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71.
Sansal K. Yildiz J. Fraser Forbes Biao Huang Yale Zhang Fred Wang Vit Vaculik Mike Dudzic 《Applied Mathematical Modelling》2009
Hot rolling is an essential industrial process in the production of sheet steel, a widely used product in manufacturing and construction. A finishing mill performs a set of operations in a hot strip rolling mill, and is a complex unit including many processes and control loops. Its modelling is a challenging task due to the variety of phenomena that occur within the mill, and variable transport delays. Model validation is also challenging due to a scarcity of measurements. On the other hand, a dynamic model that adequately reflects the numerous interactions between the mill units can be very useful for tasks such as high performance control design or vibration analysis. In this study, a one-dimensional model has been developed and validated against real plant data. The end use of the model is intended to be looper control analysis, but the model is kept sufficiently general so that it can be used or easily extended for other applications. 相似文献
72.
提出了一种研究折板及多面板类结构非线性弯曲行为的样条核质点法.方法包括以下步骤:(1)将折板及多面板结构模拟成不同平面上平板的集合体;(2)基于冯.卡门的大挠度理论,使用一阶剪切变形理论和样条核质点法先分析各平板的几何非线性行为;(3)将经过修正的各板的非线性刚度矩阵叠加得到整个折板结构的非线性刚度矩阵;(4)研究整个结构的几何非线性行为.由于摆脱了网格的束缚,本文方法可以避免网格扭曲引起的网格重构问题.文末通过几个算例将本文方法解与使用壳单元的ANSYS有限元解或已有文献解进行对比,验证了本文方法的收敛性和准确性. 相似文献
73.
74.
The coexisting periodic impacting motions and their multiplicity of a kind of dual component systems under harmonic excitation are analytically derived. The stability condition of a periodic impacting motion is given by analyzing the propagation of small, arbitrary perturbation from that motion. In numerical simulations, the periodic impacting motions are classified according to the system states before and after an impact. The numerical results show that there exist many types of vibro-impacts and the bifurcation of periodic vibro-impacts is not smooth. Project supported in part by National Natural Science Foundation of China under the grant 59572024 and in part by Trans-century Training Program Foundation for the Talents by the State Education Commission of China 相似文献
75.
Coiled strip can be directly produced through the twin-roll strip casting process from the melt by incorporating casting and hot rolling together into a single step. In this unique process, the strip formation from the molten metal critically relies upon the casting rolls. Thus, the design of the rolls is extremely essential. The coupled heat transfer and deformation analysis of the casting roll is carried out in a two-dimensional numerical model, using a finite element program (MARC) to examine the thermal stress and displacement. The effects of several factors such as the nickel overlay thickness on the roll surface, the casting speed, and the roll diameter on thermal characteristics are investigated. 相似文献
76.
Biyun Tang & Yongyi Lan 《偏微分方程(英文版)》2024,37(4):377-401
We investigate the Kirchhoff type elliptic problem $$Bigg(a+bint_{mathbb{R}^N}[|nabla u|^2+V(x)u^2]dxBigg)[-Delta u+V(x)u]=f(x,u), xin mathbb{R}^N,$$where both $V$ and $f$ are periodic in $x,$ 0 belongs to a spectral gap of $−∆+V.$ Undersuitable assumptions on $V$ and $f$ with more general conditions, we prove the existenceof ground state solutions and infinitely many geometrically distinct solutions. 相似文献
77.
《Integral Transforms and Special Functions》2012,23(3):193-205
In this article we examine certain formulae applying to the Riemann zeta function in the critical strip 0<Re(s)<1, and by means of the Laplace transform we demonstrate new relations between existing formulae. Müntz has proposed a formula for the Riemann zeta function in the critical strip, which involves an arbitrary function satisfying certain conditions. From this formula it is clear that a resolution of the Riemann hypothesis may hinge on a successful method for dealing with the sum-integral difference. The Euler–MacLaurin summation formula is one such device. Here, we generate new expressions for certain Laplace transforms involving the sum-integral difference. Subsequently, the formulae thus far established are generalized using an arbitrary positive number m, which makes apparent the dependence of classical analysis on formulae and results associated with the exponential function which is characterized by the particular case m=1. 相似文献
78.
Yuanyuan Cui Yaoyang Meng Yun Hu Yuqi Chen Yixian Yang Min Fang Cun Li Weiju Zhu 《中国化学会会志》2023,70(1):68-75
A novel fluorescent probe, LCH , based on dicyanisophorone and carbazole, was prepared for the visual detection of Cu2+. The probe LCH could recognize Cu2+ by fluorescence quenching in EtOH/H2O (1/4, v/v) solution, which could be easily identified under the 365 nm UV lamp, and the detection limit was as low as 0.785 μM. The recognition mechanism of probe LCH with Cu2+ was determined by combining 1H NMR titration, MS, and theoretical calculations. Practical application experiments showed that probe LCH could be used to detect Cu2+ in the test strip experiments. Cell imaging experiments showed that the probe LCH owned good cell permeability and could be applied to the imaging of Cu2+ in HepG2 cells. In addition, fluorescence colocalization experiments showed that LCH could target lipid droplets. These results indicate that the probe LCH will have a good application prospect in environmental detection and clinical medicine. 相似文献
79.
In this paper, we study the multiplicity, stability, and quantitative properties of normalized standing waves for the nonlinear Schrödinger‐Poisson equation with a harmonic potential. 相似文献
80.
Five sets of group 14 sextet cyclic unsaturated divalent species including carbenes ( 1 X ), silylenes ( 2 X ), germylenes ( 3 X ), stannylenes ( 4 X ), and plumbylenes ( 5 X ) are compared and contrasted at B3LYP/AUG‐cc‐pVTZ//B3LYP/6‐311 + G* and MP2/AUG‐cc‐pVTZ//MP2/6‐311 + G* levels of theory, where X = H, F, Cl, and Br. The scrutinized carbenes consisting of cyclonona‐3,5,7‐trienylidene ( 1 H ) and its 2,2,9,9‐tetrahalo derivatives ( 1 Cl , 1 Br ) appear as boat shaped minima except for 1 H which turns out as a boat shaped transition state for having a negative force constant. All of carbenes ( 1 H , 1 Cl , and 1 Br ) have triplet ground states except for 1 F . In contrast, all of the corresponding 2 X ‐ 5 X metallylenes appear as singlet boat shaped minima on their potential energy surfaces. Stability (estimated by ΔEs‐t, ie, energy gap between singlet [s] and triplet states) appear as a function of size and decreases by going down in group 14 column: 5 X > 4 X > 3 X > 2 X > 1 X . Exclusive of carbene set, within other four sets stability decreases by going down in group 17 column: Br > Cl > F > H. Hence, singlet 2,2,9,9‐tetrabromocyclonona‐3,5,7‐trienplumbylene, 5 Br , appears as the most stable sextet divalent with no tendency for dimerization. Comparison is extended to the structural parameters, band gap, nucleophilicity, electrophilicity, isodesmic reactions, and dimerization. 相似文献