• Steel and Composite Structures
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• 제11권4호
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• pp.291-305
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• 2011

The new structure consisting of continuous compound spiral hoop reinforced concrete (CCSHRC)column and steel concrete composite (SCC) beam has both the advantages of steel structures and concrete structures. Two types of beam-to-column connections applied in this structural system are presented in this paper. The connection details are as follows: the main bars in beam concrete pass through the core zone for both types of connections. For connecting bar connection, the steel I-beam webs are connected by bolts to a steel plate passing through the joint while the top and bottom flanges of the beams are connected by four straight and two X-shaped bars. For bolted end-plate connection, the steel I-beam webs are connected by stiffened extended end-plates and eight long shank bolts passing through the core zone. In order to study the seismic behaviour and failure mechanisms of the connections, quasi-static tests were conducted on both types of full-scale connection subassemblies and core zone specimens. The load-drift hysteresis loops show a plateau for the connecting bar connection while they are excellent plump for bolted end-plate connection. The shear capacity formulas of both types of connections are presented and the values calculated by the formula agree well with the test results.

• 대한금속재료학회지
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• 제50권8호
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• pp.591-597
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• 2012

This paper presents regularly micro-textured glass surfaces ensuring the superhydrophobic properties in the Cassie-Baxter regime. The proposed surfaces were fabricated simply and efficiently by filling the glass material into a silicon micro-mold with periodic micro-cavities based on a thermal-reflow process, resulting in a successful demonstration of the textured glass surface with periodically-arrayed micro-pillar structures. The static and dynamic wetting properties of the micro-textured glass surfaces were characterized by measuring the static contact angle (SCA) and contact angle hysteresis (CAH), respectively. In addition, the surface wettability was estimated theoretically based on Wenzel and Cassie-Baxter wetting theories, and compared with the experimental ones. Through the experimental and theoretical observations, it was clearly confirmed that the proposed micro-textured glass surfaces showed the slippery superhydrophobic behaviors in the Cassie-Baxter wetting mode.

• Journal of Biosystems Engineering
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• 제17권3호
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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 : $$M=0.123-0.000662T-0.384RH+0.555RH^2$$.

• Journal of Chest Surgery
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• 제10권2호
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• pp.195-204
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• 1977

Dynamic lung compliance was measured in healthy ten young[mean age, 26 years] male and five young[mean age, 25 years] female. Lung volume was integrated of the rate of flow signal which was obtained by using pneumotachograph and differential pressure transducer[PM 5, Statham]. Intrapleural pressure was measured as that of intraesophagel pressure. Esophageal ballon, 15. 5cm in length, 4ml of luminal capacity and made of thin latex, was connected to the polyethylene tube that had 12-14 side holes and was of 1.5mm of ID. Transpulmonary pressure was traced by means of differential pressure transducer[PM 131, Statham] to which connected the esophageal balloon catheter and connection tube from mouth piece. Lung volume and transpulmonary pressure were photographed by cathode ray oscilloscope camera while the subjects were breathing spontaneously. Dynamic lung compliance loop was displayed on single trace monitor and subtraction was performed for the quasi-static hysteresis. Dynamic lung compliance was measured, 1. by plotting the pressure-volume relationship 2. from the subtracted pressure-volume loop. Results were as follows. 1. Dynamic lung compliances measured by plotting of healthy young male and female were $0.202{\pm}0.06$ and $0.190{\pm}0.023L/cm$ $H_2O$ respectively. 2. When measured from subtraction loop, dynamic lung compliance for male and female were $0.327{\pm}0.107$, and $0.27{\pm}0.06L/cm$ $H_2O$ respectively. 3. Dynamic chest wall and total respiratory system compliance were also measured. 4. Dynamic lung compliance by plotting appeared to be essentially same when compared to that of static compliance reported previously from our laboratory, however, that obtained from subtraction loop revealed higher values than the compliances obtained by plotting and that of static compliance.

• Tribology and Lubricants
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• 제37권6호
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• pp.261-272
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• 2021

This study investigates the structural characteristics of oil-free, gas beam foil journal bearings (GBFJBs) for use in high speed motors. Mathematical modeling was carried out, and reaction force modeling for static load was performed to predict the structural characteristics of the GBFJB. Mathematical modeling and reaction force modeling for static load are performed to predict the structural characteristics of GBFJBs. The reaction force of the test bearing against static loads was measured during experiments and compared with the predicted results. The measured experimental data reveal the nonlinear stiffness characteristics of the GBFJB against varying displacement and agree well with the predictions. Dynamic load tests using an exciter allow to identify the vibration characteristics of the GBFJB. Test results show that the vibration displacement, dynamic force, and acceleration measured on the test bearing are most dominant at the applied dynamic load (synchronization) frequency. Futhermore, the test results show that the hysteresis area recorded during the dynamic tests increases with the excitation amplitude and frequency, and that the beam stick phenomena occurr at high excitation frequencies. The single degree of freedom (DOF) vibration model aids to identify the stiffness and damping coefficient of the GBFJB, which decrease as the excitation frequency increases.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.28-31
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• 1990

In perpendicular magnetic recording system, the magnetic recording and reproduction characteristics of isolated transition of magnetization is simulated in this paper. The recording system which is magneto-static system is analyzed using two-dimensional finite element method and the characteristics of hysteresis of recording media is considered. The results show that the optimizing current is exist in magnetic recording system.

• 한국정밀공학회지
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• 제31권4호
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• pp.353-358
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• 2014

This paper reports a simple, yet effective 1-step surface modification method for stainless steel. Electrochemical etching in dilute Aqua Regia forms hierarchical micro and nanoscale structure on the surface. The surface becomes highly hydrophobic (${\sim}150^{\circ}$) as a result of the etching in terms of static contact angle (CA). However the liquid drops easily pinned on the surface because of high contact angle hysteresis (CAH), which is called a "petal effect": The petal effect occur because of gap between surface microstructures, despite of intrinsic hydrophobicity of the base material. The pore size and period of surface structure can be controlled by applied voltage during the etching. This method can be applied to wide variety of industrial demand for surface modification, while maintaining the advantageous anti-corrosion property of stainless steel.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1055-1059
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• 1992

Instantaneous Voltage Control of inverter for uninterruptible power supply(UPS) is presented. In order to improve the transient response, the authors propose a control scheme based on a double regulation loop with sinusoidal hysteresis band. And also, using 8097 single chip microprocessor, software synchronization and static switch control scheme is impremented with minimal hard ware structure.

• 한국정밀공학회지
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• 제9권1호
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• pp.29-33
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• 1992

A non-contact torque sensor was developed using amorphous alloy. The change of maixmum magnetic induction of C0-based amorphous alloy under the tensile and compressive stress was proportional to applied torque. For the construction of the torque sensor, a glass fiber reinforced-epoxy rod was used as shaft. The amorphous strips were attached on the epoxy shaft in the direction of $+45^{\circ}$and $-45^{\circ}$. The magnetizing coil and 2 sensing coil was installed. The static and dynamic test was carried out. The linearity and sensor hysteresis of the torque sensor was less than 1%.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.99-105
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• 2008

Multi-leaf springs are widely used for a major suspension component in many commercial vehicles. The modeling technique of multi-leaf springs is one of the most difficult problems in suspension modeling as the elements have complicated nonlinear characteristics such as a hysteresis behavior due to the friction. In this paper, hysteretic characteristics with the static and dynamic test are modeled and are simulated with three links and joints in MSC.ADAMS. Simulation results showed good agreements with test results. Using this methodology, it is expected that dynamic characteristics of suspension system with multi-leaf spring can be more accurately evaluated in vehicle dynamics.