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71.
72.
Teruji Tsuji Takahiro Kataoka Mitsuru Yoshioka Yuji Sendo Yasuhiro Nishitani Shoichi Hirai Takashi Maeda Wataru Nagata 《Tetrahedron letters》1979,20(30):2793-2796
The benzyl ester protecting group in β-lactam derivatives can be cleanly removed by treatment with aluminum trichloride under mild conditions, preferably in the presence of anisole, to give the corresponding free acids in high yields. 相似文献
73.
Yoshio Hamashima Tadatoshi Kubota Koji Ishikura Wataru Nagata 《Tetrahedron letters》1979,20(51):4943-4946
7-Epi-1-oxacephem was obtained by stereospecific, intramolecular etherification of alcohol prepared from 7-epicephems via aldehyde or formate. Synthesis of the 3-acetoxymethyl analogwas unsuccessful. Biologically active 1-oxacephems were derived from by known processes. 相似文献
74.
75.
Biodegradable elastomeric network polyesters were prepared from multifunctional aliphatic carboxylic acids such as tricarballylic acid (Yt) or meso-1,2,3,4-butanetetracarboxylic acid (Xb) and poly(epsilon-caprolactone) (PCL) diols with molecular weights of 530, 1,250 and 2,000 g.mol-1. Prepolymers prepared by a melt polycondensation were cast from DMF solution and postpolymerized at 280 degrees C for various periods of times to form a network. The resultant films were transparent, flexible and insoluble in organic solvents. The network polyesters obtained were characterized by IR absorption spectra, WAXS, density measurement, DSC, and tensile test. YtPCL1250, and XbPCL1250 network polyester films showed good elastomeric properties with high ultimate elongation (540-590%), and low Young's modulus (2.5-3.3 MPa). The enzymatic degradation was estimated by the weight loss of network films in a buffer solution with Rhizopus delemar lipase at 37 degrees C. The degree and rate of degradation were significantly affected by the molecular weight of PCL diol, chemical structures of multifunctional aliphatic carboxylic acids and the morphology of network films. The changes in the solid states of network films during the degradation were also estimated by the results of DSC and WAXS. [see text] 相似文献
76.
Masahito Katto Hironari Zushi Wataru Nagaya Shinya Harano Ryota Matsumoto Atushi Yokotani Masanori Kaku Shoichi Kubodera Noriaki Miyanaga 《Applied Physics A: Materials Science & Processing》2010,101(2):297-301
We have developed intense vacuum ultraviolet (VUV) radiation sources for advanced material processing, such as photochemical
surface reactions and precise processing on a nanometer scale. We have constructed a new VUV laser system to generate sub-picosecond
pulses at the wavelength of 126 nm. A seed VUV pulse was generated in Xe as the 7th harmonic of a 882-nm Ti:sapphire laser.
The optimum conversion was achieved at the pressure of 1.2 Torr. The seed pulse will be amplified by the Ar2*\mathrm{Ar}_{2}^{*} media generated by an optical-field-induced ionization Ar plasma produced by the Ti:sapphire laser. We have obtained a gain
coefficient of g=0.16 cm−1. Our developing system will provide VUV ultra-short pulses with sub-μJ energy at a repetition rate of 1 kHz. 相似文献
77.
Wataru Higemoto Kanetada Nagamine Shinji Kuroda Koki Takita 《Molecular Crystals and Liquid Crystals》2013,570(2):51-56
Abstract The microscopic state of the positively charged light particle in the transition metal dichalcogenide 2H-NbSe2 was studied using the muon spin relaxation method (μ+SR) and muon level crossing resonance method (μ-LCR). Muons are expected to stay at interlayer position and behaves as a hydrogen like intercalant. We discuss the relation between conduction electron properties and the muon's behavior. 相似文献
78.
Eduardo Viegas Misako Takayasu Wataru Miura Koutarou Tamura Takaaki Ohnishi Hideki Takayasu Henrik Jeldtoft Jensen 《Complexity》2013,19(1):22-36
The world economy consists of highly interconnected and interdependent commercial and financial networks. Here, we develop temporal and structural network tools to analyze the state of the economy and the financial markets. Our analysis indicates that a strong clustering can be a warning sign. Reduction in diversity, which was an essential aspect of the dynamics surrounding the financial markets crisis of 2008, is seen as a key emergent feature arising naturally from the evolutionary and adaptive dynamics inherent to the financial markets. Similarly, collusion amongst construction firms in a number of regions in Japan in the 2000s can be identified with the formation of clusters of anomalous highly connected companies. © 2013 Wiley Periodicals, Inc. Complexity 19: 22–36, 2013 相似文献
79.
The aim of the present study was to form a nitride layer on a titanium (Ti) substrate through a compact laser-nitriding system comprising a focused pulsed Nd:YAG laser and nitrogen gas blow. To obtain a high-quality layer, the effects of pulse frequency and gas flow rate on the surface characteristics were investigated by using plasma emission analysis as well as X-ray analyses. Optical emission spectra from the laser-induced plasma mainly consisted of ionic Ti lines, and their intensities when the pulse frequency was 15 Hz were much higher than those for 8 Hz. Similarly, the reflections from the δ-TiN phase in the X-ray diffraction (XRD) pattern were enhanced when using 15 Hz. On the other hand, the flow rate of nitrogen gas blow had a significant effect on the thickness of the thin oxide layer that formed above the nitride layer. Using a lower flow rate resulted in the formation of a thicker oxide layer. The higher pulse frequency and the faster flow rate were beneficial for obtaining a higher-quality layer because of the enhancement of nitridation and the suppression of oxidation, respectively. 相似文献
80.
Yoshida Go Ninomiya Kazuhiko Inagaki Makoto Higemoto Wataru Strasser Patrick Kawamura Naritoshi Shimomura Koichiro Miyake Yasuhiro Miura Taichi Kubo Kenya M. Shinohara Atsushi 《Journal of Radioanalytical and Nuclear Chemistry》2019,320(2):283-289
The role of valence electrons for the muon capture process by molecules is experimentally investigated with the aid of cascade calculations. Low-momentum muons are introduced to gas targets of CO, CO2, and COS below atmospheric pressure. The initial states of captured muons are determined from the measured muonic X-ray structure of the Lyman and Balmer series. We propose that the lone pair electrons in the carbon atom of CO significantly contribute to the capture of a muon with large angular momenta.
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