Positivity of the temperature for phase transitions with micro-movements

We focus on the thermodynamic consistency of a class of phase change models recently proposed by Frémond [Non-smooth Thermomechanics. Springer, Berlin, 2002]. By establishing a maximum principle, we prove that, under rather weak assumptions on data, the temperature remains almost everywhere strictly positive. This general result applies to all dissipative models of this class that have been taken into account in the literature.     

Techno-economic analysis of new integrated system of humid air turbine,organic Rankine cycle,and parabolic trough collector

Journal of Thermal Analysis and Calorimetry - Microgas turbines are one of the most well-known technologies for distributed generation. Unfortunately, their efficiency is not as high as it should...     

基于二维重组和动态窗格的水质检测紫外-可见光谱去噪算法

立足于成功研制的紫外-可见光谱水质检测多参数测量系统,针对紫外-可见光谱水质多参数原位实时检测在精度、灵敏度、稳定性等方面的实际需要,开展了基于二维重组和动态窗格的水质检测紫外-可见光谱去噪算法的研究,以此提高紫外-可见光谱水质检测的测量精度。光谱法水质检测系统通常使用工业级低成本光谱仪,其输出光谱包含明显的非平稳噪声。传统去噪法难以在滤除噪声的同时保留谱线细节。而且,原位实时水质检测条件下,被测水样可能快速变化,传统去噪法中常用的多次采样求均值法将产生额外的测量误差。引入的去噪算法通过对水样光谱进行等间隙连续采样,将光谱数据张成由光谱轴和时间轴构成的二维矩阵,经过二维小波变换后,设置一个可变宽度的窗格在系数矩阵中水平滑动,使用窗格内的小波系数计算得到动态去噪阈值,并随窗格滑动构建去噪阈值向量,由此进行光谱去噪。其中,窗格宽度由相邻区域的噪声方差变化率决定,变化率较高的区域缩小窗格宽度,反之则扩大宽度。实验结果表明,这种去噪算法不仅能有效去除光谱中的非平稳噪声,而且能保留光谱的细节信息,有助于提高仪器的测量精度。与此同时,由于该算法并未使用时域平均,样本的快速变化对去噪性能的影响较小,适合在线或原位水质检测的水样本环境。     

铁磁材料动态磁滞回线测绘方法的优化设计

文中介绍一种涉及铁磁材料动态磁滞回线测绘方法的优化设计.该设计能观察和测绘硬、软磁样品的动态磁滞回线,观察、测绘速度快,方法简便,检测有关数据较准确.     

Practical aspects for SQUID applications

Classical applications of superconducting quantum interference devices (SQUIDs), like biomagnetic measurements or precision voltage and current measurements have in almost all cases been carried out in a magnetically and electrically well shielded environment. Recently, the demonstration of highly sensitive HTS SQUIDs has increased the interest in SQUIDs for a broader range of applications like geophysical measurements or nondestructive materials evaluation. The operation of SQUIDs in an unshielded environment, however, leads in many cases to a significant reduction in their sensitivity due to numerous sources of interference and excess noise. The paper reviews recent work on aspects related to the operation of SQUIDs in unshielded environments.     

Simultaneous determination of tofacitinib and its principal metabolite in beagle dog plasma by UPLC-MS/MS and its application in pharmacokinetics

The main objective of our current study is to develop and validate an accurate and direct ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method to simultaneously detect plasma concentrations of tofacitinib and its metabolite M9, and to study the pharmacokinetic profiles of the two compounds in beagle dogs. After rapid precipitation of protein by adding acetonitrile, the chromatographic separation of tofacitinib was completed, as well as M9 and upadacitinib (internal standard, IS) by using an Acquity BEH C18 (1.7 μm, 2.1 mm × 50 mm) column. A Xevo TQ-S triple quadrupole tandem mass spectrometer was employed to determine their concentrations under the positive ion pattern. Selective reaction monitoring (SRM) was used with ion transitions at m/z 313.12 → 148.97 for tofacitinib, m/z 329.10 → 137.03 for M9, and m/z 380.95 → 255.97 for IS, respectively. This assay demonstrated excellent linearity, and the ranges of calibration curves for both tofacitinib and M9 were 0.5–400 ng/mL. The new UPLC-MS/MS assay can reach the values (0.5 ng/mL) of lower limit of quantification (LLOQ) for both tofacitinib and M9. Both intra-day and inter-day accuracy of all analytes ranged from ?12.0% to 14.3%, while the precision was ≤13.2%. The recovery rate of all analytes was >88.5%, and more importantly there was no conspicuous matrix effect. In addition, the stability was consistent with the quantificative requirements of plasma samples under all conditions. Finally, the assay on UPLC-MS/MS is able to be employed to determine the pharmacokinetic characteristics of tofacitinib and its metabolite M9 in the plasma of beagle dogs after taking orally a dose of tofacitinib at 2 mg/kg.     

微波辅助萃取/样品前处理联用技术的研究进展

微波辅助萃取是近年来新发展的一种样品前处理技术,随着微波辅助萃取的发展和成熟,它与其它样品前处理技术的联用得到了迅速发展。与传统前处理方法相比,这些联用方法具有快速、高效、操作简便、节省溶剂、选择性好、应用范围广的特点。该文综述了微波辅助萃取及其与其它样品前处理技术联用的特点及适用性,并对近年来微波辅助萃取与其它前处理方法联用的发展概况及在分析领域中的应用情况进行了详细总结。     

蓝色圆珠笔字迹的高效液相色谱分析与模式识别研究

该文收集市售蓝色圆珠笔样品16份,结合模式识别技术对其高效液相色谱数据进行研究。利用相关系数法计算色谱图相对峰面积的相似度,定量地评价样品间的差异性。选取16个样品3个批次间的最小相似度(λ=0.92)作为判定是否源于同种样品的阈值,相似度小于0.92的数据为89份,占全部比对样品的74.2%;根据液相色谱图的保留时间、峰数及峰形差异将所有样品分为3类,进一步利用系统聚类法依据相似度的大小将第一类样品分为3小类。该文提出的采用相对峰面积相似度评价样品差异的方法,能够显著提高分辨能力,促进圆珠笔字迹的自动化识别。高效液相色谱法获取数据,模式识别技术分析数据的方法为圆珠笔字迹的分类与鉴别提供了新思路。