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991.
The enthalpy change of formation of the reaction of hydrous dysprosium chloride with ammonium pyrrolidinedithiocarbamate (APDC) and 1,10-phenanthroline (o-phen?H2O) in absolute ethanol at 298.15 K has been determined as (-16.12 ± 0.05) kJ?mol-1 by a microcalormeter. Thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), rate constant and kinetics parameters (the apparent activation energy, the pre-exponential constant and the reaction order) of the reaction have also been calculated. The enthalpy change of the solid-phase reaction at 298.15 K has been obtained as (53.59 ± 0.29) kJ?molt-1 by a thermochemistry cycle. The values of the enthalpy change of formation both in liquid-phase and solid-phase reaction indicated that the complex could only be synthesized in liquid-phase reaction. 相似文献
992.
Bai Y Song N Gao JP Sun X Wang X Yu G Wang ZY 《Journal of the American Chemical Society》2005,127(7):2060-2061
A new, practical approach to a variety of highly electrooptically active polymers for device development is described. It involves the use of a new thermally cross-linkable, hyperbranched oligomer containing nonlinear optical (NLO) chromophores as a macromolecular dopant in a common host polymer. A series of NLO polymeric blends were readily formulated and showed large and stable electrooptic (EO) coefficients (up to 65 pm/V). In comparison with previously studied linear NLO polyimides and guest-host polymers doped with molecular chromophores and even linear NLO analogous oligomers, this new approach offers clear advantages for device development in terms of improved poling efficiency, larger EO coefficients, good temporal stability, and versatile material formulation. 相似文献
993.
994.
合成了2,2-二甲基-N-羟乙基-1,3-噁唑烷(OX),并以其为结构单元合成了2种多官能度的噁唑烷化合物——丙二酸二-2,2-二甲基-N-羟乙基-1,3-噁唑烷酯(OX1)和1,1,5,5-戊烷端四甲酸四-2,2-二甲基-N-羟乙基-1,3-噁唑烷酯(OX2).采用13C核磁共振谱、质谱、元素分析和傅里叶变换红外光谱对产物结构进行表征,并探索了产物用于单组份湿固化聚氨酯(SPU)体系的潜固化剂性能.研究了固化体系的表观性能、力学性能和热性能.结果表明:纯湿固化SPU发泡且膨胀,拉伸强度为3.2 MPa,断裂伸长率为364%;而SPU-OX2固化体系的拉伸强度达27.2 MPa,是纯SPU固化体系拉伸强度(3.2 MPa)的9倍;SPU-OX2固化体系断裂伸长率达457%,是纯SPU固化体系断裂伸长率(364%)的1.26倍.聚氨酯中加入噁唑烷OX1和OX2为潜固化剂,不仅较好改善了聚氨酯的表观性能,而且增加了聚氨酯预聚体的力学性能和热稳定性. 相似文献
995.
Yu-Cai He Lei Gong Feng Liu Ting Lu Qing Qing Li-Qun Wang Yue Zhang Feng-Ting Gao Xi Wang 《Applied biochemistry and biotechnology》2014,173(4):894-903
In the conversion of cassava starch dregs to biogas by anaerobic fermentation, the biogas residue (BR) containing lignocellulosic materials still remained in the environment. In order to effectively utilize BR, the complexed 1-methyl-3-methylimidazolium dimethyl phosphate ([Mmim]DMP) media were used for pretreating cellulosic materials. After the optimization of pretreatment, the IL [Mmim]DMP-HCl-water (78.5:1.5:20, w/w/w) pretreament media were used for pretreating BR at 130 °C for 30 min. Furthermore, BR pretreated could be effectively saccharified by cellulase of Galactomyces sp. CCZU11-1. Moreover, BR could be used as a cheap carbon source for the production of Galactomyces sp. CCZU11-1 cellulase. After the culture optimization, the optimal culture conditions were obtained as follows: BR 5 g/L, (NH4)2SO4 5 g/L, K2HPO4 2 g/L, MgSO4 0.2 g/L, NaCl 1 g/L, PEG6000 4 g/L, pH 5.5, and culture temperature 30 °C. After the fermentation for 6 days, the FPA and CMCase were 26.2 and 52.8 U/mL, respectively. In conclusion, waste BR could be chosen as a promising feedstock for biofuels. 相似文献
996.
Z. H. He G. B. Gao Y. M. Zhang 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(7):1191-1195
In the present work, the decorated purified raw multi-walled carbon nanotubes (R-MWCNTs) were obtained by chemical modification (CM) by treatment with concentrated sulfuric acid and concentrated nitric acid mixture with a certain volume ratio of 1: 3. The R-MWCNTs and CM-MWCNTs samples were investigated by X-ray Diffraction (XRD) analysis and Fourier transform infrared spectroscopy (FT-IR). The prepared MWCNTs were homogeneously dispersed in water using a commercial surfactant (Polyvinyl pyrrolidone, (PVP)) and ultra-sonication. The dispersion of MWCNTs was obtained by UV-Vis analysis. The results show that chemical modification purified MWCNTs and more effective functional groups were attached on the surface of MWCNTs. Meanwhile, R-MWCNTs and CM-MWCNTs were uniformly distributed in aqueous PVP solution and the dispersion of CM-MWCNTs in water was better. 相似文献
997.
Jian Gao You-Yong Xu Hong-Mei Yang Hong Xu Feng Xue Sha Li Xiao-Hai Feng 《Applied biochemistry and biotechnology》2014,173(6):1419-1430
An inulinase-producing strain, Paenibacillus polymyxa ZJ-9, was isolated from natural sources to produce R,R-2,3-butanediol via one-step fermentation of raw inulin extracted from Jerusalem artichoke tubers. The inulinase gene from P. polymyxa ZJ-9 was cloned and overexpressed in Escherichia coli BL21 (DE3), and the purified recombinant inulinase was estimated to be approximately 56 kDa by both sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE) and gel filtration chromatography. This result suggests that the active form of the inulinase is probably a monomer. Terminal hydrolysis fructose units from the inulin indicate that enzymes are exo-inulinase. The purified recombinant enzyme showed maximum activity at 25 °C and pH 6.0, which indicate its extreme suitability for industrial applications. Zn2+, Fe2+, and Mg2+ stimulated the activity of the purified enzyme, whereas Co2+, Cu2+, and Ni2+ inhibited enzyme activity. The K m and V max values for inulin hydrolysis were 1.72 mM and 21.69 μmol min?1 mg?1 protein, respectively. The same parameters toward sucrose were 41.09 mM and 78.7 μmol min?1 mg?1 protein, respectively. Considering its substrate specificity and other enzymatic characteristics, we believe that this inulinase gene from P. polymyxa ZJ-9 could be transformed into other special bacterial strains to allow inulin conversion to other biochemicals and bioenergy through one-step fermentation. 相似文献
998.
Rui Gao Bai-Wang Sun Jun Lin Xiao-Li Gao 《Journal of Thermal Analysis and Calorimetry》2014,117(2):731-739
Studies of active drug-excipient compatibility represent an important phase in the preformulation stage of the development of all dosage forms. For the development of conjugation estrogens and medroxyprogesterone acetate (MPA) double-layer tablets, techniques of thermal, isothermal stress testing (IST), and molecular vibrational spectroscopy analysis were performed to access the compatibility. Differential scanning calorimetry (DSC) studies were used as an important and complementary tool during preformulation to determine drug-excipient compatibility. On the basis of DSC results, MPA was found to be compatible with polyethylene glycol 6000. However, the results of Raman and IST studies showed that all the excipients defined in the prototype formula were found to be compatible with MPA. Overall, the compatibility of selected excipients with MPA was successfully evaluated using a combination of thermal and IST methods, and the formulations developed using the compatible excipients were found to be stable. 相似文献
999.
Dunhua Hong Taisong Pan Dayu Feng Zhenlong Huang Feiyi Liao XiaoMei Li Yin Zhang Min Gao 《Journal of Sol-Gel Science and Technology》2014,71(3):464-469
(LaBa)Co2O5+δ (LBCO) thin films were successfully fabricated on Si (001) substrates by polymer-assisted deposition method. Microstructures were examined by X-ray diffraction technique, which confirmed the films were a single phase, pseudo cubic structure. The electrical transport properties of the films were investigated by the temperature dependence of films resistance, which suggested that LBCO films have typical semiconductor properties. After circle tests, the oxygen–hydrogen response rate did not show obvious variation in the specific temperature environment of 580 °C. This demonstrates that the LBCO thin films have a superior stability in both oxygen and hydrogen (6 % H2, 94 % N2) environment. Simultaneously, the drastic changes of films resistance (from ~106 to ~102 Ω) with the switch of redox (O2–H2) environment within such a short time (~2.2 s) indicated that LBCO films have an excellent oxygen sensitive property and extraordinary fast surface exchange rate. 相似文献
1000.
Shou-Nian Ding Chun-Mei Li Bu-Hong Gao Osman Kargbo Neng Wan Xi Chen Chan Zhou 《Mikrochimica acta》2014,181(15-16):1957-1963
Fluorescent gold nanoclusters (Au-NCs) were synthesized by a one-pot method using 11-mercaptoundecanoic acid as a reducing and capping reagent. It is found that the red fluorescence of the Au-NCs is quenched by the introduction of Eu(III) at pH 7.0, but that fluorescence is restored on addition of phosphate. The Au-NCs were investigated by transmission electron microscopy and fluorescence photographs. The effect of pH on fluorescence was studied in the range from pH 6 to 10 and is found to be strong. Based on these findings, we have developed an assay for phosphate. Ions such as citrate, Fe(CN)6 3?, SO4 2?, S2O8 2?, Cl?, HS?, Br?, AcO?, NO2 ?, SCN?, ClO4 ?, HCO3 ?, NO3 ?, Cd2+, Ba2+, Zn2+, Mg2+, and glutamate do not interfere, but ascorbate and Fe3+ can quench Au-NCs fluorescence. The fluorescent nanocluster probe responds to phosphate in the range from 0.18 to 250 μM, and the detection limit is 180 nM. The probe also responds to pyrophosphate and ATP. Figure
Off/on fluorescence sensor for phosphate based on Eu3+-modulated Au NCs thanks to the competition of oxygen-donor atoms from phosphate with those from the carboxylate groups was developed 相似文献