• Atmosphere
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• v.15 no.1
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• pp.35-46
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• 2005

Today, the outreach of National Meteorological Service such as PC cluster based Numerical Weather Prediction (NWP) technique is vigorous in the world wide. In this regard, WMO (World Meteorological Organization) asked KMA (Korea Meteorological Administration) to formulate a regional project, which cover most of RA II members, using similar technical system with KMA's. In that sense, Meteorological Research Institute (METRI) in KMA developed Mongolian NWP System (MNWPS) based on PC cluster and transferred the technology to Weather Service Center in Mongolia. The hybrid parallel algorithm and channel bonding technique were adopted to cut cost and showed 41% faster performance than single MPI (Message Passing Interface) approach. The cluster technique of Beowulf type was also adopted for convenient management and saving resources. The Linux based free operating system provide very cost effective solution for operating multi-nodes. Additionally, the GNU software provide many tools, utilities and applications for construction and management of a cluster. A flash flood event happened in Mongolia (2 September 2003) was selected for test run, and MNWPS successfully simulated the event with initial and boundary condition from Global Data Assimilation and Prediction System (GDAPS) of KMA. Now, the cluster based NWP System in Mongolia has been operated for local prediction around the region and provided various auxiliary charts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.471-477
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• 2012

SCM420 steel tempered after performing gear hove PACVD carbide coating on the surface after the cutting surface hardness was high. Difficult-to-cut, without coating is classified as mild as large, including materials like mild, high strength that improves tool life and productivity have limited availability. Drive to improve it in the TiCN-coated carbide call for war to the finish coating on cutting a hob skiving good workability, tool wear less, 2.5-fold increase in tool life results were obtained. Experiments using CNC Skiving hobbing machine with wet cutting conditions, cutting speed and feed rate to apply a variety of the tool wear and surface roughness data were obtained. Results from condition 2 (V = 200m/min F = 0.7mm/rev) cutting speed feed mark the cutting surface microstructure and surface roughness Rmax $4.7{\mu}m$(Ra $1.19{\mu}m$) of the data was obtained.

• Journal of Environmental Science International
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• v.17 no.1
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• pp.113-118
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• 2008

[ $6{\sim}13mg/L$ ] base water concentration on monthly BOD has been kept at the Geukrak bridge point for this research target and it indicates the water quality under the existed rank. Due to this present condition of water quality, the demage of ecology from the upper stream to the lower one of the bridge could be conjectured. Moreover, nonstructural extinction of the ecology seems to have gotten worse between both the streams of Yeoungsan River. On this research, eco-corridor between the upper stream and the lower stream of the river should be ensured, the ecological demage needs to be cut off, a dispersed discharge method which the existed method of the 1st sewage plant in Gwangju was enhanced to should be inducted for the procuring of various water ecosystem, and the conditions by the scenario suggested from this research could be applied to a water quality model. then, analysis the improvement effect of the water quality adjacent the river. From the test result, Case3-Type1 scenario is thought to be the best one. From the test result with Case3-Type1 when the concentrated discharge was never done, 0.07 mg/L of BOD concentration was increased at the lower stream where Yeoungbon B point (Haksan Bridge) is but the water improvement effect of $0.24{\sim}2.87mg/L$ is thought to have been done at the area of water deterioration.

• KSBB Journal
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• v.7 no.2
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• pp.85-91
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• 1992

The role of NAA(1-Naphthaleneacetic acid) and BA(6-Benzyladenine) in the adventitious shoot regeneratlon from Populus leaf segments and changes in the pattern of RNA and protein synthesis were investigated. The adventitious shoot regeneration octured at the basal cut end of Populus leaf segments. This process was effected by many factors, including wounding culture conditions, light and plant growth regulators etc. The highest adventitious shoot regeneration frequency was obtained at $0.01mg/\ell$ NAA with $0.2mg/\ell$ BA. In this condition adventitious shoot starved to regenerate on the 13th day of oullure. The most optimal hormone composition for RNA and protein synthesis was $0.01mg/\ell$ NAA with $0.2mg/\ell$ BA. The content of RNA and protein was greater at the proximal part. In the course of adventitious shoot regeneration, the proteins associated with polar-regeneration appeared at the proximal part of populus leaf segment.

• Journal of the Korean Geosynthetics Society
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• v.5 no.3
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• pp.9-15
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• 2006

The Green Wall system is one of segmental concrete crib type earth retaining wall. Green wall is constructed as procedures that lay the front stretchers, rear stretchers and headers then making a rigid body through harden filled soil of interior cell. Recently, Green Wall method is applied in variable cutting ground construction because of advantage which minimize to cut base ground. In case of Green Wall method is constructed with soil nail method, expect that total system stability will increase more than flexible facing because of facing stiffness is big. However, in this case of design, facing stiffness is not considered so that is poor economy. Hence, in this study, stability increasing effect of total system analyze about that soil nail method is constructed with rigidity facing like a Green Wall method. In present study, laboratory model tests was performed for analysis on stability increasing effect of total system about changing stiffness of facing. LEM analysis conducted for evaluation on safety factor of total system sliding that facing condition changed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.2
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• pp.135-140
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• 2009

This paper discusses how to change the electromagnetic waves' property in the cut-off causing discontinuity existing in the guiding structure of the RF passive component by using the metamaterial and elaborates on its principle. Particularly, we find and explain, from the viewpoint of electromagnetics and circuit theories, the so-called tunneling condition that when the segment with an extremely narrow cross-section leading to blockage in the parallel-plate waveguide is given the ENZ(Epsilon Near Zero) for its filling material, the wave starts to propagate through the segment. The analysis method as a transmission-line theory taking the discontinuity and material change into consideration is shown valid through the comparison with other methods for analyzing parallel-plate waveguides, and provides the illustration of the S-parameters and impedance describing the characteristics of the tunneling.

• Fire Science and Engineering
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• v.18 no.4
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• pp.16-21
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• 2004

This paper has investigated influences of pollutants in air-breathing on the respirators and it by year of disused air respirators that fire fighter is using in domestic cutting done air respirators after collection observed state of cylinder material through instrumental analysis, and cut open pipe to confirm pollution degree of pipe from cylinder of air respirators to airline mask and confirm pollution availability. The metal surface inside the air respirators was corroded by moisture included in the compressed air. The material generated by corrosion is white powder of less then 100㎛, which is analyzed as aluminum hydroxide corroded by moisture. This aluminum hydroxide powder may get into the lung while one breathes in, and it is easy to be attached to the lung so it will cause a serious influences to human health. This study suggests that Korea should set out the standards for components and composition of breathing air as soon as possible.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.61-65
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• 2005

This paper describes the cut off time and the current characteristics of virgin RCDs and deteriorated ones in the seashore. The RCDs(Residual Current Protective Devices) are used for protecting the human body from electrical shock and for preventing facility accidents. According to the Korean standards, the RCDs are installed in panel boards. When RCDs are installed outside, they must be enclosed inside waterproof cases. In the case that RCDs are employed at temporary power sites and electrical facilities on the road they are exposed to the external environment. As a result, the RCDs deteriorated in the seashore for 3 months showed high failure rate, while the virgin RCDs all complied with Korean Standard. Considering that the RCDs are used under exposed condition outside, the reliance of RCDs must be ensured by modifying the related regulations and codes and by developing improved advanced in their performance.

• Journal of the Korean association of regional geographers
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• v.1 no.1
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• pp.61-68
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• 1995

The writers study on the development and the prospect of computer map based on the most recent computer mapping technical aspects. We also study domestic prospect of computer map in connection with the present condition of domestic GIS. The main results are as follows: (1) Computer map has rapidly developed in spite of its short history. We expect that computer map will be improved more in the future owing to the development of computer hardware and software. Most mapping processes will be possible sooner or later owing to Artificial Intelligence(AI) and more improved scanner without human effort. (2) Computer map can be used for various industrial fields and its development can give a great help for technical advance in correlated industries. (3) Computer map has really developed in the country since 1980, when GIS was introduced. Especially, government planned to digitalize all the basic topographical maps covering the whole country between 1996-1998. We think that there is an epoch-making change in the development history of computer map in the future. (4) The development of GIS is closely connected with one of computer map, but the recent technical levels of GIS is not perfect. So there is an urgent need for technical supplement to produce good computer maps. (5) The government had better construct GIS database in order to cut down expenses derived from overlapping input of data by individual users and there is a need for data standard.

• Restorative Dentistry and Endodontics
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• v.14 no.1
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• pp.71-84
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• 1989

The purpose of this study was to evaluate the effect of tricalcium phosphate and Vitapex on the dogs' periapical tissues. Twenty mandibular premolars from 5 healthy dogs were used for this study. After the animals were anesthetized intramuscularly, pulp chambers were open and pulp tissue was extirpated with a barbed broach and H-file. Then the working length of the root canal was measured with H-file and pulp tissue was completely removed. Before the actual canal filling, the root canals of twenty teeth have been experimentally infected with opening the pulp chamber for 5 weeks. Periapical radiographs of the experimental teeth were taken to monitor the periapical pathological condition. Each root apex of 20 premolars was perforated with engine reamer and the root canals were enlarged with No. 30-60 H-files. They were divided into treated as follows. Control group: The root canal was filled with gutta-percha. Experimental group 1: The canal was dried with sterile paper points and mixture of tricalcium phosphate and physiological saline was overfilled beyond the root apex with a lentulo spiral. Then the root canal was filled gutta-percha and lateral condensation and the pulp chamber was filled with Caviton. Experimental group 2: The root canals were overfilled with Vitapex and were treated in the same manner as those in experimental group 1 At 1,2,3, and 8 weeks after experiment, the periapical tissues including the alveolar bone were fixed with 10% formalin solution for I week and decalcified with Plank-Rycho solution for 5 weeks. The specimens were embedded in paraffin and serial sections were cut into a thickness of 6 ${\mu}m$ at the plane of the root apex. Hematoxyline-eosin and Masson's trichrome stain were made for the histo-pathological examinations. The results were as follows: 1. Ingrowth of collagen fiber was observed from 1 week in control group and experimental groups. 2. The rate of bone formation of experimental group 1 was accelerated more than that of experimental group 2. 3. Resorption of cementum was seen in control group, but apposition of cementum was seen in experimental groups.