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151.
用XPS研究兖州煤各显微组分中有机硫存在形态 总被引:11,自引:0,他引:11
应用XPS(X射线光电子能谱)法研究了兖州煤显微组有机硫的存在形态。按密度不同分离出的兖州煤中各显微且分内的有机硫存在形态是有差异的。据XPS分析,稳定组中含有大量的硫砜、硫醚含硫化合物,噻吩型硫闪之;镜质组中硫、硫醚与脂肪族硫化物含量相当;惰性组中噻吩型硫与硫醚和硫醇型硫各占有机硫的一半。噻吩型硫在充州煤各显微组分中,随密度增加。含量有所减少,硫醚、硫醇及二硫化物的含量也有类似的趋势。这些结果将 相似文献
152.
在隔离式是电解中,用泡沫铅作用阴极,铂作阳极,饱和甘汞电极做参考电极,对太原钢铁公司焦化厂煤沥青经溶剂萃取后所得的精制沥青进行了电化学加氢的研究,考察了电解体系工艺条件对加氢效果的影响。 相似文献
153.
154.
Lebedev B. V. Kulagina T. G. Smirnova N. N. Shifrina Z. B. Averina M. S. Rusanov A. L. 《Journal of Thermal Analysis and Calorimetry》2003,74(3):735-748
In an adiabatic vacuum calorimeter, the temperature dependence of the heat capacity C
p of phenylated polyphenylene and initial comonomer 1,4-bis(2,4,5-triphenylcyclopentadienone-3-yl)benzene was studied between
6 and 340 K with an uncertainty of about 0.2%. In a calorimeter with a static bomb and an isothermal shield their energies
of combustion DUcomb were measured. From the experimental data, the thermodynamic functions C
p
0 (T), H
0(T)-H
0(0), S
0(T)-S0(0), G
0(T)-H
0(0) were calculated from 0 to 340 K, and standard enthalpies of combustion ΔH
comb
0 and thermodynamic parameters of formation-enthalpies ΔH
f
0, entropies ΔH
f
0, Gibbs functions ΔG
f
0 - of the substances studied were estimated at T=298.15 K at standard pressure. The results were used to calculate the thermodynamic characteristics (ΔH
f
0 ,ΔS
f
0, ΔG
f
0) of phenylated polyphenylene synthesis in the range from 0 to 340 K.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
155.
H. Morais C. Ramos E. Forgasc T. Cserháti N. Matos V. Almeida J. Oliveira 《Chromatographia》2002,56(1):S173-S175
Summary The extractability and stability of anthocyanins from the skins ofVitis vinifera were determined at different pH values. Anthocyanins were extracted using acetone, partitioned with chloroform and pre-purified
by solid-phase extraction (SPE). They were analysed by RP-HPLC, and the kinetic parameters of decomposition were calculated.
The total monomeric anthocyanin content was determined by spectrophotometry. Anthocianins were well separated by RP-HPLC.
The efficiency of extraction depended strongly on the pH of the extracting agent and on the character of the pigment to be
extracted. The amount of anthocyanins decreased with increasing duration of storage, more so at elevated temperatures.
Presented at Balaton Symposium '01 on High-Performance Separation Methods Siófok, Hungary, September 2–4, 2001. 相似文献
156.
Fatma M. Elzawawy 《Monatshefte für Chemie / Chemical Monthly》1991,122(11):921-925
Summary The stoichiometric stability constants for La(III) and Y(III)L-serine complexes were determined by potentiometric methods at different ionic strengths adjusted with NaClO4 and at different temperatures. The overall changes in free energy (G
o), enthalpy (H
o), and entropy (S
o) during the protonation ofL-serine and that accompanying the complex formation with the metal ions have been evaluated.
Komplexbildungskonstanten und thermodynamische Parameter für La(III)- und Y(III)-L-Serin-Komplexe
Zusammenfassung Die stöchiometrischen Komplexbildungskonstanten für La(III)- und Y(III)-L-Serin-Komplexe wurden mittels potentiometrischer Methoden bei verschiedenen Ionenstärken (mit NaClO4 adjustiert) und bei verschiedenen Temperaturen bestimmt. Die Änderungen in der freien Energie (G o), Enthalpie (H o) und Entropie (S o) während der Protonierung und der Komplexbildung mit den Metallionen wurden ermittelt.相似文献
157.
158.
The conditions of formation of complex lanthanide chromate(VI)-phosphates K2R(CrO4)(PO4) were found and these compounds were synthesized by solid-state synthesis with variation of the starting compounds, the temperature
of synthesis (500–800 °C), and the annealing time (6–200 h). These salts are typical of late lanthanides, R = Dy-Lu, Y. Using
lutetium derivatives as examples, it was shown that no similar compounds with lithium or sodium are formed. All the complex
chromate(VI)-phosphates obtained decompose under static conditions at temperatures above 550 °C. They are isostructural and crystallize
in the monoclinic system. The unit cell parameters for thulium, ytterbium, and lutetium compounds were calculated. It is shown
by IR spectroscopy that PO4 tetrahedra in the crystal lattice of potassium lanthanide chromate(VI)-phosphates are substantially distorted, whereas the CrO4 tetrahedra retain the regular tetrahedron symmetry (T
d
).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 622–626, April, 2006. 相似文献
159.
Dhanpat Rai Dean A. Moore Nancy J. Hess Kevin M. Rosso Linfeng Rao Steve M. Heald 《Journal of solution chemistry》2007,36(10):1261-1285
Chromium(III)-carbonate reactions are expected to be important in managing high-level radioactive wastes. Extensive studies
on the solubility of amorphous Cr(III) hydroxide solid in a wide range of pH (3–13) at two different fixed partial pressures
of CO2(g) (0.003 or 0.03 atm.), and as functions of K2CO3 concentrations (0.01 to 5.8 mol⋅kg−1) in the presence of 0.01 mol⋅dm−3 KOH and KHCO3 concentrations (0.001 to 0.826 mol⋅kg−1) at room temperature (22±2 °C) were carried out to obtain reliable thermodynamic data for important Cr(III)-carbonate reactions.
A combination of techniques (XRD, XANES, EXAFS, UV-Vis-NIR spectroscopy, thermodynamic analyses of solubility data, and quantum
mechanical calculations) was used to characterize the solid and aqueous species. The Pitzer ion-interaction approach was used
to interpret the solubility data. Only two aqueous species [Cr(OH)(CO3)22− and Cr(OH)4CO33−] are required to explain Cr(III)-carbonate reactions in a wide range of pH, CO2(g) partial pressures, and bicarbonate and carbonate concentrations. Calculations based on density functional theory support
the existence of these species. The log 10
K° values of reactions involving these species [{Cr(OH)3(am) + 2CO2(g)⇌Cr(OH)(CO3)22−+2H+} and {Cr(OH)3(am) + OH−+CO32−
⇌Cr(OH)4CO33−}] were found to be −(19.07±0.41) and −(4.19±0.19), respectively. No other data on any Cr(III)-carbonato complexes are available
for comparisons. 相似文献
160.
M. V. Kök 《Journal of Thermal Analysis and Calorimetry》2005,79(1):175-180
Differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG) has been used to obtain information on the temperature-controlled combustion characteristics of seventeen coals of different origin from Thrace basin of Turkey. Experiments were performed in air atmosphere up to 600°C at a heating rate of 10°C min-1. The DSC/TG curves clearly demonstrate distinct transitional stages in the entire coal samples studied. Reaction intervals, peak and burn-out temperatures of the coal samples are also determined. Two different kinetic methods known as, Arrhenius and Coats-Redfern, were used to analyze the kinetic data and the results are discussed. 相似文献