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321.
Chiral properties of Wilson fermions at finite temperature are investigated by numerical methods. We show that when the quark mass is properly defined, for a given β and K (hopping parameter), its value is independent of whether the system is in the high-temperature phase or in the low-temperature phase. The temperature dependence of the pion screening mass at the chiral limit where the quark mass vanishes is consistent with the physical picture that the spontaneously broken chiral symmetry is recovered at T = Tc. 相似文献
322.
Tryptophan was rapidly transferred from 1H2O into a 2H2O medium by a stopped-flow device, and a time-dependent fluorescence increase was traced. It has been shown that this fluorescence change is caused by the deuteration of the α-ammonium (—NH+3) group. 相似文献
323.
M. Tsuboi J. Inatani T. Kasuga R. Kawabe A. Sakamoto H. Iwashita K. Miyazawa 《International Journal of Infrared and Millimeter Waves》1987,8(1):1-11
A 40 GHz band SIS mixer receiver has been built using Nb/Al–AlOx/Nb array junctions and a 4.3 K closed cycle helium refrigerator. The minimum conversion loss of the mixer is 2±1 dB and the single sideband receiver noise temperature (TRX (SSB)) is as low as 110±10 K at 36 GHz. TRX (SSB) is almost constant in the IF bandwidth of 600 MHz. The mixer saturation level is as high as 15 nW, which is comparable to the injected LO power.Nobeyama Radio Observatory (NRO), a branch of the Tokyo Astronomical Observatory, University of Tokyo, is a cosmic radio observing facility open for outside users. 相似文献
324.
Yoshiaki Hamada Masamichi Tsuboi Takahiro Matsuzawa Kaoru Yamanouchi Kozo Kuchitsu Yoshihiro Koga Shigeo Kondo 《Journal of Molecular Spectroscopy》1984,105(2):453-464
Infrared absorption spectrum of allylimine in the gas phase was measured for the first time. The spectrum consisted of two rotational isomers, cis and trans, around the CC bond. The relative population of the trans form was 70–80%, and the rest was for the cis form at room temperature. This intermediate molecule was produced by the thermal decomposition of diallylamine and by the isomerization of propargylamine. The vibrational assignments were made with the help of an ab initio MO calculation. The half-life in the absorption cell was about 20 min. 相似文献
325.
Masahide Shimokawabe Nozomu Takahata Takehiro Chaki Nobutsune Takezawa 《Reaction Kinetics and Catalysis Letters》2000,71(2):313-318
Pronounced activities on the reduction of N2O with CH4 were observed over Fe-ZSM-5, Pd-ZSM-5, and Pt-ZSM-5 catalysts, respectively. No significant deactivation has been detected over Fe-ZSM-5 in the presence of oxygen. 相似文献
326.
Numerical study on spinning detonations 总被引:4,自引:0,他引:4
Spinning detonations in both a circular tube and a square tube are presented in order to reveal characteristics of spinning modes by using three-dimensional simulations with a detailed chemical reaction model. The present results show a feature of a single spinning detonation which was discovered in 1926. The shock patterns in both cases are similar except the pressure trail, however, the shock wave angles and the shock wave lengths are shown to be dependent on the cross section configuration of the tube. The pitch angle, the track angle, the Mach stem angle, and the incident shock angle on the tube wall in the numerical results agree well with those in the experimental ones, and they are independent of the compositions of mixture, tube diameters, and initial pressures. 相似文献
327.
Tsuchii K Tsuboi Y Kawaguchi S Takahashi J Sonoda N Nomoto A Ogawa A 《The Journal of organic chemistry》2007,72(2):415-423
A highly selective method for introducing thio and seleno groups into a variety of isocyanides has been developed based on the elucidation of the relative reactivities of organic dichalcogenides and chalcogen-centered free radicals. When the reactions of aromatic isocyanides (ArNC) with organic disulfides (R'SSR') and diselenides (R'SeSeR') are conducted upon irradiation with a tungsten lamp through Pyrex (hnu>300 nm), simultaneous introduction of both thio and seleno groups into the isocyanides takes place to provide the corresponding thioselenation products (R'S-C(=NAr)-SeR') in good yields with excellent selectivity. In the cases of aliphatic isocyanides (RCN), a novel diselenide-assisted bisthiolation of RNC with diaryl disulfides (Ar'SSAr') proceeds successfully to give the corresponding bisthiolation products (Ar'S-C(=NR)-SAr'), although the same photoirradiated reaction of RNC with diaryl disulfides does not occur in the absence of diselenide. These double chalcogenation reactions are assumed to proceed via the formation of imidoyl radical intermediates by the reaction of isocyanides with relatively reactive thio radicals (compared with seleno radicals). The obtained thioselenation products can be employed as useful precursors for the construction of beta-lactam framework by the formal [2+2] cyclization with ketene equivalents. 相似文献
328.
Tada M Ishiguro N Uruga T Tanida H Terada Y Nagamatsu S Iwasawa Y Ohkoshi S 《Physical chemistry chemical physics : PCCP》2011,13(33):14910-14913
μ-XAFS analysis using an X-ray μ-beam (1000 nm (h) × 800 nm (v)) was successfully carried out on a single particle of a practical catalyst NiO(x)/Ce(2)Zr(2)O(y) (0 ≤x≤ 1, 7 ≤y≤ 8). The oxidation state and local coordination structure of the NiO(x)/Ce(2)Zr(2)O(y) particle were characterized by Ni K-edge μ-XANES and μ-EXAFS, which showed the catalytically active and inactive phases of a single catalyst particle. 相似文献
329.
By measuring the emission spectra and the fluorescence lifetime of the 4 I 13 /2 state of Er 3+ ions in Gd 2 SiO 5 crystal at different temperatures,the effects of temperature on the spectra and the lifetime of the 4 I 13 /2 state are investigated. When the temperature increases,the emission line width for the 4 I 13 /2 → 4 I 15 /2 transition is broadened,and the main emission lines at 1 596,1 609,and 1 644 nm shifte toward shorter wavelengths. The measured lifetime of the 4 I 13 /2 state decreases from 13.2 to 8.4 ms with temperature increase from 13 to 300 K,which is mainly due to the temperature dependence of multiphonon relaxation between the 4 I 13 /2 and 4 I 15 /2 states and the changing population distribution among the Stark levels within the 4 I 13 /2 state. The experimental results imply that low temperature condition is better for the ~1.6-μm laser output. 相似文献
330.
Konosu Y Matsumoto H Tsuboi K Minagawa M Tanioka A 《Langmuir : the ACS journal of surfaces and colloids》2011,27(24):14716-14720
This letter reports the enhancing effects of a nanofiber network structure on stimuli-responsive wettability switching. Thermoresponsive coatings composed of nanofibers were prepared by electrospinning from thermoresponsive polymer poly(N-isopropylacrylamide) (PNIPAAm). The nanofiber coatings showed a large amplitude of thermoresponsive change in the wettability from hydrophilic to hydrophobic states compared to a smooth cast film. In particular, the combination of the surface chemistry and unique topology of the electrospun nanofiber coatings enables a transition from the Wenzel state to the metastable Cassie-Baxter state with an increase in temperature and consequently an enhanced amplitude of change in the water contact angles: the apparent contact angle differences between 25 and 50 °C are Δθ*(25-50?°C?)= 108 and 10° for the nanofiber coatings with a diameter of 830 nm and a smooth cast film, respectively. The fabrication of the 3D nanofiber network structure by electrospinning from stimuli-responsive materials is a promising option for highly responsive surfaces in wettability. 相似文献