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Elevational Distribution of Breeding Bird Communities in Seoraksan National Park, Korea
( Hyun-su Hwang ),( Jae-kang Lee ),( Tae-kyung Eom ),( Ho-kyoung Bae ),( Dong-ho Lee ),( Jong-hwan Lim ),( Sung-cheol Jung ),( Chan-ryul Park ),( Shin-jae Rhim ) 한국산림과학회(구 한국임학회) 2020 한국산림과학회지 Vol.109 No.1
In this study, the elevational distribution of breeding birds in Seoraksan National Park, Korea was investigated. Forty-six species of birds were documented from line transect surveys taken from Seorakdong at 230 m above sea level (a.s.l.) to the Daechungbong summit at 1708 m asl. Birdspecies richness and diversity were highest in Seorakdong and lowest at the Daechungbong summit. As elevation increased, bird species richness and diversity decreased, with a humped-shape trend being observed between 700 m and 1200 m a.s.l. Stepwise analyses revealed that breeding bird species diversity indices were significantly negatively correlated with elevation (r<sup>2</sup> = 0.327, P < 0.001) and positively correlated with vegetational coverage (r<sup>2</sup> = 0.324, P = 0.046). Higher elevations supported fewer birds than low and intermediate elevations. Projections at the local scale, including data on behavior and habitat use by birds, will be necessary for optimal conservation and management of the bird communities in Seoraksan National Park.
Hyun Park,Woo‑Jin Lee,Jae‑Han Son,Han‑Kyun Shin,Sung‑Kyu Hong,Hyo‑Jong Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8
We introduce a cost-effective method that combines electroplating with metal cold working processes to manufacture compositetubes with robust corrosion resistance. First, a 3-step electroplating process was developed to form an adhesive anduniform Ag coating on the outer wall of a 304 stainless steel tube. The process consisted of a Ni-strike step for removing thepassivation layer of the initial 304 tube, Cu deposition for smoothing the surface by adding a buffer layer, and Ag deposition. To reinforce the interfacial adhesion between the electroplated layers and the 304 tube and increase the area of the Ag coating,a pilger rolling or pilger rolling + heat-treatment process was performed after the Ag electroplating process. Scanningelectron microscopy of the composite tubes after each process indicated that the as-deposited Ag coating changed fromhaving a rough to smooth surface after only pilger rolling and with additional heat treatment. Electron backscatter diffractionanalysis of the microstructures and textures of the tubes revealed that dynamic recrystallization occurred extensively duringpilger rolling, resulting in the formation of a relatively defect-free grain structure without heat treatment. Furthermore,electrochemical polarization curves determined that the Ag-coated composite tubes are superior to the uncoated 304 tubein terms of corrosion resistance under Cl−atmosphere, owing to the formation of a AgCl passivation layer during testing. Surface analysis of the composite tubes suggests that the properties of the AgCl passivation layer are related to the grainsize of the Ag coating and the density of plastic-deformation-induced defects.
박태근,김영환,박재현,박현민,최병석 明知大學校 産業技術硏究所 1999 産業技術硏究所論文集 Vol.18 No.-
In this paper, a new method of FEC(Forward Error Correction) using multi-stage Viterbi coder is proposed, with effectively reduce BER in satellite ATM Networks. In terms of structural complexity, proposed multi-stage Viterbi coder simpler than the traditional single-stage coder based on the same BER performances. And, through simulation, proposed coder shows excellent error correction capabilities compared with traditional FEC schemes. Also, we propose a selective FEC mechanism that adaptively changes the number of stages to satisfy the QoS(Quality of Service) requirements. This Selective scheme can be easily implemented using the PLCP(Physical Layer Convergence Protocol) frame structure.