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排序方式: 共有2751条查询结果,搜索用时 15 毫秒
1.
Tsuneaki Matsudaira Masashi Wada Naoki Kawashima Miyuki Takeuchi Daisaku Yokoe Takeharu Kato Masasuke Takata Satoshi Kitaoka 《Journal of the European Ceramic Society》2021,41(5):3150-3160
Mass transfer in polycrystalline Yb2SiO5 wafers with precise composition control was evaluated and analyzed by oxygen permeation experiments at high temperatures using an oxygen tracer. Oxygen permeation proceeded due to mutual grain boundary diffusion of oxide ions and Yb ions without synergistic effects such as acceleration or suppression. The oxygen shielding properties of Yb2SiO5 were compared with those of the other line compounds such as Yb2Si2O7 and Al2O3 based on the determined mass transfer parameters. It was found that the more preferentially an oxide ion diffuses in the grain boundary compared to the interior of the grain, the greater the effect of suppressing the movement of the oxide ion by applying an oxygen potential gradient becomes. 相似文献
2.
Naoki Yokokawa Yutaro Masuda Eri Amasawa Hirokazu Sugiyama Masahiko Hirao 《Packaging Technology and Science》2020,33(11):445-459
This study presents systematic packaging design tools integrating functional and environmental consequences on product life cycle. To design packaging for sustainability, the trade-offs between functional and environmental aspects of packaging throughout the product life cycle should be considered. However, it is difficult for packaging designers to understand the overall trade-offs because the extent of the design consequences on the entire life cycle of packaging and its contents is unclear. We developed two tools for packaging design: the Life Cycle Association Matrix (LCAM) and the Function Network Diagram (FND). The following three steps, based on literature reviews and interviews with industrial experts, were applied. Firstly, we listed the product functions and design variables related to the functions as the attributes allocated to the product life cycle. Secondly, the attributes were connected appropriately based on causal relationships. Lastly, we identified the factors to support decision making in the packaging design procedure. As a result, the LCAM depicts the design consequences on the life cycle, and the FND determines the stakeholders affected by the design consequences. Two case studies were demonstrated to analyze the trade-offs by using our tools. In the case studies, a liquid laundry detergent bottle and a milk carton were redesigned. The tools identified the design consequences and stakeholders affected by the redesign of the usability and protective function for the detergent and milk cases, respectively. The results showed the significance of understanding the design consequences on the product life cycle by integrating the functional and environmental aspects. 相似文献
3.
Tuning-current splitting network for three-section DBR lasers 总被引:1,自引:0,他引:1
A simple current-splitting network for DBR-laser frequency tuning is proposed that distributes a single control current among two tuning sections and can adjust the current distribution without yielding impedance mismatching. The nonlinear characteristics of the tuning sections realise the non-proportional current splitting suitable for continuous tuning; 470 GHz (3.8 nm) tuning range is achieved 相似文献
4.
5.
Naoki Ichikawa Peter M. -Y. Chung Sohei Matsumoto Jun-ichi Matsumoto Naoki Takada 《Microgravity science and technology》2007,19(3-4):35-37
Ultrasound was applied to a micropipette micromixer to improve dispersion of gas and liquid in a microchannel. Flow visualization using a high-speed camera was performed to examine the effect of ultrasonic irradiation on bubble generation in the microchannel. Basically, nitrogen gas was injected using a (0.5 µm ID) glass micropipette into ethanol flowing in a rectangular (100 µm×200 µm) microchannel on polydimethylsiloxane (PDMS). Gas and liquid flow rates were regulated using mass flow controllers. At aflow condition that is typical of bubbly flow, ultrasound was transmitted into the microchannel using a piezo-electric (PZT) transducer over a range of operating voltages (2 to 200 Vp-p) and frequencies (50 to 60 kHz). Images captured during the action of the PZT transducer indicate that bubble formation is influenced by ultrasound. When subjected to ultrasound above 50 Vp-p and at the resonant frequency of the PZT transducer, bubbles formed that were smaller and closer together, signifying enhanced shearing of the gas at the micropipette tip by the liquid. The observation of gas slugs occurring sooner might be attributed to the coalescence of gas bubbles that became closely spaced. 相似文献
6.
Chihiro J. Uchibori Y. Ohtani T. Oku Naoki Ono Masanori Murakami 《Journal of Electronic Materials》1997,26(4):410-414
Significant reduction of the contact resistance of In0.7Ga0.3As/Ni/W contacts (which were previously developed by sputtering in our laboratory) was achieved by depositing a W2N barrier layer between the Ni layer and W layer. The In0.7Ga0.3 As/Ni/W2N/W contact prepared by the radio-frequency sputtering technique showed the lowest contact resistance of 0.2 Ωmm after annealing
at 550°C for 10 s. This contact also provided a smooth surface, good reproducibility, and excellent thermal stability at 400°C.
The polycrystalline W2N layer was found to suppress the In diffusion to the contact surface, leading to improvement of the surface morphology and
an increase in the total area of the InxGa−As between metal and the GaAs substrate. These improvements are believed to reduce the contact resistance. 相似文献
7.
D. Xu T. Enoki T. Suemitsu Y. Umeda H. Yokoyama Y. Ishii 《Journal of Electronic Materials》1998,27(7):L51-L53
We have achieved a self-controlled asymmetrical etching in metalorganic chemical vapor deposition-grown InAlAs/InGaAs heterostructures,
which can be suitable for fabricating modulation-doped field-effect transistors (MODFETs) with gate-groove profiles for improved
performance. The technology is based on electrochemical etching phenomena, which can be effectively controlled by using different
surface metals for ohmic electrodes. When surface metals of Pt and Ni are deposited on the source and the drain, respectively,
the higher electrode potential of Pt results in slower etching on the source side than on the drain side. Thus, asymmetry
of gate grooves can be formed by wet-chemical etching with citric-acid-based etchant. This represents a new possibility to
conduct “recess engineering” for InAlAs/InGaAs MODFETs. 相似文献
8.
For the first time, the surface metal on nonalloyed ohmic electrodes is found to significantly change the profiles of gate grooves, when resist openings are employed to monitor drain current during wet-chemical gate recess for sub-micron InAlAs/lnGaAs heterojunction field-effect transistors (HFETs). The surface metal of Ni enhances the etching rate in comparison with that in the absence of electrodes by a factor of 4 and 10, laterally and vertically, which is favorable to fabricate deep gate grooves with small side etching. The Pt surface metal, however, leads to preferential etching of InGaAs over InAlAs, which can be useful to realize large side etching. The existence of an electrochemistry-related etching component, which arises when the ohmic electrodes are present during recess etching, is considered to be responsible for these behaviors 相似文献
9.
A design for composite-channel structures consisting of an InGaAs channel and an InP subchannel for use as heterostructure field-effect transistors is presented for the first time. This novel channel structure takes advantage of both the high drift velocity and low impact ionization of InP at high electric fields as well as the high electron mobility of InGaAs at low electric fields. It is shown that the doping density of the InP subchannel is the key parameter to realize the advantages of the composite channel. A very high transconductance of 1.29 S/mm and a current gain cutoff frequency of 68.7 GHz are achieved with 0.6 and 0.7 /spl mu/m gates, respectively. The average velocity of electrons in the composite channel is 2.9/spl times/10/sup 7/ cm/s. The devices have no kink phenomena in their I-V characteristics possibly due to low impact ionization in the InP subchannel.<> 相似文献
10.
The inhibitory effect of alpha-tocopherol on methemoglobin formation in normal and acatalasemic mice was studied by exposing their hemolysates to nitric oxide. Methemoglobin formation in normal and acatalasemic mouse hemolysates exposed to nitric oxide were significantly inhibited by the addition of alpha-tocopherol at final concentrations ranging from 1.2 to 5.8 mM. Negative correlations were observed between the logarithm of alpha-tocopherol concentration and the methemoglobin formation. The formation of methemoglobin in acatalasemic mouse hemolysates was greater than that in normal mouse hemolysates with or without added alpha-tocopherol. The methemoglobin formation in acatalasemic mice was also significantly inhibited by addition of more than 500 units/ml of catalase, and the methemoglobin formation in normal and acatalasemic mice was also inhibited with sodium diethyldithiocarbamate at a final concentration of 1 M. 相似文献