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91.
Slaheddine Chaabouni Jean Michel Savariault Abdelhamid Ben Salah 《Journal of chemical crystallography》2004,34(10):661-664
The tris (phenylammonium) chloride pentachloroantimonate (III) monohydrate salt is triclinic
with the following cell parameters: a = 9.4283(3), b = 11.4482(3), c = 13.1748(3)Å, = 113.493(2), = 90.381(2), = 97.331(1)°, V = 1290.86(6)Å3, with Z = 2 formula units. The structure consists of [C6H5NH3]+ cations, water molecules, Cl– anions, and SbCl5 square pyramids. Hydrogen bonds, established through water molecule, link the anions [SbCl5]2– and Cl– and make an infinite chain in the [011] direction. Chains are linked together via another hydrogen bond network originating from the ammonium groups. A distortion of the SbCl5 square pyramid can be attributed to the stereo activity of the Sb(III) lone electron pair. 相似文献
92.
Slaheddine Chaabouni Jean Michel Savariault Abdelhamid Ben Salah 《Journal of chemical crystallography》2004,34(3):223-227
The salt di(N-benzyl piperidinium) pentachloroantimonate(III) dihydrate crystallizes in the orthorhombic system with space group Cmc21, the unit cell dimensions are: a = 29.383(1), b = 10.509(2), c = 9.941(1) Å, with Z = 8. The structure shows a layer arrangement perpendicular to the a axis: planes of SbCl6 octahedra alternate with planes of [C12H17N]+ cations. The SbCl6 octahedra are connected through a O(W)–HCl hydrogen bonds and a chlorine bridge, so that infinite unidimensional chains of composition [SbCl5(H2O)2]2n–
n are formed in the structure along the c direction. These chains are connected to [C12H17N]+ entities by N–HCl and N–HO(W) hydrogen bonds, forming a three-dimensional network. It was found that lengths of Sb–Cl bonds may differ from each other. The differences shown as a distortion of the SbCl6 octahedra were attributed to the Sb(III) lone electron pair stereoactivity. 相似文献
93.
David Duracher Abdelhamid Elaïssari Christian Pichot 《Journal of polymer science. Part A, Polymer chemistry》1999,37(12):1823-1837
Thermosensitive crosslinked polymer latexes have been synthesized by precipitation polymerization of N-isopropylmethacrylamide (NIPMAM) as a main monomer, methylene bis-acrylamide (MBA) as a crosslinker, and potassium persulfate (KPS) as the initiator. Polymerizations kinetics were first investigated by studying both the influence of crosslinker (MBA) and initiator (KPS) concentrations and temperature effects on the polymerization conversion, the particle size, and water-soluble polymer (WSP) as a function of time. Particle size analysis by Scanning Electron Microscopy (SEM) showed that a short nucleation step afforded the synthesis of highly monodispersed latexes. In addition, a strong dependence of WSP formation on MBA and KPS concentration and polymerization temperature was found, as well. Comparison of particle size by SEM and quasielastic light scattering clearly evidenced the dramatic effect of temperature on particle size. Lower critical solubility temperatures (LCST) of latexes were determined and compared. Finally, based on these results, the mechanism of particle formation in this polymerization process is discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1823–1837, 1999 相似文献
94.
Thiazolylcyanothioacetanilides react with α‐haloketones and haloesters to give the corresponding thiophene or thiazole derivatives according to the reaction conditions. Pyrazolo[1,5‐a]pyrimidines and pyrazolo[5,1‐c]triazines were synthesized by reaction of 3‐amino‐4‐(4′‐arylthiazol‐2′‐yl)‐5‐phenylaminopyrazole with different reagents. Structures of the new compounds were confirmed by elemental analyses, spectral data, and alternative methods of synthesis whenever possible. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 508–516, 1999 相似文献
95.
Sihem Khaddar-Zine Abdelhamid Ghorbel Claude Naccache 《Journal of molecular catalysis. A, Chemical》1999,150(1-2):223-231
The oxidation state, the mobility and the molecular structure of chromium species present on CrOx–Al2O3 catalysts have been studied by combined diffuse reflectance spectroscopy, EPR and reduction–extraction by ethane 1,2 diol. CrO42− species exist on the alumina surface in the form of loosely-interacting species on hydrated surface (species A) and in the form of strongly bonded species on dehydrated Al2O3 surface (species B). The CrO42− species show high mobility and are probably responsible for the formation of CrOx clusters. 相似文献
96.
97.
反相微乳液合成30~100nm磁性聚合物纳米微球 总被引:12,自引:0,他引:12
利用反相微乳液一步法成功地制备了磁性聚合物纳米微球,微球粒径在30~100nm左右,均一性较好,研究表明,Fe(Ⅱ)浓度对微乳液和微胶乳的稳定性有很大影响,碱的种类、AOT和单体的含量能控制微球粒径,用振动探针式磁强仪(VSM)测定了不同比例的[Fe(Ⅱ)]/[Fe(Ⅲ)]所合成的聚合物微球的磁性,发现温度对合成高磁饱和强度和超顺磁性起关键作用,合成的磁性聚合物微胶乳透明且稳定性较好. 相似文献
98.
Abdelhamid Meziani 《Journal of Differential Equations》2007,239(1):16-37
For any given n∈Z+ and k∈Z+, infinitesimal bendings of order n and of class Ck are constructed for a class of surfaces in R3. These surfaces are given as graphs of homogeneous polynomials P(x,y) and they have positive curvature except at the origin. 相似文献
99.
Abdelhamid Bourass Bouchaib Ferrahi Bertram M. Schreiber Maria Victoria Velasco 《Set-Valued Analysis》2005,13(2):105-124
We present a generalization of the Uniform Boundedness Principle valid for random multivalued linear operators, i.e., multivalued linear operators taking values in the space L0(,Y) of random variables defined on a probability space
with values in the Banach space Y. Namely, for a family of such operators that are continuous with positive probability, if the family is pointwise bounded with probability at least >0, then the operators are uniformly bounded with a probability that in each case can be estimated in terms of and the index of continuity of the operator. To achieve this result, we develop the fundamental theory of multivalued linear operators on general topological vector spaces. In particular, we exhibit versions of the Closed Graph Theorem, the Open Mapping Theorem, and the Uniform Boundedness Principle for multivalued operators between F-spaces.Mathematics Subject Classifications (2000) 46A16, 46A30, 47A06, 47B80, 60H25. 相似文献
100.
A modified integral Werner method is used to calculate pressure scattered by an axisymmetric body immersed in a perfect and compressible fluid subject to a harmonic acoustic field. This integral representation is built as the sum of a potential of a simple layer and a potential of volume. It is equivalent to the exterior Helmholtz problem with Neumann boundary condition for all real wave numbers of the incident acoustic field. For elastic structure scattering problems, the modified Werner method is coupled with an elastodynamic integral formulation in order to account for the elastic contribution of the displacement field at the fluid/structure interface. The resulting system of integral equations is solved by the collocation method with a quadratic interpolation. The introduction of a weighting factor in the modified Werner method decreases the number of volume elements necessary for a good convergence of results. This approach becomes very competitive when it is compared with other integral methods that are valid for all wave numbers. A numerical comparison with an experiment on a tungsten carbide end-capped cylinder allows a glimpse of the interesting possibilities for using the coupling of the modified Werner method and the integral elastodynamic equation used in this research. 相似文献