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921.
Acta Mathematicae Applicatae Sinica, English Series - In this work, it is aimed to find one- and two-soliton solutions to nonlinear Tzitzeica-Dodd-Bullough (TDB) equation. Since the double... 相似文献
922.
923.
In this study, the normal (σx, σy, σz) and shear stress (τxy, τyz, τzx) distributions occurring in a bi-adhesively bonded T-joint with was investigated via a non-linear three dimensional finite element analysis. For this purpose, first of all, using 2024-T3 aluminum alloy as the adherend and the support, a two-part paste (DP 460) and a film type (SBT 9244) as adhesive, two different types of T-joint samples (single-adhesively bonded T-joint and bi-adhesively bonded T-joint) were produced for experimental studies. After experimental studies on the three different T-joint types were conducted, stress analyses in the T-joints were performed with a three-dimensional finite element analysis by considering the geometrical non-linearity and the material non-linearities of the adhesive (DP460 and SBT9244) and adherend (AA2024-T3). Finally, for a given adherend, the lower the stiffness of the adhesive used in the overlap, the lower the stress concentration, leading to potentially higher joint strength. The use of relatively low stiffness adhesives at the ends of the overlap in a bi-adhesive can decrease the stress concentration and, therefore, potentially lead to higher joint strength. 相似文献
924.
925.
The advances in the technological infrastructure and in the Internet led electronic auctions to become popular. With online sites, people buy/sell inexpensive products/services through auctions. In this paper, we develop an interactive approach that provides aid to both the buyer and the bidders in a bi-attribute, multi-item auction environment. Our approach is applicable for both reverse and forward auctions. We test our approach for underlying linear preference functions of the buyer. We also adapt it as a heuristic for the case the buyer has a nonlinear preference function. The test results show that our approach works well. 相似文献
926.
Sir James Lighthill proposed in 1992 that acoustic streaming (AS) within the mammalian cochlea could play a role in the transmission of acoustic signals to the auditory sensory cells. Microelectromechanical devices for mixing and pumping, based on the acoustic streaming effect were introduced in the mid 1990s. Nature may have preceded this invention by 2.7 Gyr. We believe that acoustic streaming produced by nanometer scale membrane vibrations is widespread in cell biology. Flows generated by acoustic streaming could be produced along the “raphes” (central channels) of silica coated diatoms. Other possible instances are yeast cells and erythrocytes whose membranes generate nanoscale vibrations. We hypothesize that some of the most ancient organisms use acoustic streaming not only for self-propulsion but also to enhance their nutrient uptake. In this paper we focus on a motile strain of Synechococcus, a cyanobacterium whose mechanism for self-propulsion is not known. The calculations presented here show that a traveling surface acoustic wave (SAW) could account for the observed velocities. These SAWs would also produce a non-negligible Stokes layer surrounding the cell, motion within this region being essentially chaotic. Therefore, an AS mechanism would be biologically advantageous, enhancing localized diffusion processes and consequently, chemical reactions. Finally, we discuss possible experiments to support (or rule out) the AS model vs. other contending explanations for Synechococcus locomotion. 相似文献
927.
Azido Beryllates with Adamantan‐like Structures: Synthesis, IR Spectra, and Crystal Structures of (Ph4P)2[Be4X4(μ‐N3)6] (X = Cl, Br) The azido beryllates (Ph4P)2[Be4X4(μ‐N3)6] (X = Cl 1a , X = Br 1b ) have been prepared by the reaction of Me3SiN3 with the halogeno beryllates (Ph4P)2[Be2Cl6] and (Ph4P)2[Be2Br6], respectively, in CH2Cl2 and CH2Br2 solution, respectively. Both complexes form moisture sensitive, colourless crystals, which are nonexplosive with respect to mechanical or thermal stress. They are characterized by IR spectroscopy and by crystal structure determinations. 1a and 1b crystallize isotypically in the space group C2/c with 12 formula units per unit cell. Whereas 1a was only refined to R1 = 0.13, which is caused by disordering, 1b could be refined to R1 = 0.066. The structures contain adamantanlike dianions [Be4X4(μ‐N3)6]2— with two symmetry nonequivalent individuals which differ only slightly from one another. The Be4N6 core is formed by bridging function of the α‐nitrogen atoms of the azide groups with BeN bond lengths of 172.5 and bond lengths Nα—Nβ = 123.2 pm and Nβ—Nγ = 113.1 pm on average in the structure of 1b . 相似文献
928.
John W. Fowler Esma S. Gel Murat M. Köksalan Pekka Korhonen Jon L. Marquis Jyrki Wallenius 《European Journal of Operational Research》2010
We present a new hybrid approach to interactive evolutionary multi-objective optimization that uses a partial preference order to act as the fitness function in a customized genetic algorithm. We periodically send solutions to the decision maker (DM) for her evaluation and use the resulting preference information to form preference cones consisting of inferior solutions. The cones allow us to implicitly rank solutions that the DM has not considered. This technique avoids assuming an exact form for the preference function, but does assume that the preference function is quasi-concave. This paper describes the genetic algorithm and demonstrates its performance on the multi-objective knapsack problem. 相似文献
929.
Diacetone Alcohol as Complex Ligand. Crystal Structures of [MnBr2{O=C(Me)CH2–C(Me)2OH}2] and [M{O=C(Me)CH2–C(Me)2OH}2][MCl4] with M = Fe, Co, and Zn The metal halides MnBr2 and MCl2 (M = Fe, Co, Zn) react with diacetone alcohol (4-hydroxy-4-methyl-2-pentanon) forming the title compounds, which are characterized by IR spectroscopy and crystal structure analyses. [MnBr2{O=C(Me)CH2–C(Me2)OH}2] ( 1 ): Space group C2/c, Z = 4, lattice dimensions at 293 K: a = 1189.2(4), b = 1317.2(3), c = 1200.0(3) pm, β = 102.25(3)°, R1 = 0.0256. In 1 the manganese atom is coordinated in a distorted octahedral fashion by the two cis bromine atoms and by the four oxygen atoms of the two diacetone alcohol chelating molecules. The distances Mn–[OH] (223.8 pm) and Mn–[O=C] (222.1 pm) are only slightly different. [M{O=C(Me)CH2–C(Me)2OH}2][MCl4] [M = Fe ( 2 ), Co ( 3 ), Zn ( 4 )]: 2 and 3 crystallize isotypically with each other in the space group Pc, Z = 4. Lattice dimensions for 2 at 293 K: a = 865.8(3), b = 926.3(2), c = 1401.5(1) pm, β = 104.19(2)°, R1 = 0.0421. Lattice dimensions for 3 at 293 K: a = 872.3(1), b = 925.7(1), c = 1394.2(3) pm, β = 104.79(2)°, R1 = 0.0481. As in 1 , the metal atoms of the [M{O=C(Me)CH2–C(Me)2OH}2]2+ ions in 2 and 3 are chelated in a distorted octahedral fashion by two diacetone alcohol molecules and associated cis via two μ-Cl atoms of the [MCl4]2– anions to form strands. [Zn{O=C(Me)CH2–C(Me)2OH}2][ZnCl4] ( 4 ): Space group C2/c, Z = 4. Lattice dimensions at 213 K: a = 1582.27(13), b = 1356.15(13), c = 941.93(7) pm, β = 107.283(10)°, R1 = 0.0328. The zinc atom of the dication in 4 is associated in a distorted octahedral fashion by the two diacetone alcohol chelating molecules in the equatorial positions and trans by two μ-Cl atoms of the [ZnCl4]2– ions to form strands. 相似文献
930.
Edward F. Cassidy Han X. Xiao Kurt C. Frisch Harry L. Frisch 《Journal of polymer science. Part A, Polymer chemistry》1984,22(10):2667-2683
Three-component IPN systems made from polyurethanes, epoxies, and poly(methacrylates) containing charge groups in the backbones of the constituent networks have been prepared. Specific attractive forces that occurred among the various networks helped to compatibilize them and aided in the formation of true homogeneous topologically interpenetrating polymer networks. These three-component polymer alloys, including full-IPN's, pseudo-IPN's, and graft-IPN's, were characterized by means of mechanical spectroscopy, electron microscopy, and stress–strain properties. In addition, some adhesion studies were carried out (lap shear strength and peel strength). A comparison of the different types of three-component polymer alloys showed that better properties were generally exhibited by the graft-IPN's and full-IPN's containing opposite charge groups. 相似文献