• Journal of Power Electronics
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• v.11 no.4
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• pp.612-619
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• 2011

This paper presents a water treatment system for leachate from sewage-filled ground that uses a pulsed-power modulator developed based on semiconductor switches in order to realize a long life, a high repetition rate, and a fast rising time. The specifications of the developed pulsed-power modulator are the pulsed output voltage, the output current, the pulse repetition rate (PRR), the pulse width, and an average output power of $60\;kV_{max}$, $300\;A_{max}$, 3000, $50\;{\mu}s$, and 15 kW, respectively. The pulsed-power water treatment system was introduced and analyzed using an equivalent electrical circuit model to optimize the output voltage waveform. The experimental results verify that the proposed water treatment system can be effectively used for industrial applications.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1850-1852
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• 2002

In this paper, we studies EMTP analysis and characteristics of critical voltage of pulse corona and load impedance on variable electrode length. To obtain a stable Pulse voltage, we designed a compact pulse generator switched MOSFET and tested their characteristics by adjusting electrode length and pulse repetition. As a result, critical voltage of pulse corona and load impedance on increasing electrode length were decreased. These results indicate we can control critical voltage of pulse corona and suppress arc discharging between two electrodes.

• Journal of Fashion Business
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• v.16 no.4
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• pp.100-106
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• 2012

This research was carried out to find the mordant effect of Chestnut's inner skin on the cow leather dyed by Turmeric powder. The best proper mordanting conditions were examined by changing mordant method, concentration, temperature, bath ratio, time, and repetition. Also dyeability and surface color changes were evaluated by various mordanting methods. The optimum mordanting conditions of chestnut's inner skin extract on the cow leather were pre mordant, 80%, $50^{\circ}C$, 50:1, 40minutes, 4 repetition. The K/S values as a mordant were higher in pre mordant than post mordanting condition. Although the ${\Delta}E$ was slightly higher in post mordant than pre mordant, it was too small to find any means. The surface colors of all dyed cow leathers were yellow. Among light, dry cleaning, and abrasion fastnesses, only light fastness was increased one degree, others were same degrees.

• Textile Coloration and Finishing
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• v.13 no.2
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• pp.7-7
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• 2001

This paper investigated the dyeability and surface color of silk and cotton fabrics dyed with chustnut bur extract. Some experiments were performed under the various dyeing conditions such as dyeing temperature, dyeing time, repetition of dyeing, dyeing pH, mordanting condition, washing fastness and light fastness with silk and cotton fabrics. The results obtained were as follows 1. △E value was increased when dyeing temperature and time was higher, value of munsell was shifted from Yellow to Yellow-Red at hither dyeing temperature and time in silk and cotton fabrics. 2. Optimal dyeing pH was increased with acidity of dyeing solution in silk and cotton fabrics, and repetition of dyeing did not change the dye-uptake. 3. When mordanting time and temperature was higher, △E value was larger in silk and cotton fabrics. Silk and cotton fabrics with Fe-premordanting treatment had best dyeability, but treatment with Sn-mordanting was worst. 4. Washing fastness and light fastness was excellent in various dyeing condition at silk fabric but cotton was without practical use.

• Textile Coloration and Finishing
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• v.13 no.2
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• pp.93-103
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• 2001

This paper investigated the dyeability and surface color of silk and cotton fabrics deed with chustnut bur extract. Some experiments were performed under the various dyeing conditions such as dyeing temperature, dyeing time, repetition of dyeing, dyeing pH, mordanting condition, washing fastness and light fastness with silk and cotton fabrics. The results obtained were as follows 1. $\Delta{E}$ value was increased when dyeing temperature and time was higher, value of munsell was shifted from Yellow to Yellow-Red at hither dyeing temperature and time In silk and cotton fabrics. 2. Optimal dyeing pH was increased with acidity of dyeing solution in silk and cotton fabrics, and repetition of dyeing did not change the dye-uptake. 3. When mordanting time and temperature was higher, $\Delta{E}$ value was larger in silk and cotton fabrics. Silk and cotton fabrics with Fe-premordanting treatment had best dyeability, but treatment with Sn-mordanting was worst. 4. Washing fastness and light fastness was excellent in various dyeing condition at silk fabric but cotton was without practical use.

• Journal of Biomedical Engineering Research
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• v.35 no.3
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• pp.62-67
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• 2014

The purpose of the study was to identify the effect of laser parameters on photocoagulation to maximize safety and efficacy during varicose vein treatment. CW and pulsed modes at 1470 nm were initially compared as a function of power on bovine liver tissue. In the pulsed mode, various parameters including repetition rate, duty cycle, and irradiation time were compared to evaluate tissue response during thermal treatment. The results demonstrated that CW and pulsed modes yielded almost similar coagulation development possibly due to shorter irradiation time of 5 sec. Regardless of laser mode, both repetition rate and duty cycle presented constant coagulation rate whereas longer irradiation time facilitated coagulation process.

• Journal of the Korea Safety Management & Science
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• v.11 no.3
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• pp.33-40
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• 2009

Steel and iron manufacture works exist that many latency risk as melting liquid of high temperature, work of high place, and so on. Once in a while, the accident case make use of basic data for latency risk analysis in a place of business. In this paper, we investigated the cause of the accident in steel an iron works. The result, we came across that many latency risk in steel and iron manufacture works. The main type of risk are fall, narrow, come flying, etc. Most of the latency risk type are repetition and conventional accident. Accordingly, steel and manufacture works must prevent to repetition and conventional accident.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.507-510
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• 2005

High voltage pulse power supply using Marx generator and solid-state switches is proposed in this study. The Marx generator is composed of 12 stages and each stage is made of IGBT stack, two diode stacks, and capacitor. To charge the capacitors of each stage in parallel, inductive charging method is used and this method results in high efficiency and high repetition rates. It can generate the pulse voltage with the following parameters: Voltage: up to 120kv Rising time: sub ${\mu}S$ Pulse width: up to $10{\mu}S$, Pulse repetition rate: 1000pps The proposed pulsed power generator uses IGBT stack with a simple driver and has modular design. So this system structure gives compactness and easiness to implement total system. Some experimental results are included to verify the system performances in this paper.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.4
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• pp.152-154
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• 2005

We demonstrate a simple $CO_2$ laser by controlling firing angle of a TRIAC switch in ac power line. The power supply for our laser system switches the voltage of the AC power line (60Hz) directly. The power supply does not need elements such as a rectifier bridge, energy-storage capacitors, or a current-limiting resistor in the discharge circuit. In order to control the laser output power, the pulse repetition rate is adjusted up to 60Hz and the firing angle of TRIAC gate is varied from $45^{circ}$ to $135^{circ}$. A ZCS(Zero Crossing Switch) circuit and a PIC one-chip microprocessor are used to control the gate signal of the TRIAC precisely. The maximum laser output of 40W is obtained at a total pressure of 18 Torr, a pulse repetition rate of 60Hz, and a TRAIC gate firing angle of $90^{circ}$.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.4
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• pp.158-163
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• 2002

The pulsed Power system has been widely used to many applications, such as E/P(Electrostatic Precipitator), DeNOx/DeSOx power system, often generator, etc. In this paper, we study EMTP analysis and characteristics of critical voltage and load in impedance on various electrode length of pulse corona. To obtain a stable pulse voltage, we designed a compact pulse generator switched MOSFET and tested their characteristics by adjusting electrode length and pulse repetition. As a re sult, critical voltage of pulse corona and load impedance on increasing electrode length were decreased. These results indicate we can control critical voltage of pulse corona and suppress arc discharging between two electrodes.