• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.514-519
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• 2020

Graphite materials for lithium ion battery anode materials are the most commercially available due to their structural stability and low price. Recently, research efforts have been conducted on carbon coatings by improving side reactions at the edge site of carbon materials. The carbon coating process has classified into a CVD by chemical reaction, wet coating process with solvent and dry coating by mechanical impact. In this paper, the rapid crush/coating process was used to solve the problem of which only few parts of the carbon precursor (pitch) can be used and also environmental problems caused by solvent removal in the wet coating process. When the ratio of needle coke to pitch was 8 : 2 wt%, and the rapid crush/coating process was carried out, it was confirmed that the fracture surface was coated by pitch. The pitch-coated sample was treated at 2400 ℃ and 41.8% improvement in 10C/0.1C rate characteristic was observed. It is considered that the material simply manufactured through the simple crush/coating process can be used as an anode electrode material for a lithium ion battery.

• Journal of the Korean GEO-environmental Society
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• v.14 no.1
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• pp.15-22
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• 2013

5 each permeable and impermeable debris dams were selected to analyze the characteristics of dredging and sedimentation according to facility type in Inje, Gangwon. Field tests for the ground water table and sedimentation characteristics of the selected dams were performed. Furthermore, data of the dredging amount, storage capacity, and drainage area were analyzed for the 51 more debris control facilities. From the results of field tests, it was found that the storage capacity of impermeable debris dam could be not enough when the large debris flow is produced since sediments are accumulated even if large debris flow was not occurred. Drainage can be a problem since the ground water table of impermeable debris dam was reached to the surface of ground. However, it was found that the ground saturation should not occur at heavy rain since ground water table of permeable debris dam was located in lower part of buttress. Furthermore, from the analysis results of relation among the dredging amount, basin area, and capacity of debris control facility, it was found that size of debris control facility was not reflected by the basin area. Effective planning and construction should be accomplished for the future since the real sedimentation amount was not significant even though large debris dams were constructed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.273-281
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• 2007

This paper presented design for a dipole antenna operated at 900 MHz band RFID tag, and antenna performance varied by the sticked material was experimentally evaluated. When dipole antenna was sticked by the material having a difffrent electric characteristic such as dielectric material, fero-magnetic material and conductor, variations of antenna return loss and radiation pattern according to the sticked material kinds, size, and height between antenna and the sticked plate were experimentally observed and evaluated. When antenna was sticked by dielectric surface, the measured return loss and radiation pattern by affection of different dielectric permittivity ratio showed resonant frequency shift of about 40 MHz and relative attenuation of 1 dB to 3 dB. Even though frequency shift by size variation of the sticked plate was observed, the measured radiation pattern of dipole antenna located on the sticked plate was similar with one without backside plate. In the case of conductor or fero-magnetic material as the sticked ground plate, because of frequency shift and phase difference by distance between dipole antenna and the sticked ground plate, amplitude decrease of radiation pattern at 910 MHz was observed about 5 dB above.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.595-599
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• 2009

Sarcocystis grueneri-like sarcocysts were found from the cardiac muscles of a rearing red deer (Cervus elaphus) carcass in Korea. In the light microscopical examination of sarcocysts, they were oval to spherical cysts and 90-170$\times$110-380 ${\mu}m$ in size. However, there was no inflammation and myofiber degeneration. In the transmission electron microscope, these cysts were located within the sarcoplasm of the host cell and filled with merozoites. The sarcocysts were enclosed by a very thin wall (0.45-0.6 ${\mu}m$ thick) that consists of protrusions and ground substance. The primary cyst wall formed numerous strip-like protrusions which were 0.2-0.3 ${\mu}m$ wide and up to 4.2 ${\mu}m$ long. The protrusions were running in parallel with the surface of the cyst. A characteristic of the cyst wall was absent of fibrils inside the protrusions. Merozoites in the compartment measured about $15\times4\;{\mu}m$. The merozoite consisted of four regions: micronemes and rhoptries, amylopectin granule, nucleus, and amylopectin granules. The number of rhoptry was counted in 7-13.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.586-590
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• 2009

Horsehair worms (Chordodes koreensis) develop as parasites in the bodies of grasshoppers, crickets, cockroaches, and some beetles. Chordodes koreensis is an accidental parasite of humans, livestock, or pets and poses no public health threat. The male of Chordodes koreensis in the later larval stage from canine vomitus was investigated by the scanning and transmission electron microscopy. In cross sections, the body wall is composed of four components namely epicuticle, cuticle, epidermis, and muscle layers. The parenchymal tissue fills the rest of the body and surrounds the visceral organs such as intestine, and ventral nerve cord but testes were not found. The epicuticle is a thin superficial layer whose surface shows rows of polygonal elevations called areoles. The cuticle has 17 layers of collagenous fibers spirally wound about the long axis of the worm. The section through the cuticle reveals the layers of large fibers cut obliquely lengthwise, alternating with layers of fibers sectioned obliquely crosswise. The layers of large fiber formed a double helix about longitudinal axis of the worm. The epidermis is a single layer. The muscles were interrupted by the nervous lamella in the only midventral portion. The medulla of muscle plate is composed of lightly stained cytoplasm, mitochondria, weakly developed endoplasmic reticulum, and glycogen granules. Between the medulla of a cell and the plasmalemma lies a broad cortical zone of myofilaments. The circular muscles are absent. The characteristic feature of the cytoplasm is that there was no content in peripheral mesenchyme, but was an abundance of large clear vacuoles which give the cytosome a foamy appearance. The nucleus of mesenchyme is not easily identified in our specimens.

• Elastomers and Composites
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• v.45 no.2
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• pp.112-121
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• 2010

In this study, styrene butadiene rubber(SBR)/organoclay nanocomposites were manufactured using the latex method with 3-aminopropyltriethoxysilane(APTES) as a modifier. The X-ray diffraction(XRD), transmission electron microscopy(TEM) images, Fourier transform infrared(FTIR) spectroscopy, swelling ratio and mechanical properties were measured in order to study the interaction between filler and rubber according to the mixing temperature in the internal mixer. In the case of SBR/APTES-MMT compounds, the dispersion of the silicates within the rubber matrix was enhanced, and thereby, the mechanical properties were improved. The characteristic bands of Si-O-C in APTES disappeared after hydrolysis reaction in the MMT-suspension solution and the peak of hydroxyl group was increased. Therefore the formation of chemical bonds between the hydroxyl group generated from APTES on the silicate surface and the ethoxy group of bis(triethoxysilylpropyl) tetrasulfide(TESPT) was possible. Consequently, the 300% modulus of SBR/APTES-MMT compounds was further improved in the case of using TESPT as a coupling agent. However, the silanization reaction between APTES and TESPT was not affected significantly according to the increase of mixing temperature in the internal mixer.

• Korean Journal of Microbiology
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• v.33 no.3
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• pp.193-198
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• 1997

Microorganisms capable of producing biosurfactant were isolated from oil-contaminated soils and seawater. Among them, the selected strain SW1 was identified as Pseudomonas sp. by taxonomical characteristic tests, and so tentatively named Pseudomonas sp. SWI. The optimal temperature and initial pH for biosurfactant production were TEX>30^{\circ}C.$ and 7.0, respectively. The optimal medium composilion for the production of biosurfactant by Pseudomonas sp. SW1 were hexadecane of 2.0%, yeast extract of 0.04%, $K_{2}HPO_4$ of 0.02%, $KH_2PO_4$ of 0.03% and $MgSO_4$ center dot $7H_2O$ of 0.04%, respectively. Under the above conditions, minimum wrface tension was 32 mN/m after incubation of 2 days. The biosurfactant was produced during initial stationary phase in the optimal medium. Pseudotnonas sp. SWl utilized various hydrocarbons such as Bunker oils, n-alkanes and branched alkanes as a sole carbon source.

• Korean Journal of Materials Research
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• v.11 no.5
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• pp.405-412
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• 2001

Corrosion tests were carried out in $360^{\circ}C$ water and $360^{\circ}C$ 70ppm LiOH solution to investigate the corrosion behavior of new zirconium alloys (Zr-0.4Nb-0.8Sn-xFeCrMn, Zr-0.2Nb-1.1Sn-xFeCrMn, Zr-1.0Nb-xFeCu). Microstructures of tested alloys were analyzed by optical microscope and TEM. The cross-sectional surface and crystalline structure of the oxide layer were analyzed by SEM and XRD. From the results of corrosion test, all the alloys showed higher corrosion rates in $360^{\circ}C$ 70ppm LiOH aqueous solution thats in $360^{\circ}C$ water. Especially, high Nb-containing alloy exhibited the acceleration of corrosion rate in LiOH solution. The low Nb- and Sn-added alloys showed better corrosion resistance than the Sn- free high Nb alloy. from the effect of final annealing on the corrosion, it was observed that the partially recrystallized alloys showed better corrosion resistance than fully recrystallized alloys. This would be related to the size and distribution of the second phase particles.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.130-137
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• 2005

This research programme include investigation of the adsorption behavior of heavy metals and VOCs by Pyrolysis char for using landfill cover material. The volatile potions in the sludge gasified during the pyrolysis period and gave birth to porosity throughout the matrix. The result of the ad/desorption experiment of nitrogen to find out the formation of some pore by the gasification of the volatile matter, we can certify that the pyrolysis char($14.56\;m^2/g$) has increased twice more than the organic wasted sludge($6.68\;m^2/g$) in specific surface area. The pyrolysis char has the adsorption characteristic of medium type of Type II and V in BDDT classification, and showed a little micro pore. In the adsorption experiment of ethylbenzene and toluene, as a result of applying the Freundlich adsorption isotherms, the pyrolysis char was higher in the adsorptivity of ethylbenzene and toluene than the granite and the organic wasted sludge. The results of the heavy metal adsorption test for the char indicated that it had some ability of adsorption. It is suggest that pyrolysis char has some advantages for utilizing as landfill covers because the pyrolysis char can adsorb/absorb hazardous substances from the landfill sites and inhibit the ground water and soil contamination.

• Restorative Dentistry and Endodontics
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• v.12 no.1
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• pp.39-49
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• 1986

The purpose of this study was to observe characteristic properties through the polarization curves and SEM images from 4 different types of amalgam obtained by using the potentiostats (Princeton EG & G) & SEM (Jeol/35), and to investigate the degree of corrosion on the oxidation peak of the each phase of amalgam. After each amalgam alloy and Hg was triturated as the direction of the manufacturer by means of the mechanical amalgamator (Shofu Co.), the triturated mass was inserted into the cylindrical metal mold which was 12mm in diameter and 10.0mm in height and was condensed by using routine manner. The specimen was removed from the mold and stored at room temperature for about 24 hours. The standard surface preparation was routinely carried out. Anodic polarization measurement was employed to confirm the corrosion behaviour of the amalgams in a 0.9% saline solution (P.H: 6.8-7.0) at $37^{\circ}C$. The initial rest potential (corrosion potential) was determined after 30 minutes of immersion of specimen in electrolyte, and the potential scan was begun at the point of 100mV cathodic from the corrosion potential. The scan rate was 0.17mV/sec. in the study to observe the degree of corrosion of each phase. SEI and EPMA images on the determined oxidation peaks of each amalgam were observed. The results were as follows: 1. In the four anodic polarization curves, low copper amalgams have three oxidation peaks and high copper amalgams have two oxidation peaks, -270mV, +26mV and +179mV(SEC) in the low copper lathe cut, and -300mV, +39mV and +163mV(SEC) in the low copper spherical. -4mV and +154mV(SEC) in the Dispersalloy, and +17mV and +180mV(SEC) in the Tytin as high copper amalgams. 2. ${\gamma}_2$ phase in the low copper amalgam and ${\eta}$ phase in the high copper amalgam were the most corrodible phases and Ag-Cu eutectic in high copper amalgam was the most slowly corroded phase. 3. Low copper amalgam was more susceptible in corrosion than high copper amalgam.