排序方式: 共有30条查询结果,搜索用时 31 毫秒
1.
MASAKATSU SAEKI SHIN-ICHI OHNO ENZO TACHIKAWA NAOTO AZUMA TETSUO MIYAZAKI KENJI FUEKI 《Journal of the American Ceramic Society》1985,68(3):151-155
Behavior of deuterium atoms in fused silica, which were implanted by 80-keV D+ (D2 + , D3 + ) ions or doped thermally by D2 (or D2 O), was studied by infrared Fourier transform spectroscopy (FTIR) and by ESR spectroscopy. When 80-keV deuteron ions are implanted into fused silica, OD bonds are formed. The OD bonds are also formed by thermal doping with D2 or D2 O. When the deuterated silica is γ-ray irradiated at 77 K, D atoms are formed by rupture of the OD bonds. The efficiency of the OD bond rupture in the deuteron-implanted silica is much less than that in the D2 -doped silica. It is concluded from the results of thermal annealing that the low efficiency of the OD bond rupture in the deuteron-implanted silica is due to the radiation damage accompanying the implantation process. However, the decay rate and detrapping energy of deuterium atoms, once formed in the silica, are similar in both cases. 相似文献
2.
SHIN-ICHI IWAI TAKASHI WATANABE ICHIRO MINATO KIYOSHI OKADA† HIDEKI MORIKAWA 《Journal of the American Ceramic Society》1980,63(1-2):44-46
Thermal decomposition of mullite into corundum was investigated using a high-temperature X-ray single-crystal camera equipped with a gas-flame furnace and by scanning electron microscopy and electron probe microanalysis (EPMA). When heated to ∼1750°C, mullite decomposed to corundum by the liberation of the SiO2 component with topotaxial relations of:
Thus, it was considered that, when mullite decomposed into corundum, their oxygen close-packed planes were almost preserved. The SEM photographs showed that the crystals of the developed corundum are prismatic and ∼5 μm wide. The EPMA showed that the phase boundary between mullite and developed corundum is discontinuous. 相似文献
- (1)
(310)
mull ∥(001)cor ; [001]mull ∥[110]cor - (2)
(130)
mull ∥(001)cor ; [001]mull ∥[110]cor - (3)
(110)
mull ∥(001)cor ; [001]mull ∥[110]cor
Thus, it was considered that, when mullite decomposed into corundum, their oxygen close-packed planes were almost preserved. The SEM photographs showed that the crystals of the developed corundum are prismatic and ∼5 μm wide. The EPMA showed that the phase boundary between mullite and developed corundum is discontinuous. 相似文献
3.
4.
NAOTO AZUMA TETSUO MIYAZAKI KENJI FUEKI ISAO SAKAGUCHI SHIN-ICHI HIRANO 《Journal of the American Ceramic Society》1986,69(1):19-22
Cleavage of the O–H bond in quartz was studied by Fourier transform infrared spectroscopy and ESR spectroscopy. When quartz single crystals and fused silica glass are γ-irradiated at 77 K, hydrogen atoms are produced by rupture of O–H bonds. The initial efficiency of O–H bond cleavage in quartz single crystals, i.e. the initial yield of H atoms, was three times as great as that in fused silica glass, although the concentration of O–H bonds in quartz single crystals (70 ppm) is much lower than that in fused silica glass (4000 ppm). The efficiency of O–H bond cleavage in quartz single crystals indicates that energy transfer from the irradiated single crystal to the O–H bonds takes place effectively at 77 K. The efficiency of O–H bond cleavage decreases with increasing γ-ray dose, i.e. with increasing amounts of radiation-induced defects in quartz single crystals. When the radiation-induced defects are removed by annealing the irradiated quartz single crystal at 773 K, the O–H bonds are ruptured again as effectively as for a fresh quartz single crystal. The distance of the energy transfer, estimated by a target model, is ∼15 nm. 相似文献
5.
SHIN-ICHI SHIRASAKI KOICHIRO TAKAHASHI KAZUYUKI KAKEGAWA 《Journal of the American Ceramic Society》1973,56(8):430-435
A series of lead titanates containing lattice defects was prepared and characterized in terms of inhomogeneously distributed vacancies, □Pb and □O• . The tetragonal lattice strain and the Curie temperature varied as functions of the Pb or O deficiency in the crystals. The tetragonal strain for these crystals decreased slowly with increasing temperature as the Curie temperature was approached. The phase transition, which extends over a temperature interval, is interpreted according to a model in which microregions in the crystal differ in composition and therefore have different Curie temperatures. 相似文献
6.
Quantitative representation of complicated behavior of fluid mixtures in the critical region by any of equation-of-state theories remains as a difficults thermodynamic topics to date.In the present work,a computational efforts were made for representing various types of critical loci of binary water with hydrocarbon systems showing Type Ⅱ and Type Ⅲ phase behavior by an elementary equation of state[called multi-fluid nonrandom lattice fluid EOS(MF-NLF EOS)]based on the lattice statistical mechanical theory.The model EOS requires two molecular parameters which representing molecular size and interaction energy for a pure component and single adjustable interaction energy parameter for binary mixtures.Critical temperature and pressure data were used to obtain molecular size parameter and vapor pressure data were used to obtain interaction energy parameter.The MF-NLF EOS model adapted in the present study correlated quantitatively well the critical loci of various binary water with hydrocarbon systems. 相似文献
7.
HIDEKI MORIKAWA SHIN-ICHI MIWA MICHIHIRO MIYAKE FUMIYUKI MARUMO TOSHIYUKI SATA 《Journal of the American Ceramic Society》1982,65(2):78-81
The structure of SiO2 -Al2 O3 glasses with up to 60 wt% Al2 O3 was investigated using the radial distribution function together with the correlation method based on X-ray scattering intensity data. Radial distribution curves are interpreted on the basis of glass-in-glass separation with the constituents of SiO2 -rich and Al2 O3 -rich glasses. The structure of the Al2 O3 -rich glass has a short-range ordering similar to the crystal structure of mullite. The calculated S- i (S) curve of this model gives good agreement with the observed one. 相似文献
8.
9.
This paper is concerned with the problem of determining eigenvalues, retained in Marshall's reduced order model, which have the largest effect on the retaining state vector or give the best approximate reduced system in the sense of ISE criterion. The main objective is to show that the usual choice of eigenvalues in Marshall's model reduction technique (decomposition of eigenvalues into fast modes and slow modes) does not necessarily give a well approximated reduced order model. Here the measure of approximation is defined and calculated by means of ISE criterion. The effectiveness of this method is explained by two illustrative examples. 相似文献
10.
Miyaji F Iwai M Kokubo T Nakamura T 《Journal of materials science. Materials in medicine》1998,9(2):61-65
It has been confirmed that the apatite nucleation is induced by silanol (Si–OH) groups formed on the surfaces of materials and/or silicate ions adsorbed on them.It was previously shown that apatite nuclei are formed on organic polymers when the polymers are placed on CaO, SiO2-based glass particles soaked in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma, and that they grow spontaneously to form a dense and uniform apatite layer together with high adhesive strength to the substrates when the polymers are soaked in another solution with ion concentrations 1.5 times the SBF. In the present study, silanol groups bonded covalently to the surface of the silicone substrate were formed and its apatite-forming ability was examined. When silicone substrates were treated with 5 or 10 M NaOH with pH 7.25 at 36.5°C for more than 3 h, silanol groups were formed on the surfaces of the substrates. When thus NaOH-treated substrates were soaked in 1.5SBF at 36.5°C, a bone-like apatite was formed on the substrates in a short period. © 1998 Chapman & Hall. 相似文献