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61.
We report on photocarrier transport of high-growth-rate microcrystalline Si (μc-Si) in conjunction with the lateral size, σL, of crystallites’ conglomerate (grain) determined from the atomic force microscope (AFM) topographic images on the basis of fractal concepts. μc-Si films were prepared using very-high-frequency plasma-enhanced chemical vapor deposition at a high deposition rate of 6.8 ± 0.5 nm/s. μc-Si thicknesses, d, were varied from 0.53 μm to 5.6 μm. With an increase in d, σL increased from 70 nm to 590 nm. At the same time, the ambipolar diffusion lengths, Lamb, of photocarriers, observed using the steady-state photocarrier grating (SSPG) technique, increased from 50 nm to 420 nm. Log–log plots of Lamb versus d and σL versus d were both expressed as a power law with an exponent of 0.9, yielding a simple linear relation between Lamb and σL. Moreover, their ratio, Lamb/σL, was below unity, implying the intra-grain carrier diffusion. From these results, the role of the grain (column) boundaries for photocarrier diffusion in μc-Si is discussed. 相似文献
62.
After the appearance of W. Arendt's result that “Gaussian estimate of a semigroup implies the Lp-spectral independence of the generator,” various generalizations have been obtained. This paper shows that a certain kernel estimate of a semigroup implies the Lp-spectral independence of the generator, generalizing the case of upper Gaussian estimate and “Gaussian estimate of order α(0,1] [S. Miyajima, H. Shindoh, Gaussian estimates of order α and Lp-spectral independence of generators of C0-semigroups, Positivity 11 (1) (2007) 15–39], Definition 3.1.” The proof uses S. Karrmann's result about the Lp-spectral independence and B.A. Barnes' theorem about the spectrum of integral operators. As an application, the Lp-spectral independence of −[(−Δ)α+V] (α(0,1]) for a suitable V is proved with the help of a recent result by V. Liskevich, H. Vogt and J. Voigt [V. Liskevich, H. Vogt, J. Voigt, Gaussian bounds for propagators perturbed by potentials, J. Funct. Anal. 238 (2006) 245–277]. 相似文献
63.
Intramolecular hydrogen atom tunneling in 2-chlorobenzoic acid has been investigated by low-temperature matrix-isolation infrared spectroscopy with the aid of density functional theory calculation. Infrared spectra of two relatively stable syn isomers, SC and ST, were observed in argon and xenon matrixes. When the matrix samples were annealed after deposition, the isomerization from ST to SC occurred around the benzene-carboxyl bond. Two less stable anti isomers, AT, which has an OH...Cl intramolecular hydrogen bond, and AC, which has no OH...Cl bond, were produced from SC and ST upon UV irradiation. When the matrix samples were kept in the dark after UV irradiation, AT and AC changed to ST and SC, respectively, by spontaneous isomerization around the C-O axis in the carboxyl group. The rate constants of isomerization, AT --> ST, in a Xe matrix were estimated from the absorbance changes at various matrix temperatures. The rate constants showed a drastic decrease in deuteration of the hydrogen atom of the carboxyl group. The relationship between the rate constants and the matrix temperature did not follow the Arrhenius law. These findings lead to the conclusion that the isomerization of AT --> ST and AC --> SC in low-temperature rare-gas matrixes proceeds through intramolecular hydrogen atom tunneling. 相似文献
64.
The disintegratability of tablets prepared from two types of solid dispersions containing the water-soluble polymer TC-5 and the enteric polymer HP-55 as an excipient were compared. The disintegratability was better in the tablets of solid dispersions containing non-water-soluble HP-55 than those containing TC-5. In consideration of the dissolubility of solid dispersions containing HP-55, the mean diameter of the solid dispersion (coating powder) must be controlled to 120 microm or less, but as this markedly increases the adhesion/aggregation tendency of the particles (angle of repose: 47 degrees ), control of the adhesion/aggregation tendency emerged as another problem. Therefore, surface-modification was performed in a high-speed agitating granulator using 0.1% light anhydrous silicic acid as a surface modifier, and marked improvement in the flowability was observed. This made continuous tableting using a rotary tablet machine possible even with the poorly flowable solid dispersions. Also, in tableting of the solid dispersions, no recrystallization of amorphous itraconazole by the tableting pressure was observed, and the tablets maintained satisfactory dissolubility. Moreover, it was possible to obtain the rapidly disintegrating tablets with very satisfactory properties, i.e., a tablet hardness of 30 N or higher and a disintegration time of 30 s or less, by the addition of croscarmellose as a disintegrant at 2% to the surface-modified solid dispersion and selection of the tableting pressure at 4.5 kN. 相似文献
65.
We prove Lp-spectral independence for generators of C0-semigroups estimated by the positive C0-semigroup . In the preliminary process of the proof, we obtain the asymptotic expansion formula for the integral kernel of the C0-semigroup . 相似文献
66.
Takayuki Toyoda Hisakazu Mihara Akihiko Ueno 《Macromolecular rapid communications》2002,23(15):905-908
Peptides bearing β‐cyclodextrin and 4‐(N,N‐dimethylamino)benzoyl (DMAB) units in the peptide side chains were prepared as chemosensors for molecule detection. The DMAB unit was expected to be included into the cyclodextrin cavity intramolecularly. However, these peptides exhibited no twisted intramolecular charge transfer fluorescence and the normal fluorescence intensity decreased upon the addition of 1‐adamantanol as an exogenous guest, indicating that the DMAB units are shallowly included in the cyclodextrin cavities. 相似文献
67.
The pulsed intense ion beam, emitted from a dense plasma focus (DPF) discharges performed with hydrogen gas, has been used to ablate the graphite target depositing diamond-like carbon (DLC) films on Si substrates. The substrates were mounted on a holder, which allowed for deposition at positions between normal and 20° off-normal to the target. The samples were removed for analysis after 10 and 20 shots. Nano-particles were observed in the films by a field-emission scanning electron microscope. Raman spectra indicate that sample deposited at 20° off-normal with 20 shots possesses the highest sp3 content among the samples. The film deposited at this position was also found has the highest hardness. 相似文献
68.
S. Matsuyama M. Shimura H. Mimura M. Fujii H. Yumoto Y. Sano M. Yabashi Y. Nishino K. Tamasaku T. Ishikawa K. Yamauchi 《X射线光谱测定》2009,38(2):89-94
To visualize the distributions of trace elements in biological samples such as tissues and cells at high spatial resolution, we developed a scanning x‐ray fluorescence microscope (SXFM) at SPring‐8, using a Kirkpatrick‐Baez mirror optics that enables achromatic and highly efficient focusing. To evaluate performance regarding its application to biological samples, the SXFM was used at x‐ray energy of 15 keV to observe NIH/3T3 cells in which adenosine triphosphate (ATP) synthase β (specifically localized at the mitochondria) were labeled with gold colloidal particles. Various elemental distributions were visualized at the single‐cell level, including those for P, S, Cl, Ca, Fe, Cu, Zn and Au, and we obtained high‐resolution elemental distribution maps by magnifying the labeled single mitochondrion. Maximum spatial resolution achieved in the experiments was sub‐100 nm. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
69.
Ryuta Nishida Katsuyoshi Kakinuma Hanako Nishino Takeo Kamino Hisao Yamashita Masahiro Watanabe Hiroyuki Uchida 《Solid State Ionics》2009,180(14-16):968-972
Aiming at SOFC anode applications, we have synthesized nanometer-sized nickel catalysts supported on hollow spherical particles of samaria-doped ceria (Ni/SDC) by spraying a mixed solution of nickel, samarium, and cerium nitrates into an atmospheric pressure plasma. The as-prepared particles consisted of SDC (average diameter dSDC = ca. 0.8 µm) and uniformly dispersed nanometer-sized NiO particles. When reduced in H2 at 800 °C or 1000 °C, Ni nanoparticles (average diameter dNi = 34 nm) were found to be embedded uniformly into the SDC surface. 相似文献
70.
Surface structures on rutile TiO2 (001) have been studied by using scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and density functional calculations. Prior investigations have observed many kinds of complicated surface structures; however, detailed atomic structures and the mechanism of the reconstructions are still unknown. We evaluate the energetical stability of the surface structures. The calculational results suggest that a [111] microfaceting model is energetically stable compared with the unreconstructed (1 x 1) model. We propose microfaceting structural models that are in good agreement with atomically resolved STM images. This structural concept can be extended to other rutile TiO2 surfaces in general. 相似文献