• Journal of the Korean Institute of Gas
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• v.24 no.2
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• pp.1-8
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• 2020

Centrifugal pump is a facility that transfers energy to fluid through centrifugal force, which is usually generated by rotating the impeller at high speed, and is a major process facility used in many LNG production bases such as vaporization seawater pump, industrial water and fire extinguishing pump using seawater. to be. Currently, pumps in LNG plant sites are subject to operating conditions that vary depending on the amount of supply desired by the customer for a long period of time. Pumps in particular occupy a large part of the consumption strategy at the plant site, and if the optimum operation condition is not available, it can incur enormous energy loss in long term plant operation. In order to solve this problem, it is necessary to identify the performance deterioration factor through the flow analysis and the result analysis according to the fluctuations of the pump's operating conditions and to determine the optimal operation efficiency. In order to evaluate operation efficiency through experimental techniques, considerable time and cost are incurred, such as on-site operating conditions and manufacturing of experimental equipment. If the performance of the pump is not suitable for the site, and the performance of the pump needs to be reduced, a method of changing the rotation speed or using a special liquid containing high viscosity or solids is used. Especially, in order to prevent disruptions in the operation of LNG production bases, a technology is required to satisfy the required performance conditions by processing the existing impeller of the pump within a short time. Therefore, in this study, the rotation difference of the pump was applied to the ANSYS CFX program by applying the modified 3D modeling shape. In addition, the results obtained from the flow analysis and the curve fitting toolbox of the MATLAB program were analyzed numerically to verify the outer diameter correction theory.

• Progress in Medical Physics
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• v.25 no.4
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• pp.233-241
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• 2014

The aim of this study is to develop a new software tool for 3D dose verification using $PRESAGE^{REU}$ Gel dosimeter. The tool included following functions: importing 3D doses from treatment planning systems (TPS), importing 3D optical density (OD), converting ODs to doses, 3D registration between two volumetric data by translational and rotational transformations, and evaluation with 3D gamma index. To acquire correlation between ODs and doses, CT images of a $PRESAGE^{REU}$ Gel with cylindrical shape was acquired, and a volumetric modulated arc therapy (VMAT) plan was designed to give radiation doses from 1 Gy to 6 Gy to six disk-shaped virtual targets along z-axis. After the VMAT plan was delivered to the targets, 3D OD data were reconstructed from 512 projection data from $Vista^{TM}$ optical CT scanner (Modus Medical Devices Inc, Canada) per every 2 hours after irradiation. A curve for converting ODs to doses was derived by comparing TPS dose profile to OD profile along z-axis, and the 3D OD data were converted to the absorbed doses using the curve. Supra-linearity was observed between doses and ODs, and the ODs were decayed about 60% per 24 hours depending on their magnitudes. Measured doses from the $PRESAGE^{REU}$ Gel were well agreed with the TPS doses at central region, but large under-doses were observed at peripheral region at the cylindrical geometry. Gamma passing rate for 3D doses was 70.36% under the gamma criteria of 3% of dose difference and 3 mm of distance to agreement. The low passing rate was resulted from the mismatching of the refractive index between the PRESAGE gel and oil bath in the optical CT scanner. In conclusion, the developed software was useful for 3D dose verification from PRESAGE gel dosimetry, but further improvement of the Gel dosimetry system were required.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.1
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• pp.77-84
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• 2017

Purpose: To evaluate the image quality improvement and dosimetric effects on virtual monochromatic images of a Dual Source-Dual Energy CT(DS-DECT) for radiotherapy planning. Materials and Methods: Dual energy(80/Sn 140 kVp) and single energy(120 kVp) scans were obtained with dual source CT scanner. Virtual monochromatic images were reconstructed at 40-140 keV for the catphan phantom study. The solid water-equivalent phantom for dosimetry performs an analytical calculation, which is implemented in TPS, of a 10 MV, $10{\times}10cm^2$ photon beam incident into the solid phantom with the existence of stainless steel. The dose profiles along the central axis at depths were discussed. The dosimetric consequences in computed treatment plans were evaluated based on polychromatic images at 120 kVp. Results: The magnitude of differences was large at lower monochromatic energy levels. The measurements at over 70 keV shows stable HU for polystyrene, acrylic. For CT to ED conversion curve, the shape of the curve at 120 kVp was close to that at 80 keV. 105 keV virtual monochromatic images were more successful than other energies at reducing streak artifacts, which some residual artifacts remained in the corrected image. The dose-calculation variations in radiotherapy treatment planning do not exceed ${\pm}0.7%$. Conclusion: Radiation doses with dual energy CT imaging can be lower than those with single energy CT imaging. The virtual monochromatic images were useful for the revision of CT number, which can be improved for target coverage and electron densities distribution.

• Journal of the Korean GEO-environmental Society
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• v.15 no.2
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• pp.67-74
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• 2014

Recently, the number of road construction is increasing by industrial development. According to this industrial tendency, the number of traffic accidents are consistently increasing due to increasing number of vehicle on the road. This is mainly because traffic accidents are occurred by various parameter such as negligence of driver, vehicle defects, state of unstable road, natural environment etc. Lane department of vehicles from guardrail is occurring frequently. This type of accident is caused by vehicle performance improvement and shape of vehicle, weak guardrail installation and maintenance. Guardrail has the purpose on prevention such as prevention of traffic accident and prevention of deviating out of road, minimizing damage of driver and vehicle by collision as well as entry into the road through guardrail. Stability evaluation test of guardrail verifies the behavior of guardrail through the crash of truck. At this time, the crash condition has 100 km/h of velocity and $15^{\circ}$ of impact angle. In the case of ground condition, filling slope condition has relatively high bearing capacity of infinite ground towards the test. Guardrail is generally installed on road of shoulder in fill slope in korea. It is possible for stability problem to deteriorate ground bearing capacity in Guardrail in fill slope. The existed study towards stability of guardrail has been carried out in the infinite ground. However, the study on the behavior of fill slope with guardrail is not performed by vehicle collision. Therefore, In this study, the numerical analysis using LS-DYNA was executed for verification on behavior of fill slope with guardrail through vehicle collision. This numerical analysis was carried out with change of embedded depth on installed guardrail post in shoulder of fill slope by vehicle collision and 8 tonf truck crash providing at NCAN (National Crash Analysis Center). As the result, displacement and stress on fill slope are decreased in accordance with the increase of embedded depth of guardrail post. Ground bearing capacity is deteriorated at depth of 450 mm form shoulder of road on fill slope.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.899-915
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• 2018

In this study, in order to construct an eco-friendly advanced road transportation network, the multi-layer tunnel, which is a small-sized car road, is designed to have a height of less than 60 cm. However, the shape of the tunnel is low and the height of the traffic sign is small. In order to solve these problems, traffic sign characters were designed in three dimensions, and the possibility of applying the design of the three - dimensional sign that can obtain greater visibility than the existing signs at the same distance and the possibility verification through virtual simulation were performed. The three-dimensional sign is horizontally installed on the ceiling of the multi-layer tunnel. To be seen vertically, it is enlarged by a certain ratio by the perspective, and the width and height are enlarged. Respectively. In addition, 3D simulation was performed to verify the visibility of the stereoscopic signs when the driver ran through the stereoscopic sign design specifications. As a result of the design and experimental study, it was confirmed that the stereoscopic sign could be designed through the theoretical formula and that it could provide the driver with a larger traffic sign character because there is no limitation of the facility limit compared to the existing vertical traffic sign. Also, we confirmed that it can be implemented in the side wall by using the stereoscopic sign design principle installed on the ceiling part. It was confirmed that the design of the stereoscopic sign can be designed to be smaller as the distance that the driver visually recognizes the sperm is shorter, the height of the protrusion vertically at the lower part of the stereoscopic sign becomes higher. As a result of 3D simulation running experiment based on the design information of the stereoscopic sign, it was confirmed that the stereoscopic sign is visually the same as the vertical sign at the planned distance. Although the detailed research and institutional improvement of stereoscopic signs have not been made in Korea and abroad, it is evolved into a core technology of new road traffic facilities through various studies through the possibility of designing and applying stereoscopic signs developed through this study Expect.

• Korean Journal of Heritage: History & Science
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• v.40
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• pp.243-270
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• 2007

Linked pearls pattern expressed on textiles have no limited scale or shape when manufacturing, so they are free in expression. And from the design, material, and color we can analogize the social culture of that age. Oriental linked pearls pattern was started from the Sasanian Persia and introduced through the Silk Road, so it is closely connected with the East and the West culture. This study will consider from the 5th century to the 10th century; the mural costume of the West Central Asia, the ancient textiles excavated from the Sinjiang and Qinghai area of China, and the linked pearls pattern which are collected at Shosoin, Japan. And from this study, will concentrate on clarifying the linked pearls pattern's condition of the cultural exchange between the East and the West and it's structural variation process. The design of linked pearls pattern delivered to the East through the Silk Road is differed by area. For example, in the Western Pamir Plateau, where the ancient Sogdians mainly lived, the excavated linked pearls pattern's subject were deer or cassowary variated from the West Asian motif. But the ones excavated from Kucha Xingang had Chinese motifs added so they showed Chinese characters or Buddhist Bodhisattva image instead of Helios. Like this, the appearance of new patterns, which were accompanied by structural variations, gradually deviated from the standardized pattern of the Sasanian Persia. And this structural variation process has relations with the construction and arrangement method of various patterns of the after ages. The foliated floral Spray, which is placed at the lozenge space of linked pearls' space, had developed into ogival - shaped pattern (Neunghwamun). And the prevalence of geometrical structure pattern after the 10th century and the unfolding method of Tapjamun which is arranging unit pattern in order, are similar to the linked pearl pattern. In brief, linked pearls pattern accompanied by technical improvement let us understand the polished artistic code from its expression, and has importance in showing universal pattern beyond region and culture.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.200-211
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• 1993

Somatic hybrids of Pleurotus florida ASI 2016 and Pleurotus ostreatus ASI 2018 were obtained by protoplast fusion. The 40 fusants($P1{\sim}P40$) was examined for the yield on fermented and pasteurized rice straw in a tray. The carpophore yield of them were showed as the range of $27.0{\sim}155.2$, based on parental values of 100(ASI 2018), The pilei of fusants between orange white colored P. florida and dark grey colored P. ostreatus had mixed colors in the young stage. Other breeding programmes were performed to improve new varieties with high yield and good quality. A new oyster mushroom variety, Wonhyeongneutaribeosus(P72), was developed at the Agricultural Sciences Institute, Rural Development Administration in 1990. This P.florida-ostreatus-ostreatus hybrid P72 was selected from 38 protoplast fusion products($P41{\sim}P78$) between P.florida-ostreatus recombinant P5-M 43-arg rib and P. ostreatus ASI 2-13-0 2001-19-pro orn. The yield indexes of 38 hybrids ranged $40.5{\sim}152.7$ compared with the parental values of 100(ASI 2001). Hybrid P72 was characterized by the large fruiting bundle of semispherical shape with long stipe and by the small and circular pileus, resulting in lower harvesting cost. A significant increase in carpophore production was observed in somatic hybrids of protoplasts due to heterosis. A comparision of hybrid with parents P72 was made using isozyme analysis. The esterase banding patterns could be characterized by new bands in the hybrids. Seven fusion products of four crosses between P.florida ASI 2016 and P. ostreatus ASI 2018 were analysed with respect to the distribution of progenies and segregation of gene markers by random basidiospore analysis. Segregation of alleles should yield progeny of four genotypes in a Mendelian ratio of 1 : 1 : 1 : 1 for prototrophs, auxotrophs of one parental type, auxotrophs of the other parental type, and auxotrophic recombinants, respectively. However, five fusants of them did not detect one parental, P.ostreatus, type. Basidiospores could yield progeny of 16 genotypes in the cross of one of the recombinant P5-M43-arg $rib{\times}P. ostreatus$ ASI 2-13-pro orn but the segregants of three fusants were not detected clearly. The allele ratio of loci could be expected 1 : 1 : 1 : 1 for arg, rib, pro and orn. The ratio, however, would be changed to 4 : 1 : 1 : 1 with increasing proportion of argo In almost all the fusants, prototrophic recombinants were recovered in large numbers against auxotrophic markers. Parental genotypes were recovered with the recombinant progeny amounting to $38.68{\sim}99.56%$. The analysis provides proof of heterokaryosis and strong evidence for haploidy of vegetative nuclei, a sexual cycle consisting of nuclear fusion and meiosis.