• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.220-222
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• 2005

The Cold cathode fluorescent lamp(CCFL) are used to illuminate the liquid crystal display(LCD). Ballasts are required for CCFL because the lamp need high starting voltage and behave negative dynamic resistant characteristics in the desired region of operation. In this paper, the lamp impedance model is proposed, and this model is established from some equations and measured electrical characteristics of CCFL. The validity of porposed lamp model is verified from the simulation and experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.244-249
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• 1997

The enclosure with a small opened area is extensively used in power plants to reduce the propagating noise from transformers. The radiation impedance associated with the location and width of the opened area, and the geometric configurations of internal acoustic field is very important to determine the basic acoustic characteristics of this partial enclosure. In this study, two-dimensional rectangular chambers with opened areas are investigated to examine the acoustic properties of the enclosure. The mode expansions of the physical variables defined on boundary surfaces are introduced to derive a simple algebraic equation. The acoustic characteristics can be easily predicted by this analytical approach, and the results well agree with physical grounds. Physical concepts as results of this work will be helpful to use the partial enclosure as a noise control element.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.1
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• pp.1-5
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• 1998

This study presents intelligent deburring system which can transfer the exper's skill to deburring robot through neural network. The expert's skill is expressed as associate mapping between the characteristics of the burr and human expert's action. Under the fundamental idea that the state of the deburring process can be extracted via the visual sense of the human, we employ vision system for the perception and identification of the changing burr. From the demonstration of human experts, force data are measured and fitted impedance model. Finally the characteristics of the burr and coressponding force are associated by the neural network which is trained through many demonstrations. The proposed method is verified in the deburring process of welding burr.

• Proceedings of the KIEE Conference
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• summer
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• pp.394-396
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• 2004

In order to reduce the sheath circulating current, same arrangement and balanced length of cable are required for the underground cable system. But practically, changing the whole arrange of cable which is already constructed is impossible. Therefore, It is necessary to apply the restraining-unit of sheath circulating current at the cross-bonding wire of insulated joint because the impedance of restraining-unit is able to reduce sheath circulating current at a normal condition. Even at a transient state, the restraining-unit must maintain electrical and mechanical characteristics. In this paper, the features of restraining-unit developed by LG Cable as well as the electrical test results are described. It proves that the restraining-unit is applicable to the underground cable system where sheath circulating current rises.

• Korean Journal of Metals and Materials
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• v.49 no.11
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• pp.839-844
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• 2011

We examined the effects of alloying elements such as Fe, Ga, In, Sn, Mg, and Mn on the electrochemical characteristics of Al-based alloys for Al-air batteries by potentiodynamic polarization tests and electrochemical impedance spectroscopy. The corrosion potential of an Al anode was lowered by the addition of Ga and Sn, resulting in an increase in the cell voltage compared with a pure Al electrode. Fe was not beneficial to improve the electrochemical properties of the Al anode in that it caused a decrease in the cell voltage and reduced corrosion rate slightly. In, Mn, Sn, and Mg decreased the corrosion rate of the Al alloys, while Ga enhanced corrosion significantly and accelerated consumption of the anode.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.6
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• pp.853-856
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• 2021

In this paper, a low noise amplifier having high gain and low noise by using input and inter stage matching circuits has been designed. A current-reused two-stage common-source topology is adopted, which can obtain high gain and low power consumption. Deterioration of noise characteristics according to the source inductive degeneration matching is compensated by adopting additional matching circuits. Moreover trade-offs among noise, gain, linearity, impedance matching, and power dissipation have been considered. In this design, 0.18-mm CMOS process is employed for the simulation. The simulated results show that the designed low noise amplifier can provide high power gain and low noise characteristics.

• Journal of information and communication convergence engineering
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• v.22 no.3
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• pp.173-180
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• 2024

This study proposed an interdigital band-pass filter based on the microstrip transmission line. When designing a conventional structure for an interdigital filter based on the characteristics of the 5th order transmission line, seven resonators are required. By changing the impedance of the resonator adjacent to the feed line, the proposed interdigital band-pass filter was designed to reduce the number of resonators compared to conventional interdigital band-pass filters. Consequently, the resonator order decreased, and return and insertion losses become comparable to that in case of a conventional interdigital filter design. The proposed band-pass filter was designed with a center frequency of 2.75 GHz and a bandwidth of 1.5 GHz. Furthermore, based on various transmission characteristics such as group delay and coupling coefficient, two band-pass filters were designed, compared, and analyzed.

• Journal of Sasang Constitutional Medicine
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• v.21 no.3
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• pp.48-62
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• 2009

1. Objectives: The purpose of this study was to analyze the physical and psychological characteristics of each Sasang type groups which were classified by Sasang medicine specialist. 2. Methods: The subjects were 115 (85.2% of male) university students with $26.8\pm5.4$ yrs. of age and $12.9\pm1.7$ yrs. of education. We can get 30 of Soyang type, 39 of Taeeum type, 46 of Soeum type after the Sasang type classification. Their physical characteristics were measured with Bioelectrical Impedance Analysis (Inbody 720, Biospace, Seoul), and psychological characteristics with Temperament and Character Inventory (Maumsarang, Seoul). The general linear model (SPSS 12.0, SPSS Inc, Chicago) were used for the analysis with gender and age as covariance. 3. Results and Conclusions: Taeeum type group ($75.64\pm13.01$, $26.12\pm4.16$, $15.74\pm2.42$, $11.30\pm1.80$, $3.93\pm0.62$, $18.43\pm7.70$) showed significantly bigger weight, intra-cellular water, extra-cellular water, protein, mineral, body fat mass than Soeum type group ($61.32\pm8.56$, $22.54\pm3.87$, $13.70\pm2.15$, $9.74\pm1.68$, $3.35\pm0.51$, $10.79\pm3.97$). In obesity degree such as Body Mass Index and Waist-hip ratio, and circumference measures in chest, waist and hip, we found significant differences in the order of Taeeum>Soyang>Soeum. As a psychological perspectives Soyang type group ($41.90\pm13.32$) has higher NS (Novelty-Seeking) score than Soeum type group ($35.22\pm11.22$) with marginal significance (p=0.052). In sub-scale measurements Soeum type group ($10.61\pm3.69$) has significantly lower value than other two groups in P3 (Ambition). The results of present study showed that Taeeum type by specialist has same physical characteristics as previously reported QSCC II based studies. Temperament profile of each Sasang type group will serve as an important evidence for further study showing that the Sasang typology has biological basis.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.734-741
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• 1998

Electrode characteristics were studied in the interface between sample solutions and $K^+$ ion selective PVC membrane electrodes containing neutral carriers, dibenzo-18-crown-6(D18Cr6) and valinomycin(Val). The effect of doping of base electrolytes, the chemical structure and the content of carrier, variation of plasticizer, membrane thickness, and concentration variation of sample solution on the response characteristics of electrode such as the measured Nernstian slope, the detection limit, the linear response range, and potentiometric selectivity coefficients, were studied. In order to synthesize the membrane D18Cr6 and Val as neutral carriers were used, and complex between the carrier and $K^+$ ions were used as active materials. PVC membrane electrodes were made of plasticizers (DBP, DOS, and DBS), the base electrolyte[potassium tetraphenylborate(KTPB)], and solvent(THF). The chemical structure of carrier D18Cr6 was best for electrode and ideal electrode characteristics were appeared especially in case of doping of TPB. The optimum carrier content was about 3.23 wt % in case of D18Cr6 and Val. DBP was best as a plasticizer. As membrane thickness decreased the electrode characteristics was improved. But its characteristics were lowered below the optimum membrane thickness because of the elution of carrier, deterioration of membrane strength, etc. In the case of D18Cr6, the selectivity coefficients by the mixed solution method for the $K^+$ ion were in the order of $NH_4{^+}>Ca^{2+}>Mg^{2+}>Na^+$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.130-133
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• 2000

The optical characteristics of merocyanine dyes have been investigated widely due to their possible application to the high efficiency photo-electric devices. The optical systems are mostly fabricated using vacuum evaporation. casting and Langmuir-Blodgett method and the arrangement and orientation of dye molecules is one of the most important factors in the study on the optical characteristics. In this study. we fabricated the molecular systems through the LB techniques and investigated the optical characteristics of merocyanine dye LB film using the oscillation characteristics of quartz crystal. It was quite interesting behavior that the resistance and frequency shift at the parallel resonance under the UV irradiation.