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排序方式: 共有323条查询结果,搜索用时 15 毫秒
21.
Manabu Shimada Heru Setyawan Yutaka Hayashi Nobuki Kashihara Kikuo Okuyama Sugeng Winardi 《Aerosol science and technology》2013,47(5):408-414
The effects of gas flow rate on particle formation and film deposition during the preparation of silica thin film using a TEOS/O2 plasma were investigated. Particle formation and growth are suppressed with increasing gas flow rates. The film deposition rate increases with increasing gas flow rate, reaches a maximum value, and eventually decreases again. However, the uniformity of the film tends to degrade at high gas flow rates. At a high gas flow rate, some particles trapped in the sheath near the grounded electrode pass through the sheath to reach the substrate and are then embedded in the growing film. A self-consistent sheath model combined with particle force balance based on charge fluctuation was developed to explain these experimental findings qualitatively. The model reveals that charge fluctuation is a key factor for the particle to overcome the potential barrier of the negatively charged particles to pass through the sheath, eventually reaching the substrate. The model further shows that the probability of a particle being deposited on the substrate is higher for increased gas flow rates, which correctly predicts the experimentally observed trend. 相似文献
22.
Xin-yun Wang Nobuki Yukawa Yoshinori Yoshita Takuya Sukeda Takashi Ishikawa 《Journal of Materials Processing Technology》2009,209(6):3030-3038
Due to the disadvantages in casting or hot forging of Ti alloy artificial bones, such as low strength and high energy cost, this paper prompted an alternative method to manufacture individuated artificial bones. Free forging with a 6-axis freedom robot and servo-press could be very economical in the forming of complex shape parts because of its high flexibility and simple die-setting. Based on this system, the authors studied deformations of some basic elements, which could be assembled to artificial bones with complex shape. Firstly, the compression limit and effect of compression parameters on the roundness during reducing diameter process were declared for Al alloy and pure Ti. Secondly, an approximate theoretical equation of bending angle or curvature radius was proposed, and it matches experimental results well. Finally, a dimension prediction equation was presented by considering effect of material anisotropy, and then the ladder part without width spread was manufactured accordingly. 相似文献
23.
We investigated the diffusion process of H2O2 generated during O2 reduction at a Pt microdisk electrode used as a generator for scanning electrochemical microscopy (SECM). First, the amount of O2 consumption and generated H2O2 at the Pt generator electrode are estimated using a detector electrode installed in the SECM. Based on the results, a large amount of O2 consumption and generated H2O2 are detected at the center of each generator electrode. According to the measurement, the O2 starvation and H2O2 detection currents can be defined. Subsequently, the O2 starvation and H2O2 detection currents are measured by varying the generator size. As a result, these currents decrease with a decrease in the generator electrode size, however, the H2O2 diffusion process is changed for the generator diameter of less than 50 μm. Finally, the O2 starvation and H2O2 detection measurements were conducted using a Nafion-coated Pt microdisk electrode. The amount of O2 consumption is not suppressed, while the amount of generated H2O2 decreases with the Nafion layer prepared on the Pt electrode. This result indicates that the thickness of the H2O2 diffusion layer in the H2SO4 solution is dramatically diminished by coating the Nafion layer on the Pt generator. 相似文献
24.
The productivity associated with commonly available disassembly methods today seldomly makes disassembly the preferred end-of-life solution for massive take back product streams. Systematic reuse of parts or components, or recycling of pure material fractions are often not achievable in an economically sustainable way. In this paper a case-based review of current disassembly practices is used to analyse the factors influencing disassembly feasibility. Data mining techniques were used to identify major factors influencing the profitability of disassembly operations. Case characteristics such as involvement of the product manufacturer in the end-of-life treatment and continuous ownership are some of the important dimensions. Economic models demonstrate that the efficiency of disassembly operations should be increased an order of magnitude to assure the competitiveness of ecologically preferred, disassembly oriented end-of-life scenarios for large waste of electric and electronic equipment (WEEE) streams. Technological means available to increase the productivity of the disassembly operations are summarized. Automated disassembly techniques can contribute to the robustness of the process, but do not allow to overcome the efficiency gap if not combined with appropriate product design measures. Innovative, reversible joints, collectively activated by external trigger signals, form a promising approach to low cost, mass disassembly in this context. A short overview of the state-of-the-art in the development of such self-disassembling joints is included. 相似文献
25.
B. Chen S. K. Moon X. Yao G. Bi J. Shen J. Umeda K. Kondoh 《JOM Journal of the Minerals, Metals and Materials Society》2018,70(5):644-649
The microstructural and mechanical properties of AlSi10Mg alloys fabricated by additive manufacturing (AM) and powder metallurgy (PM) routes were investigated and compared. The microstructures were examined by scanning electron microscopy assisted with electron-dispersive spectroscopy. The crystalline features were studied by x-ray diffraction and electron backscatter diffraction. Room-temperature tensile tests and Vickers hardness measurements were performed to characterize the mechanical properties. It was found that the AM alloy had coarser Al grains but much finer Si precipitates compared with the PM alloy. Consequently, the AM alloy showed more than 100% increment in strength and hardness compared with the PM alloy due to the presence of ultrafine forms of Si, while exhibiting moderate ductility. 相似文献
26.
Dr. Naoki Umezawa Yuhei Horai Dr. Yuki Imamura Makoto Kawakubo Mariko Nakahira Dr. Nobuki Kato Akira Muramatsu Prof. Dr. Yuko Yoshikawa Prof. Dr. Kenichi Yoshikawa Prof. Dr. Tsunehiko Higuchi 《Chembiochem : a European journal of chemical biology》2015,16(12):1811-1819
A versatile solid‐phase approach based on peptide chemistry was used to construct four classes of structurally diverse polyamines with modified backbones: linear, partially constrained, branched, and cyclic. Their effects on DNA duplex stability and structure were examined. The polyamines showed distinct activities, thus highlighting the importance of polyamine backbone structure. Interestingly, the rank order of polyamine ability for DNA compaction was different to that for their effects on circular dichroism and melting temperature, thus indicating that these polyamines have distinct effects on secondary and higher‐order structures of DNA. 相似文献
27.
Isolation and characterization of poly(butylene succinate-co-butylene adipate)-degrading microorganism 总被引:1,自引:0,他引:1
Hayase N Yano H Kudoh E Tsutsumi C Ushio K Miyahara Y Tanaka S Nakagawa K 《Journal of Bioscience and Bioengineering》2004,97(2):131-133
Poly(butylene succinate-co-butylene adipate) (PBSA)-degrading bacterium, strain 1-A, was isolated from soil. Strain 1-A was identified as Bacillus pumilus on the basis of its physiological properties and partial 16S rRNA gene sequence. Strain 1-A also degraded poly(butylene succinate) (PBS) and poly(epsilon-caprolactone). On the other hand, poly(butylene adipate terephthalate) and poly(lactic acid) were minimally degraded by strain 1-A. The NMR spectra of degradation products from PBSA indicated that the adipate units were more rapidly degraded than 1,4-butanediol and succinate units. This seems to be one of the reasons why strain 1-A degraded PBSA faster than PBS. 相似文献
28.
Novel transdermal drug delivery system with polyhydroxyalkanoate and starburst polyamidoamine dendrimer 总被引:1,自引:0,他引:1
Wang Z Itoh Y Hosaka Y Kobayashi I Nakano Y Maeda I Umeda F Yamakawa J Kawase M Yag K 《Journal of Bioscience and Bioengineering》2003,95(5):541-543
In search of an efficient transdermal drug delivery system (TDDS), a polyhydroxyalkanoate (PHA)-based system with a polyamidoamine dendrimer was examined. Tamsulosin was used as the model drug. The dendrimer was found to act as the weak enhancer. By adding the dendrimer, the dendrimer-containing PHA matrix achieved the clinically required amount of tamsulosin permeating through the skin model. This is also the first report of the application of PHA and dendrimer to the TDDS. 相似文献
29.
Xu D. Suemitsu T. Osaka J. Umeda Y. Yamane Y. Ishii Y. Ishii T. Tamamura T. 《Electron Device Letters, IEEE》1999,20(5):206-208
We have developed high-performance enhancement-mode InP-based modulation-doped field-effect transistors with 0.03 μm gate-length. A record high current gain cutoff frequency exceeding 300 GHz has been achieved, and the maximum extrinsic transconductance is as high as 2 S/mm with an associated drain current of 0.5 A/mm at a drain bias of 1 V. This high performance is a result of the reduction or gate length, the use of the high barrier metal Pt as gate electrodes, and most importantly the employment of the well-developed wet-etching technology that allows the formation of a very deep gate groove while retaining small side etching. The excellent E-MODFET performance opens up the possibility of implementing ever faster high-speed circuits based on direct-coupled FET logic 相似文献
30.
An investigation is reported in which, to ensure that the noise control of a shuttle-weaving mill set the restricted noise level at the boundary between the sill and its neighbours, the noise-transmission loss of twelve kinds of mill wall was investigated by using the “reverberant room versus reverberant room” method. On the basis of the results obtained, several plans for the reconstruction of a shuttle-weaving mill are suggested, and the results obtained after such a reconstruction are discussed. 相似文献