• 대한기계학회논문집B
• /
• 제29권3호
• /
• pp.376-383
• /
• 2005

In the paper we investigate characteristics of a transitional behavior from a premixed flame to a triple flame in a lifted flame according to the change of equivalence ratio. In previous study, we showed that the stabilized laminar lifted flame regime is categorized by regimes of premixed flame, triple flame and critical flame. A gas-chromatograph is used to measure concentration field, a smoke-wire system is used to measure streak line, and a PIV system is used to measure velocity field in lifted flame. In the visualization experiment of smoke wire, the flow divergence and redirection reappeared in premixed flame as well as triple flame. Thus we cannot express the flame front of lifted flame has a behavior of triple flame with only flow divergence and redirection. In PIV measurement, flow velocity for those three flames has minimum value at the tip of flame front. To differentiate triple flame and premixed flame, $\Phi$ value of partially premixed fraction is employed. The partially premixed fraction $\Phi$ was constant in premixed flame. In critical flame small gradient appears over the whole regime. In triple flame, typical diffusion flame shape is obtained as parabolic distribution type due to diffusion flame trailing.

• 대한의용생체공학회:의공학회지
• /
• 제32권3호
• /
• pp.257-263
• /
• 2011

Sparse-view CT imaging is considered to be a solution to reduce x-ray dose of CT. Sparse-view CT imaging may have severe streak artifacts that could compromise the image qualities. We have compared quality of sparseview images reconstructed with two representative iterative reconstruction techniques, SIRT and TV-minimization, in terms of image error and edge preservation. In the comparison study, we have used the Shepp-Logan phantom image and real CT images obtained with a micro-CT. In both phantom image and real CT image tests, TV-minimization technique shows the best performance in error reduction and preserving edges. However, the excessive computation time of TV-minimization is a technical challenge for the practical use.

• 한국표면공학회지
• /
• 제43권4호
• /
• pp.176-179
• /
• 2010

The InAs thin films were grown on GaAs(100) substrate with $2^{\circ}C$ tilted toward [$0\bar{1}\bar{1}$] with different As beam equivalent pressure (BEP) by using molecular beam epitaxy. Growth temperature and thickness of the InAs thin films were $480^{\circ}C$ and 0.5 ${\mu}m$, respectively. We studied the relation between the As BEP and the properties of InAs thin films. The properties of InAs thin films were observed by reflection high-energy electron diffraction (RHEED), optical microscope, and Hall effect. The growth, monitored by RHEED, was produced through an initial 2D (2-dimensional) nucleation mode which was followed by a period of 3D (3-dimensional) island growth mode. Then, the 2D growth recovered after a few minutes and the streak RHEED pattern remained clear till the end of growth. The crystal quality of InAs thin films is dependent strongly on the As BEP. When the As BEP is $3.6{\times}10^{-6}$ Torr, the InAs thin film has a high electron mobility of 10,952 $cm^2/Vs$ at room temperature.

• Archives of Pharmacal Research
• /
• 제21권4호
• /
• pp.440-444
• /
• 1998

A series of 6-(N-arylamino)-7-methylthio-5,8-quinolinedione derivatives 4a-4l was newly synthesized for the evaluation of antifungal activity. 6-(N-Arylamino)-7-methylthio-5,8-quinolinediones were prepared by regioselective nucleophilic substitution of 6,7-dichloro-5,8-quinolinediones with arylamines in the presence of $Ce^{3+}$, and $Na_2$S/dimethylsulfate. The MIC values of 4a-4l were determined for antifungal susceptibility in vitro against Candida species by agar streak method. The derivatives 4a-4l had generally potent antifungal activities against all human pathogenic fungi. Especially they had the most potent activity against C. krusei at 12.5-0.8 $\mu\textrm{g}$/ml. Compounds 4d, 4g, 4h, 4j and 4k had more potent antifungal activities than fluconazole. Compounds 4g and 4h completely inhibited the fungal growth at 0.8-6.3 $\mu\textrm{g}$/ml against all Candida species, while fluconazole inhibited the growth at 25 $\mu\textrm{g}$/ml. The compounds such as 4g and 4h containing an N-(4-bromo-2-methylphenyl)- or N-(4-bromo-3methylphenyl)amino substituent exhibited the most potent antifungal activities.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집
• /
• pp.533-536
• /
• 2001

Single crystal cubic silicon carbide(3C-SiC) thin film were deposited on Si(100) substrate up to a thickness of 4.3 $\mu\textrm{m}$ by APCVD(atmospheric pressure chemical vapor deposition) method using hexamethyildisilane(HMDS) at 1350$^{\circ}C$. The HMDS flow rate was 0.5 sccm and the carrier gas flow rate was 2.5 slm. The HMDS flow rate was important to get a mirror-like. The growth rate of the 3C-SiC films was 4.3 $\mu\textrm{m}$/hr. The 3C-SiC epitaxical layers on Si(100) were characterized by XRD(X-ray diffraction), raman scattering and RHEED(reflection high-energy electron diffraction), respectively The 3C-SiC distinct phonons of TO(transverse optical) near 796 cm$\^$-1/ and LO(longitudinal optical) near 974${\pm}$1 cm$\^$-1/ were recorded by raman scattering measurement. The deposition films were identified as the single crystal 3C-SiC phase by XRD spectra(2$\theta$=41.5$^{\circ}$). Also, with increase of films thickness, RHEED patterns gradually changed from a spot pattern to a streak pattern

• 한국식물병리학회지
• /
• 제14권2호
• /
• pp.136-144
• /
• 1998

Many cloves of native cultivated garlics in Korea were found to be infested by mites when observed with stereo-microscope. The mite was identified by light and scanning electron microscopic observation as Aceria tulipae. Surveying viruses from the vegetatively propagated garlic, highly flexuous, filamentous particles (700∼800 nm) were detected in Aceria tulipae, local lesions of Chenopodium murale after sap transmissions, mosaic garlic leaves inoculated with mite-borne virus by transmission of Aceria tulipae and naturally infected garlic leaves. The mite-borne virus isolated did not react with antisera of aphid-borne potyviruses (LYSV-G, LYSV-L, WoYSV) or carlavirus (GLV), but reacted with antisera of garlic mite-borne viruses (GV-C, GMbMV). In ultratin sections of mite-borne virus infected garlic tissues, aggregates of virus particles and membrane proliferations were found in the parenchyma cells, but cytoplasmic cylindrical inclusions were not observed. Heavily mite-infested plants showed streaking and malformation due to mite feeding. The mite-borne virus was identified as garlic mite-borne mosaic virus (GMbMV), the mite-borne genus Rymovirus of the Potyviridae by mite transmission, morphology of virus particles, serological relationships, host range, distribution pattern of virus particles and inclusion bodies in the infected cells. The results demonstrate that mite-borne virus is one of the major viruses infecting native cultivated garlic plants showing mosaic or streak symptoms in Korea.

• Animal Systematics, Evolution and Diversity
• /
• 제31권2호
• /
• pp.122-127
• /
• 2015

The subfamily Ennominae is one of the most species-rich taxa of Geometridae that include more than 9,700 species worldwide and over 280 species in South Korea. Herein, we present the first report of five species of Ennominae. Abraxas flavisinuata can be characterized by the white wings, a thick black postmedial line that is medially and dorsally broken with an orange band, large rounded black discal dots on the forewing, and a black dotted postmedial line on the hindwing. Lomographa claripennis can be characterized by the whitish wings, the black undulating postmedial line as well as the minute blackish discal dot on the forewing, and the black undulating postmedial line with a minute black discal dot on the hindwing. Arichanna tetrica can be characterized by the grayish forewings, thick black transverse ante- and postmedial lines, a large blackish discal dot, whitish apical streak on the forewing, and scattered black dots on the whitish hindwing. Apocleora rimosa can be characterized by the brown ground color of the fore- and hindwings, the black slanted ante- and postmedial lines of the forewing, and two black medial lines on the hindwing. Ourapteryx japonica can be characterized by the white wings, the dark brown transverse ante- and postmedial lines with a long discal dot on the forewing, and the dark brownish transverse antemedial line as well as a termen that has a sharp white tail with one large dark reddish dot and one small black dot on the hindwing.

• Archives of Pharmacal Research
• /
• 제20권6호
• /
• pp.586-589
• /
• 1997

Antifungal activities of 6-[(N-4-bromophenyl)amino]-7-chloro-5,8-quinolinedione (RCK7) were tested. The MIC values of RCK7 were determined for antifungal suceptibility, in vitro against Aspergillus niger, Cryptococcus neoformans and Trichophyton mentagrophyte by standard agar streak method. In vitro, RCK7 showed more potent antifungal activity than fluconazole and ketoconazole. Also, RCK7 was tested for in vivo antifungal activity in the treatment of systemic infection with Candida albicans in normal mice. The therapeutic potential of RCK7 had been assessed by evaluating their survival rate against systemic infections compared with that of ketoconazole. $ED_{50}$ of intraperitoneally administered RCK7 ws $2.05{\pm}0.30mg/kg$ but that of ketoconazole was $8.00{\pm}0.73 mg/kg$, respectively. When RCK7 was administered intravenously at the $ED_{50}$(2.05 mg/kg). the colony counts of Candida albicans in the liver after 7 days and 14 days were reduced as likely as ketoconazole at the $ED_{50}(8.00 mg/kg)$, and the better survival rates than ketoconazole's were achieved after 14 days. The results suggest that RCK7 may be a potent antifungal agent.

• Journal of Korean Neurosurgical Society
• /
• 제64권3호
• /
• pp.329-339
• /
• 2021

It has been recognised for over a century that the events of gastrulation are fundamental in determining, not only the development of the neuraxis but the organisation of the entire primitive embryo. Until recently our understanding of gastrulation was based on detailed histological analysis in animal models and relatively rare human tissue preparations from aborted fetuses. Such studies resulted in a model of gastrulation that neurosurgeons have subsequently used as a means of trying to explain some of the congenital anomalies of caudal spinal cord and vertebral development that present in paediatric neurosurgical practice. Recent advances in developmental biology, in particular cellular biology and molecular genetics have offered new insights into very early development. Understanding the processes that underlie cellular interactions, gene expression and activation/inhibition of signalling pathways has changed the way embryologists view gastrulation and this has led to a shift in emphasis from the 'descriptive and morphological' to the 'mechanistic and functional'. Unfortunately, thus far it has proved difficult to translate this improved knowledge of normal development, typically derived from non-human models, into an understanding of the mechanisms underlying human malformations such as the spinal dysraphisms and anomalies of caudal development. A paediatric neurosurgeons perspective of current concepts in gastrulation is presented along with a critical review of the current hypotheses of human malformations that have been attributed to disorders of this stage of embryogenesis.

• 대한방사선기술학회지:방사선기술과학
• /
• 제44권3호
• /
• pp.231-237
• /
• 2021

The ongoing coronavirus disease 2019 (COVID-19) pandemic has highlighted the importance of hospital hygiene and infection control in hospital settings. To raise hygiene awareness among ultrasound technicians, we evaluated the hygiene status of an ultrasound room, in comparison with that of objects used in daily life. Using the swab method, the following surfaces were examined: eight surfaces in the ultrasound room including the ultrasound probes (convex, linear, sector, 3D), ultrasound track ball, ultrasound keyboard, ultrasound gel (sealed and in use) and pillow as well as four surfaces of everyday objects including subway handles, common computer keyboards, common computer mouse, and cell phones. The streak plate technique was used for inoculation into media, which was observed for the formation of bacterial colonies following incubation for 24 h. Six bacterial strains were detected from objects used in the ultrasound room, including methicillin-resistant Staphylococcus aureus. Four strains of bacteria were detected on surfaces of everyday objects. The equipment and accessories used in an ultrasound room can act as vehicles for infecting patients. Establishment of standardized hygiene protocols and periodic training of the staff are recommended to avoid cross-infection.