• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.1
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• pp.108-114
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• 1998

This paper presents the design and fabrication of waveguide E-plane metal insert bandpass filter for milli-meter waves which is analyzed transmission characteristics by calculating the generalized scattering matrix using mode-matching method. The bandpass filter was fabricated to verify the proposed method by the WR-34 rectangular waveguide to operate in 30.085 ~ 30.885 GHz. The fabricated waveguide E-plane metal insert band- pass filter was established the fact that it is so adaptive for milli-meter waves due to the measured data closely consistent with the results of analysis using mode-matching method, that is, the maximum value of insertion loss is 0.8 dB and the return loss is below -15 dB.

• Honam Mathematical Journal
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• v.30 no.1
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• pp.147-164
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• 2008

In the setting of the half-plane of the complex plane, we show that for r > $-{\frac{1}{2}}$, the dual space of the weighted Bergman spaces $B^{1,r}$ is the Bloch space and we introduce some operators. We also study Toeplitz and Hankel operators and we find some characterization of Hankel operators.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.9
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• pp.692-699
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• 1991

In this paper, graphical representations of parameter variations affected by series or parallel feedback in the load plane were studied. As a result of transformations, all parameters of 2-port was converted to circles, and the step of noise circles and gain circles was 0.1 dB and 1dB, respectively. Compared with conventional commercial CAD softwares, the circuit design procedures could be verified much more systemically. This CAD was programmed in C-language and executed in IBM-PC with VGA graphic adaptor.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.448-452
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• 2005

Punching/blanking/shearing is among the oldest and most frequently used sheet metal forming process. We have developed the shear device for burrless cutting using the micro wire. Since the burr minimization and fine shear plane, this paper is a study on the effect of the shear angle and clearance of the cutter-cutter. And, we confirm the tendency of the shear plane. It is impossible to completely remove the burr in the shearing process. In order to minimize the burr size and fine shear plane, we have accomplished the various experiment conditions such as the shear angle and clearance. Despite the quality of shear plane is not good enough yet, it is possible to make the burr minimization and fine shear plane by the optimization of process parameters.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.9
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• pp.171-182
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• 2019

Isogeometric concept is introduced to carry out free vibration analysis of plane structures. The geometry of structures is represented by using non-uniform rational B-spline surface (NURBS) and its basis function is consistently used in the formulation of plane stress element. In addition, multi-patch strategy is introduced to deal with the openings in building. The performance of the present isogeometric plane stress element is investigated by using five numerical examples. From numerical results, it is found to be that the isogeometric concept can successfully identify reliable natural frequencies and associated mode shapes of plane structures with/without openings in efficient way.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.5
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• pp.549-556
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• 2015

In this paper, design and fabrication for inset fed microstrip patch antennas applied to the $3{\times}3$ array CSLR and eight CSLR, respectively, to the ground plane are studied. The theoretical results are compared to the experimental results for the return loss and radiation pattern. For 'CSLR 09' antenna, the theoretical result for the resonant frequency and the return loss are 2.82 GHz and - 25.35 dB, respectively. The experimental results are obtained for a 2.885 GHz, -30.72 dB. Theoretical results for the resonant frequency and the return loss of the 'CSLR 08' antenna are 2.82 GHz, -16.77 dB, respectively, and the experimental results are obtained for a 2.885 GHz, -14.90 dB. In addition, E-plane and H-plane radiation patterns in comparison with designed and fabricated antennas are in good agreement.

• The korean journal of orthodontics
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• v.21 no.3
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• pp.673-683
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• 1991

This research was performed to find out the adaptation patterns of maxillary and mandibular posterior teeth to the changes in relationships of vertical skeletal components, which constitute the skeletofacial complex. For this research, 61 adult malocclusion patients were chosen as subjects according to the Hellman's dental age with normally ranged FMN-A-B angle. These subjects were divided into 4 groups in maxilla and 3 groups in mandible according to mesiodistal inclinations of teeth. Following results were obtained after studying the relationships of the vertical skeletal components between each group. 1. Inspire of the fact that the FMN-A-B angle was within a normal range, the degree of mesiodistal inclinations of maxillary and mandibular posterior teeth showed differences in relation to the anteroposterior relationships of maxilla and mandible. In case where the FMN-A-B angle was large, the mesial inclinations of maxillary posterior teeth showed more increase from the posterior to the anterior, whereas in mandible it showed overall decrease. 2. The degrees of mesial inclinations of mandibular posterior teeth were increased when the angulations of lower facial height, occlusal plane angle and mandibular plane angle were greater. 3. The patterns of mesial inclinations of maxillary posterior teeth were varied according to the angulation of lower facial height. If relatively large, it showed more increase from the posterior to the anterior and it was decreased nearly consistent when the angulation was small. 4. The degrees of mesial inclinations of maxillary posterior teeth were decreased as the lower facial height, palatal plane angle, occlusal plane angle and the mandibular plane angle became greater.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.11
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• pp.3598-3606
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• 1996

The finite volume method for radiation is applied to investigate a radiative heating of rocket base plane due to searchlight and plume emissions. Exhaust plume is assumed to absorb, emit and scatter the radiant energy isotropically as well as anisotropically, while the medium between plume boundary and base plane is cold and nonparticipating. Scattering phase function is modelled by a finite series of Legendre polynomials. After validating benchmark solution by comparison with that of previous works obtained by the Monte-Carlo method, further investigations have been done by changing such various parameters as plume cone angle, scattering albedo, scattering phase function, optical radius and nozzle exit temperature. The results show that the base plane is predominantly heated by the plume emission rather than the searchlight emission when the nozzle exit temperature is the same as that of plume.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.6
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• pp.792-801
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• 2000

The problem of phase change from liquid to solid in the inviscid plane-stagnation flow is theoretically investigated. The solution at the initial stage of freezing is obtained by expanding it in powers of time, and the final equilibrium state is determined from the steady-state governing equations. The transient solution is dependent on the three dimensionless parameters, but the equilibrium state is determined by one parameter of (temperature ratio/conductivity ratio). The effect of the fluid flow on the growth rate of the solid in the pure conduction problem can be clearly seen from the solution of the initial stage and the final equilibrium state. The characteristics of the transient heat transfer at the surface of the solid and the liquid side of the solid-liquid interface for all the dimensionless parameters are elucidated.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.912-918
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• 2009

In this paper, we carried out a comparative analysis of partial discharge(PD) patterns caused by deterioration of cast-resin and oil insulation systems. Various electrode systems were fabricated such as needle-needle, needle-plane and plane-plane to simulate defects that may exist in the insulation system of transformers. A low-noise amplifier which has a gain of 40 dB and a frequency bandwidth of 500 kHz $\sim$ 30 MHz (-3 dB) was designed to detect small PD signals. From the analysis of acquired PD signals, we could find that a unique PD pattern is formed according to types of defect. These data will be applied usefully to diagnose insulation condition of transformers.