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Now showing items 17 - 32 of 1087

  • 3D audio coding approach based on spatial perception features

    Yang, Cheng   Hu, Ruimin   Wang, Xiaochen   Yang, Yuhong   Zhang, Maosheng   Chen, Wei  

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  • Carbon Nanotubes Grown on Metal Microelectrodes for the Detection of Dopamine

    Yang, Cheng   Jacobs, Christopher B.   Nguyen, Michael D.   Ganesana, Mallikarjunarao   Zestos, Alexander G.   Ivanov, Ilia N.   Puretzky, Alexander   Rouleau, Christopher M.   Geohegan, David B.   Venton, B. Jill  

    Microelectrodes modified with carbon nanotubes (CNTs) are useful for the detection of neurotransmitters because the CNTs enhance sensitivity and have electrocatalytic effects. CNTs can be grown on carbon fiber microelectrodes (CFMEs) but the intrinsic electrochemical activity of carbon fibers makes evaluating the effect of CNT enhancement difficult. Metal wires are highly conductive and many metals have no intrinsic electrochemical activity for dopamine, so we investigated CNTs grown on metal wires as microelectrodes for neurotransmitter detection. In this work, we successfully grew CNTs on niobium substrates for the first time. Instead of planar metal surfaces, metal wires with a diameter of only 25 μm were used as CNT substrates; these have potential in tissue applications due to their minimal tissue damage and high spatial resolution. Scanning electron microscopy shows that aligned CNTs are grown on metal wires after chemical vapor deposition. By use of fast-scan cyclic voltammetry, CNT-coated niobium (CNT-Nb) microelectrodes exhibit higher sensitivity and lower ΔEp value compared to CNTs grown on carbon fibers or other metal wires. The limit of detection for dopamine at CNT-Nb microelectrodes is 11 ± 1 nM, which is approximately 2-fold lower than that of bare CFMEs. Adsorption processes were modeled with a Langmuir isotherm, and detection of other neurochemicals was also characterized, including ascorbic acid, 3,4-dihydroxyphenylacetic acid, serotonin, adenosine, and histamine. CNT-Nb microelectrodes were used to monitor stimulated dopamine release in anesthetized rats with high sensitivity. This study demonstrates that CNT-grown metal microelectrodes, especially CNTs grown on Nb microelectrodes, are useful for monitoring neurotransmitters.
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  • Direct and rapid quantum dots labelling of Escherichia coli cells

    Yang, Cheng   Xie, Hao   Li, Yu   Zhang, Jian-Kun   Su, Bao-Lian  

    Here, we supplied a direct and rapid quantum dots labelling method of bacterial cells in food, water and environmental contaminations. Outer layers of Escherichia coli cells prevent cells from direct interactions with molecules and objects such as quantum dots. Permeabilization treatment of E. coli cells may facilitate macromolecules penetrate cell walls and improve internal bacterial quantum dots (QDs) labelling. In this work, we investigated direct internal QDs labelling of E. coli cells permeabilized using three methods including chloroform-SDS treatment, lysozyme-EDTA treatment and osmotic shock treatment. Effects of permeabilization were analysed by scanning electronic microscopy and measuring activity of alkaline phosphatase (PhoA) released from periplasm. Internal bacterial QDs labelling was monitored by flow cytometry and fluorescent microscopy. After chloroform-SDS or lysozyme-EDTA treatment, cells could be directly labelled with QDs. No interaction was observed between osmotic shock treated cells and QDs. The mechanism of cell permeabilization explaining different labelling efficiency has been established. The QDs labelling approach presented in this work provides a simple, rapid and sensitive detection method for multiple purpose bacterial analysis in combination with biological techniques.
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  • An analysis view on password patterns of Chinese internet users

    Yang, Cheng   Hung, Jui‐long   Lin, Zhangxi  

    Purpose – In December 2011, the National Computer Network Emergency Response Technical Team/Coordination Center of China reported the most serious user data leak in history which involved 26 databases with 278 million user accounts and passwords. After acquiring the user data from this massive information leak, this study has two major research purposes: the paper aims to reveal similarities and differences of password construction among four companies; and investigate how culture factors shape user password construction in China. Design/methodology/approach – This article analyzed real-life passwords collected from four companies by comparing the following attributes: password length, password constitution, top 20 frequent passwords, character frequency distributions, string similarity, and password reuse. Findings – Major findings include that: general users in China have a weaker sense of security than those in Western countries, which reflected in the password lengths, the character combinations and the content structures; password constitution preferences are different between users in Western countries and in China, where passwords are more similar to the Pinyin context and Chinese number homonym; and password reuse is very common in China. General users tend to reuse the same passwords and IT professionals tend to engage in Seed Password reuse. Research limitations/implications – Due to the rapid growth of Internet users and e-commerce markets in China, many online service providers may not pay enough attention to security issues, but focus instead on market expansion. Employees in these companies may not be well trained in information security, resulting in carelessness when handling security issues.
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  • Sleep Apnea Detection via Depth Video & Audio Feature Learning

    Yang, Cheng   Cheung, Gene   Stankovic, Vladimir   Chan, Kevin   Ono, Nobutaka  

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  • Precision forging of alternator poles by flow control method

    Yang, Cheng   Zhao, Shengdun  

    Alternator poles have been conventionally produced by the multi-stage forging processes. As an alternative, several one-stage precision forging processes of alternator poles are put forward in this paper. The influence of different designs on metal flow and load requirements is examined through finite element simulation and experiments. It is shown that the design which has a moveable mandrel supported by a back force is useful to control the metal flow in the die cavity and to reduce the forging load. Well-shaped product can be forged successfully using a lower forging load by flow control method than that of conventional precision forging.
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  • A Novel Method of Energy Selective Surface for Adaptive HPM/EMP Protection

    Yang, Cheng   Liu, Pei-Guo   Huang, Xian-Jun  

    In this letter, a new method of energy selective surface (ESS) is presented for adaptive high-power microwave/electromagnetic pulse (HPM/EMP) protection, and a self-actuated ESS is designed with super-dense diode arrays. A prototype of size 35 times 35 cm 2 is fabricated to evaluate the performance of ESS, and an experiment under HPM radiation is carried out at 1.3 GHz. Results of measurements show that ESS has an energy low-pass characteristic of adaptive protection.
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    Yi, Bo   Dong, Yanfei   Yang, Cheng   Liu, Peiguo   Li, Yan  

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  • Evaluation of kidney allograft status using novel ultrasonic technologies

    Yang, Cheng   Hu, Mushuang   Zhu, Tongyu   He, Wanyuan  

    Abstract Early diagnosis of kidney allograft injury contributes to proper decisions regarding treatment strategy and promotes the long-term survival of both the recipients and the allografts. Although biopsy remains the gold standard, non-invasive methods of kidney allograft evaluation are required for clinical practice. Recently, novel ultrasonic technologies have been applied in the evaluation and diagnosis of kidney allograft status, including tissue elasticity quantification using acoustic radiation force impulse (ARFI) and contrast-enhanced ultrasonography (CEUS). In this review, we discuss current opinions on the application of ARFI and CEUS for evaluating kidney allograft function and their possible influencing factors, advantages and limitations. We also compare these two technologies with other non-invasive diagnostic methods, including nuclear medicine and radiology. While the role of novel non-invasive ultrasonic technologies in the assessment of kidney allografts requires further investigation, the use of such technologies remains highly promising.
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  • Epigenetics in myeloid derived suppressor cells: a sheathed sword towards cancer

    Zhang, Chao   Wang, Shuo   Liu, Yufeng   Yang, Cheng  

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  • Effects of Key Stratum Location on Hydraulic Conductivity Fracture Zone

    Yang, Cheng   Bai, Hai Bo   Rong, Hu Ren   Li, Hai Long   Wei, Xiao Qi  

    The hydraulic conductivity fracture zone is the main channel causing inrush disaster in mine. This paper makes a few analysis on the effect of the location of primary key stratum through the theoretical analysis and numerical simulation. The results show that: (1). When the distance from key stratum to coal seam is about 3 times than the height of coal seam, the hydraulic conductivity fracture zone is higher than normal but the caving zone is lower than normal. When the distance from key stratum to coal seam is about 11 times than the height of coal seam, the hydraulic conductivity fracture zone is lower than normal but the caving zone is higher than normal; (2). The effect of Winkler foundation is obvious when the distance from key stratum to coal seam is 7 times than the height of coal seam, more even but the inverse is not; (3). We can certain whether the key stratum is fractured or not according to the hypothetical rock cohesive force expediently.
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    Disclosed are a parallel-electrode welding head with a wire cutter and a method for manufacturing same. The parallel-electrode welding head comprises a welding head main body portion (101, 201), and a welding head portion (103, 203) extending from the welding head main body portion. The welding head portion comprises a welding portion (104, 204) and a wire cutter portion (105, 205), wherein the welding portion and the wire cutter portion respectively form a welding tip (104A, 204A) and a wire cutter tip (105A, 205A), and a small partition groove (107, 206) is arranged between the two tips, the plane of the wire cutter tip being slightly higher than the plane of the welding tip. When a fine enamelled wire or metal wire is welded by the welding tip, an excessive wire tail is cut off by the wire cutter portion, thereby simplifying the process of direct welding of enamelled wire.
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  • Prediction of Cutting-Direction Burr Height in Micro-Milling

    Yang, Cheng   Huang, J.   Yue, W.   Shi, G.F.   Wang, Gui Cheng  

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    Disclosed are a system and method for charging authentication in an intelligent traffic system. Said system includes: an on-board unit, which is installed on a vehicle, for performing a fee deduction transaction in a toll station, and an authentication label, which is installed on the vehicle, set to be matched with the on-board unit. Said authentication label is used to perform an authentication with the on-board unit through the wireless communication with the on-board unit. Said authentication is used to determine whether the on-board unit is matched with the authentication label, wherein, when the authentication result is that the on-board unit is matched with the authentication label, the on-board unit is allowed to continue the operation; when the authentication result is that the on-board unit is unmatched with the authentication label, the on-board unit enters an invalid state, and thus the fee deduction transaction cannot be performed. The present invention can be applied to an intelligent traffic system to prevent the on-board unit from being stolen in an electronic toll collection solution.
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  • Effect of Floating Die on Tooth Filling of Spur Gear Forging

    Yang, Cheng   Zhao, Sheng Dun  

    According to the analysis of friction distribution on radial direction in the precision forging spur gear, the reason that the tooth corner was difficult to fill is revealed. Changing the motion mode of the floating die will change the friction condition between billet and floating die, as well as the filling situation of tooth corner. Finally, the scheme was further validated by DEFORM-3D, and the results show that the validity of floating die to tooth corner filling.
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  • Product Form Design Based on Neural Network and Genetic Algorithm

    Yang, Cheng   Wu, Qun   Wu, Jian Feng  

    A method of product innovation design was presented. Based on product gene and interactive genetic algorithm, designs of products evolved into new programs, with which make customers be satisfied. In the evolutionary process, a similar model, which was made by neural network learning, was used to evaluate the fitness of products. This method not only shortened the time which was taken in the process of evolution, but also to avoid the decline in the quality of evaluations which resulted from the mental fatigue of user, and ensured the accuracy of the solution.
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