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1.
It is shown how, with the help of approximate integral manifolds, to solve the reduction problem in stability theory in the nonsingular critical case. A generalization of the first fundamental Lyapunov-Malkin theorem in critical cases is obtained.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 43, No. 10, pp. 1324–1329, October, 1991. 相似文献
2.
Ayhan S. Demir Ömer Reis Ilker Esiringü Barbaros Reis Sehriban Baris 《Tetrahedron》2007,63(1):160-165
Acylphosphonates, which are easily available from carboxylic acids, are potent acyl anion precursors and undergo cyanide ion promoted phosphonate-phosphate rearrangement to provide the corresponding acyl anion equivalents as reactive intermediates. The protonation of these acyl anion equivalents furnished cyanohydrin O-phosphates in good yields. For the high yield formation of cyanohydrin O-phosphates from arylphosphonates THF should be used and from alkylphosphonates DME was used. 相似文献
3.
Growing environmental concerns and the need for alternatives for oil
and natural gas resulted in intensive researches on ultra clean coal (UCC).
Therefore, the researches related to practice and application of various methods
to produce UCC become more important. Thermal characterization of chemically
demineralized coals by thermogravimetric analysis method is presented in this
study. The aim of the study is to provide thermal data for HF–HNO3
leaching system used for the production of UCC. Coal samples were first physically
enriched by density separation. Then the enriched portion was chemically demineralized
by using HF and HNO3, respectively. Ash content of coal samples were reduced
to a range of 0.12–0.41% by chemical demineralization process. The petrographic,
ultimate and proximate analyses were carried out to determine main features
of samples. Physically and chemically enriched coal samples were then analyzed
in a TG by two different techniques separately. The first technique covered
thermal characterization of samples under non-isothermal conditions. Characteristic
temperatures for each sample were obtained from the TG and DTG data. The second
technique involved the determination of reactivity of in situ produced chars
of each sample. 相似文献
4.
Ersan Ronak Haj Alagoz Mehmet Abdullah Ertan-Bolelli Tugba Duran Nizami Burmaoglu Serdar Algul Oztekin 《Molecular diversity》2021,25(4):2247-2259
Molecular Diversity - In the present work, a series of bisbenzazole derivatives were designed and synthesized as antiproliferative agents. The antiproliferative activity of these compounds was... 相似文献
5.
The aim of this Letter is to show that, the Nusselt number sign might be changed without changing of heat transfer direction at the wall of channels, even for flows without viscous dissipation. 相似文献
6.
Unexpected formation of β, meso-directly linked diporphyrin products has been described in the reactions of β-formyl porphyrins with pyrrole under Adler–Longo reaction conditions. Preliminary mechanistic studies indicates that β-dipyrromethane substituted porphyrin structure is the crucial intermediate for the formation of diporphyrin product. 相似文献
7.
Baris Gure Niyazi Bicak 《Journal of polymer science. Part A, Polymer chemistry》2012,50(17):3575-3579
A method is presented for generation of all surface‐bound radicals on solid polymer surfaces. Thus, secondary amide group of newly synthesized crosslinking comonomer, methacryloyloxyethyl methacrylamide was determined as versatile precursor for generation fixed diradicals on solid microspheres, obtained by copolymerization with methyl methacrylate (MMA) in aqueous suspension. Nitrosoation of the secondary amide groups on the microbeads and followed thermolysis above 90 °C was demonstrated to give surface‐bound radicals, capable of initiating polymerization of vinyl monomers, such as; styrene, MMA, N‐vinyl formamide, and N‐vinyl, 2‐pyrrolidone, as evidenced by H NMR, Fourier transform infrared, thermogravimetric analysis, and differential scanning calorimeter techniques. Appreciable grafting yields (55.1%–286.1%) and low free‐homopolymer formation (7.2%–19.7%) were noted within 6 h of the grafting at 100 °C in each case. This strategy involving the use of amide functional crosslinker seemed to be generally applicable to generate surface‐bound radicals for surface‐initiated polymerization from various solid substrates. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
8.
9.
The selective synthesis of [26]hexaphyrin(1.1.1.1.1.1) has been achieved by the reaction of meso-substituted tripyrrane and N-sulfonyl aldimine. The protocol is simple and requires only a catalytic amount of copper(II) triflate under mild reaction conditions. 相似文献
10.