• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2685-2692
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• 2009

We propose pulsed magnetic stimulation below 30W by the AC(60Hz) switching control of leakage transformer primary which has some advantage of cost and size compared to a typical pulsed power supply. Pulse repetition rate is adjusted from 5Hz to 60Hz to control magnetic stimulation output. In this magnetic stimulation, a low voltage open loop control for high voltage discharge circuit is employed to avoid the HV sampling or switching and high voltage leakage transformer is used to convert rectified low voltage pulse to high voltage one. A ZCS(Zero Cross Switch)circuit and a DSP & FPGA are used to control gate signal of SCR precisely. The pulse repetition rate is limited by 60Hz due to the frequency of AC line and a high leakage inductance. The maximum magnetic stimulation output was obtained about 33W at pulse repetition rate of 60Hz, total 40, 80, 120, $160^{\circ}$, SCR gate trigger angle $90^{\circ}$ and total output.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.273-274
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• 2018

플라이애시를 콘크리트의 혼화재로서 사용하기 위해서는 미연탄소 제거 및 알칼리 자극제의 첨가가 요구된다. 이러한 문제점을 해결하기 위해 현재까지 플라즈마를 이용한 플라이애시의 표면개질에 관한 연구가 진행되었으나, 플라즈마는 오존을 생성하는 문제점을 지니고 있다. 따라서 본 연구에서는 이와 같은 문제점을 해결하고자 아크방전을 이용해 플라이애시의 표면을 개질하는 연구를 진행하였다.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.22-28
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• 1996

From the experimental study of Wire-Cut Electric Discharge Machining of STD-11 alloy steel and P-20 tungsten carbide, the characteristics such as hand drum form and discharge gap have been observed and evaluated for various conditions. Hand drum form can be improved when gap have been observed and evaluated for various conditions. Hand drum form can be improved when gap voltage and spark cycle become smaller, thickness become thinner, wire tension become larger and the no of cutting increases. When 60mm thickness tungsten carbide is cut in normal condition, hand drum form becomes larger due to the low conductivity machining allowance become slightly larger when peak discharge current and gap voltage become larger, or wire tension becomes smaller. Under the same condition, machining allowance of tungsten carbide is larger than alloyed steel by 1/100mm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.325-328
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• 2009

In this study, A Magnetic stimulation Pulse Train control technique is introduced and applied to Flyback converter operating in discontinuous conduction mode. In contrast to the conventional pulse width modulation control scheme, the principal idea of a Magnetic stimulation Pulse Train is to achieve output voltage regulation using high and low power pulses. The proposed technique is applicable to any converter operating in discontinuous conduction. However, this work mainly focuses on Flyback topology. In this paper, the main mathematical concept of the new control algorithm is introduced and simulations as well as experimental results are presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.729-736
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• 2010

In this study, a magnetic stimulation (MS) device with controllable pulse forming technology and pulse shape (MS) is described. The MS device uses an IGBT with appropriate snubbers to switch coil currents up to 6 kA, enabling pulse forming technology control from 5 s to over 100 s. The induced electric field pulses use 2% - 34% less energy and generate 57% - 67% less coil heating compared to matched conventional cosine pulses. MS is used to stimulate rhesus monkey motor cortex in vivo with pulse forming technology of 20 to 100 s, demonstrating the expected decrease of threshold pulse amplitude with increasing pulse forming technology. The technological solutions used in the MS prototype can expand functionality, and reduce power consumption and coil heating in MS, enhancing its research and therapeutic applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.12
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• pp.2335-2342
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• 2007

Laser stimulation has been widely studied and used in clinic. However, electrical response by laser stimulation on meridians has not been investigated. In this study, we compared electric potential of laser and acupuncture stimulation on meridians. We measured electric potential variation at acupoints(Samgan(LI3) and Hapgok(LI4)) on Large Intestine Meridian. In laser stimulation results, average peak electric potential is very low($7.53{\pm}3.44{\mu}V$) for before and after stimulation. However, acupuncture stimulation was performed in ground connection condition and resulted in huge variation of average peak electric potential($2.65{\pm}1.53mV$). That is, the intensity and pattern of electric potential were dependent on the ground connection condition and individual. Also, the electric potential pattern was very similar to the pattern of electric charge and discharge of capacitor. The acupuncture stimulation using a insulating needle resulted in lower average peak electric potential variation($0.25{\pm}0.16mV$) than that of acupuncture stimulation. It might present little electrical response of acupuncture stimulation using insulating needles. In point of electrical response, the laser stimulation was determined to be no acupuncture effect at meridian. Acupuncture stimulation seems to be most effective method to induce electrical response at meridians. The procedure and effect of acupuncture might be considered as energy consensus phenomenon by transportation of bio-ion charge between a practitioner and patient.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1399-1410
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• 2009

It is a method to treat pain using medication, neurotomy, and surgery. And acupuncture, ultrasound, electric treatment, and magnetic treatment are applied as a alternative physiotherapy. Electronic therapy is useful but it can be affected by impedance of skin or subcutaneous tissue. So, percutaneous stimulation is leading therapy, that is very randomly. We developed the system which can stimulate parts of acupuncture point noninvasively using the focused magnetic field. And we designed the magnetic stimulation electrode which is considered efficiency of the magnetic stimulation. It can make similar stimulation with manual acupuncture. To confirm the availability and reliability we compared Meridian Electronic Potential(MEP) change between manual acupuncture and magnetic stimulation. From this result, we found out the MEP changes of manual acupuncture and magnetic stimulation were similar. And there were various response properties as changes of stimulation method, intensity, and frequency. Also, the MEP change can be induced by electromagnetic stimulation. We confirmed that it is possible to use electromagnetic stimulation as a acupoint stimulation or pain treatment instrument.

• The Journal of Information Technology
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• v.6 no.1
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• pp.65-70
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• 2003

In this papers, we proposed the new method in order to diagnosis partial discharge type of transformers. For wavelet transform, Daubechie's filter is used,, we can obtain wavelet coefficients which is used to extract featrue of statistical parameters(maximum value, average value, dispersion, skewness, kurtosis) about high frequency current signal per 3-electrode type(needle-plane electrode, IEC electrode and Void electrode). Also, these coefficients are used to identify signal of internal partial discharge in transformer. As a result, from compare of high frequency current signal amplitude and average value, we are obtained results of IEC electrode> Void electrode> Needle-Plane electrode. Otherwise, in case of skewness and kurtosis, we are obtained results of Void electrode> IEC electrode> Needle-Plane electrode. As improved method in order to diagnosis partial discharge type of transformers, we use neural network.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.209.1-209.1
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• 2016

우리에게 잘 알려져 있지 않은 강장동물 히드라는 뛰어난 세포 분열 능력을 가지고 있다. 출아(무성생식)를 하면서도 환경에 따라 유성생식을 하기도 하는 몇 안 되는 생물 중 하나인 히드라는 재생능력이 강하여 몸의 200분의 1만 잘려도 재생을 할 수 있는 능력을 가지고 있다. 이러한 히드라의 재생능력을 높은 에너지인 플라즈마에 노출시켜 보았다. 플라즈마는 열, 빛, 화학 활성종, 이온, 전자를 발생하며 이 중 열 및 화학적 자극을 중심으로 관찰하였다. 생물이 수용할 수 있는 열에너지를 넘게 받는다면 그 성질이 변하는 점을 이용해 액체 방전소스를 이용하여 플라즈마의 열적인 효과를 주었고, DBD소스로는 약 염기를 띠는 라디칼(활성종)용액을 배양액으로 만들어 히드라에게 배양시켜 히드라의 생장능력 변화를 알아보았다. 생장능력의 변화는 히드라의 개체 수를 통해 관찰하였다. 플라즈마를 발생시키는 소스는 다양하며 그 중 이번 실험에서는 액체 방전 소스와 DBD를 이용하였다. 액체방전 소스는 누전을 막기 위해 세라믹 관에 금속선을 넣어 고전압을 인가하여 방전하였고, DBD(Dielectric Barrier Discharge의 약어)는 유전체 장벽을 이용하여 기체를 방전시키는 방식이다. DBD는 주로 살균 용도로 연구 중이며, DBD는 주변 기체들을 반응시켜 라디칼을 상당히 만들어 낼 수가 있다. 한편, 생물학에서 주목 받고 있는 히드라는 200분의 1만 잘려도 재생이 되는 재생능력을 갖고 있다. 히드라의 이러한 생장 및 재생속도는 생체모방 기술로도 주목을 받고 있다. 이번 실험은 최근 연구되고 있는 플라즈마의 효과를 히드라에 적용한 것으로 플라즈마의 간접적인 영향이 히드라에 어떠한 영향을 줄 것인지 알아보았다. 간접적인 영향으로는 크게 열적인 요인과 화학적인 요인으로 나누어 관찰하였다. 실험을 통해 히드라의 변화를 알아보고 그 결과가 실용가능한지를 알아보고자 한다.

• Journal of Periodontal and Implant Science
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• v.34 no.3
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• pp.551-562
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• 2004

The purpose of this study was to evaluate the effects of negatively electric field on bone healing in rabbit segmental long bone defects using negatively charged PTFE membrane. Ten millimeter segmental defects in the rabbit radius were used as the experimental model. After membranes were then charge injected using a corona-charging apparatus, the left defects were covered with non charged PTFE membranes as control groups, whereas the right defect was covered with negatively charged PTFE membranes as test group. The animals were divided into 4 groups of 2 rabbits each, and sacrificed at 2, 4, 6, and 8 weeks. Histomorphometric analysis showed a more newly formed bone in negatively charged membrane at early healing period. At 2 weeks, the proportion of new bone formation to total defect area was 0.32% in control group, 1.10% in experimental group. At 4 weeks, the proportion of new bone formation to total defect area was 6.86% in control, and 13.75% in experimental. At 6 and 8 weeks, no obvious difference was found between the two groups but newly formed bone in test groups were slightly more than that in control groups. In conclusion, negatively charged membranes showed more newly bone tissue than noncharged membranes at an early healing period. Although the number of samples was small, this study showed that the combination of negatively electrical stimulation and P1FE membrane may be of value in long bone healing.