• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.29-35
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• 2007

The main objective of this paper is to propose the optimal design method of forging process using genetic algorithm. Design optimization of forging process was doing about one stage and multi stage. The objective function is considered the filling of die. The chosen design variables are die geometry in multi stage and initial billet shape in one stage. We performed FE analysis to simulated forging process. The optimized preform and initial billet shape was obtained by genetic algorithm and FE analysis. To show the efficiency of GA method in forging problem are solved and compared with published results.

• Economic and Environmental Geology
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• v.16 no.3
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• pp.135-147
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• 1983

The copper deposits in Goseong district, Gyeongnam area are fissure filled copper veins emplaced on Cretaceous Goseong formation and andesitic rocks. Occurrence of ore veins and mineral paragenesis suggest a division of the hydrothermal mineralization into three stages: stage 1, deposition of arsenopyrite, pyrite, quartz, chlorite and epidote; stageII, deposition of pyrite, chalcopyrite, galena, sphalerite, electrum, pyrargyrite, tetrahedrite, silver sulfosalt minerals, quartz, chlorite, sericite and miner amount of calcite; stage III, formation of barren calcite veins. Filling temperature of fluid inclusions in quartz of stage II, range from 260 to 360 C and salinities from 6.2 to 13.6 weight percent NaCi equivalent.

• Economic and Environmental Geology
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• v.20 no.4
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• pp.223-234
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• 1987

This paper describes the mode of occurrence and mineralogical properties of electrum from the Namseong Gold-Silver deposits, for the purpose of obtaining data on the characteristics of the ore deposits and the behavior of gold and silver during the mineralization. The gangue minerals are quartz, calcite, fluorite. Ore minerals are mainly composed of pyrite, sphalerite, chalcopyrite and galena with minor amount of argentite, electrum, pyrargyrite, native silver and unidenfied mineral(Cu-Fe-Ag-S series). Three stage of mineralization recognized are, from early to later, (I) pyrite-electrum stage (II) sphalerite-chalcopyrite-galena-argentite-electrum stage (III) sulfosalts stage. The filling temperature of fluid inclusions in quartz ranges from $225^{\circ}$ to $335^{\circ}C$. The value of sulfur fugacity estimated by means of electrum-tarnish method ranges from $10^{-11.5}$ to $10^{-14}$ atm. The compositional heterogeneity within a single grain with respect to gold concentration is common in the Namseong electrums Chemical composition of electrum ranges generally between 25~45 atom% Au. Its gold content decreases in late stages of mineralization.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.402-408
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• 2002

Rice cultivar 'Janganbyeo' was cultivated by irrigating the saline waters of high salinity (3.0%) and medium saliniy (1.5%) for 4 days, and low salinity (0.5%) for 30 days at tillering, early meiosis and heading stage. Leaf injury due to salinity was most severe at tillering stage in 1999, but at heading stage in 2000. Heading date was delayed by 1 to 5 days by treatment of saline waters only at tillering stage. Culm length and panicle length were most severely shortened by treatment at early meiosis stage. Yield and yield components except for panicle number were decreased most by high salinity treatment regardless of growth stages. In particular, ripening ratio and grain weight among the yield components were decreased most conspicuously by the saline water treatment regardless of salinity and growth stage. Regarding grain weight grain-filling rate and duration, there is no remarked difference among the concentrations and treatment durations of saline water at tillering stage. However, their reductions were very different among the concentrations and treatment durations of saline water at early meiosis stage, being greatest when treated with high salinity for 4 days and followed by low salinity for 30 days. Also their reductions were very severe only when treated with high salinity for 4 days at heading stage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.478-482
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• 2001

This experiment conducted to know physiological characteristics and stress effect on different growth stage of soybean by night illumination. Soybean variety, Shinpaldalkong 2, Keumjungkong and Muhankong were treated by night illumination with 20~30 Lux (0.05~0.08W m$^{-2}$ , 0.24~0.36 $\mu$㏖ S$^{-1}$ m$^{-2}$ ) for 15 days at six different growth stage, seedling, pre-floral initiation, post-floral initiation, pod filling and seed ripening stage. Night illumination delayed flowering to 2~8 days compared to control. Delay of flowering by night illumination severely effected at the pre-floral initiation stage. Stem length was increased all the night illumination treatments except the pod filling stage. Number of nodes in Shinpaldalkong 2 and Keumjungkong 1 were increased until before post-floral initiation stage but in Muhankong were increased until after post-floral initiation stage by night illumination treatments. Number of pods were decreased all the night illumination treatments except seedling stage compared with control. Yield decreased all the treatments and severe the loss rate degree showed the order of prefloral initiation, post-floral initiation, seedling and flowering stage.

• Economic and Environmental Geology
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• v.20 no.2
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• pp.107-118
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• 1987

The south ore deposits of the Dunjeon gold mine is a fissure-filling vein emplaced in the granitoids, skarnized and hornfelsified rocks of Ordovician Dumudong formation. The vein mineral paragenesis is complicated by repeated fracturing but three distinct depositional stages can be recognized; (1) base metal sulfides stage, (2) base metal sulfides, antimony-bismuthsulfosalts and native metals stage, (3) barren carbonates stage. Gold was mainly deposited in stage II. Fluid inclusion data indicate that fluid temperatures were from $310^{\circ}C$ to $402^{\circ}C$ during stage I and then declined steadily to $148^{\circ}C$ in the closing late stage III. Salinities were in the range of 0.4 to 5.0 equivalent weight percent NaCl and do not reveals any systematic trend through stag I, II and III. Ore mineralogy suggests that temperatures and sulfur fugacities in the earlier stage II were in the range of $340^{\circ}C$ to $360^{\circ}C$, $10^{-8}$ to $10^{-9}$ atm. respectively and then declined steadily to the range of $185^{\circ}C$ to $200^{\circ}C$ and $10^{-17}$ to $10^{-19}$atm. in the later stage II.

• Restorative Dentistry and Endodontics
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• v.9 no.1
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• pp.25-35
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• 1983

The purpose of this study was the observe the toxic effects of root canal sealers in 108 white rats. Experimental animals were divided into control and experimental groups. Theree representative types of materials, such as AH26, Z.O.E. and F.R. were used in this study. Cavities were prepared on the left mandibular area of 108 white rats. Three different sealers were placed in as experiment and bone cavities were left without filling as control. The experimental animals were sacrificed by cervical dislocation at the intervals of 1, 3, 7, 14, 28 and 49 days after filling. Each specimen was fixed with 10% neutral formalin solution, decalcified with 5% nitric acid, embedded in paraffin and sectioned 5-7${\mu}$. in thickness. The paraffin sections stained with Hematoxylin - Eosin were observed through the ordinary light microscope. The results were as follows; 1. Slight toxic effect to surrounding tissue were found in every experimental specimen. 2. AH26 showed the highest inflammatory response, and F.R. showed the lowest inflammatory response which subsided and replaced by fibrosis at 4 weeks after filling. 3. The cavity filled materials, such as implanted root canal sealers, blood clots and necrotic tissue, showed a tendency to be absorbed gradually proportioned to the experimental periods. A small amount of cavity filled materials were observed in the bone cavities after 4 weeks. 4. Fibroblastic proliferation began to produce fibrous capsule around the bone cavity in 2 weeks after filling. Fibrosis was prominent at 4 weeks after filling. 5. Osteoblastic activity of surrounding bone was observed at first in 2 weeks after filling and prominent in 4 weeks after filling. Osteoblastic activity showed an increasing effect as the time prolonged. 6. Surrounding tissue of the bone cavities showed the features of tissue destruction and had very severe inflammatory response at an initial stage. Above-mentioned appeared to be recovered gradually proportioned to the experimental periods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.359-367
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• 1985

This experiment was conducted to study effect of cold water damage on some growth characters related to source and sink at reproductive growth stage in Jinan (sea level 303m). The cold water irrigation duration had irrigated 4, 8 and 12 days at panicle formation stage and reproduction division stage compared to perennial water irrigation. Cold water irrigation shortened culm length and panicle length and degree of panicle exsertion. The shortening effect appeared great at lower internodes when treated at panicle formation stage but at higher internodes when treated at reduction division stage. Cold water irrigation decreased the number of secondary branches and spikelets per panicle, and increased the number of degenerated spikelets being high degeneration when treated at panicle formation stage. Spikelet sterility and impediment of grain filling were affected by duration of cold water irrigation being great when treated at spikelet primodium differentiation stage and reduction division stage in particular. Grain weight was also reduced. Significant relationship existed between spikelets sterility, grain filling and yield. The degeneration of secondary branches and spikelets correlated with leaf area but spikelet sterility and yield with culm length, panicle length and panicle exsertion.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.80-83
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• 2003

Transcribability of pit or land groove structures in replicating an optical disk substrate greatly affects the performance of a high-density optical disk. However, a solidified layer, generated during the polymer filling, deteriorates transcribability because the solidified layer prevents the polymer melt in filling the sub-micro patterns. Therefore, the development of the solidified layer during filling stage of injection molding must be delayed. For this delay, passive heating by insulation layer has been used. In the present study, to examine the development of the solidified layer delayed by passive heating, the flow of polymer melt with passive heating was analyzed. Passive heating markedly delayed the development of the solidified layer, reduced the viscosity of the polymer melt, and increased the fluidity of the polymer melt in the vicinity of the stamper surface with the sub-micro patterns. As a result, we predict that passive heating can improve transcribability of an optical disk substrate. To verify our prediction, we fabricated an optical disk substrate by using passive heating of a mold and measured the transcribability.

• Journal of Korea Foundry Society
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• v.40 no.2
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• pp.34-42
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• 2020

The effects of the initial balancing pressure, filling pressure and maximum build-up pressure on the casting characteristics of the thick-wall thickness casting during the counter-pressure casting process were investigated. Water model experiment and a computer simulation were carried out to evaluate the characteristics during the filling and solidification stages in counter-pressure casting (CPC); as a reference, the low-pressure casting (LPC) process was used. The average dendrite cell size decreased with an increase in the solidification rate and maximum build-up pressure. A turbulent flow occurred during the filling stage of the LPC process, resulting in the formation of inner gas, while a lamellar flow pattern dominated during the CPC process and was more evident with an increase in the initial balancing pressure, improving the mechanical properties of the castings.