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>

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.

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.

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.

Delayed Hydride Crack Velocity of Zirconium Alloys with the Direction of an Approach to Temperature

KIM, Young Suk,KIM, Kang Soo,CHEONG, Yong Moo Atomic Energy Society of Japan 2006 Journal of nuclear science and technology Vol.43 No.9

<P>The delayed hydride cracking (DHC) tests were conducted on Zr-2.5Nb compact tension specimens with the test temperatures reached by a heating and a cooling. The Zr-2.5Nb specimens were either furnace-cooled or water-quenched after a hydrogen charging treatment to contain 10 to 100 ppm H. On an approach to the test temperatures by a cooling, both the Zr-2.5Nb specimens showed the DHC velocity increasing with an increasing temperature over a temperature range of 100–300°C, irrespective of the cooling rate. However, on an approach to the test temperatures by heating, the furnace-cooled Zr-2.5Nb showed a DHC arrest at temperatures over 180°C and no DHC at 250°C, and the water-quenched ones did have a DHC growth, even at 250°C. Using Kim’s DHC model we elucidate the DHC arrest in the furnace-cooled Zr-2.5Nb at temperatures over 180°C and the DHC growth in the water-quenched specimen, even at 250°C, upon an approach by a heating.</P>

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>

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.

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.

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.

남자 고등학교 세팍타크로 경기의 공격기술에 관한 분석 연구

김영호,고문석,제임스전,이영익,차정훈,현종건,김범수,임종만,이석인 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.6

This research aims at analysis of attack technique in sepaktakraw games. For this purpose, 3 high school coaches observed and recorded each game Five times in videos of high school male players' thirty games in 2003. The conclusion from the analysis of the recorded data are as follows. 1. Scissors spike was the most popular (favorite) attack technique. Rolling spike, tapping spike and heading spike was popular in order. 2. Heading spike showed the highest success rate (73.5%) in attack technique. And tapping spike (69.5%), scissors spike (57.8%) and rolling spike (67.11) showed a lower success rate in order. In failure rate, heading spike (5.5%), tapping spike (36.5%), scissors spike (32.2%) and rolling spike (32.9%) had a higher percentage in order. 3. When receive was stable, the success rate in attach technique was 47.1%, the failure rate was 20.1%. On the other hand, when receive was unstable, the success rate in attach technique was 16.5%, the failure rate was 14.3%.