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.

PVA-ECC를 활용한 Half PC 복합체의 역학적 특성에 관한 실험적 연구

김재환,김영덕,김갑수,조봉석,장종호,김무한 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2

ECC represents one particular class of HPFRCC, which are defined by an ultimate strength higher than their first cracking strength and the formation of multiple cracking during the inelastic deformation process. This study is to provide the fundamental data for the development of hybrid construction method such as the half PC(Precast concrete) reinforced by PVA-ECC, the mechanical properties of half PC according to the alteration of properties of PVA-ECC in terms of the type of fiber, Vr, S/M, placing height of PVA-ECC, are experimentally investigated. As the results. it is found that the half PCs of PVA-ECC have very higher mechanical performance in terms of yield load, strain capacity beyond yield point and maximum flexural load than that of mortar. Also, flexural crack in the half PCs of PVA-ECC are not localized at first crack and are growed to many micro crack, especially multiple cracking in specimen of P(12)-30-0.1ㆍ3 occurred.

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>

노치 형상 및 냉각속도에 따른 Zr-2.5Nb 압력관의 DHC거동

김상재,김영석,임경수,김성수,정용무 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.1

The objective of this study is to investigate the delayed hydride cracking (DHC) velocity and the incubation time for the water-quenched and furnace-cooled Zr-2.5Nb tube with the different radius of a notch tip. DHC tests were carried out at constant K_1 of 20 MPa√m and 250℃ on the cantilever beam (CB) specimens subjected to furnace cooling or water quenching after electrolytic charging with 57 or 72 ppm hydrogen, respectively. An acoustic emission sensor was attached to the CB specimens to detect the incubation time before the start of DHC. The shape of the notch tip changed from the fatigue crack to the dull crack with its radius ranging from 0.1 to 0.15 mm. The DHC incubation time increased remarkably with the increasing radius of the notch tip, which appeared more strikingly on the furnace-cooled CB specimens than on the water-quenched ones. However, both furnace-cooled and water-quenched CB specimens indicated little change in the DHC velocity with the radius of the notch tip unless their notch tip exceeded 0.125mm. These results demonstrate that the uncleation rate of hydrides at the notch tip determines the incubation time and the DHC velocity becomes constant after the concentration of hydrogen at the notch tip reaches the terminal solid solubility for dissolution (TSSD). This observation agrees well with Kim's DHC model. A difference in the incubation time and the DHC velocity between the furnace-cooled and water-quenched specimens is discussed in terms of the uncleation rate of hydrides at the notch tip and the hysteresis of hydrogen solubility.

양성 갑상선 결절에서의 무수 알코올 치료 효과

김도희,나소영,이효진,홍우정,김군순,조영석,구본정,송민호,김영건,노흥규 충남대학교 의과대학 의학연구소 2002 충남의대잡지 Vol.29 No.1

목적 : 양성 갑상선 결절 환자에서의 PEI의 치료효과 및 부작용을 알아보고자 하였다. 방법 : 양성 갑상선 결절 환자 88명을 대상으로 초음파 소견에 따라 낭종성 결절, 복합성 결절, 고형성 결절 등 세 그룹으로 분류후 전체 및 각각에 대한 PEI의 치료효과 및 부작용을 조사하였다. 결과 : 양성 갑상선 결절 환자 88명을 PEI로 치료후 결절의 크기가 50%이상 감소한 경우는 전체 환자중 77.2%이었고 각 결절별로 살펴보면 고형성 결절에서 52.6%, 복합성 결절에서 72.4%, 낭종성 결절은 92.5%이었다. 부작용은 동통, 결절내 출혈, 감염, 결절의 누출등이 있었으나 대부분 무증상이었다. 결론 : PEI는 양성 갑상선 결절 환자증 적응증을 잘 살펴 고려해 볼 수 있는 치료법이라 생각되며 특히 낭종성 결절 환자에서 주사기에 의한 흡인후에 재발한 경우 일차적인 치료로 PEI를 고려해 볼 수 있겠다. Ultrasonography(US)-guided percutaneous ethanol injection (PEI) has been performed for the treatment of autonomous functioning thyroid nodules, thyroid cysts, & cold thyroid nodules. The author studied the efficacy of PEI in the treatment of benign cold thyroid nodules both solid and cystic (complex & pure). Eighty-eight euthyroid outpatients (age:44.2±13.9years, 75 women and 13 men) with benign cold thyroid nodules or simple thyroid cysts (69 with a single nodule and 19 with a prominent nodule within multinodular goiter) were includied in this study. After PEI, each subtype of thyroid nodules was divided into three groups in according to volume reduction complete response (90% or more of volume reduction), partial response (50% or more of reducton but below 90%), and failure (below 50% or increase in size) group. Overall response rates of PEI for benign thyroid nodules were complete 45(51.1%), partial 23(26.1%), failure 20(22.7%). In 20 cold solid nodules, complete response was observed in 6(30.0%), partial response in 5(25.0%), and failure in 9(45.0%). In 28 complex cysts, complete response was observed in 8(28.6%), partial response in 12 (42.9%), and failure in 8(28.6%). In 40 pure cysts, complete response was observed in 31(77.5%), partial response in 6 (15.0%), and failure in 3 (7.5%). Side effects comprised pain 8 (9.2%), intranodular bleeding 13 (14.6%), extracapsular leakage 1(1.1%), infection 1 (1.1%), increased size l(1.1%), and none 64(72.7%). PEI may prove a safe & effective tool for the therapy of cold thyroid nodules in selected cases and may be the treatment of choice of recurrent thyroid cysts. However, further investigation involving a larger number of patients and a longer follow-up is needed.

호흡기 감염에서 Sparfloxacin 의 임상적 유용성에 대한 Enoxacin과의 비교 검토

김주옥,김선영,김관형,서지원,박석영,이종진,박성학 대한감염학회 1995 감염 Vol.27 No.4

목적:폐렴, 기관지염, 만성기관지염에서 fluoroquinolone제제로서 항균력이 강하고, 혈중 반감기가 길고, 객담과 조직내 농도가 높은 sparfloxacin의 안전성과 효과를 enoxacin과 비교하기 위해 본 연구를 시행 하였다. 방법:1994년 10월부터 1995년 4월까지 충남대 부속병원과 대전 성모병원에 내원한 폐렴, 급성기관지염, 만성기관지염이 급성으로 악화된 환자 63명을 대조군(32명)(enoxacin 100 mg 1일 3회 경구투여), 실험군(31명)(sparfloxacin 200mg 1일 1회 경구투여)으로 나누어 임상증상, 세균학적 객담 검사, 혈액검사, 실험실내 항균력검사로 그 치료율 및 안전성을 비교하였다. 결과: 1) 임상종합 평가, 세균학적 균소실, 안전성, 유용성에서 두군간에 의미 있는 차이는 없었다. 2) 시험관내 항균력검사상 MIC가 실험군이 대조군보다 현저하게 낮았다.(p<0.05). 3) 경미한 두통, 식욕감퇴, 상복부 불쾌감, 설사등이 대조군 9예, 실험군 7예에서 발생하였고, 검사실 소견상 SGOT 혹은 SGPT 의 일시적 경미한 상승이 대조군 2명, 실험군 3명에서, 혈중 creatinine 상승이 실험군 2명에서 있었으나 경미하였다. 결론:이상의 결과로 sparfloxacin은 폐렴, 급성기관지염, 만성기관지염의 악화에서 하루 한번 투여로 enoxacin 하루 3번 투여와 유사하게 효과적이고 안전하며, 시험관내 항균력이 enoxacin보다 월등히 우수하여 임상에서도 유용하게 사용될수 있을것으로 생각된다. Background: Sparfloxacin, a new oral quinolone, has a broad spectrum, potent antimicrobial activity, prolonged half life, high concentration in sputum. The clinical efficacy and safety of sparfloxacin have been reported by some previous clinical studies performed in Japan. The objectives of this study were to evaluate the clinical and antimicrobial efficacy of this drug in respiratory tract infections compared to those of enoxacin. Methods:We performed an open controlled, randomized study in 63 patients with acute bronchitis, pneumonia, and exacerbation of chronic bronchitis at Chung Nam University hospital and Dae Jeon St. Mary's hospital from October, 1994 to April, 1995. In the control group(n=32), 100 mg enoxacin was administered orally 3 times a day and in the test group(n=31), 200 mg sparfloxacin once a day. Results: The results were as follows; 1) There were no significant differences between the two groups in clinical efficacy, bacteriological finding, and usefulness. 2) Means and SD of MICs were 0.44±0.89 ㎍/ml in the control group, 0.13±0.24 ㎍/ml in the test group. There was a significant difference in MICs between the two groups(p<0.05). 3) Headache, epigastric discomfort, and loss of appetite were observed in 7 cases of the control group and in 9 cases of the test group, and transient elevations of hepatic enzyme in 2 cases of the control group, and in 3 cases of the test group. There was mild elevation of serum creatinine in 2 cases of the test group. Those laboratory abnormalities by therapy might be associated with their underlying diseases. There were no significant adverse effects caused by the drugs Conclusion:In conclusion, sparfloxacin of 200 mg once a day was as effective and well tolerated as enoxacin of 100 mg three times per day in the treatment of respiratory tract infections. Sparfloxacin is more potent antibiotics because MICs of sparfloxacin were very lower than those of enoxacin.

網膜色素上皮細胞의 Lysosomal acid phosphatase의 活性値 測定

김복희,김은경,김윤화,백미화,이지숙,조영숙,황응숙 曉星女子大學校 藥學大學 學生會 1988 曉星藥誌 Vol.4 No.-

Measurement of lysosomal enzyme activity in the rabbit eye was effected using acid phosphatase as enzyme markers. Acid phosphatase in the retinal pigment epithelium of the rabbit eye was studied using standard enzymological techniques. The enzyme activity in the lysosomal extract of the pigment epithelium was 54.9±23.0 King-Armstrong Unit/dl.

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.

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.

Characterization of the isotropic-distortional hardening model and its application to commercially pure titanium sheets

Pham, Quoc Tuan,Lee, Myoung Gyu,Kim, Young Suk Pergamon Press 2019 International journal of mechanical sciences Vol.160 No.-

<P><B>Abstract</B></P> <P>Commercially pure titanium sheets have been widely used in various industrial applications owing to their lightweight nature, superior formability, and excellent corrosion resistance. Previous studies showed that accurate modelling of material characteristics, such as anisotropic yield function and hardening, is essential for the simulation of sheet metal forming with titanium sheets. For example, the non-quadratic anisotropic yield function Yld2000-2d and the modified Kim–Tuan hardening model were used to model initial anisotropy and reproduce flow stress curves at large strains. However, even with these advanced constitutive models for describing the anisotropic behavior of sheet metals, further improvement is necessary to simulate anisotropy evolution, or distortional hardening, in pure titanium sheets. In this study, distortional hardening was experimentally measured under both uniaxial and balanced biaxial loading conditions. Moreover, the evolution of the Yld2000-2d function was modelled as a function of equivalent plastic work. For validation, the developed material models were applied in finite element simulations to analyse deformation behavior in uniaxial tension, hydraulic bulge, and punch-stretching tests. It was confirmed that this approach accurately described material response during these three tests.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Experimental observation of distortional hardening behaviour and three-stage deformation behavior for a pure titanium sheet. </LI> <LI> A procedure to reproduce these material behaviours for the tested material by using an evolutionary yld2000-2d yield function and modified Kim–Tuan hardening law. </LI> <LI> Simulation results of uniaxial tensile tests, hydraulic bulge test, and punch-stretching tests match well with experimental data. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>