Application of step-scan FTIR to the research of quantum cascade lasers

The principle of step-scan Fourier transform infrared (FTIR) spectroscopy is introduced. Double modulation step-scan FTIR technique is used to obtain the quantum cascade laser's stacked emission spectra in the time domain. Optical property and thermal accumulation of devices due to large drive current are analyzed.     

信号处理技术在重叠化学信号解析中的应用*

重叠峰解析是目前分析化学中亟须解决的一个重要问题,化学计量学用于重叠峰解析就是借助某些数学或统计学方法,把通过化学方法和仪器未能完全分离的复合量测信号分解成几个单儿组分的信号,从而从重叠谱中获取每个组分的相关信息。本文综述了几种常见信号处理技术在重叠化学信号分辨中的应用,引用文献146篇。     

动能歧视(KED)-电感耦合等离子体质谱(ICP-MS)法测定贵州沉积型稀土矿中16种稀土元素

贵州沉积型稀土矿主要含有高岭土-锐钛矿石等矿物,存在高含量Si、Al、Fe、Ti、Zr等难溶基体元素,采用高压密闭微波消解法处理难以将其完全溶解,易使测定结果偏低,需再次消解或进一步电热板敞开酸溶处理,方法耗时长,不利于大批量样品检测需求。同时电感耦合等离子体质谱法(ICP-MS)在测定稀土元素时存在基体效应和质谱干扰,影响了检测数据的准确性。本文采用过氧化钠熔融分解样品,熔融物冷却后引入三乙醇胺溶液,在碱性溶液中,大量基体元素与三乙醇胺形成稳定配合物,并与大量溶剂钠盐存于溶液中,稀土元素与Ca、Mg、Sr、Ba等留存于沉淀,经过滤,实现稀土元素与大量基体元素分离,随后沉淀用(1+1)硝酸复溶,并以103Rh和185Re为在线注入内标协同降低基体干扰;启用动能歧视(KED)模式以降低测定过程中潜在的质谱干扰。实验结果表明:高压密闭微波消解法消解液浑浊有残渣,溶矿耗时长,测试结果偏低,碱溶法酸化后溶液清亮透明,稀土元素测定值准确性高;经条件试验,采用10%三乙醇胺溶液提取能较大降低基体干扰;启用KED模式可降低测定过程中的质谱干扰,且准确度优于STD模式;碱溶法方法检出限为0.008μg/g~0.049μg/g,测定下限为0.034μg/g~0.195μg/g,相对标准偏差RSD在0.78%～10.2%之间,相对误差RE在0.0225%~13.5%之间。经实际样品验证,碱熔法较适用于贵州沉积性稀土矿中16种稀土元素的测定。     

小波变换及其在化学中的应用

简介了小波变换的原理，综述了从１９９２年到１９９８年９月小波变换在化学中的应用。引参考文献６５篇。     

重视演示实验 提高化学教学质量

演示实验是使学生获取知识、活跃思维、激发兴趣、培养能力的重要手段。它既可以及时提供必要的化学事实供学生验证所学的理论知识并加强记忆,又可以使学生学到化学实验的技巧,还可以使教学按辩证唯物主义认识论的原理进行,事半功倍地帮助学生形成概念、掌握知识、培养观察现象、分析问题、解决问题的能力,从而提高化学教学质量,圆满完成教学任务。     

抗癌新药染料木素的电化学行为及其应用研究

研究了新型抗癌药物染料木素在pH=1～12水溶液中的极谱行为。在不同pH范围内得到了染料木素的四个还原波。研究证实在ph＜5的条件下所获得的P1波及5＜pH＜10介质中获得的P2波为染料木素中性分子的两电子,单质子及其电离形成一价阴离子的两电子,单质子不可逆吸附还原波。在pH＜6的条件下所获得的P3波属于染料木素解离形成阴离子的不可逆强吸附前波,而P4波则属于染料木素在碱性介质中解离形成高价阴离子的不可逆吸附还原波。此外通过邻苯三酚自氧化产生活性氧自由基的再还原,对染料木素清除活性氧自由基的能力进行了研究,从电化学的角度对其药理机制进行了阐述。     

Application of wavelet transform in pulsed ultrasonic modulation voltammetry

In this study, wavelet transform was employed to achieve the different current components in pulsed ultrasonic modulation voltammetry. It was found that the pulsed sonovoltammograms could be decomposed into wavelet approximations and wavelet details by projecting wavelet transform on the signals in question. Since wavelet approximations with a certain scale parameter may retain the waveform of the original signal, the current components resulted from ultrasound "on" and "off" in pulsed sonovoltammograms could be separated at a certain scale parameter in multiplying wavelet approximation. With this method, the current components corresponding to pulse-on and pulse-off can be recorded separately without the external data acquisition system used in general modulation voltammetric measurements. The current difference between the two states was found to be proportional to the concentration of the electro-active species. The analytical usefulness of this approach was exploited for determination of ferrocyanide ion at sub-micromolar concentrations.     

气相色谱-石墨炉原子吸收光谱联机研究及有机硒的形态分析

本文采用自制的接口直接连接气相色谱和石墨炉原子吸收光谱仪,建立了有机硒的形态分析方法。通过对气相色谱和原子吸收光谱的实验条件的优化选择,测定二甲基硒和二乙基硒的检出极限分别达到0.14ng和0.28ng,方法的相对标准偏差分别为1.9％和4.7％。标准曲线在0～20ng范围内线性良好。     

A new SAIR model on complex networks for analysing the 2019 novel coronavirus (COVID-19)

Nonlinear Dynamics - Nowadays, the novel coronavirus (COVID-19) is spreading around the world and has attracted extremely wide public attention. From the beginning of the outbreak to now, there...     

Development of a Two‐Photon Fluorescent Probe for Imaging of Endogenous Formaldehyde in Living Tissues

Investigation of the physiological and pathological functions of formaldehyde (FA) are largely restricted by a lack of useful FA imaging agents, in particular, those that allow detection of FA in the context of living tissues. Herein, we present the rational design, synthesis, and photophysical property studies of the first two‐photon fluorescent FA probe, Na‐FA . Importantly, the highly desirable attributes of the probe Na‐FA (such as a very large turn‐on signal (up to 900‐fold), a low detection limit, and a very fast onset imparted by the unique design aspects of the probe), make it possible to monitor endogenous FA in living tissues for the first time. Furthermore, sodium bisulfite was identified as a simple and convenient inhibitor of FA within biological environments.