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81.
Jeom Kee Paik 《钢结构》2008,23(9):77-77
作为作者系列研究成果[Paik J K.Ultimate strength of perforated steel plates under edge shear loading.Thin-Walled Structures,2007,45:301-6,Paik J K.Ultimate strength of perforated steel plates under axial compressive loading along short edges.Ships Offshore Struct,2007,2(3):(inpress)]的终结篇,与前期论文在边缘剪力或单轴压力荷载方面进行了对比,目的是研究双轴受压和边缘剪力作用下多孔钢板的极限强度特点,这是船舶和船舶型海洋结构在货物和水压作用下的一个典型受力模式。板的约束考虑为四边简支,中心区域为圆形孔。一系列ANSYS非线性有限元分析中考虑了不同的板尺寸(厚度)。在有限元分析基础上,推导出组合荷载下多孔板的极限强度交互关系公式,可用于可靠性分析或规范中极限强度的预测。 相似文献
82.
83.
Jung‐Min Moon Bong‐Soo Kim Hyun‐Jong Paik Jang‐Oo Lee Emiko Mouri Kohji Yoshinaga 《Polymer Engineering and Science》2010,50(6):1067-1074
Silica nanoparticles with well‐defined, highly grafted dense poly(methyl methacrylate) (MMA) were prepared by surface‐initiated activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) of methyl methacrylate with an initiator‐fixed silica particle in the presence of air. Two different polymerizations of MMA were carried out under the same conditions using tris[2‐(dimethylamino)ethyl]amine (Me6TREN) and N,N,N′,N′,N″‐pentamethyldiethylene‐triamine (PMDETA) as the ligand, respectively. In the CuCl2/PMDETA system, polymerization appeared to be more controlled with a lower polydisperisty compared with the CuCl2/Me6TREN system. The monolayer of these particles was formed at the air–water interface using Langmuir‐Blodgett (LB) technique. Multilayers of the particles were fabricated by repetition of LB depositing. A surface pressure–area (π–A) measurement and SEM observation were used to characterize the particle arrays. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers 相似文献
84.
Hwack Joo Lee Hyun Ryu Hyun Min Park Jong Hoo Paik Sahn Nahm Jae-Dong Byun 《Journal of the American Ceramic Society》1998,81(6):1685-1688
Microstructural studies on the interfacial boundaries of 1:1 and 1:2 ordered domains in (Ba0.9 La0.1 )(Mg0.37 Nb0.63 )O3 were conducted using high-resolution transmission electron microscopy and X-ray diffractometry. Both 1:2 and 1:1 ordered domains coexisted in a fully ordered single grain. Each ordered domain occupied its own region, and the interfaces were atomically sharp and coherent. The wavelength of the superlattice modulation was ∼0.47 nm in the 1:1 ordered domain and ∼0.71 nm in the 1:2 ordered domain. The transition from the 1:2 ordered region to the 1:1 ordered region was clearly shown at the interface. These observations well support the structural models that have been previously presented. 相似文献
85.
Backseolgi is a Korean traditional rice cake, which is prepared by steaming the rice flour. After cook-chilling processing, backseolgi samples packaged by a modified atmosphere package (MAP), top sealing package (TSP), and linear low density-polyethylene package
(LDPA; control) were evaluated in regard to microbial safety and sensory characteristics during storage. During storage at
30°C, the cell numbers of aerobic, psychrophilic, and anaerobic bacteria for the MAP sample increased to below 2 log CFU/g
for 10 days, whereas the control and TSP samples increased more than 5.0 log CFU/g after 4 days. After 50 days of storage
at 3°C, the cell numbers in the MAP sample were below 1.0 log CFU/g, whereas they were approximately 3.0 log CFU/g in the
control and TSP samples. In the case of the sensory evaluation, the MAP sample score was above 5.0, whereas the scores of
the CON and TSP samples were 1.0. As a result, MAP was identified as the most effective packaging method for increasing microbial
safety while maintaining the sensory characteristics of the cook-chilled backseolgi. 相似文献
86.
Kyung-Woon Jang Kyung-Wook Paik 《Electronics Packaging Manufacturing, IEEE Transactions on》2009,32(2):74-80
In this paper, the effects of anisotropic conductive film (ACF) viscosity on ACF fillet formation and, ultimately, on the pressure cooker test (PCT) reliability of ACF flip chip assemblies were investigated. The ACF viscosity was controlled by varying the molecular weight of the epoxy materials. It was found that the ACF viscosity increased as the increase of molecular weight of the epoxy materials. However, there was little variation of the thermomechanical properties among the evaluated ACFs with different viscosites. Also, the results showed that the ACFs have no differences in moisture absorption rate, die adhesion strength, and degree-of-cure. In scanning electron microscopy images, the lower ACF viscosity resulted in the smoother ACF fillet shape and the higher fillet height. From the results of PCT, the ACF flip chip assembly with the smoother fillet shape showed better reliability in terms of contact resistance changes. After 130 h of PCT, the flip chip assembly with lower ACF viscosity also showed a lesser degree of delamination at the ACF/chip interface. 相似文献
87.
Sung-Dong Cho Jang K.-W. Jin-Gul Hyun Sangyong Lee Kyung-Wook Paik Hyungsoo Kim Joung-Ho Kim 《Electronics Packaging Manufacturing, IEEE Transactions on》2005,28(4):297-303
Epoxy/BaTiO/sub 3/ composite embedded capacitor films (ECFs) were newly designed for high dielectric constant and low-tolerance (less than /spl plusmn/5%) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of a specially formulated epoxy resin and latent curing agent, and in terms of a coating process, a comma roll coating method is used for uniform film thickness in large area. The dielectric constant of ECF in high frequency range (0.5/spl sim/3 GHz) is measured using the cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. The dielectric constant is calculated by observing the frequencies of the resonant cavity modes. Calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of the epoxy matrix. The dielectric relaxation of barium titanate (BaTiO/sub 3/: BT) powder is not observed within measured frequency. An alternative material for embedded capacitor fabrication is epoxy/BaTiO/sub 3/ composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming a capacitor partially in the desired part. However, the screen printing makes surface irregularities during mask peel-off. Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, a dielectric layer with improved thickness uniformity is successfully demonstrated. Using epoxy/BaTiO/sub 3/ composite ECP, a dielectric constant of 63 and specific capacitance of 5.1 nF/cm/sup 2/ were achieved. 相似文献
88.
89.
AJ Schepers TJ Lam YH Schukken JB Wilmink WJ Hanekamp 《Canadian Metallurgical Quarterly》1997,80(8):1833-1840
The objective of this study was to determine the factors affecting somatic cell count (SCC), to estimate variance components of these factors, and to calculate and evaluate the thresholds for intramammary infection based on SCC. The infection status from 22,467 quarter milk samples from 544 cows in seven herds was determined. Infections status was the most important factor affecting SCC. The increase in SCC was more pronounced for major pathogens than for minor pathogens. Even after adjustment for infection status, the interaction between stage of lactation and parity was significant. For culture-negative samples within a lactation, the shape of the SCC curve was inversely related to the shape of the milk production curve. The shape of the SCC curve was flat for first lactation cows compared with the shape of the SCC curve for cows in subsequent lactations. The effect of clinical mastitis on SCC was significant. The use of SCC thresholds for specific parities and stages of lactation to detect intramammary infection improved quality parameters only slightly over a fixed threshold of 200,000 cells/ml. 相似文献
90.
S R Chae S H Lee J O Kim B C Paik Y C Song H S Park H S Shin 《Water science and technology》2004,49(5-6):257-264
As the sewerage system is incomplete, sewage in Korea lacks easily biodegradable organics for nutrient removal. In this country, about 11,400 tons of food waste of high organic materials is produced daily. Therefore, the potential of food waste as an external carbon source was examined in a pilot-scale BNR (biological nutrient removal) process for a half year. It was found that as the supply of the external carbon increased, the average removal efficiencies of T-N (total nitrogen) and T-P (total phosphorus) increased from 53% and 55% to 97% and 93%, respectively. VFAs (volatile fatty acids) concentration of the external carbon source strongly affected denitrification efficiency and EBPR (enhanced biological phosphorus removal) activity. Biological phosphorus removal was increased to 93% when T-N removal efficiency increased from 78% to 97%. In this study, several kinds of PHAs (poly-hydroxyalkanoates) in cells were observed. The observed PHAs was composed of 37% 3HB (poly-3-hydroxybutyrate), 47% 3HV (poly-3-hydroxyvalerate), 9% 3HH (poly-3-hydroxyhexanoate), 5% 3HO (poly-3-hydroxyoctanoate), and 2% 3HD (poly-3-hydroxydecanoate). 相似文献