• Proceedings of the KIPE Conference
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.713-716
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• 2000

In this paper a simple theory is presented to represent characteristic of a SRM and theoretical results are compared with experimental ones. In the theory the inductance variation of a SRM are approximated as linear and winding resistance and the magnetic saturation are ignored. With these approximations we derived some equations expressing load characteristics of a SRM Also the torque ripple was removed by applying a variable hysteresis band control.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제14권12호
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• pp.987-993
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• 2001

In this paper, we presents the construction details and output characteristics of a thick film piezoresistive strain gage. The thick film was printed on the ceramic diaphragm back side by screen printing and cured at 850$^{\circ}C$. The strain distribution and deflection on ceramic diaphragm were performed with finite-element method(FEM tool ANSYS-5.3). Various thick film strain gage characteristics were analysed, including nonlinearity, hysteresis, stability and sensitivity of thick film strain gages.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.225-231
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• 2000

Nonlinear characteristics of piezoelectric-type micro actuator used for hard disk drives are experimentally analyzed using Hutchinson's Magnum acturator. The nonlinear effects include hysteresis, superharmonic resonance, jump phenomenon, and shifting of natural frequencies. The effects of exciting frequency and input voltage on the nonlinear phenomena are investigated. It is shown that the micro actuator has the typical 3 times superhamonic resonances coupled to both 1st torsional and sway modes of the suspension.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제30권2호
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• pp.106-110
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• 2017

This paper compared current limiting characteristics of superconducting fault current limiter (SFCL) using E-I core due to the location of windings. Since E-I core has three legs and two magnetic paths, the current limiting characteristics of SFCL were expected to be affected by the installation location of windings, either center leg or right/left leg. To analyze its characteristics, the electrical equivalent circuit of the SFCL were derived and the electromagnetic analysis for the SFCL with the designed structure were performed. From the short-circuit tests, the hysteresis curve and the voltage-current trajectory of the SFCL due to the installation location of windings were extracted and compared each other. The SFCL with windings in the center leg of E-I core was shown to be larger magnetizing inductance compared to the one with windings in the right or left leg of E-I, which was analyzed from the hysteresis curve. In addition, larger decreased fault current right after the fault occurrence in the SFCL with windings in the center leg of E-I core was confirmed than the SFCL with windings in the right or left leg of E-I.

• Resources Recycling
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• 제13권6호
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• pp.37-42
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• 2004

The power loss analysis was carried out for Ni-Cu-Zn ferrite sample with different content of NiO and ZnO. The power loss, Pcv decreases monotonically with increasing temperature and attains to a certain value at around 100~120 degrees Celsius. The frequency dependence of Pcv can be explained by Pcv~f$^n$, and n is independent of the frequency, f up to 1 MHz. The Pcv decreases with an increase in ZnO/NiO. The Pcv was separated to hysteresis loss(Ph) and residual loss(Pcv-Ph). The temperature characteristics and compositional dependence of Pcv can be attributed to the Ph, while Pcv-Ph is not affected by both temperature and ZnO/NiO. By analyzing temperature and composition dependence of Ph and initial permeability, ${\mu}_i$ like following equations could be formularized. ${\mu}_i{\mu}_0=I_s^2/(K_I+b{\sigma}_0{\lambda}_s)$ Wh=13.5(I$_s^2/{\mu}_i{\mu}_0)$ Where ${\mu}_0$ is permeability of vacuum, I$_s$ is saturation magnetization, K$_I$ is anisotropy constant, $s_0$ is internal heterogeneous stress, ${\lambda}_s$ is magnetostriction constant, b is unknown constant, and Wh is hysteresis loss per one cycle of excitation (Ph=Wh${\times}$f). Steinmetz constant of Ni-Cu-Zn ferrite, m=1.64~2.2 is smaller than that of Mn-Zn ferrites, which suggests the difference of loss mechanisms between these materials.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 한국자원리싸이클링학회 2004년도 13회 산화철워크샵
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• pp.3-11
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• 2004

The power loss analysis was carried out for Ni-Cu-Zn ferrite samples with different content of NiO and ZnO. The power loss, Pcv decreases monotonically wi increasing temperature and attains to a certain value at around $100\~120$ degrees Celsius. The frequency dependence of Pcv can be explained by $Pcv\~f^n$', and n is independent of the frequency, f up to 1MHz. The Pcv decreases with an increase in ZnO/NiO. The Pcv was separated to hysteresis loss, Ph and residual loss, (Pcv-Ph). The temperature characteristics and compositional dependence of Pcv can be attributed to the Ph, while (Pcv-Ph) is not affected by both temperature and ZnO/NiO. By analyzing temperature and composition dependence of Ph and initial permeability, ${\mu}^i$ following equations could be formularized. $${\mu}_i{\mu}o=I_x\;^2/(K_1+bs_ol_s)\;\;\;\;(1)$$ $Wh=13.5(I_s\;^2/{\mu}_i{\mu}_o)\;\;\;\;(2)$$ Were ${\mu}_o$ is permeability of vacuum, $I_s$ saturation magnetization, $K_1$ anisotropy constant, $S_o$ internal heterogeneous stress, $I_s$, magnetostriction constant, b unknown constant. Wh hysteresis loss per one cycle of excitation (Ph: Wh*f). Steinmetz constant of Ni-Cu-Zn ferrites, $m=1.64\~2.2$ is smaller than the one of Mn-Zn ferrites, which suggests the difference of loss mechanism between these materials.

• Journal of the Earthquake Engineering Society of Korea
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• 제7권1호
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• pp.9-16
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• 2003

To evaluate the seismic performance of multistory building structures use an equivalent SDOF model to represent the resistance of the structure to deformation as it respond in its predominant mode. This paper presents a method of converting a MDOF system into an equivalent SDOF model. The principal objective of this investigation is to evaluate appropriateness of converting method through perform nonlinear time history analysis of a multistory building structures and an equivalent SDOF model. The hysteresis rules to be used an equivalent SDOF model is obtained from the pushover analysis. Comparing the peak inelastic response of a moment resisting reinforced concrete frames and an equivalent SDOF model, the adequacy and the validity of the converting method is verified. The conclusion of this study is following; A method of converting a MDOF system into an equivalent SDOF model through the nonlinear time history response analysis is valid. The representative lateral displacement of a moment resisting reinforced concrete frames is close to the height of the first modal participation vector \ulcorner$_1{\beta}$${_1{\mu}}=1$. It can be found that the hysteresis rule of an equivalent SDOF model have influence on the time history response. Therefore, it necessary for selecting hysteresis rules to consider hysteresis characteristics of a moment resisting reinforced concrete frames.

• Korean Chemical Engineering Research
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• 제60권2호
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• pp.208-216
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• 2022

Surface morphology and adsorption characteristics of black and white charcoals prepared from Korean traditional kiln were quantitatively analyzed. TGA and elemental analysis of charcoals were different from produced kiln, and thermal degradation temperature and carbon content of white charcoals were apparently higher than those of black charcoals. Surface morphology shows the activation progressed through the longitudinal direction of woods and new micropores were developed to radial direction on the surface of macropores as the furthermore activation resulting in the pore connection. BET adsorption isotherms show that there are low-pressure hysteresis due to the no desorption of adsorbates, which resulted in unique Type of charcoals overlapping Type I and Type IV. Such a low-pressure hysteresis is occurred from expansion of adsorbates, which were embedded in the micropore entrances and did not get out during the desorption run. The characteristics of charcoals such as specific surface area and pore size distribution did not show correct values depending on not only produced company but also sampling sites of one piece of charcoal. Therefore, it is not easy to suggest the quantitative characteristics of charcoals prepared from Korean traditional kiln. On the other hand, preparation the quality standard of charcoal is necessary for their special uses such as adsorbent.

• International Journal of Automotive Technology
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• 제8권4호
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• pp.455-465
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• 2007

The bushing element shows nonlinear characteristics in both displacements and frequencies, also with hysteretic responses for repeated vibrational excitations. Since the characteristics of the rubber bushing significantly affects the accuracy of the vehicle dynamic simulation result, it should be accurately modeled in the vehicle suspension model. To develop an accurate bushing model for vehicle dynamics analysis, the bushing characteristics under several excitation inputs must be known. In this paper, a 3-axis tester was used to capture the bushing characteristics. The random inputs, sine inputs, and step inputs were imposed on each axis of the bushing. Also, two-axis inputs, the radial-axial and radial-normal inputs, were simultaneously imposed on the tester. Three-axis inputs including the radial-axial-normal direction were supplied to the tester. Bushing characteristics of each case were precisely analyzed. These results could be available for dynamic modeling of bushing.

• Electrical & Electronic Materials
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• 제8권1호
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• pp.35-39
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• 1995

After making the light modulator using the BLN-PZT 9.0/65/35 specimen which has the slim-loop hysteresis characteristics and quadratic electro-optic characteristics, switching and spectral response characteristics were investigated. As the results of switching characteristics of the light modulator, it was found that the transmitted light intensity was modulated by both AC and pulse voltage. From the possibility of the selective transmission of the RGB(Red, Green, Blue) spectrum with electric field, the application for the light modulator, light shutter and color filter was expected.