• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.391-401
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• 2000

Flow through compliant tubes with linear taper in wall thickness is numerically simulated by finite element analysis. For verification of the numerical method, flow through a compliant stenotic vessel is simulated and the results are compared to the existing experimental data. Steady two-dimensional flow in a collapsible channel with initial tension is also simulated and the results are compared with numerical solutions from the literature. Computational results show that as cross-sectional area decreases with the reduction in downstream pressure, flow rate increases and reaches the maximum when the speed index (mean velocity divided by wave speed) is near the unity at the point of minimum cross-section area, indicating the flow limitation or choking (flow speed equals wave speed) in one-dimensional studies. for further reductions in downstream pressure, flow rate decreases. The flow limitation or choking consist of the main reasons of waterfall effect which occurs in the airways, capillaries of lung, and other veins. Cross-sectional narrowing is significant but localized. When the ratio of downstream-to-upstream wall thickness is 2, the area throat is located near the downstream end. As this ratio is increased to 3, the constriction moves to the upstream end of the tube.

• The Korean Journal of Pharmacology
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• v.20 no.2
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• pp.7-14
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• 1984

In pithed rats, rising in diastolic blood pressure by clonidine, when intravenously injected, is expressed as the postsynaptic action, and inhibitory action on electrical stimulation-induced tachycardia by clonidine is expressed as the presynaptic inhibitory action. In this study it was aimed to observe the inhibitory effect of imipramine caused by a single and chronic administration on both postsynaptic and presynaptic action of clonidine in pithed rats, and discussed in relation with the mechanism of antidepressant action of imipramine. 1) A rise of diastolic blood pressure by clonidine was not antagonized by prazosin, but by both phentolamine and piperoxan. 2) The inhibition by clonidine of tachycardia which was induced by electrical stimulation was also antagonized by phentolamine and piperoxan, but not by prazosin. 3) The increase in diastolic blood pressure in response to clonidine was inhibited by both a single or chronic administration with imipramine (20 mg/kg). It was more pronounced in the latter. 4) The inhibitory action of clonidine on the tachycardia was markedly inhibited by both types of administration with imipramine, between which there showed little difference. It is concluded that the presynaptic ${\alpha}_2-adrenoceptor$ is rather sensitively affected by a single administration with imipramine, and a long-term imipramine treatment may inhibit both pre- and postsynaptic ${\alpha}_2-adrenoceptors$, simultaneously. Furthermore, it was seemed unlikely that these results provide the evidence :to support the fact that the subsensitivity of presynaptic ${\alpha}_2-adrenoceptor$ may be the mechanism of action of tricyclic antidepressant.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.792-795
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• 2008

AGT system is a kind of light railway train. AGT system use of concrete track and rubber tire, so it can be reduce the noise and vibration, compare to the normal train system. And, the dynamic responses of normal bridge are influenced by the dynamic characteristics of bridge, the speed of vehicle and the surface roughness of railway. But the AGT system bridge is influenced not only the above facts but also the guiderail unevenness, because, AGT vehicle steered by guiderail. So, in this study, optimized service condition is suggested for the design and operation of AGT system, by the means of experimental study. The experiments are executed for PSC bridge with length of 30m, at the AGT test line in Kyongsan. The test results are compared and investigated according to the prominence. In the test result, the guiderail prominence influenced on the dynamic response of bridge. It shows a increase as compared with no guiderail prominence in the dynamic response value acceleration, displacement, stain.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.378-385
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• 2017

This study investigated the design of a snap fit, which is widely used for fastening plastic parts. We analyzed the assembly mechanism of a lock snapfit, measured the assembly force and separation force based on the design of experiments, and derived a regression equation through an analysis of variance. The response surface methodology was also used. Polybutylene terephthalate was used to fabricate specimens, and the assembly force and separation force were measured using a micro-tensile tester. The length, width, thickness, and interference were considered as factors. A second-order regression model was used to derive the regression equation. The assembly force decreased with increasing length and width, but it increased with increasing thickness and interference. The finite element method was used to analyze the assembly mechanics. The width decreased the assembly force by increasing the ductility. The influences of the factors for low assembly force and high release force were shown to be opposite to each other. It was necessary to design a structure that minimized the assembly force while maintaining an appropriate level of separation force.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.765-774
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• 2011

The purpose of this study is to provide informative statistics which can be used for effective Diabetes Management Programs. We collected and analyzed the data of 666 diabetic people who had participated in Korean National Health and Nutrition Examination Survey in 2007 and 2008. Group classification on management behavior of Diabetic Mellitus is based on the K-means clustering method. The Decision Tree method and Multiple Regression Analysis were used to study factors of the management behavior of Diabetic Mellitus. Diabetic people were largely classified into three categories: Health Behavior Program Group, Focused Management Program Group, and Complication Test Program Group. First, Health Behavior Program Group means that even though drug therapy and complication test are being well performed, people should still need to improve their health behavior such as exercising regularly and avoid drinking and smoking. Second, Focused Management Program Group means that they show an uncooperative attitude about treatment and complication test and also take a passive action to improve their health behavior. Third, Complication Test Program Group means that they take a positive attitude about treatment and improving their health behavior but they pay no attention to complication test to detect acute and chronic disease early. The main factor for group classification was to prove whether they have hyperlipidemia or not. This varied widely with an individual's gender, income, age, occupation, and self rated health. To improve the rate of diabetic management, specialized diabetic management programs should be applied depending on each group's character.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.1023-1026
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• 2006

There are some cases in trouble with monitoring emergency patient by existing electrode sensor in measuring instrument in home and hospital etc. And there are problem to measure because of coming down electrode in emergency car or vessel of shaking and fat, humidity of patient. In this study, it has designed band-type for patient to put on the breast easily and go around anywhere freely putting band electrode on his body. Gold has used as electrode material in this electrocardiogram because of its excellent electronic resistance peculiarity and no trouble with skin. And it is able to monitor multi-body-signal by additional design of periphery temperature. There are good results of body signal transmission in the breast or the rib, and get a little body signal in abdomen. We get a result it is better case of gold than usual electrode on signal detection, and know usual electrode was disposable, but we have more correct result from gold electrode sensor, being semi-permanent ana. great contact ability even if movement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.394-400
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• 2014

In this study, we fabricated ITZO thin films on glass substrates with various RF power from 30 to 60W and investigated the electrical, optical and structural properties. ITZO thin film deposited at 50W exhibited the largest figure of merit ($10.52{\times}10^{-3}{\Omega}^{-1}$) and then its resistivity and sheet resistance were $3.08{\times}10^{-4}{\Omega}-cm$ and $11.41{\Omega}/sq.$, respectively. As results of optical characterization, average transmittance of all ITZO thin films were over 80%. ITZO thin films had amorphous structure regardless of the RF power. The FESEM and AFM results showed that all ITZO thin films have a very smooth surface having no cracks and defects and the film deposited at 50W exhibit the smallest surface roughness of 0.254nm. We found that a amorphous ITZO thin film is a very promising material for replacing ITO in the next display device such as OLED.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2497-2502
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• 2014

The 5 wt.% Ga-doped zinc oxide (GZO) thin films were fabricated on PES substrates with various RF power 50~80 W by using RF magnetron sputtering in order to investigate the optical and electrical properties of GZO thin films. The XRD measurement showed that GZO thin films exhibit c-axis orientation. At a RF power of 70W, the GZO thin film showed the highest (002) diffraction peak with a Full-Width-Half-Maximum (FWHM) of $0.44^{\circ}$. AFM analysis showed that the lowest surface roughness (0.20 nm) was obtained for the GZO thin film fabricated at 70 W of RF power. The electrical property indicated that the minimum resistivity ($6.93{\times}10^{-4}{\Omega}{\cdot}cm$) and maximum carrier concentration ($7.04{\times}10^{20}cm^{-3}$) and hall mobility ($12.70cm^2/Vs$) were obtained in the GZO thin film fabricated at 70W of RF power. The optical transmittance in the visible region was higher than 80 %, regardless of RF power. The optical band-gap showed the slight blue-shift with increased in carrier concentration which can be explained by the Burstein-Moss effect.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.5
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• pp.1213-1218
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• 2013

In this study, Ga-doped ZnO (GZO) thin films were fabricated on transparent sapphire substrate by RF magnetron sputtering method and then investigated the effect of various substrate temperature on the electrical, optical properties and characteristic of crystallization of the GZO thin films. The electrical property indicated that the lowest resistivity ($4.18{\times}10^{-4}{\Omega}cm$), the highest carrier concentration ($6.77{\times}10^{20}cm^{-3}$) and Hall mobility ($22cm^2/Vs$) were obtained in the GZO thin film fabricated at $300^{\circ}C$. And for this condition, the highest c-axis orientation and (002) diffraction peak which exhibits a FWHM of $0.34^{\circ}$ were obtained. From the results of AFM measurements, it is known that the highest crystallinity is observed at $300^{\circ}C$. The transmittance spectrum in the visible range was approximately 80 % regardless of substrate temperature. The optical band-gap showed the blue-shift as increasing the substrate temperature to $300^{\circ}C$, and they are all larger than the band gap of bulk ZnO (3.3 eV). It can be explained by the Burstein-Moss effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4267-4275
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• 2015

Prefabricated houses are fabricated at the factory for approximately 60 to 80% of the entire construction process, and assembled in the field. In the process of transporting and lifting, internal and external finishes of the unit module are concerned about damages. The purpose of this study is to improve the fixing equipment by analyzing load behavior. The improved fixing equipment would minimize the deformation of internal and external finishes. In order to develop the improved fixing equipment, transporting load on the fixing equipment is analyzed using Monte Carlo simulations, and structural performance is verified by the non-linear finite element analysis. Statistical analysis shows load distribution of unit module is similar with extreme value distribution. Based on the statistical analysis and Monte Carlo simulation, the maximum transporting load is 28.9kN and 95% confidence interval of transporting load is -1.22kN to 9.5kN. The nonlinear structural analysis shows improved fixing equipment is not destructed to the limit load of 35.3kN and withstands the load-bearing in the 95% confidence interval of transporting load.