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231.
The synthesis of parapyruvate is important for the analysis of the content in the pyruvate supplements and the study of aging-related neurodegenerative diseases. However, the pure parapyruvate crystal is not, as yet, commercially available. In this study, we applied the Taguchi’s L9 orthogonal array to investigate the optimal conditions for the preparation of the pure parapyruvate by the alkaline treatment of the pyruvic acid and then followed it with the solvent crystallization steps. We were also interested in revealing the major factors that affect the yield for the synthesized pure parapyruvate crystals. In addition, the parapyruvate-inhibited enzyme kinetic of α-ketoglutarate dehydrogenase complex (KGDHC) was also investigated. We found that the pure parapyruvate could be obtained in combination with an alkaline treatment and two solvent crystallization steps. The main factors affecting the yield of the pure parapyruvate were the concentration of the pyruvic acid (the reactant), the pH of the alkali treatment, the type of solvent used for the crystallization and the volume ratio of solvent used for crystallization. Finally, the optimal conditions could prepare parapyruvate crystals with a high purity of 99.8% and a high yield of 72.8%. In addition, the results demonstrate that parapyruvate is a reversibly competitive inhibitor for KGDHC. 相似文献
232.
A new model of particle yield stress including cohesive strength is proposed, which considers the friction and cohesive strength between particles. A calculation method for the fluidization process of liquid–solid two-phase flow in compact packing state is given, and the simulation and experimental studies of fluidization process are carried out by taking the sand–water two-phase flow in the jet dredging system as an example, and the calculation method is verified. 相似文献
233.
234.
Shitong Cui Yanfen Wu Yao Liu Qingwen Guan Yida Zhang Yilin Zhang Song Luo Meng Xu Juncheng Wang 《中国化学快报》2020,31(2):487-493
Carbon dots(CDs) with multi-color emissive properties and a high photoluminescent quantum yield(PLQY) have attracted great attention recently due to their potential applications in chemical,environmental,biological and photo-electronic fields.Solvent-dependent effect in photoluminescence provides a facial and effective approach to tune the emission of CDs.In this study,green emissive nitrogen-doped carbon dots(N-CDs) are synthesized from p-hydroquinone and ethylenediamine through a simple hydrothermal method.The as-prepared N-CDs possess a robust excitation-independent green luminescence and a high PLQY of up to 15.9%.Further spectroscopic characterization indicates that the high PLQY is achieved by the balance of nitrogen doping states and the surface passivation extent in CDs.The N-CDs also exhibit solvent-dependent multi-color emissive property and distinct PLQY in different solvents(the maximum can reach up to 25.3%).Furthermore,the as-prepared N-CDs are applied as fluorescence probes to detect acetone and H2O2 in water.This method has exhibited a low detection limit of acetone(less than 0.1 %) and a quick and linear response to the H_2O_2 with the concentration from 0 to 120 μmol/L.This work broadens the knowledge of applying CDs as probes in the bio and chemical sensing fields. 相似文献
235.
Dr. Shun Nishimura Dr. Junya Ohyama Takaaki Kinoshita Son Dinh Le Dr. Keisuke Takahashi 《ChemCatChem》2020,12(23):5836-5836
236.
237.
H.M. Mahmudov M.K. Ismayilova S.A. Hasanova S.M. Aliyev G.E. Isayeva O.E. Akberov 《辐射效应与固体损伤》2016,171(7-8):630-635
The aim of this study was to investigate the regularities of molecular hydrogen formation from water dispersing Al2O3 nanoparticles irradiated with gamma ray. It was established that formed molecular hydrogen’s yield changed depending on the size of the catalyst, so that yield of molecular hydrogen formed on the surface with small size is 1.4–1.6 times greater than the one with big size. Equal distribution of nanocatalyst in water medium and much more adsorption of water molecule on the catalyst surface result in more efficient radiolysis process. 相似文献
238.
Rimma Lapovok Emil Zolotoyabko Alex Berner Yaron Kauffmann Eugene Lakin Natalya Larianovsky 《哲学杂志》2016,96(11):1022-1046
An effect of alloying element content on mechanical properties and precipitate formation in Mg–RE alloys was studied for Mg–8Gd–4Y–1Zn–0.4Zr (wt%) and Mg–10Gd–5Y–1.8Zn–0.4Zr (wt%). It is shown that small variations in the alloying element concentration can be used to manipulate the alloy microstructure and precipitate formation towards eliminating the asymmetry (tension/compression) and anisotropy of yield stress. 相似文献
239.
Pei-Xian Li Meng-Yun Guan Chang-Gen Yang Peng Zhang Jin-Chang Liu Yong-Peng Zhang Cong Guo Yi Wang 《中国物理C(英文版)》2016,40(11):116005-116005
Liquid argon (LAr) is an attractive target for the direct detection of WIMPs. A LAr prototype detector was designed to study the technology and properties of LAr detectors. The prototype detector had an active volume containing 0.65 kg of liquid argon. A liquid nitrogen (LN) cooling system allowed the temperature fluctuation of the liquid argon to be controlled within less than 0.1 K during a one month run. In the 22Na calibration run, the LAr prototype obtained 1.59±0.02 p.e./keV light yield for 511 keV gamma rays using a domestic-made argon purification system. 相似文献
240.
For modern and future circular accelerators, especially high-intensity proton synchrotrons or colliders, the electron cloud effect is a key issue. So, in order to reduce the electron cloud effect, exploring very low secondary electron yield (SEY) material or coating used in vacuum tubes becomes necessary. In this article, we studied the SEY characteristics of graphene films with different thicknesses which were deposited on copper substrates using chemical vapor deposition. The SEY tests were done at temperatures of 25℃ and vacuum pressure of (2-6)×10-9 torr. The properties of the deposited graphene films were investigated by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The SEY curves show that the number of graphene layers has a great effect on the SEY of graphene films. The maximum SEY of graphene films decreases with the increase of the number of layers. The maximum SEY of 6-8 layers of graphene film is 1.25. These results have a great significance for next-generation particle accelerators. 相似文献