in terms of reinforcement magnitude (Experiment 1), immediacy (Experiment 2), or probability (Experiment 3). The prediction of behavioral momentum theory that responding in the relatively richer component should be more resistant to change was tested by (1) presenting response-independent food in the intervals between components according to a variable-time (VT) schedule, (2) prefeeding, and (3) extinction. In all the experiments, peak location in baseline occurred earlier, relative to the schedule value in the richer component. Peak response rate was more resistant to change in the richer component during the VT and prefeeding tests, and change in peak rate was more sensitive to differential reinforcement than change in overall response rate. Changes in measures of performance on peak trials during the disruptor tests were partially consistent with predictions of the behavioral theory of timing. The results suggest that peak response rate provides a more sensitive index of resistance to change for fixed-interval schedules than does overall response rate and that reinforcement strengthens both peak responding and temporal control.     

维生素B12在玻碳电极上的电化学行为研究

在0．1mol／LHAc—NaAc缓冲溶液(pH=4．54)中，用循环伏安法可得到维生素B12的两个还原峰。峰电位EP1=-0．458V，EP2=-0．831V(vs．SCE)。实验表明，维生素B12在玻碳电极上的电极过程为一受吸附控制的不可逆过程。测得还原峰的电子转移系数为0．3，标准速率常数为ks=2．40s^-1。用该法测定了维生素B12针剂中维生素B12的含量，结果与标示含量相吻合。     

三种蟋蟀鸣声特征的比较

录制分析了陕西省三种常见蟋蟀的雄性鸣声特征.结果表明:贝氏斗蟋鸣声中一个音节所含脉冲数不等,多为8或9个,音节持续时间较长(约203 ms),主峰频率为4472Hz;长鄂斗蟋鸣声中一个音节所含脉冲数多为8个,主峰频率为4162 Hz;多伊棺头蟋鸣声的时域波形较为规则,每个音节皆由2个脉冲组成,音节持续时间较短(约32 ms),主峰频率为4810 Hz。两种斗蟋的鸣声表现出一定的相似性和不同之处,而与多伊棺头蟋鸣声的差别较明显。鸣声之间的差异可以作为种类鉴别的依据。     

铜(Ⅱ)-头孢唑啉钠络合物吸附波的研究与应用

在pHl0的NH3-NH4C1缓冲溶液中，Cu(Ⅱ)-头孢唑啉钠络合物在单扫描示波极谱仪上产生一灵敏的还原峰，其一次导数峰电位为-0．30V(vs．SCE)，峰电流与铜浓度在0．005—0．3mg／L范围内呈线性关系，检出限为0．0025mg／L。将该波用于人发及硫酸镍中铜含量的测定，并就极谱波的性质进行了探讨。     

Temporal generalization and peak shift in humans

Three experiments investigated temporal generalization in humans. In Experiment 1, a peak shift effect was produced when participants were given intradimensional discrimination training. In Experiment 2, after training with a standard S1 and generalization testing with an asymmetrical series of durations, generalization gradients moved toward the prevailing adaptation level. In Experiment 3, generalization gradients showed a central tendency shift and moved away from the S1 and toward the mean of the test series (of 11 stimulus durations) after participants received training with S1 and S2 durations that in one condition were the 2nd and 4th and in another condition were the 4th and 2nd stimuli in the series, respectively. The results were inconsistent with an absolute account of peak shift but were consistent with an adaptation level account of peak shift.     

Statistical extremes and peak factors in wind-induced vibration of tall buildings

In the structural design of tall buildings, peak factors have been widely used to predict mean extreme responses of tall buildings under wind excitations. Vanmarcke’s peak factor is directly related to an explicit measure of structural reliability against a Gaussian response process. We review the use of this factor for time-variant reliability design by comparing it to the conventional Davenport’s peak factor. Based on the asymptotic theory of statistical extremes, a new closed-form peak factor, the so-called Gamma peak factor, can be obtained for a non-Gaussian resultant response characterized by a Rayleigh distribution process. Using the Gamma peak factor, a combined peak factor method was developed for predicting the expected maximum resultant responses of a building undergoing lateral-torsional vibration. The effects of the standard deviation ratio of two sway components and the inter-component correlation on the evaluation of peak resultant response were also investigated. Utilizing wind tunnel data derived from synchronous multi-pressure measurements, we carried out a wind-induced time history response analysis of the Commonwealth Advisory Aeronautical Research Council (CAARC) standard tall building to validate the applicability of the Gamma peak factor to the prediction of the peak resultant acceleration. Results from the building example indicated that the use of the Gamma peak factor enables accurate predictions to be made of the mean extreme resultant acceleration responses for dynamic serviceability performance design of modern tall buildings.     

Electrochemical behaviors of lomefloxacin at a single-wall carbon nanotube-modified electrode and its interaction with bovine serum albumin

The electrochemical behaviors of lomefloxacin at a single-wall carbon nanotube-modified glassy carbon electrode have been investigated by cyclic voltammetry. In a Britton-Robinson buffer (pH 4. 5 ), lomefioxacin yields a sensitive and well-defined oxidation peak at ca. 1.24 V (vs. SCE) on the modified electrode. Compared with the bare glassy carbon electrode, the oxidation peak current of lomefloxacin significantly increases and the oxidation peak potential positively shifts. Under the optimal conditions, the interaction of lomefloxacin with bovine serum albumin is also investigated. The results indicate that an electrochemically inactive supramolecular complex is formed and the formation of complex between lomefloxacin and bovine serum albumin is an intercalation mechanism. The proposed methods offer a reference for the studies on the biological effects and action mechanism of lomefioxacin with albumins in vivo.     

气相色谱法对壬基酚聚氧乙烯醚裂解条件的选择

壬基酚聚氧乙烯醚是一种商用的非离子表面活性剂,在油砂分离过程中起到了很大的作用。因其对环境的影响,所以对其含量的测定是非常有必要的。利用氢碘酸对壬基酚聚氧乙烯醚进行裂解,通过气相色谱对裂解物壬基酚的峰面积或者峰高找到最佳的裂解条件,并且重现性很好,精确度达到3%,并通过气-质联用对裂解物进行定性,裂解条件的选择对定量提供了方法。     

基于树莓派的实时心脏病辅助诊断

依据心电图特征参数R峰面积与S峰面积比,对正常、异常心电图进行快速二分类以提高心电分类效率和准确率。通过MIT-BIH数据库统计分析,正常心电图R峰面积与S峰面积比远大于异常心电图中的面积比值。在QRS波群检测中,改进QRS波群起止点检测算法,将移动窗口积分法、距离最大值法与斜率突变法3种方法加权平均结果作为QRS起止点最终检测结果,弥补单一算法的不足,提高起止点检测精确度,为面积比计算及后续心脏病辅助诊断提供可靠前提。基于低功耗、便携的树莓派平台实现算法,以树莓派Raspbian系统自带的Python为工具,构建了一个便携、实时的心电辅助诊断平台。