• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.70-77
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• 2013

We suggest a low area and high efficiency switched-mode power supply (SMPS) with a pulse width modulation (PWM) generator based on a pseudo relaxation-oscillating technique. In the proposed circuit, the PWM duty ratio is determined by the voltage slope control of an internal capacitor according to amount of charging current in a PWM generator. Compared to conventional SMPSs, the proposed control method consists of a simple structure without the filter circuits needed for an analog-controlled SMPS or the digital compensator used by a digitally-controlled SMPS. The proposed circuit is able to operate at switching frequency of 1MHz~10MHz, as this frequency can be controlled from the selection of one of the internal capacitors in a PWM generator. The maximum current of the core circuit is 2.7 mA, and the total current of the entire circuit including output buffer driver is 15 mA at 10 MHz switching frequency. The proposed SMPS has a simulated maximum ripple voltage of 7mV. In this paper, to verify the operation of the proposed circuit, we performed simulation using Dongbu Hitek BCD $0.35{\mu}m$ technology and measured the proposed circuit.

• Korean Journal of Veterinary Research
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• v.35 no.2
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• pp.279-285
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• 1995

To characterize non-adrenergic non-cholinergic(NANC) nerve mediated contractile responses in circular smooth muscle of bovine reticular groove, we investigated NANC relaxation and contraction induced by electric field stimulation to enteric nerves. In the presence of atropine($1{\mu}M$) and guanethidine($50{\mu}M$), electric field stimulation at frequency of 1 to 16Hz(square pulses, 0.5ms duration, 70V) evoked clear-cut relaxations through stimulations. Transient 'rebound contraction' was occured when the stimulus was switched off. All of the responses (relaxation and rebound contraction) were dose-dependently blocked by Nw-nitro-$_{\small{L}}$-arginine methyl ester(L-NAME), an inhibitor of nitric oxide synthesis, and methylene blue, and inhibitor of soluble guanylate cyclase. Tetraethyl ammonium(TEA), a potassium channel blocker, did not block the NANC relaxations.

• Journal of Korean Academy of Nursing
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• v.34 no.2
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• pp.213-224
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• 2004

Purpose: This study was aimed to evaluate the effect of progressive muscle relaxation training using biofeedback on perceived stress, stress response, immune response and climacteric symptoms, Method: This was a crossover, pre-post test design, The study subjects are 36 middle-aged women who were selected at 2 public health centers, The independent variable was Biofeedback training for 4 weeks, twice a week and home training for 4 weeks, Dependent variables were perceived stress, stress response, immune response, and climacteric symptoms measured with Hildtch's scale (1996), Result: Progressive muscle relaxation training using biofeedback was not effective in reducing perceived stress, but it was shown to be effective in reducing physiological stress responses such as pulse rate and EMG, Though blood pressure and skin conductance were repeatedly down, and skin temperature slowly increased, there were no statistically significant differences. Progressive muscle relaxation training using biofeedback was not effective in reducing serum cortisol, enhancing immune responses, or decreasing climacteric symptoms. Conclusion: The findings point to a pressing need for further, well-controlled and designed research with consideration in selection of subjects and instruments, frequency of measurements, the sampling method, and intervention modalities.

• Bulletin of the Korean Chemical Society
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• v.27 no.12
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• pp.2040-2044
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• 2006

Dielectric studies of methyl acrylate with 1-propanol, 1-butanol, 1-heptanol and 1-octanol binary mixtures have been carried out over the frequency range from 10 MHz to 10 GHz at temperatures of 283, 293, 303 and 313 K using Time Domain Reflectometry (TDR) for various concentrations. The Kirkwood correlation factor and excess inverse relaxation time were determined and discussed to yield information on the molecular structure and dynamics of the mixture. The values of the static dielectric constant, relaxation time and the Kirkwood correlation factor decrease with increased concentration of methyl acrylate in alcohol. The Bruggman plot shows a non-linearity of the curves for all the systems studied indicates the heterointeraction which may be due to hydrogen bonding of the OH group of alcohol with C=O of the methyl acrylate. The excess inverse relaxation time values are negative for all the systems at all the temperatures indicates that the solute-solvent interaction hinders the rotation of the dipoles of the system.

• Journal of Haehwa Medicine
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• v.22 no.2
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• pp.81-92
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• 2014

Objective : The purpose of this study was to assess the effects of Cyperus rotundus L. essential oil on relaxation in highly stressed volunteers with heart rate variability(HRV) and electroencephalography(EEG). Methods : 11 highly stressed volunteers participated in this study. The volunteers were examined with HRV and EEG before and after inhalation of Cyperus rotundus L. essential oil. Results : After smelling Cyperus rotundus L. essential oil, mean RR(mean of RR intervals) was incresed significantly(p<0.01), mean HRV(mean of heart rate), HF(high frequency) were decreased significantly(p<0.01). norm LF(low frequency), LF/HF ratio were decreased significantly(p<0.05), norm HF(normalized high frequency) was increased significantly(p<0.05) on HRV. After smelling Cyperus rotundus L. essential oil, relative ${\theta}$ power was decreased significantly(p<0.05) at P3(left parietal) and relative ${\alpha}$ power was increased significantly(p<0.05) at Fp1(left prefrontal), Fp2(right prefrontal) and relative ${\beta}$ power was decreased significantly(p<0.05) at Fp1(left prefrontal) and relative ${\gamma}$ power was decreased significantly(p<0.05) at Fp1(left prefrontal) on EEG. Conclusions : This results show that inhalation of Cyperus rotundus L. essential oil effects on relaxation and decreasing stress.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.4
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• pp.15-24
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• 2000

The dielectric relaxation of high-dielectric capacitors could be understood as a dynamic property of the capacitor in the time domain, which is regarded as a primarily important charge loss mechanism during the refresh time of DRAMs. Therefore, the equivalent circuit of the dielectric relaxation of the high-dielectric capacitor is essentially required to investigate its effects on DRAM. Nevertheless, There is not any theoretical method which is generally applied to realize the equivalent circuit of the dielectric relaxation. Recently, we have developed a novel procedure for the circuit modeling of the dielectric relaxation of high-dielectric capacitor utilizing the frequency domain. This procedure is a general method based on theoretical approach. We have also verified the feasibility of this procedure through experimental process. Finally, we successfully investigated the effect of dielectric relaxation on DRAM operation with the obtained equivalent circuit through this new method.

• Korean Journal of Veterinary Research
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• v.36 no.3
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• pp.599-605
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• 1996

This study was designed to examine the mechanism of penile erection in adult bull by analyzing the responses of bovine proximal retractor penile muscle strips(BRP) to electtical field stimulation(EFS), exogenous nitric oxide(NO), NO synthesis precursor(L-arginine), NO synthase inhibitors(L-NAME, L-NMMA), guanylate cyclase inhibitor(methylene blue) and nonspecific potassium channel blocker(tetraethylammonium, TEA) treatments. Isometric tension of BRP was measured using physiograph. Results were summarized as follows: 1. EFS of nonadrenergic noncholinrgic(NANC) nerve in BRP produced frequency-dependent inhibitory responses to the contraction induced by co-treatment of epinephrine, guanethidine and atropine. The inhibitory responses to EFS were blocked by tetrodotoxin(TTX, $1{\mu}M$). 2. Treatment of L-NAME ($10,\;20{\mu}M$) inhibited the relaxation to EFS whereas L-NMMA ($100{\mu}M$) had no effect. 3. Treatment of NO($20,\;40{\mu}M$; as an acidified solution of $NaNO_2$) induced concentration-dependent relaxation whereas preincubation of TTX($1{\mu}M$) and L-NAME($20{\mu}M$) had no effect on the relaxation response. 4. L-arginine treatment(10mM) blocked the inhibitory effect of L-NAME($20{\mu}M$). 5. Pretreatment of methylene blue($40{\mu}M$) reduced the NANC-induced relaxation of BRP. 6. Tetraethylammonium(TEA, 80mM) reduced NANC relaxation. These results suggest that NO may act as a NANC neurotransmitter in BRP and the effects might be mediated by cGMP and potassium channel.

• Korean Journal of Veterinary Research
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• v.28 no.1
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• pp.37-47
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• 1988

Xylazine hydrochloride is a widely used analgesic, sedative and muscle relaxant agent in veterinary clinic. Yohimbine hydrochloride and 4-aminopyridine are known as antagonists of xylazine hydrochloride. This paper was investigated to know that the effect of xylazine hydrochloride, yohimbine hydrochloride and 4-aminopyridine, and that whether or not antagonism of yohimbine hydrochloride and 4-aminopyridine to xylazine hydrochloride-induced effect on gizzard motility in chicken. The results were as follows. 1. After xylazine hydrochloride administration, the gizzard motility in chicken was instantly inhibited in relaxation state, and this state was prolonged in proportion to increase of dose. 2. After yohimbine hydrochloride administration, the gizzard motility in chicken showed increase of contractile frequency. 3. After 4-aminopyridine administration, the gizzard motility in chicken was gradually recovered next to decrease of contractile amplitude and frequency. 4. After the combination of yohimbine hydrochloride and 4-aminopyridine administration, the gizzard motility in chicken showed increase of amplitude and radical increase of frequency. 5. After xylazine hydrochloride administration, the relaxation time was shortened by yohimbine hydrochloride, 4-aminopyridine and the combination of yohimbine hydrochloride and 4-aminopyridine. In conclusion, the gizzard motility in chicken was inhibited by xylazine hydrochloride, and this effect was antagonized by the combination of yohimbine hydrochloride and 4-aminopyridine.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.11
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• pp.1007-1013
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• 1998

In this paper, the dielectric properties of fabricated Polyvinylidene fluoride(PVDF, $PVF_2$) thin film with substrate temperature from 30 to at vapor deposition. The dielectric properties of PVDF thin film had been studied in the frequency range from 10Hz to 4MHz at measuring temperature between 20 and $100^{/circ}C$. The anomalous increasing in dielectric constant and dielectric loss at low frequencies and high temperature was described for PVDF thin film containing ion impurities. In particularly, ion mobility of fabricated PVDF thin film at substrate temperature at $30^{/circ}C$ decrease from $2\times10^{-5}\;to\;3.07$\times10^{-7}cm^2/V.s$ On the other hand, ion density increase abruptly from 1.49\times$$10^{13}$ to $1.5\times$10^{16}$cm^{-3}$ In spite of decreasing of ion mobility, dielectric constants and dielectric loss for PVDF thin film increase rapidly with decreasing frequency and high temperature. It was concluded that the dielectric constants and dielectric loss was related to ion density than to ion mobility at low frequency and high temperatures.

• The Korean Journal of Physiology
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• v.21 no.2
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• pp.179-189
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• 1987

Since it has been known that ryanodine has a potent negative inotropic effect on the cardiac muscle contractility (Jenden and Fairhurst, 1968), ryanodine has been a subject of intensive research (Frank and Sleator, 1975; Jones et al, 1978; Sutko et al, 1985). However, the underlying mechanism for the ryanodine dependent negative inotropic effect is still uncertain. In this study, the effects of ryanodine on the generation and relaxation of contracture due to Na-withdrawal and on the force-frequency relationship of heart muscles isolated from rats and guinea pigs were measured in an effort to understand the underlying mechanism of the ryanodine-induced negative inotropy. Results are summerized as follows: 1 ) Ryanodine significantly reduced the contractility of heart muscles produced at low frequency of stimulation, but showed a little effect on the contractility at high frequency stimulation. 2) Ryanodine, at the concentrations ranging from $10^{-6}\;M$ to $10^{-8}\;M$, had no significant effect on the Na-dependent relaxation of Na-withdrawl contracture. 3) Ryandoine significantly reduced the amplitude of the Na-withdrawl contracture, and this inhibitory effect was reinforced by procaine, antiagonized by caffeine and high potassium. From these results, it may be concluded that the negative inotropic effect of ryanodine is mainly due to an inhibition of calcium release from sarcoplasmic reticulum.