• 터널과지하공간
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• 제20권5호
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• pp.325-331
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• 2010

이 연구에서는 사암 벤치에 대하여 V형과 경사 V형의 두 가지 기폭 패턴으로 대규모 발파를 실시하였다. 장약량은 비슷하였다. 발파 후 디지털 이미지 프로세싱 방법으로 파쇄석의 파쇄도를 평가하였다. 10 $m^3$ 용량 로우프 쇼벨의 싸이클 시간도 계측하였다. 그 결과는 경사 V형으로 기폭한 경우 파쇄성능이나 굴착기 성과가 더 향상된다는 것을 보여준다. 이 논문에서는 경사 V형 패턴이 V 형 패턴보다 더 나은 성능을 보이는 이유에 대하여 논한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.1322-1325
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• 1987

In this study, the excitation pattern, which can be sensated by a man having hearing loss due to the damage of inner ear, is extracted, and the procedure of the auditory speech signal processing is simulated with the computer. Therefore, the excitation pattern is extracted by the neural tuning model satisfying the physiological characteristic of the inner ear and by the infor.ation extracted from speech signal. The firing pattern is also extracted by inputting this excitation pattern to the auditory neural model. With this extracted firing pattern, the possibility that the patient can sensate the speech signal is studied by the computer simulation.

• The Korean Journal of Physiology
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• 제29권1호
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• pp.103-111
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• 1995

Intracellular recordings were obtained from Purkinje cells in rat cerebellar slices maintained in vitro. Adding tetrodotoxin to the superfusion solution produced a typical pattern of repetitive burst firing consisting of a cluster of action potentials followed by a long hyperpolarization. TTX-induced oscillatory activity was not due to modulation of membrane potential although underlying mechanisms for maintenance of oscillatory activity were influenced by membrane voltage. The mechanism of TTX-induced oscillation was not related to the presence or amplitude of $I_h$ and could still induce the oscillatory activity after blockade of $I_h$ by cesium. The result from an experiment in which QX-314 was injected intracellularly strongly suggested that TTX-induced oscillatory firing activity was due to blockade of post-synaptic $Na^{+}$ currents intrinsic to PCs.

• Journal of Power Electronics
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• 제19권6호
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• pp.1458-1466
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• 2019

Multilevel inverters have appeared as a successful and utilitarian solution in many power applications. The prime objective of an inverter is to keep the fundamental component of the output voltage of a multilevel inverter at a preferred value. Equally important is the need to keep the harmonic components in the output voltage within stated harmonic limits. Therefore, the basis of this research is to develop a harmonic minimization function that optimizes the switching angles of cascaded H-bridge multilevel inverter. Due to benefits of the Cuckoo Search (CS) algorithm, it is applied to determine the switching angles, which are further used to generate the switching pattern for firing the H-bridges of multilevel inverter. Simulation results are compared with SPWM based firing scheme. The switching frequency for SPWM firing scheme is taken as 200 Hz since the switching losses are increased when switching frequency is high. To validate the ability of Cuckoo Search optimized firing scheme in minimization of harmonics, experimental results obtained from hardware prototype of Five Level Cascaded H-Bridge Multilevel Inverter equipped with a FPGA controller are presented to verify the simulation results.

• 한국전기전자재료학회논문지
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• 제24권2호
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• pp.147-151
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• 2011

We were analyzed the piezoelectric characteristic for electronics printing to inkjet printing system. These applications were possible use to Actuator, MEMS, FPCB, RFID, Solar cell and LCD color filter etc. Piezoelectric print head is firing from ink droplet control consideration ink viscosity properties. At this time, micro pattern for PCB metal printing was possible by droplet control of piezoelectric driving. These driving characteristics are variable voltage pulse waveform. We are used the piezoelectric analysis software of Finite Element Method (FEM), Piezoelectric design parameters are acquired from piezoelectric analysis, and measurement of piezoelectric. It designed for piezoelectric head to possible electric print pattern of inkjet printing system. For this validity we were established through in comparison with simulation and measurement. Designed piezoelectric specification obtained voltage 98V, firing frequency 10 kHz, resolution 360dpi, drop volume 20pl, nozzle number 256, and nozzle pitch 0.33 mm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1640-1643
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• 2002

Image sticking, the phenomenon that the previously displayed pattern still remains after the image is changed into different image, is one of the most serious problem in realizing high picture quality. In this paper, we tried characterizing this undesirable feature in terms of the luminance and the intial firing voltage at ramp up time in reset period. It was found that the cell located at the boundary of previous image pattern show low firing voltage and high background luminance. And the results show that the degree of the image sticking is severely affected by discharge duration and the length of the sustain period.

• 한국세라믹학회지
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• 제24권2호
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• pp.161-169
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• 1987

An experimental study of the characteristics and the behavior of flames, and the aerodynamic flow pattern was carried out in the present work on a down draft kiln for gas firing. The aim of this work is to establish a behavior of flames and to know the extent to which the flow pattern is affected by the height of baffle plate. The measurements of temperature, concentrations of fuelgas, and kiln pressure were conducted at different temperature in kiln, and at different height of baffle plate. From the obtained results, it was found that the characteristics of thestagnation zone are greatly affected when changing over the height of baffle plate, and the best condition of that was 115m/m.

• The Korean Journal of Physiology and Pharmacology
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• 제15권3호
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• pp.163-169
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• 2011

Corticosterone is known to modulate GABAergic synaptic transmission in the hypothalamic paraventricular nucleus. However, the underlying receptor mechanisms are largely unknown. In the anterior hypothalamic area (AHA), the sympathoinhibitory center that project GABAergic neurons onto the PVN, we examined the expression of glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) of GABAergic neurons using intact GAD65-eGFP transgenic mice, and the effects of corticosterone on the burst firing using adrenalectomized transgenic mice. GR or MR immunoreactivity was detected from the subpopulations of GABAergic neurons in the AHA. The AHA GABAergic neurons expressed mRNA of GR (42%), MR (38%) or both (8%). In addition, in brain slices incubated with corticosterone together with RU486 (MR-dominant group), the proportion of neurons showing a burst firing pattern was significantly higher than those in the slices incubated with vehicle, corticosterone, or corticosterone with spironolactone (GR-dominant group; 64 vs. 11~14%, p<0.01 by $x^2$-test). Taken together, the results show that the corticosteroid receptors are expressed on the GABAergic neurons in the AHA, and can mediate the corticosteroid-induced plasticity in the firing pattern of these neurons. This study newly provides the experimental evidence for the direct glucocorticoid modulation of GABAergic neurons in the AHA in the vicinity of the PVN.

• 화약ㆍ발파
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• 제28권1호
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• pp.19-26
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• 2010

이 논문은 필리핀 석회석 광산에 적용한 연구 결과로서 이 광산에서는 파쇄석 입도분포가 좋지 않고 벽면의 유지나 파쇄석 더미의 분산이 불량하였다. 기폭패턴을 대각선 방식에서 V 타입으로 바꾸고 전색장을 조정하여 저항과 가스압의 유지기간을 향상시켰다. 이를 통하여 발파결과가 향상되었다. 특히 공당발파영역이 넓어진 것으로써 그 성과를 확인할 수 있다. 공당발파영역은 기존의 $8.96m^2$에서 $12m^2$로 넓어졌다. 화약계수는 증가하였고 대괴의 수는 감소하였으며, 전방적재기의 행정시간이 감소하였다. 또 공전 시간이 줄었으며 적재높이가 향상되었다.

• Annals of Clinical Neurophysiology
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• 제4권1호
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• pp.12-15
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• 2002

Background : Changes in firing pattern and in the recruitment order of single motor unit(MU) have been claimed to be characteristic of central motor lesions, and a reduced firing rate was found in upper motor neuron lesions. But these findings have been rarely studied before in Korea, so we studied initial MU recruitment pattern in stroke patients with hemiparesis. Methods : We studied six patients(3 men and 3 women) whose mean age was $60.6{\pm}7.4$ years. A mean $20.6{\pm}16.2$ months had elapsed since the stroke. To compare the initial MU activation patterns in proximal and distal segments of paretic limb with their contalateral unaffected counterparts, we studied the onset and recruitment intervals in biceps brachii(BB) and first dorsal interossei(FDI) muscles in paretic and healthy arms. In a single muscle we examined from 5 to 10 individual MUs. And in a single motor unit, both the onset interval and the recruitment interval was examined. Results : The mean onset interval in paretic limb was significantly(p<0.05) longer than unaffected limb at proximal and distal location: BB $118.5{\pm}17.8$ msec vs $96.1{\pm}8.3$ msec(n=58); FDI $125.8{\pm}16.7$ msec vs $101.5{\pm}17.2$ msec(n=38). The mean recruitment interval in paretic limb was also significantly(p<0.05) longer than unaffected limb: BB $87.7{\pm}14.9$ msec vs $73.4{\pm}11.5$ msec(n=53); FDI $96.3{\pm}16.4$ msec vs $87.7{\pm}14.1$ msec(n=38). Conclusion : The first recruited MU had a lower baseline firing rate and the second recruited motor unit potential appeared earlier in paretic than in healthy muscles. And these findings may explain one of the reasons for paresis in patients with stroke.