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591.
基于对p-1维输出空间进行剖分的思想,提出了一种求解线性比式和问题的分枝定界算法.通过一种两阶段转换方法得到原问题的一个等价问题,该问题的非凸性主要体现在新增加的p-1个非线性等式约束上.利用双线性函数的凹凸包络对这些非线性约束进行凸化,这就为等价问题构造了凸松弛子问题.将凸松弛子问题中的冗余约束去掉并进行等价转换,从而获得了一个比凸松弛子问题规模更小、约束更少的线性规划问题.证明了算法的理论收敛性和计算复杂性.数值实验表明该算法是有效可行的. 相似文献
592.
研究了一维六方准晶双材料中圆孔边不对称共线界面裂纹的反平面问题。利用Stroh公式和复变函数方法得到了声子场和相位子场耦合作用下的复势函数,给出了裂纹尖端应力强度因子和能量释放率的解析表达式。通过数值算例,讨论了圆孔半径和裂纹长度对应力强度因子的影响,以及耦合系数、声子场应力和相位子场应力对能量释放率的影响。结果表明:当圆孔半径不变时,应力强度因子随右裂纹长度的增大趋向稳定值。当相位子场应力取一定值时,能量释放率达到最小值,说明特定的相位子场应力可以抑制裂纹的扩展。 相似文献
593.
594.
Xiao-Qiang Dong Yue-Ting Zhou Lian-Ming Wang Sheng-Hu Ding Jun-Boum Park 《Archive of Applied Mechanics (Ingenieur Archiv)》2014,84(5):639-656
An exact contact analysis of two collinear stamps over the surface of orthotropic materials is performed. Eigenvalue analyses related to the governing equations are conducted, and real fundamental solutions are obtained for each eigenvalue distribution. Using Fourier sine or cosine transforms, a singular integral equation of Cauchy type is obtained. In particular, the exact solution of the reduced singular integral equation is obtained in the case of two collinear flat or cylindrical stamps. Explicit expressions for various stresses are obtained in terms of elementary functions. Numerical results are presented, and interesting observations are found. For two collinear flat stamps, detailed calculations are provided to show influences of distance between two flat stamps on the contact stress and in-plane stress. For a cylindrical stamp, influences of distance between two cylindrical stamps, mechanical loading P, and the cylindrical stamp radius R on the surface normal stress and surface in-plane stress are detailed. 相似文献
595.
596.
给出了Virasoro代数的一类一致有界不可分解权模的分类,即分类了这样的不可分解模,其合成因子或者都是中间模A_(0,0)的合成因子,或者都同构于中间模A_(a,b)(其中a(?)Z或b≠0,1). 相似文献
597.
求出了任意维经典非理想气体的硬心势、方阱势和Lennard-Jones势的第二位力系数,并给出了计算更高位力系数的方法与途径.结果表明:对于Lennard-Jones势,只有当维数n<6时,第二位力系数才收敛. 相似文献
598.
A Photoluminescent Metal Coordination Complex Constructed from Hydrothermal in situ Generated Quinoline‐monoacylhydrazidate Ligand 下载免费PDF全文
Qing‐Feng Yang Hong‐Cun Bai Bing Li Min Luo Juan Jin Jie‐Hui Yu Ji‐Qing Xu 《无机化学与普通化学杂志》2016,642(1):20-24
The quinoline‐monoacylhydrazidate‐coordinated transition‐metal compound Cd(QLH)2(H2O)2 ( 1 ) (QLH = 2,3‐quinoline dicarboxylhydrazidate) was obtained by the hydrothermal in situ acylation reaction between 2,3‐quinoline dicarboxylic acid and hydrazine hydrate. X‐ray single‐crystal diffraction analysis reveals that compound 1 features a mononuclear structure. Through the O–H ··· O and C–H ··· O hydrogen bonds between the neighboring molecules, the mononuclear units of 1 aggregate together into a 3D supramolecular network, which is stabilized by offset face‐to‐face π ··· π interactions. Compound 1 was characterized by IR spectroscopy, elemental analysis, TGA, and photoluminescence analysis, and it shows good photoluminescent property in the solid state at room temperature. In order to understand the emission mechanism, DFT calculations were carried out on the excited electronic states of compound 1 . 相似文献
599.
Copper sulfide nanoparticle-decorated graphene sheet (CuS/GR) was successfully synthesized and used as a signal amplification platform for electrochemical detection of alkaline phosphatase activity. First, CuS/GR was prepared through a microwave-assisted hydrothermal approach. The CuS/GR nanocomposites exhibited excellent electrocatalytic activity toward the oxidation of ALP hydrolyzed products such as 1-naphthol, which produced a current response. Thus, a catalytic amplification platform based on CuS/GR nanocomposite for electrochemical detection of ALP activity was designed using 1-naphthyl phosphate as a model substrate. The current response increased linearly with ALP concentration from 0.1 to 100 U L−1 with a detection limit of 0.02 U L−1. The assay was applied to estimate ALP activity in human serum samples with satisfactory results. This strategy may find widespread and promising applications in other sensing systems that involves ALP. 相似文献
600.
A New Energetic Complex [Co(2,4,3‐tpt)2(H2O)2]·2NO3: Synthesis,Structure, and Catalytic Thermal Decomposition for Ammonium Perchlorate 下载免费PDF全文
The energetic complex, [Co(2,4,3‐tpt)2(H2O)2] · 2NO3 ( 1 ) [2,4,3‐tpt = 3‐(2‐pyridyl)‐ 4‐(4'‐pyridyl)‐5‐(3′‐pyridyl)‐1H‐1,2,4‐triazole], was synthesized and characterized by single‐crystal X‐ray diffraction, thermogravimetric analyses, elemental analysis, X‐ray powder diffraction, and IR spectroscopy. The title complex is a 0D motif with a unit of [Co(2,4,3‐tpt)2(H2O)2]2+, whereas NO3– ions not only act as counter anions to balance the charge of the CoII cations, but also provide hydrogen bond interactions, which make the 0D motif into a 1D chain. Furthermore, the thermal decomposition of ammonium perchlorate (AP) with complex 1 was explored by differential scanning calorimetry (DSC) over the temperature range from 50–500 °C. AP is completely decomposed in a shorter time in the presence of complex 1 , and the decomposition heat of the mixture is 2.143 kJ g–1, significantly higher than pure AP. By Kissinger's method, the ratio of Ea/ln(A) is 11.87 for the mixture, which indicates that complex 1 shows good catalytic activity toward AP decomposition. 相似文献