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Search Results: 1 - 10 of 107724 matches for " Junli Liang;Ding Liu "
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Two L-Shaped Array-Based 2-D DOAs Estimation in the Presence of Mutual Coupling
Junli Liang;Ding Liu
PIER , 2011, DOI: 10.2528/PIER10071701
Abstract: Recent research on the array geometrical configuration shows that the two L-shaped array (TLSA) has a lower Cramer-Rao Low-Bound (CRLB) of two-dimensional (2-D) directions-of-arrival (DOAs) estimation than other array configurations. However, in this array configuration, there are some problems to note: i) three electric angles are independently obtained from three uniformly linear subarrays on three axes, so they must be matched before solving elevation and azimuth angles from them; ii) Similar to other array geometries, the effect of mutual coupling in the TLSA on the estimation performance cannot be ignored; and iii) the conventional elevation estimators may encounter estimation failure. In this paper, we develop a new TLSA-based 2-D DOAs estimation algorithm. The key points of this paper are: i) using some particularly selecting matrices, a trilinear model is constructed to compensate the effect of mutual coupling on three subarrays. In addition, the steering vector is restored using the trilinear alternating least square method; ii) 2-D DOAs are estimated from the properly chosen elements of the restored steering vector to avoid pairing parameters and the severe performance degradation resulted from the failure in pairing; and iii) a new elevation estimator is designed to avoid estimation failure. Simulation results are presented to validate the performance of the proposed method.
Joint Azimuth-Elevation/(-Range) Estimation of Mixed Near-Field and Far-Field Sources Using Two-Stage Separated Steering Vector-Based Algorithm
Junli Liang;Ding Liu;Xianju Zeng;Wenyi Wang;Jiulong Zhang;Hongyang Chen
PIER , 2011, DOI: 10.2528/PIER10110104
Abstract: Passive source localization has wide applications in array signal processing. In the practical applications, the observations collected by an array may be ``arbitrary"-field signals, i.e., which are either mixed near-field and far-field signals or multiple near-field signals or multiple far-field signals. With a cross array, a two-stage separated steering vector-based algorithm is developed to localize ``arbitrary"-field narrowband sources in the spherical coordinates. The key points of this paper are: i) different physical steering vectors of near-field and far-field sources are transformed into the virtual ones with the same form, thus linearizing the quadratic phases of near-field sources and allowing the same operations for near-field and far-field sources; ii) the virtual steering vector is separated into two parts and restored by introducing a special phase angle, and thus it is used to estimate the azimuth-elevation arrival-angles of ``arbitrary"-field sources; and iii) special Hermitian matrices are constructed using the separated physical steering vector and their eigenvalue decomposition (EVD) are performed, thus the ranges of near-field sources are easily obtained from the eigenvector being corresponding to the smallest eigenvalue. The proposed algorithm can localize ``arbitrary"-field sources without pairing parameters and multidimensional search. Simulation results are provided to validate the performance of the proposed method.
Global stability for delay SIR epidemic model with vertical transmission  [PDF]
Junli Liu, Tailei Zhang
Open Journal of Applied Sciences (OJAppS) , 2012, DOI: 10.4236/ojapps.2012.24B001
Abstract: A SIR epidemic model with delay, saturated contact rate and vertical transmission is considered. The basic reproduction number is calculated. It is shown that this number characterizes the disease transmission dynamics: if, there only exists the disease-free equilibrium which is globally asymptotically stable; if, there is a unique endemic equilibrium and the disease persists, sufficient cond- itions are obtained for the global asymptotic stability of the endemic equilibrium.
4-D parameter estimation of narrowband sources based on parallel factor analysis
JunLi Liang
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-008-0271-z
Abstract: A novel algorithm is presented in this paper to jointly estimate frequency, two-dimensional (2-D) direction-of-arrival (DOA), and range of near-field narrowband sources. The proposed method extends the parallel factor (PARAFAC) analysis model from the common data-and subspace-domain to the cumulant one, and forms three-way arrays by using the five cumulant matrices obtained from the array outputs, and analyzes the uniqueness of low-rank decomposition of the three-way arrays, then jointly estimates source parameters via the low-rank decomposition. In comparison with the conventional methods, the proposed method alleviates the loss of the array aperture, and avoids pairing parameters. What is more important, this algorithm can deal with mixed far-field and near-field sources. Finally, the simulation results validate the performance of the proposed method.
Performance Analysis of Induced Draft Fan Driven by Steam Turbine for 1000 MW Power Units  [PDF]
Jianling Deng, Feifei Liang, Yang Ding, Zhiping Yang, Gang Xu, Jizhen Liu
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B263
Abstract:

Boiler fan is the main power consumption device in thermal power units and the induced draft fan accounted for the largest proportion. Reducing the energy consumption rate of induced draft fan is the main path to reduce the power consumption rate of thermal power units. The induce fan driven by small turbine is greatly effective for reducing the power consumption rate and the supply coal consumption rate in large thermal power plant. Take 1000 MW power units for example, the selection of steam source for steam turbine were discussed and economic performance of the unit under different steam source was compared in this paper. The result shows that compared with the motor driven method, there is about 1.6 g/kWh decrease in supply coal consumption rate driven by the fourth stage extraction steam; whereas there is about 2.5 g/kWh decrease in supply coal consumption rate driven by the fifth stage extraction steam.

Existence of stochastic entropy solutions for stochastic scalar balance laws with Lipschitz vector fields
Jinlong Wei,Liang Ding,Bin Liu
Mathematics , 2014,
Abstract: In this paper, we consider a scalar stochastic balance law and gain the existence for stochastic entropy solutions. Our proof relies on the BGK approximation and the generalized It\^{o} formula. Moreover, as an application, we derive the existence of stochastic entropy solutions for stochastic Buckley-Leverett type equations.
Determination of okadaic acid related toxins from shellfish (sinonovacula constricta) by high performance liquid chromatography tandem mass spectrometry  [PDF]
Hai-qi Zhang, Weicheng Liu, Xin He, Li-jun Liang, Wenyong Ding, Zhong-yang He
Agricultural Sciences (AS) , 2013, DOI: 10.4236/as.2013.45B001
Abstract:

Consumption of shellfish contaminated with algal toxins produced by marine dinoflagellates can lead to diarrhetic shellfish poisoning (DSP). It was therefore essential that there are analytical techniques to identify and quantify DSP toxins in shellfish. This new methodology could facilitate DSP monitoring and create a means of rapidly responding to incidents threatening public health. In the last years there were different analytical methods for DSP, such as mouse bioassay and LC-FLD. With the development of instrument, Liquid chromatography-mass spectrometry was substituted for other analytical methods with its good sensitivity and selectivity and without derivatization for the determination of DSP. In this report, a high performance liquid chromatogra-phytandem mass spectrometric(HPLC-MS/MS)method was developed for the simultaneous determination of okadaic acid (OA) and dinophysistoxins(DTX1) in Sinonovacula constricta. Optimization of pretreatment experiment was carried out to maximize recoveries and the effectiveness. The analytes were determined under multi-reactions monitoring (MRM) scan type with tandem mass analyzer using negative ion electrospray ionization (-ESI) mode .Finally, the detection and identification of OA and DTX-1 were based upon their retention times (RT) and the fragmentation patterns of their mass spectra. The method of LOQ for the two poisons was 0.02 mg·kg-1.The real sample test showed that this method could be used for sensitive, fast, and accurate determination of the two diarrheic shellfish poisons in shellfish.

Nano-Ferric Oxide Promotes Watermelon Growth  [PDF]
Meng Wang, Xiaoping Liu, Jing Hu, Junli Li, Jin Huang
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2015, DOI: 10.4236/jbnb.2015.63016
Abstract: With the rapid growing of nanotechnology, the effects of nanomaterials released into the environment on plants have drawn more and more attention. Iron is an element essential for plant growth and development. Iron is involved in chlorophyll formation; iron deficiency will cause a plant disorder known as chlorosis. However, whether iron in nano-ferric oxide can be absorbed by plants were rarely concerned. Nano-ferric oxide might promote the growth and development of plants in a suitable concentration. An experiment was designed to evaluate whether nano-ferric oxide can be used to treat chlorosis and the physiological changes of plants in nano-ferric oxide environment. Watermelon was chosen as the experimental plant. Seedlings of watermelon plants were grown in full nutrient solution without iron for 2 weeks until the leaves got yellow. Then the seedlings were treated with different concentrations of nano-ferric oxide (0, 20, 50, 100 mg/L) and 50 mmol/L of EDTA-Fe(II) for a month. The control group seedlings were still grown in full nutrient solution without any iron. Indicators such as activity of antioxidase like superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and content of malondialdehyde (MDA) and soluble protein were studied to measure the physiological effects nano-ferric oxide might have on watermelon. It was observed that the leaves reverted green. Experimental data showed that watermelon absorbed iron from nano-ferric oxide, and nano-ferric oxide promoted watermelon growth in some ways in a suitable concentration.
PKCα translocation from mitochondria to nucleus is closely related to induction of apoptosis in gastric cancer cells
Wu Qiao,Liu Su,Ding Liang,Ye Xiaofeng,Su Wenjin
Science China Life Sciences , 2002, DOI: 10.1360/02yc9026
Abstract: PKCs have been implicated in the regulation of cellular differentiation, proliferation, apoptosis and signal transduction. It was demonstrated in this study that PKCα was located both at mitochondria and in cytosol in gastric cancer cell line BGC-823. Treatment of cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) resulted in the translocation of PKCα from both mitochondria and cytosol to nucleus as clearly shown by laserscanningconfocal microscopy, while the protein level of PKCα was not changed by TPA treatment as detected by Western blot. The results also revealed that TPA-induced translocation of PKCα was in close association with apoptosis induction, and such association was further affirmed by other experiments where various apoptotic stimuli and specific inhibitors of PKC were used. Taken together, these findings indicate that translocation of PKCα from both mitochondria and cytosol to nucleus in gastric cancer cell is accompanied by induction of apoptosis, and may imply a new mechanism of the potential linking between cell apoptosis and PKCα translocation.
Electromagnetic Wave Propagation Through a Slab Waveguide of Uniaxially Anisotropic Dispersive Metamaterial
Song-Hua Liu;Chang-Hong Liang;Wei Ding;Liang Chen;Wei-Tao Pan
PIER , 2007, DOI: 10.2528/PIER07071905
Abstract: The characteristics of the guided electromagnetic wave propagation through a slab waveguide of uniaxially anisotropic dispersive metamaterial are investigated. Taking the cold plasma media model with ω < ω < ω as an example,the mode classification established in terms of the operating angular frequency ω of the slab waveguide. The results indicate that the mode properties are closely dependent on the frequency. When ω < ω < ω there are infinite guided modes. It is also found that when ω < ω < ω,there may be multiple solutions of the propagating mode with imaginary transverse wave number in a slab waveguide with thickness less than a certain value.
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