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991.
通过水热法制备碳微球、共沉淀法制备空心Zn Fe2O4和原位聚合法制备Zn Fe2O4/Si O2/PANI复合物,并表征其结构、形貌、组成和性质.结果表明,Si O2对铁氧体的包覆能提高二元复合物对染料废水的降解性能;铁氧体与二氧化硅物质的量比(nZn Fe2O4/nSi O2)为1:3的Zn Fe2O4/Si O2复合物对染料废水具有较好的降解作用;Zn Fe2O4/Si O2/PANI复合物对染料废水的光催化降解活性随苯胺质量分数(wAn)的增加而增大,当wAn为50%时,Zn Fe2O4/Si O2/PANI复合物对染料废水去除率高达98%.样品因具有磁性而回收方便,重复使用性能良好. 相似文献
992.
At increasing external load, numerous microcracks propagate in discrete and successive stages within a body of concrete material according to the hierarchy of their tensile fracture strengths. Each microcrack propagation is conditional upon the statistical encounter of its associated fracture criterion. This paper shows the development of a statistical model for the progressive microcrack growth process within a body of concrete material at monotonic uniaxial loading in compression to ultimate failure. This model is formulated by using the Weibull's statistical theory of the strength of materials. The body of heterogeneous concrete material is simulated as a continuum comprising a large population of microscopic “weakest-link” isoenergy elements, each of which contains a unit-volume of representative micro-structural material which is linearly elastic, homogeneous and isotropic. The statistical modelling is derived from the stochastic evaluation of the tensile micro-fracture probabilities of these isoenergy elements at increasing global uniaxial compressive strains. 相似文献
993.
994.
Kong J Sun W Wu X Deng J Lu Z Lvov Y Desamero RZ Frank HA Rusling JF 《Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)》1999,48(1):101-107
Direct reversible electron transfer for photosynthetic reaction center from wild type Rhodobacter sphaeroides re-constituted in polycation sandwiched monolayer film was observed in this work. The redox potential E0' = 0.46 V vs. NHE for first primary donor redox couple P/P+ was accurately measured from reversible CV or SWV peaks, which were quite close to those obtained from optic redox titration method. Reaction center (RC) in film was found re-constituted in such an ordered way that the orientation of RC favored the electron transfer in film. Thus, the protein electroactivity seems to be turned on in this artificial biomimic thin film. Furthermore, RC in the film features a photo-induced redox-peak fluctuation, suggesting an intact and functional state for RC in such film. Redox peaks were also found dependent of pH, implying a proton-coupled electron transfer occurring in film. Charge recombination was observed accompanied with change of electrochemical driving force. Electrochemical model assuming several classes of electroactive sites in the films on the electrode with a dispersion of standard potentials successfully fits SWV experimental data at different pulse height and frequency. 相似文献
995.
SnO2 films have been deposited on Y-stabilized ZrO2 (YSZ) (1 0 0) substrates at different substrate temperatures (500–800 °C) by metalorganic chemical vapor deposition (MOCVD). Structural, electrical and optical properties of the films have been investigated. The films deposited at 500 and 600 °C are epitaxial SnO2 films with orthorhombic columbite structure, and the HRTEM analysis shows a clear epitaxial relationship of columbite SnO2(1 0 0)||YSZ(1 0 0). The films deposited at 700 and 800 °C have mixed-phase structures of rutile and columbite SnO2. The carrier concentration of the films is in the range from 1.15×1019 to 2.68×1019 cm−3, and the resistivity is from 2.48×10−2 to 1.16×10−2 Ω cm. The absolute average transmittance of the films in the visible range exceeds 90%. The band gap of the obtained SnO2 films is about 3.75–3.87 eV. 相似文献
996.
Junping Gu Xiandong Zeng Bo Kong Youan Mao Wei Liu Wanzhi Wei 《Chromatographia》2010,71(9-10):769-774
A rapid, simple and reliable analytical procedure has been developed for the determination of polyphenols, including chlorogenic acid, rutin and scopoletin, in tobacco samples. After extraction, the polyphenols were analyzed by micellar liquid chromatography coupled with UV detection at 340 nm without sample preparation step. The compositions of the micellar mobile phase for the separation of these polyphenols were selected adequately by a chemometric method. The optimal resolution and satisfactory peak shapes were achieved with 0.022 mol L?1 sodium dodecyl sulfate and 0.45% (volume fraction) 1-propanol solution at pH 5.0 using Eclipse XDB-C18 (250 mm × 3.0 mm, 5 μm) column. The limits of detection for chlorogenic acid, rutin and scopoletin were 0.15, 0.29 and 0.22 μg mL?1, respectively. This validated method was successfully applied to qualitatively and quantitatively analyze the polyphenols in tobacco in less than 10 min. 相似文献
997.
Four divalent metal thiocyanate coordination compounds containing a rigid functional pyridine ligand
Lin Kong Wei-Jie Li Xian-Lei Li Wen-Qian Geng Fu-Ying Hao Jie-Ying Wu Hong-Ping Zhou Jia-Xiang Yang Yu-Peng Tian Bao-Kang Jin 《Polyhedron》2010
A series of new coordination compounds Zn(SCN)2L2 (1), Co(SCN)2L2 (2), [Cd(SCN)2L2·2L]n (3) and [CdHg(SCN)4L2]n (4) have been prepared by self-assembly of a rigid functional pyridine ligand, trans-4-[4′-(N-methyl-N-hydroxyethyl)amimo]styryl pyridine (abbreviated as L) with M(SCN)x (M: Zn, Co, Cd, CdHg; x: 2, 4). The crystal structures indicate that 1 and 2 are mononuclear compounds while 3 and 4 are coordination polymers. O–H?N, C–H?O, O–H?π and C–H?π hydrogen bonds play significant roles in the final crystal structures. The solid-state luminescence properties have been measured. The results indicate that the photoluminescence spectra of all the compounds can be changed by the frameworks and introducing of different metal ions. 相似文献
998.
Chang Yi Kong Yuan Yuan Gu Masato Nakamura Toshitaka Funazukuri Seiichiro Kagei 《Fluid Phase Equilibria》2010
Binary diffusion coefficients, D12, of the metal acetylacetonates, palladium(II) acetylacetonate and cobalt(III) acetylacetonate, were measured from 308.2 to 343.2 K over the pressure range from 9 to 40 MPa at infinite dilution in supercritical carbon dioxide using the chromatographic impulse response method. The effects of pressure, temperature, density, and viscosity on D12 values were examined. It was observed that the D12 values of palladium(II) acetylacetonate and cobalt(III) acetylacetonate were larger than those of lipids with similar molecular weights, such as arachidonic acid and monoolein, respectively. Furthermore, the measured D12 data of each metal acetylacetonate were well correlated by the hydrodynamic equation D12/T as a function of carbon dioxide viscosity. 相似文献
999.
对于底物不溶于水的纤维素降解反应而言,为了增强纤维素酶的活性,在丁二酸二异辛酯磺酸钠(AOT)/异辛烷反胶束体系中加入非离子表面活性剂TritonX-100进行纤维素降解实验.结果表明,在AOT中加入非离子表面活性剂TritonX-100可以使纤维素酶的活性提高,非离子表面活性剂TritonX-100与AOT的最佳物质的量之比是0.20.考察了水与表面活性剂的物质的量之比(Wo)、不同酸度(pH)和不同温度(T)等其他反应条件对纤维素降解反应的影响.研究结果表明,反应的最佳条件是:Wo为3.3,T为315.11K,pH为5.10. 相似文献
1000.
选择邻苯二甲酸和氢氧化钠作为反应物,利用液相合成方法合成了水合邻苯二甲酸钠.利用X射线粉末衍射、化学与元素分析等方法表征了它的组成和结构.利用精密自动绝热热量计测定了该化合物在78~366K温区的摩尔热容.将该温区的摩尔热容实验值用最小二乘法拟合得到摩尔热容(Cp,m)对温度(T)的多项式方程,用此方程进行数值积分得到此温度区间内每隔5K的舒平热容值和相对于298.15K时的热力学函数值.另外,依据Hess定律,通过设计合理的热化学循环,利用等温环境溶解-反应热量计分别测量了固相量热反应的反应物和产物在所选溶剂中的溶解焓,从而确定反应的反应焓为:ΔrHm=29.073±1.05kJ·mol-1.最后,利用反应的反应焓和其它反应物和产物已知的热力学数据计算出水合邻苯二甲酸钠的标准摩尔生成焓为:-1493.637±1.11kJ·mol-1. 相似文献