• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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• pp.73-82
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• 2001

The characteristics of the catalytically supported thermal combustion with Pd-based catalyst using the bench scale high pressure combustor has been investigated up to 7 atm. The emission of $NO_{\chi}$ depends on the preheating temperature and the excess air ratio. Most $NO_{\chi}$ emission seems to come from the pre-burner for the preheating of the inlet gas. Decreasing excess air ratio in the inlet gas below 1.5 results in the stable catalytically supported thermal combustion in the post combustion region while the $NO_{\chi}$ emission increased up to 15 ppm. Further, the increase of the pressure shows the dramatic increase of the emission CO and THC. However, the $NO_{\chi}$ emission decreased slightly due to the lower combustion temperature at the high pressure.

• Corrosion Science and Technology
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• 제14권6호
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• pp.253-260
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• 2015

The pitting behaviours of 304L and 316L stainless steels were investigated at $3^{\circ}C$ to $90^{\circ}C$ in 1 M solutions of NaCl, NaBr and NaI by potentiodynamic polarization. The temperature dependences of the pitting potential varied according to the anion, being near linear in bromide but exponential in chloride. As a result, at low temperatures grades 304L and 316L steel are most susceptible to pitting by bromide ions, while at high temperatures both stainless steels were more susceptible to pitting by small chloride anions than the larger bromide and iodide. Thus, increasing temperature appears to favour attack by smaller anions. This paper will attempt to rationalise both of the above findings in terms of the point defect model. Initial findings are that qualitatively this approach can be reasonably successful, but not at the quantitative level, possibly due to insufficient data on the mechanical properties of thin passive films.

• Corrosion Science and Technology
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• 제14권4호
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• pp.184-189
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• 2015

In this study, the combined effect of chloride and thiosulfate ions and the effect of the ratio of the two ions on passivation in 304L, 316L, and the duplex stainless steels 2101 and 2205 are investigated using potentiostatic scratch tests. Cyclic polarization and the scratch tests were used to understand the role of anions on localized corrosion in these systems. It was found that the thiosulfate pitting began at a lower potential for 2101 than 304L in 0.6 M NaCl + 0.03 M $Na_2S_2O_3$ solution. The pit morphologies for 304L, 316L, and 2101 in an 0.6 M NaCl + 0.03 M $Na_2S_2O_3$ solution were very different from each other. The results indicate that the pitting switches from predominately thiosulfate pitting to chloride pitting at approximately 0.1 V.

• Corrosion Science and Technology
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• 제14권4호
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• pp.195-199
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• 2015

Materials of choice for offshore structures and the marine industry have been increasingly favoring materials that offer high strength-to-weight ratios. One of the most promising families of light-weight materials is titanium alloys, but these do have two potential Achilles' heels: (i) the passive film may not form or may be unstable in low oxygen environments, leading to rapid corrosion; and (ii) titanium is a strong hydride former, making it vulnerable to hydrogen embrittlement (cracking) at high temperatures in low oxygen environments. Unfortunately, such environments exist at deep sea well-heads; temperatures can exceed $120^{\circ}C$, and oxygen levels can drop below 1 ppm. The present study demonstrates the results of investigations into the corrosion behavior of a range of titanium alloys, including newly developed alloys containing rare earth additions for refined microstructure and added strength, in artificial seawater over the temperature range of $25^{\circ}C$ to $200^{\circ}C$. Tests include potentiodynamic polarization, crevice corrosion, and U-bend stress corrosion cracking.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2006년도 추계 학술발표회 발표논문집
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• pp.385-389
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• 2006

다중주파수 초음파를 이용한 하수슬러지의 전처리시 탈수성와 침강성에 관한 실험을 실시하여 다음과 같은 결론을 얻었다. 1. CST 변화량은 조사시간 80분까지 증가하다가 이후에는 감소하는 경향을 보여 탈수성이 개선될 수 있음을 보였다. 또한 삼중주파수가 이중주파수 일때보다 더 큰 영향을 끼쳤다. 2. $SV_{30}$의 변화량은 초음파 조사와 동시에 급격히 변화하여 침강성의 악화를 가져왔다. 또한 삼중주파수가 이중주파수 일때보다 침강속도를 더 빨리 악화시켰다. 3. 수온은 상승하였고, pH의 변화는 거의 일어나지 않았다. 본 실험에서 다중주파수를 사용하였을때, 단일주파수를 사용했을때보다 효율이 높았다. 그러나 다중주파수를 이용한 초음파 처리시 정확한 탈수성과 침강성 평가를 위해 ECP, 여과비저항(SRF), 입도분도, 점도 등 다양한 후속연구를 진행해야 할 것이다.

• Corrosion Science and Technology
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• 제9권4호
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• pp.159-163
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• 2010

Precise coating weight control is very important issue on quality and minimizing operating costs on continuous galvanizing line. These days, many steel making companies are having a new understanding of cost importance by rise raw material prices and customer's requirement for cost reduction. Dongbu steel also meets these situations and decided to develop the technologies. Dongbu Steel developed Integrated coating weight control system jointly with Objective Control Ltd. and installed 2CGL and 4CGL. Several technological functions were developed and realized to achieve true hands-off operation and maximum cost benefit by combining model-based preset and dynamic prediction models. We also installed it on 1 CGL on April, 2008. This paper will present the interface, functions and application result of the integrated coating weight control system including Zn saving and coating weight uniformity.

• Corrosion Science and Technology
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• 제11권6호
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• pp.247-256
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• 2012

Harmonic current was measured for a dummy cell with various values of resistance, and the procedure developed through the measurements was applied to the investigation of effects of the amplitude of applied frequency and applied potential on the harmonic current of a stainless steel and a carbon steel in chloride containing solutions. From the measurements of harmonic current in the dummy cell, the optimum values of applied frequency and applied potential in harmonic current measurements were found to be 1 mHz and 20 mV (or lower), respectively. Increase in harmonic current with applied frequency was observed in the case where the level of harmonic current is low as in a stainless steel. Decrease in polarization resistance was also noted in this corrosion system with either increasing applied frequency or decreasing applied potential. However, no obvious effects of applied frequency was observed on harmonic current and polarization resistance in a carbon steel in which the level of harmonic current is high.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.318-321
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• 2000

This paper propose the method of constructing the highly efficiency adder and multiplier systems over finite fie2, degree of uk terms, therefore we decrease k into m-1 degree using irreducible primitive polynomial. We propose two method of control signal generation for perform above decrease process. One method is the combinational logic expression and the other method is universal signal generation. The proposed method of constructing the highly adder/multiplier systems is as following. First of all, we obtain algorithms for addition and multiplication arithmetic operation based on the mathematical properties over finite fields, next we construct basic cell of A-cell and M-cell using T-gate and modP cyclic gate. Finally we construct adder module and multiplier module over finite fields after synthesize ${\alpha}$$\^$k/ generation module and control signal CSt generation module with A-cell and M-cell. Then, we propose the future research and prospects.

• Corrosion Science and Technology
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• 제15권6호
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• pp.320-325
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• 2016

To perform ultrasonic testing (UT) thickness measurement of the secondary side piping installed in nuclear power plants, the insulation for preventing heat loss should be removed. The type of insulation can be divided into fixed and removable insulation. Fixed and removable insulation have their own strengths and weaknesses. Removable insulation has been installed in the components susceptible to wall thinning caused by FAC and erosion from Shin-Kori unit 1, which commenced its commercial operation in 2011. In this paper, the number of repeated inspections of components and the number of replacements of fixed insulation were estimated and a more economical way was identified based on the manufacturing and installation costs for fixed and removable insulation.

• Corrosion Science and Technology
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• 제10권5호
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• pp.162-166
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• 2011

Effects of chemical compositions and manufacturing conditions on mechanical properties and microstructures were investigated in order to obtain galvannealed high strength dual phase steel sheets with superior mechanical properties and coating properties. An intercritical annealing between Ac1 and Ac3 was conducted to produce the DP (dual phase) steel sheets, followed by quenching to room temperature. The purposes of Al addition are to reduce the iron oxidation with chemical composition (Si, Mn etc.) and to improve the wettability by liquid zinc. The present study will focus on the characterization for making dual phase steel sheets and enhancing the galvanizability of Al added DP steel sheets about continuous annealing line in CGL.