• Title/Summary/Keyword: A-type $K^+$ channel

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Development of a GIS-based Computer Program to Design Countermeasures against Debris Flows (GIS기반 토석류 산사태 대응공법 설계 프로그램 개발)

  • Song, Young-Suk;Chae, Byung-Gon
    • The Journal of Engineering Geology
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    • v.23 no.1
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    • pp.57-65
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    • 2013
  • We developed a computer program (CDFlow v. 1.0) to design countermeasures against debris flows in natural terrain. The program can predict the probability of landslides occurring in natural terrain and can estimate the zone of damage caused by a debris flow. It can also be used to design the location and size of countermeasures against the debris flow. The program is run using the ArcGIS Engine, which is one of the most well-known Geographic Information System (GIS) tools for developers. The quasi-dynamic wetness index and the infinite slope stability equation were applied to predict landslide probability as a type of slope safety factor. The calculated safety factor was compared with the required safety factor, and areas of high probable potential for landslides were then selected and represented on the digital map. The volume of debris flow was estimated using these areas of high probable potential for landslides and soil depth. The accumulated volume of debris flow can be calculated along the flow channel. To assess the accuracy of the program, it was applied to a real landslide site at Deoksan-ri, Inje-gun, Kangwon-Province, where four debris barriers have been installed in the watershed of the site. The results of soil tests and a field survey indicate that the program has great potential for estimating probable landslide areas and the trajectory of debris flows. Calculation of the capacity volume of existing debris barriers revealed that they had insufficient capacity to store the calculated amount of debris flow. Therefore, this program enables a rational estimation of the optimal location and size of debris barriers.

The Effect of Post-Bond Heat Treatment on Tensile Property of Diffusion Bonded Austenitic Alloys (확산 접합된 오스테나이트계 재료의 인장특성에 미치는 후열처리의 영향)

  • Hong, Sunghoon;Kim, Sung Hwan;Jang, Changheui;Sah, Injin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.12
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    • pp.1221-1227
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    • 2015
  • Diffusion bonding is the key manufacturing process for the micro-channel type heat exchangers. In this study, austenitic alloys such as Alloy 800HT, Alloy 690, and Alloy 600, were diffusion bonded at various temperatures and the tensile properties were measured up to $650^{\circ}C$. Tensile ductility of diffusion bonded Alloy 800HT was significantly lower than that of base metal at all test temperatures. While, for Alloy 690 and Alloy 600, tensile ductility of diffusion bonded specimens was comparable to that of base metals up to $500^{\circ}C$, above which the ductility became lower. The poor ductility of diffusion bonded specimen could have caused by the incomplete grain boundary migration and precipitates along the bond-line. Application of post-bond heat treatment (PBHT) improved the ductility close to that of base metals up to $550^{\circ}C$. Changes in tensile properties were discussed in view of the microstructure in the diffusion-bonded area.

New Sidelobe Canceller for 3-D Phased Array Radar in Strong Interference (강한 간섭 신호를 제거하기 위한 3차원 위상배열 레이다용 새로운 부엽제거기)

  • Cho, Myeong-Je;Han, Dogn-Seog;Jung, Jin-Won;Kim, Soo-Joong
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.10
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    • pp.144-155
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    • 1998
  • The array weights that will maximize the SNR for any type of noise environment are determined by the function of the antenna design configuration and the directions of receiving target and interference signals. The conventional SLCs(sidelobe cancellers) using the SNR maximization perform worst from the saturation of the receiving system of main channel when the main antenna has pattern with high gain at the arrival angle of strong interference. In this paper, the new SLC is accomplished by using two independent antenna architecture. Main antenna is implemented with adaptive nulling, which is used for rejecting high-power interference primarily. Auxiliary antenna is realized with adaptive array for receiving interference signal to be suppressed completely, which has a characteristics of sufficient gain for every direction. The new SLC is implemented with above both antennas. We show that the new SLC, which consists of the adaptive nulling main antenna and the adaptive array auxiliary antenna, is useful in reducing the effect of strong interference like jammer, because the adaptive nulling at main antenna prevents its receiver and signal processor for saturation by strong interference. The proposed SLC has improved SNR over the conventional SLCs. The improved SNR at sidelobe region is typically more than 7 dB for a given test signal. Moreover, it improves the SNR of about 20 dB under strong interference at mainlobe.

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Mass Transfer Analysis of Metal-Supported and Anode-Supported Solid Oxide Fuel Cells (금속지지체형 고체산화물연료전지와 연료극지지체형 고체산화물연료전지의 물질전달 특성분석)

  • Park, Joon-Guen;Kim, Sun-Young;Bae, Joong-Myeon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.3
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    • pp.317-324
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    • 2010
  • Metal-supported solid oxide fuel cells (SOFCs) have been developed to commercialize SOFCs. This new type of SOFC has high mechanical strength, but its mass transfer rate may be low due to the presence of a contact layer. In this study, the mass transfer characteristics of an anode-supported SOFC and a metal-supported SOFC are studied by performing numerical simulation. Governing equations, electrochemical reactions, and ceramic physical-property models are determined simultaneously; molecular diffusion and Knudsen diffusion are considered in mass transport analysis of porous media. The experimental results are compared with simulation data to validate the results of numerical simulation. The average current density of the metal-supported SOFC is 23% lower than that of the anode-supported SOFC. However, because of the presence of the contact layer, the metal-supported SOFC has a more uniform distribution than the anode-supported SOFC.

Protective Effects of Ginsenosides on Cyanide-induced Neurotoxicity in Cultured Rat Cerebellar Granule Cells

  • Seong, yeon-Hee;Koh, Sang-Bum;Jo, Soon-Ok
    • Journal of Ginseng Research
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    • v.24 no.4
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    • pp.196-201
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    • 2000
  • Effects of ginsenosides on NaCN-induced neuronal cell death were studied in cultured rat cerebellar granule cells. NaCN produced a concentration-dependent (1-10 mM) reduction of cell viability (measured by frypan blue exclusion test), that was blocked by N-methyl-D-aspartate receptor antagonist (MK-801) and L-type Ca$\^$2+/ channel blocker (verapamil). Pretreatment with ginsenosides (Rb$_1$, Rc, Re, Rf and Rg$_1$) significantly decreased the neuronal cell death in a concentration range of 0.5∼5$\mu\textrm{g}$/ml. Ginsenosides Rb$_1$ and Rc (5 $\mu\textrm{g}$/ml) inhibited glutamate release into medium induced by NaCN (5 mM). NaCN (1 mM)-induced increase of [Ca$\^$2+/], was significantly inhibited by the pretreatment of Rb$_1$ and Rc (5 $\mu\textrm{g}$/ml). Other ginsenosides caused relatively little inhibition on the elevation of glutamate release and of (Ca$\^$2+/). These results suggest that the NaCN-induced neurotoxicity was related to a series of cell responses consisting of glutamate release and [Ca$\^$2+/]i elevation via glutamate (NMDA and kainate) receptors and resultant cell death, and that ginsenosides, especially Rb$_1$ and Rc, prevented the neuronal cell death by the blockade of the NaCN-induced Ca$\^$2+/influx.

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Expression Pattern of Skeletal-Muscle Protein Genes and Cloning of Parvalbumin mRNA in Dark-banded Rockfish (Sebastes inermis) (볼락(Sebastes inermis) 근육단백질 유전자의 성장단계별 발현 양상과 parvalbumin 유전자 클로닝)

  • Jang, Yo-Soon
    • Korean Journal of Ichthyology
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    • v.23 no.1
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    • pp.1-9
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    • 2011
  • Differentially Expressed Gene (DEG) was obtained from Differential Display Reverse Transcription (DDRT)-PCR using Annealing Control Primer (ACP) to search and clone genes related to developmental stages of Sebastes inermis. By using 120 ACPs, the nucleotide sequences obtained from 16 DEGs showing higher expression in 6-month-old skeletal muscle than 18-month-old ones and from 22 DEGs displaying stronger expression in 18-month-old than 6-month-old were analyzed and BLAST was conducted. The results identified that DEGs shared 69~95% homology with genes of parvalbumin (PVALB), nucleoside diphosphate kinase (NDK) B, tropomyosin (TPM), troponin I (TnI), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), muscle-type creatine kinase (CKM2), small EDRK-rich factor 2 (SERF2), adenosine monophosphate deaminase (AMPD), Trimeric intracellular cation channel type A (TRICA), Rho GTPase-activating protein 15 (ARHGAP15), S-formylglutathione hydrolase (Esterase D; ESD), heat shock protein 70 (hsp70), type 1 collagen alpha 2 (COL1A2), glutathione S-transferase, Mid1-interacting protein 1 (Mid1lip1), myosin light chain 1 (MYL1), sarcoplasmic/endoplasmic reticulum calcium ATPase 1B (SERCA1B), and ferritin heavy subunit (FTH1). Expression pattern by developmental stage of DEG14 and PVALB exhibiting strong expression in 6-month-old skeletal muscle was investigated using real time PCR. Expression was reduced as Sebastes inermis grew. Expression of PVALB gene was extremely low after 6 months of age. Expression of CKM2 showed higher expression in 18-month-old skeletal muscle than in 6-month-old muscles, and increased continuously until 4 years old, after which CKM2 expression became gradually reduced. By analysis of tissue-specific expression patterns of DEG, DEG14 was expressed mainly in skeletal muscle, liver, kidney and spleen tissues, whereas PVALB expression was expressed in skeletal muscle and kidney, but not in liver and spleen tissues. CKM2 was expressed in skeletal muscle, kidney, and spleen tissues, but not in liver tissues. PVALB gene was composed of 110 amino acids, which constituted 659 bp nucleotides. The results reported here demonstrate that the expression patterns of parvalbumin and CKM2 could be used as molecular markers for selecting fishes exhibiting fast growth.

Conical Diffuser Design and Hydraulic Performance Characteristics in Bioreactor Using Empirical and Numerical Methods (원뿔형 산기관 설계와 생물반응조에서 수력학적 운전특성에 관한 실험 및 해석)

  • Lee, Seung-Jin;Ko, Kyeong-Han;Ko, Myeong-Han;Yang, Jae-Kyeong;Kim, Yong-Guk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.8
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    • pp.633-643
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    • 2015
  • In this study, we develop a highly efficient conical-air diffuser that generates fine bubble. By inserting a sufficient number of aerotropic microorganisms with dissolved oxygen from an air diffuser and minimizing the air-channel blockages within the air diffuser, we expect to improve the efficiency and durability of the decomposition process for organic waste. To upgrade the conventional air diffuser, we perform experiments and numerical analysis to develop a conical-type that generates fine bubble, and which is free from nozzle blockage. We complement the air-diffuser design by numerically analyzing the internal air-flow pattern within the diffuser. Then, by applying the diffuser to a mockup bioreactor, we experimentally and numerically study the bubble behavior observed in the diffuser and the 2-phase fluid flow in the bioreactor. The results obtained include statistics of the cord length and increased velocity, and we investigate the mechanisms of the fluid-flow characteristics including bubble clouds. Throughout the study, we systemize the design procedures for the design of efficient air diffusers, and we visualize the fluid-flow patterns caused by bubble generation within the mockup bioreactor. These results will provide a meaningful basis for further study as well as the detection of oxygen transfer and fluid-flow characteristics in real-scale bio-reactors using sets of air diffusers.

Accuracy evaluation of microwave water surface current meter for measurement angles in middle flow condition (전자파표면유속계의 측정 각도에 따른 평수기 유속 측정 정확도 분석)

  • Son, Geunsoo;Kim, Dongsu;Kim, Kyungdong;Kim, Jongmin
    • Journal of Korea Water Resources Association
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    • v.53 no.1
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    • pp.15-27
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    • 2020
  • Streamflow discharge as a fundamental riverine quantity plays a crucial role in water resources management, thereby requiring accurate in-situ measurement. Recent advances in instrumentations for the streamflow discharge measurement has complemented or substituted classical devices and methods. Among various potential methods, surface current meter using microwave has increasingly begun to be applied not only for flood but also normal flow discharge measurement, remotely and safely enabling practitioners to measure flow velocity postulating indirect contact. With minimized field preparedness, this method facilitated and eased flood discharge measurement in the difficult in-situ conditions such as extreme flood in active ways emitting 24.125 GHz microwave without relying on natural lights. In South Korea, a rectangular shaped instrument named with Microwave Water Surface Current Meter (MWSCM) has been developed and commercially released around 2010, in which domestic agencies charging on streamflow observation shed lights on this approach regarding it as a potential substitute. Considering this brand-new device highlighted for efficient flow measurement, however, there has been few noticeable efforts in systematic and comprehensive evaluation of its performance in various measurement and riverine conditions that lead to lack in imminent and widely spreading usages in practices. This study attempted to evaluate the MWSCM in terms of instrumen's monitoring configuration particularly regarding tilt and yaw angle. In the middle of pointing the measurement spot in a given cross-section, the observation campaign inevitably poses accuracy issues related with different tilt and yaw angles of the instrument, which can be a conventionally major source of errors for this type of instrument. Focusing on the perspective of instrument configuration, the instrument was tested in a controlled outdoor river channel located in KICT River Experiment Center with a fixed flow condition of around 1 m/s flow speed with steady flow supply, 6 m of channel width, and less than 1 m of shallow flow depth, where the detailed velocity measurements with SonTek micro-ADV was used for validation. As results, less than 15 degree in tilting angle generated much higher deviation, and higher yawing angle proportionally increased coefficient of variance. Yaw angles affected accuracy in terms of measurement area.

Omnichannel's Perception Effect on Omnichannel Use and Customer-Brand Relationship (옴니채널의 지각된 편리성과 유용성이 옴니채널 사용과 소비자-브랜드 관계에 미치는 영향)

  • Yim, Duk-Soon;Han, Sang-Seol
    • Journal of Distribution Science
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    • v.14 no.7
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    • pp.83-90
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    • 2016
  • Purpose - This study focuses on new type distribution channel that named as Omnichannel. Omnichannel is developed from Multichannel which is used in many distribution channels to buy or selling goods. Omnichannel basically needs an Information and Communications Technologies(ICT) to use, so researcher conduct a Technology Acceptance Model(TAM) to research model. Customer-brand relationship was used as dependent variable to focus on the role of Omnichannel. Research design, data, and methodology - The subject of this study is customer who purchase goods or service through omnichannel. Based on the literature from the preceding research analysis of TAM and customer-brand relationship, this study was constructed by the reference to previous studies, final research model design for figure out casual relationship among perceived ease of use, perceived usefulness, omnichannel use and customer-brand relationship. From 2016 February 3 to March 17, questionnaire survey targeted customers who use online and offline channels. 273 questionnaire survey had conducted, then, 252 survey data were available for empirical analysis. Researcher provide descriptive statistics for checking generality. Cronbach's alpha value was used to check the reliability of data. Exploratory factor analysis was used for purification of values and eigenvalue checking. After EFA, Confirmatory factor analysis was used to prepare structural equation modeling with executing structural equation modeling for confirming hypothesis which developed by researcher. Results - The main results of this empirical study are as follows. First, omnichannel's perceived ease of use has positive significant effect on perceived usefulness(estimate: 0.579). Moreover, omnichannel's perceived ease of use and perceived usefulness has positive significant effect on omnichannel use(estimate: 0.325,0.648). Second, using omnichannel has positive significant effect on brand-customer relationship(estimate: 0.521). Every hypothesis adopted as researcher designed. This study found out the intermediate relationship between perceived ease of use and omnichannel use by investigating hypothesis. Conclusions - Base on the empirical result, this study confirmed that TAM theory perceived has relation with omnichannel. First, factors of TAM has positive effect on omnichannel use, so it highlights the important role of customer based interface and usefulness. Especially, perceived usefulness has high indirect influence on ease of use and use of omnichannel. It seems that when customers try to decide use or not use omnichannel, customers focus on percept benefits from omnichannel. Thus, a provider should applicate attractive price table, accurate product or service information and high switching cost strategy to emphasize the usefulness of omnichannel. Second, using omnichannel enhances the relationship between customers and brand, because there are more time and frequency to serve customers. It is important because good relationship between customers can increase the future's financial performance through word of mouse, positive brand image and loyalty to brand or company. Finally, despite of empirical result and implications, this study has limitations. First, there are only a few previous studies about omnicahnnel, so literature reviews are restricted. While set up the factors which can affect the use of omnichannel, next study should be considered with broader theories or models(ex: contingency theory). Second, omnichannel has developed from multichannel, so comparative analysis is needed between these methods because there is a possibility about different forte character of each distribution system on customer's consuming patterns.

Adaptive Block Recovery Based on Subband Energy and DC Value in Wavelet Domain (웨이블릿 부대역의 에너지와 DC 값에 근거한 적응적 블록 복구)

  • Hyun, Seung-Hwa;Eom, Il-Kyu;Kim, Yoo-Shin
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.42 no.5 s.305
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    • pp.95-102
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    • 2005
  • When images compressed with block-based compression techniques are transmitted over a noisy channel, unexpected block losses occur. In this paper, we present a post-processing-based block recovery scheme using Haar wavelet features. No consideration of the edge-direction, when recover the lost blocks, can cause block-blurring effects. The proposed directional recovery method in this paper is effective for the strong edge because exploit the varying neighboring blocks adaptively according to the edges and the directional information in the image. First, the adaptive selection of neighbor blocks is performed based on the energy of wavelet subbands (EWS) and difference of DC values (DDC). The lost blocks are recovered by the linear interpolation in the spatial domain using selected blocks. The method using only EWS performs well for horizontal and vertical edges, but not as well for diagonal edges. Conversely, only using DDC performs well diagonal edges with the exception of line- or roof-type edge profiles. Therefore, we combined EWS and DDC for better results. The proposed methods out performed the previous methods using fixed blocks.