Ta₂O_(5) 게이트 pH-ISFET의 제조 및 그 동작특성

권대혁,김명규,이광만,손병기 경북대학교 센서기술연구소 1991 센서技術學術大會論文集 Vol.2 No.1

To improve sensing characteristics of the pH-ISFET using LPCVD-grown Si_(3)N_(4), Ta_(2)O_(5) thin film depositied by RF reactive sputtering was used for hydrogen ion sensing gate and investigated sensing characteristics at various annealing temperatures. The XRD pattern showed that the crystal structure of the Ta20s thin film was amorphous when the annealing temperature was less than 500℃, δ-Ta_(2)O_(5) poly-crystal at MC Ta_(2)O_(5) gate pH-ISFET annealed at 400℃, O_(2) ambient for 1hour, the AES and RBS spectrum showed good stoichiometry (O/Ta=2.5). And its sensing characteristics showed good linearity and high sensitivity(57~59MV/pH) in the wide pH range(pH 2~12), and excellent long-term stability (0.03~0.05 pH/day). It can be concluded from these results that the sensing characteristics of Ta_(2)O_(5) gate pH-ISFET is more excellent than Si_(3)N_(4) gate pH-ISFET.

하수슬러지의 건설재로의 이용 타당성에 관한 연구

권재혁,박병수 三陟大學校 1999 論文集 Vol.32 No.2

Feasibility of using the mixture of a wastewater sludge and additive as liner and the cover materials in disposal landfill. Granite weathered soil flyash, produced as a by-produced as a by-product in the power plant, were used as the primary additives to improve geotechnical engineering properties of sludge. For secondary additives, bentonite and cement were mixed with sludge to decrease the permeability and to increase the shear strength, irrespectively. Various kinds of laboratory test, required to evaluate the design criteria for the liner and the cover materials, were carried out by changing the mixing ratio of sludge with the additives. Basic soil property tests of specific gravity, grain size distribution, the liquid and the plastic limits were performed to evaluate their properties and to analyze their effects on permeability, compaction of mixtures. Various test results with mixtures were assessed to evaluate whether their properties met the requirements as the liner and the cover materials in waste disposal landfill.

FET형 반도체센서 및 시스템 개발

손병기,조진호,최평,박이순,서화일,권대혁,고광락 경북대학교 센서기술연구소 1996 연차보고서 Vol.1996 No.-

기존의 센서들의 난점을 극복할 수 있는 새로운 형태의 FET형 전해질(electrolyte :H^+, K^+, Ca^2+, Na^+)센서소자 및 분석 시스템의 개발을 중점적으로 추진하였으며, FET형 포도당센서 및 압력센서의 개별 FET형 센서에 관한 연구도 병행하였다. FET형 전해질센서를 이용한 휴대용 전해질 측정기와 desktop형 4채널 전해질 분석기를 제작하였다. 또한 이 시스템을 소형화하기 위한 주문형 아날로그-디지탈 변환기 내장형 CMOS 프로세서를 설계하고 검증하였다. The main object of this research is to develope a new FET type electrolyte(H^+, K^+, Ca^2+, Na^+) sensors and analysis system which can overcome the problems of the conventional sensors. Parallel researches on FET type sensors such as glucose and pressure humidity are also in progress. A portable electrolyte meter and desktop 4-channel electrolyte analysis system is fabricated. A customized CMOS processor with built-in analog-to-digital converter is designed and verified.

FET형 마이크로센서 개발

손병기,박이순,서화일,권대혁,고광락 경북대학교 센서기술연구소 1996 연차보고서 Vol.1996 No.-

초음파 어레이를 이용한 이동 로봇의 장애물 회피에 관한 연구

김병남,권오상,김기호,이응혁 建陽大學校 1999 建陽論叢 Vol.- No.7

For mobile robot, the navigation effectiveness can be improved by providing autonomy, but this autonomy requires the mobile robot to detect unknown obstacles and avoid collisions while moving it toward the target. This paper presents an effective method for autonomous navigation of the mobile robot in structured environments. This method uses ultrasonic sensor array to detect obstacles and utilizes force relationship between the obstacles and target for avoiding collisions. Accuracy of sensory data produced by ultrasonic sensors is improved by employing error eliminating rapid ultrasonic firing (EERUF) technique. Navigation algorithm controlling both the velocity and steering simultaneously is developed, implemented to the mobile robot and tested on the floor filled with the cluttered obstacles. It is verified that from the results of the field tests the mobile robot can move at a maximum speed of 0.66 m/sec without any collisions.

수종 상아질 접착제의 결합강도와 중합률에 관한 연구

김병현,권혁춘 大韓齒科保存學會 1998 Restorative Dentistry & Endodontics Vol.23 No.1

The physical properties of polymer are greatly influenced by the extent to which resin cures. The presence of unreacted monomer can have a plasticizing effect on the polymer, thereby altering the physical and mechanical properties of dentin bonding agent(DBA). If the DBA does not polymerize sufficiently, it will leave a weak bonding layer and lead to lower bond strength. The purpose of this study was to evaluate te shear bond strengths(SBS) and the degree of conversion(DC) of 4 commercialy avilable dentin bonding systems which are composed of 2 multi-bottle systems [Scotchbond Multi-Purpose(SMP), AeliteBond(AB)] and 2 one-bottle systems [SingleBond(SB), One-Step(OS)]. For shear bond strength measurement, labial surfaces of freshly extracted bovine incisors were ground with #600 grit SiC paper to expose dentin. Four different groups of samples were formed, with 10 samples being made for each of the 4 commercial DBA in each group according to the curing sequences of DBA and overlayer thickness of composites:Group Ⅰ (standard cure and 1㎜ thick composites):The DBA was light cured and the composites of 1㎜ thickness was applied;Group Ⅱ (standard cure and 2㎜ thick composites):The DBA was light cured and the composites of 2㎜ thickness was applied;Group Ⅲ(simultaneous cure and 1㎜ thick composites):The DBA was not light-cured and simultaneously cured with composites of 1㎜ thickness;Group Ⅳ(simultaneous cure and 2㎜ thick composites):The DBA was not light-cured and simultaneously cured with composites of 2㎜ thickness. The SBS was measured immediately after the composites was bonded to the bovine dentin using an Instron machine. The DC of the DBA as examined in a thin film under simulated conditions of the experimental groups according to the curing sequences and overlayer thickness of composites in the SBS test. using a Fourier transform Infrared(FTIR) spectrometer. The following results were obtained from SBS tests and DC measurements 1. In SBS tests, the multi-bottle DBA(SMP, AB) had a generally higher bond strength values than the one bottle DBA(SB, OS). In DC measurements, the one bottle DBA(SB, OS) had a significantly higher DC than the multi-bottle DBA(SMP, AB). 2. In all DBAs except OS, there was no significant difference between the bond strength of group Ⅰ(standad cure and 1㎜ thick composites) and that of group Ⅲ(simultaneous cure and 1㎜ thick composites). SMP, SB in Group Ⅰ had a significantly higher DC than those in group Ⅲ, but AB, OS in group Ⅰ had a significantly lower DC than those in group Ⅲ 3. All DBAs in Goup Ⅱ(standard cure and 2㎜ thick composites) had significantly higher bond strength and DC than those in Group Ⅳ(simultaneous cure and 2㎜ thick composites). 4. In all DBAs, there was no significantly different SBS and DC between Group Ⅰ and Group Ⅱ, but all DBAs in Group Ⅲ had significantly higher SBS and DC than those in Group Ⅳ.

ZnO 압전박막을 이용한 FET형 압력센서의 특성

양규석,권대혁,남기홍,손병기 경북대학교 센서기술연구소 1994 센서技術學術大會論文集 Vol.5 No.1

A new FET type pressure sensor has been investigated to overcome the problems of the conventional silicon piezoresistive and capacitive pressure sensor. The PSFET( pressure sensitive field effect transistor) is a new FET type pressure sensor which the operation theory is combined with the field effect of MOSFET and the piezoelectric effect of piezoelectric thin films. This sensor can overcome the fabrication problems of conventional silicon pressure sensors and realize productivity, standardization, miniaturization, integration because the whole fab. process is compatible to the planar technology. A ZnO thin film as a piezoelectric material, 5000Å thick, was deposited on a FET gate by RF magnetron sputtering and the optimum deposition condition was 300℃ substrate temperature, 5mtorr working pressure, Ar ambient and 140watt RF power, respectively. And the device was annealed at 400℃, O_(2) ambient for 1 hour to obtain a better C-axis poling structure. The fabricated PSFET device showed piezoelectric voltage(40mV/kgf/cd) and sensitivity (21μA/kgf/cm^(2)) according to an applied pressure(1kgf/cm^(2)~4kgf/cm^(2)).

광섬유를 이용한 고감도 압력센서의 개발

김창원,권대혁,김진섭,이정희,손병기 경북대학교 센서기술연구소 1995 연차보고서 Vol.1995 No.-

KOH 수용액을 이용하여 실리콘 식각공정기술을 확립하였으며, 이를 이용하여 실리콘 기판 위에 스트레스 균형이 이루어진 150 ㎚-Si_3N_4/300 ㎚-SiO_2/150 ㎚-Si_3N_4 두께를 가지는 구조의 평탄한 3층 유전체 멤브레인을 제작하였다. 본 실험에서 사용되는 파장인 1.3 ㎛ 근방에서 다이아프레임의 광투과도는 약 50 %로 광반사막으로 사용이 불가능하였다. 따라서, 다이아프레임 뒷면에 약 1000 Å의 금을 증착하여 N/O/N/Au박막의 광투과도를 수 %정도로 감소시킴으로써, 센서의 광반사막으로 사용할 수 있었다. source fiber를 단일모드로 했을 때 다이아프레임의 크기에 따라 감도는 각각 0.52㎻/torr(3×3 ㎟), 0.65 ㎻/torr(4×4 ㎟), 0.77 ㎻/torr(5×5 ㎟)였다. 광손실을 최소화하기 위해 광전송용 다모드 광섬유를 사용하였을 때는, 2×2 ㎟의 다이아프레임의 크기에 대해 0∼800 torr의 넓은 측정범위에서 거의 선형적인 압력특성을 나타내었다. Using KOH solution, silicon etching technology has been established and stress-balanced flat 600 ㎚ thick triple dielectric membrane(150 ㎚-Si_3N_4/300 ㎚-SiO_2/150 ㎚-Si_3N_4) on silicon substrate has been fabricated. At the wavelength of the sensor light source near 1.3 ㎛, the optical transmittance of the diaphragm was about 50 %, it was impossible to be used as a reflecting film. To decrease to a few percents, the back-side of the diaphragm was deposited 1,000 Å thick gold layer, which is sufficient enough to be used as a light reflection layer of the sensor. When was used 8/126 ㎛ single-mode fiber, the respective sensitivities for diaphragm size were 0.52 ㎻/torr(3×3 ㎟), 0.65 ㎻/torr(4×4 ㎟), 0.77 ㎻/torr(5×5 ㎟). When was used 62/126 ㎛ multi-mode fiber for the light transmission to minimize optical loss, the pressure characteristics was showed almost linearly curve in a wide pressure range, 0 torr∼800 torr, for the 2×2 ㎟ diaphragm in dimensions.

GMS-5 가시영역 자료를 이용한 해면 일사량 추정

박경원,권병혁,김영섭 한국지리정보학회 2003 한국지리정보학회지 Vol.6 No.2

해상에서 1997년 1월부터 12월까지 맑은 날과 구름이 많은 대기상태에서 GMS-5에 장착된 VISSR(visible and infrared spin radiometer) 자료를 이용하여 5㎞×5㎞ 격자의 공간 분해능에서 태양복사를 추정하였다. 섬에 설치되어 있는 기상청의 pyranometer 자료로 추정 일사량을 검증하였다. 추정된 시간별 일사량의 RMSE(root mean square error)는 104W/㎡이고, 상관계수는 0.91이었다. 한반도 부근의 해상에서 조사된 시간별 태양복사의 최대값은 황해와 동해에서 6월에 나타나고, 남해에서는 8월에 나타나는데, 이는 6월에 저기압과 전선에 의한 기상 악화에 기인한다. Surface solar radiation over the sea is esitimated using the visible and infrared spin scan radiometer (VISSR) data onboard Geostationary Meteorological Satellite (GMS)-5 from January 1997 to December 1997 in clear and cloudy conditions. The hourly insolation is estimated with a spatial resolution of 5km×5km grid. The island pyranometer operated by the Japan Meteorological Agency(JMA) is used to validate the estimated insolation. The root mean square error of the hourly estimated insolation is 104W/㎡ with 0.91 of the correlation coefficient. In the variability of the hourly solar radiation investigated around the Korean Peninsula, the maximum value of solar radiation is hound in June at the Yellow Sea and the East Sea, while in August at the South Sea because of low pressure conditions and front in June.

요소 및 포도당 동시 측정용 ISFET다기능 바이오센서

김창수,권대혁,손병기 경북대학교 센서기술연구소 1990 센서技術學術大會論文集 Vol.1 No.1

A multi-biosensor for simultaneous detection of urea and glucose was fabricated by using ISFETs and Immobilized enzyme membrane and its performance characteristics were investigated. Detection of urea and glucose was possible in urea concentration range of 1~100mg/dl and glucose concentration range of 5~100mg/dl respectively. The ISFET multi-biosensor with strong advantages, very small size and fast response, showed high Potentials for in-situ measurements.