• 한국연소학회:학술대회논문집
• /
• 대한연소학회 2003년도 제27회 KOSCO SYMPOSIUM 논문집
• /
• pp.89-94
• /
• 2003

For the development of high efficiency and low emission combustion systems, high temperature air combustion technology has been tested by utilizing preheated air over 1100 K and exhaust gas recirculation. In this system, combustion air is diluted with large amount of exhaust gases ($N_2$, $CO_2$), such that the oxygen concentration is relatively low in the reaction zone, leading to low flame temperature. Since, the temperature fluctuations and sound emissions form the flame are small and flame luminosity is low, the combustion mode is expected to be flameless or mild combustion. Experiment was performed to investigate the turbulent flame structure and $NO_X$ emission characteristics in the high temperature air combustion focused on coflowing jet diffusion flames which has a fundamental structure of many practical combustion systems. The effect of turbulence has also been evaluated by installing perforated plate in the oxidizer inlet nozzle. LPG was used as a fuel. Results showed that even though $NO_X$ emission is sensitive to the combustion air temperature, the present high temperature air combustion system produce low $NO_X$ emission because it is operated in low oxygen concentration condition in excess of dilution.

• 한국반도체및디스플레이장비학회:학술대회논문집
• /
• 한국반도체및디스플레이장비학회 2005년도 춘계 학술대회
• /
• pp.139-145
• /
• 2005

In the study, in order to deposit TaN thin film using diffusion barrier and bottom electrode we made the Plasma Assisted ALD equipment and confirmed the electrical characteristic of TaN thin films deposited PAALD method, PAALD equipment depositing TaN thin film using PEMAT(pentakis(ethylmethlyamlno) tantalum) Precursor and $NH_3$ reaction gas is aware that TaN thin film deposited of high density and amorphous phase with XRD measurement The degree of diffusion and react ion taking place in Cu/TaN(deposited using 150 W PAALD)/$SiO_2$/Si systems with increasing annealing temperature was estimated from MOS capacitor property and the $SiO_2(600\;\AA)$/Si system surface analysis by C-V measurement and secondary ion material spectrometer(SIMS) after Cu/TaN/$SiO_2(400\;\AA)$ system etching. TaN thin film deposited PAALD method diffusion barrier have a good diffusion barrier property up to $500^{\circ}C$.

• 반도체디스플레이기술학회지
• /
• 제18권1호
• /
• pp.65-69
• /
• 2019

The cure properties of ethoxysilyl diglycidyl isocyanurate(Ethoxysilyl-DGIC) and ethylsilyl diglycidyl isocyanurate (Ethylsilyl-DGIC) epoxy resin systems with a phenol novolac hardener were investigated for anticipating fan out-wafer level package(FO-WLP) applications, comparing with ethoxysilyl diglycidyl ether of bisphenol-A(Ethoxysilyl-DGEBA) epoxy resin systems. The cure kinetics of these systems were analyzed by differential scanning calorimetry with an isothermal approach, and the kinetic parameters of all systems were reported in generalized kinetic equations with diffusion effects. The isocyanurate type epoxy resin systems represented the higher cure conversion rates comparing with bisphenol-A type epoxy resin systems. The Ethoxysilyl-DGIC epoxy resin system showed the highest cure conversion rates than Ethylsilyl-DGIC and Ethoxysilyl-DGEBA epoxy resin systems. It can be figured out by kinetic parameter analysis that the highest conversion rates of Ethoxysilyl-DGIC epoxy resin system are caused by higher collision frequency factor. However, the cure conversion rate increases of the Ethylsilyl-DGEBA comparing with Ethoxysilyl-DGEBA are due to the lower activation energy of Ethylsilyl-DGIC. These higher cure conversion rates in the isocyanurate type epoxy resin systems could be explained by the improvements of reaction molecule movements according to the compact structure of isocyanurate epoxy resin.

• 한국세라믹학회지
• /
• 제35권5호
• /
• pp.505-511
• /
• 1998

단결정 Si 기판 위에 증착한 Co/Hf과 Co/Nb 이중층으로부터 형성된 Co 실리사이드의 성장기구에 대하여 조사하였다. 두 경우 모두 500$^{\circ}C$ 이상에서 CoSi2가 주로 형성되었으나 그 결정방위의 성장양상은 서로 달랐다. Co/Hf/(100)Si 구조에서는 Si 기판과 에피텍셜 관계를 갖는 결정립과 그렇지 않은 결정립이 서로 혼합되어 성장하였다. 그러나 Co/Nb/(100)Si에서는 처음부터 에피텍셜 관계를 갖지 않는 결정립들만이 형성되었다. 동일한 구조임에도 불구하고 이렇게 내열금속 중간층에 따라 성장된 실리사이드의 결정방위가 달라지는 것으 안정한 반응제어층의 형성 및 고온에서의 그 분해과정과 관련이 있었다. 여러 구성원소들로 이루어진 반응제어층이 고온까지 안정할 경우에는 Co의 확산이동을 균일하게 제어하여 실리사이드의 에피텍셜 성장이 가능하다.

• 한국분무공학회지
• /
• 제3권4호
• /
• pp.43-49
• /
• 1998

In order to clarify the effect of equivalence ratio and kinds of fule in flame structure, a numerical simulation of triple flame developed in a co-flowing methane-air and air stream was carried out by the elementary chemical reaction mechanism. The following conclusions were obtained. Equivalence ratio at which the apparent burning velocity is maximum is a little larger than that of the one-dimensional premixed flame. Apparent burning velocities are two times higher than that of the one-dimensional premixed flame for the methane-air. The flame thrusts out forward in the downstream of the boundary between mixture and air stream, and a part of the flow is bent and forks out in this protruding flame so that a triple flame is originated; this triple flame is composed of fuel rich and lean premixed flame branches and a diffusion flame branch. Near the equivalence ratio at which the burning velocity of rule-dimensional premixed flame is the largest the effect of one-dimensional premixed flame becomes large and the fuel rich premixed flame advances and becomes vertical to the flow direction.

• 산업기술연구
• /
• 제20권A호
• /
• pp.73-82
• /
• 2000

This study was implemented to find an optimal model for wastewater treatment processes using PHOENICS(Parabolic, hyperbolic or Elliptic Numerical Integration Code Series) and ASM(Activated Sludge Model). PHOENICS is a general software based upon the laws of physics and chemistry which govern the motion of fluids, the stresses and strains in solids, heat flow, diffusion, and chemical reaction. The wastewater flow and removal efficiency of particle in two phase system of a grit chamber in wastewater treatment plant were analyzed to inquire the predictive aspect of the operational model. ASM was developed for a biokinetic model based upon material balance in complex activated sludge systems, which can demonstrate dynamic and spatial behavior of biological treatment system. This model was applied to aeration tank and settling chamber in Choonchun city, and the modeling result shows dynamic transport in aeration tank. PHOENCS and ASM could be contributed for the optimal operation of wastewater treatment plant.

• Kyungpook Mathematical Journal
• /
• 제60권2호
• /
• pp.335-347
• /
• 2020

In this paper, we take into account a parasite-host system with reaction-diffusion. Firstly, we derive conditions for Hopf, Turing, and wave bifurcations of the system in the spatial domain by means of linear stability and bifurcation analysis. Secondly, we display numerical simulations in order to investigate Turing pattern formation. In fact, the numerical simulation discloses that typical Turing patterns, such as spotted, spot-stripelike mixtures and stripelike patterns, can be formed. In this study, we show that typical Turing patterns, which are well known in predator-prey systems ([7, 18, 25]), can be observed in a parasite-host system as well.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
• /
• pp.207-212
• /
• 1994

A mathematical model is developed for a batch reactor in which the free radical bulk copolymerization of styrene and acrylonitrile takes place. In this model, we introduce the free volume theory to quantify the diffusion controlled termination and propagation reactions, and develop a model for the chain length dependent termination reaction in the context of the pseudo kinetic rate constant method(PKRCM). The simulation results from this model are found to be in good agreement with experimental data under different copolymerization conditions. The present model can predict both the copolymer composition and the number and weight average molecular weights. These kinetic approaches provide greater insight into the performance of the batch reactor used for the free radical bulk copolymerization of styrene and acrylonitirle.

• 한국결정성장학회:학술대회논문집
• /
• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
• /
• pp.121-125
• /
• 1998

Langasite is a new piezoelectric material which is similar to quartz in its acoustic behaviours. In this study, pure Langasite and Langasite family grouo powders were synthesized by the solid state reaction in air. And then diffusion of synthesized powders were controlled by B and C ions in the{{{{ { A}_{ 3} { B}_{5} { CD}_{ 14 }}}}} structure. Dielectric constant and lattice anisotripy of Langasite and family group were measured to be 17, 22~27 in the range of 1 kHz to 13 MHz and about 1.6. respectively.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
• /
• pp.100-105
• /
• 1992

A mathematical model is developed for a CSTR in which free radical solution polymerization of methyl methacrylate(MMA) takes place. It turns out that five ordinary differential equations are to be treated simultaneously in order to predict the reactor performance. Although the reaction proceeds under the conditions of relatively low temperature and pressure, the system shows very complex bifurcation features due to the diffusion limitation (gel effect) and the temperature dependence of the kinetic parameters and physical properties. The effects of various system parameters on the reactor performance as well as on the polymer properties are investigated by using the bifurcation analysis. The application of the singularity theory enables us to divide the parameter space into several different regions, in each of which the system takes a unique steady state structure. Under certain circumstances, complex dynamic features such as HB points and limit cycles are observed and these should be taken into consideration in the reactor design.