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131.
Toru Nagaoka Yoshiaki Morisada Masao Fukusumi Tadashi Takemoto 《Metallurgical and Materials Transactions B》2010,41(4):864-871
To obtain sound butt-joints of 5056 aluminum alloy rods, ultrasonic-assisted soldering was conducted using Zn-18Sn and Zn-60Sn
alloys. Each solder foil was inserted between rods of 5056 aluminum alloy. Ultrasonic vibration was propagated to faying surfaces
at soldering temperatures below the liquidus temperature of the solder alloys, and then the samples were air cooled to room
temperature. The optimum vibration time at the soldering temperature must be more than 2 seconds to have complete wetting
and less than 4 seconds to avoid excessive dissolution of the 5056 alloy. The 5056 alloy joints soldered using quasi-melting.
Zn-Sn alloys showed greater strength than the joints soldered at the temperatures over its respective liquidus temperature.
As the soldering temperature was increased, the increased formation of the intermetallic compound Mg2Sn or phases containing Mg generated by dissolution of 5056 into the solder layer decreased the joint strength. Ultrasonic-assisted
soldering at an optimum temperature between solidus and liquidus of the Zn-Sn alloys is an important consideration for producing
sound joints with sufficient strength. 相似文献
132.
Molecular weight dependence of growth and morphology of spherulites of isotactic poly(butene-1), iPB-1, and those of the mixtures with atactic poly(butene-1), aPB-1, were examined by atomic force microscopy (AFM) and polarizing optical microscopy (POM) in order to examine the mechanism of the structural evolution by the branching and re-orientation of lamellar crystals at the growth front. The width of lamellar crystals and the characteristic size of the inner structure of spherulites decreased with increasing molecular weight. The result suggests that the mobility of the melt determines the sizes in spherulites and supports the growth front instability induced by a gradient triggering the branching. The sizes in the mixtures also decreased with increasing weight-averaged molecular weight, Mw. The size dependence in low Mw region, however, was too strong and that in high Mw was too weak in comparison with the predicted dependence for the prepared Mw. It has been concluded that the peculiar behaviors should be discussed with effective Mw influenced by the occurrence of separation and exclusion of non-crystallizing aPB-1 at the growth front. 相似文献
134.
In this paper, the problem of estimating the parameters of an FIR system from only the fourth-order cumulants of the noisy system output is considered. The FIR system is driven by a symmetric, independent, and identically distributed (i.i.d) non-Gaussian sequence. We propose a new formula called Weighted Overdetermined C(q, k) (WOC(q, k)) by extending the conventional C(q, k) formula. The optimal selection of the weights in WOC(q, k) is performed by using the Genetic Algorithm (GA) optimization method which minimizes a nonlinear error function based on the fourth-order cumulants alone. Simulations are provided to reveal the effectiveness and the superiority of this novel technique over the C(q, k) and other existing techniques. 相似文献
135.
Xin-Tong Zhang Hong-Wu Liu Taketo Taguchi Qing-Bo Meng Osamu Sato Akira Fujishima 《Solar Energy Materials & Solar Cells》2004,81(2):197-203
Al2O3-coated TiO2 porous films were used to fabricate solid-state dye-sensitized solar cells using CuI as hole conductor. Investigation with transient photovoltage measurements showed that the Al2O3 interlayer slowed down the interfacial recombination of electrons in TiO2 with holes in CuI by forming a potential barrier at the TiO2/CuI interface. As a consequence, the cell made from Al2O3-coated TiO2 film showed superior cell performance than the cell made from TiO2 film only, especially under relative high intensity of simulated sunlight. 相似文献
136.
Tohru Sugiyama Yoshiaki Kudo Youichi Takayama 《Journal of the Society for Information Display》2009,17(1):29-35
Abstract— Soft proofing, which can confirm the color reproduction of printed matter on a monitor, is coming into wide use in the field of graphic arts. However, there is a problem in that the color on the monitor looks different from that of printed matter, even though the L*a*b* value of the monitor's white point has been adjusted to that of the paper by using a spectroradiometer. After the color rendition of an LCD is visually adjusted to that of the paper, the measured color of the LCD shows color with L*a*b* values corresponding to a more greenish‐blue white than that of paper. For CRTs, this corresponds to a more bluish‐white. In this paper, it was assumed that bright lines in the measured spectrums of the monitors and the illuminations spread to the next wavelength band by the optical systems of the spectroradiometer. To solve the problem, a method is proposed to enhance the bright line by using a three‐tap digital filter. The effect of this method on two types of monitors under three types of illumination is also reported. After enhancing the bright lines, ΔE between the monitor and paper becomes smaller than that for the original one. 相似文献
137.
By an immunomagnetic-bead (IMB) separation technique, isolation of Helicobacter pylori from gastrointestinal and fecal samples of gnotobiotic mice infected with the microorganism was tried. The isolation rate of H. pylori from stomach samples after IMB separation was not higher than that of direct culture of the samples. After IMB separation of feces, H. pylori was detectable by PCR, although H. pylori was not culturable. 相似文献
138.
Our newly developed “barrel-sputtering” technique has been employed for the surface coating of solid substrates with complex shapes such as bolts, nuts, and screws. The entire surface of the iron bolts and nuts including the flank and the root in the thread is homogeneously coated with the Au film. SEM measurements reveals that the surface of the Au film is very smooth. In the SEM measurements of the cross-sectional area, it is found that the Au film possess uniform thickness without any significant defects and/or pits. The Au film coating can also be successfully conducted on polycarbonate bolts and small SUS screws. The results provide evidences that the sputter deposition takes place in “three-dimensionally.” 相似文献
139.
Toyoaki MatsuuraMasaaki Sugiyama Masahiko Annaka Yoshiaki HaraTeruo Okano 《Polymer》2003,44(16):4405-4409
The shrinking mechanism of comb-type grafted poly(N-isopropylacrylamide) gel was investigated by small-angle X-ray scattering (SAXS). The SAXS reveals that the microdomain structure with characteristic spacing of 460 Å is developed in the comb-type grafted poly(N-isopropylacrylamide) gel during the shrinking process. These observations suggest that the freely mobile characteristics of the grafted chains are expected to show the rapid dehydration to make tightly packed globules with temperature, followed by the subsequent hydrophobic intermolecular aggregation of the dehydrated graft chains. The dehydrated grafted chains created the hydrophobic cores, which enhance the hydrophobic aggregation of the networks. These aggregations of the NIPA chains contribute to an increase in void volume, which allow the gel having a pathway of water molecules by the phase separation. 相似文献
140.
Yuri Yamazaki Kyoko Kohno Dr. Hiroyuki Yasui Prof. Yoshiaki Kiso Prof. Miki Akamatsu Prof. Benjamin Nicholson Dr. Gordafaried Deyanat‐Yazdi Dr. Saskia Neuteboom Dr. Barbara Potts Dr. G. Kenneth Lloyd Dr. Yoshio Hayashi Prof. 《Chembiochem : a European journal of chemical biology》2008,9(18):3074-3081
NPI‐2358 ( 1 ) is a potent antimicrotubule agent that was developed from a natural diketopiperazine, phenylahistin, which is currently in Phase I clinical trials as an anticancer drug. To understand the precise recognition mechanism of tubulin by this agent, we focused on its potent derivative, KPU‐244 ( 2 ), which has been modified with a photoreactive benzophenone structure, and biotin‐tagged KPU‐244 derivatives ( 3 and 4 ), which were designed and synthesized for tubulin photoaffinity labeling. Introduction of the biotin structure at the p′‐position of the benzophenone ring in 2 exhibited reduced, but significant biological activities with tubulin binding, tubulin depolymerization and cytotoxicity in comparison to the parent KPU‐244. Therefore, tubulin photoaffinity labeling studies of biotin‐derivatives 3 and 4 were performed by using Western blotting analysis after photoirradiation with 365 nm UV light. The results indicated that tubulin was covalently labeled by these biotin‐tagged photoprobes. The labeling of compound 4 was competitively inhibited by the addition of diketopiperazine 1 or colchicine, and weakly inhibited by the addition of vinblastine. The results suggest that photoaffinity probe 4 specifically recognizes tubulin at the same binding site as anticancer drug candidate 1 , and this leads to the disruption of microtubules. Probe 4 serves well as a useful chemical probe for potent antimicrotubule diketopiperazines, much like phenylahistin, and it also competes for the colchicine‐binding site. 相似文献