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21.
Using infrared reflection absorption spectroscopy (IRRAS), quartz crystal microbalance (QMB) measurements, and X-ray photoelectron spectroscopy (XPS) in combination with chemical derivatization techniques the VUV photolysis of polyethylene (PE), polypropylene (PP), and polystyrene (PS) was investigated. A mass balance obtained from the quantification of the data was used to suggest reaction path ways. Although PE and PP behave similar, the mass loss is about 8 times higher in the case of PP. These differences originate from the higher disproportionation to recombination ratio for the branched polymer. Both polymers form double bonds and at extended treatment times they tend to crosslink. PS is rather stable due to the possibility of the energy dissipation by fluorescence. 相似文献
22.
Preparation, 11B NMR, Vibrational Spectra, and Crystal Structure of [(C5H5N)2CH2][1-(O2N)B10H9] By reaction of [B10H10]2? in aqueous acetonitrile with a saturated solution of NO2 in dichloromethane [1-(O2N) · B10H9]2? and [B10H9(NO)B10H9]3? are formed which can be separated by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose from the starting compound. The X-ray structure determination of [(C5H5N)2CH2][1-(O2N)B10H9] (triclinic, space group P1 , a = 7.1530(9), b = 8.3753(8), c = 15.198(2) Å, α = 96.00(1), β = 95.48(1), γ = 95.60(1)°, Z = 2) reveals the coordination of the NO2 group via N with a B1? N distance of 1.535(5) Å and an O2? N? O1 angle of 119.3(3)°. The 11B NMR spectrum exhibits the characteristic feature (1 : 1 : 4 : 4) of an apical monosubstituted B10 cluster with a strong downfield shift of the ipso-B atom at +13.4 ppm. The IR and Raman spectra show strong NO stretching vibrations at 1381 und 1420 cm?1. 相似文献
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The N2 laser excited fluorescence spectrum and the intensity of fluorescence of oxalyl chloride C2O2Cl2) condensed at 77°K either alone, or, diluted with a non-hydrocarbon or a hydrocarbon with dilution ratios ranging from 10 to 100 were studied. A slow condensation of the hydrocarbon matrix diluted sample showed a considerable reduction in the fluorescence intensity as compared to a fast condensation of the same sample. 相似文献
25.
Abstract The cyclopentylmethyl free radical has been generated in argon matrices by UV irradiation of the corresponding diacyl peroxide at T = 20K. The infrared spectrum of the radical reveals an out-of-plane deformation of the radical center at 563 cm?1 characteristic of primary alkyl radicals. 相似文献
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The infrared and Raman spectra of a platinum complex of the antiinflammatory drug piroxicam (Pir) and dimethylsulfoxide (DMSO) of composition [PtCl2Pir(DMSO)] were recorded and briefly discussed on the basis of its structural characteristics. The metal-to-ligand vibrations are analyzed in detail. 相似文献
28.
《Discrete Mathematics》2022,345(2):112676
The complete 3-uniform hypergraph of order v has a vertex set V of size v and the set of all 3-element subsets of V as its edge set. A tight 6-cycle is a hypergraph with vertex set and edge set . We show that there exists a decomposition of the complete 3-uniform hypergraph of order v into isomorphic copies of a tight 6-cycle if and only if , 2, 10, 20, 28, or . 相似文献
29.
Thomas Glonek 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):235-238
Abstract For pure sodium polyphosphates, Na n + 2P n O3n + 1, exhibiting 3 through 6 phosphorus atoms per molecule, the 31P chemical shift of the middle group phosphorus atoms as measured in aqueous solution (0.1 M in P) at pH 7 was seen to increase with increasing magnesium ion concentration until there was one Mg atom per polyphosphate molecule, after which the chemical shift decreased. Finally the rate of decrease diminishes and precipitation occurs. For the longer-chain phosphates, Na n + 2P n O3n + 1 with n = 8, 9, 10, or an average of 100, as well as for the ring phosphates, Na n P n O3n for n ranging from 3 through 10, an increase in magnesium concentration simply leads to a decrease in chemical shift which diminishes at the higher concentrations. These data lend additional support to the concept that polymerized phosphate anions in solution exist in preferred conformations which depend on the nature of the counteraction. 相似文献
30.
运用配位场理论方法获得了Ho3+离子低自旋4f95d组态的谱项和J-光谱多重态,根据电偶极跃迁选律合理地解析了LiYF4晶体中Ho3+离子在真空紫外区(120~160 nm)的吸收光谱,4个主要的吸收峰分别被归属为从基态(5I8)到Ho3+离子的低自旋4f95d组态的自旋允许跃迁。 相似文献