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排序方式: 共有706条查询结果,搜索用时 15 毫秒
631.
Microstructural Characterization of Porous Silicon Carbide Membrane Support With and Without Alumina Additive 总被引:1,自引:0,他引:1
Manabu Fukushima You Zhou Hiroyuki Miyazaki Yu-ichi Yoshizawa Kiyoshi Hirao Yuji Iwamoto Satoshi Yamazaki Takayuki Nagano 《Journal of the American Ceramic Society》2006,89(5):1523-1529
Porous silicon carbide (SiC) membrane supports sintered at 1500°–1800°C were prepared by cold isostatic pressing (CIP) under different pressures and using different amounts of alumina additive (0%–4%). The relationship between processing factors and pore size and microstructure was examined. Varying the sintering temperature, the CIP pressure and the amount of additive used were found to be effective for controlling pore size and microstructure. The pore size and particle size of the membrane support prepared without alumina were found to increase with increasing sintering temperature. This was attributed to surface diffusion. Densification of the undoped support did not occur, however, because of concurrent pore development. In the SiC membrane support containing 4% alumina, small particles and a pore size of around 100 nm were retained. This was because of the formation of a limited amount of SiO2 –Al2 O3 liquid phase during sintering. 相似文献
632.
Vibration characteristics of laminated composite plates with embedded shape memory alloys 总被引:1,自引:0,他引:1
Run-xin Zhang Qing-Qing Ni Arata Masuda TakahikoYamamura Masuharu Iwamoto 《Composite Structures》2006,74(4):389-398
Shape memory alloy (SMA) is commercially available for a variety of actuator and damping materials. Recently, SMA wires have also become commercially available for the design of smart composite structures because SMA wires with a small diameter can be easily produced. In this work, two types of SMA-based composites are presented for investigating the vibration characteristics. First, laminated composite plates containing unidirectional fine SMA wires are fabricated. By measuring the vibration mode of a clamped cantilever, the influence of both SMA arrangement and temperature on the vibration characteristics is made clear. Next, laminated composite plates with embedded woven SMA layer are fabricated. The stiffness tuning capability is evaluated by impact vibration tests with different temperatures. It is found that the stiffness tuning capability may be improved by increasing the volume fraction of SMAs and by controlling accurately the internal stress according to the phase transformation temperature of SMAs from martensite to austenite. The theoretical prediction on the natural frequency considering the SMAs behavior and laminated structures is proposed and their results agree reasonably with experimental ones. 相似文献
633.
Yusuke Daiko Kyohei Segawa Kodai Machida Hiroaki Imataka Sawao Honda Yuji Iwamoto 《Advanced Engineering Materials》2018,20(9)
634.
Osamu Takeda Hirone Iwamoto Ryota Sakashita Chiaki Iseki Hongmin Zhu 《International Journal of Thermophysics》2017,38(7):109
A surface tension measurement method based on the maximum bubble pressure (MBP) method was developed in order to precisely determine the surface tension of molten silicates in this study. Specifically, the influence of viscosity on surface tension measurements was quantified, and the criteria for accurate measurement were investigated. It was found that the MBP apparently increased with an increase in viscosity. This was because extra pressure was required for the flowing liquid inside the capillary due to viscous resistance. It was also expected that the extra pressure would decrease by decreasing the fluid velocity. For silicone oil with a viscosity of \(1000\,\hbox {mPa}{\cdot }\hbox {s}\), the error on the MBP could be decreased to +1.7 % by increasing the bubble detachment time to \(300\,\hbox {s}\). However, the error was still over 1 % even when the bubble detachment time was increased to \(600\,\hbox {s}\). Therefore, a true value of the MBP was determined by using a curve-fitting technique with a simple relaxation function, and that was succeeded for silicone oil at \(1000\,\hbox {mPa}{\cdot } \hbox {s}\) of viscosity. Furthermore, for silicone oil with a viscosity as high as \(10\,000\,\hbox {mPa}{\cdot }\hbox {s}\), the apparent MBP approached a true value by interrupting the gas introduction during the pressure rising period and by re-introducing the gas at a slow flow rate. Based on the fundamental investigation at room temperature, the surface tension of the \(\hbox {SiO}_{2}\)–40 \(\hbox {mol}\%\hbox {Na}_{2}\hbox {O}\) and \(\hbox {SiO}_{2}\)–50 \(\hbox {mol}\%\hbox {Na}_{2}\hbox {O}\) melts was determined at a high temperature. The obtained value was slightly lower than the literature values, which might be due to the influence of viscosity on surface tension measurements being removed in this study. 相似文献
635.
Direct estimation of class membership probabilities for multiclass classification using multiple scores 总被引:1,自引:1,他引:0
Kazuko Takahashi Hiroya Takamura Manabu Okumura 《Knowledge and Information Systems》2009,19(2):185-210
Accurate estimation of class membership probability is needed for many applications in data mining and decision-making, to
which multiclass classification is often applied. Since existing methods for estimation of class membership probability are
designed for binary classification, in which only a single score outputted from a classifier can be used, an approach for
multiclass classification requires both a decomposition of a multiclass classifier into binary classifiers and a combination
of estimates obtained from each binary classifier to a target estimate. We propose a simple and general method for directly
estimating class membership probability for any class in multiclass classification without decomposition and combination,
using multiple scores not only for a predicted class but also for other proper classes. To make it possible to use multiple
scores, we propose to modify or extend representative existing methods. As a non-parametric method, which refers to the idea
of a binning method as proposed by Zadrozny et al., we create an “accuracy table” by a different method. Moreover we smooth
accuracies on the table with methods such as the moving average to yield reliable probabilities (accuracies). As a parametric
method, we extend Platt’s method to apply a multiple logistic regression. On two different datasets (open-ended data from
Japanese social surveys and the 20 Newsgroups) both with Support Vector Machines and naive Bayes classifiers, we empirically
show that the use of multiple scores is effective in the estimation of class membership probabilities in multiclass classification
in terms of cross entropy, the reliability diagram, the ROC curve and AUC (area under the ROC curve), and that the proposed
smoothing method for the accuracy table works quite well. Finally, we show empirically that in terms of MSE (mean squared
error), our best proposed method is superior to an expansion for multiclass classification of a PAV method proposed by Zadrozny
et al., in both the 20 Newsgroups dataset and the Pendigits dataset, but is slightly worse than the state-of-the-art method,
which is an expansion for multiclass classification of a combination of boosting and a PAV method, on the Pendigits dataset.
相似文献
Manabu OkumuraEmail: |
636.
Mikio Koyano Syuu Horisaka Hiroshi Negishi Minoru Sasaki Masasi Inoue Naoshi Suzuki Kazuko Motizuki 《Journal of Low Temperature Physics》1990,78(1-2):141-154
Galvanomagnetic measurements on layer-structured 3d transition-metal intercalates of MxTiS2 (M = Mn, Fe, Co, and Ni;x0.33) have been made over the temperature range 0.34–20 K. Resistivity minima and negative magneto-resistances are observed for paramagnetic Mn, Fe, and Ni intercalates with low guest concentrations (x0.1), as found in well-known dilute alloys. However, in the case of the weak-ferromagnetic phase of CoxTiS2 (0.10x0.33) with the Curie temperatureT
c
=120–140 K, such anomalous behaviors are also observed, which is not commonly found in the magnetically ordered phases of various magnetic materials. With these data we have given qualitative discussions on the magnetic scattering process of conduction carriers. Further, some of the experimental results are discussed in connection with the band calculations for M1/3TiS2. 相似文献
637.
Shinobu Hashimoto Tomoya Umeda Kiyoshi Hirao Naoki Kondo You Zhou Hideki Hyuga Sawao Honda Yuji Iwamoto 《Journal of the European Ceramic Society》2013,33(1):61-66
A novel technique for the fabrication of porous ZrO2 with a high volume fraction of fine closed pores was investigated. A partially stabilized ZrO2 (3 mol% Y2O3; Y-PSZ) body, with a 97–99% relative density and containing a small amount of impurities, exhibited a large volume expansion related to the formation of closed pores after heating at 1700 °C for 10 min in N2. These closed pores seemed to mainly form due to the vaporization of hydroxyl apatite: Ca10(OH)2(PO4)6 as an impurity and superplasticity of the ZrO2 during heating. Porous ZrO2 with approximately 24.6% closed pores (total porosity: 26.7%) was successfully fabricated by the addition of 1 mass% SiO2, 1 mass% TiO2, and 1 mass% hydroxyl apatite. The closed pore size and morphology of the resultant porous ZrO2 bodies were investigated, and the formation mechanism of the closed pores was examined on the basis of chemical thermodynamics. 相似文献
638.
Si-doped titanias with a Si/Ti charged ratio of 0.2 was prepared by thermal reactions of titanium tetraisopropoxide and tetraethyl
orthosilicate in 1,4-butanediol at 300 °C (glycothermal reaction) and N- and Si- co-doped titanias were prepared by heating
the thus-obtained Si-doped titanias in an NH3 flow. N- and Si- co-doped titanias had a stronger absorption in a visible light region of 400–550 nm, and exhibited high
photocatalytic activities for decomposition of acetaldehyde under visible-light irradiation. In this study, N- and Si- co-doped
titanias were further modified with vanadium by an impregnation method using an ammonium vanadate solution, and the obtained
catalysts were characterized by XRD, BET surface area measurement, UV-vis, and ESR. Photocatalytic decomposition of acetaldehyde
using the V-loaded N- and Si- co-doped titanias was examined and it was demonstrated that a very small amount of V-loading
(V/Ti = 0.0001–0.001) significantly enhanced the photocatalytic activity under visible-light irradiation. 相似文献
639.
A scanning ion-conductance microscope (SICM) with a vibrating probe has been recently developed (vSICM). In this system, the amplitude of the AC ionic current is detected by using a lock-in amplifier locked to the vibration frequency of the probe. Such a scheme allows for a better control of the tip position because the AC ionic current is more sensitive to the probe-surface distance than the DC ionic current used previously. In this paper, we demonstrate the utility of this technique to the imaging of topographically rough specimens and high-resolution imaging over selected small areas. We also show that it is possible to record the DC ionic current simultaneously during the scan, which can reveal additional information not apparent in the images obtained with the AC ionic current. 相似文献
640.
We have reacted diaminomaleonitrile with pyruvic aldehyde or pyruvic acid to produce 2, 3-dicyano-5-methylpyrazine and 2, 3-dicyano-6-hydroxy-5-methylpyrazine. Although these compounds showed no fluorescence, condensation with arylaldehyde yielded red to violet coloured styryl-type dyes with strong orange to red fluorescence. We have investigated the tautomerism and fluorescent properties of these new pyrazine dyes by means of computer simulation, and have also investigated their spectral properties using molecular orbital and molecular mechanics calculation techniques. These studies revealed the dyes to have strong intramolecular charge-transfer chromophoric systems and high solvatochromism both in absorption and fluorescence spectra. 相似文献