Multidimensional Gas Chromatography–Mass Spectrometry Method for Fingerprinting Polycyclic Aromatic Hydrocarbons and Their Alkyl-Homologs in Crude Oil

The composition of polycyclic aromatic hydrocarbons in crude oil is usually too complex to use standard capillary gas chromatography to separate all of the components. In this study, a multidimensional gas chromatography–mass spectrometry (GC-MS) technique was used to analyze polycyclic aromatic hydrocarbon fractions of crude oil collected from the Dongying oil field in the Bohai Sea. A DB-17MS column (30?m?×?0.25?mm?×?0.25?µm) was used as a prefractionating column and only selected heart-cuts were transferred to the second chromatographic dimension (HP-5MS, 15?m?×?0.25?mm?×?0.25?µm) by a pressure-adjusted continual flow-type switching device for quantification of the polycyclic aromatic hydrocarbons. The chromatographic elements and parameters, such as detector selection and column combinations, were optimized. Naphthalene, phenanthrene, fluorene, dibenzothiophene, chrysene, and their C₁–C₄ alkyl homologs were identified. The profile of the polycyclic aromatic hydrocarbons obtained using the multidimensional GC-MS method was compared with the results obtained by traditional one-dimensional GC-MS.     

Calorimetric studies on the electrorefining process of copper

Calorimetric measurements were carried out on the electrorefining of copper using different current densities with a Calvet type microcalorimeter at room temperature. The ratio (R) of the measured heat (Q _m orW _m) to the input electric energy (Q _in orW _in) and the excess heat (Q _ex orW _ex), i.e. the difference betweenQ _m (orW _m) andQ _in (orW _in) during the electrorefining process were discussed in terms of general thermodynamics. It was found thatR andQ _ex were related to the current density employed in the experiment and varied as a logarithmic function. The results obtained here indicate that the heat generation under different conditions, such as different currents or voltages, may be caused partially by the irreversibility of the process or by some unknown processes.Dedicated to Prof. Menachem Steinberg on the occasion of his 65th birthdayThe authors would like to acknowledge the extreme encouragements and help of Professor Shuyi Liu (University of Science and Technology of China) and Professors Fu Tan and Guoquan Liu (Institute of Chemistry, Academia Sinica).This study was supported by the National Nature Science Foundation of China.     

Excess molar enthalpies for binary mixtures of trimethyl phosphate with alkanols {CH3(CH2)nOH, n = 0–3} at 298.15 K

The excess molar enthalpies () for the binary mixtures of trimethyl phosphate (TMP) with alkanols {CH₃(CH₂)_nOH, n = 0–3} have been measured with an isothermal calorimeter at 298.15 K and atmospheric pressure. The values are positive for all the mixtures over the whole composition range. The values increase in the order methanol < ethanol < 1-propanol < 1-butanol. The experimental results have been correlated with the Redlich–Kister equation.     

关于测定二元系中挥发组分活度系数的GLPC方法的研究

GLPC法测定二元系中挥发组分有限浓度时的活度系数曾为Chueh和Ziegler、Conder和Purnell、Chch和Parcher等所探讨,但因后续工作太少,迄今未能成熟,将这一方法得到肯定,对于研究二元溶液的热力学是有意义的,经过反复比较,我们决定对Chueh和Ziegler的方法作进一步探讨。     

Fabrication of self-assembled ultrathin photochromic films containing mixed-addenda polyoxometalates H5[PMo10V2O40] and 1,10-decanediamine

A layered phosphovanadomolybdate/1,10-decanediamine (1,10-DAD) self-assembled ultrathin film was fabricated by means of alternating adsorption of mixed-addenda polyoxometalates (POMs) (phosphovanadomolybdate, H₅[PMo₁₀V₂O₄₀]) and 1,10-DAD, and its photochromic properties were investigated. It is found that the self-assembled multilayer (SAM) film shows high-photochromic response, excellent photochromic stability and reversibility. The photochromic behavior of the SAM is closely related to the reduction potentials of addenda atoms in mixed-addenda POMs. In the case of photo-reduced mixed-addenda POMs, the electron is localized on the more reducible atom, and the addenda atoms with higher reduction potentials show prior photochromism compared with those with lower reduction potentials. The coloration speed is improved after introduction of V into molybdenum POM. The well-ordered lamellar structure of the film was well maintained during the coloration.     

Addition of Hydrogen or Ammonia to a Low‐Valent Group 13 Metal Species at 25 °C and 1 Atmosphere

Mild‐mannered : The low‐valent aryl gallium(I) species :GaAr′ (Ar′=2,6‐(2,6‐iPr₂C₆H₃)₂C₆H₃) undergoes addition to H₂ or NH₃ at room temperature and one atmosphere of pressure to afford 1 or 2 (see scheme), which were characterized by X‐ray crystallography and NMR and IR spectroscopy.

     

一种新型的甲酸/铁离子燃料电池

以甲酸为燃料、 Fe³⁺为氧化剂组成了一种新型的甲酸/铁离子燃料电池, 阳极催化剂为多壁碳纳米管(MWCNT)或β-环糊精修饰的MWCNT(β-CD-MWCNT)负载的金属钯或钯锡纳米颗粒: PdSn/MWCNT, Pd/β-CD-MWCNT和PdSn/β-CD-MWCNT. 运用循环伏安(CV)和计时电流(CA)等技术研究了各催化剂在碱性条件下对甲酸氧化反应的电催化活性. 结果表明, 加入适量的金属锡能促进钯对甲酸的电催化氧化, 甲酸氧化电位提前, 电流密度增加; 环糊精的改性对催化剂电催化活性有一定提升. 将上述催化剂制成电池阳极片, 碳粉制成电极阴极片, 组成甲酸/铁离子燃料电池并测试其放电性能. 结果表明, 电池的开路电压在0.981.20 V之间; 以PdSn/β-CD-MWCNT为阳极时, 其最大放电电流密度达50 mA/cm², 最大功率密度达12.6 mW/cm², 远优于以Pd/C为阳极的电池性能.     

Separation of spin angular momentum in space-variant linearly polarized beam

We show that the spin angular momentum (SAM) flux in a space-variant linearly polarized beam can be separated in the focal plane. Such a beam carries only orbital angular momentum (OAM) and develops a net SAM flux upon focusing. The radial splitting of the SAM flux density is mediated by the phase vortex (or OAM) and can be controlled by the topological charge of the phase vortex. Optical trapping experiments verify the separation of the SAM flux density. The proposed approach enriches the manipulation of the angular momentum of light fields and inspires more designs of focus engineering, which would benefit optical micromanipulation of microscopic particles.     

Preparation and photocatalytic activity of magnetic samarium-doped mesoporous titanium dioxide at the decomposition of methylene blue under visible light

Preparation of samarium-doped mesoporous titanium dioxide (Sm/MTiO₂) coated magnetite (Fe₃O₄) photocatalysts (Sm/MTiO₂/Fe₃O₄) and their activities under visible light were reported. The catalysts with Sm/MTiO₂ shell and a Fe₃O₄ core were prepared by coating photoactive Sm/MTiO₂ onto a magnetic Fe₃O₄ core through the hydrolysis of tetrabutyltitanate (Ti(OBu)₄, TBT) with precursors of Sm(NO₃)₃ and TBT in the presence of Fe₃O₄ nanoparticles. The morphological, structural and optical properties of the prepared samples were characterized by BET surface area, transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis absorption spectroscopy. The effect of Sm ion content on the photocatalytic activity was studied. The photocatalytic activities of obtained photocatalysts under visible light were estimated by measuring the decomposition rate of methylene blue (MB, 50 mg/L) in an aqueous solution. The results showed that the prepared photocatalyst was activated by visible light and used as effective catalyst in photooxidation reactions. In addition, the possibility of cyclic usage of the prepared photocatalyst was also confirmed. Moreover, Sm/MTiO₂ was tightly bound to Fe₃O₄ and could be easily recovered from the medium by a simple magnetic process. It can therefore be potentially applied for the treatment of water contaminated by organic pollutants.     

Photocatalytic Activity of Fe and Ce Co‐doped Mesoporous TiO2 Catalyst under UV and Visible Light

The catalysts of un‐doped, single‐doped and co‐doped mesoporous titanium dioxide (MTiO₂) were prepared by a template method with tetrabutyltitanate (Ti(OC₄H₉)₄) as a Ti source material and Pluronic P123 as a template. The photo‐absorbance of the obtained catalysts was measured by UV‐vis absorption spectroscopy, and the photocatalytic activities of the prepared samples under UV and visible light were estimated by measuring the degradation rate of methyl orange (MO) (50 mg/L) in an aqueous solution. It was shown that the co‐doped MTiO₂ could be activated by visible light and could thus be used as an effective catalyst in photo‐oxidation reactions. The effect of Fe and Ce co‐dopants on the material properties was investigated by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and N₂ adsorption‐desorption isotherm measurement. The characterizations indicated that the photocatalysts possessed a homogeneous pore diameter of ca. 10 nm with high surface area of ca. 150 m²/g. The photocatalytic activity of MTiO₂ co‐doped with Fe and Ce was markedly improved due to the synergistic actions of the two dopants.