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排序方式: 共有1721条查询结果,搜索用时 15 毫秒
991.
992.
The aim of this research was to investigate the effect of fish oil supplementation, in the third trimester of pregnancy and
early lactation period of healthy pregnant Danish women. Forty-four pregnant women were randomly allocated to fish oil supplementation
(1.3 g EPA and 0.9 g DHA per day) from week 30 of gestation (FO-group) or to a control regimen (olive oil or no oil; controls).
The FO-group was randomly subdivided into women stopping fish oil supplementation at delivery [FO(pregn)], and women continuing
supplementation for an, additional 30 d [FO(pregn/lact)]. Thirty-six women agreed to collect milk samples at days 4, 16, and
30 postpartum. The FA composition of the milk samples was determined by GLC. At days 4, 16, and 30 in lactation, FO(pregn/lact)
women (n=12) had, respectively 2.3 (P=0.001), 4.1 (P=0.001), and 3.3 (P=0.001) times higher mean contents of LCPUFA(n−3) in their breast milk compared with controls (n=13), and 1.7 (P=0.005), 2.8 (P=0.001), and 2.8 (P=0.001), times higher LCPUFA(n−3) contents, respectively, at these days compared with FO(pregn) women (n=11). The latter group did not differ significantly from controls with regard to LCPUFA(n−3) content in the breast milk. Similar
results were obtained when analyzing separately for effects on the milk content of DHA. Dietary supplementation with 2.7 g
LCPUFA(n−3) per day from week 30 of gestation and onward more than tripled the LCPUFA(n−3) content in early breast milk; supplementation
limited to pregnancy only was much less effective. 相似文献
993.
Yim H Sohn Y 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2000,47(3):549-558
A computer program package has been developed for simulation and visualization of two-dimensional elastic wave propagation and scattering using the mass-spring lattice model (MSLM) and, for comparison, a finite difference model. To assess the reliability of the numerical schemes, their convergence and accuracy have been analysed using the Taylor series expansion and the von Neumann analysis methods. As a result, the grid spacing-time increment combinations previously adopted in the literature have proved to be non-optimal. The optimal combinations have been found and shown to yield the most accurate results with the least computation time, particularly in the high frequency regime. Using these algorithms, a program package has been developed in Visual C++(R) (Microsoft, Redmond, WA) with graphic user interfaces for convenient exploration of visualized results. Numerical results have been obtained for some fundamental problems in ultrasonic testing such as plane waves incident on cracks. All numerical results have shown excellent qualitative agreements with the analytical results of the wave physics, as the reflected, diffracted, head, and Rayleigh waves have been observed. Also, for numerical results with anisotropic media, the cusps on the shear wavefronts have been observed. Finally, slight modification of the modeling method for free surfaces has led to more accurate prediction of Rayleigh waves. 相似文献
994.
Hyoung-Joon Kim Chang-Kyu Chung Yong-Min Kwon Myung-Jin Yim Soon-Min Hong Se-Young Jang Young-Joon Moon Kyung-Wook Paik 《Journal of Electronic Materials》2007,36(1):56-64
The formation of process-related bubbles that become entrapped inside the anisotropic conductive film (ACF) layer during bonding
processes remains an issue. The formation of these bubbles is strongly influenced by the process variables, such as bonding
pressure and bonding temperature. Therefore, bonding process variables of bonding temperature, bonding pressure, and type
of flexible substrate (FS) were changed in order to investigate the effects of the changes as they concern the formation of
bubbles. According to the results, the tendency toward bubble formation was closely related to these three factors. The bubble
area increased as the bonding temperature increased. Moreover, the shape and tendency of bubbles coincided with temperature
distribution in␣the ACF layer. Two different types of FS, each with different surface roughnesses and energies, were used.
The bubbles formed only on the FS with the larger roughness and lower surface energy. According to the results from a surface
energy measurement of FS types using goniometry, a FS with a higher surface energy is favorable for a bubble-free assembly,
as the higher surface energy provides better wettability. In addition, in order to investigate the effect of bubbles on the
reliability of ACF joints, the pressure cooker test (PCT) was performed, and all samples with bubbles electrically failed
after 72 h of a PCT, as the process-related bubbles provided a moisture penetration path and entrapment site for moisture.
However, all type 1 test vehicles (TVs) survived even after 120 h of a PCT. Therefore, Ar and O2 plasma treatments were performed on the FS with the lower surface energy in order to improve the surface energies and wettability.
Following this, the bubbles were successfully removed at rigid substrate (RS)–FS bonding joints using ACFs. 相似文献
995.
Analyses and simulations of the coupled surge-and-heave motions of a nonlinear, moored, experimental, submerged structure subjected to random waves are presented here. The random wave excitations examined include periodic waves with additive noise and narrow-band random waves. Characteristic experimental results include noisy subharmonic and superharmonic responses, and transition behaviors among multiple coexisting responses. This investigation applies a systematic, stochastic analysis procedure to further the deterministic study presented in Part I. Good agreement between the analytical predictions and experimental results is shown. Effects of random perturbations in waves on nonlinear response phenomena are examined, especially for the cases of multiple responses coexisting with chaos. It is found that chaotic responses are sensitive and of weak strength compared to other coexisting responses, and the system response trajectories mainly stay in the stronger, periodic attracting domains. Numerical results indicate perturbation-induced response transitions leading to very large-amplitude response beyond the experimental model limitations. 相似文献
996.
Myung-Jin Yim Kyung-Wook Paik 《Advanced Packaging, IEEE Transactions on》1999,22(2):166-173
The effect of bonding pressure on the electrical and mechanical properties of anisotropic conductive film (ACF) joint using nickel particles and metal-coated polymer ball-filled ACFs was investigated. The contact resistance decreases as the bonding pressure increases. Contact resistance of ACF is determined by the contact area change between particles and contact substrates. Electrical conduction through the pressure engaged contact area between conductive particles and conductor substrates is the main conduction mechanism in ACF interconnection. In addition, environmental effects on contact resistance and adhesion strength such as thermal aging, high temperature/humidity aging and temperature cycling were also investigated. Interestingly, the contact resistances of the excessively bonded samples deteriorated more than those of optimally bonded ones. Increasing contact resistance and decreasing adhesion strength after harsh environmental tests were mainly due to the loss of contact by thermal stress effect and moisture absorption, and also partially due to the formation of metal oxide on the conductive particles 相似文献
997.
998.
Seong Yujin Yim Dami Jang Min Ji Park Jeong Min Park Seong Jin Kim Hyoung Seop 《Metals and Materials International》2020,26(2):221-229
Metals and Materials International - A physics-based constitutive model of porous materials is proposed to enhance the accuracy of numerical analysis in die/isostatic compaction. The correlation... 相似文献
999.
Sung-Dae Yim Young-Jun Sohn Young-Gi Yoon Sukkee Um Chang-Soo Kim Won-Yong Lee 《Journal of power sources》2008
The small PEMFC stack to be integrated with miniaturized fuel reformer is usually operated under very poor operating conditions such as low relative humidity and reformed gas conditions including trace amounts of CO. Hence, for the stable operation of the stack under such real conditions, the effect of reactants feeding method and stack operating conditions such as stack temperature and gas humidity were experimentally investigated and the optimal operating strategy was suggested. 相似文献
1000.
Myoung Youp Song Chang-Dong Yim Jong-Soo Bae Daniel R. Mumm Seong-Hyeon Hong 《Journal of Alloys and Compounds》2008,463(1-2):143-147
Mg–23.5 wt.%Ni–(5, 10 and 15 wt.%)La alloys were prepared by gravity casting and their hydrogen-storage properties were examined after pulverizing. The gravity cast Mg–23.5Ni–(5, 10 and 15)La alloys consist of α-Mg, Mg2Ni and Mg17La2 phases. The activated Mg–23.5Ni–10La alloy has the highest hydrogen-storage capacity of 4.96 wt.%H (from P–C–T curve) and the highest initial hydriding rate (hydrogen content 3.83 wt.%H at 10 min) with an initial hydrogen pressure in the channel of 11 bar H2 at 573 K. This is attributed to its containing the largest amount of the Mg17La2 phase, which is easily dissociable during the hydriding reaction. 相似文献