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51.
From oxygen and nitrous oxide indices of polypropylene-chlorinated paraffin mixtures it can be deduced that, in addition to the flame poisoning effect of HCl eliminated by the chloroparaffin, the lower flammability of the volatile products formed by thermal degradation of polypropylene heated in the presence of this additive seems to contribute to its fire retardance activity. 相似文献
52.
A method based on the analytical evaluation of residual unsaturations and on the knowledge of the cyclization ratios is presented for the determination of the cyclopolymer composition in terms of structural units. The application of this method to the products of the free radical polymerization of vinyl-transcrotonate and of divinyl ether is described. 相似文献
53.
Sophie Chausson Richard Retoux Jean-Michel Rueff Loïc Le Pluart Pierre-Jean Madec Paul-Alain Jaffres Giovanni Camino 《Macromolecular Symposia》2011,301(1):40-45
Summary: We report herein a study performed on a layered titanoniobate KTiNbO5 modified by octadecylamine to evaluate the fire retardancy properties of this novel hybrid nanofiller dispersed in PA12 and LLDPE, by polymer melt intercalation. The nanocomposites have been characterized using Electron Microscopy techniques to evaluate the degree of exfoliation and the morphologies. Thermogravimetric analyses and cone calorimeter tests have been carried out to assess the fire retardant performances. 相似文献
54.
Summary: In this paper we investigate the influence of various nanofilllers' aspect ratio, chemical nature and organic modification on some selected polypropylene properties, such as crystallinity, thermal and mechanical resistance and fire behaviour. Materials were prepared by twin-screw extrusion and characterized by means of scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, tensile and cone calorimeter tests. Fillers characteristics were found to influence at different extents, and for different reasons, the material final properties. 相似文献
55.
The Job Shop Scheduling Problem (JSP) is an example of a combinatorial optimization problem that has interested researchers
for several decades. In this paper we confront an extension of this problem called JSP with Sequence Dependent Setup Times
(SDST-JSP). The approach extends a genetic algorithm and a local search method that demonstrated to be efficient in solving
the JSP. For local search, we have formalized neighborhood structures that generalize three well-know structures defined for
the JSP. We have conducted an experimental study across conventional benchmark instances showing that the genetic algorithm
exploited in combination with the local search, considering all three neighborhoods at the same time, provides the best results.
Moreover, this approach outperforms the current state-of-the-art methods. 相似文献
56.
Strongly absolute bases are, roughly speaking, purely nonlocally convex bases in quasi-Banach spaces. When, in addition, they
are unconditional then the discrete lattice structure they induce in the space is lattice anti-Euclidean. In this brief note
we characterize the complemented unconditional basic sequences in those quasi-Banach spaces with strongly absolute unconditional
basis, and use this result to derive the uniqueness of unconditional basis in many classical quasi-Banach spaces. 相似文献
57.
For a strongly connected digraph D the minimum ,cardinality of an arc-cut over all arc-cuts restricted arc-connectivity λ′(D) is defined as the S satisfying that D - S has a non-trivial strong component D1 such that D - V(D1) contains an arc. Let S be a subset of vertices of D. We denote by w+(S) the set of arcs uv with u ∈ S and v S, and by w-(S) the set of arcs uv with u S and v ∈ S. A digraph D = (V, A) is said to be λ′-optimal if λ′(D) =ξ′(D), where ξ′(D) is the minimum arc-degree of D defined as ξ(D) = min {ξ′(xy) : xy ∈ A}, and ξ′(xy) = min(|ω+({x,y})|, |w-({x,y})|, |w+(x) ∪ w- (y) |, |w- (x) ∪ω+ (y)|}. In this paper a sufficient condition for a s-geodetic strongly connected digraph D to be λ′-optimal is given in terms of its diameter. Furthermore we see that the h-iterated line digraph Lh(D) of a s-geodetic digraph is λ′-optimal for certain iteration h. 相似文献
58.
ER Badman GE Patterson JM Wells RE Santini RG Cooks 《Journal of mass spectrometry : JMS》1999,34(8):889-894
Dual-detector differential non-destructive Fourier transform detection in a quadrupole ion trap is shown to improve signal intensity and reduce noise compared with spectra recorded using a single detector. A larger area detector in each end-cap electrode is machined to fit its hyperbolic shape and so minimize field imperfections on the z-axis. Argon, acetophenone and bromobenzene spectra were recorded to allow a comparison between single- and dual-detector (differential) modes of detection and to demonstrate the improvement achieved with differential detection. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
59.
Polubarinova-Kochina's analytical differential equation methodis used to determine the pseudo-steady-state solution to problemsinvolving the freezing (solidification) of wedges of liquidwhich are initially at their fusion temperature. In particular,we consider four distinct problems for wedges which are: freezingwith the same constant boundary temperature, freezing with thesame constant boundary heat fluxes, freezing with distinct constantboundary temperatures and freezing with distinct constant fluxesat the boundaries. For the last two problems, a Heun's differentialequation with an unknown singularity is derived, which in bothcases admits a particularly elegant simple solution for thespecial case when the wedge angle is . The moving boundariesobtained are shown pictorially. 相似文献
60.
Alves GA Amato S Anjos JC Appel JA Astorga J Bernard T Bracker SB Cremaldi LM Darling CL Dixon RL Errede D Gay C Green DR Jedicke R Karchin PE Kwan S Lueking LJ de Mello Neto JR Metheny J Milburn RH de Miranda JM da Motta Filho H Napier A Passmore D Rafatian A dos Reis AC Ross WR Santoro AF Sheaff M Souza MH Spalding WJ Stoughton C Streetman ME Summers DJ Takach SF Wallace A Wu Z 《Physical review letters》1994,72(6):812-815