• Biotechnology and Bioprocess Engineering:BBE
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• 제8권2호
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• pp.117-125
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• 2003

Experimental and theoretical works were performed for the separation of large polyelectrolyte, such as DNA, in a column packed with gel particles under the influence of an electric field. Since DNA quickly orient in the field direction through the pores, this paper presents how intraparticle convection affects the residence time distribution of DNAs in the column. The concept is further illustrated with examples from solid -liquid systems, for example, from chromatography Showing how the column efficiency is improved by the use of a n electric field. Dimensionless transient mass balance equations were derived, taking into consideration both diffusion and electrophoretic convection. The separation criteria are theoretically studied using two different Peclet numbers in the fluid and solid phases. These criteria were experimentally verified using two different DNAs via electrophoretic mobility measurements. which showed how the separation position of the DNAs varies in the column in relation to the Peg/Pef values of an individual DNA. The residence time distribution was solved by an operator theory and the characteristic method to yield the column response.

• 조명전기설비학회논문지
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• 제24권6호
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• pp.131-137
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• 2010

가정용에서 사용되고 있는 에너지는 도시가스와 전기에너지로 구분할 수 있으며, 가정용 에너지 소비형태는 도시가스보다 전기에너지의 사용량이 증가하고 있다. 최근에는 저탄소 및 에너지 절감에 대한 이슈로 인해 전전화(全電化) 주택에 대한 관심이 높아지고 있는 실정이다. 이에 따라 누적된 에너지 소비 형태를 이용하여 가정용에서 소비된 에너지원별 사용량 및 에너지 지출비용을 분석하였다. 분석 결과 1차 에너지원인 도시가스 사용량의 감소와 더불어 전기에너지의 사용량이 점차 증가하고 있는 추세이다. 본 논문에서는 과거 25년간의 에너지 소비 이력 데이터를 이용하여 가정용에서 사용되는 에너지원의 사용량을 분석하고, 전전화 주택 도입 시 예상되는 전력량 및 열에너지 양과 에너지 비용을 분석하였다.

• 환경위생공학
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• 제11권1호
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• pp.9-15
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• 1996

The purpose of this study was to evaluate the decomposition efficiency of $NH_3$ odor gas using high frequency surface discharge body. The results from this study are as follows; 1, Voltage and frequency of electric elements have effects on removal of $NH_3$ odor. The higher these two elements were set up, the more efficiently deodorizing processing worked. In this experiment, the optimum voltage and frequency applicable were observed around AC 6.0 kVp-p and 24.0 kHz respectively. 2. The temperature, humidity and residence time were observed strong variables for NH$_3$ removal process. Its performance had limits at high temperature and humidity conditions. The longer the residence time continued, the more efficiently deodorization process worked. The experimental results showed that the deodorization was efficiently processed under such conditions as $30.0^{\circ}C$ in temperature, 60rh% in humidity and 0.3 sec in residence time. 3. It was observed that in deodorization experiment, $NH_3$ odor gas was perfectly decomposed under the concentration condition below 15.0ppm. Moreover it was considered as economic and practical in terms of maintenance cost when compared with other deodorization methods.

• 한국안전학회지
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• 제8권3호
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• pp.34-43
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• 1993

This paper presents a study on the characteristics and safety criteria for human body in ELF (Extremely Low Frequency : 50-60Hz) electric and magnetic fields. Many researches for ELF electric and magnetic fields, which are developed in the past, are studied and analyzed In this paper. In order to estabilish the safety criteria for human body in the field, the field intensity, induced current and voltage are calculated by the electrostatic field approach which is far simpler than the electromagnetic field one based on Maxwell equation. The method is applied to the 345 KV transmission line system In operation and 765 KV system under consideration. According to the results, the maximum value of field intensity, 6.8627KV/m, is evaluated at the location which is 14m away from transmission line. As the safety criteria value by the abroad researches asserting that the human can detect the Induced current in 6KV/m and above, 5KV/m and 7KV/m are recommended at residence area and nonresidence area, respectively.

• 연구논문집
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• 통권28호
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• pp.39-47
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• 1998

Industrial electrostatic precipitation is a very complex process, which involves multiple-way interaction between the electric field, the fluid flow, and the particulate motion. This paper describes a strongly coupled calculation procedure for the rigorous computation of particle dynamics during electrostatic precipitation. The turbulent gas flow and the particle motion under electrostatic forces are calculated by using the commercial computational fluid dynamics (CFD) package FLUENT linked to a finite-volume solver for the electric field and ion charge. Particle charge is determined from both local electrical conditions and the cell residence time which the particle has experienced through its path. Particle charge density and the particle velocity are averaged in a control volume to use Lagrangian information of the particle motion in calculating the gas and electric fields. The turbulent particulate transport and the effects of particulate space charge on the electrical current flow are investigated. The calculated results for poly-dispersed particles are compared with those for mono-dispersed particles, and significant differences are demonstrated.

• Current Optics and Photonics
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• 제7권4호
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• pp.463-470
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• 2023

Hydroxygraphene as a kind of functionalized graphene has important applications in composite, photoelectric and biological materials. In the present study, THz and microfluidic technologies were implemented to study the THz transmission characteristics of hydroxygraphene with different concentrations and residence times in magnetic and electric fields. The results show that the THz transmission intensity decreases with the increase in sample concentration and duration of an applied electric field, while it increases by staying longer in the magnetic field. The phenomenon is analyzed and explained in terms of hydrogen bond, conductivity and scattering characteristics. The results establish a foundation for future research on the THz absorption characteristics of liquid graphene based on microfluidic technology in different external environments. It also provides technical support for the application and development of graphene in THz devices.

• 한국자동차공학회논문집
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• 제17권5호
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• pp.46-52
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• 2009

In this study the predictions of NOx in methane-air lean premixed combustion in PSR were carried out with GRI 3.0 methane-air combustion mechanism and Zeldovich, nitrous oxide, prompt, and NNH NO formation mechanism by using CHEMKIN code. The results are compared to the JSR experimental data of Rutar for the validation of the model. This study concerns about the importance of the chemical pathways. The chemical pathway most likely to form the NO in methane-air lean-premixed combustion was investigated. The results obtained with the 4 different NO mechanisms for residence time(0.5-1.6ms) and pressure(3, 4.7, 6.5 atm) are compared and discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.6-11
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• 2007

Packaged power station (PPS) is a stationary diesel engine generator set and developed for the supply of electric power to small villages, islands and factories etc. Therefore, the PPS is closely installed to residence area and sometimes cause the environmental noise problems. In this paper, environmental noise analysis was performed for the power plant with 28 sets of PPS. The initial analysis results showed the some difference between the measurement and analysis because of the inaccurate noise source data. To improve the accuracy of analysis, main noise sources were inversely estimated using the in-situ measurement data in the vicinity of PPS and steam boiler. As the results of re-analysis, the good agreement was obtained and it was concluded that the noise levels exceed the specified noise limit in residence area. In order to reduce the noise, the several methods such as geometry alteration of inlet duct, application of hybrid-type silencer and noise protection barrier were suggested and verified with the confirmed analysis model.

• 디지털융복합연구
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• 제16권5호
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• pp.213-220
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• 2018

우리나라의 자동차 산업은 국가 경제에 미치는 비중이 매우 큰 산업분야이다. 현재는 전 세계적으로 저탄소 녹색성장에 대한 관심이 날로 커지면서 자동차 산업의 미래경쟁력에 적극적인 확보를 해야 할 시대가 도래 하였다. 따라서, 기술적 사회적 변화가 예상되는 시점에서 전기 자동차에 대한 소비자의 구매 태도 및 의도에 관한 연구는 반드시 필요하다. 본 논문은 250명을 대상으로 전기자동차에 대한 수용성 및 선호도를 조사하였으며 결과는 다음과 같다. 월소득이 적을수록, 거주자 수가 많을수록 전기자동차를 수용하겠다고 결정하였으며, 전기자동차가 소비자에게 미치는 영향이 클수록, 전기자동차는 소비자가 전기자동차에 대한 관심이 클수록 전기자동차를 수용하겠다고 결정하였다. 그리고, 인구통계학적 특성 중 세 가지(월소득, 거주수, 거주형태)는 전기자동차의 만족도에 대한 차이는 있는 것으로 나타났다. 전기자동차의 만족도를 분석한 결과, 전기자동차는 소비자에게 미치는 영향이 크면 클수록 전기자동차에 약 3.5배 만족하며, 전기자동차에 대한 소비자의 관심이 크면 클수록 전기자동차에 약 2.1배 만족하는 것으로 나타났다.

• 한국수소및신에너지학회논문집
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• 제16권4호
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• pp.364-371
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• 2005

Fuel cell systems(FCS) have a financial and environmental advantage by providing electricity at a high efficiency and useful heat. For use in a residence, a polymer electrolyte fuel cell system(PEFCS) with a battery pack and a hot water storage tank has been modelled and simulated. The system is operated without connection to grid line. Its electric conversion efficiency and heat recovery performance are highly dependent on operation strategies and also on the seasonal thermal and electric load pattern. The output of the fuel cell is controlled stepwise as a function of the state of the battery and/or the storage water tank. In this study various operation strategies for cogeneration fuel cell systems are investigated. Average fuel saving rates at different seasons are calculated to find proper load management strategy. The scheme can be used to determine the optimal operating strategies of PEFCS for residential and building applications.