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71.
分析了弹性区域中应力传播的波动方程,说明该应力传播过程可以使用线性系统模型进行描述。根据系统辨识领域的脉冲响应方法,建立了应力测点的脉冲序列与源函数和响应序列之间的关系。在此基础上,建立了各测点间应力序列之间的关联响应模型,给出了采用神经网络的自适应优化方法求解关联参数的方法,并采用某次黄土介质中化学爆炸的实验数据进行了验证。将该模型用于测点数据的预测,预测值和实测值之间的误差很小。这表明,各测点间存在与测量数据无关的客观联系,仅由实验中爆炸源、测点位置和地介质力学参数分布等所决定。 相似文献
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74.
Man Duan Dongmei Han Nan Gao Wenbin Shen Kun Chang Xinyu Wang Jianshi Du 《Molecules (Basel, Switzerland)》2022,27(5)
Porous organic polymers have an open architecture, excellent stability, and tunable structural components, revealing great application potential in the field of fluorescence imaging, but this part of the research is still in its infancy. In this study, we aimed to tailor the physical and chemical characteristics of indocyanine green using sulfonic acid groups and conjugated fragments, and prepared amino-grafted porous polymers. The resulting material had excellent solvent and thermal stability, and possessed a relatively large pore structure with a size of 3.4 nm. Based on the synergistic effect of electrostatic bonding and π–π interactions, the fluorescent chromogenic agent, indocyanine green, was tightly incorporated into the pore cavity of POP solids through a one-step immersion method. Accordingly, the fluorescent chromogenic POP demonstrated excellent imaging capabilities in biological experiments. This preparation of fluorescent chromogenic porous organic polymer illustrates a promising application of POP-based solids in both fluorescence imaging and biomedicine applications. 相似文献
75.
We give a geometric analysis of relaxation oscillations and canard cycles in a singularly perturbed predator–prey system of Holling and Leslie types. We discuss how the canard cycles are found near the Hopf bifurcation points. The transition from small Hopf-type cycles to large relaxation cycles is also discussed. Moreover, we outline one possibility for the global dynamics. Numerical simulations are also carried out to verify the theoretical results. 相似文献
76.
Daniel Carando Ignacio Zalduendo 《Proceedings of the American Mathematical Society》1999,127(1):241-250
We study the problem of extendibility of polynomials over Banach spaces: when can a polynomial defined over a Banach space be extended to a polynomial over any larger Banach space? To this end, we identify all spaces of polynomials as the topological duals of a space spanned by evaluations, with Hausdorff locally convex topologies. We prove that all integral polynomials over a Banach space are extendible. Finally, we study the Aron-Berner extension of integral polynomials, and give an equivalence for non-containment of .
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78.
On the Decay of Turbulence in the 20-Liter Explosion Sphere 总被引:1,自引:0,他引:1
The transient flow field in the standard 20-liter explosion sphere was investigated by means of laser Doppler anemometry.
Velocities were measured at various locations within the flow field, and this information was used to quantify the transient
behavior of the root-mean-square of the velocity fluctuations and to investigate the spatial homogeneity and the directional
isotropy of the turbulence. The investigation involved the transient flow fields generated by the three most widely used dust
dispersion systems, namely, the Perforated Dispersion Ring, the Rebound Nozzle, and the Dahoe Nozzle. With all three dispersion
dust devices, the decay of turbulence could be correlated by a decay law of the form
It was found that no formal cube-root-law agreement exists between the 20-liter explosion sphere and the 1-m3 vessel. The results of this work also call into question the widely held belief that the cube-root-law is a valid scaling
relationship between dust explosion severities measured in laboratory test vessels and the severity of industrial dust explosions.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
79.
J. Extremera 《Journal of Functional Analysis》2003,197(1):212-227
Let G be a compact group. If the trivial representation of G is not weakly contained in the left regular representation of G on L02(G) and X is either Lp(G) for 1<p?∞ or C(G), then we show that every complete norm |·| on X that makes translations from (X,|·|) into itself continuous is equivalent to ||·||p or ||·||∞ respectively. If 1<p?∞ and every left invariant linear functional on Lp(G) is a constant multiple of the Haar integral, then we show that every complete norm |·| on Lp(G) that makes translations from (Lp(G),|·|) into itself continuous and that makes the map t?Lt from G into bounded is equivalent to ||·||p. 相似文献
80.
地质环境中微量元素与人类心血管疾病 总被引:5,自引:0,他引:5
徐承水 《广东微量元素科学》2000,7(4):22-24
介绍了地质环境中三种微量元素硒,铜,钼的分布特点及与人类心血管疾病的关系。 相似文献