• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.121-125
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• 2003

Micromixer plays an important role in Bio-MEMS or ${\mu}-TAS$. Mixing is generally generated by turbulence and interdiffusion of two fluids. Because of low Reynolds number(Re << 2000) in ${\mu}-channel$, it is difficult to generate turbulence, so mixing mainly depends on interdiffusion. Thus long channel distance is required to mix two different fluids. To reduce the channel length required for mixing, we propose the a new active ${\mu}-mixer$ that two fluids are effectively mixed in ${\mu}-channel$ by the ultrasonic wave which is generated by PZT. The ultrasonic wave is radiated into a chamber in the cross-section directional direction to interface with the two fluids. The two fluids are positioned one on top of the other. Mixing state is measured by the changing of color due to the reaction of NaOH and phenolphtalein.

• Journal of the Korean Electrochemical Society
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• v.13 no.1
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• pp.63-69
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• 2010

Electrochemical behavior of fluoroquinolone antibacterial agents on carbon paste electrode (CPE) were investigated by cyclic voltammetry and square wave adsorptive stripping voltammetry. The fluoroquinolone antibacterial agents tested in this study were Enrofloxacin (ENR), Norfloxacin (NOR), Ciprofloxacin (CIP), Ofloxacin (OFL) and Levofloxacin (LEV). In acetate buffer at pH 4.5, the oxidation peak potentials of the fluoroquinolone antibacterial agents of ENR, NOR, CIP, OFL, and LEV were 0.952 V, 1.052 V, 1.055 V, 0.983 V, and 0.990 V (vs. Ag/AgCl), respectively. And their oxidation peak currents from square wave adsorptive stripping voltammograms are proportional to the concentration of each antibacterial agent over the range from $0.2\;{\mu}M$ to $1\;{\mu}M$.

• Korean Journal of Veterinary Research
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• v.40 no.4
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• pp.691-699
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• 2000

We investigated the effects of nitric oxide (NO) donors, S-nitroso-L-cysteine (Cys-NO) and 3-morpholinosydnonimine hydrochloride (SIN-1), on the contractile and electrical activity of the circular muscle of guinea pig gastric antrum by using intracellular microelectrode technique. The gastric antral circular muscle showed spontaneous phasic contraction and slow wave of membrane potential. Cys-NO ($0.001{\sim}10{\mu}M$) and SIN-1 ($0.001{\sim}100{\mu}M$) reduced not only the tonic and phasic contraction but also the amplitude of slow wave in a concentration dependent manner. NO donors were more potent to inhibit phasic contraction than to do slow wave. These inhibitory effects of NO donors were mimicked by the membrane permeable guanosine-3',5'-cyclic monophosphate (cGMP) analogue, 8-bromo-cyclic GMP (8-br-cGMP, $10{\sim}300{\mu}M$). The inhibitory effects of SIN-1 and Cys-NO were antagonized by the guanylate cyclase inhibitor, 1H[ [1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ, $10{\mu}M$). These results suggest that the inhibitory effects of NO donors on the mechanical and electrical activity is mainly mediated by cGMP pathway.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.1
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• pp.18-24
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• 2002

n this paper, we have fabricated pseudomorphic high electron mobility transistors (PHEMT) with a 0.2 ${\mu}{\textrm}{m}$ wide-head T-shaped gate using electron beam lithography by a dose split method. To make the T-shape gate with gate length of 0.2 ${\mu}{\textrm}{m}$ and gate head size of 1.3 ${\mu}{\textrm}{m}$ we have used triple layer resist structure of PMMA/P(MMA-MAA)/PMMA. The DC characteristics of PHEMT, which has 0.2 ${\mu}{\textrm}{m}$ of gate length, 80 ${\mu}{\textrm}{m}$ of unit gate width and 4 gate fingers, are drain current density of 323 ㎃/mm and maximum transconductance 232 mS/mm at $V_{gs}$ = -1.2V and $V_{ds}$ = 3V. The RF characteristics of the same device are 2.91㏈ of S21 gain and 11.42㏈ of MAG at 40GHz. The current gain cut-off frequency is 63GHz and maximum oscillation frequency is 150GHz, respectively.ively.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.1009-1012
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• 2000

In this paper, we have designed and fabricated power PHEMT’s with an unit gate width of 80$\mu\textrm{m}$ and 4 fingers, and MIMIC power amplifiers using the PHEMT’s as well. The PHEMT’s have a 0.2$\mu\textrm{m}$ gate length and source to drain spacing of 3$\mu\textrm{m}$. The characteristics of the fabricated PHEMT’s are 4.08dB of S$\sub$21/ gain at the 35GHz and 317mS/mm of gm, and 62GHz of f$\sub$T/ and 120GHz of f$\sub$max/. The designed and fabricated MIMIC’s power amplifiers with 6 PHEMT’s and MIN capacitors were fully passivated by 1000 Α of Si$_3$N$_4$ film for higher performance and surface protects. The chips were processed using the MINT processes, and size was 3.25 ${\times}$ 1.8$\textrm{mm}^2$. The fabricated MIMIC power amplifiers have RF characteristics such as 11.25dB of S$\sub$21/ gain, 11.37dB of input return-loss and 12.69dB of output return-loss at the 34.55GHz.

• Korean Journal of Optics and Photonics
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• v.6 no.2
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• pp.156-164
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• 1995

Based on the scalar wave equation of optical fibers, the dispersion characteristics of arbitrarily profiled fibers were analyzed. We used the I-D FEM employing quadratic interpolation fucntions to solve the scalar wave equation. We simulated the DC optical fibers as objects, and searched for the refractive index distribution to minimize the total dispersion. In DC fibers, we found the design parameters for which the total dispersion was almost zero at $\lambda=1.3{\mu}m and 1.55{\mu}m$ simultaneously. We also found the design parameters where the dispersion was flattened, less than 1.0 ps/km.nm for$\lambda=1.4~1.7{\mu}m$1. and the dispersion was as low as 0.65 ps/km.nm at $\lambda=1.55{\mu}m$..

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.765-768
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• 2005

In this paper, high LO-RF isolation 94 GHz MMIC single-balanced mixer was designed and fabricated using a branch line coupler and a ${\lambda}/4$ transmission line. The 94 GHz MMIC single-balanced mixer was designed using the 0.1 ${\mu}m$ InGaAs/InAlAs/GaAs Metamorphic HEMT(MHEMT) diode. The fabricated MHEMT was obtained the cut-off frequency($f_T$) of 189 GHz and the maximum oscillation frequency($f_{max}$) of 334 GHz. The designed MMIC single-balanced mixer was fabricated using 0.1 ${\mu}m$ MHEMT MMIC process. From the measurement, the conversion loss of the single-balanced mixer was 23.1 dB at an LO power of 10 dBm. The LO-RF isolations of single-balanced mixer was obtained 45.5 dB at 94.19 GHz. We obtained in this study a higher LO-RF isolation compared to some other balanced mixers in millimeter-wave frequencies.

• Korean Journal of Ichthyology
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• v.13 no.1
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• pp.19-23
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• 2001

The full-grown oocyte envelope of the two spined loaches, Niwaella multifasciata and Kichulchoia brevifasciata, was examined by electron microscopy. The oocyte is surrounded by its envelope, and an external modification (an adhesive structure) in the surface of the envelope is present. The envelope consists of two layers, a zona radiata externa which is the site of the adhesive structure, and a zona radiata interna, which has heterogeneous, electron-dense multi layers. The surface (zona radiata externa) of the envelope in N. multifasciata is equipped with short villuslike protuberances, which have a length of 1.5~2.5 ${\mu}m$ and are separated from each other by a distance of 2~2.5 ${\mu}m$. In contrast, K. brevifasciata has undulating or wave-like structures that extend over the entire oocyte surface. The waves are 1.5~2.5 ${\mu}m$ in length and are separated a distance of 2.5~3.3 ${\mu}m$ from each other.

• Journal of Welding and Joining
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• v.20 no.1
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• pp.76-82
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• 2002

In these days, many advanced nations have enforced import restrictions against things emitting electromagnetic wave which has report that it is so harmful. In general, electromagnetic wave is composed of electric wave and magnetic wave. The reflection of electromagnetic wave is mainly reflected by conductive materials and the magnetism loss is generated by magnetic ferrite. The magnetism loss of ferrite is separated by eddy current loss, residual magnetism loss and hysteresis loss. Thermal sprayed coating is intended to manufacture because of simple processes and high efficient electromagnetic wave shielding. The high efficient thermal sprayed coatings were made from the magnetic ferrite materials that characterizes absorption of electromagnetic wave, and the electric conductive materials that characterize emitting of electromagnetic wave. This study was manufactured thermal sprayed coatings to improve absorption-efficiency, and measured the electromagnetic wave shielding efficiency. As the experimental results, high electromagnetic wave shield efficiency was obtained at wave frequency 2GHz to thermal sprayed ferrite coatings manufactured by size distribution range of spray powders, $38~88\mu\textrm{m}$.

• Journal of Korean Medical classics
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• v.27 no.1
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• pp.47-56
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• 2014

Objective : The aim of this study is to find out the significance of Chongu pulse diagnosis as the standard of measuring the result of the acupuncture on 'the affected part of the pulse wave' based on the literature. Method : (1) The clear concepts of the 'unaffected part' and the 'affected part' were organized. (2) The relation between the pulse diagnosis and the acupuncture in Hwangjenaekyung was studied. (3) The indications of Mu acupuncture treatment(繆刺法) and Geo acupuncture treatment(巨刺法) in Hwangjenaekyung was studied. (4) The types and changes of pulse diagnosis in Hwangjenaekyung was studied, especially based on the relation between Sambuguhu pulse diagnosis(三部九候脈診) and Chongu pulse diagnosis(寸口脈診). (5) By synthesizing these results, the significance of Chongu pulse diagnosis as the standard of measuring the result of the acupuncture on 'the affected part of the pulse wave' was found. Result & Conclusion : 1. When the affected part and the unaffected part are defined, it is necessary to make clear that which one of next three definitions is used ; Firstly, 'the broad sense of definition of the affected part and the unaffected part of the symptom', which contains the pulse wave. Secondly, 'the narrow sense of definition of the affected part and the unaffected part of the symptom', without the pulse wave. And thirdly, 'the definition of the affected and the unaffected part of the pulse wave', which has the only independent standard of the pulse wave. 2. Geo acupuncture treatment(巨刺法) is an acupuncture treatment which means the needling on 'the affected part of the pulse wave' based on Sambuguhu pulse diagnosis (三部九候脈診), and Mu acupuncture treatment(繆刺法) is an acupuncture treatment which means the needling on 'the unaffected part of the symptom based on the narrow sense of the definition'. The range of the indications of Mu acupuncture treatment(繆刺法) and Geo acupuncture treatment(巨刺法) contains most of the diseases which contains Rakbyung(絡病), Kyungbyung(經病) and Ojangbyung(五臟病). 3. Chongu pulse diagnosis(寸口脈診) contains not only the range of the indications of Sambuguhu pulse diagnosis(三部九候脈診), but also most of the diseases. 4. From synthesizing these results of the study on the literature, we infer that Chongu pulse diagnosis as the standard of measuring the result of the acupuncture on 'the affected part of the pulse wave' is significant.