• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.473-478
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• 2008

In this experimental, selective catalytic reduction (SCR) of NO with NH3 over manganese sulfates and manganese sulfates was investigated with catalytic activity, kinetics, temperature programmed reduction (TPR) and TGA. Manganese oxides showed high catalytic activity for SCR at temperature below $200^{\circ}C$. In case of manganese sulfates, the temperature at which SCR of nitric oxide appears shifted to high temperature with sulfation degree, and the maximum catalytic efficiency decreased. The temperature of the onset of reduction for manganese oxides and manganese sulfates is about $160^{\circ}C$ and over $280^{\circ}C$, respectively. We suggest that the onset of reduction in TPR correlates with the onset of SCR activity. Because the pre-exponential factor of manganese sulfates is lower as 1/1000 times than that of other catalysts, catalytic activity of manganese sulfates for NO showed low. The reduction temperature of natural manganese ore which consists of various metal oxides showed lower than that of pure manganese oxides.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.5
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• pp.510-519
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• 2013

In this study, the spray characteristics of a pressure swirl atomizer classified into a liquid sheet-type swirl nozzle for Urea-SCR system were investigated experimentally with the variation of injection pressure. The length to diameter ratio ($l_o/d$) of the nozzle was 3.1, and the swirler was set inside the nozzle tip to give injecting fluid angular momentum. The injection duration of the nozzle was controlled by PWM (pulse width modulation) modes. The development processes of the spray were imaged by a 2-D PIV system, and the change of spray angle was measured. The atomization characteristics, including axial velocity and SMD, were measured using a 2-D PDA system with the injection pressures at room temperature and ambient pressure conditions. As the experimental results, the injection pressure had a significant impact on the spray structure showing a different shape around the spray leading edge, and the smaller SMD was observed with increasing injection pressures, which was similar to that of the previous work.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5610-5614
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• 2012

Performance of catalyst was studied with various operating conditions for selective catalytic reduction of $NO_x$ with $NH_3$. It is confirmed that catalysts containing Mn and Cu have a good efficiency in the usage of oxygen by the $H_2$-TPR analysis. In the case of catalyst #1, $NO_x$ conversion was decrease with the increase of reaction temperature. But in the case of catalyst #2, $NO_x$ conversion was increased and then remained constant with the increase of reaction temperature. This phenomenon is due to the difference of the $NH_3$ oxidation of both catalysts.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.4
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• pp.265-269
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• 2009

Formal specification plays important roles in guaranteeing software safety of safety-critical systems such as nuclear power plant's digital control systems. We had developed a technique [1] which synthesizes Function Block Diagram(FBD) programs from NuSCR formal requirements specifications, but it did not be used widely as it had no automatic tool support. FBD is one of the programming languages for Programmable Logic Controllers(PLC) based system. This paper introduces a CASE tool, NuSCRtoFBD, developed to automate the synthesis procedure. The CASE tool NuSCRtoFBD can reduce a number of errors occurred in the process of manual FBD programming.

• Journal of Institute of Convergence Technology
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• v.7 no.1
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• pp.15-18
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• 2017

As emission gas regulation of deisel vehicles is strengthened to Euro-6, It becomes difficult to deal with NOx regulated value mainly by EGR without additional after-treatment system. In addition, RDE(Real Driving Emissions) test will be introduced after september 2017. Therefore, It is essential to develop the after-treatment of diesel vehicles which reduce NOx emissions. It is possible to use DOC, DPF, LNT or DOC, DPF and SCR as a after-treatment system for reducing NOx. However, It is expected that the SCR will be applied widely because LNT alone does not have sufficient NOx purification efficiency. In this study, It tried to analyze the efficiency of reducing NOx emissions during the mode test by attaching a NOx sensor to test vehicle. As a result, It was confirmed that NOx emissions was significantly reduce through the after-treatment system from engine. And the NOx reduction efficiency of SCR was about 4.5 times better than DOC, DPF.

• Journal of IKEEE
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• v.23 no.1
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• pp.338-341
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• 2019

In this paper, we propose a novel ESD device with improved characteristics of LVTSCR, which is a representative ESD protection device, and verify the N-stack technology for design optimized for each required voltage of a specific application. The characteristics of the holding voltage and the trigger voltage, which are the main parameters, are examined and the temperature characteristic, which is an indicator of the tolerance characteristic, is also verified. well region and a parasitic NPN to form a series-connected structure. We used synopsys' T-cad simulation tool for characterization.

• Journal of the Korea Safety Management & Science
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• v.21 no.1
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• pp.17-23
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• 2019

The diesel engine generate many pollutants such as PM(Particulate matter) and NOx(Nitrogen oxide). So the SCR(Selective catalytic reduction) must be required to meet the emission standard. The SCR catalyst market is growing rapidly, and the automobile markets using alternative energy sources are growing rapidly. This study deals with optimization of the calcination process the manufacturing process of SCR catalyst to be competitive. The calcination process is a bottleneck and it is required to optimize productivity and accept to be safety, But we cannot trade off anything in terms of safety. We applied DOE(Design of experiments) among many research methods performed in various fields. In order to achieve quality and productivity optimization. The dependent variables in the DOE were selected as NO Conversion(%). The independent variables were selected as the calcination temperature, soaking time and fan speed RPM. the CCD(Central composite designs) constructs response surface using the data onto experience and finds optimum levels within the fitted response surfaces. Our tests are our stability guarantee and efficient together with operation.

• Journal of IKEEE
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• v.26 no.3
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• pp.520-523
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• 2022

In this paper, an ESD protection device with a simpler structure than the existing ESD protection device is proposed. The proposed new structure operates an additional NPN parasitic bipolar transistor by adding an N+ diffusion region and connecting it to the bridge region, thereby lowering the current gain. As a result, it was confirmed that the proposed ESD protection device has a trigger voltage of 10.8V and a holding voltage of 6.1V. It is expected to have reliability for 5V applications and is expected to have high tolerance characteristics.

• Journal of IKEEE
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• v.26 no.1
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• pp.119-123
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• 2022

This paper propose a new ESD protection device suitable for 12V class applications by adding a self-biasing structure to an ESD protection device with high holding voltage due to additional parasitic bipolar BJT. To verify the operating principle and electrical characteristics of the proposed device, current density simulation and HBM simulation were performed using Synopsys' TCAD Simulation, and the operation of the additional self-biasing structure was confirmed. As a result of the simulation, it was confirmed that the proposed ESD protection device has a higher level of holding voltage compared to the existing ESD protection device. It is expected to have high area efficiency due to the dual structure and sufficient latch-up immunity in 12V-class applications.

• Resources Recycling
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• v.22 no.1
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• pp.55-63
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• 2013

Considering considerable contents of vanadium and tungsten in spent SCR DeNOx catalysts, separation and recovery of those metals are required. In this respect, commercial anion exchange resin (MP600) was employed to recover vanadium from the synthetic solution of ammonium metavanadate. Experimental results indicated that vanadium exist as anion under the acidic condition (pH 2 ~ 6) and adsorbed on the resin. Although the adsorption rate was increased with temperature, the maximum amount of adsorption was not affected by temperature. Desorption took place under either strong acidic (less than pH 1) or strong caustic (higher than pH 13) condition. However, desorption seldom took place under moderate conditions (pH 3~11). Furthermore, adsorption equilibrium results agreed well with Freundlich isotherm and pseudo-second-order reactions. And, adsorption energy was evaluated using Dubinin-Radushkevich and Temkin isotherm.