• Proceedings of the KSR Conference
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• 2010.06a
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• pp.498-506
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• 2010

The neutral section was installed in order to prevent conflict with different phase angle source in electric railway catenary system. The speed of electric train reduced due to coasting operation by notch off when it passed the neutral section. And, the catenary wire was damaged and the accident might be happened because of the arc generation when the electric train passed the neutral section with notch on condition. This project has a goal to develop the automatic changeover system using by noncontactless semiconductor device in neutral section of catenary system so that the train pass as notch-on condition. In this first year, we obtain as following results such as domestic and international systems applications and completion requirements, development and analysis of stability for automatic changeover system, design of static switching device on automatic changeover system in neutral section and drawing up interface design and specifications according to equipment.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.87-93
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• 1998

Pressure ripples of hydraulic vane pump results from flow ripples due to pump geometry and reverse flow through the discharge port due to compressibility of fluid and result in vibration and noise of connected hydraulic elements. In a balanced type vane pump, cam ring curve is important factor to influence the flow ripples. Therefore, to reduce the flow ripple, it has been required that optimal selection of seal region by proper design of cam ring and each port position, and notches for preventing the excessive reverse flow. This paper has been performed analytical study of compression characteristics with major design parameter in side plate and cam ring. and examined into the role of notch and radius reduction ratio.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.40-42
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• 2005

In this paper, thrust ripple is minimized using notch and slot-aperture width adjustment in a slotted PMLSM and then optimal design was achieved by using a neural network. This paper has used the moving model node technique to reduce the time and the effort for calculation according to changing design parameters. As the result, the detent force of optimal model is decreased from 9.44[N] to 0.97[N] greatly compare with it of basic model. The thrust is decreased 1.3[%] from 342.07[N] to 337.48[N] a little.

• Journal of electromagnetic engineering and science
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• v.10 no.1
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• pp.39-44
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• 2010

In this paper, a compact wideband antenna with a band-notch function is proposed. It operates over the UWB band with a band-stop characteristic. To increase the impedance bandwidth, a ring-shaped radiator is used. By attaching a circular stub to the ring-shaped radiator, the band-notch performance is obtained. The proposed antenna operates over a frequency range from 2.7 GHz to 11 GHz to satisfy the 10-dB return-loss requirement and provides band-stop performance in the frequency band from 5.15 GHz to 6.1 GHz. Experimental results reveal that the proposed antenna exhibits good radiation performance and is suitable for UWB applications.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.10a
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• pp.168-175
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• 1996

This paper reports on theoretical study of the pressure overshoot in the delivery ports and pressure rising within balanced type vane pump. Pressure overshoot occur due to the accelerated fluid through the notch, so, result in pressure ripple, flow ripple, and noise. For calculating the pressure rising and fluctuations of pressure, we have modeled mathematically used continuity equation based on compressibility and momentum equation considered fluid inertia in the notch, and analyzed simultaneously. As a results of analysis, we have found oscillation of pressure and compression chamber pressure depend on the rotational speeds, bulk modulus of working fluid, notches, number of vane and camring. Using the model, notches have been shown to be important design factor in relaxing the rapid pressure rising and reducing the amplitudes of pressure overshoot.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.5
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• pp.194-198
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• 2003

A wide-band E-plane notch phased array antenna having bandwidths of 3:1 and a scan volume of $\pm$ 45 is designed considering the active element pattern (AEP) with analysis of the full structure of E-plane notch phased array antenna. Using the numerical E-plane waveguide simulator as an infinite linear array in the broadside angle, the active reflection coefficient (ARC) of the unit element is optimized in the design frequency range. To evaluate the convergence of the AEP, the simulation of full array as changing the number array is investigated, and the minimum numbers of array that have characteristics similar to the AEP of an infinite array are determined.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.75-82
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• 2002

This paper presents a summary of the input data, requirements and notch prediction analysis for sinusoidal excitation test of a satellite. In the notch prediction analysis, the loads at excitation points and internal loads at the important locations on satellite structure were obtained. After checking of limit loads and margin of safety for each location, the notched sinusoidal test inputs were generated using the results of the notch prediction analysis.

• Structural Engineering and Mechanics
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• v.60 no.3
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• pp.387-404
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• 2016

In this paper, the response and failure of sharp-notched 6061-T6 aluminum alloy circular tubes with five different notch depths of 0.4, 0.8, 1.2, 1.6 and 2.0 mm subjected to cyclic bending were experimentally and theoretically investigated. The experimental moment-curvature relationship exhibits an almost steady loop from the beginning of the first cycle. And, the notch depth has almost no influence on its relationship. However, the ovalization-curvature relationship exhibits a symmetrical, increasing, and ratcheting behavior as the number of cycles increases. In addition, a higher notch depth of a tube leads to a more severe unsymmetrical trend of the ovalization-curvature relationship. Focusing on the aforementioned relationships, the finite element software ANSYS was used to continue the related theoretical simulation. Furthermore, the five groups of tubes tested have different notch depths, from which five unparallel straight lines can be observed from the relationship between the controlled curvature and the number of cycles required to produce failure in the log-log scale. Finally, a failure model was proposed to simulate the aforementioned relationship. Through comparison with the experimental data, the proposed model can properly simulate the experimental data.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.2 no.1
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• pp.22-29
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• 2003

A circuit model for the transition of stripline to dual slotline and a segmented method to analyze a notch antenna are presented. For the circuit model of the transition, the characteristic impedance, dispersions, and the shorted impedance of dual slotline are calculated and approximated with the closed-form expressions. The segmented analysis method allows to get readily an optimized results for the dual slotline-fed notch antenna. As a design example, a notch antenna is segmented into a 4'h order Marchand balun and a dual slot 134 notch antenna, and tested to show the validity of the proposed circuit model.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.2
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• pp.80-89
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• 1996

Fatigue life of a notched shaft was evaluated in order to estimate the durability and integrity of the notched shaft in design stage. Cumulative fatigue dama- ge analysis was performed using local strain approach based on the assumption that the fatigue life of a notched component is approximately same as that of a smooth specimen is subjected to the same strain at the notched component. In this paper, shafts with different notch root radius of 1, 2㎜ resulting in different values of stress concentration factors were tested under||rotating bending fatigue loading condition. Theoretical stress concentration factor for each notch type was calculated using finite element method. Fatigue life prediction program, FALIPS, written in C language was developed using the strain-life curve, and the local strain approach integrating Neuber's rule, cyclic stress-strain, and hysteresis loop equations. The fatigue life evaluated using the fatigue notch factor obtained from the experimentally determined fatigue strength showed very large scattering with nonconservatism, but the fatigue notch factors derived from the stress concentration factors and Peterson's equation reduced the considerablely accurate fatigue life evaluation within a factor of three.