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51.
Yue Wang Jing Feng Song Wu Huihui Shao Wenxuan Zhang Kun Zhang Hanyilan Zhang Qingyun Yang 《Molecules (Basel, Switzerland)》2022,27(6)
A new derivatization high-performance liquid chromatography method with ultraviolet detection was developed and validated for the quantitative analysis of methanesulfonate genotoxic impurities in an innovative drug for the treatment of non-alcoholic fatty liver disease. In this study, sodium dibenzyldithiocarbamate was used as a derivatization reagent for the first time to enhance the sensitivity of the analysis, and NaOH aqueous solution was chosen as a pH regulator to avoid the interference of the drug matrix. Several key experimental parameters of the derivatization reaction were investigated and optimized. In addition, specificity, linearity, precision, stability, and accuracy were validated. The determined results of the samples were consistent with those obtained from the derivatization gas chromatography–mass spectrometry analysis. Thus, the proposed method is a reliable and practical protocol for the determination of trace methanesulfonate genotoxic impurities in drugs containing mesylate groups. 相似文献
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Shaolei Yang Chunyan Chen Zhihong Yan Qingyun Cai Shouzhuo Yao 《Journal of separation science》2013,36(7):1283-1290
Metal‐organic frameworks, a new class of materials with high surface area and great porosity, have been widely applied in gas sorption. It is generally known that metal‐organic framework 5 cannot be applied in aqueous phase since it is water sensitive. However, this work reveals that the derived material of metal‐organic framework 5 is a good SPE sorbent that can be applied to aqueous phases. Metal‐organic framework 5 was prepared and used as a SPE sorbent for the determination of polycyclic aromatic hydrocarbons in environmental matrices coupling with HPLC. The water treatment induced changes in the properties were investigated in detail. Even though metal‐organic framework 5 is conversed to a second phase after water treatment, it still shows high extraction ability. Under the optimized experimental conditions, good sensitivity levels were achieved with low LODs ranging from 0.4 to 4.0 ng L?1 and a linearity of 0.004–20 μg L?1 (R2 > 0.996) for the investigated polycyclic aromatic hydrocarbons. The method has been validated in the analysis of real water samples with recoveries in the range of 80.2–120.2% and RSDs in the range of 0.5–11.7%. 相似文献
54.
This paper proposes a novel secure communication scheme based on the Karhunen–Loéve decomposition and the synchronization of a master and a slave hyperchaotic Lü systems. First, the Karhunen–Loéve decomposition is used as a data reduction tool to generate data coefficients and eigenfunctions that capture the essence of grayscale and color images in an optimal manner. It is noted that the original images can be reproduced using only the most energetic eigenfunctions; this results in computational savings. The data coefficients are encrypted and transmitted using a master hyperchaotic Lü system. These coefficients are then recovered at the receiver end using a sliding mode controller to synchronize two hyperchaotic Lü systems. Simulation results are presented to illustrate the ability of the proposed control law to synchronize the master and slave hyperchaotic Lü systems. Moreover, the original images are recovered by using the decrypted data coefficients in conjunction with the eigenfunctions of the image. Computer simulation results are provided to show the excellent performance of the proposed scheme. 相似文献
55.
针对准脆性材料的非线性特征,在热动力学框架内,建立了准脆性材料的弹塑性与各向异性损伤耦合的本构关系.对准脆性材料的变形机理和损伤诱发的各向异性进行了诠释,并给出了损伤构形和有效构形中各物理量之间的关系.在有效应力空间内,建立了塑性屈服准则、拉压不同的塑性随动强化法则和各向同性强化法则.在损伤构形中,采用应变能释放率,建立了拉压损伤准则、拉压不同的损伤随动强化法则和各向同性强化法则.基于塑性屈服准则和损伤准则,构建了塑性势泛函和损伤势泛函,并由正交性法则,给出了塑性和损伤强化效应内变量的演化规律,同时,联立塑性屈服面和损伤加载面,给出了塑性流动和损伤演化内变量的演化法则.将损伤力学和塑性力学结合起来,建立了应变驱动的应力-应变增量本构关系,给出了本构数值积分的要点.以单轴加载-卸载往复试验识别和校准了材料常数,并对简单试验进行了预测,结果表明,所建本构模型对准脆件材料的非线性材料性能有良好的预测能力. 相似文献
56.
Yutang Liu Xilin Zhang Ronghua Liu Chengbin Liu Qingyun Cai 《Journal of solid state chemistry》2011,184(3):684-689
A new ZnTe modified TiO2 nanotube (NT) array catalyst was prepared by pulse potential electrodeposition of ZnTe nanoparticles (NPs) onto TiO2 NT arrays, and its application for photocatalytic degradation of anthracene-9-carboxylic acid (9-AnCOOH) was investigated. The even distribution of ZnTe NPs was well-proportionately grown on the top surface of the TiO2 NT while without clogging the tube entrances. Compared with the unmodified TiO2 NT, the ZnTe modified TiO2 NT (ZnTe/TiO2 NT) showed significantly enhanced photocatalytic activity towards 9-AnCOOH under simulated solar light. After 70 min of irradiation, 9-AnCOOH was degraded with the removal ratio of 45% on the bare TiO2 NT, much lower than 80%, 90%, and 100% on the ZnTe/TiO2 NT with the ZnTe NPs prepared under the pulsed “on” potentials of −0.8, −1.0, and −2.0 V, respectively. The increased photodegradation efficiency mainly results from the improved photocurrent density as results of enhanced visible-light absorption and decreased hole-electron recombination due to the presence of narrow-band-gap p-type semiconductor ZnTe. 相似文献
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58.
为了得到场约束方式下,金属陶瓷封装端窗透射微型X光管发射电流的最大化和焦斑尺寸的最小化,对热阴极发射体的几何结构进行仿真计算,为设计实物模型提供技术方案。首先,从理论上推导了直热式阴极发射体、发射电流密度与几何结构的关系,其次讨论了有限积分算法在求解电场分布数值解过程中的离散化思路,最后利用CST粒子工作室软件,建立了几何模型,对阴极发射体的几何结构进行了优化。在灯丝距离控制极0.4 mm、控制极开孔直径为0.6 mm的位置,能够得到较小的焦斑和较高的电荷密度分布。试制的阴极发射体最大发射电流可达85 A。 相似文献
59.
Qingyun Chang Tao Feng Shuangju Song Xin Zhou Chun Wang Zhi Wang 《Mikrochimica acta》2010,171(3-4):241-247
A novel method was developed for the determination of eight pyrethroids in water samples by liquid–liquid microextraction based on solidification of floating organic droplets followed by gas chromatography with electron capture detection. The type and volume of the extraction solvents, extraction time, sample solution temperature, stirring rate and ionic strength were studied and optimized. Under the optimum conditions, enrichment factors ranged from 824 to 1,432, and the limit of detection range from 2.0 to 50 ng?L?1. The calibration graph is linear from 0.15 to 80 μg?L?1 for cyfluthrin, fenvalerate, fluvalinate and deltamethrin, 0.09 to 80 μg?L?1 for fenpropathrin, 0.006 to 80 μg?L?1 for lambda-cyhalothrin, 0.026 to 80 μg?L?1 for permethrin, 0.01 to 80 μg?L?1 for cypermethrin. The correlation coefficients (r) varied from 0.9961 to 0.9988. The method was successfully applied to the determination of pyrethroid pesticide residues in tap water, well water, reservoir water, and river water. Recoveries ranged from 79.0% to 113.6%, and relative standard deviations are between 4.1% and 8.7%. 相似文献
60.
Nonlinear Dynamics - Motivated by the recent experimental findings that thalamic reticular nucleus (TRN) may be a pacemaker of absence seizures, we explore whether changes in the level of TRN... 相似文献