• Journal of the Korean Geotechnical Society
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• v.21 no.4
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• pp.65-70
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• 2005

Many case histories of re-liquefaction phenomena seem to support the idea that sand deposits, if they once have been liquefied, could be reliquefied again by a subsequent earthquake even though the earthquake is smaller than the previous one. The magnitude of the strains induced in the initial liquefaction has a significant influence on the resistance of the sample to re-liquefaction. The deposits undergoing liquefaction experience large shear strain during liquefaction. And this previous strain changes the microstructure into highly anisotropic structure such as columnlike structure and connected voids. This type of anisotropy is so unstable that it can reduce re-liquefaction resistance. It is blown that the extent of anisotropic structural change depends on the gradation characteristics of ground. The purpose of this study is to estimate the correlation between the gradation characteristics of the sand and the ratio of re-liquefaction resistance to liquefaction resistance. In this study, 1-g shaking table tests were carried out on five different kinds of sands. During the tests the values of excess pore pressure at various depths and surface settlements were measured. Re-liquefaction resistances were not affected by the initial void ratio and the effective confining pressures, and the deposits of all test sands which had once been liquefied were reliquefied in the cyclic loading number below 1 to 1.5. The ratio of re-liquefaction resistance to liquefaction resistance linearly decreased as $D_{10}/C_u$ increased, and was constant as about 0.2 above the value of $D_{10}/C_u$, 0.15 mm.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.203-215
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• 2007

Statement of problem: Titanium and its alloy, with their excellent bio-compatibility and above average resistance to corrosion, have been widely used in the field of dentistry. However, the excessive oxidization of titanium which occurs during the process of firing on porcelain makes the bonding of titanium and porcelain more difficult than that of the conventional metal-porcelain bonding. To solve this problem related to titanium-porcelain bonding, several methods which modify the surfaces, coat the surfaces of titanium with various pure metals and ceramics, to enable the porcelain adhesive by limiting the diffusion of oxygen and forming the adhesive oxides surfaces, have been investigated. Purpose: The purpose of this study was to know whether the titanium-porcelain bonding strength could be enhanced by treating the titanium surface with gold and TiN followed by fabrication of clinically applicable porcelain-fused-to-titanium crown Material and method: The porcelain-fused-to-titanium crown was fabricated after sandblasting the surface of the casting titanium coping with $Al_2O_3$ and treating the surface with gold and TiN coating followed by condensation and firing of ultra-low fusing porcelain. To compare with porcelain-fused-to-titanium crowns, porcelain-fused-to-gold crowns were fabricated and used as control groups. The bonding strengths of porcelain-fused-to-gold crowns and porcelain-fused-totitanium crowns were set for comparison when the porcelain was fractured on purpose to get the experimental value of fracture strength. Then, the surface were examined by SEM and each fracturing pattern were compared with each other Result:Those results are as follows. 1. The highest value of fracture strength of porcelain-fused-to-titanium crowns was in the order of group with gold coating, group with TiN coating, group with $Al_2O_3$ sandblasting. No statistically significant difference was found among the three (P>.05). 2. The porcelain-fused-to-gold crowns showed the highest value in bonding strength. The bonding strength of crowns porcelain-fused-to-titanium crowns of rest groups showed bonding strength reaching only 85%-94% of that of PFG, though simple comparision seemed unacceptable due to the difference in materials used. 3. The fracturing patterns between metal and porcelain showed mixed type of failure behavior including cohesive failure and adhesive failure as a similar patterns by examination with the naked eye and SEM. But porcelain-fused-to-gold crowns showed high incidence of adhesive failure and porcelain-fused-to-titanium crowns showed high incidence of cohesive failure. Conclusion: Above results proved that when fabricating porcelain-fused-to-titanium crowns, treating casting titanium surface with gold or TiN was able to enhance the bonding strength between titanium and porcelain. Mean value of masticatory force was found to showed clinically acceptable values in porcelain bonding strength in all three groups. However, more experimental studies and evaluations should be done in order to get better porcelain bonding strength and various surface coating methods that can be applied on titanium surface with ease.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.169-181
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• 2007

Statement of problem: Titanium is well known as a proper metal for the dental restorations, because it has an excellent biocompatibility, resistance to corrosion, and mechanical property. However, adhesion between titanium and dental porcelains is related to the diffusion of oxygen to the reaction layers formed on cast-titanium surfaces during porcelain firing and those oxidized layers make the adhesion difficult to be formed. Many studies using mechanical, chemical and physical methods to enhance the titanium-ceramic adhesion have been actively performed. Purpose: This study meant to comparatively analyse the adhesion characteristics depending on different titanium surface coatings after coating the casts and wrought titanium surfaces with Au and TiN. Material and method: In this study, the titanium specimens (CP-Ti, Grade 2, Kobe still Co. Japan) were categorized into cast and wrought titanium. The wrought titanium was cast by using the MgO-based investment(Selevest CB, Selec). The cast and wrought titanium were treated with Au coating($ParaOne^{(R)}$., Gold Ion Sputter, Model PS-1200) and TiN coating(ATEC system, Korea) and the ultra low fusing dental porcelain was fused and fired onto the samples. Biaxial flection test was done on the fired samples and the porcelain was separated. The adhesion characteristics of porcelain and titanium after firing and the specimen surfaces before and after the porcelain fracture test were observed with SEM. The atomic percent of Si on all sample surfaces was comparatively analysed by EDS. In addition, the constituents of specimen surface layers after the porcelain fracture and the formed compound were evaluated by X-ray diffraction diagnosis. Result: The results of this study were obtained as follows : 1. The surface characteristics of cast and wrought titanium after surface treatment(Au, TiN, $Al_2O_3$ sandblasting) were similar and each cast and wrought titanium showed similar bonding characteristics. 2. Before and after the biaxial flection test, the highest atomic weight change of Si component was found in $Al_2O_3$ sandblasted wrought titanium(28.6at.% $\rightarrow$ 8.3at.%). On the other hand, the least change was seen in Au-Pd-In alloy(24.5at.% $\rightarrow$ 9.1at.%). 3. Much amount of Si components was uniformly distributed in Au and TiN coated titanium, but less amount of Si's was unevenly dispersed on Al2O3 sandblasting surfaces. 4. In X-ray diffraction diagnosis after porcelain debonding, we could see $Au_2Ti$ compound and TiN coating layers on Au and TiN coated surfaces and $TiO_2$, typical oxide of titanium, on all titanium surfaces. 5. Debonding of porcelain on cast and wrought titanium surface after the biaxial flection is considered as a result of adhesion deterioration between coating layers and titanium surfaces. We found that there are both adhesive failure and cohesive failure at the same time. Conclusion: These results showed that the titanium-ceramic adhesion could be improved by coating cast and wrought titanium surfaces with Au and TiN when making porcelain fused to metal crowns. In order to use porcelain fused to titanium clinically, it is considered that coating technique to enhance the bonding strength between coating kKlayers and titanium surfaces should be developed first.

• Tuberculosis and Respiratory Diseases
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• v.56 no.5
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• pp.505-513
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• 2004

Background : In lung cancer patients, the presence of metastatic neck nodes is a crucial indicator of inoperabilty. So thorough physical examination of neck is always mandatory, but sometimes those are hardly palpable even by the skillful hand. Ultrasonography is a useful diagnostic method in detection of small impalpable lymph nodes and in guidance of fine needle aspiration biopsy. In this study we evaluated the clinical usefulness of ultrasonography(USG) and ultrasound-guided fine needle aspiration cytology(US-FNA) in lung cancer patients without palpable neck nodes. Methods and Materials : From Sep 2002 to Sep 2003, 36 non-small cell lung cancer patients (20 adenocarcinoma, 16 squamous cell cancer) and 10 small cell lung cancer patients without palpable neck nodes on physical examiation were enrolled. patients who had contralateral mediastinal nodal enlargement(>1cm) on chest CT were excluded. After the routine check of USG on the neck, US-FNA was done in cases with enlarged neck nodes (${\geq}5mm$ in the short axis). The presence of enlarged lymph node on USG, and of malignant cells on cytology were evaluated by the histological type and the patients' clinical stage of lung cancer. Results : Among 36 non-small lung cell cancer patients, 14 (38.8%) had enlarged neck nodes on USG, and 5 of 10 small cell lung carcinoma patients. The mean diameter of the neck nodes was 9.8 mm (range, 7-12 mm). US-FNA of 14 non-small cell lung cancer patients revealed tumor cells in eight patients (57.1%). In 5 small cell lung cancer pateints, tumor cells were found in all cases. By the result of US-FNA, the clinical stage of 8 out of 36 (22.2%) non-small cell lung cancer patients had changed, including two cases of shift from the operable IIIa to the inoperable IIIb. In small cell lung cancer patients their clinical stage was not changed after US-FNA, but their pathological diagnosis was easily done in two cases, in whom endobronchial lesions were not found on bronchoscopy. Conclusions : USG and US-FNA of neck node seem to be safe, sensitive and cost-effective diagnostic tools in the evaluation of lung cancer patients without palpable neck nodes.

• Tuberculosis and Respiratory Diseases
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• v.83 no.1
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• pp.31-41
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• 2020

Background: Chronic cough is defined as a cough lasting more than 8 weeks and socio-economic burden of chronic cough is enormous. The characteristics of chronic cough in Korea are not well understood. The Korean Academy of Tuberculosis and Respiratory Diseases (KATRD) published guidelines on cough management in 2014. The current study evaluated the clinical characteristics of chronic cough in Korea and the efficacy of the KATRD guidelines. Methods: This was a multi-center, retrospective observational study conducted in Korea. The participants were over 18 years of age. They had coughs lasting more than 8 weeks. Subjects with current pulmonary diseases, smokers, exsmokers with more than 10 pack-years or who quit within the past 1 year, pregnant women, and users of cough-inducing medications were excluded. Evaluation and management of cough followed the KATRD cough-management guidelines. Results: Participants with chronic cough in Korea showed age in the late forties and cough duration of more than 1 year. Upper airway cough syndrome was the most common cause of cough, followed by cough-variant asthma (CVA). Gastro-esophageal reflux diseases and eosinophilic bronchitis were less frequently observed. Following the KATRD cough-management guidelines, 91.2% of the subjects improved after 4 weeks of treatment. Responders were younger, had a longer duration of cough, and an initial impression of CVA. In univariate and multivariate analyses, an initial impression of CVA was the only factor related to better treatment response. Conclusion: The causes of chronic cough in Korea differed from those reported in other countries. The current Korean guidelines proved efficient for treating Korean patients with chronic cough.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.10
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• pp.1406-1413
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• 2009

In order to investigate the quality characteristics of candies prepared with Compositae species flower extracts, the samples of Chrysanthemum indicum Linne (CI), C. boreale Makino (CB), and C. zawadskii var. latilobum (Maxim.) Kitam (CZ) were extracted with hot water and concentrated, and then added with various concentrations of 5$\sim$20% for candy preparation. L-value of candy color was decreased, but a- and b-value were increased with increasing amount of added extracts. pH was decreased, but total acidity was increased with increasing amount of added extracts. Moisture content of CI, CB, and CZ candies were 2.61$\sim$4.11, 2.46$\sim$4.57, and 2.27$\sim$4.43%, respectively. Hardness of candies were decreased with increasing amount of added extracts. CZ candy of 20% added extract showed the highest total polyphenol, flavonoid content, electron donating ability and anol, flavonaid content at 2.71 mg/g, 0.86 mg/g, 76.24%, and 3.17 mg AA eq/g, respectively. In sensory evaluation, the CI and CZ candies of 10% added extract obtained higher sensory scores.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.39-44
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• 2011

This study was carried out to examine microbiological contamination of ready-to-eat products and to propose a draft-standard and specifications according to food types. RTE foods were classified into 6 groups including fish products, meat products, breads, rices, salads, and fresh cut foods. The prevalence rates of pathogens detected from all samples were compared among food categories. The pH ranges for all RTE samples were between 3.8 and 7.3. Total aerobic cell counts ranged from 2 to 6 log CFU/g. Bread, rice and fresh-cut foods showed significantly higher counts, which ranged above 4.0 log CFU/g among the samples. Two kinds of rice were above the level of the KFDA Food Code standard for Eschrichia coli. The prevalence rate of E. coli in the rice was 6.7%. For Staphylococcus aureus, one fish product and one bread-product had levels above 2 log CFU/g. Bacillus cereus counts for all samples were below the level of 3 log CFU/g. Listeria monocytogenes was not detected in the samples. Therefore, these data suggest that the primary microbial hazard factors for ready-to-eat foods and risk assessments should focus on E. coli, S. aureus, and B. cereus.

• Journal of Internet Computing and Services
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• v.17 no.1
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• pp.101-107
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• 2016

Due to the recent advancement in digital imaging technology, development of intervention equipment has become generalize. Video arbitration procedure is a process to insert a tiny catheter and a guide wire in the body, so in order to enhance the effectiveness and safety of this treatment, the high-quality of x-ray of image should be used. However, the increasing of radiation has become the problem. Therefore, the studies to improve the performance of x-ray detectors are being actively processed. Moreover, this intervention is based on the reference of the angiographic imaging and 3D medical image processing. In this paper, we propose a guidance system to support this intervention. Through this intervention, it can solve the problem of the existing 2D medical images based vessel that has a formation of cerebrovascular disease, and guide the real-time tracking and optimal route to the target lesion by intervention catheter and guide wire tool. As a result, the system was completely composed for medical image acquisition unit and image processing unit as well as a display device. The experimental environment, guide services which are provided by the proposed system Brain Phantom (complete intracranial model with aneurysms, ref H+N-S-A-010) was taken with x-ray and testing. To generate a reference image based on the Laplacian algorithm for the image processing which derived from the cerebral blood vessel model was applied to DICOM by Volume ray casting technique. $A^*$ algorithm was used to provide the catheter with a guide wire tracking path. Finally, the result does show the location of the catheter and guide wire providing in the proposed system especially, it is expected to provide a useful guide for future intervention service.

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.412-419
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• 2012

This study assessed the impacts of land use types on water quality in the tributary of the Yeongsan river basin. Temporal changes in water quality parameters (BOD, COD, TOC, T-P, T-N, SS) were investigated. 13 water sampling sites were selected; they were then collected and analyzed according to the standard method. The results showed that water quality parameters of the study sites ranged as follows : BOD, from 0.3 to $21.9mg\;L^{-1}$ (mean $3.3mg\;L^{-1}$); COD, from 1.0 to $38.0mg\;L^{-1}$ ($6.4mg\;L^{-1}$); TOC, from 0.6 to $20.0mg\;L^{-1}$ ($4.5mg\;L^{-1}$); T-P, from 0.009 to $1.973mg\;L^{-1}$ ($0.144mg\;L^{-1}$); T-N, from 0.6 to $17.1mg\;L^{-1}$ (mean $3.5mg\;L^{-1}$); SS, from 0.3 to $292.0mg\;L^{-1}$ ($20.3mg\;L^{-1}$). Generally, the paddy and upland dominated region had high concentrations of water quality parameters, whereas the forest dominated region had low concentrations. In addition, water quality parameters were positively correlated with paddy and upland, whereas the parameters were negatively correlated with forest. The result implies that paddy and upland are the dominant factors leading to stream pollution in the study sites, while a higher percentage of forest area contributes to improved water quality. Therefore, it is important to manage paddy and upland in order achieve efficient management of water quality.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.797-808
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• 2016

The experiment of grape leafroller (Herpetogramma luctuosalis) was carried out at Okcheon area from 2007 to 2009 and 2015. The grape leafroller had been occurred at a campbell early' organic vineyard in Okcheon. It's larva was rolling the leaf of grape and ate the leaf. So the leaf of grape decreased. In organic vineyards, adult grape leafroller' generation rate per year showed the first peak in mid-June, the second peak in early -August and the third in mid-September. The larva showed the first peak in early July and the second peak in late August-early September. The grape leaf roller had three generations per year. And it took $60.9{\pm}1.09days$ from egg to adult in growth chamber (VS-91G09M-1300) which the relative humidity conditions was $60{\pm}10%$, temperature $25{\pm}2^{\circ}C$ and photoperiod 16L:8D (The egg : $12{\pm}0days$, larvae : $22.2{\pm}0.22days$, pupa : $10.6{\pm}0.75days$ and adult : $16.1{\pm}0.45days$). It was conducted to find out the effect of microbial pesticide treatments to control H. luctuosalis. The 4 microbial pesticides (Bacillus thurigiensis) were treated twice on the grape leaves in June 11 and 21 at an organic vineyard in Okcheon. On 10 days after last treatment, the control value of all microbial pesticides were more than 95%. When the dates of spraying to the grape leaves were on May 22, June 12 and July 2 each, the effects of microbial pesticide were 73.9%, 93.5% and 43.6% respectively. As a result, it was effective that Bt was sprayed to grape leaves on mid and late June for controling the H. luctuosalis in organic vineyard. And microbial pesticide Bt was thought to be useful to control the grape leafroller in organic vineyard.