• Atmosphere
• /
• v.17 no.4
• /
• pp.349-364
• /
• 2007

The main purpose of this study is to examine the sensitivity of the WRF (Weather Research and Forecasting) in the wind field to the steepness of mountains in the case with a strong downslope wind occurred in the Yeongdong province. We conducted WRF simulations for February 13 2006. The initial and boundary data are from the NCEP/NCAR $1^{\circ}{\times}1^{\circ}$ GDAS. Arbitrary terrains of the mountains with a symmetric orography and an asymmetric one with steeper leeward slope, were introduced to examine the sensitivity of the shape of the mountains. The simulation with an asymmetric terrain results in stronger maximum surface wind by about $10ms^{-1}$ than with a symmetric terrain, especially in the narrow region from the peak to ~ 4 km away in the downstream. However, the maximum surface wind speed is weaker by $20ms^{-1}$ than with a symmetric terrain away from the narrow peak region. This indicates that the steeper slope leads to the intensification of downslope wind in the narrower region leeward. In addition, for the simulation with an asymmetric terrain, the strength of wave breaking is greater and the Lee wave is more dominant than for that with a symmetric terrain.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.2
• /
• pp.49.1-49.1
• /
• 2015

Star formation in galaxies that lie in dense environment tends to increase as the redshift of the cluster increases. At z~1.4, the situation turns to be complex; some clusters still harbor galaxies with vigorous star formation, and others are populated with relatively old, massive galaxies. We present the result from narrow-band photometric study of the fields around the radio galaxy 6CE 1100+3505 at z=1.44. Deep H- and H-narrow band data have been obtained using CFHT/WIRCAM which cover the corresponding wavelengths for redshifted $H{\alpha}$. While the number of IRAC 3.6, and $4.5{\mu}m$ selected sources show clear excess within the central ~1Mpc area from the radio galaxy, number of galaxies identified to show excess in H-narrow band is very small. We discuss the possible integrated star formation rate in this overdense structure, and the implication to the evolution of cosmic star formation rate as a function of environment.

• Journal of Mechanical Science and Technology
• /
• v.15 no.7
• /
• pp.906-920
• /
• 2001

This paper presents three-dimensional mean velocities, turbulent intensities and Reynolds shear stresses measured in the Y-Z plane of the gas swirl burner with a cone type baffle plate by using an X-type hot-wire probe. This experiments is carried out at the flow rate of 450ℓ/min which is equivalent to the combustion air flow rate necessary to heat release 15,000 kcal/hr in a gas furnace. Mean velocities and turbulent intensities etc. show that their maximum values exist around the narrow slits situated radially on the edge of and in front of a burner. According to downstream regions, they have a peculiar shape like a starfish because the flows going out of the narrow slits and the swirl vanes of an inclined baffle plate diffuse and develop into inward and outward of a burner. The rotational flow due to the inclined flow velocity going out of swirl vanes of a cone type baffle plate seems to decrease the magnitudes of mean velocities V and W respectively by about 30% smaller than those of mean velocity U. The turbulent intensities have large values of 50%∼210% within the range of 0.5

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.22 no.6
• /
• pp.58-62
• /
• 1985

Analytical threshold voltage model of small size ion-implanted MOSFET's is proposed. Yau's model which is only applicable to MOSFET's with constant doping concentration was modified to handle the MOSFET's with nonuniform channel doping concentration and bird's beak, whereby the short and narrow-channel effect was quantitively described. Threshold voltage model for short-channel MOSFET's was derived by approximating the SUPREM result of channel impurity profile to a 2-step profile, and the narrow width be-haviour was successfully described using thr'weighting factor'to accommodate the doping profile in the bird's beak region.

• Journal of Plant Biotechnology
• /
• v.39 no.1
• /
• pp.75-80
• /
• 2012

$Kalopanax$ $pictus$ is a long-lived deciduous perennial tree in the family Araliaceae mainly distributed in the East Asia. In Korea, this species is of ecological and medical importance. Because typical populations of this species are small and distributed in patches, $K.$ $pictus$ has been considered as a narrow habitat species. To understand the genetic diversity and population structure of this species, the sequence variation of the nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region was analyzed among 18 different $K.$ $pictus$ populations in the present investigation. The nrDNA ITS sequences of Korean populations investigated in this study showed identical of 616 bp in length, and no any nucleotide variation was found in the entire nrDNA ITS region sequence. This result suggested that the $K.$ $pictus$ populations in Korea might belong to the same isolate, and no mutation was found in the nrDNA ITS region. Compared with other known ITS sequence sources from $K.$ $pictus$ populations, only four variable nucleotide sites were found within the entire ITS region. Very narrow genetic diversity appearing in the population level of $K.$ $pictus$ makes us hypothesize that their relatively isolated habitats. The long-lived traits might be one main reason. However, another probability was that the nr-DNA ITS region might be noneffective in classifying populations of $K.$ $pictus$. Thus, to further understand the phylogenetic relationship of $K.$ $pictus$ populations, more samplings should be performed based on more DNA sequences.

• Fashion & Textile Research Journal
• /
• v.17 no.2
• /
• pp.191-202
• /
• 2015

The purpose of this study is to examine the form of the clothing of the Scythians who lived in the northern region of the Black Sea. This study refers to data, which has been extracted from reviews of literature, articles and catalogs of Scythian exhibitions held in Germany, a country where famous Scythian research was collected and analyzed. Results of this study are as follows: Regarding the basic form, there was no change in the appearance of the Scythian clothes which can be linked to social classes and regional background. But the detailing of the clothes changed. Russian archaeologist Klocko has stated that decorative bands of ancient costume appear to depend on the construction of ancient clothing. I have analyzed the upperjacket of Scythians with the decorative bands based on the research of Klocko. From this analysis could be observed that decorative bands of upperjacket had also been varied depending on their region and their social status. The decoration of the revers of upperjacket differs according to social status. According to their width, trousers were classified in types; in narrow and wide. The basic set up of the narrow-type is as follows: the trouser is divided into voluminous straight forms and leggings in close contact with the legs. The width of a trouser differs according to the social status of Scythians and from the region where they lived. Regional differences could be observed more significantly, than differences resulting from social status.

• The Journal of Korean Academy of Prosthodontics
• /
• v.60 no.1
• /
• pp.119-126
• /
• 2022

Mini-implant has been reported as an alternative method to conventional diameter implants in the treatment of mandibular anterior region with narrow ridge. However, one-piece type mini-implant showed biological and technical complications, such as peri-implantitis by residual cement and prosthetic detachment. Recently, one-piece type mini-implant with additional retentive structure has been introduced to increase the retention and stability of the mini-implant. The mini-implant is based on spreading the upper retentive structure with a spreader and connected it with the inner surface of the zirconia prosthesis. In two cases, we tried to reduce these complications through the mini-implant on the narrow mandibular anterior region, and it was possible to reduce the overall treatment period through a digital system. In this case report, restoration using the digital mini-implant system showed improvement of patient satisfaction on the aspect of function and esthetic in the narrow mandibular anterior region.

• Tribology and Lubricants
• /
• v.2 no.2
• /
• pp.12-19
• /
• 1986

Using emulsion lubricant whose cooling effect and incombustibility are good and which is economical, I investigated lubricative mechanism and the behavior of scattered particles in the elastic fluid lubrication region with the line contact between rollers and plates and the light interference system. The results of the study are as follows: (1) The flow in the squeeze oil film is considered as comparatively wide clearance and narrow one, and in the former case the effect of the distribution of particles and the velocity on the flow. In the latter case, emulsion particles stay in the clearance an the oil film changes with the decrease of the oil film thickness. (2) In the wide clearance the velocity difference of the flow O/W or W/O emulsion is inverse proportional to the particle size. In the narrow clearance the distribution of the remained drops is different from one another and the scattered particles change more easily in O/W type than in W/O type. (3) At the beginning of the EHL the stagnation region with slow flowing velocity exists and the behavior at the region is different depending on the particle size. (4) By observing the dischromatic light interference line, emulsion oil passing through EHL region and the crack behavior at the beginning of EHL were found.

• Proceedings of the IEEK Conference
• /
• 1998.06a
• /
• pp.677-680
• /
• 1998

In this paper, we proposed a lwo bit rate subband coding with adaptive vector quantization using the correlation between motion vector and block energy in subband. In this method, the difference between the input signal and the motion compensated interframe prediction signal is decomposed into several narrow bands using quadrature mirror filter (QMF) structure. The subband signals are then quantized by adaptive vector quantizers. In the codebook generating process, each classified region closer to the block value in the same region after the classification of region by the magnitude of motion vector and the variance values of subband block. Because codebook is genrated considering energy distribution of each region classified by motion vector and variance of subband block, this technique gives a very good visual quality at low bit rate coding.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.5
• /
• pp.1291-1299
• /
• 1995

In confined coaxial jets, the flow-mixing characteristics depend on the initial conditions at the nozzle outlet such as velocity ratio and nozzle radius ratio. In this study, nozzle ratio(inner/outer) was 0.3. Longitudinal axial velocity, turbulent intensity and Reynolds shear stress were measured by CTA. Measurements were made from the duct inlet to the region where similarity solution could exist. This study investigated flow charicteristics according to the variation of similitude parameter which was derived from the theory of Craya-Cutet. The range of similarity region depends on the variation of the similitude patameter. The form factor obtained from the axial velocity profile in the similarity region was constant. The higher the similitude parameter, the wider the spread rate of the jets. Due to this fact, the similarity conditions developed more quickly and the region where the similarity holds became narrow. Present experimental data confirmed the validity of Craya-Curtet theory.