• Journal of the Microelectronics and Packaging Society
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• v.4 no.2
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• pp.41-46
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• 1997

지향성이 좋고 에너지밀도가 높고 집광성이 뛰어난 Nd:YAG레이저를 이용해서 원거 리 레이저 조사를 통한 서미스터의 PTCR 특성을 관찰하여 원격 제어를 시도를하였다. 1064nm의 Nd:YAG레이저 광선을 BaTiO3 서미터 표면에 1m 거리에서 5mm2 빔 사이즈로 50~200mJ/pulse, 10Hz의 조건에서 조사하였을 때 서미스터의 전기저항변화는 약 103 정도 로 레이저 조사에 의하여 원격으로 PTCR 특성을 제어 할수 있었다.

• 전기의세계
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• v.42 no.3
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• pp.19-27
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• 1993

본고에서는 Nd:YAG 레이저의 구조 및 특성에 대하여 설명한 뒤 그 제작 및 응용기술에 대한 이해를 돕고자 한다. 제2장에서는 일반적으로 레이저에 대하여 잘 모르는 사람이 이해하기 쉽도록 발전원리에 대하여 간략하게 기술한 후, YAG 레이저의 구조 및 특징에 대하여 간략하게 기술하고 YAG레이저의 구조 및 특징에 대하여 설명하고자 한다. 제3장에서는 전기연구소에서 수행한 YAG 레이저의 설계 및 제작기술, 그리고 연구결과에 대하여 간략히 설명하고 제4장에서는 그 응용기술에 대하여 설명한다. 제5장은 본고에서 기술한 내용을 정리함과 동시에 금후의 발전방향에 대하여 이야기 하고자 한다.

• Nutrition Research and Practice
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• v.8 no.2
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• pp.177-182
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• 2014

BACKGROUND/OBJECTIVES: Irisin, a newly identified hormone, is associated with energy homeostasis. We investigated whether aged garlic extract (AGE) and exercise training intervention could improve body weight, insulin sensitivity, skeletal muscle fibronectin domain containing protein 5 (FNDC-5) levels, and plasma irisin in high-fat diet (HFD). MATERIALS/METHODS: Male Sprague Dawley rats were fed a ND (normal diet, n=5) or HFD (n=28) for 6 weeks. After 6 weeks, all rats were divided into 5 groups for the next 4 weeks: ND, (normal diet, n=5), HFD (high-fat diet, n=7), HFDA (high-fat diet + aged garlic extract, n=7), HFDE (high-fat diet + exercise, n=7), and HFDEA (high-fat diet + exercise + aged garlic extract, n=7). Exercise groups performed treadmill exercises for 15-60 min, 5 days/week, and AGE groups received AGE (2.86 g/kg, orally injected) for 4 weeks. RESULTS: Significant decreases in body weight were observed in the ND, HFDE, and HFDEA groups, as compared with the HFD group. Neither intervention affected the masses of the gastrocnemius muscle or liver. There were no significant differences in glucose levels across the groups. The homeostatic model assessments of insulin resistance were significantly higher in the HFD group, as compared with the ND, HFDA, HFDE, and HFDEA groups. However, skeletal muscle FNDC-5 levels and plasma irisin concentrations were unaffected by AGE or exercise in obese rats. AGE supplementation and exercise training did not affect skeletal muscle FNDC-5 or plasma irisin, which are associated with insulin sensitivity in obese rats. CONCLUSION: Our results suggest that the protection against HFD-induced increases in body fat/weight and insulin resistance that are provided by AGE supplementation and exercise training may not be mediated by the regulation of FNDC-5 or irisin.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.87.3-87.3
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• 2015

2015년 2월 27, 28일 양일 간, "Gemini 관측제안서 준비와 작성"이라는 주제로 $2^{nd}$ We Love Galaxies Meeting>을 개최하였습니다. "We Love Galaxies"는 외부은하를 연구하는 국내 대학원생들을 위해 마련한 학술 교류의 장입니다. 지난 2014년 7월에 열린 "제 1회 We Love Galaxies 대학원생 외부은하 워크샵"을 시작으로 매년 여름과 겨울에 정기적인 모임을 운영하고자 합니다. $2^{nd}$ We Love Galaxies Meeting>은 한국천문연구원 K-GMT Science Program의 도움을 받아 개최하였으며, 5명의 박사 연구원과 28명의 대학원생이 참가하였습니다. 성공적인 관측제안서 작성과 준비를 위해 Gemini 망원경의 기기 특성 및 관측제안서 작성 요령에 대한 강의와 더불어, 2015A Gemini 관측 프로그램에 대한 소개, 새로운 관측 아이디어에 대한 토론 등으로 프로그램을 진행하였습니다. 본 포스터를 통해 $2^{nd}$ We Love Galaxies Meeting>의 결과와 성과를 정리하고, 앞으로의 계획에 대해 소개하고자 합니다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.1-5
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• 1999

The rare-earth ions ($R^{3+}$, R=Nd, Er) doped $CaF_{2}$ layers have been grown on $CaF_{2}$ (111) substrate by molecular beam epitaxy. The surface structure and the crystallinity of $CaF_{2}:R^{3+}$ layers depending on the doping concentration of $R^{3+}$ and layer thickness were studied by reflection high-energy electron diffraction (RHEED). In aspect of application as buffer layer in semiconductor-related hybrid structure, the lattice displacement between $CaF_{2}:R^{3+}$ layers and $CaF_{2}$ (111) substrate was investigated by X-ray rocking curve analysis.

• The Journal of Internal Korean Medicine
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• v.21 no.5
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• pp.739-745
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• 2000

xWe studied about the causes of hypertension in the occidental and oriental medical records and the results are as follows. 1. The causes of hypertension in oriental medicine can be divided into wind, fire, phlegm and deficiency of Qi in our body, and broadly into three categories as emotions in excess, improper diet and damages of endogenous etiological factors. 2. Hypertension is the disease of undermining of fundamental aspects while prevailing incidental aspects and liver, heart and kidneys are the organs mainly related to hypertension. 3. The main pathological factors of hypertension are as follows; the disorder of Yin and Yang makes the situation of the deficiency of the vital essence of kidneys and the exuberance of the vital essence of liver and they are the fundamentals to be taken hypertension and finally make the state of the deficiency of both Yin and Yang. 4. In the point of occidental medical view, the essential hypertension is a disease of unknown etiology and we think it occurs not on the only one factor but on the various factors and secondary hypertension occurs from the diseases of the substances and the vessels of kidneys.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.11
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• pp.7-16
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• 2010

In this study, wire was used as the filler material for the laser repair welding, and the phenomenon in which the supplied filler material was melted and beaded down into the specimen was examined with varying laser powers and welding speeds. The optimal processing condition was found to be the laser power of 1,300 W, the welding speed and feed wire supply speed of 0.5 ml/in and the defocused distances of +2mm. At this time, the heat input(E) was $65{\sim}75\;J/mm^2$, and no internal defect occurred. When repair welding was carried out as the optimal processing for the part that had an external defect with the radius of 2mm, the filler metal was melted, resulting in the volume smaller than the defect part and thus causing the part unfilled. Therefore, it was found to be necessary to carry out repair welding two to three times by multiple passes rather than does it only once by single pass.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.6
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• pp.885-890
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• 2015

LLC resonant converter has been widely used because of its high efficiency and high energy density. In this paper, we designed a LLC resonant converter as the main power supply of the Nd:YAG pulse laser. First harmonic approximation (FHA) is used to model the LLC resonant converter. FHA equivalent circuit model and the transfer function of the LLC resonant converter is proposed. Soft start technology is also used to suppress the surge current. The laser output simulation test result is identical with the practical test, the laser energy of every pulse can reach up to 2.5J, and the pulse per second (PPS) can be adjusted from 6 to 18. The power system is verified stable and reliable by both of the simulation and experiment results.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1589-1596
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• 2015

A novel control method of a three-phase PWM inverter with LC filter is proposed. The transfer function of LC filter is the same as that of 2nd order low pass filter(2nd LPF) which has a zero damping ratio. A simple method of implementing 2nd LPF with damping ratio is to add resistor to inductor or capacitor of LC filter. In an industrial application, it is not practical to adopt damping resistor because it results in losses being proportional to square of current flowing through resistor. Instead of using damping resistors, the proposed active damping control(ADC) utilizes all pass filter(APF) and considers inherent processing delay of digital controller. The overall transfer function of the proposed method is the same as a 2nd LPF and its damping ratio is also controllable via control variables. Detailed design and implementation of controller is also presented. Experiments are conducted with a 7.5kVA induction motor drive system controlled by PWM converter and inverter. Test waveforms are also presented to verify the proposed LC filter control algorithm.

• Journal of Powder Materials
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• v.18 no.1
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• pp.24-28
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• 2011

Effect of Cu content on microstructural and magnetic properties of a $(Nd_{26.06},Dy_{6.51})Fe_{bal.}$ $Cu_xB_{0.97}$(wt.%), (x = 0.2, 0.3, 0.4, 0.5) strip-cast was studied. The average inter-lamellar spacing in the free surface and wheel side of the strip cast increased as the Cu content increases. The grain uniformity, the grain alignment, and (00L) texture of the strip cast increased with Cu contents up to 0.4 wt.%. These microstructural changes were attributed to the decrease of the effective cooling rate of the melted alloy caused by the decrease of the melting temperature of resulting from Cu addition. Coercivity and remanence were increased because of the grain alignment and (00L) texture improvement with Cu contents up to 0.4 wt.%.