• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1997.11a
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• pp.228-232
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• 1997

The special interest should be paid to the analysis of the influences of positive emotions in terms of their possible effects on the dyanmics of autonomic. recovery after the negative affective stimualtion. Taking into account emotion-specific autonomic response patterning and dissociation of parameters of autonomic arousal during experience of both positive and negative emotional states, this problem seems a challenging one. In present study several autonomic parameters were analyzed altogether, namely inedices of electrodermal activity, heart rate and respitation rate during consecutive combination or both IAPS-based visual affective and auditory stimulation. The aim of the study was analysis of patterns of electrodermal and cardiorespiratory responses during emotional states evoked by negative affective visual stimulation followed by positive or neutral auditory one with intention to identify if the latter is able to facilitate post-stress recovery and enhance restoration of pre-arousal levels. The main orientation was dirdcted towards the further application of experimentally induced comfort emotions for dampening the negative consequences of exposure to stressful stimuli.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.04a
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• pp.44-56
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• 1998

Effects of the music and white noise on recovery of the autonomic and cortical responses evoked by aversive visual stimulation were analyzed in 20 subjects. It was suggested that the music is able to exert modulatory influence on the physiological activity resulted from exposure to unpleasant IAPS based stimuli. Spectral power of DDG, heart rate(HR)respiration rate (RSR) and electrodermal activity(EDA)were recorded and analyzed for each experimental condition. It was observed HR and RSR deceleration, increased EDA and electrocortical activation expressed in decreased alpha power and increase of delta activity ao occipital and frontal areas. Obtained results suggest that audutory stimulation both with pleasant and sad music lead to restoration of pre-stimulation activation levels of most physiological parameters during listenning to music and in post-stimulation period. White noise evoked short-term physiological responses typical for orienting reaction and quite distinct from changes produced by music. Available data to differentiate effeces among pleasant and sad music, due toqualitative similarities of physilolgical patterns, but suppert an assumption that music is capable to facilitate the process of recovery of physilolgical responses elicited by visual stimulation of negative valence, thus positively modulate post-stress state.

• Journal of Power Electronics
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• v.19 no.3
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• pp.645-654
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• 2019

In this paper, a new high step up DC/DC converter with a modified super-lift technique is presented. The coupled inductor technique is combined with the super-lift technique to provide a tenfold or more voltage gain with a proper duty cycle and a low turn ratio. Due to a high conversion ratio, the voltage stress on the semiconductor devices is reduced. As a result, low voltage ultra-fast recovery diodes and low on resistance MOSFET can be used, which improves the reverse recovery problems and conduction losses. This converter employs a passive clamp circuit to recycle the energy stored in the leakage inductance. The proposed convertor features a high conversion ratio with a low turn ratio, low voltage stress, low reverse recovery losses, omission of the inrush currents of the switch capacitor loops, high efficiency, small volume and reduced cost. This converter is suitable for renewable energy applications. The operational principle and a steady-state analysis of the proposed converter are presented in details. A 200W, 30V input, 380V output laboratory prototype circuit is implemented to confirm the theoretical analysis.

• Corrosion Science and Technology
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• v.20 no.2
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• pp.69-76
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• 2021

In this work, we have performed a corrosion failure analysis of a leaking tube connected to an upper header of a condensate pre-heater in a heat recovery steam generator. It was revealed that the leakage position in the tube was the location where the materials were easily vulnerable due to tensile residual stresses induced by the material manufacturing process and welding process. In addition to an imbalance in the module induced by temperature difference during operation of the pre-heater, the weight of the modules and thermal fatigue provoked a type of stress of tensile-tensile fatigue on the tube. Thus, the leakage position of the pre-heater was exposed to the tensile stress on the inner surface of the tube facing the gas, which rendered the unstable oxide layer susceptible to corrosion and the formation of pits on the water side. The cracks propagated along with the degraded microstructure in a transgranular cracking mode under fatigue loading and finally resulted in water leakage.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.755-760
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• 2003

A novel current-fed energy-recovery sustaining driver (CFERSD) for a PDP is proposed in this paper. Its main idea is to recover the energy stored in the PDP or to inject the input source energy to the PDP by using the current source built-up in the energy recovery inductor. This method provides zero-voltage-switching (ZVS) of all main power switches, the reduction of EMI, and more improved operational voltage margins with the aid of the discharge current compensation. In addition, since the current flowing through the energy recovery inductor can compensate the plasma discharge current flowing through the conducting power switches, the current stress through all main power switches can be considerably reduced. Furthermore, it features a low conduction loss and fast transient time. Operations, features and design considerations are presented and verified experimentally on a 1020X106mm sized PDP, 50kHz-switching frequency, and sustaining voltage 140V based prototype.

• Journal of Power Electronics
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• v.6 no.3
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• pp.253-263
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• 2006

A high performance and low cost single switch current fed energy recovery circuit (ERC) for an alternating current (AC) plasma display panel (PDP) is proposed. Since it is composed of only one power switch compared with the conventional circuit consisting of four power switches and two large energy recovery capacitors, the ERC features a simpler structure and lower cost. Furthermore, since all power switches can be switched under soft switching operating conditions, the proposed circuit has desirable merits such as increased reliability and low switching loss. Specifically, there are no serious voltage notches across the PDP with the aid of gas discharge current compensation, which can greatly reduce the current stress of all inverter switches, and provide those switches with the turn on timing margin. To confirm the validity of proposed circuit, its operation and performance were verified on a prototype for 7-inch test PDP.

• Journal of Power System Engineering
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• v.15 no.5
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• pp.22-29
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• 2011

In this study, the damage mechanism of large scale steam turbine due to water induction was analyzed and recovery characteristics were reviewed. A turbine consists of the rotating rotor and the stationary casing, and the clearance between them is very small for the efficiency enhancement. If water induction, while relatively cold steam or water is introduced into turbine, occurs, the considerable humping is caused at the casing near the initial water induction point and that induces the rubbing between rotor and casing. Finally, it leads to the catastrophic failure. Bowed rotor has the different characteristics in the recovery depending on damage degree. The elastic deformation due to light rubbing is recovered by turning the rotor with 3 rpm under normal operation condition, but most plastic deformation due to rubbing deforms the local microstructure and that results in permanent deformation which could not be recovered under normal operation condition. Bowed rotor has diverse characteristics depending on the recovery method, and the method is empirical and needs the cutting edge technology. Careful recovery treatment of the rotor will eliminate the risks and secure the high quality rotor similar to new rotor. If any critical error is made during the recovery, the rotor would not be recovered permanently and it should be scrapped.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.12
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• pp.2056-2061
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• 2001

Non-proportional loading tests of Nylon 66 at room temperature exhibit path dependent behavior and plasticity-relaxation interactions. The uniaxial formulation of the viscoplasticity theory based on overstress (VBO), which has been used to reproduce the nonlinear strain rate sensitivity, relaxation, significant recovery and cyclic softening behaviors of Nylon 66, is extended to three-dimensions to predict the response in strain-controlled, comer-path tests. VBO consists of a flow law that is easily written for either the stress or the strain as the independent variable. The flow law depends on the overstress, the difference between the stress and the equilibrium stress that is a state variable in VBO. The evolution law of the equilibrium stress in turn contains two additional state variables, the kinematic stress and the isotropic stress. The simulations show that the constitutive model is competent at modeling the deformation behavior of Nylon 66 and other solid polymers.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1051-1056
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• 2007

The air suspension system is widely used in commercial vehicles such as buses or special purpose trucks because it improves ride better than any other types of suspension. Since the durability of vehicle parts is directly related to the safety, the evaluation of the durability at the design stage is necessary. In this research, the fatigue life of the air suspension frame for trucks is predicted by the modal stress recovery(MSR) method. Using the process proposed in this research, the fatigue life of vehicle parts can be predicted efficiently at the design stage.

• Journal of the Korean Graphic Arts Communication Society
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• v.21 no.1
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• pp.1-10
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• 2003

Printing ink is faced various shear stress situation until it transfer to the printed substrate through the press. And in each shear stress condition the ink is needed to keep the appropriate viscosity according to the condition. The change of printing ink viscosity has been explained by well-known through the viscosity profile curve. But actually, the quality of printed paper depends on the ink behavior after transfer the substrates. Like this, to look into the behaviour of the ink on the printed substrate, it is needed the experiment of the ink structure recovering by rheology study. In this study, by controling the $CaCO_3$ content in the ink, after investigating the effect of the ink's structure recovery of the pigment concentration, we intend to predict the printing quality of the ink behvior on the substrate depending on pigment content.