• 반도체디스플레이기술학회지
• /
• 제16권4호
• /
• pp.11-15
• /
• 2017

Red phosphors, $Sr_2Si_5N_8:Eu^{2+}$, were synthesized as a single-phase crystal structure by optimizing carbon and $Eu^{2+}$ contents in a carbothermal reduction nitridation method. With increasing $Eu^{2+}$ contents, the photoluminescence spectra were red-shifted from 600 nm peak for 1 mol% for to 700 nm for 7 mol%. It was suggested that this red shift is attributed to the energy transfer from one low-energy sited $Eu^{2+}$ (1) to other high-energy sited $Eu^{2+}$ (2). Finally, the best red sample (620 nm emission peak and 80 nm half width for 3 mole% of $Eu^{2+}$) was packaged on a Blue LED together with two additional green and yellow phosphors, the fabricated White LED showed a high color-rendering index of 90 and white color coordinates of x= 0.321 and y = 0.305.

• 한국전기전자재료학회논문지
• /
• 제16권8호
• /
• pp.744-751
• /
• 2003

Co-Pd alloy thin films prepared by a DC-sputter that have self-organized nano structure(SONS), are promising for high-density information storage media in information era. We prepared the samples by varying Pd contents of 0~8.1 wt% at the substrate temperatures of room temperature (RT) and 200 $^{\circ}C$, respectively Microstructure and Pd contents of the Co$_{1-x}$ Pd$_{x}$ films are probed by a scanning electron microscope (SEM), a transmission electron microscope (TEM) and an energy dispersive spectrometer (EDS). We also investigated the saturation magnetization (Ms), remanence and coercivity of the Co$_{1-x}$ Pd$_{x}$ films. Surface roughness are measured by an atomic force microscope (AFM). We revealed that self-organized nano size Co-enriched phase and Pd-enriched phase existed with Pd contents at the substrate temperatures of RT and 20$0^{\circ}C$ through microstructure characterization. SONS helped to keep the saturation magnetization and enhance the perpendicular anisotropy with Pd contents. Out result implies that we may tune the perpendicular magnetic properties with keeping the saturation magnetization by varying substrate temperatures and Pd contents for high density magnetic recording.rding.

• 한국농공학회논문집
• /
• 제50권4호
• /
• pp.59-66
• /
• 2008

Anaerobic digestion system is getting more attractive in that it produces biogas in the process of organic waste stabilization. Net energy production is important when biogas production is concerned. In this study, net energy production was evaluated with respect to biogas production and heat losses in a hypothetical digester. Under the condition of digester operation with slurry inflow of 5% of TS, additional fuel is required to maintain digester temperature during the winder season. Substrate therefore, needs to have higher VS contents through co-digestion of silage or food waste that has greater values of methane production rate. Heating input slurry is important in cold season, which covers over 80% of heating requirement. Heat recovery from digestate is valuable to reduce the use of biogas for heating. It seems desirable to minimize slurry inflow when temperature is very low. Psychrophilic digestion may be a feasible option for reducing heating requirement.

• 한국분말재료학회지
• /
• 제15권2호
• /
• pp.87-94
• /
• 2008

In order to investigate a nitriding process of spent oxide fuel and the subsequent change in thermal properties after nitriding, simulated spent fuel powder was converted into a nitride pellet with simulated fission product elements through a carbothermic reduction process. Nitriding rate of simulated spent fuel was decreased with increasing of the amount of fission products. Contents of Ba and Sr in simulated spent fuel were decreased after the carbothermic reduction process. The thermal conductivity of the nitride pellet was decreased by an addition of fission product element but was higher than that of the oxide fuel containing fission product elements.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2006년도 하계학술발표대회 논문집
• /
• pp.1019-1025
• /
• 2006

There are so many related policies to design and construct building mechanical system. Therefore, preferentially in this study, purposes and major contents of related laws are summarized briefly. Subsequently, some points at issue and ways to improve laws and codes for energy conservation are suggested. From the results of this study, some points at issue are as follows : (1) Inconvenience in the application due to dispersion of similar codes. (2) Lack of systems and tools to verify and to evaluate the effect of energy conservation by any policy (3) Lack of the incentive Policy for Participator to conserve of energy.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 1996년도 학술발표회 논문집
• /
• pp.309-317
• /
• 1996

• 한국콘텐츠학회논문지
• /
• 제18권3호
• /
• pp.611-625
• /
• 2018

최근 무선 통신 기술의 혁신적인 발전에 따라 에너지 하베스팅을 통해 네트워크 수명을 영구적으로 연장하기 위한 네트워크 자원 최적화, QoS 보장 전송 기법, 에너지 지능적 라우팅 등의 연구가 활발히 진행되고 있다. 잘 알려진 바와 같이 다중-홉 RF 에너지 하베스팅 무선 네트워크에서는 수확되는 에너지양의 불확실성 때문에 종단간 네트워크 전송 지연 시간을 보장하기 어려운 문제가 발생한다. 본 논문에서는 다중 홉 에너지 하베스팅 무선 네트워크에서 종단간 지연 시간을 최소화하기 위하여 상호채널 간섭(co-channel interference)으로 인한 지연, 에너지 하베스팅 시간으로 인한 지연 그리고 중계 노드에서의 큐잉 지연을 종합적으로 고려한 간섭 인지 기반의 에너지 효율적인 라우팅 메트릭과 프로토콜을 제안한다. 제안된 기법은 부하 불균형을 유발하는 패킷 혼잡을 회피하고 에너지 고갈로 인한 노드의 대기 시간을 줄이며 링크 간의 간섭으로 지연시간이 증가되지 않도록 함으로써 종단간 처리량을 최대화한다. 마지막으로 ns-3 시뮬레이터를 이용하여 처리율, 종단간 지연시간, 에너지 소비량 등의 측면에서 제안된 기법의 성능을 측정하여 기존에 제안된 기법보다 성능이 우수함을 증명한다.

• 한국환경교육학회지:환경교육
• /
• 제24권2호
• /
• pp.70-85
• /
• 2011

The purpose of this study was to investigate the influence of the energy campaign environmental education of 3rd graders in elementary school in Seoul. The students were divided into an experiment group and a control group. A reconstructed questionnaire through Kim(2005) and Lee(2005)'s test tool was used to survey the effects of applying the energy campaign environmental education program. The i-STATistics program was used to analyze the results. The major results of this study are as follows. First, the researcher was able to develop and apply teaching-learning model for energy campaign environmental education by extracting and recreating the energy education-related contents from the lower grades(1, 2, 3 grade) in 2007 elementary school curriculum. Second, this program had a positive effect on pro-environmental altitudes of elementary school students. Third, this program had a positive correlation among the 3 subdomains of cognitive, affective and behavioral. Fourth, according to qualitative analysis, the students appear to be more concerned in the overall environmental problems containing energy problem and showed a higher will to act while participating in the environmental education through energy campaign program. In conclusion, this program is more directly effective than lectures on energy following the curriculum to improve student's pro-environmental altitudes. Therefore, more intensive research on teaching and learning activities should be highly considered.

• International journal of advanced smart convergence
• /
• 제6권1호
• /
• pp.57-67
• /
• 2017

In this paper, propose an algorithm to improve network lifetime by equally consuming energy of LEACH - Mobile sensor nodes. LEACH is one of energy efficient protocols. However, we did not consider the mobility of nodes. Therefore, the transmission reception success rate of the moving data is reduced. LEACH-Mobile is a protocol that has improved the drawbacks of these LEACH. However, since LEACH-Mobile has a larger number of data packets and consumes more energy than LEACH, it has a disadvantage that the lifetime of the network is short. In order to improvement these disadvantage, Based on the average of the remaining energy of the node, cluster heads are elected with a number of nodes whose energies are larger than the average of the remaining energy from the member nodes. After that, by trying to increase the lifetime of the network by equalizing the remaining energy. In to confirm whether improve the lifetime of the network, In this paper, the number of nodes and the position of all nodes are varied for each specific round, the rest energy is equalized, and the algorithm which uniformly selected the cluster head is compared with LEACH.

• 에너지공학
• /
• 제23권2호
• /
• pp.199-206
• /
• 2014

ESCO 업계는 2013년 ESCO 규정의 개정으로 에너지절약성과 보증계약에 대한 역량을 강화하여야 한다. 이러한 시점에서 에너지절약성과에 대한 측정 검증(M&V)이 중요한 과제로 부각되고 있다. 이에 따라, 선진국의 M&V 적용사례 파악이 필요하다. 에너지사용자와 ESCO 기업 간의 에너지절약성과 보증계약 체결에 의한 에너지절약설치로 발생되는 에너지절감량을 측정 평가하는 방안을 제공하는 것이 무엇보다 중요하다고 할 수 있다. 2013년부터 성과보증계약 방식 위주의 ESCO 사업이 추진되기 시작하였다. 따라서 이러한 이유로 IPMVP에서 권고하고 미국이나 일본에서 적용하고 있는 M&V 사례 를 활용하여 우리나라의 ESCO 여건에 적합한 M&V 적용방안의 마련이 필요한 것으로 판단된다.