• 천문학회지
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• 제50권5호
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• pp.139-149
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• 2017

The Korea Astronomy and Space Science Institute plans to develop a coronagraph in collaboration with National Aeronautics and Space Administration (NASA) and to install it on the International Space Station (ISS). The coronagraph is an externally occulted one-stage coronagraph with a field of view from 3 to 15 solar radii. The observation wavelength is approximately 400 nm, where strong Fraunhofer absorption lines from the photosphere experience thermal broadening and Doppler shift through scattering by coronal electrons. Photometric filter observations around this band enable the estimation of 2D electron temperature and electron velocity distribution in the corona. Together with a high time cadence (<12 min) of corona images used to determine the geometric and kinematic parameters of coronal mass ejections, the coronagraph will yield the spatial distribution of electron density by measuring the polarized brightness. For the purpose of technical demonstration, we intend to observe the total solar eclipse in August 2017 with the filter system and to perform a stratospheric balloon experiment in 2019 with the engineering model of the coronagraph. The coronagraph is planned to be installed on the ISS in 2021 for addressing a number of questions (e.g., coronal heating and solar wind acceleration) that are both fundamental and practically important in the physics of the solar corona and of the heliosphere.

• 항공우주기술
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• 제10권2호
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• pp.29-36
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• 2011

과학기술위성 3호는 우리별 위성 시리즈와 과학기술위성 1호, 2호를 잇는 소형위성으로 첨단 위성체 핵심 기술 선행연구, 첨단 우주 및 지구 과학 탑재체 개발, 우주분야 인력 양성 등의 다양한 역할을 수행한다. 과학기술위성의 주탑재체는 다목적 적외선 영상시스템으로 우리은하와 황도극지방을 관측하여 우주의 기원을 연구한다. 다목적 적외선 영상시스템에는 국산 적외선 센서의 우주검증을 위해 지표면의 적외선 영상 획득 임무도 추가되었다. 부탑재체는 초소형 영상 분광기로서 농작물의 작황, 댐의 수질 예측 모델, 에어로졸 광학 두께 측정 연구 등에 활용된다. 본 논문에서는 2012년 말에 발사되어 주어진 임무기간 동안 과학기술위성 3호의 다양한 임무 수행을 위한 운영개념을 설명한다.

• Journal of Magnetics
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• 제21권2호
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• pp.266-272
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• 2016

Transcranial magnetic stimulation devices has been used mainly for diagnostic purposes by measuring the functions of the nervous system rather than for treatment purposes, and has a problem of considerable energy fluctuations per repeated pulse. The majority of strokes are caused by ischemia and result in brain tissue damage, leading to problems of the central nervous system including hemiparesis, dysfunction of language and consciousness, and dysfunction of perception. Control is difficult and the size is large due to the difficulty of digitalizing the energy stored in a capacitor, and there are many heavy devices. In addition, there are many constraints when it is used for a range of purposes such as head and neck diagnosis, treatment and rehabilitation of nerve palsy, muscle strengthening, treatment of urinary incontinence etc. Output stabilization and minimization of the energy variation rate are required as the level of the transcranial magnetic stimulation device is dramatically improved and the demand for therapeutic purposes increases. This study developed a compact, low cost transcranial magnetic stimulation device with minimal energy variation of a high repeated pulse and output stabilization using a real time capacitor charge discharge voltage. Ischemia was induced in male SD rats by closing off the common carotid artery for 5 minutes, after which the blood was re-perfused. In the cerebrum, the number of PARP reactive cells after 24 hours significantly decreased (p < 0.05) in the TMS group compared to the GI group. As a result, TMS showed the greatest effect on necrosis-related PARP immuno-reactive cells 24 hours after ischemia, indicating necrosis inhibition, blocking of neural cell death, and protection of neural cells.

• 한국재료학회지
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• 제12권1호
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• pp.58-67
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• 2002

In this study copper chloride(CuCl$_2$) solution was used as raw material to produce the fine copper oxide powder which has less than 1 $\mu\textrm{m}$ average particle size and has uniform particle size distribution by spray pyrolysis process. In the present study, the effects of reaction temperature, the injection speed of solution and air, the nozzle tip size and the concentration of raw material solution on the properties of produced powder were studied. The structure of the powder became much more compact with increasing the reaction temperature regardless of copper concentration of the raw material solution. The particle size of the powder increased accordingly with increasing the reaction temperature in case of 30 g/$\ell$ copper concentration of the solution. The particle size of the powder increased accordingly, and the surface structure of the powder became more porous with increasing the copper concentration of the raw material solution. When copper concentration in raw material solution was more than 100 g/$\ell$, all produced powder was CuCl regardless of reaction temperatures. When copper concentration in solution was below 30 g/$\ell$ and reaction temperature was higher than 90$0^{\circ}C$, CuO was the main phase. The surface of the powder tended to become porous with increasing the injection speed of solution. Particle size was increased and the surface of the powder showed severely disrupted state with increasing the nozzle tip size. The particle size was decreased and the particle size distribution was more uniform with increasing the air pressure through the nozzle.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.192-196
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• 1996

[ $1.06/1.32{\mu}m$ ] dual-wavelength medical laser was developed and preliminary clinical comparisons at these two wavelengths were performed for dental application. We could develop a compact laser system 1) by lasing two wavelengths from the same Nd:YAG rod, and 2) by introducing high-voltage switching power supply modules. Experiment on gingiva of pig jaw showed higher thermal damage at $1.32{\mu}m$. Depending on particular procedures, each wavelength has its own advantages and disadvantages. For cutting, however, using conical tips rather than bare fibers provided better results with low threshold of cutting energy and less surrounding thermal damage. Appling light-absorbing dye on target area appeared to induce more damage during laser irradiation. However, histological studies showed no significant difference whether dye was applied or not.

• 식물조직배양학회지
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• 제22권4호
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• pp.189-194
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• 1995

유자의 배배양에 의한 캘러스의 유도는 미숙열매의 배로부터 가장 양호하게 유기되었다. 이들 캘러스는 3% sucrose 와 44.4 $\mu$M BA가 첨가된 1/2 MS배지에 치상하였을 때 가장 잘 유도되었으며 배양조건은 26$^{\circ}C$ 에서 2000 lx로 16 h의 광주기와 8 h의 암주기로 배양하였다. 이들 캘러스는 담황색으로 표면에 크고 작은 많은 돌기들을 가지고 있는 캘러스와 암갈색의 캘러스가 관찰되었다. 또한 캘러스 발달 단계와 기관분화의 정도에 따라서 세포배열 양상에 많은 차이가 있었는데, 배양 6주된 캘러스는 작은 세포들이 조밀하게 나타났으며 8주경부터 신장된 세포들이 분열하는 양상을 보여 주었으며 주된 캘러스 표면의 돌기들은 기관 발생의 초기에 구형의 세포돌기가 융기된 반면 주변의 세포들 은 액포화된 것으로 나타났다. 배양 16주 후에, 재분화된 shoot는 MS 배지에 이식하였을 때 발근이 되어 정상적으로 생장하였다. Shoo떼서는 유관속 형성층과 정유를 함유하고 있는 유낭의 초기 발생과정이 광학현미경으로 관찰되었다. 형성된 shoot를 화분에 이식하였을때 정상적으로 생장이 계속되는 것을 관찰하였다.

• 대한핵의학회지
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• 제39권1호
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• pp.1-8
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• 2005

상용 PET사이클로트론의 기술적인 변화는 PET의 수요와 밀접한 관계가 있다. PET활용이 일반화 되어 미국을 중심으로 PET의 수요가 급증하게 됨에 따라 사이클로트론의 수요도 증가 하였다. 기존의 사이클로트론은 크기와 무게로 병원에 설치에 공간과 전원 공급 등 여러 문제가 있어 각 사이클로트론 제작사들은 새로운 모델을 출시하게 되었다. 새로운 모델의 특징은 다음과 같다. 첫째 기존의 모델이 양성자와 중양자 등의 2가지 이온을 인출 하였으나 시스템의 복잡성 등의 문제와 양성자로 O-15 생산이 가능하여 양성자 빔만을 인출 하거나 중양자는 선택 사양으로 전환 하였다. 둘째 기존 모델의 경우 양성자의 빔 에너지는 약 16 MeV 이상 가속 시킬 수 있으나 신 모델은 13 MeV 이내로 대폭 낮추어 PET 용 Rl생산에 최적화하였다. 셋째 전자석, RF 장치등의 최적화를 이룩하여 전력소모를 대폭 개선하였으며 외양도 대폭 작아져 무게를 20톤 이내로 대폭 낮추었다. 넷째 새로운 모델 사이클로트론들은 자체 차폐기능이 일반화 되었으나 IBA제품이나 삼영유니텍 제품은 사용자의 견지에 따라 선택 사양이 가능하다.

• 화훼연구
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• 제16권4호
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• pp.304-308
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• 2008

분화용 나팔나리 'Nellie White', 'Ace' 및 'Hinomoto'와 교잡으로 자가 수정 5세대에서 선발한 계통인 L2-17'과 'L2-21'을 교잡하여 1대 교잡종 'Charm'을 육성하였다. 종자번식 나팔나리 일대잡종 품종 'Charm'은 화색이 흰색이고, 식물체 당 개화수가 7.4개로 많은 편이며, 꽃의 직경이 16.5 cm이고 개화기는 4월 10일경이다. 초장은 60.3 cm이고, 잎의 수는 70.3개이고, 잎의 길이는 18.8 cm이며, 잎의 폭은 2.4 cm이다. 또한 관상기간이 24.5일이고 기호도가 높다. 한편 'Charm'의 협당 채종 종자수는 251.1개이고, 발아율은 94.7%로 높다. 이와 같이 일대 잡종 'Charm'은 식물체 하부 잎이 건실하여 초세가 강건하고, 화경이 크고 화수가 많아서 개화기간이 길다. 또한 종자번식을 하므로 무병주 생산이 가능하다.

• 대한치과의사협회지
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• 제56권12호
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• pp.667-685
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• 2018

Objectives: Aim of this study was to evaluate bone regenerative efficacy of a chemically cross-linked porcine collagen membrane (CM) when used in combination with highly soluble biphasic calcium phosphate (BCP). Materials and methods: Physiochemical properties of the experimental collagen membrane were analyzed. Four circumferential defects with diameter of 8 mm were created in each calvarium of New Zealand white rabbits (n = 10). Defects were randomly allocated to one of following 4 groups: 1) BCP-CM (BCP (20% hydroxyapatite/80% ${\beta}$-tricalcium phosphate) covered with the prepared collagen membrane), 2) BCP (only BCP used), 3) CM (only the prepared collagen membrane used), and 4) C (control; only blood clot). After 2 weeks (n = 5) and 8 weeks (n = 5), histologic and histomorphometric analyses were performed. Results: The experimental collagen membrane exhibited dense and compact structure, relatively high tensile strength and lower degradability. Histologic analyses revealed that new bone increased rapidly at 2 weeks, while defect was preserved at 8 weeks. Histomorphometric analyses revealed that the new bone areas increased in the BCP-grafted groups over 8 weeks, with BCP-CM exhibiting greater total augmented area than that of BCP group both at 2 weeks ($27.12{\pm}3.99$ versus $21.97{\pm}2.27mm^2$) and 8 weeks ($25.75{\pm}1.82$ versus $22.48{\pm}1.10mm^2$) (P < 0.05). Conclusions: The experimental collagen membrane successfully preserved localized defect for 8 weeks despite early rapid resorption of BCP. Within the study limitations, combined use of the chemically cross-linked porcine collagen membrane and highly soluble BCP aided localized bone regeneration.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.228-237
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• 2019

The crack growth responses of as-received and as-welded Alloy 600/182 and Alloy 690/152 welds to constant loading were measured by a direct current potential drop method using compact tension specimens in primary water at $325^{\circ}C$ simulating the normal operating conditions of a nuclear power plant. The as-received Alloy 600 showed crack growth rates (CGRs) between $9.6{\times}10^{-9}mm/s$ and $3.8{\times}10^{-8}mm/s$, and the as-welded Alloy 182 had CGRs between $7.9{\times}10^{-8}mm/s$ and $7.5{\times}10^{-7}mm/s$ within the range of the applied loadings. These results indicate that Alloys 600 and 182 are susceptible to cracking. The average CGR of the as-welded Alloy 152 was found to be $2.8{\times}10^{-9}mm/s$. Therefore, Alloy 152 was proven to be highly resistant to cracking. The as-received Alloy 690 showed no crack growth even with an inhomogeneous banded microstructure. The cracking mode of Alloys 600 and 182 was an intergranular cracking; however, Alloy 152 was revealed to have a mixed (intergranular + transgranular) cracking mode. It appears that the Cr concentration and the microstructural features significantly affect the cracking resistance and the cracking behavior of Ni-base alloys in PWR primary water.