• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1998년도 추계종합학술대회
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• pp.583-587
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• 1998

본 논문에서는 대형 탱커선의 의무 장비인 유배출 감시 장비 (Oil Discharge Monitoring Equipment)를 위한 유분 농도계의 설계에 대하여 연구하였다. ODME는 국제해사기구 (IMO)에서 일정 ton 이상의 대형 선박에 의무적으로 설치하도록 규정하고 있으며 이는 날로 심각해지는 해양 오염을 방지하는데 목적이 있다. ODME의 구성 요소는 중앙 제어 장치, 유분 농도계, 유량계, 선속계, Sampling System, 배출 제어 장치로 이루어져 있으며 이중 가장 중요한 것은 유분 농도계이다. 이는 선박에서 배출되는 물에 포함된 유 성분을 ppm 단위로 계측하는 것이다. 이를 위한 탁도 측정 방법에는 여러 가지가 있지만, 본 연구에서는 선박에서 사용이 용이한 광산란 방식과 방폭성을 가지는 광섬유를 이용하여 탁도를 측정하는 유분 농도계를 설계하였으며 아울러 이에 대한 탁도 계산 알고리즘에 대하여 고찰하였다. 측정의 정밀도는 0-999ppm 범위에서 $\pm$5%의 오차 이내로 측정이 가능함을 보였다. 이는 IMO의 규격 ($\pm$10%의 오차)에 만족하는 수치이다.

• 대한기계학회논문집B
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• 제21권11호
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• pp.1458-1465
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• 1997

This study investigated the effects of pressure on the growth of an impinging spray. We obtained the frozen images which were scattered by Nd ; YAG laser light (pulse width : 7 ns) using synchronization circuit made in the laboratory. For an impinging spray a growth of the penetration length was progressed with increase of the injection pressure but an ambient pressure restrained its growth. The effect of an ambient pressure on penetration was larger than that of an injection pressure. The pressure ratio had an effect on the penetration growth rate. The thickness growth rate depended on both the injection pressure and the ambient pressure compositively. A lower injection pressure or a higher ambient pressure was required for spatial distribution of impinging spray.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.1933-1938
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• 2014

Despite increasing importance of in vitro cell-based assays for the assessment of nanoparticles (NPs) cytotoxicity, their suitability for the assessment of NPs toxicity is still in doubt. Here, limitations of widely used cell viability assay protocol (i.e., MTT asssay) for the cytotoxicity assessment of P25 $TiO_2$ NPs were carefully examined and an alternative toxicity assessment method to overcome these limitations was proposed, where the artifacts caused by extracellularly formed formazan and light scattered by agglomerated NPs were minimized by measuring only the intracellular formazan via image cytometric methods.

• Journal of the Optical Society of Korea
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• 제13권2호
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• pp.261-266
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• 2009

The angular dispersion-type non-scanning Fabry-Perot was applied to an ethanol-water mixture in order to investigate its acoustic properties such as the sound velocity and the absorption coefficient. The scattered light from the mixture was analyzed by using the charge-coupled-device area detector, which made the measurement time much shorter than that obtained by using the conventional scanning tandem multi-pass Fabry-Perot interferometer. The sound velocity showed a deviation from ultrasonic sound velocities at low temperatures accompanied by the increase in the absorption coefficient, indicating acoustic dispersion due to the coupling between the acoustic waves and some relaxation process. Based on a simplified viscoelastic theory, the temperature dependence of the relaxation time was obtained. The addition of water molecules to ethanol reduced the relaxation time, consistent with dielectric measurements. The present study showed that the angular dispersion-type Fabry-Perot interferometer combined with an area detector could be a very powerful tool in the real-time monitoring of the acoustic properties of condensed matter.

• Journal of the Optical Society of Korea
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• 제13권2호
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• pp.272-278
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• 2009

Recently, there has been a growing interest in optical imaging of neural activity because the optical neuroimaging has considerable advantages over conventional imaging. Birefringence of the axon has been reported to change during neural activation, but the neurophysiological origin of the change is still unresolved. This study hypothesizes that the birefringence signal is at least partially attributed to the transient cellular volume change associated with nerve excitation. To examine this hypothesis, we investigated how the intensity of cross-polarized light transmitting through the axon would change as the size of the axon changes. For this purpose, a two-dimensional finite-difference time-domain program was developed with the improvement of the total-field/scattered-field method which reduces numerical noise. The results support our hypothesis in that the computed cross-polarized signals exhibit some agreement with previously-reported birefringence signals.

• 대한수의학회지
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• 제31권4호
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• pp.381-387
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• 1991

Deer hemal nodes were studied by gross anatomy and light microscopy. Hemal nodes were scattered in the periphery of thoracic and abdominal aortae, and spherical or avoid in shape. A hemal node consisted of a thin capsule and a hilum, and had numerous small subcapsular and deep sinuses distended by a great number of erythrocytes. Although a few lymphatic nodules and tissues were seen in the parenchyma, no typical cortex and medulla was defined. Blood vessels occurred, but lymph vessel was not observed in nodes. The parenchyma of the hemal node consisted of many erythrocytes and lymphocytes, and a few granulocytes, plasma cells megakaryocytes and macrophages. The stroma was composed of reticular cells and fibers. The capsule and trabecula was a collagenous connective tissue with smooth myofibers. The above findings suggest that the hemal nodes are involved in blood storage, blood filtration and immune reaction.

• 한국정밀공학회지
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• 제25권4호
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• pp.53-60
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• 2008

Electron detectors used in scanning electron microscope accept electrons emitted from the specimen and convert them to an electrical signal that, after amplification, is used to modulate the gray-level intensities on a cathode ray tube, producing an image of the specimen. Electron detector is one of the key components dominating the performance of scanning electron microscope so that the development of electron detectors having high performance is indispensable to acquire high quality images using scanning electron microscope. In this paper, we designed and manufactured an electron detector and conducted a couple of image capture experiments using it. In particular, scintillator which generates light photons when it is struck by high-energy electrons was manufactured and experimental studies on the optimization of manufacturing condition was carried out. From experiments to evaluate the performance of our detector, it was verified that the performance of our detector is equivalent to or better than that of the conventional one.

• 대한수의학회지
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• 제34권2호
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• pp.229-235
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• 1994

The hemal nodes of the Korean native cattle were studied by gross anatomy and light microscopy. Hemal nodes were spherical or ovoid in shape, and red or black in colors. A hemal node consisted of a thick capsule and a hilum, and had extensive subcapsular and deep sinuses distended by a great number of erythrocytes. Although a few lymphatic nodules and tissues were seen in the parenchyma, no typical cortex and medulla was defined. Blood vessels occurred, but lymph vessel was not observed in nodes. The stroma of the hemal node was composed of reticular cells and fibers. The parenchyma consisted of many erythrocytes and lymphocytes, and a few macrophages and megakaryocytes. The capsule and trabecula was a collagenous connective tissue with smooth muscle cells. B-lymphocytes were principally located in the lymphatic nodules of the hemal node. T-lymphocytes were scattered in the diffuse lymphatic tissues of the hemal node.

• 천문학회보
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• 제36권2호
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• pp.103.2-103.2
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• 2011

We measure the degree of polarization of the lunar regolith to map the distributions of the age and the particle size. We use a 12cm refracting telescope with a 2k-square pixel color CCD (R band) and a polarization filter. The angular resolution obtained is 3.02 km/pixel. Our goal is to obtain a map of the lunar particle size distribution on the lunar regolith and then that of the age distribution. Polarization of the light scattered by lunar surface contains information on their mean particle size. The mean particle size of the lunar surface has been decreased by continued micro-meteoroid impact over a long period. One can estimate the age of the lunar surface if the mean particle size is known. Particle sizes can be measured through observations of polarization because the mean particle size is related to the maximum polarization and albedo. The age and the particle size of the lunar regolith can give vital information for the future lunar exploration.

• 천문학회보
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• 제36권2호
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• pp.71.1-71.1
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• 2011

Significant discrepancies have been found between the dust masses of edge-on spiral galaxies derived from various tracers (optical/near-infrared, far-infrared/sub-millimeter observations, and the variation of dust attenuation with viewing angle). Here we report the first detection of a vertically extended far-ultraviolet (FUV) and near-UV (NUV) emission in an edge-on spiral galaxy NGC 891. The vertically extended emission is interpreted as the dust-scattered light due to a extraplanar dust layer in NGC 891 that contains about the same mass as the standard thin dust disk. This new dust component completely encloses the stellar disk and bulge, and solves the puzzle of dust mass.