• Title/Summary/Keyword: Dark core

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Change of Stiffness and Impact-Resistance of Flush Door Depending on Core Composition (플러쉬문의 심재구성에 따른 강성도 및 내충격성의 변화)

  • 장상식
    • Journal of the Korea Furniture Society
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    • v.12 no.1
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    • pp.39-45
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    • 2001
  • This study was carried out to evaluate the feasibility of using HDF as surface panels as well as core materials for flush door manufacturing. Several core compositions were developed and applied to manufacture door specimens. Core materials were tested under bending load, door manufacturing process was analysed to find better way of using HDF for door manufacturing, and door specimens were tested under bending, twisting and impact loads. From this study, it was concluded that HDF can be used to manufacture quality flush doors. And it was desirable to use light color HDF as surface panels because dark color HDF caused a problem in manufacturing process by shadow shown through finishing veneer. HDF doors were light, and showed good quality and higher resistance against bending twisting and impact loads.

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Construction of Information Packages for the Operational Efficiency of Dark Archives (다크 아카이브 운영 효율화를 위한 정보패키지 구축)

  • Park, Hyoeun;Lee, Seungmin
    • Journal of the Korean Society for Library and Information Science
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    • v.54 no.4
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    • pp.261-281
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    • 2020
  • The importance of long-term preservation of various types of electronic records through dark archives is gradually increasing. However, the current dark archive does not have an optimized information package structure for long-term preservation of electronic records. In order to address these problems, this research proposed four element categories by re-organizing the OAIS reference model information package based on the core process of the dark archiving. The detailed descriptive items of each category consist of a total of 4 upper-level elements and 27 sub elements based on the OAIS reference model, ISO 23081, Records Management Metadata Standard, ISAD(G), ISAAR(CPF), ISDF, and ISDIAH. This structure can be used as a basis for constructing an information package optimized for dark archiving, and is expected to support the long-term preservation of electronic records more efficiently.

Molecular Hydrogen Outflow in Infrared Dark Cloud Core MSXDC G53.11+00.05

  • Kim, Hyun-Jeong;Koo, Bon-Chul;Pyo, Tae-Soo;Davis, Christopher J.
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.2
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    • pp.41.4-42
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    • 2015
  • Outflows and jets from young stellar objects (YSOs) are prominent observational phenomena in star formation process. Indicating currently ongoing star formation and directly tracing mass accretion, they provide clues about the accretion processes and accretion history of YSOs. While outflows of low-mass YSOs are commonly observed and well studied, such studies for high-mass YSOs have been so far rather limited owing to their large distances and high visual extinction. Recently, we have found a number of molecular hydrogen (H2 1-0 S(1) at 2.12 micron) outflows in the long, filamentary infrared dark cloud (IRDC) G53.2 located at 1.7 kpc from UWISH2, the unbiased, narrow-band imaging survey centered at 2.12 micron using WFCAM/UKIRT. In IRDC G53.2 which is an active star-forming region with ~300 YSOs, H2 outflows are ubiquitously distributed around YSOs along dark filaments. In this study, we present the most prominent H2 outflow among them identified in one of the IRDC cores MSXDC G53.11+00.05. The outflow shows a remarkable bipolar morphology and has complex structures with several flows and knots. The outflow size of ~1 pc and H2 luminosity about ~1.2 Lsol as well as spectral energy distributions of the Class I YSOs at the center suggest that the outflow is likely associated with a high-mass YSO. We report the physical properties of H2 outflow and characteristics of central YSOs that show variability between several years using the H2 and [Fe II] images obtained from UWISH2, UWIFE and Subaru/IRCS+AO188 observations. Based on the results, we discuss the possible origin of the outflow and accretion processes in terms of massive star formation occurring in IRDC core.

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Industrial Technology Leak Detection System on the Dark Web (다크웹 환경에서 산업기술 유출 탐지 시스템)

  • Young Jae, Kong;Hang Bae, Chang
    • Smart Media Journal
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    • v.11 no.10
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    • pp.46-53
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    • 2022
  • Today, due to the 4th industrial revolution and extensive R&D funding, domestic companies have begun to possess world-class industrial technologies and have grown into important assets. The national government has designated it as a "national core technology" in order to protect companies' critical industrial technologies. Particularly, technology leaks in the shipbuilding, display, and semiconductor industries can result in a significant loss of competitiveness not only at the company level but also at the national level. Every year, there are more insider leaks, ransomware attacks, and attempts to steal industrial technology through industrial spy. The stolen industrial technology is then traded covertly on the dark web. In this paper, we propose a system for detecting industrial technology leaks in the dark web environment. The proposed model first builds a database through dark web crawling using information collected from the OSINT environment. Afterwards, keywords for industrial technology leakage are extracted using the KeyBERT model, and signs of industrial technology leakage in the dark web environment are proposed as quantitative figures. Finally, based on the identified industrial technology leakage sites in the dark web environment, the possibility of secondary leakage is detected through the PageRank algorithm. The proposed method accepted for the collection of 27,317 unique dark web domains and the extraction of 15,028 nuclear energy-related keywords from 100 nuclear power patents. 12 dark web sites identified as a result of detecting secondary leaks based on the highest nuclear leak dark web sites.

One-pot synthesis of PdAu bimetallic composite nanoparticles and their catalytic activities for hydrogen peroxide generation

  • Xiao, Xiangyun;Kang, Tae-Uook;Nam, Hyobin;Bhang, Suk Ho;Lee, Seung Yong;Ahn, Jae-Pyung;Yu, Taekyung
    • Korean Journal of Chemical Engineering
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    • v.35 no.12
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    • pp.2379-2383
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    • 2018
  • We report a facile one-pot aqueous-phase synthesis of PdAu bimetallic nanoparticles with different Pd/Au ratio. The synthesis was conducted by co-reduction of Pd and Au precursor using ascorbic acid as a reducing agent and in the presence of polyallylamine hydrochloride (PAH). By high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and energy-dispersive X-ray spectrometry (EDS) analyses, we found that the synthesized nanoparticles had an onion-like core/shell/shell/shell structure with Au-rich core, Pd-rich shell, Au-rich shell, and Pd shell, respectively. We also investigated the catalytic performance of the synthesized PdAu nanoparticles toward hydrogen peroxide generation reaction.

MOLECULAR CORES OF THE HIGH-LATITUDE CLOUD MBM7

  • MINH Y. C.;KIM H. G.;KIM S. J.;BERGMAN P.;JOHANSSON L. E. B.
    • Journal of The Korean Astronomical Society
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    • v.33 no.1
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    • pp.37-45
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    • 2000
  • We have investigated the properties of the high-latitude cloud MBM 7 using the 3 mm transitions of CO, CS, HCN, $HCO^+,\;C_3H_2,\;N_2H^+$, and SiO. The molecular component of MBM 7 shows a very clumpy structure with a size of $\le$0.5 pc, elongated along the northwest-southeast direction, perpendicularly to an extended HI component, which could be resulted from shock formation. We have derived physical properties for two molecular cores in the central region. Their sizes are 0.1-0.3 pc and masses 1-2 M$\bigodot$ having an average volume density $\~2{\times}10^3 cm^{-3}$ at the peak of molecular emission. We have tested the stability of the cores using the full version of the virial theorem and found that the cores are stabilized with ambient medium, and they are expected not to be dissipated easily without external perturbations. Therefore MBM 7 does not seem to be a site for new star formation. The molecular abundances in the densest core appear to be much less (by about one order of magnitude) than the 'general' dark cloud values. If the depletions of heavy elements are not significant in the HLCs compared with those in typical dark clouds, our results may suggest different chemical evolutionary stages or different chemical environments of the HLCs compared with dense dark clouds in the Galactic plane.

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Effects of Light on Disassembly of Chloroplast during Senescence of Detached Leaves in Phaseolus vulgaris

  • Lee Dong-Hee;Hong Jung-Hee;Kim Young-Sang
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.1 no.2
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    • pp.69-80
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    • 1997
  • Effects of light on leaf senescence of Phaseolus vulgaris were investigated by measuring the disassembly of chlorophyll-protein complexes in detached leaves which had been kept in the dark or under light. The loss of chlorophyll accompanied by degradation of chlorophyll-protein complexes. PSI (photosystem I) complex containing LHCI (light harvesting complex of PSI) apoproteins was rapidly decreased after the early stage of dark-induced senescence. RC(reaction center)-Core3 was slightly increased until 4 d and slowly decreased thereafter. As disassembly of LHCII trimer progressed after the late stage of senescence, there was a steady increase in the relative amount of SC(small complex)-2 containing LHCII monomer. On the other hand, white and red light adaptation caused the structural stability of chlorophyll-protein complexes during dark-induced senescence. Particularly, red light was more effective in the retardation of LHCII breakdown than white light, whereas white light was slightly effect in protecting the disassembly of PSI complex compared to red light. These results suggest, therefore, that light may be a regulatory factor for stability of chlorophyll-protein complexes in the senescent leaves.

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VELOCITY ANALYSIS OF M13 BY MAXIMUM LIKELIHOOD METHOD

  • Oh, K.S.;Lin, D. N. C.
    • Journal of The Korean Astronomical Society
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    • v.25 no.1
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    • pp.1-9
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    • 1992
  • We present new approach to analysis of velocity data of globular clusters. Maximum likelihood method is applied to get model parameters such as central potential, anisotropy radius, and total mass fractions in each mass class. This method can avoid problems in conventional binning method of chi-square. We utilize three velocity components, one from line of sight radial velocity and two from proper motion data. In our simplified scheme we adopt 3 mass-component model with unseen high mass stars, intermediate visible stars, and low mass dark remnants. Likelihood values are obtained for 124 stars in M13 for various model parameters. Our preferred model shows central potential of $W_o=7$ and anisotropy radius with 7 core radius. And it suggests non-negligible amount of unseen high mass stars and considerable amount of dark remnants in M13.

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Disruption time scale of merged halos in a dense cluster environment

  • Shin, Jihye;Taylor, James E.;Peng, Eric
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.60.1-60.1
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    • 2016
  • To obtain a reliable estimate of the cold dark matter (CDM) substructure mass function in a dense cluster environment, one needs to understand how long a merged halo can survive within the host halo. Measuring disruption time scale of merged halos in a dense cluster environment, we attempt to construct the realistic CDM mass function that can be compared with stellar mass functions to get a stellar-to-halo mass ratio. For this, we performed a set of high-resolution simulations of cold dark matter halos with properties similar to the Virgo cluster. Field halos outside the main halo are detected using a Friend-of-Friend algorithm with a linking length of 0.02. To trace the sub-halo structures even after the merging with the main halo, we use their core structures that are defined to be the most 10% bound particles.

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