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21.
The nonlinear stochastic evolution equations have a wide range of applications in physics, chemistry, biology, economics and finance from various points of view. In this paper, the $\left({G^{\prime}}/{G}\right)$ -expansion method is implemented for obtaining new travelling wave solutions of the nonlinear (2?+?1)-dimensional stochastic Broer–Kaup equation and stochastic coupled Korteweg–de Vries (KdV) equation. The study highlights the significant features of the method employed and its capability of handling nonlinear stochastic problems. 相似文献
22.
Low-frequency (2.72-3.70 Hz) relaxation oscillations at 100 mTorr at higher absorbed power were observed from time-varying optical emission of the main discharge chamber and the periphery. We interpret the low frequency oscillations using an electromagnetic model of the slot impedance with parallel connection variational peripheral capacitance, coupled to a circuit analysis of the system including the matching network. The model results are in general agreement with the experimental observations, and indicate a variety of behaviours dependent on the matching conditions. 相似文献
23.
Thermal analysis has been integrated into our physical chemistry laboratory course in order to allow students to systematically explore the role of composition in determining the physical properties of a binary mixture. The -naphthol/acetamide system is presented as an interesting starting point for such a project, as it displays a temperature/composition phase diagram which deviates slightly from the simple two-component eutectic picture. Students compare their measured pure-component melting temperatures with literature values, rationalize the observed trends with mixing using freezing-point-depression arguments, and make a literature search of the unique morphological solid phase obseved in analogous studies. This hands-on project is designed to be accompanied by a classroom discussion of multicomponent phase equilibria. 相似文献
24.
Nonlinear stochastic partial differential equations have a wide range of applications in science and engineering. Finding exact solutions of the Wick-type stochastic equation will be helpful in the theories and numerical studies of such equations. In this paper, Kudrayshov method together with Hermite transform is implemented to obtain exact solutions of Wick-type stochastic Korteweg–de Vries equation. Further, graphical illustrations in two- and three-dimensional plots of the obtained solutions depending on time and space are also given with white noise functionals. 相似文献
25.
超高效液相色谱-串联质谱法同时测定土壤中239种农药的残留量 总被引:2,自引:0,他引:2
建立了超高效液相色谱-串联质谱法(UPLC-MS/MS),可于10 min内快速测定土壤中的239种农药残留。土壤样品经AOAC (Association of Official Analytical Chemists) QuEChERS方法处理,用乙腈萃取;无水硫酸镁、乙酸钠固液分离后,过0.2 μm滤膜;在UPLC-MS/MS正、负离子同步扫描多反应监测模式下进行分析。239种农药中,线性相关系数(r2)大于0.99的有236个,占总数的99%。在40 μg/kg添加水平下所有被检测农药的回收率均在50%~150%之间,且相对标准偏差(RSD)均小于20%;其中有209种农药的回收率达到70%~120%,有161种的RSD小于10%。方法的检出限(LOD)范围为0.69~29.04 μg/kg。土壤中多种农药残留的同时检测要求时间短、准确度和精密度高,本方法符合这些检测要求,适用于土壤中农药残留的检测。 相似文献
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KIM Mi-Ran SUH Bo-Ram KIM Jae-Gil KIM Young-Ho KIM Dae-Keun MOON Dong-Cheul 《高等学校化学学报》1999,20(Z1):190
Carpesium triste var. manshuricum K. is a plant which is rarely distributed in Korea, and it has long been used as traditional medicinal herb for its antipyretic, analgesic, vermifugic, insectifuge,pain-relief,and antiinflammatory properties. Several sesquiterpene lactones were isolated from the genus Carpesium. 相似文献
29.
A pentaammineazidocobalt(III) complex, [Co(NH3)5N3](MnO4)2XH2O has been synthesized by an one-pot synthesis method. It was characterized by studies such as infrared (IR) and UV-visible spectroscopy. The single crystal X-ray structure analysis revealed that the title complex crystallizes in space group Cc. The cobalt center is six coordinated with slightly octahedral geometry. The supramolecular architecture is also formed by intermolecular N-H…O (anion and H2O) and Mn-O…O-H hydrogen bonds. The binding property of the cation, [Co(NH3)5N3]2+ with the anion, MnO4– has also been determined (in solution phase) with the help of UV-visible spectroscopic titrations. Further, the genotoxic effects of KMnO4, [Co(NH3)5N3]Cl2 and [Co(NH3)5N3](MnO4)2XH2O were studied using Allium cepa root chromosomal aberration assay and it revealed that the genotoxicity of the newly synthesized complex is 1.97–1.76 fold, which is less compared to KMnO4. The order of genotoxic potential has been observed to be KMnO4 > [Co(NH3)5N3](MnO4)2XH2O > [Co(NH3)5N3]Cl2. 相似文献
30.
Sukkum Ngullie CHANG Jeong Jun LEE Hyun Jin KIM Sun Chul KANG 《Turkish Journal of Chemistry》2021,45(4):1155
Vitamin D2 (vit. D2) is a nutraceutical essentially needed for good health. However, it is susceptible to oxygen and high temperature. The use of natural products such as bioflavonoids possessing anti-degradative effect of vit. D2 degradation has not been described before. A combinational effect of vit. D2 with quercetin showed a positive effect and inhibited vit. D2 degradation when exposed to high temperature (50 ℃ and 75 ℃) at different time points. The results obtained revealed vit. D2 degradation was drastically increased with longer incubation under thermal treatment. However, quercetin and vit. D2 groups were able to significantly inhibit the degradation of vit. D2 and stabilize it, evaluated through the retention percentage. We also exposed vit. D2 at solutions with different pH values (1, 4, 5, 7, 10). Quercetin exerted vit. D2 anti-degradation at different pH values as well as under thermal pressure at different time points. Conclusively, quercetin can be an effective way to reduce temperature and pH induced degradation of vit. D2. 相似文献