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51.
An electron spin resonance experiment has been performed on the Cr-rich concentrations of the random mixture Rb2Mn(1-x)CrxCl4 of an insulating ferromagnet (Rb2CrCl4) and an insulating antiferromagnet (Rb2MnCl4). The resonance fields in x = 0.6, 0.7 and 0.8 samples begin to shift towards low field side at temperatures well above the Curie temperatures, when the external field is applied in the c-plane of the crystal. The shift of the resonance field with temperature of the x = 0.7 sample agreed well with that of the x = 0.8 sample, after scaling the temperature axis, while the shift in the x = 0.6 crystal did not. From this observation, we argue that the x = 0.7 and x = 0.8 samples have a long-range ordered ferromagnetic phase below Tc, and that the low temperature phase of the x = 0.6 sample is not a truely long-range ordered one. A weak resonance line was observed in the x = 0.8 sample below about 20 K. This resonance is discussed in connection with the re-entrant spin-glass behavior of this mixed system found in the ac susceptibility measurement. 相似文献
52.
Mitsutoshi Tanimoto Shuji Saito Yasuki Endo Eizi Hirota 《Journal of Molecular Spectroscopy》1983,100(1):205-211
The microwave spectrum of the SiF radical was observed in both and of the ground vibronic state. The SiF radical was produced by a dc discharge either in a mixture or in a transient molecule SiF2 generated by the reaction of SiF4 with heated solid silicon. The latter gave twice as intense a spectrum. A least-squares fit to the observed spectrum showed the rotational constant and the centrifugal distortion constant to be 17 350.2752(63) and 0.03188(13) MHz, respectively, with three standard errors in parentheses applying to the last digits of the constants. The lambda-doubling parameter p0 was found to be negative, ?87.67 MHz, indicating that the 2Σ+ excited state contributions dominate over those of 2Σ?. All four hyperfine coupling constants a, b, c, and d were determined and were employed to discuss the unpaired-electron spin and orbital distributions in the SiF radical. 相似文献
53.
The influence of a static magnetic field on the instability of plastic flow (the Portevin-Le Chatelier effect) is revealed in NaCl: Eu quenched crystals. It is found that, in an external magnetic field, the yield stress of the crystals is reduced, the probability of plastic strain jumps and their amplitude decrease, and the amplitude distribution of the plastic strain jumps becomes random. The number of shear bands formed on the surface of crystals strained in the magnetic field is halved as compared to that observed without a magnetic field. 相似文献
54.
Hisahiro Nakayama Jiro Kasahara Akiko Matsuo Ikkoh Funaki 《Proceedings of the Combustion Institute》2013,34(2):1939-1947
The propagation of curved detonation waves of gaseous explosives stabilized in rectangular-cross-section curved channels is investigated. Three types of stoichiometric test gases, C2H4 + 3O2, 2H2 + O2, and 2C2H2 + 5O2 + 7Ar, are evaluated. The ratio of the inner radius of the curved channel (ri) to the normal detonation cell width (λ) is an important factor in stabilizing curved detonation waves. The lower boundary of stabilization is around ri/λ = 23, regardless of the test gas. The stabilized curved detonation waves eventually attain a specific curved shape as they propagate through the curved channels. The specific curved shapes of stabilized curved detonation waves are approximately formulated, and the normal detonation velocity (Dn)?curvature (κ) relations are evaluated. The Dn nondimensionalized by the Chapman–Jouguet (CJ) detonation velocity (DCJ) is a function of the κ nondimensionalized by λ. The Dn/DCJ?λκ relation does not depend on the type of test gas. The propagation behavior of the stabilized curved detonation waves is controlled by the Dn/DCJ?λκ relation. Due to this propagation characteristic, the fully-developed, stabilized curved detonation waves propagate through the curved channels while maintaining a specific curved shape with a constant angular velocity. Self-similarity is seen in the front shock shapes of the stabilized curved detonation waves with the same ri/λ, regardless of the curved channel and test gas. 相似文献
55.
Akiko Takeda Katsuki Fujisawa Yusuke Fukaya Masakazu Kojima 《Journal of Global Optimization》2002,24(2):237-260
As computing resources continue to improve, global solutions for larger size quadrically constrained optimization problems become more achievable. In this paper, we focus on larger size problems and get accurate bounds for optimal values of such problems with the successive use of SDP relaxations on a parallel computing system called Ninf (Network-based Information Library for high performance computing). 相似文献
56.
Akiko Hashimoto Takehiro Yamanaka Takeji Takamura-Enya 《Journal of nanoparticle research》2017,19(12):402
Fullerene is a well-known carbon nanomaterial, which can be potentially used for drug manufacture or delivery. Despite several successful examples of utilizing fullerene derivatives as drug candidate materials, their low water solubility under physiological conditions negatively affects the cell penetration efficiency after treatment. In this work, we successfully synthesized two fullerene derivatives with covalently attached fluorescein and boron dipyrromethene (BODIPY) fluorophore moieties, which exhibited cellular uptake and intracellular localization. While both fluorophores decreased their fluorescence intensity in the vicinity of fullerene, the cellar uptake of the fluorescein-modified fullerene was detected via fluorescence microscopy observations. Moreover, decreases in the fluorescence intensities of the intact fluorescein and BODIPY species were observed when both fluorophores and fullerene coexisted in aqueous media. 相似文献
57.
Uchiyama N Matsunaga K Kiuchi F Honda G Tsubouchi A Nakajima-Shimada J Aoki T 《Chemical & pharmaceutical bulletin》2002,50(11):1514-1516
Trypanocidal constituents of dried leaves of Laurus nobilis L. (Lauraceae) were examined. Activity-guided fractionation of the methanol extract resulted in the isolation of two guaianolides, dehydrocostus lactone (1) and zaluzanin D (2), and a new p-menthane hydroperoxide, (1R,4S)-1-hydroperoxy-p-menth-2-en-8-ol acetate (3). The minimum lethal concentrations of these compounds against epimastigotes of Trypanosoma cruzi were 6.3, 2.5, and 1.4 microM, respectively. 相似文献
58.
Haino T Araki H Fujiwara Y Tanimoto Y Fukazawa Y 《Chemical communications (Cambridge, England)》2002,(18):2148-2149
A new class of fullerene sensors based on calix[5]arenes has produced the highly sensitive detection of C60 and C70. 相似文献
59.
We study the correlation between CP violation in neutrino oscillations and leptogenesis in the framework with two heavy Majorana neutrinos and three light neutrinos. Among three unremovable CP phases, a heavy Majorana phase contributes to leptogenesis. We show how the heavy Majorana phase contributes to Jarlskog determinant J as well as neutrinoless double beta decay by identifying a low energy CP-violating phase which signals the CP-violating phase for leptogenesis. For some specific cases of the Dirac mass term of neutrinos, a direct relation between lepton number asymmetry and J is obtained. We also study the effect coming from the phases which are not related to leptogenesis. 相似文献
60.
Electron spin resonance experiments at submillimeter and millimeter wavelengths have been performed on the random mixture, Rb2Mn(1-x)CrxCl4 of an insulating antiferromagnet Rb2MnCl4 and an insulating ferromagnet Rb2CrCl4. From the antiferromagnet resonance in the Mn-rich concentrations, the antiferromagnetic exchange field is shown to become small with Cr concentration. Thus, a competition between the antiferromagnetic and ferromagnetic exchange interactions really exists in this mixed system.A competition of the uniaxial anisotropy of Rb2MnCl4 with the planar one of Rb2CrCl4 has also been found. 相似文献