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41.
Science China Chemistry - 相似文献
42.
A time-stepping finite-element (FE) and boundary-element (BE) coupling method was implemented to include 3D transient eddy
current under electromagnetic heating effects in electromagnetic launchers. Lagrangian formulations were used to model electromagnetic
and thermal diffusive processes with moving conductors. The finite-element formulation was employed for the general diffusion
equation in a bounded conductor region including rail and armature; while, in the exterior region, the boundary element method
was developed for Laplace's equation. The coupled boundary was employed directly on the surface of conductors and no special
treatment on boundary was required. The electromagnetic and temperature fields were coupled through iterative calculations.
This method results in considerable time saving in modeling as it eliminates the surrounding air region. 相似文献
43.
44.
A highly enantioselective catalyst generated by a combination of BINOL and another ligand with Ti(OiPr)4 was found to be highly effective for the alkynylzinc addition to aromatic aldehydes with enantioselectivities as high as >99%. 相似文献
45.
Other Index
Key Word Index for Volume 11 相似文献46.
Kwok W. Chiu David Lyons Geoffrey Wilkinson Mark Thornton-Pett Michael B. Hursthouse 《Polyhedron》1983,2(8):803-810
The reduction of WCl4(PMe3)3 by sodium amalgam in presence of phenylacetylene gives W(PMe3)(PhCCH)3 (A). Reduction in presence of methylisocyanide gives W(PMe3)2(MeNC)4 (B), while in presence of excess PMe3 in tetrahydrofuran under hydrogen, WH2Cl2(PMe3)4 (C) is formed. The reaction of WCl2(PMe3)4 with methanol in tetrahydrofuran gives mixtures of WH2Cl2(PMe3)4 and WOC12(PMe3)3 (D).The structures of A, B, and D have been determined by X-ray diffraction. 相似文献
47.
K.W. Kwok C.K. Wong R. Zeng F.G. Shin 《Applied Physics A: Materials Science & Processing》2005,81(1):217-222
It is experimentally known that a polymer matrix phase in a composite of ferroelectric particles dispersed in a ferroelectric polymer can be polarized by using a few cycles of an ac field, without causing much disturbance to the state of polarization of the inclusion particles. This paper attempts to investigate this special poling process for a typical ferroelectric composite system of lead zirconate titanate (PZT) ceramic particles in a vinylidene fluoride-trifluoroethylene (P(VDF-TrFE)) copolymer matrix, upon the application of 10 Hz ac fields of various amplitudes. Compared to a copolymer sample, the composite samples can be polarized at a lower field, and hence show a larger remanent polarization at the same poling field. Among the composites, the observed remanent polarization increases with increasing ceramic volume fraction. These experimental observations can be understood by a simple model, in which space charges are allowed to accumulate at the particle-matrix interfaces because of the electrical conductivity of the constituents. At a fast switching poling field of 10 Hz, the calculation shows that conductivity and charge accumulation effects in the composite are only minimal. Accordingly, although the PZT phase as well as the copolymer phase are both polarized under the ac field, the ceramic phase is only polarized to about 10% when the copolymer phase is almost fully polarized. Thus, one can still use an ac field to polarize only the copolymer phase of the composite without altering the polarization state of the ceramic phase significantly. PACS 77.22.Ej; 77.84.Lf 相似文献
48.
We carried out experimental studies of the self-assembly of metallic micron-size particles in poorly conducting liquid subject to a constant electric field. Depending on the experimental conditions, the particles self-assemble into long chains directed along the electric field lines and form vortices and other structures. The vortices perform Brownian-type random motion due to self-induced chaotic hydrodynamic flows. We measured the diffusivity constant of the vortices and the conductivity and mechanical stiffness of the chains. 相似文献
49.
The moving contact line problem of liquid-vapor interfaces was studied using a mean-field free-energy lattice Boltzmann method recently proposed [Phys. Rev. E 2004, 69, 032602]. We have examined the static and dynamic interfacial behaviors by means of the bubble and capillary wave tests and found that both the Laplace equation of capillarity and the dispersion relation were satisfied. Dynamic contact angles followed the general trend of contact line velocity observed experimentally and can be described by Blake's theory. The velocity fields near the interface were also obtained and are in good agreement with fluid mechanics and molecular dynamics studies. Our simulations demonstrated that incorporating interfacial effects into the lattice Boltzmann model can be a valuable and powerful alternative in interfacial studies. 相似文献
50.