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Search Results: 1 - 10 of 44454 matches for " Haitao Wu "
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Research on DOA Estimation of Multi-Component LFM Signals Based on the FRFT  [PDF]
Haitao QU, Rihua WANG, Wu QU, Peng ZHAO
Wireless Sensor Network (WSN) , 2009, DOI: 10.4236/wsn.2009.13023
Abstract: A novel algorithm for the direction of arrival (DOA) estimation based on the fractional Fourier transform (FRFT) is proposed. Firstly, using the properties of FRFT and mask processing, Multi-component LFM sig-nals are filtered and demodulated into a number of stationary single frequency signals. Then the one-dimensional (1-D) direction estimation of LFM signals can be achieved by combining with the tradi-tional spectrum search method in the fractional Fourier (FRF) domain. As for the multi-component LFM signals, there is no cross-term interference, the mean square error (MSE) and Cramer-Rao bound (CRB) are also analyzed which perfects the method theoretically, simulation results are provided to show the validity of our method. The proposed algorithm is also extended to the uniform circular array (UCA), which realizes the two-dimensional (2-D) estimation. Using the characteristics of time-frequency rotation and demodulation of FRFT, the observed LFM signals are demodulated into a series of single frequency ones; secondly, operate the beam-space mapping to the single frequency signals in FRF domain, which UCA in array space is changed into the virtual uniform circular array (ULA) in mode space; finally, the DOA estimation can be realized by the traditional spectral estimation method. Compared with other method, the complex time-frequency cluster and the parameter matching computation are avoided; meanwhile enhances the esti-mation precision by a certain extent. The proposed algorithm can also be used in the multi-path and Doppler frequency shift complex channel, which expands its application scope. In a word, a demodulated DOA esti-mation algorithm is proposed and is applied to 1-D and 2-D angle estimation by dint of ULA and UCA re-spectively. The detailed theoretical analysis and adequate simulations are given to support our proposed al-gorithm, which enriches the theory of the FRFT.
Mitigative Effect of Bacillus subtilis QM3 on Root Morphology and Resistance Enzyme Activity of Wheat Root under Lead Stress  [PDF]
Yang Hao, Haitao Wu, Yanfang Liu, Qingping Hu
Advances in Microbiology (AiM) , 2015, DOI: 10.4236/aim.2015.56048
Abstract: Lead (Pb) is an environmental pollutant extremely toxic to plants and other living organisms including humans. In order to research the relieve effect of Bacillus subtilis QM3 on wheat roots (Triticum aestivum L.), after wheat seeds germination for two days, wheat root caused, the experimental materials were divided into four large groups and each large group was placed in 6 petri dishes as six small groups, and then four large groups respectively cultivated with sterile water (CK), 108 CFU/ml B. subtilis QM3 (B1), 107 CFU/ml B. subtilis QM3 (B2) and 106 CFU/ml B. subtilis QM3 (B3) for 2 days, after that stressed with lead nitrate, Pb (NO)2, Pb2+ concentration calculation at five concentrations (50, 250, 500, 1000, 2000 mg/L), sterile water and different Pb2+ concentration liquid respectively cultivated the 6 small groups in each large group measuring root morpholog and assaying changes of antioxidant enzyme activity. The results showed that: with the increase of the Pb2+ concentration, root morphology index and the activity of antioxidant enzyme increased first and then decreased. Root morphology index reached the maximum in 50 mg/L Pb2+ concentration. B. subtilis QM3 clearly promoted the growth of the root and the
A Numerical Approach to a Nonlinear and Degenerate Parabolic Problem by Regularization Scheme  [PDF]
Haitao Cao
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.25012
Abstract: In this work we propose a numerical scheme for a nonlinear and degenerate parabolic problem having application in petroleum reservoir and groundwater aquifer simulation. The degeneracy of the equation includes both locally fast and slow diffusion (i.e. the diffusion coefficients may explode or vanish in some point). The main difficulty is that the true solution is typically lacking in regularity. Our numerical approach includes a regularization step and a standard discretization procedure by means of C0-piecewise linear finite elements in space and backward-differences in time. Within this frame work, we analyze the accuracy of the scheme by using an integral test function and obtain several error estimates in suitable norms.
Spatial distribution of ant mounds and effects on soil physical properties in wetlands of the Sanjiang plain, China

Haitao Wu,Donghui Wu,Xianguo Lu,Xiaomin Yin,

生态学报 , 2010,
Abstract:
Effects of Pyridoxine on Selected Appetite Regulating Peptides mRNA Expression in Hypothalamic PVN/ARC Nuclei and Gastrointestinal Tract Tissues  [PDF]
Lei Liu, Haoqi Wang, Haitao Sun, Chunyan Fu, Hongli Liu, Yuqing Sun, Xianghua Xu, Weiji Chen, Wenqiang Wu, Fuchang Li
Advances in Bioscience and Biotechnology (ABB) , 2017, DOI: 10.4236/abb.2017.89020
Abstract: An experiment was conducted to investigate the effect of dietary pyridoxine on the gene expression of appetite-regulating peptides in the hypothalamus and gastrointestinal tract of rabbits. Thirty-two rabbits were randomly divided into 2 treatments for 8 weeks (16 replicates/group and 1 rabbit/replicate). The treatments were fed a basal diet (control, measured pyridoxine content is 4.51 mg/kg) and the basal diet with a pyridoxine supplementation at 10 mg/kg (pyridoxine, measured pyridoxine content is 14.64 mg/kg). The results showed that dietary pyridoxine did not significantly alter the mRNA levels of neuropeptide Y, agouti related peptide, pro-opiomelanocortin and cocaine, amphetamine regulated transcript, peptide YY and cholecystokinin in arcuate nucleus, peptide YY in jejunum and ileum, and cholecystokinin in duodenum, jejunum and ileum (P > 0.05). Compared with the control, the mRNA levels of corticotropin-releasing hormone and melanocortin 4 receptor in paraventricular nuclei and peptide YY in duodenum were significantly decreased after pyridoxine treatment (P < 0.05). In conclusion, the appetite genes of melanocortin 4 receptor and corticotropin-releasing hormone in paraventricular nuclei and peptide YY in duodenum are involved in the pyridoxine-caused hyperphagia.
A satellite clock error correction method in the wide area differential system
ChengLin Cai,XiaoHui Li,HaiTao Wu,XingWang Chang
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0686-1
Abstract: Based on the deep analysis of the wide area differential principle on the separation of satellite ephemeris errors and clock errors, the similarities and differences between the absolute separation of satellite ephemeris errors under time synchronization among the differential stations and relative separation of them under no time synchronization among them are analyzed. A one-station correction method of satellite clock errors including the 1st and the 2nd step correction is given under no time synchronization among these secondary stations, and the backward inference algorithm of the second correction of satellite clock errors is proposed. Through simulation analysis, satellite time service accuracy with code phase measurement can reach 5–7 ns, and that with carrier phase smoothing pseudo-range can reach 1–3 ns.
Impact of technology advances on China’s CO2 emission reduction
YouFei Zheng,HaiTao Li,RongJun Wu,LianXi Wang
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-010-3241-1
Abstract: Global warming tends to be the major characteristics of the dramatic global climate change. To deal with these changes, the impact of reducing greenhouse gas (GHG) emission on Chinese future economic and social development has to be assessed. In this paper, a Regional Integrated model of Climate and the Economy (RICE), which is well known and accepted widely, has been used for Chinese economic assessment of climate change after introduction, assimilation and verification. Based on a sensitivity analysis of technical parameters in the RICE model and constrained targets proposed for energy saving and emissions reduction technological advance programs of China from 2000 to 2050, the economic impact of the programs is examined. The results indicate that when technology advances, Chinese CO2 emission, climate loss, and the growth rate of atmospheric CO2 concentration and temperature will all decrease. It is assumed that in 2010, the CO2 emission is 20% lower than in 2005, CO2 emission in 2050 would only double the level in 2000, the accumulative CO2 emission would be decreased by 12.4 GtC, and the atmospheric CO2 concentration and temperature in 2050 would reduce by 35 GtC and 0.04°C respectively from 2000 to 2050. The accumulative climate loss from 2000 to 2050 will drop down by 4.6 billion dollar, which only accounts for 6% of the global total benefits. However, the economic benefit the developed countries will obtain is 10 times that for China under such a technological advance scenario. The decrease of the CO2 emission control rate is 1% in cooperation policy while 4.6% in non-cooperation policy, which would relieve China’s burden in the control of CO2 total emission and thereby benefit China in participation of the international cooperation for CO2 emission reduction.
Effect of acetazolamide on stable carbon isotope fractionation in Chlamydomonas reinhardtii and Chlorella vulgaris
YanYou Wu,Ying Xu,HaiTao Li,DeKe Xing
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-011-4861-9
Abstract: The effect of extracellular carbonic anhydrase (CAex) on stable carbon isotope fractionation in algae is still unclear. The stable carbon isotope composition and algal growth in the presence and absence of the membrane-impermeable CA inhibitor acetazolamide were compared in Chlamydomonas reinhardtii and Chlorella vulgaris. The CAex of both algal species contributed about 9‰ of the stable carbon isotope fractionation and exhibited a dosage effect. Therefore, evidence in vivo that CAex leads to a larger carbon isotope fractionation of algae is presented.
Preparation and thermal conductivity of CuO nanofluid via a wet chemical method
Zhu Haitao,Han Dongxiao,Meng Zhaoguo,Wu Daxiong
Nanoscale Research Letters , 2011,
Abstract: In this article, a wet chemical method was developed to prepare stable CuO nanofluids. The influences of synthesis parameters, such as kinds and amounts of copper salts, reaction time, were studied. The thermal conductivities of CuO nanofluids were also investigated. The results showed that different copper salts resulted in different particle morphology. The concentration of copper acetate and reaction time affected the size and shape of clusters of primary nanoparticles. Nanofluids with different microstructures could be obtained by changing the synthesis parameters. The thermal conductivities of CuO nanofluids increased with the increase of particle loading.
Interference Mitigation for Coexistence of Heterogeneous Ultra-Wideband Systems
Zhang Yongjing,Wu Haitao,Zhang Qian,Zhang Ping
EURASIP Journal on Wireless Communications and Networking , 2006,
Abstract: Two ultra-wideband (UWB) specifications, that is, direct-sequence (DS) UWB and multiband-orthogonal frequency division multiplexing (MB-OFDM) UWB, have been proposed as the candidates of the IEEE 802.15.3a, competing for the standard of high-speed wireless personal area networks (WPAN). Due to the withdrawal of the standardization process, the two heterogeneous UWB technologies will coexist in the future commercial market. In this paper, we investigate the mutual interference of such coexistence scenarios by physical layer Monte Carlo simulations. The results reveal that the coexistence severely degrades the performance of both UWB systems. Moreover, such interference is asymmetric due to the heterogeneity of the two systems. Therefore, we propose the goodput-oriented utility-based transmit power control (GUTPC) algorithm for interference mitigation. The feasible condition and the convergence property of GUTPC are investigated, and the choice of the coefficients is discussed for fairness and efficiency. Numerical results demonstrate that GUTPC improves the goodput of the coexisting systems effectively and fairly with saved power.
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