• 열처리공학회지
• /
• 제8권4호
• /
• pp.255-265
• /
• 1995

Stainless steel type 304L has been nitrided in the low pressure (600Pa) and high nitrogen (80% $N_2$+20% $H_2$) environment for 5 hours by the square-wave-pulsed-d.c. plasma as a function of temperature $400{\sim}550^{\circ}C$ and pulsation. At the lower temperature range of $400{\sim}500^{\circ}C$ and at the relatively high ratio of pulse duration to pulse period. "S-phase" has been developed in the form of thin nitrided surface layer which has many cracks, leading to be nearly impossible for the industrial anti-wear and anti-corrosion applications. At the higher temperature up to $550^{\circ}C$ with the increasing ratio of the pulse duration to pulse period up to $50{\mu}s/100{\mu}s$, the nitrided layer, whose growth rate has increased also, has been composed mainly of CrN and $Fe_4N$ phases and has become thick, uniform and nearly crack-free.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
• /
• pp.57-60
• /
• 2002

This paper deals with the effect of ramp-type erase pulse waveform on the high temperature driving characteristics of ac PDP driven by ramp up-down reset waveform. The experimental results show that the discharge characteristics in the reset period are significantly affected by the erase pulse waveform and ambient temperature. The firing voltage is increased with ambient temperature. This can cause misfirings during the sustain period and should be avoided. As one of possible solutions, we propose the optimization of erasing pulse shape.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 C
• /
• pp.1830-1833
• /
• 2002

We measured 3-dimensional temporal behavior of the light emitted from AC plasma display panel(PDP) at various auxiliary voltage pulse width supplied to the address electrode in sustain period using scanned point detecting system. In the case of applying an auxiliary address voltage pulse, the light emission starts at the inner edges of the cathode so the larger discharge volume toward address electrode can be obtained compared with the normal sustain discharge. Especially, when the auxiliary voltage pulse width is the $2{\mu}s$, the maximum luminance and long emission time can be obtained.

• Journal of Power Electronics
• /
• 제16권1호
• /
• pp.388-397
• /
• 2016

An error-compensated pulse width modulator (ECPWM) is proposed to improve the baseband harmonic performance and the switching loss of voltage source inverters (VSIs). Selecting between harmonic distortion and switching loss is a design tradeoff in the conventional space vector pulse width modulation. In this work, an accumulated difference in produced and desired phase voltages is considered to adjust the reference signal. This mechanism can compensate for the voltage error in the previous carrier period. With error compensation every half-carrier period, the proposed ECPWM allows one-half reduction in carrier frequency without scarifying baseband harmonic distortion. The proposed modulator is applied to a three-phase VSI with R-L load and a motor-speed-control system for experiments. The measured efficiency and operating temperature of switches confirm the effectiveness of the proposed scheme.

• 대한한방내과학회지
• /
• 제33권3호
• /
• pp.257-271
• /
• 2012

Objectives : The purpose of this study was to confirm that the pulse analyzer is useful for analyzing characteristics of variables of pulse waves in age categories, evaluating pulse waves of the metabolic syndrome group, compared with those of the non-metabolic syndrome group in Korean adults. Methods : The pulse wave variables were measured in Guan of all 1,056 subjects by the pulse analyzer, using a pen-type piezoresistive sensor. The physical measurement, blood test and survey were also performed by each subject. Results : In the age categories, height of pre-incisura (h2), height of tidal wave (h3), area of percussion wave (Aw), and width of percussion wave (w) increased in accordance with increase in age. While ratio of systolic period area (As) went up according to the increase of age, ratio of diastolic period area (Ad) went down. Radial augmentation index (R-AI), h2/h1, h3/h1, w/t and angle of percussion wave went up by aging, generally. Aw rate (Aw/At) also increased. Among the metabolic syndrome group, in the ages of 19 and 44, ratio of systolic period area (As) was higher and ratio of diastolic period area (Ad) was lower than in the non-metabolic group. w/t, Aw/At, and angle of percussion wave were higher than in the non-metabolic syndrome group. Among the metabolic syndrome group over the age of 60, height of pre-incisura (h2), height of tidal wave (h3), total area (At), area of percussion wave (Aw), radial augmentation index (R-AI), h2/h1 and h3/h1 were higher than in the non-metabolic syndrome group. Conclusions : The pulse analyzer is useful to analyze arterial stiffness in the age categories and in the metabolic syndrome group by some measures.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 제39회 하계학술대회
• /
• pp.1997-1998
• /
• 2008

Pulse diagnosis is the one of the most important diagnostic process to traditional medical doctors. Although the pulse diagnosis position, Gwan is apart from Chon or Cheok by 10$\sim$20mm at most, traditional medical doctors applies different indent pressures and even they states different pulse images are felt at Chon, Gwan and Cheok. One the other hand, the education on pulse diagnosis behavior includes tantalizing problem caused by no tool for communication between trainer and trainee. On account of this situation, we tried to develop a system which can measure the hold-down pressure during a pulse diagnosis and compare the hold-down pressure profile of trainer and that of trainee. This system can be divided into three parts - pulse pressure sensing part, signal acquisition part and data storing part. A correction curve was generated by the relation between output voltages and standard weights. Using this system, 3 channel hold-down pressure profile of a oriental medical doctor were recorded three times. In the profile, three period were observed and all period included two process for searching the depth of pulsation and for classifying the pulse feeling into one or more of 28 pulse types. The maximum value of pulse profile was 1.3$kg{\cdot}f$ which was more than reported by previous chinese groups and the mean values of three channel ranged from 240$g{\cdot}f$ to 430$g{\cdot}f$. In frequency domain, each channel has some dominant frequency components - about 10Hz, 35Hz and 75Hz. In further study, we want to collect more profiles from lage number of oriental medicine doctors and hope to develop a measuring system which can measure the hold-down pressure on subject's skin directly.

• 전기학회논문지
• /
• 제62권6호
• /
• pp.811-817
• /
• 2013

In this study we present a system for pulse-rate period detection and human sensibility evaluation based on the wireless medical telemetry service (WMTS) used for transmission of data from medical telemetry devices to various medical facilities and services. We develop a medical-purpose specific WMTS communication module to transmit biometric signals. From the pulse rate variability(PRV) signal, we attempt to classify positive and negative emotional states based on analysis of the ratio of LF/HF in the frequency domain. We measure the data reception rate according to distance in order to test the performance of the WMTS module and analyze the effects on human sensibility evaluation.

• 동의생리병리학회지
• /
• 제26권5호
• /
• pp.745-752
• /
• 2012

This study aims to show the change of Heart Rate Variability(HRV) and Pulse wave velocity(PWV) on menstruation in women at college. Heart Rate Variability(HRV) and Pulse wave velocity(PWV) of 122 women at college were measured at their menstruation and ordinary period. SDNN, RMSSD, SDSD, HRV Index(%), stress resistance and cardiac activity were significantly higher at their menstruation than ordinary period, but Total Power and pNN50(%) were opposite. The automatic nervous system balance and physical stress were decreased in groups without dysmenorrhea than with one. PWV(E-R) and PWV(E-L) were much higher at menstruation than ordinary period. PTT(F-R) and PTT(F-L) were decreased in groups without dysmenorrhea than with severe one. We demonstrated that menstruation can effect on Heart Rate Variability and Pulse wave velocity and dysmenorrhea can cause the imbalance of autonomic nervous system.

• 국제물리치료학회지
• /
• 제5권2호
• /
• pp.752-756
• /
• 2014

This study investigated the effects of changes to the pulsation factor of pulsed direct currents on wound healing. Patients with a pressure ulcer at a care hospital for the elderly were randomly divided into three groups: Group 1 involved the application of $100{\mu}s$ in pulse duration, 10 ms in pulse period, 100 pps in a pulsation factor, 15 mA in pulse amplitude, and polarity red+ by using pulsed direct currents; Group 2 involved a change of pulse period to 8 ms; and Group 3 received general wound management. Although there were no statistically significant differences in the changing stages of pressure ulcers among the groups, all the groups dropped in numerical stages. In the two groups to which pulsed direct currents were applied, there was a statistically significant reduction in the stages of pressure ulcers from the initial assessment to the 12-week assessment (p<.05). Even though there were no statistically significant differences in changes to the area of pressure ulcers among the groups, a statistically significant decrease was found in pulsed direct current group 2 whose pulse period was shortened (p<.05). There was no difference in the healing rate of pressure ulcers among the groups, but it made a numerical increase in pulsed direct current group 1 and group 2 and a numerical decrease in group 3. There were no significant differences in the characteristics of those who had a full recovery among the groups. Those findings indicate that pulsed direct currents have positive effects on the wound healing of patients with a pressure ulcer and that a treatment with pulsed direct currents whose pulsation factor is raised by reducing the pulse duration is especially effective.

• Korean Journal of Acupuncture
• /
• 제27권2호
• /
• pp.107-120
• /
• 2010

Objectives : The aim of this study is to measure pulse waveforms by applying 5-level graded pressure, and selecting optimum pulse waveforms. Also to proposing the possibility of using AW(Area of the 1/3 upper height of h1) rate in respect to AT(Total Area) for risk assessment of hypertension or arteriosclerosis is another aim of the study. Methods : Pulse waveforms of normotensive were measured by 5-level graded pressure. The pulse waveforms well reflecting properties of blood vessel(having the largest h1) were selected for optimum pulse waveforms. Various parameters(h-parameter, t-parameter, and others) of optimum pulse waveforms were analyzed. AIx(Augmentation index) was calculated by height-parameters to assess arterial stiffness. The area rate of the 1/3 upper height for h1 in respect to total area was analyzed according to aging. Results : According to aging 1. in height-parameter, h2 and h3 were increased but h5 was decreased. 2. In time-parameter, t2, t3, and t5 were getting short. 3. Area of systolic period was increased, and that of diastolic period decreased. 4. AIx rose by aging. 5. AW was significantly increased despite no changes in AT. Conclusions : By analyzing optimum pulse waveforms of 5-level graded pressure method, we could complement weakness of single graded pressure method. Also, possibility of applying the AW rate to risk assessment of hypertension or arteriosclerosis was confirmed in normotensive population which might not be assessed by AIx.