• 전기학회논문지
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• 제56권7호
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• pp.1255-1260
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• 2007

[ $TiO_2-V_2O_5$ ] sol was prepared using sol-gel method. Sol changed to gel with hydrolysis and polymerization. DTA properties of gel powder had endothermic reaction due to evaporation of propanol about $80^{\circ}C$, had exothermic reaction due to combustion of propanol about $230^{\circ}C$ and had exothermic reaction due to combustion of alkyl group about $350^{\circ}C$. Crystalline properties of gel powder retained amorphous phase at $50^{\circ}C$, retained anatase phase from $400^{\circ}C\;to\;600^{\circ}C$ and had all rutile phase over $700^{\circ}C$ at 0.01mole $V_2O_5$ additive. The capacitance of thin films increased with increasing heat treatment temperature and thin films had best properties at $700^{\circ}C$. The capacitance of thin films increased a lot with decreasing measurement frequency.

• 한국입자에어로졸학회지
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• 제13권4호
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• pp.165-172
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• 2017

For precise particle measurements in combustion environments, various dilution sampling methods were compared. Dilution equipments using dilution tunnels and hot/cold dilution with porous tube dilutors were most frequently used so far. The combination of porous tube dilutor and ejector diluter has relatively small footprint, and it results in lower particle losses compared to other methods. To determine the portion of condensable particulate matter, proper temperature control and flow control is required.

• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.195-199
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• 2003

The stoichiometric methan/air premixed turbulent flames at the axisymmetric Bunsen burner situation are numerically investigated. To account for the chemistry-turbulence interaction in the turbulent premixed flames, the steady laminar flamelet library method has been adopted. The flame front is tracked by using the Level-Set Approach. Turbulence is represented by the ${\kappa}-{\varepsilon}$ modeling with a Pope's correction. The detailed comparison between prediction and measurement has made for the flame field in terms of velocity, turbulent kinetic energy, and normarlized temperature.

• 한국안전학회지
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• 제31권5호
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• pp.42-48
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• 2016

The usage of the correct combustion properties of the treated substance for the safety of the process is critical. For the safe handling of n-nonane being used in various ways in the chemical industry, the flash point and the autoignition temperature(AIT) of n-nonane was experimented. And, the explosion limit of n-nonane was calculated by using the flash point obtained in the experiment. The flash points of n-nonane by using the Setaflash and Pensky-Martens closed-cup testers measured $31^{\circ}C$ and $34^{\circ}C$, respectively. The flash points of n-nonane by using the Tag and Cleveland open cup testers are measured $37^{\circ}C$ and $42^{\circ}C$. The AIT of n-nonane by ASTM 659E tester was measured as $210^{\circ}C$. The lower explosion limit by the measured flash point $31^{\circ}C$ was calculated as 0.87 vol%. And the upper explosion limit by the measured upper flash point $53^{\circ}C$ was calculated as 2.78 vol%. It was possible to predict lower explosion limit by using the experimental flash point or flash point in the literature.

• 한국연소학회지
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• 제13권2호
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• pp.1-6
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• 2008

An experimental study of the flame response in a turbulent premixed combustor has been conducted with room temperature, atmospheric pressure inlet conditions using premixed natural gas. The fuel is premixed with the air upstream of a choked inlet to avoid equivalence ratio fluctuations. Therefore the observed flame response is only the result of the imposed velocity fluctuations, which are produced using a variable speed siren. Measurements are made of the velocity fluctuation in the nozzle using hot wire anemometry and of the heat release fluctuation in the combustor using chemiluminescence emission. The results are analyzed to determine the phase and gain of the flame transfer function as a function of the modulation frequency. Of particular interest is the effect of flame structure on the flame response predictions and measurements. The results show that both the gain and the phase of flame transfer function are closely associated with the flame length and structure, which is dependent upon the upstream flow perturbation as well as equivalence ratio in the current study.

• 한국자동차공학회논문집
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• 제19권5호
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• pp.45-50
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• 2011

Compression pressure of individual cylinder and valve timing have big influence on combustion pressure, indicated mean effective pressure (IMEP), emission, vibration, combustion noise and many other combustion parameters. Conventional method, however, to check compression pressure uniformity is done by mechanical pressure gage and valve timing is checked manually. This conventional method causes inaccuracy of cylinder pressure measurement because of different cranking speed results from battery status and temperature. Also to check valve timing, related FEAD parts should be disassembled and timing mark should be checked. This study describes and suggests new methodology to measure compression pressure by analysis of start motor current and to check valve timing by cylinder pressure with high accuracy. Results, it is found that detection of bulky as well as small leaky cylinder is possible by cranking motor current analysis and wrong valve timing can be detected by cylinder pressure analysis and cam and crank sensor signal.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3163-3168
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• 2008

Pulverized coal (PC) has become an important auxiliary fuel in the iron and steel industry since the technique of pulverized coal injection (PCI) system was developed for iron making. Combustion efficiencies of pulverized coal in blowpipes and tuyeres under various operational are numerically predicted to recognize the performance with the locations of nozzles in a blast furnace. A variety of parameters including the pulverized coal quantities, oxygen amounts, inlet temperature of the tuyeres and mass flow rate of coal carrier gas are taken into consideration. Also In order to develop more efficient than existing coal injection system, this study applies a flame measurement system using a charge couple device (CCD) camera and frame grabber. And it has used algorithms of auto sampling from flame shape information and composed the device for location control of PCI. This study find to further improve the blast furnace performance by the control of PCI locations.

• 대한기계학회논문집B
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• 제31권7호
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• pp.596-603
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• 2007

As increasing interest for soot emission. etc in combustion systems, various studies are being carried out for the reduction and measurement techniques of soot. Especially, laser induced incandescence is the useful measurement technique which has distinguished spatial and temporal resolution for primary particle size, volume fraction and aggregated particle size etc. Time resolved laser induced incandescence is the technique for measuring primary particle size that is decided to solve the signal decay rate which is related to the cooling behavior of heated particle by pulsed laser. The cooling behavior of heated particle is able to represent the heat and mass transfer model which are involved constants of soot property for surround gas temperature on the our previous work. In this study, it is applied to the time-dependence thermodynamic properties for soot temperature instead of constants of soot property for surround gas temperature and compared two different model results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.842-846
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• 2001

Our company produces boilers for industrial usages or power plants. The aim of this study is to investigate the flame structure, heat transfer to evaporator tube wall and NOx emission in the furnaces. Also we are to derive correct FEGT(Furnace Exit Gas Temperature) characteristic curve. When we design furnace and superheater, economizer etc. FEGT characteristic curve is very important factor for optimum design. We calculated turbulent reacting flow, heat transfer and NOx emission in furnace by using numerical modeling with the help of commercial code. Three dimensional steady state calculation is done. k-e turbulence model and equilibrium chemistry combustion model with $\beta-probability$ density function is used. To calculate radiation heat transfer discrete ordinates model is used. And we measured FEGT at several operating plants. Measurement is done by R-type thermocouple. Radiation shield is attached to the thermocouple to prevent radiation effect. Measured and calculated results show good agreement. And we could understand the flame structure and NOx formation positions in each furnaces.

• Journal of Acupuncture Research
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• 제21권3호
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• pp.193-214
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• 2004

Objective : The purpose of this study is to investigate the mechanism and effect of moxibustion with ginger objectively, to be used as the quantitative data through the measurement of temperature, and to grasp the thermodynamic characteristics of moxibustion with ginger. Methods : We have selected the indirect moxibustion with ginger among many indirect moxibustions. We produced a slice of ginger to a thickness of 3, 4, 5mm and the moxa cone having a diameter of 8mm, a height of 10mm for making a comparative study of characteristics of moxa cone according to change the density. We have made a comparative study of the thermodynamic characteristics of moxibustion with ginger with or without holes. We measured combustion times and calculated temperatures, temperature gradients in each period during a combustion of moxa. Results : 1. We found out it was not significantly influenced by the existence of the punched holes in a slice of ginger because the punched holes grow smaller immediately. 2. The duration of the preheating period became longer according to thickness of a slice of ginger and was not directly proportional to the density of moxa cone. The duration of the preheating period was extremely short when it burned a 100mg moxa cone. That was influenced by the density of moxa cone. 3. The duration of the heating period became longer according to thickness of a slice of ginger likewise the preheating period bacause the density of moxa cone had effected on the combustion characteristics. The duration of the heating period was extremely long when it burned a 100mg moxa cone. On the other hand the maximum temperature in the heating period was appeared that the combustion with a thin slice of ginger was highest and measured that the large density of moxa cone was higher. But the maximum temperature in the heating period was about $37.8^{\circ}C{\sim}44.2^{\circ}C$respectively lower in others. 4. The duration of the retaining period was some doubling shorter than that of the heating period that is concerned the shape of moxa cone. The temperature measured the close of a retaining period was $36.6^{\circ}C{\sim}41.8^{\circ}C$, that was considerably lower temperature. 5. The mean ascending temperature velocity and the mean descending temperature velocity were $0.042{\sim}0.073^{\circ}C/sec$, $-0.027{\sim}-0.064^{\circ}C/sec$ respectively. Then, the ascending temperature velocity was some faster than the ascending temperature velocity. Conclusions : The quantitative standard for obtaining the effective heating stimulation is that if the slice of ginger made a hole in it, we had to use the needle above 1.5mm diameter. The recommended size of a slice ginger is the 14mm diameter and the 2~3mm thickness. The moxa cone is formed the conical shape that the base diameter was 8mm, the height was 10mm, the density was $600mg/cm^2$.