• 전자공학회논문지 IE
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• v.44 no.2
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• pp.21-25
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• 2007

Multilayer transparent electromagnetic wave shielding film with 1 m wide, was fabricated by using roll to roll DC plasma coating with ITO and Ag layer on PET substrate. By optimizing properly the design parameters, such as a processing condition, the surface resistance and the thickness of each layers, the homogeneous film could be obtained. Electromagnetic wave shielding film showed the high shielding effectiveness of 23dB(99.5%) in 2-18 GHz range and the transmittance of 83.1% in 400-700nm.

• Korean Journal of Animal Reproduction
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• v.19 no.3
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• pp.171-179
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• 1995

This study was carried out to investigate the fertilizing ability of round spematids isolated from seminiferous tubules. A round spermatid was introduced into the perivitelline space of a mature oocyte using Leitz micromanipulators and then subjected to electrofusion. Electrofusion was induced by applying a single DC pulse of 90V with a duration of 60$\mu$sec using Model 611 Square Wave Stimulator(Phipps and Bird, U.S.A) in 0.3 M sucrose fusion medium containing 0.05mM CaCl2 and 0.1mM MgSO4, Oocyte pre-activation was conducted by exposure to a single DC(80V, 80$\mu$sec) pulse in electrofusion medium at 1 hour before electrofusion. The incidence of fusion with pre-activated oocytes(23.8%, 57/239) was higher than that with nonactivated oocytes(6.7%, 3/45). The most of electro-stimulated mouse oocytes cleaved regardless of the success or failure of fusion. Karyotyping of embryos that developed into blastocysts after exposure to the fusion pulse were performe. We found that blastocysts from the fused oocytes were diploid whereas blastocysts from the unfused oocytes were haploid. About 11.7 and 11.5% of fused and unfused oocytes were developmental potentials of fused and unfused oocytes. Therefore, these results suggest that the mouse mture oocyte can be fertilized by fusion with a round spermtid and subsequently developed normally.

• Journal of Welding and Joining
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• v.23 no.1
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• pp.69-76
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• 2005

Recently, application of arc welding to galvanized carbon steel sheet is on the increasing Ould in the fields of automobile and construction industries. In arc welding process, zinc is evaporated in weld pool, even under the appropriate welding condition and produce blowhole and/or pit. Zinc gas cause instability of arc and increase spatter and fume. This research is purposed to minimize the heat-input and the formation of porosities in the welded joint of the galvanized carbon steel sheet using variable polarity AC wave pulse MIG welding system. An appropriate welding condition which showed low spatter and good bead appearance was acquired by applying the AC pulse MIG welding machine to DC duplicated MIG welding with the solid wire. When oxygen gas was added to shield gas of MIG welding for galvanized steel sheet, arc length was increased and arc stability was improved. In the AC duplicated welding, the loss of galvanized layer was decreased as the amount of heat-input was decreased when the EN ratio was increased under the condition that average welding current was evenly set.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.846-856
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• 1998

In this paper, we have applied Berenger's perfectly matched layer(PML) absorbing boundary conditition(ABC) with three dimension at the propagation direction of field, side boundary and upper boundary in which evanescent and radiation field is exist. Even though the same computationaal domain is used, PML is superior to other ABC in the absorbing ability that is obtained reflective coefficient about $10^{-4}$ unit for the propagation wave, but PML is ineffective in absorbing evanescent field. Also we have compared dispersive characteristics of the microstrip with Kobayashi's emprical method, and obtaind very similar result, but 0.8% error is generated at the dc or near.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.1
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• pp.23-32
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• 2011

In this paper, we develop a method for generating thumbnail images at hybrid domain combined the spatial domain and transform domain. The proposed method generates a pixel of a thumbnail image by adding a DC value of residual transform coefficients and an average value of an estimate block. For effectively calculating average values of estimate blocks, we propose a method for reconstructing the boundary pixels of a block. In comparison to the conventional method of decoding the bit stream then scaling down the decoded images, the developed method reduces the complexity by more than 60% while producing identical thumbnail images.

• Journal of Power Electronics
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• v.15 no.2
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• pp.346-355
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• 2015

On the basis of the conventional PID control algorithm, a modified adaptive PID (MA-PID) control algorithm is presented to improve the steady-state and dynamic performance of closed-loop systems. The proposed method has a straightforward structure without excessively increasing the complexity and cost. It can adaptively adjust the values of the control parameters ($K_p$, $K_i$ and $K_d$) by following a new control law. Simulation results show that the line transient response of the MA-PID is better than that of the adaptive digital PID because the differential coefficient $K_d$ is introduced to changes. In addition, experimental results based on a FPGA indicate that the MA-PID control algorithm reduces the recovery time by 62.5% in response to a 1V line transient, 50% in response to a 500mA load transient, and 23.6% in response to a steady-state deviation, when compared with the conventional PID control algorithm.

• Journal of Institute of Convergence Technology
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• v.6 no.1
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• pp.23-26
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• 2016

DC motor shafts have several defects such as double cut, deep scratch on surface, and defects in diameter and length. The deep scratches are due to collision among the other shafts. So the scratches are long and thin but their orientations are random. If the smallest enclosing box, i.e. oriented bounding box for a detective point group is found, then the size of the corresponding defect can be modeled as its diagonal length. This paper proposes an suface inspection algorithm for the DC motor shaft using the oriented bounding box. To evaluate the proposed algorithm, a test bed is made with a line scan CCD camera (4096 pixels/line) and two rollers mechanism to rotate the shaft. The experimental result on a pre-processed image with contrast streching algorithm, shows that the proposed algorithm sucessfully finds 150 surface defects and its computation time (0.291 msec) is enough fast for the requirement (4 seconds).

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.12-23
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• 2021

This paper proposes a low power radio frequency receiver front-end where, in a single stage, single-balanced mixer and voltage-controlled oscillator are stacked on top of low noise amplifier and re-use the dc current to reduce the power consumption. In the proposed topology, the voltage-controlled oscillator itself plays the dual role of oscillator and mixer by exploiting a series inductor-capacitor network. Using a 65 nm complementary metal oxide semiconductor technology, the proposed radio frequency front-end is designed and simulated. Oscillating at around 2.4 GHz frequency band, the voltage-controlled oscillator of the proposed radio frequency front-end achieves the phase noise of -72 dBc/Hz, -93 dBc/Hz, and -113 dBc/Hz at 10KHz, 100KHz, and 1 MHz offset frequency, respectively. The simulated voltage conversion gain is about 25 dB. The double-side band noise figure is -14.2 dB, -8.8 dB, and -7.3 dB at 100 KHz, 1 MHz and 10 MHz offset. The radio frequency front-end consumes only 96 ㎼ dc power from a 1-V supply.

• Korean Journal of Materials Research
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• v.31 no.11
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• pp.635-641
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• 2021

Cr thin films with O added are deposited on sapphire substrate by DC sputtering and are nitrided in NH₃ atmosphere between 300 and 900 ℃ for various times. X-ray diffraction results show that nitridation begins at 500 ℃, forming CrN and Cr₂N. Cr oxides of Cr₂O₃ are formed at 600 ℃. And, at temperatures higher than 900 ℃, the intermediate materials of Cr₂N and Cr₂O₃ disappear and CrN is dominant. The atomic concentration ratios of Cr and O are 77% and 23%, respectively, over the entire thickness of as-deposited Cr thin film. In the sample nitrided at 600 ℃, a CrN layer in which O is substituted with N is formed from the surface to 90 nm, and the concentrations of Cr and N in the layer are 60% and 40%, respectively. For this reason, CrN and Cr₂N are distributed in the CrN region, where O is substituted with N by nitridation, and Cr oxynitrides are formed in the region below this. The nitridation process is controlled by inter-diffusion of O and N and the parabolic growth law, with activation energy of 0.69 eV.

• Journal of the Korean Ceramic Society
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• v.43 no.2 s.285
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• pp.79-84
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• 2006

We studied the microstructure and magnetic property of the pulsed DC magnetron sputtered $Zn_{\0.8}Co_{0.2}O$ film as a function of substrate temperatures. The X-ray patterns of the $Zn_{\0.8}Co_{0.2}O$ film showed a strong (002) preferential orientation at $500^{\circ}C$. The films with a crystallite size of 23-35 nm were grown in the form of nano-sized structure and this tendency was remarkable with increasing substrate temperature. The UV-visible result showed that the $Zn_{\0.8}Co_{0.2}O$ film prepared above $300^{\circ}C$ has a high optical transmittance of over $80\%$ in the visible region. The absorption bands were observed due to sp-d interchange action by $Co^{2+}$ complex ion and dd transition in the region from 500 to 700nm. The resistivity of the film was below $10^{-1}\;\Omega-cm\;above\;300^{\circ}C$. The AGM analysis results for the all films showed the magnetic hysteresis curves of ferromagnetic nature. The low electrical resistivity and room temperature ferromagnetism of ZnCoO thin films 'deposited above $300^{\circ}C$ suggested the possibility for the application to Diluted Magnetic Semiconductors (DMSs).