• Journal of the Korean Vacuum Society
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• v.21 no.6
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• pp.333-341
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• 2012

Indium Tin Oxide (ITO) thin films were prepared by RF magnetron sputtering with different flow rates of $O_2$ gas from 0 to 12 sccm. Electrical and optical properties of these films were characterized and analyzed. ITO deposited on soda lime glass and RF power was 2 kW, frequency was 13.56 MHz, and working pressure was $1.0{\times}10^{-3}$ Torr, Ar gas was fixed at 1,000 sccm. The transmittance was measured at 300~1,100 nm ranges by using Photovoltaic analysis system. Electrical properties were measured by Hall measurement system. ITO thin films surface were measured by Scanning electron microscope. Atomic force microscope surface roughness scan for ITO thin films. ITO thin films secondary electron emission coefficient(${\gamma}$) was measured by ${\gamma}$-Focused ion beam. The resistivity is about $2.4{\times}10^{-4}{\Omega}{\cdot}cm$ and the weighted average transmittance is about 84.93% at 3 sccm oxygen flow rate. Also, we investigated Work-function of ITO thin films by using Auger neutralization mechanism according to secondary electron emission coefficient(${\gamma}$) values. We confirmed secondary electron emission peak at 3 sccm oxygen flow rate.

• Journal of Life Science
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• v.14 no.4
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• pp.670-675
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• 2004

We have examined the effects of S-nitroso-N-acetylpenicillamine (SNAP), prostaglandin $E_2$ (PG $E_2$) and dibutric cyclic AMP (dbcAMP) on the methylation of interferon- ${\gamma}$ (IFN- ${\gamma}$ ) gene in human Jurkat T cells. The CpG dinucleotide which is critical for promoter function of IFN- ${\gamma}$ gene was methylated by treatment with SNAP, PG $E_2$ and dbcAMP, respectively. The DNA methylation induced by PG $E_2$ was suppressed by the addition of 2',5'-dideoxyadenosine (DDA), an inhibitor of adenylyl cyclase, but the suppression was not observed in SNAP treated cells. The NO production was not enhanced in PG $E_2$ or dbcAMP treated cells. The methylation induced by PG $E_2$ and dbcAMP was not suppressed by the addition of $N^{G}$-methyl-L-arginine (L-NMMA), NO synthase inhibitor. In conclusion, the inhibition of INF- ${\gamma}$ gene expression by PG $E_2$ was associated with the methylation of INF- ${\gamma}$ gene by elevation of intracellular cAMP in human Jurkat T cells. However, the methylation induced by PG $E_2$ might not be mediated through the NO production.rough the NO production.

• Applied Microscopy
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• v.37 no.3
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• pp.157-166
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• 2007

This experiment was performed to evaluate the ultrastructural responses of the absorptive cells in the appendix of the mouse, inoculated with Ehrlich carcinoma cells in the inguinal area, following administration of BCG (Bacillus Calmette-Guerin). Healthy adult ICR mice weighing 25 gm each were divided into normal and experimental groups (experimental control group and BCG treated group). In the experimental groups, each mouse was inoculated with $1{\time}10^7$ Ehrlich carcinoma cells subcutaneously in the inguinal area. From next day after inoculations, 0.5mL of saline or BCG (0.5 mL/25gm B.W.: $0.03{\times}10^8{\sim}0.32{\times}10^8CFU$) were injected subcutaneously to the animals every other day. The day following the last injection, each mouse was sacrificed. Pieces of the tissue were taken from the appendix, prefixed with 2.5% glutaraldehyde-1.5% paraformaldehyde solution, followed by post-fixation with 1% osmium tetroxide solution. The ultrathin sections were stained with uranyl acetate and lead citrate. In the normal control, experimental control and BCG treated mice, general morphology of the absorptive cells of appendix were similar. But myelin figures and intramitochondrial dense granules were more frequently observed in the absorptive cells of BCG treated mice than normal control ones. Above results show that BCG did show slight ultrastructural alterations in the absorptive cell of the appendix. These results that BCG may slightly suppress function of the absorptive cells of the appendix.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.4
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• pp.317-326
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• 2013

This study was to compare the cumulative survival rate of implant-supported fixed prostheses and to analyze association between risk factors and cumulative survival rate of implant-supported fixed prostheses. In order to assess the clinical status of implant-supported fixed prostheses, individuals who treated in the Department of Prosthodontics, Pusan National University Dental Hospital, between 2000 to 2007 were examined. The results of this study were as follows: 1. Length of service of implant-supported fixed prostheses was $6.6{\pm}32.0$ years (mean), 11.7 years (median). 2. Age and sex of patient was found to have no statistically significant influence on longevity of implant-supported fixed prostheses (P>.05). 3. Reason of tooth extraction wax found to have statistically significant influence on implant-supported fixed prostheses (P<.05). The longevity of fixed prostheses was low in tooth extraction case due to periodontal disease (median:9.0 years). 4. Location of implant-supported fixed prostheses was found to have statistically significant influence on longevity of fixed prostheses (P<.05). The longevity of fixed prostheses was low in molar region (median:8.8 years). 5. Number of units in implant-supported fixed prostheses was found to have no statistically significant influence on longevity of fixed prostheses (P>.05). 6. Condition of opposing dentition was found to have no statistically significant influence on longevity of implant-supported fixed prostheses (P>.05). 7. Food impaction (40.5%), porcelain fracture (25.8%), screw loosening (23.6%) were frequent complications.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.1
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• pp.55-60
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• 2010

Purpose: The shrinkage of dental resin cement may cause several clinical problems such as distortion that may jeopardize the accurate fit to the prepared tooth and internal stress within the restorations. It is important to know the polymerization shrinkage-strain of dental resin cement to reduce clinical complications. The purpose of this study was to investigate the polymerization shrinkage-strain kinetics of six commercially available dental resin cements. Material and methods: Three self-cure resin cements (Fujicem, Superbond, M-bond) and three dual-cure resin cements (Maxcem, Panavia-F, Variolink II) were investigated. Time dependent polymerization shrinkage-strain kinetics of the materials were measured by the Bonded-disk method as a function of time at $23^{\circ}C$, with values particularly noted at 1, 5, 10, 30, 60, 120 min after mixing. Five recordings were taken for each materials. The data were analyzed with one-way ANOVA and Scheffe post hoc test at the significance level of 0.05. Results: Polymerization shrinkage-strain values were 3.72%, 4.19%, 4.13%, 2.44%, 7.57%, 2.90% for Fujicem, Maxcem, M bond, Panavia F, Superbond, Variolink II, respectively at 120 minutes after the start of mixing. Panavia F exhibited maximum polymerization shrinkage-strain values, but Superbond showed minimum polymerization shrinkage-strain values among the investigated materials (P < .05). There was no significant differences of shrinkage-strain value between Maxcem and M bond at 120 minutes after the start of mixing (P > .05). Most shrinkage of the resin cement materials investigated occurred in the first 30 minutes after the start of mixing. Conclusion: The onset of polymerization shrinkage of self-cure resin cements was slower than that of dual-cure resin cements after mixing, but the net shrinkage strain values of self-cure resin cements was higher than that of dual-cure resin cements at 120 minutes after mixing. Most shrinkage of the dental resin cements occurred in the first 30 minutes after mixing.

• Journal of Environmental Policy
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• v.7 no.4
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• pp.35-55
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• 2008

Assessing vulnerability to climate change is the first step to take when setting up appropriate adaptation strategies. Adaptive capacity to climate change is the important factor comprising vulnerability. An adaptive capacity index in agricultural water management system was developed considering agricultural water supply and demand for rice production in Jeolla-do, Korea. The agricultural water supply was assumed to be equal to the amount of water stored in the major agricultural reservoirs, while data on the agricultural water demand was obtained from the dynamic simulation results by Korea Agriculture Corporation(KAC). The spatial unit for analysis was conducted at the county(Si, Gun, Gu) level and temporal scale was based on every month from 1991-2003. Adaptive capacity for drought stress index(ACDS index) was calculated as the percentage of data points where the irrigated water supply was greater than the crop water demand. The ACDS index was compared with SWSCI(Standard Water Storage Capacity Index) and the relationship showed high degree of fit($R^2$=0.84) using the exponential function, indicating that the developed ACDS index is useful for evaluating the status of the balance between agricultural water supply and demand, especially for the small sized agricultural reservoirs. This study provided the methodological basis for developing climate change vulnerability index in agricultural water system which is projected to be more frequently exposed to drought condition in the future due to climate change. Further research should be extended to the study on the water demand of the crops other than rice and to the projection of the change in ACDS index in the future.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.2
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• pp.109-120
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• 2017

A discounted cost model for preventive maintenance of armor units of rubble-mound breakwaters is mathematically derived by combining the deterioration model based on a discrete-time stochastic process of shock occurrence with the cost model of renewal process together. The discounted cost model of condition-based maintenance proposed in this paper can take into account the nonlinearity of cumulative damage process as well as the discounting effect of cost. By comparing the present results with the previous other results, the verification is carried out satisfactorily. In addition, it is known from the sensitivity analysis on variables related to the model that the more often preventive maintenance should be implemented, the more crucial the level of importance of system is. However, the tendency is shown in reverse as the interest rate is increased. Meanwhile, the present model has been applied to the armor units of rubble-mound breakwaters. The parameters of damage intensity function have been estimated through the time-dependent prediction of the expected cumulative damage level obtained from the sample path method. In particular, it is confirmed that the shock occurrences can be considered to be a discrete-time stochastic process by investigating the effects of uncertainty of the shock occurrences on the expected cumulative damage level with homogeneous Poisson process and doubly stochastic Poisson process that are the continuous-time stochastic processes. It can be also seen that the stochastic process of cumulative damage would depend directly on the design conditions, thus the preventive maintenance would be varied due to those. Finally, the optimal periods and scale for the preventive maintenance of armor units of rubble-mound breakwaters can be quantitatively determined with the failure limits, the levels of importance of structure, and the interest rates.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.4
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• pp.341-348
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• 2010

The basic principle of fry drying process of sludge lies in the rapid pressure change of sludge material caused by the change of temperature between oil and moisture due to the difference of specific heat. Therefore, the rapid increase of pressure in drying sludge induces the efficient moisture escape through sludge pores toward heating oil media. The object of this study is to carry out a systematic investigation of the influence of various parameters associated with the sludge fry drying processes on the drying efficiency. To this end, a series of parametric experimental investigation has been made together with the numerical calculation in order to obtain typical drying curves as function of important parameters such as drying temperature, sludge diameter, oil type and sludge type. In the aspect of frying temperature, especially it is found that the operation higher than $140^{\circ}C$ was favorable in drying efficiency regardless of type of waste oil employed in this study. The same result was also noted consistently in the investigation of numerical calculation, that is, in that the sludge particle drying was efficiently made over $140^{\circ}C$ irrespective of the change of particle diameter. As expected, in general, the decrease of diameter in sludge was found efficient both experiment and numerical calculation in drying due to the increased surface area per unit volume. In the investigation of oil type and property, the effect of the viscosity of waste oil was found to be more influential in drying performance. In particular, when the oil with high viscosity, a visible time delay was noticed in moisture evaporation especially in the early stage of drying. However, the effect of high viscosity decreased significantly over the temperature of $140^{\circ}C$. There was no visible difference observed in the study of sludge type but the sewage sludge with a slightly better efficiency. The numerical study is considered to be a quite useful tool to assist in experiment with more detailed empirical modeling as further work.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.293-296
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• 2002

UP Link is One of the commercial product which converts HTML to HDML convertor in order to show the internet www contents in the mobile environments. When UP browser accesses HTML pages, the agent in the UP Link controls the converter to change the HTML to the HDML, I-Mode, which is developed by NTT-Docomo of Japan, has many contents through the long and stable commercial service. Micro Explorer, which is developed by Stinger project, also has many additional function. In this paper, we designed and implemented WAP convertor which can accept C-HTML contents and mHTML contents. C-HTML format by I-Mode is a subset of HTML format, mHTML format by ME is similar to C-HTML, So the content provides can easily develop C-HTML contents compared with WAP and the other case. Since C-HTML, mHTML and WML are used under the mobile environment, the limited transmission capacity of one page is also similar. In order to make a match table. After that, we apply conversion algorithm on it. If we can not find matched element, we arrange some tags which only can be supported by WML to display in the best shape. By the result, we can convert over 90% contents.

• Korean Journal of Poultry Science
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• v.42 no.3
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• pp.223-230
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• 2015

Eggs are an important source of protein for the human diet. Consumers want fresher, more delicious and more sanitary eggs. In Korea, the Shell Egg Grading system (EGS) was employed in 2001. The portion of graded shell eggs has increased every year, but graded shell eggs account for only 6% of all eggs. The EGS should satisfy producers, distributors and consumers. However, the EGS does not have an official function because of many problems. Consumers cannot select various graded shell eggs in the market, and producers do not receive enough profit even though they produce top-quality graded shell eggs. There are few studies on the EGS, Therefore, this study was performed to improve the EGS. We surveyed the EGS, GP Centers and farmers. Large companies (farmers) are more satisfied than small companies with the EGS. There was a high tendency for the companies (farmers) that are not involved with the EGS to think that graded and ungraded shell eggs are similar, in contrast to the companies (farmers) connected to the EGS. We should have to change the grading system of grade shell eggs, establish of the cold chain system, change of the law for the school meals, minimize payment for the grading shell eggs for developing EGS. Based on this study, the egg industry can benefit through the improvement of the EGS.