• Journal of Embryo Transfer
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• v.32 no.3
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• pp.235-241
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• 2017

To preserve genetic materials, cryopreservation of the semen from live animals is the main technique to establish cryo-banking system which could be used for artificial insemination and embryo transfer. However, the population of Korean black goat (KBG) becomes to dwindle in number and is now faced genetic erosion by crossbreeding with non-native breeds in small KBG farms. In this study, simple freezing method was used to preserve frozen semen from KBG using spermatozoa of cauda epididymis (CE) and electro-stimulated semen (ES). The negative effects of seminal plasma on fresh sperm was confirmed using precipitation test of Triladyl egg yolk diluent and sperm viability after thawing was compared between CE and ES spermatozoa. When seminal plasma of fresh ES semen was washed with semen washing media (SWM), the rates of live sperm shown no significant difference between CE and ES spermatozoa before freezing. However, the survival rate of frozen/thawed CE sperm was higher than ES ($74.6{\pm}10.6%$ vs $53.8{\pm}5.2%$) with significant difference (p < 0.05). The results of longevity test on frozen/thawed sperm from CE showed healthier sperm than ES. Therefore, spermatozoa from CE could be used for cryo-banking system in KBG lines. The more studies are needed to increase survival rate of ES semen.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.165-173
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• 2005

Field observations have been conducted to investigate the physical environment around oyster farms in Gamak Bay. Tidal waves near the two channels at the northeast and south of the bay had almost the same amplitudes and phases. Water temperature responded sensibly to the tides, rising at high water and falling at low water, except for the northwest region. The currents more regularly varied in accordance with a tidal period as long as they are at the faster-flowing region. A considerable flow has been found near the seabed of the northwest of the bay, normally known to be a stagnant area, and also the flow was opposite to the surface flow. Average moving speeds and directions of the flow at each station coincided well with patterns of the residual currents computed by Lee ef al. [2004], except for the northwest region. The discrepancy for the northwest region is not clear but it may have resulted from the facts that the computed flow pattern represents only the case of spring tide and in addition, a northwesterly wind prevailed all the observation time.

• Economic and Environmental Geology
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• v.49 no.3
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• pp.181-191
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• 2016

We estimate the eruption history and magmatic eruptive volumes of each rock units to evaluate the volcanic eruption scale and volcanic hazard of the Ulleung Island. Especially, Maljandeung Tuff represents about 19~5.6 ka B.P. from $^{14}C$ dating, and Albong Trachyandesite, about 0.005 Ma from K-Ar dating in recent age dating data. These ages reveal evidences of volcanic activities within the last 10,000 years, indicating that the Ulleung Island can classify as an active volcano with possibility of volcanic eruption near future. Accumulated DRE-corrected eruptive volume is calculated at $40.80km^3$, within only the island. The calculated volumes of each units are $3.71km^3$ in Sataegam Tuff, and $0.10km^3$ in Maljandeung Tuff but $12.39km^3$ in accounting the distal and medial part extended into southwestern Japan. Volcanic explosivity indices range 1 to 6, estimating from the volumes of each pyroclastic deposits. The colossal explosivity indices are 5 in Sataegam Tuff, and 6 in Maljandeung Tuff in accounting the distal and medial part. Therefore, it is necessary for appropriate researches regarding possibility of volcanic eruption of the island, and establishment system of the evaluation and preparation for volcanic hazard based on the researches is required.

• Korean Journal of Environmental Agriculture
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• v.30 no.4
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• pp.414-418
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• 2011

BACKGROUND: Plastic mulches widely used in raised-bed culture mainly to conserve water, control weeds and raise soil temperature. The most widely used plastic mulch colour is black. Reflective red and far-red light can affect on growth and yield of various vegetable crops. Objectives of this study were to investigate the characteristics of reflective light of black and red plastic mulches, and to evaluate the reflective red and far-red light on the quality characteristics and yield of the Oriental melon (Cucumis. Melo L.) and tomato (Lycopersicon esculentum L.). METHODS AND RESULTS: Oriental melon and tomato were cultivated over the reflective red and black plastic mulches in plastic house. Reflected red and far-red light over the red plastic mulch were 2.6 times higher than those of black plastic mulch. Red to F-Red ratio of black plastic mulch, red plastic mulch and sunlight were 1.14, 0.93 and 1.16 respectively. Intensity of reflected red and far-red light over red plastic mulch were highest at surface height of 30 cm. The higher the height of the surface decrease the intensity of far-red light. Accordingly, Red to F-Red ratio were increased. Reflective red plastic mulch increased the weight of fruit and content of sugar in Oriental melon and tomato. CONCLUSION(s): Yield of Oriental melon over reflective red plastic mulch was higher than that of black plastic mulch. These results suggested that reflected red and far-red light over the red plastic mulch affected allocation of photosynthate in growing Oriental melon.

• Research in Plant Disease
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• v.24 no.3
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• pp.182-192
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• 2018

Since fire blight (Erwinia amylovora) firstly broke out at mid-Korea in 2015, it is necessary to investigate potential spread of the invasive pathogen. To speculate environmental factors of fireblight epidemic based on disease triangle, a fire blight predicting program, MARYBLYT, was run with the measured meteorological data in 2014-2017 and the projecting future data under RCP8.5 scenario for 2020-2100. After calculating blossom period of Singo pear from phenology, MARYBLYT was run for blossom blight during the blossom period. MARYBLYT warned "Infection" blossom blight in 2014-15 at Anseong and Cheonan as well as Pyungtak and Asan. In addition, it warned "Infection" in 2016-17 at Naju. More than 80% of Korean areas were covered "Infection" or "High", therefore Korea was suitable for fire blight recently. Blossom blight for 2020-2100 was predicted to be highly fluctuate depending on the year. For 80 years of the future, 20 years were serious with "Infection" covered more than 50% of areas in Korea, whereas 8 years were not serious covered less than 10%. By comparisons between 50% and 10% of the year, temperature and amount of precipitation were significantly different. The results of this study are informative for policy makers to manage the alien pathogen.

• Journal of Chest Surgery
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• v.39 no.4 s.261
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• pp.298-303
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• 2006

Background: This study was performed to investigate the outcomes of vascular operations that were done in patients with atheroscerosis obliterans (ASO) of lower limb. Material and Method: Forty patients underwent vascular operations from December 1996 to June 2004. The patient's records were analyzed retrospectively. Mean age was $66{\pm}8$ years (range, $47{\sim}81$ years). Gender ratio was 37:3 (male:female). Result: The operations were done on 50 lower limbs of 40 patients. The names of operations were femoropopliteal bypass in 12 patients (30%), femorofemoral bypass in 12 (30%), femorofemoral bypass and femoropopliteal bypass in five (12.5%), aorta-lower limb artery bypass in five (12.5%), axillofemoral bypass in two (5%), iliopopliteal bypass in two (5%), and endarterectomy in two (5%). All bypass surgeries were done with prosthetic conduits. Mean follow up period was $33.2{\pm}23.2$ months (range, $3.8{\sim}90.2$ months). The cumulative patency rates of 1 and 5 years were 75.5 and 58.7% respectively. In six patients, amputation of the lower limb was done. In eight patients, 12 complications occurred. After the first operation, 10 patients underwent reoperations. Conclusion: Our lower limb arterial bypass surgery revealed acceptable patency rate, but not a few patients required reoperations. An epochal treatment modality that can inhibit the progress of ASO and improve long term patency should be established.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.3
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• pp.212-219
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• 2003

This study is to evaluate the characteristics of SCC at the welded region of high strength steel using acoustic emission(AE) method. Specimens were loaded by a slow strain rate method in synthetic seawater and the damage process was monitored simultaneously by AE method. Corrosive environment was controlled using the potentiostat, in which -0.8V and -1.1V were applied to the specimens. In the case of one-pass weldment subjected to -0.8V, much more AE counts were detected compared with the PWHT specimen. It was verified through the cumulative counts that coalescence of micro cracks and cracks for the one pass weldment with -0.8V were mostly detected. In case of the one pass weldment subjected to -1.1V, time to failure became shorter and AE counts were produced considerably as compared with that of the two pass weldment. It was shown that AE counts and range of AE amplitude have close relations with the number and size as well as width of the cracks which were formed during the SCC.

• Journal of fish pathology
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• v.23 no.3
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• pp.293-302
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• 2010

Effects of formalin on removal of Pseudodactylogyrus spp. were examined against naturally infected eel, Anguilla japonica (weight 89.9~96g) at a water temperature of $28^{\circ}$. Prior to experiments for removal of the parasite, the hematological toxicity of formalin bath at 0~500 ppm for 30 min~24 h was assessed by hematocrit values (Ht). Based on the results of Ht, appropriate methods of treatment, concentrations and durations, were examined in the main study. There was no significant (P>0.05) change of Ht in 100 to 200 ppm for 24 h. In contrast, Ht increased significantly (P<0.05) at above 300 ppm. This suggests that physiological damage was caused by formalin bath treating with 300 to 500 ppm. Formalin bath with 100 and 200 ppm for 24 h caused significant decreases (P<0.05) in the infection of the parasite. In conclusion, the 100 ppm formalin for 24 hour-bath was found most recommendable for the effective treatment of Pseudodactylogyrus spp. for the gills of the infected eel because of the median lethal concentration ($LC_{50}$) of formalin to eel; cumulative mortalities were found to be 0 and 13.3%, respectively, following 24 h bathing.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.40-40
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• 2019

시민인식은 하천관리를 포함한 공공정책 수립에 결정적 요소들 중 하나로 강조되고 있다. 따라서 하천관리체계의 변화에 따른 사회적 하천관리에 미치는 영향을 파악하고, 특히 우리나라 물관리 일원화 후 하천의 이용과 관리 및 정책에 대한 시민 인식을 조사하는 것은 향후 하천 정책 수립에 매우 중요하다. 본 연구의 목적은 하천의 이용, 관리(주체), 정책, 기후변화 등에 대한 시민의 관심도와 만족도를 조사하는 것이다. 이번 설문 대상은 전국의 남녀 4,500명(10대~60대)이었으며 패널 참여 방식으로 조사되었다. 설문 문항의 구성은 크게 하천 이용, 하천 관리, 그리고 물관리 일원화와 기후변화 등을 포함한 하천정책 등으로 3대 주제로 세부 문항들이 개발되었다. 설문조사의 주요 결과는 조사대상 시민들의 약 22.9%는 매주 하천을 방문하는 것으로 분석되었으며, 1년간 1번은 하천을 방문(이용)하는 시민들은 85.5%로 나타났다. 자주 방문하는 하천의 규모 혹은 위치는 중(中)하천이 42.2%로 가장 높았고, 대(大)하천은 23.9%, 소(小)하천은 17.5%, 도랑이나 개울은 15.5%로 나타났다. 기타(0.9%)로는 하천 외에도 물을 접할 수 있는 저수지, 인공하천 및 호수공원 등을 이용하는 것으로 나타났다. 하천 방문자 중 최소 2시간을 체류하는 시민 중 약 96.4%는 걸어서 하천을 접근하고, 지하철을 이용하여 하천을 접근하는 방문자는 최소 1시간에서 2시간 이상을 체류하는 것으로 조사되었다. 조사대상 시민들은 하천관리 중에서 접근 편의성(28.4%), 친수시설(자전거 도로, 산책로 등) 관리(24.2%), 수질관리(9.9%)로 만족하는 것으로 나타났다. 반면에 수질(27.4%, WQ(water quality))과 냄새 및 쓰레기(25.5%, OW(odor and waste))가 가장 높게 하천관리의 불만족도를 가지고 있었다. 기후변화 영향에 대한 시민들의 관심도는 WQ (29.6 %), OW (17.7%), 그리고 물부족 (15.1%)의 순서로 조사되었다. 하천의 바람직한 미래상에 대한 관심도는 깨끗한 수질의 하천(36.1%, WQ), 휴식과 산책을 즐길 수 있는 하천(22.9%), 다양한 동 식물의 생태서식공간(14.6%)의 순으로 나타났다. 또한 시민들은 하천관리 기관의 가져야할 역량은 '전문성'이 가장 중요하게 인식하고 있는 것으로 조사되었다. 우리나라 물관리 정책 중 가장 큰 문제로 우선순위 1~3순위 누적 조사 결과, 수질악화(79.9%, WQ), 하천 수생물 훼손(49.6%), 정부부처 간 협력부족(37.6%)으로 인식하는 것으로 나타났다. 끝으로 2018년 추진된 물관리 일원화 후 정부의 물관리 및 하천 정책에 대한 시민들의 관심도는 WQ (46.0%), 물공급 관리 (17.6%), 그리고 생태계 복원 (8.4%)의 순서로 조사되었다. 본 연구의 결론들 중 하나는 현재와 미래 하천에 대한 가장 높은 시민들의 수요는 깨끗한 수질과 생태서식공간이었으며 이는 향후 하천 정책 수립에 있어서 중요한 기초가 될 것으로 전망된다.

• Journal of the Korean Institute of Gas
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• v.25 no.2
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• pp.13-21
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• 2021

Because of the recent expansion of hydrogen vehicle supply, the installation of hydrogen filling station is expected to gradually expand. This study attempts to predict the damage scale and propose a safer design form based on the scenario that assumes the worst case of a hydrogen station. A Flacs solver using computational fluid dynamics (CFD) was used to predict the damage scale, and the accuracy was verified by comparing it with the experimental results of previous researchers. The damage scale prediction was conducted for hydrogen leakage and explosion, and the prediction target was the KR model based on the measured values. And as a comparative review model, a roofless model was selected without a ceiling. As a result of analyzing the two models, it was possible to confirm the accumulation and retention of hydrogen gas up to 60 vol% or more in the KR model, whereas in the case of the Roofless model, the phenomenon of discharge and diffusion to the outside of the charging station by riding the wall after leakage. I was able to check. In conclusion, it was reviewed that the type of hydrogen charging station without ceiling is more advantageous for safety than the hydrogen filling station model.