• Journal of electromagnetic engineering and science
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• v.17 no.1
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• pp.14-19
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• 2017

In this paper, a planar directional beam-switchable antenna with four orthogonal beam directions is proposed. The proposed antenna is designed with two crossed active elements and two parasitic elements for each direction. The design methodology is described on the basis of the Yagi-Uda method for the active and parasitic elements, respectively. By adjusting the effective electric lengths of the parasitic elements, the roles of a director and a reflector are exchanged with each other. The planar four-way beam-switchable Yagi-Uda antenna is implemented. From the experimental results. The proposed design method is verified for orthogonal radiation beam switching.

• Journal of KSNVE
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• v.8 no.4
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• pp.663-669
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• 1998

In this paper, a beam design method is presented for the planar array with unequal transducer sensitivities. Basically the proposed method consists of two steps. At first, the optimum weightings are designed with the assumption that all array elements have an uniform sensitivity. Next, the compesnated weightings for the unequal transducer sensitivities can reversely be determined from an inverse problem utilizing the design beam pattern evaluated by the predetermined optimal weightings. A numerical example is inculded to illustrate the proposed method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.7
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• pp.35-40
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• 2020

This work is concerned with various planar deformations of an isotropic sandwich beam, which generally consists of three layers: two stiff skin layers and one soft core layer. When one layer of the sandwich beam is modeled as a beam, the variational-asymptotic method is rigorously used to construct a zeroth-order beam model, which is similar to a generalized Timoshenko beam model capable of capturing the transverse shear deformations but still carries out the zeroth-order approximation. To analyze the planar sandwich beam, the sum of the energies of the two skin layers and one core layer is then formulated with different material and geometric properties and represented by a universal beam model in terms of the core-layer kinematics through interface displacement and stress continuity conditions. As a preliminary validation, two extreme examples are presented to demonstrate the capability and accuracy of this present approach.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.703-708
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• 2006

The cantilever beam with nonlinearity has many dynamic characteristics of nonlinear vibration. Nonlinear terms of a flexible cantilever beam include inertia, spring, damping, and warping. When the beam is given basic harmonic excitation, it shows planar and nonplanar vibrations due to one-to-one resonance. And when the one-to-one resonance occurs, the flexible beam shows different behaviors in those vibrations. For the one-to-one resonance occurring in each mode, the phase value of the planar vibration is different from that of the nonlinear vibration. This paper investigates the phase change and the phase difference between such planar and nonplanar vibrations which are caused by one-to-one resonance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.1 s.118
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• pp.48-54
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• 2007

The cantilever beam with nonlinearity has many dynamic characteristics of nonlinear vibration. Nonlinear terms of a flexible cantilever beam include inertia, spring, damping, and warping. When the beam is given basic harmonic excitation, it shows planar and nonplanar vibrations due to one-to-one resonance. And when the one-to-one resonance occurs, the flexible beam shows different behaviors in those vibrations. For the one-to-one resonance occurring in each mode, the phase value of the planar vibration is different from that of the nonlinear vibration. This paper investigates the phase change and the phase difference between such planar and nonplanar vibrations which are caused by one-to-one resonance.

• Steel and Composite Structures
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• v.39 no.3
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• pp.337-352
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• 2021

The study presented experimental and numerical investigation on the seismic performance of steel reinforced concrete (SRC) L-shaped column- reinforced concrete (RC) beam joints. Various parameters described as steel configuration form, axial compressive ratio, loading angle, and the existence of slab were examined through 4 planar joints and 7 spatial joints. The characteristics of the load-displacement response included the bearing capacity, ductility, story drift ratio, energy-dissipating capacity, and stiffness degradation were analyzed. The results showed that shear failure and flexural failure in the beam tip were observed for planar joints and spatial joint, respectively. And RC joint with slab failed with the plastic hinge in the slab and bottom of the beam. The results indicated that hysteretic curves of spatial joints with solid-web steel were plumper than those with hollow-web specimens. The capacity of planar joints was higher than that of space joints, while the opposite was true for energy-dissipation capacity and ductility. The high compression ratio contributed to the increase in capacity and initial stiffness of the joint. The elastic and elastic-plastic story deformation capacity of L-shaped column frame joints satisfied the code requirement. A design formula of joint shear resistance based on the superposition theory and equilibrium plasticity truss model was proposed for engineering application.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.62-65
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• 2006

In this paper, nonlinear nonplanar vibration of a flexible rectangular cantilever beam is analyzed when one-to-one resonance occurs to the beam. The planar and nonplanar motions of the beam are analyzed in time and frequency domains. In frequency domain, FFT analyzer is used to perform autospectrum and cepstrum analyses for nonlinear response of the beam. In time domain, an oscilloscope is used to investigate the phase difference between the planar and nonplanar motions and to perform Torus analysis in the phase space. Through those analyzing process, the main frequencies of superharmonic, subharmonic, and super-subharmonic motions are investigated in the nonplanar motion due to one-to-one resonance. Analyzing the phase difference between the planar and nonplanar motions, it is observed that the phase difference varies in time.

• Korean Journal of Materials Research
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• v.12 no.3
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• pp.195-199
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• 2002

Planar Hall effect of ferromagnetic GaMnAs thin films was investigated for the first time. The films were grown in an optimized growth condition via molecular beam epitaxy at low temperatures. For the optimization of the growth conditions, we used reflection high-energy electron diffraction, electrical conductivity, double crystal x-ray diffraction, and superconducting quantum interference device measurements techniques. We observed that the difference between the longitudinal resistance and the transverse resistance matches the planar Hall resistance. The ratio of the planar Hall resistance at saturation magnetic field to that at zero reached above 500%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.879-880
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• 2009

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1791-1793
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• 1998

The thin film metal electrode for PDP needs low resistivity and strong adhesion. But the sputtered copper film is weak, in the adhesion between copper and glass. In this paper, we investigated the characteristics of resistivity and adhesion about Cu thin film using Ion Beam Assisted DC Planar Magnetron Sputtering(DCPM) Device.