용접판재의 피로강도에 미치는 잔류응력 평가

차용훈,김덕중,이연신,채경수,성백섭,박회식 조선대학교 동력자원연구소 1997 動力資源硏究所誌 Vol.19 No.1

The objective of this thesis is to investigate the influence of the initial residual stress on the fatigue crack growth after the distribution of the initial residual stress is measured when the crack is growing from the compressive residual stress to the tensile residual stress field. In the case of as welded material, respective of load ratio, the span of the fatigue is the shortest in base metal, while in weld metal and HAZ, the crack growth was retarded due to the effect of the compressive residual stress at the crack tip as well as the span of the crack is longer than base metal. In region II that is in stable growth state of the fatigue crack, da/dN=C(ΔK)^m of power law was satisfied. Also, it was considered that the value of m is not affected by residual stress. Superimposing welding residual stress intensity factor K_res on ΔK, the value of ΔK_eff calculated was lower than ΔK in the same value of da/dN, while the ΔK_eff is almost the same at the high ΔK.

ESPI法을 利用한 點 熔接部의 面內變位 測定에 關한 硏究

차용훈,김덕중,이연신,채경수,성백섭 조선대학교 생산기술연구소 1997 生産技術硏究 Vol.19 No.1

Electronic Speckle Pattern Interferometry(ESPI) using the Model 95 Ar laser, a video system and an Image processor was applied to the in-plane displacement measurements. Unlike traditional strain gauges or Moire method, ESPI method requires no special surface preparation or attachments and can be measured in-plane displacement with no contact and real time. In this experiment specimen was loaded in parallel with a loadcell. The specimen was the cold rolled steel sheet of 2mm thickness. which was attached strain gauges. The study provides an example of how ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI compare with the data which was measured by strain gauge method in tensile testing.

Nutritional Intake and Biochemical Status in Blood and Urine of Elderly Women : Comparison Among Subgroups Divided by Residence Type

Cha,Youn-Soo,Sohn,Hee-Sook,Joo,Eun-Jung 韓國營養學會 1997 Journal of Nutrition and Health Vol.30 No.9

Dietary Docosahexaenoic Acid Decreases Plasma Triglycerides with Mixed Effects on Indices of β-oxidation

Cha,Youn-Soo,Li,Bangyan,Sachan,Dileep S,Whelan,Jay 韓國營養學會 1997 Journal of Nutrition and Health Vol.30 No.9

신경회로망을 이용한 용접잔류응력 예측에 관한 연구

차용훈,김일수,김하식,이연신,김덕중,성백섭,서준열 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.6

In order to achieve effective prediction of residual stresses, the series experiment were carried out and the residual stress-es were measured using the backpropagation algorithm from the neural network and the sectional method. Using the experimental results, the optiomal control algorithms using a neural network should be developed in order to reduce the effect of the external disturbances on residual stresses during GMA welding processes. The results obtained from the comparison between the measured and calculated results, showed that the neural network based on backpropagation algorithm can be used in order to control weld quality. This system can not only help to under-stand the interaction between the process parameters and residual stress, but also, improve the quantity control for welded structures. The development of the system is goal in this study.

강우렁이 (Sinotia quadrata)의 營養學的 硏究 : 아미노산, 지방산, 무기물의 조성에 관하여 On the Composition of Amino Acids, Fatty Acids & Minerals

車連水,李泰圭,梁熙天 又石大學校 1984 論文集 Vol.6 No.-

This experiment was attempted to studies on nutrition value of pond snail. The results are summarized as follows. 1. The proximate composition of pond snail was shown to be crude protein 60,84%, Crude vat 7.89%, CRUDE ASH 14,26% and total sugar 17.89%, respectively. 2. Glu. Asp. Leu. and Phe. were dominant amino acid in pond snail, having 16.77%, 8.6%, 7.99% and 7.19% of total free amino and content respectively. The content of essential amino acid were Ileu. 217.9mg, Leu467.3 mg, Lys. 393.4 mg, Phe. 421.1 mg, Thr. 269.0 mg and Val. 251.1 mg, respectively. 3. The predominant fatty acids were Stearic 30.97%, Palmitic 28.49%, Linolenic 15% and Linaleic 8.12%, Respectively and the P/S Ratio was 0.54. 4. The content of minerals in pond snail were K 1050 mg, Na 106 mg, Ca 1202 mg, Mg 43.3 mg, Cu 10.5 mg, Fe 8 mg and Zn 0.9 mg, respectively.

레이저 계측에 의한 맞대기 용접부의 스트레인 측정

성백섭,차용훈,박창언,김일수,김덕중,이연신,손준식 한국공작기계학회 2001 한국공작기계학회 춘계학술대회논문집 Vol.2001 No.-

Currently knowledge of strain in welds has mainly been obtained from strain gaging method; that is directly attaching most of the material to the gage. The very few non-contact method are still in the early stage. One of the non-contact methods is by the use of the laser that has high-level of the accuracy for the measurement, and this laser also has excellent characteristics on which many studies for its applications are focused throughout the many fields. The dissertation is on the measurement of the strain caused by the characteristics and the temperature changes of the TIG welded zone which is used with 3D ESPI system that is functionally modified through the laser ESPI system. This system employed the aluminum sheet-metal which are mainly used for the steel plate such as for the electronics, chemistry, food instrument and electronic appliances.

운동이 일부 남녀 대학생들의 혈청과 뇨중 칼슘, 마그네슘 및 아연함량에 미치는 영향

임상선,김형락,차연수,안창범,정복미 여수대학교 1997 論文集 Vol.11 No.2

This study investigated the effect of regular exercise on mineral status in college students. Mineral status for calcium, magnesium, and zinc was evaluated prior to beginning the study and again after 35 days of exercise training for 30 minutes per day. The results obtained were summarized as follows: 1) Serum concentrations of calcium and magnesium were decreased in female subjects but were not affected in males. 2) Urinary excretion of calcium and magnesium was significantly increased in male subjects but unchanged in females. 3) Serum and urinary zinc concentrations were not affected in either male or female subjects. These results suggest that regular exercise may have different effect on calcium and magnesium in humans, depending on gender.

중년 여성의 평상 식이 지방산이 체지방 함량 및 혈중 지질 함량에 미치는 영향

주은정,손희숙,차연수 동아시아식생활학회 1996 동아시아식생활학회지 Vol.6 No.1

The present study undertaken to investigate the interrelationship among their regular dietary fatty acid intake, body fat content(BFC), and plasma lipid fractions(PLF) of middle-aged Korean women. Forty-nine women(age 30 to 49) participated in this study in which the aim was to determine their total nutrient intake per day, BFC and PLF, and to analyse the intercorrelations of these. Strong correlation was seen among their body mass index, mid-upper-arm-circumference, and BFC which were positively correlated with plasma total lipids(TL) and triglycerides(TG). Dietary myristic acid and lauric acid were positively correlated with both total cholesterol(TC) and LDL-cholesterol(LDL-C) in plasma. Palmitic acid, stearic acid, oleic acid, and total monounsaturated fatty acid(MUFA) were negatively correlated with HDL-cholesterol(HDL-C). Although dietary total saturated fatty acid(SFA) was not correlated with TC and LDL-C, it was positively correlated with TL and TG in plasma. However, dieary n-3 polyunsaturated fatty acid(PUFA) in regular Korean diet was not correlated with any of lipid fractions in plasma which might he due to the high ratio of n-6/n-3 in their diet. From the above results, it was concluded that plasma lipid fractions were modulated by their dietary nutrients, especially the types of the fatty acids. Dietary SFA and MUFA intake not PUFA are strongly correlated with LDL-C and HDL-C in the Korean diet. This may relate to the frequency of coronary heart disease in the age group.

당뇨병 환자에서 혈장 Thrombin-Antithrombin Ⅲ 및 Plasmin-α_2-Plasmin Inhibitor 복합체의 임상적 의의

김경욱,김은숙,정상수,윤수지,박우일,이준희,남수연,안철우,문병수,김경래,차봉수,송영득,임승길,이현철,허갑범 대한당뇨병학회 2002 Diabetes and Metabolism Journal Vol.25 No.5

연구배경:당뇨병 환자에서 혈액응고 및 섬유소용해 체계의 이상경향이 있어 그 결과로 여러 혈관합병증의 발생위험이 높다는 사실은 널리 알려져 있다. 그 기전은 아직 확실히 밝혀지지 않았으나, 고혈당으로 인한 혈장 단백질들의 비효소성 당화작용이나 산화성 스트레스로 인한 유리 라티칼 작용으로 응고항진이나 섬유소용해 활성의 저하를 유발하는 것으로 생각되고 있다. 최근 응고 및 용해인자와 그 억제자의 복합체들의 증가가 이 상태를 비교적 예민하게 반영한다고 알려져 있다. 방법:본 연구에서는 당뇨병 환자 101명과 정상 대조군 20명에서 혈장내 thrombin­antithrombin complex(TAT)와 plasmin­α₂­plasmin inhibitor complex(PIC)를 측정하여 비교하고, 당뇨병 환자에서 미세혈관 합병증과 대혈관합병증의 유무에 따른 차이와, 이미 혈관 질환의 위험인자로 알려져 있는 인자들간의 상관성을 알아보고자 하였다. 결과:1. 환자의 분포를 살펴보면 혈관합병증이 있는 군은 85명, 혈관합병증이 없는 군은 16명이었고, 평균연령은 각각 57.9±14.1세, 49.9±16.6세로 혈관 합병증이 있는 군에서 더 나이가 많았고, 체질량지수는 23.2±3.4㎏/㎡, 24.1±3.4㎏/㎡로 두 군간 유의한 차이는 없었다. 또 두 군간의 혈압 및 HbA1c, 공복혈당 및 인슐린과 C­peptide, 총 콜레스테롤, 중성지방, HDL­콜레스테롤, Lp⒜는 유의한 차이가 없었고, 미세혈관합병증이 있는 군에서 당뇨병의 유병기간이 길었다. 2. TAT 및 PIC의 농도는 정상 대조군에서는 2.8±1.2 ng/mL, 240.4±69.7 ng/mL이었고, 당뇨병 환자군에서는 9.5±22.6 ng/mL, 472.2±258.7 ng/mL이었다. TAT와 PIC 모두 당뇨병 환자군에서 정상 대조군에 비해 유의하게 증가되어 있었고(p<0.001), TAT/PIC ratio는 두 군간 차이가 없었다. 3. 당뇨병 환자의 혈관합병증에 따른 TAT 및 PIC, fibrinogen 농도는 합병증이 없는 군은 각각 4.1±2.4ng/mL, 362.2±272.0ng/mL, 322.7±102.4mg/mL으로 PIC와 fibrinogen의 증가를 보였으나, 연령을 보정한 후에는 통계학적 유의성은 없었다. 또 대혈관 합병증군에서는 각각 6.0±4.9 ng/mL, 507.4±321.6 ng/mL, 427.1±194.7 mg/dL이었으며 미세·대혈관 합병증군에서는 10.4±6.4 ng/mL, 484.8±269.7 ng/mL, 388.4±132.4 mg/dL으로 TAT의 증가를 보였으나 역시 연령을 보정한 후에는 통계학적 유의성은 없었다. 4. 미세혈관합병증군에서 HbA1c(>8%)가 높은 군의 PIC 농도가 유의하게 높았고(p=0.049), 대혈관합병증군에서 HbA1c(>8%)가 높은 군의 총 콜레스테롤 농도가 유의하게 높았다(p=0.042). 5. 총 당뇨병 환자군에서 PIC는 fibrinogen과 HbA1c와 양의 상관관계를, BMI와 음의 상관관계를 보였으며(r=0.47, 0.31,-0.25), 혈관 합병증이 없는 당뇨병 환자군에서만 TAT는 HbA1c와 양의 상관관계를 보였다(r=0.67). 결론:이상의 결과에서 혈장 TAT 및 PIC 농도는 당뇨병 환자에서 정상 대조군에 비해 의미있게 증가되어 있었고, 당뇨병 환자군에서는 연령의 증가와 유병기간이 혈액응고항진 및 용해의 장애에 큰 역할을 함을 알 수 있었으며, 총 당뇨병 환자군에 PIC와 HbA1c와 양의 상관관계를, BMI와 음의 상관관계를 보였으며 혈관 합병증이 없는 당뇨병 환자군에서만 TAT는 HbA1c와 양의 상관관계를 보였다. 따라서 당뇨병 환자에서 혈액응고 및 용해의 장애가 동반되어 있다고 볼 수 있으며, 혈장 TAT 및 PIC는 혈관합병증으로의 진행을 예측하는 지표로서 유용하리라 생각된다. 또 혈당조절정도와 상관성이 있으므로 혈당조절후에 추적검사를 시행하여 합병증의 예방이 가능한지 추후 연구가 필요하리라 생각된다. Background : Abnormality of coagulation and fibrinolystic system is known as a predisposing factor of vascular complication in diabetes. Although the pathogenesis is not well known, non-enzymatic glycation reaction and the increase in production of free radicals due to an increased oxidative stress may be linked to the hypercoagulibility and hypofibrinolytic activity. As indices of abnormality in coagulation and firinolysis in peripheral blood, plasma thrombin-antithrombin Ⅲ complex (TAT) and plasmin-α_2-plasmin inhibitor complex (PIC) were measured. The purpose of this study was to clarify whether hypercoagulability exists in diabetic patients with or without vascular complication. Methods : In our study, we measured plasma thrombin-antithrombin Ⅲ compelx (TAT) and plasmin-α_2-plasmin inhibit or complex (PIC) in 101 diabetic subjects and 20 controls. Comparing TAT and PIC levels in diabetic microvascular complication group, diabetic macrovascular complication group and controls, we examined correlation between risk factors associated with diabetic vascular complication. Results : 1. The group with diabetic vascular complication was older than group without complication. There was no significant difference in BMI, blood pressure, HbA_ic, blood sugar level, insulin, C-peptide, serum creatinine, total cholesterol, triglyceride, HDL-cholesterol, Lp (a) between two groups. The group with diabetic microvascular complication had longer duration of diabetes. 2. Concentration of TAT and PIC were 2.8±1.2 ng/ mL, 240.4±69.7 ng/ mL in controls and 9.5±22.6 ng/ mL, 472.2±258.7 ng/ mL in diabetic patients, respectively. TAT and PIC were significantly higher in diabetic patients than in control (p<0.001). But TAT/PIC ratio was no significant difference between two groups. 3. In diabetic patients, concentration of TAT and PIC and fibrinogen were respectively 4.1±2.4 ng/ mL, 362.2±272.0 ng/ mL, 322.7±102.4 mg/ dL in group without vascular complication and 5.3±4.1 ng/ mL, 529.5±258.7 ng/ mL, 374.9±106.2 mg/ dL in group with microvascular complication, which group had increase in PIC and Fibrinogen but no significance after correction of age. Concentration of TAT and PIC and Fibrinogen were 60.±4.9 ng/ mL, 507.4±321.6 ng/ mL, 427.1±194.7 mg/ dL in macrovascular complication, and 10.4±6.7 mg/ mL, 484.8±269.7 ng/ mL, 388.4±132.4 mg/ dL in combined vascular complication which group showed increase of TAT but also had no significant increase after correction of age. 4. In diabetic microvascular complication patients, group of high HbA_1c (>8%) (p=0.049) had significant high PIC concentration. In diabetic macrovascular complication patients, group of high HbA_1c (>8%) (p=0.042) had significant high total cholesterol concentration. 5. In all diabetic patients, PIC was positively correlated with fibrinogen and HbA_1c and negatively correlated BMI (r=0.47, 0.31, -0.25). Only in daibetic patients without angiopathy, TAT was positively correlated with HbA_1c (r=0.67). Conclusion : In this study, plasma TAT and PIC concentration significantly increased in diabetic patients compared with controls, and PIC was increased in group with microvascular complication, TAT were increased in group with combined micro macrovascular complication. However, there was no significance relationship existed when correctinf for age. PIC was correlated with HbA_1c. TAT was correlated with HbA_1c only in the group without angiopathy. Abnormality of coagulation and fibrinolysis were combined in diabetes, plasma TAT and PIC can be used as an index of vascular complication. Also we found the correlation with the degree of the blood glucose control. Therefore we need follow up study for the possibility of prevention of vascular complication after controlling the blood glucose to age-matched patients (J Kor Diaabetes Asso 25:354~363, 2001).