• Journal of the Korean Society for Precision Engineering
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• v.12 no.7
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• pp.92-98
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• 1995

In the cluster tool, it is necessary to precisely control the vacuum pressure for the wafer transportation between transport module and cassette or process modules with the range of 1*10$^{-4}$ to 5*10$^{-5}$ torr. So we have designed the pressure control system for the transport module of the cluster tool and have evaluated its performance. Digital PID is utilized with the weighted sum of both three previous errors and one current error. The feedback signal is put into the nitrogen mass flow controller using the transport module controller. This pressure control system can prevent the transport module from the particle generation and backstreaming of hazardous process gases of the process chamber.

• International Journal of Precision Engineering and Manufacturing
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• v.5 no.1
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• pp.55-59
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• 2004

This study developed a fully automated test system for pressure vessels, containing such as oxygen, nitrogen, which is widely used in many industries. The pressure vessel test has three major parts including weight measurement test, water-hydraulic test and leakage test followed by cleaning and drying. The control system for these tests consists of three parts: a PLC, a monitoring system and a database management system. The PLC oversees overall control of test machines, while the monitoring system measures and displays weight, pressure, flow etc. for every situations, and the database management system stores test data. These three modules are designed to communicate with one another at 1 Hz frequency alerting problematic situations to the operator. The system has gone through actual field tests for verification of performances.

• Journal of Korean Physical Therapy Science
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• v.9 no.1
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• pp.159-166
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• 2002

The purpose of this study was to review the knowledge related to historic background, causes, symptoms, etiology and rehabilitation methods related to this disease and suggest some ways to reduce complications from it. The importance of underwater pressure disease was not emphasized, therefore, there is a need for continuous research on treatment methods and prevention for it. As one goes into the deeper water, they will be affected by the hydraulic pressure rather then the atmospheric pressure, and it will be increased 1mmHg by 10meters. Underwater pressure disease can be occurred when one comes out of deeper water too quicked. This results the imbalance of the composition rate of nitrogen in blood. However, there is not enough facilities to treat this disease and these facilities are located in limited areas. Therefore, there is an urgent need to set up a medial center that is specialized in prevention and treatment of underwater pressure disease.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2723-2728
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• 2008

The present study is numerically and experimentally performed to reveal the pumping characteristics of a helical-type molecular drag pump (HTDP) in the molecular transition flow region. In the experimental study, the pressures are measured simultaneously at the 5 positions along the helical channel of rotor under various conditions of outlet pressure and throughputs, and nitrogen is used as test gas. The outlet pressure is in the range of 26-533 Pa. As results, the local pressure changes are checked corresponding to the various outlet pressure and throughput of HTDP. In the numerical study, Navier-Stokes equations with slip boundary conditions are employed (Re< 1000, Kn< 0.1). The local pressure distribution and the pumping speed are calculated. The numerical results are compared with the experimental results. The numerically computed value agrees with the experimental data within an error of approximately 5%.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.53-58
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• 2008

Film cooling effectiveness on a flat plate was measured with pressure sensitive paint. The pressure sensitive paint(PSP) changes the intensity of its emissive light with pressure and the characteristic was used in film cooling effectiveness measurement. The film coolants were air and nitrogen, and by comparing the intensity of PSP coated surface with each coolant, the film cooling effectiveness was calculated. Three blowing ratio of 0.5, 1, and 2 were tested with two mainstream turbulence intensities. Results clearly showed the effect of blowing ratio and mainstream turbulence intensity. As the blowing ratio increases, the film cooling effectiveness was decreased near the film cooling holes. However, the film cooling effectiveness far downstream from the injection hole was higher for higher blowing ratio. As the mainstream turbulence intensity increased, the film cooling effectiveness was decreased at far downstream from the injection hole.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.569-572
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• 2006

In present study, the influence of changing combustor pressure on flame stabilization and nitrogen oxide (NOX) emission in the swirl flame with secondary fuel injection was investigated. The combustor pressure was controlled by suction at combustor exit. Pressure index ($P^*=Pabs/Patm$), where Pabs and Patm indicated the absolute pressure and atmosphere pressure, was controlled in the range of 0.7~1.15 for each equivalence ratio conditions. It could be observed that flame stable region became narrower with decreasing equivalence ratio and pressure index. In this combustion system, stable flames were formed until $P^*=\;0.7$. Emission index decreased with decreasing pressure index for overall equivalence ratio conditions and NOx reduction rates were almost identical for $P^*<1$ regardless of equivalence ratio though EINOx values showed different level with change of equivalence ratio for $P^*{\geq}1$. It is also observed that EINOx decreased with increasing secondary fuel injection ratio. Emission index of nitric oxide was controllable by adjusting the changing combustor pressure and injecting secondary fuel and this NOx reduction technology is applicable to industrial furnaces and air conditioning system.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.4
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• pp.281-288
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• 2001

The autoclave method and the traditional cooking method were compared for nutrients(especially, minerals), color difference, viscosity, reduction of sugar and amino nitrogen content of brown stock. The autoclave cooking method is better than the traditional cooking method for retaining protein and amino nitrogen contents, as well as for reducing sugar content. Also, reducing sugar content increased by the autoclave cooking method. Since the color of brown sauce was related with the reducing sugar content, the autoclave cooking method was more effective than the traditional cooking method for the color development of brown stock. Since the autoclave method can reduce the cooking time without a loss of quality in brown stock, the autoclave method is a viable alternative to the traditional method of preparing brown stock.

• Journal of Sensor Science and Technology
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• v.9 no.3
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• pp.248-255
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• 2000

Penning type sputtering system which has two opposed targets was implemented and the physical characteristics of the deposited carbon nitride films were investigated. When argon ratio was reduced and nitrogen ratio was increased in the sputtering gas mixture, Fe was less sputtered. The grain size of grown carbon nitride films was distributed from $150{\AA}$ to $250{\AA}$. As nitrogen partial pressure increases, growth rate and nitrogen incorporation in the film increases.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2320-2322
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• 1999

This paper was studied on the surface discharge characteristics and tracking phenomena on the solid insulator in liquid nitrogen ($LN_2$) at atmospheric pressure. In order to investigate the bubbles which have much influence on electric surface discharge in liquid nitrogen, Knife type electrode and plane electrode were arranged in different modes(Mode A, Mode B, and Mode C) and investigated for surface discharge and tracking phenomena. In Mode A, by the movement of bubbles tracking damage was formed under the electrodes. The tracking pattern in Mode B was formed along the electrode axis.

• Journal of the Korean Society of Combustion
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• v.13 no.1
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• pp.10-16
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• 2008

Numerical simulations of freely propagating premixed flames burning mixtures of methane and chlorinated hydrocarbons in fuel are performed at atmospheric pressure in order to understand the effect of chlorinated hydrocarbons on the formation of nitrogen oxide. A detailed chemical reaction mechanism is used, the adopted scheme involving 89 gas-phase species and 1017 elementary forward reaction steps. Chlorine atoms available from chlorinated hydrocarbons inhibit the formation of nitrogen oxides by lowering the concentration of radical species. The reduction of NO emission index calculated with thermal or prompt NO mechanism is not linear and is probably related to the saturation effect as $CH_3Cl$ addition is increased, In the formation or consumption of nitrogen oxide, the $NO_2$ and NOCl reactions play an important role in lean flames while the HNO reactions do in rich flames. The molar ratio of Cl to H in fuel has an effect on the magnitude of NO emission index.