CFRP와 콘크리트 계면에서의 부착특성

한상훈,조홍동,박중열,황선일,김형진 충북대학교 건설기술연구소 2002 建設技術論文集 Vol.21 No.2

Externally bonding technique of CFRP(Carbon Fiber Reinforced Polymer Plate) is widely used in strengthening of concrete structures, and the improving effect of flexural strength and stiffness has been proven by early researchers. But, strengthened concrete structures present brittle failure mode accompanied with debonding of CFRP. That is, it means that the behavior of concrete structures strengthened with CFRP is mainly dependent on mechanical characteristics of CFRP and concrete interface. Therefore, double-lap shear test was performed to examine the bond characteristics on interface. The experimental variables are included with the strength of concrete, bond length and width. Test results showed that effective bond length of CFRP is approximately 30cm and maximum interfacial shear stress at specimen failure is 47 kgf/㎠.

철근콘크리트 보에 대한 CFRP의 정착길이

한상훈,최만용,조홍동,박중열,황선일 충북대학교 건설기술연구소 2002 建設技術論文集 Vol.21 No.1

A failure mode in the beam strengthened with a high modulus plate appears as a interface debonding failure or ripping-off failure. This failure mode means that plate is separated from adhesive or concrete before displaying its own ability. Therefore, as a method for controlling a premature failure, it is need to use a general anchorage implement. We conducted bending tests for reinforced concrete beams strengthened with CFRP. The experimental variables were a concrete strength, reinforcement ratio, cover thickness of concrete and length ratio of CFRP for a pure span. A failure load, failure mode, load-deflection curve and strain response at different distances from a cut-off of CFRP and strain distribution curve were measured to determine the bond development length. Also, the bond development length was compared with Nguyen’s model and British Standard specification.

Uncoupling Protein 3의 골격근 세포내 과발현이 OLETF 백서 및 배양된 골격근 세포에서 포도당대사에 미치는 영향

한정희,박혜선,고정민,김하영,강호경,이인규,박중열,홍성관,이재담,이기업 대한당뇨병학회 2002 Diabetes and Metabolism Journal Vol.25 No.6

연구배경:Uncoupling protein(UCP)는 미토콘드리아의 내막에 위치하는 단백질로 세포내의 과다한 에너지를 열로 발산시키는 기능을 가진다. 최근 동물의 갈색지방조직에만 존재하는 UCP와 유사성을 가진 아형들(UCP2,3)이 사람에게도 존재함이 알려져 큰 관심을 끌도 있는데 이중 UCP3는 그 발현이 골격근세포와 갈색지방조직에만 국한된다. 본 연구에서는 UCP3가 체내 인슐린 감수성을 결정하는데 가장 중요한 조직인 골격근에 국한되어 발현되는 점에 착안하여 UCP3를 골격근세포에 과발현시켰을 때 포도당 대사에 어떠한 영향이 나타나는 지를 조사하였다. 방법:25주령의 8마리의 OLETF 백서를 대상으로 하여 4마리는 골격근에 adenovirus 2mL(1×10¹²pfu/mL)를 주사하여 대조군으로 하였고 4마리는 골격근에 재조합법으로 제작된 adenovirus­UCP3 2mL(1×10¹²pfu/mL)를 주사하였다(UCP3 과발현군). UCP3를 투여한 백서에서 먹이섭취가 증가하는 경향이 있어 그 전날 대조군이 먹은 야의 먹이만큼 투여하였다. 골격근에 adenovirus를 주사한 10일 후에 euglycemic hyperinsulinemic clamp를 시행하였다. Adenovirus­UCP를 C2C12 골격근 세포에 transfection시켜 UCP3를 C2C12 골격근 세포에 transfection시켜 UPS3­C2C12를 만들고 C2C12 골격근 세포와 UPS3­C2C12 골격근 세포에서 포도당 수송 및 당원합성을 측정하였다. 결과:UCP3 과발현 OLETF에서 체중이 감소하는 경향을 보였고 인슐린 감수성이 증가하였다. C2C12세포에서 기저상태 포도당 수송은 1.28±0.17μmol/L/min였고 100nM 인슐린으로 2시간 처리한 후 2.67±0.20 μmol/L/min로 증가하였다. UCP3­C2C12 세포에서는 기저상태 포도당 수송이 3.98±0.13μmol/L/min로 증가되었고 인슐린 처리 후 5.74±0.44μmol/L/min로 증가하였다. 인슐린을 처리한 UCP3­C2C12 세포에 P13K 억제제인 wortmannin을 첨가하였을 때 포도당 수송활성이 3.81±0.20μmol/L/min로 감소하였다. 기저상태 당원합성은 C2C12 세포에서 0.25±0.01μmol/L/min였고 인슐린 처리 후 0.45±0.01μmol/L/min로 증가하였다. UCP3­C2C12 세포에서는 기저상태 당원합성이 0.62±0.01μmol/L/min였고 인슐린 처리 후 1.26±454μmol/L/min로 증가하였다. UCP3­C2C12세포에 wortmannin을 첨가하였을 때 당원합성율이 0.80±0.04μmol/L/min로 감소하였다. 결론:UCP3 과발현이 OLETF 백서에서 인슐린 감수성을 증가시켰고 골격근세포에서 포도당 수송 및 당원합성을 증가시켰다. wortmannin을 첨가하였을 때 포도당 수송 및 당원합성이 감소함으로 보아 이 과정이 인슐린 신호전달체계인 P13K에 일부 의존함을 알 수 있었다. Background : UC P3 is a mitochondrial membrane protein expressed selectively in the skeletal muscle and brown adipose tissue. Since the skeletal muscle is the main organ determining insulin sensitivity in the body, it was hypothesized that UCP3 overexpression in skeletal muscle cells would improve glucose metabolism. Methods : An adenovirus-UCP3 was produced by a recombinant DNA method. OLETF rats were divided into 2 groups. Four rats were injected with the adenovirus-UCP3 (UCP3 group) and others were injected with the adenovirus(control group) in the skeletal muscle. The UCP3 group was provided with the same quantity of food as that consumed by the control group on the previous day. Insulin sensitivity was evaluated by the euglycemic hyperinsulinemic clamp method. In a separate experiment, glucose transport and glycogen synthesis we evaluated in C2C212 cells transfected with ether an adenovirus or the adenovirus-UCP3. Results : The insulin sensitivity improved significantly and the body weight decreased in the UCP3 group. The glucose transport and glycogen synthesis were higher in the UCP3-C2C12 skeletal muscle cells at the basal state. After insulin treatment, glucose transport and glycogen synthesis were also higher in the UCP3-C2C12 cells but the increments were reduced after treatment with wortmannin, a PI3K inhibitor. Conclusion : Insulin sensitivity was higher in the UCP3-overexpressed OLETF rats in the in vivo study. UCP3 transfection also increased glucose transport and glycogen synthesis in the cultured skeletal muscle cells by a PI3K dependent mechanism(J Kor Diabetes Asso 25 :460~468, 2001).

탄소섬유보강판의 홈삽입에 따른 철근콘크리트 보의 보강효과

한상훈,최만용,조홍동,박중열,황선일 충북대학교 건설기술연구소 2002 建設技術論文集 Vol.21 No.1

This paper presents a feasibility study of an alternative strengthening method by slot-bonded CFRP plates for reinforced concrete beam. A total 14 reinforced concrete beam were constructed, tested and the response of the beams in terms of deflection, strains, failure load and failure mode were examined. Each specimen was initially loaded for 75% of ultimate load, cracked specimen were strengthened with CFRP plate and then tested until complete failure. Test variables included the strengthening method, steel ratio and strengthening length, and the effects according to each test variables are analysed. The experimental results show that proposed methods can increase the flexural strength and stiffness of the beam significantly. Also, the failure of the specimens strengthened by the proposed method are more ductile than externally bonded specimen.

유전알고리즘을 이용한 철근콘크리트 보의 최적설계

한상훈,조홍동,박중열,황선일 충북대학교 건설기술연구소 2002 建設技術論文集 Vol.21 No.2

This paper describes the application of genetic algorithm for the optimum design of reinforced concrete beam. The cost of reinforced concrete beam as an objective function which includes the costs of concrete, formwork, tensile steel reinforcement and shear reinforcement is minimized. The flexural and shear strength, deflection, upper-lower bounds on steel reinforcement and beam width-depth ratio are considered as the constraints. For the check of the serviceability, deflection is calculated under the service loading by the effective moment of inertia instead of the gross moment of inertia. Optimum results obtained from GA are compared to verify the validity of GA with other literature. Then, GA is applied to 3 span RC beam based on standard specifications.

NC 선반에서 직선 사이클 평면 위치결정 정도 측정 시스템의 구성

김영석,김재열,송인석,곽이구,정정표,한지희 한국공작기계학회 2002 한국공작기계학회 추계학술대회논문집 Vol.2002 No.-

It is very important to measure linear cycle plane positioning accuracy of NC lathes as they affect those of all other machines machined by them in industries. For example, if the linear cycle plane positioning accuracy of each, axes directions is had, the accuracy of works will be wrong and the change-ability will be bad in the assembly of machine parts. In this paper, computer software systems are organized to measure linear displacements of ATC(Automatic tool changer) of NC lathes using linear scale and time pulses comming out from computer in order to get data at constant time intervals from the sensors. And each sets of error data gotten from the test is expressed to plots by computer treatment and the results of linear cycle plane positioning error motion estimated to numerics by statistical treatments.

Thermal Analysis for 1.3 ㎛ High Power Laser Diodes

Jung Hwa Jung,Sang Yeol Lee,I. K. Han 한국진공학회 2007 한국진공학회 학술발표회초록집 Vol.16 No.1

Teratology Information Service in Korea: MotherSafe Center

( Jung Yeol Han ) 대한산부인과학회 2013 서울심포지움 Vol.18 No.-

Teratology Information Service, drugs, pregnancy, lactation

Fetal Loss Rate after Mid-trimester Amniocentesis

Han, You-Jung,Kim, Yun-Young,Lee, Si-Won,Kim, Min-Hyoung,Chung, Jin-Hoon,Ahn, Hyun-Kyong,Han, Jung-Yeol,Kim, Moon-Young,Yang, Jae-Hyug,Choi, Kyu-Hong,Park, So-Yeon,Ryu, Hyun-Mee Korean Society of Medical Genetics and Genomics 2012 대한의학유전학회지 Vol.9 No.1

Purpose: The aim of this study was to asses the fetal loss rate after mid-trimester amniocentesis. Materials and Methods: This was a retrospective cohort study including singleton pregnant women who underwent mid-trimester amniocentesis at Cheil General Hospital from January 2008 through December 2010. The procedure-related fetal loss was defined as miscarriage within 2 weeks after amniocentesis. We evaluated the fetal loss rate within 2 weeks after amniocentesis and fetal loss rate before 24 gestational weeks. Results: During the study period, a total of 4,356 singleton pregnant women underwent mid-trimester amniocentesis. A total of Five hundred ninety six women were excluded owing to follow up loss and termination of pregnancy due to abnormal karyotype or major anomaly. At our institute, the fetal loss rate within 2 weeks was 0.1% and before 24 gestational weeks was 0.3% after amniocentesis. Conclusion: The fetal loss rate after mid-trimester amniocentesis in our study is lower than previously reported rate. We suggest that amniocentesis is a safe procedure.

소방관의 근골격계 증상과 직무 스트레스에 관한 연구

김정만(Jung Man Kim),서병성(Byung Seong Suh),정갑열(Kap Yeol Jung),김동일(Dong Il Kim),김원술(Won Sool Kim),조한석(Han Seok Cho),김진욱(Jin Wook Kim),권재(Jae Kwon),윤동영(Dong Young Yoon),김정일(Jung Il Kim) 한국항공우주의학협회 2006 항공우주의학회지 Vol.16 No.2