• Korean Journal of Veterinary Research
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• v.16 no.1
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• pp.11-25
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• 1976

Studies on pathogenicities and developmental stages of Nosema apis (Zander, 1909) were carried out through artificial infection to Nosema free honey bees with various levels of spores isolated from local honey bee colony. The results obtained were summarized as follows: 1. The clinical symptoms were observed as dysentery, enteritis of mid-gut (enlargement and decoloration), crawling posture and shortening of the longevity of worker bees in the rearing honey bee colony inoculated with the spores. 2. Number of spores harvested from laboratory rearing honey bees were progresively increased to 4 weeks after inoculation. The regression equations and coefficients of correlations to various spore levels were as follows in each treatment colony. Colony 1. ($$1,000{\times}10^4spores/ml$$) $$y_{c1}=471{\times}10^{4}x+454{\times}10^4(r=0.65^*$$) Colony 2. ($$500{\times}10^4spores/ml$$) $$y_{c2}=340{\times}10^{4}x+207.8{\times}10^4(r=0.99^{**}$$) Colony 3. ($$100{\times}10^4spores/ml$$) $$y_{c3}=150{\times}10^{4}x+84.2{\times}10^4(r=0.99^{**}$$) Colony 4. ($$10{\times}10^4spores/ml$$) $$y_{c4}=13.8{\times}10^{4}x+13{\times}10^4(r=0.98^{**}$$) 3. Average longevity of worker bees artificially infected with Nosema apis was shortened as 21.7~43.8% compare to the control. (p<.05, p<.01) 4. The spores which were isolated from honey bee colony infected with Nosema disease were ovoid or spherical form, and measured, as a rule, from $4.7{\mu}m$ to $6.1{\mu}m$ (mean $5.3{\mu}m$) in length and from $2.4{\mu}m$ to $3.2{\mu}m$ (mean $2.9{\mu}m$) in width. 5. In the mid-gut of honey bees, the spore was progresively germinated and became trophozoite stage. The trophozoites were grown to meronts and their binary fission were begun. The divided two sporoblasts were developed to the spores which had elastic membrane. The new spores were shed in excreta of honey bees 10~15 day after inoculation at $25{\pm}2$ centigrade. 6. The ultrastructure of spore membrane consisted of three layers, such as, outer, middle and inner layer. The sporoplasm consisting lamellar structure occupied only anterior part of the spore and was often extended to posterior direction where definite vacuoles and a polar filament was able to detect.

• Membrane Journal
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• v.15 no.2
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• pp.147-156
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• 2005

It is well-known that polyethersulfone (PES) has high $CO_2$ selectivity over $N_2\;(or\;CH_4)$ and excellent pressure resistance of $CO_2$ plasticization among muy commercialized engineering plastics[1-4]. Asymmetric PES hollow fiber membranes for flue gas separation were developed by dry-wet spinning technique. The dope solution consists of PES, NMP and acetone. Water and water/NMP mixtures are used in outer and inner coagulants, respectively. Gas permeation rate (i.e., permeance) and $CO_2/N_2$ selectivity were measured with pure gas, respectively and the micro-structure of hollow fiber membranes was characterized by scanning electron microscopy. The effects of polymer concentration, ratio of NMP to acetone, length of air gap, evaporation condition and silicone coating were investigated on the $CO_2/N_2$ separation properties of the hollow fibers. Optimized PES hollow fiber membranes exhibited high permeance of $25\~50$ GPU and $CO_2/N_2$ selectivity of $30\~40$ at room temperature and have the apparent skin layer thickness of about $0.1\;{\mu}m$. The developed PES hollow fiber membranes, would be a good candidate suitable for the flue gas separation process.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.33.1-33.7
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• 2019

Background: The concept of the ideal morphology for the alveolar bone form is an important element to reconstruct or restore the in maximizing esthetic profile and functional alveolar bone restoration. The purpose of this preliminary study is to evaluate the normal alveolar bone structure to provide the standard reference and guide template for use in diagnosing for implant placement, determining the correct amount of bone augmentation in actual clinical practice and producing prostheses based on three-dimensional imaging assessment of alveolar bone. Methods: This study was included 11 men and 11 women (average age, 22.6 and 24.5 years, respectively) selected from among 127 patients. The horizontal widths of alveolar bone of maxilla and mandible were measured at the crestal, mid-root, and root apex level on MDCT (multi-detector computed tomography) images reconstructed by medical imaging software. In addition, tooth dimensions of the central incisors, canines, second premolars, and first molars of maxilla and mandible, including the horizontal width of the interdental alveolar bone crest, were also measured and statistically analyzed. Results: The horizontal alveolar bone width of the palatal side of maxilla showed a distinct increment from the alveolar bone crest to the apical region in both anterior and posterior areas. The average widths of the maxillary alveolar ridge were as follows: central incisor, 7.43 mm; canine, 8.91 mm; second premolar, 9.57 mm; and first molar, 12.38 mm. The average widths of the mandibular alveolar ridge were as follows: central incisor, 6.21 mm; canine, 8.55 mm; second premolar, 8.45 mm; and first molar, 10.02 mm. In the buccal side, the alveolar bone width was not increased from the crest to the apical region. The horizontal alveolar bone width of an apical and mandibular border region was thinner than at the mid-root level. Conclusions: The results of the preliminary study are useful as a clinical guideline when determining dental implant diameter and position. And also, these measurements can also be useful during the production of prefabricated membranes and customized alveolar bone scaffolds.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.2
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• pp.227-238
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• 2006

Line density index(LDI) was developed to quantify a densely isothermal line rate as standard index in the ocean environment. Theoretical background on the LDI development process restricting index range 0 to 100 was described. And validation test was done for the LDI application condition that total line length is not greater than 1/10 of unit area. NOAA SST(Sea Surface Temperature) data were used for the experimental application of LDI in the South Sea of Korea. Using GIS, $0.1^{\circ}C$ isothermal lines were linearized as vector data form SST raster data, and unit area were built as polygon data. For the LDI calculation, spatial overlapping(line in polygon) was implemented. To analyze the effect of unit area size for the LDI distribution, two cases of unit area size were designed and descriptive statistics was calculated including performing normality test. The results showed no change of LDI's essential characteristics such as mean and normality except for the range of value, variance and standard deviation. Accordingly, it was found that complex structure of thermal front and even smaller scale of front width than unit area size could influence on the LDI distribution. Also, correlation analysis performed between LDI and difference of temperature(${\Delta}T^{\circ}C$), and horizontal thermal gradient(${\Delta}T^{\circ}C/km$) on the front was obtained from linear regression model. This obtained value was compared with the results from previous researches. Newly developed LDI can be used to compare the thermal front regions changing spatio-temporally in the ocean environment using absolute index value. It is considered to be significant to analyze the relationship between thermal front and marine environment or front and marine organisms in a quantitative approach described in this study.

• Journal of Aquaculture
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• v.18 no.3
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• pp.142-146
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• 2005

In this study, the reattachment processes of small and medium size of spot of Mytilus coruscus and M. edulis were observed. The small spats (Shell length, SH, $3{\sim}7mm$) of hard shelled mussel, M. coruscus showed 100% reattachment rate within 7 minutes after the detachment of byssus thread and 100% survival rate. While large spats (SH 25 mm) showed 85% reattachment rate within 5 hours and 100% survival rate for 24 hours. The reattachment rate of M. edulis (SH 30 mm) was higher than that of M. coruscus (SH, 28 mm). The thread consisted of three identifiable structures; adhesive disc, adhesive thread and adhesive root. The adhesive disk and adhesive thread of M. coruscus were larger and thicker than those of M. edulis, whereas the thickness of adhesive root was the other way round. Further studies are required to identify the relationship between the structure of byssus thread and attachment ability. This study suggests that the sizes of spats could be an important factor in determining the timing of removing and reattaching mussel seedling for aquaculture or releasing to the sea.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.10
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• pp.109-117
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• 2004

In this paper, a K-band local oscillator composed of a VCDRO(Voltage Controlled Dielectric Resonator Oscillator), GaAs MESFET, and Reflector type frequency doubler has been designed and fabricated. TO obtain a good phase noise performance of a VCDRO, a active device was selected with a low noise figure and a low flicker noise MESFET and a dielectric resonator was used for selecting stable and high oscillation frequency. Especially, to have a higher conversion gain than a conventional doubler as well as a good harmonic suppression performance with circuit size reduced a doubler structure was employed as the Reflector type composed of a reflector and a open stub of quarter wave length for rejecting the unwanted harmonics. The measured results of fabricated oscillator show that the output power was 5.8 dBm at center frequency 12.05 GHz and harmonic suppression -37.98 dBc, Phase noise -114 dBc at 100 KHz offset frequency, respectively, and measured results show of fabricated frequency doubler, the output power at 5.8 dBm of input power is 1.755 dBm conversion gain 1.482 dB, harmonic suppression -33.09 dBc, phase noise -98.23 dBc at 100 KHz offset frequency, respectively. This oscillator could be available to a local oscillator in K-band which used frequency doubler techniques.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.6
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• pp.683-689
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• 2006

Statement of problem. Interfacial toughness is important in the mechanical property of layered dental ceramics such as core-veneered all-ceramic dental materials. The interfaces between adjacent layers must be strongly bonded to prevent delamination, however the weak interface makes delamination by the growth of lateral cracks along the interface. Purpose. The purpose of this study was to determine the effect of the reaction layer on the interfacial fracture toughness of the core/veneer structure according to the five different divesting. Materials and methods. Thirty five heat-pressed Lithia-based ceramic core bars (IPS Empress 2), $20mm{\times}3mm{\times}2mm$ were made following the five different surface divesting conditions. G1 was no dissolution or sandblasting of the interaction layer. G2 and G3 were dissolved layer with 0.2% HF in an ultrasonic unit for 15min and 30 min. G4 and G5 were dissolved layer for 15min and 30min and then same sandblasting for 60s each. We veneered bilayered ceramic bars, $20mm{\times}2.8mm{\times}3.8mm$(2mm core and 1.8mm veneer), according to the manufacturer's instruction. After polishing the specimens through $1{\mu}m$ alumina, we induced five cracks for each of five groups within the veneer close to interface under an applied indenter load of 19.6N with a Vickers microhardness indenter. Results. The results from Vickers hardness were the percentage of delamination G1:55%, G2:50%, G3:35%, G4:0% and G5:0%. SEM examination showed that the mean thickness of the reaction layer were G1 $93.5{\pm}20.6{\mu}m$, G2 $69.9{\pm}14.3{\mu}m$, G3 $59.2{\pm}20.2{\mu}m$, G4 $0.61{\pm}1.44{\mu}m$ G5 $0{\pm}0{\mu}m$. The mean interfacial delamination crack lengths were G1 $131{\pm}54.5{\mu}m$, G2 $85.2{\pm}51.3{\mu}m$, and G3 $94.9{\pm}81.8{\mu}m$. One-way ANOVA showed that there was no statistically significant difference in interfacial crack length among G1, G2 and G3(p> 0.05). Conclusion. The investment reaction layer played important role at the interfacial toughness of body ceramic bonded to Lithia-based ceramic.

• Korean journal of communication and information
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• v.45
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• pp.7-48
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• 2009

The recent crises of Marxism do not mean Marx’s crisis. Marx said that he was not a Marxist. The purposes of this essay explore (1) the modern identity of the political economy; (2) the possibilities of mutual understanding between neoclassical economics and Marxist economics; (3) problems of the political economy in media and communication industry. I have begged for analytical Marxists, because of their good fruits. They accepted the methods of modern social science and they constituted a tremendous advance in the application of the scientific methods to the study of society. In insisting on micro-foundations(methodological individualism), analytical Marxism distinguished itself from structuralism and functionalism. I appreciate that analytical Marxism has reduced a theory to practice. But the works didn’t listen to everyone(from Marxists to un-Marxists), and explain everything. Making theory with production/consumption, macro/micro, and structure/behavior is a road to the political economy in the long run. It also applies to media and communication industry. The realm of media/communication is broad, which in philosophy, humanities, politics, economics, sociology, and engineering. And media policy is more complicated by politicians who look at the same situation from different angles. By the aid of interdisciplinary research, the political economy of media/communication shall explain at full length.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.609-615
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• 2005

$TiO_2$ particles, 30-300 nm in diameter, were prepared by thermal decomposition of titanium tetraisopropoxide (TTIP) using an aerosol microreactor, by which about $1{\mu}l$ of the liquid precursor is injected into an evaporator, 1 cc in volume, and vaporized precursor is then transported by nitrogen as a bolus to a tubular reactor 4 mm in diameter and 35 cm in length. Investigated were the effects of the reactor temperature and the concentration of TTIP vapor on the morphology, particle size distribution and crystalline structure of produced $TiO_2$ particles. With TTIP vapor concentration kept constant at 1 mol%, the reactor temperature was varied from 300 to 500 and $700^{\circ}C$. The primary particle size decreased with increasing the temperature, and the size distributions were mono-modal at 300 and $500^{\circ}C$, but bi-modal at $700^{\circ}C$. The TTIP vapor concentration was increased from 1 to 3.5 and 7 mol%, holding the reactor temperature at $700^{\circ}C$. The bi-modal distribution seen at the concentration of 1 mol% disappeared and the number of particles composing an agglomerate increased at the higher concentrations. These effects of the reactor temperature and the precursor concentration were discussed in comparison with experimental results reported earlier.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.262-275
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• 2015

The treatment of areas demanding esthetic requirements, such as maxillary anterior teeth, should take into account the achievement of a healthy, harmonious to the surrounding tissue, and an attractive smile line. In this case report, smile line, soft tissue and hard tissue morphology, and the anatomy and proportion of the tooth, must be considered. In patients with unesthetic maxillary anterior ratio due to inadequate gingival contour and diastema caused by peg lateralis, it would be challenging to achieve an esthetic restoration by orthodontic treatment alone. In such case, after orthodontic treatment, dento-gingivo-facial compositional diagnosis and analysis, followed by gingivectomy and prosthodontic restoration is needed to improve the interdental mesial/distal, width/length ratio to achieve a satisfactory esthetic result. In addition, when improving the tooth proportion of peg lateralis by prosthodontic treatment, Porcelain laminate veneer (PLV), which results in less tooth structure loss, reproduction of similar shade to that of the proximal tooth and high transparency, is recommended. This case report demonstrates esthetic improvements by prosthodontic restoration through systematic diagnosis and treatment procedure in patients with unesthetic maxillary anterior proportion after orthodontic treatment due to peg lateralis by means of two female patients aged twenty years old.