• KDI Journal of Economic Policy
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• v.27 no.2
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• pp.239-251
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• 2005

This paper investigates the effectiveness of economic policy on the stock market in Korea around foreign currency crisis and stock market opening. For this purpose, the paper applied SUR technique to a set of monthly data over the period 1982.01 to 2004.12. The study finds the following results. First, for the entire sample period, Korean stock market appears to have effectively incorporated all of the past information about fiscal policy moves. However, the paper finds an evidence that some of the past monetary actions have significant impacts upon current stock returns implying that the information about past monetary moves has been overlooked. Second, there is an evidence to suggest that, after foreign currency crisis, the macro economic policy actions may influence stock market in a different way. In particular, after foreign currency crisis, monetary policy influences stock market in a more delayed pattern while past fiscal policy moves are well incorporated into current stock returns. Third, before stock market opening to foreign investors, some of the past economic policy actions have significant effects on current stock returns. On the contrary, after stock market opening, none of the past macro economic information has significant impact upon current stock returns. The results imply that stock market opening may contribute to the active utilization of economic information for market participants in Korea.

• Resources Recycling
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• v.29 no.4
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• pp.3-14
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• 2020

Titanium sponge is industrially produced by the Kroll process. In order to understand the importance of the emerging smelting and recycling process, it is necessary to review the conventional production process of titanium. Therefore this paper provides a general overview of the conventional titanium manufacturing system mainly by the Kroll process. The Kroll process can be divided into four sub-processes as follows: (1) Chlorination of raw TiO₂ with coke, by the fluidized bed chlorination or molten salt chlorination (2) Magnesium reduction of TiCl₄ and vacuum distillation of MgCl₂ and Mg by reverse U-type or I-type with reduction-distillation integrated retorts (3) Electrolysis process of MgCl₂ by monopolar cells or multipolar cells to electrolyze into chlorine gas and Mg. (4) Crushing and melting process in which sponge titanium is crushed and then melted in a vacuum arc furnace or an electron beam furnace Although the apparatus and procedures have improved over the past 80 years, the Kroll process is the costly and time-consuming batch operation for the reduction of TiCl₄ and the separation of MgCl₂.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.2
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• pp.90-96
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• 1997

Until now the research was usually related in the fishing basket for crab charybdis japonica, concentrated one's effort to modification on the construction, shape, number of entrance of fishing basket etc.. But there's not make good used to the basically habit, shelter behavior of crab. etc., and was not fundamentally modified to the ability attracting the crab on net fishing basket. In this paper, first of all investigated to the behavior of crab in water tank and then two types modification fishing baskets could the increasing to ability attracting of crab on fishing basket were designed from the result obtained in this experiment and compared with modificated net fishing basket by Kim.Go(1987.1990) at a field and tank experiment. The results obtained are summarized as follows : 1. Being the fishing baskets had dropped in the tank bottom, the touched rate and reacted rate of crab according the elapsed time agree with to experiment of Kim.Go(1987.1990)in the mainly. however, in case of plate type tangle net, the touched rate of crab increased for a short time and then decreased and the reacted rate increased in a hurry to show a maximum and then was established. 2. The beginning catch time of crab was shortest in the plate type tangle net than the any fishing baskets because it's immediately entangled if the crab was touched only a part of body on net and latest in the net fishing basket. 3. A distance of between the touched rate and the reacted rate curve were the most short, wide in the plate type tangle net. therefore, the ability attracting of crab was excellent than the any fishing baskets and in case of pipe type fishing baskets, between the 150mm and 250mm seemed not difference and showed a tendency to increasing against the net fishing baskets. 4. Pipe type fishing baskets seemed to become a good shelting place for the crab because it showed a tendency to stagnate at the inside in that. 5. The mean catch per pot of crab among the net fishing basket, pipe type fishing baskets, plate type tangle net were highest in the pipe type fishing baskets than the net fishing basket and lowest plate type tangle net. Therefore it showed to difference against the tank experiment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5A
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• pp.307-315
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• 2012

Recently, ultra high performance fiber reinforced concrete (UHPFRC) having over 180 MPa compressive strength and 10 MPa tensile strength has been developed in Korea. However, UHPFRC represents different material properties with normal concrete (NC) and conventional high performance concrete (HPC) such as a high early age autogenous shrinkage and a rapid dry on the surface, because it has a low water-binder ratio and high fineness admixtures without coarse aggregate. In this study, therefore, to propose suitable experimental methods and regulations, and to evaluate mechanical properties at a very early age for UHPFRC, setting, shrinkage and tensile tests were performed. From the setting test results, paraffin oil was an appropriate material to prevent drying effect on the surface, because if paraffin oil is applied on the surface, it can efficiently prevent the drying effect and does not disturb or catalyze the hydration of cement. From the ring-test results, it was defined that the shrinkage stress is generated at the time when the graph tendency of temperature and strain of inner steel ring is changed. By comparing with setting test result, the shrinkage stress was firstly occurred as the penetration resistance of 1.5 MPa was obtained, and it was about 0.6 and 2.1 hour faster than those of initial and final sets. So, the starting time of autogenous shrinkage measurement (time-zero) of UHPFRC was determined when the penetration resistance of 1.5 MPa was obtained. Finally, the tensile strength and elastic modulus of UHPFRC were measured from near initial setting time by using a very early age tensile test apparatus, and the prediction models for tensile strength and elastic modulus were proposed.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.55-66
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• 2005

Cnidii Rhizoma (CR) was subjected to extraction with 70% methanol and tested to determine whether it has anxiolytic activity in mouse by employing staircase and rotarod tests. In addition, to understand the mechanism of anxiolytic action, CR, picrotoxin, yohimbine, isoniazid and strychnine were utilized to deliniate the potential involvement of GABA and glycine receptors in the action of Cnidii Rhizoma. To gain insights into the safety of Cnidii Rhizoma extract, behavioral and MTT tests were carried out. The results were obtained as follows: 1. CR extract had little effect on climbing numbers in the stair case test. 2. CR extract had considerable anti-anxiety effects as evidenced by the reduction of rearing numbers in the stair case test. 3. CR extract had little effect on muscle relaxation. 4. Anxiolytic actions of CR extract appeared to be mediated by glycine receptor activation. 5. Cytotoxicity in the neuronal cell was not observed and no strange behaviors were found. In short, these results indicate that CR extract has the ability to exert anxiolytic activity, possibly by activating glycine receptor with little side effects in mouse.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.37-45
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• 2024

Purpose: This study aimed to examine the clinical features and determinants of macrolide-unresponsive Mycoplasma pneumoniae pneumonia (MUMP) and to assess the differences in the time to fever resolution between doxycycline (DXC), tosufloxacin (TFX) and corticosteroid (CST) as second-line treatment. Methods: We retrospectively analyzed the medical records of patients under the age of 18 who were admitted to Nowon Eulji University Hospital between July 2018 and February 2020, diagnosed with mycoplasma pneumonia. Macrolide resistance was confirmed by detecting point mutations in the 23S rRNA gene. MUMP was clinically defined by persistent fever (≥38.0℃) lasting for 72 hours or more after the initiation of macrolide treatment. In cases of MUMP, patients were treated with an addition of CST, or the initial macrolide was replaced either DXC or TFX. Results: Out of 157 cases of mycoplasma pneumonia, 83 cases (52.9%) did not respond to macrolides. Patients with MUMP exhibited significantly higher C-reactive protein (CRP) levels (3.2±3.0 vs. 2.4±2.2 mg/dL, P=0.047), more frequent lobar/segmental infiltrations or pleural effusions (56.6% vs. 27.0%, P<0.001; 6.0% vs. 0.0%, P=0.032), and a higher prevalence of 23S rRNA gene mutations (96.4% vs. 64.6%, P<0.001) when compared to those with macrolide-susceptible M. pneumoniae pneumonia. In terms of second-line treatment, 15 patients (18.1%) responded to CST, 30 (36.1%) to DXC, and 38 (45.8%) to TFX. The time to defervescence (TTD) after initiation second-line treatment was significantly shorter in the CST group compared to the DXC (10.3±12.7 vs. 19.4±17.2 hours, P=0.003) and TFX groups (10.3±12.7 vs. 25.0±20.1 hours, P=0.043), with no significant difference observed between the DXC and TFX groups (19.4±17.2 vs. 25.0±20.1 hours, P=0.262). Conclusions: High CRP levels, the presence of positive 23S rRNA gene mutation, lobar or segmental lung infiltration, and pleural effusion observed in chest X-ray findings were significant factors associated with macrolide unresponsiveness. In this study, CST demonstrated a shorter TTD compared to DXC or TFX. Further, larger-scale prospective studies are needed to determine the optimal second-line treatment for MUMP.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.505-515
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• 1998

Purpose : This study is intended to understand the sensitometric characteristics and the emulsion properties of the commercially available CEA TVS film in comparison with the Kodak X-Omat V film. Materials and Methods : For this purpose, we have formulated an analytic expression of the characteristic curves for x-ray film exposed to mixed radiation of electrons, photons, and visible light. This mathematical expression was developed based on reaction-rate and target-hit theories. Unlike previous expressions. it relates optical density to emulsion properties such as grain size and silver bromide content We have also developed a quantity which characterizes the film response to visible light relative to that to photons and electrons. This quantity could be expressed as a function of grain area. Thus, we have developed mathematical expressions and quantities with which the emulsion properties of the films can be revealed based on the sensitometric characteristics. Demonstrating the use of this analytical study, we exposed CEA and Kodak verification films to the mixed radiation of electrons, photons, and visible light, and interpreted the experimental results accordingly. Results : We have demonstrated that: (1) the saturation density increases as the silver bromide content increases, (2) the time required to reach the threshold dose (to which the film begins to respond) when films are exposed to visible light decreases as the grain size increases, and (3) the CEA film contains more silver bromide. whereas the Kodak film contains larger grains. These findings were supported by the data provided by the manufacturers afterward. Conclusion : This study presented an analytical and experimental basis for understanding the response of X-ray film with respect to the emulsion properties.

• Biomedical Science Letters
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• v.2 no.2
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• pp.223-229
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• 1996

HLA-B27 gene, one of the HLA-class I molecule, is strongly associated with ankylosing spondylitis. It has been most frequently used as a disease-correlated HLA gene by clinicians. In most laboratories, conventional HLA-B27 typing is still performed by cell cytotoxicity tests or fluorescence serology with specific antibodies. In this study, DNA typing method for HLA-B27 was developed by using group specific Polymerase Chain Reaction (PCR). Four HLA-B27 cell lines (HOM-2, JESTHOM, WT24 and BTB) and fifty six B27 Korean individuals defined by serology were used. The results of control cell and B-27 positive individual samples were correlated well with the data which was performed by serological method. All of B27 positive PCR products gave positive signals on Southern blot hybridization with B27 specific probe. This study shows that the HLA-B27 DNA typing is a relatively simple, fast and practical tool for the determination of the HLA-B27 gene in routine clinical laboratory work.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.2
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• pp.108-113
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• 2014

This study was conducted to evaluate the performance of Italian ryegrass cultivars for salt tolerance under in vitro condition. Italian ryegrass cultivars such as Greenfarm, Florida80, Kowinearly, and Hwasan101 were tested for their tolerance to various sodium chloride levels (0, 50, 150, 250, and 350 mM). The seed germination, growth, and activities of antioxidant enzymes were investigated under salt treatment. Physiological traits such as seed germination percentage, germination period, shoot and root length, and dry weight were suppressed under entire salt stress conditions. The results indicated that the highest germination percentage and shoot and root length were recorded at normal conditions. Increased sodium chloride levels caused a significant reduction in the seed germination and growth rate. Among the four tested cultivars, Italian ryegrass 'Hwasan101' could be considered as salt tolerant owing to its higher germination percentage, better seedling growth and antioxidant activities under salinity stress, whereas Greenfarm cultivar was more sensitive. The selection of Italian ryegrass cultivars for greater tolerance to saline environment would allow greater productivity from large saline lands.

• Journal of Life Science
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• v.21 no.7
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• pp.947-952
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• 2011

A number of epidemiological studies have identified human papillomavirus (HPV) types 1, 2, 3, 4, 7, 10, 27, 57, and 65 in cutaneous common warts. However, identification of the HPV subtype by conventional polymerase chain reaction (PCR) is time consuming with its multi-step laboratory process. In this study, we aim to develop a specific one-step multiplex polymerase chain reaction method which capably identifies six different HPV genotypes related to common warts. By HPV DNA sequence analysis, 6 pairs of specific primers were designed from the intergenic regions of genes L1 to E6, and from genes E2 to L2. DNA sequence analysis with the L1 gene sequence of the sample was performed to measure the specificity of multiplex PCR. HPV-1, -2, -3, -4, -27, and -57 were identified without cross amplification in 109 out of 129 samples. The sensitivity and specificity of our set of primers in detecting HPV were 85% and 99.5%, respectively. For the 20 samples where HPV type was not identifiable by our batch of primer sets, multiplex PCR with an additional set of HPV primers was done, where 7 were found positive for HPV-7 or -65. Our results demonstrate that the newly designed multiplex PCR can rapidly detect the specific HPV subtype involved in common warts with high accuracy.