Coenzyme Q10 and vitamin E are among the most widely consumed nutritional supplements in China owing to their antioxidant and other health-promoting properties.This study aimed to establish an accurate and efficient a...Coenzyme Q10 and vitamin E are among the most widely consumed nutritional supplements in China owing to their antioxidant and other health-promoting properties.This study aimed to establish an accurate and efficient analytical method for the simultaneous determination of these two compounds in commercial softgel capsules,which is essential for rigorous quality control.Herein,a proton nuclear magnetic resonance(1H NMR)method was developed and validated using coumarin as an internal standard.Characteristic signals at 3.997 ppm for coenzyme Q10 and 2.621 ppm for vitamin E were selected for quantification.The method demonstrated excellent performance in terms of precision(relative standard deviation<2%),specificity(resolution>1.5),and stability(24-h variation<3%).The validation results complied with the China Food and Drug Administration guidelines,demonstrating high accuracy.Application to products from four different manufacturers showed compound contents ranging from 98.2%to 102.4%of label amounts.These findings support^(1)H NMR spectroscopy as a rapid,precise,and reliable approach for the simultaneous quality assessment of coenzyme Q10 and vitamin E formulations.展开更多
淬火-分配(Quenching and partitioning,Q&P)钢是淬火和分配复合作用的结果,淬火得到高强度马氏体基体,分配稳定残留奥氏体提高塑性。本工作通过采用具有不同冷速的淬火介质———油、13%PAG和HX-2000淬火,研究了Q&P工艺中淬火...淬火-分配(Quenching and partitioning,Q&P)钢是淬火和分配复合作用的结果,淬火得到高强度马氏体基体,分配稳定残留奥氏体提高塑性。本工作通过采用具有不同冷速的淬火介质———油、13%PAG和HX-2000淬火,研究了Q&P工艺中淬火冷速对中碳钢组织及性能的影响,并探讨了不同分配温度对碳分配过程的影响。结果表明,淬火快速冷却能得到高碳马氏体组织,有利于促进分配过程中马氏体向残留奥氏体的碳扩散,提高碳分配程度,并且随着淬火冷速的增加,马氏体有效晶粒尺寸减小、马氏体组织细化、位错密度增加,从而使中碳钢得到优异的强度和塑性。高温分配能减弱马氏体和残留奥氏体间的碳不均匀性,促进碳从马氏体向残留奥氏体中扩散,起到稳定残留奥氏体的作用,提高中碳钢的断后伸长率。当采用13%PAG淬火、320℃分配时,中碳钢伸长率为10.34%~10.37%,强塑积能达到18.94~19.21 GPa%,表现出更高的强塑性匹配。展开更多
As more and more variable frequency drives (VFDs), electronic ballasts, battery chargers, and static Var compensators are installed in facilities, the problems related to harmonics are expected to get worse. As a resu...As more and more variable frequency drives (VFDs), electronic ballasts, battery chargers, and static Var compensators are installed in facilities, the problems related to harmonics are expected to get worse. As a result Active power filter (APF) gains much more attention due to excellent harmonic compensation. But still the performance of the active filter seems to be in contradictions with different control strategies. This paper presents detailed analysis to compare and elevate the performance of two control strategies for ex-tracting reference currents of shunt active filters under balanced, un-balanced and non-sinusoidal conditions by using Fuzzy controller. The well known methods, instantaneous real active and reactive power method (p-q) and active and reactive current method (id-iq) are two control methods which are extensively used in active filters. Extensive Simulations are carried out with fuzzy controller for both p-q and Id-Iq methods for different voltage conditions and adequate results were presented. Simulation results validate the superior per-formance of active and reactive current control strategy (id-iq) with fuzzy controller over active and reactive power control strategy (p-q) with fuzzy controller.展开更多
基金supported by the Open Research Fund Program of the Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology(Ocean University of China)。
文摘Coenzyme Q10 and vitamin E are among the most widely consumed nutritional supplements in China owing to their antioxidant and other health-promoting properties.This study aimed to establish an accurate and efficient analytical method for the simultaneous determination of these two compounds in commercial softgel capsules,which is essential for rigorous quality control.Herein,a proton nuclear magnetic resonance(1H NMR)method was developed and validated using coumarin as an internal standard.Characteristic signals at 3.997 ppm for coenzyme Q10 and 2.621 ppm for vitamin E were selected for quantification.The method demonstrated excellent performance in terms of precision(relative standard deviation<2%),specificity(resolution>1.5),and stability(24-h variation<3%).The validation results complied with the China Food and Drug Administration guidelines,demonstrating high accuracy.Application to products from four different manufacturers showed compound contents ranging from 98.2%to 102.4%of label amounts.These findings support^(1)H NMR spectroscopy as a rapid,precise,and reliable approach for the simultaneous quality assessment of coenzyme Q10 and vitamin E formulations.
文摘淬火-分配(Quenching and partitioning,Q&P)钢是淬火和分配复合作用的结果,淬火得到高强度马氏体基体,分配稳定残留奥氏体提高塑性。本工作通过采用具有不同冷速的淬火介质———油、13%PAG和HX-2000淬火,研究了Q&P工艺中淬火冷速对中碳钢组织及性能的影响,并探讨了不同分配温度对碳分配过程的影响。结果表明,淬火快速冷却能得到高碳马氏体组织,有利于促进分配过程中马氏体向残留奥氏体的碳扩散,提高碳分配程度,并且随着淬火冷速的增加,马氏体有效晶粒尺寸减小、马氏体组织细化、位错密度增加,从而使中碳钢得到优异的强度和塑性。高温分配能减弱马氏体和残留奥氏体间的碳不均匀性,促进碳从马氏体向残留奥氏体中扩散,起到稳定残留奥氏体的作用,提高中碳钢的断后伸长率。当采用13%PAG淬火、320℃分配时,中碳钢伸长率为10.34%~10.37%,强塑积能达到18.94~19.21 GPa%,表现出更高的强塑性匹配。
文摘As more and more variable frequency drives (VFDs), electronic ballasts, battery chargers, and static Var compensators are installed in facilities, the problems related to harmonics are expected to get worse. As a result Active power filter (APF) gains much more attention due to excellent harmonic compensation. But still the performance of the active filter seems to be in contradictions with different control strategies. This paper presents detailed analysis to compare and elevate the performance of two control strategies for ex-tracting reference currents of shunt active filters under balanced, un-balanced and non-sinusoidal conditions by using Fuzzy controller. The well known methods, instantaneous real active and reactive power method (p-q) and active and reactive current method (id-iq) are two control methods which are extensively used in active filters. Extensive Simulations are carried out with fuzzy controller for both p-q and Id-Iq methods for different voltage conditions and adequate results were presented. Simulation results validate the superior per-formance of active and reactive current control strategy (id-iq) with fuzzy controller over active and reactive power control strategy (p-q) with fuzzy controller.
