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Now showing items 65 - 80 of 1618

  • Using the loci framework for automated program and component generation

    Yang Zhang   Edward A. Luke  

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  • An Extremely Linear Multi-level DAC for Continuous-time Delta-Sigma Modulators

    Yang Zhang   He Xiaoyong   Pun Kong-Pang  

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  • Observations of the initial stage of a rocket‐and‐wire‐triggered lightning discharge

    Yang Zhang   Paul R. Krehbiel   Yijun Zhang   Weitao Lu   Dong Zheng   Liangtao Xu   Zhigang Huang  

    Observations have been obtained of the initial stage of a rocket-and-wire-triggered lightning flash with a high-resolution broadband VHF interferometer. The discharge produced 54 precursor current pulses (PCPs) over 883 ms during the rocket's ascent. The interferometer observations show that the PCPs were produced by breakdown at the ascending tip of the rocket, and that individual PCPs were produced by weak upward positive breakdown over meters-scale distances, followed by more energetic, fast downward negative breakdown over several tens of meters distance. The average propagation speeds were ~5 × 106 m s−1 and ~3 × 107 m s−1, respectively. The sustained upward positive leader (UPL) was initiated by a rapid, repetitive burst of 14 precursor pulses. Upon initiation, the VHF radiation abruptly became continuous with time. Significantly, breakdown during the UPL appeared to extend the discharge in a similar manner to that of the precursor pulses.
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  • Germline cytotoxic lymphocytes defective mutations in Chinese patients with lymphoma

    Xue Chen   Yang Zhang   Fang Wang   Mangju Wang   Wen Teng   Yuehui Lin   Xiangping Han   Fangyuan Jin   Yuanli Xu   Panxiang Cao   Jiancheng Fang   Ping Zhu   Chunrong Tong   Hongxing Liu  

    Certain patients with lymphoma may harbor mutations in perforin 1 (PRF1), unc-13 homolog D (UNC13D), syntaxin 11 (STX11), STXBP2 (syntaxin binding protein 2) or SH2 domain containing 1A (SH2D1A), which causes functional defects of cytotoxic lymphocytes. Data regarding the association between genetic defects and the development of lymphoma in Chinese patients are limited to date. In the present study, 90 patients with lymphoma were analyzed for UNC13D, PRF1, STXBP2, STX11, SH2D1A and X-linked inhibitor of apoptosis. Mutations were observed in 24 (26.67%) patients; 16 patients exhibited mutations in UNC13D, 7 exhibited PRF1 mutations, and 1 exhibited monoallelic mutation in STX11. UNC13D c.2588G>A/p.G863D mutation was detected in 9 patients (10.00%) and in 4/210 controls (1.90%). This mutation was predicted to be pathogenic and it predominantly existed in the Chinese population. These findings suggest that impaired cytotoxic machinery may represent a predisposing factor for the development of lymphoma. Furthermore, these data describe a distinct mutation spectrum in Chinese patients with lymphoma, whereby UNC13D is the most frequently mutated gene. In addition, these findings suggest UNC13D c.2588G>A mutation is a founder mutation in Chinese patients.
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  • Carbon Emissions from Forest Fires in Great Xing’an Mountains from 1980 to 2005

    Yang Zhang   Hai-qing Hu   Qiang Wang  

    A combination of federal inventory data and ground-based approach was used to compute the amount of carbon released by forest fires in Great Xing’an Mountains from 1980 to 2005. Base on the field survey data and allometric equations, biomass of 32 separate carbon pools in 8 forest types were estimated. Combustion factors were then calculated from these survey data. An improved estimation method was used and then got the total pyrogenic carbon emissions. About 12061232.48 t carbon was released by forest fires during 1980-2005.
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  • Decomposition of chromite ore by oxygen in molten NaOH–NaNO3

    Yang Zhang   Shi-li Zheng   Hong-bin Xu   Hao Du   Yi Zhang  

    An optimized process production of chromate by oxygen was proposed. The tests are executed by introducing NaNO3 to the decomposition process of chromite ore in molten NaOH to decrease the decomposition temperature. An interesting result is that the reaction temperature could decrease from above 500 °C to about 400 °C, and sodium nitrate has no consumption in the oxidation process, while the Cr yield is above 99%. Mechanism analysis shows that chromite ore is firstly oxidized by NaNO3, where NaNO2 is generated as a reduction product, and then is oxidized to NaNO3. NaNO3 plays the role of oxygen carrier, which can reduce the mass transfer resistance of oxygen. The kinetic study shows that the decomposition process was an internal diffusion controlled, with an apparent activation energy of 106 kJ/mol. Effects of liquid-to-ore ratio, chromite ore particle size, and reaction temperature on the decomposition of chromite ore were also studied.
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  • Systems, methods, and apparatuses for erasing memory on wireless devices

    A wireless device having a memory is provided. The memory or a protected portion of the memory is subject to a hard erasure of the memory vs. a soft erasure of the memory if a plurality of sensors indicate a threat to the device exists. The threat may be detected by a plurality of sensors, such as, a timer, a connectivity sensor, a location sensor or geo-fence, a breech sensor, an authentication procedure or the like.
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  • Kernel Based K-Medoids for Clustering Data with Uncertainty

    Baoguo Yang   Yang Zhang  

    Uncertain data is ubiquitous in real-world applications due to various causes. In recent years, clustering uncertain data has been paid more attention by the research community, and the classical clustering algorithms based on partition, density and hierarchy have been extended to handle the uncertain data. However, these extended algorithms usually work in the input space. In this paper, to well explore the inherent data pattern in the high dimensional feature space, we propose a kernel based K-medoids algorithm for clustering uncertain data. Extensive experiments performed on synthetic and several real datasets demonstrate that our kernel based method has higher clustering accuracy than the state-of-the-art UK-medoids algorithm. Also, it signifies that the uncertain data pattern in the new feature space could be well presented when the kernel function and the K-medoids algorithm are effectively incorporated.
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  • Outlier Detection Techniques for Wireless Sensor Networks: A Survey

    Yang Zhang   Meratnia, N.   Havinga, P.  

    In the field of wireless sensor networks, those measurements that significantly deviate from the normal pattern of sensed data are considered as outliers. The potential sources of outliers include noise and errors, events, and malicious attacks on the network. Traditional outlier detection techniques are not directly applicable to wireless sensor networks due to the nature of sensor data and specific requirements and limitations of the wireless sensor networks. This survey provides a comprehensive overview of existing outlier detection techniques specifically developed for the wireless sensor networks. Additionally, it presents a technique-based taxonomy and a comparative table to be used as a guideline to select a technique suitable for the application at hand based on characteristics such as data type, outlier type, outlier identity, and outlier degree.
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  • Synthesis and characterization of energetic GAP-b-PAEMA block copolymer

    Yang Zhang   Juan Zhao   Pan Yang   Shangjin He   Hengjian Huang  

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  • Methods and apparatus for non-invasive implantable pressure sensor calibration

    An economical, repeatable, and non-invasive method and apparatus for the calibration of implantable pressure sensors that can minimize patient discomfort and risk of infection. In one embodiment, a calibration system for calibrating a first pressure sensor coupled to a management device and implanted into a human patient is provided. The calibration system includes a mouthpiece, a pump, a second pressure sensor, and a computer. The pump provides a positive pressure into an airway of the human patient via the mouthpiece. The second pressure sensor measures the airway pressure of the human patient, and the computer is coupled to the pump and monitors pressures measured by the first and second pressure sensors. Here, the computer also calculates one or more calibration constants based on the pressures measured by the first and second pressure sensors and provides the calibration constants to the management device to calibrate the first pressure sensor.
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  • Extending the Theory of Green Retailing: Green Facility Utilization

    Yang Zhang  

    Green or environmental sustainability has currently gained increasing attention in retail sector. It is important for the practitioners to have a clear understanding and comprehensive overview of relevant environmental initiatives. The existing framework of green retailing only included store and transport as two sub-strategies of the internal dimension. However, based on a case study method, the study finds that companies carry out environmental project not only in their stores, but also in offices and warehouses/DC. This article thus complements the existing framework by including these two facilities. Besides, this paper further investigates the practical measures that currently taken by sample retailers to manage environmental issues in their facilities with a framework of green facility strategy being formed. The finding shows that that retailers ènvironmental initiatives mainly focus on three aspects: energy, waste and water, and the future trend is towards green building design and construction. Another trend worth noticing is that renewable energy has become popular among companies. In addition, retailer has integrated waste management with energy project, seeking to turn waste into energy.
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  • Extending the Theory of Green Retailing: Green Facility Utilization

    Yang Zhang  

    Green or environmental sustainability has currently gained increasing attention in retail sector. It is important for the practitioners to have a clear understanding and comprehensive overview of relevant environmental initiatives. The existing framework of green retailing only included store and transport as two sub-strategies of the internal dimension. However, based on a case study method, the study finds that companies carry out environmental project not only in their stores, but also in offices and warehouses/DC. This article thus complements the existing framework by including these two facilities. Besides, this paper further investigates the practical measures that currently taken by sample retailers to manage environmental issues in their facilities with a framework of green facility strategy being formed. The finding shows that that retailers ènvironmental initiatives mainly focus on three aspects: energy, waste and water, and the future trend is towards green building design and construction. Another trend worth noticing is that renewable energy has become popular among companies. In addition, retailer has integrated waste management with energy project, seeking to turn waste into energy.
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  • Preference ontology-oriented metric model for trustworthy Web services

    Yang Zhang   Bin Fang   Chuanyun Xu  

    Abstract The selection and optimization of trustworthy services is one of the key factors that decide whether the software based on Web services would succeed or not, so this paper proposes a preference ontology-oriented metric model for trustworthy Web services (POOMM) with the fuzzy description logics for POOMM (FDL-POOMM). POOMM evaluates the trustworthy degree of Web service by a neutral third party—Trustworthiness Metric Center, in which the trustworthy metric index system is described by preference-oriented domain ontology and FDL-POOMM calculates the trustworthy degree of Web services by processing information of ontologies, and the Trustworthy Service Intelligent Evaluating System is developed to validate the feasibility and effectiveness of POOMM. © 2010 Wiley Periodicals, Inc.
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  • Effective anisotropic velocity model from surface monitoring of microseismic events

    Yang Zhang   Leo Eisner   William Barker   Michael C. Mueller and Kevin L. Smith  

    We develop a methodology to obtain a consistent velocity model from calibration shots or microseismicity observed on a buried array. Using a layered 1D isotropic model derived from checkshots as an initial velocity model, we invert P-wave arrival times to obtain effective anisotropic parameters with a vertical axis of symmetry (VTI). The nonlinear inversion uses iteration between linearized inversion for anisotropic parameters and origin times or depths, which is specific to microseismic monitoring. We apply this technique to multiple microseismic events from several treatments within a buried array. The joint inversion of selected events shows a largely reduced RMS error indicating that we can obtain robust estimates of anisotropic parameters, however we do not show improved source locations. For joint inversion of multiple microseismic events we obtained Thomsen anisotropic parameters ε of 0.15 and δ of 0.05, which are consistent with values observed in active seismic surveys. These values allow us to locate microseismic events from multiple hydraulic fracture treatments separated across thousands of metres with a single velocity model. As a result, we invert the effective anisotropy for the buried array region and are able to provide a more consistent microseismicity mapping for past and future hydraulic fracture stimulations.
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  • Re-assembly behaviors of polystyrene-b-poly(acrylic acid) micelles

    Yang Zhang   Xing Xiao   Jian-jun Zhou   Lei Wang   Zhi-bo Li   Lin Li   Lin-qi Shi   Chi-Ming Chan  

    The re-assembly behaviors of spherical micelles of the polystyrene-b-poly(acrylic acid) (PS-b-PAA) diblock copolymer in different solvent mixtures were investigated using dynamic light scattering, transmission electron microscopy and atomic force microscopy. Depending on the nature of the solvent, PS-b-PAA micelles re-assembled from spheres to nanorings in toluene or to necklace-like aggregates in water induced by solvent evaporation. Systematic studies suggested that the re-assembly behaviors on a neutral surface are strongly correlated with the micellar surface components, the solvent polarity and the chain length of the micelle corona of the solvated blocks. We proposed that the formation of nanorings from PS-b-PAA micelles in toluene is mainly induced by the dewetting process of the solvent, while the necklace-like structure arises from the hydrogen bonding interactions among the partially dissociated PAA units. [All rights reserved Elsevier].
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