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91.
A high-order leap-flog based non-dissipative discontinuous Galerkin timedomain method for solving Maxwell's equations is introduced and analyzed. The proposed method combines a centered approximation for the evaluation of fluxes at the interface between neighboring elements, with a Nth-order leap-frog time scheme. Moreover, the interpolation degree is defined at the element level and the mesh is refined locally in a non-conforming way resulting in arbitrary level hanging nodes. The method is proved to be stable under some CFL-like condition on the time step. The convergence of the semi-discrete approximation to Maxwell's equations is established rigorously and bounds on the global divergence error are provided. Numerical experiments with highorder elements show the potential of the method. 相似文献
92.
We studied the effect of ultrasonic activation of brine (3%) during salting on the degree of stability of colour parameters of pork with normal (NOR) and abnormal course of autolysis in the CIE Lab colour space. The mechanism of stabilisation of the colour of meat is attributed to donor–acceptor bonds of metmyoglobin (MetMb). The accumulation of excessive number of free electrons in the medium are capable of activating MetMb. This reduces the activity of meat, when the native participants of the metmyoglobin reductase system and their own antioxidant systems of meat are depleted.Based on the additive calculation of deviations (increase / decrease) by the coordinates L*, a*, b* in the CIE Lab system, and the total colour difference (ΔE) in control and experimental samples, recommendations were developed. To optimize the colour characteristics of all types of meat, both on the surface and in the thickness of the meat, the preliminary activation of a 3% brine in a low-frequency submersible ultrasonic unit is recommended. Moreover, preliminary cavitation activation of a 3% is more preferable to stabilise the colour of PSE – meat (pale, soft, exudative (watery),) brine in a flow-through installation. 相似文献
93.
用于显示乳房局部病灶组织红外热图像的伪彩色方法 总被引:1,自引:0,他引:1
通过检测人体体表每点的红外热辐射能量,可以得到反映体表温度分布的红外热图像。当乳房内部出现恶性肿瘤时,由于局部病灶组织具有异常的血运状态,会引起乳房表面病灶区域的温度显著升高。医生通过对乳房红外热图像病灶区域进行视觉分析、判断,可以实现对乳腺癌的检测。为了便于医生更好地发现这些病灶区域,本论文通过引入视觉因素,改进了传统的伪彩色显示方法,使病灶区域具有更鲜明的显示效果。这一方法的效果在47例乳腺癌病人的乳房红外热图像上得到了证实。采用这一方法对红外热图像病灶区域进行视觉分析所得到的结果,可以和采用近红外光谱等方法得到的组织血运状态进行对照比较,从而获得更为确切的诊断信息。 相似文献
94.
三维时域有限差分法计算金纳米粒子尺寸与SERS活性的关联 总被引:1,自引:0,他引:1
通过合成一系列不同粒径(16~160 nm)的金纳米粒子.观察到120~135 nm的金纳米粒子在632.8nm波长激发下具有最高的SERS活性,这与前人报道的电磁场理论及实验的结果不同.利用三维时域有限差分法对金纳米粒子的SERS活性与其尺寸以及入射光波长的关系进行模拟计算.在632.8 nm激发线下,金纳米粒子二聚体体系在粒径为110 nm左右具有最佳增强效应,其光电场耦合最强的热点处的增强因子高达109考虑到体系的平均SERS增强因子通常会比最大值低约2个数量级,计算得到的107的增强因子与实验测量值相符.同时对目前实验上尚难以合成的大尺寸的金纳米粒子进行模拟,结果表明受多极矩和大尺寸效应的影响在粒径220 nm时又出现SERS增强另一峰值.在325 nm的紫外激发线下,计算得到的增强因子仅为102. 相似文献
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99.
In atomic and many-particle physics, Green functions often occur as propagators to formally represent the (integration over the) complete spectrum of the underlying Hamiltonian. However, while these functions are very crucial to describing many second- and higher-order perturbation processes, they have hardly been considered and classified for complex atoms. Here, we show how relativistic (many-electron) Green functions can be approximated and systematically improved for few- and many-electron atoms and ions. The representation of these functions is based on classes of virtual excitations, or so-called excitation schemes, with regard to given bound-state reference configurations, and by applying a multi-configuration Dirac-Hartree-Fock expansion of all atomic states involved. A first implementation of these approximate Green functions has been realized in the framework of Jac, the Jena Atomic Calculator, and will facilitate the study of various multi-photon and/or multiple electron (emission) processes. 相似文献
100.
Chaojun Deng Haoyuan Wang Hongqiang Lan Boya Xu 《Journal of Dispersion Science and Technology》2018,39(11):1582-1587
The flow behavior in a three-phase separator with a bucket and weir was analyzed, and a theoretical equation for calculating the liquid-liquid interface level (HH) in gravity separation zone was derived. The analysis indicates that the HH increases as the flow rate and the density ratio of heavy to light liquid increase, and decreases linearly with increasing height difference between heavy and light liquid overflow weirs. The calculated HH under different operating conditions is in good agreement with the experimental. With the proposed equation, the thicknesses of heavy and light liquid layers can be calculated, and then the minimum lengths of two phase layers required for separation can be determined separately. From the minimum lengths it can be clearly indicated that the governing step of liquid-liquid separation is in heavy or light liquid layers, hence the sizing of the separator can be optimized. 相似文献