• Journal of The Korean Astronomical Society
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• v.49 no.5
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• pp.225-232
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• 2016

We present an optical imaging survey of AKARI Deep Field South (ADF-S) using the Korea Microlensing Telescope Network (KMTNet), to find optical counterparts of dusty star-forming galaxies. The ADF-S is a deep far-infrared imaging survey region with AKARI covering around 12 deg², where the deep optical imaging data are not yet available. By utilizing the wide-field capability of the KMTNet telescopes (~4 deg²), we obtain optical images in B, R and I bands for three regions. The target depth of images in B, R and I bands is ~24 mag (AB) at 5σ, which enables us to detect most dusty star-forming galaxies discovered by AKARI in the ADF-S. Those optical datasets will be helpful to constrain optical spectral energy distributions as well as to identify rare types of dusty star-forming galaxies such as dust-obscured galaxy, sub-millimeter galaxy at high redshift.

• Korean Journal of Veterinary Research
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• v.41 no.2
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• pp.189-195
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• 2001

Single base substitution and deletion mutation have been introducted into the verotoxin 2 (VT2)A subunit gene from O157:H7 isolates to reduce cytotoxicity of VT2 and the cytotoxicity between wild type toxin and mutant toxoid were compared. A M13-derived recombinant plasmid pEP19RF containing a 940bp EcoRI-PstI fragment of VT2A gene was constructed for oligonucleotide-directed mutagenesis. The duoble mutant pDOEX was constructed by point and deletion mutation of two different highly conserved regions of VT2A encoding active site cleft of enzymatic domain. The key residue, Glu 167(GAA) and the pentamer(WGRIS) consisting of the enzymatic domain were replaced by ASP(GAC) and completely deleted in nucleotide sequence analysis of mutant, respectively. In the comparision of vero cell cytotoxicity between wide type toxin and toxoid from mutant, the wild type toxin expressed cytotoxicity in dilution of $10^{-6}$, but the toxid from mutant did not show cytotoxicity to vero cells.

• Atmosphere
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• v.20 no.2
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• pp.187-194
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• 2010

We estimate the economic benefit of weather modification (precipitation enhancement and fog dissipation) by assuming its operation for the considered regions. Based on the statistical data, the economic benefit of the virtually operational precipitation enhancement experiments for the Andong and Imha basins, where the natural precipitation is relatively lack in South Korea, is calculated 348 for the water resources, 22,458 for forest fire prevention, and 28,458 million won/year for the drought relief. The benefit of the fog dissipation operation for the Incheon International Airport is estimated 7,365 million won/year for the flight delay due to fog. The calculated ratio of benefit to cost for precipitation enhancement operation for the basins is 14.07, which is comparable to that conducted in other countries.

• Research in Community and Public Health Nursing
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• v.13 no.3
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• pp.493-502
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• 2002

Purpose: This study was conducted to measure the levels of Health status, perceived stress, self-esteem, and achievement motivation and assertive behavior of adolescents. The relationships among these variables as well as predictors of health status were examined. Method: The sample was composed of 496 students (male: 195. female: 301) from 3 high schools in Seoul and Kyunggi-Do regions. The instruments used in this study were as follows: health status scale developed by Noh (1991), perceived stress scale developed by Park(1996), self-esteem scale developed by Rosenberg (1965), achievement motivation scale developed by Park(1986) and assertive behavior scale developed by Kim(1982). The reliability of the five instruments were examined using Chronbachs' a that ranged from, .63 to .90 in this study. The data were analyzed with the SAS program using descriptive statistics, t-test, ANOVA, Duncan multiple comparison, Pearson correlation coefficients, and stepwise multiple regression. Results: The results were as follows: 1. The mean score .of health status was 3.1, which was higher than the median of the instrument. 2. There were significant correlations of health status with self-esteem (r=.381. p=.0001), assertive behavior (r=.503. p=.0001), and perceived stress (r=-.352. p=.0001). 3. Stepwise multiple regression analysis showed that 34% of health status was affected by the level of assertive behavior (25%), self-esteem (7%), and perceived stress (2%). Conclusion: Based on these findings, assertive behavior and self-esteem appear to be specific important areas of future research as to better understand the health status of adolescents, and to develop health status-related interventions for them.

• Journal of Periodontal and Implant Science
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• v.47 no.1
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• pp.2-12
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• 2017

The aim of this narrative review is to describe treatment options for the posterior regions of the mandible and the maxilla, comparing short implants vs. longer implants in an augmented bone. The dental literature was screened for treatment options enabling the placement of dental implants in posterior sites with a reduced vertical bone height in the maxilla and the mandible. Short dental implants have been increasingly used recently, providing a number of advantages including reduced patient morbidity, shorter treatment time, and lower costs. In the posterior maxilla, sinus elevation procedures were for long considered to be the gold standard using various bone substitute materials and rendering high implant survival rates. More recently, implants were even placed without any further use of bone substitute materials, but the long-term outcomes have yet to be documented. Vertical bone augmentation procedures in the mandible require a relatively high level of surgical skill and allow the placement of standard-length dental implants by the use of autogenous bone blocks. Both treatment options, short dental implants, and standard-length implants in combination with vertical bone augmentation procedures, appear to result in predictable outcomes in terms of implant survival rates. According to recent clinical studies comparing the therapeutic options of short implants vs. long implants in augmented bone, the use of short dental implants leads to a number of advantages for the patients and the clinician.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.3
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• pp.297-303
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• 2007

In this paper, the stroke-based text extraction algorithm for digital video is proposed. The proposed algorithm consists of four stages such as text detection, text localization, text segmentation and geometric verification. The text detection stage ascertains that a given frame in a video sequence contains text. This procedure is accomplished by morphological operations for the pixels with higher possibility of being stroke-based text, which is called as seed points. For the text localization stage, morphological operations for the edges including seed points ate adopted followed by horizontal and vortical projections. Text segmentation stage is to classify projected areas into text and background regions according to their intensity distribution. Finally, in the geometric verification stage, the segmented area are verified by using prior knowledge of video text characteristics.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.5
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• pp.554-558
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• 2007

Kimura's disease is a chronic inflammatory disorder presenting regional lymphadenopathy with painless soft tissue mass. Clinically, peripheral eosinophilia and elevated serum IgE levels are observed, and proteinuria associated with renal disease can also be present. Although its etiology is not clearly understood, it occurs predominantly in young Asian males and presents as a deep, subcutaneous mass involving salivary glands of the preauricular and submandibular regions. Spontaneous remission is very rare, and although treatments such as steroid, cytotoxic therapy and irradiation are available, chronic recurrence is very common. As such, surgical excision is regarded as the mainstay of therapy for localized lesions. Histopathologically, Kimura's disease features eosinophilic abscsesses and dense lymphoid aggregates with germinal center. Clinical differential diagnosis of Kimura's disease from other parotid diseases with accompanying lymphadenopathy is often very challenging prior to biopsy. The authors report a case of a 19-year-old male diagnosed with Kimura's disease in the parotid region who underwent surgical excision and was followed up for 6 years, along with a review of related literature.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.4
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• pp.113-118
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• 2019

In this study, we investigated the growth of single-crystallinity α-Ga₂O₃ thin films on c-plane sapphire substrates using halide vapor pressure epitaxy. We also found the optimal growth conditions to suppress the phase transition of α-Ga₂O₃. Our results confirmed that the growth temperature and partial pressure of the reactive gas greatly influenced the crystallinity. The optimal growth temperature range was about 460~510℃, and the α-Ga₂O₃ thin films with the highest crystallinity were obtained at a III/VI ratio of 4. The thickness and surface morphology of the thin films was observed by scanning electron microscopy. The film thickness was 6.938 ㎛, and the full width at half maximum of the ω-2θ scan rocking curve was as small as 178 arcsec. The optical band gap energy obtained was 5.21 eV, and the films were almost completely transparent in the near-ultraviolet and visible regions. The etch pit density was found to be as low as about 6.0 × 10⁴ cm^-2.

• Korean Journal of Materials Research
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• v.26 no.3
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• pp.154-159
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• 2016

A roll-bonding process was applied to fabricate an AA1050/AZ91/AA1050 laminate complex sheet. Two AA1050 and one AZ91 magnesium sheets of 2 mm thickness, 30 mm width and 200 mm length were stacked up after surface treatment that included degreasing and wire brushing; material was then reduced to a thickness of 3 mm by one-pass cold rolling. The laminate sheet bonded by the rolling was further reduced to 2 mm in thickness by conventional rolling. The rolling was performed at 623K without lubricant using a 2-high mill with a roll diameter of 210 mm. The rolling speed was 15.9 m/min. The AA1050/AZ91/AA1050 laminate complex sheet fabricated by roll bonding was then annealed at 373~573K for 0.5h. The microstructure of the complex sheets was revealed by electron back scatter diffraction (EBSD) measurement; the mechanical properties were investigated by tensile testing and hardness testing. The strength of the complex sheet was found to increase by 11 % and the tensile elongation decreased by 7%, compared to those values of the starting material. In addition, the hardness of the AZ91 Mg region was slightly higher than those of the AA1050 regions. Both AA1050 and AZ91 showed a typical deformation structure in which the grains were elongated in the rolling direction; however, the mis-orientation distribution of grain boundaries varied greatly between the two materials.

• Journal of the Korean GEO-environmental Society
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• v.8 no.1
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• pp.21-26
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• 2007

The strength evaluation of rocks is a very important factor in designing and constructing tunnels or underground excavation. However, it takes a lot of time and endeavor to perform the unconfined compressive strength test for practice and a number of tests are limited. In order to make up for this method, the point load strength test is suggested. Generally, the strength of a rock differs depending on its type and region. However, as people unite the Point Load Strength Indexes of various regions and types to use in practice in many cases, they find difficulty in analogizing the exact strength. The purpose of this study is suggestion of the value in construction site by analizing the relation of both unconfined compressive and point load strength in the Gyeonggi gneiss complex.