• Title/Summary/Keyword: Structural Transition

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A Structural Equation Model of Factors Influencing Posttraumatic Growth of Earthquake Victims (지진 피해자의 외상 후 성장에 영향을 미치는 요인들 간의 구조모형)

  • Kwak, Minyeong
    • Research in Community and Public Health Nursing
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    • v.30 no.3
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    • pp.345-356
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    • 2019
  • Purpose: The purpose of this study is to construct and test a structural equation model of posttraumatic growth (PTG) of earthquake victims based on Tedeschi and Calhoun's model (2004). Methods: Data were collected from 195 earthquake victims living in K. City. The exogenous variables include distress perception, resilience, and social support, and the endogenous variables include intrusive rumination, deliberate rumination, and posttraumatic growth. For data analysis, descriptive statistics, factor analysis, and structural equation modeling were performed. Results: The modified model showed a good fitness to the data. Moreover, 6 of the 9 paths of the final model were statistically significant, which include PTG affected by deliberate rumination (${\beta}=.58$, p<.001), resilience (${\gamma}=.18$, p=.001), and distress perception (${\gamma}=.20$, p=.002). These predictors explain 51.8% of variance in posttraumatic growth. Conclusion: Based on the results of this study, it is necessary to develop and disseminate preventive intervention programs to increase the resilience of earthquake-prone communities. In addition, after exposure to a community-scale traumatic event such as earthquake, we should provide social supports to alleviate distress perception and transition from intrusive rumination to deliberate rumination so that we can seek new meaning from the earthquake and facilitate posttraumatic growth.

Comparative Study on the Weldability of Different Shipbuilding Steels

  • Laitinen, R.;Porter, D.;Dahmen, M.;Kaierle, S.;Poprawe, R.
    • International Journal of Korean Welding Society
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    • v.2 no.2
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    • pp.7-13
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    • 2002
  • A comparison of the welding performance of ship hull structural steels has been made. The weldability of steels especially designed for laser processing was compared to that of conventional hull and structural steels with plate thicknesses up to 12 mm. Autogenous laser beam welding was used to weld butt joints as well as skid and stake welded T-joints. The welds were assessed in accordance with the document "The Classification Societies" Requirements for Approval of $CO_2$ Laser Welding Procedures" Small imperfections in the weld only grew slightly in root bend tests and they only had a minor influence on the fatigue properties of laser fillet welded joints. In Charpy impact tests, the 27 J transition temperature of the weld metal and HAZ ranged from below -60 to $-50^{\circ}C$. The amount of martensite in the weld metal depended on the carbon equivalent of the steel with the highest amounts and highest hardness levels in conventional EH 36 (389 HV 5). Thermomechanically rolled steels contained less martensite and showed a correspondingly lower maximum hardness.ximum hardness.

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COMPARATIVE STUDY ON THE WELDABILITY OF DIFFERENT SHIPBUILDING STEELS

  • Laitinen, R.;Porter, D.;Dahmen, M.;Kaierle, S.;Poprawe, R.
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.222-228
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    • 2002
  • A comparison of the welding performance of ship hull structural steels has been made. The weldability of steels especially designed for laser processing was compared to that of conventional hull and structural steels with plate thicknesses up to 12 mm. Autogenous laser beam welding was used to weld butt joints as well as skid and stake welded T-joints. The welds were assessed in accordance with the document "The Classification Societies′ Requirements for Approval of $CO_2$ Laser Welding Procedures". Small imperfections in the weld only grew slightly in root bend tests and they only had a minor influence on the fatigue properties of laser fillet welded joints. In Charpy impact tests, the 27 J transition temperature of the weld metal and HAZ ranged from below -60 to -5$0^{\circ}C$. The amount of martensite in the weld metal depended on the carbon equivalent of the steel with the highest amounts and highest hardness levels in conventional EH 36 (389 HV 5). Thermomechanically rolled steels contained less martensite and showed a correspondingly lower maximum hardness.

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Evaluation of influence of dissolved oxygen on corrosion behaviors of FeCrW model alloys in 360 ℃ water

  • Jun Yeong Jo;Chi Bum Bahn;Hwasung Yeom
    • Nuclear Engineering and Technology
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    • v.56 no.10
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    • pp.4404-4411
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    • 2024
  • The dissolved oxygen in a coolant can affect the oxidation properties of structural materials. A desirable oxide phase formation is achieved by manipulating the oxygen level in the coolant, which can mitigate structural material degradation in nuclear power plants. Therefore, the role of dissolved oxygen in the corrosion of structural materials in aqueous environments needs to be understood. In this study, a short-term corrosion test (up to 300 h) of Ferritic/Martensitic steels (F/M steels; FeCrW model alloys), namely, Fe12Cr1W, Fe9Cr1W, and Fe9Cr, in stagnant water at 360 ℃ was performed in a pressurized autoclave with the dissolved oxygen concentration controlled to 1 ppm or a very low level (<1 ppm). The results of the corrosion tests showed that an increase in the oxygen level in the water elevated the corrosion potential, allowing the phase transition of iron oxide from magnetite (Fe3O4) to hematite (Fe2O3), whereas there was no significant correlation between the concentrations of the alloying elements Cr and W and the oxide growth rate. In addition, hematite was found to mitigate further oxide growth. Finally, a mechanism for the growth of the initial oxide layer was proposed based on the experimental results.

Properties of $Cl^-$ Binding Site in Oxygen-Evolving Complex of Photosystem II Studied by FTIR Spectroscopy

  • Koji Hasegawa;Kim, Yukihiro ura;Asako Ishii;Jun Minagawa;Ono, Taka-aki
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.376-378
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    • 2002
  • Role of cl$^{[-10]}$ in photosynthetic oxygen-evolving complex was studied by light-induced Fourier transform infrared (FTIR) spectroscopy. cl$^{[-10]}$ depletion resulted in the suppression of amide I and amide II IR modes upon S$_1$ to S$_2$ transition. Br$^{[-10]}$ , 1$^{[-10]}$ and N0$_3$$^{[-10]}$ substituted FTIR difference spectra were very similar to that in cl$^{[-10]}$ reconstitution. F$^{[-10]}$ and $CH_3$COO$^{[-10]}$ substituted spectra were largely distorted. We succeeded in detecting the structural change of N0$_3$ $^{[-10]}$ in the cl$^{[-10]}$ site upon the S$_1$ to S$_2$ transition from $^{14}$ N0$_3$$^{[-10]}$ /$^{15}$ N0$_3$$^{[-10]}$ difference spectrum.

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Quantitative Research about a Suitable Hanok Type Based on the Local Characteristics by Geographic Information - Focused on Special Architectural District for Hanok Promotion in Suwon Hwaseong Fortress - (지역 특성에 적합한 한옥유형 도출을 위한 정량적 연구 - 수원 한옥촉진 특별건축구역을 대상으로 -)

  • Kim, Wan
    • Journal of the Korean housing association
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    • v.26 no.2
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    • pp.21-28
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    • 2015
  • The purpose of this paper is to estimate and deduct appropriate Hanok type within Suwon Hwaseong Fortress in which formula Hanok type has not remained. To do so, urban change according to chronology is analyzed and architectural aspect of transition is collected. By using geographic information in Suwon Hwaseong Fortress, present urban structural density, status of architecture and chronological aspect of transition in one-story buildings is surveyed. Through these data, appropriate Hanok form and density to the area is suggested. As a result, Hanok with two or more stories is economically suitable because its average plottage is excessively narrow. And back trowelling is desirable to construct walls in some concentrated areas with Hanok through arrangement of construction. Also in the other building sites, Hanoks are formed by a standard for separation to the property line. However it is necessary that exist standard about separation of property line is institutionally alleviated.

Flight Control Test of Quadrotor-Plane with Hybrid Flight Mode of VTOL and Fast Maneuverability (Hybrid 비행 모드를 갖는 Quadrotor-Plane의 비행제어실험)

  • Kim, Dong-Gyun;Lee, Byoungjin;Lee, Young Jae;Sung, Sangkyung
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.9
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    • pp.759-765
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    • 2016
  • This paper presents the principle, dynamics modeling and control, hardware implementation, and flight test result of a hybrid-type unmanned aerial vehicle (UAV). The proposed UAV was designed to provide both hovering and fixed-wing type aerodynamic flight modes. The UAV's flight mode transition was achieved through the attitude transformation in pitch axis, which avoids a complex rotor tilt mechanism from a structural and control viewpoint. To achieve this, a different navigation coordinate was introduced that avoids the gimbal lock in pitch singularity point. Attitude and guidance control algorithms were developed for the flight control system. For flight test purposes, a quadrotor attached with a tailless fixed-wing structure was manufactured. An onboard flight control computer was designed to realize the navigation and control algorithms and the UAV's performance was verified through the outdoor flight tests.

In-situ monitoring of oxidation states of vanadium with ambient pressure XPS

  • Kim, Geonhwa;Yoon, Joonseok;Yang, Hyukjun;Lim, Hojoon;Lee, Hyungcheol;Jeong, Changkil;Yun, Hyungjoong;Jeong, Beomgyun;Ethan, Crumlin;Lee, Juhan;Ju, Honglyoul;Mun, Bongjin Simon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.125.2-125.2
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    • 2015
  • The evolution of oxidation states of vanadium is monitored with ambient pressure X-ray photoemission spectroscopy. As the pressure of oxygen gas and surface temperature change, the formations of various oxidation states of vanadium are observed on the surface. Under 100mTorr of the oxygen gas pressure and 523K of sample temperature, VO2 and V2O5 are formed on the surface. The temperature-dependent resistance measurement on grown sample shows a clear metal-insulator transition near 350K. In addition, the measurement of Raman spectroscopy displays the structural change from monoclinic to rutile structures across the phase transition temperature.

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Transition of Silk Fibroin by Enzymatic Reaction (효소반응에 의한 견피브로인의 전이)

  • Kim, Dong-Keon;Choi, Jin-Hub;Konishi, Takashi
    • Journal of Sericultural and Entomological Science
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    • v.39 no.1
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    • pp.73-78
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    • 1997
  • The crystalline fraction of silk fibroin (Fcp) was obtained from the aqueous solution of silk fibroin hydrolyzed by $\alpha$-chymotrypsin. The molecular weight of Fcp was found approximately 7000 by using high speed GPC. On the other hand, a high molecular weight of PIFcp product could be obtained by the reverse reaction of enzymatic proteolysis of Fcp precipitates. Some parts of this PIFcp have the molecular weights of approximately 17000 and 24000. As a result of x-ray diffraction analysis, the crystal structure of Fcp and PIFcp was turned out silk-II type and silk-I type, respectively. Upon the reverse reaction of enzymatic protelysis, the structural transition occured from silk-II type to silk-I type crystal for the most of Fcp precipitates. It was confirmed that PIFcp might be somewhat stable crystal structure of silk-I type according to the thermal analysis as well as x-ray diffraction method.

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NMR Structural Study of the 3'-T.G Mismatched DNA Decamer Duplex Containing the T-T (6-4) Adduct

  • Lee, Joon-Hwa;Park, Yun-Jeong;Park, Byong-Seok
    • Journal of the Korean Magnetic Resonance Society
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    • v.3 no.1
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    • pp.60-70
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    • 1999
  • The pyrimidine(6-4) pyrimidone photoproduct [(6-4) adduct] is one of the major photoproducts induced by UV irradiation of DNA and occurs at TpT sites. The (6-4) adduct is highly mutagenic and specific during translesion replication. The marked preference for insertion of A opposite the 5'-T and G opposite the 3--T of the (6-4) adducts leads to a predominantly 3'-T\longrightarrowC transition with 85% replicating error rate. In order to obtain insight into the origin of 3'-T\longrightarrowC transition induced by the (6-4) adduct, we have performed one - and two-dimensional NMR experiment. The 3'-Tof the (6-4) lesion forms the stable hydrogen bonding to the imino proton of an opposed G, which stabilizes the overall helix and diminishes the highly distorted conformation caused by the (6-4) lesion in the (6-4)/AA duplex. We proposed that the greater insertion of a G over an A opposite the 3'-T of the (6-4) lesion These results may account for the greater preference for the insertion of a G over a A opposite the 3'-T of the (6-4) lesion. Thus this insertion leads to the highly specific 3'-T\longrightarrowC multation at the (6-4) lesion site.

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