• Journal of Biosystems Engineering
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• v.14 no.4
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• pp.272-281
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• 1989

It is desirable for the vertical wind tunnel which can build uniform air flow across the vertical duct to be used for the purpose of the investigation of the aerodynamic properties of grains. This study was conducted to examine how the air velocity profile in the vertical duct is influenced by the various alternations of the elements of the wind tunnel, and to prepare design guidance of the vertical wind tunnel which can be used for investigating aerodynamic properties of grains. In addition, several tests were conducted to locate the test section which can be applicable for determining the terminal velocity of grain. The following conclusions were obtained from the study: 1. The size and the location of the outlet of the plenum chamber should be determined such that the outlet air flow is less affected by the air flow and the back pressure by the side wall of the chamber. 2. The honeycomb was not helpful for attaining uniform air flow in case that the air flow profile at the bottom of the vertical duct is serverely different from the ideal one. 3. Even though considerable pressure drop was resulted from the screens installed within the vertical duct, the screens were helpful for attaining uniform air flow in the duct. 4. It is desirable for the test section to be located at the position that not only the air flow of the duct is not disturbed by the distorted back pressure in the plenum chamber, but also less boundary layer is developed.

• Horticultural Science & Technology
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• v.16 no.4
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• pp.511-513
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• 1998

Tomato fruits(Lycopersicon esculentum $M_{ILL}$.) picked at mature (from mature green to breaker) and ripe (from pink to red) stage were packed into two layers in corrugated fiberbox and transported 200km and 400km from the harvested site. Loss (abrasion + cracking) in marketability was lowest (11.0%) from mature + 200km transport, followed by mature + 400km transport(13.5%), ripe + 200km transport(28.5%), and ripe + 400km transport (45.5%). When data were pooled by fruit maturity, firmness of mature fruit was 1.55 times higher than ripe fruit. However, vitamin C content was 1.25 times higher in ripe fruit than in mature fruit. Fruit transported longer distance and packed in bottom layer within a box exhibited lower firmness and vitamin C content in both maturity. It was concluded that it is desirable to transport relatively shorter distance for ripe tomato and longer distance for less ripe fruit.

• Journal of the Korean GEO-environmental Society
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• v.15 no.3
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• pp.49-55
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• 2014

Characteristics of sedimentation of dredged soil is depended on the field condition and characteristics of dredged soil because dredged fill ground was formed by various field condition, sedimentation and self-weight consolidation process of dredged soil. Dredged fill ground is formed as separated sedimentary layer by characteristics of dredged soil. Therefore, it requires some special test method to consider a various field condition, characteristics of sedimentation and self-weight consolidation of dredged soil. In this study, in order to identify the characteristics of sedimentation of dredged soil with disposing velocity geo-centrifuge test and laser particle size analyzer were performed. As a results, river and mixed dredged soil show the separation sedimentation by soil particle size. And sedimentation of clayey dredged soil is parallel to the bottom surface of dredged fill space.

• The Korean Journal of Ceramics
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• v.6 no.3
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• pp.258-261
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• 2000

Highly (h00)-oriented (Ba, Sr)TiO$_3$(BST) thin films were grown by pulsed laser deposition on the perovskite LaNiO$_3$(LNO) metallic oxide layer as a bottom electrode. The LNO films were deposited on SiO$_2$/Si substrates by rf-magnetron sputtering method. The crystalline phases of the BST film were characterized by x-ray $\theta$-2$\theta$, $\omega$-rocking curve and $\psi$-scan diffraction measurements. The surface microsturcture observed by scanning electron microscopy was very dense and smooth. The low-frequency dielectric responses of the BST films grown at various substrate temperatures were measured as a function of frequency in the frequency range from 0.1 Hz to 10 MHz. The BST films have the dielectric constant of 265 at 1 kHz and showed multiple dielectric relaxation at the low frequency region. The origin of these low-frequency dielectric relaxation are attributed to the ionized space charge carriers such as the oxygen vacancies and defects in BST film, the interfacial polarization in the grain boundary region and the electrode polarization. We studied also on the capacitance-voltage characteristics of BST films.

• Conservation Science in Museum
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• v.6
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• pp.47-54
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• 2005

The elements of the pigments used on the wall painting in Ssangyeongchong (Tomb of Two Pillars) from Goguryeo in the Nampo area of Pyeongyang were analyzed to confirm their mineral compositions and features of the painting. Specifically, the non-destructive X-ray fluorescence spectrometer (XRF) was used. On the other hand, the mineral composition of the background and pigment layers were analyzed using an X-ray diffractometer (XRD). The results of these analyses suggested that the lips of the characters in the painting were painted with HgS, and their faces, painted with HgS(Cinnabar/ vermilion) mixed with CaCO₃. Note that lead white pigment [2PbCO₃·Pb(OH)₂] was found only on the bottom layer of the painting, indicating that the wall painting was likely to have been created using the Secco method.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.139-145
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• 2005

In the study, in order to deposit TaN thin film using diffusion barrier and bottom electrode we made the Plasma Assisted ALD equipment and confirmed the electrical characteristic of TaN thin films deposited PAALD method, PAALD equipment depositing TaN thin film using PEMAT(pentakis(ethylmethlyamlno) tantalum) Precursor and $NH_3$ reaction gas is aware that TaN thin film deposited of high density and amorphous phase with XRD measurement The degree of diffusion and react ion taking place in Cu/TaN(deposited using 150 W PAALD)/$SiO_2$/Si systems with increasing annealing temperature was estimated from MOS capacitor property and the $SiO_2(600\;\AA)$/Si system surface analysis by C-V measurement and secondary ion material spectrometer(SIMS) after Cu/TaN/$SiO_2(400\;\AA)$ system etching. TaN thin film deposited PAALD method diffusion barrier have a good diffusion barrier property up to $500^{\circ}C$.

• Fire Science and Engineering
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• v.34 no.4
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• pp.101-106
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• 2020

This study analyzed flame growth characteristics and carbonization patterns when floor materials were burned vertically using a needle flame produced for this study. It was found that PVC flooring was fire retardant and the area under direct flame contracted inward. Vertical combustion causes solidification in the form of a lump at the bottom and also generates soot in a pattern that progresses upwards. This study found that laminated flooring exhibited no fire retarding characteristics and that the laminated layer of its upper surface was destroyed by fire, causing irregular delamination. The carbonization ranges at the left and right sides were determined to be symmetrical. A vertical combustion test of a sample carpet showed that it exhibited no fire-retarding characteristics. It was observed that if heat accumulated in the carpet, the flame formed an ascending air current, and that when flammable materials were present around the flame, they further accelerated the diffusion of the flame. The carbonization pattern at the carpet surface exposed to direct flame revealed that the carpet surface had melted and had flown downwards and that many tiny holes formed on it.

• Ocean and Polar Research
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• v.27 no.4
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• pp.381-395
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• 2005

The spatial distributions of macrobenthic communities in Masan Bay were investigated during summer and winter, 2004. A total of 104 species were sampled with mean density of $448ind./m^2$ and biomass of $77.1g/m^2$ in winter. In summer, a total of 107 species occurred with $485ind./m^2$ and a biomass of $94.5g/m^2$. The most dominant species in winter were Paraprionospio pinnata (24.2%) among polychaetous worms and Theora fragilis (14.1%) among molluscs, but they were replaced in summer by Prionospio chirrifera (20.4%) and Lumbrineris longifolia (14.5%). The difference in species composition and abundance of benthic communities between the two seasons was due to the hypoxia in the bottom layer of the inner bay during summer, which defaunated the macrofauna of the sediments. In the winter when DO concentration increased to normoxia, the pelagic larvae of benthic fauna settled in the soft sediments, but there was a spatial gradient in values of total biomass, density, and H' and benthic pollution index (BPI): higher values were found toward the mouth of the bay. The multivariate analyses like the cluster analysis and MDS ordination showed that Masan Bay could be divided into two or four stational groups in winter and summer whether the hypoxia occurred or not. Group I consisted of sites at the inner bay and central area and Group II, sites at the bay mouth. In summer the inner bay area could be further divided into the shallow impoverished area and the deeper abiotic one.

• The Journal of the Korea Contents Association
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• v.15 no.2
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• pp.499-506
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• 2015

The friction velocity is a quantity with the dimensions of velocity defined by the friction stress and density of a wall surface at near wall of flow condition. Also, the friction velocity is the hydraulic parameter describing shear force at the bottom flow. Moreover, it is a very important factor in designing open channel and essential to determine the mixing coefficient in the main flow direction. The estimation of the friction velocity are such as methods using channel slope, linear law of the mean velocity at viscous sub-layer and direct measurement of wall shear stress, etc. In the present study, we propose a friction velocity equation that has been optimized by combining the concept of entropy, which is used in stochastic method, and to verify the proposed equation, the experimental data measured by Song was used. The R squared for friction velocities between proposed equation and friction velocity formula analyzed 0.999 to 1.000 in a very good agreement with each equation.

• Journal of Korea Water Resources Association
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• v.47 no.9
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• pp.743-752
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• 2014

Delay time for groundwater recharge means the travel time from the bottom of soil layer to groundwater through vadose zone after infiltration from rainfall. As it is difficult to measure delay time, we suggested an empirical formula which is derived by using linear regression between altitude and delay time. For the regression analysis, 4 major gauging watersheds were chosen (Hancheon, Kangjeongcheon, Oedocheon, Cheonmicheon) with 18 measured groundwater level stations. To verify this empirical formula, derived equation from linear reservoir theory was applied to compute delay time and to compare estimated amounts of groundwater recharge using both methods. The result showed good agreement. Furthermore, if derived empirical formula would be linked with SWAT model, the spatial time delay effect in the watershed could be reflected properly.