• 한국해양학회지:바다
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• 제10권4호
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• pp.181-195
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• 2005

해상어류가두리양식장의 양식 활동이 해양환경에 미치는 영향을 파악하기 위해 통영주변의 해상어류가두리양식장(Site A)에서 해수유동, 퇴적물, 저서동물 및 트랩 등의 현장조사와 수치모델-DEPOMOD를 이용하여 가두리양식장의 고형물 침강량 예측과 적정 고형물 침강량 산정으로 해상가두리양식장의 환경관리 방안을 제시하였다. 조사대상인 Site A 해상어류가두리양식장의 입식 어종은 common sea bass(Lafeolabrax japonicus), red seabream(Pagrus major), striped breakperch(Oplegnathus fasciatus) 등 4종이고, 입식량은 227,800미 (23.1MT) 였다. 가두리양식장의 입식밀도는 $43.0kg\;m^{-2}(6.1kg\;m^{-3})$ 이고, 사료투여 량은 $30.8g\;kg^{-1}day^{-1}(1.32kg\;m^{-2}day^{-1})$ 이였다. Site A 가두리양식장 중심의 저층 퇴적물의 ORP, AVS, COD, 탄소 및 질소 농도는 각각 -334.6mV, $0.43mg\;g^{-1}dry,\;17.75mg\;g^{-l}dry,\;10.19mg\;g^{-1}dry$ 및 $3.49mg\;g^{-1}dry$ 였다. 저서동물은 Capitella capitata가 $57.8\%$로 우점하였고, Infaunal Trophical Index(ITI)는 가두리 가장자리에서 20m 거리 내까지 20 이하로 나타났다. 트랩조사 결과 Site A의 고형물 침강량은 0m에서 $34,485g\;m^{-2}yr^{-1}$, 42m지점에서 $18,915g\;m^{-2}yr^{-1}$침강하는 것으로 나타났다 모델 예측 결과 Site A의 사료 미섭이율은 $40\%$, 연간 고형물 침강량은 63,401 kg으로 연간 사료 급이량의 $24.4\%$이고, 고형물 침강 면적은 $8,450m^2$으로 가두리 시설 면적의 16배인 것으로 예측되었다. ITI와 저서동물의 풍도를 통한 Site A의 지속 가능한 고형물 침강량은 $10,000g\;m^{-2}yr^{-1}$ 이하 인 것으로 예측되었다. 가두리양식장에서 고형물 침강량의 주 요인은 높은 미섭이율이고, 고형물 침강량을 최소화 하기 위해서는 사료 섭이효율을 높여주어야 한다. 모델에 따르면 미섭이율을 $40\%$에서 $10\%$로 줄이면 고형물 침강량이 1/2 수준으로 감소되는 것으로 예측되었고, 습사료, 생사료의 사용 대신에 배합사료(EP)를 사용할 경우 $57\%$정도 침강량이 감소하는 것으로 나타났다. 또한 가두리양식장의 허가면적에 대한 시설 면적비는 $5\%$미만이 적정한 것으로 판단된다.

• 한국동물위생학회지
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• 제15권2호
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• pp.215-225
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• 1992

To estimate pollution status of livestock wastewater on four piggeries and one abattoir in Taegu area, physicochemical water analysis such as pH, suspended solid(SS), biochemical oxygen demand(BOD) and chemical oxygen demand(COD), and bacteriological examinations such as number of total viable cells and number of coliform with or without antibiotic resistance were carried out. The results obtained were as follows : The pH values of raw sewage ranged from 9.0 to 7.2 that of the effluent treated was lowed to 5.6~7.7. The SS values of raw sewage ranged from 5,275ppm to 120ppm and those of the efflunet decreased to 162~30ppm. The BOD values of raw sewage ranged 6,200ppm to 120ppm and those of the effluent treated decreased to 111 ~80ppm. The COD values of raw sewage ranged from 5,725ppm to 298ppm and those of the effluent decreased to 137~76ppm. The total viable cells of raw sewage ranged from $8.5{\times}11^{11}$/ml to $9.9{\times}10^7$/ml, those of the effluent decreased to $5.6{\times}10^6{\sim}4.2{\times}10^8/ml.$ The total coliforms of raw sewage ranged from $5.5{\times}10^9$/ml to $1.3{\times}10^5$/ml, those of the effluent decreased to $3.6{\times}10^4ml{\sim}9.0{\times}10^6$/ml. The incidence of streptomycin resistant coliforms was the highest(1.8~66.7%), and followed by tetracycline(1.7~64%), kanamycin(9.3~50.l%), ampicillin(0.06~45.5%) and chloramphenicol(14.3~33.5%) to total coliforms of raw sewage. The incidence of antibiotic resistant coliforms of raw sewage in farms ranged from 3.4~66.7% and that of abattoir's was 0.06% to 14.3%. Antibiotic resistant coliform counts of raw sewage ranged from 1.3$\times$10$^{8}$ /ml to 3.9$\times$10$^3$/ml, those of the effluent decreased to $3.0{\times}10^1{\sim}2.3{\times}10^5/ml$.

• 상하수도학회지
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• 제18권4호
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• pp.486-492
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• 2004

CMP (Chemical mechanical polishing) is inevitable process to overcome $0.2{\mu}m$ wire thickness in semiconductor industry. In this study, effect of pressure to separate used CMP slurry into solid and liquid for recycle and reuse by ultrafiltration was investigated. Also, water quality after the ultrafiltration such as turbidity and TDS was evaluated. The material of membrane used in the study was PVDF. The used CMP contained 0.5% of solid content and then concentrated up to 18% by weight. The used CMP can not be concentrated higher than 18% because of viscosity and abrasion of pump. The tested feed pressures were 22.1, 29.4 and 36.8 psi. The results have shown that operating at 36.8 psi has advantages on operation time and total flux. The specific flux showed some variation at 1 to 15 of concentration factor but no difference after 15 of concentration factor. Mass balance of solid at initial stage of the operation showed some unbalance because of deposition of solid on the membrane, which was main reason to reduce flux. Turbidity was very stable at lower than 0.2NTU for 22.1 and 36.8 psi of feed pressure.

• 한국환경과학회지
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• 제17권2호
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• pp.177-183
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• 2008

Characteristic of wastes in a unsanitary landfill at the residential development site in H city, Kyunggi-do was investigated for the disposal of huge amount of wastes. The total amount of wastes was estimated at 117,000 ton and construction solid wastes and municipal solid wastes were detected together. The portion of combustibles was very low and soils, concrete wastes, and pebbles were the major components in landfilled wastes. Because the site was the residential development site, the landfilled wastes should be removed immediately for the construction. Therefore the way that the unsanitary landfill was excavated and the wastes were sorted into three categories such as soils, noncombustibles and combustibles was selected as the best method. Soils and noncombustibles could be recycled and sorted combustibles could be re-landfilled in a smaller area or incinerated.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 춘계학술대회 논문집
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• pp.177-180
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• 2009

직경 대 길이비(L/D)의 값이 큰 고체 추진기관에서는 축방향 연소불안정 현상이 발생할 가능성이 높다. 일반적으로 이러한 현상을 억제하기 위해 추진제에 금속입자를 포함시키거나 그레인 설계시 축방향 압력 진동을 억제할 수 있도록 형상을 고안한다. Slotted-Tube형 그레인을 적용한 고체 추진기관은 연소시 Slot의 영향으로 인해 축방향 압력진동이 억제되나 Slot의 길이가 짧을 경우 연소 중반이후부터 실린더부의 영향으로 축방향 압력진동이 증폭될 수 있다. 본 연구에서는 230mm급 고체 추진기관의 연소 시험 결과 중 압력에 대해 스펙트럼 분석 및 음향모드 해석을 수행하여 축방향 압력 진동 현상을 분석하였다.

• Advances in pediatric surgery
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• 제11권1호
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• pp.40-45
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• 2005

Solid pseudopapillary tumor of pancreas in children is a tumor with low malignant potentiality. and is rarely associated with distant metastasis. A 13-year-old girl was hospitalized because of abdominal pain of one week duration. Abdominal CT revealed not only a $12{\times}6cm$ sized mass at the pancreatic body and tail but also a 1cm sized mass in left lobe of the liver. The patient underwent a near-total pancreatectomy and tumorectomy of the liver. A solid pseudopapillary tumor with liver metastasis was confirmed by pathology. She has undergone 13 courses of chemotherapy and has been well for 13 monthswithout any sign of recurrence.

• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.683-689
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• 2016

Most outdoor solid insulators may suffer from surface degradations due to non-stationary currents that flow on the insulator surface. These currents may be classified as leakage, discharge and tracking currents due to their disturbing potencies respectively. The magnitude of these currents depends on the degree of the contamination of surface. The leakage signals are followed by discharge signals and tracking signals which are capable of forming carbonized tracking paths on the surface between high voltage and earth contacts (surface tracking). Surface tracking is one of the most breakdown mechanisms observed on the solid insulators, especially polymers which may cause severely reduced lifetime. In this study the degradations observed on polyester resin based insulators are investigated according to the IEC 587 Inclined Plane Test Standard. The signals are monitored and recorded during tests until surface tracking initiated. In order to prevent total breakdown of an insulator, early detection of tracking signals is vital. Continuous Wavelet Transform (CWT) is proposed for classification of signals and their energy levels observed on the surface. The application of CWT for processing and classification of the surface signals which are prone to display high frequency oscillations can facilitate real time monitoring of the system for diagnosis.

• 생약학회지
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• 제43권3호
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• pp.250-256
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• 2012

In order to extract the curcuminoid such as curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC) in turmeric (Curcuma longa), solvent extraction methods (dipping and ultrasonic extraction method) and solid-phase extraction (SPE) were used. RP-HPLC (reverse-phase high-performance liquid chromatography) and TLC (thin-layer chromatography) were used for identification and analysis the three curcuminoid. From the experimental results, it is evident that the percentage of curcuminoid extracted from turmeric by ultrasonic extraction method was higher than dipping method. The percentage of curcumin extracted from turmeric by pure methanol was higher than any aqueous methanolic composition. Moreover, the total peak area of three curcuminoid was above 92% in RP-HPLC using solid-phase extraction. These results will form a database for investigating the constituents of natural products and the resources of pharmaceutical, nutrition, and cosmetic products.

• 한국추진공학회지
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• 제24권6호
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• pp.45-52
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• 2020

초소형 스마트탄의 개발을 위해 초소형 추진기관을 설계하고 그레인은 내부 형상의 제작 용이성을 고려하여 열가소성 추진제로 제작하였다. 추진기관의 성능분석을 위해 지상연소시험과 내탄도 해석이 수행되었다. 그리고 사수와 추진기관 간 안전거리 설계에 대한 기초자료를 획득하기 위하여 수치해석을 수행하였으며, 배기가스의 온도분포는 수치해석과 IR 카메라의 측정결과를 비교하여 분석되었다.

• 공학교육연구
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• 제22권3호
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• pp.68-77
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• 2019

This study dealt with a case study on the application of flipped learning to solid mechanics in college of engineering and analyzed the results of Pre-class survey, In-class activities, and Post-class survey to examine the effects of flipped learning. Total sample size of the analysis was 32 students who applied for solid mechanics in mechanical engineering department, consisting of 23 students in sophomore, five in junior and four in senior. The class was operated in three stages: Pre-class, In-class, and Post-class. The response of the students was observed at each stage of the class. According to the results, flipped learning was effective in learning knowledge of major subjects in engineering, and students actively participated in class activities and conducted smooth discussions with team members. Flipped learning has also improved students' class concentration and academic ability. Most of the students have expressed their intention to take classes or actively recommend other students when the classes are held. Effective classes will require systematic discussion guidance because flipped learning is closely related to discussion activities.