• Journal of Surface Science and Engineering
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• v.23 no.2
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• pp.18-23
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• 1990

Thin films of tin oxide were prepared by chemical vapor deposition (C.V>D) using the hydrolysis reaction of SnCl4, Deposition rate increased with the increase of temperature up to $500^{\circ}C$and then decreased at $700^{\circ}C$, Deposition rate with SnCl4 partial pressure showed RidealEley behavir. It was found that SnO2 thin film deposited at the temperature above $400^{\circ}C$ had(110) and (301) plane preferred orientation with crystallinity of rutite structure. Electrical resisvity of SnO2 thin film decreased with increase increase of deposition temperature and showed minimum value of 10-3 ohm at $500^{\circ}C$and than largely increased increased with further increase of deposition temperture.

• Journal of the Korean Wood Science and Technology
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• v.51 no.2
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• pp.98-108
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• 2023

In this study, the boards were manufactured according to the mandarin peels addition rate using sawdust and mandarin orange peel. After that, the mechanical properties and density profile of ceramics prepared by conditions through resin impregnation process and carbonization process were investigated. The bending and compression strengths of ceramics tended to increase as the resin impregnation rate increased. When the resin impregnation rate was 70%, the highest values were 8.58 MPa and 14.77 MPa, respectively. Also, the mechanical properties of ceramics according to carbonization temperature showed the highest values at 1,200℃ for bending strength of 11.09 MPa and compression strength of 17.20 MPa. The bending strength and compression strength according to the mandarin peels addition rate showed the highest values at 8.62 MPa and 14.16 MPa, respectively, when the mandarin orange peel addition rate was 5%. The mechanical properties tended to decrease when the addition rate of mandarin orange was increased. The density profile of ceramics showed a similar tendency to the mechanical properties. It can be seen that the density distribution from the surface layer to the center layer is more uniform as the resin impregnation rate and carbonization temperature increase and the mandarin peels addition rate decreases.

• Journal of the Korean Society of Tobacco Science
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• v.8 no.1
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• pp.41-48
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• 1986

This experiment was carries out to study on the effect of temperature raising rate to chemical composition of tobacco leaves during the midrib drying stage of flue-curing. The results were as follows : In the case of the temperature raising rate became more rapidly during midrib drying stage. It had a tendency to increase in oxailic acid, succinlc acid, ammonia, polyphenol; there was a large loss of total sugar, reducing sugar, malic acid, palmitic acid and linolenic acid; leaf color became more reddish; the leaf quality index value decreased, thereby the quality of external appearance deteriorated. It is desirable that the temperature raising rate had to be more slowly.

• Journal of the Korean Ceramic Society
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• v.33 no.7
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• pp.809-815
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• 1996

When Li2O.2SiO2 glass was crystallized between the temperature of maximum nucleation and the temperature of maximum crystal growth it was found that the control of heating rate had serious effect on the crystallinity and microstructure and the greatly changed physical properties. Density and elastic modulus tends to increase but thermal expansion coefficient decreased with increased crystallinity. When heating rate between the tempe-rature of maximum nucleation and the temperature of maximum crystal growth was 10~5$0^{\circ}C$/hr. crystallinity was increased to result in the increment of strength. When nuclation was done at 44$0^{\circ}C$ for 5 hours and the temperature of crystal growth was held at 575$^{\circ}C$ strength was increased until crystallinity reached 65% and strength was decreased with higher crystallinity. These phenomena could be explained that even for the same crystallinity different heat rates resulted in different number and size of cracks.

• Structural Engineering and Mechanics
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• v.80 no.5
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• pp.539-551
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• 2021

With the continuous increase of computational capacity, more and more complex nonlinear elastoplastic constitutive models were developed to study the mechanical behavior of elastoplastic materials. These constitutive models generally contain a large amount of physical and phenomenological parameters, which often require a large amount of computational costs to determine. In this paper, an inverse parameter determination method is proposed to identify the constitutive parameters of elastoplastic materials, with the consideration of both strain rate effect and temperature effect. To carry out an efficient design, a hybrid optimization algorithm that combines the genetic algorithm and the Nelder-Mead simplex algorithm is proposed and developed. The proposed inverse method was employed to determine the parameters for an elasto-viscoplastic constitutive model and Johnson-cook model, which demonstrates the capability of this method in considering strain rate and temperature effect, simultaneously. This hybrid optimization algorithm shows a better accuracy and efficiency than using a single algorithm. Finally, the predictability analysis using partial experimental data is completed to further demonstrate the feasibility of the proposed method.

• Corrosion Science and Technology
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• v.19 no.6
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• pp.281-287
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• 2020

Chloride ion is one of the most important corrosive agents in atmospheric corrosion, especially in marine environments. It has high adsorption rate and increases the conductivity of electrolytes. Since chloride ions affect the protective properties and the surface composition of the corrosion product, they increase the corrosion rate. A low level of chloride ions leads to uniform corrosion, whereas a high level of chloride ions may induce localized corrosion. However, higher solution temperatures tend to increase the corrosion rate by enhancing the migration of oxygen in the solution. This work focused on the effect of NaCl concentration and temperature on galvanic corrosion between A516Gr.55 carbon steel and AA7075T6 aluminum alloys. When AA7075T6 aluminum alloy was galvanically coupled to A516Gr.55 carbon steel, AA7075T6 was severely corroded regardless of NaCl concentration and solution temperature, unlike the corrosion properties of single specimen. The combined effect of surface treatment involving carbon steel and aluminum alloy on corrosion behavior was also discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.3 s.234
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• pp.402-408
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• 2005

The instantaneous temperature behaviors on impinging plate in case of ultra high pressure have been measured and analyzed by using the instantaneous temperature probe and ultra high pressure injection equipment. The temperature drop was largest at P1 which is center of impinging spray and decreased with propagation of spray to the radius direction. The temperature drop was bigger in case of higher temperature of impinging plate. The temperature drop decreased with increase of injection pressure. But decreasing rate of temperature drop was slight over 2,500 bars. Therefore, it was predicted that the fuel evaporation versus the increase of injection pressure was maximum at around 2,500 bars.

• Journal of Surface Science and Engineering
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• v.24 no.4
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• pp.179-186
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• 1991

The effects of silicone contents and flow rates(agitation rates) of electrolyte on the formation and mechanical properties of hard anodized film of Al-Si alloy have been studied in 12% H2SO4 + 1% Oxalic acid with varying the silicone contents in the rance of 0 to 11.6% and the flow rates of electrolyte in the range of 0 to 90cm/sec. The film forming voltage required to maintain an equivalent current density significantly increase with the silicone content of Al-Si alloys due to a low conductivity of silicone. Hardness and wear resistance of the anodized film of Al-Si alloys decreases wit increasing the silicone content. The increase in the flow rate of electrolyte has a similar influence on the formation and mechanical properties of anodized film as does the decrease in bath temperature. Hardness of anodized film is rapidly increased with the flow rate being increased from 10cm/sec. It is observed that the increase in the flow rate from 11cm/sec. It is observed that the increase in the flow from 11cm/sec to 48cm/sec is more effective in enhancing the hardness of film than is the decrease in bath temperature from 1$0^{\circ}C$ to $0^{\circ}C$.

• Journal of Power System Engineering
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• v.8 no.3
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• pp.36-43
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• 2004

The effect of bath composition, plating condition and plating rate on the magnetic property of electroless Co-Cu-P deposits were investigated. With increasing $CuCl_2$ concentration in the bath, plating rate increased, while the Br value of deposit decreased sharply. Deposited surface were inferiority by the increase pH above 10.5, bath temperature higher than $80^{\circ}C$. Plating reaction had been ceased by the increase of pH above 11, bath temperature higher than $90^{\circ}C$ and under $40^{\circ}C$. The Br value of deposit was uniform with various concentration of complexing agent(sodium citrate) in the bath. The Br value of deposit was almost equal to that found by the addition of stabilizer (thiourea) and accelerator(NaF). The Br value of deposit was uniform in plating time(20min) and heat treatment temperature(below $200^{\circ}C$), and were confirmed to have adequate bath stability for practical use.

• Asian Journal of Turfgrass Science
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• v.3 no.1
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• pp.24-33
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• 1989

This study was conducted to investigate the effect of paclobutrazol [(2 RS , 3 RS )1-(4- chlor-ophenyl )-4, 4- dimethyl -2- (1, 2, 4- triazol -1- yl )- pentan -3-01] on the tolerance of hi-gh temperature and drought stress as related to growth retardation , iranspiration rate , soil water content , nitrogen level and photosynthetic rate in perennial ryegrass ( Loliurn perenne L . ' Omega H , ). Plants were given a 30 ml soil drench of paclohutrazol at the concentrations of 0, 0.01, 0.1, 1.0, 10.. 0, mg / 6 .5cm- diameter pot . The rcsults were as follows : 1. Increasing concentrations of paclohutrazul reduced plant height , leaf area , fresh weight and dry weight , hut increased chlorophyll content per unit area . The number of tillers and leaf width were not affected hy the paclobutrazol concentrations . 2. The proper concentration of paclohatrazol on growth retardation in perennial ryegrass was about I mq /pot , hut leaf deformity and severe growth retardation were shown at high concentration of 10 mq / pot . 3. Perennial ryegrasses grown at 30˚C were shown significantly short plant height and low leaf nitrogen level compared with those grown at 20˚C. Increasing concentrations of paclohutrazol at 20˚C increased nitrogen level hut it could not increase nitrogen level at 30˚C . 4. During the drought stress , increasing temperatures significantly promoted transpiration rate and wilting time . It took about 5 days at 20˚C and 3 days at 30˚C to reach wilting time of leaves from water stress treatment . Soil water contents at wilting time of non-treated controls were averaged 6. 871% at 20˚C and 6. 17% at 30˚C 5. Paclohutrazol reduced transpiration rate at high temperature and drought stress . Wilting appeared at the lower water content of soil according to increasing concentrations of paclobutrazol at 30˚C hut there were no differences among concentrations of at 20˚C. 6.Paclohutrazol treatment at 1 rag /pot reduced injury rate of leaves from 67.1 % and 100 % in control plants to 15.7% and 80% at 20˚C and 3010, respectively. 7. Photosynthetic rate per unit area was significantly reduced at high temperature . Paclohutrazol stimulated photosynthetic rate with increase of concentrations at 20˚C but there was no increasing effect at 30˚C.