• Title/Summary/Keyword: pulse cycle

Search Result 300, Processing Time 0.28 seconds

Characterization of behaviors using electric pulse for phase switching operation of Ge2Sb2Te5 material

  • Lee, Hyeon-Cheol;Choe, Du-Jin
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • /
    • pp.322-322
    • /
    • 2016
  • Phase change memory (PCM) has attracted much attention as one of the most promising candidates for next-generation nonvolatile memory. In that regard, the purposes of the study are to propose reference of effective pulse parameter to control phase switching operation and to invest the effect of nitrogen doped in PCM materials for improved cycling stability and economic energy consumption. Switching operation of PCM is affected by electric pulse parameter and as shown in figure.1 are composed to RT(rising time), ST(setting time), FT(falling time) and the effect of these parameter was precisely investigated. Transmission electron microscope (TEM) was used to confirm fine structure and retention cycle test was conducted to confirm reliability. Finally improvement reliability and economic power consumption in quantitatively are obtainable by optimum pulse parameter and nitrogen doping in GST material. these study is related to the engineering background of other semiconductor industries and it have confirmed to possibility further applications.

  • PDF

A study of the output waveform of solid-state laser of multi-discharge method by various switching control (다수 스위칭 제어를 통한 Multi-Discharge방식의 고체레이저 출력파형 연구)

  • Kwak, S.Y.;Kim, S.G.;Hong, J.H.;Noh, K.K.;Kang, U.;Kim, H.J.
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.1852-1854
    • /
    • 2003
  • In manufacturing processes, various and suitable pulse shapes are required for the purpose of material processing. In order to make various pulse shapes with variable pulse length and high duty cycle, We have fabricated the power supply consisting 6 SCRs and the Pulse Forming Network(PFN) with the precise delay time control. So our control system has three switching circuits, 3 mesh PFN, and simmer circuit. In addition, we have designed and fabricated the PIC one-chip microprocessor(16F877) to control the delay time of sequential switching.

  • PDF

A Plastic Cortex Stimulator for Stroke Recovery Using ZigBee technology (ZigBee 무선통신 기술을 이용한 뇌졸중 환자 치료용 뇌자극기 개발)

  • Kim, G.H.;Yang, Y.S.;Lee, S.M.;Kim, N.G.
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.373-375
    • /
    • 2005
  • The purpose of this paper is to develop the Plastic Cortex Stimulator(PCS) for stroke patients using ZigBee technology. The PCS consists of an implantable neuro-stimulator and a user controller, The neuro-stimulator has the stimulus circuit which is the H-bridge circuit to generate a bipolar pulse. The bipolar pulse is known to be effective for stroke recovery. The user controller sends several wave-shape parameters (amplitude, pulse width, cycle, etc.) to the neuro-stimulator for variable stimulation using ZigBee technology. The CC2420 and atmega128L was used to implement ZigBee protocol stack. The wireless control of PCS based on ZigBee can help the tele-rehabilitation of the stroke patients. The most effective pulse shape parameters are being investigated through animal experiments. The bio-compatibility and user-friendly interface are supposed to be handled in further study.

  • PDF

Improved Randomized Pulse Position PWM Scheme Based on The three-phase Indui Drive To Reduce the Harmonic Effect (개선된 Randomized Pulse Position PWM기법을 이용한 3상 유도 전동기의 고조파 영향)

  • Ha, Sang-Mok;Han, Woo-Yong;Lee, Chang-Goo;Kim, Byung-Woo
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.1169-1171
    • /
    • 2002
  • In this paper, RFRPP(Random Frequency Randomized Pulse Position ) PWM for three-phase voltage-controlled inverters is proposed. The LLPWM(Lead-Lag PWM) techinquc is that three switching pulses are located randomly back and forth in each switching interval. But with the restriction of random distribution, the harmonic spectrum cannot be dispersedly and continuously distributed. This paper calculates the duty ratio of the switching pulse firstly. Second, the switching pulses are located randomly in the switching interval. Third, the fixed switching frequency of the space vector modulation is randomly varied. To verify the validity of the proposed technique, simulation study is tried using Matlab/Simulink. When a proposed techniquc is employed, the harmonic spectrum of the inverter output voltagc varies from one cycle to the next and the EMI(Electromagnetic Interference) and resonant vibration are greatly alleviated.

  • PDF

Effects of Electroplating Current Density and Duty Cycle on Nanocrystal Size and Film Hardness

  • Sun, Yong-Bin
    • Journal of the Semiconductor & Display Technology
    • /
    • v.14 no.1
    • /
    • pp.67-71
    • /
    • 2015
  • Pulse electroplating was studied to form nanocrystal structure effectively by changing plating current density and duty cycle. When both of plating current density and duty cycle were decreased from $100mA/cm^2$ and 70% to $50mA/cm^2$ and 30%, the P content in the Ni matrix was increased almost up to the composition of $Ni_3P$ compound and the grain growth after annealing was retarded as well. The as-plated hardness values ranging from 660 to 753 HV are mainly based on the formation of nanocrystal structure. On the other hand, the post-anneal hardness values ranging from 898 to 1045 HV, which are comparable to the hardness of hard Cr, are coming from how competition worked between the precipitation of $Ni_3P$ and the grain coarsening. According to the ANOVA and regression analysis, the plating current density showed more strong effect on nanocrystal size and film hardness than the duty cycle.

Half-Cycle-Waveform-Inversed Single-Carrier Seven-level Sinusoidal Modulation

  • Wu, Fengjiang;Sun, Bo;Zhang, Lujie;Sun, Li
    • Journal of Power Electronics
    • /
    • v.13 no.1
    • /
    • pp.86-93
    • /
    • 2013
  • A half-cycle-waveform inversion based three reference modulations seven-level SPWM (TRM-SPWM) scheme with one carrier is proposed in this paper. To keep the same comparison logics for the modulations and carrier during the negative half cycle and the positive one for the modulations, in the negative half cycle of the modulations, the DC offsets related to the amplitude of the carrier are set on the three modulations, respectively. The seven-level SPWM waveform with dead time thereby is implemented with only one Digital Signal Processor (DSP) without any other attached logic circuit. The basis principle of the proposed TRM-SPWM is analyzed in detail, and the frequency spectrums of the conventional and the proposed schemes are derived and compared with each other through simulation. The DSP based implementation is presented and detailed experimental waveforms verify the accuracy and feasibility of the proposed TRM-SPWM scheme.

Metal Drilling using Amplitude Modulated Laser Pulse (AM 변조된 레이저 펄스를 이용한 금속 Drilling)

  • Kim, Ho-Seong
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.1210-1212
    • /
    • 1994
  • An amplitude modulation technique for increasing the laser penetration efficiency for metals has been studied. By chopping electro-optically Nd:YAG laser pulse, the threshold energy for reliable hole drilling was decreased significantly and the penetration depth was increased. It was observed that the effect of chopping was optimal at 8-12 kHz with 60% duty cycle. It is believed that this improvement is due to an increase in the vapor recoil pressure and reduced plasma screening.

  • PDF

Effect of Laser Acupuncture on Arterial Pulse

  • Cho, Jaekyong;Kang, Dong Hwan
    • Journal of Biomedical Engineering Research
    • /
    • v.36 no.5
    • /
    • pp.191-197
    • /
    • 2015
  • Laser acupuncture is defined as the stimulation of traditional acupuncture points with low-intensity, nonthermal laser irradiation. Possible advantages in using laser acupuncture are the noninvasive, painless and low risks of infection treatment. The purpose of this study is to assess the effect of laser acupuncture on the quality and waveform of arterial pulses. Ten acupuncture points were stimulated repeatedly three times in 30 individuals by laser with emission in the near infrared spectral region (808 nm) using an out power and power density of 45 mW and $143W/cm^2$. The analysis of pulse quality and waveform was performed based on the measurement of arterial pressure of the left and right wrist, using a 3-dimensional blood pressure pulse analyzer. Excess-like pulse quality of subjects before laser acupuncture changed significantly to balanced pulse quality after 10, 20, and 30 minutes of laser acupuncture; coefficient of deficient or excess, $C_{DE}$, decreased significantly from 0.68 before acupuncture to 0.61, 0.55, and 0.55 after 10, 20, 30 minutes of laser acupuncture ($$p{\leq_-}0.006$$), respectively. Other pulse qualities, floating or sinking, slow or rapid, choppy or slippery did not change significantly by laser acupuncture (p > 0.05). Pulse waveform analysis showed that amplitude of main peak (systolic function or aortic compliance, $h_1$) of left and right artery pulse waves decreased significantly after 10, 20, and 30 minutes of laser acupuncture (p < 0.05). Other parameters, duration of one cardiac cycle (T), duration of rapid systolic ejection ($T_1$), duration of the systolic phase ($T_4$), and duration of the diastolic phase ($T_5$) of left and right artery pulses did not change significantly after laser acupuncture (p > 0.05).

A Study on the Performance of Pulse Jet Cleaning in High Temperature Filter (고온 세라믹필터의 펄스젯 탈진 성능에 관한 연구)

  • Kim Byong Ryol;Park Seung Chul;Park Byoung Chul;Cho Hynu Joon;Oh Hyoung Mo;Hwang Tae Won;Shin Sang Woon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
    • /
    • v.3 no.1
    • /
    • pp.9-16
    • /
    • 2005
  • To evaluate parameters influencing on the dust removal of the High Temperature Filter(HTF) system, a computer simulation of fluid dynamics inside the system had been performed. The results showed that the optimum pulse jet periods were 50ms and 90ms for the 1000mm and 1500mm long filter elements respectively. Dust removal effect was very excellent under the pulse jet pressure of 3 bar. But the distance between the pulse jet nozzle and the venturi of a filter element had no meaningful effect on the performance with the variation from 5mm to 10mm. Compared to the dispersion mode of pulse jet, the collective mode of pulse jet flow was preferable in maintaining the pressure inside the system stable.

  • PDF

Materials Properties of Nickel Electrodeposits as a Function of the Current Density, Duty Cycle, Temperature and pH

  • Kim, Dong-Jin;Kim, Myung Jin;Kim, Joung Soo;Kim, Hong Pyo
    • Corrosion Science and Technology
    • /
    • v.5 no.5
    • /
    • pp.168-172
    • /
    • 2006
  • Alloy 600 having a superior resistance to a corrosion is used as a steam generator tubing in nuclear power plants. In spite of its high corrosion resistance, there are many tubings which experience corrosion problems such as a SCC under the high temperature and high pressure environments of nuclear power plants. The Alloy 600 tubing can be repaired by using a Ni electroplating having an excellent SCC resistance. In order to carry out a successful Ni electrodeposition inside a steam generator tubing, the effects of various parameters on the material properties of the electrodeposit should be elucidated. Hence this work deals with the effects of an applied current density, duty cycle($T_{on}/(T_{on}+T_{off})$) of a pulse current, bath temperature and solution pH on the material properties of Ni electrodeposit obtained from a Ni sulphamate bath by analyzing the current efficiency, potentiodynamic curve, hardness and stress-strain curve. Hardness, YS(yield strength) and TS(tensile strength) decreased whereas the elongation increased as the applied current density increased. This was thought to be by a concentration depletion at the interface of the electrodeposit/solution, and a fractional decrease of the hydrogen reduction reaction. As the duty cycle increased, the hardness, YS and TS decreased while the elongation increased. During an off time at a high duty cycle, the concentration depletion could not be recovered sufficiently enough to induce a coarse grain sized electrodeposit. With an increase of the solution temperature and pH, the YS and TS increased while the elongation decreased. The experimental results of the hardness and the stress-strain curves can be supplemented by the results of the potentiodynamic curve.