• 한국전기전자재료학회논문지
• /
• 제35권5호
• /
• pp.419-430
• /
• 2022

Defects in solids play a vital role on thermoelectric properties through the direct impacts of electronic band structure and electron/phonon transports, which can improve the electronic and thermal properties of a given thermoelectric semiconductor. Defects in semiconductors can be divided into four different types depending on their geometric dimensions, and thus understanding the effects on thermoelectric properties of each type is of a vital importance. This paper reviews the recent advances in the various thermoelectric semiconductors through defect engineering focusing on the charge carrier and phonon behaviors. First, we clarify and summarize each type of defects in thermoelectric semiconductors. Then, we review the recent achievements in thermoelectric properties by applying defect engineering when introducing defects into semiconductor lattices. This paper ends with a brief discussion on the challenges and future directions of defect engineering in the thermoelectric field.

• 임산에너지
• /
• 제23권2호
• /
• pp.9-20
• /
• 2004

중국 내몽골자치구 Dengkou 지역 내 양묘장과 방풍림에 신강포플러(Populus alba var. pyramidalis)를 식재하고, 시비 및 보습제 처리를 한 다음 6개월이 경과한 후 생장을 조사하고, 토양과 엽 내 질소와 인의 농도를 측정하였다. 토양 수분함량 (중량 $\%$)은 양묘장과 방풍림에서 일반 사막화지에 비하여 $10\%$ 정도 높았다. 묘포장과 방풍림의 신강포플러는 전반적으로 질소 (N) 처리구 및 질소+인 (N+P) 처리구가 다른 처리구에 비해 수고 및 근원직경 생장이 좋은 것으로 나타났다. 또한 양분 농도에서는 N+P 처리구와 N 처리구에서 전질소 농도가 가장 높은 것으로 나타났다. 인 농도는 시비 처리구간 차이가 없었으나, 묘포장의 경우 오히려 무처리구가 다른 처리구보다 높게 나타났다. Yuho 처리구에서는 다른 처리구보다 전질소와 인의 농도는 높게 나타나지 않았으나, 신강포플러 생장은 촉진시켰다. 초기 신강포플러 생장에 가장 큰 영향을 주는 성분이 질소인 것으로 나타났으며, 인은 생장에 큰 영향을 미치지 못하였다. 그러나 본 연구는 시비 및 토양 처리 후 당년에 조사한 결과이므로 이러한 처리가 신강포플러의 생장 및 양분 농도에 미치는 영향을 보다 더 장기적으로 지속할 필요가 있는 것으로 판단된다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
• /
• pp.236.1-236.1
• /
• 2010

Due to global warming, the need to secure an alternative resource has become more important nationally. Due to the high tidal range of up to 9.7m on the west coast of Korea, numerous tidal current projects are being planned and constructed. The rotor, which initially converts the energy, is a very important component because it affects the efficiency of the entire system, and its performance is determined by various design variables. In this paper, a design guideline of current generating HAT rotor and acceptable field rotor in offshore environment is proposed. To design HAT rotor model, wind mill rotor design principles and turbine theories were applied based on a field HAT rotor experimental data. To verify the compatibility of the rotor design method and to analyze the properties of design factors, 3D CFD model was designed and analysed by ANSYS CFX. The analysis results and findings are summarized in the paper.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2011년도 추계학술대회 초록집
• /
• pp.159.1-159.1
• /
• 2011

Due to the global warming, the need to secure the alternative resources has become more important worldwide. Having very strong current on the west coast with up to 10 m tidal range, there are many suitable sites for the application of TCP(Tidal current power) in Korea. Not only from the current produced from the high tidal range, but also it can be widely applied to the offshore jetties and piers. The VAT(Vertical axis turbine) system could be very effective tidal device to extract the energies from the attacking flow to the structures. For the relatively slow current speed, the VAT system could be more effective application than HAT(Horizontal axis turbine) device. The performance of VAT can be evaluated by various parameters including number of blades, shape, sectional size, diameters and etc. The paper introduces the multi-layer vertical axis tidal current power system with savonius turbine. The turbine was designed with consideration of optimal blade numbers and the performance was simulated by CFD analysis.

• 한국자동차공학회논문집
• /
• 제24권6호
• /
• pp.730-736
• /
• 2016

Recent research suggests the various applications of Model Predictive Control on vehicle systems. In numerous cases, nonlinear tire models such as the Magic Formula, which are highly complex and are more detailed than necessary, are used. This paper presents a nonlinear tire model that excludes the region of negative slope but expresses the nonlinear properties of tire well enough for tracking the lane of a racing course. The proposed inverse tire model can also be used to calculate the slip angle from the tire force. Thus, the model can be utilized to design the Model Predictive Controller.

• Nuclear Engineering and Technology
• /
• 제54권8호
• /
• pp.3043-3050
• /
• 2022

In Korea, all nuclear power plants (NPPs) participate in annual performance tests including in vivo measurements using the FastScan, a stand type whole body counter (WBC), manufactured by Canberra. In 2018, all Korean NPPs satisfied the testing criterion, the root mean square error (RMSE) ≤ 0.25, for the whole body configuration, but three NPPs which participated in an additional lung configuration test in the fission and activation product category did not meet the criterion. Due to the low resolution of the FastScan NaI(Tl) detectors, the conventional peak analysis (PA) method of the FastScan did not show sufficient performance to meet the criterion in the presence of interfering radioisotopes (RIs), ¹³⁴Cs and ¹³⁷Cs. In this study, we developed an artificial neural network (ANN) to improve the performance of the FastScan in the lung configuration. All of the RMSE values derived by the ANN satisfied the criterion, even though the photopeaks of ¹³⁴Cs and ¹³⁷Cs interfered with those of the analytes or the analyte photopeaks were located in a low-energy region below 300 keV. Since the ANN performed better than the PA method, it would be expected to be a promising approach to improve the accuracy and precision of in vivo FastScan measurement for the lung configuration.

• Natural Product Sciences
• /
• 제29권2호
• /
• pp.59-66
• /
• 2023

The anti-melanogenic activity of 259 actinomycete strains was tested, and based on the results for the inhibition of mushroom tyrosinase activity and the reduction in melanin content, Micromonospora sp. JCS1 and JCS7 were selected as the strains with the highest anti-melanogenic potential. The activity-guided fractionation of extracts from JCS1 and JCS7 led to the isolation of the dipeptides cyclo(ʟ-Phenyl alanine (Phe)-ʟ-Proline (Pro)) (1) and cyclo(ʟ-Tryptophan (Trp)-ʟ-Proline (Pro)) (2). These two compounds were tested for their inhibition of mushroom tyrosinase by monitoring ʟ-DOPA levels and melanin production. Cyclo(ʟ-Phe-ʟ-Pro) (1) and cyclo(ʟ-Trp-ʟ-Pro) (2) were thus confirmed to have the potential for use in functional whitening cosmetics containing actinomycete-derived secondary metabolites.

• 한국전기전자재료학회논문지
• /
• 제37권5호
• /
• pp.547-553
• /
• 2024

Precise control over the morphology of nanostructures is critical for tailoring their physical and chemical properties. This study addresses the challenge of developing a simple, integrated method for synthesizing both 1D and 2D colloidal Cu nanostructures in a single system, achieving successful tuning of their localized surface plasmon resonance (LSPR) properties. A facile hydrothermal synthesis utilizing potassium iodide (KI) and hexadecylamine (HDA) is presented for controlling Cu nanostructure morphologies. The key to achieving 1D nanowires (NWs) and 2D nanoplates (NPs) depends on the controlled adsorption of HDA molecules and iodide (I-) ions on specific crystal facets. Depending on the morphologies, the resultant Cu nanostructures exhibit tunable LSPR peaks from 558 nm [nanoplates (NPs)] to 590 nm [nanowires (NWs)]. These results pave the way for the scalable and cost-effective production of plasmonic Cu nanostructures with tunable optical properties, holding promise for applications in sensing, catalysis, and photonic devices.

• 대한화학회지
• /
• 제39권8호
• /
• pp.643-649
• /
• 1995

35$^{\circ}C$와 50$^{\circ}C$ 에서 치환(Z)-benzyl계와 치환(Y)-pyridine 그리고 N, N-dimethylaniline의 Menschutkin형 반응을 아세토니트릴에서 전기전도도법으로 측정하였다. 유사 1차 반응속도상수와 친핵체의 농도로부터 2차반응 속도상수를 계산하였다. $4-CH_3-$보다 전자 받게 치환기를 가진 benzyl bromide는 정상 $S_N2$ (직접 치환 2분자)반응속도만 관찰되었으나 3, $4-(CH_3/O)_2$-benzyl bromide와 $4-CH_3O$-benzyl bromide의 경우 밀착 이온쌍 중간체를 거치는 2분자 반응의 속도도 관측되었다.

• 대한기계학회논문집A
• /
• 제41권9호
• /
• pp.817-823
• /
• 2017

기존에는 연비를 고려한 적응형 순항 제어 알고리즘 개발과 연비 등의 성능을 고려한 적응형 순항 제어 시스템 개발 연구가 수행되었지만, 제어 파라미터를 포함한 차량 파라미터의 적응형 순항 제어에 대한 최적설계 연구는 미흡한 편이다. 이에 본 논문에서는 연비, 추종성, 승차감, 안전거리를 고려한 차량 및 제어 파라미터 최적설계를 수행하고자 한다. 이를 위해 차량 거동의 성능 측정 방법을 제안하고 적응형 순항 제어 시스템을 구축하였다. 그리고 성능에 주요한 영향을 미치는 차량 파라미터를 선별하여 이를 토대로 순차적 실험계획을 통해 크리깅 대체모델을 구축하였고, 연비를 최대화하며 목표 성능을 만족하는 크리깅 대체모델 기반 최적설계를 수행하였다.