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981.
H. Tanaka K. Akinaga A. Takahashi T. Okada 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1493-1495
Nano-structured and tin-based targets have been fabricated by the pulsed-laser ablation method, in order to develop efficient and debris-free targets for the laser-produced plasma extreme ultraviolet (EUV) light source at 13.5 nm. Characteristic spectra that have the radiation peak around 13.5 nm were obtained from CO2 laser produced plasma using the films as a target. A nano-structured target produced EUV light as intense as a bulk target and a narrower line spectrum at 13.5 nm than a bulk target. PACS 32.30.Rj; 52.38.-r; 52.38.Mf; 61.46.+w; 68.37.-d 相似文献
982.
983.
Effect of radiation damage on luminescence of erbium-implanted SiO2/Si studied by slow positron beam
A. Kawasuso H. Arai K. Hirata T. Sekiguchi Y. Kobayashi S. Okada 《Radiation Physics and Chemistry》2000,58(5-6):615-619
The effect of damage on 1.54 μm luminescence for 30 keV-Er-implanted SiO2 films has been studied by positron annihilation and cathodoluminescence. It was found that S-parameter in the films decreased after implantation, indicating the suppression of positronium formation. The luminescence appeared with the recovery of the S-parameter after 600°C annealing. The intensity reached a maximum at 900°C annealing whereas the S-parameter did not change significantly. It seems that most damages recover at 600°C and thereafter Er ions transform to an optically active state at 900°C. 相似文献
984.
The paper describes results obtained from plate-impact pressure-shear friction experiments to investigate the phenomena of high-speed slip at metal-on-metal interfaces. Using a CH tool-steel/Ti-6Al-4V tribo-pair the authors have studied the effects of normal pressure, slip-speed, temperature and surface roughness on the evolution of the dynamic slip-resistance. Moreover, a finite-element procedure is developed to simulate the evolution of thermo-mechanical fields and understand their relationship to the observed slip response.Next, the pressure-shear friction experiments are extended to investigate the behavior of CH tool-steel/7075-T6 Al alloy tribo-pair. This material combination allows dynamic friction characteristics to be studied in the near-melt and the fully melt temperature regime of the lower-melting-point metal (7075-T6 Al alloy) comprising the tribo-pair. Besides providing information on the slip-velocity versus friction-stress relationship under extreme interfacial conditions, the experiments provides critical information on the shearing resistance of confined molten metal films under high pressures and extremely high shearing rates. 相似文献
985.
986.
Masayuki Ishikawa Yoshimi Okada 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2004,80(5):215
Tobamovirus is a positive-strand RNA virus of plants. Its single-stranded RNA genome replicates via the negative-strand RNA. In this review, we describe our current knowledge about viral and host factors associated with tobamovirus RNA replication and discuss the replication mechanisms. We also mention the usefulness of tobamovirus genomes as vectors. 相似文献
987.
Two-dimensional rotational temperature measurement was performed in a stable combustion flame of premixed butane and oxygen using multiline laser induced fluorescence (LIF) of nitric oxide molecules. Multiple rotational absorption lines of A2∑+Π;X2II(0,0) Q1 and Q2 lines were excited by laser light around 226 nm, and the LIF signal was observed by an image-intensified digital camera. Temperature was determined through least squares fitting correlation between LIF intensity and excitation rotational quantum number for the Boltzmann distribution function. The measured LIF intensity was approximated by the Boltzmann distribution with good accuracy, and the temperature obtained was between 500 K and 1800 K for the test flame. The measuring error of the temperature was evaluated and found to be 80 K, which corresponded to 8% of the measured fluorescence intensity. The two-line LIF scheme was evaluated by different pairs of excitation lines (Q1(31.5)/Q1(16.5) and Q1(18.5)/Q1(16.5)) for comparison with the multiline LIF approach. Temperature which was obtained by two-line LIF scheme corresponded well with multiline LIF results for Q1(31.5)/Q1(16.5) excitation. However, for Q1(18.5)/Q1(16.5) excitation, the obtained temperature did not agree with the multiline LIF result because the population of rotational states J=18.5 and J=16.5 is similar at high temperatures. We found that two-line LIF temperature measurement was reliable when excitation lines were suitably selected. 相似文献
988.
Near infrared topographic imaging is a novel non-invasive technique to obtain the activated region in the brain cortex. The light propagation in the head is strongly scattered and this causes results in poor spatial resolution and contrast in the topographic images. Adequate modelling of light propagation in the head in order to deduce the volume of tissue interrogated by a source-detector pair for topographic imaging is very important to improve the quality of image of brain activity. In this study, the light propagation in a three-dimensional realistic head model is calculated by the finite difference method. The geometry of the model is generated from axial slices of an MRI scan. The topographic image is obtained from the change in intensity detected by source-detector pairs caused by the brain activity. The images obtained by two types of source-detector arrangement are compared to evaluate the efficiency of source-detector arrangement. The results show that the double-density arrangement improves the quality of the topographic image of the brain activity. 相似文献
989.
Tokimec has been developing high grade interferometric fiber-optic gyroscopes (I-FOGs) for useful applications. The I-FOG
consists of a sensing coil module, a light emitting module and an electronics circuits module. We achieved the bias stability
of 0.003 deg/h and the angular random walk of 0.001 deg/√h and the scale factor error of 10 ppm (1σ). Then the azimuth error
of the strapdown gyrocompass system with the high grade I-FOGs was less than ±0.05 s λ (deg) under the environmental temperature
condition 23±5(°C). 相似文献
990.
N. Kitazawa T. Kobayashi N. Maru N. Okada 《The European Physical Journal C - Particles and Fields》2005,40(4):579-587
The structure of Yukawa coupling matrices is investigated in type IIA T
6/(Z2 x Z2) orientifold models with intersecting D-branes. Yukawa coupling matrices are difficult to be made realistic in conventional models in which the generation structure emerges by the multiple intersection of D-branes in the factorized T
6 = T
2 x T
2 x T
2. We study the new type of flavor structure, where Yukawa couplings are dynamically generated, and show this type of models lead to non-trivial structures of Yukawa coupling matrices, which can be realistic.Received: 8 December 2004, Revised: 22 December 2004, Published online: 9 March 2005 相似文献