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排序方式: 共有179条查询结果,搜索用时 31 毫秒
51.
52.
Yusaku Honjo Dr. Yu Shibata Prof. Dr. Ken Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(40):9427-9432
It has been established that an electron-deficient cyclopentadienyl rhodium(III) (CpERhIII) complex catalyzes the oxidative and decarboxylative [2+1+2+1] cycloaddition of benzoic acids with diynes through C≡C triple bond cleavage, leading to fused naphthalenes. This cyclotrimerization is initiated by directed ortho C−H bond cleavage of a benzoic acid, and the subsequent regioselective alkyne insertion and decarboxylation produce a five-membered rhodacycle. The electron-deficient nature of the CpERhIII complex promotes reductive elimination giving a cyclobutadiene–rhodium(I) complex rather than the second intermolecular alkyne insertion. The oxidative addition of the thus generated cyclobutadiene to rhodium(I) (formal C≡C triple bond cleavage) followed by the second intramolecular alkyne insertion and reductive elimination give the corresponding [2+1+2+1] cycloaddition product. The synthetic utility of the present [2+1+2+1] cycloaddition was demonstrated in the facile synthesis of a donor–acceptor [5]helicene and a hemi-hexabenzocoronene by a combination with the chemoselective Scholl reaction. 相似文献
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Chae-Hyoung Kim In-Seuck Jeung Byungil Choi Toshinori Kouchi Kenichi Takita Goro Masuya 《Proceedings of the Combustion Institute》2011,33(2):2375-2382
Non-reacting and reacting experiments on the ignition by a plasma jet (PJ) torch were performed to understand the correlation between fuel injection location and combustion characteristics in unheated Mach 2 airflow. Fuel was injected through three sonic injectors in the recirculation region behind a backward-facing step: a parallel injector at 2 mm from the bottom wall and two normal injectors at 2 and 9 mm from the step wall. In order to mitigate the combustion pressure interaction with nozzle, an isolator was installed between the nozzle and combustor. The combustion performance of normal injection was little affected by the difference of fuel injection locations. Moreover, normally injected fuel was escaped not to be held in the recirculation region despite of low fuel injection rates. This led to lower combustion performance relative to the parallel injection which provided fuel not to leave the recirculation region. In this case, the role of the recirculation region was to fully hold fuel, and the PJ torch provided hot gases as a heat source and acted as a flame-holder to ignite fuel–air mixtures. In a low temperature inflow condition, combustible regions were constrained around the bottom wall where embedded with the PJ torch. When thermal choking occurred in the combustor, it induced shock train both in the combustor and isolator. Under this unstable condition, the combustion performance of the normal injection was lower than that of the parallel injection. This is because the normal injection led most fuel into low temperature incoming air-stream. 相似文献
55.
LaGaO3-based perovskite oxide doped with Sr and Mg exhibits high ionic conduction over a wide oxygen partial pressure. In this study,
the stability of the LaGaO3 based oxide was investigated. It became clear that LaGaO3 based oxide is very stable for reduction and oxidation. SOFCs utilizing LaGaO3-based perovskite type oxide for electrolyte were further studied for the decreased temperature solid oxide fuel cells. The
power generation characteristics of cells were strongly affected by the electrode, both anode and cathode. It became clear
that Ni and LnCoO3 (Ln: rare earth) are suitable for anode and cathode, respectively. Rare earth cations in the Ln-site of Co-based perovskite
cathode also have a great effect on the power generation characteristics. In particular, high power density could be attained
in the temperature range from 973 to 1273 K by using doped SmCoO3 for the cathode. The electrical conductivity of SmCoO3 increases with increasing Sr amount doped for the Sm site and attained the maximum at Sm0.5Sr0.5CoO3. The cathodic overpotential and the internal cell resistance exhibit almost opposite dependence on the amount of doped Sr.
Consequently, the power density of the cell reaches a maximum when Sm0.5Sr0.5CoO3 is used for cathode. On this cell, the maximum power density is as high as 0.58 W/cm2 at 1073 K, although a 0.5 mm thick electrolyte is used. Therefore, this study reveals that the LaGaO3 based oxide for electrolyte and the SmCoO3 based oxide for cathode are promising for solid oxide fuel cells at intermediate temperature.
Paper presented at the 97th Xiangshan Science Conference on New Solid State Fuel Cells, Xiangshan, Beijing, China, June, 14–17,
1998. 相似文献
56.
Shigehiro Kagaya Yusaku Hosomori Hidekazu Arai Kiyoshi Hasegawa 《Analytical sciences》2003,19(7):1061-1064
Cadmium ranging from 1 - 8 ng could be coprecipitated quantitatively with lanthanum phosphate at pH 5 - 6 from up to 200 mL of river water samples spiked with 5 microg of indium as an internal standard. Cadmium and indium coprecipitated were measured by using electrothermal atomic absorption spectrometry. The cadmium content in the original sample solution could be determined by internal standardization with indium. Since complete collection of the precipitate and strict adjustment of the volume of the final solution after coprecipitation are not required in this method, the precipitate could be collected by using decantation and centrifugation, and then dissolved with 1 mL of about 2.4 mol L(-1) nitric acid. The proposed method is simple and rapid, and enrichment close to 200-times can be attained; the detection limit (3sigma, n = 6) was 0.63 ng L(-1) in 200 mL of the sample solution. 相似文献
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59.
Ming Wen Megumu Munakata Yi-Zhi Li Yusaku Suenaga Takayoshi Kuroda-Sowa Masahiko Maekawa Manabu Anahata 《Polyhedron》2007
For the purpose of investigating the coordination behavior of sterically congested alkenes and exploring the possibility of non-planar complexation in the polycyclic aromatic system for formation of extended polymeric networks, triptycene (tpty) has been studied with regard to its complexation with the silver(I) ion. The crystal structures of [Ag(tpty)(THF)2](ClO4) (1) and [Ag6(tpty)4(CF3SO3)2(H2O)6](CF3SO3)4 (2) have been determined by single-crystal X-ray diffraction. The polycyclic aromatic hydrocarbon triptycene is found to offer a potential site for complexation, which can be utilized to generate an interesting array of organo-metallic polymers with one-dimensional (1D) chain and three-dimensional (3D) porous frameworks. 相似文献
60.
Perfluoroalkyl and ‐aryl Zinc Ate Complexes: Generation,Reactivity, and Synthetic Application 下载免费PDF全文
Dr. Xuan Wang Dr. Keiichi Hirano Daisuke Kurauchi Hisano Kato Naoyuki Toriumi Dr. Ryo Takita Prof. Dr. Masanobu Uchiyama 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):10993-10996
A combination of dimethylzinc, perfluoroalkyl iodide, and LiCl afforded a new type of perfluoroalkyl (RF) zinc ate complex. These complexes show much greater thermal stability than conventional perfluorinated metal species, such as RF–lithium species and Grignard reagents, and they can be used at room temperature or higher. The results of DFT calculations on the origin of the enhanced stability are reported and the synthetic utility of RF‐zincate complexes is demonstrated. 相似文献