• Journal of the Korean Society for Railway
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• v.12 no.4
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• pp.457-464
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• 2009

The now velocity distribution at inlet of diesel Particulate filter (DPF) which is connected to each curved duct was simulated using $STAR-CD^{(R)}$. Three kinds of models which describe the shapes of the curved duct ware used for the CFD simulation. The simulation results were compared with the experimental data of velocity distribution which was obtained using a Pitot tube and 2-D positioning machine. At the $90^{\circ}$ curved connecting condition, the CFD simulation results of flow velocity distribution at inlet of the DPF showed a horse hoop shape shifted from the axial center line of the DPF. The CFD simulation results agree reasonably with those of the experiments.

• Analytical Science and Technology
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• v.7 no.4
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• pp.435-440
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• 1994

Qualitative and quantitative analysis for the anionic surfactants used in the metal washing fluid (brand names are BFA and BCA) was performed by the capillary electrophoresis. Acetonitrile and sodium benzoate were mixed with the buffer solution which controlled at pH 10. Under the 18kV applied voltage, the electropherograms have shown the theoretical plates more than $10^4$. Determined as the concentration at the S/N~3, the typical detection limit was ~5 ppm and the calibration curves have shown the correlation coefficients higher than ~0.99. Based on these results, it was concluded that each components were octanoate, decanoate, dodecanoate, tetradecanoate, hexadecanoate and the relative ratio was 1.0 : 1.0 : 6.5 : 2.1 : 0.8 for the BFA.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.6
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• pp.555-561
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• 2000

The remote field eddy current (RFEC) inspection was performed on the ductile cast iron pipes with nominal outer diameter of 100mm, which were machined with various shapes and sizes of defects. Ductile cast iron pipes which are used as water supply pipe have the non-uniform thickness and asymmetric cross section due to relatively high degree of allowable errors during the manufacturing processes. These characteristics of ductile cast in pipes cause the long range background noises in RFEC signals along the pipe. In this study, tile machined defects in pipes were effectively classified by the moving window average (MWA) method which eliminated the long-range noise. The voltage plane polar plots (VPPP) method was used to quantitatively evaluate the depth and circumferential degree of defects. The VPPP signatures showed that the angle between defect signature and the normalized in-phase component on the VPPP is linear to the depth of defects. The nondestructive RFEC technique proved to be capable of quantitatively evaluating the machined defects of underground water supply pipe.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.3
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• pp.116-121
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• 2021

A lot of research is being done to develop a high-efficiency heat pump to save energy, and research to reduce or eliminate the phenomenon of frost occurring in the outdoor unit coil is also being conducted at the same time. A curved constant temperature chamber was constructed that can be tested under the same conditions as in the natural state so that the research can be conducted in which frost does not occur on the outdoor unit of the heat pump regardless of the season. Simulations were performed to verity whether such a curved constant temperature chamber has feasibility as an experimental device. For CFD conditions, the length of the straight duct in front of the outdoor unit located in the duct-type constant temperature chamber was 1, 5, 10 and 15 times the diameter of the duct. As a result, it was found that a straight space must be secured 10 times the diameter of the duct.

• Journal of Ginseng Research
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• v.12 no.2
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• pp.158-163
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• 1988

P. ginseng seedlings treated with GA,2,4-D and B-9 (N,N-dimethylsuccinamic acid) were grown under dark. Growth efficiencies ($E_1$ = St/Ro, $E_2$ = St1(Ro-Rt), $E_3$ = (Ro- Rt)/ Ro where St. Ro and Rt are shoot weight, initial root weight and root weight at time 1. respectiv$E_1$y) and other r$E_1$ated factors and their interr$E_1$ationship were investigated. $E_1$ and $E_3$ showed quadratic r$E_1$ation with temperature change while $E_2$ showed negative linear r$E_1$ation. $E_1$ depended on more $E_3$ component than $E_2$ component. The values of $E_2$ and $E_3$ are almost same. $E_2$ was greater than that reported previously suggesting large variation between roots. GA greatly increased $E_2$ and $E_3$ in supraoptimum temperature range while B-9 greatly decreased $E_3$ in all temperature range and $E_2$ in suboptimum range. Shoot weight showed highly significant positive linear corr$E_1$ation with substrate amount in most cases of PGR and temperature and with respiration loss in some cases. Respiration loss showed significant linear corr$E_1$ation positiv$E_1$y with $E_1$ and $E_3$ and negativ$E_1$y with $E_2$ only in suboptimal temperature range.

• Journal of the Korean Wood Science and Technology
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• v.11 no.3
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• pp.49-57
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• 1983

This study dealts with the penetration of methyl methacrylate(MMA) monomer-solvent system into five Korean major tree species, especially the Pinus koraiensis S. et Z., Pinus densiflora S. et Z., Larix leptoiepis Gordon, Quercus serrata Thunb. and Betula platyphylla var japonica Hara. In this report I described the results of the interaction between wood and polymer loading by catalyst-heat polymerization. On the other hand the influence of penetration of polymer loading on dimensional stabilization on WPC of Pinus koraiensis by catalyst-heat polymerization was also investigated.

• Analytical Science and Technology
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• v.7 no.2
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• pp.155-164
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• 1994

A conventional Grimm-type glow discharge source was constructed and applied to radio-frequency(13.56MHz) discharge for metal and ceramic analysis. We investigated the emission spectrum for aluminium and aluminium oxide and the influence of discharge operating paramaters including argon pressure, rf-power and DC-bias voltages at the sample-side electrode. Scanning Electron Microscope(SEM) also was used to investigate the effect of rf-sputtering on the microstructure formation of the aluminium oxide. Linear analytical calibration curves were constructed for Manganese and zinc element in samples of low alloy steel(BAS 401-405) and brass(NIST 1108-1117).

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.183-187
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• 2020

The molybdenum cup and molybdenum pin, which are the main materials of the molybdenum electrode used for the LCD BLU CCFL electrode, have not been developed in Japan and all of them are imported and used from Japan, is giving a competitive burden. In this research, to develop the manufacturing technology of molybdenum pin used for CCFL electrode of LCD BLU, development of linear processing technology, development of molybdenum wire surface treatment technology, development of wire cutting technology, production of molybdenum pin, design and fabrication of JIG and Fixture for inspection, molybdenum pin prototyping and analysis, and development of 100% molybdenum pin inspection technology. In this paper, especially, In this paper, especially, research on the convergency design for total inspection machine is treated. is treated.

• Journal of Navigation and Port Research
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• v.33 no.10
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• pp.665-669
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• 2009

When maneuvering a ship in a narrow channel or under bridge, the ship operator may take actions of slowdown engine and altering course in order to avoid possible navigational dangers, which may reduce difficulties on navigation or collsion avoidance against other ship and/or bridge. In this paper, taking notice of the stress caused by these actions of slowdown engine and altering course, survey is carried out for whether it is possible to quantify the stress by time delay as an index. Based on the ship handling simulator experiment, it is verified that difficulty of navigation changes is highly correlated with the time delay, which result from compensation actions of slowdown engine and altering course.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.520-526
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• 1991

Retention behavior of lanthanides was studied on the dynamic system using dinonylnaphthalene sulfonic acid cation exchanger and tartaric acid as a complexing agent. The relations between logk' and log$[NH^{4+}]$/log[tartarate], and between logk' and logR showed good linearity in isocratic and gradient elution, respectively. In gradient elution of tartaric acid the slopes were increased as the initial concentrations were decreased. Column efficiencies and resolution of lanthanides on dinonylnaphthalene sulfonic acid equilibrated cation exchanger were found to be better in ${\alpha}$-hydroxyisobutyric acid eluent than in tartaric acid.