• The Korean Journal of Physiology
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• v.22 no.1
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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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• v.6 no.5
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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.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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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.

• Journal of IKEEE
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• v.15 no.4
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• pp.299-304
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• 2011

In this paper, the circular polarized horn antenna composed of circular polarizer and impedance transformer is designed, and fabricated. For the circular polarizer, two types of the polarizer are designed and the electrical performance of them is compared; rectangular waveguide polarizer with $45^{\circ}$-inclined dielectric slab and oval shaped one. Straight type mode converter has a stepped impedance structure and plays a role of converting waveguide TE mode into coaxial TEM mode, and the proposed antenna is designed to directly connect with active components using the feed-through in the input port of the mode converter. Fabricated antenna has the wideband performance, VSWR<1.5 and Axial ratio < 1.0dB, ranging from 30.085 to 30.885 GHz, and the antenna gain is 6.7~7.0 dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.4 s.119
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• pp.430-439
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• 2007

In this paper, we propose a broadband TEM horn antenna optimized using a genetic algorithm. The characteristics required for the TEM horn are the broad matching bandwidth from 2 GHz to 10 GHz and high gain in broadside with a small gain deviation within that bandwidth. In addition, a broadband balun is designed to improve the portability and to reduce the total size of the antenna. The measured return loss of the proposed TEM horn with the broadband balun is less than -10 dB(VSWR<2) from 2 GHz to 10 GHz. Compared to a conventional triangular type TEM horn, the proposed antenna shows about 80 % reduced volume and gives the broadside gain about 12 dBi with a gain deviation less than 6 dB from 2 GHz to 10 GHz. The time domain measurement shows less than 0.4 ns group delay and the pulse measurement using the transmitting signal with the rising time of 58.5 ps shows the received pulse with the rising time of 66.5 ps, which is less than 10 % rising time variation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.569-571
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• 2007

In this paper, hem antenna composed of rectangular hern, circular polarizer and straight-type mode convertor is designed and fabricated. The circular polarizer is designed as a dielectric type having broadband characteristic, and it is inserted into the rectangular hem with $45^{\circ}$ inclination. The straight-type mode convertor has a terrace-type structure in order to convert the TEM mode signal of coaxial cable to the TE mode of rectangular waveguide, and this structure minimizes conversion loss. Fabricated hem antenna operates at $30.085\sim30.885GHz$ and has VSWR < 1.5, Axial ratio < 1.0dB and antenna gain of $6.7\sim7.0dBi$ in the band.

• Journal of Pharmaceutical Investigation
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• v.6 no.3
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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.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.1
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• pp.40-49
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• 2000

In this paper, an empirical formula to estimate the steering gear torque of a Tanker with a horn type rudder was developed by using the statistical analysis. The hydrodynamic characteristics of the horn type rudder in the free-stream condition were calculated by using the modified lifting line theory by Molland, and the interaction effects by propeller and hull were analyzed by the regression analysis of the sea-trial data of 32 vessels. The comparison with the delivered vessels' data shows that the formula can be used for predicting the steering gear torque at the initial design stage.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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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.

• Proceedings of the KIEE Conference
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• 1994.07b
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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.