• Clinical and Experimental Pediatrics
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• v.57 no.6
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• pp.271-277
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• 2014

Purpose: A nationwide outbreak of Mycoplasma pneumoniae pneumonia (MP) refractory to macrolide antibiotics occurred in Korea during 2011. Steroid therapy has been reported to be both efficacious and well tolerated in pediatric patients with refractory MP. We compared clinical features and laboratory characteristics between children with refractory MP requiring steroid treatment and those with macrolide-responsive MP and evaluated the risk factors associated with refractory MP. Methods: We investigated 203 children who were admitted to our institution with MP from June to November 2011. Refractory MP was defined by persistent fever over $38.3^{\circ}C$ with progressive pulmonary consolidation or pleural effusion despite administration of appropriate macrolide antibiotics for 5 days or longer after admission. Steroid therapy was initiated on the fifth day after admission for refractory cases. Results: There were 26 patients with refractory MP requiring steroid therapy. The mean duration of steroid therapy was 5.4 days and most of the patients were afebrile within 24 hours after initiation of steroid therapy. The prevalence of refractory MP was higher in patients with pleural effusion, lobar pneumonia affecting more than 2 lobes, higher levels of serum lactate dehydrogenase, increased oxygen requirements, and longer duration of hospitalization. Atopic sensitization and history of asthma were also associated with refractory MP after adjusting for age and gender. Conclusion: Children with refractory MP had more severe pneumonia. Atopic sensitization and history of asthma may be risk factors for refractory MP requiring steroid therapy in Korean children.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.310-315
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• 2000

We analyzed thermal stress of the STS VOD ladle by the variation of material property of refractory, and determined the location of back filler using FE analysis. Thermal distribution of refractory of ladle between hot face and back face were decreased by the increasing the thermal conductivity, and thermal stress of refractory were decreased about 2 to 4 times with the decreasing the young's modulus coefficients. Back filler, which is constructed to absorb the thermal expansion of dolomite refractory, has relatively low thermal conductivity. Inner side of refractory of ladle maintained high temperature, but temperature of outer side of ladle decreased low. Consequently, inner expansion and outer contraction were appeared. and thermal stress were increased, so thermal stress by the construction of back filler were increased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.38-39
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• 2016

In this research, the possibility of wasted refractory powder pulverized from refractory block as an expansive admixture and additional alkaline stimulant for class two and three blast furnace slag cements (BSC) was assessed with its high content of free CaO or free MgO. As the replacement ratios of wasted refractory powder and blast furnace slag were increased, flow and air content were decreased, while unit volume weight was increased under same conditions. Compressive strength of mortar was increased with increased replacement ratio of wasted refractory powder, especially, in the case of class three BSC, the highest compressive strength was obtained when wasted refractory powder was replaced 10 %.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.139-140
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• 2016

In this research, the possibility of wasted refractory aggregate pulverized from refractory block as an expansive admixture and additional alkaline stimulant for class two and three blast furnace slag cements (BSC) was assessed with its high content of free CaO or free MgO. As the replacement ratios of wasted refractory powder and blast furnace slag were increased, flow and air content were decreased, while unit volume weight was increased under same conditions. Compressive strength of mortar was increased with increased replacement ratio of wasted refractory powder, especially, in the case of class three BSC, the highest compressive strength was obtained when wasted refractory aggregate was replaced 2%.

• Journal of Powder Materials
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• v.30 no.6
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• pp.478-483
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• 2023

High-entropy alloys (HEAs) are characterized by having five or more main elements and forming simple solids without forming intermetallic compounds, owing to the high entropy effect. HEAs with these characteristics are being researched as structural materials for extreme environments. Conventional refractory alloys have excellent high-temperature strength and stability; however, problems occur when they are used extensively in a high-temperature environment, leading to reduced fatigue properties due to oxidation or a limited service life. In contrast, refractory entropy alloys, which provide refractory properties to entropy alloys, can address these issues and improve the high-temperature stability of the alloy through phase control when designed based on existing refractory alloy elements. Refractory high-entropy alloys require sufficient milling time while in the process of mechanical alloying because of the brittleness of the added elements. Consequently, the high-energy milling process must be optimized because of the possibility of contamination of the alloyed powder during prolonged milling. In this study, we investigated the high-temperature oxidation behavior of refractory high-entropy alloys while optimizing the milling time.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.441-444
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• 2007

The inside wall of a coal gasifier is lined with refractory, and the corrosion of the refractory by coal sag is an important parameter affecting the refractory lifetime and the replacement period. This paper examines the changes in microstructure of a chromia refractory due to chemical reactions with penetrating slag as a function of slag composition. The effects of CaO and $Fe_2O_3$ concentrations were studied using Datong and KIDECO slag. Static corrosion experiments were carried out, the percent slag penetration and changes in the microstructure were determined by SEM/EDX analyses. FactSage equilibrium calculations were carried out to determine the equilibrium products and the predictions were compared with experimental observations.

• Journal of the Korean Ceramic Society
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• v.33 no.7
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• pp.832-838
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• 1996

Thermite reaction products of MgO and Al were added to MgO-C refractory to improve the properties of corrosion against the attack of slag, oxidation and mechanical spalling. Corrosion rate of MgO-C-MgAl2O4 spinel refractory at the ratio of 3.3(CaO/SiO2) slag was smaller than that of MgO-C and MgO-C-Al refractory. The excellent corrosion resistance of the MgO-C-MgAl2O4 spinel refractory against the slag attack was appeared by Al and MgAl2O4 spinel with high melting point and corrosion resistance and the high thermal conductivity and low thermal expansion of AIN. Hot M.O.R at 140$0^{\circ}C$ and the resistance of oxidation weight loss at 90$0^{\circ}C$ were 210kg/cm2 and -12% respectively.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.21
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• pp.9291-9293
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• 2014

Background: Patients with refractory or relapsed multiple myeloma are considered to have a very poor prognosis, and new regimens are needed to improve the outcome. Gemcitabine, a nucleoside antimetabolite, is an analog of deoxycytidine which mainly inhibits DNA synthesis through interfering with DNA chain elongation and depleting deoxynucleotide stores, resulting in gemcitabine-induced cell death. Here we performed a systemic analysis to evaluate gemcitabine based chemotherapy as salvage treatment for patients with refractory and relapsed multiple myeloma. Methods: Clinical studies evaluating the impact of gemcitabine based regimens on response and safety for patients with refractory and relapsed multiple myeloma were identified by using a predefined search strategy. Pooled response rate (RR) of treatment were calculated. Results: In gemcitabine based regimens, 3 clinical studies which including 57 patients with refractory and relapsed multiple myeloma were considered eligible for inclusion. Systemic analysis suggested that, in all patients, pooled RR was 15.7% (9/57) in gemcitabine based regimens. Major adverse effects were hematologic toxicity, including grade 3 or 4 anemia, leucopenia and thrombocytopenia i. No treatment related death occurred with gemcitabine based treatment. Conclusion: This systemic analysis suggests that gemcitabine based regimens are associated with mild activity with good tolerability in treating patients with refractory or relapsed multiple myeloma.

• The Korean Journal of Pain
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• v.25 no.2
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• pp.121-125
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• 2012

Refractory angina pectoris is defined as angina refractory to optimal medical treatment and standard coronary revascularization procedures. Despite recent therapeutic advances, patients with refractory angina pectoris are not adequately treated. Spinal cord stimulation is a minimally invasive and reversible technique which utilizes electrical neuromodulation by means of an electrode implanted in the epidural space. It has been reported to be an effective and safe treatment for refractory angina pectoris. We report a case of spinal cord stimulation which has effectively relieved chest pain due to coronary artery disease in a 40-year-old man. This is the first report of spinal cord stimulation for treatment of refractory angina pectoris in South Korea.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.397-404
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• 2011

This research investigates the runoff characteristics of refractory organic matters from Kyongan river watershed. Samples were taken 27 times during dry season, 4 times during rain events and analyzed into flow rate, Dissolved Organic Carbon (DOC), Particulate Organic Carbon (POC), Refractory Dissolved Organic Carbon (R-DOC), Refractory Particulate Organic Carbon (R-POC). R-DOC during dry season was the lowest in winter and showed a rising tendency in spring and R-POC changes less than R-DOC. The mass loading of Refractory Total Organic Carbon (R-TOC) in summer takes approximately 80% of 1 year mass loading. During rainy season, EMC of R-DOC was similar to R-DOC in dry season. But maximum EMC of R-POC was 12 times higher than that of R-POC in dry season. Results of the survey show that enhanced management of R-DOC in dry season and R-POC in rainy season is needed.