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991.
Kaikai Li Xianggang Shi Xiaorong Yang Yuanyuan Wang Chuangxing Ye Zhongyi Yang 《International Journal of Food Science & Technology》2012,47(5):1063-1071
Two kinds of green tea were prepared with the young shoots of Camellia kucha and C. ptilophylla, and antioxidative activities of the chemical constituents were determined. Levels of alkaloids, catechins, total polyphenols, flavonoids and amino acids were determined by high‐performance liquid chromatography and UV‐Vis spectrophotometer. Antioxidative activity was evaluated by applying 2,2‐diphenyl‐1‐picrylhydrazyl radical assay and ferric reducing antioxidant power assay. Our results showed that theobromine was the only alkaloid in C. ptilophylla, while there was theacrine in C. kucha, which was coexisting with the caffeine. We confirmed the high content of (?)‐gallocatechin gallate in C. ptilophylla was not the epimerisation of (?)‐epigallocatechin gallate during the heating procedure. These wild teas had higher content of tea polyphenols, water extracts, amion acids and stronger antioxidative activity compared with the longjing tea. They could be used for the development of noncaffeine beverages and new types of tea. 相似文献
992.
Carbon nanotube/Co<Subscript>3</Subscript>O<Subscript>4</Subscript> composite for air electrode of lithium-air battery 总被引:1,自引:0,他引:1
A carbon nanotube [CNT]/Co3O4 composite is introduced as a catalyst for the air electrode of lithium-air [Li/air] batteries. Co3O4 nanoparticles are successfully attached to the sidewall of the CNT by a hydrothermal method. A high discharge capacity and
a low overvoltage indicate that the CNT/Co3O4 composite is a very promising catalyst for the air electrode of Li/air batteries. 相似文献
993.
介绍了天然气重整制氢新技术,包括选择性透氢膜,选择性透氧膜,化学循环以及CO2吸收的研究进展,介绍了4种新技术应用于制氢装置中的概念设计,并比较了4种技术的优缺点。 相似文献
994.
Gamal ElMasry Noha Morsy Salim Al-Rejaie Charfedinne Ayed Robert Linforth Ian Fisk 《International Journal of Food Science & Technology》2019,54(11):2983-2997
The aim of this study was to use gas chromatography-mass spectrometry (GC-MS) and APCI-MS techniques to detect adulteration in honey. The key volatile compounds in the headspace of the adulterated honey were marked by GC-MS and their representative fragment ions were utilised in scanning honey samples using the real-time APCI-MS system. The PLS models validated using independent data sets resulted in coefficient of the determination () of 0.97 and 0.96 and root mean square error in prediction (RMSEP) of 2.62 and 2.45 for the GC-MS and APCI-MS data sets respectively. The most efficient volatiles from GC-MS analysis and their corresponding fragment ions m/z from APCI-MS data analysis were then identified and used to develop new PLS models to predict the level of adulteration. The best PLS model gave of 0.95 and RMEP of 2.60% in the independent validation set indicating that the model was very accurate in predicting the level of adulteration. 相似文献
995.
Rui B. Ferreira D.S. Falcão A.M.F.R. Pinto 《International Journal of Hydrogen Energy》2021,46(1):1106-1120
Membrane chemical degradation is a major contributor to the still limited lifetime of proton exchange membrane (PEM) fuel cells. In the present work, this phenomenon is simulated by computational fluid dynamics (CFD). The main advantage of the CFD model is that it can provide the degradation profile across the cell active area. Results reveal that degradation accelerates when voltage, temperature and pressure are increased and when reactants humidity and membrane thickness are decreased. Moreover, membrane deterioration is found to be more severe where oxygen pressure is higher, and more heterogeneous when oxygen distribution is less uniform. Generally, conditions that increase current production and thus oxygen depletion along the cell increase degradation heterogeneity. The flow field design is also found to influence the membrane degradation spatial profile. The modeling strategy here applied, the incorporation of a degradation sub-model into a general-purpose CFD code, can be used to include other degradation mechanisms. 相似文献
996.
Chemical chain combustion technology is a new combustion technology that achieves efficient and low energy separation for CO2 capture. CaSO4- Fe2O3 oxygen carrier was prepared by sol- gel method from blast furnace slag containing iron, and X- ray diffraction (XRD) and scanning electron microscopy and energy dispersive X- ray (SEM- EDX) were used to characterize the oxygen carrier particles. The results show that the CaSO4- Fe2O3 oxygen carrier prepared from iron metallurgical dust has a mass fraction of 93. 58%, a specific surface area of 10. 37cm2/g and a conversion rate of 67. 47% after reaction?? with coal powder, which has good reactivity. Combined with SEM and EDS analysis, the main cause of the decrease of carrier activity is the accumulation of coal ash during the cycle combustion process, resulting in complex and diversified carrier components, chemical reactions and agglomeration effects, and then carrier activity is reduced. 相似文献
997.
Ambrish Kumar Srivastava Anoop Kumar Pandey Saurabh Pandey 《Polycyclic Aromatic Compounds》2016,36(4):452-466
In this article, we made a comparative study of two multiple myeloma drugs: lenalidomide and pomalidomide. We calculated and discussed their geometries at DFT/B3LYP method. Intra-molecular hydrogen bonding in these molecules is confirmed and characterized by QTAIM calculations. Electronic parameters along with HOMO-LUMO and MESP surfaces are calculated in order to compare their chemical reactivity. The effect of structure and bonding on electronic properties and biological activities is discussed and it is established that pomalidomide is more biologically active than lenalidomide. The phenyl ring of these molecules show teratogenic effects, making a possibility of finding another new class of drugs. 相似文献
998.
999.
Pei Zhao Qiong Zhang Wei Wu Takashi Goto Junxia Yu 《Journal of the American Ceramic Society》2019,102(4):2135-2142
SrTiO3 (STO) film was prepared on quartz glass by laser chemical vapor deposition at a deposition temperature (Tdep) ranged from 760 to 1104 K. Effect of the Tdep on the orientation, crystallinity, texture, and microstructure of the STO film was investigated. As the Tdep was increased, the preferred orientation of the STO film tended to be (110)-orientated with corresponding texture coefficient (TC) on the (110) reflection enhanced from 2.3 to 6; meanwhile, the full width at half maximum of the ω-scan on the (110) reflection decreased from 0.85° to 0.59°. The (110)-oriented grains were in wedge shape about 60 × 150 nm in size, which tended to be flat at an elevated Tdep of 1104 K. 相似文献
1000.
《Ceramics International》2021,47(23):33047-33056
In this paper, two kinds of composites constructed by UO3 nanoflakes (which is UO3·yNH3·xH2O, precisely) and different graphene oxide (GO) nanosheets (homemade GO, GO-h, and commercial GO, GO-c) were prepared via solution chemical reaction. The two kinds of GO share similar morphology and possess the same species of functional groups. Nevertheless, GO-h possesses higher oxidization degree and thus could adsorb more uranyl ions, and the corresponding composite shows a much more regular shape: UO3 nanoflakes and GO nanosheets cross each other, which would help overcome the disadvantage of graphene aggregation. As a result, homemade reduced graphene oxide (RGO-h) sheets inside the final UO2 pellets (named as UO2/GO-h) could construct a well-bulit thermally conductive network to enhance its thermal conductivity. However, similar RGO-c network cannot be observed in the UO2/GO-c pellest originated from GO-c. Therefore, only the thermal conductivity of UO2/GO-h pellet acquires a dramatic increase, 37.30% relative to UO2 pellet at 1200 °C, showing that UO2/GO-h possesses great potential for the development of novel UO2-based ATF fuels. 相似文献