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1.
Szasz-type operators can be constructed by a Poisson process. The purpose of this paper is to derive the converse result in connection with Szasz-type operators by Steckin-Marchaud-type inequalities and new Ditzian modulus of continuity. The degree of approximation on deterministic signals is also given.  相似文献   

2.
As an important type of polynomial approximation, approximation of functions by Bernstein operators is an important topic in approximation theory and computational theory. This paper gives global and pointwise estimates for weighted approximation of functions with singularities by Bernstein operators. The main results are the Jackson's estimates of functions f∈ (Wwλ)2 andre Cw, which extends the result of (Della Vecchia et al., 2004).  相似文献   

3.
INTRODUCTION One of the main advantages of chemical groutsis easy control of gel time (Mollamahmutoglu andLittlejohn, 1996; ?nupárek and Soucek, 2000).Calcium acrylate is a chemical grout usually used ingeotechnical engineering (Zelanko and Karfakis,1997), and is a water-soluble monomer that po-lymerizes in an aqueous solution. The rate of po-lymerization is controlled by the concentration ofcatalyst and activator. The polymerization of cal-cium acrylate is free radical chain pol…  相似文献   

4.
The relation between composition operators on the Dirichlet spaces in the open unit disk and derivative weighted composition operators on the Bergman spaces in the open unit disk is investigated firstly,and for a combination of several derivative weighted composition operators which acts on classic Bergman space,the lower bound of its essential norm is estimated in terms of the boundary data of the symbols of d-composition operators.Some similar results about composition operators on the Dirichlet space are also presented.A necessary condition is given to determine the compactness of the combination of several derivative weighted composition operators on Bergman spaces.  相似文献   

5.
The maximally holomorphic functions of a bounded linear operator is introduced and applied to representthe spectrum and characterize the single--valued extension property. The well known results of quasi--nilpo-tent equivalent operators follow easily from the relation of their maximally holomorphie functions.  相似文献   

6.
对局部有界函数f的积分型Szász-Bézier算子的逼近阶进行估计.在Zuo和Zeng关于积分型Szász-Bézier算子的逼近阶估计公式研究的基础上,得到更精确估计公式.  相似文献   

7.
The optimum design for flexible pavement structure is studied by using themethod of mathematical programming.The mathematical model is founded on the basisof“Design Code of Highway Flexible Pavement”issued by the Ministry of Communica-tions of China.The objective function is the cost of pavement structure.The optimal solu-tions of the mathematical model were searched successfully by flexiplex tolerance method.The relevant program has been developed on DPS-8 and IBM-PC computers.And thecalculated results show good convergence and accuracy for engineering applications.  相似文献   

8.
郑婷 《海外英语》2011,(6):385-386
The recent two decades have seen a great increase of Original Equipment Manufacturing ("OEM") business in China. OEM products are used exclusively for export purpose and retailed in foreign markets labelled as the purchasing company’s brand. However, whether the use of a trade mark in this circumstance constitutes the "use" in Trade Mark Law and what evidence is needed to justify the "use" in any continuous three-year period have been the focal points of debate regarding the appropriate compass of Trade Mark Law. Looming behind the uncertainty of the legal term -"use" and inconsistent standards adopted by administrative authorities and courts are unidentified risks to be taken by OEM operators.  相似文献   

9.
给出了Szász-Mirakjan算子及导数的一致逼近定理.  相似文献   

10.
Two-photon Jaynes-Cummimgs model is generalized to the case of Kerr medium in this paper,The field and atom are prepared initially in two-photon superposition state and ground state respectively.Nonlinear coefficient affects the dynamic behaviors of the field and atom.Evolutions of the squeezing for the operators of field and atom and the quantum inversion are discussed.In particular,the higher-order squeezing for atomic dipole and the effects of nonlinearity on it,which have not been studied by other authors,are investigated,Increasing the nonlinear coefficient will decrease the squeezing depth of atomic dipole.  相似文献   

11.
主要研究Szász-Mirakjan算子线性组合的饱和性。在一定条件的假设下,当r=2时,SzászMirakjan算子线性组合的饱和性可由光滑模刻画。  相似文献   

12.
For a strip transmission line shielded by rectangular walls,the Green‘s function is helpful to construct the variation expression of the electrostatic energy.Thomson theorem is employed to determine the charge distribution on the strip.The electrostatic force on each side of the rectangular shield wall is achieved by using the principle of virtual work.The results is easy to be obtained by computerized calculation.  相似文献   

13.
The two-level atom is described by Pauli sign and environment is described by infinite harmonic particle thermal reservoir.We have studied the entanglement of two-level atoms which are put in the strongly thermal radiation field.The two-level atoms' reducible density rectangular array is obtained.We discuss the properties of entanglement by virtue of concurrence.It is shown that the two two-level atoms initially situated in different coherent superposition states,entanglement of atoms have obvious dissimilarity.  相似文献   

14.
The follow-up application of underwater wireless sensor network is influenced by accuracy of self-localization of nodes. The self-localization of nodes is discussed in this paper. First of all, nodes of underwater wireless sensor network are classified into several levels according to the accuracy of position of nodes and the levels are from the first to the fifth in accordance with accuracy of nodes from high to low respectively. Secondly, the level of anchor nodes can be known by those unknown nodes from the information given by the anchor nodes themselves, At the same time the unknown nodes are able to be located in the area controlled by the first level of anchor nodes that are as the aggregation. Then the positioning algorithm is designed correspondingly in accordance with the accuracy level of nodes. Finally, the positioning algorithm is simulated and analyzed. The result shows that the unknown nodes can be located effectively by hierarchical control.  相似文献   

15.
A precise micro-location compliant stage with elastics-supported system is enmployed for investigations.The general motion of stage supported by elastic structure is described.The analyses of forward displecement and inverse displacement of stage are formulated.The study of input-output behavior of compliant mechanisms actually belongs to a stress-strain field problem.By using finite element analysis.the compliance coefficients of the stage supported by ring are calculated.Finally,a case is inverstigated to exemplity these formulae.  相似文献   

16.
The influence of small organics on the adsorption characteristics of activated carbon produced from industrial pyrolytic tire char(APTC)for malachite green(MG) was investigated by a batch method. Phenol was chosen as the representative of small organics. The effects of phenol on adsorption equilibrium, kinetics and thermodynamics were studied systematically. The results indicate that APTC is a potential adsorbent for MG. The presence of phenol decreases the adsorption capacity of APTC for MG, but improves the rate of adsorption, while the adsorption characteristics, such as equilibrium, kinetics and thermodynamics are not affected by phenol. The adsorption equilibrium data follow Langmuir isotherm and the kinetic data are well described by the pseudo-second-order kinetic model. The adsorption process follows intra-particle diffusion model and the adsorption rate is determined by more than one process. Thermodynamic study shows that the adsorption is an endothermic and spontaneous physisorption process.  相似文献   

17.
One dimensional electron density perturbation is derived by using the cold fluid equation,Possion‘s equation and the continuity equation.The perturbation is generated by a driving laser pulse propagating through a plasma,The upshifting of the frequency of a trailing pulse induced by density perturbation is studide by using optical metric.The results show that it is possible that the photon will gain energy from wht wakefield when assuming photon‘s number to be conserved.i.e..,thd photon will be accelerated.  相似文献   

18.
The amorphous Fe67.5 alloy particles have been prepared by mechanical alloying(MA) process of elemental powders.The crystallization is observed at temperature around 405℃ by means of differential thermal analyzer,It is found that the coercivity Hc and the effective magnetic anisotropy value of amorphous phase are not far from that of crystal phase.The magnetization behavior of amorphous and nanocrystalline samples prepared by mechanical alloying and milling process are quite similar,they obey 1/H law at middle-high field and 1/H^2 at higher field.The 1/H field dependence is attributed to a large number of dislocations created during MA process.The studies on the 1/H^2 field dependence reveals that magnetization of Fe-Ni ultrafine particles are governed predominantly by internal stress fields induced by MA process.  相似文献   

19.
The methodology of 5-axis cutter selection to avert collision for free-form surface machining by flat-end cutters is presented.The combination of different cutters is adopt aiming at short machining time and high precision.The optimal small cutter is determined based on the geometric information of the points where a cutter most probably collide with the machined surface.Several larger cutters are slected to machine the surface in order to find the interference-free area.The difference of machining time for this area between the optimal small cutter and the large cutters is calculated.The functional relationship between the machining time and the radius of a cutter is established,by which the optimal number of cutters is obtained.The combination of cutters,which possesses the minimum overall machining time,is selected as the optimal cutter sizes.A case study has demonstrated the validity of the proposed methodology and algorithms.  相似文献   

20.
The transmission performance of cycloid ball planetary transmission (CBPT) is affected by cycloid tooth undercutting directly, and the design of CBPT can be optimized by the non-undercutting condition. Firstly, the theoretical equation of cycloid tooth is given, and the curvature radius of cycloid tooth profile is derived. Secondly, according to the relationship between the curvature radius and the distribution circle of balls, the non-undercutting condition of cycloid tooth profile is established, and the non-undercutting critical condition is deduced. Finally, the validity of the non-undercutting critical condition is verified by simulation. The result shows that the non-undercutting critical condition can be used to optimize the design of CBPT  相似文献   

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