• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.42-42
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• 2012

The First stars (Pop.III stars) in the universe are expected to be formed between the recombination era at z - 1100 and the most distant quasar (z - 8). They have never been directly detected due to its faintness so far, but can be observed as a background radiation at around 1${\mu}m$ which is called the Cosmic Near-Infrared Background (CNB). Main part of the CNB is thought to be redshifted Lyman-alpha from gas clouds surrounding the Pop.III stars. Until now, the COBE (COsmic Background Explorer) and the IRTS (Infrared Telescope in Space) observed excess emission over the background due to galaxies. To confirm the COBE and the IRTS results and pursue more observational evidences, we carried out the sounding rocket experiment named the Cosmic Infrared Background ExpeRiment (CIBER). The CIBER is successfully launched on July 10, 2010 at White Sands Missile Range, New Mexico, USA. It consists of three kinds of instruments. We report the results obtained by LRS (Low Resolution Spectrometer) which is developed to fill the uncovered spectrum around 1${\mu}m$. LRS is a refractive telescope of 5.5 cm aperture with spectral resolution of 20 - 30 and wavelength coverage of 0.7 to 2.0${\mu}m$. After subtracting foreground components (zodiacal light, integrated star light and diffuse galactic light) from the sky brightness of observed five fields, there remained significant residual emission (even for the lower limit case) consistent with the IRTS and the COBE results. In addition, there exists a clear gap at 0.7 - 0.8${\mu}m$ in the CNB spectrum over the background due to galaxies according to recent results (Matsuoka et al. 2011; Mattila et al. 2011). The origin of the excess emission could be ascribed to the Pop.III stars with its active era of z = 7 - 10.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.49.1-49.1
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• 2011

집광채광 설비는 건축물의 조명에너지 절감 및 자연광의 실내 유입을 위해 적용 가능한 태양에너지설비로써 다른 신 재생 에너지 설비와 다르게 연간에너지생산에 대한 정량적 데이터가 아직까지 부재하다. 집광채광 설비의 설치효과를 판단하기 위해서는 집광채광 설비 설치에 따른 연간 에너지생산량 산출이 필요하며, 이를 위해서는 각 구성부분(집광부, 전송부 및 산광부)의 광전송 효율에 대한 데이터가 구축되어야 한다. 본 연구는 집광채광 설비의 효율 분석에 관한 첫 번째 단계로써 외부광속에 대한 집광부 통과 직후의 내부광속의 비율을 예측하였다. 국내에 보급된 집광채광 설비는 대부분 프리즘형과 광덕트형이며, 우선적으로 집광부 입사면의 경사각과 방위각이 다양하여 내부광속 산출방법론이 매우 복잡한 프리즘형을 분석대상으로 삼았다. 전일사량, 외부조도 및 집광부 내부조도가 측정되었으며, 외부광속으로부터 내부광속을 산출하는 공식을 유도하기 위해 천공상태에 따라 전일사량 측정치가 직산분리 되었다. Perez model과 Liu and Jordon에 의해 제시된 계산식과 입사면 및 집광부 면적을 고려하여 수평면 외부조도 측정치로부터 외부광속이 그리고 내부조도로부터 내부광속이 산출되었다. 입사면의 투과율이 동일하다는 전제 하에 천공상태에 따른 태양광 투과 비율을 도출한 결과, 담천공(Kt ${\leq}$ 0.3)에서 0.39, 부분담천공(0.3${\geq}$ 0.78)에서 1.0으로 나타났다. 도출된 투과비율을 외부광속에 적용하여 내부광속을 계산한 결과치와 측정치는 약 ${\pm}9%$ 정도의 차이를 보였다. 연간 기상데이터에 위와 같은 방법론이 적용되면 프리즘형 집광부의 연간 내부광속이 산출될 수 있다. 또한 기존 연구에서 제시된 발광효율 산출식과 일사 파장에 따른 시감도를 고려하면 매 시간별 외부조도도 산출이 가능하다. 일사량 측정치와 외부조도 측정치 사이의 상관관계를 분석한 결과 결정계수 $R^2$이 0.99인데 반해 일사량 측정치와 외부조도 계산치 사이의 상관관계 결정계수는 0.95로 측정치 보다 약간 작은 값을 갖는다. 이렇게 산출된 외부조도는 각 입사면의 면적을 반영하여 외부광속으로 변환되고, 앞서 산출된 천공상태별 투과비율이 적용됨으로써 내부광속이 도출될 수 있다. 이와 같은 집광부에 대한 연구를 바탕으로 향후 전송부와 산광부 효율을 도출하고 궁극적으로 집광채광 설비를 통해 실내에 전달되는 연간 빛에너지를 예측할 수 있을 것이다. 또한 본 연구의 방법론은 다른 형태의 집광채광 설비에도 적용이 가능할 것으로 판단되며, 국내 집광채광 설비의 연간 에너지생산량에 대한 폭 넓은 데이터 구축이 가능할 것으로 기대된다.

• KSBB Journal
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• v.23 no.5
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• pp.381-386
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• 2008

Lipophilic ammonia is toxic gas and can easily diffuse across cell membranes. Excess ammonia is implicated in the pathogenesis of several metabolic disorders including hepatic encephalopathy and may result in the death. The purpose of this study was to clarify the inhibition effect of metronidazole on liver cell damage due to ammonia in human Hep G2 cell and rat hepatocytes. The effects of metronidazole were studied in ammonium chloride treated human Hep G2 cell (75 mM) and rat hepatocyte (100 mM) following $0.1{\mu}M$ metronidazole treatment. In MTZ+AC group, cell viabilities increased prominently and LDH activities decreased over 25% than AC group. Furthermore, ammonia level according to ammonium chloride treatment reduced over 30% and lipid peroxidation as an index of cell membrane damage decreased more than twice. By comparison with control, catalase activity showed more than 30% reduction in AC group while less than 10% reduction in MTZ+AC group, respectively. In addition, MTZ+AC group showed the similar cell structure as control in cell morphology study by using light microscope, and represented fluorescent intensity decrement compared with AC group in fluorescent microscopic study with avidin-TRITC fluorescent dye. And cleaved PARP expression due to ammonia reduced twofold or more in MTZ+AC group. As the results suggest, metronidazole may protect the liver cell by inhibiting cell damages due to ammonia and be used for an effective antagonist of ammonia in hyperammonemia.

• Journal of Fashion Business
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• v.7 no.2
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• pp.55-68
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• 2003

The purpose of this research is to expand the realm of a button for a decorative purpose through embossing the effect and gravity of a button in fashion by designing the new ceramic buttons which are mainly used for decorative function in costume. In order to acquire a motif for the design, I analyzed several works of Gustav Klimt. As the result, those feature can be classified into the use of decorative lines, mosaic forms, and harmony of golden yellow and black, and it can be applied to buttons and clothes design. The sort of clay used in manufacturing the ceramic buttons was white clay to have high density and to diffuse light well, and press shaping techniques using plaster mold were employed. The baking was performed in an electronic kiln at $800^{\circ}C$ for the first time and at $1250^{\circ}C$ for the second time. Based on wearable designs in 2002/2003 F/W Trend of Interfashion Planning, I made three pieces of dress which could express the button's capability of decoration with effect. This is expressing a simplified form which shows up in details of and yellow and red pink were used to harmonize with golden yellow clothes. As an application of shapes of foliage in I transformed its size and form to be consistent with a jacket and a tube top. To accord with golden beige costume, I made a curve, showing up in Klimt's paintings, with golden color on a circle shape which was also a main motif in his paintings.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.1
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• pp.7-12
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• 2010

Morphological characteristics of hemp fiber were investigated using a light microscope in order to provide fundamental data for the use of hemp as a papermaking law material. Phloem of hemp is composed of cortical parenchyma cells and bast fiber with thick walls while xylem is composed of vessel, wood fiber and ray parenchyma cells. Also there are solitary pore and radial pore multiple which exist in diffuse porous pattern. Ray cells consist of uniseriate rays and thin walled ray parenchyma cells. Wood fibers are composed of three types: a large diameter fiber with longer length; a large diameter fiber with shorter length; a small diameter fiber with medium length. Vessel elements are composed of: a medium length one; a longer length one; the one whose both end walls have ligules or tails. Parenchyma cells in xylem and pit parenchyma cells have completely different size and shape. For bast fiber, the average length is about 4.4 mm and the width is about $30.5\;{\mu}m$; for vessel element, $600.0\;{\mu}m$ in length and $493.6\;{\mu}m$ in width; for wood fiber, $1000\;{\mu}m$ and $38.9\;{\mu}m$; for parenchyma cell, $50\;{\mu}m$ and $26.4\;{\mu}m$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2113-2120
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• 2013

In this study, an efficient machine vision based inspection system is developed for the in-line measurement of phosphor resin dispensing shapes on LED chip package. Since the phosphor resin (target material) has semitransparent characteristics, illuminated light beam is reflected from the bottom of the chip as well as from the surface. Since such phenomenon can deteriorate inspection reliability, a white LED and a 635nm laser slit beams are experimentally tested to decide suitable illumination optics. Also, specular and diffuse reflection methods are tested to decide suitable optical triangulation. As a result, it can be known that the combination of a white slit beam source and specular reflection method show the best inspection results. The Catmull-Rom spline interpolation is applied to the obtained data to form smoother surface. From the results, it can be conclude that the developed system can be sucessfully applied to the in-line inspection of LED chip packaging process.

• The Korean Journal of Cytopathology
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• v.16 no.1
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• pp.47-51
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• 2005

Plasmablastic lymphoma (PBL) is a recently described aggressive B-cell neoplasm, which usually manifests as a localized disease of the oral mucosa in individuals infected with human immunodeficiency virus (HIV). Recently we encountered a case of plasmablastic lymphoma manifesting in the left maxillary sinus and cervical lymph node of a previously healthy HIV-negative man, 48 years of age. we conducted a fine-needle aspiration smear of the cervical lymph node, and this was found to be highly cellular with numerous large cells exhibiting eccentrically positioned nuclei, prominent nucleoli, and moderate quantities of basophilic cytoplasm. A biopsy of the mass in the maxillary sinus evidenced diffuse growth of similar plasmablastic cells. These tumor cells were negative for the leukocyte common antigens, CD20, CD3, CD30, and EMA. However, the cells tested positive for CD79a and CD138/syndecan-1. The tumor cells also exhibited L-light-chain restriction. The Ki-67 proliferation index was measured at almost 100%. The patient was diagnosed with plasmablastic lymphoma. After three cycles of combination chemotherapy and radiotherapy, the patient went into complete remission, and currently remains in this state.

• Applied Microscopy
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• v.30 no.1
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• pp.61-72
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• 2000

Three fertilization envelopes (FE) have been observed after the artificial insemination of U. unicinctus oocytes. The substances of the first fertilization envelope, which is an effective barrier against excessive sperm, come mainly from the surface coat of the oocyte. The secretions of the cortical granules take part in formation of the 2nd fertilization envelope. Histologically, the 3rd fertilization envelope is not amorphous as seen under light microscope, but contains numerous panicles under electron microscope, which would be contributed to harden the envelope by 60 min after the fertilization. With the substantial similarity between the 1st fertilization envelope and the surface coat of the oocyte, and the coincidence of retraction of microvilli and the formation of the 1st fertilization envelope, it is suggested that the microvilli contain the sperm receptors in U. unicinctus. Some granular substances from the distal part of the acrosome diffuse on the surface coat of the oocyte while the acrosomal tubules penetrate into the surface coat. The acrosomal tubules arise from the proximal part of the acrosome and pass through the acrosomal lumen.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.5
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• pp.519-525
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• 2015

Positive bias stress-induced instability in amorphous indium-gallium-zinc-oxide (a-IGZO) bottom-gate thin-film transistors (TFTs) was investigated under high $V_{GS}$/low $V_{DS}$ and low $V_{GS}$/high $V_{DS}$ stress conditions through incorporating a forward/reverse $V_{GS}$ sweep and a low/high $V_{DS}$ read-out conditions. Our results showed that the electron trapping into the gate insulator dominantly occurs when high $V_{GS}$/low $V_{DS}$ stress is applied. On the other hand, when low $V_{GS}$/high $V_{DS}$ stress is applied, it was found that holes are uniformly trapped into the etch stopper and electrons are locally trapped into the gate insulator simultaneously. During a recovery after the high $V_{GS}$/low $V_{DS}$ stress, the trapped electrons were detrapped from the gate insulator. In the case of recovery after the low $V_{GS}$/high $V_{DS}$ stress, it was observed that the electrons in the gate insulator diffuse to a direction toward the source electrode and the holes were detrapped to out of the etch stopper. Also, we found that the potential profile in the a-IGZO bottom-gate TFT becomes complicatedly modulated during the positive $V_{GS}/V_{DS}$ stress and the recovery causing various threshold voltages and subthreshold swings under various read-out conditions, and this modulation needs to be fully considered in the design of oxide TFT-based active matrix organic light emitting diode display backplane.

• Journal of Plant Biology
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• v.35 no.4
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• pp.393-401
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• 1992

A new species of Dictyostelium, isolated from the subalpine coniferous forests of Halla mountain, was described. The most noteworthy morphological characteristics of this new species were broad petal-like aggregates, concentrated long branches near the bases, typically clustered and delicate sorocarps. DictyosLeLium jloridurn sp. novo was also characterized by 1) elliptical spores with distinctive polar granules, 2) strongly tapering and rough surface of sorophores, 3) frequent occurrence of expanded conical bases, 4) the congealed slime substrate where the several bases were anchored into, 5) compound and c1avata tips. It was quite sensitive to environmental conditions, particularly temperature. Macrocysts and microcysts were not observed. This species can be cultured satisfactorily in assosiation with Esch'||'&'||'pound;richia coLi upon agar media of weak nutrient content, 0_1% lactosepeptone, under diffuse light and darkness. Optimum temperature for growth and develoi)ment was about $18-22^{\circ}C$, below that of most other species of the family.