• Korean Journal of Soil Science and Fertilizer
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• v.32 no.1
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• pp.68-75
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• 1999

This study was conducted to examine the effects of Arbuscular Mycorrhizae inoculation and phosphorus application on early growth of hot pepper. Gigaspora margarita and Acaulospora spinosa were chosen for this investigation and inoculated into soils of different P levels by varying inoculation time and density. After treatment, some relevant growth responses of hot pepper were measured. Regardless of soil P levels, hot peppers treated with arbuscular mycorrhizal fungi had 5~34% more fresh weight than those untreated, but the effect of inoculation time and density was not different between two species. With decreased P levels, the infection rate and dependency of hot peppers increased. The content of P and K of AMF-inoculated hot peppers increased with increasing P levels, but the shoot to root ratio of those elements decreased. The results of this study showed that inoculation of AMF would be effective in promoting growth of hot pepper seedlings and increase transplant adaptation due in part to the resulted higher root development.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.56-62
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• 2018

The bus bar is an electrical connection widely used for the power supply of skyscrapers and power distribution and industrial equipment electrical panels in industrial plants. There are various materials to be considered in the design of the bus bar, such as material based on the use environment, the sectional area according to the power capacity, the length of the surface circumference, and the tightening method. Even with a bus bar manufactured to a size of sufficient power capacity in the design, if the actual tightening is incorrect, it may lead to fire due to deterioration. For these reasons, a variety of research on the temperature rise of the electrical contact point has continued. However, the temperature rise of the contacts is a consequence of the result, not a direct cause. In this paper, the influence of contact resistance on the fastening force and the overlapping section of the bus bar are investigated by measuring the change in resistance from building the specimen. A total of eight bus bar specimens were manufactured and measured. Resistance was measured by varying the clamping force and the interval between overlapping sections when the specimens were crossed. We propose a safe power connection model by analyzing the contribution of these factors to the actual contact resistance change.

• Journal of Periodontal and Implant Science
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• v.34 no.4
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• pp.733-746
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• 2004

The present study aimed to examine the effects of topical application of alendronate with a collagen membrane on the healing of the calvarial defect in rats, which has a good experimental design for the healing of tissue destruction, To study the effect of alendronate on bone healing, the collagen membrane containing $200{\mu}g$ alendronate was inserted in the defects of the right side and collagen membrane treated with physiologic saline was inserted in the defects of the left side. After 1, 2 and 4 weeks, observation of histologic feature after H&E staining, cell counting after TRAP staining, and hardness measurement(Knoop) were performed. In histologic finding, similar features were shown for both test and control groups each week. In cell counting only the 1 week test groups showed significant reduction of TRAP(+)cells than control groups(p<0.01) and the control groups showed statistically significant difference for 1, 2, 4weeks(p<0.05). In hardness measurement, The 2 week test groups showed significant higher hardness than control groups.(p<0,05) and not 4 weeks. There was significant increase of hardness for both groups as time goes by.(p<0.0l) Therefore local application of alendronate with collagen membrane was somewhat effective in reducing osteoclastic activity and increasing hardness in the early stage of healing. Further investigation concerning the actual effect of alendronate for bony healing will be necessary to apply the clinical cases

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.2
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• pp.33-40
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• 2019

Many companies have tried to develop wind power generators with a larger capacity, smaller size and lighter weight. High temperature superconducting (HTS) generators are more suitable for wind power systems because they can reduce volume and weight compared with conventional generators. However, the HTS generator has problems such as huge vacuum vessel and the difficulty of repairing the HTS field coils. These problems can be overcome through the modularization of the HTS field coil. The HTS module coil require a current leads (CLs) for deliver DC current, which causes a large heat transfer load. Therefore, CLs should be designed optimally for reducing the conduction and Joule heat loads. This paper deals with a structural design and thermal analysis of a module coil for a 750 kW-class HTS generator. The conduction and radiation heat loads of the module coils were analysed using a 3D finite element method program. As a result, the total thermal load was less than the cooling capacity of the cryo-cooler. The design results can be effectively utilized to develop a superconducting generator for wind power generation systems.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.55-70
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• 2009

The long-term effects and the soil environmental changes were examined to ensure the safety of food waste compost in agricultural use. Based on conventional nitrogen application rate of chemical fertilizer, Pig manure compost with $24g\;N\;kg^{-1}$, $8g\;P_2O_5\;kg^{-1}$, and $10.4g\;K_2O\;kg^{-1}$ and food waste compost with $20g\;N\;kg^{-1}$, $20.1g\;P_2O_5\;kg^{-1}$, and $6.5g\;K_2O\;kg^{-1}$ were applied to the paddy soil in $2{\times}2{\times}2m$ lysimeter in which paddy rice (Oryza sativa L. var Chucheong) were grown. The rice grown where food waste compost applied showed better growth responses than control, whereas less yield rate than chemical fertilizer applied. The contents of organic matter, nitrogen, and phosphorus after experiment were increased with compost applied. In addition, it improved soil aeration by the application of food waste compost, while little difference was observed in the quality of surface, infiltrated, and ground water compared to chemical fertilizer applied or control.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.85-100
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• 2006

This paper proposes an optimal design method of linear viscous dampers for the seismic performance of two adjacent structures with different heights. Accordingly, connection method using diagonal bracing between two floors and connection method between two structures are considered, and the effectiveness of the latter method is confirmed through the comparison of the frequency response functions with respect to damping capacity. Moreover, optimal damping to minimize the response of the adjacent structures in the frequency domain is found. The sensitivity of natural frequency and modal damping according to the damper capacity at each floor is obtained for the optimally designed system. From the sensitivity analysis, the modal damping is evaluated to be very sensitive to the damper installed at higher floor. Therefore, sensitivity-based damping distribution method is proposed. Diagonal bracing connection method, uniform distribution method and sensitivity-based distribution method are compared to each other in terms of seismic performance. The comparative results demonstrate that the proposed method is an effective seismic design method for the adjacent structures.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.457-461
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• 2006

비점원 농촌유역으로부터 강우시 영양물질(질소, 인)의 유출특성을 파악하기 위해 2002년부터 2005년까지 5개의 강우사상을 대상으로 $2{\sim}12$시간 간격으로 유량 및 수질을 측정하였다. 강우사상시 TN농도는 유량이 증가함에 따라 상승하여 최대농도를 보인 후, 유량감소에 따라 농도가 감소하는 경우와 초기농도보다 높은 농도로 유지되는 경우의 두 가지 경향을 보였다. TP농도는 유량의 증가에 따라 급격한 상승을 보였고, 최대 값 이후 농도가 낮아져 거의 초기농도에 도달하였다. 또한, 초기농도에 대한 최대농도값의 비는 TP가 TN보다 크게 나타났다. 농촌 소유역에서의 초기유출현상(first-flush)은 40%의 누적유출량을 나타낼 때 TP의 누적유출부하량은 $70{\sim}86%$를 기록하여, 도시유역(60%)과 광역논(50%)보다 크게 나타났는데, 이는 농촌 소유역이 경사가 크고 밭 등에서 강우로 인한 토양침식 등의 영향을 크게 받기 때문으로 사료된다. 4개의 강우사상에 대한 질소의 용존성 성분의 비(TN/TDN비)는 93.6%를 나타내 질소는 대부분 용존성 형태로 유출되는 것으로 나타났고, 인의 용존성 성분의 비(TP/TDP비)는 25.4%를 나타내 인의 대부분 입자성 형태로 유출되는 것으로 나타났다. 따라서, 비점원 농촌유역으로부터 TN부하를 저감시키기 위해서는 용존성 성분을 제공하는 비료의 시용량을 줄여야 하며, TP부하를 저감시키기 위해서는 강우시 입자성 인의 유출을 제어해야 한다. 이를 위해서는 비가 많이 오는 여름철에 나지(裸地)나 밭에 식생이나 멀칭(mulching) 등으로 토양침식을 방지하는 대책이나 하천변에 완충역(riparian buffer zone)을 설치하는 대책이 필요하다. 저수지 관리를 효과적으로 수행하기 위해서는 저수지 내부의 탁도 거동을 정확히 예측할 수 있어야 한다. 따라서 추후 동수역학 및 열역학에 기초한 3차원 수치모형 연구와 성층흐름에 정밀한 밀도류 실험연구 및 이에 대한 적용이 필요할 것으로 판단된다.함으로써 정보의 질적보장과 정보전환의 표준화방안을 제시하는 정보분석시스템이다.이용, 수자원의 지속적 확보기술의 특성에 따른 4개의 평가기준과 26개의 평가속성으로 이루어진 2단계 기술가치평가 모형을 구축하였으며 2개의 개별기술에 대한 시범적용을 실행하였다.하는 것으로 추정되었다.면으로의 월류량을 산정하고 유입된 지표유량에 대해서 배수시스템에서의 흐름해석을 수행하였다. 그리고, 침수해석을 위해서는 2차원 침수해석을 위한 DEM기반 침수해석모형을 개발하였고, 건물의 영향을 고려할 수 있도록 구성하였다. 본 연구결과 지표류 유출 해석의 물리적 특성을 잘 반영하며, 도시지역의 복잡한 배수시스템 해석모형과 지표범람 모형을 통합한 모형 개발로 인해 더욱 정교한 도시지역에서의 홍수 범람 해석을 실시할 수 있을 것으로 판단된다. 본 모형의 개발로 침수상황의 시간별 진행과정을 분석함으로써 도시홍수에 대한 침수위험 지점 파악 및 주민대피지도 구축 등에 활용될 수 있을 것으로 판단된다. 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.1
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• pp.29-37
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• 2008

This study examined principles and techniques of efficient water quality management as well as total coastal pollutant loads and the relevant examples in the advanced countries from the viewpoints of water quality improvement and pollution control in coastal areas. The problems and improvements in an estimation of the current total pollutant loads were also pointed out. In addition, discussion was made on the relationship between total pollutant loads and environmental capacity as well as particulars requiring extensive examination on access to and study on water quality model used as prediction tool for marine environment. Furthermore, this study proposed details of and improvement plans for water quality control to be reflected and absorbed into systems and policies related to coastal water quality. In coastal areas, which are subject to total coastal pollutant loads, it is necessary to calculate pollutant loads reduction and allocation, to propose them in detail in statement in relations to new pollution sources for the corresponding projects or plans in environmental impact assessment and prior environmental review system. Also, in relations to regional plans for coastal management, the local government concerned must focus more on environmental management plan to implement data on pollution sources and pollutant loads flown into sea areas under basic jurisdiction, therefore it is required to actively respond to expansion and introduction of total coastal pollutant loads system in the future. Total coastal pollutant loads system must be expanded and executed by considering characteristics of sea area and changes in the environment of land. For pollution sources in land, the competent authorities in charge of coastal environment will need to initiatively administer supervision, monitoring activities and achieve integration and operation of the related laws by preparing legal bases for management system or adjusting the related laws.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.1
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• pp.12-22
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• 1988

The effects of pH and Aluminum treatment on the seedling growth were examined with 11 cultivar under three levels of pH in nutri-culture.. Growth and yield responses of soil pH and nitrogen fertilization were also studied with five cultivars under 3 levels of soil pH and 3 levels of nitrogen application in the field experiment. The effect of pH on the seedling growth was not significant, but Aluminum treatment significantly decreased the seedling growth in nutri-culture except Dusan ＃12. Chlorophyll contents of leaves, dry weight of plants, culm length, spike numbers per unit area, grain numbers per spike, grain weight, and yield were decreased as the decrease of soil pH, and thus highly significant correlation between soil pH during barley growth and yield was observed in all cultivars examined. The stable cultivars to different soil pH with high yield was not found although the decreases of yield were different with cultivars. The increase of nitrogen fertilization significantly increased the nitrogen and chlorophyll contents of leaves, and dry weight of plants, while showed a little effects on the culm length, spike number per unit area, grain number per spike, grain weight and yield. The yield was significantly correlated with culm length, dry weight of plants, grain numbers per spike and 1000 grain weight at each pH levels.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.571-581
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• 2007

The mechanism of water pollution in Lake Shihwa, one of highly eutrophicated artificial lakes in Korea, has been studied using a numerical 3D physical-biochemical coupled model. In this study, the model was applied to estimate the contribution of land-based pollutant load to water quality of heavily polluted Lake Shihwa. The chemical oxygen demand(COD) was adopted as an index of the lake water quality, and the spatial distribution of an average COD concentration during the summer from 1999 to 2000 was simulated by the model. The simulated COD showed a good agreement with the observed data. According to reproducibility of COD, the high-est levels between 8 and 9 mg/L were shown at the inner site of the lake with inflow of many rivers and ditches, while the lowest was found to be about 5 mg/L at the southwestern site near to dike gate. In the pre-diction of water quality of Lake Shihwa, COD showed still higher levels than 3 mg/L in case of reduction of 95% for land-based pollutant load. This suggests that the curtailment of land-based pollutant load is not only sufficient but the improvement of sediment quality or the increase of seawater exchange should be considered together to improve a water quality in Lake Shihwa.