• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2006년도 제33회 추계학술대회 발표논문집
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• pp.73-73
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• 2006

• 천문학회보
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• 제38권1호
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• pp.72.1-72.1
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• 2013

Camera for QUasars in EArly uNiverse (CQUEAN) is an optical CCD camera, developed by Center for Exploration of Origin of the Universe (CEOU), which is now searching for high red shift quasar candidates. It has been operated since 2010, attached to the 2.1m Otto Struve telescope at the McDonald Observatory, USA. Based on the previous operation experiences, we present CQUEAN II system design which has a new filter wheel allowing with 20 narrow band filters. In addition, the auto guiding system will be rearranged and the interfacing units between the telescope and the instrument will become stabilized.

• 한국진공학회지
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• 제19권2호
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• pp.141-147
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• 2010

$Al_2O_3$, $TiO_2$, $HfO_2$와 같은 high-k (고 유전상수) 산화물 박막을 Si, $SiO_2$/Si, GaAs 기판에 각각 입혀서 주기적인 온도변화에 의해 발생되는 박막 표면에서의 반사율 변화를 이용한 열-반사율법을 이용하여 열전도도를 측정하였다. 그 결과, 약 50nm 두께에서 0.80~1.29 W/(mK)와 같은 높은 열전도도를 가지고 있어 CMOS와 메모리 디바이스와 같은 전자 회로에서 발생되는 열을 효과적으로 방산할 수 있고, 또 미세 입자의 크기에 따라 열전달이 변화하는 것을 확인하였다.

• 한국과학교육학회지
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• 제6권2호
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• pp.83-89
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• 1986

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2001년도 High Temperature Superconductivity Vol.XI
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• pp.14-14
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• 2001

• Journal of Radiation Protection and Research
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• 제45권3호
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• pp.95-100
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• 2020

Background: Compared with reported data of radon concentration, data of radon progeny concentration is limited in general, especially in outdoor environment. Materials and Methods: To know both the level and the variation of radon progeny concentration in outdoor environment in Beijing area, one-year continuous measurement with a cycle of 60 minutes was carried out by a step-advanced filter (SAF) monitor for radon progeny measurement. The observation site was located in a park in Eastern Beijing area, and the observation period was from October 17, 2018 to September 29, 2019. Results and Discussion: The equivalent equilibrium concentration (EEC) of radon progeny varies from 0.7 to 19.1 Bq·m^-3, with an annual average of 4.9 ± 2.7 Bq·m^-3. A clear diurnal variation of EEC, higher in the early morning and lower in the late afternoon, is observed due to the high sensitivity of the SAF monitor. Conclusion: Vertical convection of atmospheric boundary layer is thought to be the main reason of this phenomenon. For annual variation, the lowest monthly average EEC appeared in April, while the highest appeared in November, which might attribute to the atmospheric stability in different seasons.

• 시스템엔지니어링학술지
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• 제19권2호
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• pp.46-58
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• 2023

Deterministic safety analysis is a crucial part of safety assessment, particularly when it comes to demonstrating the safety of nuclear power plant designs. The traditional approach to deterministic safety analysis models is to model the nuclear core using point kinetics. However, this simplified approach does not fully reflect the real core behavior with proper moderator and fuel reactivity feedbacks during the transient. The use of Multi-Physics approach allows more precise simulation reflecting the inherent three-dimensionality (3D) of the problem by representing the detailed 3D core, with instantaneous updates of feedback mechanisms due to changes of important reactivity parameters like fuel temperature coefficient (FTC) and moderator temperature coefficient (MTC). This paper addresses a CEA ejection accident at hot full power (HFP), in which the underlying strong and un-symmetric feedback between thermal-hydraulics and reactor kinetics exist. For this purpose, a multi-physics analysis tool has been selected with the nodal kinetics code, 3DKIN, implicitly coupled to the thermal-hydraulic code, RELAP5, for real-time communication and data exchange. This coupled approach enables high fidelity three-dimensional simulation and is therefore especially relevant to reactivity initiated accident (RIA) scenarios and power distribution anomalies with strong feedback mechanisms and/or un-symmetrical characteristics as in the CEA ejection accident. The Systems Engineering approach is employed to provide guidance in developing the work in a systematic and efficient fashion.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.839-842
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• 2004

We present a fast-switching electro-optical device based on flexoelectro-optic effect in short pitch cholesterics oriented in uniform lying helix texture. The device has two operating modes: amplitude and phase modulation mode. The amplitude modulation mode is a fast in-plane switching of the device optic axis that enables to achieve a high percent of modulation of the transmitted light intensity whereas the phase mode gives a continuous change of the refractive index and thus of the phase shift of the transmitted light. By using a small concentration of diacrylate monomer and selecting the illumination conditions we have been able to create a inhomogeneous polymeric network mostly localized at both substrate surfaces and stabilize the two switching modes.

• 한국과학교육학회지
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• 제14권3호
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• pp.330-343
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• 1994

The purpose of this study was to investigate into common science and Science-Technology-Society education movement which are concerned in newly reformed 6th curriculum. These data were obtained by the survey of 291 high school science teachers who have no experience for the workshop of the common science in Kwangju city and 120 high school science teachers who have experience for the workshop of the common science in Kwangju city and Chollanamdo. The results were as follows: 1) They responded that the physics is more closely subject for the common science and thereby it could be charged for the common science by teacher of physics. 2) The 96.90 percent of the respondents (B-group) have confidence with teaching common science subject. 3) They favored that a device for the application of STS Thoughts is added last part of each chapter, last chapter or adequately introduce to each teaching. 4) They are not concerned about overlap with the contents of common science and each science contents (A-group:74.58 percent, B-group:78.35 percent). 5) They wondered about the various items of teaching and the lack of scientific surrounding Knowledge for solving problems. 6) They responded that if the common science are implicated into the current high school, the sciences will become a interesting. 7) Before the common science have become established, they was demanded a improvement of currently University Entrance Examination systems.

• 한국과학교육학회지
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• 제24권3호
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• pp.612-620
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• 2004

본 연구에서는 중 고등학생들의 전기 회로도에 관한 표상을 조사하기 위해 중학생 10명과 고등학생 10명을 대상으로 하였다. 저항 연결에 대해 중 고등학생들이 가지고 있는 전기 회로도의 원형과 저항 연결을 기술하는 유형, 등가 회로도를 분류할 때 사용하는 준거를 조사하였다. 중 고등학생들이 생각하는 전기 회로도의 원형은 직렬 연결은 저항 두 개가 일렬로 배열된 형태이며, 병렬 연결은 두 개의 저항이 고리모양을 하고 있거나 평행하게 배열된 형태였다. 세 개의 저항이 혼합 연결된 회로도는 직렬과 병렬 회로도 원형이 결합된 형태로 나타났다. 저항의 연결을 기술하는 유형은 저항 하나로도 직렬과 병렬 연결이 가능하며, 저항이 일렬로 되어 있으면 직렬, 저항이 평행하면 병렬로 기술하였다. 또한 전지와 저항을 포함하는 사각형태는 직렬로, 그 사각형을 가르는 선 위의 저항 또는 덧붙은 사각형 위에 있는 저항은 병렬로 기술하였다. 등가 회로도 분류 시 사용한 준거는 회로의 기하학적인 형태에 의존하는 경향을 보였다. 학생들은 전지나 저항의 위치, 전선의 형태를 고려하지 못했고, 전기 회로도의 원형에 영향을 받아 물리적 원리와는 관계없이 표상하였다. 따라서 다양한 등가 회로도를 제시하여 학생들이 직렬, 병렬 연결에 대해 가지고 있는 생각을 드러나게 하고 이를 교정할 필요가 있으며, 이러한 과정을 통해 전기 회로도에 관한 문제 해결 시 직렬과 병렬 연결에 대한 개념을 올바르게 적용할 수 있을 것이다.