彩色图像自微分车牌区域定位技术

车牌定位是实现智能交通系统的关键因素之一。在RGB色彩空间中,运用自微分技术实现了图像的二值化,利用水平膨胀、腐蚀技术完成了形态学处理。最后,通过由下向上扫描确定连通区域的矩形边界,结合车牌的几何尺寸,给出车牌区域的具体坐标。

On Some Fundamental Theorems in Stability Theory

This paper gives several fundamental theorems for the stability, uniform stability, asymptotic stability and uniform asymptotic stability. Those theorems allow the derivative of Lyapunov functions to be positive on certain sets,relax the restriction about the rate of change of state variable in a system to be bounded in Marachkov's theorem and extend the related results in [4—7].

Use of Solid SMEDDS in Delivery of Carvedilol

Aim A new solid SMEDDS (self-microemulsifying drug delivery system) capsule has been developed to increase the solubility and dissolution rate. Methods The solubilities of carvedilol in various bases were investigated. Ternary phase diagrams were used to evaluate the self-emulsification and self-microemulsfication domains. The particle size distribution and ζ-potential were determined. The mean diameter of the three formulae decreased with an increase of Lutrol F68. Results The in vitro dissolution rate of ...

Positive Periodic Solutions for Nonautonomous Differential Equations with Delay

By utilizing a fixed point theorem on cone, some new results on the existence ofpositive periodic solutions for nonautonomous differential equations with delay are derived.

Classical Completely Integrable System Generated through Nonlinearization of an Eigenvalue Problem

Under the Bargmann constrained condition, the spatial part of a new Lax pair of the higher order MkdV equation is nonlinearized to be a completely integrable system (R2N,dp^dq, H0=1/2F0)(F0= (^q,p) + (^p,p) + (p,q)2). While the nonlinearization of the time part leads to its N-involutive system (Fm).

Negative Differential Resistance and Spin-Filtering Effects in Zigzag Graphene Nanoribbons with Nitrogen-Vacancy Defects

We explore the electronic and transport properties of zigzag graphene nanoribbons （GNRs） with nitrogen-vacancy defects by performing fully self-consistent spin-polarized density functional theory calculations combined with non-equilibrium Green＇s function technique. We observe robust negative di erential resistance （NDR） effect in all examined molecular junctions. Through analyzing the calculated electronic structures and the bias-dependent transmission coefficients, we find that the narrow density of states of electrodes and the bias-dependent effective coupling between the central molecular orbitals and the electrode subbands are responsible for the observed NDR phenomenon. In addition, the obvious di erence of the transmission spectra of two spin channels is observed in some bias ranges, which leads to the near perfect spin-filtering effect. These theoretical findings imply that GNRs with nitrogenvacancy defects hold great potential for building molecular devices.

π-Electron-Assisted Relaxation of Spin Excited States in Cobalt Phthalocyanine Molecules on Au（111） Surface

We present our investigation on the spin relaxation of cobalt phthalocyanine （CoPc） films on Au（111） （CoPc/Au（111）） surface using scanning tunneling microscopy and spectroscopy. The spin relaxation time derived from the linewidth of spin-flip inelastic electron tunneling spectroscopy is quantitatively analyzed according to the Korringa-like formula. We find that although this regime of the spin relaxation time calculation by just considering the exchange interaction between itinerant conduction electrons and localized d-shells （s-d exchange interaction） can successfully reproduce the experimental value of the adsorbed magnetic atom, it fails in our case of CoPc/Au（111）. Instead, we can obtain the relaxation time that is in good agreement with the experimental result by considering the fact that the 7c electrons in CoPc molecules are spin polarized, where the spin polarized 7c electrons extended at the Pc macrocycle may also scatter the conduction electrons in addition to the localized d spins. Our analyses indicate that the scattering by the π electrons provides an efficient spin relaxation channel in addition to the s-d interaction and thus leads to much short relaxation time in such a kind of molecular system on a metal substrate.

Observer-based Iterative and Repetitive Learning Control for a Class of Nonlinear Systems

In this paper, both output-feedback iterative learning control(ILC) and repetitive learning control(RLC) schemes are proposed for trajectory tracking of nonlinear systems with state-dependent time-varying uncertainties. An iterative learning controller, together with a state observer and a fully-saturated learning mechanism, through Lyapunov-like synthesis, is designed to deal with time-varying parametric uncertainties. The estimations for outputs, instead of system outputs themselves, are applied to form the error equation, which helps to establish convergence of the system outputs to the desired ones. This method is then extended to repetitive learning controller design. The boundedness of all the signals in the closed-loop is guaranteed and asymptotic convergence of both the state estimation error and the tracking error is established in both cases of ILC and RLC. Numerical results are presented to verify the effectiveness of the proposed methods.

Low-Storage Runge-Kutta Method for Simulating Time-Dependent Quantum Dynamics

A wide range of quantum systems are time-invariant and the corresponding dynamics is dic- tated by linear differential equations with constant coefficients. Although simple in math- ematical concept, the integration of these equations is usually complicated in practice for complex systems, where both the computational time and the memory storage become limit- ing factors. For this reason, low-storage Runge-Kutta methods become increasingly popular for the time integration. This work suggests a series of s-stage sth-order explicit Runge- Kutta methods specific for autonomous linear equations, which only requires two times of the memory storage for the state vector. We also introduce a 13-stage eighth-order scheme for autonomous linear equations, which has optimized stability region and is reduced to a fifth-order method for general equations. These methods exhibit significant performance improvements over the previous general-purpose low-stage schemes. As an example, we ap- ply the integrator to simulate the non-Markovian exciton dynamics in a 15-site linear chain consisting of perylene-bisimide derivatives.

Automatic Analysis Reporting for Hydro-Chemical Data Using Updated DurovPwin Program

Graphical representation of groundwater major dissolved constituents greatly help researchers in understanding the hydro-chemical evolution, grouping and areal distribution. Durov diagram is one of the most widely used technique but it requires a lot of tedious calculations. The DurovPlot program, which is used to plot the expanded Durov diagram as a graphical representation of groundwater major dissolved constituents is working on Disk Operating System （DOS） environment. Therefore, the need of a new program working under windows is a must. The program termed as DurovPwinis developed using Microsoft visual studio 2010. The DurovPwin program not only calculates the Durov coordinates and plot it, but also plots the total dissolved solids （TDS） on logarithmic scale and the measure of the activity of hydrogen ion （pH） of the given samples. The updated DurovPwin adds many features such as interface with Microsoft Office package （Word and Excel） to read the input chemical elements and automatically write result interpretation report. The user facility to group wells based on data features is added and the selection of the electric balance tolerance （10% as default） value is given. Another feature of the modified DurovPwinis has the ability to do useful X-Y plot for different hydro-chemical parameters to assist in data interpretation. The sodium adsorption ratio （SAR） is also calculated and written in the final report. Also, in the present study, the usability of the new version of DurovPwin program has been tested on the chemical data from 59 groundwater samples collected from A1-Jawf area, Saudi Arabia. The collected water samples were mainly from the Secondary-Tertiary-Quaternary （STQ） aquifer and some from Tawil and Jaufaquifers. The grouping of the major ions in the three aquifers have been displayed and presented using the DurovPwin program. The TDS values of Tawil aquifer ranges from 257.9 to 822.3 （2.4115 to 2.915） and for Jawf aquifer from 494.4 to 1,070 （2.6941 to 3.0294） and for STQ aquifer ranges from 399.5 to 9,861.8 （2.6015 to 3.994）. The pH for the three aquifers ranges from 7 to 7.9, 7.6 to 7.8 and 7.2 to 8.3, respectively.

Uncertainty Calculation of Roundness Assessment by Automatic Differentiation in Coordinate Metrology

Reomtly, Coordinate bieasuring Machines （CMMs） are widely used to measure roundness errors. Roundness is calculated from a large number of points collected from the profiles of the parts. According to the Guide to the Expression of Uncertainty in Measta- meat （GUM）, all measurement results must have a stated uncertainty associated the titan. However, no CMMs give the uncertainty value of the roundness, because no suitable measrement uncertainty calculation procedure exists. In the case of roundness raeasurement in coordinate metrology, this paper suggests the algorithms for the calculation of the measurement uncertainty of the roudness deviation based on the two mainly used association criteria, LSC and MZC. The calculation of the sensitivity coefficients for the uncertainty calculatiion can be done by autnatic differentiation, in order to avoid introducing additional emars by the traditional difference quotient approxima- tions. The proposed methods are exact and need input data only as the nrasured coordinates of the data points and their associated un- certainties.

Effects of Transverse Field on Internal Energy and Specific Heat of a Molecular-Based Materials

The molecular-based magnetic materials AFe11 Fe111（C2O4）3 have a honeycomb structure in which FeII （S = 2） and FeIH （S= 5/2） occupy sites alternately. They can be described as mixed spin-2 and spin-5/2 Ising model with ferrimagnetic interlayer coupling. The influences of the transverse field on the internal energy and the specific heat of the molecalar-based magnetic system have been studied numerically by using the effective-field theory with self-spin correlations and the differential operator technique.

A Possible Minimum Toy Model with Negative Differential Capacitance for Self-sustained Current Oscillation

We generalize a simple model for superlattices to include the effect of differential capacitance. It is shown that the model always has a stable steady-state solution （SSS） if all differential capacitances are positive. On the other hand, when negative differential capacitance is included, the model can have no stable SSS and be in a self-sustained current oscillation behavior. Therefore, we find a possible minimum toy model with both negative differential resistance and negative differential capacitance which can include the phenomena of both self-sustained current oscillation and I-V oscillation of stable SSSs.

Vibration mechanism analysis and algorithm optimization of contactor contact system

In order to solve the problem of vibration bounce caused by the contact between moving and stationary contacts in the process of switching on,two-degree-of-freedom motion differential equation of the contact system is established.Genetic algorithm is used to optimize the pull in process of AC contactor.The whole process of contact bounce was observed and analyzed by high-speed photography experiment.The theory and experimental results were very similar.The iron core has collided before the contact is separated,which further aggravates the contact bounce.When the iron core bounces collided again,the bounce of the contact was not affected.During the operation of the contactor,the movement of the moving iron core will cause slight vibration of the system.The contact bounce time and the maximum amplitude are reduced.The research results provide a theoretical basis for further control and reduction of contact bounce.

Vector Product and an Integrable Dynamical System

We study an autonomous system of first order ordinary differential equations based on the vector product. We show that the system is completely integrable by constructing the first integrals.The connection with Nambu mechanics is established.The extension to higher dimensions is also discussed.

PREPARATION OF POLYELECTROLYTE MULTILAYER COATED MICROBUBBLES FOR USE AS ULTRASOUND CONTRAST AGENT

Objeelive To prepare and characterize polyelectrolyte multilayer film coated microbubbles for use as ultrasound contrast agent （UCA） and evaluate its effects in ultrasonic imaging on normal rabbit＇s fiver parenchyma. Methods Perfluorocarbon （PFC）-containing microbubbles （ST68-PFC） were prepared by sonication based on suffactant （ Span 60 and Tween 80）. Subsequently, the resulting ST68-PFC microbubbles were coated using oppositely charged polyelectrolytes by microbubble-templated layer-by-layer self-assembly technique via electrostatic interaction. The enhancement effects in ultrasonic imaging on normal rabbit＇s liver parenchyma were assessed. Results The obtained microbubbles exhibited a narrow size distribution. The polyelectrolytes were successfully assembled onto the surface of ST68-PFC microbubbles. In vivo experiment showed that polyelectrolyte multilayer film coated UCA effectively enhanced the imaging of rabbit＇s liver parenchyma. Conclusions The novel microbubbles UCA coated with polyelectrolyte multilayer, when enabled more function, has no obvious difference in enhancement effects compared with the pre-modified microbubbles. The polymers with chemically active groups （ such as amino group and carboxyl group） can be used as the outermost layer for attachment of targeting ligands onto microbubbles, allowing selective targeting of the microbubbles to combine with desired sites.

Existence of positive solutions in a delay logistic difference equation

The author studied the existence of positive solutions of the delay logistic difference equation Δ y n=p ny n(1-y τ(n) ), n =0,1,2,.... where { p n } is a sequence of positive real numbers, { τ(n) } is a nondecreasing sequence of integers, τ(n)<n and lim n →∞ τ(n) =∞. A sufficient condition for the existence of positive solutions of the equation was given.

Proton Elastic Scattering from ^14Be and Halo Effects

The elastic scattering of p-^14Be system at Elab = 200 MeV is evaluated within the relativistic impulse approximation. We discuss the effects of the halo neutrons on the three observables of the elastic scattering system, such as differential cross section dσ/ dΩ, analyzing power Ay and spin rotation Q. The results of the three observables of the elastic scattering of p-^14Be system are compared with those of p-^12C and p-^16O systems at the same energy as E1ab = 200 MeV. We have found that in the small angular region the Ay and Q, as well as dσ/dΩ, are quite sensitive to the nucleon density distributions on the surface of the target nucleus and offer some unique behaviors of halo nuclei.

Uniform Convergence Analysis of Finite Difference Scheme for Singularly Perturbed Delay Differential Equation on an Adaptively Generated Grid

Adaptive grid methods are established as valuable computational technique in approximating effectively the solutions of problems with boundary or interior layers. In this paper,we present the analysis of an upwind scheme for singularly perturbed differential-difference equation on a grid which is formed by equidistributing arc-length monitor function.It is shown that the discrete solution obtained converges uniformly with respect to the perturbation parameter.Numerical experiments illustrate in practice the result of convergence proved theoretically.

Clustering-driven watershed adaptive segmentation of bubble image

In order to extract froth morphological feature,a bubble image adaptive segmentation method was proposed.Considering the image's low contrast and weak froth edges,froth image was coarsely segmented by using fuzzy c means(FCM) algorithm. Through the attributes of size and shape pattern spectrum,the optimal morphological structuring element was determined.According to the optimal parameters,some image noises were removed with an improved area opening and closing by reconstruction operation,which consist of image regional markers,and the bubbles were finely separated from each other by watershed transform.The experimental results show that the structural element can be determined adaptively by shape and size pattern spectrum,and the froth image is segmented accurately.Compared with other froth image segmentation method,the proposed method achieves much high accuracy,based on which,the bubble size and shape features are extracted effectively.