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排序方式: 共有217条查询结果,搜索用时 78 毫秒
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Behzad Haghighi Mohammad Reza Hussaindokht Mohammad Reza Bozorgmehr Naser Seyed Matin 《中国化学快报》2007,18(9):1154-1158
In this paper five equations of state are tested for checking their ability to predict the Joule-Thomson inversion curve.These five equations of state are:Mohsennia-Modarres-Mansoori(MMM),Ji-Lemp(JL),modified Soave-Redlich-Kwang(SRK)equation of state by Graboski(MSRK1),modified SRK equation of state by Peneloux and Rauzy(MSRK2),and modified Peng-Robinson (PR)equation of state by Rauzy(PRmr).The investigated equations of state give good prediction of the low-temperature branch of the inversion curve,except for MMM equation of state.The high-temperature branch and the peak of the inversion curve have been observed,in general,to be sensitive to the applied equation of state.The values of the maximum inversion temperature and maximum inversion pressure are calculated for each component used in this work. 相似文献
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Copolymers of -methyl styrene and 2-ethylhexyl acrylate were prepared in a benzene solution. The presence of the copolymers were confirmed by solubility, IR and NMR tests. The molecular weight and the polydispersity of the polymers were estimated by GPC. The copolymers obtained were blended with paraffinic and naphthenic base oils. The viscosity, the viscosity index (VI) the Q value as well as the stability to shear and oxidation were obtained for these blends. The results are compared with the results obtained with an oil blend containing a commonly used high temperature additive. Two of the copolymers obtained have shown to be good alternatives for specific applications.Presented at the Symposium, 76th CSC Congress, Sherbrooke, Quebec, May 30–June 3, 1993, honoring Professor Donald Patterson on the occasion of his 65th birthday. 相似文献
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The strong affinity of natural ionic polysaccharides for certain metal ions is exploited in the design of a new class of voltammetric sensing devices. In particular, carbon-paste electrodes containing pectic and alginic acids are used for the nonelectrolytic collection and subsequent voltammetric determination of copper and lead, respectively. Cyclic and differential pulse voltammetry are used to quantify the accumulated ions. The response is characterized with respect to modifier loading, preconcentration period, metal concentration, reproducibility, possible interferences and other variables. Titrimetric experiments illustrate the potential of polysaccharide electrodes for speciation work. Preliminary data are also given for analogous measurements of copper at heparin-modified electrodes. Detection limits are 1 mug/ml and the relative standard deviation is 4.8%. 相似文献
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An application of tissue-based electrodes aimed at eliminating interferences from co-existing electroactive constituents is described. The concept is illustrated using a zucchini-containing carbon paste electrode. The presence of the enzyme ascorbic acid oxidase (AAO) in the zucchini tissue effectively eliminates contributions from ascorbic acid, thus allowing selective measurement of dopamine or norepinephrine. In comparison with analogous enzyme-based AAO electrodes, the tissue “eliminator” electrode offers high biocatalytic stability and activity and extremely low cost. The effects of various experimental variables are studied using pulse voltammetry, chronoamperometry and flow-injection amperometry. The electrode has a useful lifetime of 4 weeks. Simultaneous elimination of uric acid interferences is obtained via the co-immobilization of uricase. Oxygen background currents are eliminated in the presence of ascorbic acid. 相似文献
6.
Akbar Mobinikhaledi Naser Foroughifar Tahere Mosleh Ahmad Hamta 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):728-734
Abstract A series of new pyrimidine and quinazoline derivatives was synthesized by a Biginelli-like reaction of urea/thiourea, aldehyde, and ketone in the presence of hydrochloric acid as a catalyst. In a similar way, some novel diazatricyclo derivatives were obtained via a Biginelli-like reaction followed by an intramolecular Michael-type addition. The yields of products were reasonable after recrystallization from ethanol. All newly synthesized compounds were characterized using IR and NMR (1H and 13C) spectroscopy and elemental analysis. The antibacterial activity of these compounds was investigated against Staphylococcus aureus (RTCC, 1885), and Escherichia Coli (ATCC, 35922). Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
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Afradi Nahid Foroughifar Naser Pasdar Hoda Qomi Mahnaz 《Research on Chemical Intermediates》2019,45(5):3251-3271
Research on Chemical Intermediates - Mn0.5Fe0.25Ca0.25Fe2O4@starch@aspartic acid magnetic nanoparticles (MNPs) as a new green nanocatalyst were designed and synthesized by a coprecipitation... 相似文献
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A catalytic multi-component reaction involving aromatic amine,aromatic aldehydes,mercapto acid as substrates and Bi(SCH2COOH)3 as catalyst under solvent free conditions,afforded thiazolidin-4-one in good yields.The efficiency of the catalyst was proved with a variety of substrates,ranging from electrondeficient to electron-rich aldehydes. 相似文献
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A new, one-pot multicomponent reaction of two molecules of aromatic aldehydes with 2,7-naphthalenediol and ammonium hydrogen phosphate is described as an efficient and direct procedure for the preparation of novel 1,3-diphenyl-2-azaphenalene derivatives in a mixture of EtOH-H2O (3:1) under reflux conditions. 相似文献