Effects of a Constant Magnetic Field on the Electrochemical Reactions of Quercetin

The paper presents a study of the effect of a constant magnetic field (CMF) on the basic processes of quercetin electrochemical reactions. According to the observation made in previous studies, the presence of a double bond in the C-ring of quercetin enhances the antioxidant properties of that compound, whereas the presence of −OH groups also affects the antioxidant properties. Using cyclic voltammetry it was found that the constant magnetic field improves the efficiency of quercetin electrooxidation, especially of the third stage of the process, i. e. the stage in which the oxidation of the OH groups in the A-ring is the most difficult. The use of HPLC confirmed the electrochemical measurements and the results of cyclic voltammetry studies. The beneficial effect of the magnetic field on the efficiency of quercetin oxidation was confirmed by the results of impedance spectroscopy measurements.     

Human skin thermal properties determination using a calorimetric sensor

Journal of Thermal Analysis and Calorimetry - The purpose of the calorimetric sensor developed is to measure the heat flux transmitted by conduction between the human body surface and a thermostat...     

Preparation of magnetic attapulgite/polypyrrole nanocomposites for magnetic effervescence‐assisted dispersive solid‐phase extraction of pyrethroids from honey samples

In this work, a novel extraction technique based on the effervescence‐assisted dispersion and magnetic recovery of attapulgite/polypyrrole sorbents was developed for determining the concentrations of five pyrethroids in honey samples. The magnetic nanoparticles were synthesized by a one‐pot method. Several experimental parameters that affected the extraction efficiency, including the dispersion conditions, pH, ionic strength, and desorption conditions, were investigated. Under optimal conditions, the calibration curves for the five pyrethroids in honey samples exhibited good linearity, with r² values ranging from 0.9979 to 0.9990. The limits of detection varied between 0.21 and 0.34 µg/L. Satisfactory recoveries of 81.42–106.73% with intra‐ and interday relative standard deviations of less than 6.94 and 10.89%, respectively, were obtained. Moreover, the sorbents exhibited acceptable batch‐to‐batch repeatability in the range of 5.06–15.01%, and each sorbent could be reused for up to four extraction cycles without a significant loss in the extraction recovery.     

A novel heterogeneous Co(II)-Fenton-like catalyst for efficient photodegradation by visible light over extended pH

Science China Chemistry - A novel CoII-Fenton-like heterogeneous catalyst, (H3O)2[CoII(phen)(H2O)2]2[MoVI5O15(PO4)2]·4H2O (phen=1,10-phenanthroline, C12N2H8) (1), is synthesized and utilized...     

Skin Friction Reduction of Hypersonic Body by Supersonic Layer

Fluid Dynamics - Both numerical methods and wind tunnel tests were used to reduce skin friction for a hypersonic body. A hypersonic cone was tested under three different free-stream flow...     

室温下镀钯多壁碳纳米管对苯的气敏响应特性

在酸氧化后的多壁碳纳米管上化学还原镀钯,用水将镀钯后的碳管清洗至中性并配制成悬浊液,将悬浊液旋涂在真空溅射的叉指金电极表面,干燥后作为气敏膜,把气敏膜暴露于一定浓度的苯气体中,检测传感器的电流变化,并计算其灵敏度。镀钯后的多壁碳管在室温下对苯响应和回复迅速,电导变化与苯气体的浓度呈良好的线性关系,其线性回归方程y=0.0041x 0.1288,r=0.9546。Pd颗粒对苯分子和碳管壁结构缺陷间的电子转移的促进作用可能是多壁碳管镀钯后产生良好气敏响应的原因。     

人体胆结石成分及无机元素的分析探讨

本文运用三种仪器对胆结石中无机元素含量和成分进行测定,对照标准谱图分析.四个样品的主要成分均为胆固醇,含有较多的元素依次为Ca、Na、P、K和Mg.通过所得结果对胆固醇的成因、无机元素含量变化的作用进行了讨论.     

1.3 GHz超导腔磁通排出效应研究

设计并搭建了一套高精度的磁场测量和补偿系统,并结合中国科学院高能物理研究所(IHEP)的2K超导腔垂直测试平台对1.3 GHz单加速间隙超导腔的磁通排出效应开展了实验研究:利用研制的磁场测量和补偿系统能够精密地测量超导腔赤道位置磁场,并能够将磁场补偿至小于5.0×10-8 T;并对超导腔不同表面温度梯度下的磁通排出效应进行了测量分析;对钉扎了磁场的超导腔进行了射频性能测试,研究了超导腔电阻对磁通钉扎的敏感度,以及在不同电场梯度下超导腔的表面电阻变化情况。结果表明,研制的高精度磁场测量和补偿系统能够满足超导腔磁通排出研究的需求;高的超导腔表面温度梯度有利于磁通的排出;磁通钉扎电阻的敏感度随着加速电场梯度的增加而增大,导致超导腔的性能下降。此实验研究也为后续超导腔的研制奠定了一定基础。     

Sturmian Ground States in Classical Lattice–Gas Models

Journal of Statistical Physics - We construct for the first time examples of non-frustrated, two-body, infinite-range, one-dimensional classical lattice–gas models without periodic...     

In-situ SiN combined with etch-stop barrier structure for high-frequency AlGaN/GaN HEMT

The etch-stop structure including the in-situ SiN and AlGaN/GaN barrier is proposed for high frequency applications.The etch-stop process is realized by placing an in-situ SiN layer on the top of the thin AlGaN barrier.F-based etching can be self-terminated after removing SiN,leaving the AlGaN barrier in the gate region.With this in-situ SiN and thin barrier etch-stop structure,the short channel effect can be suppressed,meanwhile achieving highly precisely controlled and low damage etching process.The device shows a maximum drain current of 1022 mA/mm,a peak transconductance of 459 mS/mm,and a maximum oscillation frequency(fmax)of 248 GHz.