• 한국토양환경학회지
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• 제4권3호
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• pp.3-15
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• 1999

기존의 SVE 공정에 공기 대신 오존을 주입하여 유류물질의 지중분해를 유도하고 추출가스의 처리부담을 최소화할 수 있는 복원 신공정 개발을 위한 기초연구를 수행하였다. 이를 위하여 비휘발성 유류물질인 디젤유를 처리대상물질로 하여 토양칼럼실험을 통해 오존주입에 의한 지중분해 가능성을 검토하였다. 수분함량 8.39%의 실토양에 디젤유를 혼합하여(초기농도 1,485mg-DRO/kg-soil)칼럼에 충진시킨 후 119.0$\pm$6.1mg/L의 농도를 가지는 오존가스를 50mL/min의 유량으로 연속 주입하였을 때 14시간 반응후 칼럼 상 하부의 디젤유 제거율은 각각 87.9%, 100.0%를 나타내어 비교적 빠른 시간내에 효과적으로 처리되는 것으로 나타났다. 한편 동일한 조건에서 오존가스 대신 공기를 주입하였을 때 공기 유입 및 유출부 모두 총 14시간 동안의 접촉시간 동안 30%이내의 제거율을 나타냄에 따라 디젤오염토양에 대한 기존 SVE공정의 적용한계를 확인하였다.

• Journal of Welding and Joining
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• 제24권5호
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• pp.57-61
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• 2006

For the production of functional $TiO_2$-biodegradable plastic (polybutylene succinate:PBS) composite material with photocayalytic activity, we attempted to prepare $TiO_2$ coatings on PBS substrate by HVOF and plasma spraying techniques under various conditions. The microstructures of coatings were characterized with SEM and XRD analysis, and the photocatalytic efficiency of coatings was evaluated by the photo degradation of gaseous acetaldehyde. The effects of primary particle size and spraying parameters on the formation behavior, photocatalytic performance of the coatings have been investigated. The results indicated that for both the HVOF sprayed $P_{200}$ and $P_{30}$ coatings, the high anatase ratio of 100% can be achieved regardless of fuel gas pressure. On the other hand, the HVOF sprayed $P_7$ coating exhibited a largely decreased anatase ratio (from 100% to 49.1%) with increasing the fuel gas pressure, which may be attributed to much higher susceptibility of heat for 7 nm agglomerated powder. HVOF sprayed $P_{200}$ and $P_{30}$ coatings show better performance as compared to that of plasma sprayed $P_{200}$ coatings owing to the higher anatase ratio. However, the HVOF sprayed $P_7$ coatings did not show the photocatalytic activity, which may result from the extremely small reaction surface area to the photocatalytic activity and low anatase ratio.

• 한국임상수의학회지
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• 제30권1호
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• pp.80-85
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• 2013

Twenty one cows in Goyang and Paju cities were referred due to displacement of the abomasum and foreign body in the rumen. Omentopexy and rumenotomy through a right flank celiotomy were performed for treatment of abomasal displacement and the foreign body removal in the rumen. The right paralumbar fossa is clipped and prepared surgically. Local anesthesia is instituted by performing inverted L block. The abdomen was entered through 25 to 30 cm vertical incision in the right paralumbar fossa starting 4 to 5 cm ventral to the transverse processes of the lumbar vertebrae. A 14-gauge needle with rubber tubing attached is inserted to relieve the gaseous pressure and to facilitate further exploration and manipulation. The rumen was gently pulled out of the abdominal cavity and incision was made at the omentum. Rumenotomy was done and retrieved the foreign body. After the rumen was rinsed with sterile saline, the rumen wall was closed by a Lembert suture technique. The omentum was closed by a simple continuous suture. Right flank omentopexy was performed for the surgical correction of abomasal displacement. Recovery results among 21 cows included 9 excellent, 5 good, 2 fair and 5 bad. It was considered that operation of abomasal displacement and foreign body removal in the rumen through right flank celiotomy was a good surgical technique to reduce expenses, surgical pain, and surgery time.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.27.1-27.1
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• 2011

The recent extensive research of one-dimensional (1D) nanostructures such as nanowires (NWs) and nanotubes (NTs) has been the driving force to fabricate new kinds of nanoscale devices in electronics, optics and bioengineering. We attempt to produce silicon oxide nanowires (SiOxNWs) in a simple way without complicate deposition process, gaseous Si containing precursors, or starting material of $SiO_2$. Nickel (Ni) nanoparticles (NPs) were applied on Si wafer and thermally treated in a furnace. The temperature in the furnace was kept in the ranges between 900 and $1,100^{\circ}C$ and a mixture of nitrogen ($N_2$) and hydrogen ($H_2$) flowed through the furnace. The SiOxNWs had widths ranging from 100 to 200 nm with length extending up to ~10 ${\mu}m$ and their structure was amorphous. Ni NPs were acted as catalysts. Since there were no other Si materials introduced into the furnace, the Si wafer was the only Si sources for the growth of SiOxNWs. When the Si wafer with deposition of Ni NPs was heated, the liquid Ni-Si alloy droplets were formed. The droplets as the nucleation sites induce an initiation of the growth of SiOxNWs and absorb oxygen easily. As the droplets became supersaturated, the SiOxNWs were grown, by the reaction between Si and O and continuously dissolving Si and O onto NPs. Photoluminescence (PL) showed that blue emission spectrum was centered at the wavelength of 450 nm (2.76 eV). The details of growth mechanism of SiOxNWs and the effect of Ni NPs on the formation of SiOxNWs will be presented.

• 한국대기환경학회지
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• 제19권6호
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• pp.719-731
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• 2003

In order to maintain and manage ambient air quality, it is necessary to identify sources and to apportion its sources for ambient particulate matters. The receptor methods were one of the statistical methods to achieve reasonable air pollution strategies. Also, receptor methods, a field of chemometrics, is based on manifold applied statistics and is a statistical methodology that analyzes the physicochemical properties of gaseous and particulate pollutant on various atmospheric receptors, identifies the sources of air pollutants, and quantifies the apportionment of the sources to the receptors. The objective of this study was 1) after obtaining results from the PMF modeling, the existing sources of air at the study area were qualitatively identified and the contributions of each source were quantitatively estimated as well. 2) finally efficient air pollution management and control strategies of each source were suggested. The PMF model was intensively applied to estimate the quantitative contribution of air pollution sources based on the chemical information (128 samples and 25 chemical species). Through a case study of the PMF modeling for the PM-10 aerosols, the total of 11 factors were determined. The multiple linear regression analysis between the observed PM-10 mass concentration and the estimated G matrix had been performed following the FPEAK test. Finally the regression analysis provided quantitative source contributions (scaled G matrix) and source profiles (scaled F matrix). The results of the PMF modeling showed that the sources were apportioned by secondary aerosol related source 28.8 ％, soil related source 16.8％, waste incineration source 11.5%, field burning source 11.0%, fossil fuel combustion source 10%, industry related source 8.3％, motor vehicle source 7.9%, oil/coal combustion source 4.4％, non-ferrous metal source 0.3％. and aged sea- salt source 0.2％, respectively.

• 한국어병학회지
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• 제6권1호
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• pp.65-70
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• 1993

아가미는 체조직 중에서도 가장 섬세하고도 미묘하게 적응된 조직학적 구조를 갖고 있을 뿐 아니라 환경수에 직접 노출되어 있기 때문에 수중의 각종 생물학적 및 물리화학적 유해인자에 쉽게 영향을 받을 수 있는 곳이다. 아가미를 구성하는 조직성분중에서도 특히 이차새변상피는 단층 내지 두층의 얇은 상피세포로 구성되어 있어 효율적인 가스교환을 할 수 있게 하지만, 이러한 구조의 특수성이 오히려 각종 유해 인자의 침입 또는 이들에 의한 손상을 쉽게 할 수 있다. 아가미는 호흡기능 뿐만 아니라, 장 및 신장과 함께 삼투압의 조절, 노폐물의 배설의 기능도 갖는다. 그러므로, 새변상피의 괴사나 비후와 같은 형태학적 변화는 호흡, 분비 및 배설기능의 장애를 야기할 수 있으므로 새변상피의 기능적 및 형태학적 유지는 무엇보다 중요하다 하겠다. 여기에서는 어떤 특정질병 또는 원인체에 관련한 병리조직학적 변화보다는 일반적으로 아가미조직의 조직학적 특수성을 우선 깊이 이해하고, 그 특성에 관련된 비특이적인 병리조직학적 변화를 중심으로 기술함으로써, 특정 원인체와의 병리조직학적 반응에 대한 보다 정확한 해석을 기하고자 이미 보고 및 출판된 정보를 토대로 하여 여기에 정리하였다.

• 한국환경과학회지
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• 제22권12호
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• pp.1539-1549
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• 2013

The purpose of this study is to compare the sampling methods for monitoring indoles (phenol, p-cresol, indole and skatole) in airs of swine facility. As the collecting methods of indoles in air, Tenax-TA adsorption tube and solid phase microextraction (SPME) were examined. For the preparation of calibration curves of indoles concentrated in Tenax-TA, the standard indoles solutions were spiked in each of Tenax-TA tubes and thermally desorbed (ATD) into a gas chromatograph combined with mass detector (GC/MS). And for the preparation of calibration curves by SPME, indoles in the standard gaseous solution prepared by evaporating the aqueous solution that contained indoles into a polyester sampling bag were extracted with SPME fiber and subsequently analyzed by the GC/MS. Two sampling methods were evaluated for extracting indoles present in swine building environments. Results indicated that the SPME method using Polydimethylsiloxane/ Divinylbenzene (PDMS/DVB) fiber was more effective than Tenax-TA method in extracting indoles. The gas chromatographic analysis showed that the linearities of calibration curves and detection limits were useful for detection of indoles in swine airs. The field tests also showed that considerably different levels of indoles were present in various parts of the swine building.

• 전기학회논문지
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• 제60권8호
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• pp.1560-1565
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• 2011

The environmental pollution caused by green-house gases such as $CO_2$ and $SF_6$ has been becoming the main issue of industrial society. Many developed countries are making efforts to minimize the amount of $CO_2$ emission come from the operation of high voltage electrical apparatuses. As a part of these efforts, 180 countries signed the Kyoto Protocol in 1997 to cut back on their green-house gas emissions. Nowadays, the study on the development of dry air insulated switchgear (DAIS) which is known as an eco-friendly electrical apparatus is in progress. A DAIS is advantageous for minimizing the effect of impurities and enhancing the dielectric characteristics over an air insulated switchgear (AIS) by applying constant pressure to an enclosed cubicle. Therefore, a study on the electrical insulation performance of dry air as a gaseous insulation medium is conducted in this paper to substitute a gas insulated switchgear (GIS) for DAIS. As results, it is verified that the AC dielectric characteristics of dry air are similar to those of air and the lightning impulse dielectric characteristics of dry air are superior to those of air at 1bar pressure condition. However, dry air is of inferior dielectric characteristics to $SF_6$ at 4bar pressure condition. Finally, it is suggested that the internal pressure of DAIS should be over 4bar pressure to develop a high voltage switchgear which has similar electrical performance to a conventional GIS. Also, the empirical formulae on calculating the maximum electric field intensity at sparkover of dry air are deduced by experiments according to pressures. It is expected that these results are helpful to design and develop a high voltage electrical apparatus.

• 한국한의학연구원논문집
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• 제12권3호통권18호
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• pp.49-58
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• 2006

Although the usage of acupuncture for pain has increased in recent years, the mechanisms of acupuncture analgesia (AA) remain unclear. The lack of suitable experimental animal models for persistent pain, which show clear AA, has been the major stumbling block in the investigation of the physiological mechanisms of AA. In the present study, we test AA in two knee arthritis models induced by injection of CFA or carrageenan as persistent pain models. After induction of arthritis, the rat subsequently showed a reduced stepping force of the affected limb for the next several days. Electroacupuncture (EA) was applied to an acupuncture point each on the contralateral forelimb for 30 minutes under gaseous anesthesia. After the termination of EA, behavioral tests measuring stepping force were periodically conducted during the next several hours. EA produced a significant improvement of stepping force of the foot lasting for at least 2 hours when applied to LR2 in CFA model, and applied to ST36 in carrageenan model, but both points did not produce any significant effects in each other model. Further experiments showed that intraperitoneal pretreatment of naltrexone, a non-selective opioid antagonist, did not reduced the EA-induced improvement of stepping force in both of two models. These data suggest that EA produce analgesic effect in knee arthritic pain and the analgesic effect is specific to the acupuncture point depending on painful conditions.

• 조명전기설비학회논문지
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• 제18권5호
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• pp.35-41
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• 2004

본 연구에서 사용된 방전 기체는 오염물의 제거 및 박막 표면 정제 등의 연구 분야에 응용되고 있는 질소 가스를 사용하였으며, 1차원 동심구 모델의 개발로 인하여, 접지 면적을 넓게 함에 따라 경방향으로의 플라즈마 분포가 중심축의 분포와 동일하다는 1차원적 가정이 적절하지 못하다는 Barnes 모델을 보완할 수 있었다. 일정한 인가 전압하에서는 입체각($\omega$)의 증가에 따라 질소 플라즈마를 구성하는 각 입자의 수밀도 분포, 전계 및 포텐셜이 감소함을 볼 수 있었다. 그러나 면적비가 증가하면서 구동 전극에서의 각 입자들의 움직임은 상대적으로 높은 전계로부터 더욱 활발하게 형성됨에 따라 직렬 연결된 블로킹 콘덴서에서 발생하는 자기 바이어스 전압은 증가하는 것을 알 수 있었다.