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991.
Xiao‐Zhi He Bao‐Yan Zhang Corresponding author Jian‐She Hu Mei Tian 《Liquid crystals》2013,40(3):299-306
In this work we prepared a nematic monomer (4′‐allyloxybiphenyl 4′‐ethoxybenzoate, M1 ), a chiral crosslinking agent (isosorbide 4‐allyloxybenzoyl bisate, M2 ) and a series of new side chain cholesteric liquid crystalline elastomers derived from M1 and M2 . The chemical structures of the monomers and polymers were confirmed by FTIR and 1H NMR spectroscopy. The mesomorphic properties were investigated by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy and X‐ray diffraction. The effect of the content of the crosslinking unit on phase behaviour of the elastomers is discussed. Polymer P1 showed a nematic phase, P2 –P7 showed a cholesteric phase; P6 formed a blue Grandjean texture over a broad temperature range 145–209.6°C, with no changed on the cooling. Polymers P4 –P7 , with more than 6?mol?% of chiral crosslinking agent, gave rise to selective reflection. Elastomers containing less than 15?mol?% of the crosslinking units displayed elasticity, reversible phase transition with wide mesophase temperature ranges, and high thermal stability. Experimental results demonstrated that, with increasing content of crosslinking agent, the glass transition temperatures first fell and then increased; the isotropization temperatures and mesophase temperature ranges decreased. 相似文献
992.
The alignment of nematic liquid crystals by rubbed polyimide surfaces has been well-studied and developed. A novel polyimide film which induced a homeotropic alignment of the nematic liquid crystal without rubbing or with weak rubbing strength was presented. However, there was a transition from homeotropic to planar alignment of the nematic liquid crystal after strong rubbing. In order to study the transition, the polyimide surface was investigated by atomic force microscopy, surface free energy measurement and angle-resolved analysis X-ray photo-electron spectroscopy before and after rubbing with a velvet fabric. It was found that both the change of surface polarity and surface morphology were not the reasons for the transition. The droop of the side chain on the polyimide surface after the rubbing treatment was detected by angle-resolved analysis X-ray photo-electron spectroscopy. Owing to the special structure of the novel polyimide, the X-ray photo-electron spectroscopy was successfully used for the first time to analyse the conformational change of the side chain of a polymer. In conclusion, the transition of nematic liquid crystal alignment from homeotropic to planar after rubbing was influenced by the side chain conformation of the polyimide. 相似文献
993.
Ya-na Liu Shu-fa Zhu Hui Tian Ming Zhou Juan Miao 《Plasma Chemistry and Plasma Processing》2013,33(4):737-749
Gliding arc discharge process was used for the treatment of methyl violet wastewater. First, the intermediate products were studied by gas chromatography coupled with mass spectrometry and Fourier transform infrared spectrometry, and ultraviolet–visible spectrometer. Second, the effects of inorganic anions including chloride (Cl?), carbonate (CO3 2?), sulfate (SO4 2?), phosphate (PO4 3?), nitrate (NO3 ?) on the degradation efficiency of methyl violet were examined. The research results indicated that hydroxyl radicals attacked carbon atom that situated in the center of dye molecule, and the conjugating structure of methyl violet was destroyed, and dye was degraded and decolored, so a possible degradation pathway was proposed by the analysis of intermediate products detected. The methyl violet degradation rate decreased with increasing anions concentrations, and their order of sequence according to the inhibition reaction was CO3 2? > Cl? > SO4 2? > NO3 ?. 相似文献
994.
A strain with urethanase activity was isolated from mouse gastrointestine. By combination of morphological characterization of the colony, hyphae, and spore and the sequence analysis of its rDNA ITS, the strain was determined as Penicillium variabile and named as P. variabile JN-A525. The enzymatic properties of urethanase from P. variabile JN-A525 were further studied. The optimum temperature and pH value of urethanase are of 50 °C and 6.0, respectively. The enzyme maintains stability when the temperature is below 50 °C and the pH is in the range of 7.0–10.0. The enzyme also exhibits ethanol tolerance. It can remove ethyl carbamate from Chinese rice wine without the change of flavor substances in the wine. 相似文献
995.
Chuan Jie Cheng Quan Lei Fu Xiong Xiong Bai Shao Jin Liu Liang Shen Wu Qin Fan Hong Xia Li 《Chemical Papers》2013,67(3):336-341
A novel cationic gemini surfactant has been readily synthesised in 70 % total yield. The functional gemini surfactant can act both as an emulsifier and an atom transfer radical polymerisation (ATRP) initiator in mini-emulsion polymerisation of methyl methacrylate (MMA), in which no other emulsifier was required. 1-(Dimethylamino)dodecane (N,N-dimethyldodecylamine, DMDA) was found to be a good ligand in the activator generated by electron transfer (AGET) ATRP reaction. Kinetic studies indicated that the polymerisation featured controlled/living radical polymerisation. 相似文献
996.
Fan Yang Hongmei Yang Baozhu Tian Jinlong Zhang Dannong He 《Research on Chemical Intermediates》2013,39(4):1685-1699
Mo and C co-doped TiO2 photocatalysts were successfully prepared by a calcination–hydrothermal method. The catalysts were characterized by XRD, XPS, DRS, FTIR, and Raman spectroscopy. Results from photocatalysis showed that 1%Mo–C4/TiO2 had excellent visible light photocatalytic activity. This may be ascribed not only to the Mo and C doping but also to synergism between the Mo and C. 相似文献
997.
Chang Jun Zou Quan Wu Tang Gui Hong Lan Qiang Tian Tai Yu Wang 《Journal of inclusion phenomena and macrocyclic chemistry》2013,76(1-2):61-68
For the first time, hydroxypropyl-β-cyclodextrin (HP-β-CD) has been brought in to include 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) in order to enhance inhibition efficiency of PBTCA, which leads a new approach to study oil–gas field corrosion inhibition in the process of acid treatment. Based on the host–guest inclusion reaction, the inclusion complex of PBTCA with HP-β-CD has been prepared in the laboratory. UV–Vis absorption spectrum was applied to study the inclusion behavior of PBTCA with HP-β-CD. The results revealed that PBTCA with HP-β-CD can form a 1:1 stoichiometry inclusion complex. The 1:1 inclusion complex synthesized by using lyophilization was further characterized by Fourier transform infrared spectroscopy. Besides, inhibition effect of the inclusion complex on the corrosion inhibition of Q235 carbon steel has been investigated in 0.1 M sulfuric acid (H2SO4) solution using potentiodynamic polarization, electrochemical impedance spectroscopy techniques and scanning electron microscopy (SEM). It was found that the presence of the inclusion complex better achieved the anti-corrosion property in aggressive medium than was the case with alone PBTCA and the highest inhibition efficiency of the inclusion complex over 90 % was obtained, which are suggestive of the active effect of the inclusion complex for improving inhibition efficiency of PBTCA. Meanwhile, the results obtained from SEM further showed that the inclusion complex acts as a more efficient corrosion inhibitor for Q235 carbon steel in H2SO4 medium. 相似文献
998.
Dongmei Li Zhongzhen Tian Zhiping Xu Gaolei Wang 《Research on Chemical Intermediates》2013,39(5):2063-2070
1,3-Dithiolane-containing nitromethylene derivatives, as candidates for screening as neonicotinoid insecticides, were synthesized by reaction of compound (4) with 1,2-ethanedithiol. Compounds 7a–g were obtained via Mannich reaction of (E)-1-((1,3-dithiolan-2-yl)methyl)-2-(nitromethylene)imidazolidine (6), primary amines and formaldehyde. The synthesized compounds were identified by 1H NMR, IR spectroscopy and elemental analysis. Preliminary bioassays indicated that most of the compounds had moderate insecticidal activity against Aphis craccivora. The relationship between molecular structure and biological activity is discussed. 相似文献
999.
Yong Li Xia Wen Lei Li Feng Wang Ning Zhao Fukui Xiao Wei Wei Yuhan Sun 《Journal of Sol-Gel Science and Technology》2013,66(3):353-362
A one-pot template-free route was developed for the synthesis of novel tetraethylenepentamine modified porous silica as CO2 adsorbents, the obtained materials were characterized by N2 adsorption/desorption, thermogravimetry, elemental analysis, Fourier transform infrared spectrometry,scanning electron microscopy and transmission electron microscopy. It was found that the amine species were inserted into the silica skeleton, which considerably enhanced their dispersion. Compared with similar materials derived from impregnation, the porous structure of the silica can be better reserved, leading to a promising CO2 adsorption capacity of 3.98 mmol CO2/g-adsorbent and a fast adsorption kinetic in simulated flue gas at 348 K. The resulted adsorbents could also be easily regenerated and showed a good durability in multiple adsorption–desorption cycles. All these features make this method a promising option for the preparation of CO2 adsorbents. 相似文献
1000.
Junsong Yang Juanjuan Zhao Hailong Wang Shengyi Zhang Jiming Song Changjie Mao Helin Niu Baokang Jin Yupeng Tian 《Journal of Sol-Gel Science and Technology》2013,67(3):660-664
By dipping-lifting in sol–gel solution and reducing process, the TiO2 composite film on the glass plate was first prepared. Then, the PbSe/BaTiO3/TiO2 composite film was fabricated by interface reaction with BaTiO3 and PbSe on the surface of TiO2 composite film. The characterization results show that the uniform porous TiO2 film is made up of the anatase crystal, and the PbSe/BaTiO3/TiO2 composite film is constructed by doping or depositing BaTiO3 and PbSe nanoparticles on the surface of TiO2 film. The photoelectrochemical measurement results indicate that the PbSe/BaTiO3/TiO2 composite film has an interesting photoelectrochemical conversion property. 相似文献