• Korean Journal of Community Nutrition
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• v.22 no.5
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• pp.426-440
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• 2017

Objectives: The valid assessment of food and nutrients intakes using appropriate dietary intake method is necessary to improve the nutritional status of the hemodialysis (HD) patients. This study was conducted to compare the method between newly developed, semi-quantitative food frequency questionnaire (Semi-FFQ) and 7-day dietary records (7-DRs) for hemodialysis patients. Methods: We conducted both methods on 53 maintenance HD patients in two university hospitals. We calibrated the frequency, portion size and daily intake of 47 food items reported in Semi-FFQ. The food and nutrients intake was compared and the correlation of the two methods was analyzed. Also each nutrient intake was compared to recommended dietary allowance for Korean (KDRIs) and recommended nutrient reference value for HD patients. Results: Energy and energy-yielding nutrients intakes were significantly higher in the two methods (p<0.01). These support the possible reliability between Semi-FFQ and 7-DRs that is similar with regard to most mineral and vitamin intakes. Thus, the Semi-FFQ used in this study for the assessment of nutrient intakes of HD patients can be reliable for the assessment of the nutrient intake along with the 7-DRs. The correlation coefficients were higher for foods consumed daily, such as steamed rice, meat and chicken, bean, egg, milk, coffee and alcohol than for those of foods eaten rarely (p<0.01). Conclusions: The Semi-FFQ used in this study can be a reliable tool for the assessment of the HD patients' nutrient intake along with the 7-DRs, despite its limitations.

• Environmental Engineering Research
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• v.19 no.3
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• pp.261-268
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• 2014

Leachate quality and methane emission from pilot-scale lysimeters operated under semi-aerobic and anaerobic conditions were monitored for 650 days. Two semi-aerobic lysimeters were filled with un-compacted and compacted municipal solid wastes whereas two anaerobic lysimeters containing compacted wastes were operated with leachate storage at 50% and 100% of waste height, respectively. Despite having high moisture in wastes and operating under tropical rainfall events, leachate stabilization in semi-aerobic lysimeters took place much faster resulting in BOD reduction by 90% within 60 days, significantly shorter than 180-210 days observed in anaerobic lysimeters. Nitrogen concentration in leachate from semi-aerobic lysimeter could be reduced by 90%. In term of gas emission, semi-aerobic lysimeter with un-compacted wastes had much lower methane emission rate of $2.8g/m^2/day$ compare to anaerobic lysimeters ($62.6g/m^2/day$) through seasonal fluctuation was observed. Nevertheless, semi-aerobic lysimeter with waste compaction has similar performance to anaerobic lysimeter.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.2
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• pp.70-85
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• 2006

The supersonic flutter suppression of a cantilevered plate wing is studied with the finite element method and the quasi-steady aerodynamic theory. We suppress wing flutter by using piezoelectric materials and electric devices. Two approaches to flutter suppression using piezoelectric materials are presented; an energy-recycling semi-active approach and a negative capacitance approach. To assess their flutter suppression performances, we simulate flutter dynamics of the plate wing to which piezoelectric patches are attached. The critical dynamic pressure drastically increases with our flutter control using a negative capacitor.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.56-62
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• 2000

Semi-solid forming process has some advantages such as successful manufacturing of high quality components with less inner defects suitable for less machining high productivity and energy-saving effect. the thixotropic behavior(solid-like in the unperturbed state and liquid-like during shearing) has been the basis for the semi-solid forming process. The main focus of this article is the investigation of the effect of T6 heat treatment and alloying elements on the mechanical properties in the semi-solid formed products using thixotropic hypoeutectic (A357 and ALTHIX 86S) and hypereutectic(A390) materials. The new methods to produce semi-solid formed components with high quality are also proposed and discussed in terms of a die design and the development of a lubricant.

• Land and Housing Review
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• v.11 no.1
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• pp.87-94
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• 2020

To implement the planning of zero-energy buildings, their energy performance must be improved, and renewable energy applications must also be included. To accelerate the use of renewable energies in such buildings, BIPVs should be actively used in windows and on roofs. Window-type BIPVs are being developed in various forms depending on the size, composition, area ratio of the window, specification of glass, and so on. To analyze the applicability of various solar cells as window-type BIPVs, in this study, we evaluated their applicability, at the current development level, by analyzing the indoor illuminance, heat gain and heat loss; the cooling, heating, and lighting energy levels; and the generation performance of the various solar cells. To enhance the future applicability of window type BIPV, we analyze the overall energy performance of the building, according to changes in visible light transmittance and generation efficiency. The main research results are as follows. The area ratios above the standard illuminance, based on the window type and according to the VLT, were in order of low-e glazing, a-Si window, DSSC window, and c-Si window. The heat gain of the semi-transparent solar cell winodw was remarkably low. The energy consumption of buildings was highest in the order of c-Si window, DSSC window, a-Si window, and clear low-e window. However, in the case of including the power generation performance of the solar cell, the energy consumption was found to be high in order of DSSC window, c-Si window, a-Si window, and clear low-e window. In the future, if a window-type BIPV is developed, we believe that improvement in power generation performance and improvement in visible light transmittance will be needed.

• Journal of Power System Engineering
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• v.6 no.2
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• pp.82-87
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• 2002

For the dynamic behavior evaluation of a semi-active vibration control system, it is very important to use an accurate mathematical model for the hydraulic damper applied to the control system. In this study, a mathematical model for a symmetric type hydraulic damper was suggested. In this model, the effects of gas volume and oil temperature variation on the bulk modulus of oil were considered. The dynamic behavior of the damper was investigated by experiments and simulations. It was confirmed that the pressure variation, damping force, and mean pressure variation could be estimated with comparatively good precision by the suggested mathematical model. Moreover, it was shown that excessive pressure rise can be generated by the oil expansion due to the heat energy transformed from the exciting energy of the damper for a short period of the damper operation.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.703-707
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• 1989

The ignition of solid particle under strong convective heating has been investigated by applying an asymptotic analysis to a semi-infinite body for varying values of gas recovery temperature and convective heat transfer coefficient. It was found that if the scale of the reaction zone is much smaller than the characteristic length of the body size, then infinite body theory can be used to estimate the ignition delay time. Furthermore, the convective heat transfer coefficient was found to have more influence on predicting the ignition delay times of particle exposed to an incident shock wave rather than the gas recovery temperature.

• Macromolecular Research
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• v.10 no.2
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• pp.60-66
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• 2002

The morphology, dynamic mechanical behavior and fracture behavior of polyetherimide (PEI)/dicyanate semi-interpenetrating polymer networks (semi-IPNs) with a morphology spectrum were analyzed. To obtain the morphology spectrum, we disported PEI particles in the procured dicyanate resin containing 300 ppm of zinc stearate catalyst. The semi-IPNs exhibited a morphology spectrum, which consisted of nodular spinodal structure, dual-phase morphology, and sea-island type morphology, in the radial direction of each dispersed PEI particle due to the concentration gradient developed by restricted dissolution and diffusion of the PEI particles during the curing process of the dicyanate resin. Analysis of the dynamic mechanical data obtained by the semi-IPNs demonstrated that the transition of the PEI-rich phase was shifted toward higher temperature as well as becoming broader because of the gradient structure. The semi-IPNs with the morphology spectrum showed improved fracture energy of 0.3 kJ/$m^2$, which was 1.4 times that of the IPNS having sea-island type morphology. It was found that the partially introduced nodular structure played a crucial role in the enhancement of the fracture resistance of the semi-IPNs.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.6
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• pp.574-580
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• 2013

At high frequencies, the statistical approach such as statistical energy analysis(SEA) and energy flow analysis(EFA) has been applied for estimation of vibroacoustic responses of various built-up structures. The energy coupling relationship between finite coupled structures is required to estimate vibrational energetics of built-up structures. Mindlin plate theory includes the rotatory inertia and shear deformation effects which are dominant as frequency increases. In this paper, the wave transmission analysis is successfully performed for EFA of co-planar coupled Mindlin plates.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.473-478
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• 2005

Active suspension system improves ride quality with optimized suspension force, generated by electric, hydrolic or pneumatic power and controlled by micro-processor under various operation condition of train, while Semi-Active susepsion system provides optimized and controlled characteristics of suspensions such as damping coefficient without external energy. The benefits fo Semi-Active suspension are no required power source and to be made compact with lower cost. Train with narrow gauge could be more unstable than one for normal or wide gauge, and it could be more vibrated than others one by external force such as aerodynamic force and track irregularity. So, the reduced ride quality could be improved with appling with Semi-active suspension system. In this report, the Semi-Active suspension system for narrow gauge train shall be proposed and to prepare the Roller Rig test of this train, integration of system, development of control algorithm and confirmation of its performance with simulation tool would be taken.