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종 분포 모형을 이용한 구상나무림의 지속 및 쇠퇴에 관한 연구 - 전라남도 광양시 백운산을 중심으로 -
조선희 ( Seon Hee Cho ),박종영 ( Jong Young Park ),박정호 ( Jeong Ho Park ),이양근 ( Yang Geun Lee ),문이만 ( Lee Man Mun ),강상호 ( Sang Ho Kang ),김광현 ( Gwang Hyun Kim ),윤종국 ( Jong Guk Yun ) 한국산림과학회 2015 한국산림과학회지 Vol.104 No.3
The present study investigated the habitats of Korean fir trees (Abies koreana E. H. Wilson) on Mt. Baekwun (Baekwun-san), determined the current distribution, quantified the contribution of biological and nonbiological environmental factors affecting the distribution, derived actual and potential habitats, presented a plan for the establishment of protected areas, applied RCP 8.5 climate change scenario to analyze the effects of climate change on the future distribution of Korean fir trees, and predicted future potential habitats. According to the results of the study, 3,325 Korean fir trees (DBH >= 2.5 cm) inhabited Mt. Baekwun, and their distribution area was approximately 150 ha. Populations of Korean fir trees were confirmed to exist at an altitude of 900 m above sea level and were distributed up to 1,200 m. Based on potential distribution, areas appropriate for habitation by Korean fir trees were analyzed to be 450 ha, three times the current distribution area, with a focus on Sang Peak (Sang-bong), Eokbul Peak (Eokbul-bong), Ddari Peak (Ddari-bong), and Dosol Peak (Dosol-bong). The forest stands near Sang Peak, the main peak, were evaluated as those with the most appropriate potential for the habitation of Korean fir trees, and populations of the trees tended to prefer the northern slope rather than the southern slope. When climate change scenario RCP 8.5 was applied and future potential distribution was analyzed, the habitats were expected to decrease in area to 20 ha by 2050, with a focus on Sang Peak, and areas appropriate for habitation were predicted not to exist by 2080. Judging from such results, as global warming accelerates, the habitats of Korean fir trees are clearly expected to move from lowlands to highlands.
Yun, Yang Sik,Lee, Minzae,Sung, Jongbaek,Yun, Danim,Kim, Tae Yong,Park, Hongseok,Lee, Kyung Rok,Song, Chyan Kyung,Kim, Younhwa,Lee, Joongwon,Seo, Young-Jong,Song, In Kyu,Yi, Jongheop Elsevier 2018 Applied Catalysis B Vol.237 No.-
<P><B>Abstract</B></P> <P>Ce-incorporated MoVTeNbO catalysts were developed to enhance ethylene productivity of oxidative dehydrogenation of ethane (ODHE) to ethylene. Structural characterizations (XRD, TEM, STEM, Raman, and UV–vis DRS) and DFT calculations revealed that Ce atoms were incorporated into MoVTeNbO framework with maintaining its unique structure (<I>M1</I> phase), which is active phase for ODHE. The reducibility of the catalysts was enhanced and both V<SUP>5+</SUP> and the lattice oxygen species available to ODHE reaction were enriched by incorporation of Ce, confirmed by TPR, XPS, and pulse injection method, respectively. These improved properties enhanced the conversion of ethane while maintaining their excellent selectivity to ethylene for MoVTeNbCeO catalysts. It is noteworthy that 56.2% of ethane conversion and 95.4% of ethylene selectivity were retained for 200 h over MoVTeNbCeO-0.1 catalyst. Ethylene productivity was calculated to be 1.11 kgC<SUB>2</SUB>H<SUB>4</SUB>/kg<SUB>cat</SUB> h. The developed catalyst exhibits substantial level of ethylene productivity and stability having the possibility with low production of CO<SUB>x</SUB> to make a step forward for industrialization of oxidative dehydrogenation of ethane.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ce incorporated MoVTeNbO catalyst is synthesized by hydrothermal method. </LI> <LI> Various characterizations and DFT calculations prove incorporation of Ce. </LI> <LI> Incorporated Ce induces enrichments in fraction of V<SUP>5+</SUP> and lattice oxygen capacity. </LI> <LI> Enhanced catalytic activity was observed by incorporated Ce than catalyst without Ce. </LI> <LI> MoVTeNbCeO-0.1 shows excellent ethylene productivity and selectivity with stability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Safety and Efficacy of Selective Intra-arterial Thrombolysis for Central Retinal Artery Occlusion
Sang Jun Ko,In Choel Shin,Dae Won Kim,Si Sung Choi,Yun Sik Yang 대한안과학회 2021 Korean Journal of Ophthalmology Vol.35 No.4
Purpose: The purpose of this study was to determine the efficacy and safety of selective intra-arterial thrombolysis in patients with central retinal artery occlusion (CRAO). Methods: Medical records for 44 eyes of 44 patients diagnosed with acute non-arteritic CRAO and thrombolysis between October 2010 and February 2019 were analyzed retrospectively. Based on visual acuity, fundoscopic findings, and fluorescein angiography, the patients were classified into three stages: incomplete, subtotal, and total. The perfusion state using the best-corrected visual acuity (BCVA), arm to retina time, and arteriovenous passage times, after 1 month, 6 months, and at the final visit after the procedure, were compared with baseline readings. Results: Improvement of visual acuity was confirmed in 31 out of 44 patients (70.45%). The mean BCVA of 44 patients changed from 1.65 ± 0.78 logarithmic minimum angle of resolution (logMAR) at the first visit to 1.18 ± 0.91 logMAR at the last visit (p = 0.114). The BCVA according to CRAO stage was 0.08 ± 0.11 logMAR for the incomplete stage at the first visit, 0.06 ± 0.05 logMAR (p = 0.933) 1 month after the procedure, and 0.05 ± 0.07 logMAR (p = 0.933) at the last visit. In the subtotal stage, the results were 1.81 ± 0.54 logMAR at the first visit, 1.63 ± 0.76 logMAR (p = 0.035) 1 month after the procedure, and 1.36 ± 0.85 logMAR (p = 0.014) at the last visit. For the total stage of BCVA, the result at the first visit was 2.36 ± 0.25 logMAR, and it was 2.30 ± 0.30 logMAR (p = 0.510) 1 month after the procedure, and 2.42 ± 0.30 logMAR (p = 0.642) at the last visit. Reperfusion was observed in 40 patients out of the 44 (90.91%). Conclusions: Selective intra-arterial thrombolysis can be helpful in patients with subtotal CRAO in terms of visual improvement and retinal arterial reperfusion.
Kinetics of Complexation of Alkali Earth Metal Ions with 18-Crown-6-Ether in Methanol
Yun, Sock-Sung,Kim, Seong-Heon,Yang, Joon-Mook,Choi, Ki-Young Korean Chemical Society 1989 Bulletin of the Korean Chemical Society Vol.10 No.2
The rates of complexation of the 18-C-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) with $K^+,\;Ca^{2+},\;Sr^{2+},\;and\;Ba^{2+}$ in methanol solution have been determined at 25$^{\circ}C$ by a pressure-jump technique. The Eigen Winkler mechanism has been applied to interprete the kinetic data. The results suggest that the rate determining step of the complexation in methanol is the rearrangement of the ligand in the outer sphere ion-dipole pair to form a stable encapsulated complex of the metal ion by the crown ether.
Survival and In Vitro Development of Immature Bovine Oocytes Cryopreserved by Vitrification
Yang, Byoung-Chul,Im, Gi-Sun,Chang, Won-Kyong,Lee, Yun-Keun,Oh, Sung-Jong,Jin, Dong-Il,Im, Kyong-Sun,Lee, Chang-Kyu Asian Australasian Association of Animal Productio 2003 Animal Bioscience Vol.16 No.1
The present study was undertaken to investigate the effects of PVP concentration and exposure temperature to vitrification solution on the post-thaw survival, in vitro maturation and development of immature bovine oocytes (germinal vesicle stage). The vitrification solution (VS) consisted of 40% ethylene glycol (EG)+0.5 M sucrose (S)+10% FBS. PVP was added to VS: 0%, 5% or 10%. The cumulus-oocyte complexes (COCs) were diluted in VS as one step, after 2 min the COCs were loaded in straw and vitrified by direct immersion into liquid nitrogen. For thawing, the straws were plunged into $30^{\circ}C$ water bath for 10s. After thawing, the oocytes were diluted in 0.5 M (in DPBS with 10% FBS) sucrose solution for 5 min. The survival rate (FDA-test and trypan blue) of immature bovine oocytes was measured. The survival rate was higher in 5% PVP (91.5%) than in 0% (64.2%) or in 10% PVP (79.7%). The proportion of metaphase II formation was 69.35% in control (no vitrified COCs), 9.3% in 40% EG+0.5 M S+0% PVP and 21.05% in 40% EG+0.5 M S+5% PVP (p<0.05). The effect of room temperature ($25^{\circ}C$ for 10 min) and cold temperature ($4^{\circ}C$ for 10 min) on COCs were determined in this study. After IVF, the cleavage and blastocysts rate of oocytes exposed to room temperature and cold temperature in VS+5% PVP was significantly different (2 cell: 63.20% vs 37.97%, blastocysts: 18.40% vs 2.53%). The cleavage rates of frozen-thawed oocytes were 20.53% with PVP and 22.13% without PVP (p>0.05). Two out of 151 oocytes (1.32%) developed to blastocyst stage after frozen-thawed with 5% PVP (p>0.05). Development of oocytes after frozen-thawing to the 2 cell were not significantly affected with or without PVP following IVF. However, the vitrification of immature bovine oocytes with PVP maintained the ability to develop to the blastocyst stage after IVM-IVF and IVC, while no blastocysts were obtained from oocytes vitrified without PVP. These results suggested that PVP has a protective role for vitrification of immature bovine oocytes as far as survival is concerned, however, the protection was not sufficient enough to support blastocyst formation.
A Practice of Developing New Environment-friendly System by Composites
Yun-Hae Kim,Dong-Hun Yang,Young-Dae Jo,Seung-Jun An,Se-Ho Park,Sung-Won Yoon 한국공학교육학회 2010 공학교육연구 Vol.13 No.5
This study intends to study about the blade performance loss occurred due to the variation in the shape of an airfoil from attachment/non-attachment of an erosion shield for the hovercraft. The model in this study has used NACA44XXseries, has designed NACA44XX-series by using the Auto CAD, and it designed the shape that has attached an erosion shield to this model according to the thickness and length. By using these models, a grid was generated by GAMBIT and the lift coefficient (C l ) and the drag coefficient (C d ) were calculated FLUENT code for flow analysis. Through this, the C l and C d have calculated and compared the lift-to-drag ratio that an indicator of airfoil performance according to the shape and attachment/non-attachment of erosion shield.
Antenna Modeling Using Sparse Infinitesimal Dipoles Based on Recursive Convex Optimization
Yang, Sung Jun,Kim, Young Dam,Yun, Dal Jae,Yi, Dong Woo,Myung, Noh Hoon IEEE 2018 IEEE antennas and wireless propagation letters Vol.17 No.4
<P>Infinitesimal dipole modeling (IDM) can model antennas analytically with small amounts of data. Constrained IDM has been proposed to improve the modeling efficiency by fixing the positions and orientations of the dipole elements. The restrictions have a tradeoff of the modeling requiring more dipole elements. Therefore, the modeling technique has the disadvantage of having low practicality. A recursive convex optimization based on reweighted <I>l</I><SUB>1 </SUB>-norm is proposed for sparse IDM. By applying the reweighted <I>l</I><SUB>1</SUB>-norm to the convex optimization, the IDM can represent sparse solutions. Antennas can be modeled with dipole elements less than half of the previous constrained IDM. For verification, a five-patch array antenna and a slot array antenna are modeled by the proposed IDM scheme. About 57% and 45% of the dipole elements can be respectively suppressed using the proposed algorithm, with only 1 dB degradation in modeling accuracy.</P>