• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.169-174
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• 1997

This study was conducted to obtain basic information needed to develop the effective weed control method by using thermal weeder which uses LPG as fuel. For survey of weed distribution in herb field, weed species were investigated at two kinds of herb field of Codonopsis lanveolata and Aster scaber located in Hoengseongkun and Hwacheonkun, Kangwondo. In Codonopsis lanveolata field, Digitaria sanguinalis and Persicaria viridis L were dominated. In Aster scaber field, Digitaria sanguinalis and Erigeron canadensis were dominated. In general, Grasses weeds in herb were more dominated than other broadleaf and Cyperaceae weeds. The treatments of $H_2SO_4$ in weed seeds were more effective for germination of several weeds, compared with that nontreated weed seeds. However, the rate of germination differed depending on weed species and tereatment time of $H_2SO_4. Also, viability of weed seeds was significantly affected by irradiation time and temperature. As the temterature and treatment time of irradiation increased, the rate of germination was decreased.

• Korean Journal of Plant Taxonomy
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• v.39 no.1
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• pp.48-54
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• 2009

We investigated the genetic diversity of an endemic rare species, Forsythia ovata Nakai by examining 93 ISSR amplicons in 84 individuals distributed among five populations. The overall percentage of polymorphic ISSR amplicons was 54.8% and mean number of amplicons per ISSR primer was 6.6. The amount of genetic diversity was relatively lower than other shrub species. The Mt. Seokbyeong and Mt. Seorak B populations had the highest level of genetic diversity. Although the Seokgae-jae population had the lowest level of genetic diversity, the population was genetically the most distinctive from the other populations. About 30.6% of the total variation was allocated between five populations, which was slightly higher than other shrub species. Such a pattern of genetic variation may have resulted from the limited distribution and small population sizes of F. ovata. The UPGMA dendrogram based on Nei's genetic distance showed some decisive geographic patterns. These results suggest that, in addition to the preservation of the natural stands, the conservation of larger number of populations with small number of individuals per population is more effective for the dynamic ex situ conservation and for maintaining the genetic diversity of F. ovata than smaller number of populations with large number of individuals.

• Korean Journal of Plant Taxonomy
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• v.43 no.4
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• pp.274-284
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• 2013

This study presents a survey on the bryophytes in Dongbaek-dongsan located at Seonheul Gotjawal on the north-eastern face of Mt. Halla in Jeju Island, Korea. A total of 85 taxa belonging to the Bryophyta (22 families 44 genera 62 species), Marchantiophyta (12 families 16 genera 23 species) were found. Among them, 3 moss species, Diphyscium perminutum Takaki, Racomitrium japonicum Dozy & Molk., and Isopterygium minutirameum (M$\ddot{u}$. Hal.) A. Jaeger. were new additions to the bryophyte flora of Korea. The liverwort index was 27.0%. Predominant life-form was weft. The rates for the bryophytes dominating in mesic to hygric sites were higher than for the bryophytes mainly observed in xeric habitats. We considered that the composition and distribution of species are affected by the different environmental factors according to the evergreen broad-leaved forests, wetlands and exposed spaces. Moreover, the rocks were the substrate type that play a major role in providing the micro-habitats for bryophytes in this area. Particularly, the bryophytes of swamps in this area were very unique and various for its limited space and showed plant communities with mosaic spatial pattern, along with vascular plants. We suggest more detailed and comprehensive studies on the swamps where endemic fern Mankyua chejuense B. -Y. Sun, M. H. Kim & C. H. Kim inhabits to provide valuable information for the conservation and restoration of the species and habitats.

• Korean Journal of Plant Taxonomy
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• v.43 no.2
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• pp.128-138
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• 2013

The conservation status of an endemic perennial herb, Hanabusaya asiatica (Nakai) Nakai (Campanulaceae) was determined by applying the IUCN risk assessment criteria from our field study and available specimen data. Also, the GIS technology was used to develop a species distribution map to calculate the extent of occurrence (EOO) and area of occupancy (AOO) for the taxon. After two years of continuous field studies, 269 mature individuals were found in four localities in 2011, while 216 mature individuals were confirmed in three localities in 2012. Based on the following data, such as EOO (2,742 $km^2$), AOO (76 $km^2$) and estimated population size of mature individuals, the taxon, which is known as 20 localities in Korean peninsula, is evaluated as the category of Endangered (EN). A major difficulty in application of IUCN criteria to Korean rare plants were the lack of essential biological information and understanding the correct knowledge of the IUCN criteria in previous Korean studies. Sound conclusions regarding the conservation status of individual species require more intensive population studies, observations, and applying IUCN assessment procedures correctly.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.94-98
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• 2005

This study was carried out to provide the geographic information based on the distribution of rice qualities and palatability in Gyeoungbuk province of Korea. The rice grain quality and environmental factors were analyzed using 513 sampling sites based on different five-agroclimtic regions of Gyeoungbuk province during three years from 2002 to 2004. In rice grain quality characteristics, the average palatability was low in South eastern coastal and Tabaek semi alpine regions as $67.6\~68.3$ and the coefficient of variation (CV) was relatively high as $6.2\~7.4\%$. The average head rice rates were low in South and Central eastern coastal regions as $87.3\~88.2\%$ and CV was high as $8.2\~8.3\%$. The average protein content was high in Central eastern coastal regions as $8.0\%$ and CV was high as $8.2\~8.3\%$. In case of palatability, the variation was differed clearly between high and low agroclimatic regions; it means that it is possible to divide the same agroclimatic region of high CV into two or three areas by CV of palatability. As the results of subdividing each existing agroclimatic regions based on the palatability, the variation of grain quality characteristics was become lower than that of existing five-agroclimatic regions. Therefore, the re-establishing of agroclimatic region based on rice grain quality was very important for precise cultivation for rice.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.251-258
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• 2016

This article reports current status of micro fuel cell-combined heat and power (${\mu}FC$-CHP) systems which utilize both power and heat generated by fuel cells. There are several options for constructing CHP systems and among them, fuel cells are the most useful and their total energy efficiency combining heat and power can reach up to about 90%. Fuel cells are classified as five types based on the electrolyte, but the most suitable fuel cell types for the ${\mu}FC$-CHP system are proton exchange membrane fuel cells (PEMFCs) and solid oxide fuel cells (SOFCs). ${\mu}FC$-CHP systems have several advantages such as decrease of the transmission-distribution loss, reduced costs of electricity due to distributed power generation, and environmental-friendliness owing to zero emission. The main drawback of the ${\mu}FC$-CHP systems is the high initial investment, however, it keeps decreasing as the technology development reduces production costs. Currently, Japan is the most leading country of the ${\mu}FC$-CHP market, however, Korea tries to expand the market by planning the deployment of 1 million units of ${\mu}FC$-CHP systems and governmental subsidiary supporting of half of the install price. In this report, integration technologies for connecting FC and CHP, and technology trends of leading countries are presented as well.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.1
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• pp.53-69
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• 2015

Plants and birds have symbiotic relationship as the birds eat the fruits and disperse its seeds from the different places. Because Brown-eared Bulbul eats various fruits, We investigated the fruits consumed by Brown-eared Bulbul and the distribution of these seeds. Surveys were conducted at several area throughout Jeju Island at least twice a month from 2013 to 2014. We identified the fruits consumed by Brown-eared Bulbul through observation, pictures and interviews from the local residents. Results showed that this species consumed fruits from 82 plant species, belonging to 38 plant families. Thirty nine percent(39%) of these plant species belong to the Rosaceae, Lauraceae, Moraceae, Aquifoliaceae and Vitaceae and 33 species were classified as warm-temperate and subtropical plant which is 40% of the total plant species consumed. Two feeding types, which were gulper type and pecking type were observed for the Brown-eared Bulbul. It was also observed that this species preferred eating fruits of gulping type compared to that of pecking type. The average size of the fruits consumed through gulping was $8.92{\pm}3.41mm$ while it was $45.25{\pm}26.67mm$ for the pecker type. This bird species also consumed more fruits with globular shape compared to those of fruits with ellipse shape. For the fruit color, red and black-colored fruits were more preferred than yellow-colored fruits by Brown-eared Bulbul. Eaten frequency varied from 0.04 to 0.58 and the 10 fruits species were eaten frequently by Brown-eared Bulbul. This study would provide information for the role of Brown-eared Bulbul in the ecosystem as a seed dispersal agent.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.309-323
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• 2020

Estimation of chlorophyll a concentration (CHL) on coastal areas using remote sensing has been mostly performed through multi-spectral satellite image analysis. Recently, various studies using hyperspectral imagery have been attempted. In particular, airborne hyperspectral imagery is composed of hundreds of bands with a narrow band width and high spatial resolution, and thus may be more effective in coastal areas than estimation of CHL through conventional satellite image. In this study, comparative analysis of hyperspectral and satellite-based CHL images was performed to estimate CHL in coastal areas. As a result of analyzing CHL and seawater spectrum data obtained by field survey conducted on the south coast of Korea, the seawater spectrum with high CHL peaked near the wavelength bands of 570 and 680 nm. Using this spectral feature, a new band ratio of 570 / 490 nm for estimating CHL was proposed. Through regression analysis between band ratio and the measured CHL were generated new CHL empirical formula. Validation of new empirical formula using the measured CHL showed valid results, with R² of 0.70, RMSE of 2.43 mg m^-3, and mean bias of 3.46 mg m^-3. As a result of applying the new empirical formula to hyperspectral and satellite images, the average RMSE between hyperspectral imagery and the measured CHL was 0.12 mg m^-3, making it possible to estimate CHL with higher accuracy than multi-spectral satellite images. Through these results, it is expected that it is possible to provide more accurate and precise spatial distribution information of CHL in coastal areas by utilizing hyperspectral imagery.

• Progress in Superconductivity
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• v.7 no.1
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• pp.28-35
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• 2005

We propose a method to measure atrial arrhythmias (AA) such as atrial fibrillation (Afb) and atrial flutter (Afl) with a SQUID magnetocardiograph (MCG) system. To detect AA is one of challenging topics in MCG. As the AA generally have irregular rhythm and atrio-ventricular conduction, the MCG signal cannot be improved by QRS averaging; therefore a SQUID MCG system having a high SNR is required to measure informative atrial excitation with a single scan. In the case of Afb, diminished f waves are much smaller than normal P waves because the sources are usually located on the posterior wall of the heart. In this study, we utilize an MCG system measuring tangential field components, which is known to be more sensitive to a deeper current source. The average noise spectral density of the whole system in a magnetic shielded room was $10\;fT/{\surd}Hz(a)\;1\;Hz\;and\;5\;fT/{\surd}Hz\;(a)\;100\;Hz$. We measured the MCG signals of patients with chronic Afb and Afl. Before the AA measurement, the comparison between the measurements in supine and prone positions for P waves has been conducted and the experiment gave a result that the supine position is more suitable to measure the atrial excitation. Therefore, the AA was measured in subject's supine position. Clinical potential of AA measurement in MCG is to find an aspect of a reentry circuit and to localize the abnormal stimulation noninvasively. To give useful information about the abnormal excitation, we have developed a method, separative synthetic aperture magnetometry (sSAM). The basic idea of sSAM is to visualize current source distribution corresponding to the atrial excitation, which are separated from the ventricular excitation and the Gaussian sensor noises. By using sSAM, we localized the source of an Afl successfully.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.445-453
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• 2010

This study was conducted to investigate herbicidal efficacy and diffusibility of halosulfuron-methyl+mefenacet in water treated with 500 g great granule (GG) and 3 kg granule (GR). The 500 g GG was been spreading on the surface of the water within 6 minutes, 53 seconds, and it's active ingredient was diffused in the water bath of $10m^2$ size between 30 and 60 minutes. In addition, the diffusion of 500 g GG was influenced by moisture contents, so it have to immediately use 500 g GG in paddy fields when it was been unpacked. The herbicidal efficacy of the 500 g GG and 3 kg GR of halosulfuron-methyl+mefenacet was excellent to most weed species, but showed different efficacy for the control of Aneilema keisak and Scirpus juncoides, that was may be distribution pattern of active ingredient as different formulation.