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닥나무의 사료가치에 관한 연구 제 2 보 . 닥나무 재배방법 및 엽의 급여가 육성 - 비육돈의 증체에 미치는 영향
정현승,이을희,정장용 ( Hyun Sung Chung,Ell Hee Lee,Jang Young Jung ) 한국축산학회 1980 한국축산학회지 Vol.22 No.5
This experiment was carried out to determine the yield, chemical composition and feeding value of the leaves and rhytidome of Broussonetia kaxirtoici, Sieb. The feeding value of the leaves fed liberally to growing-finishing pigs was determined under the restricted feeding in which the daily allowance of formula feed was 3 % of body weight, compared with 4 % in the controls. Ten pigs of the same litter were alloted in equal numbers into the control and experimental groups and conducted the feeding trial for 2 months. The results obtained are summarized as follows : 1. The annual yield of green leaves of Broussonetia kazinoki, Sieb. grown on the College Experimental Farm was averaged about 2,000㎏/10a. 2. The chemical composition of the leaves was determined on the dry matter basis as follows ; crude protein : 11.4%, crude fat: 4.74%, crude fiber : 32.33%, crude ash : 13.43% and nitrogen free extracts : 37.16%. 3. The chemical composition of the rhytidome was determined on the dry matter basis as follows ; crude protein : 13.43%, crude fat : 5.94%, crude fiber : 33. 19%, crude ash ; 33.60% and nitrogen free extracts : 27.26 %. 4. The body weight gain for 2 months was averaged 33.8㎏ and 36. 2㎏ in the control and experimental pigs, respectively. However, there was no significant (P$lt;0.05) difference in body weight gain between two groups. 5. The feed conversion was improved slightly in the experimental group(3.2) as compared with the control (3.8). 6. The liberal feeding of the green leaves resulted in the decrease of about 60 won in the feed cost for 1 ㎏ body gain of the growing-finishing pigs. 7. The leaves were found palatable to the pigs and the pigs fed the leaves were found to be normal clinically.
돈사상부공간을 이용한 가토사육이 돈의 증체에 미치는 영향 제4보 . 가토분뇨 및 잔사의 자유채식이 사료의 급여수준을 달리했을 때 육성 - 비육돈의 증체에 미치는 영향
정현승,정장용 ( Hyun Sung Chung,Jang Young Jung ) 한국축산학회 1980 한국축산학회지 Vol.22 No.5
This experiment was carried out to determine the effect of liberal feeding of rabbit feces and residual forage on the growth of growing-finishing pigs subject to restricted feeding in which the daily allowance of formula feed was 3 % of body weight, compared with 4 % in the controls. The rabbit feces and residual forage were to be dropped from the hutches above the pig barns. Eight pigs of the same litter gave the similar initial body weight of 40㎏ and were alloted in equal numbers to the control and experimental groups. The results from feeding trial for 2 months are summarized as follows 1. The body weight gain for 2 months was averaged 44.9 ㎏ and 43.0㎏ in the control and experimental pigs, respectively. However, there was no significant (P$gt;0.05) difference in the body gain between two groups. 2. The feed conversion was improved slightly in the experimental group (2.8) as compared with the control (3.4). 3. The palatability of rabbit feces and residual forage to pigs was decreased during the late finishing period. 4. The liberal feeding of rabbit feces and residual resulted in the decrease of about 60 won in the feed cost for 1 ㎏ body weight gain of pigs. 5. The pigs fed rabbit waste and residual forage were found to be normal clinically.
정현승(Jung Hyun Seung),김애화(Kim Ae Hwa) 학습자중심교과교육학회 2019 학습자중심교과교육연구 Vol.19 No.22
본 연구는 중학생을 대상으로 학년과 집단에 따른 기초 연산 유창성 발달 특성과 기초 연산 유창성이 수학 성취도에 미치는 영향을 살펴보았다. 본 연구를 위한 도구개발 및 자료 수집은 2019년 5월 한 달간 진행되었다. 기초 연산 유창성 측정을 위해 덧셈, 뺄셈, 곱셈, 나눗셈별로 두 세트(한 자리 수 연산, 한 자리 수와 두 자리 수 연산)씩 총 8세트의 검사를 제작하여 실시하였고, 수학 성취도 평가는 초등 수준의 연산 능력을 평가하는 초등 수학 성취도 검사와 중등 수준의 연산 능력을 평가하는 유 리수 성취도 검사를 실시하였다. 결과분석을 위하여 다변량 분산분석(MANOVA) 및 중다회귀분석을 실시하였다. 주요 연구 결과는 다음과 같다. 첫째, 학년 및 집단에 따른 기초 연산 유창성의 차이를 살펴보면, 한 자리 수와 두 자리 수의 곱셈 연산 을 제외한 모든 기초 연산 유형에서 학년별 주 효과가 나타났고, 모든 연산 유형에서 집단별 주 효과가 나타났다. 둘째, 수학 성취도에 대한 집단별 기초 연산 유창성의 예측력을 살펴보면, 학습부진의 경우 수학 성취도에 대한 기초 연산 유창성의 설명 력이 일반학생의 수학 성취도에 대한 설명력보다 더 높게 나타났다. 이 연구 결과에 대한 논의를 기술하였다. middle school students and to examine the effect of basic fact fluency on math achievement. For measuring basic fact fluency, eight sets of tests were administered: two sets for each operation of arithmetic(i.e., addition, addition, subtraction, multiplication, and division). For measuring mathematical achievement, two sets of mathematical achievement tests were administered: (a) general math achievement test for elementary school, and (b) mathematics operation test for secondary school. Multivariate ANOVA(MANOVA) and multiple regression analysis were performed for result analysis. Major results are summed up as follows. First, there was a main effect by grade in all subtests of basic fact fluency testexcept multiplication. Also, there was the main effect by group in all subtests of basic fact fluency test. Second, the basic fact fluency accounted for more variance in mathematic achievement for students with learning difficulties than those without learning difficulties. The results are discussed in regard to the results of this study are described.
NaBH4 가수분해 반응에 의한 무인항공기용 PEMFC 수소공급
정현승 ( Hyeon Seong Jung ),조병주 ( Byung Joo Jo ),이정훈 ( Jung Hoon Lee ),이한종 ( Han Jong Lee ),나일채 ( Il Chai Na ),추천호 ( Cheun Ho Chu ),박권필 ( Kwon Pil Park ) 한국화학공학회 2016 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.54 No.1
무인항공기가 장시간 비행하기 위해서는 배터리보다 고분자전해질 연료전지(PEMFC)가 적합하다. 본 연구에서는 PEMFC 에 수소를 공급하는 NaBH4가수분해 반응 시스템에 대해 연구하였다. NaBH4가수분해 반응 시스템의 무게를 감소시키기 위해 수소수율 향상, 응축수 회수, 안정적인 수율 유지 등에 대해 실험하였다. 반응기 압력제어를 함으로써 수소 수율을 3.4%향상시켰다. 수소를 공랭하여 PEMFC 스택에 공급하는 과정에서 발생하는 응축수를 NaBH4 저장조에 회수하였다. 이 과정에서 응축수가 NaBH4분말을 용해시켜 보충됨으로써 14%의 무게 감량효과가 있었다. 2.0 L/min의 속도로 수소를 발생시킬때 Co-P-B촉매 2.0 g을 사용해서 10시간동안 96% 수소수율로 NaBH4가수분해 반응 시스템을 안정적으로 구동하였다. Proton Exchange Membrane Fuel Cells (PEMFC) instead of batteries is appropriate for long time flight of unmanned aero vehicles (UAV). In this work, NaBH4 hydrolysis system supplying hydrogen to PEMFC was studied. In order to decrease weight of NaBH4 hydrolysis system, enhancement of hydrogen yield, recovery of condensing water and maintenance of stable hydrogen yield were studied. The hydrogen yield of 3.4% was increased by controlling of hydrogen pressure in hydrolysis reactor. Condensing water formed during air cooling of hydrogen was recovered into storage tank of NaBH4 solution. In this process the condensing water dissolved NaBH4 powder and then addition of NaBH4 solution decreased system weight of 14%. NaBH4 hydrolysis system was stably operated with hydrogen yield of 96% by 2.0g Co-P-B catalyst for 10 hours at 2.0L/min hydrogen evolution rate.
도시철도 충돌사고 시뮬레이션 및 충돌안전도 개선방안 연구
정현승(Hyun Seung Jung),손승완(Seung Wan Son),권태수(Tae Soo Kwon),김진성(Jin Sung Kim) 대한기계학회 2015 大韓機械學會論文集A Vol.39 No.9
본 연구에서는 서울메트로 2 호선 상왕십리역에서 발생한 전동열차 충돌사고에 대하여 사고재현 시뮬레이션을 수행하고 사고 발생 시 피해를 최소화할 수 있는 개선방안을 제시한다. 사고재현을 위해 상용 충돌해석 소프트웨어인 LS-DYNA 를 사용하여 1 차원 및 3 차원 시뮬레이션을 수행하였다. 1 차원 시뮬레이션을 통해 각 차량 연결기의 하중, 변위, 충격흡수 에너지 및 차량의 가속도를 분석하여 사고 시 충돌안전도를 평가하였으며, 3 차원 시뮬레이션을 통해 차량의 변형 및 타고오름 현상을 분석하였다. 또한 사고 전동차의 충돌안전도 향상을 위한 개선방안들을 제시하고, 그 중 선두차량에 고용량 완충장치를 적용하는 방안에 대하여 1 차원 시뮬레이션을 통해 충돌안전도의 개선 여부를 확인하였다. In this study, we simulate the railway crash accident that occurred at the Sangwangsimni station on the Seoul Metro Line #2, and we propose a solution to minimize the damage. We use LS-DYNA, which is the commercial software employed for collision analysis to perform 1-D and 3-D simulations for the recurrence of accidents. By performing 1-D simulations, we analyze the load, displacement, absorbed energy of the couplers, and acceleration of vehicles, and we evaluate the safety in accidental collisions. By performing 3-D simulations, we analyze the deformation of the car and over-ridding. We propose methods to improve the safety in collisions involving railway vehicles, and we perform collision accident simulations to determine improvements when applying a high-performance energy absorber to the front car.
LS-DYNA를 이용한 철도차량 연결 충돌해석에 관한 연구
정현승(Jung Hyun Seung),권태수(Kwon Tae Soo),구정서(Koo Jeong Seo) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-
In this paper, a simple LS-DYNA shunting impact analysis model for the rolling stocks is proposed. In this model, each vehicle is represented by a 3D solid element and each coupler is represented by a 1D beam element. To describe the dynamic behavior of buffers, a nonlinear material model(MAT_GENERAL_NONLINEAR_1DOF_DISCRETE_BEAM) is used. Friction between the braked wheels and the rails is described by a Coulomb friction model. To verify the proposed LS-DYNA analysis model, a shunting impact simulation is performed and the results are compared with the previous research results.