표면 도핑 기법을 사용한 SOI RESURF LDMOSFET의 항복전압 및 온-저항 특성 분석

김형우,김상철,방욱,강인호,김기현,김남균,Kim Hyoung-Woo,Kim Sang-Cheol,Bahng Wook,Kang In-Ho,Kim Kl-Hyun,Kim Nam-Kyun 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.1

In this paper, breakdown voltage and on-resistance characteristics of the surface doped SOI RESURF LDMOSFET were investigated as a function of surface doping depth. In order to verify the variation of characteristics, two-dimensional device simulation was carried out. Breakdown voltage of the proposed structure is varied from $73 {\~}138V$ while surface doping depth varied from $0.5{\~}2.0{\mu}m$. And on-resistance is decreased from $0.18{\~}0.143{\Omega}/cm^2$ while surface doping depth increased from $0.5 {\~}2.0{\mu}m$. Maximum breakdown voltage of the proposed structure is 138 V at $1.5{\mu}m$ depth of surface doping, yielding $22.1\%$ of improvement of breakdown voltage in comparison with that of the conventional SOI RESURF LDMOSFET with same epi-layer concentration. On-resistance characteristic is also improved about $21.7\%$.

박막증착시 티타늄 표면의 마손저항도와 세포독성에 관한 연구

김형우,김창회,김영수,Kim Hyung-Woo,Kim Chang-Whe,Kim Yung-Soo 대한치과보철학회 2001 대한치과보철학회지 Vol.39 No.1

Titanium is widely used in dentistry for its low density, high strength, fatigue resistance, corrosion resistance, and biocompatibility. But it has a tendency of surface damage under circumstance of friction and impact for its low hardness of the surface. Coating is one of methods fir increasing surface hardness. Its effect is to improve surface physical characteristics without change of titanium. Diamond-like carbon and titanium nitride are known for its high hardness of the surface. So that this study was aimed at the wear test and the cytotoxicity test of the commercially pure titanium and Ti-6Al-4V alloy which were deposited by diamond-like carbon film or titanium nitride film to acertain improvement of the surface hardness and the biocompatibility. A disk (25mm diameter, 2mm thickness) was made of commercially pure titanium and Ti-6Al-4V alloy and these substrates were deposited by diamond-like carbon film or titanium nitride film. Diamond-like carbon film was deposited by the method of radiofrequency plasma assisted chemical vapor deposition and titanium nitride film was deposited by the method of reactive arc ion plating. Then these substrates were tested about wear characteristics by the pin-on-disk type wear tester in which ruby ball was used as a wear causer under the load of 32N, The fracture cycles were measured by rotating the substrates until their films were fractured. The wear volume was measured after 150 cycles and 3,000 cycles using surface profiler. The cytotoxicity test was peformed by the method of the MTT assay. The results were as follows : 1. In the results of the wear volume test, commercially pure titanium and titanium alloy which were coated by diamond-like carbon film or titanium nitride aim had higher resistance against wear than the substrates which were not coated by any films (P<0.05). 2. In the results of the fracture cycle test and the wear volume test, diamond-like carbon film had higher resistance against wear than titanium nitride film (P<0.05). 3. In both coatings of diamond-like carbon aim and titanium nitride film, Ti-6Al-4V alloy had higher resistance against wear than commercially pure titanium (P<0.05) 4. In the results of the cytotoxicity test, diamond-like carbon film and titanium nitride film had little cytotoxicity as like commercially pure titanium or Ti-6Al-4V alloy (P>0.05).

총의치 환자의 만족도에 대한 연구

김형우,김정희,김영수,Kim, Hyung-Woo,Kim, Chang-Whe,Kim, Yung-Soo 대한치과보철학회 1995 대한치과보철학회지 Vol.33 No.3

A success of complete denture prosthesis can be determined by the satisfaction degree of the dentist and the patient. There are many factors influencing on the satisfaction of the complete denture patients. The purpose of this study is to analyze the correlation between the masticatory satisfaction and clinical evaluation, and the speech satisfaction and clinical evaluation in complete denture patients. 79 patients(total 119 complete dentures) were examined in this study who were treated in Seoul National University Dental Hospital. Through clinical evaluation, 2 examiners evaluated sex, age, edentulous period, the years of having used present complete denture, the number of the previous dentures, the state of the opposite arch, retention, stability, support, occlusion, vertical dimension of the complete denture and the condition of the residual alveolar ridge. Through questionnaires concerned with mastication and speech, examiners evaluate the satisfaction degree of the patients. This study led to the conclusion that : 1. The satisfaction degree of the mastication was lower in older patients(p<0.001) and in patients whose present complete denture period was shorter(p<0.05). The satisfaction degree of the mastication in male was higher than in female patients(p<0.01). 2. The satisfaction degree of the mastication was high when the retention of the complete denture was good(p<0.05), and when the condition of the residual alveolar ridge was good(p<0.05). 3. The satisfacion degree of the speech was high when the retention of the complete denture was good(p<0.01). 4. The satisfaction degree of the mastication was higher in patients with upper and lower complete denture than in patients with single complete denture whose oppsite arch was unilateral partial denture(p<0.05).

에피층 농도 변화에 따른 Multi-RESURF SOI LDMOSFET의 전기적 특성 분석

김형우,서길수,방욱,김기현,김남균,Kim, Hyoung-Woo,Seo, Kil-Soo,Bahng, Wook,Kim, Ki-Hyun,Kim, Nam-Kyun 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.9

In this paper, we analyzed the breakdown voltage and on-resistance of the multi-RESURF SOI LDMOSFET as a function of epi-layer concentration. P-/n-epi layer thickness and doping concentration of the proposed structure are varied from $2{\sim}5{\mu}m\;and\;1\{times}10^{15}/cm^{3}^{\sim}9\{times}10^{15}/cm^{3}$ to find optimum breakdown voltage and on-resistance of the proposed structure. The maximum breakdown voltage of the proposed structure is $224\;V\;at\;R_{on}=0.2{\Omega}-mon^{2}\;with\;P_{epi}=3\{times}10^{15}/cm^{3},\;N_{epi}=7\{times}10^{15}/cm^{3}\;and\;L_{epi}=10{\mu}m$. Characteristics of the device are verified by two-dimensional process simulator ATHENA and device simulator ATLAS.

디지털 비디오 광 디스크의 복제방지를 위한 후처리 암호화 기록 장치의 설계

김형우,주재훈,김진애,최중경,Kim, Hyeong-Woo,Joo, Jae-Hoon,Kim, Jin-Ae,Choi, Jung-Kyeng 한국정보통신학회 2010 한국정보통신학회논문지 Vol.14 No.6

This paper presents encrypted secret code recording system which can insert an unique manufacture ID code after complete disc process. First, we detect a memory block synchronizing signal which is SYNC. by using FPGA, then, design a recording pattern to write Multi Pulse. Finally, a method that any data is recorded in any place in any data area of optical disc by using a FPGA was proposed. Newly proposed method in this paper that any user records user data in protected data areas on digital video optical discs, can be very useful for effective software copy protection, and can be applicable to encrypted record on high density DVD in near future. 본 논문은 디지털 비디오 타이틀 제작 업체가 디스크 제작을 완료한 후 디스크 복제방지를 위한 목적으로 디스크의 일부영역에 타이틀 업체의 고유ID를 기록하는 후처리 암호화 기록장치에 대한 시스템을 제시한다. 그 방법으로서 FPGA를 이용하여 광디스크의 메모리블럭 동기화 신호인 SYNC.를 검출하고, 기록(Write)을 위한 다중펄스(Multi Pulse)를 발생시키는 기록 패턴을 설계한다. 그리고 사용자가 광 디스크의 데이터영역을 어느 곳이라도 자유자재로 기록이 가능하도록 FPGA로서 기록하는 방법을 제시하고 설계한다. 이러한 디지털 비디오 광 디스크의 비기록 데이터영역을 사용자 임의대로 기록하는 시스템을 개발함으로서 소프트웨어 복제 방지에 효과적으로 대응이 가능하며, 향후 고밀도 광 디스크의 암호화 기록에도 응용이 가능하다.

웹서비스와 스마트폰앱을 이용한 연안해양모델 예측자료의 시각화시스템 구현

김형우,구본호,우승범,이호상,이양원,Kim, Hyung-Woo,Koo, Bon-Ho,Woo, Seung-Buhm,Lee, Ho-Sang,Lee, Yang-Won 한국공간정보학회 2014 한국공간정보학회지 Vol.22 No.2

최근 해양레포츠 산업이 블루오션으로 떠오르고 있는데, 해양레포츠는 조류, 수온, 염도 등과 같은 다양한 환경조건에 영향을 받기 때문에 관측자료 뿐만 아니라 모델 예측자료도 매우 필요한 정보이다. 본 연구에서는 연안해양모델인 FVCOM(Finite Volume Coastal Ocean Model)에서 산출된 예측자료를 웹 및 스마트폰을 통해 제공하는 시각화시스템을 구현하였다. 이를 위하여 FVCOM 자료에 내삽과 샘플링 등의 전처리를 하여, 조위, 수온, 염도의 래스터 이미지와 조류(유속, 유향)의 벡터 데이터베이스를 구축하였고, 스프링 프레임워크(Spring Framework)를 활용하여 REST(Representational State Transfer) 기반의 API(Application Programming Interface)를 제공하는 웹서비스를 구축하였다. 또한 데이터베이스 자료를 데스크톱 및 이기종의 스마트폰에 탑재시킴으로써 크로스플랫폼(cross-platform) 시각화 환경을 실현하였다. Ocean leisure sports have recently emerged as one of so-called blue ocean industries. They are sensitive to diverse environmental conditions such as current, temperature, and salinity, which can increase needs of forecasting data as well as in-situ observations for the ocean. In this context, a Web-based geovisualization system for coastal information produced by model forecasts was implemented for use in supporting various ocean activities. First, FVCOM(Finite Volume Coastal Ocean Model) was selected as a forecasting model, and its data was preprocessed by a spatial interpolation and sampling library. The interpolated raster data for water surface elevation, temperature, and salinity were stored in image files, and the vector data for currents including speed and direction were imported into a distributed DBMS(Database Management System). Web services in REST(Representational State Transfer) API(Application Programming Interface) were composed using Spring Framework and integrated with desktop and mobile applications developed on the basis of hybrid structure, which can realize a cross-platform environment for geovisualization.

Chemical and Physical Properties and Blood Compatibility of Composites of Carrageenan and Gelatin

김형우,김승수(Sung Soo Kim),육순홍(Soon Hong Yuk),신병철(Byung Chunl Shin),이진호(Jin Ho Lee),박병기(Pyong Ki Pak),이해방(Hai Bang Lee) 한국고분자학회 1993 한국고분자학회 학술대회 연구논문 초록집 Vol.1993 No.10

신재생에너지 도입에 따른 시설재배의 경제성 분석 -목재팰릿, 지열과 경유의 비교분석을 중심으로-

김형우,윤성이,Kim, Hyung Woo,Yoon, Sung-Yee 한국유기농업학회 2014 韓國有機農業學會誌 Vol.22 No.2

We are now currently facing serious climate changes such as super typhoon, flood, intense heat, severe cold, super hurricane, drought, desertification, destruction of ecosystem, marine pollution, reduction of food production, destruction of tropical forests, exhaustion of water resources, climate refugees, etc. All of the above mainly derive from greenhouse gas exhaustion. Such harmful consequence might directly affect mankind's sustainable development. If we keep using resources that emits greenhouse gases, the global temperature will rise about $3.2^{\circ}C$ by year 2050. In case of $3^{\circ}C$ rise in temperature, it will result in abnormal climate which will bring about severe property damage. Moreover, 20~50% of the ecosystem will become extinct. As Korea's economy increasingly expands, so do our energy consumption rises. And because of the consequences that can be driven by increasing rate of resource use, not just Korea itself, but also the whole world should seriously concern about greenhouse gases. Although agricultural division only takes up about 3.2% of total greenhouse gas emission, the ministry of Agriculture, Food and Rural Affairs are taking voluntary actions to gradually reduce $CO_2$ and so does each and every related organizations. In order to reduce $CO_2$, introduction of new and renewable energy in farm house warming is crucial. In other words, implementing wood-pellet boiler and geothermal heat boiler can largly reduce $CO_2$ emission compared to diesel boiler. More importantly, not only wood-pellet and geothermal heat is pollution-free but they also have economic advantages some-what. In this thesis, the economic advantage and sustainablity will be introduced and proved through comparing practical analysis of surveyed farm house under structure employing wood-pellet boiler and geothermal heat boiler with Agriculture-Economic Statistic of 2012 who uses diesel boiler.

홍화(紅花), 천궁(川芎), 황기 약침액(藥鍼液)의 뇌교세포주 보호 효과

김형우,조수인,김일환,Kim, Hyung-Woo,Cho, Su-In,Kim, Il-Hwan 대한약침학회 2009 Journal of pharmacopuncture Vol.12 No.2

Objective : This study was carried out to investigate protective effects of Pharmacopuncture Solutions (PSs) made by Carthmi Flos (CF), Cnidii Rhizoma (CR) and Astragali Radix (AR) on C6 glioma cells Methods : We investigated the effects of PSs on proliferation rates and types of C6 cells, and also investigated the effects on LDH release. In addition, protective effects of PSs on oxidative stress induced by hydrogen peroxide and SOD-like activities were also investigated. Results : PSs made by CF, CR and AR did not show cytotoxicity in various concentrations. CF-PS and AR-PS elevated levels of proliferation rates significantly. Treatment with CF-PS lowered level of LDH release in C6 cells. In addition, CF-PS and CR-PS showed protective effects on cell death induced by hydrogen peroxide respectively. Finally, CF-PS group showed high level of SOD-like activity compared to that in CR-PS group. Conclusion : These results suggest that CF-PS can accelerate proliferation of neuroglial cells, and has protective action against oxidative stress, which was involved in anti-oxidative effects such as SODlike activities. In addition, CR has protective effects against oxidative stress, and AR can accelerate proliferation of neuroglial cells.

해저연약지반 시험집광기의 동적거동 해석

김형우,홍섭,최종수,여태경,Kim, Hyung-Woo,Hong, Sup,Choi, Jong-Su,Yeu, Tae-Yeong 한국해양학회 2008 바다 Vol.13 No.3

본 논문은 해저 연약지반 위를 주행하는 시험집광기의 동적거동 해석을 다루고 있다. 시험집광기는 단괴채집장치, 무한궤도, 단괴파쇄기, 샤시프레임, 전기 전자 시스템으로 구성되어 있다. 시험집광기의 공기 중 무게는 8,600 kg이며, 수중에서의 시험집광기의 평균접지압은 6.0 kPa이다. 상용해석 프로그램인 RecurDyn-LM과 Visual Fortran 90을 이용하여 시험집광기의 동적거동 해석 모델 및 유체저항력 모델을 구축하였다. 상용해석 프로그램(RecurDyn-LM)에서 제공되는 사용자 정의 서브루틴을 이용하여 연약지반역학 모델 및 유체저항력 모델을 구축하였으며, 이를 통하여 해저 시험집광기의 동적거동 해석을 수행하였다. 궤도속도, 지반조건, 항력계수 및 추가질량 계수의 변화에 따른 시험집광기의 동적응답을 분석하였다. We conducted a dynamic analysis of an underwater test collector, which operates on extremely soft soil of deep-seafloor. The underwater test collector consists of nodule pick-up device, vehicle tracks, nodule crusher, loading frame and electric-electronic system. The weight of underwater test collector is about 8600 kg. The average normal pressure, that the underwater test collector supports, is about 6.0 kPa. The dynamic analysis model of underwater test collector is developed using commercial software RecurDyn-LM and Visual Fortran 90. A terramechanics model of extremely soft soil is implemented to the software based on user-written subroutine and applied to the dynamic analysis of the underwater test collector model. The dynamic responses of test collector are studied with respect to track velocities, terrain conditions, and coefficients of added mass and drag.