• 한국전자파학회논문지
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• 제18권5호
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• pp.496-502
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• 2007

본 논문에서는 마이크로파 가열 시스템에서 가열을 위한 반응기로 사용되는 다중 모드 공동기 내부의 전계 분포를 균일하게 형성시키기 위한 슬롯 도파관 급전기를 설계, 제작하였다. 기존의 급전기 경우에는 다중 모드 공동기 내부의 전계를 균일하게 해주기 위해 모드 스터러나 턴테이블과 같은 추가적인 부품을 공동기 내부에 설치해 사용하였다. 제안된 슬롯 도파관 급전기는 자체적으로 균일한 방사를 갖도록 구형 도파관의 넓은 면에 4개의 슬롯이 있고 양쪽의 개구면이 단락된 구조를 특징으로 한다. 제안된 급전기가 장착된 다중 모드 공동기 내부의 전계 분포는 CST사의 MWS(Microwave Studio)를 이용하여 시뮬레이션 하였고, 기존의 급전기를 장착한 경우보다 더 균일한 전계 분포 특성을 보임을 확인하였다. 제작된 급전기는 사용 주파수 2.45 GHz에서 -20 dB 이하의 반사 손실을 보였다. 우리 제안의 타당성을 검증하기 위해, 공동기 내에 물 시료들을 배치해 일정시간 가열시켜 가열 전후의 온도 변화를 관찰하였다. 온도 변화는 공동기에 기존 급전기를 장착한 경우, 중앙과 가장 자리에 있는 시료들 사이에 약 $3.5^{\circ}C$, 제안된 급전기를 장착한 경우에는 약 $0.7^{\circ}C$의 차이를 보였다. 이를 통해, 제안된 급전기가 기존의 급전기보다 다중 모드 공동기 내의 전계 분포 균일성 향상에 기여함을 확인하였다.

• Journal of Radiation Protection and Research
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• 제35권1호
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• pp.26-33
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• 2010

비파괴검사 분야의 방사선 검사(RT) 방식은 image plate (IP)를 사용한 Computed Radiography(CR) 영상시스템의 도입에 따라 필름 방식의 아날로그 영상이 점차 디지털 영상으로 교체되고 있다. 비파괴검사에서 결함을 효과적으로 검출할 수 있는 영상의 품질은 촬영 조건, 영상획득매체, 사용 선원의 종류 및 촬영 거리, 검사체 두께등이 영향을 미친다. 본 논문에서는 비파괴 검사 분야에 적용할 수 있는 감마선원의 기본 특성을 조사하였고, FUJI사에서 개발한 CR 영상 시스템에 $^{75}Se$, $^{192}Ir$ 동위원소를 적용하여 영상을 획득하였다. 획득된 영상의 gray scale을 이미지 소프트웨어를 통해 추출한 후에 대조도 및 신호대잡음비를 계산하고 비교 분석하였다. 또한 투과도계를 이용한 비교 영상을 통하여 식별도를 분석하였다.

• Transactions on Electrical and Electronic Materials
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• 제7권5호
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• pp.240-246
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• 2006

The mathematical model of the power substation is proposed. The substation esteems as a set of the equipment elements which integrated common connections and electromagnetic field. Some capabilities of model represented by both electric networks and a discrete logical model demonstrated by non-directional graph. The model can be useful for solution of the problem of diagnostic of the high-voltage equipment.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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• pp.387-390
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• 2001

Thermopile thermometer can measure the temperature of an object without attaching the object. It measures the temperature by receiving the radiation energy from objects. The idea of this is from the law of Stefan-Boltzmann. In the past it was not used well because the size was big and the cost was too expensive. But, In these days it can be used many field because the size become smaller and advantage of cost by using micro machine technology. However, The accuracy of measuring is not better than electric type. So we want to improve the accuracy of sensor by analyzing the heat transfer of the thermopile. To analyze temperature distribution in the thermopile sensor, we use the FEM software which is named ANSYS. The conduction and radiation heat transfer is considered to simulate the temperature distribution and time response inside of the sensor.

• Journal of Radiation Protection and Research
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• 제20권3호
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• pp.187-200
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• 1995

본 연구는 극저주파대 전자기장(ELF)의 잠재적 건강위해를 문헌을 통해 고찰하였다. 최근의 연구는 주로 거주지 또는 직업적으로 전자기장에 노출된 사람의 암발생 및 출산결과 그리고 신경행동학적인 영향을 조사하기 위한 역학적 조사가 대부분이다. 또한, ELF의 생물학적 영향을 연구하기 위한 실험적 연구도 수행되고 있다. 현재까지의 연구결과를 보면 ELF가 암을 유발한다고 추정은 되지만 확정적으로 단정할 수 있는 증거가 부족하며 암 이외의 생물학적 영향도 추정은 되지만 암과의 연관성보다는 그 근거가 미약하다.

• 전자공학회논문지D
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• 제34D권4호
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• pp.47-53
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• 1997

We fabricated gamma radiation detector using high resistive p-Cd$_{80}$Zn$_{20}$Te grown by high pressure bridgman method and forming au thin film electrode by chemically electroless deposition method. The device of Au/Cd$_{80}$Zn$_{20}$Te/Au is a typical MIM structure. The characteristic of current-voltage showed good linearity to 3kV/cm but it depend on the square of electric field over 3kV/cm. As the results of rutherford backscattering spectroscope(RBS) and auger spectroscope on the Au/Cd$_{80}$Zn$_{20}$Te, Au penetrated to the surface of Cd$_{80}$Zn$_{20}$Te detector absorbed slightly high energy radiation like a few hundred keV and showed good performance to detect low energy gamma ray.mma ray.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.186-192
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• 2015

Background: Various solar energy collecting systems have been developed and analyzed for agricultural applications. They include solar thermal and electric devices such as solar crop dryers, solar water pumps, solar greenhouse heating, ventilation for livestock, solar aeration pumps, solar electricity, and many more. Purpose: This review provides the current status of research and development in the field as well as the solar energy systems that are currently in use in the agriculture sector across the globe. Review: Solar energy is the largest and cheapest energy resource on earth; one hour of solar radiation exceeds the complete global energy consumption in one year. The potential annual total solar radiation in South Korea is $3.58-5.4 kWh/m^2/day$. The available solar energy is sufficient for agricultural applications across the entire country. Conclusion: The scope of solar energy utilization in agricultural machinery engineering in South Korea and in other countries is promising.

• 한국통신학회논문지
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• 제22권7호
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• pp.1459-1467
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• 1997

The current on the thin planar structure as an element of the transversely fed electromagnetically coupled(EMC) microstrip dipole array antenna is obtained by using the integral forms of the finite difference time domain(FDTD) method. This method was applied to calculating the optimum current distribution (Doplh-Tchebyscheff distribution) of each dipole element on the feed line as a function of their offset positions for the narrow main beam width and the side beam level below -20 dB. The current on each dipole substitutes for the electric and magnetic current densities on the virtual surface of the FDTD calculation to express the far field intensity, the calculation time and the computer memeory can be reduced to about 80% and 1.3 Mbyte, respectively. The calculated radiation patterns are compared to the measured values and these are in good agreement.

• The Korean Journal of Ceramics
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• 제6권3호
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• pp.206-208
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• 2000

0.65 mol% MgO-doped LiNbO$_3$single crystals were grown by CZ method. The obtained single crystals were colorless and transparent. Noncritically phase-matched second harmonic generation (SHG) of 532-nm radiation from 1064-nm in MgO-doped LiNbO$_3$has been investigated by using pulsed Nd:YAG laser. The phase-matching temperature was room temperature. SHG conversion efficiencies were typically achieved higher than 50% at the phase-matching temperature with no photorefractive damage in the region of fundamental power density which was used in this experiment. The thermo-birefringence coefficient and the electro-birefringence coefficient of SHG were calculated from the temperature phase-matching profile with the electric field.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.373-377
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• 2016

Background: Experiments with small electrochemical apparatus were previously carried out for detecting low-energy neutrinos under irradiation of reactor neutrinos and under natural neutrino environment. The experimental result indicated that the output current of reactor-neutrino irradiated detector was appreciably larger than that of natural environmental one. Usual interaction cross-sections of neutrinos are quite small, so that they do not explain the experimental result at all. Materials and Methods: To understand the experimental data, we propose that some biological products may generate AV-type scalar field B0, leading to a large interaction cross-section. The output current generation is ascribed to an electrochemical process that may be assisted by weak interaction phenomena. Dissolved oxygen concentrations in the detector solution were measured in this study, for the purpose of understanding the mechanism of the detector output current generation. Results and Discussion: It was found that the time evolution of experimental output current was mostly reproduced in simulation calculation on the basis of the measured dissolved oxygen concentration. Conclusion: We mostly explained the variation of experimental data by using the electrochemical half-cell analysis model based on the DO concentration that is consistent to the experiment.