• Proceedings of the KSME Conference
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• 2003.04a
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• pp.358-363
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• 2003

Spot welded structure is operated in diverse situation because of temperature, humidity and precipitation. In addition factors of environmental pollution such as acid rain, that courses corrosion, have the tendency to increase, But spot welded structure strength is affected by dampness and environment temperatures. Therefore, it is important to evaluate effect of temperature of spot welded part, In this study, the strength distribution of spot welded plates is evaluated about the environmental temperature of zine coated steel plates and test is conducted with welded part immersed in distilled and synthetic sea water. Specimens are immersed into water for 10, 100, 500 and 1000hours to evaluate the effects of water immersion time on tensile-shear strength under the conditions of -40, 0, 20 and $50^{\circ}C$. Strength is evaluated by tensile-shear test. The conditions of spot welding are 240kgf electrode force, 10KA welding current with 0 and 5mm clearance. From this study, spot welded specimens with clearance have lower tensile-shear strength in the distilled water or synthetic sea water comparing with spot welded specimens without clearance. And they have lower tensile-shear strength under $-40^{\circ}C$ and over $50^{\circ}C$.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.537-544
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• 2003

This paper deals with stress corrosion cracking behavior of high strength steel exposed to marine environments. The objective is to determine the time to failure as a function of hydrogen concentration and tensile stress in the wires. A crack growth curve is modeled using finite element method (FEM) program. The coupled hydrogen diffusion-stress analyses of SCC were programmed separately. The first part is calculating stress and stress intensity /sup 1)/factor of a cylindrical shell, prestressing tendon or suspension bridge wires, from the initiation of cracks to rupture. Virtual crack extension method, contour integral method, and crack tip elements are used for the calculation of stresses in front of the crack tip. Comparisons of the result show a good agreement with the analytical equations and wire tests. The second part of the study deals with the programming of hydrogen diffusion, affected by hydrostatic stress, calculated at the location of boundary of plastic area around the crack tip. The results of paper can be used in the design and management of prestressed structures, cable stayed and suspension bridges. Time dependent correlated parallel reliabilities of a cable, composed of 36 wires, were evaluated by the consideration of the deterioration of stress corrosion cracking.

• Journal of the Korean Solar Energy Society
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• v.34 no.4
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• pp.91-99
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• 2014

The purpose of the study is to apprehend the preference of occupants to colors and installation locations for DSC combined windows and doors, and suggest a concept to optimize the design and function of windows and doors. A miniature model was made applying green, blue, and red colored DSC windows and doors to survey preference about DSC colors and applied location. And a survey was accomplished to 140 subjects by showing pictures of the model and the result of the survey became the basis for suggesting a concept to design DSC integrated windows and doors. Through the survey, blue color and upper part were chosen as the highest level of satisfaction in the situation of external brightness and residence. On the contrary to this, red color was chosen as the lowest level of preference when applied to both of upper and lower parts of winders and doors. Therefore, it's expected that, if various patterns of texture are developed for blue colored DSC, and installation is arranged based on upper part of windows and doors where lighting condition and comfort are less affected, then, conditions of brightness, view, and residents satisfaction will be equally fulfilled.

• Korean journal of applied entomology
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• v.17 no.3 s.36
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• pp.139-142
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• 1978

Activities of several hydrolytic enzymes in the rusted pear loaves were estimated. Tested enzymes were cellulase (Cx), invertase $\beta-amylase$, pectinase (pectinmethylesterase and polygalacturonase), and phosphatase. Enzyme activities represented by pH value-enzyme activitycurve. Activities of Cx. invertase. and $\beta-amylase$ were higher in the healthy part than those in the near-lesion and lesion parts. and showed the maximal activities around pH 7.0. On the other hand, activities of pectinase and phosphatase were higher in the lesion and near-lesion parts than in the healthy part. Pectinmethylesterase activities in the healthy and diseased parts were different with different curve-pattern as the pH of treating solution changed.

• Journal of Plant Biology
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• v.13 no.1
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• pp.56-64
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• 1970

The present experiments differning from that conducted by agriculturists with the first consideration of food or seed production were performed in order to investigate the density effect on dry matter production in the artified population of maize. Three experimental plots were established and one seed was sown in the first plot, 2 seeds in the second plot and 3 seeds in the third plot, respectively. The space of each ridge was designed with 30cm in width and 50cm in length. The space of each seed was 4cm and the growth amount by density was measured through three times. The results obtained are as follows: 1) The total growth amount per unit area was in the order of the third, second and first plots until the second sampling. At the third sampling the whole plots showed almost the same growth amount except the first plot which showed a slightly smaller amount. 2) The growth amount per individual plant was in the order of the third, second and first plots until the second sampling, while the first plot showed drastic growth compared with the other two plots at the third sampling. 3) The growth amount by each organ(leaf, stem and root) of the plant body was markedly abundant in the stem of the non-productive part compared with that in the leaf of the productive part. Especially the root was affected remarkably by density and the first plot showed an abundant growth in comparison with the other plots which were too poor to resist the gound surface.

• Journal of the Korean Society of Food Culture
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• v.10 no.3
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• pp.175-184
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• 1995

The awareness of the nutrition labeling of 82 food producers and 668 government officials was assessed and compared, from May to June in 1994, to that of consumers. Compared to 82.4% of cosumers, 48.1% of producers and 47.8% of officials answered that nutrition labeling is necessary. 48% of producers expected a modest food price rise, but 70% thought food sales would not be affected with nutrition labeling. While being worried about the regulatory difficulties and the increased work load given the inadequate implementation of the current food labeling system due to insufficient personnel, 50.2% of officials wanted the new nutrition labeling system to be introduced within $1{\sim}2$ years. Contrary to the general dissatisfaction with the system and the lack of confidence in it on the part of consumers, producers thought that they currently provide sufficient food information for consumers, and that consumers had much confidence in it. Producers and officials were more found worried about consumers' inadequate understanding and inactive use of the system in contrast to the widespread and welcome support on the part of consumers. But it was fully agreed by all that education and awareness is crucial for the successful implementation of nutrition labeling system.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.4 s.112
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• pp.32-37
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• 2005

To Increase the productivity of a paper machine, the maximization of the machine speed is a kind of simple way As the machine speed increases, more intense wet pressing is required to persist the outlet consistency of press part and reduce the water removal of dryer part. With more intense pressing, there are concerns that the quality of paper will be affected. This study was carried out to evaluate the influence of wet-pressing on internal structure of paper, The nip pressure at the first and third nip in triple nip press was controlled. Paper structures, strength properties and pore properties were evaluated. As a result, first nip pressure more strongly influenced the paper structural properties than third nip pressure in triple nip pressing condition. Because of the high water content and low wet-web strength of paper web in first nip, increasing the first nip pressure induced the incipient crushing of wet-web and then caused a potential of web break during the following coating or printing processes.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.64-71
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• 2005

The welding methods have been applied to the most structural products used in the automobile, ship construction, and construction. The structure steel must have sufficient strength of structure; However, the mechanical properties of the welded part changes when it is welded. Therefore, the stability or life of the structure may be affected by the changed mechanical properties. The mechanical properties of the welded part must be examined in order to ensure the safety of structure. In this research, the SS400 steel and the STS304 steel were used to estimate the mechanical properties of the HAZ by weld thermal cycle simulation. In this study, the materials were used to examine the weld thermal cycle simulation characteristic, under two conditions: the drawing with diameter of $\Phi$10 and the residual stress removal treatment. To examine the mechanical properties by the weld thermal cycle simulation, the tensile test was carried out in room temperature. The crosshead speed was lmm/min.

• Journal of Welding and Joining
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• v.19 no.1
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• pp.65-74
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• 2001

A study on the corrosion behavior in case of As-welded and PWHT temperature 55$0^{\circ}C$ of welding part of RE36 steel for marine structure was investigated with parameters such as micro-Vickers hardness, corrosion potential measurement of weld metal(WM), base metal(BM) and heat affected zone(HAZ), both Al anode generating current and Al anode weight loss quantity under sacrificial anode cathodic protection conditions. And also we carried out slow strain rate test(SSRT) in order to research both limiting cathodic polarization potential for hydrogen embrittlement and optimum cathodic protection potential as well as mechanical properties by post-weld heat treatment(PWHT) effect. Hardness of HAZ was the highest among three parts(WM, BM and HAZ) and the highest galvanic corrosion susceptibility was HAZ. And the optimum cathodic polarization potential showing the best mechanical properties by SSRT method was from -770mV to -875mV(SCE). In analysis of SEM fractography, applied cathodic potential from -770mV to -875mV(SCE) it appeared dimple pattern with ductile fracture while it showed transgranular pattern (Q. C : quasicleavage) under -900mV(SCE). However it is suggested that limiting cathodic polarization potential indicating hydrogen embrittlement was under -900mV(SCE).

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.510-513
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• 2012

Palladium particles were synthesized by conventional chemical reduction method with ionic liquids. The size and shape of palladium particles were significantly affected by the cation parts of ionic liquids. This is mainly attributed to the different stabilities of the ionic liquid structure formed by the physical bond between the cation parts. Among ionic liquids with [$BF_{4}$] as an anion part, the hexyl substituent in the cation parts was more effective to synthesize palladium particles with the smaller size and more uniform shape.