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Showing papers by "Shanghai University published in 2005"


Journal ArticleDOI
TL;DR: It is concluded that 3'-end methylation is a common step in miRNA and siRNA metabolism and likely protects the 3' ends of the small RNAs from the uridylation activity.

824 citations


Journal ArticleDOI
TL;DR: In this paper, the Laplace transform theory was used for synchronization of the fractional Lu system, and the suitable conditions for achieving synchronization of this fractional differential system were derived by using the La Place transform theory.
Abstract: Chaos synchronization of the fractional Lu system is theoretically and numerically studied by two methods. The suitable conditions for achieving synchronization of this fractional differential system are derived by using the Laplace transform theory. Numerical simulations coincide with the theoretical analysis.

362 citations


Journal ArticleDOI
TL;DR: From the numerical results obtained by the new method to well-known periodic problems, show the superior efficiency, accuracy, stability of the method presented.

327 citations


Journal ArticleDOI
TL;DR: In this article, molecular composition and compound-specific carbon and hydrogen stable isotope ratios of leaf wax n-alkanes are presented for 26 plant species operating C3, C4 and CAM photosynthetic pathways.

276 citations


Journal ArticleDOI
Li-Qun Chen1
TL;DR: In this article, the authors present the governing equations with large amplitude, and review progress on discretized or direct approximate analytical analyses and numerical approaches based on the Galerkin method or the finite difference method.
Abstract: In this paper, research on transverse vibrations of axially moving strings and their control is thoroughly reviewed. In the last few decades, there have been extensive studies on analysis and control of transverse vibrations of axially moving strings because of the wide applications of many engineering devices that axially moving strings represent. In the investigations adopting linear models of moving strings, the paper summarizes recent studies on modal analysis, complicatedly constrained strings, coupled vibrations, and parametric vibration, as well as some early results. In the investigations adopting nonlinear models of moving strings, the paper presents the governing equations with large amplitude, and reviews progress on discretized or direct approximate analytical analyses and numerical approaches based on the Galerkin method or the finite difference method. Furthermore, investigations are reported on modeling of damping mechanisms as viscoelastic materials, coupled vibration of power transmission systems, and bifurcation and chaos. The state of the art of active control of moving strings is surveyed on controllability and observability, the Laplace transform domain analysis and the energy analysis, nonlinear vibration control and adaptive vibration control. Finally, future research directions are suggested such as nonlinear vibration of moving strings under complex constraints and couplings, energetics of nonlinear and time-varying strings, bifurcation and chaos in transverse motion of moving strings, control of hybrid systems containing moving strings, robust and adaptive controls of nonlinear moving strings, and experimental investigations. In this review article there are 242 references cited. @DOI: 10.1115/1.1849169#

273 citations


Journal ArticleDOI
TL;DR: A centrifugal force model for pedestrian dynamics is developed and is able to reproduce the self-organization phenomena of lane formation for sparse flows and the jamming probability due to the arching at exits for crowd flows is provided.
Abstract: In this paper, a centrifugal force model is developed for pedestrian dynamics. The effects of both the headway and the relative velocity among pedestrians are taken into account, which can be expressed by a "centrifugal force" term in dynamic equation. The jamming probability due to the arching at exits for crowd flows is provided. A quantitative analysis of the crowd flowing out of a hall shows that the average leaving time T is a function of the exit width W in negative power. The related simulation indicates that the proposed model is able to reproduce the self-organization phenomena of lane formation for sparse flows.

247 citations


Journal ArticleDOI
TL;DR: Two lattice traffic models are proposed by incorporating a cooperative driving system and the results show that considering more than one site ahead in vehicle motion leads to the stabilization of the system.
Abstract: Two lattice traffic models are proposed by incorporating a cooperative driving system. The lattice versions of the hydrodynamic model of traffic flow are described by the differential-difference equation and difference-difference equation, respectively. The stability conditions for the two models are obtained using the linear stability theory. The results show that considering more than one site ahead in vehicle motion leads to the stabilization of the system. The modified Korteweg-de Vries equation (the mKdV equation, for short) near the critical point is derived by using the reductive perturbation method to show the traffic jam which is proved to be described by kink-anti-kink soliton solutions obtained from the mKdV equations.

240 citations



Journal ArticleDOI
TL;DR: In this paper, the voltammetric behavior of dihydroxybenzene isomers was studied with glassy carbon electrodes modified with multi-wall carbon nanotubes.

195 citations


Journal ArticleDOI
TL;DR: In this paper, it has been found that aliovalent-substituted polycrystalline materials have significantly enhanced multiferroic properties, such as electric field induced polarization and remanent magnetization.
Abstract: It has been found that aliovalent-substituted $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}\text{\ensuremath{-}}\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$-based polycrystalline materials have significantly enhanced multiferroic properties. Relative to unmodified $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}$, our results for modified $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}\text{\ensuremath{-}}\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$-based ceramics reveal: (i) a dramatic increase in the electric-field-induced polarization; and (ii) the establishment of a remanent magnetization. The results evidence the destruction of a space-modulated spin structure in bulk materials, via substituent effects, releasing a latent magnetization locked within the cycloid.

176 citations


Journal ArticleDOI
TL;DR: This letter proposes a novel steganographic scheme that employs human vision sensitivity to hide a large amount of secret bits into a still image with a high imperceptibility by using a series of symbols in a notation system with multiple bases.
Abstract: This letter proposes a novel steganographic scheme that employs human vision sensitivity to hide a large amount of secret bits into a still image with a high imperceptibility. In this method, data to be embedded are converted into a series of symbols in a notation system with multiple bases. The specific bases used are determined by the degree of local variation of the pixel magnitudes in the host image so that pixels in busy areas can potentially carry more hidden data. Experimental results are given to show the advantage of this adaptive technique.

Journal ArticleDOI
TL;DR: Numerical simulations show that this method of the generalized projective synchronization works very well, which can also be applied to other chaotic systems.
Abstract: In the present paper, a simple but efficient control technique of the generalized projective synchronization is applied to a unified chaotic system. Numerical simulations show that this method works very well, which can also be applied to other chaotic systems.

Journal ArticleDOI
Debin Huang1
TL;DR: A simple adaptive-feedback scheme is proposed to strictly synchronize almost all chaotic systems, which is analytical, and simple to implement in practice, and quite robust against the effect of noise.
Abstract: Based on the invariance principle of differential equations, a simple adaptive-feedback scheme is proposed to strictly synchronize almost all chaotic systems. Unlike the usual linear feedback, the variable feedback strength is automatically adapted to completely synchronize two almost arbitrary identical chaotic systems, so this scheme is analytical, and simple to implement in practice. Moreover, it is quite robust against the effect of noise. The famous Lorenz and Rossler hyperchaos systems are used as illustrative examples.

Journal ArticleDOI
TL;DR: In this paper, three different versions of optimal velocity models are examined and the stability conditions of the models are obtained by using the linear stability theory, and the general solutions are given for, which can lead to specific solutions in previous work.
Abstract: The jams in the congested traffic are related with various density waves, which might be governed by the nonlinear wave equations, such as the Korteweg–de-Vries (KdV) equation, the Burgers equation and the modified Korteweg–de-Vries (mKdV) equation. Three different versions of optimal velocity models are examined. The stability conditions of the models are obtained by using the linear stability theory. The KdV equation near the neutral stability line and the mKdV equation around the critical point are derived by applying the reductive perturbation method, respectively. The traffic jams could be thus described by the KdV and kink–antikink soliton solutions for the two kinds of equations. The general solutions are given for, which can lead to specific solutions in previous work. Moreover, they are applied to solve a new model—the full velocity difference model and the corresponding KdV and kink–antikink soliton solutions could be quickly obtained, which demonstrates the general solutions presented herein are useful.

Journal ArticleDOI
TL;DR: A sensitive, high-throughput real-time (RT)-PCR technique for estimating transgene copy number in GM rice, which showed that rearrangements of the T-DNA occurred more frequently than is generally believed in transgenic rice.
Abstract: In transgenic plants, transgene copy number can greatly influence the expression level and genetic stability of the target gene, making estimation of transgene copy number an important area of genetically modified (GM) crop research. Transgene copy numbers are currently estimated by Southern analysis, which is laborious and time-consuming, requires relatively large amounts of plant materials and may involve hazardous radioisotopes. We report here the development of a sensitive, high-throughput real-time (RT)-PCR technique for estimating transgene copy number in GM rice. This system uses TaqMan quantitative RT-PCR and comparison to a novel rice endogenous reference gene coding for sucrose phosphate synthase (SPS) to determine the copy numbers of the exogenous β-glucuronidase (GUS) and hygromycin phosphortransferase (HPT) genes in transgenic rice. The copy numbers of the GUS and HPT in primary rice transformants (T0) were calculated by comparing quantitative PCR results of the GUS and HPT genes with those of the internal standard, SPS. With optimized PCR conditions, we achieved significantly accurate estimates of one, two, three and four transgene copies in the T0 transformants. Furthermore, our copy number estimations of both the GUS reporter gene and the HPT selective marker gene showed that rearrangements of the T-DNA occurred more frequently than is generally believed in transgenic rice.

Journal ArticleDOI
TL;DR: The powder and extracts of Psoralea corylifolia L. were tested in lard at 100 °C by using the oxidative stability instrument (OSI) and were found to have strong antioxidant effects as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, a new model for predicting the reacted fraction of hydriding/dehydriding in powder hydrogen storage materials has been developed, which offers an analytic form expressing the reaction fraction of hydrogen absorption/desorption (A/D) as a function of time, temperature and pressure explicitly.

Journal ArticleDOI
TL;DR: The solid oxide membrane (SOM) process is an emerging technology for the environmentally friendly extraction of high-energy-content metals such as magnesium, tantalum, and titanium directly from their respective oxides.
Abstract: The solid oxide membrane (SOM) process is an emerging technology for the environmentally friendly extraction of high-energy-content metals such as magnesium, tantalum, and titanium directly from their respective oxides. This paper reports on the recent success of the SOM process for magnesium production from magnesium oxide dissolved in fluoride-based fluxes in the temperature range 1150 °C to 1300 °C. This process employs an inert oxygen-ion-conducting stabilized zirconia membrane to separate the inert cathode in the flux from the anode. When the applied electrical potential between the electrodes exceeds the dissociation potential of magnesium oxide, oxygen ions are pumped out of the melt and through the zirconia membrane to the anode where they are oxidized. Reduced magnesium evolves at the cathode as a vapor and is condensed in a separate chamber yielding a high-purity product. The SOM cell has been electrochemically characterized, and key concepts related to MgO dissociation, leakage current, and mass transfer relevant to the SOM process are explained.

Journal ArticleDOI
TL;DR: In this paper, the authors considered bisymmetric and centrosymmetric solutions to certain matrix equations over real quaternion algebra @? and obtained necessary and sufficient conditions for the matrix equation AX = C.
Abstract: In this paper we consider bisymmetric and centrosymmetric solutions to certain matrix equations over the real quaternion algebra @?. Necessary and sufficient conditions are obtained for the matrix equation AX = C and the following systemsA"1X=C"1,A"1X=C"1,XB"3=C"3,A"2X=C"2, to have bisymmetric solutions, and the systemA"1X=C"1,A"3XB"3=C"3, to have centrosymmetric solutions. The expressions of such solutions of the matrix and the systems mentioned above are also given. Moreover a criterion for a quaternion matrix to be bisymmetric is established and some auxiliary results on other sets over @? are also mentioned.

Journal ArticleDOI
TL;DR: In this article, an analytical molecular mechanics model is established to relate the chirality and size-dependent elastic properties of a single-walled carbon nanotube to its atomic structure.
Abstract: An analytical molecular mechanics model is established to relate the chirality- and size-dependent elastic properties of a single-walled carbon nanotube to its atomic structure. Properties at different length scales are directly connected by the derived closed-form expressions. The effects of tube chirality and tube diameter are investigated. The present analytical results are helpful to the understanding of elastic properties of carbon nanotubes, and thus are important for the application of carbon nanotubes as building blocks of nanomechanical devices.

Journal ArticleDOI
TL;DR: In this article, as-prepared ZnO nanorods are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and TEM.
Abstract: ZnO nanorods are prepared by a hydrothermal process with cetyltrimethylammonium bromide (CTAB) and zinc powder at 182°C. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The gas sensing properties of the materials have been investigated. The results indicate that the as-prepared ZnO nanorods are uniform with diameters of 40–80 nm and lengths about 1 μm, the relatively high sensitivity and stability of these sensors made from ZnO nanorods demonstrate the potential for developing a new class of stable and very sensitive sensors.

Journal ArticleDOI
TL;DR: The boundary element-free method as discussed by the authors is a meshless method of boundary integral equation and is a direct numerical method compared with others, in which the basic unknowns are the real solutions of the nodal variables and the boundary conditions can be applied easily.
Abstract: The moving least-square approximation is discussed first. Sometimes the method can form an ill-conditioned equation system, and thus the solution cannot be obtained correctly. A Hilbert space is presented on which an orthogonal function system mixed a weight function is defined. Next the improved moving least-square approximation is discussed in detail. The improved method has higher computational efficiency and precision than the old method, and cannot form an ill-conditioned equation system. A boundary element-free method (BEFM) for elastodynamics problems is presented by combining the boundary integral equation method for elastodynamics and the improved moving least-square approximation. The boundary element-free method is a meshless method of boundary integral equation and is a direct numerical method compared with others, in which the basic unknowns are the real solutions of the nodal variables and the boundary conditions can be applied easily. The boundary element-free method has a higher computational efficiency and precision. In addition, the numerical procedure of the boundary element-free method for elastodynamics problems is presented in this paper. Finally, some numerical examples are given.

Journal ArticleDOI
TL;DR: This approach is based on a simple nonlinear function, which is deduced by analyzing the geometry of measurement system and hence perfectly describes the mapping between the depth map and the phase-difference distribution.
Abstract: This paper presents a novel calibration approach for determining the mapping relationship between the depth map and the phase difference in fringe projection profilometry. This approach is based on a simple nonlinear function, which is deduced by analyzing the geometry of measurement system and hence perfectly describes the mapping between the depth map and the phase-difference distribution. The calibration is implemented by translating a target plane to a sequence of given positions with known depths, and measuring its phase distributions. A least-squares estimation algorithm with linear computation is deduced to retrieve the related parameters and to reconstruct the mapping function. Both computer simulation and experiment are carried out to demonstrate the validity of this technique.

Journal ArticleDOI
TL;DR: In this paper, a necessary and sufficient condition for the existence and the expression of the general solution to the system of matrix equations over real quaternion algebra @? is given.
Abstract: In this paper, we consider the system of matrix equations, A"1X = C"1, A"2X = C"2, A"3XB"3 = C"3, and A"4XB"4 = C"4, over the real quaternion algebra @?. A necessary and sufficient condition for the existence and the expression of the general solution to the system are given. As particular cases, the corresponding results on other systems over @? are also obtained.

Journal ArticleDOI
TL;DR: In this paper, an ω-symmetrically coupled system consisting of identical fractional-order differential systems including chaotic and non-chaotic systems is investigated, and it is shown that the lower the order of the fractional system, the longer the time for achieving synchronization at a fixed coupling strength.

Journal ArticleDOI
TL;DR: In this paper, the morphological structure of carbon nanotubes was investigated by transmission electron microscopy (TEM), X-ray Diffraction (XRD), and Raman spectroscopy.

Proceedings ArticleDOI
12 Dec 2005
TL;DR: An optimization of ad hoc on-demand multipath distance vector (OAOMDV) is presented to solve the "route cutoff" problem in AOMVV and simulation results show the performance improvement.
Abstract: To avoid frequent route discovery, various multipath routing protocol has been proposed based on the existing single path routing protocol in ad hoc networks. Ad hoc on-demand multipath distance vector (AOMDV) is one of extensions to the well-studied ad hoc on distance vector (AODV). In this paper an optimized AOMDV (OAOMDV) is presented to solve the "route cutoff" problem in AOMDV. The proposed protocol adds a new scheme into AOMDV and simulation results show the performance improvement

Journal ArticleDOI
TL;DR: The meshless manifold method is based on the partition of unity method and the finite cover approximation theory which provides a unified framework for solving problems dealing with both continuum with and without discontinuities.

Journal ArticleDOI
TL;DR: Most of the cells (approx 90%) lost the resistance in the presence of 5 mg/L Zeocin during subculturing, which was consistent with the observations of both rearranged and episomal plasmid DNA existed in the cells.
Abstract: An electroporation procedure has been described for introducing plasmid DNA into Dunaliella salina cells. By this procedure, a bulk of plasmid DNA was delivered into the cells and retained for at least 3 d. Reverse transcriptase polymerase chain reaction (RT-PCR) and sequencing analyses indicated that the transcription and pre-mRNA splicing of ble gene (contributing the Zeocin resistance) were detected in the cells as early as 1 h after the electroporation. Individual colonies could retain the resistance to 10 mg/L Zeocin for at least 6 mo. Subsequent Southern blot analysis showed the existence of introduced plasmid DNA inside these colonies. However, most of the cells (approx 90%) lost the resistance in the presence of 5 mg/L Zeocin during subculturing, which was consistent with the observations of both rearranged and episomal plasmid DNA existed in the cells. Nevertheless, the electroporation procedure allows introducing a gene of interest and studying its expression and function in D. salina cells.

Journal ArticleDOI
TL;DR: The boundary element-free method (BEFM) as discussed by the authors combines the BIE method for 2D elastodynamics in the Laplace-transformed domain and the improved moving least squares (IMLS) approximation.
Abstract: In this paper, we present a direct meshless method of boundary integral equation (BIE), known as the boundary element-free method (BEFM), for two-dimensional (2D) elastodynamic problems that combines the BIE method for 2D elastodynamics in the Laplace-transformed domain and the improved moving least-squares (IMLS) approximation. The formulae for the BEFM for 2D elastodynamic problems are given, and the numerical procedures are also shown. The BEFM is a direct numerical method, in which the basic unknown quantities are the real solutions of the nodal variables, and the boundary conditions can be implemented directly and easily that leads to a greater computational precision. For the purpose of demonstration, some selected numerical examples are solved using the BEFM. Copyright (c) 2005 John Wiley & Sons, Ltd.