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991.
Ultra-low-energy ion implantation of silicon with a hydrogen-terminated (0 0 1) surface was carried out using a mass-separated 31P+ ion beam. The ion energy was 30 eV, the displacement energy of silicon, and the ion doses were 6 × 1013 ions/cm2. Annealing after the implantation was not carried out. The effects of ion implantation on the surface electrical state of silicon were investigated using X-ray photoelectron spectroscopy (XPS). The Si 2p peak position using XPS depends on the doping conditions because the Fermi level of the hydrogen-terminated silicon surface is unpinned. The Si 2p peak position of the specimen after ion implantation at a vacuum pressure of 3 × 10−7 Pa was shifted to the higher energy region. It suggested the possibility of phosphorus doping in silicon without annealing. In the case of ion implantation at 5 × 10−5 Pa, the Si 2p peak position was not shifted, and the peak was broadened because of the damage by the fast neutrals. Ultra-low-energy ion doping can be achieved at ultra-high-vacuum conditions. 相似文献
992.
T. Sakuma Xianglian S. Siagian K. Basar H. Takahashi N. Igawa O. Kamishima 《Journal of Thermal Analysis and Calorimetry》2010,99(1):173-176
Neutron diffraction measurements have been performed on powder VSe at 294 K. The diffuse scattering theory including correlation
effects among thermal displacements of atoms is applied to background function in the Rietveld analysis. The oscillatory scheme
of the diffuse scattering intensity from hexagonal VSe is explained by the correlation effects among far-neighboring Se–Se
atoms. The values of the correlation effects depend on the inter-atomic distance and not on the crystal structure. The relation
between correlation effects and force constants is discussed. 相似文献
993.
994.
Kazuhiro Yamamoto Takafumi Kamimura Kazuhiko Matsumoto 《Applied Surface Science》2006,252(15):5579-5582
Mass-separated ultra-low-energy oxygen ion beams were irradiated to the single-walled carbon nanotubes (SWCNTs) under an ultra-high-vacuum pressure of 10−7 Pa for the purpose of achieving n-type conduction of nanotubes. The ion beam energy was 25 eV, which was close to the displacement energy of graphite. The incident angle of the ion beam was normal to the target nanotube. The ion dose ranged from 3.3 × 1011 to 3.8 × 1012 ions/cm2. The structure of SWCNTs after the ion irradiation was investigated. The CNTs still have a clear single-walled structure after the ion irradiation. The graphite structure is distorted and some defects are induced in the nanotube by the oxygen irradiation. The oxygen ions with the ion energy of 25 eV are irradiated to the field effect transistor (FET) device with the nanotube channel. The n-type characteristic appears upon the oxygen ion irradiation, and the device exhibits ambipolar behavior. The defects induced by the ion irradiation may act as the n-type dopants. 相似文献
995.
The present paper considers the existence of continuous roots of algebraic equations with coefficients being continuous functions defined on compact Hausdorff spaces. For a compact Hausdorff space X, C(X) denotes the Banach algebra of all continuous complex-valued functions on X with the sup norm ∥⋅∥∞. The algebra C(X) is said to be algebraically closed if each monic algebraic equation with C(X) coefficients has a root in C(X). First we study a topological characterization of a first-countable compact (connected) Hausdorff space X such that C(X) is algebraically closed. The result has been obtained by Countryman Jr, Hatori-Miura and Miura-Niijima and we provide a simple proof for metrizable spaces.Also we consider continuous approximate roots of the equation zn−f=0 with respect to z, where f∈C(X), and provide a topological characterization of compact Hausdorff space X with dimX?1 such that the above equation has an approximate root in C(X) for each f∈C(X), in terms of the first ?ech cohomology of X. 相似文献
996.
Kazuaki Kouyama Masaya Inoue Yuta Inose Naoki Suzuki Hiroto Sekiguchi Hideyuki Kunugita Kazuhiro Ema Akihiko Kikuchi Katsumi Kishino 《Journal of luminescence》2008,128(5-6):969-971
We measured photoluminescence (PL) from excitons and biexcitons in GaN nanocolumns at low temperature and found that the PL spectra of excitons depend on the nanocolumn diameter. Taking into account the polaritonic effect of the excitons, calculation of the PL spectra revealed that the dependence on diameters causes a difference of PL intensity from side surfaces of the nanocolumns. At high excitation intensities, we also observed biexciton emissions and found that the biexciton binding energies are higher than those in bulk samples. Although the mechanism for the increase in the binding energy is not clear at present, we suppose that it arises from a spatial confinement effect due to the nanocolumn morphology. 相似文献
997.
Kei-Ichi Akabori Daisuke Baba Kazuhiro Koguchi Keiji Tanaka Toshihiko Nagamura 《Journal of polymer science. Part A, Polymer chemistry》2006,44(24):3598-3604
Polystyrene (PS) bilayers were prepared and were adhered at a temperature between the surface and bulk glass-transition temperatures for a given time. Then, the interfacial adhesion strength (GL) was examined with a conventional lap-shear measurement. GL first increased with increasing adhesion time and then reached a constant value. This result implied that the segments moved across the interface, to a certain depth, even at a temperature below the bulk glass-transition temperature. To confirm this, the interfacial evolution for the PS/deuterated PS bilayers was examined with dynamic secondary-ion mass spectrometry. The GL value was linearly proportional to the thickness of the interfacial adhesion layer. Finally, we propose a strategy for regulating the adhesion strength based on the chain-end chemistry. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3598–3604, 2006 相似文献
998.
999.
We report experiments on deflecting cold 87Rb atoms by repulsive near-field light induced in a 200-nm-wide slit. The spatial profile is measured with a two-step photoionization
scan. The number of outputted atoms from the slit increases by the amount of 40 ± 7.2% at a 5.1 ± 2.0° angle for the blue
detuning of +1 GHz. We discuss the spatial profile involving an image of the atomic cloud by means of the scattering cross
section. 相似文献
1000.
Daisuke Noda Masao Tanabiki Kazuhiro Tsuchiya Yusuke Sunada Hideo Nagashima 《Polyhedron》2009,28(18):3935-3944
A series of azanickellacyclopentene complexes having iodo, bromo, chloro, or triflate ligand on the Ni center were prepared, and are subjected to studies on ethylene polymerization catalysis. Activity of these mononuclear azanickellacyclopentene complexes was increased in the order, Ni–Cl < Ni–I ≈ Ni–Br < Ni–OTf; this is explained by the performance of (pseudo)halogeno ligand as a leaving group from the nickel center. Methylalminoxane (MAO) and inexpensive AlEt2Cl can be used as the cocatalyst. Mechanistic consideration suggested the involvement of neutral Ni-alkyl intermediates as proposed in the SHOP type catalytic system. Interestingly, the catalytic activity is significantly increased by incorporating the second metals into the diimino moiety of mononuclear complex. Two factors should be considered to explain this activity enhancement. One is the increased rigidity of the azanickellacyclopentene ligand backbone, and the other is the possibility of the presence of the two active centers in one molecule. 相似文献