• Pediatric Infection and Vaccine
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• v.15 no.2
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• pp.180-187
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• 2008

Purpose : We wanted to determine the characteristics of patients with Kawasaki disease (KD) who were unresponsive to intravenous immunoglobulin (IVIG). Methods : The patients with KD were divided into two groups: the IVIG responsive group (25 cases) and the IVIG unresponsive group (14 cases). We analyzed various parameters before and after the administration of IVIG, including the complete blood cell count with the differential count (%), the erythrocyte segmentation rate (ESR), the C-reactive protein (CRP) level and the protein and lipid profiles. Results : The IVIG unresponsive group had a prolonged duration of fever and a higher incidence of CAL compared to the IVIG responsive group (P<0.001, respectively). Before IVIG infusion, the neutrophil differential, the ESR and the CRP values were higher (P<0.001), and the total protein and albumin values were lower in the IVIG unresponsive group (P=0.01) compared to the IVIG responsive group. After IVIG infusion, there were no significant changes in the WBC count and CRP levels in the IVIG unresponsive group. The reduction of the HDL-cholesterol levels by IVIG was more significant in the unresponsive group (P=0.02). Conclusion : A more severe and prolonged inflammatory response occurred in the IVIG unresponsive group at an early stage, and this finding can be detected by such inflammatory parameters as the neutrophil count and the CRP and HDL-cholesterol levels after IVIG infusion.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.8
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• pp.39-48
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• 2016

In this paper, we propose thermal resistance compact model of FinFET structure that has hexagon shaped source/drain. The heating effect and thermal properties were increased by reduced size of the device, and thermal resistance is an important factor to analyze the effect and the properties. The heat source and each contact that is moved heat out were set up in transistor, and domain is divided by the heat source and the four parts of contacts : source, drain, gate, substrate. Each contact thermal resistance model is subdivided as a easily interpretable structure by analyzing the temperature and heat flow of the TCAD simulation results. The domains are modeled based on an integration or conformal mapping method through the structure parameters according to its structure. First modeled by analyzing the thermal resistance to a single fin, and applying the change in the parameter of the channel increases to improve the accuracy of the thermal resistance model of the multi-fin/ finger. The proposed thermal resistance model was compared to the thermal resistance by analyzing results of the 3D Technology CAD simulations, and the proposed total thermal resistance model has an error of 3 % less in single and multi-finl. The proposed thermal resistance model can predict the thermal resistance due to the increase of the fin / finger, and the circuit characteristics can be improved by calculating the self-heating effect and thermal characterization.

• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.389-397
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• 2010

Concrete has excellent mechanical properties, high durability, and economical advantages over other construction materials. Nevertheless, it is not an easy task to apply concrete to long span bridges. That's because concrete has a low strength to weight ratio. Ultra high performance concrete (UHPC) has a very high strength and hence it allows use of relatively small section for the same design load. Thus UHPC is a promising material to be utilized in the construction of long span bridges. However, there is a possibility of crack generation during the curing process due to the high binder ratio of UHPC and a consequent large amount of hydration heat. In this study, adiabatic temperature rise and mechanical properties were modeled for the stress analysis due to hydration heat. Adiabatic temperature rise curve of UHPC was modeled superposing 2-parameter model and S-shaped function, and the Arrhenius constant was determined using the concept of equivalent time. The results are verified by the mock-up test measuring the temperature development due to the hydration of UHPC. In addition, models for mechanical properties such as elastic modulus, tensile strength and compressive strength were developed based on the test results from conventional load test and ultrasonic pulse velocity measurement.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.4
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• pp.112-120
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• 2004

In this study, the physico chemical characteristic of MSW and sludge in west area of Kangwondo was investigated for database, managing the waste and waste treatment facility. The sampling sites were selected as 6 different MSW generation area and 2 sludge generation area. it is necessary to measure the characteristics of MSW to build the data-base. The year of 2000, 197.4ton/day of MSW which was generated in this area. This MSW was composed of 26.6% food wastes, 24.2% of papers, 22.8% of plastics & vinyls, 9.6% of textiles, 3.80% of wood, 2.8% of rubbers & leathers and others, respectively. Most of MSW are composed of food, paper and plastic waste and combustible waste is more than 89%. The generation of papers and vinyls are almost same for different seasons For 3-components of MSW, moisture is 40.2%, combustible component is 52.1% and ash is 7.7% and for 3-components of sludge, moisture is 83.3%, combustible component is 7.7% and ash is 9%. The chemical element has the high order of carbon(51.6%), oxygen(38.6%), hydrogen(7%) on the dry basis of wastes. And the high heating value of MSW is 4989.4 Kcal/kg sludge is 4428.04 Kcal/kg and low heating value of the MSW which is measured by calorimeter is 2032.88kcal/kg. From the leaching test of wastes, there is no heavy metals.

• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.230-236
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• 2009

Sewage sludge cake(SSC) is seriously concerned because ocean dumping, which is the cheapest treatment method now, will be banned in 2012. On the basis of this reason, recycling of SSC is emphasized to convert the treatment method. One of the method to recycling SSC could be carbonization process which also can be reduced greenhouse gas effectively. And carbonization residue of SSC produced by carbonization process can become a renewable energy source. However, carbonization process has not been evaluated by considering basic operating data such as heating value, yield and fuel ratio. In this study, the basic characteristics of SSC such as proximate analysis, elementary analysis and heating value are analyzed. In carbonization process, the effect of carbonization temperature and time on the residue of SSC are estimated. And the analysis is carried out to obtain basic properties of the residue of SSC. From the result of chemical composition of SSC residue, there is 27% of phosphate in SSC. Phosphate will take a role of reductant to convert from hazardous substance to non-hazardous material. As increased carbonization temperature and time, heating value and yield are decreased but fuel ratio(fixed carbon/volatile combustible) of the residue is increased. In the carbonization process, the optimum temperature and time in carbonization test for SSC can be decided by $250^{\circ}C$ and 15 min, respectively. However, the carbonization residue of SSC can not be deserved to use one of renewable energy sources because the heating value at the optimum condition is relatively low. Hence, it is desirable that SSC can be mixed with other organic waste to carbonize.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.737-742
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• 2015

An environmentally favorable solid oxidizer, guanidine dinitramide ($H_2C(NH_2)NH_2N(NO_2)_2$), with high purity and synthesis yield was prepared using guanidine carbonate ($NH_2C(=NH)NH_2{\cdot}1/2H_2CO_3$). Two different crystalline forms (${\alpha}$-form and ${\beta}$-form) were obtained depending on the solvent used and synthesis process. Despite of the same chemical composition, Raman-IR and TGA-DSC revealed that different structures existed between them. In particular, the thermal analysis showed the exothermic temperature of ${\alpha}$-form at $155.7^{\circ}C$ while $191.6^{\circ}C$ for ${\beta}$-form. The caloric value of ${\alpha}$-form was 536.4 J/g which was 2.5 times larger than that of ${\beta}$-form, 1310 J/g. In addition, ${\alpha}$-form was steeply decomposed with one-step variation, but ${\beta}$-form followed a two-step thermal decomposition pattern.

• Analytical Science and Technology
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• v.31 no.1
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• pp.31-38
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• 2018

The energy recovery rate estimation method proposed through the Waste Control Act does not take into account the energy used in practice. In addition, the method for measuring a lower heating value, which is the main factor of the energy recovery rate, was carried out through a small sampling amount, and thus the representative value of the waste was not reflected. With the revised estimation method (Notification No. 2015-215 of the Ministry of Environment), the energy recovery rate should be estimated based on the actual amount of energy used, and a heat balance method was proposed as a way to estimate the lower heating value. In this study, the lower heating value was estimated for seven industrial waste incineration facilities according to the revised estimation method. All data used in the estimations were achieved from measurement instruments applied to each of the incinerators and through direct measurements taken by the operators for the purposes of calculation. As a result, the lower heating value was estimated to be about 3,404.7 kcal/kg for the seven industrial waste incineration facilities.

• Journal of Adhesion and Interface
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• v.15 no.3
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• pp.100-108
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• 2014

In this work, a series of molar ratios composed with YD-128 and DDM were chosen based on the viscosity analysis. The mixtures of YD-128 and DDM with the different molar ratios were cured at $170^{\circ}C$ for 15 min followed by post cure at $190^{\circ}C$ for two hours. The thermal properties of the cured samples were investigated with DSC, TGA, DMA, and TMA. The conversion ratio of the mixtures of YD-128 and DDM (1 : 1.1) was calculated by dividing ${\Delta}H$ obtained from DSC experiments for each cured sample by ${\Delta}H$. The TGA data of the cured samples showed that the thermal stability and thermal degradation activation energy were proportional to the amount of DDM in the mixtures. However, the highest tan ${\delta}$, and the lowest thermal expansion data with DMA and TMA respectively were obtained from the stoichiometric mixture of YD-128 and DDM. Furthermore, the different ratio of mixtures were applied to test specimens to be cured at $170^{\circ}C$ to measure single lap shear strength with universal testing machine.

• Journal of the Korea Concrete Institute
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• v.14 no.1
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• pp.118-125
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• 2002

Hydration is the main reason for the growth of the material properties. An exact parameter to control the chemical and physical process is not the time, but the degree of hydration. Therefore, it is reasonable that development of all material properties and the formation of microstructure should be formulated in terms of degree of hydration. Mathematical formulation of degree of hydration is based on combination of reaction rate functions. The effect of moisture conditions as well as temperature on the rate of reaction is considered in the degree of hydration model. This effect is subdivided into two contributions: water shortage and water distribution. The former is associated with the effect of W/C ratio on the progress of hydration. The water needed for progress of hydration do not exist and there is not enough space for the reaction products to form. The tatter is associated with the effect of free capillary water distribution in the pore system. Physically absorption layer does not contribute to progress of hydration and only free water is available for further hydration. In this study, the effects of chemical composition of cement, W/C ratio, temperature, and moisture conditions on the degree of hydration are considered. Parameters that can be used to indicate or approximate the real degree of hydration are liberated heat of hydration, amount of chemically bound water, and chemical shrinkage, etc. Thus, the degree of heat liberation and adiabatic temperature rise could be determined by prediction of degree of hydration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.94-94
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• 2009

전기 에너지를 기계적 에너지 변환하고 또한, 기계적 에너지를 전기 에너지로 변환할 수 있는 압전 세라믹스는 압전 변압기 (piezoelectric transformer), 초음파모터, 센서등과 같은 응용분야에 넓게 사용되고 있다. 특히, 압전 변압기의 설계와 제조방법에 대해서는 이미 상당히 많은 연구가 수행되어 왔다. 특히, 전원장치에 있어서는 현재 주요부품으로 사용되고 있는 권선형 변압기와 같은 전자 변환기의 대체품으로서 누설손실이 없는 압전세라믹스 소재의 특성을 이용한 압전변압기의 개발과 응용연구가 국내외적으로 활발히 진행 중이다. 하지만 지금 까지 널리 사용된 PZT계 압전 세라믹스는 환경문제에 있어서 문제점을 가지고 있다. $1200^{\circ}C$ 이상에서 소결되는 PZT계열의 압전세라믹스 소재를 사용한 전자부품의 60~70%이상이 PbO로 구성되어 있기 때문에 $1000^{\circ}C$ 부근에서 급격한 휘발특성을 보이는 PbO로 인한 환경오염문제가 대두되고 있다. 압전변압기, 초음파모터등에 사용될 수 있는 무연계 압전재료 중에 PZT 압전소자의 기능을 대체할 만한 물질로는 높은 큐리온도와 우수한 압전특성을 보이는 $(Na,K)NbO_3$세라믹스가 가장 유력한 것으로 알려져 있다. 즉, 압전변압기용 조성 세라믹스는 높은 에너지 변환효율을 위해서 전기기계 결합계수($k_p$)가 커야 되며, 발열에 의한 온도 상승을 억제하기 위하여 기계적 품질계수($Q_m$)가 큰 것이 바람직하다. 또한, 높은 전류를 발생하기 위해서는 유전상수가 커, 압전변압기의 출력측 정전용량을 크게 하여야 한다. 본 연구에서는 무연계 압전세라믹스를 개발하고, 이를 이용한 전력밀도(power density)가 높은 무연계 압전변압기를 제작하여 그에 대한 전기적 특성을 조사하였다. 따라서 본 연구에서는 무연 압전변압기용 압전 세라믹스를 개발하기 위해 뛰어난 압전 및 유전특성을 가진 무연$(Na,K)NbO_3$계 세라믹스를 기본조성으로 하였고, KCN을 복합 첨가하여 볼 변화에 따른 미세구조, 압전 및 유전특성을 조사하고. 가장 우수한 조성으로 비납 압전변압기를 제작하여 전기적특성을 조사하였다.