• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.513-516
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• 2017

When stored for long periods in a powder-based device (PMD), the explosive power in the device is aged and the explosive power is changed. Thus, The gunpowder used in the PMD must be chemically and physically stable for both internal and external factors. Since $BKNO_3$ and THPP are used as representative gunpowder, thermodynamic and kinetic analyzes were performed based on these gunpowders. Differential scanning calorimeter (DSC) was used to analyze the calorific value and reaction rate. As a result, there was no significant change in caloric value and reaction rate in THPP. In addition, XPS and TEM-EDS analyzes were performed to confirm the formation of oxide films directly related to aging, and no oxide films were observed as a result of thermal analysis. In addition, XPS and TEM-EDS analyzes were performed to confirm the formation of oxide films directly related to aging. As a results, no oxide films were observed. It can be concluded that THPP is the most famous gunpowder in terms of long-term stability.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.120-127
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• 2022

Nitrogen oxide(NOx) is a major cause of air pollution, exists in the form of nitrogen monoxide and nitrogen dioxide, and is harmful to the human body. Recently, a number of studies to reduce NOx in the atmosphere have been conducted, and these efforts have been the same in the field of construction materials. It is known that NOx can be efficiently removed by using a photocatalytic reaction. In this study, the NOx removal performance of the foam composite using activated carbon(AC) and titanium dioxide(TiO₂) was investigated. AC was used to enhance the photocatalytic reaction of TiO₂ by increasing the internal specific surface area of the foam composite. In this study, foam composites were prepared using the substitution rate of AC as the main variable. The NOx removal performance of specimen was evaluated according to the test method presented in ISO-22197-1. The specific surface area of the foam composite showed a tendency to increase according to the AC content, but decreased at 15% or more. Also, when the AC substitution rate was 15%, the NOx removal efficiency was the highest.

• Corrosion Science and Technology
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• v.5 no.4
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• pp.129-136
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• 2006

High temperature corrosion behavior of AISI-type 316L stainless steel for the MCFC(molten carbonate fuel cell) bipolar application was studied by immersion test and penetration attack method in anode environment ($650^{\circ}C$, $Li_2CO_3/K_2CO_3=62/38$ mol%, $H_2/CO_2=80/20$ vol%) without or with different $CaCO_3$ content. Not only immersion test method but also morphological observation of samples in the carbonate melts are adopted as experimental methods. With aid of the morphological observation of cross section of samples immersed in a carbonate melt was possible to obtain penetration attack. The concentration effect of $CaCO_3$ inhibitor was investigated in order to verify the optimum concentration for practical application in MCFC stack operation. The corrosion rate in the presence of $CaCO_3$ was proven to be decreased as a function of $CaCO_3$ concentration. The corrosion rate in the presence of $CaCO_3$ was measured with a value of 6.9 mpy which is 2.4 times lower than that of inhibitor-free electrolyte. The cross section microscopy revealed that the internal penetration by oxidation in molten carbonate is very severe. In this case, the attack was occurred not only dissolution loss in the electrolyte by corrosion reaction but also weight gain through oxide layer by internal penetration.

• Journal of Energy Engineering
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• v.14 no.4 s.44
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• pp.268-276
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• 2005

Vacuum Residue (VR) combustion tests were carried out with a 20 kg/hr (fuel feed rate) small scale reactor. The nozzle used was a steam atomized, internal mixing type. Compared to heavy oil, vacuum residue used in this work is extremely high viscous and contains high percentages of sulfur, carbon residue and heavy metals. To ignite atomized VR particles, it was necessary to preheat the reactor, and it has been done with LP gas. The axial and radial gas temperature, major species concentrations and solid sample were analyzed when varying the fuel feed rate. The main reaction zone of atomized VR-air flame in a reactor was anticipated within about 1 m from the burner tip by considering the profiles oi gas temperature, species concentration and particle size measured along with the reactor. At downstream, the thermally, fully developed temperature distribution was obtained. SEM photographs revealed that VR carbon particles collected from the reactor are porous and have many blow-holes on the particle surface.

• Tuberculosis and Respiratory Diseases
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• v.69 no.3
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• pp.163-170
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• 2010

Background: Pulmonary tuberculosis remains a health concern in Korea despite major progress in the development of new strategies for diagnosing and treating tuberculosis. In particular, the diagnosis of newly developed pulmonary tuberculosis is on the rise in elderly persons. The aim of this study was to investigate the clinical, radiographic characteristics, and treatment outcomes of pulmonary tuberculosis in the elderly. Methods: The medical records of 113 young (<65 years old) and 112 elderly (${\geq}65$ years old) pulmonary tuberculosis patients diagnosed at Chungnam National University hospital between January 2007 and December 2008 were reviewed. Results: There was no difference in the prevalence of typical symptoms between the younger and the elderly group. Dypsnea was the only symptom that occurred more frequently in the elderly group (16.8% vs 5.5%, p=0.008). On radiological study, pneumonic infiltration type was more common in the elderly group (28.6% vs 16.8%, p=0.035). Sputum Acid fast bacilli smear positivity rate was similar between the 2 groups. Elderly patients with anti-tuberculosis medication had more frequent adverse drug reactions; however, there was no significant difference between the 2 groups in the number of patients required to stop medication due to an adverse drug reaction. There were more patients lost to follow-up in the elderly group (22/112, 19.6% vs 11/113, 9.7%, p=0.036). Conclusion: The majority of elderly patients did not complete the treatment, resulting in a poorer outcome. Therefore, we need to make an effort to support the continued screening of elderly patients by making this economically feasible.

• Applied Chemistry for Engineering
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• v.5 no.3
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• pp.385-394
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• 1994

Numerical solutions were obtained to the model equations for various of the parameters characterizing the pore structure, effective internal diffusion, and the chemical reaction constant. The conversion was decreased with the cause of pore closure at the surface of reacting particles, reduction of porosity, surface area of reaction and effective diffusion coefficient in the solid with the progress of reaction. Total conversion was strongly dependent on the local conversion at surface. According to the decreasing of impregnated concentration of the copper oxide and the increase of the flue gases concentration, total conversion was increased. The conversion was affected by gas flow rate and pore size distribution in the reacting solid.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.113-132
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• 2021

This study is a new evaluation using the Arrhenius equation, which is known as the chemical reaction rate estimation equation, to evaluate the intrinsic and extrinsic value elements of patents as a model. The performance of the evaluation model was superior to the SVM, Logistic reg. and ANN models that were used as patent evaluation models in prior studies. In addition, there was a strong correlation between the predicted lifespan of the patent and the actual lifespan of the patent. These evaluation models may be used for evaluation purposes only, or if an evaluation is required, including a commercialization entity or technical characteristics.

• Tuberculosis and Respiratory Diseases
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• v.70 no.4
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• pp.315-322
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• 2011

Background: A variety of diagnostic modalities for lung cancer have been developed. To achieve efficient and early detection of lung cancer, we tried to measure the expression rates of the melanoma associated gene (MAGE) and synovial sarcoma on X chromosome (SSX) genes. Methods: We designed primers for the SSX gene. In addition to the pre-developed MAGE A primer, using an SSX gene primer was attempted to increase the detection rate. We obtained cancer tissues and cancer-free lung tissues from resected lung, sputum from lung cancer patients who had not undergone surgery, and sputum from healthy people and patients with benign intrathoracic diseases. Results: The sensitivity of the MAGE or SSX gene RT-PCR to identifying cancer tissue of the 69 lung cancer patients was 95.2% for squamous cell carcinoma (scc), 87.0% for adenocarcinoma, and 100% for small cell carcinoma. The mean sensitivity value was 94.2% (p=0.001). For adenocarcinoma, the additional use of the SSX gene resulted in a higher expression rate than MAGE alone (87% vs. 69.6%). The expression rate for the cancer-free lung tissue was 14.3% in scc, 17.4% in adenocarcinoma, and 25.0% in small cell carcinoma. In the induced sputum of 49 lung cancer patients who had not undergone surgery, the expression rate for one of the two genes was 65.5%. The expression rate for the sputum of healthy people and benign intrathoracic diseases by MAGE or SSX gene reverse transcription polymerase chain reaction (RT-PCR) was 3.8% and 17.7%. Conclusion: Detecting lung cancer using the expression of MAGE and SSX genes in lung cancer tissue has high sensitivity.

• Tuberculosis and Respiratory Diseases
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• v.43 no.1
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• pp.14-21
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• 1996

Objectives: Although outbreak of MDR Tb has been a recent problem in western countries, it has been a longstanding problem in Korea. The poor outcome of MDR Tb is mainly due to poor compliance, high rate of side reaction of secondary drugs, and limitation in number of available drugs. Thus, to improve the outcome of MDR Tb, it is crucial to make individualized adequate prescription based on the knowledge of the patterns of resistance to each drugs in the community as well as the natural history. The purpose of present study is to evaluate the clinical features of Korean MDR Tb patients including patterns of drug resistance and success rate of treatment which was prescribed according to the sensitivity tests. Methods: Retroscpective analysis of 71 Korean patients with MDR Tb was made. All strains isolated from patients showed resistence to at least two first line drugs. Patients profile, previous treatment history, patterns of drug resistance, outcome of treatment was analysed. Initial treatment regimen was selected according to the previous treatment history and was modified according to the sensitivity reports. The regimen was composed to include at least 4 sensitive drugs when possible. Results: The patients showed resistance to 4.1 drugs on average. 90% of them were resistant to INH and RFP. Among 71 patients, 35 patients(49%) had cavitary lesions in CXR. Treatment outcome was analysed in 55 patients. 35 patients(67%) were improved after treatment and 18 patients(33%) showed treatment failure. 5 patients showed primary resistance. Treatment outcome could be evaluated in 4 of them and all showed improvement after treatment. 14 patients(20%) had to change their regimens due to drug side effects. The most frequent side effect was elevation of liver enzymes(6 patients). Others included dizziness, hyperuricemia, tinnitus, skin rash, GI troubles. More than 50% of side effects developed within 3 months. In repeated drug sensitivity test, the concordance rate of resistance to INH was 100% and RFP 98%. EMB, PZA showed 80% concordance rate. But in the other drugs, the concordances were less than 50%. Operation was done in 5 patient - 1 patients as a adjunctive means of chemotherapy -. In that case, negative conversion of sputum AFB was done. Conclusion: 2/3 patients of multidrug-resistant tuberculosis were improved by appropriate prescription and regular medication suggesting that more aggressive management and monitoring is indicated in multidrug-resistant tuberculosis.

• The Journal of Korean Medicine
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• v.28 no.2 s.70
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• pp.54-65
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• 2007

Objectives : In the present study, the author investigated whether Naenghyo-hwan(NHH) significantly affect mucin secretion from airway epithelial cells. Methods : Confluent hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled with 3H-glucosamine for 24 hrs and chased for 30 min in the presence of NHH to assess the effect of the agent on 3H-mucin secretion. Total elutionprofiles of control spent media and treatment sample through Sepharose CL-4B column were analysed. Effect of NHH on contractility of isolated tracheal smooth muscle was investigated. Also, effect of the agent on MUC5AC gene expression in cultured NCI-H292cells was investigated. Possible cytotoxicities of the agent were assessed by measuring both lactate dehydrogenase (LDH) release from HTSE cells and examining the rate of survival and proliferation of NCI-H292 cells. Results : NHH significantly increased mucin secretion from cultured HTSE cells, with significant cytotoxicity. NHH chiefly affected the 'mucin' secretion. NHH inhibited ACh-induced contraction of isolated tracheal smooth muscle. NHH disturbed both the extraction of total RNA from NCI-H292 cells and polymerase chain reaction, nonspecifically. Therefore, in this experiment, theeffect of NHH on the expression levels of MUC 5AC gene in cultured NCI-H292 cells could not be elucidated. Conclusions : The author suggests that the effect of NHH with their components should be further investigated and it is valuable to find, from oriental medical prescriptions, novel agents which might regulate mucin secretion from airway epithelial cells.