• 한국구조물진단유지관리공학회 논문집
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• 제17권4호
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• pp.112-118
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• 2013

성능기반 내진설계 및 평가의 정밀도 향상에 있어서 적절한 지반운동 데이터 선정과 이를 합리적으로 수정하는 것에 대한 중요성이 부각되고 있다. 지반운동 데이터를 수정하는 방법으로 단일 진폭수정법 (Amplitude scaling)이 널리 사용되고 있으나, 단일 진폭수정법에서 는 단 하나의 주기, 특히 구조물의 고유주기에서만 그 응답스펙트럼 값이 설계스펙트럼의 값과 일치하도록 수정되므로 특정 지역의 지진 재해도에 대해 일관성 있는 구조 해석 결과를 기대하기 어렵다. 따라서 이에 대해 여러 가지 대안 수정법들이 제시되고 있으나 이들의 타당성을 평가할 수 있는 방안이 마련되어 있지 않다. 본 논문에서는 단일 진폭수정법의 문제점을 설명하고, 대안 수정법과 비교 평가하기 위한 구조 응답에 대한 회귀 모델을 제시하는데 목표를 두었다. 대안 수정법으로써 전체 주기 범위에서 지반운동의 응답스펙트럼이 설계스펙트럼의 값과 일치하도록 수정하는 다중 스펙트럼 수정법을 고려하였다. 설계스펙트럼은 ASCE7-05에 따라 구하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.229-234
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• 2002

Under the hostile influence of the extreme space environmental conditions due to the deep space and direct solar flux, the thermal control in space applications is especially of major importance. There are tight temperature range restrictions for electro-optical elements while on the other hand there are low power consumption requirements due to the limited energy sources on the spacecraft. So, we usually have strong requirement of thermal and power control module in space applications. In this paper, the design concept of a thermal and power control module in the MSC(Multi-Spectral Camera) system which will be a payload on KOMPSATII is described in terms of H/W & S/W. This thermal and power control module, called THTM(Thermal and Telemetry Module) in MSC, resides inside the PMU(Payload Management Unit) which is responsible for the proper management of the MSC payload for controlling and monitoring the temperature insides the EOS(Electro-Optic System) and gathering all the analog telemetry from all the MSC sub-units, etc. Particularly, the designed heater controller has the special mode of "duty cycle" in addition to normal closed loop control mode as usual. THTM controls heaters in open loop according to on/off set time designed through analysis in duty cycle mode in case of all thermistor failure whereas it controls heaters by comparing the thermistor value to temperature based on closed loop in normal mode. And a designed THTM provides a checking and protection method against the failure in thermal control command using the test pulse in command itself.

• 한국광학회지
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• 제3권2호
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• pp.77-85
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• 1992

Varied-line spacing concave grating을 이용하여 결상면에서 거의 균일한 분해능을 갖는 평면결상 극자외선 분광기를 설계하엿다. 레이저-프라즈마에서 복사되는 발산광의 집속과 분광기의 수차보정을 위해 toroidal mirror를 사용하였고, 비축광선에 의한 수차를 줄이기 위해 toroidal mirror와 회절격자 사이에 10$\mu \textrm m \times2$mm크기의 입사슬릿을 두었다. 평면결상이 가능한 파장영역은 50~300$\AA$이고, 계산된 분해능은 4000이상이다. 회절격자의 효율과 toroidal mirror에서의 반사율을 고려하면 복사 에너지의 집속도는 toroidal mirror를 사용하지 않았을 때보다 3.5배 증가하고, fluorescence는 파장 100.angs.에서 1000배 이상 증가했다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.141-141
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• 2010

The effect of thermal anneal on the characteristics of structural properties and the enhancement of luminescence and photovoltaic (PV) characteristics of silicon-rich silicon-nitride films were investigated. By using an ultra high vacuum ion beam sputtering deposition, B-doped silicon-rich silicon-nitride (SRSN) thin films, with excess silicon content of 15 at. %, on P-doped (n-type) Si substrate was fabricated, sputtering a highly B doped Si wafer with a BN chip by N plasma. In order to examine the influence of thermal anneal, films were then annealed at different temperature up to $1100^{\circ}C$ under $N_2$ environment. Raman, X-ray diffraction, and X-ray photoemission spectroscopy did not show any reliable evidence of amorphous or crystalline Si clusters allowing us concluding that nearly no Si nano-cluster could be formed through the precipitation of excess Si from SRSN matrix during thermal anneal. Instead, results of Fourier transform infrared and X-ray photoemission spectroscopy clearly indicated that defective, amorphous Si-N matrix of films was changed to be well-ordered thanks to high temperature anneal. The measurement of spectral ellipsometry in UV-visible range was carried out and we found that the optical absorption edge of film was shifted to higher energy as the anneal temperature increased as the results of thermal anneal induced formation of $Si_3N_4$-like matrix. These are consistent with the observation that higher visible photoluminescence, which is likely due to the presence of Si-N bonds, from anneals at higher temperature. Based on these films, PV cells were fabricated by the formation of front/back metal electrodes. For all cells, typical I-V characteristic of p-n diode junction was observed. We also tried to measure PV properties using a solar-simulator and confirmed successful operation of PV devices. Carrier transport mechanism depending on anneal temperature and the implication of PV cells based on SRSN films were also discussed.

• Mycobiology
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• 제36권3호
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• pp.173-177
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• 2008

The crude ethanol extracts (stem and fruits), their fractions and two triterpenes, $\beta$-Amyrin and 12-Oleanene 3$\beta$, 21$\beta$-diol, isolated as a mixture from the chloroform soluble fraction of an ethanolic extract of Duranta repens stem, were evaluated for antibacterial, antifungal activities by the disc diffusion method and cytotoxicity by brine shrimp lethality bioassay. The structures of the two compounds were confirmed by IR, $^1H$-NMR, $^{13}C$-NMR and LC-MS spectral data. The chloroform soluble fraction of stem and ethanol extract of fruits possess potent antishigellosis activity and also exhibited moderate activity against some pathogenic bacteria and fungi but the isolated compound 1 (mixture of $\beta$-Amyrin and 12-Oleanene 3$\beta$, 21$\beta$-diol) showed mild to moderate inhibitory activity to microbial growth. The minimum inhibitory concentrations (MICs) of the extracts (stem and fruits), their fractions and compound 1 were found to be in the range of 32$\sim$128 ${\mu}g/ml$. The chloroform soluble fractions of stem and ethanol extract of fruit showed significant cytotoxicity with $LC_{50}$ value of 0.94 ${\mu}g/ml$ and 0.49 ${\mu}g/ml$, respectively against brine shrimp larvae.

• Journal of Photoscience
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• 제9권3호
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• pp.45-48
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• 2002

Microbial rhodopsins, photoactive 7-transmembrane helix proteins that use retinal as their chromophore, were observed initially in the Archaea and appeared to be restricted to extreme halophilic environments. Our understanding of the abundance and diversity of this family has been radically transformed by findings over the past three years. Genome sequencing of cultivated microbes as well as environmental genomics have unexpectedly revealed archaeal rhodopsin homologs in the other two domains of life as well, namely Bacteria and Eucarya. Organisms containing these homologs inhabit such diverse environments as salt flats, soil, freshwater, and surface and deep ocean waters, and they comprise a broad phylogenetic range of microbial life, including haloarchaea, proteobacteria, cyanobacteria, fungi, and algae. Analysis of the new microbial rhodopsins and their expression and structural and functional characterization reveal that they fulfill both ion transport and sensory functions in various organisms, and use a variety of signaling mechanisms. We have obtained the first crystallographic structure for a photosensory member of this family, the phototaxis receptor sensory rhodopsin II (SRII, also known as phoborhodopsin) that mediates blue-light avoidance by the haloarchaeon Natronobacterium pharaonis. The structure obtained from x-ray diffraction of 3D crystals prepared in a cubic lipid phase reveals key features responsible for its spectral tuning and its sensory function. The mechanism of SRII signaling fits a unified model for transport and signaling in this widespread family of phototransducers.

• Journal of Preventive Medicine and Public Health
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• 제39권2호
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• pp.165-170
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• 2006

Objectives : The determination of oxalate in urine is required for the diagnosis and treatment of primary hyperoxaluria, idiopathic stone disease and various intestinal diseases. We examined the possibility of using Fourier transform near-infrared (FT-NIR) spectroscopy analysis to quantitate urinary oxalate. The practical advantages of this method include ease of the sample preparation and operation technique, the absence of sample pre-treatments, rapid determination and noninvasiveness. Methods : The range of oxalate concentration in standard urine solutions was $0-221mg/{\ell}$. These 80 different samples were scanned in the region of 780-1,300 nm with a 0.5 nm data interval by a Spectrum One NTS FT-NIR spectrometer. PCR, PLSR and MLR regression models were used to calculate and evaluate the calibration equation. Results : The PCR and PLSR calibration models were obtained from the spectral data and they are exactly same. The standard error of estimation (SEE) and the % variance were $10.34mg/{\ell}$ and 97.86%, respectively. After full cross validation of this model, the standard error of estimation was $5,287mg/{\ell}$, which was much smaller than that of the pre-validation. Furthermore, the MCC (multiple correlation coefficient) was 0.998, which was compatible with the 0.923 or 0.999 obtained from the previous enzymatic methods. Conclusions : These results showed that FT-NIR spectroscopy can be used for rapid determination of the concentration of oxalate in human urine samples.

• 한국식품위생안전성학회지
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• 제17권3호
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• pp.117-123
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• 2002

시중에 유통되고 있는 녹차중의 catechin류에 대하여 열수추출 및 HPLC분석을 통하여 함량을 조사하고 이를 효율적으로 이용하기 위하여 pH조건이 녹차 catechin류의 안정성에 미치는 영향에 대하여 분석하였다. 시판 중인 전남 보성산 녹차의 catechin류 함량은 (+)-catechin>(-)-EGCg>(-)-EGC>(-)-EC>(-)-ECg순으로 추출되었고 Total catechin류의 함량은 103.72mg/g이었다. 녹차에서 분리·정제되어진 catechin류인 (+)-catechin, (-)-EC, (-)-ECg, (-)-EGCg를 pH 3∼11에 대한 안정성을 흡광도측정장치를 이용하여 측정하였다. 그 결과 catechin류의 pH에 대한 영향을 최대흡수파장 및 흡광도 변화로 보면 pH가 높을수록 (+)-catechin과 (-)-EC은 흡광도가 증가되었고 (-)-ECg와 (-)-EGCg는 최대흡수파장이 증가되었다. 또한 7일간 실온에서 저장하면서 기간에 따른 변화를 살펴본 결과에서 산성조건에서는 큰 변화가 없지만 알칼리조건에서는 흡광도가 증가되었다. (+)-catechin과 (-)-EC은 알칼리조건에서 흡수파장 400∼430 nm에서 저장기간이 길수록 흡광도가 증가되었다. 이는 녹차의 갈변과 관계가 있을 것으로 생각되었다. 이상의 결과로, 녹차 Catechin유도체의 pH 및 저장기간에 대한 영향은 ECg, EGCg에 gallic acid의 결합에 의한 것으로 생각되고, C, EC의 불안정은 중합반응으로 생각된다. 녹차 catechin류는 대부분 산성에서 저장기간이 길고 안정한 것으로 나타났으나 생리활성이 강한 (-)-EGCg는 산성에서도 불안정한 것으로 나타났다. 결론적으로 녹차의 기능성 성분을 효율적으로 이용하기 위해서는 pH를 낮게 유지하여야 할 것으로 사료되어진다.

• Annals of Clinical Neurophysiology
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• 제3권2호
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• pp.128-135
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• 2001

Background : Tremor is uncommon manifestation of stroke. Therefore a few cases have been reported until now. There is still uncertainty about the characteristics of post-stroke tremor. Furthermore the pathogenesis and responsible structures of post-stroke tremor are not precisely known. We have recently experienced 34 cases of post-stroke tremor for the past 6 years. We analysed the clinical features and electrophysiologic findings of post-stroke tremor to evaluate the general characteristics and to analogize the possible pathogenetic mechanisms of post-stroke tremor. Methods : The clinical characteristics of post-stroke tremor were summarized in according to the onset time, involved body parts, types, tremor frequencies, neuroradiologic findings, and associated symptoms. The tremor frequencies were recorded by using a gyroscope. The spectral analysis of tremor frequencies were done automatically with Motus I soft ware. Results : Tremor onset were remarkably varied. Some patients showed a tremor appearing at the onset of a stroke and other patients showed delayed-onset tremor 10 years after a stroke. Tremor frequencies were also much varied. The range of hand tremor frequencies were from 1.5 to 12 Hz. Lesions were found in 31 cases(infarction 27, hemorrhage 4) on neuroimaging. In the cases of cerebral infarctions, 7 cases showed multiple small vessel diseases and 20 cases showed cerebral vessel lesions. The most commonly involved cerebral vessel lesion was the middle cerebral artery territory Several different clinical patterns of post-stroke tremor were identified. Conclusions : There are some evidences from the data summarized here to suggest that several pathogenetic mechanisms including central oscillators could be involved for the development of tremors and that tremor generating neural circuits could be more complex than previously suggested neural circuits.

• 대한원격탐사학회지
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• 제24권6호
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• pp.631-639
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• 2008

본 연구에서는 상업용 위성에 탑재된 센서에서 감지된 고해상도의 범색 영상과 다중분광 영상을 이용하여 저해상도의 초분광 영상을 고해상도로 재구축하는 방법을 IKONOS영상과 30-1의 Hyperion 영상에 대한 적용을 통하여 제시하고 있다. 제안된 초분광 영상의 고해상도 재구축은 Lee(2008b)에 의해 개발된 FitPAN-Mod를 기반으로 하여 30m 급의 공간해상도의 초분광 영상을 1m 급의 공간해상도의 범색 영상 수준으로 공간해 상도를 향상시킨다. 본 연구에서는 세 번의 FitPAN-Mod를 사용하는 저해상도의 영상의 고해상도 재구축 과정을 걸쳐 범색 영상의 파장구간에 속하는 초분광 영상의 50개 밴드에 대해 재구축이 이루어졌다. 실험 결과는 재구축된 영상은 시각적 평가에서 실험 대상 지역 내 범색 영상이 갖고 있는 자세한 공간적 구조를 잘 표현하고 있으며 저해상도에서 세부적 위치에 따라 구분하여 표현할 수 없는 지표면의 좁은 밴드대역의 분광특성을 잘 표현하고 있음을 보여준다. 이러한 결과는 제안된 재구축 방법이 현재의 센서 기술로 수집할 수 없는 고해상도의 초분광 영상의 대체 영상을 생성할 수 있는 기술로서 잠재력을 갖고 있음을 보여준다.