• The Journal of Engineering Geology
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• v.28 no.1
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• pp.61-67
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• 2018

Grouting is reinforcement or cutoff method which uses the hardening agent which is typically represented by portland cement and injected into the ground or the structure. When mixing the cement in powder form with water, the particles tend to cohere each other. Once they cohered, the particle size tends to become larger while injection efficiency becomes lower. This study, in a bid to reduce the cohesion of cement, the screen was set inside the grout mixer so that the cement particles are separated while vibrating them. To validate the effect of vibration screen, comparison test was conducted by using ordinary portland cement, slag cement and micro cement. Viscosity test, bleeding test and grain-size analysis indicated that the characteristics varied significantly after passing through the vibration filter. It is expected that the vibration filter installed inside the grout mixer will reduce the cement cohesion when mixing with water.

• Journal of the Korean earth science society
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• v.24 no.6
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• pp.568-577
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• 2003

The purpose of this paper is to examine the geomorphic processes of beach and sanddune development in the Chungcheong-Namdo Province. The sands consist mainly of quartz and feldspar with lesser amounts of mica and other heavy minerals. With the exception of those from the granite, the sands have a very fine texture. Another characteristic of the sand grains is low degrees of roundness and grading indicating that source areas for the material were in the vicinity of the accumulating field. Over the years, the beaches have receded as a response to the decreasing amount of depositional materials. The driving force for the formation and transformation of coastal dunes in the study area is dominant winds from the center of the Siberian High. To some extent, the erosion of coastal dunes has been a global phenomenon. The degradation process occurred most actively when spring tides attacked beaches, berms, and foredunes. The relief and shape of present-day coastal dunes is determined initially by the Pleistocene strata underneath. From the fact that the strata contained traces of frozen structure, it can be inferred that sediment once experienced the process of soil formation.

• Journal of Plant Biotechnology
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• v.31 no.3
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• pp.225-230
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• 2004

We employed single cell gel electrophoresis method (comet assay) to analyze the degree of nucleus-DNA damage in the leaves of red pepper (Capsicum annuum L.) seedlings exposed to $^{60}$ CO v-radiation stress. Nucleus-DNA damage was measured as the ratio of tail length (T) to head length (H) in individual comet image isolated from pepper leaf cell. The T/H ratio of control-cells and treated-cells at 50 or 100 Gy were 1.28 and 3.54 or 3.39, respectively, suggesting that nuclei of pepper cells were severely damaged in the integrity of DNA strand by the treatment of enhanced v-radiation. The percentage of head-DNA in control-cells was 76.8%, whereas those of 50 and 100 Gy treated-cells were 55.9% and 59.9%, respectively. Pretreatment of low dose (4 to 20 Gy) radiation to seeds decreased DNA-damage in the leaves of seedlings treated with high dose radiation at 50 or 100 Gy. In this experiment, we developed a sensitive, reliable and rapid method for evaluating genotoxic effect in the nuclei of plant cells by employing comet assay.

• Microbiology and Biotechnology Letters
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• v.18 no.6
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• pp.660-661
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• 1990

A stable preservation method of extracellular non-occluded virion of Autographa californica nuclear polyhedrosis virus (AcNPV) was studied. AcNPVL-1 strain infected to Spodoptera frugiperda cell line and then the culture media were centrifuged. After centrifugation the supernatant containing extracellular nonoccluded virions of the AcNPV was harvested and incubated at $4^{\circ}C$ . Even after the extracellular nonoccluded virions were incubated at $4^{\circ}C$ for about 11 years, the infectivity and multiplication property of the nonoccluded virions in the S. frugiperda cell line were normal. However the titers of the nonoccluded virions in TC-100 medium measured about 11 years ago decreased from $8.9 \times 10^7\; to \;3.8 \times 10^5$ pfu per ml. The AcNPV genome DNA fragment patterns from digestion with Hind11 and EcoRI restriction endonucleases did not change. The AcNPV nonoccluded virions were stable at $4^{\circ}C$ in the cultured medium of more than 10 years and the preservation of AcNPV nonoccluded virions at $4^{\circ}C$ is easy and useful for handling.

• Korean Journal of Ichthyology
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• v.22 no.4
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• pp.273-278
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• 2010

Partial nucleotide sequences of nuclear protein-coding recombination activating gene 1 (RAG1) gene of two Abbottina and five Microphysogobio species residing in Korea were analyzed to elucidate the molecular phylogenetic position of A. springeri Banarescu and Nalbant. In RAG1 tree A. rivularis was clearly separated from the monophyletic lineage composed of A. springeri, Biwia zezera and Microphysogobio species. Within this lineage B. zezera showed sister-group relationship to the monophyletic group composed of A. springeri and five Microphysogobio species. Thus, our phylogenetic tree revealed the polyphyletic nature of two Abbottina species from Korea, which result is well congruent with the previous phyletic assumption based on osteological features. The current classification of Abbottina and Microphysogobio based on morphological criteria, such as the presence or absence of papillae on lips and size of swim bladder with or without encapsulation, does not reflect their true evolutionary history.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.521-524
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• 2008

The purpose of this study is to identify the character and condition of Cr in the clinker and thereby contribute to the research for reduction in utilizing Cr in the cement manufacturing process. The concentration of chromium by cement particle size and the distribution of chromium by clinker mineral were measured. Next, correlation was considered between chromium and the soluble components in cement. As a result, in the range that cement particles were 20${\mu}$m or less, highest soluble hexavalent chromium was found. When the concentration of chromium was measured through mineral separation, belite and the interstitial phase were higher in chromium than in alite. soluble hexavalent chromium was contained in domestic cement less than 20ppm, and its conversion ratio was somewhat high as 10 to 40% or so.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1200-1205
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• 2002

Construction of Private networks is becoming easier due to the openness of telecommunication market, rapidly developing telecommunication technology. The size of existing private networks is becoming huge which resulted in surplus of capacity of the networks. These trends will generate a problem of efficient use of national telecommunication resources and which will be a factor for the structure of domestic telecommunication market which will have a big impact on the existing telecommunication carriers. Therefore, national policy of private network issues should be considered along with the national efforts for the information infrastructure, control of telecommunication market, fairness of competition, strength Power of national competition. In this paper it will be suggested that the efficient policy on the issue of domestic private network, by analyzing present situation, status quo, laws, regulation and procedure for domestic private networks and comparing it with those of U.S.A, Japan, EU.

• Journal of Energy Engineering
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• v.5 no.1
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• pp.8-18
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• 1996

As a part of comprehensive IGCC process simulation, the thermal performance analysis was performed for coal gas firing combined power plant. The combined cycle analyzed consisted of il Texaco gasifier and a low temperature gas cleanup system for the gasification block and a GE 7FA gas turbine, a HRSG and steam turbine for the power block. A steady state simulator called ASPEN(Advanced System for Process Engineering) code was used to simulate IGCC processes. Composed IGCC configuration included air integration between ASU and gas turbine and steam integration between gasifier, gas clean up and steam turbine. The results showed 20% increase in terms of gas turbine power output(MWe) comparing with natural gas case based on same heat input. The results were compared with other study results which Bechtel Canada Inc. performed for Nova Scotia power plant in 1991 and the consistency was identified within two studies. As a result, the analysing method used in this study is verified as a sound tool for commercial IGCC process evaluation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.8
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• pp.790-796
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• 2011

The system which is exposed in the impact range of High-altitude Electromagnetic Pulse(HEMP) may get serious damage because HEMP has a very large electric field value, a very fast rise-time, and so on. Electromagnetic analysis should be performed for signals coupled to the opening or cables of the system prior to derive the system design specifications in order to protect the system against HEMP adequately. In this paper, we analyzed the HEMP coupled signals for the coaxial cable which is generally used to transmit and receive video or RF signals and compared the coupled signal of the one wire with that of the inner conductor of a coaxial cable to confirm the decreased effect of HEMP by the shield. The coaxial cable is analyzed by the external and internal region of the shield separately. For the external region of the coaxial cable, general scattered equation was applied to calculate currents on the surface of the shield and for internal region of the coaxial cable, chain matrix algorithm is used. To verify this paper the analyzed results were compared the results of the existing paper and the two results have good agreements.

• KSBB Journal
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• v.11 no.1
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• pp.37-45
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• 1996

Marine bacterial strain, highly effective agar degrading, was isolated from south sea of Korea and was identified as Pseudomonas sp. This strain was named Halophilic Pseudomonas sp. W7 and accumulated an extracellular agarase which showed a high level of enzyme activity in the presence of agar and agarose. This extracellular agarase was purified by anion-exchange chromatography and gel filtration. Purified agarase showed a single protein band upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis and its molecular weight was estimated to be about 89KDa. The agarase gene was cloned into Escherichia coli JM83 using the plasmid vector pUC19. DNA fragments(3.7, 3.0Kb) of Hind III-digested chromosomal DNA of Pseudomonas sp. W7 was inserted into the Hind III site of pUC19. Selected transformants, E. coli JM83/pSWl 000000and E. coli JM83/pSW3, produced agarase and this agarase was accumulated In the cytoplasmic space.