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Matthias Tacke Lorcan T. Allen William M. Gallagher Oscar Mendoza Franz-Josef K. Rehmann 《Journal of organometallic chemistry》2004,689(13):2242-2249
Starting from 6-(p−N,N-dimethylanilinyl)fulvene (1a) or 6-(pentamethylphenyl)fulvene (1b) [1,2-di(cyclopentadienyl)-1,2-di(p−N,N-dimethylaminophenyl)ethanediyl] titanium dichloride (2a) and [1,2-di(cyclopentadienyl)-1,2-bis(pentamethylphenyl)ethanediyl] titanium dichloride (2b) and their corresponding dithiocyanato complexes (3a, 3b) were synthesized. Titanocene 2b did not show a cytotoxic effect, but when 2a was tested against pig kidney carcinoma cells (LLC-PK) or human ovarian carcinoma cells (A2780/cp70) inhibitory concentrations (IC50) of 2.7 × 10−4 and 1.9 × 10−4 M, respectively, were observed. 相似文献
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The kinetics of phase transitions of milk fat triacylglycerols, as model multicomponent lipid systems, were studied under
shear in a Couette cell at 17 °C, 17.5 °C and 20 °C under shear rates ranging from 0 to 2880s^-1 using synchrotron X-ray diffraction.
Two-dimensional diffraction patterns were captured during the crystallization process. No effect of shear on onset time for
phase α from the liquid was observed. Afterwards a two-regime crystallization process was observed. During the first regime,
as observed in other systems, shear reduced the onset time of the phase transition from phase α to 2880s−. The model previously developed for palm oil (ODE model) worked well to describe this regime, confirming the general value
of the proposed ODE model. However, the ODE model did not satisfactorily describe the second regime. We found that, as the
system gets closer to equilibrium, the growth regime becomes controlled by diffusion, manifested by the kinetics following
a dependence. This regime was found to be consistent with a mechanism combining step growth at a kink with progressive selection
of the crystallizing moieties. This mechanism is in agreement with the displacement of the diffraction peak positions, which
revealed how increased shear rate promotes the crystallization of the higher melting fraction affecting the composition of
the crystallites. 相似文献
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J.H. He S.L. YuanZ.M. Tian Y.S. YinP. Li Y.Q. WangK.L. Liu S.J. YuanX.L. Wang L. Liu 《Journal of magnetism and magnetic materials》2008
The magnetic properties of 1.5 at% Fe-doped NiO bulk samples were investigated. The samples were prepared by sintering the corresponding precursor in air at temperatures between 400 and 800 °C for 6 h. The synthesis was by a chemical co-precipitation and post-thermal decomposition method. In order to allow a comparison, a NiO/0.76 at% NiFe2O4 mixture was also prepared. The X-ray diffraction pattern shows that the samples that were sintered at 400 and 600 °C remain single phase. As the sintering temperature increased to 800 °C, however, the sample becomes a mixture of NiO and NiFe2O4 ferrite phases. The samples were investigated by measuring their magnetization as a function of magnetic field. The samples sintered between 400 and 800 °C and the one mixed directly with NiFe2O4 nanoparticles show a coercivity value of Hc≈200, 325, 350 and 110 Oe, respectively. The magnetic properties of the samples depend strongly on the sintering temperature. Simultaneously, the field-cooling hysteresis loop shift also observed after cooling the sample sintered at 600 °C to low temperature suggests the possibility of the existence of a ferromagnetic/antiferromagnetic exchange coupling. 相似文献
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Govindasamy Chandrasekar 《Journal of Non》2008,354(33):4027-4030
A supernatant solution of silicate species extracted from coal fly ash in a power plant by alkali fusion was used under acidic conditions to prepare a mesoporous silica, SBA-16. SBA-16 was used as a template for the synthesis of a mesoporous carbon using sucrose as a carbon source. These mesoporous silica and carbon materials were characterized by XRD, N2 adsorption-desorption, SEM, and TEM. Textural properties of the silica and carbon samples prepared using fly ash were found to be comparable to those prepared by pure chemicals, successfully demonstrating the feasibility of recycling fly ash for the synthesis of high quality porous materials. 相似文献
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Dong Cherng Wen 《Applied Surface Science》2009,256(3):797-804
Plasma-nitriding is used to improve the wear resistance and corrosion resistance of plastic mold steels by modifying the surface layers of these steels. In this study, a precipitation hardenable plastic mold steel (NAK80) was plasma-nitrided at 470, 500, and 530 °C for 4, 8, and 12 h under 25% N2 + 75% H2 atmosphere in an industrial nitriding facility. The microstructures of the base material and nitrided layers as well as the core hardness were examined, and various phases present were determined by X-ray diffraction. The corrosion behaviors were evaluated using anodic polarization tests and salt fog spray tests in 3.5% NaCl solution.The results had shown that plasma-nitriding does not cause the core to soften by overaging. Nitriding and aging could be achieved simultaneously in the same treatment cycle. Plasma-nitriding of NAK80 mold steel produced a nitrided layer composed of an outer compound layer constituting a mixture of ?-nitride and γ′-nitride and an adjacent nitrogen diffusion layer on the steel surface. The amount of ?-nitride and total nitrides increased with an increase in nitriding temperature and nitriding time. Corrosion study revealed that plasma-nitriding significantly improved the corrosion resistance in terms of corrosion potential, corrosion and pitting current density, and corrosion rate. This improvement was found to be directly related to the increase in the amount of ?-nitride at the surface, indicating the amount of ?-nitride controlling the corrosion resistance. 相似文献
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Imran Khan 《Physica B: Condensed Matter》2009,404(16):2395-2400
The effects of tellurium (Te) additives on electrical conductivity, dielectric constant and structural properties of sintered silicon nitride ceramics have been studied. Different amounts of Te (10% and 20%) were added as sintering additives to silicon nitride ceramic powders and sintering was performed. Microstructure and composition were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrical conductivity and dielectric constant (ε′) increase exponentially with temperature greater than 800 K. The electrical conductivity and dielectric constant increase but activation energy decreases from 0.72 to 0.33 eV with the increase of Te concentration. However, the conductivity increases five orders of magnitude at the concentration of 10% of Te in Si3N4. As the Te concentration increases the sintered silicon nitride ceramics become denser. These types of samples can be used as high temperature semiconducting materials. 相似文献
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Effects of processing on the electrical and structural properties of spray deposited CdS:In thin films 总被引:1,自引:0,他引:1
Polycrystalline CdS:In thin films were prepared by the Spray pyrolysis technique (SP) at a substrate temperature Ts=490 °C. The effects of annealing in nitrogen atmosphere at 400 °C and HCl-etching on the electrical and structural properties of the films were investigated. The electrical properties were studied through the analysis of the I-V curves, while the structural properties were studied through the analysis of the X-ray diffraction (XRD) patterns and the scanning electron microscope (SEM) images. An increase in the films’ resistivity was occurred after annealing and/or HCl-etching, which was accompanied by changes in the XRD patterns and SEM images. These changes were related to a phase change from the mixed (cubic and hexagonal) phase to the hexagonal phase which was expected to occur during the aforementioned processes. The X-ray diffraction (XRD) patterns and the scanning electron microscope images confirm this expectation. 相似文献
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The effect of the addition of potassium thiocyanate on potassium dihydrogen phosphate (KDP) crystals, grown from aqueous solution by the temperature lowering method using a microcontroller based seed rotation technique has been studied. As part of nucleation studies, metastable zone width, induction period and crystal growth rate of additive added KDP are determined and analyzed with the pure system. Dielectric measurements were carried out on pure and doped crystals at various temperatures ranging from 313 to 423 K and compared. The crystalline perfection of the grown crystal was studied by the high resolution X-ray diffraction analysis. The crystal grown from additive added solution was subjected to structural, optical transmission, second harmonic generation and hardness studies and the effect of additive on pure system is investigated. 相似文献