• Journal of The Korean Society of Integrative Medicine
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• v.3 no.3
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• pp.59-71
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• 2015

Purpose : This study examines the effect of vibration exercise grafting PNF patterns for 6 weeks on upper body stability and equilibrium for seniors having fifteen or over of MMSE-K. Method : A total of 10 senior citizens participated in this study. Each participant performed PNF patterned exercises using vibration sports equipment for 30 minutes, once static a week, for six weeks. We measured trunk stability and balance degree before and after the six-week exercise program. Motor Assessment Scale (MAS) was used to measure trunk stability, while Functional Reach Test (FRT) and Timed Up and Go (TUG) was used to measure balance degree. The collected data was processed using paired t-test to confirm the difference between pre-program conditions and post-program conditions. Results: The results of our study show that post-program trunk stability measurements increased when compared to pre-program data; however, this increase was not statistically significant. pre and post-measurements for satatic balance and dynamic balance were statistically unchanged. Conclusion: Due to limitations in the number of participants, the procedural design of this experiment, and the limited amount of time participants actually controlled, this study failed to produce statistically significant results. However, further study should be conducted using a systematically implemented exercise program to show support for exercising with flexi-bar as an effective program for the elderly.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.1
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• pp.9-16
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• 2018

When designing a reinforced concrete member using nonlinear finite element analysis results, the bending moment at the critical section should be calculated. In this paper, a bending moment calculation method using the results of reinforced concrete finite element analysis(FEA) using continuum elements is presented and the optimum element size according to the order of the displacement function of the finite element is proposed. The bending moments calculated by integrating the stresses from the FEA are compared with the bending moments calculated using the static equilibrium conditions. In the method of integrating the stress, both the stress due to the reinforcing bar and the stress of the concrete are considered. In addition, various factors affecting the accuracy of the stresses calculated by the FEA were analyzed and the influence of the displacement function and the element size was verified. If the purpose of the analysis is to roughly observe the behavior of the members, it is appropriate to use the first order displacement function and the element size should be about 25% of the section height of the analytical model. When the bending moment of a member with high accuracy is required, it is suggested that the secondary displacement function be used and the element size be 12.5%.

• Environmental and Resource Economics Review
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• v.26 no.2
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• pp.257-286
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• 2017

This paper estimates the effects of imaginary repeated increases in excise duties on fuel oil consumption and on their income redistribution according to changes in consumer price index, if the inflation indexation system was introduced right after the second Energy Tax Reform ended in July, 2007 in Korea. In fact, nominal excise rates have not been adjusted since 2007. As a result, the real excise rates on fuel oils have been diminished inversely proportional to the consumer price index. Own- and cross-price elasticities of fuel oils such as gasoline and diesel oil are estimated under the general equilibrium framework based on the linear expenditure system. Counterfactual analyses through microsimulation in a static model are adopted to estimate the effects of introducing inflation indexation into the fuel tax in 2007 when the second Energy Tax reform ended on the fuel consumption and income redistribution in 2014. Microsimulations suggest that its introduction could have reduced the consumption of gasoline and diesel oil by 8.8% and 5.4%, respectively, ending up with increased excise revenue by 11.9%. The revenue increase in spite of decreased consumption is mainly because their demands are price inelastic. It could also have increased positive income redistributive effect by 0.01%p (from 0.12% to 0.13%), which is measured in terms of percentage decrease in Gini coefficient. In other words, the fuel excise on the two fuel oils decreased by 0.13% the Gini coefficient of before and after fuel tax income in 2014. This implies that the inflation indexation could have enlarged the income redistributive effect up to 0.13% in 2014, if it is introduced in 2007.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.4
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• pp.106-113
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• 1997

Dynamic loading of structures often causes excursions of stresses well into the inelastic range, and the influence of the geometric changes on the dynamic response is also significant in many cases. Therefore, both material and geometric nonlinearity effects should be considered in case that a dynamic load acts on the structure. A structure in a nuclear power plant is a structure of importance which puts emphasis on safety. A nuclear container is a pressure vessel subject to internal pressure and this structure is constructed by a reinforced concrete or a pre-stressed concrete. In this study, the material nonlinearity effect on the dynamic response is formulated by the elasto-viscoplastic model highly corresponding to the real behavior of the material. Also, the geometrically nonlinear behavior is taken into account using a total Lagrangian coordinate system, and the equilibrium equation of motion is numerically solved by a central difference scheme. The constitutive relation of concrete is modeled according to a Drucker-Prager yield criterion in compression. The reinforcing bars are modeled by a smeared layer at the location of reinforcements, and the steel layer model under Von Mises yield criteria is adopted to represent an elastic-plastic behavior. To investigate the dynamic response of a nuclear reinforced concrete containment structure, the steel-ratios of 0, 3, 5 and 10 percent, are considered. The results obtained from the analysis of an example were summarized as follows 1. As the steel-ratio increases, the amplitude and the period of the vertical displacements in apex of dome decreased. The Dynamic Magnification Factor(DMF) was some larger than that of the structure without steel. However, the regular trend was not found in the values of DMF. 2. The dynamic response of the vertical displacement and the radial displacement in the dome-wall junction were shown that the period of displacement in initial step decreased with the steel-ratio increases. Especially, the effect of the steel on the dynamic response of radial displacement disapeared almost. The values of DMF were 1.94, 2.5, 2.62 and 2.66, and the values increased with the steel-ratio. 3. The characteristics of the dynamic response of radial displacement in the mid-wall were similar to that of dome-wall junction. The values of DMF were 1.91, 2.11, 2.13 and 2.18, and the values increased with the steel-ratio. 4. The amplitude and the period of the hoop-stresses in the dome, the dome-wall junction, and the mid-wall were shown the decreased trend with the steel-ratio. The values of DMF were some larger than those of the structure without steel. However, the regular trend was not found in the values of DMF.

• Journal of Biosystems Engineering
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• v.17 no.3
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• pp.247-259
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• 1992

This study intended to measure the desorption and adsorption EMC of four years old Peeled ginseng, Unpeeled ginseng and Taegeuk ginseng under various conditions$20^{\circ}C$, $30^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$) and five levels of relative humidity from 31% to 88%) by the static method. Four widely used EMC models were selected and evaluated. Also the empirical model was evaluated. The results are summarized as follows ; 1) EMC difference between ginseng size was not found but found between ginseng species. EMC difference between Peeled ginseng and Unpeeled ginseng was not found. EMC of Peeled ginseng and Unpeeled ginseng was higher than that of Taegeuk ginseng. 2) The hysteresis, which is difference between desorption and adsorption EMC, was found. Desorption EMC was higher than adsorption EMC. The hysteresis at the same temperature decreased as relative humidity increase. The difference of hysteresis between Peeled ginseng and Unpeeled ginseng was not large and the hysteresis of Taegeuk ginseng was smaller than those of other species. 3) Among the selected models, Henderson model was the best to predict the adsorption EMC of White ginseng(Peeled and Unpeeled ginseng), and Oswin model was the best to predict the desorption EMC of White ginseng and the desorption and adsorption EMC of Taegeuk ginseng. The models are as follows ; (a) White ginseng(Peeled and Unpeeled ginseng) ${\circ}$ Desorption EMC(Oswin model) : $$M=(0.1272-0.0007420T){\cdot}[RH/(1-RH)]^{(0.4164+0.001368T)}$$ ${\circ}$ Adsorption(Henderson model) : $$1-RH={\exp}[-0.0003480T_k\;{M_o}^{0.9231}]$$ (b) Taegeuk ginseng ${\circ}$ Desorption EMC(Oswin model) : $$M=(0.1051-0.0008439T)[RH/(1-RH)]^{(0.4553+0.003425T)}$$ ${\circ}$ Adsorption EMC(Oswin model) : $$M=(0.08247-0.0007559T){\cdot}[RH/(1-RH)]^{(0.5760+0.005540T)}$$ 4) The developed empirical models could predict the desorption and adsorption EMC for White and Taegeuk ginseng more precisely than selected models. The empirical models are as follows ; (a) White ginseng(Peeled and Unpeeled ginseng) ${\circ}$ Desorption EMC : $$M=0.124-0.000647T-0.216RH+0.373RH^2$$ ${\circ}$ Adsorption EMC : $$M=0.0879-0.000663T-0.197RH+0.399RH^2$$. (b) Taegeuk ginseng ${\circ}$ Desorption EMC : $$M=0.159-0.000728T-0.429RH+0.565RH^2$$ ${\circ}$ Adsorption EMC : $$M=0.123-0.000662T-0.384RH+0.555RH^2$$.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.91-105
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• 2016

Carbon Nanotube Field-Effect Transistors (CNTFETs) have been studied as candidates for post Si CMOS owing to the better electrostatic control and high mobility. To enhance the immunity against short - channel effects (SCEs), the novel channel and gate engineered architectures have been proposed to improve CNTFETs performance. This work presents a comprehensive study of the influence of channel and gate engineering on the CNTFET switching, high frequency and circuit level performance of carbon nanotube field-effect transistors (CNTFETs). At device level, the effects of channel and gate engineering on the switching and high frequency characteristics for CNTFET have been theoretically investigated by using a quantum kinetic model. This model is based on two-dimensional non-equilibrium Green's functions (NEGF) solved self - consistently with Poisson's equations. It is revealed that hetero - material - gate and lightly doped drain and source CNTFET (HMG - LDDS - CNTFET) structure can significantly reduce leakage current, enhance control ability of the gate on channel, improve the switching speed, and is more suitable for use in low power, high frequency circuits. At circuit level, using the HSPICE with look - up table(LUT) based Verilog - A models, the impact of the channel and gate engineering on basic digital circuits (inverter, static random access memory cell) have been investigated systematically. The performance parameters of circuits have been calculated and the optimum metal gate workfunction combinations of ${\Phi}_{M1}/{\Phi}_{M2}$ have been concluded in terms of power consumption, average delay, stability, energy consumption and power - delay product (PDP). In addition, we discuss and compare the CNTFET-based circuit designs of various logic gates, including ternary and binary logic. Simulation results indicate that LDDS - HMG - CNTFET circuits with ternary logic gate design have significantly better performance in comparison with other structures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1119-1127
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• 2010

In this paper, the design and nonlinear simulation of a multistable electromagnetic microactuator, which provides four stable equilibrium positions within its operating range, have been discussed. Quadstable actuator motion has been made possible by using both X- and Y-directional bistable structures with snapping curved beams. Two pairs of the curved beams are attached to an inner frame in both X- and Y-directions to realize independent bistable behavior in each direction. For the actuation of the actuator at the micrometer scale, an electromagnetic actuation method in which Lorentz force is taken into consideration was used. By using this method, micrometer-stroke quadstability in a plane parallel to a substrate was possible. The feasibility of designing an actuator that can realize quadstable motion by using the electromagnetic actuation method has been thoroughly clarified by performing nonlinear static and dynamic analyses and electrothermal coupled-field analysis of the multistable microactuator.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.38-45
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• 2009

In this study, interfacial properties were measured for imidazoline type cationic surfactant system which has been widely used as a fabric softener, a dispersant, an anti-static agent, a bleach activator, and an emulsifier. The CMC of imidazoline surfactant was near $6{\times}10^{-5}mol/L$ and the surface tension at CMC was about 32 mN/m. It was found that surface tension was not affected by surfactant concentration but decreased with an increase in pH. The interfacial tension between 1 wt% aqueous solution and n-dodecane was shown to be about 0.01 mN/m and equilibration time was not affected by pH. Phase behavior experiment in a binary aqueous surfactant system showed that only micellar solution of $L_1$ phase was found under conditions of temperature and pH investigated during this study. Only a two-phase region consisting of lower-phase microemulsion in equilibrium with excess oil phase existed under the same conditions, when oil was added to the binary surfactant system. The foam stability measured with 1 wt% surfactant solution increased with pH, which is consistent with surface tension measurement result. QCM(quartz crystal microbalance) measurement showed that surfactant adsorption increased with surfactant concentration but decreased with pH. According to the friction measurement, best fabric softening effect by imidazoline surfactant system was found under alkali conditions.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.189-193
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• 1981

An apparatus for continuous measurements of sorption isotherm of dried food was manufactured to shorten the time required for equilibration. The apparatus was so designed that the temperature, air velocity and relative humidity in the experimental chamber could be controlled. The use of dynamic stream of conditioned air with a velocity of 0.2m/sec, instead of static atmosphere, allowed a faster equilibration of dried filefish muscle at $25^{\circ}C$. The mean time necessary for the equilibration of dried filefish muscle at the water activity of a given state to a higher water activity was about 45 hours. The monolayer moisture content of dried filefish muscle calculated from BET-equation was 0.092 kg water /kg dry matter at $25^{\circ}C$.

• Korean Journal of Environmental Agriculture
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• v.22 no.4
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• pp.284-289
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• 2003

Titanium mesoporous materials have received increasing attention as a new photocatalyst in the field for photocatalytic degradation of organic compounds. The photocatalytic degradation of chlorothalonil by mesoporous titanium oxo-phoswhate (Ti-MCM) was investigated in aqueous suspension for comparison with $TiO_2$, (Degussa, P25) using as an effective photocatalyst of organic pollutants. Mesoporous form of titanium Phosphate has been prepared by reaction of sulfuric acid and titanium isopropoxide in the presence or n-hexadecyltrimethylammonium bromide. The XRD patterns of Ti-MCM are hexagonal phases with d-spacings of 4.1 nm. Its adsorption isotherm for chlorothalonil reached at reaction equilibrium within 60 min under dark condition with 28% degradation efficiency. The degradation ratio of chlorothalonil after 9 hours under the UV radiation condition (254 nm) exhibited 100% by Ti-MCM and 88% by $TiO_2$. However, these degradation kinetics in static state showed a slow tendency compared to that of stirred state because of a low contact between titanium matrices and chlorothalonil. Also, degradation efficiency of chlorothalonil was increased with decreasing initial concentration and with increasing pH of solution. As results of this study, it was clear that mesoporous titanium oxo-phosphate with high surface area and crystallinity could be used to photo- catalytic degradation of various organic pollutants.