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21.
继承异常用来描述在并发面向对象语言中继承与并发的冲突.对继承异常做了系统的分析,给出一种新的分类.提出在一并发对象中将同步部分与顺序部分分离,生成两个对象,通过将同步代码放入一单独对象,将继承过程分为顺序部分和同步部分,这种分离大大地减少了继承异常的发生. 相似文献
22.
人群异常事件检测是智能视频监控领域的重要研究内容, 文章提出了一种融合速度强度熵VMME与纹理特征的人群异常行为检测算法. 该算法采用LBPCM算法提取图像纹理特征, 在视频帧计算光流基础上, 获得特征点速度强度图, 并以其熵VMME作为场景运动特征, 将场景纹理特征和运动特征送入支持向量机训练分类. 实验表明, 新算法可实现对人群异常行为的检测, 且有较高准确率. 相似文献
23.
A. Cig J. Ma
ka M. Mair G. Gritzner G. Plesch V. Zrubec 《Physica C: Superconductivity and its Applications》1999,320(3-4):267-276
The effects of the thallium and mercury content x on the as-sintered and post annealed samples of MxPb0.4Sr1.6Ba0.4Ca2Cu3O8+δ {M: Tl (0.32≤x≤0.74) or Hg (0.18≤x≤0.68)} have been studied by magnetization and transport measurements. For Tl-1223 we have found the optimum Tl doping level to be x=0.53 regarding the grain properties, the content of superconducting phase, the first penetration field Hplwl, the transport (Jctr), magnetic intergrain (JcM) and intragrain (Jcg) critical current densities. The critical temperature Tc of the as-sintered Tl-1223 sample decreased with increasing Tl content. Post-annealing in oxygen improved the Tc for Tl contents of x≥0.53 and had generally positive effects on the critical current densities. The intergrain properties of the Hg-1223 samples were much worse than those of the Tl-based superconductors. 相似文献
24.
Quantitative and qualitative assessment of articular cartilage in the goat knee with magnetization transfer imaging 总被引:7,自引:0,他引:7
Didier Laurent James Wasvary Jianyun Yin Markus Rudin Theodore C. Pellas Elizabeth OByrne 《Magnetic resonance imaging》2001,19(10):377-1286
We investigated the role of collagen in the magnetization transfer (MT) effect in contrast to other macromolecules. By means of phantoms made of collagen, chondroitin sulfate (CS) and albumin, MR parameters have been optimized in order to reduce the acquisition time and improve the sensitivity, as well as to minimize the contributions from CS and albumin to the MT induced signal attenuation. The same method was used to study cartilage ex vivo (bovine articular and nasal cartilage plugs) and in vivo (goat knee femoral chondyle). In phantom samples, the MT signal attenuation depended on the collagen concentration while contributions from the other macromolecules were found to be minimal. In average, analysis of MT images revealed a 25%, 35% and 30% signal attenuation in 10% w/v type I collagen gels, cartilage plugs, and cartilage from the weight-bearing areas of the goat knee, respectively. Biochemical data revealed that treatment of cartilage plugs with bacterial collagenase led to collagen depletion and correspondingly to a decrease of the MT response. In contrast, trypsin-induced proteoglycan loss in cartilage plugs did not alter the MT effect. A significant correlation was observed between the collagen content in these plugs and their respective MT ratios and the rate constant k for the exchange process bound versus free water. Finally, data obtained from in vivo MT measurement of the goat knee demonstrated that intra-articular injection of papain might not only cause degradation of proteoglycans but also a change in collagen integrity in a dose-dependent manner. We conclude that in vivo measurement of MT ratios gives quantitative and qualitative information on the collagen status and may be applied for the routine evaluation of normal and abnormal articular cartilage. 相似文献
25.
R. Lavín C. Gallardo J.L. Palma J. Escrig J.C. Denardin 《Journal of magnetism and magnetic materials》2012
The angular dependence of the coercivity and remanence of ordered hexagonal arrays of Co nanowires prepared using anodic aluminum oxide templates was investigated. The experimental evolution of coercivity as a function of the angle, in which the external field is applied, is interpreted considering micromagnetic simulations. Depending on the angle between the axis of the wire and the applied magnetic field direction our results show that the magnetization reversal mode changes from vortex to a transverse domain wall. Besides, we observed that the dipolar interactions cause a reduction in coercive fields, mainly in the direction of easy magnetization of the nanowires. Good agreement between numerical and experimental data is obtained. 相似文献
26.
Huang T. Zeng D. Petit L. O’Brien D. Read E.R. Lewis R.P. Cowburn 《Journal of magnetism and magnetic materials》2010,322(14):2010-2014
We present here a numerical study of the magnetostatic charge distribution of transverse Néel type domain wall in permalloy nanowires. The calculations indicate that not only is the distribution highly non-uniform within a given transverse wall but it also varies dramatically with respect to the wire width. The implications of this for magnetostatic domain wall pinning are analyzed by considering the stray field interaction between a wall and another extended magnetic body for a particular domain wall chirality, where two distinct depinning mechanisms are observed depending on the wire width. 相似文献
27.
O. Idigoras 《Journal of magnetism and magnetic materials》2010,322(20):L57
We have studied the magnetization reversal of uniaxial Co(1 0 1 0) films as a function of the applied field orientation by means of magneto-optical Kerr effect microscopy. Hereby, we find that while stable intermediate domain states exist for most field directions, their occurrence is suppressed for field orientations along the easy axis of magnetization. To facilitate this study, we have developed a data extraction methodology that allows for the quantitative analysis and compact display of entire magnetization distribution field-sequences in a single picture. It furthermore allows for the automated data analysis to unambiguously distinguish magnetization rotation processes from field-induced domain formation. 相似文献
28.
Control on the size of copper oxide (CuO) in the nano range is a highly motivating approach to study its multifunctional nature. The present investigation reports a sol-gel derived Ni doped CuO nanoparticles (Cu1-xNixO). Rietveld refinement of the XRD spectra confirms the formation of single monoclinic phase of Cu1-xNixO nanoparticles having crystallite size within the range of 19–21 nm. Raman spectra show the presence of characteristics Raman active modes and vibrational bands in the Cu1-xNixO samples that corroborate the monoclinic phase of the samples as revealed by refinement of XRD data. The estimated band gap of pure CuO is found to be ∼1.43 eV, which decreases with the increase of dopant concentration into CuO matrix. This result is in line with estimated crystallite size. Magnetization curves confirm the weak ferromagnetic nature of Cu1-xNixO nanoparticles which reveal the DMS phase. This weak magnetic nature may be induced in the samples due to the exchange interaction between the localized magnetic d-spins of Ni ions and carriers (holes or electrons) from the valence band of pristine CuO lattice. Replacement of Cu+2 by Ni+2 ions into the host CuO lattice induces the magnetization. The quantified value of squareness ratio (S < 0.5) confirms the inter-grain magnetic interactions in the Cu1-xNixO nanoparticles which is also the reason of weak induced magnetization. 相似文献
29.
The effective action of chiral QCD2 was studied in
two-dimensional non-commutative space-time by using path integral
approach. It is shown that vector boson has a mass generation and
the effective Lagrangian contains a term corresponding to a
Wess-Zumino-Witten-like term. 相似文献
30.
Vibhav Pandey R.P. Aloysius V.P.S. Awana R.K. Kotnala 《Journal of magnetism and magnetic materials》2009,321(14):2239-2244
The structural magnetic and magneto-transport properties of double perovskite system Ba2−xSrxFeMoO6 (0?x?1.0) prepared in bulk polycrystalline form are reported in this paper. X-ray diffraction analysis showed that samples are single phase and the lattice constants decreases with increase in the Sr content. The degree of Fe-Mo ordering has been found decreasing in the series with an increase in the Sr content. Parent compound Ba2FeMoO6 exhibits saturation magnetic moment value of 3.54 μB/f.u. at 85 K in a magnetic field of 6000 Oe. Temperature dependence of resistivity shows metallic behavior for all the samples. The magneto-resistance (MR) of the compound with x=0.4 is higher than that of the other samples. At room temperature this system shows a saturation magnetization value of 1.73 μB/f.u. and MR value of 7.08% (1 T). The observed variations in the structural and magnetic properties are attributed to the change of chemical pressure due to the substitution of Sr in place of Ba. The effect of antisite disorder (ASD) defects on magneto-transport properties is studied in more detail. 相似文献