슬관절 운동 평가를 위한 생체 임피던스 측정용 전도성 섬유센서 개발 및 평가

이병우,이충근,조하경,이명호,Lee, Byung-Woo,Lee, Chung-Keun,Cho, Ha-Kyung,Lee, Myoung-Ho 대한의용생체공학회 2011 의공학회지 Vol.32 No.1

This paper describes the development and assessment of conductive fabric sensor for evaluating knee movement using bio-impedance measurement method. The proposed strip-typed conductive fabric sensor is compared with a dot-typed Ag/AgCl electrode for evaluating validity under knee movement condition. Subjects are composed of ten males($26.6{\pm}2.591$) who have not had problems on their knee. The strip-typed conductive fabric sensor is analyzed by correlation and reliability between a dot-typed Ag/AgCl electrode and the strip-typed conductive fabric sensor. The difference of bio-impedance between a dot-typed Ag/AgCl electrode and the strip-typed conductive fabric sensor averages $7.067{\pm}13.987\;{\Omega}$ As the p-value is under 0.0001 in 99% of t-distribution, the strip-typed conductive fabric sensor is correlated with a dot-typed Ag/AgCl electrode by SPSS software. The strip-typed conductive fabric sensor has reliability when it is compared with a dot-typed Ag/AgCl electrode because most of bio-impedance values are in ${\pm}1.96$ standard deviation by Bland-Altman Analysis. As a result, the strip-typed conductive fabric sensor can be used for assessing knee movement through bio-impedance measurement method as a dot-typed Ag/AgCl electrode. Futhermore, the strip-typed conductive fabric sensor is available for wearable circumstances, applications and industries in the near future.

텅스텐(W) 원료에 따른 WO₃/TiO₂ SCR 촉매의 제조 및 촉매능

이병우,이진희,Lee, Byeong Woo,Lee, Jin Hee 한국결정성장학회 2014 韓國結晶成長學會誌 Vol.24 No.5

Anatase $TiO_2$에 각기 다른 텅스텐(W) 함유원료와 제조방법을 적용하여 $WO_3$ 촉매가 첨가된 SCR(selective catalytic reduction)용 분말을 합성하였으며, W 촉매 첨가가 합성분말의 상합성 및 SCR 촉매능에 미치는 영향에 대해 연구하였다. 촉매의 지지체인 $TiO_2$는 침전법으로 anatase 상으로 합성되었으며, anatase에서 고온상인 rutile로의 상전이 온도는 $1200^{\circ}C$였으나, $WO_3$를 10 wt% 첨가할 경우 이 상전이 온도는 $900^{\circ}C$로 낮아졌다. 건식으로 $WO_3$ 분말을 직접 첨가하여 $WO_3(10wt%)/TiO_2$를 제조한 경우 $350^{\circ}C$에서 $NO_X$ 제거 촉매능이 최고점에 이르나 온도증가에 따라 그 효율이 상당히 감소하였다. 암모늄-메타-텅스테이트를 습식으로 첨가하여 제조한 경우, 보다 고온인 $450^{\circ}C$에서 촉매능이 최고점에 이르렀으며 온도에 따른 효율감소 폭도 적었다. 이와 같은 경향은 $WO_3$와 $V_2O_5$를 동시 첨가하여 제조한 $V_2O_5(5wt%)-WO_3(10wt%)/TiO_2$ 촉매에서도 나타났다. 즉, 암모늄-메타-텅스테이트를 습식으로 첨가한 경우, $WO_3$를 직접 첨가한 경우에 비해 넓은 온도범위($300^{\circ}C{\sim}500^{\circ}C$)에 걸쳐 90 %에 이상의 우수한 $NO_X$ 변환효율을 보였다. An investigation of the influence of $WO_3$ addition with different precursors and preparation methods on the phase formation and selective catalytic reduction (SCR) efficiency of anatase-$TiO_2$ powders has been carried out. An anatase-$TiO_2$ synthesized by precipitation process was used as a catalyst support. For $WO_3(10wt%)/TiO_2$, the W loading to the $TiO_2$ support led to the lower in anatase to rutile transition temperature to ${\sim}900^{\circ}C$ from $1200^{\circ}C$ of the $TiO_2$ support alone. In the case of $WO_3(10wt%)/TiO_2$ SCR powders obtained from a wet process with ammonium meta-tungstate (AMT) precursor, the highest $NO_X$ conversion efficiency was achieved at $450^{\circ}C$ remaining high efficiency at $500^{\circ}C$, while the same composition prepared from a dry process with $WO_3$ addition showed the lowered efficiency with temperature after reaching the efficiency maximum at $350^{\circ}C$. The same tendency has been found that the $V_2O_5(5wt%)-WO_3(10wt%)/TiO_2$ SCR powders obtained from the wet process with AMT precursor has shown the superior $NO_X$ conversion efficiency over 90 % in a wider temperature range of $300{\sim}500^{\circ}C$.

지상 라이다를 활용한 트렌치 단층 단면 3차원 영상 생성과 웹 기반 대용량 점군 자료 가시화 플랫폼 활용 사례

이병우,김승섭,Lee, Byung Woo,Kim, Seung-Sep 대한자원환경지질학회 2021 자원환경지질 Vol.54 No.2

한반도 지진 재해 대비를 위해 지난 5년간 활성 단층 조사가 수행되어 왔다. 특히 피복 활성단층 조사는 항공 LiDAR 기반 지형 분석, 지표 지질 조사, 지구 물리 탐사 결과를 종합하여 피복된 단층면에 대한 트렌치 조사를 수반한다. 하지만 이러한 트렌치 조사에 의해 발견된 단층면은 한시적으로 연구된 후 복구되기 때문에 트렌치 단층면 현장에 대한 정보는 논문 및 보고서 등과 같은 정성 자료로 남게 된다. 이와 같은 한시적 지질 연구의 한계를 보완하기 위하여 이 연구에서는 지상 LiDAR를 활용하여 트렌치 단층면에 대한 3차원 점군 자료를 생성하고 디지털 공간상에서 트렌치 현장을 복원하였다. 지상 LiDAR 탐사는 양산 단층 지역에서 수행된 두 곳의 트렌치 조사 지점에서 수행되었으며, LiDAR 점군의 기본 속성값인 진폭과 반사도 이외에도 디지털 카메라를 활용하여 트렌치 단층면의 색상 정보도 측정하였다. 측정된 자료는 평균 0.003 m의 정합 오차를 가지는 3차원 점군 자료로 변환되어 트렌치 형상을 정교하게 복원하였다. 하지만 LiDAR 스캔 위치에 따라 점군의 진폭과 반사도 값이 변화되었으며, 햇빛 노출 정도에 따라서 트렌치 단면의 색상 정보가 다르게 형상화 되어 후처리 과정의 고도화가 필요함을 시사하였다. 이러한 점군 자료는 대용량 파일로 존재하고 점군 자료 가시화 방법 또한 제한적이기 때문에 3차원 점군 자료에 대한 연구자 간 공유가 어렵다. 이에 대한 대안으로 오픈소스 플랫폼인 Potree를 활용하여 트렌치 점군 자료를 웹 상에서 가시화하는 방법을 제안하였다. 이와 같이 우리는 시간적 그리고 공간적 제약 조건이 따르는 지질 현장 조사에서 지상 LiDAR 자료가 주요 지질 대상에 대한 재현성을 높일 수 있는 동시에 연구자 및 미래 후속 세대에 의해 손쉽게 활용될 수 있음을 보여주고자 한다. For disaster management and mitigation of earthquakes in Korea Peninsula, active fault investigation has been conducted for the past 5 years. In particular, investigation of sediment-covered active faults integrates geomorphological analysis on airborne LiDAR data, surface geological survey, and geophysical exploration, and unearths subsurface active faults by trench survey. However, the fault traces revealed by trench surveys are only available for investigation during a limited time and restored to the previous condition. Thus, the geological data describing the fault trench sites remain as the qualitative data in terms of research articles and reports. To extend the limitations due to temporal nature of geological studies, we utilized a terrestrial LiDAR to produce 3D point clouds for the fault trench sites and restored them in a digital space. The terrestrial LiDAR scanning was conducted at two trench sites located near the Yangsan Fault and acquired amplitude and reflectance from the surveyed area as well as color information by combining photogrammetry with the LiDAR system. The scanned data were merged to form the 3D point clouds having the average geometric error of 0.003 m, which exhibited the sufficient accuracy to restore the details of the surveyed trench sites. However, we found more post-processing on the scanned data would be necessary because the amplitudes and reflectances of the point clouds varied depending on the scan positions and the colors of the trench surfaces were captured differently depending on the light exposures available at the time. Such point clouds are pretty large in size and visualized through a limited set of softwares, which limits data sharing among researchers. As an alternative, we suggested Potree, an open-source web-based platform, to visualize the point clouds of the trench sites. In this study, as a result, we identified that terrestrial LiDAR data can be practical to increase reproducibility of geological field studies and easily accessible by researchers and students in Earth Sciences.

해양구조물용 silica 기반 내해수성 코팅제의 제조 및 응용

이병우,Lee, Byeong Woo 한국결정성장학회 2021 한국결정성장학회지 Vol.31 No.3

본 연구에서는 상온경화형 silica-based 코팅제의 제조 및 해양구조물에 적용하여 가혹한 해양환경에서 방식 및 방오 성능 발현을 위한 실용화 개발 연구를 수행하였다. 구조상 외부에 노출된 부분이 많은 해양(플랜트) 구조물은 강한 자외선, 극심한 온도차, 염수에 의한 부식 등 가혹한 해양환경에 고립되어 운용된다. 이러한 환경 하에서는 쉽게 열화 되고 파도 등 물리적 자극에도 쉽게 침식되는 유기계 페인트들은 그 역할을 제대로 할 수 없다. 해양구조물에 치밀한 세라믹 코팅을 형성시킬 경우 녹이 발생하지 않고 경도가 높아 시설물을 해수환경 하에서도 치밀하게 보호할 수 있다. 세라믹 코팅제의 경우 그 기능의 장점들로 인해 해양 구조물에서 그 용도와 적용범위는 크게 증진될 수 있을 것이다. 따라서 colloidal silica를 기반으로 실란계 커플링제, 경화제 및 세라믹 충진제로 구성된 silica-based 코팅제 조성개발과 해수중 방식 및 방오용 보호코팅제로의 응용에 대해 연구하였다. In this study, the development of the room temperature curable silica-based coating compositions for anticorrosive and antifouling performance in marine environments was carried out. The marine (plant) structures with many exposed parts are operated in harsh marine environments such as strong ultraviolet rays, extreme temperature differences and salt water corrosion. Organic paints that are easily degraded under these environments and easily eroded by physical stimuli such as waves can not play a role properly. Dense ceramic coatings on marine structures provide careful protections even in saltwater environments due to their high hardness and rust resistance. Therefore, in the case of ceramic coatings, their use and application range in marine structures can be greatly improved due to their functional advantages. In the present study, silica-based coating compositions based on colloidal silica with silane coupling agents, curing salts, and ceramic fillers were developed, and their applications as protective coatings for corrosion protection and fouling prevention in seawater were also studied.

Thermal properties of TiAlN and Ti-Al-O coated Inconel 617

이병우,Do Wan Kim,Jong Won Choi,Kwang Hyun Bang,Gun Hwan Lee,Hyun Cho 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6

TiAlN and Ti-Al-O thin films (~3 mm) were deposited on Inconel 617 by an arc-discharge and a RF sputtering method, respectively. The effect of the coatings on the thermal stability and wear properties of the Inconel alloy after heat treatment up to 1000 oC has been studied. The uncoated Inconel 617, heat treated at 1000 oC, showed a poor wear resistance and an inferior thermal stability due to the formation of thick corrosion scales in addition to the distinctive hill-shape crusts, which are both composed of Cr2O3 on the alloy surface. Ti-Al-O coated samples heat treated at 1000 oC also showed a poor wear resistance due to the considerable amount of Cr2O3 scale formation. It has been found that the TiAlN coating layer decomposed at 1000 oC and was oxidized into a TiO2-rich top-layer, followed by an Al2O3-rich layer between the top-layer and the alloy substrate. Since the dense protective oxide layers, which were oxidation products, prevented the formation of thick and brittle Cr2O3 scales (crusts) on the alloy surface, the TiAlN coated Inconel showed an enhanced thermal oxidation resistance and an increased wear resistance. TiAlN and Ti-Al-O thin films (~3 mm) were deposited on Inconel 617 by an arc-discharge and a RF sputtering method, respectively. The effect of the coatings on the thermal stability and wear properties of the Inconel alloy after heat treatment up to 1000 oC has been studied. The uncoated Inconel 617, heat treated at 1000 oC, showed a poor wear resistance and an inferior thermal stability due to the formation of thick corrosion scales in addition to the distinctive hill-shape crusts, which are both composed of Cr2O3 on the alloy surface. Ti-Al-O coated samples heat treated at 1000 oC also showed a poor wear resistance due to the considerable amount of Cr2O3 scale formation. It has been found that the TiAlN coating layer decomposed at 1000 oC and was oxidized into a TiO2-rich top-layer, followed by an Al2O3-rich layer between the top-layer and the alloy substrate. Since the dense protective oxide layers, which were oxidation products, prevented the formation of thick and brittle Cr2O3 scales (crusts) on the alloy surface, the TiAlN coated Inconel showed an enhanced thermal oxidation resistance and an increased wear resistance.

체외순환 개심술 환자의 혈청 및 뇨중 Amylase 변동에 관한 연구

이병우,김근호,Lee, Byeong-U,Kim, Geun-Ho 대한흉부심장혈관외과학회 1983 Journal of Chest Surgery (J Chest Surg) Vol.16 No.1

During the period of March 1981 to September 1982 a series of survey has been done on the value of amylase in blood and urine of 24 patients who went through the operation of heart surgery, for congenital and acquired heart diseases, with extracorporeal circulation at the Department of Thoracic _ Cardiovascular Surgery, School of Medicine, Hanyang University. In order to analyze the iteration and inter-relation of the value of amylase in blood and urine and the extra corporeal circulation time. The duration of extra-corporeal circulation time up to 60 minutes was classified as Group A while above 60 minutes was classified as Group B. The results are as follow; 1. 3 patients [23.07%] among 13 patients of Group A and 3 patients [27.27%] among 11 patients, showed increased amylase value after the surgery. 2. The average value in blood after operation was 120.3190.71 unit in Group A and 130.90113.15 unit in Group B. It was 11.59 units [9.63%] higher in Group A than in Group B. 3. 1 patient [7.7%] among 13 patients of Group A and 2 patients[18.18%] among 11 patients of Group B, the frequency of Group B was 10.48% higher. 4. The average Value of amylase in urine after the surgery was 111.9254.87 unit in Group A and 151.54111.17 unit in Group B. It was 39.62 unit [32.72%] higher in Group A than in Group B. 5. The longer the duration of extra corporeal circulation time showed the higher the amylase value in blood and urine after the operation. 6. Although the value of amylase in blood and urine was increased after operation, no patients Were found to have developed clinical pancreatitis.

합금원소가 FeCrX 합금표면에 형성된 산화물 박막의 결함에 미치는 영향

이병우,배차헌,김흥식 ( B . W . Lee,C . H . Bae,H . S . Kim ) 한국부식방식학회 1993 Corrosion Science and Technology Vol.22 No.1

MOD법에 의해 합성한 Willemite($Zn_2SiO_4$:Mn) 형광체의 발광 특성

이병우,이선길,조현,Lee, Byeong-Woo,Lee, Seon-Gil,Cho, Hyun 한국결정성장학회 2007 한국결정성장학회지 Vol.17 No.2

Metallo-organic decomposition(MOD)법으로 willemite 녹색 형광체를 합성하였고, 열처리 온도($800{\sim}1100^{\circ}C$) 및 Mn 활성제 농도($4{\sim}12 mol%$)에 따른 발광특성과 상합성에 대해 조사하였다. 254nm 여기원을 사용한 측정에서 형광체의 열처리 온도가 $800^{\circ}C$에서 $1000^{\circ}C$로 증가함에 따라 상대 발광 피크강도는 크게 증가하였고, XRD 분석 결과 $1000^{\circ}C$ 이상의 열처리 온도에서 전형적인 willemite 결정 구조를 보여 주었다. $1000^{\circ}C$의 온도로 열처리한 willemite 형광체는 Mn 활성제 농도가 8mol% 일 때 최대 발광 강도를 나타내었으며 10mol% 이상에서는 발광 강도가 급격히 저하되는 농도 ??칭 현상이 관찰되었다. SEM 분석 결과 형광체 입자 형상은 구형에 가까웠으며 $1000^{\circ}C$에서 소성된 형광체 입자 크기는 약 $0.4{\sim}0.5{\mu}m$ 이었다. Willemite green phosphor powders have been prepared by the metallo-organic decomposition (MOD) method, and the photoluminescence and phase formation were studied as a function of both the firing temperature ($800{\sim}1100^{\circ}C$) and the concentration of Mn activator ($4{\sim}12 mol%$). Under 254 nm excitation source, the emission intensity of the phosphors increased with increasing the firing temperature from 800 to $1000^{\circ}C$. From the XRD analysis, the powders heat-treated above $1000^{\circ}C$ showed willemite crystal structure. The maximum emission intensity was obtained far the phosphors heat-treated at $1000^{\circ}C$ with 8 mol% of Mn content. The concentration quenching was occurred when the Mn concentration exceeded 10 mol%. The phosphor particles showed spherical shapes with the average size of $0.4{\sim}0.5{\mu}m$ by the SEM morphology.

낙후지역 개발정책의 문제점과 개선방향에 관한 연구: 지역개발담당 공무원의 인식도를 중심으로

이병우,김남정,이명구,Lee, Byeong-Woo,Kim, Nam-Jung,Lee, Myoung-Gu 한국토지주택공사 토지주택연구원 2012 LHI journal of land, housing, and urban affairs Vol.3 No.4

1980년대 이후 본격적으로 추진된 낙후지역 개발정책은 수도권 집중을 완화하고 전 국토의 균형발전을 목표로 하였으나 지방을 종합적 체계적으로 육성하기보다는 중앙부처별로 소관업무를 분산하여 추진함으로써 지역특성이 반영되고 지역주민이 주도하는 수요자 맞춤형 개발이 이루어지지 못한 문제를 안고 있다. 이러한 문제인식 하에 본 연구는 현재 각 부처별로 시행되고 있는 주요 낙후지역 개발정책들에 대하여 지방자치단체 공무원들이 인식하는 다양한 문제점과 개선대책에 대한 조사를 통해 지역 현장에서 활용가능한 정책적 시사점을 도출하고자 하였다. 첫째, 각 중앙부처별로 분산적 개별적으로 추진되고 있는 낙후지역 개발정책의 통합 조정을 통한 지역개발사업의 계획 일관성 및 사업추진의 효율성을 제고할 필요가 있다. 둘째, 낙후지역 개발사업을 위한 재정 확충 및 운용시스템 개선 등 국고지원을 위한 기준의 합리적 설정이 필요하다. 셋째, 효율적인 지역개발사업 추진체계를 구축하여 사업간의 연계협력 강화와 맞춤형 사업 발굴 및 집행을 지원할 수 있는 제도적 보완이 필요하다. This paper examines the characteristics and status of the major development policies for under-developed region by ministries and studies how the awareness or perspective of public officials on such policies impact the policy environment. This paper aims to redefine the goal and strategy of regional development policy so that it can effectively contribute to enhancing the quality of life of residents and improving competitiveness of the region. The problems and improvement direction found out through a documentational and practical research on the development policy for underdeveloped region can be summarized as follows: Firstly, more streamlined and integrated policies which are currently fragmented being implemented by different ministries are needed to enhance the effectiveness of policy execution. Secondly, improvements on the process of securing government funding and operating systems are needed to guarantee the rational standard of providing state subvention, the expansion of comprehensive subsidy and the independence of policy execution. Thirdly, amendments on the policy measures are needed to support the development and execution of the customized projects, strengthen cooperation among those projects by establishing a system for effective regional development project.

TiCrN 코팅이 Inconel 617 합금의 고온안정성에 미치는 영향

이병우,박종천,김미루,구진희,김병익,조현,Lee, Byeong-Woo,Park, Jong-Cheon,Kim, Mi-Ru,Koo, Jin-Heui,Kim, Byeong-Ik,Cho, Hyun 한국결정성장학회 2011 한국결정성장학회지 Vol.21 No.6

TiCrN layers (Ti : Cr = 20 : 80 and 5 : 95 wt%) were deposited on Inconel 617 and the effect of TiCrN coating on the high temperature stability of Inconel 617 up to $1000^{\circ}C$ was examined. XRD analysis and microstructural observation showed that vigorous and inhomogenous Cr diffusion to the surface was suppressed by TiCrN layer compare to the uncoated Inconel 617. This led to a distinctive enhancement in thermal oxidation resistance of Inconel 617. 두 가지 조성의 TiCrN 코팅층(Ti : Cr = 20 : 80 및 5 : 95wt%)을 Inconel 617 합금 위에 증착하고, 1000oC까지의 온도영역에서 TiCrN 코팅이 Inconel 617 합금의 고온안정성에 미치는 영향을 조사하였다. XRD 분석과 미세구조 관찰을 통해 표면으로의 불균일한 Cr 확산이 TiCrN 층에 의해 억제되었음을 알 수 있었다. 그 결과 Inconel 617의 열산화 저항성이 현저하게 향상되었음을 확인하였다.