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71.
关于局部对称空间中2-调和子流形 总被引:6,自引:0,他引:6
本文研究局部对称完备黎曼流形中的紧致2-调和子流形,得到了这类流形第二基本模式长平方的Pinching定理及推广的J.Simons型积分不等式。 相似文献
72.
The object of the present investigation is to introduce a new trigonometric method of summation which is both regular and
Fourier effective and determine its status with reference to other methods of summation (see §2-§4) and also give an application
of this method to determine the degree of approximation in a new Banach space of functions conceived as a generalized Holder
metric (see §5). 相似文献
73.
The nanocrystal samples of titanium dioxide doped with europium ion (Eu3+/TiO2 nanocrystal) are synthesized by the sol-gel method with hydrothermal treatment. The Eu3+ contents (molar ratio) in the samples are 0, 0.5%, 1%, 2%, 3% and 4%. The X-ray diffraction, UV-Vis spectroscopy data and scanning electron microscope image show that crystallite size is reduced by the doping of Eu3+ into TiO2. Comparing the Raman spectra of TiO2 with Eu3+/TiO2 (molar ratio Eu3+/TiO2=1%, 2% and 4%) nanocrystals at different annealing temperatures indicates that the anatase-to-rutile phase transformation temperatures of Eu3+/TiO2 nanocrystals are higher than that of TiO2. This is due to the formation of Eu-O-Ti bonds on the surface of the TiO2 crystallite, as characterized by the X-ray photoelectron spectroscopy. The photoluminescence spectra of TiO2 in Eu3+/TiO2 nanocrystals are interpreted by the surface self-trapped and defect-trapped exciton relaxation. The photoluminescence of Eu3+ in Eu3+/TiO2 nanocrystals has the strongest emission intensity at 2% of Eu3+ concentration. 相似文献
74.
Tatsuo Nakagawa Satoshi Fukura Munenori Nakai Kazumasa Sugiyama Ryohei Kokawa Hiroyuki Kagi 《Optical Review》2006,13(4):269-275
We constructed a scanning near-field optical microscope (SNOM) on a commercially available atomic force microscopy (AFM) apparatus
(SPM-9500J2; Shimadzu Corp.) to measure the stress distribution in ceramic composite materials. Features of our SNOM system
are: (1) a compact SNOM head substituted for the original AFM head; (2) a wide scanning range (125 × 125 μm2) inherited from the original scanner; (3) use of conventional shear-force regulation; (4) an optical system for the illumination-collection
(I-C) mode; (5) excitation by a 488 nm line of an Ar-ion laser, and (6) light detection by photon counting or a polychromator
equipped with an electronically cooled charge coupled device (CCD). This SNOM system was used to measure the surface structure
and stress distribution of an Al2O3/ZrO2 eutectic composite. We simultaneously measured topographic images and fluorescence spectra of an Al2O3/ZrO2 eutectic composite. We estimated its peak intensity, peak position, and peak width from the fluorescence spectrum during
scanning, which respectively correspond to the abundance of Al2O3, stress in the grain, and the anisotropy of that stress. Mapping images showed that the stress and its anisotropy were weaker
in the center of the Al2O3 grain than its boundary between Al2O3 and ZrO2. That observation suggests that Al2O3 underwent intense anisotropic stress induced by volume expansion in the phase transition of ZrO2 from the cubic phase to the monoclinic phase during preparation. 相似文献
75.
76.
Yi-Shiue Lin 《Applied Surface Science》2006,252(16):5892-5899
Dissociative adsorption of CCl4 on TiO2 at 35 °C has been studied by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and electron spin resonance. CCl4 decompose to form CO, CO2, and CO3 on the surface, at such a low temperature, in which CO2 formation is not from CO oxidation on TiO2, but CO3 can be produced by CO and CO2 adsorption. The Cl generated from CCl4 decomposition is left on the surface and bonded to titanium ions. Mineralization of CCl4 on TiO2 involves the lattice oxygens. Thermodynamical driving force and possible reaction routes for CO and CO2 formation in the CCl4 decomposition on TiO2 are discussed. 相似文献
77.
V. N. Sorokoumov S. N. Morozkina I. A. Balova 《Chemistry of Heterocyclic Compounds》2006,42(5):615-624
An investigation of the reaction of 1-lithio-1,3-diynes, generated in situ, with nitriles has been carried out. In the case
of aromatic nitriles 1-arylalk-1-ene-3,5-diynylamines are formed, which undergo dimerization and cyclization on isolation,
giving 3-(alka-1,3-diynyl)-4-(alk-2-ynyl)-2,6-diarylpyridines. The effect of the nature of the substituent in the benzonitrile
molecule on the selectivity of the reaction and the yield of the products has been determined. A scheme is proposed for the
conversions and the structures of the intermediates have been established.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 701–710, May, 2006. 相似文献
78.
Characterization of iron surface modified by 2-mercaptobenzothiazole self-assembled monolayers 总被引:1,自引:0,他引:1
A self-assembled monolayer of 2-mercaptobenzothiazole (MBT) adsorbed on the iron surface was prepared. The films were characterized by electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared reflection spectroscopy (FT-IR) and scanning electron microscopy (SEM). Besides, the microcalorimetry method was utilized to study the self-assembled process on iron surface and the adsorption mechanism was discussed from the power-time curve. The results indicated that MBT was able to form a film spontaneously on iron surface and the presence of it could protect iron from corrosion effectively. However, the assembling time and the concentration influence the protection efficiency. Quantum chemical calculations, according to which adsorption mechanism was discussed, could explain the experimental results to some extent. 相似文献
79.
Summary The gas chromatographic behaviour of crosslinked macroporous 2-hydroxyethyl methacrylate grafted with 2-methyloxazoline was
investigated and the range of applicability of the copolymer was assessed. Retention index values were measured on this copolymer
and compared with those obtained on the terpolymer 2-hydroxyethyl methacrylate-ethylene dimethacrylate-acrylonitrile. Rohrschneider
constants and efficiency data for selected sorbates are given. The use of this type of polymer in the separation of various
types of compounds is documented by various examples. 相似文献
80.
Precise measurement of magnetic moment of short-lived β-emitting nuclei12B ( I π=1+, T 1/2=20.18 ms)
Zhou Dongmei Zheng Yongnan Du Enpeng Xu Yongjun Zhu Jiazheng Yuan Daqing Wang Zhiqiang Luo Hailong Zuo Yi Ma Ruigang Duan Xiao M. Mihara M. Fukuda K. Matsuta T. Minamisono Zhu Shengyun 《中国科学G辑(英文版)》2004,47(5):531-539
The spin polarized β-emitting nuclei12B (I
π=1+,T
1/2=20.18 ms) were produced by the nuclear reaction11B(d, p)12B and by the selection technique of the incident deuteron energy and the12B recoil angle following the nuclear reaction. The nuclear magnetic moment of the short-lived nuclei12B was measured by β-NMR with the β-NMR and β-NQR setup established for the first time in China. The nuclear magnetic moment
of12B was determined to be μ=0.99993±0.00048 nm org=0.99993±0.00048 after the precise correction of the Knight shift. 相似文献