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1.
M. Kroon E. Andreasson E. Persson Jutemar V. Petersson L. Persson M. Dorn P.A.T. Olsson 《Experimental Mechanics》2018,58(1):75-86
Injection-moulding is one of the most common manufacturing processes used for polymers. In many applications, the mechanical properties of the product is of great importance. Injection-moulding of thin-walled polymer products tends to leave the polymer structure in a state where the mechanical properties are anisotropic, due to alignment of polymer chains along the melt flow direction. The anisotropic elastic-viscoplastic properties of low-density polyethylene, that has undergone an injection-moulding process, are therefore examined in the present work. Test specimens were punched out from injection-moulded plates and tested in uniaxial tension. Three in-plane material directions were investigated. Because of the small thickness of the plates, only the in-plane properties could be determined. Tensile tests with both monotonic and cyclic loading were performed, and the local strains on the surface of the test specimens were measured using image analysis. True stress vs. true strain diagrams were constructed, and the material response was evaluated using an elastic-viscoplasticity law. The components of the anisotropic compliance matrix were determined together with the direction-specific plastic hardening parameters. 相似文献
2.
基于MATLAB的异步电动机线性化控制系统的仿真 总被引:1,自引:0,他引:1
从异步电动机在同步旋转坐标系下的状态方程出发,在一定的条件下,对其系数矩阵简化.推出异步电动机的线性化控制模型.并基于该模型得出异步电动机的线性化控制系统.以给定电机为例,对该模型的有效性、响应用MATLAB进行仿真分析.验证的结果说明上述模型具有实用价值. 相似文献
3.
CHEN Zhi-hong XU Li BA Xue-qing ZENG Xian-lu 《高等学校化学研究》2006,22(3):302-307
Introduction Migrationandrecruitmentofleukocytesfromblood toinflammatorylesionsitesaresequentiallyregulated byadhesionmoleculesandtheirreceptors[1].These lectinfamilyplaysamajorroleininitiatingattachement ofneutrophilstotheactivatedendothelium.P selectin,… 相似文献
4.
5.
H. Petersson 《Acta Mathematica Hungarica》2003,100(1-2):69-81
The PDE-preserving operators O on the space of nuclearly entire functions of bounded type HNb(E) on a Banach space E are characterized. An operator is PDE-preserving when it preserves homogenous solutions to homogeneous convolution equations.
We establish a one to one correspondence between O and a set Σ of sequences of entire functionals, i.e. exponential type functions. In this way, algebraic structures on Σ,
such as ring structures, can be carried over to O and vice versa. In particular, it follows that O is a non-commutative ring (algebra) with unity with respect to composition and the convolution operators form a commutative
subring (subalgebra). We discuss range and kernel properties, for the operators in O, and characterize the projectors (onto polynomial spaces) in O by determining the corresponding elements in Σ.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
6.
7.
Ferrocene attached to the surface of a platinum electrode catalyses the electrochemical oxidation of ascorbic acid in acidic buffer solutions. The overpotential for ascorbic acid oxidation is decreased by 150 mV at pH 2.2 compared with reaction at bare platinum; and an increase in anodic current and decrease in cathodic current for the redox reaction of ferrocene occurs on addition of ascorbic acid to the solution. The ferrocene-modified electrode is useful for the voltammetric determination of ascorbic acid in natural fruit juices. The advantages result from the electrocatalytic effect and from the prevention of adsorption of inhibitory substances from solution. 相似文献
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9.
The frequency distribution of the87Rb NMR 1/2–1/2 central transition is measured in a detailed manner as a function of the temperature and the crystal orientation in the normal (N), incommensurate (IC), and commensurate (C) phases of high quality single crystals of Rb2ZnCl4 (RZC). Special emphasis is laid upon the region around the lock-in transition atT
c
. While in the N and C phases discrete lines are observed, in the IC phase a continuous distribution of frequencies is detected. In a temperature interval not exceeding 15 K aboveT
c
some centers of intensity termed C lines can be observed in the frequency distribution. They reflect the fact that in the IC phase close toT
c
several nuclei feel a local surrounding very similar to that of the low temperature C phase. For the first time in the region aroundT
c
the influence could be studied which an electric field favouring the ferroelectric C phase has on the NMR spectra. The experimental results are related to the temperature and electric field dependence of the soliton density near the lock-in transition. A general definition of the soliton density is developed whose validity is not limited to the very narrow soliton limit. The meaning of this definition is also discussed in terms of well known phenomenological theories of the three phases of RZC. The experimental NMR data can be well described by this general definition.Dedicated to Prof. Dr. H.E. Müser on the occasion of his 60th birthday 相似文献
10.
The convergence of ab initio calculations of the beryllium dimer potential is examined with several basis sets orders of perturbation theory. When the atomic pair natural orbital basis set calculations are extrapolated to the complete basis set and full CI limits, the calculated parameters: Re=2.447 Å, De=827 cm−1, ν01=212.7 cm−1, ν12=167.2 cm−1, ν23=121.5 cm−1 and ν34=77.7 cm−1 are in good agreement with the experimental parameters: Re=2.45 Å, De=839±10 cm−1, ν01=223.2 cm−1, ν12=169.7 cm−1, ν23=122.5 cm−1, and ν34=79 cm−1. 相似文献