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排序方式: 共有322条查询结果,搜索用时 328 毫秒
91.
92.
The thermal decompositions of anhydrous fluorosilicates M2SiF6 (M=Li, Na, K, Rb, Cs) and MSiF6 (M=Ca, Sr, Ba) were investigated. The decompositions proceeded according to a simple acid-base mechanism with evolution of SiF4. The influence of the cationic counter-ion acidity (expressed by means of the electronegativity force) on the course of thermal decomposition was estimated quantitatively. 相似文献
93.
94.
95.
The results of experiments on application of NaH2PO4 as a binding agent for ceramic kaolin samples were presented. The experiments were carried out at temperatures of 973, 1073
and 1173 K and NiO and CoO additives were used as tempering agents. The parameters of the obtained samples with NaH2PO4 were compared with the samples compressed with water only. The materials of 3-4 times higher bending strength, lower water
absorption as well decreased open porosity were prepared during these experiments. The binding function of the NaH2PO4 additive relies on creation of some compounds in reaction between the products of its condensation and products of kaolin
decomposition. Finally a ceramic material of prospective properties was created.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
96.
Andrzej Więkowski Jerzy Sobkowski Piotr Zelenay 《Journal of Electroanalytical Chemistry》1977,84(1):109-116
The formic acid adsorption on an electrochemically prepared rhodium electrode has been studied by the radiochemical method. Electrochemical properties of the rhodium electrode surface in 0.5 M H2SO4 have been investigated by cyclic voltammetry. It has been shown that starting from E=0.20 V the rate of HCOOH adsorption is markedly potential dependent being practically independent of the electrode potential up to E=0.20 V. It seems that the HCOOH adsorption process may be explained on the basis of the two-sites kinetics model. The data obtained for HCOOH adsorption on a rhodium electrode have been compared with those for a platinum electrode reported previously. 相似文献
97.
Kaizaki Sumio Kita Przemysław Wiśniewska Joanna Sakagami Narumi 《Transition Metal Chemistry》2000,25(4):363-368
The [Cr(NCS)(edtrp)]−, [Cr(NCS)(R-pdtrp)]− and [Cr(NCS)(S-pdtra)]− complexes, that are derivatives of the trans-equatorial isomers of [Cr(edtrp)(H2O)]° and [Cr(R-pdtrp)(H2O)]° and the cis-equatorial isomer of [Cr(S-pdtra)-(H2O)]° (edtrp = ethylenediamine-N,N,N′-tripropionate, R-pdtrp = R-propane-1,2-diamine-N,N,N′-tripropionate, S-pdtra = S-propane-1,2-diamine-N,N,N′-triacetate) undergo aquation in alkaline media with a strong dependence of the rate on [OH−] for the trans-equatorial isomers and a very weak dependence for the cis-equatorial isomer. The thiocyanate ligand release follows a stereoretentive course for all reactants. Based on kinetic data
the reaction mechanism has been discussed. Rate differences between the isomers are interpreted in terms of an interchange
via a conjugate base (I c.b.) mechanism, assuming an equilibrium between the cis-equatorial-CrIII-S-pdtra complexes with penta- and tetradentate coordination of the edta-like ligand.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
98.
Excellent regio- and stereoselectivity during nitrile addition to dienylium-Fe(CO)(3) can be achieved with perchlorate salts, allowing the preparation of the 1-oxo- and 3-oxo-2-azaspiro[5.5]undecane ring systems. The phthalimide complex 2 was prepared in high yield by Mitsunobo reaction. 相似文献
99.
E. Kowalska J. Radomska P. Konarski R. Diduszko J. Oszczudłowski T. Opalińska M. Więch Z. Duszyc 《Journal of Thermal Analysis and Calorimetry》2006,86(1):137-140
Two components
of electronic wastes (sample A – a mixture of three types of printed
circuit boards, sample B – a mixture of electronic junctions with metal
wires) were investigated using thermogravimetric analysis (TG). Thermogravimetric
and derivative thermogravimetric data (TG and DTG) give information on the
thermal stability of A and B samples and allows finding the correct conditions
for their degradation using pyrolysis in an experimental system, built on
the laboratory scale for utilization of hazardous wastes. X-ray fluorescence
measurements prove that brominated flame retardant is present in sample A,
whilst chlorinated flame retardant is a probable component of sample B. Preliminary
liquid chromatography of oil products obtained as a result of thermal waste
degradation shows that the hydrocarbons released during pyrolysis could be
used as a fuel. 相似文献
100.
Evolution of hydrogen during thermal decomposition of some MIIHPO3 (M= Mg, Ca, Zn, Sr, Cd, Ba) phosphities under nitrogen atmosphere was investigated. Step mechanism of thermal decomposition has been proposed.
Zusammenfassung Es wurde die Wasserstoffentwicklung während der thermischen Zersetzung einiger Phosphite MII)HPO3 (mitM=Mg, Ca, Zn, Sr, Cd, Ba) in einer Stickstoffatmosphäre untersucht. Es wurde ein schematischer Mechanismus für die thermische Zersetzungsreaktion gegeben.相似文献