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81.
82.
Jianliang Deng Xiangxia Zhang Shuilong Shen Junichi Koseki 《Bulletin of Engineering Geology and the Environment》2018,77(3):931-939
To reproduce a subaqueous debris flow with a friction coefficient of approximately tan1° in field, material with a huge volume may be involved. In this research, a steady subaqueous debris flow with a friction coefficient of approximately tan1° was produced by using the rotating flume experiment apparatus (Debris Flow Maker, DFM) with only 40 g of silicon powder. Subsequently, the mechanism of the low friction coefficient was interpreted with the hypothesis of dense agglomeration hitting (DAH). DAH means hitting of the dense agglomeration of dense flow on the flume's bottom plane. The following issues on DAH are considered: (I) the high velocity of the flume's bottom plane induces a strong hitting of particles; (II) the hitting elevates the liquid pressure near the boundary between the agglomeration and the flume's bottom plane; (III) the energy loss due to collision inside the particle agglomeration is limited. The experimental results provide an alternative method of producing subaqueous debris flow and an alternative measurement method of its friction coefficient; the hypothesis provides an alternative interpretation on the mechanism of low friction coefficient of subaqueous debris flow. 相似文献
83.
Shoko Kasuga Ryota Mori Shunichi Kasahara Junichi Rekimoto 《International journal of human-computer interaction》2019,35(15):1345-1351
Growing evidence suggests that the gradual transformation of visuomotor association drives a distinct learning process from abrupt transformation in humans. In the current study, we developed a novel omnidirectional visuomotor transformation paradigm to study details of such difference in more realistic environment than conventional experimental systems. Participants were asked to perform a repetitive three-dimensional (3D) arm-reaching task to a target on a front touch panel, wearing a video see-through head-mounted device that displayed a rotating view of surrounding images. In the abrupt condition, the images were rotated by 20°; in the gradual condition, the rotation was increased in a stepwise-manner from 0° to 20°. In both conditions, pointing errors were decreased after adaptation. Further, although the aftereffect of adaptation was not different between conditions, the speed of decay of the aftereffect, which was quantified by an exponential fit, was slower in the gradual condition, suggesting longer-lasting aftereffects for the gradual shift. 相似文献
84.
Junko Matsuki Tomoko Sasaki Koichi Yoza Junichi Sugiyama Hideo Maeda Ken Tokuyasu 《Journal of Applied Glycoscience》2019,66(4):113
Rice-gel prepared by the following three steps: rice grain cooking, shearing of the cooked rice, and cooling for gel formation, is expected as a novel food ingredient for modification of various food products such as bread and noodles. To meet the demand for high-throughput systems for research and developments on the new rice gels, herein we established a mini-cooking system for preparation of rice gel samples from grains using a small-scale viscosity analyzer (Rapid Visco Analyzer; RVA). Polished rice grains (4 g) were cooked with 22 mL of water in a canister, and the paddle equipped in the canister was rotated at 2,000 rpm for 30 min (80 °C was used as a representative) to shear the cooked rice. The sheared paste was cooled to 10 °C at 160 rpm, and the initial gelation property was evaluated by viscosity analysis within the RVA. Alternatively, the sheared paste was transferred to an acrylic mold and kept at 4 °C for 0, 1, 3, and 5 days for determination of the hardness with a compression test. Compressive forces required to penetrate 20 % thickness for three tested rice cultivars were measured, and the trend of the value shifts during preservation is similar to the corresponding trend obtained in 300-g grain scale laboratory tests, whereas the individual values were halved in the former. This small cooking method could offer a useful assay system for a rapid evaluation in the breeding programs and in the high-throughput screening of additives for the modification of properties. 相似文献
85.
Previous papers have shown ΔKRP to be a useful parameter describing fatigue crack propagation behavior, where ΔKRP is an effective stress intensity factor range corresponding to the excess RPG load (re-tensile plastic zone's generated load) in which the retensile plastic zone appears under the loading process. In this paper, the relationship between ΔKRP and the zone size (
) (which is smaller between the tensile plastic zone at maximum load and the compressive plastic zone at minimum load) was investigated using a crack opening/closing simulation model so as to consider a physical meaning of ΔKRP. As a result, it becomes clear that ΔKRP dominates the zone size
where fatigue damage mostly occurs. This result supports the following crack propagation equationwhere C and m are material constants.Simulation and fatigue crack propagation tests were then carried out for compact tension (CT), center cracked tension (CCT) and four points bend (4PB) specimens under constant amplitude loading to obtain C and m values for HT-50 steel. Fatigue crack propagation tests were also carried out under constant amplitude loading using CCT specimens with residual stress distribution due to flame gas heating at the center line or edge lines. The T specimen introduced tensile residual stress at the tip of a notch, and the C specimen introduced compressive residual stress. It therefore becomes clear that tensile residual stress leads to a decrease in RPG load, while compressive residual stress leads to increase in RPG load, and that the simulation results are in good agreement with the experimental RPG load. It also becomes clear that simulated crack growth curve using the simulated
and the above equation is in good agreement with the experimental curve. It is understood that tensile residual stress creates only a slight increase in crack propagation rate and compressive residual stress create a big decrease a crack propagation rate. 相似文献
86.
SiO2 nanoparticles (NPs) surface modified with polyethyleneimine-oleic acid complex (PEI-OA) has successfully prepared in a simple manner as a stabilizer of metal (Ni) fine particles (FPs) as well as a component of Ni/SiO2 composite particles. Starting from SiO2 NPs which were collected through centrifugation of commercial SiO2 colloids, it was found that PEI-OA can effectively adsorbed on collected SiO2 NPs surface during their redispersion process in toluene with the assistance of ultrasonication. The aggregated particle size (Z-average size) in toluene could be successfully reduced to c.a. 100 nm under saturated adsorption of PEI-OA. It was also found that PEI-OA-modified SiO2 NPs can effectively attach to the Ni FPs by a simple mixing process in toluene. The FE-SEM observation confirmed the adsorption of the PEI-OA-modified SiO2 NPs on the Ni FPs without forming severe NP aggregates. Owing to the attachment of the PEI-OA-modified SiO2 NPs with surfaces that are compatible to toluene and α-terpineol, the suspension stability of the Ni/SiO2 composite particles in these solvents drastically improved. The result was confirmed by the effective reduction of the sedimentation velocity of diluted suspensions as well as by the reduction of the viscosity of dense suspensions. 相似文献
87.
Wave conversion materials with high thermal conductivity are necessary for high-power semiconductor lighting. Ceramics have higher thermal conductivity than existing matrices such as resin or glass in which phosphor particles are dispersed. However, the high densification of ceramics generally requires high-temperature sintering, which degrades and alters the phosphor particles. In this study, we aimed to achieve the high densification of MgO ceramics at room temperature. Applying high hydrostatic pressure with water addition improved the sample packing ratio and promoted the formation of Mg(OH)2. As a result, the relative density was ≥95%. Additionally, various nitride phosphor particles (CaAlSiN3:Eu2+, β-SiAlON:Eu2+, and α-SiAlON:Eu2+) were dispersed in the MgO matrix at room temperature without degrading the luminescence property. The thermal conductivity of the obtained sample was about 8 W m?1K?1, 40 times higher than that of the epoxy matrix. 相似文献
88.
Shape-selective properties of octadecyltrichlorosilane-treated H-ZSM-5, abbreviated as H-ZSM-5-C18, have been observed in the hydrolysis of esters having some rings and lactones in toluene-water solvent system. The shape-selectivity for the reaction has been evaluated by the ratio
of the relative rate constants in comparison with the rate constant of methyl acetate. The selectivity became higher with increase in bulkiness of the substrate. Substrates having the minimum diameter larger than 6.5 Å, significantly larger in size than the pore openings of ZSM-5, could not react in this system. 相似文献
89.
Kazuki Yanome Takayuki Kiba Midori Kawamura Yoshio Abe Kyung Ho Kim Junichi Takayama Akihiro Murayama 《Journal of Electronic Materials》2017,46(7):3873-3879
We report the ellipsometric and photoluminescence (PL) properties of Indium zinc oxide (IZO) films, which were grown by radio frequency sputtering under Ar and O2 atmospheres. IZO films grown under an O2 atmosphere (IZO (O2)) showed enhanced PL properties when compared to the films grown under an Ar atmosphere (IZO (Ar)), particularly with respect to the band-edge emission. The enhancement of band-edge emission can be attributed to the reduction in the non-emissive defect states related to oxygen vacancies, which were repaired by sputtering under O2 atmosphere, whereas the PL enhancement in green region is probably due to the formation of the different types of defects under the excess oxygen environment. This was also supported by the results of time-resolved PL measurements, where the band-edge emission of IZO (Ar) showed rapid decay with a 50 ps lifetime, which indicates the dominance of the relaxation pathway to underlying defect states. In contrast, the PL decay profiles of IZO (O2) for band-edge and emissive defect states showed moderate decay with time-constants of 2.3 ns and 5.7 ns, respectively. The exciton relaxation dynamics were sensitive to the presence and its kinds of defect states, which were controlled by the growth conditions. 相似文献
90.