• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.1-17
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• 2020

Three-dimensional microscopic approaches in histopathology display multiplex properties that present puzzling questions for specimens as related to their comprehensive volumetric information. This information includes spatial distribution of molecules, three-dimensional co-localization, structural formation and whole data set that cannot be determined by two-dimensional section slides due to the inevitable loss of spatial information. Advancement of optical instruments such as two-photon microscopy and high performance objectives with motorized correction collars have narrowed the gap between optical theories and the actual reality of deep tissue imaging. However, the benefits gained by a prolonged working distance, two-photon laser and optimized beam alignment are inevitably diminished because of the light scattering phenomenon that is deeply related to the refractive index mismatch between each cellular component and the surrounding medium. From the first approaches with simple crude refractive index matching techniques to the recent cutting-edge integrated tissue clearing methods, an achievement of transparency without morphological denaturation and eradication of natural and fixation-induced nonspecific autofluorescence out of real signal are key factors to determine the perfection of tissue clearing and the immunofluorescent staining for high contrast images. When performing integrated laboratory workflow of tissue for processing frozen and formalin-fixed tissues, clear lipid-exchanged acrylamide-hybridized rigid imaging/immunostaining/in situ hybridization-compatible tissue hydrogel (CLARITY), an equipment-based tissue clearing method, is compatible with routine procedures in a histopathology laboratory.

• Korean Journal of Materials Research
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• v.9 no.10
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• pp.956-961
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• 1999

When the 0-2 mol% of $\textrm{La}_{3+}$ were added to the nanocrystalline $BaTiO_3$ powders and sintered at $1200~1400^{\circ}C$, the nanocrystailine $BaTiO_3$ ceramics having the average grain size of 110-240 nm were obtained except for when no $\textrm{La}_{3+}$ was added and sintered at > $1350^{\circ}C$. As the average grain size decreased from 240 nm to 110 nm, the tetragonality (c/a) and volume fraction of the $90^{\circ}$ domain decreased, and all the properties such as relative dielectric constant at room temperature, maximum relative dielectric constant at the temperature of phase transformation $\textrm{T}_{c}$ and diffuseness of phase transformation at $\textrm{T}_{c}$ also decreased. The results were attributed to the internal stress induced by inhibition of the $90^{\circ}$ domain formation in the case of finer grain size.

• Journal of the Korean association of regional geographers
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• v.7 no.2
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• pp.17-34
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• 2001

This paper is to analyze how firms in a large firm-led industrial city have carried out the restructuring in the face of radical shifts, with focus on the strategy and the restructuring of firms in Ulsan, a typical industrial district in Korea that is specialized in heavy & chemical industry. It has been well known that the local economy has been led by a small number of large firms, including affiliates of chaebol, and its industrial structure has also been characterised as a clear dichotomy between large firms as a customer and small and medium-size firms as a supplier, which can be called not horizontal but vertical relations. It can identify some tendencies, however, that local companies have been rather dynamically changing in response to increasingly turbulent environment since the Asian crisis. Some are radical, but some incremental. These can be summarized in four distinctive but interlinked ways. First, more than half of local companies surveyed have attempted to change their production systems, mainly from the fordist mass production towards the flexible mass production, seeking both economies of scale and scope. Second, local firms have vigorously continued to reorganize the boundary of the production and the organization, by specializing products and focusing on the core competence in order to save costs and cope with radically changing customer demands in a flexible way. Third, there have been various strategies for the organizational innovation such as the introduction of team organization, the boundary blurring between the managerial and production workers and the intra-firm spin-offs, so as to improve managerial efficiency and competence in the use of internal labour market. Finally, they have tried to be more sensitive to the market and customers. These tendencies seem to be increasingly critical to sustain their competitiveness. To do so, they tend to focus increasingly not only on the competing via the product quality rather than through price, but also to seek to diversify the market and customer firms beyond national boundary.

• The Journal of Engineering Geology
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• v.25 no.4
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• pp.473-484
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• 2015

Geophysical exploration using electric resistivity, ground penetrating radar (GPR), and impedance high-frequency (ZHF) surveys was conducted in Gujwa-eup, Jeju City, Jeju Island, an island in the Korea Strait, to confirm the existence of new caves near known caves. The exploration revealed a number of anomaly zones, presumed to be caves; 27 sites at suitable locations and depth ranges were selected for drilling and further surveys. However, contrary to predictions, most of the anomaly zones were clinker layers or paleosols intercalated with lavas. Only five boreholes intersected caves. The clinker layers and paleosols were possibly detected as anomalies owing to their different physical properties from the other rocks. Two of the five cave-finding boreholes penetrated Yongcheon Cave; a new cave was found at the other. The two boreholes that penetrated Yongcheon Cave were drilled in areas where the cave has not been previously reported, and thus helped correct an error in the cave distribution map. The cave newly discovered in this boring exploration is 180 m long, and it is connected to the upstream part of Dangcheomul Cave (110 m). The cave contains well-developed lava helictites, lava levees, and ropy structures; carbonate speleothems such as soda straws, stalagmites, columns, and curtain shawls are also well preserved. Notably, the unique shape of the carbonate speleothems is attributed to their growth in relation to the cavern water that flowed into the cave along plant roots.

• Journal of Korean Society of Transportation
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• v.27 no.5
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• pp.17-28
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• 2009

There are many limitations in dealing with rapidly changing traffic demand in urban cities. Thus recently, traffic operation and management skills are more emphasized rather than the expansion of traffic facilities. In particular, in the interrupted flow formed by signalized intersections, it is quite important to give optimal signal timing to each intersection with consideration of progression. However, as fixed signal times per direction can affect passing capacity in signalized intersections, the present four-signal phase including a left-turn signal has many limitations, including reduction of directional road capacity when traffic demand is increases dramatically during peak hours. Because of this problem, lots of studies about internal metering techniques for oversaturated signal control skills have progressed but these techniques are not used widely due to the absence of detectors for queue sensing in real-time signal control systems. In this research, a new methodology called the "restrictive left-turn signal control", which is already used at the intersection above Samsung subway station, is suggested in order to reduce control delay of urban arterial roads. The restrictive left-turn signal control allows a driver to make a U-turn and then a right turn instead of turning left in that intersection. With this change, the restrictive left-turn signal control can contribute to increased intersection capacity by reducing the number of signal phases and maximizing the through phase time. However, road structure and traffic conditions at the target intersections should be considered before the adoption of the proposed signal control.

• Journal of the Korean Vacuum Society
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• v.18 no.4
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• pp.296-301
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• 2009

An inductively coupled plasma assisted atomic layer deposition(ICP-ALD) system has been constructed for the deposition of ZnO thin films, and various experiments of ZnO thin films on p-type Si(100) substrates have been carried out to find the self-limiting reaction conditions for the ICP-ALD system under non-plasma circumstances. Diethyl zinc[$Zn(C_2H_5)_2$, DEZn] was used as the zinc precursor, $H_2O$ as the oxidant, and Ar as the carrier and purge gas. At the substrate temperature of $150^{\circ}C$, atomic layer deposition conditions based on self-limiting surface reaction were successfully obtained by series of experiments through the variation of exposure times for DEZn, $H_2O$, and Ar. ZnO deposition was repeated at different substrate temperatures of $90{\sim}210^{\circ}C$. As a result, the thermal process window(ALD window) for ZnO thin films was observed to be $110{\sim}190^{\circ}C$ and the average growth rate was measured to be constant of 0.29 nm/cycle. Properties of the film's microstructure and composition(Zn, O, etc.) were also studied. As the substrate temperature increases, the crystallinity was improved and ZnO(002) peak became dominant. The films deposited at all temperatures were high purity, and the films deposited at high temperatures had the composition ratio between Zn and O closer to one of a stable hexagonal wurtzite structure.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2006.06a
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• pp.495-505
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• 2006

IT기술기반 교육시스템은 인터넷 등장 이전에도 가능성을 인정받아 지속적으로 개발되어 온 분야이며, 교육공학과의 연계로 지식 전날의 이론체계로 각광을 받고 있다. 사이버교유도 인터넷이전부터 다양한 통신방법을 응용하여 개발되었고, 최근 인터넷을 통하여 사이버 교육시스템은 완벽한 기술기반을 갖추게 되였다. 그러나 IT기술의 급격한 변화로 사이버교육시스템은 계속하여 신기술 변화에 적용해야만 한다. 현재 정보통신기술의 변화는 방송 통신망의 융합, 브로드 밴드 네트워킹, 스마트 디바이스의 다양화, 멀티미디어 기술의 고도화로 요약된다. 이 기술의 종합한 작용으로 유비쿼터스 사회의 기반으로 진화되고 있다. 그래서 e-Learning 분야도 기존 인터넷기반 시스템과는 달리 차세대 온라인교육시스템으로 친화되고 있다. IT융합가술 기반의 온라인 교육시스템은 각종 국제표준단체에서 표준안이 제시되고 있다. e-Learning 시스템이란 선기술 기반을 반영한 표준기술을 사용하는 온라인교육시스템을 포괄하는 개념이다. 본 연구에서는 e-Learning 시스템과 유비쿼터스 기술을 반영한 e-Learning을 비교하였다. 그리고 u-Learning 시스템의 기술정립과 EOD(Education On Demand) 시스템에 대하여 연구하였다. 1. u-Learning 정의 정보산업분야를 비롯한 문화, 교육 등 모든 분야에서 유비퀴터스라는 수식어가 붙어 다니고 있다. e- Learning 교육 업계에 따르면 10년 후에는 유비쿼터스는 대중화가 될 것이며, 부가가치 규모는 100조 원에 이를 것으로 추정된다. 그래서 교육산업도 주변 환경이 아날로그 방식에서 IT 기반에 의한 디지털 환경으로 변화되고 있다. 또한 e러닝, T러닝, m러닝, u러닝 등의 용어가 생성되고 있다.키지에어컨에서 사용되고 있는 밀폐형 압축기에 대해서 그림 2에서 나타내고 있는 냉방능력 10tons(120,000Btu/h) 이하를 중심으로 상기의 최근 기술 동향을 간략하게 소개하고자 한다.질표준의 지표성분으로 간주되는 진세노사이드의 절대함량과 그 성분조성 차이에 따른 임상효과의 차별성이 있는지에 대한 검토와, 특히 최근 실험적으로 밝혀지고 있는 사포닌 성분의 장내 세균에 의한 생물전환체의 인체 실험을 통한 효과 검정이 필요하다. 나아가서는 적정 복용량의 설정과 이와 관련되는 생체내 동태 및 생체이용율(bioavilability)에 관한 정보가 거의 없으므로 이것도 금후 검토해야 할 과제로 사료된다. 인삼은 전통약물로서 오랜 역사성과 그동안의 연구결과에 의한 과학성을 가지고 있으므로 건강유지와 병의 예방 및 회복촉진을 위한 보조요법제 또는 기능성 식품으로써의 유용성이 있는 것으로 판단된다. 앞으로 인삼의 활용성 증대를 위해서는 보다 과학적인 임상평가에 의한 안전성 및 유효성 입증과 제품의 엄격한 품질관리의 필요성이 더욱 강조되어야 할 것이다.xyl radical 생성 억제 효과를 보여 주었다. 본 실험을 통하여 BHT 를 제외하고 전반적으로 세포 수준에서의 oxidative stress 에 대한 억제 효과를 확인해 볼 수 있었으며 특히 수용성 항산화제들에서 두드러진 효과를 보여 주었다. 제공하여 내수기반 확충에도 노력해야 할 것 이다.있었다., 인삼이 성장될 때 부분적인 영양상태의 불충분이나 기후 등에 따른 영향을 받을 수 있기 때문에 앞으로 이에 대한 많은 연구가 이루어져야할 것으로 판단된다.태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$<

• Journal of Navigation and Port Research
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• v.45 no.6
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• pp.366-371
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• 2021

This study suggests surface wave communication, which uses a metal surface as a medium, to provide wireless communication in the extreme environment due to surrounding metal materials on vessels. The test was conducted on a G/T 265 tons tug boat to confirm the possibility of surface wave communication between a bridge and each designated space in the ship. As a result, the transmission speed was 13Mbps on average. In a test case of the bridge via the engine room, the transmission speed was 4.3Mbps on engine running and 1.2Mbps on sailing. It overcame this by partially changing the equipment installation location. Surface wave communication in bow storage, a fully enclosed space, had 8Mbps better transmission speed than wireless communication; this confirmed the superiority of surface wave communication in confined spaces on a vessel. Additional surface wave generators were designed and applied to resolve the paint issue. It is expected to use surface wave communication to implement the new wireless solution for Maritime-IoT system on vessels.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.609-622
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• 2019

When the surfactant is dissolved in an aqueous solution, it forms aggregate called micelles (<20 nm) in the solution, and micelles can form the solubilized formulation by supporting the active ingredient therein. Swollen micelles are formulations capable of carrying larger amounts of active ingredient than conventional solubilized formulations at 50~100 nm. Unlike liposomes or nanoemulsions, which require a separate process such as high pressure emulsification, Swollen micelle is a more efficient method of solubilization and particle formation from a productive point of view. In this study, stabilization experiments on swollen micelle formulations were carried out using poloxamer 407, and then optimized formulation experiments for tocopheryl acetate components were performed using Response Surface Methodology (RSM). Tocopheryl acetate, a surfactant that affects solubilization and an active substance, were set as a factor and the correlation between them was confirmed. As the evaluation method, stability and particle size distribution and size were confirmed by temperature and time, and the structure and shape of the swollen micelle carrying the active ingredient were confirmed by FIB. These results show that poloxamer 407 0.500%, octyldodeceth-16 0.387% and tocopheryl acetate 0.945% are the most optimized prescriptions for swollen micelle stabilized with tocopheryl acetate.

• Korean Journal of Heritage: History & Science
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• v.46 no.2
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• pp.206-219
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• 2013

This study aims to estimate firing temperature and physicochemical properties of the four clay bricks excavated from the Maritime Province of Siberia. Analysis result shows that the specimens are composed of clay, quartz and feldspar, and some specimens include carbonized organic materials which were probably added in order to enhance its physical strength in bricks. Major mineral components of the bricks are quartz, illite and clay minerals. The result identifying the existence of silimanite by XRD suggests that white material of the Koc 1 was painted for a certain purpose. Unlike most specimens which contained hematite, several samples contain Mullite. Such result suggests that some bricks were fired at high temperature. Furthermore, the results from TG analysis which does not display exothermic peak which appears at between $800^{\circ}C$ to $1,000^{\circ}C$ but display endothermic peak at $900^{\circ}C$ and it also confirms that they were exposed at $900^{\circ}C$ or higher.