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971.
The reaction of [(trimethylsilyl)imino]methyldiphenylphosphorane: Ph2MePNSiMe3 (I) with several acid anhydrides or alkyl isocyanates took place by the simple cleavage of silicon-nitrogen bond. In contrast the interaction of (I) with phenyl isocyanate, isothiocyanate or carbon disulphide led to addition-elimination reactions of the Wittig type. Detailed investigation in the case of phenyl isocyanate indicated the usual elimination of Ph2MePO is suppressed by the strong affinity of the trimethylsilyl group for anionic oxygen atom. 相似文献
972.
If the absorption of a trapped electron can be shown to correspond to bound—free transitions, it should be possible to calculate the potential acting on the trapped electron inversely from its absorption spectrum. In this paper we present the method of calculating the potential acting on a trapped electron from the observed absorption spectrum. 相似文献
973.
6,7-Dimethoxy-2-naphthylethylamine, prepared by the diborane reduction of 6,7-dimethoxy-2-naphtlialeneacetamide, underwent a Pictet-Spengler cyclization to form 8,9-dimethoxy-1,2,3,4-tetrahydrobenz[h]isoquinoline. This compound is identical with that obtained by reduction of the corresponding dihydrobenzisoquinoline prepared from formamide cyclization. 6,7-Dialkoxy-2-naphthaleneacetic acids, the key intermediates for the preparation of these amides, were obtained from 6,7-dialkoxy-2-acetonaphthones by a modified Willgerodt reaction. 相似文献
974.
975.
Y. Takashima 《Journal of Radioanalytical and Nuclear Chemistry》1993,171(1):95-100
The Kyushu Museum of Energy, funded by the Kyushu Electric Power Company, Inc., was opened in September 1982. The planning and design were done by Dentsu, Inc., and the actual construction was shared among several construction and manufacturing companies. I was retained as the principal scientific advisor for the museum, both prior to its construction, throughhout the planning of the exhibits, and afterwards when it was opened to the public. This is an educational museum, which shows how people have developed and depended on energy and energy sources since the discovery of fire in prehistory. There are four major sections, devoted to fire itself, electricity, nuclear power by fission, and nuclear power by fusion. In addition, the museum will track visitors through the exhibits, in terms of The History of Energy as a beginning point for their tour, lead them through Present Energy Needs and Uses, and thence to Future Energy Developments and Needs. The museum is of a hands-on active display type design, with many large and attractive display panels, working models, pleasant mixes of sound, light, and images, and educational levels that encompass general public interest to semitechnical explanations that will satisfy the undergraduate with a technical, background. Visitors can not only operate the models themselves, but join in a variety of games based on energy consumption, usage, and needs. It is very much a participatory museum, and visitors are exposed to the many facets of day-to-day energy generation and consumption, as well as the estimated needs for the future, and possible ways to supply these needs. To date, there have been well over 200,000 visitors recorded. *** DIRECT SUPPORT *** A0653119 00004 相似文献
976.
N,N-dimethyl-N,N-dihexyl-3-oxapentanediamide, DMDHOPDA, N,N-dihexyl-3-thiopentanediamide, DHTPDA and N,N-dihexyl-3-oxapentanediamide, DHOPDA were synthesized and tested for the synergistic extraction of Eu3+, Th4+, UO
2
2+
, NpO
2
+
and Am3+ with thenoyltrifluoroacetone (HTTA). Although Eu3+, Th4+, UO
2
2+
and Am3+ were not extracted by DHTPDA or DHOPDA alone, they were extracted synergistically when combined with HTTA. Analysis of the dependency of extraction on pH and extractant concentration indicated that the dominant extracted species were Eu(TTA)3(A), Th(TTA)3(A)(X), UO2(TTA)2(A) and Am(TTA)3(A) (where A is diamide, and X is chloroacetate or ClO
4
–
). 相似文献
977.
J. C. Y. Le Blanc D. Beuchemin K. W. M. Siu R. Guevremont S. S. Berman 《Journal of mass spectrometry : JMS》1991,26(10):831-839
The effects of beat on the electrospray mass spectra of eight globular proteins in solution were studied. These ranged from hardly noticeable to a dramatic shift in the mass spectrometric profile and a concomitant increase in ion abundance. This change is believed to be the result of thermal denaturation of the protein species in solution resulting in a transition from a more compact to a less compact conformation. We accounted for this transition by means of a recently proposed model based on aqueous solution acid/base equilibria. For cytochrome c, profiles calculated by means of this model agree well with experimental data. The ΔH of the denaturation reaction of cytochrome c in aqueous solution containing 0.2% acetic acid was calculated from experimental data to be 103.8 ± 9.2 kJ mol?1, in good agreement with previous measurements. 相似文献
978.
Simple heteroarenes such as pyrroles and indoles undergo addition reactions to C-C triple bonds in the presence of a catalytic amount of Pd(OAc)(2) under very mild conditions, affording cis-heteroarylalkenes in most cases. The cleavage of aromatic C-H bonds is the possible rate-determining step in CH(2)Cl(2), and the addition of heteroaromatic C-H bonds to C-C triple bonds is in a trans-fashion. 相似文献
979.
[reaction: see text] A microwave-assisted reaction was developed to facilitate the construction of 4,5-disubstituted pyrazolopyrimidines. This one-pot two-step process involves a sequential S(N)Ar displacement of the C4 chloro substituent with various anilines and amines, followed by a Suzuki coupling reaction with different boronic acids. Using microwave irradiation leads to high product conversion, low side product formation, and shorter reactions. 相似文献
980.
A new study of the enzymatic hydrolysis of carboxymethyl cellulose with a bulk acoustic wave sensor 总被引:4,自引:0,他引:4
A new bulk acoustic wave (BAW) cellulase sensing technique, which is based on the enzymatic hydrolysis process of sodium carboxymethylcellulose (CMC) by cellulase, was established. The frequency shift curves of BAW sensor indicated that the viscosity of the tested solutions decreased during the hydrolysis process. The hydrolysis rate of CMC by cellulase was calculated from the frequency shift curves. The hydrolysis rate of CMC under different pH conditions at 30°C showed that cellulase had high hydrolysis ability approximately at pH 5.0. Kinetic parameters (the Michaelis constant Km and the maximum rate Vmax) of the process were estimated by using a linear method of Lineweaver–Burk plot. Km is 1.95±0.25 mg ml−1 and Vmax is −(4.25±0.58)×10−3 g1/2 cm−3/2 cP1/2 min−1. Also the activation energy (Ea) of the enzymatic hydrolysis, with a value of 51.99±1.26 kJ mol−1, was estimated in this work. 相似文献