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51.
Widely tunable terahertz (THz)-wave generation using difference frequency generation (DFG) in an organic N-benzyl-2-methyl-4-nitroaniline (BNA) crystal was demonstrated. To our knowledge, this is the first report of THz-wave generation by BNA DFG. Large, high-quality single crystals of BNA (phi 8 mm x 30 mm) were grown using the vertical Bridgman method. The nonlinear optical (NLO) coefficient d(33) of the BNA crystal is approximately 234 pm/V, which is the largest value reported for any yellow NLO material. The collinear phase-matching condition of the type-0 configuration is satisfied using a 0.7-1 microm band pump wavelength. We generated THz waves using an organic BNA crystal; the generation range is 0.1-15 THz. 相似文献
52.
Hiromasa Nishikiori Rudi Agus Setiawan Kyohei Miyashita Katsuya Teshima Tsuneo Fujii 《Photochemistry and photobiology》2014,90(4):747-759
Fluorescein‐dispersing titania gel films were prepared by the acid‐catalyzed sol–gel reaction using a titanium alkoxide solution containing fluorescein. The molecular forms of fluorescein in the films, depending on its acid–base equilibria, and the complex formation and photoinduced electron transfer process between the dye and titania surface were investigated by fluorescence and photoelectric measurements. The titanium species were coordinated to the carboxylate and phenolate‐like groups of the fluorescein species. The quantum efficiencies of the fluorescence quenching and photoelectric conversion were higher upon excitation of the dianion species interacting with the titania, i.e. the dye–titania complex. This result indicated that the dianion form was the most favorable for formation of the dye–titania complex exhibiting the highest electron transfer efficiency. Using nitric acid as the catalyst, the titania surface bonded to the fluorescein instead of the adsorbed nitrate ion during the steam treatment. The dye–titania complex formation played an important role in the electron injection from the dye to the titania conduction band. 相似文献
53.
Taichi Mitsumoto Dr. Yuya Ashida Dr. Kazuya Arashiba Dr. Shogo Kuriyama Akihito Egi Prof. Dr. Hiromasa Tanaka Prof. Dr. Kazunari Yoshizawa Prof. Dr. Yoshiaki Nishibayashi 《Angewandte Chemie (International ed. in English)》2023,62(43):e202306631
We newly designed and prepared a novel molybdenum complex bearing a 4-[3,5-bis(trifluoromethyl)phenyl]pyridine-based PNP-type pincer ligand, based on the bond dissociation free energies (BDFEs) of the N−H bonds in molybdenum-imide complexes bearing various substituted pyridine-based PNP-type pincer ligands. The complex worked as an excellent catalyst toward ammonia formation from the reaction of an atmospheric pressure of dinitrogen with samarium diiodide as a reductant and water as a proton source under ambient reaction conditions, where up to 3580 equivalents of ammonia were formed based on the molybdenum atom of the catalyst. The catalytic activity was significantly improved by one order of magnitude larger than that observed when using the complex before modification. 相似文献
54.
Inside Cover: Direct Transformation of Molecular Dinitrogen into Ammonia Catalyzed by Cobalt Dinitrogen Complexes Bearing Anionic PNP Pincer Ligands (Angew. Chem. Int. Ed. 46/2016)
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55.
Tomoyuki Miyao Hiromasa Kaneko Kimito Funatsu 《Journal of computer-aided molecular design》2016,30(5):425-446
Generating chemical graphs in silico by combining building blocks is important and fundamental in virtual combinatorial chemistry. A premise in this area is that generated structures should be irredundant as well as exhaustive. In this study, we develop structure generation algorithms regarding combining ring systems as well as atom fragments. The proposed algorithms consist of three parts. First, chemical structures are generated through a canonical construction path. During structure generation, ring systems can be treated as reduced graphs having fewer vertices than those in the original ones. Second, diversified structures are generated by a simple rule-based generation algorithm. Third, the number of structures to be generated can be estimated with adequate accuracy without actual exhaustive generation. The proposed algorithms were implemented in structure generator Molgilla. As a practical application, Molgilla generated chemical structures mimicking rosiglitazone in terms of a two dimensional pharmacophore pattern. The strength of the algorithms lies in simplicity and flexibility. Therefore, they may be applied to various computer programs regarding structure generation by combining building blocks. 相似文献
56.
Direct Transformation of Molecular Dinitrogen into Ammonia Catalyzed by Cobalt Dinitrogen Complexes Bearing Anionic PNP Pincer Ligands
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Dr. Shogo Kuriyama Dr. Kazuya Arashiba Prof. Dr. Hiromasa Tanaka Yuki Matsuo Dr. Kazunari Nakajima Prof. Dr. Kazunari Yoshizawa Prof. Dr. Yoshiaki Nishibayashi 《Angewandte Chemie (International ed. in English)》2016,55(46):14291-14295
The direct formation of ammonia from molecular dinitrogen under mild reaction conditions was achieved by using new cobalt dinitrogen complexes bearing an anionic PNP‐type pincer ligand. Up to 15.9 equivalents of ammonia were produced based on the amount of catalyst together with 1.0 equivalent of hydrazine (17.9 equiv of fixed nitrogen atoms). 相似文献
57.
Kouki Ikuta Tsutomu Kudo Noboru Yoshikane Nilesh J. Vasa Yuji Oki Mitsuo Maeda 《Optical Review》1999,6(5):464-470
Improvement of an infrared light detection and ranging (IR-lidar) system for a short range (0–1000 m) and with high resolution is studied to enhance a geometrical form factor. Theoretical modeling of Mie scattering echo signals agrees with the experimental results. Introduction of a lens in front of the detector is effective for increasing the geometrical form factor, and a significant improvement in the received signal intensity is achieved, especially for short-range measurements around 100 m. This is useful for the IR-lidar system with a detector diameter of less than 1 mm. In the theoretical model, a ray-tracing technique was applied and a transmitting laser beam with Gaussian profile was considered for better accuracy. 相似文献
58.
59.
Akihiko Nakatsuka Yasuaki Ikuta Akira Yoshiasa Kazuake Iishi 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(12):i133-i135
The vanadate garnet Ca2NaMg2V3O12 (dicalcium sodium dimagnesium trivanadium dodecaoxide), synthesized by a floating zone method, has a notable structural feature in that the dodecahedral–dodecahedral shared edge length is longer than the unshared dodecahedral edge length. It is also noteworthy that the octahedral–dodecahedral shared edge length is as long as the unshared octahedral edge length. These unusual structural features are closely related to the weak repulsions between dodecahedral cations and between dodecahedral and octahedral cations. 相似文献
60.
Zhongqi Xu Toshiaki EsumiNatsuki Ikuta Takeshi Hirokawa 《Journal of chromatography. A》2009,1216(17):3602-3605
In this report aimed on further development of a high-sensitivity capillary gel electrophoresis (CGE) method for analysis of DNA fragments, we firstly explored online transient isotachophoresis (tITP) preconcentration combined with fluorescence detection (FD). The fluorescence signal (excitation: 488 nm; emission: 590 nm) was generated using the intercalating dye of ethidium bromide (EB). It was found when the leading electrolyte (LE) was injected behind the sample zone, such a special tITP mode has significant advantages to solve the bubble formation issue and to improve the analytical performance stability. Two standard DNA samples, a 50 bp DNA step ladder and the φX174/HaeIII digest, were used to evaluate the qualitative and quantitative abilities of the tITP-FD approach. A highly diluted sample (10,000-fold in the water, e.g. the φX174/HaeIII digest diluted from 500 μg/ml to the 50 ng/ml level) was enriched and detected; the LOD was down to 0.09 ng/ml for the 72 bp fragment, apparently improved more than 1000-fold in comparison with UV detection. Although the RSD of peak areas (n = 3) was around 15.5% for the sample was electrokinetically injected, good linearity of peak area response showed that the proposed method is suitable for quantitative analysis. 相似文献