• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.1
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• pp.18-26
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• 2016

The semiconductor industry is one of the key industries of Korea, which has continued growing at a steady annual growth rate. Important technology for the semiconductor industry is high integration of devices. This is to increase the memory capacity for unit area, of which key is photolithography. The photolithography refers to a technique for printing the shadow of light lit on the mask surface on to wafer, which is the most important process in a semiconductor manufacturing process. In this study, the width and step-height of wafers patterned through this process were measured to ensure uniformity. The widths and inter-plate heights of the specimens patterned using photolithography were measured using transmissive digital holography. A transmissive digital holographic interferometer was configured, and nine arbitrary points were set on the specimens as measured points. The measurement of each point was compared with the measurements performed using a commercial device called scanning electron microscope (SEM) and Alpha Step. Transmission digital holography requires a short measurement time, which is an advantage compared to other techniques. Furthermore, it uses magnification lenses, allowing the flexibility of changing between high and low magnifications. The test results confirmed that transmissive digital holography is a useful technique for measuring patterns printed using photolithography.

• Korean Journal of Organic Agriculture
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• v.7 no.1
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• pp.35-48
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• 1998

The total amount of dry matter for the green manure crops was great wheat> rye> barley> Italian ryegrass in that order. The green manure crope were verified to have the reducing effect of injury of successive croppingin peper, mainly reducing the occurance of the most important pepper disease, Phytophthora capsisi, and enhancing the pepper quality in the fruit length and diameter. The direct seeding using current commercial pepper variety was proved as not economical one. In the first year of compost application, the growth and yield of red pepper were rather somewhat decreasing compared with those of check plot applied with organic fertilizers. compst application increased the content of organic matter in soil, which suggested compost could be applied for the sustainable purposes. In preference analysis about taking the new technique, the smaller farmer's cultivation area the more they wanted to accept the LISA farming, compared with the conventional one, could be possible to save 12% in the inorganic fertilizer expenses but wasted 412% ant 163% in both organic fertilizer and operator labor expenses, respectively. At the same time, the LISA decreased 15% in production cost but increased 225% and 139% in organic fertilizer quantity and operator labor hours. Since there was a great deal of difference in technological and economic factors from two farming methods, LISA multi-goal decision modeling is further required.

• Food Science of Animal Resources
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• v.27 no.4
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• pp.401-408
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• 2007

This study examined the histochemical and physiological characteristics during Korean native Ogol chickens (KNOC) development. The body weight, Pectoralis major and soleus muscle weights, and muscle samples were taken at hatching as well as at 3, 5, and 15 weeks of age. The fiber characteristics of the Pectoralis major and soleus muscles from the KNOC at hatching to 15 weeks of age were determined, and the deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein concentrations were measured from the left Pectoralis major muscles. A greater increase in body and muscle weights was detected between hatching and 3 weeks of age than during any other period. Moreover, the cross sectional area (CSA) of the fibers, as well as the total concentration of DNA, RNA, and protein also showed a greater increase betweenhatching and 3 weeks of age than during any other period. The KNOC breed is a dual purpose breed, however, the it has lower body and muscle weights than commercial meat type chickens or layer type chickens. Moreover, the KNOC breed has a small muscle fiber CSA of and a low nucleic acid concentration.

• Journal of Bio-Environment Control
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• v.12 no.1
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• pp.7-11
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• 2003

Cellular glass foam (CGF), the reprocessed glass, has a possibility to be used as a medium component in plug culture of horticultural crops due to the its excellent air and water permeability as comparable to perlite. An experiment was conducted to investigate growth of plug seedlings of Lycopersicum esculentum 'Segye' as influenced by irrigation frequency in various medium combinations of CGF (2.0-4.0 mm particle size) and peatmoss. Seeds were sown in 200-cell plug trays, filled with mixtures of CGF and peatmoss either at 33：67 or 25：75 (％. v/v) and were germinated on a fogged propagation bed. The irrigation frequencies used were one, two or three times per every two days. A commercial plug medium (Tosilee medium) was used as the control, and the irrigation frequency in the control was one time per day. Growth of seedlings, and medium pH and EC were measured at 33 days after sowing. The medium composition had little influence on overall growth of seedlings. Irrigation frequency very significant affected number of leaves, leaf area, chlorophyll concentration, fresh and dry weights of shoots and roots, and dry matter. Growth of seedlings was the greatest with the highest irrigation frequency in the 25% CGF＋75% peatmoss mixture.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.527-535
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• 2017

Heat management is one of the most critical issues in Polymer Electrolyte Membrane Fuel Cells (PEMFCs) installed inside the fuel cell power pack of a fuel cell battery hybrid UPS. If the heat generated by the chemical reaction in the fuel cell is not rapidly removed, the durability and performance of the fuel cell may be affected, which may shorten its lifetime. Therefore, the objective of this study is to select and propose a proper cooling method for the fuel cells used in the fuel cell power pack of a UPS. In order to find the most appropriate cooling method, the various design factors affecting the cooling performance were studied. The numerical analysis was performed by a commercial program, i.e., COMSOL Multiphysics. Firstly, the surface temperature of the 1 kW class fuel cell stack with the cooling fans placed at the top was compared with the one with the cooling fans placed at the bottom. Various rotation speeds of the cooling fan, viz. 2,500, 3,000, 3,500, and 4,000 RPM, were tested to determine the proper cooling fan speed. In addition, the influence of the inhaled air flow rate was investigated by changing the porous area of the grille, which is the entrance of the air flowing from the outside to the inside of the power pack. As a result, it was found that for the operating conditions of the 1 kW class PEMFC to be acceptable, the cooling fan was required to have a minimum rotating speed of 3500 RPM to maintain the fuel cell surface temperature within an acceptable range. The results of this study can be effectively applied to the development of thermal management technology for the fuel cells inside the fuel cell power pack of a UPS.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.3
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• pp.101-115
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• 2009

The prompt recovery of housing market in Korea became the national task, for which tools that can analyze the influence that changing situation of housing market and new policy may have on the housing market needs to be developed. Thus, this research intends to develop Multi-Agent Housing Market Model and simulation system in Jinju City as a study area. Analyzing the local housing market of Jinju City, then multi-agent model of housing market that consolidates 3 sub-models, house choice model, hedonic model of house price and location choice model is developed. Moreover in order to develop simulation system the model is programmed in the virtual space of which the size is $150{\times}100$ cell including physical shape of city such as road, urban facilities, land use, etc. With the system, simulations are performed to confirm the impact of urban development on the pattern of residential location. As a result, it is found that the residential location can not be easily induced when only road, commercial and convenient facilities are supplied. However, it is also found that since supplying green results in very many residences, arrangement of infrastructure and environmental factor should be considered at the same time for urban development. As conclusion, it is confirmed that the model and simulation system developed in this research smoothly works to be utilized for the analysis of diverse policy experiment and housing market.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.109-114
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• 2011

The objective of this study was to investigate the effects of environments (farms born, testing groups, age at the tests, date at slaughter, ages at slaughter) on body weights at 6, 12, 18 and 24 months of ages, body type measurements at 18 months of age and carcass characteristics in Hanwoo steer populations that were collected from commercial farms and reared in a progeny testing station. Performances of a total of 1,838 steer calves set for tests from 2004 to 2008 were recorded. Carcass characteristics were the carcass grading results evaluated and data collected slaughter scores at 24 months of age. For growth traits of all age classes and body type traits measured at 18 months of age, farms born, test group and linear covariate of age at test were fit in the models. For carcass traits, date at slaughter and linear covariate of ages at slaughter were fit in the models. Effect of farm at birth was not significant for body weight at 24 months of age. Carcass weight, eye muscle area, yield score and back fat thickness were affected by dates at slaughter but not by the ages at slaughter. Marbling score, however, was affected by these two effects. Farms at birth did not seem to affect body type measures greatly. This study will be utilized for Hanwoo Steers genetic evaluation.

• Journal of agriculture & life science
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• v.45 no.4
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• pp.95-103
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• 2011

Ninety five Hanwoo steers averaging 226kg of body weight were used to investigate the effect of dietary type on feed efficiency, carcass characteristics and economical analysis in Hanwoo feeding over 22 months. Treatments were composed of commercial formula feed (formula feed), TMR and Fermented-TMR (F-TMR). Intakes of dry matter and TDN were greater in the F-TMR than the other treatments during each growing and fattening phase (p<0.05). Although daily body gain of the F-TMR was lowest during the growing phase, but was 48% greater than those of other treatment during the finishing phase (p<0.05). Feed efficiency of the F-TMR was maintained constantly during whole growing and fattening phases. Carcass weight and rib-eye area of the F-TMR were greatest (p<0.05) among treatments. However, meat yield index and the rate of grade A in meat yield were highest in the formula feed having the thinnest back fat. Marbling score was hugely (p<0.05) increased when steers fed F-TMR, and therateofgrade 1+andoverinmeatqualitywas96%intheF-TMR. Although feed cost in the F-TMR was increased by 40% compare to the formula feed, but net income was increased by 29% due to improvement of meat quality and body gain.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.3068-3084
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• 2021

Investigations of large commercial aircraft impact effect on nuclear power plant (NPP) buildings have been drawing extensive attentions, particularly after the 9/11 event, and this paper aims to experimentally assess the damage and vibrations of NPP buildings subjected to aircraft crash. In present Part I, two shots of reduce-scaled model test of aircraft impacting on NPP building were carried out. Firstly, the 1:15 aircraft model (weighs 135 kg) and RC NPP model (weighs about 70 t) are designed and prepared. Then, based on the large rocket sled loading test platform, the aircraft models were accelerated to impact perpendicularly on the two sides of NPP model, i.e., containment and auxiliary buildings, with a velocity of about 170 m/s. The strain-time histories of rebars within the impact area and acceleration-time histories of each floor of NPP model are derived from the pre-arranged twenty-one strain gauges and twenty tri-axial accelerometers, and the whole impact processes were recorded by three high-speed cameras. The local penetration and perforation failure modes occurred respectively in the collision scenarios of containment and auxiliary buildings, and some suggestions for the NPP design are given. The maximum acceleration in the 1:15 scaled tests is 1785.73 g, and thus the corresponding maximum resultant acceleration in a prototype impact might be about 119 g, which poses a potential threat to the nuclear equipment. Furthermore, it was found that the nonlinear decrease of vibrations along the height was well reflected by the variations of both the maximum resultant vibrations and Cumulative Absolute Velocity (CAV). The present experimental work on the damage and dynamic responses of NPP structure under aircraft impact is firstly presented, which could provide a benchmark basis for further safety assessments of prototype NPP structure as well as inner systems and components against aircraft crash.

• Journal of the Economic Geographical Society of Korea
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• v.24 no.2
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• pp.127-142
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• 2021

This study identifies the characteristics of changes in the subway passengers and the number of COVID-19 confirmed cases in Seoul. We classify subway stations by applying the principal components extracted based on the correlation between them, and analyzed the passenger traffics and geographical characteristics of each cluster. We extract the "top decile" and "lowest decile" stations among the subway stations that the number of subway passengers have decreased in 2020 compared to 2019, and then examine the population and land use characteristics of station areas both station groups. As the result of cluster analysis according to principal component scores, we obtain 6 cluster types. Subway stations belong to the top deciles which have shown the larger decrease in the passenger traffics tend to more sensitive to COVID-19 shocks. Stations belonging to the top tenth percentile of reduced traffic have a high distribution of daytime traffic, and the hinterland of the station has relatively high land use related to commercial and cultural, religious, and social activities. Therefore, it is expected that the regional resilience around subway stations will also show differences in degree by type.