• Title/Summary/Keyword: channel properties

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[${^3H}Ryanodine$ Binding Sites of SR Vesicles of the Chicken Pectoral Muscle

  • Yun, Hyo-Yung;Jeon, Jong-Rye;Hong, Jang-Hee;Hur, Gang-Min;Lee, Jae-Heun;Seok, Jeong-Ho
    • The Korean Journal of Physiology and Pharmacology
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    • v.1 no.4
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    • pp.377-384
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    • 1997
  • To investigate the properties of ryanodine binding sites of the bird skeletal SR vesicles, SDS PAGE, purification of RyR, and $[^3H]ryanodine$ binding study were carried out in the SR vesicles prepared from the chicken pectoral muscle. The chicken SR vesicles have two high molecular weight (HMW) protein bands as in eel SR vesicles on SDS PAGE. The HMW bands on SDS PAGE were found in the $[^3H]ryanodine$ peak fraction $(Fr_{3-5})$ obtained from the purification step of the ryanodine receptor protein. Bmax and KD of the chicken $[^3H]ryanodine$ binding sites were 12.52 pmol/mg protein and 14.53 nM, respectively. Specific $[^3H]ryanodine$ binding was almost maximal at $50{\sim}100$ ${\mu}M$ $Ca^{2+}$, but was not increased by 5 mM AMP and not inhibited by high $Ca^{2+}$. Binding was significantly inhibited by $20{\sim}100$ ${\mu}M$ ruthenium red and 1 mM tetracaine, but slightly inhibited by $Mg^{2+}$. From the above results, it is suggested that chicken SR vesicles have the ryanodine binding sites to which the binding of ryanodine is almost maximal at $50{\sim}10$ ${\mu}M$ $Ca^{2+}$, is significantly inhibited by ruthenium red and tetracaine, slightly inhibited by $Mg^{2+}$, but not affected by AMP and not inhibited by high $Ca^{2+}$.

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Effects of α1-adrenoceptor stimulation on ventricular electrophysiological properties of guinea pigs (기니픽 심근의 전기생리학적 특성에 미치는 α1-Adrenoceptor 자극효과)

  • Kim, Jin-sang
    • Korean Journal of Veterinary Research
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    • v.33 no.2
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    • pp.199-209
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    • 1993
  • The effects of ${\alpha}_1$-adrenergic stimulation on membrane potential, intracellular sodium activity $(a_N{^i{_a}})$, and contractility were investigated in the isolated papillary muscle of euthyroid, hyperthyroid, and hypothyroid guinea pigs. Cardiac alterations in the thyroid state have been shown to induce marked changes in action potential characteristics, the most pronounced shortening of action potential duration by hyperthyroidism and an increase in duration by hypothyroidism. $10^{-5}M$ Phenylephrine produced a decrease in $(a_N{^i{_a}})$ in euthyroid and hypothyroid preparations, but an increase in $(a_N{^i{_a}})$ in hyperthyroid ones. The major findings were that phenylephrine produced a stronger positive inotropic effect(PIE) without initial negative inotropic effect(NIE) in hyperthyroid preparations, while phenylephrine produced markedly NIE in hypothyroid ones. The alterations in membrane potential, $(a_N{^i{_a}})$, and contractility were abolished by $3{\times}10^{-5}M$ prazosin in hypothyroidism. In hypothyroid ventricular muscle, the decrease in $(a_N{^i{_a}})$ caused by phenylephrine were not abolished or reduced by $10^{-5}M$ strophanthidin, $10^{-5}M$ TTX, $3{\times}10^{-4}M$ lidocaine, or $100^{-5}M$ verapamil. These results indicate that the ${\alpha}_1$-adrenoceptor-mediated decrease in $(a_N{^i{_a}})$ is not associated with a stimulation of the $Na^+$-$K^+$ pump, inhibition of the $Na^+$ or $Ca^+$ channel in hypothyroid ventricular muscle. $10^{-5}M$ Phenylephrine decreased $(a_N{^i{_a}})$ but increased $(a_N{^i{_a}})$ in the presence of a PKC activator phorbol dibutyrate$(PDB_u)$. In conclusion, it is suggested that the following sequence of events in response to phenyleplhane occur in guinea pig ventricular muscle. First, changes in thyroid state may contribute to the ventacular electrophysiological propeties or ion transport system. Second, the adrenoceptor-mediated initial transient NIE may be associated with the decrease in $(a_N{^i{_a}})$ by PKC activation.

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Influence of Oxygen Partial Pressure on ZnO Thin Films for Thin Film Transistors

  • Kim, Jae-Won;Kim, Ji-Hong;Roh, Ji-Hyoung;Lee, Kyung-Joo;Moon, Sung-Joon;Do, Kang-Min;Park, Jae-Ho;Jo, Seul-Ki;Shin, Ju-Hong;Yer, In-Hyung;Koo, Sang-Mo;Moon, Byung-Moo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.106-106
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    • 2011
  • Recently, zinc oxide (ZnO) thin films have attracted great attention as a promising candidate for various electronic applications such as transparent electrodes, thin film transistors, and optoelectronic devices. ZnO thin films have a wide band gap energy of 3.37 eV and transparency in visible region. Moreover, ZnO thin films can be deposited in a poly-crystalline form even at room temperature, extending the choice of substrates including even plastics. Therefore, it is possible to realize thin film transistors by using ZnO thin films as the active channel layer. In this work, we investigated influence of oxygen partial pressure on ZnO thin films and fabricated ZnO-based thin film transistors. ZnO thin films were deposited on glass substrates by using a pulsed laser deposition technique in various oxygen partial pressures from 20 to 100 mTorr at room temperature. X-ray diffraction (XRD), transmission line method (TLM), and UV-Vis spectroscopy were employed to study the structural, electrical, and optical properties of the ZnO thin films. As a result, 80 mTorr was optimal condition for active layer of thin film transistors, since the active layer of thin film transistors needs high resistivity to achieve low off-current and high on-off ratio. The fabricated ZnO-based thin film transistors operated in the enhancement mode with high field effect mobility and low threshold voltage.

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A Rapid Convergent Max-SINR Algorithm for Interference Alignment Based on Principle Direction Search

  • Wu, Zhilu;Jiang, Lihui;Ren, Guanghui;Wang, Gangyi;Zhao, Nan;Zhao, Yaqin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.5
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    • pp.1768-1789
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    • 2015
  • The maximal signal-to-interference-plus-noise ratio (Max-SINR) algorithm for interference alignment (IA) has received considerable attention for its high sum rate achievement in the multiple-input multiple-output (MIMO) interference channel. However, its complexity may increase dramatically when the number of users approaches the IA feasibility bound, and the number of iterations and computational time may become unacceptable. In this paper, we study the properties of the Max-SINR algorithm thoroughly by presenting theoretical insight into the algorithm and by providing the potential of reducing the overall computational cost. Furthermore, a novel IA algorithm based on the principle direction search is proposed, which can converge more rapidly than the conventional Max-SINR method. In the proposed algorithm, it searches along the principle direction, which is found to approximately point to the convergence values, and can approach the convergence solutions rapidly. In addition, the closed-form solution of the optimal step size can be formulated in the sense of minimal interference leakage. Simulation results demonstrate that the proposed algorithm outperforms the conventional minimal interference leakage and Max-SINR algorithms in terms of the convergence rate while guaranteeing the high throughput of IA networks.

a-C:H Films Deposited in the Plasma of Surface Spark Discharge at Atmospheric Pressure. Part I: Experimental Investigation

  • Chun, Hui-Gon;K.V. Oskomov;N.S. Sochungov;Lee, Jing-Hyuk;You, Yong-Zoo
    • Journal of the Korean institute of surface engineering
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    • v.36 no.5
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    • pp.357-363
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    • 2003
  • The aim of this work is the synthesis of a-C:H films from methane gas using surface spark discharge at the atmospheric pressure. Properties of these films have been investigated as functions of energy W delivered per a methane molecule in the discharge. The method enables the coatings to be deposited with high growth rates (up to $100 \mu\textrm{m}$/hour) onto large-area substrates. It is shown that the films consist of spherical granules with diameter of 20∼50 nm formed in the spark channel and then deposited onto the substrate. The best film characteristics such as minimum hydrogen-to-carbon atoms ratio H/C=0.69, maximum hardness $H_{v}$ =3 ㎬, the most dense packing of the granules and highest scratch resistance has been obtained under the condition of highest energy W of 40 eV. The deposited a-C:H coatings were found to be more soft and hydrogenated compared to the diamond-like hydrogenated (a-C:H) films which obtained by traditional plasmaenhanced chemical vapor deposition methods at low pressure (<10 Torr). Nevertheless, these coatings can be potentially used for scratch protection of soft plastic materials since they are of an order harder than plastics but still transparent (the absorption coefficient is about $10^4$$10^{5}$ $m^{-1}$ At the same time the proposed method for fast deposition of a-C:H films makes this process less expensive compared to the conventional techniques. This advantage can widen the application field of. these films substantially.y.

A Study on Improving the Correlation Characteristics of a Ternary Sequence (삼치 시퀀스의 상관함수 특성 개선 연구)

  • 권성재
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • 2002.11a
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    • pp.407-411
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    • 2002
  • Ternary sequences are digital codes consisting of discrete values -1, 0, and 1 only. They are advantageous in that the correlation can be carried out using additions only Also, they feature an ideal circular autocorrelation function, but in channel characterization tasks, the usual requirement is that the linear autocorrelation function be ideal, i.e., a Kronecker delta function. In this article, we consider two approaches to improving their linear autocorrelation or crosscorrelation properties: one is an inverse filtering method with theresholding and the other is a singular value decomposition (SVD) method. Both methods are simulated under noisy circumstances. The inverse filtering method resulted in an improvement in peak sidelobe level of about 1㏈ at an SNR of 30㏈, and the SVD method showed similar performances, albeit more sensitive to noise depending on the singular value selection strategy.

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Code Rate 1/2, 2304-b LDPC Decoder for IEEE 802.16e WiMAX (IEEE 802.16e WiMAX용 부호율 1/2, 2304-비트 LDPC 복호기)

  • Kim, Hae-Ju;Shin, Kyung-Wook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.4A
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    • pp.414-422
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    • 2011
  • This paper describes a design of low-density parity-check(LDPC) decoder supporting block length 2,304-bit and code rate 1/2 of IEEE 802.16e mobile WiMAX standard. The designed LDPC decoder employs the min-sum algorithm and partially parallel layered-decoding architecture which processes a sub-matrix of $96{\times}96$ in parallel. By exploiting the properties of the min-sum algorithm, a new memory reduction technique is proposed, which reduces check node memory by 46% compared to conventional method. Functional verification results show that it has average bit-error-rate(BER) of $4.34{\times}10^{-5}$ for AWGN channel with Fb/No=2.1dB. Our LDPC decoder synthesized with a $0.18{\mu}m$ CMOS cell library has 174,181 gates and 52,992 bits memory, and the estimated throughput is about 417 Mbps at 100-MHz@l.8-V.

Color Analysis and Binarization of River Image for River Surveillance (하천 감시를 위한 하천 영상의 색상 분석 및 이진화 방법)

  • Park, Sang-Hyun
    • The Journal of the Korea institute of electronic communication sciences
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    • v.13 no.1
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    • pp.175-186
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    • 2018
  • Due to global warming, various natural disasters such as floods and localized heavy rains are increasing. If a natural disaster can be detected and analyzed in advance and effectively, it can prevent enormous damage due to natural disasters. Recent development in visual sensor technologies has encouraged various studies on monitoring environments including rivers. In this paper, we propose a method to detect river regions from river images which can be exploited for river surveillance systems using video sensor networks. In the proposed method, we first analyze the color properties of the river region and the background region of a image and then propose a way to select the proper color channel and binarize the image to detect the river region. It is shown by experimental results that the proposed method is simple but detects river regions accurately.

Improvement in the negative bias stability on the water vapor permeation barriers on Hf doped $SnO_x$ thin film transistors

  • Han, Dong-Seok;Mun, Dae-Yong;Park, Jae-Hyeong;Gang, Yu-Jin;Yun, Don-Gyu;Sin, So-Ra;Park, Jong-Wan
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2012.05a
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    • pp.110.1-110.1
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    • 2012
  • Recently, advances in ZnO based oxide semiconductor materials have accelerated the development of thin-film transistors (TFTs), which are the building blocks for active matrix flat-panel displays including liquid crystal displays (LCD) and organic light-emitting diodes (OLED). However, the electrical performances of oxide semiconductors are significantly affected by interactions with the ambient atmosphere. Jeong et al. reported that the channel of the IGZO-TFT is very sensitive to water vapor adsorption. Thus, water vapor passivation layers are necessary for long-term current stability in the operation of the oxide-based TFTs. In the present work, $Al_2O_3$ and $TiO_2$ thin films were deposited on poly ether sulfon (PES) and $SnO_x$-based TFTs by electron cyclotron resonance atomic layer deposition (ECR-ALD). And enhancing the WVTR (water vapor transmission rate) characteristics, barrier layer structure was modified to $Al_2O_3/TiO_2$ layered structure. For example, $Al_2O_3$, $TiO_2$ single layer, $Al_2O_3/TiO_2$ double layer and $Al_2O_3/TiO_2/Al_2O_3/TiO_2$ multilayer were studied for enhancement of water vapor barrier properties. After thin film water vapor barrier deposited on PES substrate and $SnO_x$-based TFT, thin film permeation characteristics were three orders of magnitude smaller than that without water vapor barrier layer of PES substrate, stability of $SnO_x$-based TFT devices were significantly improved. Therefore, the results indicate that $Al_2O_3/TiO_2$ water vapor barrier layers are highly proper for use as a passivation layer in $SnO_x$-based TFT devices.

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A Molecular Dynamics Study of the Stress Effect on Oxidation Behavior of Silicon Nanowires

  • Kim, Byeong-Hyeon;Kim, Gyu-Bong;Park, Mi-Na;Ma, U-Ru-Di;Lee, Gwang-Ryeol;Jeong, Yong-Jae
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.499-499
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    • 2011
  • Silicon nanowires (Si NWs) have been extensively studied for nanoelectronics owing to their unique optical and electrical properties different from those of bulk silicon. For the development of Si NW devices, better understanding of oxidation behavior in Si NWs would be an important issue. For example, it is widely known that atomic scale roughness at the dielectric (SiOx)/channel (Si) interface can significantly affect the device performance in the nano-scale devices. However, the oxidation process at the atomic-scale is still unknown because of its complexity. In the present work, we investigated the oxidation behavior of Si NW in atomic scale by simulating the dry oxidation process using a reactive molecular dynamics simulation technique. We focused on the residual stress evolution during oxidation to understand the stress effect on oxidation behavior of Si NWs having two different diameters, 5 nm and 10 nm. We calculated the charge distribution according to the oxidation time for 5 and 10 nm Si NWs. Judging from this data, it was observed that the surface oxide layer started to form before it is fully oxidized, i.e., the active diffusion of oxygen in the surface oxide layer. However, it is well-known that the oxide layer formation on the Si NWs results in a compressive stress on the surface which may retard the oxygen diffusion. We focused on the stress evolution of Si NWs during the oxidation process. Since the surface oxidation results in the volume expansion of the outer shell, it shows a compressive stress along the oxide layer. Interestingly, the stress for the 10 nm Si NW exhibits larger compressive stress than that of 5 nm Si NW. The difference of stress level between 5 an 10 anm Si NWs is approximately 1 or 2 GPa. Consequently, the diameter of Si NWs could be a significant factor to determine the self-limiting oxidation behavior of Si NWs when the diameter was very small.

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