• Journal of the Korean earth science society
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• v.29 no.1
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• pp.29-44
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• 2008

This study investigates the influence of the developing and decaying El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) on the relation between typhoon intensity and its formation. From the long-tenn data of 57 years ($1950{\sim}2006$), we first defined the developing El $Ni{\tilde{n}}o$ years and the neutral years. During the developing El Nino years, the typhoon intensity has a strong relationship with formation region of the tropical cyclone, which results in an increase of the accumulated cyclone energy and intensity of energy of typhoon. During the developing El $Ni{\tilde{n}}o$ year based on $Ni{\tilde{n}}o$ 3.4 SST, the locations for the formation of the category 4+5 typhoon move to the eastward region. The genesis potential function and the low-level cyclonic vorticity have an important role on the formation of strong tropical cyclones, which eventually develop as a typhoon class. In this study, the dynamic potential (DP) function (Gray, 1977) and EOF 1 and EOF 2 time series (RMM 1 and RMM 2) of real-time multivariate MJO (Wheeler and Hendon, 2004) are used to measure the genesis potential and the low-level cyclonic vorticity, respectively. To investigate the influence of the developing and decaying ENSO, we defined the Type I case of the decaying El $Ni{\tilde{n}}o$ that turnovers to La Nina, and the Type II case of the recovering years to the neutral condition. During the decaying El $Ni{\tilde{n}}o$ years as Type I, the locations of the strong DP, RMM 1 and RMM 2 move to the westward more prominently to induce retard of the strong typhoon developing.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.28-28
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• 2002

The hydrothermal reaction of Ni(NO₃)·6H₂O with 4.4'-oxybis(benzoic acid) (OBCH₂) and trans-1,2-bis(4-pyridyl)ethylene (bipyen) led to the formation of a 3-dimensional coordination polymer with the empirical formular of [Ni(OBC)(bipyen)]·H₂O. The complex has been characterized by X-ray diffraction, elemental analysis, TGA, IR, X-ray power diffraction (XRPD), It crystallized triclinic space group P1 with a = 9.280(2)Å., b = 11.317(4) Å, c = 12.442(3) Å, Z = 2, R (ωR₂) = 0.0346 (0.0846).

• Journal of the Korean Graphic Arts Communication Society
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• v.2 no.1
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• pp.71-75
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• 1984

NiNH$_{4}PO_{4}$ was Prepared from waste Ni catalyst used in hydrogenation of oil and fat, NiNH$_{4}PO_{4}$ was calcined at different temperature respectly 800, 1000, 1100$^{\circ}$C to prepare Nickel yellow. The results from this experiment are summerized as follow: 1) Nickel yellow formed at 1100$^{\circ}$C was most clearness yellow color from color analyzer data. 2) Nickel yellow was consist of ${\alpha}-Ni_{2}P_{2}O_{7}$, $Ni_{3}(PO_{4})_{2}$ from X-ray diffraction analysis. 3) The endothermic pick at 100$^{\circ}$C and exotherwic pick about 1050$^{\circ}$C on calcination of NiNH$_{4}PO_{4}$ were checked in DTA (difference thermal analysis data)

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.3
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• pp.143-150
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• 2016

In this study, we analyzed the relationship between rice yield and abnormal meteorological features for El $Ni{\tilde{n}}o$ years (with more than 1.0 Oceanic $Ni{\tilde{n}}o$ Index) since 1980 in South Korea. The national averaged rice yield of El $Ni{\tilde{n}}o$ years (n=14) was $4,663kg\;ha^{-1}$, which was less than that of non El $Ni{\tilde{n}}o$ years (n=16) by $102kg\;ha^{-1}$, but the difference was not significant statistically (t=1.215, p=0.234). The averaged rice yield of El $Ni{\tilde{n}}o$ end years ($4,558kg\;ha^{-1}$) was analyzed to be less than those of El $Ni{\tilde{n}}o$ start years and non El $Ni{\tilde{n}}o$ years by 209 and $206kg\;ha^{-1}$, respectively. But, the trend was not significant statistically (df=2, f=2.355, p=0.114). When meteorological anomalies were analyzed based on seasonal meteorological values, 18 meteorological events in total were observed for the past 30 years (1981-2010). In detail, abnormally much precipitation occurred 6 times, most often, followed by 5 times of abnormally low temperature during the past 30 years. Occurrence of meteorological anormalies of El $Ni{\tilde{n}}o$ end years was 0.71 events per year on average, which was higher than those of El $Ni{\tilde{n}}o$ start years ($0.43yr^{-1}$) and non El $Ni{\tilde{n}}o$ years ($0.63yr^{-1}$), even if the differences were not significant statistically (df=2, f=0.321, p=0.727).

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.466-470
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• 2008

The objective of this study is to convert methane into hydrogen using a nanoporous catalyst in the $CO_2$ containing syngas generated from the gasified waste. For the purpose, $Ni/Al_2O_3$ catalyst was prepared with the one-pot method. According to analyses of the catalyst, three dimensionally linked sponge shaped particles were created and the prepared nanoporous catalysts had larger surface area and smaller particle size and more uniform pores compared to the sphere shaped commercial catalyst. The catalyst for reforming reaction gave the highest $CH_4$ conversion of 91%, and $CO_2$ conversion of 92% when impregnated with 16 wt% of Ni at the reaction temperature of $750^{\circ}C$. At that time, the prepared catalyst remarkably improved the $CH_4$ and $CO_2$ conversion up to 20% compared to the commercial one.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.778-781
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• 1995

The mixed ferrite $Ni_{x}Co_{1-x}Fe_{2}O_{4}$ have been investigated by X-ray and $M\"{o}ssbauer$ spectoscpy. From the results of X-ray diffraction measurement the structure for this system is spinel, and the lattice constant is in accord with Vegard's law. $M\"{o}ssbauer$ spectra of $Ni_{x}Co_{1-x}Fe_{2}O_{4}$ have been taken at various temperature ranging from 13 to 800 K. The isomer shifts indicate that the valence states of the irons at both A(tetrahedral) and B(octahedral) sithe are found to be in ferric high-spin states. The variation of magnetic hyperfine fields at the A and B sites are explained on the basis on A-B and B-B supertransferred hyperfine interactions. It is found that Debye temperatures for the A and B sites of $CoFe_{2}O_{4}$ and $NiFe_{2}O_{4}$ are found to be ${\theta}_{A}=734{\pm}5K,\;{\theta}_{B}=248{\pm}5K,\;and\;{\theta}_{A}=378{\pm}5K,\;{\theta}_{B}=357{\pm}5K$, respectively. Atomic migration of $Ni_{0.3}Co_{0.7}Fe_{2}O_{4}$ starts near 450 K and increases rapidly with increasing temperature to such a degree that 61 % of the ferric ions at the A site have moved over to the B site by 700 K.

• Proceedings of the Korean Magnestics Society Conference
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• 2011.12a
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• pp.14-14
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• 2011

Limited understanding of the surface properties of $Pt_3Ni$ for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cell (PEMFC) has motivated the study of magnetic properties and electronic structures of Pt segregated $Pt_3Ni$ (111) surface during adsorption of oxygen molecule on it. The first principle method based on density functional theory (DFT) is carried out. Nonmagnetic Pt has induced magnetic moment due to strong hybridization between Ni 3d and Pt 5d. It is found that an oxygen molecule prefers bridge site with Pt rich subsurface environment for adsorption on the surface of Pt segregated $Pt_3Ni$ (111). It is seen that there is very small charge transfer from $O_2$ to Pt. The curve of energy versus magnetic moment of the oxygen explains the magnetic moments in transition states. We found the dissociation barrier of 1.07eV significantly higher than dissociation barrier 0.77eV on Pt (111) suggesting that the dissociation is more difficult on Pt segregated $Pt_3Ni$ (111) surface. The spin polarized densities of states are presented in order to understand electronic structures of Pt and $O_2$ during the adsorption in detail.

• Journal of the Korean Institute of Gas
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• v.5 no.4 s.16
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• pp.33-39
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• 2001

This paper was studied on corrosion behavior of absorption refrigeration systems using $LiBr-H_2O$ working fluids. In the various concentration of lithium bromide solution, polarization test of SS 400, Cu(C1220T-OL) and Al-Ni bronze is carried out. And the corrosion behavior of materials forming absorption refrigeration systems is investigated. The main results are as following: 1) As concentration of lithium bromide solution increases, polarization resistance of materials of each kinds is low. And open circuit potential becomes less noble, the corrosion current density is high drained 2) Open circuit potential of SS 400 is less noble than that of Cu and Al-Ni bronze, corrosion current density of SS5 400 is high drained than that of Cu and Al-Ni bronze. 3) Anodic polarization of Cu and Al-Ni bronze in $62\%$ LiBr solution continues the active state. that of Cu and Al-Ni bronze in the natural sea water maintains the active state and the critical current for passivation appears.

• Journal of Powder Materials
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• v.18 no.2
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• pp.122-128
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• 2011

This study investigated the high temperature oxidation behavior of Ni-22.4%Fe-22%Cr-6%Al (wt.%) porous metal. Two types of open porous metals with different pore sizes of 30 PPI and 40 PPI (pore per inch) were used. A 24-hour TGA test was conducted at three different temperatures of $900^{\circ}C$, $1000^{\circ}C$ and $1100^{\circ}C$. The results of the BET analysis revealed that the specific surface area increased as the pore size decreased from 30 PPI to 40 PPI. The oxidation resistance of porous metal decreased with decreasing pore size. As the temperature increased, the oxidation weight gain of the porous metal also increased. Porous metals mainly created oxides such as $Al_2O_3$, $Cr_2O_3$, $NiAl_2O_4$, and $NiCr_2O_4$. In the 40 PPI porous metal with small pore size and larger specific surface area, the depletion of stabilizing elements such as Al and Cr occurred more quickly during oxidation compared to the 30 PPI porous metal. Ni-Fe-Cr-Al porous metal's high-temperature oxidation micro-mechanism was also discussed.

• Journal of the Korean Applied Science and Technology
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• v.27 no.1
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• pp.29-36
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• 2010

The effects of La addition to Ni/$CeO_2$ methane partial oxidation catalysts were investigated. Catalysts were prepared by the impregnation and urea methods. In the preparation of catalysts, La content was changed from 1 wt% to 3wt%. Catalysts that contain 2wt% La showed the highest methane conversion of about 80% and CO selectivity of 84% and $H_2$ selectivity of 70%. This result may be stemmed from that, when La content is 2wt%, a fluorite oxide-type structure is well formed and carbon deposition is also decreased. Among the catalysts, 2.5wt% Ni/Ce(La)Ox showed the highest catalytic activity. From the experiment of changing reaction temperature with 2.5wt% Ni/Ce(La)Ox catalyst, it was found that the optimum reaction temperature is $750^{\circ}C$ and at this temperature methane conversion was about 90%, CO and $H_2$ selectivities were 94 and 80%, respectively.