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포스트-텐션 프리캐스트 외부 넓은 보-기둥 접합부의 비탄성 거동
박상욱,최윤철,김영찬,김대중,임재형,권기혁,문정호,이리형 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2(구조계)
Experimental results from the cycle lateral load tests for post-tensioned precast wide beam-column connections were presented. Six exterior beam-column assemblages of half scale were tested in the laboratory. The specimens consist of U-shaped precast wide beams and concrete columns. The continuity at the beam-column joint is achieved with the topping concrete and post-tensioning. The specimens were designed with parameters of the beam-to-column depth ration and the number of tendons within column core. The test results showed that the post-tensioned precast wide beam-column connection satisfied the provisional standard by ACI of acceptance criteria for concrete special moment frames.
프리캐스트 포스트텐션 콘크리트 넓은 보-기둥 내부 접합부의 비탄성 거동
황재환,최윤철,김영찬,김대중,임재형,권기혁,문정호,이리형 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2(구조계)
The purpose of this paper is to evaluate the response of Precast Prestressed Concrete Interior Wide Beam-Column Joint subjected to cyclic lateral loading. To this end, the experimental investigation was performed with six half-scale specimens of interior connection. The design parameters are the beam to column depth ratio, and the number of tendons within column core. One of the specimens, IJH-6, is modeled for the connection at the top floor of a structure. The test results showed that the specimens sufficiently resist up to limiting drift ratio of 0.035 in accordance with the provisional standard by ACI of acceptance criteria for concrete special moment frames.
Joong-Cheul Yun,이응석,Choong-hyun Lee,Young-kyun Lim,Dae-Soon Lim 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.6
To reduce the processing cost and to polish high hardness substrates, a change from the currently used slurry process to the process using fixed abrasive grain is required. Therefore, studying the fixed abrasive tool to improve yield and process stability is important. In this study, a chemical vapor deposition (CVD) diamond pellet with an artificially controlled contact area was applied to replace the slurry polishing process. The CVD diamond pellets were prepared by depositing a microcrystalline diamond on silicon nitride ceramic substrates using a hot filament CVD technique and preparing a multi-layered pellet in which a nanocrystalline diamond (NCD) was deposited. The influences of the real contact area of CVD diamond on the surface roughness and material removal rate were studied using scanning electron microscopy, a stylus profilometer, atomic force microscopy, and Raman spectroscopy before and after polishing. In addition, the polishing effect of the sapphire wafer was analyzed and predicted by modeling the roughness and the real contact area of the diamond CVD pellet. To analyze the polishing characteristics according to changes in the area, the surface roughness of the NCD was varied from 65 to 115 nm, and the polishing was evaluated. The results showed that compared with the process using diamond slurry, the multilayer diamond pellet had a higher material removal rate and the same surface roughness and total thickness variation.
Effect of the Properties of Uniformly Patterned Micro-Diamond Pellets on Sapphire Grinding
Joong-Cheul Yun,Byung-young Wang,Eung-seok Lee,Choong-Hyun Lee,Young-kyun Lim,Dae-SoonLim,Han-Gyoung Cho 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.7
If nanoscale roughness of machined surfaces is to be achieved, a machining method using a ductile grinding mode is required. If this using a diamond tool is to be realized, uniform patterned micro-diamond pellets must be produced on the tool surface. In this study, uniform patterned micro-diamond pellets were fabricated by using Lithographie Galvanoformung Abformung (LIGA) technology combined with electroplating technology. The effect of the size of the patterned diamond pellet on sapphire wafer grinding was analyzed using a scanning electron microscope and a surface profiler after grinding. As a result, 12 uniformly patterned micro-diamond pellets were fabricated, and a sapphire substrate was ground to obtain a surface roughness (Ra) of 5 nm or less.
PC U형 단면을 사용한 포스트텐션된 넓은 보-기둥 외부접합부의 비탄성 거동
최윤철(Choi Yun-Cheul),임재형(Lim Jae-Hyung),권기혁(Kwon Ki-Hyuk),문정호(Moon Jeong-Ho),이리형(Lee Li-Hyung),김대중(Kim Dae-Joong) 대한건축학회 2004 大韓建築學會論文集 : 構造系 Vol.20 No.12
Post-tensioned precast concrete system(PPS) consists of U-shaped precast wide beams and concrete column The continuity of beam-column joint is provided with the topping concrete on the PC shell beam and post-tensioning The purpose of this paper is to evaluate the response of PPS exterior beam-column joint subjected to cyclic lateral loafing To this end, an experimental investigation was performed with three half-scale exterior connection subassemblages The design parameters were the beam width ratio to column width and the amount of beam reinforcement placed inside the column core The test results showed that specimen cracks were distributed well and plastic hinges spread toward midspan without any significant degradation of strength and ductility And the specimens sufficiently resist up to limiting daft ratio of 0.035 in accordance with the provisional by "Acceptance Criteria for Moment Frames Based on Structural Testing"
인공 슬관절 전치환술 이후에 반복적으로 발생하는 자발성 급성 혈관절증의 치료
유주형 ( Ju Hyung Yoo ),양희철 ( Hee Cheul Yang ),이윤태 ( Yun Tae Lee ),오현철 ( Hyun Chul Oh ),하중원 ( Joong Won Ha ),김진영 ( Jin Young Kim ) 대한슬관절학회 2008 대한슬관절학회지 Vol.20 No.2
A 67-year-old woman presented with six acute recurrent hemorrhagic episodes sixteen months after primary total knee arthroplasty. Femoral angiography demonstrated a prominent vascular blush on the superolateral side of the knee joint. The patient underwent therapeutic embolization of the superior lateral geniculate artery and a muscular branch from the popliteal artery. However, neglected embolization to the lateral inferior artery induced another episode of acute hemarthrosis. Finally, open arthrotomy allowed for identification and coagulation of the focus of acute bleeding in the lateral inferior geniculate artery.
윤중철,김우식,김형철,이종호,김주선,이해원,김병호,Yun, Joong-Cheul,Kim, Woo-Sik,Kim, Hyoungchul,Lee, Jong-Ho,Kim, Joosun,Lee, Hae-Weon,Kim, Byong-Ho 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.4
단전지의 성능을 혼합전도체인 LSCF 양극의 미세구조, 특히 전극반응에 필요한 표면적의 양과 연관되는 앙극의 기공률의 변화에 따라 평가하였다. 기공률이 서로 다른 양극을 제조하기 위해 미세한 양극분말과 조대한 양극분말의 혼합비를 달리하여 양극을 제조한 결과 양극의 기공률을 각각 14, 23, 27, $39\%$로 얻을 수 있었다. 양극 기공률이 서로 다른 4종류의 단전지에 대한 직류 전류차단법과 교류임피던스법을 이용한 전기화학적 평가 결과 전극에서의 분극은 양극의 기공률이 증가할수록 감소하는 결과를 얻었다. 이러한 분극특성은 양극의 기공률이 증가하며 전극반응에 필요한 활성면적이 증가했기 때문으로 추론되며 이러한 이유로 단전지의 성능 또한 양극의 기공률이 증가하면서 향상되는 것으로 나타났다. We analyzed the unit cell performance against the cathode porosity, which is supposed to be closely related with active sites for the cathode reaction. In order to fabricate the unit cells with different porosity in the cathode layer we changed the mixing ratio of fine and coarse LSCF cathode powders. The final porosity of each cathode layer was 14, 23, 27, $39\%$ respectively. According to the electrochemical analysis of unit cell performance via DC current interruption and AC impedance method, the electrodic polarization resistance was diminished as the cathode porosity increased. The decrease of polarization resistance was attributed due to the increase of active reaction sites and the enhancement of overall unit cell performance could be explained in the same line.
윤중철,이종호,김주선,이해원,김병호,Yun, Joong-Cheul,Lee, Jong-Ho,Kim, Joosun,Lee, Hae-Weon,Kim, Byong-Ho 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.4
혼합전도체 산화물, LSCF의 전극반응점 분포에 따른 분극현상을 관찰하기 위해 다공성 양극의 기공률을 변화시켜가며 분극특성을 관찰하였다. 전극의 기공률을 달리하기 위해 크기가 다른 두 종류의 LSCF 분말들을 혼합비를 달리하여 사용하였으며 GDC 전해질 기판에 스크린 인쇄법을 통해 전극을 구성한 후 반쪽전지 실험을 수행하였다. 제조된 후막전극의 기공률은 화상 분석법을 통해 측정하였으며 전극의 전체 비표면적을 유추하기 위해 2차원 이미지에서의 기공의 둘레 길이를 측정하였다. 교류 임피던스법을 이용해 분극 특성을 관찰한 결과 혼합전도체인 LSCF 양극에서의 전극반응은 i) 양극표면에서 이온화된 산소이온이 전해질과의 삼상계면까지 이동해 오는 단계, ii) 이동해온 산소이온이 양극으로부터 전해질로 전달되는 반응단계에 의해 제어됨을 알 수 있었다. 이러한 양극에서의 분극은 기공률의 증가에 따라 전극 반응에 필요한 활성 표면이 증가됨으로써 줄어드는 것을 알 수 있었다. In order to characterize the influence of the reaction-site density on the cathodic polarization property of LSCF, we chose the porosity of LSCF as a main controlling variable, which is supposed to be closely related with active sites for the cathode reaction. To control the porosity of cathodes, we changed the mixing ratio of fine and coarse LSCF powders. The porosity and pore perimeter of cathodes were quantitatively analyzed by image analysis. The electrochemical half cell test for the cathodic polarization was performed via 3-probe AC-impedance spectroscopy. According to the investigation, the reduction of oxygen at LSCF cathode was mainly controlled by following two rate determining steps; i) surface diffusion and/or ionic conduction of ionized oxygen through bulk LSCF phase, ii) charge transfer of oxygen ion at cathode/electrolyte interface. Moreover, the overall cathode polarization was diminished as the cathode porosity increased due to the increase of the active reaction sites in cathode layer.
Correlation 분석 기법을 적용한 요통 환자에 관한 레지스트리 데이터의 탐색적 분석
박창현,박무순,김형석,차윤엽,김순중,고연석,오민석,황의형,신병철,김창업,송윤경,Park, Chang-Hyun,Park, Mu-Sun,Kim, Hyung-Suk,Cha, Yun-Yeop,Kim, Soon-Joong,Ko, Youn-Suk,Oh, Min-Seok,Hwang, Eui-Hyoung,Shin, Byung-Cheul,Kim, Chang-Eop,Song 한방재활의학과학회 2017 한방재활의학과학회지 Vol.27 No.4
Objectives The aim of this study is to analyze the patients who have low back pain through registry. Methods We registered patients with low back pain who visited department of korean rehabilitation medicine in university hospitals on study. We collected data from 116 subjects consisted of 51 inpatients and 65 outpatients and ruled out 8 who didn't have pattern identification data at the point of inpatient or outpatient visit so we analyzed 108 in total. We used Pearson's product moment correlation to find correlationship among variables, and analyzed statistical data using Phyton scipy library stats package. Results We set general features, region of the pain, physical examination, ROM, questionnaire results, pattern identification as variables and draw a conclusion by analyzing these variables. Conclusions Registry aimed at low back pain patients was established in department of korean rehabilitation medicine of university hospitals and exploratory analysis based on data were made. Through the registry, we expect that more advanced studies will be performed; for example, executing research which verifies effectiveness and stability of korean medical treatment or developing tools to fill the gap between pattern identification and disease identification.
아플라톡신을 간회 투여한 랫드의 간에서 CYP450 1A1, p53의 발현과 DNA adduct의 형성
이범준,이숙진,김태명,김대중,남상윤,현상환,강종구,홍진태,김철규,윤영원,Lee, Beom Jun,Lee, Sook Jin,Kim, Tae Myoung,Kim, Dae Joong,Nam, Sang Yoon,Hyun, Sang Hwan,Kang, Jong Koo,Hong, Jin Tae,Kim, Cheul Kyu,Yun, Young Won 대한수의학회 2004 大韓獸醫學會誌 Vol.44 No.4
Aflatoxins are produced mainly by Aspergillus flavus and Aspergillus parasiticus that grow in improperly stored cereals. Aflatoxin B1 ($AFB_1$) is a potent hepatocarcinogen in a variety of experimental animals including human beings. In spite of a high attention to the hepatocarcinogenecity of $AFB_1$, the relative toxicity of aflatoxins ($AFB_2$ and $AFG_1$) is not fully clarified. Sprague-Dawley male rats were orally administered with $AFB_1$, $AFB_2$, and $AFG_1$ at the dose of 250 ${\mu}g/kg$ (additionally including a dose of $1250{\mu}g/kg $ for $AFB_1$) body weight. Animals were then killed at 12, 24 or 48 hrs following aflatoxin exposure. Subsequently the immunohistochemical examination of p53, cytochrome p450 1A1 (CYP450 1A1), and glutathione-S-transferase placental form (GST-P) were performed. The level of the 8-OxodG in the liver was determined. Expressions of CYP450 1A1 and p53 were high in the liver of rats through 48 hrs after treatment of $AFB_1$ at the single dose of $250{\mu}g/kg $. This pattern was more clear as increasing doses. The treatment of $AFB_2$ and $AFG_1$ did not affect the expression of CYP450 1A1 but it caused weak expression of p53. The activity of GST were not found in the liver of rats treated with aflatoxins. The formation of 8-OxodG by $AFB_1$ increased in a dose-dependent manner up to 24 hrs after a single treatment of $AFB_1$ thereafter decreased to the level of control. The treatment of $AFB_2$ and $AFG_1$ did not affect the levels of 8-OxodG in the liver of rats with increasing time. These results in the present study indicate that $AFB_1$ among aflatoxins with low comparable levels is the most toxic as determined by early biomarkers such as CYP450 1A1, p53, GST-P, and 8-OxodG.