우라늄 오염 금속표면의 제염을 위한 UO_2 용해특성 연구

이성열,최왕규,오원진,유승곤 한국공업화학회 2003 공업화학 Vol.14 No.3

국내의 가동 중지된 우라늄 변환시설의 해체 시 대량으로 발생될 탱크류 및 배관 등 공정 계통 부품으로 이루어진 금속 폐기물의 재팔용 또는 자체처분을 위한 현장 제염기술로 질산 제염공정을 선정하였다. 오염 물질로써 UO_2를 대상으로 UO_2 입자의 용해 거동을 통해 우라늄 화합물로 오염된 금속 폐기물에 대한 질산 용액의 표면제염 적용성을 평가하였고, 우라늄 변환시설 내에서 직접 인출한 UO_2 오염 시편의 제염 실증실험을 통해 제염 공정의 성능을 검증하였다. 질산 제염 용액에서 UO_2 입자의 용해속도는 질산의 농도 및 용액의 온도에 크게 의존하였으며, 산화제로 H_2O_2를 첨가함에 의해서 상온의 저 농도 질산 제염 용액 내에서도 H_2O_2가 첨가되지 않은 경우에 비해서 속도가 현저하게 증가되었다 UO_2로 오염된 시편의 제염에 있어서, H_2O_2가 첨가되지 않은 질산 용액 내에서의 제염계수는 α 방사능에 대해서는 1.8~2.7, β 방사능에 대해서는 1.8~2.3인 반면에 질산 용액에 H_2O_2를 첨가한 경우에는 α 방사능에 대해서 61.7~338.5, β 방사능에 대해서는 20.1~92.4를 나타냄으로써 H_2O_2를 첨가함에 의해서 상온, 저농도 질산 용액 내에서도 UO_2 오염된 금속표면을 효과적으로 제염할 수 있음을 확인하였다. In this study, a decontamination process using nitric acid was selected as an in-situ technology for recycle or disposal of large amount of metallic wastes, which includes process system components such as tanks, piping, etc that are generated as a result of dismantling retired uranium conversion facility in Korea. The applicability of nitric acid solution for surface decontamination of metallic wastes that are contaminated with uranium compounds was evaluated through dissolution of UO_2 powder. The decontamination decontamination performance are verified using UO_2 contaminated specimen that came from an uranium conversion facility. Dissolution rate of UO_2 powder was dependant considerably upon nitric acid concentration and solution temperature. Notable enhancement of dissolution rate was achieved by addition of H_2O_2 as an oxidant even in the condition of low concentration of nitric acid and low temperature. The results for decontamination of the specimen contaminated with UO_2 showed that the decontamination factors (DFs) for nitric acid solution without H_2O_2 were 1.8~2.7 and 1.8~2.3 for α and β-radioactivity. respectively, while DFs for nitric acid solution containing H_2O_2 were 61.7~338.5 and 20.1 ~92.4 for α and β-radioactivity, respectively. Thus, the metallic surfaces contaminated with UO_2 can be decontaminated effectively with low concentration of nitric acid at mom temperature in the presence of H_2O_2.

축대칭 모델을 이용한 자동차 허브 베어링의 오비탈 포밍 해석

이왕열(Wang Yeol Lee),이충안(Chung An Lee),안현규(Hyun Gyu An),이승표(Seung Pyo Lee),김헌영(Heon Young Kim) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5

돼지고기(삼겹살) 과지방 문제 해결을 위한 제안

이왕열(Wang Yeol Lee) 한국축산식품학회 2023 축산식품과학과 산업 Vol.12 No.2

후방 골편 유무에 따른 불안정 전자간부 골절의 분류 및 치료 -예비 보고-

왕립 ( Lih Wang ),손성근 ( Sung Keun Shon ),이규열 ( Kyu Yeol Lee ),김철홍 ( Chul Hong Kim ),이명진 ( Myung Jin Lee ),이철원 ( Chul Won Lee ),김성수 ( Sung Soo Kim ) 대한골절학회 2008 대한골절학회지 Vol.21 No.2

목적: 대퇴골 전자간부 골절 치료에서 골절의 양상 및 안정성을 예측하기 위해 술 전 3차원 컴퓨터 단층촬영을 시행하여 불안정 골절에 대해 추가 분류하였고 후방 골편 고정의 중요성 및 중간 치료결과에 대해 보고하고자 한다. 대상 및 방법: 2006년 10월부터 2007년 8월까지 후방 골편이 있는 불안정 골절로 진단 받고 금속정을 이용하여 치료 한 후 최소 3개월 이상 추시가 가능하였던 15예를 대상으로 하였다. 5예에서 후방 골편에 대해 경피적 도관나사 고정술을 시행하였고 (실험군), 나머지 10예는 시행하지 않았다 (대조군). 술 후 추시 방사선 평가를 통해 수술 직후와 추시 대퇴 경간각의 변화, 골절부 감입 정도를 비교 평가하였으며 합병증을 조사하였다. 결과: 대퇴 경간각은 후방 골편 고정군에 있어서 평균 3.8도, 고정을 하지 않는 군에서는 평균 7.5도의 내반 변화를 보였다. 골절부 감입은 고정군에 있어서 평균 1.6 ㎜, 고정하지 않는 군에서는 평균 6.6 ㎜의 변화를 보였다. 합병증으로는 고정하지 않는 군에서는 경부나사의 전자부 외측 돌출, 지연나사의 관절 내 돌출 및 지나친 전위로 인한 Z-현상이 각각 1예가 있었다. 결론: 대퇴 전자간부 불안정 골절에 있어서 후방 골편의 인지 및 고정은 정복 소설을 막는 데에 있어서 중요한 요소라고 생각되나 보다 많은 증례 및 장기간 추시가 필요할 것으로 사료된다. Purpose: To predict the feature and stability of intertrochanteric fractures with posterior fragment using preoperative 3D computed tomography and to investigate the importance of the posterior fragment in treatment of unstable intertrochanteric fracture. Materials and Methods: 15 cases of unstable fractures with posterior fragment which were treated with nail only between October 2006 to August 2007 were classified into 2 groups: study group (5 cases with cannulated screw fixation of posterior fragment) and control group (10 cases without cannulated screw fixation). The average difference of neck-shaft angle, neck screw sliding distance and the complications in the two groups were compared retrospectively after a follow up of at least 3 months. Results: The average difference of neck-shaft angle in study and control group was 3.8 and 7.5 degree (p>0.05), respectively. The average difference of neck screw sliding distance was 1.6 and 6.6 ㎜ (p<0.05), respectively. Complication which required reoperation was not noted in study group and complications of 3 cases about neck screw lateral protrusion, proximal migration and Z-effect phenomenon were noted in control group. Conclusion: The recognition and fixation of the posterior wall was found to be an important predictive factor in unstable inter-trochanteric fracture treatment.

Surgical site infection after debulking surgery for Korean women with advanced epithelial ovarian, fallopian tube, and primary peritoneal cancer: a multicenter retrospective study

( Da Hyun Wang ),( Eun Ji Lee ),( Soo Gui Shin ),( Heon Jong Yoo ),( Hee Seung Kim ),( Jae-yun Song ),( Yoon Jung Cho ),( Jeong-yeol Park ),( Yoo-young Lee ),( Eun-ju Lee ) 대한산부인과학회 2023 대한산부인과학회 학술대회 Vol.109 No.-

Glucotoxicity in the INS-1 Rat Insulinoma Cell Line Is Mediated by the Orphan Nuclear Receptor Small Heterodimer Partner

Park, Keun-Gyu,Lee, Kyeong-Min,Seo, Hye-Young,Suh, Ji-Ho,Kim, Hye-Soon,Wang, Li,Won, Kyu-Chang,Lee, Hyoung-Woo,Park, Joong-Yeol,Lee, Ki-Up,Kim, Jung-Guk,Kim, Bo-Wan,Choi, Hueng-Sik,Lee, In-Kyu American Diabetes Association 2007 Diabetes Vol.56 No.2

<P>Prolonged elevations of glucose concentration have deleterious effects on beta-cell function. One of the hallmarks of such glucotoxicity is a reduction in insulin gene expression, resulting from decreased insulin promoter activity. Small heterodimer partner (SHP; NR0B2) is an atypical orphan nuclear receptor that inhibits nuclear receptor signaling in diverse metabolic pathways. In this study, we found that sustained culture of INS-1 cells at high glucose concentrations leads to an increase in SHP mRNA expression, followed by a decrease in insulin gene expression. Inhibition of endogenous SHP gene expression by small interfering RNA partially restored high-glucose-induced suppression of the insulin gene. Adenovirus-mediated overexpression of SHP in INS-1 cells impaired glucose-stimulated insulin secretion as well as insulin gene expression. SHP downregulates insulin gene expression via two mechanisms: by downregulating PDX-1 and MafA gene expression and by inhibiting p300-mediated pancreatic duodenal homeobox factor 1-and BETA2-dependent transcriptional activity from the insulin promoter. Finally, the pancreatic islets of diabetic OLETF rats express SHP mRNA at higher levels than the islets from LETO rats. These results collectively suggest that SHP plays an important role in the development of beta-cell dysfunction induced by glucotoxicity.</P>

Effect of chemical dilution and the number of weld layers on residual stresses in a multi-pass low-transformation-temperature weld

Wang, Huai,Woo, Wanchuck,Kim, Dong-Kyu,Em, Vyacheslav,Lee, Soo Yeol Elsevier 2018 Materials & Design Vol.160 No.-

<P><B>Abstract</B></P> <P>Influences of chemical dilution and the number of weld layers on residual stresses in a multi-pass low-transformation-temperature (LTT) weld were investigated by finite element modelling and neutron diffraction. A coupled thermal-metallurgical-mechanical (TMM) model that took into account the chemical dilution effect was developed to simulate the complex LTT welding phenomena. The model was strictly validated by comparing the predictions with experimental measurements and the results found good agreement between them. The results showed that a transformation strain caused by LTT martensitic transformation introduced large compressive residual stresses (−500 MPa) into the weld zone and the quantities were closely related to the chemical dilution between welding layers. Simulation results revealed that the chemical dilution helped mitigate the large localized tensile residual stresses by modulating the phase transformation process and a single LTT layer was sufficient to generate high compression near the weld surface (~2.5 mm), which suggests a great importance for repair welding.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A chemical dilution model was incorporated into thermal-metallurgical-mechanical model for residual stress prediction; </LI> <LI> Chemical dilution reduces inter-layer stress buildup by modulating phase transformation; </LI> <LI> One layer of Low-Transformation-Temperature (LTT) alloy is able to generate high compression around the weld surface; </LI> <LI> The formation mechanism of residual stress in multi-pass LTT welds was clarified. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

볼엔드밀 가공시 이송변화에 따른 가공형상 특성

왕덕현,김원일,이윤경,임채열,우정윤,박창수 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.2

Due to the development of the CNC machine tool and CAM software, sculptured surface machining can be broadly used in die and mold industries and ball end milling process is often used for the sculptured surface machining. It is found out how feedrate affects the precision of the machining and also tried to study the most suitable feedrate in specific cutting condition. Two eddy current sensors were used for measuring tool deflections of X, Y axis, dynamometer for cutting force and roundness tester for roundness. It was found that the tool deflection is getting better as tool path is going to farther from the center of convex surface. The reason is that the cutting force is increased as the tool approaches to the center. Examining the roundness, cutting force and tool deflection characteristics, it was found that the most suitable feedrate is 90mm/min in convex surface and 120mm/min in concave surface.

Experimental investigation on evaporation of urea‐water‐solution droplet for SCR applications

Wang, Tae Joong,Baek, Seung Wook,Lee, Seung Yeol,Kang, Dae Hwan,Yeo, Gwon Koo Wiley Subscription Services, Inc., A Wiley Company 2009 AIChE Journal Vol.55 No.12

<P><B>Abstract</B></P><P>The evaporation behavior of urea‐water‐solution (UWS) droplet was investigated for application to urea‐selective catalytic reduction (SCR) systems. A number of experiments were performed with single UWS droplet suspended on the tip of a fine quartz fiber. To cover the temperature range of real‐world diesel exhausts, droplet ambient temperature was regulated from 373 to 873 K using an electrical furnace. As a result of this study, UWS droplet revealed different evaporation characteristics depending on its ambient temperature. At high temperatures, it showed quite complicated behaviors such as bubble formation, distortion, and partial rupture after a linear D<SUP>2</SUP>‐law period. However, as temperature decreases, these phenomena became weak and finally disappeared. Also, droplet diminishment coefficients were extracted from transient evaporation histories for various ambient temperatures, which yields a quantitative evaluation on evaporation characteristics of UWS droplet as well as provides valuable empirical data required for modeling or simulation works on urea‐SCR systems. © 2009 American Institute of Chemical Engineers AIChE J, 2009</P>

Quantitative Estimation of the Fastening Condition of a Bolt with Using Piezoceramic (PZT) Sensors

Wang, Gao Ping,Hong, Yong,Lee, Jae Jung,Hong, Dong Pyo,Kim, Young Moon,Kim, Jae Yeol Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.353-358 No.3

<P>We present a study on the development of a practical and quantitative technique for the assessment of the structural health condition with using piezoceramic (PZT) sensors. The electroimpedance- based technique with the PZT patches is very sensitive for evaluation of the incipient and small damage in a high frequency range, and however the commonly traditional modal analysis method is effective only for considerably larger damages in low frequency range. The paper presents the performance of the performance of the electro-impedance-based technique in detecting and characterizing real-time damage on the specimen that is an aluminum plate fastened with bolts and nuts by different torques. By using the special arrangement of the PZT sensors, the required longitudinal wave is generated through the specimen. A large number of experiments are conducted and the different conditions of the specimen, i.e. the location of loosening bolts and the loosening extent of bolts are simulated, respectively. Since fixing and loosening the loosened bolt is controlled by a torque wrench, we can control exactly the experiment of the different torques. Compared with the simulated healthy condition, we can find whether or not there is a damage in the specimen with using an impedance analyzer with the PZT sensors. Several indices are discussed and used for assessing the different simulated damages. As for the location of bolt loosening, the RMSD is found to be the most appropriate index for numerical assessment and as well the RMSD shows strongly linear relationship for assessing the extent of the bolt loosening. The possibility of repeatability of the pristine condition signatures is also presented and the appropriate frequency range and interval are uniquely selected through large numbers of experiments. The analytical results strongly show the sensibility and reliability of the electro-impedance based technique.</P>