• Clinical and Experimental Pediatrics
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• v.48 no.4
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• pp.416-424
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• 2005

Purpose : To find the risk factors associated with coronory artery lesions, non-responsiveness to intravenous immunoglobulin(IVIG) treatment, and recurrences in Kawasaki disease patients. Methods : We retrospectively analyzed 1,000 Kawasaki disease patients who were admitted to Yonsei University Medical Center from September 1990 to December 2003. We compared between responder and non-responder groups to IVIG treatment as well as between relapsed and non-relapsed groups, and as to the relapsed group, we also compared variables between patients in their first and second attack states. Finally, factors associated with longer-fever duration from disease onset were evaluated. Results : Longer fever durations before and after IVIG treatment, male sex, lower Hgb and Hct level, higher WBC count and segmented WBC proportion, and higher CRP and Harada's score were related with coronary artery lesions. Non-responsiveness was related to higher WBC count, segmented WBC proportion, CRP, SGPT, Harada's score, and pyuria. Moderate-to-severe coronary artery dilatations and recurrences were more commonly seen among the non-responder group. No significant predictive factors for recurrence were found. In the relapsed group, lower WBC count, CRP, and shorter fever duration from disease onset were observed in their second attack state. Fever duration from disease onset showed positive correlation with WBC count, CRP, and Harada's score and negative correlation with Hgb levels. Conclusion : Higher WBC count, CRP, and higher Harada's score were related to both higher incidences of coronary artery lesions and non-responsiveness to IVIG treatment, and these factors were also related with longer fever duration. Non-responders to IVIG treatment showed higher recurrence rate and more moderate-to-severe coronary artery dilatations than responders.

• Journal of Energy Engineering
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• v.22 no.4
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• pp.355-361
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• 2013

In this work, torrefaction of the sewage sludge was investigated the characteristics of torrefied products and the value of as energy resource to improve energy density and to maintain consistent quality of SRF. Torrefaction was performed two important torrefaction operational parameter, temperature($150-230^{\circ}C$) and reaction time(10-60min). As raising the torrefaction temperature at long reaction times, the moisture content of torrefied products was decreased, while the heating value was increased. Moreover, increasing of the torrefaction temperature led to a increase of the content of the carbon up to 60% compare to the initial the sample, and a decrease of the content hydrogen and oxygen. Especially, Average heating value was 4,818 kcal/kg regardless of the reaction time when torrefaction was performed over $210^{\circ}C$. In addition, the fuel ration and coal band were improved after torrefaction because the O/C and the H/C ratio were decreased.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.113-119
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• 2019

Concrete structures built on reclaimed land are combined with chemical erosion such as chlorine and sulfate ions from seawater. Chloride attack deteriorates the performance of the structure by corroding reinforcing bars. In addition, the waste water treatment structure has a problem that the concrete is deteriorated by the sulfate generated inside. Therefore, in this study, the characteristics and chemical resistance of low heat cement concrete used in wastewater treatment structures constructed on reclaimed land were evaluated. As a result of the experiment, the target slump and air content were satisfied under all the mixing conditions. The slump of low heat cement (LHC) concrete was higher than that of ordinary portland cement (OPC) concrete, while the air content of LHC concrete was smaller than that of OPC concrete with the same mix proportion. As a result of compressive strength test, OPC concrete showed higher strength at younger age compared to 28 days. In contrast, LHC concrete exhibited higher strength than OPC concrete at the age of 56 days. As a result of chlorine ion penetration tests, LHC-B concrete showed chlorine ion penetration resistance performance of the "very low" level at the age of 56 days. As a result of chemical resistance evaluation, when the LHC concrete is applied without epoxy treatment, chemical resistance is improved by about 18% compared to OPC concrete. In testing chemical resistance, the epoxy coated concrete exhibited less than 5% strength reduction when compared to sound concrete.

• Pediatric Infection and Vaccine
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• v.8 no.2
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• pp.253-259
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• 2001

Kikuchi's disease(histiocytic necrotizing lymphadenitis) is characterized by lymphadenopathy in young patients below 30 years old, and persistent fever, lymphopenia and splenomegaly are concomitantly developed in many cases. So, it has been confused with lymphoma, SLE, and tuberculosis, and has easily led to inappropriate diagnostic procedures and administration of drugs. Many reports have indicated that Kikuchi's disease should be added to the list of causes of FUO in the setting of lymphadenopathy, and recommended early lymph node biopsy to distinguish from lymphoma, SLE, and tuberculosis to avoid unnecessary treatments. We experienced a case of subacute necrotizing lymphadenitis in a 14-year-old boy who presented with persistent high fever, productive coughing and cervical lymphadenopathy for about 1 month. Initially, diagnostic workup was done to look for the causes of FUO in vain. Finally, we confirmed diagnosis by histopathological findings of lymph node biopsy and detected latent gene of EBV in the biopsied specimen using in situ hybridization.

• Resources Recycling
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• v.20 no.3
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• pp.62-67
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• 2011

This study has been investigated for characteristic of removal on the effect of changes in soil moisture, microwave power, and temperature through the decomposition of oil-contaminated soil under high temperature conditions with high temperature heating elements and microwave. A lubricating oil having long carbocyclic(C18-C50) commonly known as a non-resolvable material was treated and the efficient for removal of TPH(Total Petroleum Hydrocarbon) obtained 85.2% at 6 kW and $700^{\circ}C$ and thus the contaminant was found to be removed to 1788 mg/kg for 40 minutes. In case of contaminated soil by light oil and gasoline, the amount of removal was achieved with 567 mg/kg at 6 kW, 500 for 20 minutes that corresponds to reach 98.4% of treatment efficient. In addition, non-resolvable materials contaminated by oil reached TPH concentration on 2,000 mg/kg of worrisome level of soil contamination in the 3-zone at 6kW, $700^{\circ}C$, and 30 minutes, and processing cost at this time was about 8,173 won per ton.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.7
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• pp.749-755
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• 2011

The performance and emission characteristics of a CNG (compressed natural gas) engine were experimentally investigated under different natural gas compositions. The engine specifications were as follows: 6606 cc, turbo, lean-burn-type; its ignition timing was fixed for the fuel gas with a HHV (higher heating value) of 10454 kcal/$Nm^3$. The experimental results showed that when the HHV of the fuel gas was changed from 10454 kcal/$Nm^3$ to 9811 kcal/$Nm^3$ and 9523 kcal/$Nm^3$, the average power reductions were 3.2 % and 3.4 % (1.5 % and 2.1 %, respectively, with A/F control switched off), respectively, and the average thermal-efficiency reductions were 1.1 % and 1.5 % (1.5 % and 2.1%, respectively, with A/F control switched off), respectively. The emissions of $CO_2$, CO, and $NO_x$ decreased as the HHV of the fuel gas was lowered. On the other hand, the emissions of THC (total hydrocarbon) were not consistent, and the extent of change in their emissions was small.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1015-1020
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• 2012

Lignite of low rank coal and petroleum coke of high sulfur content can be high potential energy sources for coal gasification process because of their plentiful supply. The steam gasification of lignite, anthracite, and pet coke has been carried out in both an atmospheric thermobalance reactor and a lab-scale fludized bed reactor (0.02 m i.d. ${\times}$ 0.6 m height). The effects of gasification temperature ($600{\sim}900^{\circ}C$) and partial pressure of steam (0.15~0.95 atm) on the gasification rate and on the heating value of product gas have been investigated. The modified volumetric reaction model was applied to the experimental data to describe the behavior of carbon conversion, and to evaluate kinetic parameters of char gasification. The results shows that higher temperature bring more hydrogen in the product syngas, and thus increased gas heating value. The feed rate of steam is needed to be optimized because an excess steam input would lower the gasification temperature which results in a degradation of fuel quality. The rank of calorific value of the product gas was anthracite > lignite > pet coke. Their obtained calorific value at $900^{\circ}C$ with 95% steam feed were 10.0 > 6.9 > 5.7 $MJ/m^3$. This study indicates that lignite and pet coke has a potential in fuel gas production.

• Fire Science and Engineering
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• v.34 no.1
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• pp.11-17
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• 2020

As performance-based design (PBD) has a direct impact on evacuation safety assessments, designing fire scenarios based on real fire tests is essential. To improve the reliability of the PBD for fire safety in multiplexes, information on fire behavior, such as heat release rate (HRR) and fire spread rate, are provided in this study by conducting a standard fabric flammability test. To this end, several chairs were arranged in a pattern that resembled a theater-style seating. The peak HRR and heating value per unit mass for each chair ranged from 415 kW to 988 kW and 15.2 MJ/kg to 23.8 MJ/kg, respectively. The heating values per unit mass of the new and old chairs were 23.6 MJ/kg and 16.7 MJ/kg, respectively. As the quantity of plastic and cushioning materials in the new chairs was more than that of the old ones, the new chairs were more vulnerable to fire hazards. Furthermore, when the chairs were arranged in a line, the fire spread rate was observed to be 0.39-0.42 m/min, regardless of the ignition location. Finally, a fire growth curve showing the peak HRR and fire spread rate was also demonstrated.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.739-744
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• 2013

In this study, torrefaction was performed to improve fuel properties of Larch. The optimal condition for torrefaction was investigated by response surface methodology. The torrefaction temperature and time ranged $220{\sim}280^{\circ}C$ and 20~80 min, respectively. As the torrefaction temperature and time increased, the carbon content of torrefied biomass increased from 49.36 to 56.65%, while its hydrogen and oxygen contents decreased from 5.56 to 5.48% and from 37.62 to 31.67%, respectively. The weight loss and calorific value increased with SF, while energy yield decreased. At the severe torrefaction condition (SF 7), the weight loss and calorific value were 26.58% and 22.30 MJ/kg, respectively. The energy contained in torrefied biomass increased to 20.41%, when compared with the untreated biomass. As the torrefaction severity increased, the energy yield decreased due to the relatively high weight loss of biomass. Therefore, the highest energy yield was obtained at high calorific value and low weight loss of biomass (SF 5.72).

• Journal of Energy Engineering
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• v.26 no.3
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• pp.78-89
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• 2017

Spontaneous combustion propensity of various coals of carbonization grade as a pulverized fuel of coal fired power plant has been tested from an initial temperature of $25^{\circ}C$ to $600^{\circ}C$ by heated in an oven with air to analyze an self oxidation starting temperature. This tests produce a CPT(Cross Point Temperature), IT(Ignition temperature) and CPS(Cross Point Slope) by calculated as the slope of time taken a rapid exothermic oxidation reaction at CPT base. CPS show a carbonization rank dependence, whereby wood pellet has the highest propensity to spontaneous combustion of $20.995^{\circ}C/min$. A subbituminous KIDECO coal shows an CPS values of $15.370^{\circ}C/min$ whereas it of pet coke of the highest carbonization rank has $20.950^{\circ}C/min$. The nature of this trend is most likely a concentration of volatile matter and oxygen functional groups of coal surface that governs the available component for oxidation as well as surface area of fuel char, and constant pressure molar heat.