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1.
《Fluid Phase Equilibria》1986,25(2):137-146
Hajjar, R.F., Cherry, R.H. and Kay, W.B., 1986. Critical properties of the vapor—liquid equilibria of the binary system acetone—n-pentane. Fluid Phase Equilibria, 25: 137–146.The P—V—T—x properties for the acetone—n-pentane azeotrope-forming system have been measured by the technique developed by Kay. The experimental uncertainties have been estimated at 0.05 K, 2.4 kPa and 0.06% of the volume. The results for eight different compositions covering the range 180 to 200°C and 2.5 to 4.0 MPa are given. Smoothed critical loci have been plotted. The critical temperatures and pressures were correlated by a quadratic relationship of the form Qcm = ΣiΣjxixjQcij where i, j = 1, 2. The maximum discrepancy in the critical temperature was 0.6 K and in the critical pressure was 0.012 MPa. 相似文献
2.
The kinetics of the induction period in the polymerization of 1-octene catalyzed by Solvay TiCl3-alkyl aluminium was studied with a dilatometer. The induction period decreases as [TiCl3] and [M]0 increase and temperature rises. It was observed through a microscope that large catalyst particles broke up into small particles in the induction period. So a kinetic model was proposed which ascribes the induction period to the breaking up of catalyst particles under the effect of polymer, and the most of the experimental results can be explained on the basis of the model. 相似文献
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Background
A small heat shock protein AgsA was originally isolated from Salmonella enterica serovar Typhimurium. We previously demonstrated that AgsA was an effective chaperone that could reduce the amount of heat-aggregated proteins in an Escherichia coli rpoH mutant. AgsA appeared to promote survival at lethal temperatures by cooperating with other chaperones in vivo. To investigate the aggregation prevention mechanisms of AgsA, we constructed N- or C-terminal truncated mutants and compared their properties with wild type AgsA. 相似文献6.
《Supramolecular Science》1998,5(5-6):723-731
In the last decade, molecular electronics, as an active frontier of interdisciplinary research areas, has become one of the most rapidly developing fields, and attracted worldwide interests. The fundamental element of molecular electronics is a molecular device or a supramolecular device, which is an organized molecular system constructed mainly by organic molecules or biomolecules that have some specific functions in signal detection, process, storage, and transmission through chemical or physical interactions at molecular or supramolecular levels. A molecular device (MD) can involve chemical information processes, and be relatively easy to realize a large number of links between the molecules. The links can be controlled by the external signals. These are the expected features of molecular computing and directly involve chemical and biological processes. MD may overcome some limitations of the solid-state chips, and can be directly applied to chemical and biological processes. Molecular electronics is a part of bioelectronics. It will play an important and revolutionary role in the next century. This paper intends to review the research activities of molecular electronics in China, particularly in LMBE. 相似文献
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《中国化学快报》2002,13(12):1168-1169
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The Willgerodt-Kindler reaction of acetophenone was studied.Apart from the normal product 4-(benzylthio-carbonyl)morpholine,another product 4-(benzoylthiocarbonyl)morpholine was obtained unexpectedly.The struc-ture of the latter was confirmed by IR,~1H NMR spectra and X-ray diffraction analysis.The mechanism of the reac-tion was discussed. 相似文献
9.
M. F. Reznik D. M. Shub E. V. Kasatkin N. V. Kozlova 《Russian Journal of Electrochemistry》2000,36(8):889-892
Properties and electrocatalytic activity of thin-film (∼2 μm) oxide coatings on aTi support are considered by the example
of the anodic chlorine evolution reaction. The coatings are obtained by thermally decomposing Co and Sn chloride solutions
of different compositions on a Ti plate. The Co and Sn oxides are present in all studied compositions as individual phases
and form no compounds or solid solutions. The oxide coating containing 70 at. % Co and 30 at. % Sn reveals a maximum electrocatalytic
activity. The existence of the optimum composition is attributed to a favorable effect tin dioxide has on the formation of
a transition layer between the Ti support and oxide coating. Tin dioxide hampers the Ti diffusion in the main coating and
its subsequent oxidation, thus diminishing the negative impact titanium oxides have on the coating 相似文献
10.
I. I. Simentsova T. P. Minyukova A. A. Khassin E. V. Dokuchits L. P. Davydova I. Yu. Molina L. M. Plyasova G. N. Kustova T. M. Yurieva 《Russian Chemical Bulletin》2010,59(11):2055-2060
The influence of the Ni2+/Cr3+ ratio in the precursor compound on the formation of the catalyst structure and its transformation upon the thermal treatment and reductive activation in hydrogen was studied. The precursors with the cation ratio Ni2+/Cr3+ = (2.3–3)/1 represent a homogeneous system of the stichtite-type structure. The treatment of the precursors at T ~400 °C in an inert atmosphere forms a nanosized phase of the NiO-type structure with the lattice parameter a = 4.186±0.005 Å. At 600 °C the lattice parameter of this phase decreases to the tabulated value (a = 4.177±0.005 Å). The phase of nickel chromite of the cubic spinel structure with the lattice parameter a = 8.320±0.005 Å is also observed. Hydrogen activation of the catalyst preheated at 300 °C in an inert gas leads to the formation of Ni0 crystallites with a size of ~5.5 nm and a specific surface area of ~7.0 m2 g?1. This catalyst exhibits high activity and selectivity in benzene hydrogenation and preferential CO hydrogenation in the presence of CO2. The catalysts with the ratio Ni2+/Cr3+ = 1/(2?3) containing nickel and chromium hydroxocarbonates as precursors are less active in the hydrogenation of benzene to cyclohexane. 相似文献
11.
KeQiangDING QingFeiWANG RuTingTONG HuiBoSHAO 《中国化学快报》2003,14(4):411-412
In this paper,the membrane capacitance(Cm),which was obtained from the ecectrochemical impedance spectroscopy(EIS) method,was used to characterize the effect of pH value on the self-assembled monolayers(SAMs) of octadecanethiol(18SH) for the first time.The results not only strongly proved that inorganic ions could penetrate the SAMs of 18SH,but also ascertained that SAMs of 18SH were not an absolute of free of ion-penetration.Verifying the existence of pin-holes in the octadecanethiol SAMs was the main contribution of this paper,which coincided with the former conjecture very well. 相似文献
12.
The potential energy surfaces of the HN—O2 and PhN—O2 systems were calculated by the MP2 and B3LYP methods. The mechanism of photooxidation of azides was refined. Photooxidation produces the nitrene—O2 adducts with dioxaziridine and non-cyclic structures. The parameters of IR spectra of the adducts were calculated. The rearrangement of dioxaziridine to a nitro compound is likely a reason for chemiluminescence accompanying the photooxidation of azides. 相似文献
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Journal of Structural Chemistry - 相似文献
14.
Photopolymerization of methyl methacrylate in the presence of the tri-n-butyl boron—p-quinone system
Yu. L. Kuznetsova S. A. Chesnokov S. D. Zaitsev V. A. Dodonov 《Polymer Science Series B》2010,52(3-4):129-135
The photopolymerization of methyl methacrylate in the presence of tri-n-butyl boron and a number of p-quinones is studied in a wide concentration range. It is shown that the rate of polymerization and the molecular-mass characteristics of the polymers depend on the structure and concentration of p-quinone. PMMA isolated at various conversions initiates the secondary polymerization of methyl methacrylate. The activity of the macroinitator depends on the structure of p-quinone. 相似文献
15.
K. Sarayu Nagesh R. Iyer A. Ramachandra Murthy 《Applied biochemistry and biotechnology》2014,172(5):2308-2323
Biomineralization is a process that leads to the formation of minerals using the biologically or biotechnologically mediated route. Calcium carbonate is one such biomineral that is secreted by the ureolytic bacteria which contributes for the strengthening and improvement of cementitious and sandy materials. It is a new and innovative area in the geotechnological engineering and structural engineering due to its wide range of implications in strengthening of soil, sand, stone, and cementitious materials. The shape and size of the calcium carbonate particle vary with the strain of the bacterium used, and it is species specific. This paper aims in the critical review of the mechanism of calcium carbonate precipitation by the bacterium, various bacteria involved, and the useful outputs of the technique of biomineralization. Based on the critical review, it also recommends the future development and research in the field to develop a technology that can strengthen the existing and the proposed structures. 相似文献
16.
Florian Mansfeld 《Journal of Solid State Electrochemistry》2009,13(4):515-520
The work of Oldham and Mansfeld dealing with the concept of the polarization resistance technique that can be used to determine
corrosion rates from potential E—current I curves measured in the vicinity of the corrosion potential E
corr has been summarized. In addressing the interpretation of this technique as the “linear polarization (resistance) technique,”
Oldham and Mansfeld pointed out that curvature of polarization curves in the vicinity of E
corr has to occur in order for the Butler–Volmer equation, as modified for corrosion reactions, to be valid. They proposed a modification
of the Stern–Geary linear polarization equation and presented a new graphical method for the calculation of corrosion rates
from polarization curves. Some of the earliest computer programs for the determination of corrosion current densities, and
Tafel slopes from polarization data collected in the vicinity of E
corr and examples of their application have been discussed.
Dedicated to the 80th birthday of Keith B. Oldham. 相似文献
17.
ChaoxianXiao ZhenYan: YuanKou 《天然气化学杂志》2003,12(2):90-92
NOx-catalyzed oxidation of methane without a solid catalyst was investigated, and a hydrogen selectivity of 27% was obtained with an overall methane conversion of 34% and a free O2 concentration of 1.7% at 700℃. 相似文献
18.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1994,50(14):2271-2280
The dimer approach was proposed for the normal coordinate analysis of BEDT—TTF+ molecular vibrations. It was shown that, within the framework of the approximation used, the appearance of additional bands in the IR as well as in Raman spectra may be explained as due to the reduction of symmetry of the dimerized system in comparison with the monomeric one. The strength of intermolecular interaction in the dimer was estimated by adjusting the calculated frequencies to the observed positions of intense “vibronic” bands recorded in the IR spectra of BEDT—TTF-based monovalent charge transfer salts. It was found that for the reproduction of “vibronic shifts” observed for some vibrations it should be assumed that the intermolecular interaction takes effect not only on the totally symmetric ag modes, but also on the vibrations of other symmetry species. 相似文献
19.
The effect of the saturability of noncovalent interactions on the character of opioid activity of opioid receptor ligands belonging to different structural classes was investigated. A three-dimensional model for an opiate pharmacophore was used to show that the involvement of pharmacophore elements, which are responsible for the agonist ligand binding to opioid receptors, in intramolecular interactions gives rise to antagonistic properties. 相似文献
20.
Izabela Michalak Katarzyna Chojnacka Anna Witek-Krowiak 《Applied biochemistry and biotechnology》2013,170(6):1389-1416
In recent years, biosorption process has become an economic and eco-friendly alternative treatment technology in the water and wastewater industry. In this light, a number of biosorbents were developed and are successfully employed for treating various pollutants including metals, dyes, phenols, fluoride, and pharmaceuticals in solutions (aqueous/oil). However, still there are few technical barriers in the biosorption process that impede its commercialization and thus to overcome these problems there has been a steadily growing interest in this research field. This resulted in large numbers of publications and patents each year. This review reports the state of the art in biosorption research. In this review, we provide a compendium of know-how in laboratory methodology, mathematical modeling of equilibrium and kinetics, identification of the biosorption mechanism. Various mathematical models of biosorption were discussed: the process in packed-bed column arrangement, as well as by suspended biomass. Particular attention was paid to patents in biosorption and pilot-scale systems. In addition, we provided future aspects in biosorption research. 相似文献