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101.
Study of meniscus behavior and surface properties during casting in a high-frequency magnetic field 总被引:6,自引:0,他引:6
Tingju Li Shinji Nagaya Kensuke Sassa Shigeo Asai 《Metallurgical and Materials Transactions B》1995,26(2):353-359
Surface quality of continuously cast metals can be improved by imposing a continuous high-frequency magnetic field from the
outside of a mold. Newly proposed concepts of “soft contacting solidification” and “slow cooling solidification,” which is
tightly related to the mechanism of improving surface quality, were confirmed in model experiments by using molten gallium
and tin. The meniscus motion of the molten gallium accompanied by a mold oscillation and magnetic pressure was measured by
a laser level sensor. The shape variation of a meniscus and the process of ripple formation in an oscillation cycle were directly
visualized by an optical fiberscope camera. Moreover, molten tin was continuously cast and the relationship between the surface
quality and the meniscus motion was studied. A mechanical model for predicting the space between the oscillation marks is
proposed. The casting process using intermittent highfrequency magnetic field was developed. New functions of this field were
investigated regarding the control of initial solidification. It was found that the surface quality of the continuously cast
metal can be improved by the intermittent high-frequency magnetic field as well as the continuous high-frequency magnetic
field.
Formerly Undergraduate Student, Department of Materials Processing Engineering, Nagoya University, 相似文献
102.
K Ishimaru K Nishikawa T Omoto I Asai K Yoshihira K Shimomura 《Canadian Metallurgical Quarterly》1995,40(1):279-281
Two new flavone glucosides, 5,2',6'-trihydroxy-6,7,8-trimethoxyflavone 2'-O-glucoside and 5,2',6'-trihydroxy-6,7-dimethoxyflavone 2'-O-glucoside were isolated from the aqueous methanol extract of the roots of Scutellaria baicalensis. From the extract, seven phenolics, 5,7,2',6'-terahydroxyflavone, 5,7,2',5'-tetrahydroxy-8,6'-dimethoxyflavone, skullcapflavone II, baicalin, baicalin methyl ester, wogonin 7-glucuronide and 3,5,7,2',6'-pentahydroxyflavanone were also isolated. 相似文献
103.
Fukawa M. Kawai T. Okano Y. Sakuma S. Asai S. Kanaoka M. Yamanouchi H. 《Power Delivery, IEEE Transactions on》1996,11(2):627-634
500-kV XLPE-insulated cable with an insulation thickness of 27 mm has been developed for long-distance transmission lines. Basic studies on 500-kV XLPE cable have shown that contaminants in the insulation may be the factor determining electrical performance. This hypothesis is justified by the good correlation obtained between statistical estimations of the size of the largest contaminant in the insulation and the electrical characteristics of full-sized cables. Voltage-withstand and long-term tests have confirmed the design values for minimum breakdown stress, for AC and impulse voltage, and for the degradation coefficients 相似文献
104.
A photolithographic technique was developed that uses 1/10-reduction photoprinting with a phase-shifting mask to make gigahertz SAW devices. Combined with a positive-type resist, this new technique produces IDT electrodes with smaller deviations in width compared with using a negative-type resist. Very sharp 40 nm thick AI electrodes with 0.4 μm lines and spaces were achieved. A 2.5 GHz SAW filter suitable for optical communication systems was developed 相似文献
105.
Kenjiro Terada Mitsuteru Asai Michihiro Yamagishi 《International journal for numerical methods in engineering》2003,58(9):1321-1346
We introduce the finite cover method (FCM) as a generalization of the finite element method (FEM) and extend it to analyse the linear and non‐linear mechanical behaviour of heterogeneous solids and structures. The name ‘FCM’ is actually an alias for the manifold method (MM) and the basic idea of the method has already been established for linear analyses of structures with homogeneous materials. After reviewing the concept of physical and mathematical covers for approximating functions in the FCM, we present the formulation for the static equilibrium state of a structure with arbitrary physical boundaries including material interfaces. The problem essentially involves the discontinuities in strains, and possibly has the discontinuities in displacement caused by interfacial debonding or rupture of material interfaces. We simulate such non‐linear mechanical behaviour after presenting simple numerical examples that demonstrate the equivalence between the approximation capabilities of the FCM and those of the FEM. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
106.
A high-speed InGaAs/InAlAs multiple-quantum-well (MQW) intensity modulator and an InGaAsP/InGaAs MQW distributed feedback laser were monolithically integrated by using a hybrid growth technique combining molecular beam epitaxy and metalorganic vapor phase epitaxy. An operating drive voltage of only 2.0 V, a 20-dB on/off ratio, and a 3-dB bandwidth greater than 15 GHz were obtained. This device operated stably in a single mode and with a side-mode suppression ratio of more than 50 dB 相似文献
107.
Kenichi Asai 《New Generation Computing》2002,20(1):27-51
This paper presents a specializer and a binding-time analyzer for a functional language where expressions are allowed to be
used as both static and dynamic. With both static and dynamic expressions, data structures can be statically accessed while
they are residualized at the same time. Previously, such data structures were treated as completely dynamic, which prevented
their components from being accessed statically. The technique presented in this paper effectively allows data structures
to be lifted which was prohibited in the conventional partial evaluators. The binding-time analysis is formalized as a type
system and the solution is obtained by solving constraints generated by the type system. We prove the correctness of the constraint
solving algorithm and show that the algorithm runs efficiently in almost linear time.
Kenichi Asai, Ph.D.: He is a research associate at the Department of Computer Science, Faculty of Science, the University of Tokyo. He obtained
his bachelors degree, masters degree, and doctor of Science from the University of Tokyo in 1990, 1992, and 1997, respectively.
His research interests are in Programming Languages in general, in Partial Evaluation and Reflection in particular. He is
a member of ACM, IPSJ, and JSSST. 相似文献
108.
A novel low‐power gate driver architecture for large 8 K 120 Hz liquid crystal display employing IGZO technology 下载免费PDF全文
Yasuaki Iwase Akira Tagawa Yohei Takeuchi Takuya Watanabe Satoshi Horiuchi Yoshihiro Asai Kaoru Yamamoto Tohru Daitoh Takuya Matsuo 《Journal of the Society for Information Display》2018,26(5):304-313
A novel low‐power gate driver architecture was developed for large 8 K 120 Hz liquid crystal display panel. For this application, not only high‐speed driving but also low power consumption is required. We employed a high mobility In‐Ga‐Zn‐O, dual VGL level driving method, and gate driver circuit driven by DC supply. The simulation results show that our proposals meet 8 K 120 Hz driving requirements. Also, we have fabricated a prototype panel and confirmed both high‐speed driving and low power consumption. 相似文献
109.
The electrical resistivity of polymer filled with conductive filler, such as carbon black (CB) particles, is greatly decreased by incorporating the conductive filler. This is called the percolation phenomenon and the critical CB concentration is called the percolation threshold concentration (Φ*). For CB particle–filled insulating polymer composite at lower than Φ*, the conductive CB network is constructed in the polymer matrix when the composite is maintained at a temperature higher than the glass‐transition temperature or the melting temperature of the polymer matrix. This phenomenon is called dynamic percolation and the time to reach the substantial decrease in resistivity is called percolation time (tp). To investigate the relationship between the dynamic percolation process and the surface state of CB particles, we used three kinds of carbon black particles such as original carbon black (CB0) and fluorinated carbon black (FCB010 and FCB025)–filled poly(methyl methacrylate) (PMMA). It was observed that the dynamic percolation curves for CB0‐filled PMMA and FCB‐filled PMMA composites shifted to a shorter percolation time with increases in both the annealing temperature and the filler concentration. However, the dynamic percolation curves of FCB‐filled PMMA showed a gradually decreasing trend compared to that of CB0‐filled PMMA composites. The activation energy calculated from an Arrhenius plot of the tp against the inverse of the annealing temperature was decreased by surface fluorine treatment. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1151–1155, 2003 相似文献
110.
The structure and properties of highly stereoregular isotactic poly(methyl methacrylate) (it-PMMA) and syndiotactic poly(methyl methacrylate) (st-PMMA) blends with crystalline stereocomplex formed by supercritical CO2 treatment at temperatures ranging from 35 to 130 °C were investigated by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and dynamic mechanical analysis (DMA) measurements. The melting temperature, Tm, and the heat of fusion, ΔHm, had maximum values at about 200 °C and 25 J/g, respectively. The degree of crystallinity evaluated by WAXD ranged in value from 32 to 38%. The fringed-micellar stereocomplex crystallites were formed in case of treatment temperatures below 90 °C, and the orderliness perpendicular to the helix axis of the fringed-micellar crystallites was considered to be increased with increasing treatment temperature. In case of treatment temperature of 130 °C, the fringed-micellar crystallites and the lamellar crystallites with high orderliness parallel to the helix axis coupled with the perpendicular orderliness were formed, and the respective double endothermic peaks, Tm1 and Tm3, were observed in DSC due to the melting of the two kinds of stereocomplex crystallites. The it-PMMA/st-PMMA blends containing the fringed-micellar crystallites maintained high values of storage modulus, E′, up to higher temperature compared with the amorphous blends. The E′ of the blend treated with CO2 at 130 °C decreased twice at temperatures corresponding to Tm1 and Tm3. 相似文献