• The Korean Journal of Physiology and Pharmacology
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• v.25 no.6
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• pp.525-532
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• 2021

We have investigated the relative roles of α₁-adrenoceptors and purinoceptors in contractions to low and high frequency stimulation of the mouse vas deferens, in terms of the time course of responses. In separate experiments, isometric contractile responses were obtained to 10 pulses at 1 Hz and 40 pulses at 10 Hz. Responses to 1 Hz stimulation consisted of a series of discrete peaks. The α_1A-adrenoceptor antagonist RS100329 (10^-9M-10^-7M) significantly reduced the response to the first pulse, the α_1D-adrenoceptor antagonist BMY7378 (10^-7M-10^-6M) significantly reduced the response to the first two pulses, and the non-selective α₁-adrenoceptor antagonist prazosin (10^-8M) reduced the response to the first 4 pulses at 1 Hz. Responses to 10 Hz stimulation consisted of an early peak response and a maintained plateau response. RS100329 significantly reduced the peak response but did not significantly affect the plateau response. Prazosin, significantly reduced both the peak and plateau responses. The α_1A-adrenoceptor antagonist RS17053 in high concentrations reduced mainly the plateau response leaving a clear early peak response. The plateau response of contraction was almost abolished by the purinoceptor antagonist suramin. These results suggest that there is a relatively minor early α_1D-adrenoceptor and a larger early α_1A-adrenoceptor component to stimulationevoked contractions of mouse vas deferens, but the major α₁-adrenoceptor component is revealed by prazosin to be α_1B-adrenoceptor mediated. α_1B-Adrenoceptor activation probably facilitates contractions mediated by other α₁-adrenoceptors and by purinoceptors. These results suggest that combined non-selective α₁-adrenoceptor blockade, particularly α_1B-adrenoceptor blockade, in addition to P2X1-purinoceptor blockade is useful in reducing male fertility.

• Korean Journal of Environmental Agriculture
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• v.41 no.3
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• pp.206-216
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• 2022

BACKGROUND: Dithiocarbamate fungicide propineb can be analyzed quantitatively by derivatization reaction followed by HPLC/UVD, which has high reproducibility and stability. However, the presence of high protein in soybeans and peas affects the derivatization process resulting in extremely low recoveries. Therefore, this study was conducted to improve the analytical method for analysis of propineb in soybeans and peas by applying a deproteinization process using chloroform-gel method. METHODS AND RESULTS: The deproteinization process was carried out up to 6 times for soybeans and 5 times for peas using 50 mL chloroform. After 4 times of deproteinization process followed by a derivatization reaction with methyl iodide, the recovery yields of propineb in both pulses were >90%. However, the recovery yield tended to decrease when the deproteinization process was performed more than 5 times. The method limit of quantification (LOQ) was 0.04 mg/L. The recovery conducted in triplicate at 10 times and 50 times of the LOQ ranged from 87.2 to 95.0 % with a coefficient of variation <10%. CONCLUSION(S): This study confirmed that 4 times of deproteinization process using the chloroform-gel method was effective when derivatizing and analyzing dithiocarbamate fungicides in pulses with high protein content. However, depending on the initial protein content present in the pulses, there was a difference in the recovery: the lower the protein content, the higher the recovery rate of propineb. It is expected that the method proposed in this study could be applied to remove high content of protein as analytical interference substance from agricultural samples.

• Journal of the Korean Society of Safety
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• v.14 no.1
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• pp.216-221
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• 1999

The correlation between propagation of electrical tree and internal partial discharges is discussed. We use specimens with needle-plane electrode system made of LDPE(Low Density Polyethylene), observed inception and propagation of electrical tree by optical microscope and investigated the characteristics of the partial discharge (PD) pulses accompanying with propagation of electrical tree. In the specimens with needle-shaped void, the tree propagates branch type. The length of the tree has good linear relation with average discharge power of PD pulses. In the specimens without needle-shaped void, the tree grows bush type tree. The correlation between the area of the tree and the average discharge power of PD pulses has linear relation.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.6
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• pp.541-553
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• 2023

Retinal prostheses have shown some clinical success in restoring vision in patients with retinitis pigmentosa. However, the post-implantation visual acuity does not exceed that of legal blindness. The reason for the poor visual acuity might be that (1) degenerate retinal ganglion cells (RGCs) are less responsive to electrical stimulation than normal RGCs, and (2) electrically-evoked RGC spikes show a more widespread not focal response. The single-biphasic pulse electrical stimulation, commonly used in artificial vision, has limitations in addressing these issues. In this study, we propose the benefit of multiple consecutive-biphasic pulse stimulation. We used C57BL/6J mice and C3H/HeJ (rd1) mice for the normal retina and retinal degeneration model. An 8 × 8 multi-electrode array was used to record electrically-evoked RGC spikes. We compared RGC responses when increasing the amplitude of a single biphasic pulse versus increasing the number of consecutive biphasic pulses at the same stimulus charge. Increasing the amplitude of a single biphasic pulse induced more RGC spike firing while the spatial resolution of RGC populations decreased. For multiple consecutive-biphasic pulse stimulation, RGC firing increased as the number of pulses increased, and the spatial resolution of RGC populations was well preserved even up to 5 pulses. Multiple consecutive-biphasic pulse stimulation using two or three pulses in degenerate retinas induced as much RGC spike firing as in normal retinas. These findings suggest that the newly proposed multiple consecutive-biphasic pulse stimulation can improve the visual acuity in prosthesis-implanted patients.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.2
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• pp.194-204
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• 2002

In this paper, a new two-phase space vector RPWM(Random PWM) is proposed. In the proposed RPWM, each of two-phase PWM pulses is located randomly in each switching interval. Based on the space vector modulation technique, the duty ratio of the pulses is calculated. Along with the randomization of the PWM pulses, we can obtain the effects of spread spectra of inverter output voltage, d.c link current and audible switching acoustic noise as in the case of randomly changed switching frequency. To verily the validity of the proposed two-phase RPWM scheme, the experiment based on the Cl67 micro-controller was executed. The performance of the proposed scheme was compared with traditional PWM schemes experimentally.

• Journal of Korea Water Resources Association
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• v.39 no.9 s.170
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• pp.745-754
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• 2006

This study adopted the Rectangular Pulses Poisson Process Model for the drought severity-duration-frequency analysis to characterize the spatial pattern of drought over the Korean peninsula using the rainfall data of the 59 rain gauge stations. First of all, the drought severity in the southern part of the Korean peninsula was found to be generally high for any return period. This result is consistent for both cases with and without considering the overlap probability of rectangular pulses, which is also valid for longer durations. Comparison with those of observed drought frequency and maximum severity also showed that the result in this study has enough reliability.

• Journal of Korean Medical classics
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• v.12 no.2
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• pp.294-315
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• 1999

$\ll$靈樞 動輸$\gg$ explains the way that the Arm Greater um Lung meridian, the Leg lesser urn kidney meridian and the Leg Yang-Myong Stomach meridian are keeping incessant pulsation, and the relation that these three meridians transport ant irrigate around the whole body. And also, when the meridian lines have been obstructed, the ki travels via shortcuts, in the course of spreading outer ki and inner ki around the whole body. Concretely speaking, in the first mapter it is explained the way that the Arm Greater urn Lung meridian pulses incessantly, in the second chapter, it is explained the way that the Leg Yang-Myong stomach meridian pulses incessantly, in the third chapter, the Leg Lesser urn kidney meridian pulses incessantly and in the fourth chapter, the movement of inner and outer ki are explained. But this chapter has many ancient letters and many parts omitted, so it is too hard to understand directly. Therefore we set to work with the view of helping to understand the original text more accurately by the reference of several editions and many commentarists' fruitful researches.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.525-537
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• 2001

In this paper a new space vector RPPWM(Random Position PWM) is proposed. In the propsed RPPWM each of three phase pulses is located randomly in each switching interval. Based on the Space vector modulation technique the duty ratio of the pulses is calculated Along with the randomization of the PWM pulses. we can obtain the effects of spread spectra of votlage, current as in the case of randomly changed switching frequency, To verify the validity of the proposed RPPWM simulation study was tried using Matlab/Simulink The main model described in Simulink block diagrams includes the space vector modulation block pulse position randomization block inverter block 3 phase induction motor block and so on By the simulation study, the harmonics of the output voltage and the current of inverter are predicted in different PWM methods- SVPWM, LLPWM proposed RPPWM.

• Progress in Superconductivity
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• v.4 no.2
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• pp.127-131
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• 2003

We have designed and measured an SFQ(Single Flux Quantum) OR gate for a superconducting ALU (Arithmetic Logic Unit). To optimize the circuit, we used WRspice, XIC and Lmeter for simulations and layouts. The OR gate was consisted of a Confluence Buffer and a D Flip-Flop. When a pulse enters into the OR gate, the pulse does not propagate to the other input port because of the Confluence Buffer. A role of D Flip-Flip is expelling the data when the clock is entered into D Flip-Flop. For the measurement of the OR gate operation, we attached three DC/SFQs, three SFQ/DCs and one RS Flip -Flop to the OR gate. DC/SFQ circuits were used to generate the data pulses and clock pulses. Input frequency of 10kHz and 1MHzwere used to generate the SFQ pulses from DC/SFQ circuits. Output data from OR gate moved to RS flip -Flop to display the output on the oscilloscope. We obtained bias margins of the D Flip -Flop and the Confluence Buffer from the measurements. The measured bias margins $\pm$38.6% and $\pm$23.2% for D Flip-Flop and Confluence Buffer, respectively The circuit was measured at the liquid helium temperature.

• Korean Journal of Optics and Photonics
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• v.15 no.1
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• pp.46-50
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• 2004

Images were acquired by the modulation of terahertz electromagnetic signals and compared by modulation frequencies. For the real-time acquisition of images a fast scanning method has been adopted utilizing a galvanometer. The acquired time domain waveforms were transformed into frequency domain data by fast Fourier transformations (FFT). We chose some frequency components to compare the resolution of images. The beam profiles at the focal position were measured by a knife-edge technique. Beam diameter was shown to decrease as the frequency increased. By scanning one- and two-dimensional samples a significant image enhancement was observed with the frequency increment. A nondesouctive imaging system using ㎔ electromagnetic pulses was also demonstrated.