• Korean Journal of Materials Research
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• v.13 no.5
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• pp.303-308
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• 2003

Amorphous carbon nitride films deposited on Si(001) substrates by a plasma enhanced chemical vapor deposition (PECVD) technique using CH$_4$and $N_2$as reaction gases were thermally annealed at various temperatures under$ N_2$atmosphere, then their physical properties were investigated particularly as a function of annealing temperature. Above $600^{\circ}C$ a small amount of crystalline $\beta$-$C_3$$N_4$ phase evolves, while the film surface becomes very rough due to agglomeration of fine grains on the surface. As the annealing temperature increases, both the hardness and the $sp^3$ bonding nature are enhanced. In contrast to our expectation, higher annealing temperature results in a relatively higher friction mainly due to big increase in roughness at that temperature.

• 한국가시화정보학회:학술대회논문집
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• 2003.11a
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• pp.83-86
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• 2003

Synchrotron X-ray micro imaging technique was employed to non-invasively monitor the water flow inside xylem vessels in a bamboo leaf. The phase contrast X-ray images clearly visualized plant anatomy and the rise of a water front inside the vessels. Consecutive X-ray images taken for 60 seconds revealed water rise kinetics against gravity in the xylem of a cut dry leaf taken from a bamboo tree. For the first time, traces of water rise, variation of contact angle between water and xylem wall as well as the internal structure of xylem were obtained. In xylem vessels, a repeating flow pattern has a typical flow velocity of $30.7{\mu}m/s$ and faster flow is established intermittently. It is concluded that the transmission type of X-ray micro imaging can be used as a powerful tool to investigate the ascent of sap in the xylem vessels at a resolution higher than that of MRI.

• Korean Journal of Veterinary Service
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• v.18 no.2
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• pp.152-157
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• 1995

A total of 1050 layer and broiler chickens from 63 flocks of 21 poultry farms in South-Kyeonggi area, aged from 1 to 18 weeks, were investigated for the prevalence of Cryptosporidium baileyi infection from May 1992 to March 1993. The results have shown that 44 chickens(4.19%) were infected with C.(baileyi during the period of investigation) Fecal samples were treated by using Sheather's flotating technique and were examined under the light and phase contrast microscopy and then stained by Kinyoun method. Cryptosporidium oocysts were found in 35 out of 650 broilers(5.4%) and 9 out of 400 layer chickens(2.3%) aged mainly from 2 to 12 weeks. The regional infection rate were 4.7% in Pyeong-taek, 5.1% in An-sung and 2.3% in Yong-in, respectively. The average size of isolated oocyst was about $5.23{\times}4.92{\mu}m$ and the oocysts were orally inoculated into 2-day-old SPF chickens for the histological examination of oocyst in bursa of Fabricius. The study has concluded that C. baileyi infects chickens and oocysts were isolated in South-Kyeonggi area.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.10a
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• pp.40-44
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• 2000

$Bi_2Sr_2Ca_nCu_{n+1}O_y$($n{\geq}0$; BSCCO)thin film is fabricated via two different processes using an ion beam sputtering method i.e. co-deposition and layer-by-layer deposition. A single phase of Bi2212 can be fabricated via the co-deposition process. While it cannot be obtained by the layer-by-layer process. Ultra-low growth rate in our ion beam sputtering system brings out the difference in Bi element adsorption between the two processes and results in only 30% adsorption against total incident Bi amount by layer-by-layer deposition, in contrast to enough Bi adsorption by co-deposition.

• Membrane and Water Treatment
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• v.4 no.4
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• pp.251-263
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• 2013

The internal reflux effect on dialysis through the retentate phase of a countercurrently cross-flow rectangular module is investigated. Theoretical analysis of mass transfer in cross-flow devices with or without recycling is analogous to heat transfer in cross-flow heat exchangers. In contrast to a device without reflux, considerable mass transfer is achievable if cross-flow dialyzers are operated with reflux, which provides an increase in fluid velocity, resulting in a reduction in mass-transfer resistance. It is concluded that reflux can enhance mass transfer, especially for large flow rate and feed-concentration operated under high reflux ratio.

• ALGAE
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• v.18 no.4
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• pp.355-360
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• 2003

A Gram (-), rod-shaped bacterium in size of 1.6-2.8 $\times$ 0.4 μm was isolated from a eutrophic reservoir, which exhibited growth-inhibiting effect against a bluegreen alga (Anabaena cylindrica). This isolate showed positive reactions for catalase and oxidase, and optimal conditions of 35-40°C and pH 9.0. This isolate was designated AC-1 in this manuscript. In a mixed-culture of A. cylindrica and AC-1, their growth patterns were inversely correlated and the bluegreen algal vegetative cells completely disappeared within 24-36 hours. AC-1 showed similar lytic activity in natural water as in an artificial medium. The lytic activity of AC-1 was dependent on the photosynthetic activity of A. cylindrica. When observed under phase contrast microscope, the isolate lysed vegetative cells of A. cylindrica in scattered state in a liquid medium, whereas heterocysts have not been lysed.

• Journal of Korean Neurosurgical Society
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• v.54 no.5
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• pp.434-436
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• 2013

Isolated oculomotor nerve palsy (ONP) attributable to mild closed head trauma is a distinct rarity. Its diagnosis places high demands on the radiologist and the clinician. The authors describe this condition in a 36-year-old woman who slipped while walking and struck her face. Initial computed tomography did not reveal any causative cerebral and vascular lesions or orbital and cranial fractures. Enhancement and swelling of the cisternal segment of the oculomotor nerve was seen during the subacute phase on thin-sectioned contrast-enhanced magnetic resonance images. The current case received corticosteroid therapy, and then recovered fully in 13 months after injury. Possible mechanism of ONP from minor head injury is proposed and previous reports in the literature are reviewed.

• International Journal of Oral Biology
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• v.34 no.3
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• pp.165-168
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• 2009

Postantibiotic effect (PAE) is defined as the length of time that bacterial growth is suppressed following brief exposure to an antibiotic. In this study, the in vitro PAE, postantibiotic sub-MIC effect (PA SME) and sub-MIC effect (SME) of antibiotics on Treponema denticola ATCC 35405 were investigated. The PAE of doxycycline and metronidazole were 20.3 h and 25.0 h, respectively. The PA SMEs examined by addition of 0.1, 0.2 and 0.3X MICs during the postantibiotic phase of the bacteria for metronidazole were longer than those for doxycycline. In contrast, the SMEs for doxycycline were longer than those for metronidazole. The PA-SME and SME values increased as the concentration of antibiotics increased. The present study illustrates the existence of PAE, PA-SME and SME for several antibiotics against T. denticola, thereby extending the pharmacodynamic advantages of these antibiotics.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.19-21
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• 2006

In contrast with DC source, Fell cell has non linear characteristics that has lange voltage fluctuation due to load variation, and slow dynamic characteristics. when the loads are increase, the ripples of input and output voltage, also power densities, of inductor, capacitor, and switching devices, are bulky. This paper presents Interleaved boost converter using Fuel cell stacks, proposed converter has merits to promote power densities without increasing loss. Because each converter has same switching frequency and constant phase difference. In this paper, Interleaved boost converter was design for 1[kW], it's validity was proved by simulation and experiments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.796-800
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• 2000

Bi$_2$Sr$_2$Ca$_{n}$Cu$_{n+1}$ O$_{y}$(n$\geq$0; BSCCO) thin film is fabricated via two different processes using an ion beam sputtering method i.e. co-deposition and layer-by-layer deposition. A single phase of Bi2212 can be fabricated via the co-deposition process. While it cannot be obtained by the layer-by-layer process. Ultra-low growth rate in our ion beam sputtering system brings out the difference in Bi element adsorption between the two processes and results in only 30% adsorption against total incident Bi amount by layer-by-layer deposition, in contrast to enough Bi adsorption by co-deposition.on.n.