• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.498-498
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• 2013

Atmospheric Pressure Plasmas have pioneered a new field of plasma for biomedical application bridging plasma physics and biology. Biological and medical applications of plasmas have attracted considerable attention due to promising applications in medicine such as electro-surgery, dentistry, skin care and sterilization of heat-sensitive medical instruments [1]. Traditional approaches using electronic devices have limits in heating, high voltage shock, and high current shock for patients. It is a great demand for plasma medical industrial acceptance that the plasma generation device should be compact, inexpensive, and safe for patients. Microwave-excited micro-plasma has the highest feasibility compared with other types of plasma sources since it has the advantages of low power, low voltage, safety from high-voltage shock, electromagnetic compatibility, and long lifetime due to the low energy of striking ions [2]. Recent experiment [2] shows three-log reduction within 180-s treatment of S. mutans with a low-power palm-size microwave power module for biomedical application. Experiments using microwave plasma are discussed. This low-power palm-size microwave power module board includes a power amplifier (PA) chip, a phase locked loop (PLL) chip, and an impedance matching network. As it has been a success, more compact-size module is needed for the portability of microwave devices and for the various medical applications of microwave plasma source. For the plasma generator, a 1.35-GHz coaxial transmission line resonator (CTLR) [3] is used. The way of reducing the size and enhancing the performances of the module is examined.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.396-399
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• 2002

Intense quasi-monochromatic x-ray irradiation from the linear plasma target is described. The plasma x-ray generator employs a high-voltage power supply, a low-impedance coaxial transmission line, a high-voltage condenser with a capacity of about 200 nF, a turbo-molecular pump, a thyristor pulse generator as a trigger device, and a flash x-ray tube. The high-voltage main condenser is charged up to 55 kV by the power supply, and the electric charges in the condenser are discharged to the tube after triggering the cathode electrode. The x-ray tube is of a demountable triode that is connected to the turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to the molybdenum target by the electric field in the tube, the weakly ionized plasma, which consists of metal ions and electrons, forms by the target evaporating. In the present work, the peak tube voltage was almost equal to the initial charging voltage of the main condenser, and the peak current was about 20 kA with a charging voltage of 55 kV. When the charging voltage was increased, the linear plasma x-ray source grew, and the characteristic x-ray intensities of K-series lines increased. The quite sharp lines such as hard x-ray lasers were clearly observed. The quasi-monochromatic radiography was performed by a new film-less computed radiography system.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.220-220
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• 2011

The Ne-Xe plasmas in dense plasma-focus device with coaxial electrodes were generated for extreme ultraviolet (EUV) lithography. The influence of gas mixture ratio, Ne-Xe (1, 10, 15, 20, 25, 30, 50%) mixture gas, on EUV emission measurement, EUV intensity and electron temperature in the coaxially focused plasma were investigated. An input voltage of 4.5 kV was applied to the capacitor bank of 1.53mF and the diode chamber was filled with Ne-Xe mixture gas at a prescribed pressure. The inner surface of the cylindrical cathode was lined by an acetal insulator. The anode was made of tin metal. The EUV emission signal of the wavelength in the range of 6~16 nm has been detected by a photo-detector (AXUV-100 Zr/C, IRD). The visible emission line was also detected by the composite-grating spectrometer of the working wavelength range of 200~1100 nm (HR 4000CG). The electron temperature is obtained by the optical emission spectroscopy (OES) and measured by the Boltzmann plot with the assumption of local thermodynamic equilibrium (LTE).

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.10
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• pp.435-442
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• 2006

One of the most important topics about the safety of electrical and electronic system is the reliability of the wiring system. The Time-Frequency Domain Reflectometry(TFDR) is a state-of-the-art system for detecting and estimating of the fault on a wiring. In this paper, We've considered the load resistance measurement on a coaxial cable using TFDR in a way of expanded application. The TFDR system was built using commercial Pci extensions for Instrumentation(PXI) and LabVIEW. The proposed real time TFDR system consisted of the reference signal design, signal generation, signal acquisition, algorithm execution and results display part. To implement real time system, all of the parts were programmed by the LabVIEW which is one of the graphical programming languages. Using the application software implemented by the LabVIEW, we were able to design a proper reference signal which is suitable for target cable and control not only the arbitrary waveform generator in the signal generation part but alto the digital storage oscilloscope in the signal acquisition part. By using the TFDR real time system with the terminal resistor on the target cable, we carried out load impedance measurement experiments. The experimental results showed that the proposed system are able not only to detect the location of impedance discontinuity on the cable but also to estimate the load resistance with high accuracy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.453-458
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• 2016

One of the most common applications of machine vision is quality inspections in automated production. In this study, a welding inspection system that is controlled by a PC and a PLC equipped with a multi-camera setup was developed. The system was designed to measure the primary dimensions, such as the length and width of the welding areas. The TCP/IP protocols and multi-threading techniques were used for parallel control of the optical components and physical distribution. A coaxial light was used to maintain uniform lighting conditions and enhance the image quality of the weld areas. The core image processing system was established through a combination of various algorithms from the OpenCV library. The proposed vision inspection system was fully validated for an actual weld production line and was shown to satisfy the functional and performance requirements.

• Composites Research
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• v.22 no.3
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• pp.44-54
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• 2009

In this paper, we proposed a numerical model the complex permittivity for the E-glass fabric/epoxy composite laminate containing electrical conductive carbon black. The model is based on the percolation theory and for the composites over than the percolation threshold and in higher frequency band in that the AC conductivity is fully proportional to the frequency. The measurement for the complex permittivity wasperformed at the frequency band of 0.5 GHz $\sim$ 18.0 GHz using a vector network analyzer with a 7 mm coaxial air line. The proposed model is composed of the numerical equations of the scaling law used in percolation theory and constants obtained from experiments to quantify the model itself. The model describes the complex permittivity as the function of frequency and filler concentration. The model was verified by being compared with the measurements.

• Composites Research
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• v.19 no.5
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• pp.28-33
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• 2006

In this paper, we have studied the complex permittivities and their influence on the design of microwave absorbers of E-glass fabric/epoxy composite laminates containing three different types of carbon-based nano conductive fillers such as carbon black (CB), carbon nano fiber (CNF) and multi-wall nano tube (MWNT). The measurements were performed fur permittivities at the frequency band of 0.5 GHz$\sim$18.0 GHz using a vector network analyzer with a 7 mm coaxial air line. The experimental results show that the complex permittivities of the composites depend strongly on the natures and concentrations of the conductive fillers. The real and imaginary parts of the complex permittivities of the composites were proportional to the filler concentrations. But, depending on the types of fillers and frequency band, the increasing rates of the real and imaginary parts with respect to the filler concentrations were all different. These different rates can have an effect on the thickness in designing the single layer microwave absorbers. The effect of the different rates at 10 GHz was examined by using Cole-Cole plot; the plot is composed of a single layer absorber solution line and measured permittivities from these three types of composites. Single layer absorbers of 3 different thicknesses using carbon nano materials were fabricated and the -10 dB band of absorbing performances were all about 3 GHz.

• Journal of the Korean Vacuum Society
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• v.15 no.6
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• pp.581-586
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• 2006

We have generated the argon plasma in the diode chamber based on the established coaxial electrode type and investigated the emitted visible light for emission spectroscopy. We applied various voltages $2\sim3.5kV$ to the device by 0.5kV, and obtained the emission spectrum data for the focused plasma in the diode chamber on the argon pressure of 330 mTorr. The Ar I and Ar II emission line are observed. The electron temperature and ion density have been measured by the Boltzmann plot and Saha equation from assumption of local thermodynamic equilibrium (LTE) The Ar I and Ar II ion densities have been calculated to be $\sim10^{15}/cc\;and\;~10^{13}/cc$, respectively, from Saha equation.