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101.
102.
103.
104.
Solvolysis of asymmetric homoallylic triflates bearing a terminal stannyl substituent gives disubstituted cyclopropanes and bicyclopropanes bearing differentiated termini in high enantiopurity. 相似文献
105.
Solid solutions of GeO2 in Fe2O3 were prepared by mechanically mixing the solids and firing at 1000°C in air, and from a gel obtained by the addition of an alcohol solution of germanium ethoxide to iron dissolved in HNO3. The dried gel was then heated at 1000°C. The solubility limit is 5 mole% GeO2, Fe1.95Ge0.05O3. Similar procedures were used to prepare solid solutions with Si and the solubility limit is greater than 4 mole% SiO2. Firing of mixtures or gels of Fe2O3 containing Mg produces a spinel phase even at the lowest detectable concentrations. The resistivity of pressed pellets of Fe2?xGexO3 varies from about 106 ohm-cm for x = 0 to about 10?1 ohm-cm for x = 0.05. The photoassisted electrolysis of water at Ge-doped Fe2O3 electrodes is demonstrated. The photoelectrochemical cell showed a 0.29-V open-circuit voltage, 1.2-mA/cm2 short-circuit current, 0.31 fill factor, and 0.06% power efficiency. 相似文献
106.
Glass capillaries coated with Chirasil-Val, a chirally functionalised polysiloxane, are capable in principle of resolving all protein amino-acid enantiomers in a single run and within a short analysis time, thus allowing for example the quantitative amino acid determination by enantiomer labelling. The elution characteristics of the individual amino acids however are also dependent upon the chemical nature of the capillary wall surface, and a surface pretreatment is found to be necessary if all protein amino acids are to be analysed. Of the various methods of pretreatment tested, etching of borosilicate glass with gaseous HCl followed by deposition of colloidal silicic acid is considered to be the most suitable. 相似文献
107.
A family of homochiral metal carboxylate coordination polymers have been synthesized by treating 2,2'-dihydroxy-1,1'-binaphthalene-6,6'-dicarboxylic acid (H(2)BDA) with metal salts at elevated temperatures. BDA ligands link adjacent metal centers to form 1D coordination polymeric chains using the carboxylate functionality, while the hydroxyl groups of BDA ligands form H-bonds with carboxylate oxygen atoms to link 1D coordination polymeric chains into open frameworks of higher dimensionality. We also present evidence for the important role played by H-bonds in the stabilization of open framework structures which allows for the hierarchical assembly of chiral porous solids. 相似文献
108.
The regioselectivity of the intramolecular [2+2] photocycloaddition of certain 6-allylcyclohexenones appears to be largely independent of the substituent (H,OR) on the dital terminus of the isolated double bond. 相似文献
109.
Michael I. Bruce Jennifer K. Walton Michael L. Williams Brian W. Skelton Allan H. White 《Journal of organometallic chemistry》1981,212(3):C35-C38
Contrary to some previously depicted structures, the proton in HC5(CO2Me)5 is bonded to two oxygens rather than to carbon; the lithium ion in Li[C5(CO2Me)5] (H2O) is tetrahedrally coordinated by two carbonyl oxygens from one C5 anion, one from a second anion, and a water molecule. 相似文献
110.
D. White 《International Journal of Theoretical Physics》1985,24(2):201-216
Based upon a recently published work in which a model for hadron pair production via virtual synchrotron radiation in uniform magnetic fields was introduced, an ansatz for calculating
s
is presented. The resulting function is unique within the above-mentioned context. Along with a scheme introduced in which vector mesons arise by virtue of quark spin-flip with accompanying gluon emission, the
s
function is used to successfully explain the observed hadronic widths of the ,, andJ mesons. In addition the hadronic and leptonic widths of the upsilon meson are calculated. Based upon gathered upsilon data, a charge on theb quark of (2e/3) is found to be consistent with the above model. Finally, the derived
s
function is compared with results of gauge-theoretical calculations. 相似文献