• Journal of the Korean Wood Science and Technology
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• v.12 no.4
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• pp.12-18
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• 1984

Soaking treated in 20% aqueous solutions of $(NH_4)_2SO_4$, $NH_4H_2PO_4$, $(NH_4)_2HPO_4$, $Na_2B_4O_7-H_3BO_3$(60:40) and Minalith, the mixed salts for 9 hrs. the wet 3.5mm meranti (Parashorea spp.) plywoods were press-dried at 90, 120 and $150^{\circ}C$ and put to static bending test to examine the influence of redrying temperature on the strength of fire-retardant treated plywoods ill flexure. While water-soaking treatment (control) showed serious reduction in Stress at proportional limit, MOE, MOR, Work per unit volume at $150^{\circ}C$, all the fire-retardant treatments maintained bending strength even at $150^{\circ}C$ and showed rather increased values in case of some chemicals. In view of drying rate and maintenance of strength, the most pertinent platen temperature was $150^{\circ}C$ and Borax-Boric acid was the predominant fire-retardant in this study.

• Journal of the Korean Geotechnical Society
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• v.39 no.12
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• pp.7-22
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• 2023

In this study, the limit range of input acceleration was investigated based on time domain and response spectrum analyses by considering the relative density, groundwater depth, and soil type. Special attention was paid to the input acceleration and shear modulus of soil, which affect pile behavior. The surrounding soil was identified as an elastoplastic material and subjected to FLAC3D analysis using the Mohr-Coulomb and Finn models as well as FB-Multiplier analysis using a nonlinear p-y curve for soil spring. Based on the analyses, the limit range of acceleration on the pile is much higher for SP soil than for SM soil, and the groundwater level tends to reduce the limit range of input acceleration, irrespective of soil conditions. The limit range of acceleration was mainly affected by the shear modulus. The limit range of acceleration with nonlinear soil behavior is proportional to the relative density of the surrounding soil.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.6
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• pp.59-66
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• 2001

Fatigue strength of the welding structure is governed by the residual stress at the weldment toe and static tensile overloads were known as relieving the residual stresses. In this study, static tensile overloads were applied to the welding structures which caused the relief of residual stresses. The amount of residual stress relief was found as proportional to the change of fatigue limit at the given conditions. Based on the fact of the proportionality between the change of fatigue limit and that of residual stress, simple measurement technique is proposed. Modified stress-life curves base on proposed technique gave good agreement with test results.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.7-12
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• 2003

Mixture formation in the cylinder of a lean bum engine has been observed by Laser Induced Fluorescence technique. XeCl laser (308nm) was used to produce a laser sheet. 3-pentanone has been added to iso-octane fuel to produce fluorescence, the intensity of which is proportional to the concentration of the fuel. The laser sheet was introduced through the piston window and the fuel distribution in the vertical plane was observed through a side window. Comparison has been made for the cases of selected fuel injection timing as 0, 360, 405, and 450 CA. For the case of 0 and 360 CA injection, uniform fuel distribution in the combustion chamber has been obtained at the ignition time which is favorable for the high load mode. And the late injection cases, 405 and 450 CA, revealed the stratified formation of rich mixture around the spark plug. That extends the lean misfire limit and reduces cyclic variation in the low load mode.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.8
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• pp.316-322
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• 1986

In this paper, the photodoping effect on the interface of Ag-amorphous As2S3 thin film has been investigated by measuring the resistance change of the Ag layer, the absorption coefficient of the As2S3, the optical density of As2S3 layer and the short-circuit photocurrents under light irradiation. As the experimental results, the photodissolution rate and the photodiffusion rate depends on the magnitude of photon energy absorbed in the As2S3. The sensitivity limit of the photodissolution rate at Ag layer was about 630[nm] and the sensitivity limit of the photodiffusion rate at the Ag-As2S3 interface was about 680[nm]. Also, it was found that the depth of photodiffusion was proportional to the square root of exposing time.

• Analytical Science and Technology
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• v.9 no.3
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• pp.262-269
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• 1996

The muiltiwire proportional counter for the measurement of low-level and environmental $\alpha$ particles emitting nuclides was developed. External dimension of the devloped multiwire proportional counter is $350{\times}290{\times}30mm$ and the sensitivity area is $250{\times}200mm$. The wall material of the detector was selected the stainless steel to prevent the deformation by external impact and to obtain minimum background. The anode and cathode wires were used the stainless steel material of diameter $50{\mu}m$. The spacing of each wires are 10.0mm, 5.0mm and the numbers of total wire are 21, 42 lines, respectively. The multiwire proportional counter was designed that the measurement source is placed within the detector to prevent the wall absorption effect and the efficiency variation by various source heights. The characteristics of the developed detector have been investigated to obtain the plateau, operating voltage, background, counting efficiency, position sensitivity and energy resolution etc. For the $^{241}Am$ nuclide, the calculated LLD(Lower Limit of Detection) is 5.0mBq/L which is lower than 40mBq/L of recommended LLD value by ISO(International Organization for Standardization).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.377-380
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• 1998

Basting vibration and air blast were measured by particle velocity and overpressure as well as environmental unit, dB(V) and dB(A). Variables for vibration and noise show good relationship and proportional equations are suggested. But there are some variations, and it means that predictions by design variables are not valid for human damage estimation or limit application of regulations.

• Archives of Pharmacal Research
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• v.11 no.1
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• pp.56-60
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• 1988

A thin layer flow cell with cell volume of $8\;{\mu}{\ell}$ was constructed. Diffusion currents of ascorbic acid was directly proportional to the 1/3 power of volume flow rates. A linear dynamic range was obtained at the concentration range between $10^{-7}\;M\;and\;10^{-4}\;M$ of ascorbic acid with a detection limit of $10^{-8}\;M$. Ascorbic acid in the multivitamin product was amperometrically determined at TLFC after simply dissolving mg range ground product in $100m{\ell}$ of pH 7.0 phosphate buffer.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.99-105
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• 2004

The effects of pressure on combustion characteristics of the conical flameholder were investigated experimentally in the pressure range from 0.11 ㎫ to 0.40 ㎫. The result shows that the total equivalence ratio of lean limit becomes lower as the combustor inlet pressure rises and NOx emission is proportional to the pressure to the 0.5th power.

• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.597-606
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• 2021

Due to the characteristics of the farmland in Korea, forward and reverse shift is the most used. The fatigue of farmers is caused by forward and reverse shifting with a manual transmission. Therefore, it is necessary to improve the convenience of forward and backward shifting. This study was a basic study on the development of a current control system for forward and reverse shifting of agricultural tractors using proportional control valves and a controller. A test bench was fabricated to evaluate the current control accuracy of the control system, and the stability of the controller was evaluated through CPU (central processing unit) load measurements. A controller was selected to evaluate the stability of the proportional valve controller. The stability evaluation was performed by comparing and analyzing the command current of the controller and the actual current measured. The command current was measured using a CAN (controller area network) communication device and DAQ (data acquisition). The actual current was measured with a current probe and an oscilloscope. The control system and stability evaluation was performed by measuring the CPU load on the controller during control operations. The average load factor was 12.27%, and when 5 tasks were applied, it was shown to be 70.65%. This figure was lower than the CPU limit of 74.34%, when 5 tasks were applied and was judged to be a stable system.