DRAM 커패시터용 $Ta_2O_5$ 박막의 전기적 특성에 미치는 전극의존성

김영욱,권기원,하정민,강창석,선용빈,김영남,Kim, Yeong-Wook,Gwon, Gi-Won,Ha, Jeong-Min,Kang, Chang-Seog,Seon, Yong-Bin,Kim, Yeong-Nam 한국재료학회 1991 한국재료학회지 Vol.1 No.4

A new electrode material for $Ta_2O_5$ capacitor was developed to obtain both high dielectric constant and improved electrical properties for use in DRAM. High leakage current and low breakdown field of as-deposited $Ta_2O_5$ film on Si is due to the reduction of $Ta_2O_5$ by silicon at $Ta_2O_5$/electrode interface. $Dry-O_2$ anneal improves the electrical properties of $Ta_2O_5$ capacitor with Si electrode, but it thickens the interfacial oxide and lowers the dielectric constant, subsequently. $Ta_2O_5$ capacitor with TiN exectrode shows better electrical properties and higher dielectric constant than post heat treated $Ta_2O_5$ film on Si. No interfacial oxide layer at $Ta_2O_5$/TiN interface suggests that there\`s no Interaction between $Ta_2O_5$ and electrode. TiN is a adequate electrode material for $Ta_2O_5$ capacitor. $Ta_2O_5$ 박막은 실리콘산화막, 실리콘질화막 박막에 비해 유전율은 높으나 누설전류밀도가 높고, 절연파괴강도가 낮아 DRAM의 커패시터용 재료로서 실용화가 되지 못하고 있다. 본 연구에서는 LPCVD법으로 형성시킨 $300{\AA}$ 두께의 $Ta_2O_5$ 유전체박막에 대해 후속열처리 또는 전극재료를 변화시켜 열악한 전기적 특성의 원인을 규명하고자 하였다. 그 결과 다결정 실리콘 전극의 경우 성막상태의 $Ta_2O_5$ 박막은 전극에 의한 환원반응에 의해 전기적 특성이 열화됨을 알 수 있었고, 이를 TiN 전극의 사용으로 억제시킬 수 있었다. 다결정 실리콘 전극의 경우 성막상태의 $Ta_2O_5$ 유전체는 누설정류밀도가 $10^{-1}A/cm^2$, 절연파괴강도가 1.5MV/cm 정도였으며, $800^{\circ}C$에서 $O_2$열처리를 하면 전기적 특성은 개선되나, 유전율이 낮아진다 TiN 전극을 채용할 경우 누설전류밀도 $10^{-6}~10^{-7}A/cm^2$, 절연파괴강도 7~12MV/cm 로 ONO(Oxide-Nitride-Oxide) 박막과 비슷한 $Ta_2O_5$ 고유전막을 얻을 수 있었다.

Midazolam을 이용한 의식하진정법을 시행한 환자에서 나타난 선행성 및 후행성 기억상실

김영욱,금윤선,모동엽,이장렬,김현철,이상철,Kim, Yeong-Wook,Keum, Yoon-Seon,Mo, Dong-Yub,Lee, Jang-Yeol,Kim, Hyoun-Chull,Lee, Sang-Chul 대한치과마취과학회 2011 Journal of Dental Anesthesia and Pain Medicine Vol.11 No.2

Midazolam is known to produce sedation as well as amnesia. Many articles reported about anterograde amnesia, but it is rare that articles about retrograde amnesia. The 61-year-old female patient (64 kg, 154 cm, ASA physical status I) was administered 3.02 mg (0.047 mg/kg) of midazolam during 2 hours. The patient's Modified Observer's Assesment of Alertness/Sedation Scale was 4. The patient who had been consciously sedated with midazolam, exhibited profound amnesia, both anterograde and retrograde after implantation. The patient's memory restoration was begun after 6 hours.

상악동저 거상술을 동반한 임프란트 동시 식립의 예지성 평가

김영욱(Yeong-Wook Kim),금윤선(Yoon-Seon Keum),손효정(Hyo-Jeong Son),이장렬(Jang-Yeol Lee),김현철(Hyoun-Chull Kim),이상철(Sang-Chull Lee) 대한치과의사협회 2010 대한치과의사협회지 Vol.48 No.3

Purpose The aim of this study is to evaluate the survival rates and analyze the stability of lateral approach and trans-crestal approach for maxillary sinus floor elevation of simultaneous implant placement. Materials and method 407 patients who have been treated in LivingWell dental hospital between 2003 to 2009 were selected. Lateral window technique, osteotome technique and sinus drill technique were used for sinus floor elevation procedure. A total of 714 implants-MP-1 HA coated implant(Tapered Screw Vent™, Spline™, Zimmer, USA), FBR surfaced implant(Pitt-Easy™, Oraltronics, Germany)-were placed in grafted maxillary sinus simultaneously. The autogenous bone or a combination with the allograft or alloplast was grafted into sinus. Sinus floor elevation was combined with vertical/horizontal onlay bone grafts to reconstruct the defect of alveolar ridge. Results The average preoperative height of the maxillary alveolar bone was 5.78㎜(range: 0.4㎜~12.5㎜). 14 implants failed during the healing period(lateral approach: 4, trans-crestal approach: 10) and 3 implant failed after prosthetic loading(lateral approach: 2, trans-crestal approach: 1). The cumulative survival rate of implants after 6 years was 97.6%. Trans-crestal approach(97.4%) and lateral approach(97.9%) had similar survival rates. Conclusion The results indicate that the trans-crestal approach and lateral approach for maxillary sinus elevation is a acceptable method at atrophic maxillary posterior area.

의사를 대상으로한 비만양상과 그 관련요인에 관한 연구

김영실,박혜숙,조봉수,김영욱,고광욱,강수용,차애리,이철호,황인경,조병만,이수일,김돈균,Kim, Young-Sil,Park, Hye-Sook,Cho, Bong-Su,Kim, Yeong-Wook,Koh, Kwang-Wook,Kang, Soo-Yong,Cha, Ae-Ri,Yi, Cheol-Ho,Hwang, In-Kyung,Cho, Byung-Mann,Lee, S 대한예방의학회 1997 예방의학회지 Vol.30 No.4

The author surveyed overall obesity indicies and factors concerned with obesity such as dietary intake, physical activity, stress and life style with the subject of doctors. The number of subjects was total 508 with 396 men and 112 women. They were subgrouped into surgical part, medical part and service and basic part by speciality. And also subgrouped into intern and resident, pay doctor, and practitioner by working type. The results were as follows. 1) Obesity indices: BMI of total doctor was $23.1{\pm}2.8$, and WHR was $0.87{\pm}0.08$ and overweight prevalence(BMI>25.0) was 23.6%. It was within normal limit but slightly over the Korean standard. The degree of obesity indices of subgroups by speciality was 'surgical part > medical part > service and basic part', and by working type was 'practitioner > pay doctor > intern and resident'. 2) Dietary intake and Physical activity: Average dietary intake was $2148{\pm}451kcal/day$. The degree of dietary intake by speciality was 'surgical part > medical part > service and basic part'. By working type it was 'practitioner > pay doctor > intern and resident'. Average physical activity was $29{\pm}5$ METs/day. The degree of physical activity also showed similiar pattern. But there was no significant difference among each groups. 3) Comparision between over-weight and non-over-weight group: The items that showed significant difference between two groups were dietary intake, skip breakfast, regular exercise, smoking, heavy drinking, chronic disease etc.

항공 응용 분야 : 마이크로프로세서를 이용한 영구자석형 동기전동기(PMSM) 제동력 확보 제어기 설계에 관한 연구

나승권 ( Seung Kwon Na ),김영욱 ( Yeong Wook Kim ),최기호 ( Gi Ho Choi ),황락훈 ( Lark Hoon Hwang ) 한국항행학회 2013 韓國航行學會論文誌 Vol.17 No.5

본 연구에서는 영구 자석형 동기전동기(PMSM)를 축소형의 견인시스템으로 각 전동기를 개별로 제어하는 1C1M방식으로 구축하였다. 전동기를 제동할 때 발생한 회생전력은 모두 활용하고 있으며 전기제동의 사용영역 확대에 발생한 회생전력을 모두 흡수할 수 있는 능력을 가진 가선이라고 가정한다. 영구 자석형 동기전동기 (PMSM)의 제동력 확보를 위해 벡터제어 방법과 제어기와 속도 센서를 마미크로프로세서에 제어기를 적용 하였고, 전동기 에너지의 효율적 이용 등 회생 제동에 의한 제동력 확보와 전기 제동으로 정지하는 알고리즘을 적 용하여 전동기 관성부하에 대한 시뮬레이션 및 실험결과를 제안하였다. 1C1M방식으로 구축하였다. 전동기를 제동할 때 발생한 회생전력은 모두 활용하고 있으며 전기제동의 사용영역 확대에 발생한 회생전력을 모두 흡수할 수 있는 능력을 가진 가선이라고 가정한다. 영구 자석형 동기전동기 (PMSM)의 제동력 확보를 위해 벡터제어 방법과 제어기와 속도 센서를 마미크로프로세서에 제어기를 적용 하였고, 전동기 에너지의 효율적 이용 등 회생 제동에 의한 제동력 확보와 전기 제동으로 정지하는 알고리즘을 적 용하여 전동기 관성부하에 대한 시뮬레이션 및 실험결과를 제안하였다. In this paper, A tow system of miniature establishes each motor to individual 1C1M methods to control for a permanent magnet synchronous motors (PMSM) is constructed. You assume that is wiring having had the ability that can all absorb regenerative power which occurred when permanent magnet synchronous motors (PMSM) brake is all used to it, and to occur about agreement use scope expansion my electricity. To regenerative braking power securities of a PMSM and to stop of the bronzes my a control security, and that the electricity as you apply to vector control method and an speed sensor of controller to microprocessor, And you studied to speed, motor electricity energy control method to the algorithm and you brake a revival by regenerative braking power securities of a permanent magnet synchronous motors. It is proposed that motor control method to the algorithm you brake a revival by electricity braking power securities, you do to simulations regarding a momentum load and experiment.

하이브리드형 압전 변압기의 고주파 승압 초퍼를 이용한 적응제어기법 유도전동기 속도 센서리스 벡터제어에 관한 연구

황락훈 ( Lark Hoon Hwang ),나승권 ( Seung Kwon Na ),김영욱 ( Yeong Wook Kim ),최성식 ( Song Shik Choi ) 한국항행학회 2013 韓國航行學會論文誌 Vol.17 No.3

본 논문에서는 최근, 압전 변압기 기술의 급속한 발전을 이용하므로 자계의 잡음이 없고, 크기가 소형화되며 고효율과 고 전력 밀도, 누설자속이 없어 노이즈 발생이 없고, 공진주파수만을 이용하므로 출력파형이 정현파에 가까워 고조파 잡음이 없는 점을 이용하여 전기적인 등가회로를 적용하여 DC-DC 컨버터를 구현 하였다. 유도전동기 회전자 속도 개념에 자속 기준 모델 적용 시스템(FMRAS)을 적용하였다. 유도전동기의 벡터제어는 회전자 속도 정의의 추정값을 이용하여 실행 할 수 있고, 부가된 변화되는 모델로 회전자 목표값 계산을 수행 할 수 있다. 이 시스템은 PWM 공간 전압기법과 DC-DC 컨버터를 이용하여 벡터전류제어와 속도제어를 위한 PI제어기로 구성되어 있다. 제어를 위한 실행과 높은 속도계산을 디지털 신호 원칩 마이크로프로세서에 의해 수행 되었고, 시뮬레이션과 실험을 통해서 다양한 제어 방법의 타당성을 제시 하였다. In this paper, recently, it is described to the piezoelectric transformer technology develops, because it was have to favorable characteristics such as electromagnetic-noise free, compact size, higher efficiency, and superior power density, flux linkage, noiseless, etc. its resonance frequency was used to output waveform of a sine wave. A rotor speed identification method of induction motor based on the theory of flux model reference adaptive system(FMRAS). The estimator execute the rotor speed identification so that the vector control of the induction motor may be achieved. The improved auxiliary variable of the model are introduced to perform accurate rotor speed estimation. The control system is composed of the PI controller for speed control and the current controller using space voltage vector PWM techniuqe and DC-DC converter. High speed calculation and processing for vector control is carried out by digital signal one chip microprocessor. Validity of the proposed control method is verified through simulation and experimental results.

혈액투석 환자의 동정맥루 수술 시에 수술부위의 혈관구경과 조기 폐쇄와의 상관관계

김영욱,김남일,김승남,윤선애,문인성,박장상,고용복,유승진,정용호 대한혈관외과학회 1998 Vascular Specialist International Vol.14 No.2

Early obstruction of arteriovenous fistula (AVF) is one of the most frequent problems associated with vascular access in patients with chronic renal failure undergoing hemodialysis. It is concluded that old age and diabetes mellitus are risk factors for obstruction of AVF in hemodialysis patients. In order to evaluate the relation between radial artery, cephalic vein diameter and early obstruction of radiocephalic AVF within 3 months after operation, we measured radial artery, cephalic vein diameter and anastomosis length under the microscope during operation in 67 patients undergoing radiocephalic arteriovenous fistula. The mean age of patients was 50±13 (25∼74) years old and male to female ratio was 0.8. Diabetic nephropathy was most common underlying renal disease. The incidence of early obstruction of AVF within 3 months after operation was 14.9% (10 patients). Radial artery diameter of successful group was statistically larger than that of failed group (2.77±0.70 mm vs 2.08±0.35 mm, p <0.001). But there was no difference in cephalic vein diameter (1.93±0.70 mm vs 1.64±0.40 mm, p=0.199) and in anastomosis length (1.66±0.23 cm vs 1.67±0.17 cm, p=0.913) between two groups. There was no statistical difference in age, sex, overweight, time of puncture after operation, blood pressure between successful and failed group. The incidence of diabetes mellitus of failed group tended to be higher than that of successful group, but there was no statistical difference between two groups (60.0% vs 40.3%, p=0.247). There was no statistical difference in all laboratory findings including hemoglobin, hematocrit, platelet, serum albumin, and total cholesterol between two groups. In conclusion, radial artery diameter was associated with the early obstruction of radiocephalic AVF, while cephalic vein was unrelated to early obstruction. If radial artery is small in patients undergoing radiocephalic AVF, AVF at elbow or synthetic graft should be considered.