• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.194-197
• /
• 2003

The actively addressable carbon nanotube (CNT) emitters have been studied for stable and low-voltage driving field emission display (FED). The a-Si TFT and screen-printed CNT emitters were successfully integrated to fabricate the diode type active-matrix cathode and FED panel. Also, we propose a new FED architecture based on the actively controlled triode CNT emitters showing the properties of ideal triode type cathode with electron beam focusing effect.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.483-485
• /
• 2007

The active-matrix field emission display (AMFED) was fabricated by integrating carbon nanotube emitters on a-Si thin-film transistors. Also, the tapered macro-gate was adopted for high immunity to a high anode voltage and strong electron beam focusing. The fabricated AMFED was successfully driven with a low voltage of below 15 V.

• Journal of Digital Convergence
• /
• v.5 no.1
• /
• pp.77-89
• /
• 2007

The purpose of this exploratory study is to analyze the modelling behavior of public type quasi-government sector CEO, The results of this study on the 100 CEO is as followes: 1) Such behavior as pointed by government is more frequently practiced by CEO of the quasi-government sector. 2) The general level of modelling behavior by CEO doesn't meet the general expectations in spite of the many efforts of the CEO, Lastly, the summary and implications of this study is followed.

• Proceedings of the IEEK Conference
• /
• 2002.06a
• /
• pp.33-36
• /
• 2002

A new smart antenna scheme based on spatial FFT is proposed. By combining the output of spatial FFT, the proposed structure shows similar performance gain compared to ordinary smart antenna systems. Moreover. the proposed scheme could be easily integrated to general receiver without beam focusing module. The analysis and simulation results show that the performances of proposed scheme are comparable to ordinary smart antenna systems

• Proceedings of the Korean Magnestics Society Conference
• /
• 2014.11a
• /
• pp.98-99
• /
• 2014

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.36D no.9
• /
• pp.56-63
• /
• 1999

Conventional method to improve the response time of the Cat-SPPCM was to increase fanning beam using cylindrical lens. But, in this case the temporal instability of this SPPCM is increased, and fanning beam plays a role as noise, so that it decreases the reflectivity. Thus, fanning beam must be controlled to improve the properties of SPPCM. In this paper, we propose the method to increase the reflectivity of SPPCM and decrease the response time by focusing line-shaped input beam into photorefractive crystal using cylindrical lens and decrease the temporal instability of output beam by using mixed-polarized beam instead of simple extraordinary polarized beam. Optical experiments show that the reflectivity of proposed SPPCM is increased twice and the response time is reduced by 15 times. Also, we observed that the temporal instability of SPPCM is reduced when the polarization angle of the mixed-polarized beam is between $10^{\circ}$ and $30^{\circ}$ . We used a $45^{\circ}-cut\;BaTiO_3$ crystal which has high electro-optical coefficients in optical experiments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.5 s.108
• /
• pp.483-489
• /
• 2006

In this paper, new wideband lens amplifiers are proposed for C-band wireless communication service. In order to obtain the wideband property, all components of the proposed lens amplifiers are designed with balanced structure and wideband characteristics. Fat dipole antenna as the input and output antenna, balanced amplifier as amplifying components, and coplanar stripline(CPS) as the delay line fer the beam focusing are used fur composing the stable wideband lens amplifier. The $5{\times}5$ 2D lens amplifier has the characteristics that the absolute gain is 7.5 dB, the EIPG is 37.4 dB at 6 GHz, and the 3-dB gain bandwidth is 19.8 %.

• The Journal of the Acoustical Society of Korea
• /
• v.36 no.1
• /
• pp.23-29
• /
• 2017

A concept of a VSA (Virtual Source Array) is the method for an acoustic spatio-temporal focus at a selected location in the outbound direction with respect to the VSA without the need of a probe source as combines a TRP (Time-Reversal Processing) and time-delay and beam-steering. However, in TRP using the VSA concept, it is limited to the critical angle and the short distances relevant to the VSA. In this paper, the waveguide invariant theory is applied to the VSA concept to refocus the received field at ranges greater other than the critical angle and the short ranges by shifting the focused field. The suggested method is verified via numerical simulation, and the results show that the robust acoustic focusing is achieved on the selected location regardless of the limitation on the conventional VSA concept.

• Steel and Composite Structures
• /
• v.26 no.3
• /
• pp.329-345
• /
• 2018

This paper systematically investigated the mechanical performance of the weak-axis cover-plate connection, including a beam end monotonic loading test and a column top cyclic loading test, and a series of parametric studies for exterior and interior joints under cyclic loading using a nonlinear finite element analysis program ABAQUS, focusing on the influences of the shape of top cover-plate, the length and thickness of the cover-plate, the thickness of the skin plate, and the steel material grade. Results showed that the strains at both edges of the beam flange were greater than the middle's, thus it is necessary to take some technical methods to ensure the construction quality of the beam flange groove weld. The plastic rotation of the exterior joint can satisfy the requirement of FEMA-267 (1995) of 0.03 rad, while only one side connection of interior joint satisfied ANSI/AISC 341-10 under the column top cyclic loading. Changing the shape or the thickness or the length of the cover-plate did not significantly affect the mechanical behaviors of frame joints no matter in exterior joints or interior joints. The length and thickness of the cover-plate recommended by FEMA 267 (1995) is also suitable to the weak-axis cover-plate joint. The minimum skin plate thickness and a design procedure for the weak-axis cover-plate connections were proposed finally.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.18 no.5
• /
• pp.74-81
• /
• 2019

This study reports the CW $CO_2$ laser scribing of soda lime glass. In this study, scribing experiments are carried out at different laser powers, scan speeds, and focal positions to investigate the effect of the process parameters on the interaction characteristics between a laser beam and glass. In particular, the interaction characteristics are analyzed and described with the input laser energy per unit length. According to the experimental results, the damage threshold for the glass surface was found to exist between 0.072 and 0.08 J/mm. The input laser energy in this region induced partial melting of the surface and grain-shaped cracks. These cracks tended to increase as the input laser energy increased. At the laser input energy larger than 1 J/mm, a huge crack propagating along the scan direction was produced, and the volume below the scribed area was fully melted. The growth of this crack finally resulted in the complete cutting of the glass at the input laser energy above 8 J/mm. It was found that both the width and depth of the scribed line increased with increasing input laser energy. For the beam focusing at the rear surface, the width of the scribed line varied irregularly. This could be ascribed to the increased asymmetry of the beam intensity distribution when the laser beam was focused at the rear surface. Under this condition, a large burr was only produced on one side of the scribed line.