巻号一覧
28 巻, 6 号
選択された号の論文の12件中1～12を表示しています
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有賀 規2000 年 28 巻 6 号 p. 331
発行日: 2000/06/15
公開日: 2010/03/17
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村上 浩一2000 年 28 巻 6 号 p. 332
発行日: 2000/06/15
公開日: 2010/03/17
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岡田 龍雄, 村本 准一, 中田 芳樹, 前田 三男2000 年 28 巻 6 号 p. 333-337
発行日: 2000/06/15
公開日: 2010/03/17
ジャーナル フリーThe particle dynamics during the synthesis process of nanopaticles by laser ablation in the background gas is described, based on the recent results of laser spectroscopic imaging studies. The nanoparticle synthesis processes in the silicon and YBa2Cu3Ox ablation plume have been visualized using laser-induced fluorescence (LIF), Rayleigh scattering and a newly developed decomposition-assisted LIF. Influences of the synthesis conditions on the particle dynamics are presented.抄録全体を表示PDF形式でダウンロード (1277K) -
2000 年 28 巻 6 号 p. 337-337,341
発行日: 2000/06/15
公開日: 2010/03/17
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牧村 哲也, 水田 泰治, 村上 浩一2000 年 28 巻 6 号 p. 338-341
発行日: 2000/06/15
公開日: 2010/03/17
ジャーナル フリーWe have investigated the formation of silicon nanoparticles after pulsed-laser ablation of a silicon target into argon gas at pressures of 2-10 Torr. Growing process of silicon nanoparticles was observed by measuring light emission resulting from decomposition of the nanoparticles by using a second pulsed-laser. It was directly observed that the nanoparticles are formed on the time scale of 1 ms, depending on the ambient gas pressure. This information is expected to be quite helpful for growth control and for chemical surface-modification by using pulsed-laser light or by exposure to a pulsed reactive-gas jet. The nanoparticles exhibit visible photoluminescence after deposition. Effect of chemical modification to photoluminescence have been investigated. Brighter luminescence have been observed from silicon nanocrystallites precipitated in SiO2 films during annealing of SiOx films deposited using a laser ablation technique.抄録全体を表示PDF形式でダウンロード (996K) -
小海 文夫, 高橋 邦充, 湯田坂 雅子, 飯島 澄男2000 年 28 巻 6 号 p. 342-347
発行日: 2000/06/15
公開日: 2010/03/17
ジャーナル フリーSingle-wall carbon nanotubes (SWNTs) were synthesized by the irradiation of a 20-ms CO2 laser pulse onto a graphite-Co/Ni (1.2 atomic %) target in an Ar gas atmosphere (600 Torr) from room temperature to 1200°C. To study the growth of SWNTs, we used emission imaging spectroscopy and shadowgraphy Wavelengthselected emission images showed that C2 emission was strong in the region close to the target (within 2 cm), while for the same region the blackbody radiation from the large clusters and/or particles increased with increasing distance from the target. Shadowgraph images revealed the formation of a mushroom or a turbulent cloud spreading slowly into the Ar atmosphere. In addition, emission imaging spectroscopy at 1200°C showed that C2 and hot clusters and/or particles with higher emission intensities distributed in much wider areas. At 1000-1200°C, the blackbody emission was observed for more than 1 s after the laser pulse. We discuss the growth dynamics of carbon-metal particles and SWNTs.抄録全体を表示PDF形式でダウンロード (2204K) -
佐々木 毅, 越崎 直人2000 年 28 巻 6 号 p. 348-353
発行日: 2000/06/15
公開日: 2010/03/17
ジャーナル フリーNanoparticles of metal oxides such as iron and cobalt oxides were prepared by pulsed laser ablation in Ar ambient at room temperature. The off-axis configuration of target and substrate greatly improved size distribution of the deposited nanoparticles. The morphology, crystallinity and oxidation states of the deposited nanoparticles and the nanoparticle-aggregated films were strongly dependent on the ablation pressure. The continuous and amorphous films consisting of the lower oxides such as FeO and CoO were deposited at lower pressure than 10 Pa. The formations of oxide nanoparticles of highly oxidized and crystallized phase such as Fe2O3 and Co3O4 were observed under the medium pressure range at around 100 Pa. The aggregates of nanoparticles were observed under higher pressure than 267 Pa. The size of the iron and cobalt oxide nanoparticles ranged from 2-9 nm and 2-4 nm, respectively. The basic ideas of growth mechanism are discussed.抄録全体を表示PDF形式でダウンロード (1896K) -
呉 海萍, 岡野 晃子, 高柳 邦夫2000 年 28 巻 6 号 p. 354-358
発行日: 2000/06/15
公開日: 2010/03/17
ジャーナル フリーWe produced silicon nanoparticles with diameters from 1 to 20 nm by laser ablation of Si in He mbient gas and extracted them into a vacuum as a cluster beam. Using a technique of crossing an Ar molecular beam perpendicularly to the silicon cluster beam before deposition on a substrate, we synthesized size-dispersed Si nanoparticle films. These size-dispersed nanoparticle films exhibited visible photoluminescence (PL) after exposure to air. The peak PL energy was shifted from 1.42 to 1.72 eV when the average diameter of the surface-oxidized nanoparticles deposited in the film changed from 10 to 3 or 4 nm. At positions that we expected to have particles smaller than 3 or 4 nm, however, we observed no further blue shift of the peak PL energy. In this paper, we discuss mechanisms of the size-dependent PL of the surface-oxidized Si nanoparticles.抄録全体を表示PDF形式でダウンロード (1189K) -
鈴木 薫, 宇留野 武見, 中田 順治2000 年 28 巻 6 号 p. 359-364
発行日: 2000/06/15
公開日: 2010/03/17
ジャーナル フリーWe report a successful selective technique for preparing single-phase boron-rich silicon borides (SiBx) films employing a pulsed Nd: YAG laser ablation method for multi-layer deposition, the results of which are designed for use in thermo-electric energy conversion device. In this process, SiBx films on silicon substrates were produced by the pulse laser ablation method using a multi-target (single bulk material target: Si and B) in 0.1 Torr argon gas. Nano-meter order silicon particles and boron particles were ablated by different shots numbers of Nd: YAG laser pulses, which deposited several hundred alternating layers of the particles. After the films were heated to about 1670 K for 10 hours under argon gas, x-ray diffraction patterns and electron probe micro analyzer (EPMA) analysis of these films showed a single-phase composition. As a result of the laser ablation process under several processing conditions, thin films of SiB4 or SiB6 are selectively presented about three microns thick and about six centimeters square. The influence of process parameters on morphology, phase diagram, electrical conductivity, thermal conductivity and Seebeck coefficient of the films were also discussed.抄録全体を表示PDF形式でダウンロード (1332K) -
川上 裕二, 瀬戸 章文, 山内 良浩, 小澤 英一2000 年 28 巻 6 号 p. 365-369
発行日: 2000/06/15
公開日: 2010/03/17
ジャーナル フリーRefractory metal ultrafine particles were synthesized by the irradiation of two synchronized-pulse Nd: YAG lasers on a refractory metal substrate in a low pressure inert gas atmosphere. A size distribution of the refractory metal ultrafine particles was measured by a low pressure differential mobility analyzer (LP-DMA) developed by ourselves for each pressure condition. The experimental results showed the peak of the size distribution was shifted from the several nm to the tens of nm level with increasing the pressure. The ultrafine particles of a 10 nm-size (σg=1.12) were precisely classified by the LP-DMA. We could control the shape of the particles from agglomeration condition to spherical one by using an electric furnace. In conclusion, the size classification of narrow distribution and the shape of the generated ultrafine particles could be well controlled.抄録全体を表示PDF形式でダウンロード (960K) -
今崎 一夫, 中尾 直也, 後藤 道夫, 文 雅司, 大東 延久, 綱脇 恵章, 三間 囲興, 中井 貞雄, 山中 千代衛2000 年 28 巻 6 号 p. 370-373
発行日: 2000/06/15
公開日: 2010/03/17
ジャーナル フリーOn the development of short wavelength Free Electron Lasers, there is a issue of the extremelylarge system. It is caused by high energy accelerator and a long wiggler. In order to solve this, we proposea system utilizing a microwiggler and seeding X-rays. Microwiggler makes it possible to lase at the wavelength of vacuum ultraviolet to soft X-ray with low energy electron beam. With seeding X-ray, quick start-up and thus short wiggler length are expected. We examined the validity of seeding X-ray using computer simulation. As a result, when seeding X-ray of 10 kW average power is supplied, it was shown that wiggler length for the radiation saturation was shortened by 60 %. We are going to use Laser-produced Plasma X-ray (LPX) for the seeding X-ray source. The technique of using an ellipsoid mirror to improve coupling efficiency of LPX to seeding X-ray is also discussed.抄録全体を表示PDF形式でダウンロード (565K) -
朝日 剛2000 年 28 巻 6 号 p. 374-377
発行日: 2000/06/15
公開日: 2010/03/17
ジャーナル フリーPDF形式でダウンロード (711K)
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