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Search Results: 1 - 10 of 251791 matches for " T. K. Kim "
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Analysis of Dynamic Cross Response between Spindles in a Dual Spindle Type Multi-Functional Turning Machine  [PDF]
Y. H. Choi, S. T. Kim, T. Y. Seo, K. H. Kim
Journal of Power and Energy Engineering (JPEE) , 2013, DOI: 10.4236/jpee.2013.17004
Abstract:

In order to meet increasing demand for higher productivity and flexibility, recently many kinds of multi-functional machine tools, which are capable of multiple machining functions or different kinds of machining processes on one machine, have been developed and widely used in manufacturing industries. In this study, a multi-functional turning lathe, which has two spindles and two turrets so that multiple turning operations and various machining processes could be performed simultaneously, has been developed. Furthermore, the equations of correlation between whole responses and cross responses of the two spindles have been derived to examine to what extent the two spindles affect each other’s vibrations.

Evaluation of Accuracy and Precision of IRMS by Using Standard Materials and Applications  [PDF]
J. Y. Hwang, B. K. Kim, M. S. Kim, J. W. Choi, T. S. Kim, W. S. Lee
Journal of Agricultural Chemistry and Environment (JACEN) , 2016, DOI: 10.4236/jacen.2016.54022
Abstract: The isotope ratio mass spectrometer (IRMS) is an instrument that measures both of the elemental contents and isotope ratios of hydrogen, oxygen, carbon, nitrogen and sulfur in environmental samples at the same time. In this study, we want to try to get two main goals; first, to make up for setting the analytical conditions such as accuracy and precision, second, to apply for comparing of the carbon and nitrogen isotope ratio of sediments in the abandoned mine located in middle province of Korea. For the first goal, a recently introduced IRMS was used to analyze CRM (certified reference materials), which helped to make up the analytical conditions of carbon and nitrogen isotope ratios. So, the accuracy and precision of isotope ratios and elemental contents were also assessed simultaneously, and also the results were very satisfactory. The analytical results of carbon reference materials (EMA-P2) showed an accuracy of -2.801 × 10‰ ± 0.01‰ (2σ) and a precision of 0.009‰ in the mass range from 0.008 μg - 0.162 μg. For nitrogen reference materials (EMA-P2), an accuracy of -1.632‰ ± 0.72‰ (2σ) was obtained in the mass range from 0.082 - 0.162 mg. These values of accuracy and precision are higher than those reported by other studies. For the second goal, carbon and nitrogen isotopes in river sediment near abandoned mines were analyzed based on the established analytical conditions. The result suggested that carbon isotope ratios ranged from -22.5‰ - -7.5‰ and nitrogen isotope ratios from -1.9‰ - 7.9‰. By comparing the isotope ratios and sampling sites of sediment, we know that the nitrogen isotope values in samples of entrance area of mine are greater than those of the farm house area, which is indicating the effects of organic materials. So, we could guess that the newly accumulated organic materials were much more in the farm house area than mine entrance area. And a result of this study, the accuracy and precision tests of IRMS using certified reference materials were very satisfactory and optimum analytical conditions were established well. And also, it was found that the applications of isotopic analysis for environmental samples by using the IRMS could be very useful for the studies on tracing pollution sources.
Alon-Babai-Suzuki's Conjecture Related to Binary Codes in Nonmodular Version
Hwang K-W,Kim T,Jang LC,Kim P
Journal of Inequalities and Applications , 2010,
Abstract: Let and be sets of nonnegative integers. Let be a family of subsets of with for each and for any . Every subset of can be represented by a binary code a such that if and if . Alon et al. made a conjecture in 1991 in modular version. We prove Alon-Babai-Sukuki's Conjecture in nonmodular version. For any and with , .
Comparison of H5N1, H5N8, and H3N2 Using Decision Tree and Apriori Algorithm  [PDF]
S. P. Jang, K. H. Park, Y. L. Kim, H. N. Cho, T. S. Yoon
Journal of Biosciences and Medicines (JBM) , 2015, DOI: 10.4236/jbm.2015.36008
Abstract:

H3N2, H5N1 and H5N8 virus were wide-spread epidemic in South Korea. Especially in 2014 Korea, the serious outbreak of avian influenza caused by H5N8 took place, effecting not only birds but also dogs. Antibody of H5N8 virus was found on a dog which differentiated the virus from existing H3N2 canine virus. At this point, we wanted to find out why H5N8 was self-medicated in dogs and whether H5N8 would cross species boundaries and be fatal to dogs or other species. While H5N1 is avian influenza like H5N8, many cases of fatal infections among dogs caused by H5N1 have been reported. Another kind of avian influenza, H3N2 is most common type of canine influenza in Asia. With the use of decision tree and apriori algorithm, we could find out characteristics of H5N8 by comparing it with H5N1 and H3N2.

Structural, electronic, and magnetic properties of a ferromegnetic semiconductor: Co-doped TiO$_2$ rutile
W. T. Geng,K. S. Kim
Physics , 2003,
Abstract: Room-temperature ferromagnetism has been recently discovered in Co-doped TiO$_2$ rutile. Our $ab$ $initio$ density-functional theory investigations show that the substitutional Co ions incorporated into TiO$_2$ rutile tend to cluster and then the neighboring interstitial sites become energetically favorable for Co to reside. This suggests that a Co-doped rutile containing only substitutional Co is not an appropriate reference bulk system in derterming the local environment of Co in polycrystalline (Ti,Co)O$_2$ rutile. We also find that the interstitial Co is in the low spin state and destroys the spin-polarization of the surrounding substitutional Co, hence reduces the average magnetic moment of impurity atoms.
Room-Temperature Ferromagnetism in Co-Doped TiO$_2$ Anatase: Role of Interstitial Co
W. T. Geng,K. S. Kim
Physics , 2003,
Abstract: TiO$_2$ anatase doped with Co has been recently reported to exhibit room-temperature ferromagnetism. $Ab$ $initio$ study on substitutional Co doping, however, yielded much larger magnetic moment for Co than experiment. Our calculations based on density-functional theory show that the substitutional Co ions incorporated into TiO$_2$ anatase tend to cluster and then the neighboring interstitial tetrahedral sites become energetically favorable for Co to reside, yielding a local environment more like Co$_3$O$_4$ than CoTiO$_3$. The interstitial Co destroys the spin-polarization of the surrounding substitutional Co but enhances the stability of the ferromagnetism significantly. In the absence of carriers, this room-temperature ferromagnetism can only be accounted for by superexchange interaction.
Fish Swim Bladder-Derived Porous Carbon for Defluoridation at Potable Water pH  [PDF]
John Karuga, Yusufu A. C. Jande, Hee T. Kim, Cecil K. King’ondu
Advances in Chemical Engineering and Science (ACES) , 2016, DOI: 10.4236/aces.2016.64044
Abstract: The levels of fluoride in various ground water sources in East Africa are above the World Health Organization upper limit of 1.5 mg/L. Research on diverse defluoridation technologies has proven that adsorption stands out as an affordable, efficient, and facile technology. Fish swim bladder-derived porous carbon (FBPC) activated by KOH and surface oxidized by nitric acid was successfully investigated as an adsorbent for defluoridation at portable water pH. The FBPC was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). Batch methods were used to study physiochemical parameters viz., initial fluoride concentration, temperature, adsorbate dosage, contact time and pH. Freundlich, Temkin, Langmuir and Dubinin-Radushkevich isotherms were plotted and analyzed to understand the adsorption process. Bangham, Weber Morris, pseudo first and second-order models were used to elucidate the kinetics of adsorption. Optimal conditions for fluoride removal were found to be: pH of 6, FBPC adsorbent dose of 5.0 g/L and contact time of 50 min. Flouride adsorption followed pseudo second-order kinetic model and Langmuir isotherm best describes the adsorption process.
Abnormal storm waves in the winter East/Japan Sea: generation process and hindcasting using an atmosphere-wind wave modelling system
H. S. Lee,K. O. Kim,T. Yamashita,T. Komaguchi
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2010, DOI: 10.5194/nhess-10-773-2010
Abstract: Abnormal storm waves cause coastal disasters along the coasts of Korean Peninsula and Japan in the East/Japan Sea (EJS) in winter, arising due to developed low pressures during the East Asia winter monsoon. The generation of these abnormal storm waves during rough sea states were studied and hindcast using an atmosphere-wave coupled modelling system. Wind waves and swell due to developed low pressures were found to be the main components of abnormal storm waves. The meteorological conditions that generate these waves are classified into three patterns based on past literature that describes historical events as well as on numerical modelling. In hindcasting the abnormal storm waves, a bogussing scheme originally designed to simulate a tropical storm in a mesoscale meteorological model was introduced into the modelling system to enhance the resolution of developed low pressures. The modelling results with a bogussing scheme showed improvements in terms of resolved low pressure, surface wind field, and wave characteristics obtained with the wind field as an input.
Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Sections for 6Li + 208Pb System at Near-Coulomb-Barrier Energies by using Folding Potential
W. Y. So,T. Udagawa,K. S. Kim,S. W. Hong,B. T. Kim
Physics , 2006, DOI: 10.1103/PhysRevC.75.024610
Abstract: Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous $\chi^{2}$ analyses are performed for elastic scattering and fusion cross section data for the $^{6}$Li+$^{208}$Pb system at near-Coulomb-barrier energies. A folding potential is used as the bare potential. It is found that the real part of the resultant DR part of the polarization potential is repulsive, which is consistent with the results from the Continuum Discretized Coupled Channel (CDCC) calculations and the normalization factors needed for the folding potentials. Further, it is found that both DR and fusion parts of the polarization potential satisfy separately the dispersion relation.
Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Section Data for the 9Be+28Si, 144Sm, and 208Pb Systems at Near-Coulomb-Barrier Energies using Double Folding Potential
W. Y. So,T. Udagawa,K. S. Kim,S. W. Hong,B. T. Kim
Physics , 2008,
Abstract: Based on the extended optical model with the double folding potential, in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous $\chi^{2}$ analyses are performed of elastic scattering and fusion cross section data for the $^{9}$Be+$^{28}$Si, $^{144}$Sm, and $^{208}$Pb systems at near-Coulomb-barrier energies. We find that the real part of the resultant DR part of the polarization potential is systematically repulsive for all the targets considered, which is consistent with the results deduced from the Continuum Discretized Coupled Channel (CDCC) calculations taking into account the polarization effects due to breakup. Further, it is found that both DR and fusion parts of the extracted polarization potentials satisfy the dispersion relation.
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