Critical Temperatures for Initiating and Arresting Delayed Hydride Cracking in a Zr-2.5Nb Pressure Tube

Kim, Young Suk,Im, Kyung Soo,Cheong, Yong Moo Trans Tech Publications, Ltd. 2005 Key Engineering Materials Vol.297 No.-

<P>The hydrogen concentration limit and critical temperatures for a delayed hydride cracking (DHC) in zirconium alloys have been reanalyzed using Kim’s DHC model that a driving force for DHC is not the stress gradient but the supersaturated hydrogen concentration or ∆C arising from a hysteresis of the terminal solid solubility on a heating and on a cooling. The DHC initiation occurs generally at the temperatures corresponding to the terminal solid solubility for precipititation (TSSP), demonstrating that the supercooling from the terminal solid solubility for dissolution (TSSD) is required to initiate the DHC. The DHC arrest temperatures correspond to the temperatures where the ∆C is reduced to zero. Therefore, we conclude that the ∆C is the driving force for the DHC and that the Kim’s DHC model is feasible.</P>

생체분해성 망막압정을 이용한 망막고정에 대한 실험적 연구

김용백,민병무,김창식,박근성,김승영,길숙종,조항진,이성복,노승무,송규상,강대영,조준식,양준묵,정경수,최선웅,이진호,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

Biodegradable retinal fixation devices obtain mechnical fixation of the retina with desirable chorioretinal scarring and with the potential for local, sustained release of antimetabolites and steroids to inhibit proliferative vitreoretinopathy. We manufactured a biodegradable retinal tack with barb that was designed in order to prevent intrusion from implantation of retinal tacks. This study was carried to evaluate the efficacy for retinal fixation and the capability for sustained release of drugs with a newly designed biodegradable retinal tack Biodegradable retinal tacks were made of polymers of glycolic acids and were designed with barbs in a shape to prevent the disinsertion. Biodegradale retinal tacks are divided into 3 parts, a conical portion that is inserted into the sclera, a cylinder portion that remains in the vitreous, and a neck portion between the pin and the cylinder. The tapered conical end was manufactured to allow easy insertion through the retina and choroid into the sclera. A cylinder portion was manufactured with a tapered angle that fixes firmly into the orifice of 19 gauge spinal needle. A neck portion, 0.4 mm in diameter, was designed to prevent disinsertion from following implantation of retinal tack. The applicator was a 19 gauge spinal needle and its orifice was prepared to 15°angle to accept the tapered cylinder portion of the retinal tack. The retinal tacks, secured in the needles, were passed through the formed vitreous and inserted into the retina, choroid, and sclera and were released by pushing the internal needle, usually within 2-3mm of the medullary ray of the posterior rabbit retina A retinal tack was placed in each of 8 pigmented rabbit eyes. Slit-lamp biomicroscopy, indirect ophthalmoscopy and fundus photography were performed periodically from 1 day to 8 weeks after surgery. Eight eyes were enucleated and studied by light microscopy at 8 weeks. Biomicroscopic evaluation of the animals revealed edemas adjacent to the retinal surfaces immediately after insertion of the biodegradable retinal tacks in all the animals. These edemas disappeared after 1 week. The first noticeable change in the size of retinal tacks was shown after 2weeks. The size of the retinal tacks gradually got smaller, decreasing to about one-half at 4 weeks and about one-third at 8 weeks. All retinal tacks remained in inserted places without any movement for an 8 week period. On light microscopy, epiretinal proliferations were seen to extend into the vitreous cavity. Cellular capsules that lined the inner aspect of the scleral defect caused by tack insertion were found. However the adjacent retina had a normal cytologic appearance and architecture in all specimens. We manufactured a biodegradable retinal tack that is designed to prevent intrusion from implantation of retinal tacks. All biodegradable retinal tacks reduce in size with time, but no retinal tacks extruded from the inserted place. The newly designed biodegradable retinal tack can be used for retinal fixation and may be used as a vehicle for the introduction of pharmacologic agents to prevent the cellular events that promote proliferative vitreoretinopathy.

전문대학 간호과 통합교과과정 개발에 관한 연구

김영희,김정수,김정애,방숙명,배경진,이애경,장은정,정안순,주미경,최나영 경복대학 1998 京福論叢 Vol.2 No.-

교과과정의 조직은 체계적이고 뜻이 있는 순서로 학생들을 가르치기 위해 지식을 어떻게 조직화할 것인지와, 과목들 사이에서 공통된 내용은 통합시켜 중첩되는 일이 없도록 조정할 필요가 있다. 이에 현재 본 대학 간호과에서 운영되었던 97학년도의 17개 전공과목들의 교과과정의 내용을 비교, 분석하여 중복을 줄이며 순차적 지식의 습득을 도모하는 새로운 통합교과과정의 틀을 개발, 제시함으로써 보다 나은 전문직 간호교육이 이루어지도록 하고자 하였다. Most curricula are considered how to teach the student in systematic and meaningful orders. And it is necessary to coordinate the duplicate contents in major subjects in nursing. So this study was designed to set up a new comprehensive curriculum through comparing and ananlyzing each seventeen major subjects in Nursing Department of Kyung-Bok College. Therefore, the purpose of this study is to present the new comprehensive curricula for promoting the efficiency and effectiveness in diploma degree course of nursing education.

복합열화환경 하에서의 단면복구재의 철근부식특성 평가에 관한 실험적 연구

김영덕,박종호,조봉석,김용로,권영진,김무한 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1

The duties of the restorative material are to bear up against stress and to protect reinforcement corrosion. So the restorative material are estimated by various kinds of strength, permeability and etc. But to evaluate performance of the restorative material accurately, it is necessary to estimate their reinforcement corrosion directly in environment of combined deterioration. In this study, to evaluate performance of restorative materials, we compare their properties in terms of compressive and bending strength and permeability of water and air with actual reinforcement corrosion like ratio of corrosion area, weight reduction and corrosion velocity of steel bar under environment of complex deterioration. The results showed that strength and permeability of restorative materials are similar but their reinforcement corrosions are very different. And there is a case that strength and permeability of restorative material are better than normal concrete but reinforcement corrosions are worse.

New Stress-Strain Model for Identifying Plastic Deformation Behavior of Sheet Materials

김영석(Young Suk Kim),팜콕트완(Quoc Tuan Pham),김찬일(Chan Il Kim) Korean Society for Precision Engineering 2017 한국정밀공학회지 Vol.34 No.4

In sheet metal forming numerical analysis, the strain hardening equation has a significant effect on calculation results, especially in the field of spring-back. This study introduces the Kim-Tuan strain hardening model. This model represents sheet material behavior over the entire strain hardening range. The proposed model is compared to other well known strain hardening models using a series of uniaxial tensile tests. These tests are performed to determine the stress-strain relationship for Al6016-T4, DP980, and CP Ti sheets. In addition, the Kim-Tuan model is used to integrate the CP Ti sheet strain hardening equation in ABAQUS analysis to predict spring-back amount in a bending test. These tests highlight the improved accuracy of the proposed equation in the numerical field. Bending tests to evaluate prediction accuracy are also performed and compared with numerical analysis results.

Review on Critical Temperatures for Initiation and Arrest of Delayed Hydride Cracking in Zirconium Alloys

Young Suk Kim,Kyung Soo Im,Yong Moo Cheong 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.8

The hydrogen concentration limit and critical temperatures for a delayed hydride cracking (DHC) in zirconium alloys have been described on the assumption that a tensile stress gradient is a driving force for the DHC. By correlating the DHC initiation and arrest temperatures with the critical supersaturated hydrogen concentration or △C for the DHC initiation and arrest, we conclude that the △C arising from the hysteresis of the terminal solid solubility of hydrogen on a heat-up and on a cool-down is the driving force for the DHC and that the Kim's DHC model is feasible.

Temperature Dependence of Delayed Hydride Cracking Crack Velocity in Zr-2.5Nb Tubes

Young Suk Kim(김영석) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11

Delayed hydride crack tests were conducted on Zr-2.5Nb tubes with different distributions of the β-Zr at temperatures ranging from 125 to 300 ℃. Compact tension specimens charged to 27 to 100 ppm hydrogen were used to determine temperature dependences of their DHC velocity (DHCV) and striation spacing. The Zr-2.5Nb tube with a higher yield strength and a seimi-continuous β-Zr has a higher DHCV and a smaller striation spacing than that with a fully discontinuous β-Zr and a lower yield strength. It is found that the activation energy for the DHCV is the sum of the activation energy for hydrogen diffusion and the striation spacing representing the hydrogen concentration gradient at the crack tip. Quantitative contribution of hydrogen diffusion nad the hydrogen concentration gradient to the DHCV is discussed. This study provides supportive evidence to the feasibility of Kim’s DHC model.

여가활동 유형이 여가만족에 미치는 영향

김의영,김의영,김영숙,윤대중,이병기 龍仁大學校 武道硏究所 2002 武道硏究所誌 Vol.13 No.1

This research is designed to make a comparative analysis of the types of leisure activities and the degree of leisure satisfaction by demographic background variable and to present basic materials necessary for the development of programs for local policies on leisure in accordance with the local autonomous system with a view to determining the relationship between leisure and life satisfaction by type of leisure activity. The following are the findings. First, the survey on testing the difference of leisure satisfaction by gender failed to test the difference in psychological and physiological satisfaction, but there were a statistically significant difference in educational, social and relaxation satisfaction at a level of 1 percent. And the survey failed to test the difference in psychological satisfaction by age, but there was a statistically significant difference in leisure satisfaction by society, education, job, monthly income, and health. Second, the survey on the influences of the types of leisure activities on leisure satisfaction revealed that there was a statistically significant influences in all the subordinate variables of leisure satisfaction.

HMG-CoA 환원효소 억제제에 의한 ICAM-1 유전자의 발현조절

김현진,정효균,홍우정,김군순,조영석,김도희,채수흥,구본정,송민호,노흥규,김영건 충남대학교 의과대학 지역사회의학연구소 2001 충남의대잡지 Vol.28 No.1

Background : ICAM-1 act as one of major adhesion molecules in the atherosclerotic lesion. ICAM-1 expression is mainly regulated at the level of transcription and depend on IFN-γ signal transduction pathway in which the STAT1 transcrption factor is a critical intermediate. IFN-γreceptor not only initiates tyrosine 701 phosphorylation of STAT1 by Jak1 and Jak2, but also phosphorylates serine 727 through the activation of Raf-1/MAP kinases. HMG-CoA reductase inhibitors have anti-atherosclertic effects, beyond normalization of hypercholesterolemia, by directly acting on endothelial cells, macrophages and vascular smooth muscle cells. HMG-CoA reductase inhibitors suppress the synthesis of isoprenoid intermediates such as geranylgeranyl-pyrophosphate or farnesylpyrophosphate. These effects results inhibitors suppress the synthesis of isoprenoid intermediates such as geranylgeranyl-pyrophosphate or farnesylpyrophosphate. These effects results inhibition posttranslational farnesylation and geranyl-geranylation processing of small GTP-binding preoteins and inhibition of normal signaling activities. Method : We made several 5'-deletion constructs of rat ICAM-1 promoter and analyzed the promoter activities by measuring the luciferase activity after transfection into ECV304 cells and smooth muscle cells. We checked the level of total and phosphorylated STAT1 protein by immunoblot analysis using specific antibodies. Results : Lovastatin inhibits IFN-γ-induced ICAM-1 gene expression in the ECV304cell. The cells pretreated with PD98059, MEKK inhibitor showed significantly low ICAM-1 RNA induction with IFN-γ stimulatio. IFN-γ induced phosphorylation of tyrosine 701 was not significantly changed by the pretreatment of lovastatin. But lovastatin suppresses IFN-γ-induced phosphorylation of ERK1/ERK2 which are responsible for the seine 727 phosphorylation in STAT1. Conclusion : We showed that HMG-CoA reductase inhibitors, lovastatin, suppresses IFN-γ mediated ICAM-1 gene expression through the inhibition of transcription. HMG-CoA reductase inhibitor suppresses IFN-γ-induced phosphorylation of serine 727 in STAT1 through the modulation of MAP kinases.

자가 말초혈액 조혈모세포 이식술의 임상적용

김혁,안명주,오석중,이영열,김인순,정태준,최일영,오미란,임호준,이항,김신규 한양대학교 의과대학 1999 한양의대 학술지 Vol.19 No.1

Responses to chemotherapy correlate with the increased dose of chemotherapeutic agents in some cancers, e.g. breast cancer, Ewing's sarcoma, Hodgkin's disease(HD) and non-Hodgkin's lymphoma(NHL), then for the improvement of the chemotherapy responsiveness, high-dose chemotherapy(HDCT) was proposed. But, it's application was limited due to complications, especially bone marrow suppression. HDCT and succeeding autologous peripheral blood stem cell transplantation(APBSCT) was introduced to overcome this problem. This study was designed to determine the clinical pictures including clinical parameters and the responsiveness of HDCT followed by APBSCT in Hanyang University Hospital. Ten patients were enrolled. They were 8 adults (3 breast cancers, 3 multiple myelomas, 1 HD, 1 NHL) and 2 children (1 acute myelogenous leukemia (AML), 1 neuroblastoma). Mobilization chemocherapy(MCT) followed by Granulocyte Colony Stimulating Factor(G-CSF) was administered to mobilize stem cells from bone marrow to peripheral blood. The stem cells were collected by using CS-3000 and cryopreserved at -196℃ with programmed controlled rate freezer as the mixture with 10% dimethyl sulfoxide(DMSO). HDCT was administered and cryopreserved peripheral stem cells were infused on day 0 as planned. Patients' mean age was 41 years old. After induction chemotherapy three patients achieved complete response and 5 partial response. The median time for bone marrow recovery after MCT was 11.5 days for neutrophil(〉500/㎣) and 4.8 days for platelet(〉20,000/㎣). There were three cases of neutropenic fever and one case of gingivitis. After HDCT with APBSCT, one patient was converted partial response to complete response, and one patient achieved complete response after HDCT without induction chemotherapy. The median time for bone marrow recovery was 12.7 days for neutrophil(〉500/㎣) and 14.7 days for platelet(〉20,000/㎣). Eight patients developed neutropenic fever and required systemic antibiotics. Transfusion was required 1.6 pints for packed red cell and 23.4 pints for platelet concentrates. Toxicity consisted mainly of vomiting, diarrhea, and mucositis which were mild. HDCT with APBSCT can be performed safely with minimal complications. For the evaluation of the exact role of HDCT with APBSCT in malignant diseases, further studies are required as a large scale of patients and lung-term follow up.