• Journal of Energy Engineering
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• v.10 no.3
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• pp.272-277
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• 2001

An experimental study of jet impinging the non-isothermal heating surface with linear temperature gradient is conducted with the presentation of the turbulent flow characteristics and the heat transfer rate, represented by the Nusselt number. The jet Reynolds number ranges from 15,000 to 30,000, the temperature gradient of the plate is 2~4.2$^{\circ}C$/cm and the dimensionless nozzle to plate distance (H/D) is from 2 to 10. The results show that the peak of heat transfer rate occurs at the stagnation point, and the heat transfer rate decreases as the radial distance from the stagnation point increases. A remarkable feature of the heat transfer rate is the existence of the second peak. This is due to the turbulent development of the wall jet. Maximum heat transfer rate occurs when the axial distance from the nozzle to nozzle diameter (H/D) is 6 or 8. The heat transfer rate can be correlated as a power function of Prandtl number, Reynolds number, the dimensionless nozzle to plate distance (H/D) and temperature gradient (dT/dr). It has been found that the heat transfer rate increases with increasing turbulent intensity. The wall jet is influenced by temperature gradient and the effect becomes more important at higher radii.

• Journal of Biosystems Engineering
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• v.9 no.2
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• pp.81-88
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• 1984

현재 축산농가에서 쉽게 구할 수 있는 곡류, 조사료 및 부산물을 활용하여 사료의 자급율을 높이는 것은 농가의 소득증대를 위하여 바람직한 일이다. 이러한 사료의 자급자족 체계를 위하여 소형이며 조작이 간편한 사료분쇄기가 요구된다. 따라서 농가에 많이 보급되어 있는 5~10 마력 (3.7-7.5 kw)의 동력경운기에 의하여 작동될 수 있는 소형 햄머타입의 사료분쇄기 시작기를 설계 제작하였다. 그리고 시작기의 성능을 분석하기 위하여 보리, 옥수수, 볏짚, 건초를 사료로 하여 시료의 공급율과 스크린의 구멍크기를 변화시켜가며 실험을 수행하였다. 이상과 같은 햄머 밀 시작기의 설계 및 성능시험을 통하여 얻어진 결과를 요약하면 다음과 같다. 1. 시작기의 평균분쇄능력은 보리의 경우 평균입자직경이 543 마이크론일 때 $82.7kg/kw{\cdot}h$였으며, 옥수수의 경우에는 평균입자직경이 408 마이크론일 때 $132.7kg/kw{\cdot}h$였다. 2. 최대 공급율로 분쇄할 때 소요동력은 보리의 경우 1.9kw, 옥수수의 경우 5.3kw, 볏짚의 경우 1.5kw, 건초의 경우 1.6kw을 필요로 하였으며, 5-10 마력(3.7-7.5kw)의 동력경운기로 개발된 햄머 밀을 작동함에는 별 문제가 없는 것으로 분석되었다. 3. 시작기로 시료를 분쇄할 때 곡류 분쇄는 물론 조사료 분쇄도 가능한 것으로 분석되었다. 4. 시작기에 의해 시료를 분쇄했을 때 분쇄물의 평균온도 상승폭은 $7.2-10.0^{\circ}C$였다. 이러한 온도는 분쇄물의 영양소 파괴및 저장상의 안정성을 고려할 때 안전한 범위의 온도상승으로 판단되었다. 5. 원료공급율과 스크린 구멍크기가 분쇄량과 분쇄정도에 5% 수준에서 유의성 있는 영향을 미쳤다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.279-279
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• 2022

최근 이미지분석 기술은 하드웨어 및 소프트웨어 기술의 급격한 발전으로 인해 의학, 생물학, 지리학, 재료공학 등에서 수많은 연구 분야에서 광범위하게 활용되고 있으며, 이미지분석은 다량의 토사에 대하여 입경을 포함한 형상학적 특성을 간편하게 정량화 할 수 있기 때문에 매우 효과적인 분석 방법으로 판단된다. 현재 모래의 입도분석 방법으로는 신뢰성 있는 체가름 시험법(KSF2302) 등이 있으나, 번거로운 처리과정과 많은 시간이 소요된다. 또한 입자형상은 입경이 세립 할수록 직접 측정이 어렵기 때문에, 최근에는 이미지 분석을 이용하는 방법이 시도되고 있다. 본 연구에서는 75㎛ 이상의 조립질 하상 토사 이미지를 취득하여, 입자들의 장·축단 길이, 면적, 둘레, 공칭직경 및 종횡비 등의 형상학적 특성인자를 자동으로 측정하는 프로그램 개발을 수행하였다. 프로그램은 이미지 분석에 특화된 라이브러리인 OpenCV(Open Source Computer Vision)를 적용하였다. 이미지 분석 절차는 크게 이미지 취득, 기하보정, 노이즈제거, 객체추출 및 형상인자 측정 단계로 구성되며, 이미지 취득시 패널의 하단에 Back light를 부착해 시료에 의해 발생되는 음영을 제거하였다. 기하보정은 원근변환(perspective transform)을 적용했으며, 노이즈 제거는 모폴로지 연산과 입자간의 중첩으로 인한 뭉침을 제거하기 위해 watershed 알고리즘을 적용하였다. 최종적으로 객체의 외곽선 추출하여 입자들의 다양한 정보(장축, 단축, 둘레, 면적, 공칭직경, 종횡비)를 산출하고, 분포형으로 제시하였다. 본 연구에서 제안하는 이미지분석을 적용한 토사의 형상학적 특성 측정 방법은 시간과 비용의 측면에서 보다 효율적으로 하상 토사에 대한 다양한 정보를 획득 할 수 있을 것으로 기대한다.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.2
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• pp.99-104
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• 2018

A new gerbera cultivar 'Ringgo' was bred by the 'Seohaenongsan' in 2013. 'Ma' with yellow and 'Caravan' with salmon orange, which have semi-double flower, were artificially crossed in 2010. After investigation of the characteristics for four years (from 2010 to 2013), it was selected specially for the use of cut flower. The 'Ringgo' had brilliant orange color (RHS O24A) with dark brown center. The flower was semi-double and 11.1 cm in diameter. And inner ray floret and disc diameter are 6.6 cm and 2.8 cm, respectively. It is a vigorous cultivar having a long and thick peduncle of which length and upper width were 54.7 cm and 4.6 mm, respectively. The vase life of 'Harmony' was 10.1 days, which was 1.2 days longer than the standard cultivar 'Dune'. And its average yield was 55.3 stems per plant, which were 6.6 stems more than the control.

• Advances in pediatric surgery
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• v.5 no.1
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• pp.75-81
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• 1999

A survey on the intestinal atresias was made among 34 members of Korean Association of Pediatric Surgeons. The response rate was 82.4 %. Two hundred and fifteen patients from the January 1, 1994 to December 31, 1996 were analyzed. The lesions were 73 cases of duodenum(DA), 72 cases of jejunum(JA), 71 cases ileum(IA) and 2 cases cecum and sigmoid colon respectively. There were 2 cases of combined anomalies (DA + JA + IA and DA + JA). Male to female ratio was 1:1 in DA, and 1.8:1 in JA. Seventy four cases(34.3 %) were premature babies(DA 35.2 %, JA:48.6 %, IA:19.2 %), and 62 cases(28.7 %) had low birth weight (DA:39.4 %, JA 33.0 %, IA:13.7 %). Antenatal diagnosis was made in 92 cases(43.6 %). However 22 cases (23.9 %) of them were transferred to pediatric surgeon after delivery. Maternal polyhydramnios was observed in 63 cases(28.9 %). Seventy· five cases(34.4 %) were taken only simple abdominal film for diagnostic studies. The associated malformations were observed in 54 aresia and were observed more frequently in DA(35 cases, 47.9 %). Meconium peritonitis due to intrauterine bowel perforation was more frequently associated with IA compared to DA and JA. The overall mortality rate was 30 %. (Abbreuations: $P_{T}$;p-value in total, $P_{DJ,DI,JI}$;p value between two groups among duodenal, jejunal and ileal groups).

• Journal of Sericultural and Entomological Science
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• v.9
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• pp.15-19
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• 1969

Experiments were carried out to make clear the relationships among some morphological characters of four-varieties of mulberry trees. Simple correlation coefficients and particial correlation coefficients were calcultated among the characters, namely branch length, branch diameter, leaf number per branch, leaf area per branch, node number per branch, total branch wt. branch weight except leaves and leaf weight per branch of the mulberry trees. The results obtained are summarized as follows: 1. Variances of the characters and covariances between the each characters are shown in table 1, and simple correlation coefficients among various characters are shown in table 2. It was observed that there were close relationships between yield (leaf weight) and branch length, branch diameter, leaf number per branch, leaf are per branch, node number per branch, total branch weight and branch weight except leaves, respectively. 2. Partial correlation coefficients among some characters are shown in table 3. From this table, it was also observed that leaf yield of mulberry trees and leaf area are more closely related more than leaf yield and the other characters of mulberry trees in four different varieties. From the experimental studies, it was recognized that the four characters, namely branch length, branch diameter, leaf number and leaf area, should be very useful characters in the estimation of mulberry leaf yield as they could be measured. or counted easily before harvest of mulberry leaves, and are affected more in mulberry 1eaf yields than the other characters.

• Journal of Korea Water Resources Association
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• v.37 no.3
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• pp.249-255
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• 2004

To investigate the return flow ratio of irrigation water, lots of observations were made during the irrigation periods in 2003 crop year. This Area is a portion of Dae-Am pumping station basin which is located in Changryung-gun, Gyeongnam province. A water balance analysis was performed for a paddy field in Dae-Am pumping station in the Nakdong river basin, which is constructed for irrigation water supply. Daily rainfall data in the this area were collected and irrigation water flow rate, drainage water flow rate, infiltration and evaportranspiration were measured in field area. Irrigation water flow rate and drainage water flow rate were continuously observed by water level logger(GTDL-L10) during the growing season. The infiltration and evaportranspiration were measured by cylindrical 300mm depletion meter and cylindrical 200mm infiltrometer, respectively. Total irrigation and drainage flows were 654.7mm and 281.2mm in 2003. Total infiltration and evaportranspiration were 36.0mm and 160.0mm respectively. The mean of the daily evaportranspiration rate was 4.3mmm/d. The prompt return flow and retard return flow ratio were 43.0％ and 5.5％, respectively. Total return flow ratio was 48.5％. Therefore, it can be concluded that the amount of irrigation water was much higher than design standard or reference in this study. It means that this was caused by the inadequate water management practice in the area where water was oversupplied on farmers' request rather than following sound water management principles, and design standard should be changed in the future.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.32-32
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• 2012

화석연료의 남용으로 지구 온난화가 심화되어 환경과 생태계변화가 가속화되고 있고, 급속한 산업의 발달과 인류 삶의 질 향상에 따른 에너지 수요가 급증하고 있는 실정에 있으며, 일본 후쿠시마 원전사태로 원자력 에너지의 위험성으로 지구 인류환경은 심각한 국면을 맞이 하고 있어 대체 에너지의 하나로 핵융합 에너지 필요성이 증대되고 있다. 핵융합 에너지 연구 개발은 우리나라에서 KSTAR가 1997년부터 건설하기 시작하여 지난 2007년에 완공되어 지금 운용 중에 있고, 국제적으로 미국, EU, 러시아, 중국, 한국, 일본 인도가 참여하는 ITER 국제 공동프로젝트가 2004년에 건설을 시작하여 프랑스 카다라쉬에 실증 플란트를 건설 중에 있다. 이러한 핵융합 반응을 위해서는 10e-7이상의 높은 진공과 1억$^{\circ}C$ 이상에서 중수소와 삼중수소가 반응하여 발생하는 플라즈마를 제어 할 필요가 있으며, 초고온의 핵융합 플라즈마를 가두고 가동시키기 위해서는 약 12Tesla이상의 고자장 마그넷이 필요하다. 현재 ITER 실증 플란트에 사용되는 고자장 마그넷은 TF (Toroidal Field)코일과 CS (Central Field)코일에 Nb3Sn 초전도선재가 핵심부품으로 사용되고 있으며 ITER프로젝트에서는 약 850톤의 Nb3Sn 초전도선재가 사용될 전망이다. 그 중에서 일본 25%, EU, 러시아와 한국이 각각 20%, 중국7%, 미국8% 할당되어 참여국 대부분은 초전도선재를 전략적으로 공급하고 있다. 초전도 선재의 크롬도금은 1~2 마이크로미터 이하의 균일하고 얇은 도금 두께와 밀착성이 우수한 품질이 요구된다. 일반적으로 크롬도금은 산업현장에서 컨베이어 벨트 방식으로 장식이나, 내식성 및 내마모성의 특성을 필요로 할 때 사용되고 있으나, 선재에 크롬도금을 릴투릴(Reel to Reel) 방식으로 적용되는 경우는 세계적으로 아주 드물다. 핵융합 마그넷의 CICC(Conduct In Cable Conduit)도체를 만들기 위해서는 초전도선재를 이용, 3(Sc 2+OFC 1)$^*3^*5^*5^*6$형태로 연선과 케이블링을 하게 되며, 초전도 선재를 연선하고 케이블링을 할 때 크롬 도금층이 박리될 가능성이 있어 크롬도금 방법과 프로세스를 특별히 고안할 필요가 있다. ITER핵융합로 마그넷의 TF코일은 높이 14m, 폭 9m 최대자장 12Tesla, 최대전류 68kA, CICC도체 직경이 40mm로서 그 초전도 조관/도체 내부에 0.82mm 직경의 Nb3Sn 초전도 선재가 약 1350가닥으로 연선과 케이블링으로 구성되어 있다. ITER 핵융합 마그넷용 초전도 선재의 크롬도금은 마그넷 권선 후 Nb3Sn 초전도물질을 형성하기 위해서 $650^{\circ}C$에서 500시간 열처리를 실시하며 열처리 시 초전도 선재의 소선들 사이에 발생할 수 있는 소착을 방지하고, 초전도 선재에서 발생하는 AC loss를 감소시키며, Quench시 발생되는 열을 쉽게 확산시킴으로써, 초전도 마그넷의 열적 안정성(Thermal Stability) 향상과 필요에 따라서 소선간 통전울 가능하게 한다. 고려제강의 자회사인 케이에이티는 크롬도금 밀착성이 우수하고 도금두께 0.1마이크로 미터 이내 제어가 가능한 얇고 균일한 도금품질을 개발하여 한국형 핵융합 실험로인 KSTAR에 65톤 전량 공급하였고, 크롬 도금된 무산소동 선재 32톤과 초전도 선재 93톤을 전량 ITER 프로젝트에 공급하고 있으며, 2013년도 상반기에는 공급을 마무리할 예정이다.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.183-188
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• 2004

This study was conducted to investigate the effects on the growth and yield by the different seeding methods and cultivating root weight in Atractylodes macrocephata Koidz. Seeding distances were different such as 5${\times}$5 cm, 5${\times}$10 cm, 10${\times}$10 cm, 10${\times}$15 cm by the hand seeder and 15 cm seeding in drill. Emergence date, plant height were not significantly changed with seeding space, but the number of leaf, fresh weight of above-ground part and fresh weight of root were increased in the sparse seeding compared with the dense seeding. The highest fresh root yield was 1,012 kg/10 a at the 5${\times}$5 cm. Roots yield was increased in the sparse seeding compared with the dense seeding, but the highest number of roots above 16 g yield was observed at the 10${\times}$10 cm seeding distance. Emergence date was faster 1∼3 day root weight above 6 g than that root weight 5 g. The plant height, number of stem and fresh weight of above-ground part were more increased as the root weight was heavier. The growth of underground part were more increased as the root weight was heavier, yield was increased about 27％ to 112％ compared with root weight above 6 g than that 134.6 kg/10 a with root 5 g.

• Korean Journal of Medicinal Crop Science
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• v.5 no.4
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• pp.266-275
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• 1997

Anemarrhena asphodeloides BUNGE is one of important medicinal crops, which has been collected or/and cultivated for its rhizomes. The main medicinal ingredient of the A. asphodeloides Bunge rhizomes is a saponin, which is known to have medical values for diaphoresis, sedatives and biuresis. However, studies on cultural methods and breeding works on this plant have not been made in detail. To increase productivity and to improve quality of crops, it is important to collect cultivated and wild lines, to classify them based on morphological and genetic characteristics, and to select superior pure lines at first. Therefore, total 20 A. asphodeloides lines collected were cultivated at the fieldof Chungnam Provincial Administration of Rural Development in 1995 to study the agronomic characteristics and to classify them based on morphological characteristics. Characteristics related with reproductive organ such as the number of spikes per plant and peduncle length showed greater variations than vegetative organrelated characteristics such as leaf length and rhizome length based on the coefficient of variation. Vigorous shoot growth resulted in better development of reproductive organs such as peduncle length and number of spikes per plant. However, the development of spikes was negatively correlated with chlorophyll content. Characteristics of underground parts were more significantly correlated with spike characteristics than aerial part characteristics. A. asphodeloides tested in this study were classified into 2 groups (group A and group B) based on centroid linkage cluster analysis. Group A showed more vigorous shoot growth with more leaves and spikes per plant, longer peduncle length, thicker peduncle diameter and higher shoot dry weight than group B. Group A could be further classified into 2 sub-groups based on leaf size, spike length and peduncle diameter, while group B also could be classified based on number of leaves, number of spikes and shoot dry weight.