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排序方式: 共有457条查询结果,搜索用时 62 毫秒
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Qiuping Wang Bojan Šarkanj Jasna Jurasovic Yusuf Chisti Michael Sulyok Jiashun Gong Sarote Sirisansaneeyakul Draženka Komes 《International Journal of Food Science & Technology》2019,54(5):1541-1549
Theabrownins (TB) are polymeric phenolic compounds associated with the multiple bioactivities of Pu-erh tea, a post-fermented Chinese dark tea. High-TB instant Pu-erh tea was produced via a novel submerged fermentation (SF) using Aspergillus tubingensis and compared with samples produced commercially via the conventional solid-state fermentation (SSF). Viable microorganisms and microbial toxins, especially aflatoxins B1, G1, B2, G2, cyclopiazonic acid, fumonisins B1, B2, B3 and ochratoxin A, were below the detection limit in all samples. Fewer microbial metabolites were found in SF instant tea compared with the SSF teas. Based on an adult consuming 1 g of instant Pu-erh tea daily, the dietary intake of investigated elements was below the safe limits recommended by various authorities. Tasters viewed the instant tea infusions as very mild, smooth, mellow and full. This suggested that submerged fermentation using A. tubingensis offers a speedy and safe alternative to commercial production of instant Pu-erh tea. 相似文献
3.
R. V. Iyer K. Sooryanarayana T. N. Guru Row K. Vijayan 《Journal of Materials Science》2003,38(1):133-139
Using X-ray diffraction data, the behaviour of Kevlar 49 fibres at low temperatures, up to –100°C, has been analysed. During cooling, the basal plane of the monoclinic unit cell shrinks whereas the c- (unique, chain axis) length is not significantly affected. In contrast, in the return heating cycle to ambient temperature, the basal plane expands and contraction occurs along the chain direction. The unit cell registers a reduction in volume in both the cooling and heating cycles. Conspicuously, after a cycle of cooling and heating, the unit cell does not return to its initial volume. 相似文献
4.
A series of novel thermoplastic elastomers, based on poly(dimethylsiloxane) (PDMS) as the soft segment and poly(butylene terephthalate) (PBT) as the hard segment, were synthesized by catalyzed two‐step, melt transesterification reactions of dimethyl terephthalate and methyl esters of carboxypropyl‐terminated poly(dimethylsiloxane)s (M?n = 550–2170 g mol?1) with 1,4‐butanediol. The lengths of both the hard and soft segments were varied while the weight ratio of the hard to soft segments in the reaction mixture was maintained constant (57/43). The molecular structure, composition and molecular weights of the poly(ester–siloxane)s were examined by 1H NMR spectroscopy. The effectiveness of the incorporation of the methyl‐ester‐terminated poly(dimethylsiloxane)s into the copolymer chains was verified by chloroform extraction. The effect of the segment length on the transition temperatures (Tm and Tg) and the thermal and thermo‐oxidative degradation stability, as well as the degree of crystallinity and hardness properties of the synthesized TPESs, were studied. Copyright © 2003 Society of Chemical Industry 相似文献
5.
Nibedita Mitra Kalyani Vijayan B. N. Pramila Bai S. K. Biswas 《Journal of the American Ceramic Society》1993,76(2):533-535
Cutting of Y2 O3 -doped TZP rods by a low-speed diamond saw introduces an unidentified, metastable phase X (x -ZrO2 ) coexisting with the tetragonal ( t -ZrO2 ) and the monoclinic ( m -ZrO2 ) phases initially present in the sample. Further mechanical deformation of the cut surface by indentation or polishing sustains the x -ZrO2 . Chemical etching removes the x -ZrO2 and increases the m -ZrO2 content. 相似文献
6.
Summary The solution polycondensation of two active diesters, bis(2,4-dinitrophenyl) fumarate and 1,1-(fumaroyldioxy)bis(benzotriazole), with a series of alphatic and aromatic diamines in N-methyl pyrolidone at room temperature, was investigated. The polycondensation reactions yielded a series of fumaric acids polyamides. The polymers obtained from aliphatic diamines were soluble in trifluroacetic acid and exhibited well-defined melting points. The polymers obtained from aromatic diamines are infusible at temperatures below 300°C but were thermally stable and soluble in dimethylacetamide containing 4% LiC1. 相似文献
7.
Ontologies are currently emerging as representation techniques for overlapping compatibility context domains. The continuing need for more effective information retrieval has lead to the creation of the notions of the semantic web and personalized information management. Subsequently, the need for effective ontology visualization for design, management and browsing has arisen. Several ontology visualization tools have come out to strengthen the users’ cognitive support. The primary goal of this paper is to present a survey on recently implemented ontology visualization tools and their contributions in the enrichment of users’ cognitive support. This work also presents the preliminary results of an evaluation of three visualization tools to determine the suitability of each method for end user applications where ontologies are used as browsing aids. 相似文献
8.
Experimental measurements were made of the pH, density, bulk viscosity and electrical conductivity of aqueous solutions of sodium lauryl sulphate for a wide range of concentrations at 25°C. Also, the time-dependent interfacial tension data of this system with mutually saturated benzene phases are reported. Comparison of these data with literature values shows fair agreement in the majority of the cases and further reveals the lack of data in the earlier investigations below the critical micelle concentration of sodium lauryl sulphate in water. A detailed compilation of the data, reported in the literature since 1937, of the pH, density, bulk viscosity, electrical conductivity, surface tension, interfacial tension with benzene, surface excess concentration, surface shear viscosity, diffusivity and critical micelle concentration of the sodium lauryl sulphate system is given. The importance of this anionic surfactant system together with the various factors which influence the physical properties is examined. 相似文献
9.
Pillai S. Vijayan Santhanakrishnan T. Kumar N. Suresh Rajesh R. 《Multidimensional Systems and Signal Processing》2022,33(3):879-898
Multidimensional Systems and Signal Processing - High-performance sonar systems mostly combine a large sensor array and an efficient beamformer for enhancing the overall detection capabilities and... 相似文献
10.
Conducting polypyrrole (PPy) thin-film electrodes were prepared by the electropolymerization of pyrrole on gold-coated glass plates. Films of various roughnesses were obtained by the variation of the scan rates during electropolymerization. These thin films were modified by doping with 6mM of the dopant NiCl2. The surface morphology of the films was studied by scanning electron microscopy and atomic force microscopy (AFM), which suggested films prepared with a high scan rate were rougher in nature than the films produced with a low scan rate. The electrocatalytic reduction of nitrobenzene was carried out with these electrodes with the cyclic voltammetry technique in acetonitrile containing 0.1M HClO4 as a supporting electrolyte. The various results obtained show that the conducting PPy thin-film electrodes were catalytically active toward the electroreduction process. The modified PPy film electrodes doped with NiCl2 were more active toward nitrobenzene electroreduction than the PPy film alone. The results indicate that the roughness of the films played a very important role in determining their catalytic activity. The PPy films that were more rough in nature were catalytically more active than the smooth films; this may have been due to the availability of more reactive sites in the case of rough films. The apparent diffusion coefficients of the PPy film electrodes were also calculated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献