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Internal structure of a massive star-forming region G33.92+0.11 revealed by the high resolution ALMA observations

  • Minh, Young Chol;Liu, H.B.;Chen, H.R.
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.44.2-44.2
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    • 2018
  • G33.92+0.11, classified as a core-halo UC HII region at a distance of 7.1 kpc, contains several sub-clumps (~20-200 solar masses) as identified by dust continuum emission. This source shows very complicated features associated with vigorous massive star-forming activities with a nearly face-on projection. The ambient gas is still accreting to the massive molecular clumps dynamically, while the whole cloud is under disruption by newly formed stars. Using the recent high resolution (< 0.2") ALMA observations, we investigate the detailed structure associated with the star-forming activities by comparing different chemical tracers. The sub-clumps having extremely complex morphologies still preserve cold dense gas together with the turbulent and dense warm gas resulted by newly formed stars and interaction with accreting gas. The accretion of the ambient gas may have occurred episodically to this source. Most recent star formation, which probably the third generation of star formation in this region, is taking place in the northern part (A5 clump). The relatively small mass (~ 1/3 of A1 or A2) and the lack of turbulent gas of this star-forming core may suggest that this core was formed already during the overall collapse of the whole cloud for the first star formation. We think that gravitational collapse of these sub-clumps appears as sequential star formation of this region. The later interaction with accreting gas may have not been a direct cause of the star formation activities of this source.

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A Study on the Fork Exhibition Hall as Eco-museum Core Center in Chungbuk Area (지역의 정보발신지로서 충북지역 향토민속자료전시관에 대한 연구)

  • Bang, Han-Young;Choi, Hyo-Seung
    • Journal of the Korean Institute of Rural Architecture
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    • v.5 no.2
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    • pp.20-32
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    • 2003
  • In this study, I grasped the actual conditions of folk exhibition hall in Chungbuk area. From this data I researched basically as the fundamental role of regional museum, eco-museum core center facilities, the connection with islanded and various inheritances, and central facilities whole area to the museum. And I could get following conclusion. First, on the studied result of folk exhibition hall in chungbuk area, it is not enough the activity of unearthing, collection, study etc. that is basic activity of the museum because the museum just permanently displayed historical contents of the area and simple life folk data. Second, add to existent museum concept and have to widen viewpoint to the museum which whole area is no roof, and utilize folk exhibition hall as the central facilities. Specially, there are a lot of difficulties to communicate information to visitors because of the absence of cultural heritance exponent. So a plan that local resident participate actively in museum activity may have to be considered. Third, the concept of inheritance limited in historical culture of area has to be widening by nature and industry etc. And we should keep up study that is the linked plan to scattered conservation remains, inheritance and tourist place in area.

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Utilization of Kenaf Cultivated in Korea (II) - Physical properties of kenaf TMP and KP - (국내산 Kenaf 이용에 관한 연구 (제2보) - Kenaf TMP와 KP의 물리적 성질 -)

  • Lee, Myoung-Ku;Yoon, Seung-Lak
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.39 no.4
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    • pp.45-52
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    • 2007
  • Whole, bast and core fibers of kenaf cultivar Tainung-2 were pulped under different pulping methods, thermomechanical and kraft pulping methods. The physical and optical properties of kenaf TMP(thermomechanical pulp) and KP(kraft pulp) handsheets were investigated and the results from the study are summarized as follows: Yields of TMP and KP were $77{\sim}87%\;and\;43{\sim}52%$, respectively. There was no significant change in apparent density between kenaf KP and USKP(unbleached softwood kraft pulp) but TMP showed a little lower apparent density. Bast pulp had the lowest apparent density regardless of pulping methods. Tensile strength of kenaf KP was higher than that of TMP but similar to that of USKP. Both TMP and KP handsheets of bast fraction showed the highest tear strengths among whole, bast, and core fractions. Core fraction showed the lowest tear strengths under different pulping methods. In general burst strength of kenaf pulp under different pulping methods was lower than that of USKP, and kenaf pulp had better stiffness than USKP. Brightness of kenaf KP and TMP was higher than that of USKP. There was no significant variation in opacity between kenaf pulp and USKP even though kenaf pulp showed a little lower opacity. The main difference in paper quality between the core fiber and bast fiber is derived from the fact that bast fiber is long and thin, whereas core fiber is short and thick.

Establishing a Core Collection of Proso Millet (Panicum miliaceum) Germplasm

  • Myung Chul Lee;Yu-Mi Choi;Myoung-Jae Shin;Hyemyeong Yoon;Kebede Taye Desta
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2020.08a
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    • pp.47-47
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    • 2020
  • The Korean National Agrobiodiversity Center holds the more than 1300 accessions of proso millet, but a large portion of accessions are landrace of Korea that has very similar traits. To comprehend the maximum genetic diversity of this crop, a core collection with minimum number of accessions will facilitate easy access to genetic material. Here we assessed the genetic diversity and population structure in a germplasm collection of 830 accessions by employing EST-SSR markers and morphological traits. A total of 107 alleles were detected with an average allele number of 4.9 per locus among the 830 accessions based on 37 EST-SSR markers. The number of alleles per locus ranged from 2 to 7. Polymorphism information content and expected heterozygosity ranged from 0.06 to 0.68 (mean = 0.21) and 0.06 to 0.73 (mean = 0.23), respectively. The germplasm collection was separated into two groups based on population structure analysis, whereas principal coordinate analysis (PCoA) could not cluster accessions according to their geographic origin. Subsequently, a preliminarily developed core collection with a total of 141 accessions (17%) was selected from the whole set of germplasm by combining allelic variations of EST-SSR markers and eight different phenotypic traits. The core collection optimally represented the whole germplasm collection and displayed a similar level of PCoA value and genetic variation from the initial collection. The results obtained here provide a primary resource for further genetic analysis and establish a reference for further development of appropriate genetic breeding strategies.

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Is There Any Immediate Difference between Pulmonary Function and Respiratory Muscle, with or without Vibration Stimulation in Respiratory Resistance Training? (진동 자극 유무에 따른 호흡 저항 훈련 시 폐 기능과 호흡근의 즉각적인 차이가 있을까?)

  • Park, Jin-Young;Kim, Ye-Seul;Park, Hyun-Ju;Lee, Myung-Mo
    • Journal of Korean Physical Therapy Science
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    • v.25 no.3
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    • pp.17-24
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    • 2018
  • Purpose: The purpose of this study was to investigate the effect of whole body vibration combined breathing resistance on lung capacity and respiratory muscle and to suggest a mediation method for improvement of respiratory function and lung function in the future. Methods: This study was a preliminary study design of two groups of 54 healthy young adults who were randomly assigned to an experimental group (n=27) with core exercise combined with respiratory resistance and whole body vibration and a control group with respiratory resistance and core exercise (n=27). All interventions consisted of 6 core exercises every 40 seconds and rest for 20 seconds. To compare the effects of intervention, we measured spirometry and respiratory muscle strength. Results: Both the experimental group and the control group showed a significant increase in Forced vital capacity (FVC) and Maximum voluntary ventilation (MVV) (p<.05). However, FEV1 and FEV1% were significantly increase only in the experimental group (p<.05). FVC, FEV1%, Maximum Inspiratory Pressure (MIP), Maximum Expiratory Pressure (MEP) showed more significant increase in the experimental group than the control group. Conclusion: These findings indicate that whole-body vibration combined breathing resistance is an effective intervention for people, with FVC, FEV1%, MIP, MEP increase.

Numerical Evaluation of the Cooling Performance of a Core Catcher Test Facility

  • Lee, Dong Hun;Park, Ik Kyu;Yoon, Han Young;Ha, Kwang Soon;Jeong, Jae Jun
    • Journal of Energy Engineering
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    • v.22 no.1
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    • pp.8-16
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    • 2013
  • A core catcher is considered as a promising engineered system to stabilize the molten corium in the containment during a postulated severe accident in a nuclear power plant. Conceptually, the core catcher consists of a carbon steel body, sacrificial material, protection material, and engineered cooling channel. The cooling capacity of the engineered cooling channel should be guaranteed to remove the decay heat of the molten corium. The flow in ex-vessel core catcher is a combined problem of a two-phase flow in the engineered cooling channel and a single-phase natural circulation in the whole core catcher system. In this study, the analysis of the test facility for the core catcher using the CUPID code, which is a three-dimensional thermal-hydraulic code for the simulation of two-phase flows, was carried out to evaluate its cooling capacity.

Validation of UNIST Monte Carlo code MCS using VERA progression problems

  • Nguyen, Tung Dong Cao;Lee, Hyunsuk;Choi, Sooyoung;Lee, Deokjung
    • Nuclear Engineering and Technology
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    • v.52 no.5
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    • pp.878-888
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    • 2020
  • This paper presents the validation of UNIST in-house Monte Carlo code MCS used for the high-fidelity simulation of commercial pressurized water reactors (PWRs). Its focus is on the accurate, spatially detailed neutronic analyses of startup physics tests for the initial core of the Watts Bar Nuclear 1 reactor, which is a vital step in evaluating core phenomena in an operating nuclear power reactor. The MCS solutions for the Consortium for Advanced Simulation of Light Water Reactors (CASL) Virtual Environment for Reactor Applications (VERA) core physics benchmark progression problems 1 to 5 were verified with KENO-VI and Serpent 2 solutions for geometries ranging from a single-pin cell to a full core. MCS was also validated by comparing with results of reactor zero-power physics tests in a full-core simulation. MCS exhibits an excellent consistency against the measured data with a bias of ±3 pcm at the initial criticality whole-core problem. Furthermore, MCS solutions for rod worth are consistent with measured data, and reasonable agreement is obtained for the isothermal temperature coefficient and soluble boron worth. This favorable comparison with measured parameters exhibited by MCS continues to broaden its validation basis. These results provide confidence in MCS's capability in high-fidelity calculations for practical PWR cores.

Design of the flexible switching controller for small PWR core power control with the multi-model

  • Zeng, Wenjie;Jiang, Qingfeng;Du, Shangmian;Hui, Tianyu;Liu, Yinuo;Li, Sha
    • Nuclear Engineering and Technology
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    • v.53 no.3
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    • pp.851-859
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    • 2021
  • Small PWR can be used for power generation and heating. Considering that small PWR has the characteristics of flexible operating conditions and complex operating environment, the controller designed based on single power level is difficult to achieve the ideal control of small PWR in the whole range of core power range. To solve this problem, a flexible switching controller based on fuzzy controller and LQG/LTR controller is designed. Firstly, a core fuzzy multi-model suitable for full power range is established. Then, T-S fuzzy rules are designed to realize the flexible switching between fuzzy controller and LQG/LTR controller. Finally, based on the core power feedback principle, the core flexible switching control system of small PWR is established and simulated. The results show that the flexible switching controller can effectively control the core power of small PWR and the control effect has the advantages of both fuzzy controller and LQG/LTR controller.