• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.259-263
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• 2001

There are several steps such as slicing, lapping, chemical etching and mechanical polishing in the silicon wafer production process. The chemical etching step is necessary to remove damaged layer caused In the slicing and lapping steps. The typical etching liquor is the acid mixture comprising nitric acid, acetic acid and hydrofluoric acid. At present, the waste acid is treated by a neutralization method with a high alkali cost and balky solid residue. A solvent extraction method is applicable to separate and recover each acid. Acetic acid is first separated from the waste liquor using 2-ethlyhexyl alcohols as an extractant. Then, nitric acid is recovered using TBP(Tri-butyl phosphate) as an extractant. Finally hydrofluoric acid is separated with the TBP solvent extraction. The expected recovered acids in this process are 2㏖/l acetic acid, 6㏖/1 nitric acid and 6㏖/l hydrofluoric acid. The yields of this process are almost 100% for acetic acid and nitric acid. On the other hand, it is important to recover and reuse the metal values contained in various industrial wastes in a viewpoint of environmental preservation. Most of industrial products are made through the processes to separate impurities in raw materials, solid and liquid wastes being necessarily discharged as industrial wastes. Chemical methods such as solvent extraction, ion exchange and membrane, and physical methods such as heavy media separation, magnetic separation and electrostatic separation are considered as the methods for separation and recovery of the metal values from the wastes. Some examples of the application of solvent extraction to the treatment of wastes such as Ni-Co alloy scrap, Sm-Co alloy scrap, fly ash and flue dust, and liquid wastes such as plating solution, the rinse solution, etching solution and pickling solution are introduced.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.1
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• pp.61-68
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• 2004

A reproducible transformation system via optimized regeneration media for Korean rice cultivars was established using Agrobacterium tumefeciens LBA4404 (pSBM-PPGN; gusA and bar). Although japonica rice genotypes were easier to produce transgenic plants compared to Tongil type cultivars, transformation efficiencies were not always correlated with regeneration efficiencies of non-transgenic callus on the control medium. Regeneration efficiencies of Donganbyeo, Ilmibyeo, and Manchubyeo were over 50% in non-transgenic control, however, transformation efficiencies were significantly low when only sucrose was added to the media as a carbon source. However, the medium, MSRK5SS-Pr (or MSRK5SM-Pr), that contains $5\textrm{mgL}^{-1}$ kinetin, $0.5\textrm{mgL}^{-1}$ NAA, 2 % sucrose (or maltose), 3% sorbitol, and $500\textrm{mgL}^{-1}$ proline, was the most efficient not only for regeneration of non-transgenic callus but also for regeneration of transgenic callus in the presence of L-phosphinotricin (PPT). Average transformation efficiencies of 16 Korean rice cultivars were significantly enhanced by using the optimized medium from 1.5% to 5.8% in independent callus lines and from 2.9% to 19.4% in tromsgenic plants obained. Approximately 98.9% (876 out of 885) transgenic plants obtained on optimized media showed basta resistance. Stable integration, inheritance and expression of gusA and bar genes were continued by GUS assay and PCR and Southern analysis of the bar gene. With Pst1 digestion of genomic DNA of transgenic plants, one to five copies of T-DNA segment were observed; however, 76% (19 out of 25 transgenic plants) has low copy number of T-DNA. The transformants obtained from one callus line showed the same copy numbers with the same fractionized band patterns.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.2
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• pp.187-192
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• 2013

Fatigue crack was detected from a temperature change around surface crack using the thermographic technique. Thermal gradient across the crack decreased very much due to thermal resistance of contact surface in the crack. Heat diffusion flow passing through the discontinuity was visualized in temperature by infrared camera to find and locate the crack. A fatigue crack specimen(SM-45C), which was prepared according to KS specification and notched in its center to initiate fatigue crack from the notch tip, was heated by halogen lamp at the end of one side to generate a heat diffusion flow in lateral direction. A abrupt jump in temperature across the fatigue crack was observed in thermographic image, by which the crack could be located and sized from temperature distribution.

• Journal of Agricultural Extension & Community Development
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• v.24 no.2
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• pp.143-154
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• 2017

Saemaul Undong (SM U) initiated in Korea in the 1970's is widely acknowledged as a successful model for rural community development, despite its limitations. This paper investigates the success factors of the SMU model and the lessons thereof for Sam Sang Model of Lao PDR, which appears ineffective over the years. Results show that land reforms, social ties among villages, strong institutional support and leadership and incentive system as well as "top-down" and "bottom-up" development approaches are among the factors that significantly contributed to the success of the SMU. However, rural development program would not be effective if residents are unwilling to participate. Therefore, to successfully achieve rural community development in Lao PDR, the government should through the Sam Sang model employ top-down and bottom-up approaches to enhance local participation and address the exact needs of the local people.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.158-158
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• 2009

The electrophoretic deposition(EPD) technique with a wide range of novel applications in the processing of advanced ceramic materials and coatings, has recently gained increasing interest both in academic and industrial sector not only because of the high versatility of its use with different materials and their combinations but also because of its cost-effectiveness requiring simple apparatus. Compared to other advanced shaping techniques, the EPD process is very versatile since it can be modified easily for a specific application. For example, deposition can be made on flat, cylinderical or any other shaped substrate with only minor charge in electrode design and positioning[1]. The synthesis of the nano-sized Ce0.2Sm0.8O1.9(SDC)particles prepared by aurea based low temperature hydrothermal process was investigated in this study[2].When we made the SDC nanoparticles, changed the time of synthesis of the SDC. The SDC nanoparticles were characterized with field-emission scanning electron microscope(FESEM), energy dispersive X-ray analysis(EDX), and X-ray diffraction(XRD). And also we researched the results of our investigation on electrophoretic deposition(EPD) of the SDC particles from its suspension in acetone solution onto a non-conducting NiO-SDC substrate. In principle, it is possible to carry out electrophoretic deposition on non-conducting substrates. In this case, the EPD of SDC particles on a NiO-SDC substrate was made possible through the use of a adequately porous substrate. The continuous pores in the substrates, when saturated with the solvent, helped in establishing a "conductive path" between the electrode and the particles in suspension[3-4]. Deposition rate was found to increase its increasing deposition time and voltage. After annealing the samples $1400^{\circ}C$, we observed that deposited substrate.

• Korean Journal of Veterinary Research
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• v.34 no.1
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• pp.85-91
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• 1994

A study on the isolation of Yersiniae from the feces of wild animals(mammals 376, birds 19 and reptiles 13) in zoo and the biotype and serotype and susceptibility of 12 antibiotics was carried. Out of 408 animals, Yersiniae were isolated from 28 animals(6.9%). Of 28 isolates, 27 isolates(96.4%) were Y. enterocolitica and 1(3.6%) was Y. kristensenii. According to the species, 25(6.6%) of Y. enterocolitica and 1(0.3%) of Y. kristensenii were isolated from 376 mammals, 2(15.4%) of Y. enterocolitica from 13 reptiles but not isolated from 19 birds. According to the eating pattern, 8(5.2%) of Y. enterocolitica were isolated from 155 carnivora, 13(10%) of Y. enterocolitica from 123 herbivora, and 6(4.9%) of Y. enterocolitica and 1(0.8%) of Y. enterocolitica from 123 omnivora. Out of 27 isolates of Y. enterocolitica, all were biotype 1. And predominant serotype was 0:21(40.7%), and 0:5(37.0%), 0:6(11.1%), 0:1(3.7%), 0:9(3.7%) and untypable(3.7%). Yersiniae isolated from zoo animals were resistant to cephalothin(100%), ampicillin(96.4%), carbenicillin(96.4%) and tetracycline(14.3%) and streptomycin(3.6%) and susceptible to chloramphenicol(100%), colistin(100%), gentamicin(100%), kanamycin(100%), nalidixic acid(100%), polymyxin B(100%) and tobramycin(100%). The predominant multiple resistance pattern was Am-Cf-Cb(82.1%), and Am-Cf-Cb-Te(10.7%) and Am-Cf-Cb-Te-Sm(3.7%).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.9B
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• pp.908-913
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• 2009

Mobile phones became important household appliance that cannot be without in our daily lives. And the short messaging service (SMS) in these mobile phones is 1.5 to 2 times more than the voice service. However, the spam filtering functions installed in mobile phones take a method to receive specific number patterns or words and recognize spam messages when those numbers or words are present. However, this method cannot properly filters various types of spam messages currently dispatched. This paper proposes a more powerful and more adaptive spam filtering system using SVM and thesaurus. The system went through a process of isolating words from sample data through pro-processing device and integrating meanings of isolated words using a thesaurus. Then it generated characteristics of integrated words through the chi-square statistics and studied the characteristics. The proposed system is realized in a Window environment and the performance is confirmed through experiments.

• Food Science of Animal Resources
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• v.36 no.6
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• pp.819-828
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• 2016

Muscle fiber characteristics account for meat quality and muscle fibers are mainly classified into three or more types according to their contractile and metabolic properties. However, the majority of previous studies on bovine skeletal muscle are based on myosin ATPase activity. In the present study, the differences in the characteristics of muscle fibers classified by the expression of myosin heavy chain (MHC) among four bovine skeletal muscles such as longissimus thoracis (LT), psoas major (PM), semimembranosus (SM) and semi-tendinosus (ST) and their relationships to beef quality were investigated. MHCs 2x, 2a and slow were identified by LC-MS/MS and IIX, IIA and I fiber types were classified. PM, which had the smallest size and highest density of fibers regardless of type, showed the highest myoglobin content, CIE $L^*$, $a^*$, $b^*$ and sarcomere length (p<0.05), whereas ST with the highest composition of IIX, showed high shear force and low sarcomere length (p<0.05). The correlation coefficients between muscle fiber characteristics and meat quality showed that type IIX is closely related to poor beef quality and that a high density of small-sized fibers is related to redness and tenderness. Therefore, the differences in meat quality between muscles can be explained by the differences in muscle fiber characteristics, and especially, the muscles with good quality are composed of more small-sized fibers regardless of fiber type.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1162-1166
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• 2001

NiZn-ferrite was synthesized from waste catalysts, which were produced from styrene monomer process and buried underground as an industrial wastes, and its magnetic properties were investigated. Nickel oxide and zinc oxide powders were mixed with finely ground waste catalysts, and spinel type ferrite was obtained by calcination at 900$\^{C}$ and sintering at 1230$\^{C}$ for 5 hours. The intial permeability was measured and reflection loss was calculated from S-parameters for the composition of Ni$\_$x/Zn$\_$1-x/Fe$_2$O$_4$(x=0.36, 0.50, 0.66). NiZn-ferrite synthesized from waste iron oxide catalyst showed a feasibility for the use as electromagnetic wave absorber in X-band.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.3
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• pp.265-272
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• 1989

The objective of this study was to investigate the contents of some minerals in vegetable foods by a highly sensitive Neutron Activation Analysis. Chinese Chives, Amaranth, Mugwort, Ginger, Garlic, Root of bellflower, Cultured Duduk, Wild Duduk and Cortinellus-edodes were chosen as experimental materials for this study. The contents of potassium, copper, molybdenum, and bromum were 7099.1mg%, 104.8 ppm, 45.4ppm and 40.4ppm in Chinese Chives. Chinese Chives, Amaranth and Mugwort were more abundant with iron, coppr and cobalt other than vegetable foods. The ratio of sodium to potassium for Chinese Chives was 1 to 796, for Mugwort : 1 to 147 and for Garlic : 1 to 148. As the Neutron Activation Analysis Technique was able to detect gold, samarium, bromum, lanthanum and scandium from vegetable foods, this technique is very useful to analyse the infinitestimal elements in foods.