高效液相色谱-串联质谱法结合多糖衍生物手性固定相拆分氰戊菊酯

建立了以多糖衍生物为手性固定相的高效液相色谱-串联质谱(HPLC-MS/MS)直接拆分氰戊菊酯对映体的方法。在反相液相色谱条件下,考察了手性固定相的种类、流动相组成、柱温、流速对氰戊菊酯4个立体异构体分离的影响。同时,利用热力学方法对氰戊菊酯的立体异构体与固定相之间的色谱保留和分离的热力学机理进行了探讨。结果表明:采用Lux Cellulose-3(纤维素-三(4-甲基苯甲酸酯))手性色谱柱,在以流动相为乙腈-水(5 mmol/L甲酸铵)=(55:45,V:V)流速0.4 mL/min,柱温30℃的条件下,可在14 mins内实现氰戊菊酯4个立体异构体的基线分离。拓展了HPLC-MS/MS在菊酯类手性农药对映体分离及检测上的应用。     

Lithium difluoro(oxalato)borate as an additive to suppress the aluminum corrosion in lithium bis(fluorosulfony)imide-based nonaqueous carbonate electrolyte

Journal of Solid State Electrochemistry - Lithium bis(fluorosulfony)imide (LiFSI) is a promising alternative lithium salt to replace lithium hexafluorophosphate (LiPF6) due to its high conductivity...     

Static headspace‐multicapillary column with gas chromatography coupled to ion mobility spectrometry as a simple approach for the discrimination of crude and processed traditional Chinese medicines

The processing procedure can alter the nature and chemical transformation of traditional Chinese medicine to accommodate different clinical dispensing and preparation requirements. In this study, static headspace‐multicapillary column with gas chromatography coupled to ion mobility spectrometry was developed for the rapid and sensitive discrimination of crude and processed traditional Chinese medicine. Using Radix Paeoniae Alba as a traditional Chinese medicine model, the combined power of this approach was illustrated by classifying the crude and processed Radix Paeoniae Alba samples into two main categories. The contents of the main components in Radix Paeoniae Alba varied significantly. The established method could promote the use of ion mobility spectrometry in intrinsic quality control and differentiation of herbal medicines from other processed products or preparations.     

On the force field optimisation of $$\beta$$ β -lactam cores using the force field Toolkit

Journal of Computer-Aided Molecular Design - When employing molecular dynamics (MD) simulations for computer-aided drug design, the quality of the used force fields is highly important. Here we...     

Sustained and Controlled Release of Volatile Precursors for Chemical Vapor Deposition of Graphene at Atmospheric Pressure

Precursors and catalysts play vital roles in chemical reactions. Considerable efforts have been devoted to the investigation of catalysts for graphene growth by chemical vapor deposition in recent years. However, there has been little research on precursors because of a lack of innovation in term of creating a controllable feeding method. Herein, we present a novel sustained and controlled release approach, and develop a convenient, safe, and potentially scalable feeding system with the assistance of matrix materials and a simple portable feeder. As a result, a highly volatile liquid precursor can be fed accurately to grow large-area, uniform graphene films with optimal properties. This feeding approach will further benefit the synthesis of other two-dimensional materials from various precursors.     

高能粒子对托卡马克气球模稳定作用的数值分析

用数值方法分析了高能捕获粒子对托卡马克气球模不稳定性的影响.利用变步长RKF积分方法求解了相应的微分-积分方程边值问题.数值结果表明,气球模不稳定区随高能粒子压强增大而缩小,充分说明了高能捕获粒子能部分或全部抑制气球模不稳定性.     

Angular spectrum theory to calculate coupling efficiency in rectangular waveguide resonators

Coupling efficiency of the rectangular waveguide resonators are discussed in terms of the method of angular spectrum theory. Under the condition given in the paper, the coupling coefficients for the EH₁₁ mode in the rectangular waveguide resonator are presented as a function of mirror curvature and position. It is shown that there exist two special geometries to provide low coupling efficiency. The method can be applied to the other modes.     

稀土元素在长江口及邻近陆架表层沉积物中的分布及物源示踪研究

长江口邻近陆架表层沉积物中稀土元素含量及组成表明其主要来源为中国大陆陆源物质.轻重稀土元素比值对于区分长江和黄河流域来源物质具有一定的示踪意义,古黄河三角洲以较低的轻重稀土元素比值为特征,而长江来源物质以相对较高的轻重稀土比值为特征,沉积物粒度和Cl含量不是控制沉积区内稀土元素分馏的主要因素.通过聚类分析将研究区域划分为长江口近岸区和东海北部陆架区两个分区,黄海沿岸流、长江冲淡水以及台湾暖流是造成分区的关键水动力因素.分区内常量和微量元素以及同位素组成皆表现为不同程度差异,长江口近岸区化学组成和长江流域物质基本一致,东海北部陆架区与黄河流域物质比较接近.     

纤维加强金属基复合材料热机械疲劳模型的研究进展

纤维增强金属基复合材料的热机械疲劳(thermomechanical fatigue 简称TMF)特性的研究在近年受到高度重视.本文根据国内外近期进行的理论研究以及获得的主要成果作一概要介绍.对于热机械循环特性,主要介绍基于细观力学方法的轴向性质模型,以及基于断裂与损伤理论的横向性质模型.对于热机械疲劳性能研究,结合横向性质导出两种热机械疲劳模型,然后分析基体的细观结构对疲劳寿命的影响.