석탄회분의 융착형성 연구

이시훈,박주식,임영준,김형택 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.1

본 연구에서는 DTF를 이용하여 준역청탄인 Alaska탄의 회분과 deposit을 제조하고 조성을 분석하여 각각의 조성이 용융성에 미치는 영향을 고찰하였으며 ASTM 회분의 결과와 비교하였다. ASTM 회분은 alumina, silica, mullite, Ca-com-pound 등이 결정성으로 존재하는 반면 DTF 회분은 표면에 K, Fe, Ca 등이 농축된 구형의 drop이 만들어지는 것을 알 수 있었다. 또한 DTF 회분에는 mullite만이 결정성으로 존재하였다. Deposit은 용융후 고형화된 glass phase로 만들어 졌는데 Fe는 Fe^(3+) silicate로 전이되고 deposit하부에 Si가 농축되는 것으로부터 석탄 내의 무기물 조성 중에 용융을 지배하는 것은 Si인 것을 알 수 있었다. Alaska탄은 ASTM 회분분석결과로부터는 용융성이 강하게 예측되었으나 DTF에서 형성된 deposit 분석결과 표면에 부착강도를 낮게 하는 Ca가 농축되어 열전달면에서의 제거는 용이한 것으로 판단되었다. Ash and deposits were made using Alaska sub-bituminous coal in a drop tube furnace(DTF) and the effects of their compositions on fusion were compared with those of the ashes prepared from the ASTM aching procedure. It has been found that the ASTM ash includes alumina, silica, mullite, and Ca compounds as crystalline phases, whereas the DTF ash includes spherical drops with K, Fe, and Ca condensed on the surface. In a DTF ash, only mullite existed as crystalline phase. 'Che deposits existed as glass phases which were formed by solidification from melts, and Fe was transformed to Fe^(3+) silicate and Si was concentrated on the lower part of the deposit. This fact indicates that, among various inorganic elements in coal, Si controls the fusion. Although it was initially predicted that Alaska coal ash have strong slagging propensity based on the results of ASTM ash characterization, the results of analysis of the DTF deposits shows that the deposits can be easily removed from the heat transfer area because it is enriched with Ca which reduces the strength of its adhesion to the solid surface.

내시경적 조임근절개술후에 발생한 췌십이지장 가성동맥류 1예

박수영,김윤정,박진한,전현수,박시형,이영진,이은지,김지현 仁濟大學校 白病院 2010 仁濟醫學 Vol.31 No.-

We reported a case of pancreatic pseudoaneurysm, involving pancreaticoduodenal artery, developed after endoscopic retrograde cholangiopancreatography(ERCP) with endoscopic sphinterotomy. A 54 year old woman was transferred to our hospital due to sustained hematochezia and hypovolemia. A week before admission, she underwent ERCP with endoscopic sphinterotomy for acute cholangitis in local clinics. She developed abdominal pain and hematochezia at 12 hours after the procedures. A post procedure contrast enhanced computed tomography of abdomen demonstrated a pseudoaneurysm in inferior portion of pancreatic head. This was not present on the pre procedure contrast enhanced computed tomography of abdomen and was thought to arise from the pancreaticoduodenal artery as a complication of the pre sphincterotomy. She was brought to our emergency room in a state of hypovolemia. A upper endoscopy showed active bleeding from ampula of vater. An celiac angiography demonstrated pancreatic pseudoaneurysm involving inferior pancreaticoduodenal artery and selective coil embolization of was performed.

Complex Wavelet Transform 알고리즘의 CUDA 기반 병렬처리 고속화 연구

박시현(Si-Hyun Park1),김준식(Joon-Seek Kim)주효님(Hyonam Joo) 호서대학교 공업기술연구소 2013 공업기술연구 논문집 Vol.32 No.2

Wavelet transform 은 영상 압축, 3D 측정 등 여러 분야에 사용되고 있는 알고리즘이다. 본 논문에서는 이러한 Wavelet transform 중에 연산량이 많 고 ,시간이 오래 걸리는 Complex Wavelet Transform(CWT) 에 대하여 속도 개선을 위한 병렬처리 알고리즘을 제안 하고자 한다. 낮은 비용으로 대규모 병렬처리 환경 구축을 위해 CU DA 를 이용하여 Graphic Processing Unit(GPU) 보드상에서 고속화를 구현 하였다. 제안한 병렬처리 알고리즘의 실제 구현을 통해 Central Processing Unit(CPU) 보다 GPU 가 최대 약 90 배가량 수행 속도의 향상을 보였다. 또한 영상의 크기가 증가할수록 수행시간의 향상 폭이 커짐을 알 수 있었다. Wavelet transform is used in many areas o f image compression, 3D measurement, and etc In this paper, we proposed the fast parallel processing algorithm for Complex Wavelet Transform(CWT) which has many number o f computational amount. To implement the fast algorithm, we used the CU DA architecture on Graphical Processing U nit board that can construct a massively parallel processing environment in low price. In the real implementation, the proposed parallel processing algorithm shows the performance which is maximally faster about 90 times than the computational time on Central Processing Unit(CPU). Also, we obtained the result which the proposed method has more speedup performance according as image size is large.

지능형 자동차 주변 감시 시스템 설계 방안

장시웅(Si-woong Jang),박영식(Young-sik Park),성현용(Hyun-yong Sung),곽길봉(Gil-bong Kwak),김선남(Seon-nam Kim),김경진(Kyeoung-jin Kim) 한국정보기술학회 2009 Proceedings of KIIT Conference Vol.2009 No.-

본 연구는 차량 주변을 지능적으로 감시하는 자동차 주변 감시시스템에 관한 것으로, 자동차의 주행 및 주차 시 속도의 변화나 운전자의 요청에 의해 자동차 주변 지역에 관한 시야를 상황에 따라 달리하여 모니터링 함으로써 운전자가 안전한 주행 및 주차를 수행할 수 있게 하기 위한 것이다. 그러한 목적을 달성하기 위하여 본 연구에서는 차량의 주변부를 감시하기 위하여 차량의 외곽에 설치된 카메라의 각도가 지면으로부터 차량의 상부를 향하는 방향으로 변경될 수 있도록 제어하는 제어부, 카메라의 영상을 입력받아 차량주변의 영상을 생성하는 영상처리모듈, 영상처리모듈에서 생성된 영상을 출력하는 디스플레이를 포함하는 것을 특징으로 하는 지능형 자동차 주변 감시시스템을 제안한다. This study is on a vehicle surroundings monitoring system, which enables a driver to travel and park safely by monitoring vehicle surroundings, depending on the speed of vehicle and driver's control when traveling and parking. To achieve the aforementioned purpose, we propose an intelligent vehicle surroundings monitoring system, which consists of a control part, an image processing module and display module. Hence, the control module controls angle of camera to turn upward from the bottom to monitor vehicle surroundings. The image processing module merges the received images from cameras with the original vehicle image to display the vehicle’s surroundings in real time as if looking down from the sky.

A Study on Improvement and Degradation of Si/SiO₂ Interface Property for Gate Oxide with TiN Metal Gate

Lee, Byung-Hyun,Kim, Yong-Il,Kim, Bong-Soo,Woo, Dong-Soo,Park, Yong-Jik,Park, Dong-Gun,Lee, Si-Hyung,Rho, Yong-Han The Korean Institute of Electrical and Electronic 2008 Transactions on Electrical and Electronic Material Vol.9 No.1

In this study, we investigated effects of hydrogen annealing (HA) and plasma nitridation (PN) applied in order to improve $Si/SiO_2$ interface characteristics of TiN metal gate. In result, HA and PN showed a positive effect decreasing number of interface state $(N_{it})$ respectively. After FN stress for verifying reliability, however, we identified rapid increase of $N_{it}$ for TiN gate with HA, which is attributed to hydrogen related to a change of $Si/SiO_2$ interface characteristic. In contrast to HA, PN showed an improved Nit and gate oxide leakage characteristic due to several possible effects, such as blocking of Chlorine (Cl) diffusion and prevention of thermal reaction between TiN and $SiO_2$.

흰쥐에서 심정지후 뇌의 허혈-재관류 손상과 Tumor Necrosis Factor-α의 상관관계

최승필,박규남,박승현,박상현,정시경,김세경 대한응급의학회 1999 대한응급의학회지 Vol.10 No.4

Background : Tumor necrosis factor-α(TNF-α) has been thought to play a major role in neurological injury during global brain ischemia and subsequent reperfusion following resuscitation in cardiac arrest. So, we hypothesized that the elevation in TNF-α was dependent upon the duration of the global brain ischemia, and related to delayed neuronal damage. Methods : Fourteen rats were divided two groups ; 1 minute-cardiac arrest group(n=7) and 3 minute-cardiac arrest group(n=7). we induced cardiac arrest by chest compression and clamping of tracheal tube for 1 minute and 3 minutes respectively. And then, resuscitation was initiated. To measure the plasma activity of TNF-α, blood samples were drawn before and at the end of cardiac arrest, and 30, 60, 90, and 120 minutes after initiation reperfusion. At 72 hours after resuscitation, the ND(neurologic deficit) score was determined and the histopathologic outcome of hippocampal CA1 neuron was observed by the percent dead hippocampal CA1 neurons. Results : 1. TNF-α level during the early reperfusion period(<2h) was significantly increased in 3 min-cardiac arrest group compared with 1 min-cardiac arrest group(p=0.0001). 2. There was a no significant difference of neurologic deficit score between 1 min-and 3 min-cardiac arrest. 3. Percent dead hippocampal neurons were significantly increased in 3 min-cardiac arrest group compared with 1 min-cardiac arrest group(9.1±1.2% vs 1.2±0.9%, p<0.05). Conclusions : The results suggest that longer duration of global brain ischemia causes a more profound increase in plasma TNF-α level during the early reperfusion period(<2h) and more delayed neuronal damage than lessor duration of global brain ischemia, and that increase in TNF-α level during the early reperfusion period(<2h) is related to delayed neuronal damage.

폐암과 동반되어 나타난 기관기관지병증 골연골형성증 1예

이영진,전현수,박시형,김모세,김현주,이승헌,이영민,이현욱,이현경 仁濟大學校 白病院 2010 仁濟醫學 Vol.31 No.-

Tracheobronchopathia osteochondroplastica (TPO) is a rare benign disease of unknown etiology characterized by multiple cartilaginous or bony submucosal nodules, which project into the tracheobronchial lumen. Although some disorders were reported combined with TPO, these seemed to be considered casual. We report a case of TPO that combined with adenocarcinoma of lung. She was 50-year-old non smoking woman presented with chronic cough with right chest pain. Lung mass on right lower lobe was found on chest x-ray, so lung cancer was suspected. Multiple scattered whitish small elevations from trachea to bronchial trees were found on bronchoscopic exam. We mistook these lesions for metastases from lung cancer and biopsies of these lesions were done. Transbronchial biopsy for right lower lobe mass lesion was also done. But biopsies from trachea and bronchus revealed TPO rather than lung cancer. Transbronchial lung biopsy of right lower lobe mass was diagnosed adenocarcinoma of lung. So TPO combined with adenocarcinoma of lung was diagnosed.

Most Probable Number 방법을 이용하여 측정한 중랑천 河床土壤의 혐기성 세균의 수와 수질과의 상관 관계

박두현,김병홍,임시근,최영효 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.3

중랑천의 하상 토양의 혐기성 호흡세균의 분포를 MPN법으로 조사하였다. 철이온환원세균을 조사하기 위해 배양액 중의 Fe(Ⅱ)을 확인하는 변형된 oxalate-ferrozine 법을 개발하였으며, 황산염환원세균(SRB)과 메탄생산세균을 각각 FeS 침전과 head space의 CH_4를 검출하는 방법을 채택하여 중랑천 지천과 본천의 혐기성 미생물 분포를 조사한 결과 오염 정도가 상대적으로 높은 본천에서 철이온환원세균이 10^7~10^8 cells/g 정도로 조사되었으며 지천의 경우 10^7 cells/g이었다. 우이천 상류를 제외한 모든 조사 지점에서 SRB와 methanogen 이 10^3 cells/g이었다. 이 결과는 분류 하수관의 설치로 유기물의 유입이 낮아진 조건에서도 하상의 침전층에서 유래하는 유기물을 이용하여 철이온환원세균이 생장할 수 있으며, SRB와 methanogen의 생장은 철이온환원세균에 의해 방해를 받는다는 것을 나타낸다. Sediments collected from the Jungnang-cheon and its tributaries were used to enumerate anaerobic bacteria by most probable number (MPN) methods. A simple method was developed to detect ferrous ion in the culture fluid in order to count the number of iron ion reducers, and sulfate-reducing bacteria (SRB) and methanogens were detected by the presence of FeS precipitate in the culture or methane in the head space, respectively. The numbers of iron reducer was in the range of 10^7~10^8/g in the sediment of the stream containing higher organic content than the tributaries. The sediments of tributaries were analyzed to contain iron reducers less than 10^7 cells/g. With one exception the numbers of SRB and methanogens were less than 10^3 cells/g in the sediment. From these results it is concluded that organics in the sediment support the growth of iron reducers, which out-compete SRB and methanogens.

음전하를 띤 Microsphere 에 의한 정전기적 반발력이 정밀여과에서 투과 플럭스에 미치는 영향 고찰

박정민,최성욱,방시원,함승주,김중현,김우식 한국화학공학회 2001 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.39 No.6

본 연구에서는 일정 압력하에서 음전하를 띤 microspheres의 정전기적 반발력에 따른 투과 플럭스의 변화에 관하여 고찰하였다. Microsphere의 정전기적 반발력에 관한 영향을 관찰하기 위해 표면전하 밀도(N_c: 0.45, 5.94, 10.25)가 각각 다른 poly(Styrene/Methacrylic acid) microspheres를 제조하였다. 교반속도는 300, 400, 600 rpm, 이온강도는 0.1, 0.01, 0.001로 변화시켜 실험하였다. 투과 플럭스는 표면전하밀도, 교반속도, 이온강도에 큰 영향을 받음을 알 수 있었으며, 투과 플럭스는 표면전하밀도가 클수록, 교반속도가 증가할수록, 이온강도가 작을수록 증가함을 알 수 있었다. 교반속도가 크면 막표면의 농도분극층의 두께가 얇아지기 때문에 투과 플럭스는 증가한다. 이온강도가 작을수록, 표면전하밀도(surface charge density)가 클수록 투과 플럭스가 커지는 원인은 microspheres의 정전기적 이중 층의 두께가 두꺼워짐에 따라 입자 사이의 거리가 멀어져 공극률(porosity)이 커지기 때문이다. 정상상태 플럭스 자료로부터 비 저항 정의식을 이용하여 케이크층의 공극률을 구할 수 있었다. 전하를 나타내지 않는 polystyrene microspheres의 입자크기가 480㎚일 때 농도분극 층의 이론적인 공극률은 0.211이었고, microspheres의 표면이 methacrylic acid로 완전히 개질된 것은 비 저항정의식에 의해 3.04로 계산되었다. 또한 microspheres들간의 정전기적 상호작용력이 작아지면 농도분극층의 공극률도 줄어드는 것을 알 수 있었다. The effect of the surface charge density(N_c: 0.45, 5.94, 9.14 and 10.25) and the stirrer speed(300, 400 and 600 rpm) on the variation of permeate flux was investigated in a stirred cell filled with negatively charged microspheres under constant pressure. It was found that the permeate flux depended on the surface charge density, the ionic strength and the stirrer speed. High permeate flux was obtained in the condition of high surface charge density, low ionic strength and high stirrer speed due to the force of electrostatic interaction between microspheres. The porosity of a cake layer was calculated from the steady-state flux data. It was found that the reduction of porosity was due to a decrease in repulsive interaction between microspheres.

석면함유 슬레이트 지붕 물받이 퇴적물 중 석면 섬유 함유율

임지현,한솔민,김현석,신유민,박시은,허정윤,김민영,장봉기 순천향대학교 기초과학연구소 2022 순천향자연과학연구 논문집 Vol.28 No.1,2

This study attempted to determine the degree of asbestos release from the aging slate roof by comparing the asbestos content in the slate roof rain gutter with a colored steel plate (tin plate) over the slate roof. Four slate roof houses located in Haengmok-ri, Asan-si, Chungcheongnam-do, and one house constructed with a colored steel plate on the slate roof were selected to collect the sediment of the roof rain gutter. The asbestos fiber content was calculated by a point counting method using a polarization microscope after pretreatment with conversion treatment and hydrochloric acid treatment. The average asbestos content of the four slate roof rain gutter were 1.89%. However, asbestos was not detected in the Slate covering roof rain gutter, which were constructed on the slate roof. Asbestos fiber content was the highest at 2.89% in the slate roof rain gutter installed in 1976, followed by 2.44% in 1953. From the above results, it is necessary to minimize secondary damage as asbestos fibers released from slate roof houses to the surrounding atmosphere or leaked from slate roofs as rainwater may cause soil pollution and seriously affect residents' health. Although covering with colored steel plates (tin plates) has been shown to prevent the leakage of asbestos fibers to some extent, it is believed that a policy alternative to remove the slate roof as soon as possible is needed to solve the fundamental problem.