• 한국공작기계학회논문집
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• 제15권1호
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• pp.76-81
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• 2006

Modem after-treatment technology has been developed variously in order to decrease exhausted emission in diesel engine. However, it seems very difficult to comply with updated stringent emission standards. Specially, it has been many years that exhaust gas from gasoline automobile rather than from diesel is the major object concerned by Korea and other countries, and it is strongly required on the reduction techniques on harmful NOx and PM among those compositions. Thus, this research focused on the electronic control EGR and the target for this research is heavy-duty turbo-diesel engine with EGR technology(High pressure route and low pressure route system).

• 한국산학기술학회논문지
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• 제3권1호
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• pp.58-62
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• 2002

본 연구는 기관의 성능과 배출가스의 ECR 효과을 대한 것으로 기관은 6실린더 11리터의 대형터보디젤기관이며 ECR 방식은 저압루트시스템을 적용하였다. EGR 작동방식은 기계시이며 터빈 출구로부터 압축기 입구로 재순환시키는 방식이다. 또한 실험은 기관회전수와 부하별로 변경시켰으며 ECR율은 4%와 8%로 고정하여 실험하였고 그 결과를 기존 기관의 성능 및 배출가스결과와 비교 분석하였다. 따라서 본 연구의 목적은 대형터보디젤기관에 폭넓은 작동범위에서 ECR에 의한 기관 및 배출가스 성능에 미치는 영향을 고찰하고자 한다.

• 한국자동차공학회논문집
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• 제10권6호
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• pp.59-64
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• 2002

The effects of EGR on emissions were investigated by using a six-cylinder, 8 litre, turbo-charged, heavy-duty diesel engine with a low pressure route EGR system. The experiments were performed at various engine loads while the EGR rates were set from 0% to 30%. Hot and cooled EGR are achieved without cooling and with cooling respectively. To verify the possibility of EGR technology for the applications, test were performed with steady state test cycle. It was found that the exhaust emissions with the EGR system resulted in a very large reduction in oxides of nitrogen at the expense of higher smoke and PM emissions. Increasing the EGR rate leads to deteriorating specific fuel consumption and power at lower speed and higher load. Also, the reduction rates of NOx emissions for hot and cooled EGR are similar.

• 한국재료학회지
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• 제18권3호
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• pp.123-127
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• 2008

The production of tin oxide ($SnO_2$) microrods on iridium (Ir)-coated substrates was achieved through the thermal evaporation of Sn powders in which a sufficiently high $O_2$ partial pressure was employed. Scanning electron microscopy revealed that the product consisted of microrods with diameters that ranged from 0.9 to $40\;{\mu}m$. X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction indicated that the microrods were $SnO_2$ with a rutile structure. As the microrod tips were free of metal particles, it was determined that the growth of $SnO_2$ microrods via the present route was dominated by a vapor-solid mechanism. The thickening of rod-like structures was related to the utilization of sufficiently high $O_2$ partial pressure during the synthesis process, whereas low $O_2$ partial pressure facilitated the production of thin rods.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4137-4144
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• 2010

본 논문에서는 승용디젤엔진에서 유해배출물을 저감시키는 동시에 고연비를 달성하기 위하여 2단 터보과급기와 EGR 장치를 장착한 디젤엔진에 대하여 EGR 배열 방식이 EGR율에 미치는 영향을 분석하기 위하여 시뮬레이션을 수행하였다. 이를 위하여 AMESim을 사용하였고 엔진 부품을 위하여 IFP Engine Library를 사용하였다. 고압, 저압, 반저압의 3가지 배열 방식이 고려되었다. 일반적으로 많이 사용되는 고압 방식과 저압 방식의 EGR 배열이 공연비 21에서 각각 6.4%, 10.0%의 EGR율을 보인 반면, 두 방식의 혼합형인 반저압 EGR 배열 방식의 EGR율은 18.0%의 값을 보였다. 따라서 2단 터보과급기와 EGR 장치를 장착한 엔진 설계시 엔진 성능과 유해배출물 발생량의 관점에서 반저압 방식 EGR 시스템이 적절함을 보였다.

• 한국산업융합학회 논문집
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• 제21권1호
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• pp.29-36
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• 2018

Low pressure casting process for unidirectional carbon fiber reinforced aluminum (UD-CF/Al) composites which is an infiltration route of molten Al into porous UD-CF preform has been a cost-effective way to obtain metal matrix composites (MMCs) but, easy to cause non-uniform fiber distribution as CF clustering. Such clustered CFs have been a problem to decrease the density and thermal conductivity (TC) of composites, due to the existence of pores in the clustered area. To obtain high thermal performance composites for heat-sink application, the relationship between fiber distribution and porosity has to be clearly investigated. In this study, the CF distribution was evaluated with quantification approach by using two-dimensional spatial distribution method as local number 2-dimension (LN2D) analysis. Note that the CFs distribution in composites sensitively changed by sizes of Cu bridging particles between the CFs added in the UD-CF preform fabrication stage, and influenced on only $LN2D_{var}$ values.

• Korean Membrane Journal
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• 제10권1호
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• pp.13-19
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• 2008

Water softening is a very promising field for membranes and especially ultra low pressure membranes. Nanofiltration membranes based on pore-filling technology was prepared by using a new technique: the in-situ cross-linking. This route involves introducing a pre-formed polymer into the pores of a host membrane and then locking the polymer in the pores by in-situ cross-linking with an appropriate reagent. By this way, it is possible to make robust and competitive, pore-filled, anion-exchange membranes with excellent control over the properties of the incorporated gel without affecting the host membrane. In this paper, the possibilities of tuning such membranes for ultra low pressure water softening was examined by altering pore-filling chemistry (by changing cross-linking and aminating reagents). The results showed that tuning the chemistry of the pore-filling has important effects. In particularly, it had been shown that the correct selection of cross-linking reagent was not only essential to get pore-filled membranes but it could control their properties. Moreover, the aminating reagent could improve membrane performance. It was found that an increase in hydrophobicity could improve the Darcy permeability.

• Ocean and Polar Research
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• 제21권2호
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• pp.117-126
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• 1999

To meet increasing needs for environmentally sustainable management of coastal area, there has been compelling pressure to establish a cost-effective and long-term coastal water quality (CWQ) monitoring system. A remote CWQ monitoring system, STAMP, has been developed and is in operation along the route between Kyema harbor and Anma Island in the southwestern coastal area of Korea. STAMP uses a PCS phone as a telemetry unit to transmit acquired data for monitoring general water quality parameters, and a routinely operating coastal passenger ship or car ferry. STAMP has various merits of low-cost operations; long-term monitoring with secure instrumentation; and stable real-time telemetry of acquired data with-out the loss and noise. It is expected that the system will serve as a very useful tool in the CWQ managing programs of Korea taking the advantage of many coastal passenger ships in various routes including the ships departing from the coastal industrial cities. The acquired data compiled on suspended surface sediment concentrations (SSSC) will be also valuably helpful in understanding the sediment budget across the routes of the vessel.

• Journal of Chest Surgery
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• 제15권2호
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• pp.218-221
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• 1982

Delayed cardiac tamponade in an uncommon and frequently fatal complication after open-heart surgery. We had been experienced two cases of delayed cardiac tamponade as a complication of open-heart surgery and treated successfully by reinsertion of pericardial drain through subxiphoid route. First case was 60 years old female patient and underwent MVR under impression of MSi + Ti Second case was 19 years old male patient and underwent total correction of T.O.F.with Blalock shunt [Lt]. Both cases had Initial symptoms, which were epigastric pain, chest tightness, dropped blood pressure, and increased pulse rate and respiratory rate, mimic as low cardiac output syndrome after open-heart surgery. Roentgenogram of the chest showed a rapid increased cardiothoracic ratio. It is important to realize the presence of late cardiac tamponade for proper diagnosis of complication after open-heart surgery.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권7호
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• pp.3100-3116
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• 2016

With the rapid development of urban traffic system and fast increasing of vehicle numbers, the traditional centralized ways to generate the source-destination shortest path in terms of travel time(the optimal path) encounter several problems, such as high server pressure, low query efficiency, roads state without in-time updating. With the widespread use of smart cameras in the urban traffic and surveillance system, this paper maps the optimal path finding problem in the dynamic road network to the shortest routing problem in the smart camera networks. The proposed distributed optimal path generation algorithm employs the delay routing and caching mechanism. Real-time route update is also presented to adapt to the dynamic road network. The test result shows that this algorithm has advantages in both query time and query packet numbers.