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      • SM45C의 레이저 표면경화특성

        신호준,유영태,안동규,임기건 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

        Laser surface hardening is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshatfs, lorry brake drums and gears. High power CO₂ lasers and Nd:YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. The heat is conducted rapidly into the bulk of the specimen causing self quenching to occur and the formation of martensitic structure. In this investigation, the microstructure features occurring in Nd:YAG laser hardening SM45C steel are discussed with the use of optical microscopic and scanning electron microscopic analysis. Moreover, This paper describes the optimism of the processing parameters for maximum hardened depth of SM45C steel specimens of 3mm thickness by using CW Nd:YAG laser. Travel speed was varied from 0.6m/min to 1.0m/min. The maximum hardness and case depth fo SM45C steel are 780Hv and 0.4mm by laser hardening.

      • 가열처리에 의한 단감의 이화학적 특성

        손규목,김광호,성태수,김종현,신동주,정지영,배영일 한국식품영양학회 2002 韓國食品營養學會誌 Vol.15 No.2

        단감의 기능성 소재 및 기호성이 우수한 부원료로서의 이용 가능성을 확인하기 위하여 단감새옥를 전처리별 즉, 열처리 온도 (25℃, 75℃ 및 95℃) 에서 NaCl (0, 1, 3%) 농도별로 침적 (1, 5분) 하여 동결건조한 시료구를 대상으로 탄닌, 비타민 C, 색도 및 조직감 등을 분석한 결과는 다음과 같다. 탄닌 성분은 열처리 온도, NaCl 농도 및 침적시간이 증가할수록 탄닌함량이 감소하는 경향을 나타내었으며, 특히, 대조구 (420 mg%) 에 비해 95℃에서 1% 및 3% NaCl 농도에 5분간 침적시 각각 228 및 198 mg%로 감소하였다. 비타민 C 함량은 대조구 (122.4 mg%)에 비해 95℃에서 3% NaCl 농도에 5분간 침적시 75.8 mg% 로 감소하였고, 색도는 열처리 온도, NaCl 농도 및 침적시간이 증가할수록 L(명도) 및 b(황색)값이 뚜렷하게 증가한 반면, a(적색도) 값은 감소하였고, ??E 값은 증가하여 처리조건이 가중될수록 색의 변화가 진행됨을 알 수 있었다. 단감껍질과 전처리한 시료 (95℃, 1% NaCl, 5 분)의 flavonol 함량은 껍질에 myricetin(2.0 ㎍/g), quercetin (34. 5 ㎍/g) 및 kaemferol (1.1 ㎍/g) 성분이 검출되었고, 전처리한 시료는 myricetin (9.5 ㎍/g), quercetin (5.5 ㎍/g)이 검출되었다. 조직감은 대조구에 비해 전처리 (95℃, 1% NaCl, 5분) 한 시료에서 부서짐성, 응집성, 점성 및 씹힘성이 우수하였다. 관능검사는 95℃에서 1% NaCl에 5분 및 3% NaCl 농도에 1부간 침지한 시료가 좋은 평가를 받았다. Sweet persimmon were tested in order to identify their use as secondary material which is excellent in function and taste as food. Samples were soaked for 1 and 5 min with NaCl concentration (0, 1 and 3%) at a certain heating temperature (25, 75 and 9r℃), and then tannin, vitamin C, flavonol, color intensity, sensory test and textural properties were analyzed. The results of the analyses were as follows. Tannins were decreased as heating temperature, NaCl concentration and soaking time were increased, especially, that the control was 420 mg% but decreased 228 and 198 mg% at 95℃ (1 and 3% NaCl concentration) for 5 min, soaked in each. Vitamin C content also decreased more in higher temperature and NaCl concentration than control (122.4 mg%). Color intensity showed higher value in L and b than in heating temperature, NaCl concentration and soaked time longer remarkably, but a value decreased. The peel of sweet persimmons was analyzed myricetin (2.0 ㎍/g), quercetin (34.5 ㎍/g) and kaemperaol (1.1 ㎍/g), but in pre-treatment sample ( 95℃, 1% NaCl concentration and 5 min, soaked ) was showed higher myricetin (9.5 ㎍/g) and quercetin (5.5 ㎍/g). Textural properties were good in pre-treatment sample ( 95℃, 1% NaCl concentration and 5 min, soaked) such as brittleness, cohesiveness, gumminess and chewiness. In sensory analysis, the pre-treatment samples (95℃, 1% NaCl concentration and 5 min, soaked and 95℃, 3% NaCl concentration and 1 min, soaked) were showed higher point than others.

      • 고속주축 모니터링용 광파이버 변위센서의 레이저 다이오드 출력에 따른 성능평가

        박찬규,신우철,홍준희,이동주 한국공작기계학회 2004 한국공작기계학회 춘계학술대회논문집 Vol.2004 No.-

        This paper is to develop an optical fiber displacement sensor for monitoring high speed spindle. Proper magnitude of optical power as well as amplification of output signal are necessary to improve sensitivity of the sensor. In this paper, to meet the need of improvement of the sensor resolution, we choose proper optical power and amplification level through speculating on optical power of a laser diode.

      • 개선된 리커런트 신경망을 이용한 등화기

        박정규,서동신,최한고 國立金烏工科大學校附設生産技術硏究所 1997 産業技術開發硏究 Vol.13 No.-

        An adaptive equalizer in digital communication has been used to reduce intersymbol interference(ISI) and noise via radio and telephone channels. The problem of equalization can be viewed as a classification problem, which seeks to classify an observed channel output into one of the finite symbol points in the data. This paper presents the nonlinear adaptive equalizer using the modified recurrent neural networks(RNNs). The RNN structure used in this paper differs from Jordan's and Elman's RNNs with respect to feedback paths. Comparing with the conventional LMS and the feedforward neural network equalizers, the results of the RNN based equalizer show superier performance in terms of mean square error.

      • 물결합재비 및 단위수량에 따른 고유동콘크리트의 제공학적 특성에 관한 실험적 연구

        김규용,한장현,신동주,신홍철,김무한 忠南大學校 産業技術硏究所 1998 산업기술연구논문집 Vol.13 No.1

        Recently the study on high flowing concrete which has high workability and non-compacting is being proceeded actively in the university and corporative laboratory. There are some cases that has been applied to the field. This high flowing concrete has higher fluidity and segregation resistance than Plain or flowing concrete. And it is being focused as a remarkable know-how which can make high-quality concrete and reduction effect of labor force. This properties of high flowing concrete are influenced by the relationship of several factors; binder content water binder ratio and unit water content. It is the aim of this study to propose reference data at mix design of high flowing concrete, after comparing and analyzing the fluidity and strength properties of high flowing concrete according to water binder content ratio and unlit water content.

      • 고속주축 모니터링용 광파이버 변위센서의 파이버 특성에 따른 센서 성능 연구

        박찬규,신우철,배완성,홍준희,이동주 한국공작기계학회 2003 한국공작기계학회 추계학술대회논문집 Vol.2003 No.-

        To make high speed spindle system work properly, sensors with outstanding resolution and dynamic characteristics are essential. An optical fiber displacement sensor is based on simple principles. Electrical signal responds to the optical flux change due to the displacement change between a target and a sensor probe. In this paper, the performance of optical fiber displacement sensor has been investigated according to properties of optical fiber. Firstly, optical loss has been measured before and after polishing optical fiber endface. Secondly, allowance of optical fiber bending has been tested. thirdly sensitivity and linear range of the sensor has been found out according to the shape of cross section of optical fiber.

      • 당뇨병성 합병증을 가진 환자에서 혈중 Erythropoietin 농도

        김동규,유기동,허광식,김상용,윤성호,조영신,권용은,김태원,김건영,정종훈,배학연 朝鮮大學校 附設 醫學硏究所 1998 The Medical Journal of Chosun University Vol.23 No.1

        연구 배경 : 고혈당성에 의한 산화환원반응 이상(가저산소증)이 조절 되지않는 당뇨병의 특징으로 혈관과 신경 기능에 대한 진성 저산소증의 효과와 유사하며, 당뇨 합병증의 병태생리에 중요한 역할을 한다. 고혈당이 있는 인슐린 비의존형 당뇨병 환자에서 인슐린 수준이 정상이듯이, 빈혈이 있는 당뇨병 환자에서 EPO의 농도는 실제 혈색소 농도의 감소비율과 차이가 있을 것이라 추측된다. Friedman 등은 당뇨병성 합병증 원인 인자로 가저산소증(pseudohypoxia) 또는 저산소증(hypoxia)을 제기하였고 이런 인자들이 EPO의 상대적 또는 절대적 결핍에 의한 것임을 보고하였다. 방법 : EPO-Trac^(TM 125)I RIA kit을 이용하여 방사면역측정법으로 EPO 수준을 검사하였다. 전혈 3㎖을 5-10㎖ 시험관에 정맥 채혈하였으며, 용혈과 장기간의 보존을 위하여 원심분리를 즉시 시행하여 혈청을 영하 200C에서 냉동 보관 후 일괄적으로 검사 결과를 얻었다. 결과 : 1996년 9월부터 1997년 2월까지 조선대학교 부속병원 내과에 입원한 2형 당뇨병 환자 63례를 대상으로 하여 다음과 같은 결과를 얻었다. 1) 당뇨병성 합병증이 없는 군과 있는 군간의 혈색소, 혈중 EPO농도의 차이는 유의한 차이가 있었으며 혈색소의 감소율보다 혈중 EPO의 감소율이 더 높았다. 2) 당뇨병성 망막증의 유무에 따른 혈색소 농도의 차이는 유의한 차이가 없었으나 혈중 EPO농도는 유의한 차이가 있었다. 증식성군에서만 혈중 EPO의 감소비율이 혈색소에 비해 높았다. 3) 당뇨병성 신증의 유무에 따른 혈색소, 혈중 EPO농도는 유의한 차이가 있었고 혈색소 감소율에 비해 EPO농도의 감소율이 높았다. 신증의 중증도에 따른 혈색소, EPO의 차이는 미세알부민뇨군을 제외하고는 유의한 차이를 보였고 혈색소 감소율에 비해 EPO의 감소율이 더높았다. 4) 당뇨병성 신경병증의 유무에 따른 혈색소 농도의 차이는 유의한 차이가 없었으며 EPO농도는 유의한 차이를 보였다. 혈색소와 EPO의 감소비율은 비슷하였다. 신경병증의 중등도에 따른 혈색소와 EPO농도의 변화는 유의한 차이가 없었으나 stage 3에서는 혈색소감소율보다 EPO감소율이 더높았다. 결론 : 당뇨병성 합병증을 가진 환자에서 빈혈의 정도는 대부분 혈청 EPO치의 절대적 감소에 의함을 간접적으로 밝혀낼 수 있었으며 차후 더 많은 대상으로 비교 분석이 필요하리라 사료된다. Background: Hyperglycemic-induced redox(pseudohypoxia) imbalance is a characteristic feature of poorly controlled diabetes that mimics the effects of true hypoxia on vascular and neural functions and plays an important role on the pathogenesis of diabetic complications. As is true for apparently "normal" insulin levels typically found in NIDDM even in the presence of hyperglycemia, a "normal" erythropoietin level in an anemic diabetic subject may be disproportionally low for the actual red cell mass. Therefore, Friedman et al suggested that pseudohypoxia or hypoxia as an etiological factor of diabetic complications are due to absolute or relative erythropoietin deficiency Method: EPO-TracTM 125I RIA kit was used for the quantitative determination of erythropoietin(EPO) in serum by radioimmunoassay. An adequate sample of blood (3ml whole blood) was collected aseptically by venipuncture in a 5~10ml glass tube to yield a minimum of 400 L of serum per assay. The serum was promptly removed from the clot by centrifugation in order to avoid hemolysis. Then to increase its storage time it was frozen at -200C in a nonself defrosting freezer. Finally, tests were undertaken simultaneously Results We studied 63 cases with diabetes mellitus, who were admitted to Chosun University Hospital from September, 1996 to February, 1997 at the Department of Internal Medicine. We defined the control group, as diabetic patients who did not have anemia(<13mg/dl), diabetic complications(retinopathy, nephropathy, neuropathy) and the remainders were defined as the experimental group(we excluded anemic patients, who had secondary causes of anemia and diabetic patients with end stage renal disease)Data were as follow 1) The relationship of Hb and the 24hr urine protein between diabetic patients with and without complications significantly differed(p=0.02, < 0.001 respectively), but the Hb level was poorly related between diabetic patients with and without retinopathy(except in preproliferative, proliferative subgroups) and neuropathy. 2) Subgroups of patients with diabetic complications had higher 24hr urine protein than patients without diabetic complications, except stage I diabetic neuropathy 3) The EPO level was significantly different between diabetic patients with and without complications. 4) The correlation between EPO and Hb was significantly different, especially in diabetic patients with retinopathy and nephropathy according to severity of diabetic complications, compared with patients who did not have diabetic complications such as retinopathy and nephropathy. Conclusion: We know that anemia induced by diabetic complications is due to relative EPO deficiency than absolute EPO deficiency, and further evaluation and studies are needed on many cases in the future

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