• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.05a
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• pp.274-278
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• 2002

The purpose of this study was to characterize the reaction of Cu surface with Cu slurry and CMP performance as a function of additives in CMP slurry. The polish rate of Cu was dependent on the kind of organic acids added in slurry. It was considered that polish rate of Cu was dependent on the concentration of carboxylates and mean particle size. When the etchant and oxidant were added in slurry, the highest removal rate and lower etch rate were measured at neutral pH. The addition of etchant, oxidant and pH adjustor played key roles of CMP ability in slurry. As the pH increased, polish rate of Cu was increased by the enhanced the mechanical effects due to effective dispersion of slurry particles. Alumina abrasives was more desirable for 1st step slurry because of high removal rate of Cu and high selectivity ratio among TaN and Cu.

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.275-289
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• 2002

The objective of this study was to develop an in vitro assessment of sperm fertilizing capacity of bulls and investigate the factors influencing sperm function and characteristics of frozen-thawed bovine spermatozoa. in vitro fertilization (IVF), the evaluation of motility and normal morphology, HOST (hypoosmotic swelling test), Ca-ionophore induced acrosome reaction, luminol and lucigenin-dependent chemiluminescence for the measurement of reactive oxygen species (ROS), the measurement of malondialdehyde formation for the analysis of lipid peroxidation (LPO), and the evaluation of DNA fragmentation using the method of 747-mediated nick end labelling (TUNEL) by flow cytometry were performed in frozen-thawed bovine spermatozoa. Correlations between the rates of fertilization, blastocyst formation after IVF and the values of respective assays were investigated. 1. IVF rate and blastocyst formation rate averaged 64.4% and 34.3% for spermatozoa from high -fertility bull group and averaged 18.5% and 6.2% for spermatozoa from low-fertility bull group, respectively. There were significantly different between two bull groups. Sperm motility and percentage acrosome reaction averaged 79.0% and 66.2% for spermatozoa from high-fertility bull group and averaged 40.7% and 22.9% for spermatozoa from low-fertility bull group, respectivitely. There were not different between two bull groups. 2. Luminol depenent chemiluminescence, LPO and DNA fragementation averaged 6.4, 2.0 nmol and 2.6% from spermatozoa from high-fertility bull group and averaged 6.5, 3.1 nmol and 7.4% for spermatozoa from low-fertility bull group, respectively. There were significantly different between two bull groups. There was no significant difference in lucigenin dependent chemiluminescence between two bull groups. 3. Fertilization rate was positively correlated with motility and the rate of Ca-ionophore induced acrosome reaction, but negatively correlated with the frequency of luminol-dependent chemiluminescence, the rate of LPO, and the percentage of sperm with DNA fragmentation. There was no correlation between fertilization rate and the percentage of swollen spermatozoa, normal morphology, and the frequency of lucigenin-dependent chemiluminescence. 4. Blastocyst formation rate was positively correlated with the rate of Ca-ionophore induced acrosome reaction, but negatively correlated with the frequency of luminol-dependent chemiluminescence, the rate of LPO, and the percentage of sperm with DNA fragmentation. There was no correlation between blastocyst formation rate and motility, the percentage of swollen spermatozoa, normal morphology, and the frequency of lucigenin-dependent chemiluminescence. In conclusion, these data suggest that ROS significantly impact semen quality. The assays of this study may provide a basis fur improving in vitro assessment of sperm fertilizing capacity.

• Journal of Nutrition and Health
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• v.25 no.6
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• pp.492-500
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• 1992

The rate of vitamin K-dependent carboxylation of endogenous liver microsomal proteins and an exogenous peptide substrate for carboxylase were measured to test the effects of excess vitamin A on vitamin K function in rats. In vitro vitamin A incubation in normal rat microsomes of vitamin K-sufficient ras did not influence the carboxylation rates of either endogenous prothrombin precursors or a peptide substrate added, Similarly vitamin A incubation in micro-somes from control and excess vitamin A-fed rats that were on vitamin K-free diet did not change the rate significantly within the respectively groups ; however the rates of endogenous protein carboxylation from excess vitamin A-fed rats tended to be increased by the in vitro vitamin A addition compared to that of control rats. Excess vitamin A-fed rats had 2- to 3- fold higher carboxylase activites of endogenous protein carboxylation either with or without the invitro vitamin A incubation than did control rats. In an in vivo study carboxyalase activites with an added exogenous peptide substrate were not influenced by excess intake of vitamin excess vitamin A-fed rats than for control rats. Carboxylase activites tended to be increased amounts of vitamin A on endogenous protein carboxylation appeareed as early as one week post-initiation of the diet. The results of this study indicate that excess vitamin A produces toxic effect rapidly and that excess dietary vitamin A increase the rate of carboxylation of endogenous protein mainly prothrombin precursors which is an indication of vitamin K defi-ciency.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.1
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• pp.26-32
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• 2007

This study deals with waiting-time dependent backordering rate during stock-out period in the EconomicProduction Quantity (EPQ) model. Assuming that the backordering rate follows an exponentially decreasingfunction of the waiting time, the backorder rate is developed under First-Come-First-Served (FCFS) andLast-Come-First-Served (LCFS) Policy. The mathematical models are developed based on differential equations.Through numerical examples, the validity of the developed models is illustrated.

• Transactions of Materials Processing
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• v.14 no.5 s.77
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• pp.466-472
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• 2005

Inelastic deformation behavior of metals and alloys is considered rate dependent. Uniaxial ratcheting experiments performed by Ruggles and Krempl, and Hassan and Kyriakides exhibited that higher mean stress for a fixed stress amplitude resulted in higher ratchet strain within a rate independent framework and higher stress rate resulted in lower ratchet strain, respectively. These phenomena are qualitatively investigated by numerical experiments through unified viscoplasticity theory. The theory does not separate rate-independent plasticity and rate-dependent creep, and thus uses only one inelastic strain to describe inelastic deformation processes with the concept of the yield surface. The growth law for the kinematic stress, which is a tensor valued state variable of the constitutive equations, is modified to predict the linear evolution of long-term ratchet strain.

• Tunnel and Underground Space
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• v.18 no.3
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• pp.214-218
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• 2008

Dynamic fracturing of anisotropic granite was investigated by SHPB (Split Hopkinson Pressure Bar). Energy absorption during the test and maximum stress were increased as strain rate increased. Maximum stresses in every direction were dependent on the strain rate but not so sensitive to anisotropy. Elastic wave velocity was decreased as strain rate increased and dependent on strain rate in every direction. Especially, elastic wave velocity decreased more rapidly in a strong rock.

• International Journal of Ocean System Engineering
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• v.1 no.4
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• pp.230-235
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• 2011

Reinforced polyurethane foam (RPUF) is one of the important materials of Mark III type insulation systems used in liquefied natural gas (LNG) cargo containment systems. However, RPUF is the most difficult material to use with regard to its safety assessment, because there is little public and reliable data on its mechanical properties, and even some public data show relatively large differences. In this study, to investigate the structural response of the system under compressive loads such as sloshing action, time-dependent characteristics of RPUF were examined. A series of compressive load tests of the insulation system including RPUF under various temperature conditions was carried out using specimens with rectangular section. As a result, the relationship between deformation of RPUF and time is linear and dependent on the loading rate, so the concept of strain rate could be applied to the analysis of the insulation system. Also, we found that the spring constant tends to converge to a value as the loading rate increases and that the convergence level is dependent on temperature.

• Transactions of Materials Processing
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• v.25 no.6
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• pp.359-365
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• 2016

The rate-controlling mechanisms for time-dependent plastic deformation of eutectoid and hyper-eutectoid pearlitic steels at low $T/T_m$ temperatures were explored. The strain rate - stress data obtained from a series of constant load tensile tests at $0.25{\sim}0.30T/T_m$ were applied to the power law, the lattice friction controlled plasticity, and the obstacle controlled plasticity. Of these models, the obstacle controlled plasticity was found to best-describe the rate-controlling mechanism for time-dependent plastic deformation of two steels at low $T/T_m$ temperatures in terms of the activation energy for overcoming the obstacles against dislocation glide in ferrite. The deformed microstructures revealed the dislocation forests of a high density as the main obstacles. In addition, the obstacle controlled plasticity well-explained the effects of cementite on the $0^{\circ}K$ flow stress of two steels.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.468-473
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• 1998

The objective of this paper is to develop a consistent algorithm for the finite element analysis for behavior of concrete under cyclic loading using viscoplastic-damage model. For modeling the behavior of concrete under cyclic loading, consistent algorithms of rate-dependent viscoplastic-damage are employed with a Willam-Warnke 5-parameter failure criterion which can consider the softening behavior of concrete and consistent tangent moduli are derived. Using finite element program implemented with the developed algorithms, the algorithms are verified and the behaviors of concrete under cylic loading are simulated and compared with experimental data.

• Journal of the Korean Chemical Society
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• v.48 no.6
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• pp.663-666
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• 2004