• The Korean Journal of Physiology and Pharmacology
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• 제24권6호
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• pp.529-543
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• 2020

In contrast to ventricular myocytes, the structural and functional importance of atrial transverse tubules (T-tubules) is not fully understood. Therefore, we investigated the ultrastructure of T-tubules of living rat atrial myocytes in comparison with ventricular myocytes. Nanoscale cell surface imaging by scanning ion conductance microscopy (SICM) was accompanied by confocal imaging of intracellular T-tubule network, and the effect of removal of T-tubules on atrial excitation-contraction coupling (EC-coupling) was observed. By SICM imaging, we classified atrial cell surface into 4 subtypes. About 38% of atrial myocytes had smooth cell surface with no clear T-tubule openings and intracellular T-tubules (smooth-type). In 33% of cells, we found a novel membrane nanostructure running in the direction of cell length and named it 'longitudinal fissures' (LFs-type). Interestingly, T-tubule openings were often found inside the LFs. About 17% of atrial cells resembled ventricular myocytes, but they had smaller T-tubule openings and a lower Z-groove ratio than the ventricle (ventricular-type). The remaining 12% of cells showed a mixed structure of each subtype (mixed-type). The LFs-, ventricular-, and mixed-type had an appreciable amount of reticular form of intracellular T-tubules. Formamide-induced detubulation effectively removed atrial T-tubules, which was confirmed by both confocal images and decreased cell capacitance. However, the LFs remained intact after detubulation. Detubulation reduced action potential duration and L-type Ca²⁺ channel (LTCC) density, and prolonged relaxation time of the myocytes. Taken together, we observed heterogeneity of rat atrial T-tubules and membranous ultrastructure, and the alteration of atrial EC-coupling by disruption of T-tubules.

• 한국진공학회지
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• 제15권6호
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• pp.587-593
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• 2006

외부전극 형광램프를 광원으로 하는 백라이트의 저항$(R_L)$과 전기용량(C), 그리고 인버터의 트랜스포머 인덕턴스(L)로 구성된 회로를 분석하였다. 램프의 저항과 전기용량은 램프에 흐르는 전류와 전압의 위상차 및 Q-V 그래프에서 결정된다. 32인치용 EEFL 램프 하나의 저항 값은 $66\;k\Omega$이고 전기용량은 21.61 pF이다. 20 개의 EEFL을 병렬 연결한 백라이트의 저항은 $3.3\;k\Omega$이고 전기용량은 402.1 pF이다. 램프 및 트랜스포머 회로에서 임피던스 매칭 주파수는 2 차 코일의 인덕턴스 $L_2$와 결합계수 k로 나타내며, $\omega_M=1/\sqrt{L_2C(1-k^2)}$ 이다. 램프 시스템의 전류와 전압은 임피던스 매칭 주파수에서 최대값을 갖는다. 이러한 해석 해의 결과는 실험 결과와 잘 일치한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.863-866
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• 1998

In this paper two quick boosting charge pump circuits for high-speed EEPROM memory are proposed. In order to improve initial charge transfer efficiency, one uses weighted capacitors where each stage has different clock coupling capacitance, and the other uses a multi-path structure at the first stage. SPICE simulation results show that these charge pumps have improve drising-time characteristics, but their $V_{DD}$ mean currents are increased a little compared with conventioanl charge pumps. The rising time upt o 15V of the proposed charge pumps is 3 times faster than that of dickson's pump at the cost of 1.5 tiems more $V_{DD}$ mean current.rrent.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.844-846
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• 2008

A new p-type conjugated copolymer, poly(9,10-diethynylanthracene-alt-9,9-didodecylfluorene (PDADF) was synthesized through a Sonogashira coupling reaction. A solution-processed thin film transistor device showed a carrier mobility value of $6.0\;{\times}\;10^{-4}\;cm^2/Vs$ with a threshold voltage of -17 V and a capacitance ($C_i$) of $10\;nF/cm^2$.

• 전자공학회논문지D
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• 제34D권5호
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• pp.14-21
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• 1997

The crosstalk among three identical uniform coupled microstrip transmissiom lines is examined. To analyze the crosstalk, the simultaneous equations for the voltage and current waves on each transmission line are induced from the transmission line equation. The capacitance and the inductance of the line to solve the transmission line equation are calculated by the spectral domain analysis and the space domian analysis. There are three quasi-TEM modes is three microstrip transmission lines and the characteristics mode impedences in each mode are almost equal at a weak coupling state. The crosstalk among three identical microstrip transmission lines is calculated varying the frequency from 50MHz to 3GHz.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2004년도 추계학술대회 학술발표 논문집 제14권 제2호
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• pp.515-520
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• 2004

In this paper, a passive telemetry RF capacitive humidity sensor system using a RLSE(Recursive Least Square Estimation) technique is proposed. To overcome these trouble problems such as a power limitation and a estimation complexity that the general passive telemetry sensor system including It chip has, the principle of inductive coupling was applied to the modeling of a passive telemetry RF capacitive humidity sensor system and its capacitance was estimatedd by the RLSE algorithm. Specially, by introducing the optimal forgetting factor, we showed that the accuracy of its estimation was improved even in the time varying system and also the convergence time was reduced.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.305-308
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• 2009

This paper presents the design and analysis of RF Front End for Wireless Heartbeat measurement System. In this work LNA, an inductor connected at the gate of the cascode transistor and capacitive cross-coupling are strategically combined to reduce the noise and the nonlinearity influences of the cascode transistors in a differential LNA. The Mixer is implemented by using the Gilbert-type configuration, cross pmos injection technique and the resonating technique for the tail capacitance. The resulting LNA achieves 1.26 dB NF, better than 1.88dB NF Typical Also Mixer resulting achieves 9.8dB at 100KHz.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.188-192
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• 2003

A multilayer two-stage LC bandpass filter using low-temperature cofired-ceramic (LTCC) is proposed in this paper. The proposed bandpass filter is composed of two ceramic substrates with different dielectric constant instead of single ceramic material from top to bottom layer. The bandpass filter size is $2.0 mm{\times}1.2 mm{\times}0.8 mm$. Positioning of attenuation polefrequency, importance parameter for a performance of filter, is discussed using even-odd mode analysis by tuned capacitance of coupling capacitor and those results is implemented to LTCC filter circuit. Measured filter performances show that the insertion losses are -4.5dB, -4.1dB at 2.45GHz, 2.75GHz and the return losses are -8.5dB, 8.7dB.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1406-1407
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• 2008

In this paper, a micro balanced filter in magnetically coupled LC resonators is proposed, designed, simulated by using FR-4 PCB substrate for low cost, small volume IEEE 802. 11a wireless LAN application. Two pair of coupled LC resonators using magnetic coupling of embedded inductors are applied to obtain bandpass transmission response and improve their phase and magnitude imbalance characteristics. In addition, high dielectric composite film is applied to fabricate the high Q MIM capacitors with small size and high capacitance density. It has an insertion loss of 1.4 dB, a return loss of 10 dB, a phase imbalance of 0.25 degree, and magnitude imbalance of 0.17 dB at frequency bandwidth of 200 MHz ranged from 5.15 GHz to 5.35 GHz, respectively. The proposed balanced filter has a small volume of $1.1mm{\times}1.3mm{\times}0.6mm$ (height).

• The Journal of the Acoustical Society of Korea
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• 제13권1E호
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• pp.5-10
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• 1994

삼층 기판위의 삼중 결합 마이크로스트립 서로의 해석을 위한 수치해석의 일반식이 얻어졌다. 유한차분식을 얻기 위한 방법과 특이점 처리를 위한 최적의 방법이 구해졌다. 홀수 모드와 짝수 모드의 캐패시턴스와 특성 임피이던스의 수치해석 결과를 보였으며 그 결과들은 이층의 두께와 삼층의 마치크로스트립 폭의 비에 따라 구해졌다. 수치해석으로 구한 짝수 모드 캐패시턴스는 다른 수치해석 결과와 비교되었다.