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61.
Cheng-Fang Qiao Qing Wei Zheng-Qiang Xia Chun-Sheng Zhou San-Ping Chen 《Journal of Thermal Analysis and Calorimetry》2012,107(2):527-533
Six lanthanide compounds [Ln(H2O)9](m-BDTH)3·9(H2O) where Ln = La (1), and [Ln(H2O)8](m-BDTH)3·9(H2O) (m-BDTH2 = 1,3-benzeneditetrazol-5-yl) where Ln = Lu (2), Yb (3), Er (4), Ho (5) and Y (6) were hydrothermally synthesized and characterized by elemental analyses, infrared spectra, powder X-ray diffraction (PXRD) and X-ray single crystal diffraction. PXRD indicates that 2–6 are isomorphous. Structural analyses reveal that 1 is coordinated by nine water molecules forming a capped-square antiprism, while 2–6 are coordinated by eight water molecules forming a simple square antiprismatic geometry. Effects of water molecules on thermal stability were also discussed by thermogravimetric (TG), DSC, and PXRD under different temperatures. TG analyses suggest that 1 loses lattice and coordinated water molecules with no diacritical boundary, and 6 removes lattice water molecules first and then coordinated water molecules. DSC and PXRD further confirm the consequence. 相似文献
62.
63.
In this paper, we propose a novel image recompression frame?work and image quality assessment (IQA) method to efficient?ly recompress Internet images. With this framework image size is significantly re... 相似文献
64.
65.
This article presents an original work aimed at rationally designing molecularly imprinted polymer (MIP) toward a high specific adsorbent. Assembling with cobalt as the pivot, the MIP was prepared by coordinating polymerizable monomers around an inducible template. The use of pivot obviously plays a positive role on increasing the specificity of MIP, so as to adsorb more for the template and less for its analogue. Related studies indicate that these may be a result of increasing specific interaction, which makes the MIP capable of recognizing the imprint species. Further information from thermodynamic analysis reveals that the increasing specific interaction, in logic, can be due to a higher fidelity of imprint, which specifically allures the template to bind. 相似文献
66.
Fangqiang Fan Zhengbin Xia Qingying Li Zhong Li Huanqin Chen 《Journal of Thermal Analysis and Calorimetry》2013,114(3):937-946
Phosphorus-containing styrene–acrylic copolymers are synthesized by free radical seeded emulsion polymerization with the monomers of MMA/St/BA/MAA and phosphorus-containing vinyl monomer (SIPOMER PAM100). The properties of copolymer films are characterized by water adsorption test, thermogravimetry, Fourier transform infrared spectroscopy (FTIR), and energy dispersive spectroscopy (EDS), etc. The copolymer emulsions are used as the binder in an intumescent coatings formulation, and the fire-retardant performances of the coatings are determined by an instrument which the furnace temperature is analoging the cellulose fire temperature. The water adsorption of copolymer film increases remarkably owing to the increasing of phosphoric acid group in the polymer chain. The thermal decomposition stability and thermal-oxidative decomposition stability of the copolymer are improved when PAM100 is introduced into its chain, which is strongly supported by the FTIR and EDS results of copolymer residual treated at different temperature. The EDS results also illustrate that the fire retardancy enhanced by PAM100 during combustion owing to the condensed-phase mechanism. The fire-retardant test results show that the intumescent coatings using StA-P1.5 copolymer emulsion as the binder obtains the best fire retardant performance. We suggested that StA-P1.5 presents the lower reactivity with the acid source (APP) in 275–400 °C, and the higher reactivity with APP when the temperature is greater than 500 °C would be benefit for the swelling–charring process and the final fire retardant performance. The exorbitant crosslinking in StA-P7 brings a negative effect on the fire-retardant performance of intumescent coatings, even if it introduces a densy swollen char layer. 相似文献
67.
An approximate method has been established to calculate the depth of the potential acting on an electron in a molecule at the saddle point along a chemical bond, denoted by Dpb. It is a new indicator which can be used for predicting the strength of a chemical bond. In this work, as a practical application for demonstrating thismethod, we calculated the Dpb of deoxyribonucleosides and ribonucleosides along all C-H and N-H chemical bonds using the method. The results are in fair agreement with those results of previously reported experimental and theoretical observations. 相似文献
68.
Qiongbo Zhou Xuzhuo Sun Haibo Zhang Chunlan Xia Xiaohai Zhou 《Journal of Cluster Science》2013,24(4):969-977
A crystal structure of {H2O@CB[5]·(NH4PF6)2}·9(H2O) which consists of supramolecular chains self-assembled by water clusters and water capsules alternately was demonstrated. A water molecule is encapsulated in the cavity of CB[5] whose portals are occupied by two NH4 +, resulting in the formation of water capsule. The water clusters are made up of (H2O)4 and (H2O)5 clusters. The (H2O)4 cluster forms zigzag line and (H2O)5 features “Y-shape” structure. Moreover, anion channels consisting of six parallel supramolecular chains are occupied by PF6 ?. 相似文献
69.
Wen-Yan Ji Xiao-Li Xia Xiao-Hui Ren Fang Wang Hai-Jun Wang Kai-Sheng Diao 《Structural chemistry》2013,24(1):49-54
Ab initio calculations have been performed on the complexes of CF2Cl2 with NO and SO2, and a set of stable configurations for CF2Cl2–NO and CF2Cl2–SO2 were found with no imaginary frequencies by the MP2 method. In addition, the binding energy and the NBO analysis were used to evaluate the relative stability of the complexes. The calculated results indicate that the weak interactions in the CF2Cl2–NO and CF2Cl2–SO2 systems involved are enhanced with the increase of the number of non-covalent bonds. Further studies predict that the CF2Cl2–SO2 system may play a more important role than the CF2Cl2–NO system in environmental problem because the former offers a stronger interaction than the latter. Furthermore, the non-covalent binding interactions of Cl···N and Cl···O for CF2Cl2–NO system, Cl···O, Cl···S and F···S for CF2Cl2–SO2 system, are the dominant forces, which seem to be very significant as a driving force influencing the arrangement of molecules, especially in CF2Cl2–SO2 system. 相似文献
70.
A novel way of preparation for o-hydroxyarylketones with mild conditions and good yields by palladium-catalyzed coupling reaction of o-hydroxyarylaldehydes with hypervalent iodonium salts via the cleavage of the aldehyde C-H bond has been reported. 相似文献