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201.
Zhu X Tang X Shi D Jian H Lei H Yeoh WK Zhao B Yang J Li Q Zheng R Dou S Sun Y 《Dalton transactions (Cambridge, England : 2003)》2011,40(37):9544-9550
Bi(2)Sr(3)Co(2)O(y) thin films are prepared on SrTiO(3) (100), (110) and (111) single crystal substrates using the sol-gel method. All the thin films are c-axis oriented regardless of the orientation of the substrate suggesting self-assembled c-axis orientation, and X-ray photoelectron spectroscopy results give evidence of coexistence of Co(3+) and Co(2+) ions in the derived films. Transmission electronic microscopy observations reveal that all samples are c-axis oriented with no obvious differences for different samples, and the c-axis lattice constant is determined as ~15 ? suggesting the misfit structure. A phenomenological thermodynamic phase diagram for self-assembled c-axis orientation is established for misfit cobaltate-based films using chemical solution deposition. All samples behave like semiconductors due to the coexistence of Co(3+)/Co(2+) ions, and the resistivity at 350 K is ~47, 39 and 17 mΩ cm for the thin films on SrTiO(3) (100), (110) and (111), respectively, whereas the Seebeck coefficient at 300 K is 97, 89 and 77 μV K(-1). The successful attainment of Bi(2)Sr(3)Co(2)O(y) thin films with self-assembled c-axis orientation will provide an effective prototype for investigation of growth mechanisms in complex oxide thin films with a misfit structure. 相似文献
202.
In this paper, ammine lithium borohydride (LiBH(4)·NH(3)) was successfully impregnated into multi-walled carbon nanotubes (CNTs) through a melting technique. X-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller, and density measurements were employed to confirm the formation of the nanostructured LiBH(4)·NH(3)/CNTs composites. As a consequence, it was found that the dehydrogenation of the loaded LiBH(4)·NH(3) was remarkably enhanced, showing an onset dehydrogenation at temperatures below 100 °C, together with a prominent desorption of pure hydrogen at around 280 °C, with a capacity as high as 6.7 wt.%, while only a trace of H(2) liberation was present for the pristine LiBH(4)·NH(3) in the same temperature range. Structural examination indicated that the significant modification of the thermal decomposition route of LiBH(4)·NH(3) achieved in the present study is due to the CNT-assisted formation of B-N-based hydride composite, starting at a temperature below 100 °C. It is demonstrated that the formation of this B-N-based hydride covalently stabilized the [NH] groups that were weakly coordinated on Li cations in the pristine LiBH(4)·NH(3)via strong B-N bonds, and furthermore, accounted for the substantial hydrogen desorption at higher temperatures. 相似文献
203.
Corn stover silage is an attractive raw material for the production of biofuels and chemicals due to its high content of carbohydrates
and easy degradability. The effects of Fe(NO3)3 pretreatment conditions on sugar yields were investigated for corn stover silage. In addition, a combined severity factor
was used to evaluate the effect of pretreatment conditions on the concentration of total sugars and inhibitors. Optimum pretreatment
condition was obtained at 150 °C for 10 min with 0.05 M Fe(NO3)3, at which the yields of soluble xylose and glucose in liquid achieved 91.80% of initial xylose, 96.74% of initial arabinose
and 19.09% of initial glucose, respectively, meanwhile, 91.84% of initial xylose, 98.24% of initial arabinose, and 19.91%
of initial glucose were removed. In addition, a severity analysis showed that the maximum sugar concentration of 33.48 g/l
was achieved at combined severity parameter value of 0.62, while the inhibitor concentration was only 0.03 g/l. Fe(NO3)3 is an effective catalyst to enhance hemicellulose hydrolysis in corn stover silage, the yields of monomeric xylose in the
liquid fraction reached as high as 91.06% of initial xylose and 96.22% of initial arabinose, respectively. 相似文献
204.
Tetragonal ZrW1.80V0.20O6.90(OH)2.00(H2O)2.00 hydrate was prepared using an acidic steam hydrothermal (ASH) method. Thermal dehydration followed by phase transformation of this precursor leads to successful synthesis of a novel W-site low-valent substituted cubic ZrW1.80V0.20O7.90 solid solution, the mechanism of this process is studied in detail revealing the hydrate and a metastable orthorhombic phase of V′Wsubstitution solid solution as important intermediate product. This material is found to possess thermal contraction and order-disorder phase transformation properties similar to that of the cubic ZrW2O8. 相似文献
205.
Reactions of lanthanide(III) perchlorate (Ln = Dy, Tb, and Gd), nickel(II) acetate, and ditopic ligand 2-(benzothiazol-2-ylhydrazonomethyl)-6-methoxyphenol (H(2)L) in a mixture of methanol and acetone in the presence of NaOH resulted in the successful assembly of novel Ln(2)Ni(2) heterometallic clusters representing a new heterometallic 3d-4f motif. Single-crystal X-ray diffraction reveals that all compounds are isostructural, with the central core composed of distorted [Ln(2)Ni(2)O(4)] cubanes of the general formula [Ln(2)Ni(2)(μ(3)-OH)(2)(OH)(OAc)(4)(HL)(2)(MeOH)(3)](ClO(4))·3MeOH [Ln = Dy (1), Tb (2), and Gd (3)]. The magnetic properties of all compounds have been investigated. Magnetic analysis on compound 3 indicates ferromagnetic Gd···Ni exchange interactions competing with antiferromagnetic Ni···Ni interactions. Compound 1 displays slow relaxation of magnetization, which is largely attributed to the presence of the anisotropic Dy(III) ions, and thus represents a new discrete [Dy(2)Ni(2)] heterometallic cubane exhibiting probable single-molecule magnetic behavior. 相似文献
206.
207.
Xuebin Ma Fumin Guo Zhen Li Min Wang Wu Zhou 《Journal of Dispersion Science and Technology》2013,34(11):1540-1547
The phase behavior and rheological properties of the concentrated lecithin aqueous solutions were investigated at 37°C. When adding Isopropyl myristate (IPM) to lecithin solutions, besides an anisotropic liquid crystal (LC) phase, an isotropic liquid (L2) region and an isotropic viscous (I) phase are found. By continuously adding Brij 97, the LC region shifts towards higher water content and the L2 region is extended to the area of lower IPM concentration, meanwhile the I phase disappears. By analyzing the shear rate (ηγ=0.1) and yield stress (σ0), adding IPM to lecithin solutions increases the values of ηγ=0.1 and σ0, and after further adding Brij 97, the ηγ=0.1 and σ0 decrease dramatically. Notably, different from the lecithin/DDAB/water system studied by Youssry and Montalvo, in lecithin/Brij 97/IPM/H2O system, at the relatively higher water content area of the LC phase, the water content has little effect on the critical stress. It is also found that the change of dynamic storage modulus (G′) is similar with that of ηγ=0.1 and σ0 parameters when adding IPM and Brij 97. Maxwell model fitting results show that in the LC phase, the relaxation of the water molecule is prolonged by adding IPM and Brij 97 to lecithin solutions. 相似文献
208.
Shuye Yang Xuebin Wang Haixun Guo Jian Liu Fenglong Wang Xianzhong Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):165-171
Mixed ligand fac-tricarbonyl complex of [99mTc(CO)3-DMSA-MIBI] has been prepared starting from the precursor [99mTc(OH2)3(CO)3]+. The complex can be obtained in good yield and purity in a two-step procedure by first attaching meso-2,3-dimercaptosuccinic acid (DMSA, HOOCCH(SH)CH(SH)COOH) with [99mTc(OH2)3(CO)3]+, followed by addition of MIBI [tetrakis-2-methoxyisobutylisonitrile (CH3OC(CH3)2CH2-N≡C) copper(I) tetrafluoroborate] solution. The complex was characterized by TLC and HPLC and was studied by means of octanol-water
partition coefficient, electrophoresis, stability in vitro, and normal mice experiment. Biodistribution in mice demonstrated
that the complex showed higher myocardial uptake after 0.5-hour p.i. The ratios of heart/liver (%ID/g) in the case of 99mTc(CO)3-DMSA-MIBI was higher (1.88) than that observed in case of 99mTc-MIBI1 (0.93) after 0.5-hour p.i. (P<0.05). Results showed that the complex may be developed to a novel myocardial perfusion-imaging agent. 相似文献
209.
Yttria promoted metallic nickel catalysts for the partial oxidation of methane to synthesis gas
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A metallic Ni catalyst was prepared with nickel sponge, followed by acid treatment. It was further promoted with yttria by an impregnation method. The catalysts were characterized by SEM, BET, XRD, TPR, XPS, etc., and studied in the partial oxidation of methane to syngas. The characterization results showed that the yttria promoted metallic Ni catalysts had high specific surface area and more NiO. The reaction results showed that the yttria promoter increased the CH4 conversion and the selectivity for H2 and CO. 相似文献
210.
With new photocatalysts of gold nanoparticles supported on zeolite supports (Au/zeolite), oxidation of benzyl alcohol and its derivatives into the corresponding aldehydes can proceed well with a high selectivity (99?%) under visible-light irradiation at ambient temperature. Au/zeolite photocatalysts were characterised by UV/Vis, X-ray photoelectron spectroscopy (XPS), TEM, XRD, energy-dispersive spectroscopy (EDS), Brauner-Emmet-Teller (BET) analyses, IR and Raman techniques. The surface plasmon resonance (SPR) effect of gold nanoparticles, the adsorption capability of zeolite supports and the molecular polarities of aromatic alcohols were demonstrated to have an essential correlation with the photocatalytic performances. In addition, the effects of light intensity, wavelength range and the role of molecular oxygen were investigated in detail. The kinetic study indicated that the visible-light irradiation required much less apparent activation energy for photooxidation compared with thermal reaction. Based on the characterisation data and the photocatalytic performances, we proposed a possible photooxidation mechanism. 相似文献