• Journal of Information Display
• /
• v.7 no.1
• /
• pp.25-29
• /
• 2006

By the voltage threshold (Vt) close-curve measurement method, the changes in the discharge characteristics such as a firing voltage and IR emission among the three electrodes were examined relative to the low or high panel temperature ranging from -10 to $80^{\circ}$. The variation in the panel temperature was found significantly influence the surface discharge between the MgO surfaces rather than the plate gap discharge between the MgO and phosphor layers. Based on this experimental observation, a modified reset waveform that alleviates the surface discharge during a ramp-up and -down period was deeloped. By adopting the proposed reset waveform, a stable address discharge could be obtained irrespective of the panel temperature variation.

• Journal of Biosystems Engineering
• /
• v.37 no.2
• /
• pp.75-81
• /
• 2012

Oyster mushroom farm which could not meet optimum temperature range yields non-uniform sized, low quality products. Thus, this study, utilizing STAR CCM+, one of the computational fluid dynamics (CFD) programs, analyzed the impact of air circulation and temperature distribution. Methods: After we visited numerous mushroom farms, we measured the temperature at the discharge ports of heaters, fan capacity, and the locations of the air circulators in the farms. According to the data, most mushroom growers installed the heaters near the entrance and discharge ports of the heaters at the third growing bed on the same height as the heaters in the entrance. The temperature at the discharge port of heater was $1,26^{\circ}C$, and the fan capacity was 4,500 $m^3$/hr. The air circulator was placed in the center of the mushroom farm 50cm above the ground, and its capacity of inlet port was 1,100 $m^3$/hr and discharge port 1,600 $m^3$/hr. The mushroom farm was insulated. Results: According to the analysis of the temperature distribution in the vertical plane of the entrance side, no air circulation causes the high temperature zone of 296~299K at the discharge port of the heater to take up 34% of area while the operation of air circulators causes it to occupy only 9%. This means that not using air circulators leads to a concentration of high temperature at the discharge port near the entrance. In addition, with the results of the analysis of the temperature distribution in the vertical planes of the center, no air circulation causes the temperature zone of 295~298K at the discharge port of the heater to take up 48% of area while the operation of air circulators causes it to occupy 80%. This shows that the high outlet port temperature disseminated to the center. Conclusions: After ninety minute operation of both heater and air circulator, the interior temperature became stabilized in the mushroom farm. Air circulation made the high temperature at the discharge port disseminate to the center and exit in the farm and equalize the temperature distribution.

• Proceedings of the KIEE Conference
• /
• 1998.07e
• /
• pp.1708-1710
• /
• 1998

In this study, several experiment is executed to analyze properties of Electrodeless Discharge Lamp using H-Discharge. 1. The operating frequency of this lamp is $2.45{\sim}2.65$[MHz] 2. The color of light is mild-white. And, it is shifted in the direction of red in low temperature. 3. In ambient temperature under $10^{\circ}C$, luminous efficiency is decreased precipitously. Therefore, research for improvement discharge-characteristic in low temperature need. 4. Discharge-characteristic stable between $160{\sim}240$[V]. And, luminous output is inverse proportion to coil-voltage. 5. When input-voltage is decreased continuously unstable section exist.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.08a
• /
• pp.72-75
• /
• 2003

Effects of delay and panel temperature on the discharge time lag and the controllability of weak discharge mode were studied under single cell driving circumstances of ac PDP. It was found that sufficient number of priming particle is necessary for inducing weak discharge in ramp voltage driving. Discharge time lag was reduced dramatically under elevated panel temperature condition It is speculated that decrement of discharge time lag at the high temperature is related to the reduction of diffusion loss of charged particles during the after glow.

• Proceedings of the KIEE Conference
• /
• 2003.07c
• /
• pp.1686-1688
• /
• 2003

Effects of delay and panel temperature on the discharge time lag and the controllability of weak discharge mode were studied under single cell driving circumstances of at PDP. It was found that sufficient number of priming particle is necessary for inducing weak discharge in ramp voltage driving. Discharge time lag was reduced dramatically under elevated panel temperature condition. It is speculated that decrement of discharge time lag at the high temperature is related to the reduction of diffusion loss of charged particles during the after glow.

• Journal of Energy Engineering
• /
• v.15 no.3 s.47
• /
• pp.154-159
• /
• 2006

An experimental study has been performed to investigate the correlation on compressor discharge temperature of capacity modulated system A/C in cooling mode. Indoor and outdoor temperatures, the cooling capacity, compressor discharge temperature and loading time are measured by the psychrometric calorimeter. The system is controlled by applying the scroll compressor operated by PWM valve and loading duty. With decreasing outdoor temperature, the cooling capacity increases. But, with decreasing indoor temperature, it decreases. According to the increase in outdoor temperature and loading duty, compressor discharge temperature increases. From these experimental data, the correlation on compressor discharge temperature is proposed. The correlation obtained from the present study is agreed with the experimental data within $3^{\circ}C$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.5
• /
• pp.397-405
• /
• 2003

Heat and fluid flow in a compressor into which liquid refrigerant is injected for the purpose of reducing discharge gas temperature in a heat pump system has been numerically studied. A mechanistic approach encompassing liquid jet breakup and droplet evaporation has been performed to investigate the effects of liquid injection on the spacial and temporal variation of the gas temperature and pressure inside the compressor cylinder. Various parameters, such as liquid injection mass, time, duration and droplet size, are considered in the present study to elucidate the flow field inside the compressor. As the injection mass is increased, discharge gas temperature is decreased, while the pressure is increased due to the added mass of the injection. For the injected liquid mass corresponding to 15% of the total vapor mass in the cylinder, the discharge gas temperature drops by 22.4 K. It is observed that the droplet size plays a major role in the evaporation rate of the droplets that determines the degree of the discharge temperature drop.

• Transactions on Electrical and Electronic Materials
• /
• v.11 no.1
• /
• pp.42-47
• /
• 2010

Polymer insulating materials such as cross linked polyethylene (XLPE) are employed in electric cables used for extra high voltage. These materials can degrade due to chemical, mechanical and electric stress, possibly caused by voids, the presence of extrinsic materials and protrusions. Therefore, this study measured discharge patterns, discharge phase angle, quantity and occurrence frequency as well as changes in XLPE under different temperatures and applied voltages. To quantitatively analyze the irregular partial discharge patterns measured, the discharge patterns were examined using a statistical program. A three layer sample was fabricated, wherein the upper and lower layers were composed of non-void XLPE, while the middle layer was composed of an air void and copper particles. After heating to room temperature and $50^{\circ}C$ and $80^{\circ}C$ in silicone oil, partial discharge characteristics were studied by increasing the voltage from the inception voltage to the breakdown voltage. Partial discharge statistical analysis showed that when the K-means clustering was carried out at 9 kV to determine the void discharge characteristics, the amount discharged at low temperatures was small but when the temperature was increased to $80^{\circ}C$, the discharge amount increased to be 5.7 times more than that at room temperature because electric charge injection became easier. An analysis of the kurtosis and the skewness confirmed that positive and negative polarity had counterclockwise and clockwise clustering distribution, respectively. When 5 kV was applied to copper particles, the K-means was conducted as the temperature changed from $50^{\circ}C$ to $80^{\circ}C$. The amount of charge at a positive polarity increased 20.3% and the amount of charge at a negative polarity increased 54.9%. The clustering distribution of a positive polarity and negative polarity showed a straight line in the kurtosis and skewness analyses.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.14 no.8
• /
• pp.663-669
• /
• 2001

Spinel LiM $n_2$ $O_4$ and LiM $n_{1.9}$M $g_{0.1}$ $O_4$ power was synthesized with solid-state method by calcining the mixture of LiOH.$H_2O$, Mn $O_2$ and MgO at 80$0^{\circ}C$ for 36 h in an air atmosphere. To investigate the effect of temperature on he cycle performance of cathode material during cycling, charge-discharge experiments and ac impedance measurement were performed. Initial discharge capacity was gradually increased with the increase of charge-discharge temperature. Discharge capacity at high temperature was suddenly decreased during cycling. On the other hand, discharge capacity at low temperature was almost constant during cycling. It confirmed that Mn dissolution is serious at high temperature than at low temperature. LiM $n_2$ $O_4$ and LiM $n_{1.9}$M $g_{0.1}$ $O_4$ showed the best capacity and stability at room temperature.ure.ure.

• Solar Energy
• /
• v.9 no.1
• /
• pp.70-77
• /
• 1989

Sodium pyrophosphate that melting point is $79-80^{\circ}C$ have been Studied on heat storage and heat discharge. In heat storage process, sodium pyrophosphate was kept up initial temperature $50^{\circ}C,\;60^{\circ}C,\;70^{\circ}C$ which melt by heated water at temperature $85^{\circ}C,\;90^{\circ}C,\;95^{\circ}C$. In heat discharge process, initial temperature of sodium pyrophosphate was maintained at temperature $85^{\circ}C,\;90^{\circ}C,\;95^{\circ}C$ which varied cooling temperature $50^{\circ}C,\;60^{\circ}C,\;70^{\circ}C$. The experiment has been reached conclusions as follows. 1) Heat transfer properties of phase change material is controlled by conduction during heating and cooling process. 2) The temperature increased rapidly at initial stage and transient region increase slowly because of characteristic of latent heat. 3) The lower cooling water temperature is the less the time that get to thermal equivalent state take during discharge process. 4) The higher cooling water temperature is the less temperature difference between top and bottom in P.C.M during discharge process.