• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.301-306
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• 1998

Korea Aerospace Research Institute (KARI) is developing a Korea Multi-Purpose Satellite I (KOMPSAT-I) which accommodates Electro-Optical Camera (EOC), Ocean Scanning Multi-spectral Imager (OSMI), and Space Physics Sensor (SPS). The satellite has the weight of about 500kg and will be operated on the 10:50 AM sun-synchronized orbit with the altitude of 685 km. The satellite will be launched in 1999 and its lifetime is expected to be over 3 years. The main mission of EOC is the cartography to provide the images from a remote earth view for the production of 1/25000-scale maps of KOREA. EOC collects 510 ~ 730 nm panchromatic imagery with the ground sample distance(GSD) of 6.6 m and the swath width of 17 km by push broom scanning. EOC also can scan $\pm$45 degree across the ground track using body pointing method. The primary mission of OSMI is worldwide ocean color monitoring for the study of biological oceanography. It will generate 6 band ocean color images with 800 km swath width and 1km GSD by whiskbroom scanning. OSMI is designed to provide on-orbit spectral band selectability in the spectral range from 400 nm to 900 nm through ground command. This flexibility in band selection can be used for various applications and will provide research opportunities to support the next generation sensor design. SPS consists of High Energy Particle Detector (HEPD) and ionosphere Measurement Sensor (IMS). HEPD has missions to characterize the low altitude high-energy Particle environment and to study the effects of radiation environment on microelectronics. IMS measures densities and temperature of electrons in the ionosphere and monitors the ionospheric irregularities at the KOMPSAT orbit.

• Food Science of Animal Resources
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• v.30 no.6
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• pp.905-909
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• 2010

Two sets of data on carcass traits and beef cut parameters were used to investigate the relationships between carcass and beef cut measurements, which can be used to make predictions of retail cut percentages. One set had a total of 1,141 measurements of Hanwoo cattle of three different sex origins, which were slaughtered in an abattoir located at the National Institute of Animal Science, RDA, Korea from 1996 to 2008. To develop prediction models for retail cut percentage with higher accuracies than the current model, another set consisting of a total of 13,389 records of carcass and beef cut traits were collected from 30 abattoirs and butcheries in Korea from 2008 to 2009. Bulls yielded heavier and leaner carcasses than steers. High correlation coefficients were estimated between amount of body fat and percent retail cut (-0.82) as well as between back fat thickness (BF) and percent retail cut (-0.62). The amount of retail cut, however, was highly correlated with body weight before slaughter (BW, 0.95) or with cold carcass weight (CWT, 0.94). Relationships between percent retail cut and measurable beef yield traits, BF, loin eye area (LEA) or CWT varied by sex class, which must be considered for development of a prediction model with high accuracy. Models of data for all breeds and sexes fit the effects of breed, sex, and interaction of abattoir by butchers, whereas models of data for each breed and sex fit the effect of interaction of abattoir by butcher only. Due to possible future changes in back fat control, we performed a log transformation of BF. Our new models fit better than the currently used model.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.55-55
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• 2011

질소 등을 GST225 상변화재료에 첨가시켜 비저항을 증가시킴으로서 PCRAM의 동작 전류를 감소시킨 연구가 선행된 바 있다. 본 연구에서는 GST225와 달리 고속 동작 특성을 갖는 것으로 널리 알려진 Ge-doped SbTe (GeST) 상변화 재료에 Carbon을 첨가하여 박막 특성을 연구하여 동작 전류 감소의 가능성을 타진하였다. 실험을 위한 박막 제작을 위해 2 inch size의 GeST 및 C doped GeST (C-GeST) single target을 이용하여 RF magnetron co-sputtering 하였다. 박막은 carbon이 첨가되지 않은 GeST와 carbon 첨가량이 늘어나는 순서로 C-GeST 1, C-GeST 2, C-GeST 3로 구성된다. 이 때 제작한 박막의 composition analysis를 위해 XRF/RBS/AES가 사용되었고 제작된 박막의 기본적인 특성평가를 위해 resistivity(${\rho}$)와 crystallzation temp.(Cx), surface morphology(AFM), x-ray diffraction pattern(XRD)를 측정하였다. 실험결과 GeST, C-GeST 1, C-GeST 2, C-GeST 3 박막의 Cx는 각각 209, 225, 233, $245^{\circ}C$로 측정되어 carbon 첨가량이 증가됨에 따라 결정화 온도가 증가되는 것을 알 수 있었다. 또한 ${\rho}$도 마찬가지로 annealing 온도를 약 $320^{\circ}C$로 할 경우 ${\rho}$(as-dep)와 ${\rho}$(crystalline) 모두 0.03 / $2.61*10^{-6}$, 0.08 / $7.93*10^{-6}$, 0.09 / $11.99*10^{-6}$, 0.13 / $13.49*10^{-6}{\Omega}{\cdot}m$로 증가하였다. 증가된 ${\rho}$의 원인이 박막의 grain size의 감소라고 단언 할 수는 없으나 AFM 측정결과 grain이라고 추측되는 박막 feature들의 size가 점차 감소하는 것을 확인하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.53-53
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• 2011

As the dimension of Cu interconnects has continued to reduce, its resistivity is expected to increase at the nanoscale due to increased surface and grain boundary scattering of electrons. To suppress increase of the resistivity in nanoscale interconnects, alloying Cu with other metal elements such as Al, Mn, and Ag is being considered to increase the mean free path of the drifting electrons. The formation of Al alloy with a slight amount of Cu broadly studied in the past. The study of Cu alloy including a very small Al fraction, by contrast, recently began. The formation of Cu-Al alloy is limited in wet chemical bath and was mainly conducted for fundamental studies by sputtering or evaporation system. However, these deposition methods have a limitation in production environment due to poor step coverage in nanoscale Cu metallization. In this work, gap-filling of Cu-Al alloy was conducted by cyclic MOCVD (metal organic chemical vapor deposition), followed by thermal annealing for alloying, which prevented an unwanted chemical reaction between Cu and Al precursors. To achieve filling the Cu-Al alloy into sub-100nm trench without overhang and void formation, furthermore, hydrogen plasma pretreatment of the trench pattern with Ru barrier layer was conducted in order to suppress of Cu nucleation and growth near the entrance area of the nano-scale trench by minimizing adsorption of metal precursors. As a result, superconformal gap-fill of Cu-Al alloy could be achieved successfully in the high aspect ration nanoscale trenches. Examined morphology, microstructure, chemical composition, and electrical properties of superfilled Cu-Al alloy will be discussed in detail.

• Korean Journal of Materials Research
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• v.6 no.12
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• pp.1221-1232
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• 1996

용접부 인성을 향상시키기 위해 Ti 산화물을 첨가한 Ti 산화물강에 대하여 용접시 최고가 열온도와 냉각속도의 변화가 용접열영향부의 미세조직에 미치는 영향을 조사하였다. 용접열영향부의 인성향상에 기여하는 acicular ferrite는 140$0^{\circ}C$ 이상의 최고가열온도와 $\Delta$t800-500가 40초보다 빠른 냉각속도에서 활발해 생성되었다. 오스테나이트 결정립내에서 개재물로부터 핵생성된 일차 acicular ferite의 생성량은 전체 aicular ferrite의 약 20% 정도로 적었으며 대부분의 acicular ferrite는 일차 acicular ferrite로부터 생성된 이차 acicular ferrite인 것으로 나타났다. 이차 acicular ferrite는 plate사이에 Fe3C층이 존재하는 것으로 보아 확산기구에 의해 생성되는 것으로 생각된다. 개재물은 TiO, TiO2, TiN, MnS, AI2O3 MnO(galaxite)등으로 구성된 복합상이었으며 개재물이 일차 acicular ferrite의 핵생성 site로 작용하기 위해서는 약 1$\mu\textrm{m}$이상의 크기가 효과적인 것으로 나타났다. Ti 산화물과 TiN는 직접적인 acicular ferrite의 핵생성 site로 작용하기보다는 MnS, galaxite 등의 석출 site로 작용하여 개재물의 크기를 증가시킴으로써 acicular ferrite의 생성을 촉진시키는 것으로 생각된다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.125-135
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• 2011

The bond properties between polypropylene fiber reinforced cement composites and structural synthetic fiber have been investigated. in this paper. Three levels of polypropylene fibers volume fraction were used, 0.10%, 0.15%, and 0.20% in a series of Dog-bone pull out tests. The bond strength between structural synthetic fiber and polypropylene fiber reinforced cement composites increases with the volume fraction of polypropylene fiber, but the bond strength decreases above the amount of 0.20% by volume of polypropylene fiber reinforced cement composites. Also, the addition of polypropylene fiber a significant improved the interface toughness and the frictional resistance, The microstructure of structural synthetic fiber surface was investigated after the pullout test. The scratched of structural synthetic fiber increased with the polypropylene fiber volume fraction.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.373-379
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• 2016

The thermal control device for the periodic working component combined solid-liquid phase change material (PCM) with heat pipes is designed and numerically studied. Due to high latent heat and retaining constant temperature during melting process the component peak temperature, not withstanding small radiator size, is reduced. The warm-up heater power consumption to keep the minimum allowed temperature is also cut down since the accumulated thermal energy is released through the solidification. The thermal buffer mass (TBM) made of Al can give the similar effect but the mass and power consumption of warm-up heater should increase compared to PCM. The amount of PCM can be optimized depending on the component heat dissipation and on/off duty time.

• Journal of the Korean Home Economics Association
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• v.44 no.7 s.221
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• pp.63-72
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• 2006

The purpose of this study was to survey the wearing practices and problems in the working uniform for volunteer fire brigade members and then to develop its design with a improved movement adaptability, physical suitability, ease for equipment accommodation, functionality, convenience and fit. Based on the questionnaire, we have made a testing uniform for volunteer fire brigade members first. Through a subjective analysis for functionality and apparence, we suggested a final design. The final design includes the following elements: 1. It was a two-piece style composed of a jumper and trousers with the upper garments pulled out. Raglan sleeves were used to increase arm's movement scope. Pleats and velcro tapes were attached along the base hem of sleeves to prevent heat transmission. 2. Various types of pockets were attached to secure enough space for keeping things. 3. In trousers, spare space was given at the buttock area with rubber string inserted only at selected part of side lines, and knee pads were attached to prevent wearing out.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.7
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• pp.298-304
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• 2002

Transmuted impurity atoms formed in neutron-irradiated ZnO thin films were theoretically identified first and then experimentally confirmed by photoluminescence (PL). ZnO thin films grown by plasma-assisted molecular beam epitaxy were irradiated by neutron beam at room temperature. The ZnO films consist of eight constituent (Zn and O) isotropes, of which four are transmutable by neutron-irradiation; $^{64}$ , $^{68}$ Zn, $^{70}$ Zn and $^{18}$ O were expected to transmute into $^{65}$ Cu, $^{69}$ Ga, $^{71}$ Ga, and $^{19}$ F, respectively. The concentrations of these transmuted atoms were estimated in this study by considering natural abundance, neutron fluence and neutron cross section. The neutron-irradiated ZnO thin films were characterized by PL. In the PL spectra of the ZnO thin films, the Cu-related PL peaks were seen, but the Ga- or F-associated PL peaks were absent. This observation confirmed the existence of $^{65}$ Cu in the ZnO, but it could not do the formation of the other two. In this paper, the emission mechanism of Cu impurities is described and the reason for the absence of the Ga- or F-associated PL peaks is discussed as well.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.3
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• pp.200-208
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• 1999

In this paper, the corona discharge is analyzed by Finite Element Method(FEM) combined with Flux-corrected Transport(FCT) algorithm. In the previous papers, Finite Difference Method(FDM) combined with FCT was used. Usually in the FDM, the regionof interest is discretized with structured grids. But to refine local regions with same resolution, much more grids are required for the structured grids than for unstructured grids than for unstructured grids. Therefore, we propose the FEM-FCT method to simulate the corona discharge. The proposed method has good flexibility in model shape and can reduce the computational cost by the local refinement where the physical quantities have steep gradients. Using the proposed method, we study the streamer growth of parallel plate electrodes which is initiated by the low and high perturbation density. We find that the varying the initial density of perturbation has very little effect on the streamer propagation. And the corona discharge of the rod-to-plane electrode is simulated. On the surface of the rod electrode, the high concentration of the electric field gives rise to many number of streamer seeds. The strong axial streamer propagate to the plane electrode. The weaker non-axial streamer repel each other and stop growing more. The results are very similar to those of the papers which used the FDM-FCT method on structured grids. Thus we can conclude that the proposed FEM-FCT method is more efficient than the conventional FDM-FCT method by virtue of the reduction in computational grids number.