• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1022-1025
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• 2008

This paper presents the generation of the high voltage squarewave pulse using distributed RLC circuit. The demonstrated test was performed with the distributed RLC circuit which consists of the resistance, the inductance and the capacitance. Pspice simulation was also conducted about the experiment circuit. The result of the experiment was in good agreement with the result of the simulation. Theoretical analysis of the initial peak value at the squraewave pulse was derived from the results of the experiment and simulation. Additionally, the characteristics of the time delay was analyzed about the spherical gap switch and the surface discharge gap switch, respectively. It is concluded that the surface discharge gap switch is better than the spherical gap switch to reduce the time delay.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.1
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• pp.23-29
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• 1995

There are many articles about the HID lamps about it's characteristics and simulation methods for lamp design or ballast design. For the electronic ballasts of HID lamps, There are some problems caused by acoustic-resonance which destabilizes the arc of HID lamps. So, some studies suggest the methods to avoid it. For example, the methods suggested are high frequence driving over 100[kHz], and mixed frequence driving which alternates high frequence and low frequence, and squarewave driving etc. This study suggests the electronic ballast of HID lamps that solves the problems of acoustic-resonance, and can control the luminance by constant current boostes chopper of which frequence is 30[kHz] and by the squarewave driving of which frequence is 55.5[Hz.] As follows, we have the good electronic ballast for HID lamps which has the characteristics of a light weight, and a function of luminance control and a high quality luminosity and which saves electrical energy.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.801-809
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• 2013

We investigate sensitivity and limit of detection (LOD) of trace copper (Cu) metal using pristine carbon nanotube (CNT) and acidified CNT (ACNT) electrodes. Squarewave based anodic stripping voltammetry (SWASV) is used to determine the stripped Cu concentration. Prior to performing the SWASV measurements, its optimal conditions are determined and with that, effects of potential scan rate and $Cu^{2+}$ concentration on stripping current are evaluated. The measurements indicate that (1) ACNT electrode shows better results than CNT electrode and (2) stripping is controlled by surface reaction. In the given $Cu^{2+}$ concentration range of 25-150 ppb, peak stripping current has linearity with $Cu^{2+}$ concentration. Quantitatively, sensitivity and LOD of Cu in ACNT electrode are 9.36 ${\mu}A\;{\mu}M^{-1}$ and 3 ppb, while their values are 3.99 ${\mu}A\;{\mu}M^{-1}$ and 3 ppb with CNT electrode. We evaluate the effect of three different water solutions (deionized water, tap water and river water) on stripping current and the confirm types of water don't affect the sensitivity of Cu. It turns out by optical inspection and cyclic voltammetry that superiority of ACNT electrode to CNT electrode is attributed to exfoliation of CNT bundles and improved interfacial adhesion occurring during oxidation of CNTs.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.147-149
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• 2014

본 논문에서는 LED드라이버의 지속적인 과제인 고역률, 효율개선 및 장수명화를 위한 연구를 진행하였다. 전체적인 토폴로지는 역률개선 및 출력전류제어의 성능을 자세히 관찰하기 위하여 투 스테이지 토폴로지를 선정하였으며, 1차측은 고 효율을 위하여 Bridgeless타입의 Totem-Pole bridgeless rectifier를 선정하였으며, 2차측은 LED드라이버의 수명을 좌우하는 DC 커패시턴스를 줄이기 위한 전류제어를 하기 위하여 Flyback DC-DC컨버터 토폴로지를 적용하였다. 일반적인 투 스테이지 토폴로지와 본 논문에서 제안한 토폴로지의 시뮬레이션 및 실험을 통하여 성능적인 분석을 통하여 LED드라이버의 효율증대 및 수명증가에 대한 내용을 다루었다.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.933-937
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• 2012

In the present study, we evaluate the sensitivity and optimal stripping voltammetry (SV) conditions of copper (Cu), which is one of the main trace heavy metals inducing the environmental contamination, using carbon nanotube (CNT) electrode. In addition, the reaction mechanism of stripping reaction of Cu is investigated. The electrochemical analyses such as squarewave stripping voltammetry (SWSV) and linear scan voltammetry (LSV) are used for the evaluations. As a result of that, the best SWSV conditions like squarewave amplitude of 15 mV, frequency of 60 Hz, deposition potential of -1.0V vs. Ag/AgCl and deposition time of 200s are determined with the measured Cu sensitivity of $1.824{\mu}A/{\mu}M$. As a driving force affecting the stripping reaction of Cu, surface reaction is more dominant one than diffusion. These results are compared with other reference results and it is confirmed that our suggested CNT electrode gives rise to better Cu sensitivity result than other references.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.505-509
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• 2012

In this study, we investigate the use of new carbon nanotube paste electrode (CNPE) for promoting the detection of lead (Pb) heavy metal in the a drinkable water, which negatively affects human brain and nerve system. For the evaluations, CNPE is served as a working electrode, while sensitivity and limit of detection (LOD) of Pb are measured in DI and tap water based electrolytes using squarewave anodic stripping voltammetry (SWASV). As a result of that, in the 25~150 ppb range of $Pb^{2+}$ ions, its sensitivity and calculated LOD are $12.85\;{\mu}A/{\mu}M$ and 26 ppb in DI water based 0.1 M $H_{2}SO_{4}$ electrolyte while they are $10.36\;{\mu}A/{\mu}M$ and 38 ppb electrolytes respectively. In addition, experimentally measured LOD values of Pb are 4 ppb and 10 ppb in the two water electrolytes. The stripping of $Pb^{2+}$ ion is also controlled by surface reaction. Our experimental data are then compared with those of other already published references. With the comparison, it is proved that our electrode outperforms other electrodes in terms of the sensitivity and LOD of trace Pb metal.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.361-365
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• 2002

Advancements in silicon phase control (SCR) technologies provide an arc welding power supply that has the capability to allow the alteration of the Alternating Current (AC) welding output. These technologies provide a square wave output involving sixteen frequency selections and multiple balance selections. While an AC out put is known to minimize magnetic disturbances associate with Direct Current (DC), the potentials of a non-sinusoidal waveform have not been explored. The focus of the paper is to determine the effects that the frequency and balance of an AC wave form output will have upon a high speed Submerge Arc (SAW) application. The test matrix of the project includes welding .250" steel plate. Joint type is square groove with a travel speed of 65 IPM. Each of the weld parameters was held constant, only the frequency and/or balance were altered between welds. Each frequency/balance combination involved three-gap spacing. Upon completion of the welds the bead profiles were measured and recorded. A relationships/trends were observed with various frequency and balance values. Optimum frequency and balance values were found for the .250" square groove application which permit consistent weld sizing, ease of slag removal, and minimal plate distortion.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.447-450
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• 2002

A study on control of BLDC Is studying In progress, because of radical increase of survo motor at industrial machine and home machine. Nowaday, we study on control of BLDC, because of radical increase of survo motor at Industry and home. Although control ratio and output of the unit volume are good than the others , BLDC motor demands high cost. Therefor, the study on low cost BLDC have square wave back-emf is studing in progress. Therefor, BLDC Motor was studied to reduce high cost that have square wave back-emf at recently. This paper shows that BLDC Motor, developed highly responsility by using Genetic Algorithm(GA) that the advantages of learning ability, Also, this paper shows experiment and simulation at 200W BLDC that have squarewave back-emf by using Genetic Algorithm. At the result of this methods, the study prove experiment's right.

• Analytical Science and Technology
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• v.8 no.2
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• pp.171-179
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• 1995

This is an analytical study of germanium by adsorption stripping squarewave voltammetry. Tannic acid was used as a ligand. The accumulation potential was -0.2V, accumulation time was carried out for 60 second under constant stirring, followed by a 20 second quiescent period, and frequency was 10Hz. A hanging mercury drop electrode was used as a working electrode and acetate buffer solution, pH=4.5, as supporting electrolyte. The proper conditions of ligand for germanium analysis was established. The effect of metal ions(lead, cupper, silicon, tin, gallium) on germanium peak was also studied.