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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.
Selective Deposition of Cobalt Oxide Thin Films via H<sub>2</sub>O-Vapor-Catalyzed Reaction
Kim, Dongbin,Roh, Ki-Min,Mun, Jihun,Jin, Yinhua,Lee, Sang Jun,Kim, TaeWan,Jeong, Soo-Hwan,Kim, Taesung,Kang, Sang-Woo American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.11
<P>In this study, we developed a method for realizing the selective deposition of CoO thin films using Co(hfac)(2) as a cobalt precursor and H2O vapor as a catalyst gas. Deposition on an insulator substrate can be controlled by varying the H2O flow rate. In order to study the gas-phase reaction, the concentration of generated particle was investigated as a function of the deposition temperature using an in-situ particle measurement system such as fourier transform infrared spectroscopy (FT-IR) to analyze the decomposition behavior of precursor and particle beam mass spectrometry (PBMS) to analyze the relationship between the precursor decomposition and the particle nucleation. Process temperature was controlled from 573 to 723 K with 50 K intervals. A gas cell was designed to analyze the decomposed precursor by FT-IR system, and its exhaust was connected with PBMS inlet to collect particles. Field-effect scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS) measurements were carried out to determine the film properties and its effects of H2O on catalytic reactions.</P>
Dielectric Properties of $Ta_2O_{5-X}$ Thin Films with Buffer Layers
Kim, In-Sung,Song, Jae-Sung,Yun, Mun-Soo,Park, Chung-Hoo The Korean Institute of Electrical Engineers 2002 KIEE International Transactions on Electrophysics Vol.12C No.4
The present study describe the electrical performance of amorphous T $a_2$ $O_{5-X}$ fabricated on the buffer layers Ti and Ti $O_2$. T $a_2$ $O_{5-X}$ thin films were grown on the Ti and Ti $O_2$ layers as a capacitor layer using reactive sputtering method. The X-ray pattern analysis indicated that the two as-deposited films were amorphous and the amorphous state was kept stable on the RTA(rapid thermal annealing) at even $700^{\circ}C$. Measurements of dielectric properties of the reactive sputtered T $a_2$ $O_{5-X}$ thin films fabricated in two simple MIS(metal insulator semiconductor), structures, (Cu/T $a_2$ $O_{5}$ Ti/Si and CuT $a_2$ $O_{5}$ Ti $O_2$Si) show that the amorphous T $a_2$ $O_{5}$ grown on Ti showed high dielectric constant (23~39) and high leakage current density(10$^{-3}$ ~10$^{-4}$ (A/$\textrm{cm}^2$)), whereas relatively low dielectric constant (~15) and tow leakage current density(10$^{-9}$ ~10$^{-10}$ (A/$\textrm{cm}^2$)) were observed in the amorphous T $a_2$ $O_{5}$ deposited on the Ti $O_2$ layer. The electrical behaviors of the T $a_2$ $O^{5}$ thin films were attributed to the contribution of Ti- $O_2$ and the compositionally gradient Ta-Ti-0, being the low dielectric layer and high leakage current barrier. In additional, The T $a_2$ $O_{5}$ Ti $O_2$ thin films exhibited dominant conduction mechanism contributed by the Poole-Frenkel emission at high electric field. In the case of T $a_2$ $O_{5}$ Ti $O_2$ thin films were related to the diffusion of Ta, Ti and O, followed by the creation of vacancies, in the rapid thermal treated thin films.films.
Rheological behavior of magnetic powder mixtures for magnetic PIM
Sung Hun Kim,김시조,박성진,Jun Ho Mun,강태곤,박장민 한국유변학회 2012 Korea-Australia rheology journal Vol.24 No.2
Powder injection molding (PIM) is a promising manufacturing technology for the net-shape production of small, complex, and precise metal or ceramic components. In order to manufacture high quality magnets using PIM, the magneto-rheological (MR) properties of the PIM feedstock, i.e. magnetic powder-binder mixture, should be investigated experimentally and theoretically. The current research aims at comprehensive understanding of the rheological characteristics of the PIM feedstock. The feedstock used in the experiment consists of strontium ferrite powder and paraffin wax. Steady and oscillatory shear tests have been carried out using a plate-and-plate rheometer, under the influence of a uniform magnetic field applied externally. Rheological properties of the PIM feedstock have been measured and characterized for various conditions by changing the temperature, the powder fraction and the magnetic flux density.
Effects of Drying Temperature on the $LiCoO_2$ Thin Films Fabricated by Sol-gel Method
Kim, Mun-Kyu,Park, Kyu-Sung,Kim, Duk-Su,Son, Jong-Tae,Kim, Ho-Gi The Korean Ceramic Society 2001 한국세라믹학회지 Vol.38 No.9
$LiCoO_{2}$ thin films have received attention as cathodes of thin film microbatteries in these days. In this study, $LiCoO_{2}$ thin films are fabricated by a sol-gel spin coating method followed by a post-annealing process. The thermal decomposition behaviour of precursor is investigated by TG/DTA analysis. The change of crystallinity, microstructure and electrochemical properties of final films as the drying temperature changes are also studied by XRD, SEM and galvanostatic charge/discharge cycling test. The relationship between the discharge capacity and the drying temperature are intensively investigated in this work.
Terahertz Time Domain Spectroscopy, T-Ray Imaging and Wireless Data Transfer Technologies
Mun Cheol Paek,Min Hwan Kwak,Seung Beom Kang,Sungil Kim,Han-Cheol Ryu,Sang Kuk Choi,Se Young Jeong,Dae Won Kang,Dong Suk Jun,Kwang Yong Kang 한국전자파학회JEES 2010 Journal of Electromagnetic Engineering and Science Vol.10 No.3
This study reviewed terahertz technologies of time domain spectroscopy, T-ray imaging, and high rate wireless data transfer. The main topics of the terahertz research area were investigation of materials and package modules for terahertz wave generation and detection, and setup of the terahertz system for time domain spectroscopy(TDS), T-ray imaging and sub-㎔ wireless communication. In addition to Poly-GaAs film as a photoconductive switching antenna material, a table-top scale for the ㎔-TDS/imaging system and terahertz continuous wave(CW) generation systems for sub-㎔ data transfer and narrow band T-ray imaging were designed. Dielectric properties of ferroelectric BSTO(BaxSr1-x TiO₃) films and chalcogenide glass systems were characterized with the ㎔-TDS system at the ㎔ frequency range. Package modules for terahertz wave transmitter/receiver(Tx/Rx) photoconductive antenna were developed.
Kim, Sang-Mun The Korean Ceramic Society 2003 한국세라믹학회지 Vol.40 No.2
To reduce the doming of the shadow mask due to thermal expansion and to prevent the color discrepancy, the electron reflecting layer with lead tungsten oxides on the electron gun side of shadow mask was formed by screen printing method and doming property was evaluated in CRT. First, the lead tungsten oxides were prepared by calcining the mixture of lead oxide and tungsten oxide above 600$^{\circ}C$. Second, the paste which has the anti-doming composition including the lead tungsten oxides was coated by screen-printing method. As a result, the doming of the shadow mask was reduced about from 30 to 45%.
Characteristics of NOx and PM2.5 Concentrations in Underpass Sections
Kim Moonkyung,Lee Jong Won,Lee Sang Hyuk,Park Hee Mun 한국도로학회 2020 한국도로학회논문집 Vol.22 No.3
PURPOSES : The objective of this study is to figure out the trend and characteristics of fine particulate matter (PM2.5) and nitrogen oxide (NOx) concentration in underpass sections. The effect of traffic and meteorological condition on PM2.5 / NOx concentration was analyzed using field monitoring data. METHODS : Based on the literature review, PM2.5 and NOx concentration data were monitored using DustTrak II aerosol monitoring system and Serinus 40 oxides of nitrogen analyzer, respectively. Meteorological and traffic information was collected using automatic weather system and traffic volume counter, respectively. RESULTS : PM2.5 has a positive and negative correlation with relative humidity and wind speed, respectively. Meanwhile, NOx was found to have no correlation with meteorological conditions. The NO/NO2 ratio tends to change with traffic volume, indicating higher correlation between NO and traffic volume; the observed NO2 is mostly a secondary material produced by NO oxidation. CONCLUSIONS : Our study provides clear characteristics of NOx and PM2.5 and correlations with meteorological and traffic information in the underpass sections. It is found from this study that the increase in wind speed causes reduction in the concentration of PM2.5 owing to the diffusion and dispersion phenomena. On the other hand, the meteorological conditions were found to barely have correlations with NOx concentrations in this study. The traffic volume could significantly affect the NOx concentration and NO / NO2 ratio, which is directly correlated to the emissions from vehicles.