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针对无机化学传统教学模式的不足,构建了无机化学微信平台。介绍了构建平台必需的微信公众号和微信群的建立过程和方法。分析了无机化学微信平台在教学中的实践效果,弥补了传统教学中的不足。讨论了无机化学微信平台的积极作用,提高了教师教学水平和学生的学习能力,达到了师生双赢的目的。 相似文献
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低维ZnO纳米材料* 总被引:1,自引:0,他引:1
本文主要综述了近年来ZnO纳米材料制备领域的一些新方法,简单比较了各种方法之间的优缺点;讨论了制备不同形貌的ZnO纳米材料的影响因素,其中重点讨论了表面活性剂的作用;介绍了ZnO纳米材料的性质及其可能的应用领域;并对ZnO纳米材料的发展前景进行了展望。 相似文献
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随着纳米技术的发展以及Pickering乳液在食品、化妆品、医药等领域的潜在应用前景,人们对Pickering乳液给予了关注。本文全面总结了近些年来Pickering乳液的研究进展,对本课题组在Pickering乳液研究领域所取得的成果进行了介绍。本文主要分为4个部分:第一部分概述了Pickering乳液的研究现状;第二部分全面考察了Pickering乳液的各种影响因素;第三部分介绍了Pickering乳液的转相特性;最后综述了颗粒和表面活性物质协同稳定乳液的研究进展。这些研究成果促进了乳液基础理论的发展,并且拓展了乳液的应用范围。 相似文献
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A method is presented for the efficient computation of the representation matrices of the unitary group, U(n) in the Gelfand—Tsetlin basis (corresponding to the usual spin-symmetry adapted basis for an N electron CI). The present scheme is conceptually and computationally attractive in that it is formulated directly in terms of Weyl tableaux and also that it permits simultaneous basis vector generation and matrix element evaluation. In addition the basis vectors are ordered so that subsequent restriction to the three dimensional rotation group is facilitated. An illustrative example is also presented.Taken in part from a thesis submitted to the University of London in partial fulfilment of the requirements for the degree of PhD. 相似文献
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IntroductionChiralityduetomethylbranchingisabundantamongseveralnaturallyoccuringsecondarymetabolites.Thisstructuralfeatureisparticularlypredominantamonginsectpheromones[1] ,manyofwhichareofeconomicsignificance .Asaconsequence ,aconsiderableefforthasbeenma… 相似文献
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O. Manero J. F. A. Soltero J. E. Puig V. M. González-Romero 《Colloid and polymer science》1997,275(10):979-985
In this work, the linear viscoelastic properties of cetyl-trimethylammonium tosilate–water system are predicted by the modeling
of the relaxation spectrum. The modeled spectrum of relaxation times is of the “wedge-box” type where the “wedge” portion
is located at the short-time scale of relaxation times and the “box” part covers the long-time scale. The linear viscoelastic
properties are calculated through the exact relationships with the suggested spectrum. Agreement between the calculated expressions
and experimental data of the moduli and the stress relaxation function is found. Comparison is also made with predictions
of the empirical expressions of the Cole–Cole and the Williams–Watts models.
Received: 17 December 1996 Accepted: 1 July 1997 相似文献
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Neese F 《Journal of computational chemistry》2003,24(14):1740-1747
A straightforward modification of the resolution of the identity (RI) approximation to the Coulomb interaction is described. In the limit of basis sets that are dominated by high angular momentum functions the observed speedups in realistic test systems reach a factor of 2 compared to the standard RI algorithm, and a factor of up to 300 compared to the standard algorithm to form the Coulomb matrix. More moderate savings on the order of 0-20% are obtained for the more commonly used smaller basis sets. A series of test calculations is reported to illustrate the efficiency of the algorithm. 相似文献
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Samuel Natelson 《Microchemical Journal》1991,44(3)
When glutamic acid is amidinated, guanidinoglutaric acid is formed. This is readily converted by boiling in water to its lactam [2-imino-4-oxo-5-(3′-propane acid) imidazolidine; GGAL]. In the present study GGAL is dehydrated to form a second lactam, anhydro-GGAL (AGGAL), with trifluoroacetic anhydride. The molecular weight of this compound was ascertained gravimetrically by precipitation with flavianic acid and by mass spectrography to be 153.14. UV and infrared spectra and hydrogen and 13C NMR studies determined its structure as an imidazolidine ring fused to a pyrrol ring, 2-imino-4-oxo-imidazolidine-1,5-pyrrolidone-8. On paper electrophoresis, GGAL traveled to the anode, while AGGAL traveled to the cathode. On TLC plates (butanol 60, H2O 25, acetic 15), the Rf value of GGAL was 0.42 and that of AGGAL was 0.38, confirming that AGGAL was more basic than GGAL. The preparation of 1,3-di-(phenylcarbamoyl)-GGAL is also described. 相似文献
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Richiro Ushimaru Zhang Chen Houyuan Zhao Po-hsun Fan Prof. Dr. Hung-wen Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(9):3586-3590
Albomycin δ2 is a sulfur-containing sideromycin natural product that shows potent antibacterial activity against clinically important pathogens. The l -serine-thioheptose dipeptide partial structure, known as SB-217452, has been found to be the active seryl-tRNA synthetase inhibitor component of albomycin δ2. Herein, it is demonstrated that AbmF catalyzes condensation between the 6′-amino-4′-thionucleoside with the d -ribo configuration and seryl-adenylate supplied by the serine adenylation activity of AbmK. Formation of the dipeptide is followed by C3′-epimerization to produce SB-217452 with the d -xylo configuration, which is catalyzed by the radical S-adenosyl-l -methionine enzyme AbmJ. Gene deletion suggests that AbmC is involved in peptide assembly linking SB-217452 with the siderophore moiety. This study establishes how the albomycin biosynthetic machinery generates its antimicrobial component SB-217452. 相似文献
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J. van Brakel 《Foundations of Chemistry》1999,1(2):111-174
In this paper I present a historiography of the recent emergence of philosophy of chemistry. Special attention is given to the interest in this domain in Eastern Europe before the collapse of the USSR. It is shown that the initial neglect of the philosophy of chemistry is due to the unanimous view in philosophy and philosophy of science that only physics is a proper science (to put in Kant's words). More recently, due to the common though incorrect assumption that chemistry can in principle be reduced to physics, the neglect continued, even when interest in sciences such as biology and psychology entered more strongly in philosophy of science. It is concluded that chemistry is an autonomous science and is perhaps a more typical science than physics. 相似文献
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T. Tahri S. A. Abdul-Wahab A. Bettahar M. Douani H. Al-Hinai Y. Al-Mulla 《Journal of Thermal Analysis and Calorimetry》2009,96(1):35-42
A theoretical model is developed in Part I of this study to simulate the physical process of condensation of the humid air
in the condenser of an existing seawater greenhouse that is located in Muscat, Oman. Application is conducted in this part
to validate the theoretical developments. Comparisons are made between the predictions and the existing experimental results.
The results indicate that the comparison is well consistent. The effect of the relative humidity, the dry bulb temperature
and the solar radiation are also discussed to see their effects on the condensate values. 相似文献
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Litjens RE den Heeten R Timmer MS Overkleeft HS van der Marel GA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(3):1010-1016
The first synthesis of the trisaccharide repeating unit of the acidic polysaccharide of the bacteriolytic complex of lysoamidase is presented. The construction is based on a linear glycosylation strategy that starts from the reducing end and employs thio- and selenoglycosides in a highly stereoselective manner by a single set of activation conditions. The thus-formed trisaccharide is selectively deprotected and oxidised, after which a final deprotection step furnishes the desired repeating unit. 相似文献
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[reaction: see text]. A synthesis of a reduced version of the naphthazarin found in the rubromycin class of natural products is reported. The naphthalene ring system is formed via a D?tz reaction with a symmetrical alkyne. Differentiation between the C1' and C3' groups of the D?tz adduct is achieved by selective oxidation since the two methylene groups possess different oxidation potentials. 相似文献