| Thesis Name：Novel red phosphors for solid-state lighting: the system NaM(WO4)2−x(MoO4)x:Eu3+ (M=Gd, Y, Bi) |
| Country：[CN] |
Usage：[Novel red phosphors] |
| Remarks： |
Solid solutions of tungstate and molybdate scheelites of formula NaLn(WO4)2−x(MoO4)x and NaY1−yBiy(WO4)2 (Ln = Y, Gd) doped with Eu3+ ion have been synthesized by solid-state reactions. Red luminescence is obtained in these samples on excitation either in the charge-transfer band or Eu3+ levels. In particular, intense red emission is obtained by exciting at ~394 nm using the sharp 7F0→5L6 line of Eu3+. These materials could find applications as red phosphors for white lighting devices utilizing GaN-based excitation in the near UV.
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| Thesis Name：Gas-phasereactions for selective detection of the explosives TNT and RDX |
| Country：[CN] |
Usage：[Detecting explosives] |
| Remarks： |
Highly selective gas-phase reactions with ethyl vinyl ether (EVE) of major electron (EI) and chemical ionization (CI) fragment ions of the explosives TNT and RDX have been uncovered. The fragment ion of m/z 210 from TNT undergoes [4++ 2] cycloaddition with EVE to form an oxo-iminium ion of m/z 282, which dissociates by acetaldehyde loss after a [1,5-H] shift to form a quinolynium ion of m/z 238. The fragment ion of m/z 149 from RDX reacts with EVE by a formal vinylation reaction, that is, the elusive cyclic adduct loses ethanol to yield a nitro-iminium ion of m/z 175, which reacts further with EVE to form a second cyclic product ion of m/z 247. Calculations and MS/MS experiments support the proposed structures. These highly characteristic reactions of diagnostic EI and CI fragment ions improve selectivity for TNT and RDX detection. |
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| Thesis Name：A review of desulfurization of light oil based on selective oxidation |
| Country：[CN] |
Usage：[desulfurization of light oil] |
| Remarks： |
Environmental concerns have driven the need to remove sulfur-containing compounds from light oil. Oxidative desulfurization has been given much interests recently due to its mild condition and without H2. In this paper, the mechanism, process, and development of selectively oxidative desulfurization are reviewed.It also introduced the application of the oxidative desulfurization in different kinds of light oils. In the end, the authors point out the further research needed to be worked on in this field.
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| Thesis Name：Progress of the research on the thermostability of heteropoly compounds |
| Country：[CN] |
Usage：[the thermostability of heteropoly compounds] |
| Remarks： |
In this paper, the factors influencing the thermostability of heteropoly compounds were reviewed, such as external cation including organic cation, alkaline-earth metals cation, alkali metals cation, transition metals cation and rare-earth metals cation as well as internal heteroatoms including transition metal and nonmetal atoms. |
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| Thesis Name：Determination of aromatic sulfonated compounds by reversed-phase ion-pair chromatograohy with tetramethylene-oxide as organic modifier |
| Country：[CN] |
Usage：[A reversed-phase ion-pair chromatography method wi] |
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A reversed-phase ion-pair chromatography method with ammonium tetrabutyl bromide as ion-pairing reagent and UV detection has been developed for aromatic sulfonated compounds. It was testified that the concentration of ion pair reagent, pH and the volume ratio of tetramethylene-oxide in mobile phase played important roles in the separation. Linearity regression equations along with linearity ranges, correlation coefficients of 0.9991-0.9996 and detection limit for determination of seven sulfonated compounds were offered. To achieve the detection of analytes in low concentration water samples, the ion-pair extraction technique was employed with ammonium tetrabutyl bromide (TBA) as ion-pair reagent and dichloromethane as extractant. Recoveries of the method were between 96.8 and 101.7%, and relative standard deviation was below 7.6%. Different concentration of 3-nitro-benzenesulfonate, dibenzal-4-sulfonate and methyl orange were detected from rainwater, tap water and electrodialysised water sample, respectively |
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| Thesis Name：Study on extraction methods of triazophos in sediments |
| Country：[CN] |
Usage：[Methods of extracting triazophos residue in sedime] |
| Remarks： |
Methods of extracting triazophos residue in sediments were studied. The results showed that the extraction with hexane and water, and assisted with magnetic stirring, was effective. Triazophos in the extracts was determined by gas chromatography with flame photometric detector (GC-FPD). The recovery of triazophos with the established method was within the range of 87-95% and the relative standard deviation (RSD) was 4.3% (n=3). The linearity was between 0.01-1.0mg/kg. with the correlation coefficient of 0.9994. The method detection limit (MDL) of triazophos was 3.0μg/kg d.w. The study also showed that triphenyl phosphate could be adopted as surrogate for data quality control. Finally, the method was applied to determine triazophos in 2 sediment samples.
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| Thesis Name：Study on solid phase extraction and spectrophotometric determination of cadmium with 2-(2-quinolinylazo)-4-methyl-1,3-dihydroxybenzene |
| Country：[CN] |
Usage：[The color reaction of 2-(2-quinolinylazo)-4-methyl] |
| Remarks： |
The color reaction of 2-(2-quinolinylazo)-4-methyl-1,3-dihydroxidebenzene (QAMDHB) with cadmium was studied. In the presence of pH=8.0 buffer solution and TritonX-100 medium, QAMDHB can react with cadmium (II) to form a stable 2:1 complex (QAMDHB: Cd(II)). The molar absorptivity is 1.01×105 L.mol-1.cm-1 at 560 nm. Beer's law is obeyed in range of 0-1.0 mg/ml. The cadmium ion in samples can be enriched and separated by solid phase extraction with anion exchange resin cartridge. This method was applied to the determination of cadmium in water and food with good results.
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| Thesis Name：Preparation of TiO2 thin films by modified sol-gel method |
| Country：[CN] |
Usage：[organic-inorganic hybrid TiO2 sol] |
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An organic-inorganic hybrid TiO2 sol was prepared by in-site polymerization (Pechini’s method) and was coated onto a glass substrate by dip-coating. The TiO2 thin films were heat-treated at different temperature. The obtained films were characterized by UV-Vis, XRD and AFM. It showed that the crystal structure of the TiO2 thin films is Anatase, and the crystal particle size of TiO2 is about 40-50nm by observation of the images of AFM .The photocatalytic properties of the film were investigated by measuring the photodegradation oxidation of methyl orange under UV irradiation condition. The photocatalytic activity of the film is higher than that of the Degussa P-25 film under the same condition.
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| Thesis Name：Chemical bond and thermoelectric properties of Ca3Co2O6 and Ca3Co4O9 |
| Country：[CN] |
Usage：[the thermoelectric performance of oxide compoun] |
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The relation between electronic structure, chemical bond and thermoelectric property of Ca3Co2O6 and Ca3Co4O9 is studied by using density function and discrete variation method(DFT-DVM). The gaps between the highest valence band (HVB) and the lowest conduction band(LCB) of Ca3Co2O6 and Ca3Co4O9 both show the semiconductor property, and the gap of Ca3Co4O9 is less than that of Ca3Co2O6. Co 3d and O 2p mainly contribute to HVB and LCB near Fermi level, but there is obvious difference between Ca3Co2O6 and Ca3Co4O9. The Co-O covalent and ionic bonds of Ca3Co4O9 are both stronger than those of Ca3Co2O6. Ca plays the role of connections between the chains of ...... -Co(1)O3-Co(2)O3- ...... in Ca3Co2O6, and between CoO2 and Ca2CoO3 layers in Ca3Co4O9. The component of Ca also can decrease ionic and covalent bond strength and prove the thermoelectric property.
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| Thesis Name：Group transfer polymerization through the phosphoniosilylation reaction |
| Country：[CN] |
Usage：[phosphoniosilylation reaction] |
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The reactions of trimethylsilyldiphenylphosphine(TMSDPP) with ethyl acrylate(EA) and methyl methacrylate(MMA) were studied respectively. When TMSDPP reacted with EA, the processes of 1,2- and 1,4- addition were observed, resulting in the complicated products. As for the reaction of TMSDPP with MMA, the mechanism was mainly 1,4- addition. At 0ºC, EA as monomer, the group transfer polymerization initiated by TMSDPP directly could not be carried out. While MMA as monomer, the functional polymer, lacking of molecular weight control, could be obtained. When the reaction temperature droped to -30ºC, it showed that the group transfer polymerization of MMA could be controlled , and the star poly(methyl methacrylate) containing diphenylphosphine as a terminal group was synthesized |
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