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Soil Fertility Self-development Under Ecological Restoration in the Zhuxi Watershed in the Red Soil Hilly Region of China

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Journal of Mountain Science 2014年第5期11卷 1231-1241页

作者： BAI Li-yue CHEN zhi-qiang CHEN zhi-biao College of Geographical Sciences Fujian Normal University Institute of Agriculture Regional Planning of Fujian Province

Current methods that utilize simple data or models to judge whether soil fertility can selfdevelop are not sufficiently rigorous. A new framework has been set up using catastrophe theory, laboratory experiment, field work, and 3S(Geographic information system, Global positioning system, and Remote sensing) to explore soil fertility catastrophe under ecological restoration, discriminate whether soil fertility can self-develop, and propose adjustment of ecological restoration measures in the Zhuxi watershed of Changting County, Fujian Province, China, which is a typical representative of the red soil hilly region of China. The results show that: 1) the soil fertility is obviously improved through the four ecological restoration measures, which impels soil fertility catastrophe. Among 89 soil samples, catastrophic soil samples and stable soil samples account for 26(29.21%) and 63(70.79%) of the samples, respectively. The four ecological restoration measures are listed in the order lowquality forest improvement > arbor–bush–herb mixed plantation > orchard improvement > closing measures according to the proportions of catastrophic soil samples. A typical soil sample in Bashilihe that can self-develop is selected as the criterion to judge the upper lobe and lower lobe of soil fertility in the process surface of the Cusp catastrophe model. Twenty-six(29.21%) were in the middle lobe, 10(11.24%) were in the upper lobe, and 53(70.79%) were in the lower lobe. The catastrophic direction of 26 catastrophic soil samples is to the upper lobe according to soil and water loss change as well as fieldwork. There is a significant positive correlation of Δ with soil and water loss change, and the lower soil and water loss relates to higher catastrophic probability. 2) Soil fertility self-development could be regionalized as "Soil fertility can self-develop" whose area was 12.74 km2(28.33%) distributed mainly in the leftmost and rightmost parts, "Soil fertility tends to self-develop" who

关键词： Soil fertility Catastrophe Ecological restoration Red soil hilly region

Glioma-conditioned Medium Blocks Endothelial Cells' Apoptosis Induced by Hypoxia and Promotes Its Angiogenesis via Up-regulation of u-PA/u-PAR

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Chinese Journal of Cancer Research 2010年第2期22卷 119-125页

作者： Xi-zhen Xu zhi-qiang Li zhi-hua Wen Department of Neurosurgery Zhongnan Hospital Wuhan University Wuhan 430071 China Laboratory of Neuro-oncology Zhongnan Hospital Wuhan University Wuhan 430071 China

Objective： To investigate the role of urokinase-type plasminogen activator/urokinase-type plasminogen receptor（u-PA/u-PAR） system in glioma angiogenesis under hypoxic conditions, we studied the effect of glioma-conditioned medium on the hypoxia induced changes in human endothelial-like ECV304 cells proliferation, apoptosis, cord formation in vitro and u-PA/u-PAR expression. Methods： MTT assay was used to examine the changes in cell proliferation. Cell apoptosis was analyzed by Hoechst 33258 staining. Matrigel cord-like formation assay was used to evaluate the angiogenesis ability of ECV304 cells in vitro. Expressions of u-PA/u-PAR mRNA were detected by quantitative real-time RT-PCR. Results： Hypoxia inhibited ECV304 cells proliferation and induced cell apoptosis. Hypoxic conditioned medium（H-CM） while not normoxic conditioned medium（N-CM） of U251 glioma ceils partially blocked the effect of hypoxia on ECV304 cells proliferation and apoptosis. H-CM of U251 glioma ceils also promoted the cord formation of ECV304 cells seeded on matrigel. When u-PA or u-PAR monoclonal antibodies were added into ECV304 cells culturing medium, cord formation ability was partially inhibited. H-CM of U251 glioma cells induced uPA and uPAR expression in ECV304 cells. Conclusion： These suggest that u-PA/u-PAR system is involved in glioma angiogenesis trigged by hypoxic microenviroment.

关键词： Endothelia Glioma Hypoxia u-PA u-PAR

A modified stratified model for the 3C 273 jet

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Chinese Journal of Astronomy and Astrophysics 2009年第5期9卷 520-528页

作者： Wen-Po Liu zhi-qiang Shen Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Graduate School of Chinese Academy of Sciences Beijing 100049 China

We present a modified stratified jet model to interpret the observed spectral energy distributions of knots in the 3C 273 jet. Based on the hypothesis of the single index of the particle energy spectrum at injection and identical emission processes among all the knots, the observed difference of spectral shape among different 3C 273 knots can be understood as a manifestation of the deviation of the equivalent Doppler factor of stratified emission regions in an individual knot from a characteristic one. The summed spectral energy distributions of all ten knots in the 3C 273 jet can be well fitted by two components; a low-energy component （radio to optical） dominated by synchrotron radiation and a high- energy component （UV, X-ray and γ-ray） dominated by inverse Compton scattering of the cosmic microwave background. This gives a consistent spectral index of α = 0.88 （Sv ∝ v^-α） and a characteristic Doppler factor of 7.4. Assuming the average of the summed spectrum as the characteristic spectrum of each knot in the 3C 273 jet, we further get a distribution of Doppler factors. We discuss the possible implications of these results for the physical properties in the 3C 273 jet. Future GeV observations with GLAST could separate the 7-ray emission of 3C 273 from the large scale jet and the small scale jet （i.e. the core） through measuring the GeV spectrum.

关键词： galaxies active -- galaxies individual (3C 273) -- galaxies jets -- radia- tion mechanisms non-thermal

Mixtures of Semiparametric Varying Coefficient Models for Longitudinal Data with Nonignorable Dropout

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Acta Mathematicae Applicatae Sinica 2010年第1期26卷 125-132页

作者： zhi-qiang Li Liu-gen Xue College of Sciences Beijing University of Chemical Technology Beijing 100029 China College of Applied Sciences Beijing University of Technology Beijing 100022 China

Informative dropout often arise in longitudinal data. In this paper we propose a mixture model in which the responses follow a semiparametric varying coefficient random effects model and some of the regression coefficients depend on the dropout time in a non-parametric way. The local linear version of the profile-kernel method is used to estimate the parameters of the model. The proposed estimators are shown to be consistent and asymptotically normal, and the finite performance of the estimators is evaluated by numerical simulation.

关键词： Nonignorable dropout, Estimating equation, Profile-kernel, Local linear estimation, Longitudinal data Semiparametric varying coefficient

Surface Patterning of Self-healing P(MMA/nBA)Copolymer for Dynamic Control Cell Behaviors

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Chinese Journal of Polymer Science 2020年第7期38卷 696-703,I0005页

作者： Su-Su Liu Ze-Hong Xiang zhi-fang Ma Xue-Wen WU qiang Shi Shing-Chung Wong Jing-Hua Yin School of Chemical Engineering Xiangtan UniversityXiangtan 411105China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Department of Mechanical Engineering University of AkronOhio 44323-3903USA

Cell behaviors are regulated by a dynamic and complex environment characterized by biophysical,mechanical and biochemical ***,most works regulate cell behaviors under static conditions or by external *** control cell adhesion and proliferation with a dynamic and mechanical environment,we pattern the surface on self-healing copolymer P(MMA/nBA).The copolymer P(MMA/nBA)with the composition of 48/52(MMA/nBA)recovers nearly 100%of its original tensile strains after 86 h of recovery from *** physical patterns on P(MMA/nBA)film are obtained over large areas and the size of the hole and the width of connecting bar are in line with the copper grid *** patterned surface tends to be fiat after 12 h with almost 75%-80%*** with cell incubation on polystyrene fiat and patterned surface of P(MMA/nBA)film without self-healing capability,the number and morphology of cells are well manipulated on the patterned surface of self-healing P(MMA/nBA)*** approach provides a convenient method for dynamically regulating the cell behaviors on the surface of self-healing materials without chemical or biological modifications.

关键词： Surface pattern Self-healing Cell behavior Dynamic

Subcarrier assignment considering path loss for multiuser OFDM systems with proportional fairness

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The Journal of China Universities of Posts and Telecommunications 2008年第2期15卷 12-17,25页

作者： XU Wen-jun HE zhi-qiang School of Information Engineering Beijing University of Posts andTelecommunications Beijing 100876 China

This article studies downlink subcarrier assignment problem to maximize rate-sum capacity subject to total power and proportional rate constraints in orthogonal frequency division multiplexing （OFDM） systems. Previous algorithms assume that the initial power is equally distributed over all subcarriers. The presence of path loss makes the assumption not correct any more. This article proposes a novel subcarrier assignment algorithm which makes full use of path loss and rate proportionality information to improve rate-sum capacity. The proposed algorithm determines optimal initial power allocation according to path losses and rate proportionalities of different users, assigns subcarriers to users in a greedy fashion, and then exchanges subcarfiers between users to obtain fairer rate distribution. Simulation results show that the proposed algorithm approximately achieves double the capacity of static assignment schemes, such as fixed frequency band approach, and obtains better performance than previous subcarrier assignment algorithms in the presence of different path losses and proportional rate requirements..

关键词： OFDM subcarrier assignment path loss

Propagation dynamics on the Fermi-Pasta-Ulam lattices

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Frontiers of physics 2013年第3期8卷 349-355页

作者： Zong-qiang Yuan zhi-Gang Zheng Department of Physics and the Beijing Hong Kong-Singapore Joint Centre for Nonlinear and Complex Systems (Beijing) Beijing Normal University Beijing 100875 China

The spatiotemporal propagation of a momentum excitation on the finite Fermi-Pasta-Ulam lattices is investigated. The competition between the solitary wave and phonons gives rise to interesting propagation behaviors. For a moderate nonlinearity, the initially excited pulse may propagate co- herently along the lattice for a long time in a solitary wave manner accompanied by phonon tails. The lifetime of the long-transient propagation state exhibits a sensitivity to the nonlinear parameter. The solitary wave decays exponentially during the final loss of stability, and the decay rate varying with the nonlinear parameter exhibits two different scaling laws. This decay is found to be related to the largest Lyapunov exponent of the corresponding Hamiltonian system, which manifests a transition from weak to strong chaos. The mean-free-path of the solitary waves is estimated in the strong chaos regime, which may be helpful to understand the origin of anomalous conductivity in the Fermi-Pasta Ulam lattice.

关键词： Fermi-Past-Ulam model solitary wave low-dimensional heat conduction

A method for automatic detection and characterization of plasma bubbles using GPS and BDS data

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Chinese Journal of Aeronautics 2021年第5期34卷 195-204页

作者： qiang LI Yanbo ZHU zhipeng WANG Kun fang National Key Laboratory of CNS/ATM School of Electronics and Information EngineeringBeihang UniversityBeijing 100191China Aviation Data Communication Corporation Beijing100191China

Detecting and characterizing Total Electron Content(TEC)depletion is important for studying the ionospheric threat due to the Equatorial Plasma Bubble(EPB)when applying the Ground-Based Augmentation System(GBAS)at low *** paper develops a robust method to automatically identify TEC depletion and derive its *** rolling barrel algorithm is used to automatically identify the TEC depletion candidate and its ***,the depletion candidates are screened by several improved techniques to distinguish actual depletions from other phenomena such as Traveling Ionospheric Disturbance(TID)or abnormal ***,based on the depletion signals from three triangular receivers,the method derives EPB parameters such as velocity,width and *** time lag and front velocity are calculated based on crosscorrelation using TEC depletions and the geometrical distribution of three triangular *** width and gradient of slope are then determined by using TEC depletion from a single *** comparison,both the station-pair method and proposed method depend on the assumption that the EPB morphology is frozen during the short time when the plasma bubble moves between the ***,our method relaxes the restriction that the baseline length should be shorter than the width of slope required by the *** relaxation is favorable for studying small-scale slope of depletions using stations of a longer *** addition,the accuracy of the width and gradient is free of impact from hardware biases and small-scale disturbance,as it is based only on the relative TEC *** method is demonstrated by processing Global Positioning System(GPS)and Bei Dou Navigation Satellite System(BDS)data on 15 August,2018,in a solar minimum cycle.

关键词： Depletion drift Ground-Based Augmentation System(GBAS) Ionosphere gradient Plasma bubble TEC depletion

Glow Discharge Plasma-Assisted Preparation of Nickel-Based Catalyst for Carbon Dioxide Reforming of Methane

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Chinese Journal of Chemical Physics 2008年第5期21卷 481-486页

作者： fang Guo Wei Chu Jun-qiang Xu Lin Zhong Department of Chemical Engineering Sichuan University Chengdu 610065 China Department of Chemical and Biological Engineering Chongqing Institute of Technology Chongqing 400050 China

A plasma-assisted method was employed to prepare Ni/γ-All2O3 catalyst for carbon dioxide reforming of methane reaction. The novel catalyst possessed higher activity and better coke-suppression performance than those of the conventional calcination catalyst. To achieve the same CH4 conversion, the conventional catalyst needed higher reaction temperature, about 50 ℃ higher than that of the N2 plasma-treated catalyst. After the evaluation test, the deactivation rate of the novel catalyst was 1.7%, compared with 15.2% for the conventional catalyst. Different from the characterization results of the calcined catalyst, a smaller average pore diameter and a higher specific surface area were obtained for the plasma-treated catalyst. The variations of the reduction peak temperatures and areas indicated that the catalyst reducibility was promoted by plasma assistance. The dispersion of nickel was also remarkably improved, which was helpful for controlling the ensemble size of metal atoms on the catalyst surface. The modification effect of plasma- assisted preparation on the surface property of alumina supported catalyst was speculated to account for the concentration increase of absorbed CO2. An enhancement of CO2 adsorption was propitious to the inhibition of carbon formation. The coke amount deposited on plasma treated catalyst was much smaller than that on the conventional catalyst.

关键词： Nickel-based catalyst Plasma CO2 reforming of CH4 Coke Adsorption of CO2