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71.
72.
[4+1] Cycloaddition reaction between isocyanides and N-acylimine derivatives generated from N-acyl N,O-acetals acting as isocyanophiles has been developed. These reactions proceeded smoothly and cleanly to afford the corresponding 5-aminooxazoles in high yields. This reaction was extended to the syntheses of 5-aminothiazoles by using N-thioacyl N,O-acetals. A wide range of N-acyl N,O-acetals, N-thioacyl N,O-acetals, and isocyanides were found to be applicable to this reaction. 相似文献
73.
Keiichi Tomishige Masazumi Tamura Yoshinao Nakagawa 《Chemical record (New York, N.Y.)》2014,14(6):1041-1054
The catalytic performance of ReOx‐modified Ir metal catalyst in the hydrogenolysis of C–O bonds is strongly dependent on the choice of solvent. The acidic property of the Re species becomes obvious in the alkane solvent, and the hydrogenolysis reaction proceeds mainly by acid‐catalyzed dehydration and the subsequent metal‐catalyzed hydrogenation. The acidic property of the Re species is weakened in water; however, the hydrogenolysis reaction proceeds in water via a direct mechanism involving SN2‐like attack of a hydride species at the interface between Ir and ReOx on the adsorbed Re alkoxide species. This mechanism enabled the selective dissociation of the C–O bond neighboring the CH2OH group. 相似文献
74.
Solubility of several anthraquinone derivatives in supercritical carbon dioxide was readily available in the literature, but correcting ability of the existing models was poor. Therefore, in this work, two new models have been developed for better correlation based on solid–liquid phase equilibria. The new model has five adjustable parameters correlating the solubility isotherms as a function of temperature. The accuracy of the proposed models was evaluated by correlating 25 binary systems. The proposed models observed provide the best overall correlations. The overall deviation between the experimental and the correlated results was less than 11.46% in averaged absolute relative deviation (AARD). Moreover, exiting solubility models were also evaluated for all the compounds for the comparison purpose. 相似文献
75.
Observation of insulating–insulating monoclinic structural transition in macro‐sized VO2 single crystals [Phys. Status Solidi RRL 5, No. 3, R107–R109 (2011)] 下载免费PDF全文
Bongjin Simon Mun Kai Chen Youngchul Leem Catherine Dejoie Nobumichi Tamura Martin Kunz Zhi Liu Michael E. Grass Changwoo Park Joonseok Yoon Y. Yvette Lee Honglyoul Ju 《固体物理学:研究快报》2015,9(3):206-206
In our article, we reported the observation of monoclinic M2 to M1 structural phase transition in VO2 single crystal near the temperature of ~49 °C. However, the re‐examination of Laue patterns reveals that previously defined monoclinic M1 and M2 phases can be interpreted as monoclinic M2 and triclinic T phases instead. Careful experimental geometry calibration and further refinement of the lattice parameter ratios and angles show that monoclinic M2 and triclinic T phases fit better with the experimental data. On the other hand, our previous misidentification of the insulating phases does NOT affect the conclusions of our article. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
76.
Bongjin Simon Mun Joonseok Yoon Sung-Kwan Mo Kai Chen Nobumichi Tamura Catherine Dejoie 《Phase Transitions》2013,86(10):941-946
The metal insulator transition (MIT) characteristics of macro-size single-domain VO2 crystal were investigated. At the MIT, the VO2 crystal exhibited a rectangular shape hysteresis curve, a large change in resistance between the insulating and the metallic phases, in the order of ~105, and a small transition width (i.e. temperature difference before and after MIT) as small as 10?3°C. These MIT characteristics of the VO2 crystals are discussed in terms of phase boundary motion and the possibility of controlling the speed of the phase boundary, with change in size of crystal, is suggested. 相似文献
77.
It is shown that timing jitter owing to the Gordon-Haus (G-H) effect of solitons that are compressed adiabatically in dispersion-decreasing fibers (DDF's) is approximately determined by total dispersion and initial conditions, which are independent of compression dynamics. As a result the established theory for G-H jitter is still applicable. Timing jitter near the levels predicted by theory is observed in pulses from a regeneratively mode-locked fiber laser compressed in a DDF. 相似文献
78.
Ultrashort-pulse fiber ring lasers 总被引:4,自引:0,他引:4
L.E. Nelson D.J. Jones K. Tamura H.A. Haus E.P. Ippen 《Applied physics. B, Lasers and optics》1997,65(2):277-294
Received: 18 February 1997/Revised version: 22 April 1997 相似文献
79.
Akikawa H Ajimura S Chrien RE Eugenio PM Franklin GB Franz J Gang L Imai K Khaustov P May M Pile PH Quinn B Rusek A Sasao J Sawafta RI Schmitt H Tamura H Tang L Tanida K Yuan L Zhou SH Zhu LH Zhu XF 《Physical review letters》2002,88(8):082501
With a germanium detector array (Hyperball), we observed two gamma-ray peaks corresponding to the two transitions (5/2(+)-->1/2(+) and 3/2(+)-->1/2(+)) in the (9)(Lambda)Be hypernucleus which was produced by the 9Be(K-,pi(-)) reaction. The energies of the gamma rays are 3029 +/- 2 +/- 1 keV and 3060 +/- 2 +/- 1 keV. The energy difference was measured to be 31.4(+2.5)(-3.6) keV, which indicates a very small Lambda-spin-dependent spin-orbit force between a Lambda and a nucleon. This is the smallest level splitting by far ever measured in a hypernucleus. 相似文献
80.
In this paper, we introduced a method to measure grain rotation of nanomaterials under external stress using a high pressure diamond anvil cell and the Laue microdiffraction technique at a synchrotron facility. We used tungsten carbide marker crystals to investigate grain rotation activities of 3 and 500?nm nickel media. Our results show that the grain rotation of 3 and 500?nm nickel nanocrystals increase with pressure and finally rotation of 500?nm nickel tends to stop at a lower pressure/stress level than 3?nm nickel. 3?nm nickel nanocrystals show a higher rotation magnitude than 500?nm nickel nanocrystals. Our measurements show an effective method to study the grain rotation of nanomaterials especially in ultrafine nanocrystals. 相似文献