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排序方式: 共有112条查询结果,搜索用时 406 毫秒
1.
Katoh Katsumi Fukui Satomi Haba Ayane Higashi Eiko Saburi Tei Okada Ken 《Journal of Thermal Analysis and Calorimetry》2022,147(13):7563-7571
Journal of Thermal Analysis and Calorimetry - Nitrocellulose (NC) is prone to spontaneous decomposition with exothermic heat release and thus is generally evaluated for stability during the storage... 相似文献
2.
Eiko Yasui 《Tetrahedron letters》2006,47(5):743-746
A novel method for synthesizing arylhydrazones, the precursor for Fischer indole synthesis, using aryllithium reagents and α-diazo esters that are easily obtained from α-amino acid esters, is described. 相似文献
3.
4.
Yohei Hashimoto Masataka Moriyasu Eiko Kato Masaru Endo Naohiko Miyamoto Hiroshi Uchida 《Mikrochimica acta》1978,70(1-2):159-167
Summary A new type of detector for high-pressure liquid chromatography has been designed. This detector is equipped with a RC resonance circuit, and is similar to the capacitance detector previously reported. It is operated as a capacitance detector with nonpolar eluents; while with polar solvents, it behaves as a conductance detector. Electrolytes such as salts, acids and bases are sensitively detected. The detector was successfully used for the detection of fatty acids and alkaloids.
Zusammenfassung Ein neuartiger Detektor für die Hochdruck-Flüssigchromatographie wurde entwickelt. Dieser ist mit einem Resonanzstromkreis ausgestattet und ähnelt dem kürzlich beschriebenen Kapazitanz-Detektor. Als solcher funktioniert er mit nichtpolaren Eluenten, während er sich mit polaren Lösungsmitteln wie ein Leitfähigkeitsdetektor verhält. Salze, Säuren und Basen werden empfindlich nachgewiesen. Das Gerät wurde zum Nachweis von Fettsäuren und Alkaloiden verwendet.相似文献
5.
In order to interpret abrupt changes of distributions of orientations andmagnitudes of hyperfine fields in Mössbauer measurements of57Fe in YFeMnO4, a model is proposed. The origin is assumed to be not static but dynamic. Fluctuating fields are caused by spins in a fully frustrated spin system, namely, a Heisenberg spin system on a triangular lattice in a two-dimensional antiferromagnet. Extending the stochastic theory for the fluctuation between two states to that among many states with a Gaussian distribution, we fit the spectra with three parameters, hyperfine fieldH
hf, correlation time c, andwidth of fluctuating field , within a limited condition of =c=1. Obtained results represent the characteristic features of Mössbauer spectra well, in spite of a simplified model. 相似文献
6.
Eiko Hiroike 《Chemical physics letters》1981,78(2):323-327
The exchange dephasing model is investigated theoretically. An equation of motion satisfied by a reduced density matrix for the observed high-frequency mode is derived by a cumulant perturbation expansion method up to fourth order. The calculation shows a temperature dependence of the width and shift of the spectral line. 相似文献
7.
A tritriacontanucleotide which has the sequence of the 5half molecule of E.coli glycine tRNA2, was synthesized by the phosphotriester method involving p-anisidate protection for the 3phosphate ends. Di- and trinucleotide units were prepared from 5dimethoxytrityl-2O-tetrahydrofuranyl-3?-O-(o-chlorophenyl)phosphoryl derivatives of uridine, N-benzoylcytidine, N-benzolyadenosine and N-iso-butyrylguanosine by condensation with 35unprotected nucleosides followed by phosphorylation to give 3phosphodiester blocks. The 3terminal dimers and trimers were synthesized by using 3(o- chlorophenyl)phosphoro-p-anisidates instead of 3?,5?-unprotected nucleosides. The 3?-phosphodiesters of oligonucleotides with a chain length of larger than 5 were obtained by removal of the 3?-phosphoro-p-anisidate with isoamyl nitrite. The 5dimethoxytrityl group was removed by treatment with zinc bromide under anhydrous conditions. Fragments were designed to use common dimer blocks and to reduce the step for 5deblocking of larger fragments. Finally a 3phosphodiester block with a chain length of 20 was condensed with a 5OH component (tridecanucleotide). The fully protected 33 mer was deblocked and purified by chromatography. The structural integrity of the product was confirmed by mobility shift analysis and complete digestion with RNase T2. 相似文献
8.
The effect of metal ions on the conformation of thymine-containing poly-D-lysine was studied by CD spectra in aqueous solution. Of the metal ions studied, only copper(II) ion affected the conformation of nucleic acid analogs. Copper(II) ion also affected the specifically interacting system made up of thymine-containing poly-D-lysine and polyadenylic acid. 相似文献
9.
Abstract Ribozymes that distinguish a single base change in RNA were synthesized and used to specifically cleave c-Ha-ras messenger RNA. Using phosphorothioate containing oligonucleotide substrates, we have shown that Mg2+ binds to the pro-R oxygen of the phosphate and that the RNA cleavage reaction occurs via an in-line mechanism. Oligoribonucleotides containing a modified nucleoside are described. 相似文献
10.
Katsumi Katoh Seiichiro Nagayama Eiko Higashi Katsuyuki Nakano 《Journal of Thermal Analysis and Calorimetry》2013,113(3):1239-1244
In the hydrosilylation of 1,6-divinyl(perfluorohexane) (FDV) with trichlorosilane (TCS) in the presence of catalytic chloroplatinic acid (Pt-Cat) under an air atmosphere (0.99 MPa), a runaway reaction accompanied by a severe pressure release occurred when Fe2O3 was present as an impurity in the system. In this study, we investigated the mechanism of action of Fe2O3 on this hydrosilylation by monitoring the thermal behavior of TCS/FDV/Pt-Cat/Fe2O3 mixtures with various compositions, using an accelerating rate calorimeter (ARC). In the case of TSC/FDV/Pt-Cat, a typical hydrosilylation composition in the industrial process, heat release, possibly due to hydrosilylation, began at 90 °C. On the other hand, for TCS/FDV/Pt-Cat/Fe2O, the heat release due to hydrosilylation was hardly observed, but abrupt heat and pressure releases occurred at higher temperatures (>170 °C). Like TCS/FDV/Pt-Cat/Fe2O3, TCS/FDV, which contain neither Pt-Cat nor Fe2O3, released heat and pressure at high temperatures (>210 °C), while the heat and pressure release rates were comparatively low. From these results, the runaway reaction may occur when hydrosilylation is prevented, and Fe2O3 behaves as a negative catalyst for hydrosilylation. In the FT-IR spectrum of TCS/FDV/Pt-Cat/Fe2O3 after heating, an absorption peak at approximately 1,710 cm?1, which may be attributed to a carbonyl group, was observed. Thus, it is considered that the runaway reaction observed during the hydrosilylation results from the action of Fe2O3 as a negative catalyst for hydrosilylation as well as as an oxidation catalyst for the by-product generated from the reaction between TCS and FDV. 相似文献