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91.
Summary Direct reaction of K2MCl4 (M=Pt or Pd) with acetamide leads reproducibly to complexes which can be formulated as [Pt(C2H4ON)2Cl]n and Pd4(C2H4ON)7(OH)2. Analytical and spectroscopic (i.r., n.m.r. and e.p.r.) data support the existence of polynuclear structures involving bridging ligands and partially oxidized metal centres. 相似文献
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94.
Physical properties-structure relationships have been investigated for polyurethane networks. Sol fraction, swelling and elastic modulus have been measured. Structural parameters derived from these measurements have been compared with those from theoretical models. As a result, the behaviour of these these networks appears to lie between those of phantom and affine network models. 相似文献
95.
63-Cu and 75-As quadrupole resonance results have been obtained for the tetrameric triethylarsine copper(I) halides (Cl, Br and I). Unusual behaviours of the temperature dependence of the 63-Cu and 75-As quadrupole resonance lines have been observed simultaneously. Between 77 and 300 K, the chlorine derivative undergoes two structural phase changes at 93 and 173 K, while phase transformations occur at 152 and 86 K respectively for the bromine and iodine derivatives. 相似文献
96.
Cremer Sauer Strubecker Walther Durand Kuntzmann Stiefel 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1957,8(5):425-427
Ohne Zusammenfassung 相似文献
97.
Ardès-Guisot N Durand JO Granier M Perzyna A Coffinier Y Grandidier B Wallart X Stievenard D 《Langmuir : the ACS journal of surfaces and colloids》2005,21(21):9406-9408
Despite the importance of the isocyanate group in chemistry, very few examples of isocyanate-modified silicas have been reported, and all of the strategies described so far led to partial or total hydrolysis or condensation of the isocyanate group. By synthesizing trichlorosilane isocyanate as the coupling reagent, we show that oxidized silicon wafers are successfully modified with the isocyanate group. Our method is achieved in mild conditions, at low temperature, without side-reactions and allows the formation of a self-assembled monolayer (SAM) of isocyanates. The isocyanate group then offers a flexible way to further functionalize silica substrates with different nucleophiles, due to its high and specific reactivity. 相似文献
98.
Syntheses of the enantiomerically pure phytoprostanes B(1) type I and II are described starting from furfural and n-propylfuran. Key steps include the preparation of the Freimanis (+/-)-hydroxycyclopentenone and Wittig coupling using chiral phosphonium salts. 相似文献
99.
Necessary and Sufficient Conditions to be an Eigenvalue for Linearly Recurrent Dynamical Cantor Systems 总被引:2,自引:0,他引:2
Bressaud Xavier; Durand Fabien; Maass Alejandro 《Journal London Mathematical Society》2005,72(3):799-816
Necessary and sufficient conditions are given for linearly recurrentCantor dynamical systems to have measurable and continuous eigenfunctions.Also an example of a linearly recurrent system with a nontrivialKronecker factor and a trivial maximal equicontinuous factoris constructed explicitly. 相似文献
100.
We shall show that a complete Riemannian manifold of dimension n with Ric?n−1 and its n-st eigenvalue close to n is both Gromov-Hausdorff close and diffeomorphic to the standard sphere. This extends, in an optimal way, a result of P. Petersen [Invent. Math. 138 (1999) 1] (as a by-product, we fill a gap stated in the erratum [Invent. Math. 155 (2004) 223]). We shall also show that a manifold with Ric?n−1 and volume close to is both Gromov-Hausdorff close and diffeomorphic to a space form Sn/π1(M). This extends results of T. Colding [Invent. Math. 124 (1996) 175] and T. Yamaguchi [Math. Ann. 284 (1989) 423]. 相似文献