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71.
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73.
Internal oxidation was observed in gold-rich alloys as substrates for porcelain veneers in dental restorations, which contain small amounts of Fe and Sn. The internal oxidation proceeded with oxygen ions diffusing to the inner part of the alloy through Fe2O3 formed at the grain boundaries of the alloy matrix. SnO2 was formed internally together with the Fe2O3. The external oxidation zone was composed of only Fe2O3 in a wide range of Fe and Sn concentrations. Fe3O4 was formed with Fe2O3 in the Sn-rich composition range by reduction of Fe2O3 in the presence of Sn. A band mainly composed of SnO2 was formed at the inside of the internal oxidation zone in the composition range where Fe3O4 formed. In the Sn-rich alloys this internal oxidation band of SnO2 moved to the external oxidation zone. 相似文献
74.
Yasuo Harayama 《Nuclear Engineering and Design》1974,31(1):66-71
The effect of radially asymmetric heat generation on the temperature and heat flux distribution in a fuel rod is evaluated. Based on practical assumptions, the temperature distribution in power reactor fuel can be obtained between reasonable limits by solving the steady-state heat conduction equation with asymmetric heat generation. 相似文献
75.
Remineralization effects of xylitol on demineralized enamel 总被引:3,自引:0,他引:3
We morphologically determined the effects of xylitol on the remineralization of artificially demineralized enamel. The samples were demineralized and then immersed in a remineralizing solution with or without 20% xylitol at 37 degrees C for 2 weeks. Samples were observed using contact microradiography, a multipurpose image processor (MIP) and a high-resolution electron microscope (HRTEM). Contact microradiography indicated that remineralization occurred in the surface and deep layers of samples immersed in a non-xylitol solution. Samples immersed in a xylitol solution demonstrated less mineralization in the outer 10 microm of the outermost surface layers, but more mineralization in the middle and deep layers, than was observed in the non-xylitol samples. The MIP evaluation indicated that remineralization was more prominent in layers at depths of 50-60 microm in the xylitol samples than in the non-xylitol samples. Observation of the xylitol samples by HRTEM revealed crystals of various sizes and irregular shapes with unclear crystal angles in the outermost surface layers. In the middle layers, they had thickened and angles of crystals are clear. These results indicate that xylitol can induce remineralization of deeper layers of demineralized enamel by facilitating Ca2+ movement and accessibility. 相似文献
76.
Chunqing?HeEmail author Takenori?Suzuki Eisaku?Hamada Hitoshi?Kobayashi Kenjiro?Kondo Victor?P.?Shantarovich Yasuo?Ito 《Materials Research Innovations》2003,7(1):37-41
Polymer structures have been investigated using positron annihilation lifetime spectroscopy (PALS) with a slow positron beam
as well as a conventional radioactive source (22Na). The properties of the free volume holes near the polymer surface were studied as a function of the positron implantation
energy. The longest lifetime was associated with ortho-positronium (o-Ps) annihilation in the free volume holes. In polytetrafluoroethylene film, the lifetime of o-Ps was observed to decrease with increasing positron implantation depth, and a significant change in the o-Ps lifetime was found at a short distance (about 10 nm) from the surface, while its intensity increased. This result implies
that near the polymer surface the free volume holes become larger that in the bulk. The effect of temperature on the polymer
sub-surface layers was also studied. For high molecular weight polystyrene, the glass transition temperature for the sub-surface
was lower than that for the bulk and thermal expansion coefficient of the sub-surface layers was found to be larger than the
bulk value.
Electronic Publication 相似文献
77.
Junho Cha Yasuo Kuga Akira Ishimaru Sangil Lee 《Antennas and Propagation, IEEE Transactions on》2007,55(2):290-297
A simple steerable array antenna is designed and developed using a movable dielectric phase shifter. The change of effective dielectric constant at different dielectric slab positions on a coplanar waveguide is used as the phase shifter. The impedance matching and desired phase shift conditions are satisfied at two slab heights, and the reflection is designed to be minimized at these slab positions. The low-loss dielectric material is used as the dielectric slab and is placed close to a coplanar transmission line with airgap. The 4times4 steerable array antenna with the phase shifters is designed and fabricated at 20 GHz. The H-plane radiation patterns are measured at different phase shift positions and compared with the expected results 相似文献
78.
Nagase M.. Maruyama T.. Sekine M.. 《Semiconductor Manufacturing, IEEE Transactions on》2007,20(3):245-251
This paper describes an advanced critical dimension (CD) control technology for a 65-nm node dual damascene process and beyond. A newly developed deposition enhanced shrink etching (DESE) process was introduced into both via and trench etching. This technology realizes not only dynamic via shrink ranging 40 nm but also accurate trench CD control by feedforward technology. Etching performance was investigated by electrical results of 65-nm Cu/low-k interconnects using porous chemical-vapor deposition SiOC. The 100% yields of 60-M via chains verified the DESE process robustness. 相似文献
79.
Takuya Otani Kenji Hashimoto Takaya Isomichi Akira Natsuhara Masanori Sakaguchi Yasuo Kawakami 《Advanced Robotics》2013,27(22):1197-1206
In previous studies, various stabilizing control methods for humanoids during the stance phase while hopping and running were proposed. Although these methods contribute to stability while hopping and running, it is possibility that the control during the flight phase could also affect the stability. In this study, we investigated whether the control during the flight phase can affect the stability of a humanoid while running. To achieve stable hopping, we developed a control system that accounts for the angular momentum of the whole body during the flight phase. In this system, the angular momentum generated by the motion of the lower body in each time interval is calculated during the flight phase, and the trunk joints are controlled to generate the angular momentum necessary to compensate for the deviation of the waist posture, which is used as the reference point for the motion coordinate system of the robot. Once the proposed control system was developed and simulated, we found that the hopping duration in the unconstrained state was extended. 相似文献
80.
Nylon-polystyrene microcapsules with immobilized ferroelectric liquid crystalline segments were prepared, and the permeability control of the encapsulated core material was investigated under an external electric field. A ferroelectric liquid crystal monomer possessing both mesogenicity and chirality effectively responded to an external electrical field. Permeation of the material (oxprenolol) contained in the inner aqueous core of the microcapsules was enhanced under a feeble electric field (2 V). Furthermore, it was found that the permeability of the microcapsules without the ferroelectric liquid crystal group did not depend on the external electrical field. In order to clarify the controlled release mechanism of the core material, the transmittance was quantitatively evaluated under an external electric field using a handmade polarized light transmittance apparatus. 相似文献