Plastic기 복합재료의 파손강도 및 파괴인성에 미치는 원공크기의 영향

김정규,김도식,Kim, Jeong-Gyu,Kim, Do-Sik 한국재료학회 1993 한국재료학회지 Vol.3 No.2

Plastic기 복합재료의 파괴거동에 미치는 원공크기오 판폭의 영향을 검토하기 위하여 단축인장시험을 행하였다. 점응력파손조건에서의 특성길이 $d_o$는 원공크기 및 판폭에 의존하며, 이를 기초로 파손강도를 예측하기 위한 수정 점응력 파손조건식을 제안하였다. 이 파손조건의 예측값은 실험값과 잘 일치하였다. 파손 강도는 원공선단의 손상비의 증가에 따라 증가하며, 이는 손상영역의 형성으로 인한 응력완화현상으로 설명되어 진다. 또한 불안정 파괴시의 최대균열길이 $a_c$는 특성길이 $d_o$의 약 2배의 값을 나타낸다. 파괴인성에 대응하는 한계에너지해방율 $G_c$의 변화는 원공선단의 손상영역의 증가에 의한 응력완화가 주요한 원인이라고 할 수 있다. Abstract The effects of the hole size and the specimen width on the fracture behavior of several fabric composite plates are experimentally investigated in tension. Tests are performed on plain woven glass/ epoxy, plain woven carbon/epoxy and satin woven glass/polyester specimens with a circular hole. It is shown in this paper that the characteristic length according to the point stress criterion depends on the hole size and the specimen width. An excellent agreement is found between the experimental results and the analytical predictions of the modified failure criterion. The notched strength increase with an increase in the damage ratio, which is explained by a stress relaxation due to the formation of damage zone. When the unstable fracture occurred, the critical crack length equivalent for the damage zone is about twice the characteristic length. The critical energy release rate $G_c$ is independent of hole size for the same specimen width. The variation of $G_c$ according to the material system, fiber volume fraction and specimen width relates to the notch sensitivity factor. $G_c$ increases with a decrease in the notch sensitivity factor, which can be explained by a stress relaxation due to the increase of damage zone.

운동으로 유도된 근손상이 안정시 대사량과 혈중 카테콜라민 농도에 미치는 영향

김정규(Kim Jung-Kyu),최용철(Choi, Yong-Chul) 한국체육과학회 2014 한국체육과학회지 Vol.23 No.1

The aim of this study was that effect of exercise-induced muscle damage(EIMD) on resting metabolic rate and blood catecholamines concentration. Eight subjects(age 24.4±2.l0 years, Height 176.4±5.80 ㎝, Weight 73.6±8.80 ㎏, % body fat 23.5±3.55 %, VO₂max 5O.9±4.00 ml/㎏/min) were completed three resting metabolic rate(RMR) measurements, one maximal exercise work load test, and one eccentric exercise(downhill running for 30min at -12% grade of treadmill). The blood was collected for assay the creatine kinase(CK) and catecholamines (epinephrine and norepinephrine).<br/> There were significant differences in RMR which were calculated by day, body weight, fat free mass following the EIMD(p<.05). Also there were significant differences in resting oxygen consumption, RER, muscle soreness scale, and blood creatine kinase activity following the EIMD(p<.05). However, there were no significant differences in blood catecholamines(epinephrine and norepinephrine) concentration following the EIMD(p>.05). In conclusion, this study showed that in the presence of exercise-induced muscle damage energy expenditure, expecially resting metabolic rate(RMR) is increased before having muscle damage. The index of muscle damage(creatine kinase) also have related to the RMR after exercise-induced muscle damage. It was suggested that EIMD may be either metabolic or mechanical, or combination of both, depending upon exercise type, intensity and duration and training status. Also we need to study about the mechanism for the oxygen consumption following EDMI with the resonable research tools, such as, hormonal changes and energy substrate utilization.

[論文] 複合組織鋼의 機械的特性에 미치는 微視組織因子의 영향

김정규(J.K.Kim),유승원(S.W.You) 한국자동차공학회 1987 오토저널 Vol.9 No.3

<br/> A study has been made to clarify the microstructural effect On static tensile properties of the dual phase steel, in which the martensitic phase encapsulated islands of ferritic phase.<br/> The main results are as follows:<br/> Yield strength is associated with the degree of plastic constraint factor and tensile strength increases with increasing of strain hardening exponent. Also, the variation of ductility is dependent upon the amount of micro-brittle facets.

응급의료기관 내 폭행 등 범죄예방을 위한 민간경비 활성화 방안

김정규(Kim jung-gyu) 한국콘텐츠학회 2019 한국콘텐츠학회 종합학술대회 논문집 Vol.2019 No.5

흙막이 구조물의 관리기준치 수정계수에 관한 연구

김정규(Juengkyu Kim),박흥규(Heungkyu Park) 한국지반환경공학회 2014 한국지반환경공학회 학술발표회논문집 Vol.2014 No.9

[論文] 複合組織鋼의 衝擊破壤特性에 미치는 노치形狀 및 硬度比의 영향

김정규(J.K.Kim),유승원(S.W.You),김일현(I.H.Kim) 한국자동차공학회 1988 오토저널 Vol.10 No.2

Effect of Notch Shape and Hardness Ratio on Characteristics of Impact Fracture in Dual Phase Steels.<br/> In this study, it is investigated the effect of notch shape and hardness ratio on the charac-teristics of impact fracture in dual phase steels. The impact test was carried out at the tempera-ture range from -40℃ to room temperature with Instrumented Charpy Impact Tester.The main results obtained are as follows;<br/> 1.The maximum impact bending strength(σ_max)increases with the tensile strength. Also, the impact enerty depends on σ_max.<br/> 2.In room temperature, the impact energy depends on crack-initiation energy(E_i)in case of the high hardness ratio (R=3.4), whereas depends on crack-propagation energy(E_p)in case of the low hardness ratio(R=1.8)and the dependence of crack-initiation energy of the impact characteristics decreases with increasing test temperature.These phenomena are results from the difficulty of cleavage facet formation.

임신 2기의 임신중절에서 misoprostol과 sulprostone의 임상적 효용성 비교

김정규 ( Jeong Kyu Kim ),문종필 ( Jong Pil Moon ),김용범 ( Yong Beom Kim ),지일운 ( Ill Woon Ji ),정은환 ( Eun Hwan Jeong ),김학순 ( Hak Soon Kim ) 대한산부인과학회 2002 Obstetrics & Gynecology Science Vol.45 No.12

목적 : 임신 2기의 유산에 있어서 misoprostol과 sulprostone의 임상적 효용성을 비교해 보고자 하였다. 연구 방법 : 임신 2기에 유산을 요하는 환자들을 misoprostol군과 sulprostone군으로 무작위로 배정한 후, 임신 20주를 기준으로 각각 다시 세분하였다. Misoprostol군에서 임신 20주 이하는 misoprostol 400 킽을 4시간마다 질내에 삽입하였고, 임신 20주 이후에는 200 킽을 6시간마다 삽입하였다 Objective : Our purpose was to compare the clinical efficacy of intravaginal misoprostol and that of intravenous sulprostone for termination of second-trimester pregnancy. Methods : The patients were assigned to misoprostol and sulprostone group, and the

청소년 음주에 관한 원인 분석

김정규(Jeong-Gyu Kim) 한국사회학회 2009 韓國社會學 Vol.43 No.5

이 연구는 청소년의 음주와 종교성과의 관계를 조명하기 위해 1,139명의 인문계 고등학생을 대상으로 한 설문조사를 바탕으로 개신교, 천주교, 불교 각각의 음주에 대한 종교의 영향력의 차이를 검증하였다. 종교의 영향력을 분석하기 위해 종교성을 신앙심과 참여빈도로 각각 나누어 살펴보았다. 분석 결과 음주에 대한 종교적 금지가 상대적으로 강한 개신교 청소년들의 경우 신앙심이 깊을수록 술을 덜 마시는 반면, 천주교와 불교는 신앙심과 음주와의 관계가 발견되지 않았다. 이러한 결과는 음주에 영향을 미칠 수 있는 다양한 변인들, 즉 부모, 학교와 성적, 자아통제, 친구 등과 같은 변인들을 통제하고도 나타났다. 따라서 개신교도이면서 신앙심이 높은 경우 다른 변인들을 통제하더라도 영향력이 줄어들거나 사라지지 않은 결과를 보임으로써 연구의 가설이 지지되었다고 할 수 있다. 한편 종교성의 효과는 단지 신앙심으로 종교성을 측정했을 때만 유의미하게 나타났고, 참여빈도로 측정했을 경우 전혀 그 영향력이 없었다. 서구에서 특히 미국을 중심으로 행해진 종교성에 대한 연구는 대부분이 기독교적인 종교적 배경을 지닌 것에 중점을 두었기 때문에 신앙심과 참여빈도를 함께 종교성의 주요 측정자로 사용하기에 큰 문제가 없을 수 있다. 그러나 불교와도 같이 종교적 교리와 신조, 신앙의 기준 등이 상이한 종교에서도 일률적인 측정자를 사용하는 것은 상당한 문제가 따를 수 있다. 그러므로 종교성을 측정하는데 있어서 미국식 기독교 중심의 종교성을 측정하는 도구를 우리나라에 사용할 경우에는 상당한 주의가 필요하다. Using questionnaire data from a sample of 1,139 adolescents, this study examines the effect of religiosity on adolescents' alcohol use. Beyond a simple bivariate relationship, this study analyzes whether the effect of religious beliefs and frequency of religious institution attendance vary according to religious affiliation of adolescents, such as protestant, catholic, and buddhism. The results show that religious beliefs decrease adolescents' alcohol use rates only in protestant group which emphasizes negative attitudes toward alcohol use. The statistical significance of religious beliefs is still maintained when other variables are included in the equation, such as parents, school, grades, self-control and peer variables. However, the effect of religious beliefs on alcohol use is not found in catholic and buddhism group. On the other hand, the effect of church or temple attendance is not found in all groups. These results imply that adolescents who have a strong religious belief are more likely to have negative attitudes and less involved in drinking behaviors only in protestant group. In doing so, religiosity influences adolescents' alcohol use differentially depending on religious affiliation of adolescents. Also, this study suggests that frequency of religious institution attendance as a measure of religiosity should be used very carefully according to social context and religious affiliation.

온라인 플랫폼 공정화법 정부안의 제정효과 추정을 위한 비용편익분석 - 중개거래계약서 작성·교부 의무와 불공정거래행위금지 규정 신설을 중심으로 -

김정규(Kim Jeongkyu),유성희(Yoo Seonghee) 과학기술정책연구원 2021 과학기술정책 Vol.4 No.2

운동이 비만을 동반한 제2형 당뇨병 환자들의 HOMA-IR, Adipokine 및 염증반응에 미치는 영향

김정규(Kim, Jung-Kyu) 한국체육과학회 2017 한국체육과학회지 Vol.26 No.4

The purpose of this study was to examine the effects of exercise on HOMA-IR, adipokine and inflammatory response in Type 2 diabetes with obesity. Ten diabetes non-obese subjects(DNO group: age 53.6±2.44, height 173.0±2.45, weight 80.6±0.99, % body fat 24.1±1.69, BMI 26.9±1.02 kg/m², disease duration 4.24±0.13 years) and ten diabetes obese subjects(DO group: age 53.4±1.11, height 164.0±3.56, weight 87.9±2.56, % body fat 30.2±2.47, BMI 32.8±2.13 kg/m², disease duration 5.79±0.27 years) volunteered to take part in this study. The experiments were performed after taking consent form from each subjects. Exercise program was walking on the treadmill for 30 min 3 days a week during 8 weeks. Body weight, BMI, and % body fat showed significant difference between group(p〈.05). Blood level of glucose and HOMA-IR decreased after 8 weeks walking program in both groups(p〈.05), however there was no significant difference between group(p〉.05). The blood level of TNF-α decreased after 8 weeks walking program in DNO group(p〈.05), but there were no significant difference between group(p〉.05). The blood level of adiponectine decreased after 8 weeks walking program in both groups(p〈.05), but there were no significant difference between group(p〉.05). In conclusion, regularly aerobic walking exercise have positive effects on insulin resistance and metabolic role of adipokine in Type 2 diabetes with or without obesity.