371 research outputs found

    Sampling Deviation Real-time Calibration Method for Wideband Simulator

    Get PDF
    Hardware-in-the-loop simulation is an efficient method for research on radar system.Target’s echo which offered by the simulator should be synchronized with radar on frequency, time, and range bin. However, because simulator needs to take into account of the requirements of various types of radar, it is difficult to make the clock of simulator synchronized with the clock of radar. To solve the problem, synchronous sampling deviation model is established. Influence of sampling deviation on imaging is analyzed. An engineering method is put forward to eliminate the sampling deviation. This method not only provides a reference for simulation system, but also provides a reference for the design of radar system

    Incremental Particle Swarm Optimization

    Get PDF
    AbstractBy simulating the population size of the human evolution, a PSO algorithm with increment of particle size (IPPSO) was proposed. Without changing the PSO operations, IPPSO can obtain better solutions with less time cost by modifying the structure of traditional PSO. Experimental results show that IPPSO using logistic model is more efficient and requires less computation time than using linear function in solving more complex program problems

    Improving Aerosol Simulation over South Asia for Climate and Air Quality Studies

    Get PDF
    Atmospheric pollution over South Asia attracts special attention due to its effects on regional climate, the water cycle, and human health. These effects are potentially growing owing to rising trends of anthropogenic aerosol emissions found there. However, it has been proved quite challenging to adequately represent the aerosol spatial distribution and magnitude over this critical region in global models (Pan et al. 2014), with the surface concentrations, aerosol optical depth (AOD), and absorbing AOD (AAOD) significantly underestimated, especially in October-January when the agricultural waste burning and anthropogenic aerosol dominate over dust aerosol. In this study, we aim to investigate the causes for such discrepancy in winter by conducting sets of model experiments with NASA's GEOS-5 in terms of (1) spatial resolution, (2) emission amount, and (3) meteorological fields

    The fabrication of electrochemical geophone based on FPCB process technology

    Get PDF
    The subject of the studies presented in this paper is the fabrication of electrochemical geophone, especially the electrochemical transducer with symmetrical four-electrode cell by FPCB process technology. The geophone assembled by transducer, dumbbell-shaped tube, highly-flexible membranes, electrolyte solution and signal-amplification circuit, is calibrated using a standard vibration platform, and the results show a good consistency of each geophone parameters. Coupled with low cost, the electrochemical geophone by FPCB shows a good potential application prospect

    TiO2 Nanofoam–Nanotube Array for Surface-Enhanced Raman Scattering

    Get PDF
    By tuning the anodic voltage and electrochemical reaction time, we have synthesized a series of TiO2 nanofoam–nanotube array structures via a two-step anodic oxidation process. The produced nanofoam–nanotube array demonstrated a remarkable Raman scattering enhancement. The maximum enhancement factors are 2.3 × 105 for methylene blue. Factors such as the nanotube pore size, nanofoam, and solute concentration have been investigated. The Raman scattering enhancement is attributed to the existence of the nanofoam structure, which enables multiple laser scatterings among the periodic voids and allows for the occurrence of Raman scattering. The proposed simple and inexpensive approach can promote the use of TiO2 materials for surface-enhanced Raman scattering applications in chemistry, biology, and nanoscience

    Influence of ultrasound-assisted alkali treatment on the structural properties and functionalities of rice protein

    Get PDF
    peer-reviewedThe poor solubility of rice protein (RP) limits its applications in food industry. In this study, the effects of ultrasound-assisted alkali (UAA) treatment on the solubility, structure and functional properties of RP were investigated. Using UAA treatment, the solubility of RP increased with increasing alkali concentration, reaching a maximum value of 19.79 mg/mL at an alkali concentration of 0.08 M. The solubility was improved by 230-fold compared to un-treated samples. In addition, a reduction in particle size and degradation of the protein subunit were observed. UAA seemed to unfold the protein internal structural conformation and expose buried functional groups, which are linked to good emulsifying properties and foaming properties. A decrease in zeta potential was also observed after UAA treatment, which could be the reason for the decreased stability of the emulsion. UAA treatment modified the protein structure and significantly improved solubility

    Fluctuating Two-state Light Harvesting In A Photosynthetic Membrane

    Get PDF
    The mechanism by which light is converted into chemical energy in a natural photosynthetic system has drawn considerable research interest. Using fluorescence spectroscopy and microscopic imaging, we have observed fluctuating intermolecular protein fluorescence resonant energy transfers (FRET) among light-harvesting proteins I and II (LH1 and LH2) in bacterial photosynthetic membranes. Using two-channel, FRET, photon-counting detection and a novel, two-dimensional cross-correlation function amplitude-mapping analysis, we revealed fluorescence intensity and spectral fluctuations of donor (LH2) and acceptor (LH1) fluorescence involving FRET. Our results suggest that there are dynamic coupled and noncoupled states of the light-harvesting protein assemblies in photosynthetic membranes. The light-harvesting complex assembly under ambient conditions and under water involves dynamic intermolecular structural fluctuations that subsequently disturb the degree of energy transfer coupling between proteins in the membrane. Such intrinsic and dynamic heterogeneity of the native photosynthetic membranes, often submerged under the overall thermally induced spectral fluctuations and not observable in an ensemble-averaged measurement, likely plays a critical role in regulating the light-harvesting efficiency of the photosynthetic membranes
    • …
    corecore