• The Korean Journal of Physiology
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• 제22권1호
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• pp.89-100
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• 1988

Effect of clonidine on the dorsal horn cell responses to mechanical stimulations were studies in 3 spinalized cats and 10 cats with intact spinal cord. The type of dorsal horn cells was determined according to their response patterns to four graded mechanical stimulations (brush, pressure, pinch and squeeze) applied to the respective receptive fields. In the present study the results obtained only from the wide dynamic range (WDR) cells were included. The responses of the WDR cells to noxious mechanical stimuli were selectively suppressed following intravenous administration of clonidine into the experimental animals. The clonidine-induced changes in responses of the WDR cells to mechanical stimulation were not affected by naloxone or propranolol whereas effect of clonidine on WDR cell responses was almost completely abolished after intravenous administration of yohimbine. Also in the spinalized cats results parallel to those observed in cats with intact spinal cord were obtained. The results of present study strongly implies that analgesic action of clonidine can be mediated through excitation of ${\alpha}_{2}-adrenoceptor$ even at the spinal cord level without supraspinal mechanism.

• The Korean Journal of Physiology and Pharmacology
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• 제6권5호
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• pp.241-246
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• 2002

We studied the excitatory action of morphine on the responses of dorsal horn neuron to iontophoretic application of excitatory amino acid and C-fiber stimulation by using the in vivo electrophysiological technique in the rat. In 137 of the 232 wide dynamic range (WDR) neurons tested, iontophoretic application of morphine enhanced the WDR neuron responses to N-methyl-D-aspartate (NMDA), kainate, and graded electrical stimulation of C-fibers. Morphine did not have any excitatory effects on the responses of low threshold cells. Morphine-induced excitatory effect at low ejection current was naloxone-reversible and reversed to an inhibitory action at high ejection current. NMDA receptor, calcium channel and intracellular $Ca^{2+}$ antagonists strongly antagonized the morphine-induced excitatory effect. These results suggest that changes in intracellular ionic concentration, especially $Ca^{2+},$ play an important role in the induction of excitatory effect of morphine in the rat dorsal horn neurons.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.175-175
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• 1996

The spinal dorsal horn is the area where primary afferent fibers terminate and cutaneous sensory information is Processed. A number of putative neurotransmitter substances, including excitatory and inhibitory amino acids and peptides, are present in this region and sites and cellular mechanisms of their actions have been a target of numerous studies. In this study, single neurons were acutely isolated and the properties of whole cell current and responses to excitatory and inhibitory neurotransmitters were studied by the patch clamp method. Young rats (7-14 days) were anesthetized with diethyl-ether, and the lumbar spinal cord was excised and cut transversely at a thickness of 30$\mu\textrm{m}$ by Vibroslicer. The treatment of spinal slices with low concentration of proteases (pronase and thermolysin 0.75 mg/$m\ell$) and mechanical dissociation yielded isolated neurons with near intact morphology. Multipolar, ellipsoidal and bipolar, and pyramidal cells were shown. By applying step voltage pulses to neurons held at -70 mV, two types of inward currents and one outward currents observed. The fast activating and inactivating inward current was the Na$\^$+/ current because of its fast kinetics and blocking by 0.5${\mu}$M TTX, a specific blocker of Na$\^$+/ channel. The second type of inward currents were sustained. Based on their kinetics and current-voltage relations, it was likely that the second type of inward current was the voltage-dependent Ca$\^$2+/ current. In the presence of TTX, the steady-state currents mainly represented outward K$\^$+/ current which looked like the delayed rectifier K$\^$+/ current. In addition, the membrane currents produced by agonist of excitatory amino acid (EAA) receptor and the endogenous transmitter candidate L-glutamate were recorded in isolated whole-cell voltage clamped neurons as well as responses to inhibitory amino acids (${\gamma}$-amino butyric acid, glycine). Drugs were applied by a method that allows complete exchange of the solution within 1 sec; an infinite number of solutions can be applied to a single cell.

• 전기전자학회논문지
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• 제15권4호
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• pp.299-304
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• 2011

본 논문에서는 Ka-대역에서 원형편파기, 임피던스 변환기, 직선 구조 모드변환기가 결합된 원형편파 도관관안테나를 설계 및 제작하였다. 원형 편파기는 유전체를 $45^{\circ}$ 형태로 삽입하는 형태와 타원형상의 단면을 갖는 도파관구조의 두가지 모델을 설계하여 전기적인 주요특성을 비교하였다. 또한, 직선구조 모드변환기는 계단구조의 임피던스 변환구조(stepped impedance transition)를 가지며 도파관을 진행하는 TE 모드의 전력신호를 동축선의 TEM 모드로 변환시키며, 직선모드 변환기의 입력부에 위치한 Feed-through를 통하여, 안테나를 능동모듈에 직접 연결할 수 있도록 설계하였다. 제작된 안테나는 측정결과 30.085~30.885GHz의 주파수대역에서 VSWR < 1.5, Axial ratio < 1.0dB 이하의 광대역특성을 가지며, 동일한 주파수 대역 내에서 6.7 ~ 7.0 dBi의 안테나 이득을 갖는다.

• 한국전자파학회논문지
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• 제18권4호
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• pp.430-439
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• 2007

본 논문에서는 유전자 알고리즘을 이용하여 시간 영역 측정에 사용할 광대역 TEM 혼 안테나를 개발하였다. 안테나 개발에 고려된 설계 목표로는 $2{\sim}10\;GHz$의 주파수 영역에서 -10 dB 이하(VSWR<2)의 입력단 반사 손실과, 대역폭 내에서 높은 복사 이득 그리고 낮은 이득 편차이다. 또한 TEM 혼 안테나의 전체 크기를 줄이며 휴대가 용이하도록 하기 위해 안테나 본체와 급전부를 연결할 광대역의 balun을 설계하였다. 제작된 TEM 혼 안테나의 주파수 영역 측정 결과 $2{\sim}10\;GHz$에서 -10 dB 반사 손실을 만족하며, 기존의 삼각 플레이트 형태의 TEM 혼 안테나와 비교하였을 때 그 부피가 80 % 감소하였다. 안테나의 broadside 이득 값은 $2{\sim}10\;GHz$ 대역에서 12 dBi 기준으로 이득 편차가 6 dB 이하를 만족한다. 안테나의 시간 영역 측정 결과 group delay의 변화폭은 0.4 ns 이하를 만족하며, 펄스 측정시 송신과 수신 신호의 상승 시간은 각각 58.5 ps와 66.5 ps로 대략 10 % 이내의 변화를 보였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 춘계종합학술대회
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• pp.569-571
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• 2007

본 논문에서는 Ka-대역에서 도파관 형태의 구형 혼, 원형 편파기 및 직선구조 모드변환기가 결합된 혼 안테나의 설계 및 제작에 관하여 서술한다. 원형 편파기는 광대역 특성을 가지는 유전체 타입으로 구형도파관에 $45^{\circ}$ 기울여 삽입하는 구조를 갖으며, 직선구조 모드변환기는 계단식 구조로 동축선으로부터 입력되는 TEM 모드 신호를 도파관의 TE 모드로 변환손실을 최소화 할 수 있도록 설계되었다. 제작된 혼 안테나는 $30.085\sim30.885GHz$에서 동작하며, VSWR < 1.5, Axial ratio < 1.0dB의 특성과 함께, 동작주파수 대역에서 $6.7\sim7.0dBi$의 이득을 갖는다.

• Journal of Pharmaceutical Investigation
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• 제6권3호
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• pp.4-9
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• 1976

Free amino acids in water extracts and total amino acids in hydrolystates of Deer Horn were analyzed by amino acid autoanalyzer (Technicon PNC-1 Type). The results obtained from this study are as follows ; 1) 17 kinds of amino acid, including 7 kinds of essential amino acid in human nutrition except tryptophan were identified and quantified. 2) Of all free amino acid contained in water extract, glutamic acid is the richest, and then comes Ala, Gly, Leu, Lys, valin in that order. Of all total amino acid which are closely related with nutritional valuation glycin is the richest, and then comes Glu, Lys, Ala, Leu, Ala, Pro, in that order. 3) Besides 17 kinds of amino acid, one kinds of unknown amino acid are found in water extracts and hydrolysates.

• 대한조선학회논문집
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• 제37권1호
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• pp.40-49
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• 2000

본 논문에서는 흔타를 장착한 유조선의 조타기 토오크를 초기 설계 단계에서 추정할 수 있는 경험식을 통계분석 방법을 사용하여 개발하였다. 흔타의 타단독 상태에서의 유체역학적 특성은 Molland의 수정 양력선 이론에 따라 계산하였고, 선미 와류 내의 추진기와 선체의 영향은 실적선 자료의 회귀 분석을 통하여 추정하였다. 끝으로 본 방법에 의해 얻어진 조타기 토오크 추정경험식을 실적선에 적용한 후 그 결과를 비교하였으며, 매우 유의성이 높음을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.677-681
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• 2014

A high voltage pulse generator was fabricated to radiate ultrawide band electromagnetic pulse. A coaxial type of Blumlein pulse forming line is employed to produce a pulse of high voltage (>300 kV) and short pulse duration (~5 ns). A helical strip/wire type of air-cored pulse transformer was used to charge the Blumlein pulse forming line up to more than 300 kV. A peaking switch is essential to make the pulse rise time as fast as possible. Typically, the rise time is ~500 ps. The output pulse of the generator is radiated into air through an exponentially tapered TEM horn antenna. The electric field intensity of a radiated pulse was measured as a function of the distance from the transmitting horn as well as the output voltage of the peaking switch. The peak-to-peak value of the electric field intensity at 10 m from the TEM antenna was~100 kV/m.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1348-1350
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• 1994

In this study, various nozzle of ultrasonic spray were designed by using Langevin type electrostriction transducer. The electrical and dynamic characteristics of ultrasonic nozzle with various horn type were investigated. We obtained the average particle size and size distribution profiles with output frequency.