• Asian Journal of Turfgrass Science
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• v.11 no.3
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• pp.149-159
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• 1997

A study was carried out in order to elucidate utilization of agochemicals in golf courses scien-tifically. The analysis of amounts of agrochemical used in golf courses from 1991 to 1996 which were reported to government are ;Despite of increase of golf courses, the amounts of agrochemicals decreased from 1992 as turning point. The decrease of utilization of insecticides and herbicides made it possible. In fungicides, thiopanate-methyl WP, polyoxine D. thiram WP and iprodione WP were used much in general and their utilization ratios were high. In recent year, as fungicides for Pythium blight and large patch, oxapro WP and pencycuron WP's amounts of utilization increased, but utilization ratios were under 70%. In insecticides, penitrothion OL's quantity consumed and utilization ratios were the best, but showed tendency of decrease as registration of agrochemicals for turfgrass expanded. In herbicides, bensulide OL, napropamide WP, MCPP SL were used much and their utilization ratios were high. In recent year, flazasulfuron WP's amounts of utilization and utilization ratio increased relatively. Key words: Agrochemicals Golf courses, Insecticides, Herbicides,Fungicides.

• Journal of the Korean earth science society
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• v.36 no.5
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• pp.447-459
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• 2015

Dok island comprises Pliocene volcanic products such as a series of volcanoclastic rocks and lavas ranging in composition from alkali basalts, and trachyandesites to trachytes. Compositional variation of the basaltic rocks can be attributed to fractional crystallization of olivine, clinopyroxene, plagioclase, and magnetite. Chemical variations among the trachyandesites are caused by fractionation of clinopyroxene, plagioclase, and magnetite with minor amphibole, while trachytes are controlled mainly by feldspar fractionation. Incompatible element abundance ratios and chondrite normalized LREE/HREE ratios (e.g., (La/Yb)c: 24.8 to 32.8 for basalts, 15.6 to 31.2 for trachyandesites) suggest that the origins of the basalts and trachyandesites involve both different degrees of partial melting and subsequent fractional crystallization processes. Trace element ratios of the basalts from Dok island are characterized by high Ba/Nb, La/Nb, Ba/Th and Th/U and isotopic ratios (Tasumoto and Nakamura, 1991) that are similar to the EM 1 type of oceanic island basalts such as Gough and Tristan da Cunha basalts.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.101-104
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• 2006

This study aims at verifying characteristics of torsional fluctuating moment coefficient and power spectral density, which is needed to estimate torsional response of tall buildings. In order to estimate characteristics, the wind tunnel tests have been conducted on 52 types aero-elastic model of the rectangular prisms with various aspects ratios, side ratios and surface roughness in turbulent boundary layer flows. In this paper, characteristics of torsional fluctuating wind force are briefly discussed and then these results were mainly analyzed as a function of the aspects ratios and side ratios of buildings.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.942-947
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• 2004

The differential equations governing free, in-plane vibrations of stepped non-circuiar arches are derived as nondimensional forms including the effects of rotatory inertia, shear deformation and axial deformation. The governing equations are solved numerically to obtain frequencies and mode shapes. The lowest four natural frequencies and mode shapes are calculated for the stepped parabolic arches with hinged-hinged, hinged-clamped, and clamped-clamped end constraints. A wide range of arch rise to span length ratios, slenderness ratios, section ratios, and discontinuous sector ratios are considered. The effect of rotatory inertia and shear deformation on natural frequencies is reported. Typical mode shapes of vibrating arches are also presented.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.5
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• pp.373-385
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• 2013

To obtain higher power efficiency of Residential Power Generation system(RPG), it is needed to operate system on optimized stoichiometric ratios of fuel and air. Stoichiometric ratios of fuel/air are closely related to efficiency of stack, reformer and power consumption of Balance Of Plant(BOP). In this paper, optimizing stoichiometric ratios of fuel/air are conducted through systematic experiments and modeling. Based on fundamental principles and experimental data, constraints are chosen. By implementing these optimum values of stoichiometric ratios, power efficiency of the system could be maximized.

• Structural Engineering and Mechanics
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• v.28 no.4
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• pp.357-372
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• 2008

This study investigates effect of uncertainty in natural vibration period on the seismic demand. It is shown that since this uncertainty affects the acceleration and displacement responses differently, two ratios, one relating peak acceleration responses and the other relating the peak displacement responses, are not equal and both must be employed in evaluating and defining the critical seismic demand. The evaluation of the ratios is carried out using more than 200 strong ground motion records. The results suggest that the uncertainty in the natural vibration period impacts significantly the statistics of the ratios relating the peak responses. By using the statistics of the ratios, a procedure and sets of empirical equations are developed for estimating the probability consistent seismic demand for both linear and nonlinear systems.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.751-754
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• 2000

In this paper, we propose an efficient method to detect abrupt shot changes in compressed MPEG video data by using reference ratios among video frames. The reference ratios among video frames imply the degree of similarities among adjacent frames by prediction coded type of each frames. A shot change is detected if the similarity degrees of a frame and its adjacent frames are low. This paper proposes an efficient shot change detection algorithm by using Fuzzy c-means(FCM) clustering algorithm. The FCM clustering uses the shot change probabilities evaluated in the mask matching of reference ratios and difference measure values based on frame reference ratios.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.4
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• pp.479-484
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• 2003

In this paper, film thickness and temperature distribution are measured in EHL point contact at high slip ratios. Infrared temperature mapping with two band pass fillers. proposed by Ausherman (1976). is used to measure temperature distribution. And the optical interferornetric method with two filters (red and green filters) is used to measure film thickness. Result of experiment showed that temperature rising at film and ball surface occurred very dramatically in Dimple zone. As slip velocity, slip ratio and load increased, size of Dimple and temperature rising became more large In addition, Position and shape of Dimple we changed by slip ratios, and increasing of Dimple size decreased traction coefficient. In short, it is appointed that the Dimple phenomenon be developed by the effect of viscosity wedge.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.450-457
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• 2020

Single pellet press technology allows for fast, low-cost, and small-scale tests to investigate pelletizing characteristics. We estimated proper compression ratios for five Korean domestic wood species through predicted relationships between pelletizing pressure P_x and compression ratio based on experimental data obtained from a single pellet press unit. The pressures required to obtain a 6-mm-diam pellet of density 1200 kg/㎥ were estimated as 111 MPa for Populus davidiana, 133 MPa for Robinia pseudoacacia, 136 MPa for Quercus mongolica, 97 MPa for Pinus densiflora, and 127 MPa for Pinus rigida. On the basis of these pressures, we estimated proper compression ratios to be within the range 7.676-8.410 for these species, and we found the compression ratios needed for hardwood species to be somewhat higher than those needed for softwood species to obtain the pellet density of 1200 kg/㎥.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.4
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• pp.67-74
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• 2006

This study was carried out to investigate the liquefaction behaviour of saturated silty sand under monotonic loading conditions. The undrained soil tests were conducted using a modified triaxial cell and specimens were prepared using the moisture tamping method. Undrained triaxial compression tests were performed at different confining pressures, void ratios and overconsolidation ratios and the samples were sheared to axial strains of about 20% to obtain monotonic loading conditions. It is shown that increasing confining pressures, void ratios and overconsoildation ratios increases the deviator stress, but it has no effect on increasing the dilatant tendencies. It is shown that complete static liquefaction was observed regardless of increases in the confining pressure, void ratio and overconsolidation ratio. Therefore, the confining pressure, void ratio and overconsoildation ratio does not provide significant effects on the liquefaction resistance of the silty sand. The presence of fines in the soil was shown to greatly increase the potential for static liquefaction and creates a particle structure with high compressibility for all cases.