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排序方式: 共有181条查询结果,搜索用时 15 毫秒
71.
Tomohisa Takita Yoji Umezawa Sei-ichi Saito Hajime Morishima Hamao Umezawa Yasuhiko Muraoka Masanobu Suzuki Masami Otsuka Susumu Kobayashi Masaji Ohno 《Tetrahedron letters》1981,22(7):671-674
Deglyco-bleomycin A2, the aglycon of bleomycin A2, has been synthesized for the first time. 相似文献
72.
Experimental study of color degree of freedom of gluons in e+e- annihilation at sqrt s around 60 GeV
Abe K Amako K Arai Y Asano Y Chiba M Chiba Y Daigo M Emura T Fukawa M Fukui T Fukushima Y Haba J Hemmi Y Higuchi M Hirose T Hojyo Y Homma Y Hoshi Y Ikegami Y Ishihara N Kamitani T Kanematsu N Kanzaki J Kikuchi R Kondo T Korhonen TT Koseki T Kurashige H Matsui T Minami M Miyake K Mori S Nagashima Y Nakamura T Nakano I Narita Y Odaka S Ogawa K Ohama T Ohsugi T Okamoto A Ono A Oyama T Sakamoto H Sakuda M Sasao N Sato M Shioden M Shirai J Shirakata M Sugimoto S Sumiyoshi T Suzuki A Suzuki Y 《Physical review letters》1991,66(3):280-284
73.
Munakata M Liu SQ Konaka H Kuroda-Sowa T Suenaga Y Maekawa M Nakagawa H Yamazaki Y 《Inorganic chemistry》2004,43(2):633-641
Reaction of [2.2]paracyclophane (pcp) with silver(I) trifluoroacetate (AgCF(3)CO(2)) and silver(I) pentafluoroproprionate (AgC(2)F(5)CO(2)) has led to isolation of three novel intercalation polymers: [Ag(4)(pcp)(CF(3)CO(2))(4)](C(6)H(6)) (1), [Ag(4)(pcp)(CF(3)CO(2))(4)](C(6)H(3)Me(3)) (2), and [Ag(4)(pcp)(C(2)F(5)CO(2))(4)](pcp) (3). Structure studies using single crystal X-ray diffraction have shown that all compounds contain two-dimensional layered frameworks based on cation-pi interactions, in which pcp exhibits an unprecedented micro-tetra-eta(2) coordination mode. Guest molecules which weakly interact with the host pcp via C-H.pi interactions are intercalated between layers. The guest-eliminated complexes (1a and 2a) and guest-reincorporated ones (1b or 1c and 2b or 2c), accompanied by small structural changes, were confirmed by (1)H NMR, thermogravimetric analysis, mass spectra, and X-ray powder diffraction patterns. The structural changes from 1 --> 1a --> 1c (=1) can take place reversibly in the process of exposure of 1a to benzene vapor. The original framework of complex 2 is also completely recovered by immersing 2a in mesitylene as well as exposing it to mesitylene vapor. 相似文献
74.
75.
Hirata KS Inoue K Ishida T Kajita T Kihara K Nakahata M Nakamura K Ohara S Sato N Totsuka Y Yaginuma Y Mori M Oyama Y Suzuki A Takahashi K Yamada M Suda T Tajima T Miyano K Miyata H Takei H Fukuda Y Kodera E Nagashima Y Takita M Kaneyuki K Tanimori T Beier EW Frank ED Frati W Kim SB Mann AK Newcomer FM Van Berg R Zhang W 《Physical review D: Particles and fields》1992,45(10):3355-3360
76.
Hirata KS Inoue K Ishida T Kajita T Kihara K Nakahata M Nakamura K Ohara S Sato N Suzuki Y Totsuka Y Yaginuma Y Mori M Oyama Y Suzuki A Takahashi K Yamada M Koshiba M Nishijima K Suda T Tajima T Miyano K Miyata H Takei H Fukuda Y Kodera E Nagashima Y Takita M Yokoyama H Kaneyuki K Takeuchi Y Tanimori T Beier EW Feldscher LR Frank ED Frati W Kim SB Mann AK Newcomer FM Van Berg R Zhang W 《Physical review D: Particles and fields》1992,45(6):2170
77.
Catalytic decomposition of CCI2F2 was studied over a number of single and complex metal oxides using a fixed-bed reactor. The ZrO2–Cr2O2 catalyst exhibited the highest activity and CO2 and CCIF3 were formed at 350–450°C. Selective decomposition of CCI2F2 required the presence of both oxygen and water vapor over the catalyst. Catalytic activity gradually declined with time on stream because of the fluorination of ZrO2. Treatment of the catalyst with both oxygen and water vapor promoted the removal of fluoride ions in sub-surface layers of the catalyst, which is effective for the recovery of the activity. CCI2F2 was decomposed at 300–450°C over AIPO4. No fluorination of the AIPO4 catalyst took place after the reaction for 1000 h. CH2FCF3, an alternative CFC, was completely decomposed over the mixed catalyst of Ce promoted AIPO4 and Cr2O3 at 400–500°C. Catalytic decomposition is a rational method for destruction of used CFCs. 相似文献
78.
Dr. Yuma Morimoto Yusaku Takagi Dr. Toru Saito Dr. Takehiro Ohta Prof. Dr. Norimitsu Tohnai Prof. Dr. Motohiro Nakano Prof. Dr. Shinobu Itoh 《Angewandte Chemie (International ed. in English)》2018,57(26):7640-7643
A bis(μ‐oxido)dinickel(III) complex was synthesized and characterized by single crystal X‐ray diffraction, resonance Raman, and ESI‐mass measurements. Magnetic susceptibility measurements by SQUID and EPR spectroscopy reveal that the complex has a triplet ground state, which is unprecedented for high‐valent metal (M) complexes with [M2(μ‐O)2] diamond core. DFT studies indicate ferromagnetic coupling of the nickel(III) centers. The complex exhibits hydrogen abstraction reactivity and oxygenation reactivity toward external substrates. 相似文献
79.
T. Ishihara K. Nishida H. Nishiguchi Y. Takita K. Chaki 《Research on Chemical Intermediates》2006,32(3):253-262
A new reforming process was studied using Ni/SiO2 with a hydrogen-permeating membrane reactor. Nickel catalyst supported on SiO2 is highly active for CH4-H2O-O2 reaction in membrane reactor and the reaction close to CH4 + 0.35O2 + 1.3H2O → CO2 + 3.3H2 proceeds at 873 K. Since the selectivity to carbon and CO2 increased and decreased with decreasing contact time respectively, it is considered that the reaction was started by decomposition
of CH4 followed by oxidation of C and water shift reaction. Therefore, the reaction mechanism was different from so-called autothermal
reforming (ATR) reaction. 相似文献
80.
Yusaku Migita Hiroshi Yokoyama Akiko Minami Takanori Mori Masaki Nojiri Shinnichiro Suzuki Kazuya Yamaguchi 《Electroanalysis》2009,21(22):2441-2446
The electrocatalytic reduction of nitrite to NO by [CuMe2bpa(H2O)(ClO4)]+ ( 1 ), which is a model for the active site of copper‐containing nitrite reductase, incorporated in Nafion film was investigated. The Cu complex in the Nafion matrix exhibits an intense band at 267 nm and a broad band around 680 nm, assigned to d–d and ligand field transitions, respectively. The 77‐K EPR spectrum of 1 in the Nafion matrix reveals the typical axial signals (g//=2.28, g =2.08, A//=13.3 mT) of a tetragonal Cu2+ chromophore. The redox potential, which is related to the Cu+/Cu2+ couple, was ?146 mV (ΔE=72 mV) at pH 5.5. The redox reaction of 1 in Nafion was not dependent on pH and was a diffusion‐controlled process. The electronic structure and redox properties of 1 in the negatively charged polymer matrix were almost the same as those in aqueous solution. In the presence of nitrite, an increase in the cathodic current was observed in the cyclic voltammogram of 1 in the Nafion matrix. The current increase was dependent on the nitrite concentration and pH in solution. Upon reaching ?400 mV, a linear generation of NO was observed for the 1 /Nafion film coated electrode. The relationship between the rate of NO generation and the nitrite concentration in solution was analyzed with the Michaelis–Menten equation, where Vmax=45.1 nM s?1 and Km=15.8 mM at pH 5.5. The Cu complex serves the function of both the catalyst and electron transport in the Nafion matrix. The sensitivity of the electrode was estimated to be 3.23 μA mM?1 in the range of 0.1–0.4 mM nitrite. 相似文献