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排序方式: 共有2683条查询结果,搜索用时 31 毫秒
991.
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994.
Evaluation of long-term durability in high temperature resistant CFRP laminates under thermal fatigue loading 总被引:1,自引:0,他引:1
Thermal fatigue tests were conducted on high temperature resistant carbon fiber reinforced plastics cross-ply laminates to evaluate microscopic damage progress which affects macroscopic mechanical behavior of the laminates. Materials system used were thermoplastic polyetheretherketone based, AS4/PEEK and thermoset bismaleimide based, G40-800/5260. Several types of laminate configuration were used to clarify the effect of ply thickness on microscopic damage progress. Microscopic damages were observed using optical microscopy and soft X-ray radiography. Energy release rate associated with transverse cracking was calculated using variational analysis. The modified Paris law was used to predict transverse cracking. From comparison to mechanical fatigue test results, it is clarified that transverse crack accumulation rate was larger under thermal fatigue loading at same energy release rate range due to the dependence of the fracture toughness on temperature. 相似文献
995.
996.
A three-dimensional (3D) Raman mapping system with a real-time calibration function was developed for detecting stress distributions in solid materials from subtle frequency shifts in Raman spectra. An atomic emission line of neon at 918.3 cm(-1) when excited at 514.5 nm was used as a wavenumber standard. An emission spectrum of neon and a Raman spectrum from a sample were introduced into a single polychromator using a bifurcated optical fiber. These two spectra were recorded simultaneously on a charge-coupled device (CCD) detector using double-track mode. Energy deviation induced by the fluctuation of laboratory temperature, etc., was removed effectively using the neon emission line. High stability during long measurements was achieved. By applying curve fitting, positions of the Raman line were determined with precision of about 0.05 cm(-1). The present system was applied to measurements of residual pressure around mineral inclusions in a natural diamond: 3D stress mapping was achieved. 相似文献
997.
Frédéric Caupin Satoshi Sasaki Sébastien Balibar 《Journal of Low Temperature Physics》2008,150(3-4):267-275
Supersolidity is a rather controversial issue which has been revived recently by a number of torsional oscillator (ac-rotation)
experiments with solid helium 4. One possibility would be that the ground state of helium 4 crystals contains a Bose-Einstein
condensate of mobile vacancies. However, the supersolid signal was shown to depend on sample history. In addition, dc-flow
experiments show that superfluid transport of mass does not occur in solid helium, except if it contains appropriate grain
boundaries. As a consequence, we believe that supersolidity is not an intrinsic property of helium single crystals, but that
it is due to quenched disorder. We report experiments on pressure relaxation in and light scattering from solid samples, that
give additional evidence for the existence of disorder in helium crystals. We also describe our recent study of the wetting
properties of grain boundaries.
相似文献
998.
Satoshi Murakawa Yuichiro Wada Yuta Tamura Masamichi Saitoh Yuki Aoki Ryuji Nomura Yuichi Okuda 《Journal of Low Temperature Physics》2008,150(3-4):154-159
We measured the complex transverse acoustic impedance of superfluid 3He in the B phase by coating a surface with 4He to study the boundary condition dependence of the surface bound states. Observed features in the temperature dependence
were similar to those without 4He coating. However, temperatures showing singularities became higher and variations in the dependence became smaller. The
small variations indicated that a specular surface was realized by the 4He coating. Increase in the singularity temperature indicated that the bandwidth of the surface Andreev bound states became
broader by the coating.
相似文献
999.
Kikuo Tominaga Daisuke Takada Kouji Shimomura Hiroshi Suketa Keisuke Takita Keiichirou Murai Toshihito Moriga 《Vacuum》2008,83(3):561-563
Influence of incorporation of Ga in amorphous In-Zn-O transparent conductive oxide films was investigated as a function of Zn/(Zn + In). For In-Zn-O films with no Ga2O3, the range of Zn/(Zn + In) ratio where the amorphous phase appears became narrow at a substrate temperature of 250 °C. With increasing Ga2O3 quantity, amorphous films were obtained even at a high substrate temperature of 250 °C in a wider range of Zn/(Zn + In) than that of In-Zn-O films with no Ga2O3. This means that the trend of crystallization at higher substrate temperature was disturbed with additional Ga incorporation. For the film deposited from ZnO:Ga (Ga2O3: 4.5-7.5 wt%) and In2O3 targets, we obtained a resistivity of 2.8 × 10−4 Ω cm, nearly the same value as that for an In-Zn-O film with no Ga2O3. The addition of more than 7.5 wt% Ga2O3 induced a widening of the optical band gap. 相似文献
1000.
Wada S Yazawa A Hoshina T Kameshima Y Kakemoto H Tsurumi T Kuroiwa Y 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2008,55(9):1895-1899
Barium titanate (BaTiO3) nanoparticles from 27 to 192 nm were prepared by the 2-step thermal decomposition method from barium titanyl oxalate nanoparticles. These particles were dispersed well into 1-propanol, and dense BaTiO3 nanoparticle sphere arrays without stress-field were prepared by the meniscus method. Temperature dependence of dielectric properties was successfully measured using these dense nanoparticle sphere arrays, and size effect on dielectric properties was discussed. 相似文献