• Korean Journal of Mathematics
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• 제28권1호
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• pp.1-7
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• 2020

A partition X describes that there exists α_i kinds of alleles occurring i loci for each i. All genes have multiple alleles, i.e., they exist in more than two allelic forms, although any one diploid organism can carry no more than two alleles. The number of possible genotypes in a multiple allel series depends on the number of alleles. We will deal with an n locus model in which mutation and gene conversion are taken into consideration. In this paper, we firstly find the probability p_n(x) of genotype $$p_{n+1}(x)=p_n(x){\sum\limits_{k=1}^{r}}q_{kx}p_n(k)$$ with the rates of mutation and gene conversion. Also we find the probability of genotype without the rates of mutation and gene conversion and we apply this probability to two examples.

• 공업화학
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• 제24권3호
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• pp.333-336
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• 2013

산업현장에서 배출되는 저온($150{\sim}250^{\circ}C$)의 배기가스에 포함된 질소산화물($NO_x$)을 제거하기 위한 공정으로써 산화 촉매와 암모니아 SCR 공정을 복합시킨 fast SCR 탈질공정에 대한 실험적인 연구가 수행되었다. Fast SCR 탈질공정을 위해서는 산화촉매를 이용 NO를 $NO_2$로 전환하는 것이 요구된다. 산화촉매 부피(Oxidation Catalyst Volume, OCV)에 따른 NO 전환율을 실험적으로 확인하였다. OCV 563000 h, 375000 h, 281000 h 각 경우에 NO 전환율은 37% : 45% : 51%이었다. 온도에 따른 fast SCR 탈질효율은 $NO_2/NO_x$ 비율 45%일 때 가장 높았다. $NO_2/NO_x$ 비율 45%, 온도 $200{\sim}250^{\circ}C$ 및 공간속도 $10000{\sim}30000h^{-1}$에서 standard SCR과 fast SCR 탈질효율을 비교한 결과, standard SCR은 공간속도 에 따라 온도별로 차이를 보였으나 fast SCR은 차이를 보이지 않았다. Fast SCR 반응을 고려한 탈질운전에서 공간속도 $10000h^{-1}$에서의 촉매부피와 비교하여 공간속도 $30000h^{-1}$으로 운전할 경우, NH3 SCR 촉매부피를 50% 이상 줄일 수 있음을 알 수 있었다.

• 한국대기환경학회지
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• 제8권1호
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• pp.58-67
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• 1992

For removing $NO_x$ and $SO_x$ from the flue gases emitted from stationary sources, $V_2O_5-MoO_3/TiO_2$ catalysts were prepared by the conventional impregnation method (aqueous solution) and a sort of surface fixation method(nonaqueous solution) as reported excellent reproducibility catalysts. And these catalysts observed their catalytic activities as well as their surface properties. V-Mo-O oxide, prepared from nonaqueous solution of $VOCl_3$ and $Mo(CO)_6$ and aqeous solution method, was supported as amorphous state by XRD and SEM measurements. The infrared spectra of fresh and used catalysts showed that in used catalysts, V=O bands decreased and new bands of vanadium oxysulfate bands were very sensitive. So the catalysts prepared from nonaqueous solution may bring about the high activity. Results from catalytic activity measurements at 350$^\circ$C, in the presence of $SO_2, NO$ conversion was more increased than in absence of $SO_2$. As the $MoO_3$ was added to $V_2O_5/TiO_2 system, SO_2$ conversion increased. It found that from the results, $V_2O-5-MoO_3/TiO_2$ catalysts prepared from an nonaqueous solution may bring about the high activity for both the reaction of NO and $SO_2$ removal.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.399-402
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• 2002

Industrial wastewater with high ammonium concentration was treated in batch biological systems which was a modified Ludzack- Ettinger process. Up to 78% conversion of $NH_4\;^+-N$ to $NO_x\;^--N$ was achieved in batch culture condition. Under anoxic condition with methanol as the carbon source, the denitrifiers decreased $NO_x\;^--N$ concentration from 608 mg/L to 5.6 mg/L in 22 d. As well as anoxic denitrification of $NO_x\;^-$ to $N_2$, dissimilatory nitrate reduction to ammonium also occurred under the condition as respiratory denitrification.

• 한국산학기술학회논문지
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• 제13권11호
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• pp.5610-5614
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• 2012

암모니아를 환원제로 사용하는 선택적촉매환원법(Selective Catalytic Reduction, SCR)에서 촉매의 다양한 공정조건에서의 질소산화물 전환특성을 조사하였다. $H_2$-TPR을 통해 Mn, Cu가 포함된 탈질촉매의 경우 저온에서의 산소사용능력으로 우수함을 확인할 수 있었다. 탈질촉매 #1의 경우 반응온도가 증가함에 따라 탈질효율이 감소하나 탈질촉매 #2의 경우 반응온도가 증가함에 따라 탈질효율이 증가하다가 일정하였다. 이러한 현상은 두 촉매의 $NH_3$ 산화능력의 차이에 의한 것이다.

• 한국자동차공학회논문집
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• 제23권2호
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• pp.169-177
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• 2015

In this study we investigated the regeneration methods for the lean $NO_x$ trap (LNT) catalyst in a 2.2L direct injection diesel engine. The regeneration methods were 1) in-cylinder post fuel injection and 2) external fuel injection strategy. The in-cylinder post fuel injection method uses in-cylinder injectors with the addition of the post fuel injection to supply enough reductants such as CO, $H_2$, THC. The external fuel injection method was enabled by installing a fuel injector with a wide spray angle before the LNT catalyst. Through the engine experiment, the $NO_x$ conversion efficiency, the amount of reductant exhaust gases, fuel consumption, and temperature behavior in the LNT catalyst were evaluated and compared for the two regeneration methods.

• 한국전기전자재료학회논문지
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• 제32권1호
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• pp.78-85
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• 2019

The effect of various lithium sources such as LiCl, LiOH, and Li-metal on the microstructure and electrochemical properties of granulated $SiO_x$ powders were investigated. Various lithium sources were metallurgically added for a passive pre-lithiation of $SiO_x$ to improve its low initial coulombic efficiency. In spite of using the same amount of Li in various sources, as well as the same process conditions, different lithium silicates were obtained. Moreover, irreversible phases were formed without reduction of $SiO_x$, which might be from additional oxygen incorporation during the process. Accordingly, there were no noticeable electrochemical enhancements. Nevertheless, the $Li_4SiO_4$ phase changes the initial electrochemical reaction, and consequently the relationship between the microstructure and electrochemical properties of metallurgically pre-lithiated $SiO_x$ could provide a guideline for the optimization of the performance of lithium ion batteries.

• 한국자동차공학회논문집
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• 제19권5호
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• pp.118-124
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• 2011

To reach the Euro-6 regulations of PM and $NO_x$ for light-duty diesel vehicles, it will be necessary to apply the CDPF and the de-$NO_x$ catalyst. The described system consists of a catalytic configuration, where the CDPF is placed downstream of the diesel engine and followed by a urea injection unit and a urea-SCR catalyst. One of the advantages of this system configuration is that, in this way, the SCR catalyst is protected from PM, and both white PM and deposits become reduced. In the urea-SCR system, the injection control of reductant is the most important thing in order to have good performance of $NO_x$ reduction. The ideal ratio of $NH_3$ molecules to $NO_x$ molecules is 1:1 based on $NH_3$ consumption and having $NH_3$ available for reaction of all of the exhaust $NO_x$. However, under the too low and too high temperature condition, the $NO_x$ reduction efficiency become slower, due to temperature window of SCR catalyst. And space velocity also affects to $NO_x$ conversion efficiency. In this paper, rig-tests were performed to evaluate the effects of $NO_x$ and $NH_3$ concentrations, gas temperature and space velocity on the $NO_x$ conversion efficiency of the urea-SCR system. And vehicle test was performed to verify control strategy of reductatnt injection. The developed control strategy of reductant injection was improved over all $NO_x$ reduction efficiency and $NH_3$ consumption in urea-SCR system. Results of this paper contribute to develop urea-SCR system for light-duty vehicles to meet Euro-5 emission regulations.

• 한국응용과학기술학회지
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• 제31권2호
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• pp.313-319
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• 2014

This study was performed to obtain high conversion efficiency of $NH_3$ and minimize generation of nitrogen oxides using metal-supported catalyst with Ag : Cu ratio. Through structural analysis of the prepared catalyst with Ag : Cu ratio ((10-x)Ag-xCu ($0{\leq}x{\leq}6$)), it was confirmed that the specific surface area was decrease with increasing metal content. A prepared catalysts showed Type II adsorption isotherms regardless of the ratio Ag : Cu of metal content, and crystalline phase of $Ag_2O$, CuO and $CuAl_2O$ was observed by XRD analysis. In the low temperature($150{\sim}200^{\circ}C$), a conversion efficiency of AC_10 recorded the highest(98%), whereas AC_5 (Ag : Cu = 5 : 5) also showed good conversion efficiency(93.8%). However, in the high temperature range, the amounts of by-products(NO, $NO_2$) formed with AC_5 was lower than that of AC_10. From these results, It is concluded that AC_5 is more environmentally and economically suitable.

• 한국응용과학기술학회지
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• 제31권1호
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• pp.159-166
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• 2014

In recent years, researchers have put a considerable effort to decrease the emission of harmful gaseous pollutants to the atmosphere. In order to remove simultaneously $SO_2$ and $NO_X$ from the flue gas of small and medium-sized ship, we designed minimal wet scrubber inside a compact multistage modular system. In this study we proceed experiment of elemental technology at each stage of the scrubber. The each stage is oxidation of NO which is the main component of $NO_X$, and removal of $SO_2$, respectively. $NaClO_2$ was used to oxidize NO gas, and NaOH was used to remove $SO_2$ gas. The maximum NO conversion efficiency and the $SO_2$ removal efficiency are both indicate 100%.