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81.
Keisuke Iizuka Masahito Ueda Takuya Takahashi Akinori Yoshimura Masahiro Nakayama 《Advanced Composite Materials》2019,28(1):73-85
A unidirectional carbon fiber reinforced plastic (CFRP) was scanned by an X-ray computed tomography (CT) system. Based on the X-ray CT images, a three-dimensional model with random fiber waviness was developed. Each fiber location was identified in a sectional CT image. Subsequently, the relative displacement of fibers between adjacent sectional CT images was obtained with a digital image correlation method. This procedure was repeated to obtain fiber waviness along the axial direction. The constructed three-dimensional fiber model showed random waviness of each fiber in the unidirectional CFRP. Finite element analysis was performed using the three-dimensional model. Simulation results showed bending and twisting deformations coupled with axial contractions during axial compression, which developed due to fiber waviness. A reduction of the fiber directional Young’s modulus due to fiber random waviness was quantitatively evaluated. 相似文献
82.
Kazuaki Katagiri Shinya Honda Sayaka Minami Daiki Kimu Shimpei Yamaguchi Takuya Ehiro 《先进材料力学与结构力学》2020,27(18):1541-1550
Abstract The I-shaped cross-sectional beam of CFRP (CFRP I-beam) is usually manufactured by the continuous protrusion method. Carbon fibers can only be arranged in the longitudinal direction. The CFRP I-beam with arbitrary arrangement of carbon fiber was manufactured with applying the electro-activated deposition molding method. The carbon fiber fabric was immersed in the deposition solution and energized, epoxy resin precipitated around carbon fiber and impregnated. The resin-impregnated fabric was installed to the mold, and the CFRP I-beam was fabricated. The CFRP I-beam was subjected to three-point bending tests, and the relationship between load-deflection was simulated by finite-element analysis. 相似文献
83.
Sang-Hyun An Takuya Matsumoto Jun-Ichi Sasaki Hiroyuki Miyajima Ramaswamy Narayanan Satoshi Imazato Kyo-Han Kim 《Materials science & engineering. C, Materials for biological applications》2012,32(8):2516-2522
Anodization is an easily viable technique useful for producing TiO2 coatings on titanium substrates. Nano-crystalline anodic TiO2 structure was produced on titanium at 20 V using 1 M Na2SO4 and 0.5% NaF and consolidated by a further heat-treatment. Micro-crystalline anodic TiO2 was produced on titanium by applying a galvanostatic current density of 70 A/m2 in water medium. To assess the usefulness of these nano- and micro-oxides for bone implant stability, physical properties and bone in vitro bioactivity including HA formation, cellular affinity and mouse-tissue morphogenesis, were evaluated. Bioactivity of the different anodic surfaces was evaluated by treating them in a simulated body fluid (SBF) to form hydroxyapatite (HA) and the rates of HA formation were compared. Deposits of HA could be seen on the nano-oxide surface within 7 days, whereas HA was detected only after 14 days on the micro-oxide surface. In vitro cell culture tests done using mouse osteoblasts indicated that the nano-oxides showed statistically significant cell activity than the micro-oxides and the machined titanium. Branching morphogenesis test done for 72 h on these surfaces showed more branching on the micro- and nano-oxides as compared with titanium surface. 相似文献
84.
Yuya Tachibana Takuya Maeda Osamu Ito Yasukatsu Maeda Masao Kunioka 《International journal of molecular sciences》2009,10(8):3599-3615
We have developed a mulch sheet made by inflation molding of PLA, Ecoflex® and modified starch, which all have different biodegradabilities. A field test of use as an agricultural mulch sheet for mandarin oranges was carried out over two years. The mechanical properties of the mulch sheet were weakened with time during the field test, but the quality of the mandarin oranges increased, a result of the controlled degradation of the sheet. The most degradable modified starch degraded first, allowing control of the moisture on the soil. Accelerator mass spectroscopy was used for evaluation of the biomass carbon ratio. The biomass carbon ratio decreased by degradation of the biobased materials, PLA and modified starch in the mulch sheet. 相似文献
85.
Takatoshi Akase Takuya Ryoke Hiromitsu Kozuka 《Journal of the American Ceramic Society》2009,92(9):1951-1958
Titania gel films were prepared from a coating solution with a starting mole ratio of Ti(OC3 H7 i )4 :H2 O:HNO3 :C2 H5 OH=1:1:0.2:30 on Si(100) wafers by spin coating, with and without sol–gel-derived, fired silica, and titania underlayers. In situ measurement was conducted on the in-plane stress in the titania gel films during heating up to 500°C at 5°C/min. Basically, for all the gel films, the in-plane, tensile stress increases once with increasing temperature, and then decreases around the temperature of crystallization. The increase in stress was thought to result from the capillary pressure due to solvent evaporation and from the densification of the coatings. The reduction in stress around the temperature of crystallization was ascribed to the accelerated atomic diffusion in the coatings and to the difference in thermal expansion coefficient between the coatings and the Si wafer. However, when the stress–temperature curves were examined more in detail, differences were found in the variation in stress, depending on the underlayers. Then, the question of how the underlayers could induce the crystallization and relax the strain in the coatings was discussed. 相似文献
86.
Effect of silver content on thermal fatigue life of Sn-xAg-0.5Cu flip-chip interconnects 总被引:5,自引:0,他引:5
Shinichi Terashima Yoshiharu Kariya Takuya Hosoi Masamoto Tanaka 《Journal of Electronic Materials》2003,32(12):1527-1533
The thermal fatigue properties of Sn-xAg-0.5Cu (x=1, 2, 3, and 4 in mass%) flip-chip interconnects were investigated to study
the effect of silver content on thermal fatigue endurance. The solder joints with lower silver context (x=1 and 2) had a greater
failure rate compared to those with higher silver content (x=3 and 4) in thermal fatigue testing. Cracks developed in the
solders near the solder/chip interface for all joints tested. This crack propagation may be mainly governed by the nature
of the solders themselves because the strain-concentrated area was similar for tested alloys independent of the silver content.
From the microstructural observation, the fracture was a mixed mode, transgranular and intergranular, independent of the silver
content. Higher silver content alloys (x=3 and 4) had finer Sn grains before thermal cycling according to the dispersion of
the Ag3Sn intermetallic compound, and even after the cycling, they suppressed microstructural coarsening, which degrades the fatigue
resistance. The fatigue endurance of the solder joints was strongly correlated to the silver content, and solder joints with
higher silver content had better fatigue resistance. 相似文献
87.
Effects of spraying ozonated water on the severity of powdery mildew infection, visible disorder/injury occurrence, and net photosynthesis in cucumbers were investigated. The severity in the ozonated water treatment was contained to almost the same level throughout the 14-day period of the experiment, while the severity steadily increased in the non-treated control and distilled water treatment. Neither visible disorder/injury on the leaves nor a large difference in net photosynthesis between before and after spraying the ozonated water was observed. The results indicate that ozonated water can be at least a partial alternative to agricultural chemical fungicides for powdery mildew on cucumber leaves. 相似文献
88.
The performance of the multilevel code based high data rate (HDR) codec is evaluated with multiple-symbol differential detection over satellite channels. It is shown that multiple-symbol observation effectively fills the gap between conventional differentially coherent detection and ideal coherent detection with differential encoding. Being especially suitable for HDR application where carrier acquisition and tracking is extremely difficult, the codec reliably supports broadband ISDN transmission over a 72 MHz satellite transponder 相似文献
89.
Keiichirou Yonezawa Alexander Hinderhofer Takuya Hosokai Kengo Kato Rintaro Makino Frank Schreiber Nobuo Ueno Satoshi Kera 《Advanced Materials Interfaces》2014,1(5)
The dependence of the energy level alignment (ELA) on structural defects at an organic/organic heterojunction (OOH) of perfluoropentacene (PFP)‐on‐diindenoperylene (DIP) was investigated using X‐ray scattering and ultraviolet photoelectron spectroscopy. The density of structural defects near the interface between the PFP and DIP layers was varied by changing the growth temperature of the DIP film. A direct relationship was found between the defect density and the ELA at the OOH; the ELA together with the change in the electrostatic potential (quasi‐interface dipole layer) at the OOH varies systematically with the defect density near the interface. This indicates that a key factor affecting the ELA is the electrostatic potential change across the OOH interface, which is produced by electron transfer from DIP occupied gap states to PFP unoccupied gap states. These gap states originate from the defects and are effectively controlled by adjusting the growth conditions of the organic films. As a result, the ELA at OOH interfaces can be controlled by the density of structural defect, which is important for organic devices employing OOHs, such as organic photovoltaic cells. 相似文献
90.
Mitsuru Uesaka Takuya NatsuiKiwoo Lee Katsuhiro DobashiTomohiko Yamamoto Takeshi FujiwaraHaito Zhu Kazuyuki DemachiEiji Tanabe Masashi YamamotoNaoki Nakamura Joichi KusanoToshiyasu Higo Shigeki FukudaMitsuhiro Yoshida Shuji Matsumoto 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,657(1):82-87
We are developing compact X-band linac X-ray sources for nondestructive evaluation and medicine. First, we develop a portable X-ray system by a 950 keV 9.4 GHz X-band linac to realize on-site inspection. We use a low power (250 kW) magnetron as an RF source for compactness of the whole system. Since the RF power source is quite small and the stored energy in the structure is also small, we faced the problem of beam loading and current/RF-power oscillation. We are analyzing the problem by the circuit model. We plan to use this system for erosion inspection of metal pipes of petrochemical complex. By adopting a side-coupling cavity design to avoid the oscillation, we have developed 6 MeV X-band (9.3 GHz) linac for pinpoint dynamic tracking cancer therapy. Furthermore, we are manufacturing 3.95 MeV X-band (9.3 GHz) linac X-ray source with flexible waveguides for on-site bridge inspection. Updated results and situations are presented. 相似文献