• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.1
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• pp.46-51
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• 1983

This study practiced to observe the creep behavior at specific temperature on Austentic SUB 27 stainless steel by Moire method. The results obtained from this study are summarized as follows; In tensile experiment, tensile strength and yielding strength decrease as the temperature increases. Yielding strength is equivalent to 60-70% of tensile strength. Reduction of Area and Elongation show minimum values at 300.deg. C. The results of Moire method using Moire heating resisting grid coincide with LVDT result. Therefor, It is proved that the Moire method has great merit in strain measurement of a creep behavior. In homologous at temp. 0.2 or less, creep behavior is very small amount. But, in more than 0.3, creep behavior is very active. Creep rate increase as temperature increase and creep rate is proportional to .alpha. values of experimental equation.

• The Korean Journal of Applied Statistics
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• v.22 no.1
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• pp.221-235
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• 2009

This manuscript illustrates the comparative study between ARIMA and Exponential Smoothing modeling to develop forest fire forecasting system using different weather parameters. In this paper, authors have developed the most suitable and closest forecasting models like ARIMA and Exponential Smoothing techniques using different weather parameters. Authors have considered the extremes of the Wind speed, Radiation, Maximum Temperature and Deviation Temperature of the Summer Season form March to June month for the Ranchi Region in Jharkhand. The data is taken by own resource with the help of Automatic Weather Station. This paper consists a deep study of the effect of extreme values of the different parameters on the weather fluctuations which creates forest fires in the region. In this paper, the numerical illustration has been incorporated to support the present study. Comparative study of different suitable models also incorporated and best fitted model has been tested for these parameters.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.1
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• pp.69-76
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• 2002

Mustard aphid, Lipaphis erysimi(Kalt.) plays a key role in determining the productivity of rapeseed-mustard. This pest alone attributes 30-70% losses in yield potential in different agro climatic zones with a mean loss of 54.2% in India. Considering the extent of damage caused by the pest, the present experiment was conducted at Pulses and Oilseeds Research Station during 1992-93 to 1994-95 to study the migratory nature of mustard aphid by trapping them in yellow colour pan tray and their simultaneous growth and development on three different genotypes. The temperature during noon hours is the predominant factor to govern the appearance of alate mustard aphid in rapeseed-mustard field. Stepwise regression analysis revealed that temperature and relative humidity played an important role for its development. The variety RW white flower glossy stem harboured minimum number of aphid in comparison to other two varieties B 9 and T6342. The population reached a peak of 61.28 aphids/10 cm central twig during $6^{th}$ standard week irrespective of varieties.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.E1
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• pp.13-21
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• 2005

Atmospheric concentrations of PCBs were monitored in Ansung-city, Kyonggi province during the 2001/2002 to characterize the concentration distribution and seasonal variation of particle polychlorinated biphenyls (PCBs). Average concentration of particle bound PCB showed maximum value for penta-CBs and minimum value for octa-CBs. Seasonal contributions $(%\)$ of total particle PCBs showed the highest value in winter months and lowest value in summer month, This result indicated that concentration of total particle PCBs increased with decreasing temperature in the atmosphere. Therefore, particle PCBs were easily formed by the condensation of gas phase PCBs in winter months. The total particle PCBs exhibited an inverse correlation with temperature (p<0.01) which suggested that particle PCBs were easily formed by condensation of gaseous PCBs in winter months.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.7-14
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• 2004

The lift-off characteristics of the triple flame have been studied experimentally with various mean velocities and concentration gradients using a multi-slot burner, which can control the concentration gradient and the mean velocity independently, Lift-off height, axial maximum velocity, flame temperature, and some other characteristics were examined for methane and propane flame, It was found that minimum values of the lift-off heights exist at a certain concentration gradient for constant mean velocity, and this result implies that the propagation velocity has a maximum value at this condition, OH radical distribution was measured with LIF method and velocity variation along streamline was measured with PlV system. In addition maximum temperature along streamline was measured with CARS system. The intensity of the diffusion flame affects on the propagation velocity of triple flame in the region of very weak concentration gradient.

• Tribology and Lubricants
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• v.20 no.2
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• pp.84-90
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• 2004

It is very important to improve the durability and reliability of crankshaft because of conflicting demands for lower fuel consumption and higher power output. In this study, for the crankshaft bearing design, analyses were conducted to determine the lubrication characteristics such as oil flow rate, minimum oil film thickness, friction force and increase of oil temperature at main bearing and connecting rod bearing. Additionally, supplied oil pressure and temperature effects on the bearings were simulated to figure out lubrication characteristics on the bearings. Finally the effects of increasing the bearing width and clearance were introduced on the lubrication characteristics.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.10
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• pp.1545-1553
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• 1989

The ohmic contact behavior in HEMT structure was compared with that in MESFET one throughout the specific contact resistance and microstructural change in both structures. A Au-Ge-Ni based metallization scheme was used and the alloying temperature of the ohmic materials was changed from 330\ulcorner to 550\ulcorner. The alloying temperature to obtain the minimum specific contact resistance in HEMT structure was 60k higher than that in MESFET. The volume fraction of NiAs (Ge) in MESFET structure increases with alloying temperature and/or the alloying time, which makes the decrease of specific contact resistance at the initial stage of ohmic metallization. In contrast, the volume fraction of NiAs(Ge) in HEMT structure was not dependent upon the specific contact resistance, which implies that the ohmic contacts are dominantly formed by the Ge diffusion to 2-DEG(two dimensional electron gas) layer.

• Transactions of Materials Processing
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• v.21 no.2
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• pp.101-106
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• 2012

Generally, rapid cure reaction of LED encapsulation silicone resin causes serious defects in cured resin products such as warpage, residual bubbles, and reduced wettablility. In order to prevent residual bubbles in silicone resin, the step cure process was examined in the present paper. Three kinds of step cure processes were applied, and bubble-free phenomenon was observed. Most of the bubbles were removed under $70^{\circ}C$, the minimum temperature for activating cure reaction. In addition, degree of cure(DOC) and temperature distribution were predicted by using FEM analysis of heat transfer. It was concluded that maintaining cure temperature which provide a DOC under 0.5~0.6 effectively reduces residual bubbles.

• Progress in Superconductivity and Cryogenics
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• v.1 no.2
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• pp.49-53
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• 1999

We fabricated a resistive superconducting fault current limiter (SFCL) with a shunt resistor in order to bypass the transient current at faults. The SFCL consists of a YBCO films coated with an Au layer (10$\Omega$ at room temperature). which is to disperse the heat generated at hot spots in the YBCO films, and a 5$\Omega$ shunt resistor. The minimum quench current of the SFCL was found to be 12.2Apeak. This SFCL successfully controlled the fault current to below 23 Apeak. Which is otherwise to increase up to 103 Apeak. With the shunt resistor, the temperature of the SFCL rose the temperature of the SFCL rose three times slower than without the shunt, whereby the SFCL is protected at high currents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.8
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• pp.835-839
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• 2004

The surge characteristics of ZnO varistors consisting of $ZnO-{Pr}_6{O}_11-CoO-{Cr}_2{O}_3-{Er}_2{O}_3$ceramics were investigated at various sintering temperatures. As sintering temperature raises, the varistor voltage was decreased from 341.2 to 223.1 V/mm, the nonlinear exponent was decreased from 64,9 to 44.1. On the other hand, the leakage current exhibited a minimum(0.64 $\mu$A) at 134$0^{\circ}C$, The clamping capability was slightly deteriorated with increasing sintering temperature. On the whole, the ZPCCE-based ZnO varistors exhibited good clamping voltage characteristics as exhibiting the clamping voltage ratio of 1.85 ∼ 1.92 approximately at surge current of 100 A.