• Journal of ILASS-Korea
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• v.22 no.2
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• pp.96-102
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• 2017

In order to reduce the NOx, SCR technology is most suitable. In this study, we focused on studying the injector part of urea-SCR system. When stoichiometric 1 mole of urea is injected, 2 moles of $NH_3$ are created. $NH_3$ causes a SCR reaction by reacting with NOx. However, urea is decomposed by the side reaction of coming out HNCO, deposit formation is formed. In this study, it was to design a nozzle that can spray the optimal spray flow rate. Test nozzle used in this experiment is efferverscent type. The result of the experiment, liquid flow rate was confirmed to be that they are dominated by the exit orifice diameter. The area ratio is defined by ratio of the area of exit orifice hole and that of aerorator. The droplet size was measured by varying the area ratios. In addition, it was also confirmed that there is no change of the liquid flow rate and air flow rate to change the aerorator at the same exit orifice. Further, It was confirmed that the droplet size was relatively uniform even though the area ratio was different. Finally, there is little change in the SMD that air flow rate increases in 0.3 or more ALR.

• Tribology and Lubricants
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• v.4 no.2
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• pp.36-43
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• 1988

Titanium carbide(TiC) and titanium nitride(TiN) flims were deposited on $Si_3N_4$-TiC composite cutting tools by chemical vapor deposition(CVD) using $TiCl_4-CH_4-H_2$ and $TiCl_4-H_2-N_2$ gas mixtures, respectively. The nonmetal to metal ratio of deposit increases with increasing $m_{C/Ti}$(mole ratio of CH$_4$ to TiCl$_4$ in the input) for TiC coatings and $m_{N/Ti}$(mole ratio of N$_2$ to TiCl$_4$ in the input) for TiN coatings. The nearly stoiahiometric films could be obtained under the deposition condition of $m_{C/Ti}$ between 1.15 and 1.61 for TiC, and that of $m_{N/Ti}$ between 25 and 28 for TiN. Also maximum microhardness of the coatings can be obtained in these ranges. The interfacial region of TiC coatings on $Si_3N_4$-TiC ceramics is wider than that of TiN coatings according to Auger depth profile analysis, which indicates good interfacial bonding for TiC. Experimental results show that TiC coatings have an randomly equiaxed structure and Columnar structure with(220) preferred orientation can be obtained for TiN coatings. And, multilayer coatings have a dense and equiaxed structure.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.1
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• pp.873-880
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• 2021

The purpose of this study is to investigate the impact of internal control on credit risk of joint stock commercial banks in Vietnam from 2007 to 2018. Furthermore, we specify bank-specific characteristics and macroeconomic conditions, and analyze how these factors affect credit risk of banks: the number of board members, the number of board members with banking or finance background as ratio of total board members, loans to total assets ratio, loans to deposit ratio, the number of days between the year-end and the publication of the financial statements, and the use of top four auditing firms proxy for five elements of internal control. By using the dataset of 30 Vietnamese joint stock commercial banks and Bayesian linear regression via Random-walk Metropolis Hastings algorithm, the results of this study show that five elements of internal control have a impact on bank credit risk, namely, control environment, risk assessment, control activities, information and communication, and monitoring activities. For factors of banks' characteristics, bank size and financial leverage have a negative impact on banks' credit risk, and bank age has a positive effect. For macroeconomic factors, inflation has a positive impact and economic growth has a negative impact on banks' credit risk.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.1
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• pp.751-758
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• 2021

This research is conducted to measure the efficiency level of Islamic banking in Indonesia and also to analyze the factors that can affect its efficiency level. This research used a purposive sampling technique to determine the sample size that will be used, with criteria that the bank has been operating since 2010 and consistently published its financial reports during the research period from 2011 until 2019; therefore, the total sample obtained was 11 samples. Analysis for efficiency level is done by using linear programming Stochastic Frontier Analysis (SFA), with test tool in the form of Frontier 4.1 and Eviews9 to find out what factors that affect efficiency. Efficiency test is done by involving input and output, while influence test used bank-specific variables comprising bank size, bank financial ratio, and macro-economy variable. Research result shows that there are only two banks that are almost close to being fully efficient firms, but the result still does not indicate that Islamic bank works efficiently. Results of the influence test show that factors affecting Islamic banking efficiency in Indonesia are bank size, Capital Adequacy Ratio (CAR), Non-Performing Finance (NPF), and Financing to Deposit Ratio (FDR), while other factors are not influential over the study period.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.253-263
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• 2002

To test for the effect of applied fertilizer and nutrients on uptake and transport for paddy rice, two paddy field trials were conducted with Dongjinbyeo in degenerated salt paddy field of Jeonbuk series from 1999 to 2000. After experiment, soil acidity, content of organic matter phosphate, silicate, potassium, calcium, and total nitrogen was increased by application of fresh cattle manure(FCM). Content of Nitrogen in soil layer leached inorganic nitrogen $NO_3$ was higher that that of $NH_4$ and was high in treatment of FCM. Content of $PO_4$ was higher in FCM than other treatments. But content of potassium was in high control. During the growth of rice plant, the amount of water consumption was 477mm. The amount of supplied nitrogen was high in treatment of no nitrogen(NN), 20% reduced application of LCU(LCU-20%), and no fertilizer. In case of phosphate, the supplied amount was more than the consumed amount with the exception of treatment "no phosphate(NP) and no fertilizer(NF)". In case of potassium, the consumed amount was more than the supplied amount in all treatments. The amount of applied nitrogen in the nutrient infiltrated water was high in treatment soil test(ST), C+FCM+Si(Silicate) and the ratio of recovered nitrogen was high in 20% reduced application of LCU. The amount of applied phosphate in the nutrient infiltrated water was high in FCM and that of applied potassium was high in 20% reduced application of LCU. Nitrogen use efficiency of paddy rice was high in 20% reduced application of LCU and use efficiency of phosphate and potassium was high in C+Si(Silicate). Grain yield of rice was high in order of 20% reduced application of LCU>C+Si=C+FCM+Si>C+FCM.

• Spatial Information Research
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• v.14 no.1 s.36
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• pp.129-150
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• 2006

Mineral potential mapping is an important procedure in mineral resource assessment. The purpose of this study is to analyze mineral potential using weight of evidence model and a Geographic Information System (GIS) environment to identify areas that have not been subjected to the same degree of exploration. For this, a variety of spatial geological data were compiled, evaluated and integrated to produce a map of potential mineral in the Gangreung area, Korea. for this, a spatial database considering mineral deposit, topographic, geologic, geophysical and geochemical data was constructed for the study area using a GIS. The used mineral deposits were non-metallic(Kaolin, Porcelainstone, Silicastone, Mica, Nephrite, Limestone and Pyrophyllite) deposits of sedimentary type. The factors relating to mineral deposits were the geological data such as lithology and fault structure, geochemical data, including the abundance of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Si, Sr, V, Zn, $Cl^-,\;F^-,\;{PO_4}^{3-},\;{NO_2}^-,\;{NO_3}^-,\;SO_{42-}$, Eh, PH and conductivity and geophysical data, including the Bouguer and magnetic anomalies. These factors were used with weight of evidence model to analyze mineral potential. Probability models using the weight of evidence were applied to extract the relationship between mineral deposits and related factors, and the ratio were calculated. Then the potential indices were calculated by summation of the likelihood ratio and mineral potential maps were constructed from Geographic Information System (GIS). The mineral potential maps were then verified by comparison with the known mineral deposit areas. The result showed the 85.66% in prediction accuracy.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.188-191
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• 2008

There have been many methods for producing natural gas from gas hydrate reservoirs in permafrost and sea floor sediments. It is well knownthat the depressurization should be a best option for Class 1 gas hydrate deposit, which is composed of tow layers: hydrate bearing layer and an underlying free gas. However many of gas hydrate reservoirs in sea floor sediments are classified as Class 2 that is composed of gas hydrate layer and mobile water, and Class 3 that is a single gas hydrate layer. The most appropriate production methods among the present methods such as thermal stimulation, inhibitor injection, and controlled oxidation are still under development with considering the gas hydrate reservoir characteristics. In East Sea of Korea, it is presumed that the thick fractured shale deposits could be Class 2 or 3, which is similar to the gas hydrate discovered offshore India. Therefore it is needed to evaluate the possible production methods for economic production of natural gas from gas hydrate reservoir. Here we would like to present the production of natural gas from gas hydrate deposit in East Sea with industrial flue gases from steel company, refineries, and other sources. The existing industrial complex in Gyeongbuk province is not far from gas hydrate reservoir of East Sea, thus the carbon dioxide in flue gas could be used to replace methane in gas hydrate. This approach is attractive due to the suggestion of natural gas productionby use of industrial flue gas, which contribute to the reduction of carbon dioxide emission in industrial complex. As a feasibility study, we did the NMR experiments to study the replacement reaction of carbon dioxide with methane in gas hydrate cages. The in-situ NMR measurement suggeststhat 42% of methane in hydrate cages have been replaced by carbon dioxide and nitrogen in preliminary test. Further studies are presented to evaluate the replacement ratio of methane hydrate at corresponding flue gas concentration.

• Journal of ILASS-Korea
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• v.8 no.2
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• pp.1-6
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• 2003

The liquid phase LPG injection (LPLI) system (the third generation technology) has been considered as one of the next generation fuel supply systems for LPG vehicles, since it has a very strong potential to accomplish the higher power, higher efficiency, and lower emission characteristics than the mixer type(the second generation technology) fuel supply system However. when a liquid LPG fuel is injected into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. This leads to freezing of the moisture in the air around the outlet of a nozzle, which is called icing phenomenon. It may cause damage to the outlet nozzle of an injector or inlet valve seat. In this work, the experimental investigation of the icing phenomenon was carried out The results showed that the icing phenomenon and process were mainly affected by humidity of inlet air instead of air temperature in the inlet duel. Also, it was observed that the total ice formed around the nozzle weighs at about $150mg{\sim}260mg$ after injection for ten minutes. And some fuel species were found in the ice attached at the front side of a nozzle, while frozen ice attached at the back of a nozzle was mostly' consisted of moisture of inlet air. Therefore, some frozen ice deposit. detached from front nozzle of an injector, may cause a problem of unfavorable air fuel ratio control in the small LPLI engine.

• Journal of the Mineralogical Society of Korea
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• v.18 no.3 s.45
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• pp.227-236
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• 2005

Hydrothermal tourmaline occurs as aggregates or dissemination in the diaspore nodule from an aluminum-rich clay deposit, Milyang, southeastern Korea. Most crystals of tourmaline show complex textures that are finely zoned. The fine-scale chemical zonation of hydrothermal tourmaline reflects the fluctuation conditions that would be expected from fluid mixing in open systems. Oscillatory chemical zoning in tourmaline formed and showed similar patterns, regardless of its crystallographic directions. Mg was enriched in the early stage of crystal growth while Fe was enriched in the later stage, with fluctuations of the ratio of Fe to Mg. Chemical analysis, BSE images, and X-ray compositional maps confirm that the oscillatory Boning in tourmaline is exclusively controlled by the variations of Fe and Mg contents, but the contribution of boron to the zonation is insignificant. The fact that tourmaline altered to diaspore and dickite indicates that tourmaline was unstable with respect to these aluminous minerals as the B, Fe, and Mg activities decreased. Therefore, the aluminum activity may control the stability of tourmaline in the hydrothermal system.

• Geotechnical Engineering
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• v.8 no.2
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• pp.31-44
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• 1992

The probabilistic and statistical model is used to estimate the probability of liquefaction potential and pore water pressure build up due to earthquake in fully saturated sand deposit for each case of being structure(anisotropic) or not(isotropic). To execute this paper, dynamic shear strength parameters to show the relationship between shear strength and cyclic loading under isotropic or anisotropic condition in saturated sand deposit are presented. Using these parameters, the program which Predicts Pore water Pressure build up due to earthquake is developed. Using the 3-dimensional Random Field Model considering uncertainty of resistance and strength parameter, the program which computes the probability of liquefaction potential is developed. The developed program is applied to a case study, and then the result shows that the probability of liquefaction in isotropic condition is higher than in anisotropic condition. The ratio of pore water pressure tends to decrease as Kc increases.