• Journal of the Korean earth science society
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• v.31 no.4
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• pp.313-321
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• 2010

The landform of the study area is defined as a small-scale alluvial plain in the valley bottom adjacent to the coast. By the aggradation of alluvial materials, this valley bottom plain was formed in dissected parts of low hills. For the purpose of reconstructing the palaeo climate environment in this study, $\delta^{13}C$ analysis and soil organic carbon analysis are therefore employed. Main results of this study are as follows: Section I: the period of $6,600{\pm}60yr$ B.P.$-5,350{\pm}60yr$B.P. was mostly in warm and humid climate environment. A little changes of the humid environment are detected as subdry (or sub-humid)${\rightarrow}$humid in terms of the dryness and wetness. Section II: the period of $5,350{\pm}60yr$ B.P.-2,200 yr B.P. was in warm and humid climate environment, which is similar to the present. However, The sediments between $4,720{\pm}60yr$ B.P. and $4,210{\pm}50 yr$ B.P. experienced the most humid climate environment of all studied sedimentary layers. After $4,210{\pm}50 yr$ B.P., the environment started to change from the humid to the sub-humid (or sub-dry) climate. Section III: the period of 2,200 yr B.P.$-210{\pm}60 yr$ B.P. was distinguish from previous two sections as the environmental changes to sub-humid (or sub-dry) climate was apparent.

• Journal of the Korean GEO-environmental Society
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• v.3 no.2
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• pp.35-47
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• 2002

Soil and rock were yielded during construction of subway in Taegu. Produced rock is a kind of a sedimentary rock with low strength and low durability of shrinkage. So it is difficult using for resources engineering. But in our country, it is very important to use material resources due to lack of natural resources. In this study, after cracking sedimentary rock like black shale and red shale, they are compared with granite which usually used road constriction field to investigate property of use for road construction. Consequently, the engineering character of origin rock is satisfactory, but the soundness test, black shale and red shale are less than KS 12.9%, 37.5% respectively. The result of concrete freezing-thawing test shows that the strength among three materials is not a wide difference but red shale has relatively low strength. The result of asphalt freezing-thawing test with 50 cycles indicates that the stability of red shale in lower than KS 484~561kg on base course, 336~375kg on surface course respectively. A further research should be needed for propriety to the material of shale.

• Journal of Environmental Science International
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• v.17 no.3
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• pp.287-296
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• 2008

A comprehensive quality survey for heavy metals, organophosphorous and organochlorine residual pesticides, and coplanar PCBs in samples such as water, sediments and soils as well as spiders has been implemented. The samples were undertaken at nine stream sites and their vicinity in August 2006, representing different surrounding environments. The levels of PCBs were expressed as concentrations and WHO-TEFs. Among 12 coplanar PCBs as target compounds in this study, 2,3', 4,4', 5-PentaCB (IUPAC # 118) was the congener with the highest concentration. The total concentrations and TEF values of coplanar PCBs in Siheung stream sediment (heavy industrial complex site located in Ansan city) were 3915.50 pg/g and 0.8366 pg-TEQ/g on a dry weight basis, respectively. Such levels were around 40 times higher compared to sediment from Gapyung stream (green site located in the upper of Myunggi mountain). It is probably due to the direct input of PCBs trom PCBs treatment materials. Organophosphorous (EPN, dementon-s-methyl, diazinon, parathion, and phenthoate) and organochlorine (alpha-BHC, aldrin, 4,4'-DDT, 4,4'-DDE, endosulfan alpha and etc.) pesticides were not detected above 5 ppb of detection limits. The concentrations of Cu and Cd in water and sediment samples from Siheung stream were 44.11 and $0.17ug/m\ell$ and $713.42{\mu}g/g$ and $3.73{\mu}g/g$, respectively, which contained $20\sim40$ times higher concentrations than those from Gapyung stream. In addition to the water and sediment samples, the levels of heavy metals in spider from designated sampling sites were also determined. Heavy metals in spider collected near Siheung stream was appeared to be equivalent and/or a little higher levels with respect to other spiders. Furthermore, the ratio of relative heavy metals (Cu, Cd, and Pb) in spider from each stream site showed a correlation as similar as that of heavy metals in soil samples.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1479-1487
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• 2013

The river levee collapse and flood damages are dramatically increased due to the floods which caused by abnormal weather nowadays. The counterplan like TDR(Time Domain Reflectometry) river levee leaking exploration technique is needed to that levee failure causes of levee failure such as levee failure by penetration, piping, inadequate levee materials selection, poor compaction are almost 52% of the failure. This research practiced various comparing experiments of existing TDR(probe and tube types) and developing CAP type TDR to evaluate acrylic small CAP mould and low-cost TDR levee leaking monitoring system which was used probe type TDR. As the result, evaluated TDR system had 20cm critical exploration performance which was a leaking exploration performance, The functional ratio of TDR exploration sensitivity of dry density was sensitive more than 3 times than dry density, and weathered granite soil foundation water contents(w)-dielectric constant(${\epsilon}$) corelation formula was suggested to measure functional ratio on developing cap type TDR system.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.11-17
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• 2007

Previously developed transgenic watermelon rootstocks (gongdae) inserted by CGMMV-CP were examined to test the virus tolerance levels. In the restricted plastic house, the $T_{3}$ watermelon rootstock showed tolerance to CGMMV until 70 days after inoculation on the leaves while the non-transformed watermelon rootstock became susceptible at 20 days after inoculation. In the field, tolerance efficiency of transgenic rootstocks maintained up to 40% at 71 days after contamination with CGMMV in the soil while all of the non-transformed rootstocks became susceptible at 37 days with the same condition. In the same field, transgenic rootstocks showed more tolerance to CGMMV than the non-transformed rootstocks as those were inoculated on the leaves, but it showed only 10 days delay before being susceptible. Therefore, transgenic rootstocks have a characteristic of delay effect against CGMMV susceptibility, rather than resistance character. From $T_{3}$ rootstocks homozygous for the CGMMV-CP horticulturally favorable individuals were selected for further breeding and a transgenic line was finally obtained at the $BC_{1}T_{5}$. A material transfer experiment was conducted to find out if the DNA, RNA or expressed protein in the transgenic rootstocks could move to the grafted scion (non-transformed watermelon, Super-Kumcheon). PCR, northern, and western blot analysis were performed and no evidence of transferring of those materials from rootstock to scion was ever found.

• Research in Plant Disease
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• v.17 no.2
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• pp.121-128
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• 2011

Bacteriolytic myxobacteria have been known to secrete various antifungal metabolites against several soilborne phytopathogens including Phytophthora. Among the three isolates of Myxococcus spp., KYC 1126 and KYC 1136 perfectly inhibited the mycelial growth of Phytophtora capsici in vitro. In order to show the biocontrol activity on Phytophthora blight of hot pepper, we tried to find the best way of application of a myxobacterial isolate. Although KYC 1126 fruiting body was easily grown on the colony of Escherichia coli as a nutrient source, it did not control the disease when it was pre-applied in soil. Before the bioassay of a liquid culture filtrate of KYC 1126 was conducted, its antifungal activity was confirmed on the seedlings applying with the mixture of the pathogen's zoospore suspension and KYC 1126 filtrate. On greenhouse experiments with five and four replications, the control value of KYC 1126 on phyllosphere and rhizosphere was 88% and 36%, respectively. Whereas, the control value of dimetnomorph+propineb on phyllosphere was 100% and that of propamorcarb on rhizosphere was 44%. There was a phytotoxicity of the myxobacterial filtrate when seedlings were washed and soaked for 24 hours. Gummy materials were covered with roots. And stem and petiole were constricted, then a whole seedling was eventually blighted.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.3
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• pp.163-171
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• 2017

Effects of different packaging methods for maintaining the shelf life and postharvest quality of iceberg lettuce (Lactuca sativa L.) were studied after harvesting in summer season. Lettuce heads were packaged in plastic crate with or without different films such as (A) Individual lettuce head sealed packaging with linear low density polyethylene (LLDPE) film; (B) Packaging lettuce head in plastic crate and wrapped with LLDPE film; (C): Individual lettuce head sealed packaging with perforated high density polyethylene (HDPE) film; (D) Packaging lettuce head in plastic crate and wrapped with perforated HDPE; and (E) Packaging lettuce head in plastic crate without any film (control), and stored at $2^{\circ}C$ for 35 days. Several quality parameters such as fresh weight loss, SPAD (soil & plant analyzer development) meter value, respiration rate, moisture content and appearance of lettuce were investigated. The lettuce wrapped with individually-sealed LLDPE film showed the lowest weight loss and the highest SPAD value rendering the best appearance index among the treataments throughout the three-week storage period at $2^{\circ}C$. Extending the freshness of iceberg lettuce during low temperature storage will definitely increase the salability potential in the domestic market even during summer season.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.6
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• pp.644-653
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• 2013

In this paper, a formulation for obliquely incident electromagnetic wave has been presented for an analysis of highpower electromagnetic pulse penetration into multilayered dispersive media. Based on generalized models of measured dielectric constants and propagation channels reflecting the Earth's general features, the propagation phenomenon of the obliquely incident early-time(E1) high altitude electromagnetic pulse(HEMP) is analyzed. In addition, the polarization and critical angle are also considered. It is found that the total reflection occurs at an incident angle of about 38 degrees at the soil-rock interface, and that the parallel-polarized E1 HEMP penetrates better than the perpendicular-polarized one. The peak level of the penetrating electric field is found to be 5.6 kV/m at normal incidence, regardless of the type of polarization, and E1 HEMP is greatly reduced near the critical angle. Moreover, the penetrating E1 HEMP is analyzed as a variation of moisture content and depth of materials, resulting E1 HEMP could be useful in determining the levels of shielding required for buried facilities.

• Journal of Radiation Protection and Research
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• v.35 no.3
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• pp.117-123
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• 2010

Plutonium is by far the most important of the transuranic elements which have been released into the environment due to radio-toxicity and long term radiation effects on humans. And Pu isotope ratio ($^{240}Pu/^{239}Pu$) is of great interest because this ratio is used as a fingerprint for different sources. Mass spectrometry has been used as an useful atom counting technique with several advantages over decay counting techniques for the determination of Pu isotopes. It enables a determination of Pu isotope ratio in the environmental samples with a low detection limit and a short determination time. An ICP-MS is the representative mass spectrometry for Pu determination. In this study, the precision of $^{240}Pu/^{239}Pu$ isotope ratio was improved by using 4 multiple ion counters of MC-ICP-MS. The detection limit of $^{239}Pu$ and $^{240}Pu$ were $0.10\;fg\;ml^{-1}$ ($0.24\;{\mu}Bq\;ml^{-1}$), $0.12\;fg\;ml^{-1}$ ($0.97\;{\mu}Bq\;ml^{-1}$), respectively. The relative standard deviation of $^{240}Pu/^{239}Pu$ isotope ratio was less than 1 % in trace level. The various reference materials (seawater, soil and sediment) were analyzed to verify this method and their analytical results were in good agreement with the certified (or recommended value) value.

• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.712-718
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• 2009

To look into the degree of the long distance movement of the air pollution within Mt. Kyebang, Hongcheon, one of the clean regions, major ions, components of collected wet precipitation, were analyzed by using the ion chromatography after measuring pH and electrical conductivity. The quality assurance of chemical composition data was checked by considering the ion balance and electrical conductivity. Also, the pH of precipitation showed in the pH5.0~5.5 range, less than the pH5.6 in which the standards of the acid precipitation. On the whole, the more precipitation got, the less ion concentration became.: It could showed what it influenced on the fluctuation of the precipitation pH according to fluctuation and neutralization of the according materials. In the meantime, as composition ratios of wet deposition, ${SO_4}^{2-}$ and $nss-{SO_4}^{2-}$, ${NH_4}^+$ and $nss-Ca^{2+}$ accounted for high percentage. Especially, as the concentration of ${SO_4}^{2-}$, the artificial pollutant, and $Ca^{2+}$, the soil substance, showed high, Mt. Kyebang, Hongcheon having barely fixed air-pollutants sources was most likely to be influenced by the pollutants moved from long distances.