• 사물인터넷융복합논문지
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• 제6권4호
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• pp.7-14
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• 2020

본 연구는 2010년 1월부터 2018년 12월까지 일산화탄소의 12일 단기 노출에 따른 순환계통 질환 사망자 수의 영향관계를 분석하였고, 일산화탄소 농도 증가에 따른 미래의 순환계통 질환의 진료비용을 예측하였다. 한국환경공단의 대기환경정보(Airkorea)와 한국 통계청에서 자료를 추출하였고, 포아송 회귀분석과 ARIMA 개입 모형을 사용하여 분석하였다. 통계처리는 SPSS Ver. 21.0 프로그램을 이용하였다. 연구 결과는 다음과 같다. 첫째, 일산화탄소의 단기 노출에 따른 순환계통 질환 사망에 영향관계를 당일부터 이전 11일 전까지 분석한 결과는 이전 11일에서 가장 높은 영향력이 있는 것으로 나타났다. 둘째, 일산화탄소 농도 증가에 따라 미래의 순환계통 질환 진료비용은 2019년 예측값이 10,123십억원으로 2018년 12월 말의 관측값 9,443십억원보다 높게 나타났다. 또한 월별로 정리해 보면 순환계통 질환 진료비용은 계절변동이 반영되어 1월 보다 12월로 갈수록 높아진다는 것을 알 수 있었다. 이러한 연구를 통하여 일산화탄소와 같은 대기오염물질 증가에 따른 선제적 대응을 위하여 IoT를 활용한 다양한 기기 및 장비를 보급함으로써 모든 국민의 건강한 삶을 위한 미래가 실현될 수 있을 것이다.

• 대한환경공학회지
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• 제32권11호
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• pp.1030-1037
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• 2010

본 연구에서는 비점오염물질 관리를 위한 적정 수변완충폭의 산정 방안과 산정된 수변완충지역에 식재되는 식생 유형에 따른 탄소 축적 효과를 비교하여 수변지역을 친환경적으로 관리하기 위한 방안을 제시하였다. 낙동강 중.하류지역인 낙본 K 유역을 대상으로 수행한 연구 결과 대상 하천에 30~600 m 범위의 수변 폭이 필요한 것으로 분석되었으며, 산출된 수변완충지대 조성 지역에서 논, 밭, 초지, 나대지 등 수변 조성이 용이한 지역은 총 1,776.51 ha로 산출된 지역의 약 50%로 나타났다. 조성이 용이한 1776.51 ha에 활엽수림으로 수변완충지역을 조성할 경우 약 14,526 ton, 혼효림으로 조성할 경우 11,826 ton, 침엽수림으로 조성할 경우 8,382 ton, 다년생 초지로 조성할 경우에는 3,349 ton의 탄소가 각각 매년 축적되는 것으로 나타났다. 본 연구의 결과 산정된 수변완충지역에 매년 흡수하는 이산화탄소량은 자동차 약 5천대에서 배출되는 이산화탄소량과 비슷하며, 4인 기준 가정 약 2만 가구에서 나오는 이산화탄소량과 유사한 양으로 파악되었다.

• 한국환경생태학회지
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• 제17권4호
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• pp.360-365
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• 2004

충청북도 충주지역에서 생육하는 굴참나무림에서 세근에 의한 지하부에서의 연간 탄소축적량을 조사하기 위하여 2001년 4월부터 11월까지 매달 토양샘플러를 사용하여 0-30cm, 30-60cm, 그리고 60-90cm 토양 깊이에서 샘플을 채취하였다. 세근에 의한 탄소생체량(fine root carbon biomass)은 다른 두 개의 조사 토양깊이에서 보다 0-30cm 토양깊이에서 가장 많은 것으로 나타났다. 세근에 의한 순탄소생산량 (kg/㏊/yr)은 0-30cm에서 671kg, 30-60cm에서 599kg, 그리고 60-90cm토양깊이에서 479kg로 나타났으며, 0-90cm토양깊이에서 세근에 의한 총 순탄소생산량은 1749kg이었다 세근고사율은 0-30cm에서 0.43, 30-60cm에서 0.96. 그리고 60-90cm에서 1.03로 나타났다. 세근고사율에 의한 토양으로의 연간 양분투입량은 N의 경우 33.9kg/㏊/yr, P의 경우 1.8kg, K의 경우 11.4kg, 그리고 Ca의 경우 20.1kg으로 나타났다.

• 한국환경과학회지
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• 제27권11호
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• pp.1095-1104
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• 2018

The adsorption characteristics of bisphenol A (BPA) were investigated using activated carbon based on waste citrus peel (which is abandoned in large quantities in Jeju Island), denoted as WCP-AC, and surface-modified with various $P_2O_5$ concentrations (WCP-SM-AC). Moreover, coconut-based activated carbon (which is marketed in large amounts) was surface-modified in an identical manner for comparison. The adsorption equilibrium of BPA using the activated carbons before and after surface modification was obtained at nearly 48 h. The adsorption process of BPA by activated carbons and surface-modified activated carbons was well-described by the pseudo second-order kinetic model. The experimental data in the adsorption isotherm followed the Langmuir isotherm model. With increasing $P_2O_5$ concentration (250-2,000 mg/L), the amounts of BPA adsorbed by WCP-SM-AC increased till 1,000 mg/L of $P_2O_5$; however, above 1,000 mg/L of $P_2O_5$, the same amounts adsorbed at 1,000 mg/L of $P_2O_5$ were obtained. With increasing reaction temperature, the reaction rate increased, but the adsorbed amounts decreased, especially for the activated carbon before surface modification. The amounts of BPA adsorbed by WCP-AC and WCP-SM-AC were similar in the pH range of 5-9, but significantly decreased at pH 11, and increased with increasing ionic strength due to screening and salting-out effects.

• 한국재료학회지
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• 제23권11호
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• pp.649-654
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• 2013

The effect of interstitial elements on the ductile-brittle transition behavior of austenitic Fe-18Cr-10Mn-2Ni alloys with different nitrogen and carbon contents was investigated in this study. All the alloys exhibited ductile-brittle transition behavior because of unusual low-temperature brittle fracture, even though they have a faced-centered cubic structure. With the same interstitial content, the combined addition of nitrogen and carbon, compared to the sole addition of nitrogen, improved the low-temperature toughness and thus decreased the ductile-brittle transition temperature (DBTT) because this combined addition effectively enhances the metallic component of the interatomic bonds and is accompanied by good plasticity and toughness due to the increased free electron concentration. The increase in carbon content or of the carbon-to-nitrogen ratio, however, could increase the DBTT since either of these causes the occurrence of intergranular fracture that lead to the deterioration of the toughness at low temperatures. The secondary ion mass spectroscopy analysis results for the observation of carbon and nitrogen distributions confirms that the carbon and nitrogen atoms were significantly segregated to the austenite grain boundaries and then caused grain boundary embrittlement. In order to successfully develop austenitic Fe-Cr-Mn alloys for low-temperature application, therefore, more systematic study is required to determine the optimum content and ratio of carbon and nitrogen in terms of free electron concentration and grain boundary embrittlement.

• Environmental Engineering Research
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• 제11권3호
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• pp.156-163
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• 2006

In this study, substrate removal characteristics were analyzed to reduce the cost of external carbon dosage at Sudokwon Landfill Site Management Corporation in Korea by utilizing oxygen uptake rate (OUR) and nitrate uptake rate (NUR) tests. To estimate and evaluate the substrate removal characteristics obtained by the batch tests, the lab-scale MLE process was operated. By-products of J Co. (sugar manufactory) and S Co. (fine chemical industry) were selected as the concerned carbon sources through a comparison of carbon and nitrogen contents. MeOH was tested as a control experiment. Until the steady state, the fraction of $RBDCOD_{OUR}$ concentration to COD concentration of J Co., S Co. by-products and MeOH increased and reached levels of 98%, 82%, and 100%, respectively. During the 20th operating day, the fraction of $RBDCOD_{NUR}$ concentration to COD concentration was 95%, 81%, and 83%, respectively. These fractions of $RBDCOD_{NUR}$ concentration to $RBDCOD_{OUR}$ concentration increased according to acclimation periods and reached levels of 99%, 97%, and 81%, respectively, on the 20th day. The results obtained from the lab-scale MLE process operation using the concerned carbon sources as external carbon were similar to that observed by OUR and NUR tests.

• 디지털융복합연구
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• 제11권9호
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• pp.247-254
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• 2013

본 연구는 탄소 면상발열체를 퇴행성 슬관절염 환자에게 적용하여 통증과 기능정도를 알아보는 목적으로 시행되었다. 연구 대상자는 2010년 7월부터 2010년 9월까지 C지역에 세 기관에서 총 45명을 대상으로 실험하였다. 대조군(n=15, 여성노인, 무처치)과 기존 세라믹 원적외선군(n=15, 여성노인, 원적외선 적용), 탄소 면상발열체군(n=15, 여성노인, 탄소면상발열체 적용)로 분류하고 치료는 1주에 3회, 3주씩 총 9회 30분씩 원적외선을 양 무릎에 적용하였다. 평가는 실험 전, 실험 후, 3주 후에 측정하였다. 처치후 VAS, PPT, K-WOMAC으로 평가하였다. 연구 결과를 통해 탄소 면상발열체를 사용한 원적외선 온열치료가 퇴행성 슬관절염의 통증감소와 기능향상 효과를 보인바 향후 임상에서 퇴행성 슬관절염 환자에게 치료방법의 하나로 사용 될 것으로 생각된다.

• 한국재료학회지
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• 제28권11호
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• pp.646-652
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• 2018

During a long-term operation of polymer electrolyte membrane fuel cells(PEMFCs), the fuel cell performance may degrade due to severe agglomeration and dissolution of metal nanoparticles in the cathode. To enhance the electrochemical durability of metal catalysts and to prevent the particle agglomeration in PEMFC operation, this paper proposes a hybrid catalyst structure composed of PtCo alloy nanoparticles encapsulated by porous carbon layers. In the hybrid catalyst structure, the dissolution and migration of PtCo nanoparticles can be effectively prevented by protective carbon shells. In addition, $O_2$ can properly penetrate the porous carbon layers and react on the active Pt surface, which ensures high catalytic activity for the oxygen reduction reaction. Although the hybrid catalyst has a much smaller active surface area due to the carbon encapsulation compared to a commercial Pt catalyst without a carbon layer, it has a much higher specific activity and significantly improved durability than the Pt catalyst. Therefore, it is expected that the designed hybrid catalyst concept will provide an interesting strategy for development of high-performance fuel cell catalysts.

• 농업과학연구
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• 제37권1호
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• pp.45-52
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• 2010

This study has been carried out to estimate carbon contents in an average 40-years-old Pinus koraiensis plantations and an average 37-years-old Larix leptolepis plantations in Gongju, Chungnam Province. Average carbon concentration in stemwood, stembark, branches, needles, and root were 54.31% in Pinus koraiensis and 53.49% in Larix leptolepis stands. Carbon contents was estimated by the equation model logWt=A+BlogD where Wt is oven-dry weight in kg and D is DBH in cm. Total carbon contents was 103.38tC/ha in Pinus koraiensis stands and 96.59tC/ha in Larix leptolepis stands. Net primary carbon production was estimated at 8.79tC/ha/yr in Pinus koraiensis stands and 11.42tC/ha/yr in Larix leptolepis stands.

• Journal of Electrochemical Science and Technology
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• 제11권3호
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• pp.220-237
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• 2020

Modern electrochemical energy devices involve generation and reduction of fuel gases through electrochemical reactions of water splitting, alcohol oxidation, oxygen reduction, etc. Initially, these processes were executed in the presence of noble metal-based catalyst that showed low overpotential and high current density. However, its high cost, unavailability, corrosion and related toxicity limited its application. The search for alternative with high stability, durability, and efficiency led scientists towards carbon nanoparticles supported catalysts which has high surface area, good electrical conductivity, tunable morphology, low cost, ease of synthesis and stability. Carbon nanoparticles are classified into two groups based on morphology, one and zero dimensional particles. Carbon nanoparticles at zero dimension, denoted as carbon dots, are less used carbon support compared to other forms. However, recently carbon dots with improved electronic properties have become popular as catalyst as well as catalyst support. This review focused on the recent advances in electrocatalytic activities of carbon dots. The mechanisms of common electrocatalytic reactions and the role of the catalysts are also discussed. The review also proposed future developments and other research directions to overcome current limitations.