排序方式: 共有31条查询结果,搜索用时 15 毫秒
1.
H.G.C. Human N.P. Ferreira C.J. Rademeyer P.K. Faure 《Spectrochimica Acta Part B: Atomic Spectroscopy》1982,37(7):593-602
A method and computer program were developed for calculating the temperature of any part of a graphite furnace tube at any instant of time after onset of the heating cycle. Results for tubes of the Massman design show large differences in spatial temperature distributions during and at the end of the heating cycle when equilibrium is reached. When constant current is applied to contoured tubes, greater heating rates at the tube centres are obtained than with standard tubes. 相似文献
2.
Rademeyer CJ 《Analytical and bioanalytical chemistry》1996,355(5-6):581-584
The rotating disc nebulizer has been redesigned with respect to the principle parameters that determines its analytical performance. The flow pattern of the aerosol attained has been optimized by altering the shape of the inner chamber of the nebulizer to obtain optimum aerodynamic characteristics. The optimum angle of impact and "free flight" distance has been established using particle size distribution and mass transport efficiency as criteria. Analytical characteristics have been determined by monitoring the emission signal from aqueous standards. The accuracy has been assessed by using reference steel samples. Using standard solutions of different viscosity the performance of the nebulizer with respect to viscosity changes of the sample has been compared with that of a commercial Meinhardt nebulizer. The rotating disc nebulizer has been less affected by changes in viscosity making it possible to use this nebulizer with slurry and oil samples. 相似文献
3.
Changes to the fundamental and analytical parameters of a plasma have been investigated when ethanol has been added to aqueous or organic solutions. Excitation temperature, electron number density, and intensity of the H line increased when ethanol has been added to aqueous solutions, while an electron density decrease and signal reduction have been found when ethanol has been added to xylene. The sensitivity has been improved for all ethanol concentrations when water has been the solvent, but the reverse has been found for xylene solutions. 相似文献
4.
5.
Changes to the fundamental and analytical parameters of a plasma have been investigated when ethanol has been added to aqueous or organic solutions. Excitation temperature, electron number density, and intensity of the H(alpha) line increased when ethanol has been added to aqueous solutions, while an electron density decrease and signal reduction have been found when ethanol has been added to xylene. The sensitivity has been improved for all ethanol concentrations when water has been the solvent, but the reverse has been found for xylene solutions. 相似文献
6.
7.
The bimetallic carbocation complex [{Cp(CO)2Fe}2(μ-C4H7)]PF6 reacted with trifluoroacetic acid to give the mononuclear cationic complex [Cp(CO)2Fe{η2-(CH2CHCH2CH3)}]PF6, which formed yellow orthorhombic crystals in the space group P212121 with a = 7.652(4), b = 13.422(7), c = 14.037(7); α = β = γ = 90.00 and Z = 4. The carbocation is coordinated to the metal in a η2-fashion forming a chiral metallacyclopropane type structure. The β-CH carbon (C9) is disordered over two positions (C9A and C9B), each having about 50% occupancy. This is attributed to there being both the R and S enantioface isomers in equal amounts in the crystal sample. NMR data indicate that the metallacyclopropane structure observed in the solid state is preserved in solution. 相似文献
8.
9.
M. Rademeyer A. Lemmerer David G. Billing 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(7):m289-m292
The crystal structures of the two organic–inorganic hybrids bis(4‐aminopyridinium) hexachloridostannate(IV), (C5H7N2)2[SnCl6], and bis(p‐toluidinium) hexachloridostannate(IV), (C7H10N)2[SnCl6], differ in the way their cations pack in the layered structures. The Sn atom in the 4‐aminopyridinium compound lies on an inversion centre. 相似文献
10.