• Journal of the Korean institute of surface engineering
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• v.26 no.1
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• pp.3-9
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• 1993

Chemical vapor deposited tungsten films were formed in a cold wall reactor at pressures higher (10~120torr) than those conventionally employed (<1torr). SiH4, in addition to H2, was used as the reduction gas. The effects of pressure and reaction temperature on the deposition rate and morphology of the films were ex-amined under the above conditions. No encroachment or silicon consumption was observed in the tungsten de-posited specimens. A high deposition rate of tungsten and a good step coverage of the deposited films were ob-tained at 40~80 torr and at a temperature range of $360~380^{\circ}C$. The surface roughness and the resistivity of the deposited film increased with pressure. The deposition rate of tungsten increased with the total pressure in the reaction chamber when the pressure was below 40 torr, whereas it decreased when the total pressure ex-ceedeed 40 torr. The deposition rate also showed a maximum value at $360^{\circ}C$ regardless of the gas pressure in the chamber. The results suggest that the deposition mechanism varies with pressure and temperature, the surface reac-tion determines the overall reaction rate and (2) at higher pressures(>40 torr) or temperatures(>36$0^{\circ}C$), the rate is controlled by the dtransportation rate of reactive gas molecules. It was shown from XRD analysis that WSi2 and metastable $\beta$-W were also formed in addition to W by reactions between WF6 and SiH4.

• Asian Journal of Turfgrass Science
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• v.15 no.2
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• pp.39-50
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• 2001

This research was designed to develop the rapid propagation technology of zoysiagrass using carpet production and to provide turf-growing farmers with efficient cultivation methods thor carpet production. Turfgrass cultivar tested in cadet production by seeding was Z. japonica cv. Zenith. Since the surface coverage rate reached to 85% in 2 months after seeding at the rate 6g/$m^2$ in the early part of July, carpet production using ‘Zenith’seeds would be possible to produce within within the same year. Thrfgrasses tested in carpet production by vegetative propagation were Z. japonica, medium type Z. matrella, fine type Z. matrella, and medium type Z. japonica. Planting rates of vegetative parts (sprigs) were 1.2L/$m^2$, 2.4L/$m^2$, 2.5L/$m^2$, and 5L/$m^2$. Two different sizes of sprig were used; 1~2 nodes and 3~4 nodes. Surface coverage rate was 90% in one year after planting at the rate of 2.5L sprigs of medium type Z. japonica. Therefore, the use of sprigs with 3~4 nodes at the planting rate of 2.5L would be suitable for the carpet prodcution. Three months old zoysiagrass carpet (Zenith) was overseeded with Kentucky bluegrass, perennial ryegrass, and tall fescue at two different overseeding rate. Surface coverage rate was the highest (80%) at the plot overseeded with perennial ryegrass that showed the earliest germination. Suitable overseeding species for the rapid sod formation at the early stage of establishment were tall fescue and perennial ryegrass and desirable overseeding time was from early to middle of September.

• Asian Journal of Turfgrass Science
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• v.9 no.3
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• pp.173-185
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• 1995

Hydroseeding technique is a very popular method of revegetating slope areas through the control of soil erosion and stability by seeding grasses. This study was conducted to select turfgrass species and cultivars for hydroseeding. Experiment plots were established on various soil types and environmental conditions at Singar-Ansan high-way construction site. The investigation was designed in three cutting, one back-filling and other three spare sites with various seed mixtures. Results indicated that combinations of seed mixtures influenced seed germination and rates of surface cover. In a view of long term, vegetation shifts should be influenced by characters of slopes and micro-climate conditions. Hydroseeding did not show good results on rocky slope areas. Revegetation was only going on where there had soil. The combination of seed mixture with a higher rate of perennial ryegrass had relatively good revegetation with faster germination and seedling growth. Improved turf-type tall fescue Arid ⓡ and Falcon ⓡ seemed to have good environ-mental adaptation and drought tolerance. Wild or old type cultivars showed relatively slow green-up in spring and growth rates at the next year of seeding. For the harmonious landscaping with surrounding area, the combination of native grass mixture with cool-season grasses had good results. Slow and low revegetation rate at hack-filling site seemed to be caused by the poor development of capillary tubes in sub-soil. It was shown that a high correlation between seed germination and revegetation rate, and between three-month later coverage rate and final rate. The evaluation of coverage rate after three month seems to he acceptable to decide the accomplishment of hydroseeding results on rode side slopes.

• Weed & Turfgrass Science
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• v.3 no.3
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• pp.240-245
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• 2014

This study was carried out to determine the possible use of volcano eruption sand at Merapi mountain area compared with clayey soil, alfisol as turfgrass growing media. Indonesia has abundant source of eruption sand and clayey soil. Native zoysiagrass (Z. matrella) was collected from Sleman district and seashore paspalum (P. vaginatum) from Solo region. The experimental plots were treated with both organic and inorganic fertilizers. Zoysiagrass and seashore paspalum can grow on the mixture of eruption volcano sand and alfisol soil. Fertilizers application increased turf color, surface coverage rate and recovery rate of turfgrass. While fertilizer treated alfisol have no effect on the length and dry weight of zoysiagrass root. Mixing of volcano eruption sand on growing media resulted in longer root length, higher shoot dry weight of zoysiagrass than in alfisol soil. Type of fertilizer affected the pH, soil organic matter, total N, available P, available K and electrical conductivity of sand and alfisol after cultivation. Similarly to zoysiagrass, the recovery of seashore paspalum was increased by application of fertilizer, even the inorganic fertilizer showed faster recovery than organic fertilizer. Surface coverage of seashore paspalum was faster than that of zoysiagrass with or without fertilizer.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.125-132
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• 2006

Transient kinetics of $NH_3$ adsorption/desorption and of SCR(selective catalytic reduction) of NO with $NH_3$ were studied over vanadium based catalysts, such as $V_2O_5/TiO_2$ and $V_2O_5-WO_3/TiO_2$. In the present catalytic reaction process, NO adsorption is neglected while $NH_3$ is strongly chemisorbed on the catalytic surface. Accordingly, it is ruled out the possibility of a reaction between strongly adsorbed $NH_3$ and NO species in line with the hypothesis of an Eley-Rideal mechanism. The present kinetic model assumes; (1) non-activated $NH_3$ adsorption, (2) Temkin-type $NH_3$ coverage dependence of the desorption energy, (3) non-linear dependence of the SCR reaction rate on the $NH_3$ surface coverage. Thus, the surface heterogeneity for adsorption/desorption of $NH_3$ is taken into account in this model. The present study extends the pure chemical kinetic model based on a powdered-phase catalytic system to the chemico-physical one applicable to a realistic monolith reactor.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.3940-3955
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• 2023

A new method of numerical simulating prediction and decontamination effect evaluation for abrasive jet decontamination to radioactively contaminated metal is proposed. Based on the Computational Fluid Dynamics and Discrete Element Model (CFD-DEM) coupled simulation model, the motion patterns and distribution of abrasives can be predicted, and the decontamination effect can be evaluated by image processing and recognition technology. The impact of three key parameters (impact distance, inlet pressure, abrasive mass flow rate) on the decontamination effect is revealed. Moreover, here are experiments of reliability verification to decontamination effect and numerical simulation methods that has been conducted. The results show that: ⁶⁰Co and other homogeneous solid solution radioactive pollutants can be removed by abrasive jet, and the average removal rate of Co exceeds 80%. It is reliable for the proposed numerical simulation and evaluation method because of the well goodness of fit between predicted value and actual values: The predicted values and actual values of the abrasive distribution diameter are Ф57 and Ф55; the total coverage rate is 26.42% and 23.50%; the average impact velocity is 81.73 m/s and 78.00 m/s. Further analysis shows that the impact distance has a significant impact on the distribution of abrasive particles on the target surface, the coverage rate of the core area increases at first, and then decreases with the increase of the impact distance of the nozzle, which reach a maximum of 14.44% at 300 mm. It is recommended to set the impact distance around 300 mm, because at this time the core area coverage of the abrasive is the largest and the impact velocity is stable at the highest speed of 81.94 m/s. The impact of the nozzle inlet pressure on the decontamination effect mainly affects the impact kinetic energy of the abrasive and has little impact on the distribution. The greater the inlet pressure, the greater the impact kinetic energy, and the stronger the decontamination ability of the abrasive. But in return, the energy consumption is higher, too. For the decontamination of radioactively contaminated metals, it is recommended to set the inlet pressure of the nozzle at around 0.6 MPa. Because most of the Co elements can be removed under this pressure. Increasing the mass and flow of abrasives appropriately can enhance the decontamination effectiveness. The total mass of abrasives per unit decontamination area is suggested to be 50 g because the core area coverage rate of the abrasive is relatively large under this condition; and the nozzle wear extent is acceptable.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.281-286
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• 2006

In this study, acquired time series Landsat TM/ETM+ image to extract land surface temperature for wide-area region and executed geometric correction and radiometric correction. And extracted land surface temperature using NASA Model, and I achieved the first correction by perform land coverage category for study region and applies characteristic emission rate. Land surface temperature that acquire by the first correction analyzed correlation with Meteorological Administration's temperature data by regression analysis, and established correction formula. And I wished to improve accuracy of land surface temperature extraction using satellite image by second correcting deviations between two datas using establishing correction formula. As a result, land surface temperature that acquire by 1,2th correction could correct in mean deviation of about ${\pm}3.0^{\circ}C$ with Meteorological Administration data. Also, could acquire land surface temperature about study region by relative high accuracy by applying to other Landsat image for re-verification of study result.

• Journal of the Korean GEO-environmental Society
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• v.20 no.1
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• pp.27-33
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• 2019

Research was initiated to find out acid drainage neutralizing techniques for ecological vegetative growth on the acid drainage slope. Four different acid drainage neutralizing techniques [no treatment, limestone layer treatment, phosphate treatment, and limestone layer + phosphate treatment] were treated on the acid drainage slope. There was a significant difference observed in treated acid neutralizing techniques for acidity, surface coverage rate, death rate and plant root status. Treated acid neutralizing techniques were effective for neutralizing acidity and vegetative growth in order of [first: limestone layer + phosphate treatment, second: phosphate treatment, third: limestone layer treatment and fourth: no treatment]. The limestone layer and the phosphate treatments were effective for neutralizing acidity and vegetative growth, respectively. However, the phosphate treatment was more effective compared to the limestone layer treatment on the acid drainage slope. We figured out that the phosphate treatment is more effective for neutralizing acidity and vegetative growth because of coating effect of sulfides.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.5
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• pp.1-12
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• 2009

This research was initiated to investigate the revegetation characteristics under the seeding amount treatments of cool-season turfgrasses on the disturbed slope. 4 different seeding amounts of cool-season turfgrasses (0.0 $g/m^2$, 1.5 $g/m^2$, 3.0 $g/m^2$, 6.0 $g/m^2$) with the same seeding amounts of native woody (Rhus chinensis, Albizzia julibrissin) and herbaceous plants (Lotus corniculatus var. japonicus, Dianthus sinensis, Aster yomena) were treated with 3 replications on the experimental disturbed slope. Data such as soil hardness (mm), moisture content (%), surface coverage rate (%), the number of each germinating plant and plant height were analyzed. There were no statistic differences observed in the soil hardness and the soil moisture content while a significant difference was observed in the surface coverage rates. The surface coverage rates were higher in 3.0 $g/m^2$ and 6.0 $g/m^2$ plots compared to the rest two plots of cool-season turfgrasses. However, the emergence of native woody and herbaceous plants was relatively low in 3.0 $g/m^2$ and 6.0 $g/m^2$ plots of high seeding amounts of cool-season turfgrasses. This result indicated that high seeding amounts of cool-season turfgrasses could decrease the emergence of native woody and herbaceous plants. We concluded that 1.5 g~3.0 $g/m^2$ seeding amounts of cool-season turfgrasses was optimum level for the balanced emergence of cool-season turfgrasses, native woody and herbaceous plants in the viewpoint of the ecological disturbed slope revegetation.

• Journal of the Korean Vacuum Society
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• v.13 no.1
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• pp.9-13
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• 2004

Perylene is an interesting material known to have P-type and N-type characteristics at the same time. We prepared perylene thin-films in ultrahigh vacuum with two different deposition rates of 0.1 $\AA$/s and 1.0 $\AA$/s in order to study the dependence of film characteristics on the growth condition. The smaller average grain size with larger surface coverage as well as the better crystallinity were observed on the perylene film prepared under 1.0 $\AA$/s deposition rate in x-ray diffraction (XRD) and atomic force microscopy (AFM) study. For studying electrical property of the film, perylene organic thin-film transistor (OTFT) with gold contacts was fabricated on $SiO_2$/Si surface in UHV condition. The prepared perylene OTFT device shows P-type characteristic. The obtained hole mobility in the current-voltage characteristic curve was$2.23\times10^{-5}\textrm{cm}^2$/Vs.