• 폴리머
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• 제34권1호
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• pp.38-44
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• 2010

탄산칼슘/유기계 core-shell 입자를 제조하기 위해 core로는 침강성 탄산칼습을 사용하였고, shell로서는 여러 종류의 methyl methacrylate(MMA), ethyl acrylate(EA), n-butyl acrylate(BA), styrene(St), 2-ethylhexyl acylate(2-EHA)을 사용하여, 반응 온도 유화제, 개시제의 종류와 첨가량을 변화시킨 후에 유화중합을 시켜 최적의 유화중합 조건을 구하였다. 생성된 core-shell 입자의 구조는 FT-IR로, 입자크기와 형태는 입도 분석, SEM, TEM으로 각각 측정하였다. 그리고, 이 core-shell 입자에 부직포를 함침시켜 처리전후의 표면변화는 접촉각으로 확인하였다. 또한, 함침 처리 전후의 부직포/부직포 소재와 관능성 단량체 첨가한 부직포/부직포 소재의 박리 접착강도를 측정하여 상호 비교하였다. 탄산칼슘/유기 core-shell 입자 합성의 경우에는 유화제인 SDBS를 0.5 wt% 첨가한 탄산칼슘을 core로 하여 MMA와 0.1 wt% 농도의 APS를 단계적으로 주입하여 중합함으로써 탄산칼슘입자 표면에 단량체의 중합이 잘 유도될 수 있었으며 중합 도중에 새로운 중합체 입자의 생성이 적었다.

• 방송공학회논문지
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• 제17권6호
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• pp.1004-1013
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• 2012

3D 영상 산업의 활성화와 함께 3D 영상이 적용됨으로써 유망한 산업 분야 중 하나가 게임이다. 2D에서 3D 그래픽으로 그리고 현재는 3D 입체영상으로 진화하면서 이용자에게 깊이감을 제공함으로써 더 큰 즐거움을 주고 있다. 그러나 우리나라 18세 이상 성인 중절반이 안경 또는 콘택트렌즈를 착용하고 있을 정도로 안경 착용자가 많은 환경에서 3D 영상을 즐기기 위해서 또 다른 안경인 3D 안경을 착용해야 하는 것은 큰 불편이 아닐 수 없다. 본 연구에서는 게임에서의 입체영상 및 안경 착용여부가 영상의 특성, 프레즌스 그리고 피로도 등에 어떠한 영향을 미치는지 알아보고자 했으며, 실험결과 디스플레이와 안경착용의 상호작용효과는 프레즌스 구성요소 중 시간관여에서 유의미하게 나타났다. 2D 영상에서는 안경 착용자가 높은 반면 3D 입체영상에서는 안경 비착용자가 높게 인지하였다. 그리고 인지된 특성과 피로도 변인에서는 영상 여부의 주효과에서만 유의미한 것으로 나타났다. 인지된 특성 구성요소 중 선명도에서는 3D 입체영상 보다 2D 영상의 화질이 좋다고 평가하였으며, 피로도는 2D 영상 보다는 3D 입체영상에서 높은 것으로 나타났다.

• 대한조선학회논문집
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• 제57권4호
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• pp.213-220
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• 2020

In the present paper, implosion responses of two adjacent cylindrical tubes under external hydrostatic pressure were experimentally investigated. The cylinder models were fabricated of aluminium alloy 6061-T6 commercial tubes. In the experiment, a pair of two-cylinders were placed inside of a support frame in a medium-size pressure chamber, whose design pressure was 6.0MPa. The distance between the two-cylinders was 30 millimeter measured from outer shell at the mid-length. The implosion tests were performed with water and compressed nitrogen gas as the pressurizing media. The ambient static pressure of the chamber and local dynamic pressure near the two-imploded models were measured simultaneously. It was found that the energy released during an implosion from the first, weaker cylinder triggered the instability of the second, stronger cylinders. In other words, the resulting shock wave of the first implosive impact from the weaker cylinder could cause the premature failure of the neighboring stronger cylinders. The non-contact implosion phenomena from the two-cylindrical tube were clearly observed.

• Bulletin of the Korean Chemical Society
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• 제24권5호
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• pp.605-609
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• 2003

The lower-order lithium organocyanocuprate compound, (THF)₃Li(NC)Cu($C_6$H₃-2,6-Mes₂) (1), and the bulky terphenyl Grignard reagent, Br(THF)₂Mg($C_6$H₃-2,6-Trip₂) (2), have been synthesized and structurally characterized both in the solid state by single crystal x-ray crystallography and in solution by multi-nuclear NMR and IR spectroscopy. The compound (1) was isolated as a monomeric contact ion-pair in which the C (organic ipso)-Cu-CN-Li atoms are coordinated linearly. The lithium has a tetrahedral geometry as a result of solvation by three THF molecules. The compound (1) is the first example of fully characterized monomeric lower order lithium organocyanocuprate. The bulky Grignard reagent (2) was also isolated as a monomer in which the magnesium, solvated by two THF molecules, has a distorted tetrahedral geometry. The crystals of (1) possess triclinic symmetry with the space group $P{\={1}}$, Z = 2, with a = 12.456(3) Å, b = 12.508(3) Å, c = 13.904(3) Å, α = 99.81°, β = 103.72(3)°, and γ = 119.44(3)°. The crystals (2) have a monoclinic symmetry of space group $P2_{1/C}$, Z = 4, with a = 13.071(3) Å, b = 14.967(3) Å, c = 22.070(4) Å, and β = 98.95(3)°.

• 천문학회지
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• 제51권5호
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• pp.129-142
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• 2018

The DEEP-South (the Deep Ecliptic Patrol of the Southern Sky) photometric census of small Solar System bodies produces massive time-series data of variable, transient or moving objects as a by-product. To fully investigate unexplored variable phenomena, we present an application of multi-aperture photometry and FastBit indexing techniques for faster access to a portion of the DEEP-South year-one data. Our new pipeline is designed to perform automated point source detection, robust high-precision photometry and calibration of non-crowded fields which have overlap with previously surveyed areas. In this paper, we show some examples of catalog-based variability searches to find new variable stars and to recover targeted asteroids. We discover 21 new periodic variables with period ranging between 0.1 and 31 days, including four eclipsing binary systems (detached, over-contact, and ellipsoidal variables), one white dwarf/M dwarf pair candidate, and rotating variable stars. We also recover astrometry (< ${\pm}1-2$ arcsec level accuracy) and photometry of two targeted near-earth asteroids, 2006 DZ169 and 1996 SK, along with the small- (~0.12 mag) and relatively large-amplitude (~0.5 mag) variations of their dominant rotational signals in R-band.

• Korean Journal of Geomatics
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• 제2권1호
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• pp.47-55
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• 2002

Remote sensing is the science and art of obtaining information about an object, area or phenomenon through the analysis of data acquired by a device that is not in contact with the object, area, or phenomenon under investigation./sup 1)/ EOC (Electro -Optical Camera) sensor loaded on the KOMPSAT-1 (Korea Multi- Purpose Satellite-1) performs the earth remote sensing operation. EOC can get high-resolution images of ground distance 6.6m during photographing; it is possible to get a tilt image by tilting satellite body up to 45 degrees at maximum. Accordingly, the device developed in this study enables to obtain images by photographing one pair of tilt image for the same point from two different planes. KOMPSAT-1 aims to obtain a Korean map with a scale of 1:25,000 with high resolution. The KOMPSAT-1 developed automated feature extraction system based on stereo satellite image. It overcomes the limitations of sensor and difficulties associated with preprocessing quite effectively. In case of using 6, 7 and 9 ground control points, which are evenly spread in image, with 95% of reliability for horizontal and vertical position, 3-dimensional positioning was available with accuracy of 6.0752m and 9.8274m. Therefore, less than l0m of design accuracy in KOMPSAT-1 was achieved. Also the ground position error of ortho-image, with reliability of 95%, is 17.568m. And elevation error showing 36.82m was enhanced. The reason why elevation accuracy was not good compared with the positioning accuracy used stereo image was analyzed as a problem of image matching system. Ortho-image system is advantageous if accurate altitude and production of digital elevation model are desired. The Korean map drawn on a scale of 1: 25,000 by using the new technique of KOMPSAT-1 EOC image adopted in the present study produces accurate result compared to existing mapping techniques involving high costs with less efficiency.

• 대한조선학회논문집
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• 제57권1호
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• pp.23-34
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• 2020

This paper covers the development of prediction techniques for ice load on ice-breakers operating in continuous ice-breaking under level ice conditions using particle-based continuum mechanics. Ice is assumed to be a linear elastic material until the fracture occurs. The maximum normal stress theory is used for the criterion of fracture. The location of the crack can be expressed using a local scalar function consisting of the gradient of the first principal stress and the corresponding eigen-vector. This expression is used to determine the relative position of particle pair to the new crack. The Hertz contact model is introduced to consider the collisions between ice fragments and the collisions between hull and ice fragments. In order to verify the developed technique, the simulation results for the three-point bending problems of ice-specimen and the continuous ice-breaking problem around a wedge-type model ship with bow angle of 20° are compared with the experimental results carrying out at Korea Research Institute of Ships and Ocean Engineering (KRISO).

• 한국광학회지
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• 제19권4호
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• pp.249-254
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• 2008

새 구조의 액정 엑스선 감지기를 만들었다. 이것은 액정판을 만들고 유리판을 얇게 식각한 다음, 그 유리판 위에 반사막과 광전도층을 연속하여 입힌 구조이다. 새 구조의 액정엑스선 감지기는 공정의 안정성, 대면적화, 감도 등에서 이미 상품화된 엑스선 감지기와도 충분히 경쟁할 수 있으며, 따라서 성공적으로 상용화 할 수 있음을 확인했다.

• Applied Microscopy
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• 제39권2호
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• pp.149-156
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• 2009

거미의 외골격은 그 특성상 소수성이며 접착성이 없는 구조를 지니고 있지만, 일부 배회성 거미들은 부드럽고 건조한 표면을 따라 보행할 수 있는 독특한 접착장치를 지니고 있다. 본 연구는 거미류 접착보행 장치의 미세구조적 특성을 규명하기 위하여 깡충거미과의 세발깡충거미 (Plexippus setipes)를 실험재료로 하여 4쌍의 보행지에 형성된 접착장치를 고배율의 주사전자현미경으로 관찰하였다. 그 결과, 각각의 보행지에서 2개의 발톱(claw)과 강모다발 (scopula)이 관찰되었는데, 건조한 표면에 대한 부착력은 강모다발의 특이한 구조로부터 발생됨이 확인되었다. 각 보행지마다 약 160개의 강모 (seta)가 관찰되었는데, 표면과 접촉을 이루는 방향에 따라 두 집단의 강모다발로 구분되었다. 강모의 배면을 따라 형성된 무수한 감각모로 인해 인접 강모들과의 접착이 차단되어 있었고, 강모의 복면에서는 고밀도로 밀집된 미세강모 (setule)들이 관찰되었다. 미세강모의 첨단부는 역삼각형의 주걱모양으로 펼쳐져 충분한 접촉면을 확보하고 있었으며, 미세강모의 유연성과 그 표면에 형성된 큐티클 함몰부의 미세구조 등이 깡충거미류 부착장치의 특성임을 확인할 수 있었다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2009년도 학술논문요약집
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• pp.84-85
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• 2009

New approaches for detecting, preventing and remedying environmental damage are important for protection of the environment. Procedures must be developed and implemented to reduce the amount of waste produced in chemical processes, to detect the presence and/or concentration of contaminants and decontaminate fouled environments. Contamination can be classified into three general types: airborne, surface and structural. The most dangerous type is airborne contamination, because of the opportunity for inhalation and ingestion. The second most dangerous type is surface contamination. Surface contamination can be transferred to workers by casual contact and if disturbed can easily be made airborne. The decontamination of the surface in the nuclear facilities has been widely studied with particular emphasis on small and large surfaces. The amount of wastes being produced during decommissioning of nuclear facilities is much higher than the total wastes cumulated during operation. And, the process of decommissioning has a strong possibility of personal's exposure and emission to environment of the radioactive contaminants, requiring through monitoring and estimation of radiation and radioactivity. So, it is important to monitor the radioactive contamination level of the nuclear facilities for the determination of the decontamination method, the establishment of the decommissioning planning, and the worker's safety. But it is very difficult to measure the surface contamination of the floor and wall in the highly contaminated facilities. In this study, the poly(styrene-ethyl acrylate) [poly(St-EA)] core-shell composite polymer for measurement of the radioactive contamination was synthesized by the method of emulsion polymerization. The morphology of the poly(St-EA) composite emulsion particle was core-shell structure, with polystyrene (PS)as the core and poly(ethyl acrylate) (PEA) as the shell. Core-shell polymers of styrene (St)/ethyl acrylate (EA) pair were prepared by sequential emulsion polymerization in the presence of sodium dodecyl sulfate (SOS) as an emulsifier using ammonium persulfate (APS) as an initiator. The polymer was made by impregnating organic scintillators, 2,5-diphenyloxazole (PPO) and 1,4-bis[5-phenyl-2-oxazol]benzene (POPOP). Related tests and analysis confirmed the success in synthesis of composite polymer. The products are characterized by IT-IR spectroscopy, TGA that were used, respectively, to show the structure, the thermal stability of the prepared polymer. Two-phase particles with a core-shell structure were obtained in experiments where the estimated glass transition temperature and the morphologies of emulsion particles. Radiation pollution level the detection about under using examined the beta rays. The morphology of the poly(St-EA) composite polymer synthesized by the method of emulsion polymerization was a core-shell structure, as shown in Fig. 1. Core-shell materials consist of a core structural domain covered by a shell domain. Clearly, the entire surface of PS core was covered by PEA. The inner region was a PS core and the outer region was a PEA shell. The particle size distribution showed similar in the range 350-360 nm.