한국 상장기업의 IT자본과 노동 및 비IT자본의 대체성에 관한 연구

문성배,홍동표 한국은행 2004 經濟分析 Vol.10 No.2

본 연구는 2000-2002년까지의 한국 164개 상장기업에 대한 자료를 이용하여 IT자본과 노동 및 비IT자본간의 대체탄력성(elasticity of substitution)을 측정하였다. 특히 생산요소간 대체성의 척도로서 널리 쓰이고 있는 Allen 대체탄력성(Allen elasticity of substitution)의 문제점을 지적하고 Allen 대체탄력성 뿐만 아니라, 가격탄력성, Morishima 대체탄력성(Morishima elasticity of substitution), 그리고 shadow 대체탄력성(shadow elasticity of substitution)을 측정하였다. 본 연구의 추정결과에 따르면, 첫째, IT자본은 노동과 비IT자본에 대한 대체재(substitute)인 것으로 나타났으며, 우리나라 기업들의 경우 IT자본이 노동을 대체하는 정도보다 IT자본이 비IT자본을 대체하는 정도가 큰 것으로 나타났다. 또한 비제조업보다는 제조업에서, 정보화가 덜 된 기업들보다는 정보화가 많이 된 기업들에서 IT자본의 노동과 비IT자본에 대한 대체성이 강한 것으로 나타났다. This paper examines the substitutability of IT capital for other inputs, such as labor and non-IT capital, using the data on 164 Korean firms from the period of 2000-2002. Estimating various elasticities of substitution between IT capital and other inputs, we find that IT capital is a substitute for labor and non-IT capital. In particular, we find that IT capital is more substitutable for non-IT capital than for labor. We also find that the estimated elasticities of substitution between IT capital and other inputs are higher for manufacturing firms than for non-manufacturing firms, and higher for IT-intensive firms than for less-IT-intensive firms.

알루미늄 7075-T6에 관한 랜덤하중이 작용할때의 피로강도

表東根 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.5 No.-

An investigation was made of cumulative fatigue damage of center holed specimens which subjected to programmed varying load in vending condition. The following conclusions were obtained through the constant stress amplitued experiment and the block loading experiment. 1. In constant loading test, fatigue life was affected by speed of revolution. From experimental data, Nf(100cpm)/Nf(3000cpm) equal to 0.31. 2. In case of Al7075-T6 with varying load, Modified Miner's Rule is not acceptable. 3. In case of Al7075-T6 with varying load, we need modified S-N curve method like Freudenthal-Heller's modified S-N curve method.

P分布 Block荷重에 依한 累積疲勞損傷에 關한 硏究

表東根 弘益大學校 1988 弘大論叢 Vol.20 No.2

An investigation was made of cumulative fatigue damage of center holed specimens which subjected to programmed block fatigue loading with p-distribution in bending conditon. The value of p was changed in the range of 0.25 to 1(0.25, 0.5, 0.75, 1) and the fatigue life was defined on the criterion of fatigue life. The following conclusions were obtained through the constant stress amplitude experiment and the block loading experiment. (1) Miner's hypothesis may be valid for p=0.75, and prediction of fatigue life by Haibach's method agree with experimental data well for the case p=0.5. While the modified Miner method agree with experimental data well for the case p=0.25. (2) In constant loading test, fatigue life was affected by speed of revolution. From experimental data, N(100cpm)/N(3,000cpm) equal to 0.83. (3) For center holed specimen, the final fracture surface located in the central part of the specimen and became large according to increase of the stress amplitude.

鎔接殘留應力이 應力比에 따라 疲勞龜裂傳播에 미치는 影響

表東根,李龍福,金鍾鉉,吳湞淵 弘益大學校 1989 弘大論叢 Vol.21 No.2

To examine the effects of the welding residual stress on Mode I fatigue crack propagation behavior, 3mm thickness SS41 steel plate was welded by an Auto-matic Submerged Arc Welding. Initial residual stress and relaxation residual stresses according to each stress ratio were measured. The fatigue crack propagation behavior from the region of compressive residual stress to region of tensile residual stress was analyzed. The results predicted by the Forman's equation using the superposition approach of the respective stress intensity factors for the initial residual stress and for the applied stress according to each stress ratio were compared with experimental data. The validity of the superposition approach was investigated. The conclusion are summerized as follows: 1. When the component is subjected to a constant amplitude cyclic tensile loading, the welding residual stress is reduced as stress ratio increase. 2. As the fatigue crack is propagation through the compressive residual stress field, it was found that the effects of welding compressive residual stress on fatigue crack growth in weldments, and the stress ratio decreases, become larger and delay the fatigue crack growth rate. 3. For negative values of the effective stress ratio, R? in the welding compressive residual stress field, the prediction of fatigue crack growth rate by the Forman's equation were found to be corresponded to experimental data for stress ratio R?0.3, as the effective stress ratio R? approached zero, when the stress ratio R>0.3 the prediction of the fatigue crack growth rate by Forman's equation were found to be impossible.

疲勞强度에 미치는 鹽水와 노치의 影響에 關한 硏究

表東根 弘益大學校 1987 弘大論叢 Vol.19 No.2

In order to study the differente of fatigue strength in different environments, comparative fatigue tests in the rotating bending were carried out in air and artifical sea water with cyclic rate 750cpm, using smooth bar specimens and Center holed specimens of SM45C and SM5OB steel. The following results were obtained. 1. The relations between the stress amplitude and the number of cycles to failure were found by the least square method as follow. ◁표 삽입▷(원문을 참조하세요) 2. In comparison with the air environment, the fatigue strength decrease about 72% in artificial sea water. The fatigue strength is higher the high cyclic rate than low cyclic rate condition. 4. The fatigue strength decreases with the stress concentration factor K_(t) increases. 5. For the stress concentration factor K-(t) is 2.02, N/N is about 39~54%. 6. For the high stress amplitude level, the final fracture surface located in the central part of specimens and large. But for the low stress amplitude level lo-cated in the circumference of the fracture surface and small. 7. By the macroscopic observation, environment was not effected at the fracture surface.

高强度鋼의 Cyclic-rate 變化에 따른 疲勞强度에 關한 硏究

表東根,李廷澤 弘益大學校 1990 弘大論叢 Vol.22 No.2

This study has been made inverstigation for the difference of fatigue strength under variable cyclic-rate, compared with three types cyclic-rate, 2,700cmp and 100cpm using smooth specimens(K?=1.025) and center holed specimens(K?=2.02) of SCM440 steel were obtained through fatigue tests in the rotating. The following conclusions were obtained 1. The difference of fatigue strength under variable cycle-rate is large more the low stress amplitude level than high stress amplitude level. 2. The fatigue strength decrease with concentration factor increase, but the difference is comparatively decrease more than the concentration factor is high level. 3. According to decrease of the cyclic-rate, the failure time take long time. 4. The form of the fatigue crack propagation showed to the straight line according to increase of the cyclic-rate, and for the stress amplitude level, the final fracture surface located in the central part of specimens and large, and the fracture surface showed to the striation and dimple by the microscopic observation.

턱걸이(Pull-up) 수행 시 숙련자와 비숙련자의 근육사용 차이에 관한 운동학적 연구

임동찬,임지환,박건우,박근표,이광수 순천향대학교 기초과학연구소 2022 순천향자연과학연구 논문집 Vol.28 No.1,2

This study was conducted to find out the difference in the use of latissimus dorsi muscle and forearm muscles between skilled and unskilled people when performing pull-up. The subjects of the study were one skilled in the department of sports science at Soon-chun-hyang University, one unskilled person who had no problems with the musculoskeletal system over the past year, and a total of two people who could do pull-ups more than 20 times. A total of one experiment was conducted, and two tests were conducted. The electromyogram data of the light back and forearm muscles were compared using a wireless electromyogram measurement device (EMG). As a result of the study, first, when performing pull-up, the unskilled person performed the movement with the strength of the forearm muscle rather than the light back muscle compared to the skilled person. Second, when performing pull-up, the skilled person showed similar use of force in both pull-up movements, and for non-skilled people, the activity of the forearm muscle in the second movement was significantly increased.

Cyclosporine과 Ketoconazole의 약물상호작용을 이용한 아토피 피부염 치험 2예

김동원,표형찬,은희철,이유신 大韓臨床藥理學會 1993 臨床藥理學會誌 Vol.1 No.1

대뇌 기저핵 신경세포 일차배양에서 망간에 의해 유도된 Appoptosis : 형태학적인 소견

신동훈,김상표,정용욱,배재훈,송대규,백원기 大韓産業醫學會 2000 대한직업환경의학회지 Vol.12 No.1

목적 : 본 실험은 대뇌기저핵의 신경세포를 배양하여 망간(MnCl₂)을 투여한 후 망간독성에 의한 신경세포의 apoptosis를 형태학적인 소견으로 관찰하였다. 방법 : 배양된 신경세포에 0.01에서 10μM Mnc12를 48시간동안 처리한 후 TUNEL (TdT-mediated dUTP Nick End Labelling)법 및 투과전자현미경학적으로 관찰하였다. 결과 : TUNEL방법을 이용하여 관찰한 결과 TUNEL반응에 갈색으로 양성반응을 나타내는apoptotic 세포의 수가 대조군에 비해 MnCl₂를 투여한 군에서 유의하게 높게 나타났으며(P〈0.05), 투과전자현미경학적 소견상 대조군의 신경세포들은 핵인(nucleolus)이 두드러지게 특징적으로 보이면서 핵막과 세포질내 소기관들이 잘 보존되어 있으며, 세포질내망(ER)과 사립체(mitochondria)를 특히 많이 가지고 있었다. Mnc12를 48시간 동안 처리한 군에서 이질염색질(heterochromatin)이 핵막으로 이동하면서 응집되어 있었으며, 핵내 불규칙한 형태의 염색질이 나타나 분절이 진행되는 소견을 보였고, Apoptosis의 가장 특징적인 초기 소견인 막으로 둘러싸인 반달모양의 핵내염색질의 분절편(fragment-ed chromatin)과 주위의 상대적으로 정상적인 소기관으로 구성된 apoptotic body를 관찰할 수 있었다. 결론 : 신경세포에서 망간에 의해 apoptosis가 유도됨을 형태학적인 방법으로 확인할 수 있었으며 망간에 의한 세포사망양상에 apoptosis가 하나의 기전이 될 수 있을 것이다. Objectives : Manganese is cytotoxic to the central nervous system including basal gan-glia. Its toxic mechanism is related to oxidative stress, mediated by toxic free radicals but is specultives. In the present study , we have investigated to manifest apoptosis in man-ganese-induced cytotoxicity in primary neuronal cell culture of rat basal ganglia. Methods : To detect apoptotic neuronal cells were stained by the terminal deoxynu-cleotide (TdT) -mediated dUTP nick end-labelling (TUNEL) method and apoptotic changesin nuclei of neurons were observed by electron microscopy. Results : We showed that TUNEL immunostain showed brownish signal in the nuclei of apoptotic cells and the proportions of apoptotic cells in Manganese treatment groups were more higher than controls. On transmission electron microscopy, there were chromatine condensation with margination toward nuclear membrane and condensation of cyto-plasm in the treated with luM MnCl²for 48 hours in a basal ganglia neurons. Apoptotic bodies were found and consisted of semilunar-like condensed nuclei with relatively intact cytoplasmic organelles. Conclusions : Apoptosis appears to be one mechanism in the manganese-induced net-ronal cell death. Manganese intoxication is a convenient model for apoptosis study.

16,17세기 청도지역 재지사족의 향촌지배와 그 성격

張東杓 부산대사학회 1998 역사와 세계 Vol.- No.22