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111.
Takai Y. Fujita M. Nagata K. Isa S. Nakazawa S. Hirobe A. Ohkubo H. Sakao M. Horiba S. Fukase T. Takaishi Y. Matsuo M. Komuro M. Uchida T. Sakoh T. Saino K. Uchiyama S. Takada Y. Sekine J. Nakanishi N. Oikawa T. Igeta M. Tanabe H. Miyamoto H. Hashimoto T. Yamaguchi H. Koyama K. Kobayashi Y. Okuda T. 《Solid-State Circuits, IEEE Journal of》2000,35(2):149-162
This paper describes three circuit technologies indispensable for high-bandwidth multibank DRAM's. (1) A clock generator based on a bidirectional delay (BDD) eliminates the output skew. The BDD measures the cycle time as the quantity charged or discharged of an analog quantity, and replicates it in the next cycle. This achieves a 0.18-mm 2, two-cycle-lock clock generator operating from 25 to 167 MHz with a 30-ps resolution. (2) A quad-coupled receiver eliminates the internal skew caused by the difference between a rise input and a fall input by 40%. (3) An interbank shared redundancy scheme (ISR) with a variable unit redundancy (VUR) efficiently increases yield in multibank DRAM's. The ISR allows redundancy match circuits to be shared with two or more banks. The VUR allows the number of units replaced to be variable. These circuit technologies achieved a 250-Mb/s/pin, 8-bank, 1-Gb double-data-rate synchronous DRAM 相似文献
112.
Tomoyuki Kawase Kazuhiro Okuda Hiroyuki Kogami Hitoshi Nakayama Masaki Nagata Hiromasa Yoshie 《Journal of materials science. Materials in medicine》2010,21(2):731-739
Our animal implantation studies have demonstrated that, after osteogenic processing, cultured human periosteal sheets form
osteoid tissue ectopically without the aid of conventional scaffolding materials. To improve the osteogenic activity of these
periosteal sheets, we have tested the effects of including a scaffold made of salmon collagen-coated ePTFE mesh. Periosteal
sheets were produced with minimal manipulation without enzymatic digestion. Outgrown cells penetrated into the coated mesh
fiber networks to form complex multicellular layers and increased expression of alkaline phosphatase activity in response
to the osteoinduction. In vitro mineralization was notably enhanced in the original tissue segment regions, but numerous micro-mineral
deposits were also formed on the coated-fiber networks. When implanted subcutaneously into nude mice, periosteal sheets efficiently
form osteoid around the mineral deposits. These findings suggest that the intricate three-dimensional mesh composed of collagen-coated
fibers substantially augmented the osteogenic activity of human periosteal sheets both in vitro and in vivo. 相似文献
113.
Yuji Yabuki Yoshitaka Mukaida Yoshinori Saito Kazunori Oshima Tatsuo Takahashi Eiichi Muroi Kei Hashimoto Yasushi Uda 《Food chemistry》2010
To characterise the composition of sulphur-containing constituents in Chinese chive (Allium tuberosum Rottler), GC–MS and HPLC analyses were carried out, using 12 varieties of Chinese origin, 4 varieties of Japanese origin and 6 commercially available cultivars. Five disulphides (dimethyl, allyl methyl, methyl 1-(E)-propenyl, diallyl, and allyl 1-(E)-propenyl), two trisulphides (dimethyl and allyl methyl), and two vinyldithiins (3-vinyl-[4H]-1,2- and 2-vinyl-[4H]-1,3-) were identified on the basis of their mass spectral and GC-retention data. Among the detected sulphur compounds, sulphides with a methyl group predominated over those with an allyl group. This was supported by the HPLC estimations, suggesting that all cultivars examined had much greater amounts of methiin than alliin. Also, two novel compounds were tentatively identified as [3H,4H]-1,2-dithiin and [2H,4H]-1,3-dithiin on the basis of their mass spectral features, GC-retention data, and some experimental results on their formation in reaction mixtures with different proportions of methiin and alliin. Their formation mechanism was proposed. 相似文献
114.
115.
A GaAs/AlGaAs directional coupler switch, for the first time with a device length shorter than 1 mm, has been fabricated by utilising the good controllability of molecular beam epitaxy and reactive ion beam etching. The switching voltage is as low as 5V. The extinction ratio is 17dB for a crossover state and 14dB for a straight-through state. 相似文献
116.
Kazuhiro Nagata Katsumi Ohira Hisao Yamada Kazuhiro S. Goto 《Metallurgical and Materials Transactions B》1987,18(3):549-555
The velocity and absorption coefficient of longitudinal ultrasonic waves with 5 and 10 MHz in molten and glassy silicates
and borates have been measured by means of the pulse-echo method in 300 to 1600 K. The silicate and borate were Na2O−SiO2, K2O−SiO2, PbO−SiO2, Na2O−B2O3, and PbO−B2O3. The velocity of sound decreased with increasing temperature and decreased rapidly near the transition temperature of glasses.
The product of the one-third power of velocity of sound and the molar volume of the oxide melt was constant and independent
of temperature. The absorption coefficient of ultrasonic waves in the oxide melts increased with an increase in viscosity.
The absorption mechanisms of ultrasonic waves and the mean free path of phonons in the oxide melts were discussed. 相似文献
117.
T. Hamada R. Morimo A. Takada Y. Yamashita K. Nakayama K. Nagata T. Yuji 《Journal of Materials Processing Technology》2000,100(1-3)
An experimental study has been carried out to investigate the synergistic effect of Ba4CuPt2O9 compounds on the critical current density of fluorine-doped YBCO superconductors. The Ba4CuPt2O9 compounds were synthesized by a solid state reaction. It was found that the synthesis temperature of the Ba4CuPt2O9 compounds was over 800°C, which was higher than that ever reported previously. In addition, the influence of Ba4CuPt2O9 compounds on the critical current density of YBCO superconductors has been investigated using two types of Ba4CuPt2O9 compounds: one is not heat-treated, i.e. source materials; and the other is heat-treated at 950°C. It was found that the former affected the orientation of the c-axes, but the latter did not have an influence on the orientation of the c-axes, but adversely affected the superconductivity of samples quenched at temperatures above 850°C. 相似文献
118.
Jianxin Sheng Tatsuo Fukami Junichi Karasawa 《Journal of the American Ceramic Society》1998,81(1):260-262
An anomalous increase of current with time has been found in iron-doped titania ceramics that have been subjected to a constant field. The result of thermally stimulated current analysis shows a peak at a temperature of 170°–180°C, which increases because of the depolarization of oxygen vacancies. X-ray photoemission spectroscopy indicates that an electrical stress results in an electrochemical reduction inside the specimen, particularly on the cathodic side. These results reinforce the viewpoint that the space charge that is responsible for the anomalous current results from a blockage of the O2 ( g )/O2− ( s ) ion transfer at the cathode. 相似文献
119.
Synthesis of Succinic Gemini Surfactants and the Effect of Stereochemistry on Their Monolayer Behaviors 下载免费PDF全文
Tokuzo Kawase Maiko Kagawa-Ohara Tsunetomo Aisaka Tatsuo Oida 《Journal of surfactants and detergents》2015,18(4):615-627
In this work, succinic gemini surfactants, dl‐ and meso‐2,3‐bis(alkyl)succinic acids (alkyl: C6H13–C13H27), were successfully synthesized by oxidative coupling of enolates of fatty acid tert‐butyl esters with copper(II) bromide followed by treatment with CF3COOH. Focusing on the influence of stereochemistry (dl‐ and meso‐) of succinic geminis, their monolayer behaviors at the air–water interface were explored using surface pressure–area (Π–A) isotherms, the compression modulus of monolayers (εs), and Brewster angle microscope (BAM) analysis. meso‐2,3‐Bis(undecyl)succinic acid showed a unique isotherm where the surface pressure drastically decreased at A = ~0.56 nm2 (Π = 21.9 mN m?1) regardless of compression rates and subphase temperatures, while dl‐isomer showed the common isotherm of gas → liquid‐expanded → liquid‐condensed phase transitions. BAM analysis on meso‐2,3‐bis(undecyl)succinic acid films at the air–water interface showed that small islands of aggregates appear just after the maximum pressure (A = ~0.56 nm2), and on further compression needle‐shaped assemblies appear that can grow in size. It was reasonably concluded that hydrophobic interactions can operate more effectively in meso‐isomers than in dl‐isomers, and that meso‐molecules can “jump up” to cause a transition from monolayer to bilayer. This is the first finding of the “jumping‐up” phenomenon of gemini surfactants having meso‐stereochemistry. 相似文献
120.
Takahiro Mise Shin Tajima Tatsuo Fukano Kazuo Higuchi Tsukasa Washio Kazuo Jimbo Hironori Katagiri 《Progress in Photovoltaics: Research and Applications》2016,24(7):1009-1015
We have investigated the influence of sodium (Na) on the properties of co‐evaporated Cu2ZnSnS4 (CZTS) layer microstructures and solar cells. The photovoltaic performance and diode properties were improved by incorporating Na from NaF layers into the CZTS layers, while Na had a negligible effect on the microstructural properties of the layer. The best cell fabricated by using an optimal CZTS layer (Cu/(Zn + Sn) = 0.70, Zn/Sn = 1.8) yielded an active area efficiency of 5.23%. The analysis of device properties suggests that charge‐carrier recombination at CZTS/CdS interface is suppressed by intentional Na incorporation from NaF layers. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献