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초음파 기구가 수종의 치과용 시멘트의 결합강도에 미치는 영향에 관한 연구
김원상,임주환,조인호,Kim, Won-Sang,Lim, Ju-Hwan,Cho, In-Ho 대한치과보철학회 1997 대한치과보철학회지 Vol.35 No.3
Ultrasonic instruments transfer electrical energy to mechanical energy resulting in vibration used for various dental treatments. If we could know the effect of ultrasonic instruments on the dental cements within the cast crown, we could take care when conducting periodontal surgery and when using the ultrasonic instrument to remove cast crown, it would be much more convenient. The purpose of this study was to compare the bond strength of several dental cements according to ultrasonic instrumentation time. In this study 4 types of cements were used to cement the specimens. they were treated with ultrasonic instrumentation for 0-5 minutes and the change in bond strength were statistically compared. The results were as followed. 1. The tensile bond strength of zinc phosphate cement decreased according to the increase in time of ultrasonic instrument and showed significant difference between 0 minutes and the others and between 1 minute and 2,3,4,5 minutes (p<0.05). 2. The tensile bond strength of polycarboxylate cement decreased according to the increase in time of ultrasonic instrument and showed significant difference between 5 minutes and the others and between 4 minutes and 0 minutes (p<0.05). 3. The tensile bond strength of zinc phosphate cement decreased according to the increase in time of ultrasonic instrument and showed significant difference between 5 minutes and the others (p<0.05). 4. The tensile strength of resin cements showed no statistically differences according to the ultrasonic instrumentation time. In conclusion, it is considered that zinc phosphate cements is most affected by ultrasonic instrumentations and resin cement is the least affected. When using ultrasonic instruments the result avove should be used as an index.
양극산화 처리한 임플랜트의 표면 특성 및 골유착 안정성에 관한 연구
김원상,조인호,Kim, Won-Sang,Cho, In-Ho 대한치과보철학회 2006 대한치과보철학회지 Vol.44 No.5
Purpose : This experiment examined the effects of anodization on commercially pure titanium implant fixtures. Material & methods : The implant fixtures were anodized at three different voltage levels, producing three different levels of oxidation on the surface of the fixure. Implant were divided into four groups according to the level of oxidation. Group 1 consist of the control group of machined surface implants, Group 2 implants were treated by anodizing to 100 voltage, Group 3 implants were treated by anodizing oxidation to 200 voltage Group 4 implants were treated by anodizing oxidation to 350 voltage. Surface morphology was observed by Scanning Electron Microscope(SEM) and the surface roughness was measured using NanoScan $E-1000^{\circledR}$. Implantation of the fixtures were performed using New Zealand white rabbits. $Periotest^{\circledR}$ value(PTV) resonance frequency analysis(RFA), and removal torque were measured in 0, 2, 4, 8, 12 weeks after implantation. Results : The results of the study were as follows: 1. Values for the measured surface roughness indicate statistically significant differences in Ra, Rq, and Rt values among group 1, 2, 3, and 4 at the top portion of the thread,(p<0.05) while values at the base of the threads indicated no significant difference in these values. 2. A direct correlation between the firming voltage, and surface roughness and irregularities were observed using scanning electron microscope. 3. No statistically significant differences were found between test groups regarding $Periotest^{\circledR}$ values. 4. Analysis of the data produced by RFA, significant differences were found between group 1 and group 4 at 12 weeks after implantation.(p<0.05) Conclusions : In conclusion, no significant differences could be found among test groups up to a certain level of forming voltage threshold, beyond this firming voltage threshold, statistically significant differences occurred as the surface area of the oxide layer increased with the increase in surface porosity, resulting in enhanced bone response and osseointegration.
신재생에너지 도입의 정책목표와 법제적 적합성 연구 -수송용 바이오디젤 정책을 중심으로-
김원상 ( Won Sang Kim ),이재승 ( Jae Seung Lee ) 한국환경법학회 2015 環境法 硏究 Vol.37 No.1
본 연구는 에너지 관련 법제에 나타난 신재생에너지 도입목적에 비추어 바이오디젤 도입의 정책목표와 법제적 적합성을 분석한다. 국내 에너지법은 상위법으로부터 하위법에 이르기까지 신재생에너지의 도입의 목적으로서 에너지안보 개념과 환경개념을 명시하고 있으며, 바이오디젤의 도입과 관련한 정책은 이러한 에너지법이 추구하는 목적을 달성하기 위한 법제적 장치를 마련하고자 한다. 국내 에너지법제상의 신재생에너지의 도입목적으로서 에너지안보는 에너지 자립과 에너지의 안정적인 공급을, 환경은 환경친화적 에너지수급과 기후변화 대응을 위한 온실가스 감축을 각각 포함한다. 그러나 각 세분화된 정책목표의 실효성은 국내 바이오디젤 도입 과정을 살펴보았을 때 충분히 검증되지 않는다. 국내 시장에서 바이오디젤은 생산 원료의 절대량을 해외에 의존하고 있으며 기존 화석연료와 비교하여 가격경쟁력도 부족할 뿐 아니라, 수송용으로 소비되는 경유 중 2% 내외의작은 부분을 대체하고 있다. 환경적인 측면에서도 바이오디젤이 가지고 있는 친환경성을 증명할 사회적 인프라와 인증체계가 충분히 갖추어져있지 않다. 따라서 바이오디젤 정책은 에너지법이 신재생에너지의 도입을 통하여 달성하고자 하는 정책적 목표의 실효성을 보장하기 위한 법제적 장치의 보완이 필요하다. This study analyzes the suitability between policy objectives and legal framework of renewable energy in Korea, with the case of biodiesel policy. A series of energy-related laws stipulate the objective of renewable energy in terms of energy security and environment enhancement. Renewable energy should contribute to energy security by enhancing energy independence and stabilizing energy supply. The objective of environment enhancement include the provision of environment-friendly energy resources and the mitigation of greenhouse gases to deal with climate change. However, the introduction of biodiesel as renewable energy shows insufficient match between these policy objectives and related legal frameworks. Biodiesel production still relies heavily on imported primary resources and price competitiveness vis-a-vis fossil fuels is weak. Policy infrastructure and certification measures to prove environmental benefit of biodiesel were not yet established. Policy measures on biodiesel needs to strengthen the suitability between policy objectives and related legal mechanisms.
이중여자 유도형 풍력발전기의 전력제어를 위한 스위칭 이득기반의 선형궤환제어기법
김원상(Won-Sang Kim),심경훈(Gyung-Hun Sim),주성탁(Sung-Tak Jou),김서형(Seo-Hyoung Kim),이교범(Kyo-Beum Lee) 전력전자학회 2008 전력전자학술대회 논문집 Vol.- No.-
본 논문은 이중여자 유도형(DFIG) 풍력발전 시스템에서 유효전력과 무효전력을 직접적으로 제어하기 위해 가변구조제어의 일종인 스위칭 이득기반의 선형궤환(LFSG)제어기법을 제시한다. 개조된 직접전력제어기법 (DPC)과 공간벡터변조방식(SVM)은 제안하는 제어기법을 실현하기 위해 이용된다. 개조된 직접전력제어원리를 이용해서 설계된 LFSG제어기법은 널리 사용되고 있는 자속기준제어기법(FOC)에 비해서 간단한 제어구조로 강인성과 빠른 응답특성을 보인다. 시뮬레이션결과는 제안하는 제어전략의 타당성과 강인성을 확인해준다.
김원상(Won-Sang Kim),이종혁(Jong-Hyuk Lee),박제원(Jea-Won Park),최재현(Jae-Hyun Choi) 한국정보기술학회 2014 한국정보기술학회논문지 Vol.12 No.10
With development of SNS, users communicate with each other and share information online. Especially, field of politics that is sensitive to public sentiment grasps flow of the public using data with various method. SO-PMI, one of the popular techniques, sometimes shows a low precision because this method only computes positive words and negative words regardless of subject. So, this paper suggests opinion mining applied distance between subject and opinion word about election that would be begin on June, 2014. First, this process collects tweets about candidates for mayor of Seoul, Incheon and governor of Gyeonggi Province using Twitter api. After that, classify collected tweets as mach1.0, part of speech using morphological analyzer and it deducts result through suggested algorithm in this paper. The result data of experiment makes correspond approximately real data. Moreover, F-Score of this techniques performance has improved by 16% and 15% of positive/negative ratio and previous study.
Matrix Converter로 구동되는 유도전동기 구동장치를 위한 전력이론을 이용한 간단한 센서리스 기법
이교범(Kyo-Beum Lee),김원상(Won-Sang Kim) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
본 논문은 전동기의 일정한 공극자속과 전동기에 유입되는 무효전력을 이용한 매트릭스 컨버터 구동장치의 새롭고 간단한 센서리스 기법을 제안한다. 저속의 센서리스 성능 향상을 위해 정류지연, 스위칭장치들의 턴-온, 턴-오프시간 그리고 스위칭장치의 온-상태에서 전압강하와 같은 매트릭스 컨버터의 비선형성을 PQR 전력변환을 이용하여 모델링하고 기준 전류제어기법을 이용하여 보상한다. 3 ㎾급의 매트릭스 컨버터 구동시스템에 적용하여 제안된 센서리스 기법의 타당성을 검증한다.