Cost-effective fabrication of perdurable electrodeposited TiO2 nano-layers on stainless steel electrodes applicable to photocatalytic degradation of methylene blue

Research on Chemical Intermediates - Titanium oxide nano-layers were fabricated by a direct electrodeposition method, including Ti as anode and stainless steel as cathode in a non-aqueous media....     

Simultaneous quantification of ten cytotoxic drugs by a validated LC–ESI–MS/MS method

A liquid chromatography separation with electrospray ionisation and tandem mass spectrometry detection method was developed for the simultaneous quantification of ten commonly handled cytotoxic drugs in a hospital pharmacy. These cytotoxic drugs are cytarabine, gemcitabine, methotrexate, etoposide phosphate, cyclophosphamide, ifosfamide, irinotecan, doxorubicin, epirubicin and vincristine. The chromatographic separation was carried out by RPLC in less than 21 min, applying a gradient elution of water and acetonitrile in the presence of 0.1% formic acid. MS/MS was performed on a triple quadrupole in selected reaction monitoring mode. The analytical method was validated to determine the limit of quantification (LOQ) and quantitative performance: lowest LOQs were between 0.25 and 2 ng mL(-1) for the ten investigated cytotoxic drugs; trueness values (i.e. recovery) were between 85% and 110%, and relative standard deviations for both repeatability and intermediate precision were always inferior to 15%. The multi-compound method was successfully applied for the quality control of pharmaceutical formulations and for analyses of spiked samples on potentially contaminated surfaces.     

Crystal and magnetic structures of the brownmillerite compound Ca2Fe1.039(8)Mn0.962(8)O5

The crystal and magnetic structures of the brownmillerite material, Ca₂Fe_1.039(8)Mn_0.962(8)O₅ were investigated using powder X-ray and neutron diffraction methods, the latter from 3.8 to 700 K. The compound crystallizes in Pnma space group with unit cell parameters of a=5.3055(5) Å, b=15.322(2) Å, c=5.4587(6) Å at 300 K. The neutron diffraction study revealed the occupancies of Fe³⁺ and Mn³⁺ ions in both octahedral and tetrahedral sites and showed some intersite mixing and a small, ∼4%, Fe excess. While bulk magnetization data were inconclusive, variable temperature neutron diffraction measurements showed the magnetic transition temperature to be 407(2) K below which a long range antiferromagnetic ordering of spins occurs with ordering wave vector k=(000). The spins of each ion are coupled antiferromagnetically with the nearest neighbors within the same layer and coupled antiparallel to the closest ions from the neighboring layer. This combination of intra- and inter-layer antiparallel arrangement of spins forms a G-type magnetic structure. The ordered moments on the octahedral and tetrahedral sites at 3.8 K are 3.64(16) and 4.23(16) μ_B, respectively.     

Precise study of the first deflecting magnet of "Rhodotron" (TT200) using transfer matrices and ANSYS11

The beam trajectory in the first deflecting magnet of "Rhodotron" TT200 has been analyzed precisely by both optical and simulation methods.We found discrepancies between these two methods at the order of (10~(-3)) for the slit distance and deflecting radius and at the order of (10~(-4)) for the magnetic flux density.The main goal of the paper is beam focusing, considering the angular and momentum dispersion of the particles for the magnet designed by ANSYS.     

可重复使用的新型催化剂的合成、表征及在绿色条件下催化Suzuki和Heck反应:锚合在磁性纳米多孔的MCM-41上Pd(0)希夫碱络合物

将Pd希夫碱络合物固定在磁性的MCM-41表面上,做为环境友好且可循环使用的新型多相纳米催化剂,并采用红外光谱、振动探针式磁强计、能量散射谱、透射电镜、扫描电镜、热重、电感耦合等离子体发射光谱和X-射线衍射等对其进行了全面的表征.然后将该催化剂用于以PEG为绿色溶剂的一步法Suzuki和Heck合成反应中,均以较高收率得到目标产物.该法主要优点为反应时间短、反应条件绿色友好、操作简便、无需使用有毒的有机溶剂、催化剂使用量低,且底物适用性广.更为重要的是,通过外部磁场即可方便地将催化剂从反应混合物中分离出来,可重复使用数次而活性和稳定性未见明显下降.     

Current trends in direct transformation of waste printed circuit boards (WPCBs) into value-added materials and products

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Electrical conductivity of Sr<Subscript>2-x</Subscript>Ca<Subscript>x</Subscript>FeMnO<Subscript>5</Subscript> (<Emphasis Type="Italic">x</Emphasis> = 0, 1, 2)

Variation of the electrical conductivity due to changes in crystal structure in a series of oxygen-deficient perovskites, Sr_2-xCa_xFeMnO₅ (x?=?0, 1, 2), has been investigated. The correlation between structural order and various aspects of electrical conductivity is demonstrated using X-ray and electron diffraction, transmission and scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and variable-temperature electrical conductivity studies. The increase in structural order from Sr₂FeMnO₅ to CaSrFeMnO₅ and Ca₂FeMnO₅ affects the cation oxidation states. The XPS data indicate that trivalent Mn is stabilized as the structural order increases. The crystallite size is also correlated with structural order, where the increase in structural order leads to a systematic increase in crystallite size. Electrical conductivity studies were performed in both argon and air atmosphere for all three materials in a wide temperature range, from 298 K (25 °C) to 1073 K (800 °C). At room temperature, there is a direct correlation between ordering and electrical conductivity. Variable-temperature conductivity studies lead to a remarkable observation, where the highest conductivity at elevated temperature belongs to the CaSr compound that has an intermediate degree of structural order. This indicates that there is an optimum degree of ordering that can lead to the highest conductivity at high temperature. Comparison between conductivity studies in air and argon atmosphere indicates that the conductivity of the highly ordered Ca₂ compound remains almost unaffected by the change in atmosphere from argon to air. However, the less-ordered CaSr and Sr₂ compounds show an increase in conductivity in air compared to the argon atmosphere. Remarkably, the upturn in the conductivity of the less-ordered materials is interrupted and a decrease is observed at high temperature in air, whereas the ordered Ca₂ compound shows increase in conductivity in the entire temperature range.     

Radar Absorption Properties of Ni0.5Zn0.5Fe2O4/PANI/epoxy Nanocomposites

A nitrate? citrate gel was prepared from metallic nitrates and citric acid by sol? gel process and was further used to synthesize Ni_0.5Zn_0.5Fe₂O₄ nanocrystalline powder by auto‐combustion. Then, two novel 15 and 35% (w/w) magnetic Ni_0.5Zn_0.5Fe₂O₄ containing polyaniline nanocomposites, named as PANI‐Ni15 and PANI‐Ni35, respectively, were prepared via in‐situ polymerization of aniline in an aqueous solution containing proper amount of Ni_0.5Zn_0.5Fe₂O₄ magnetic powder. The incorporation of the nanopowders to PANI matrix was confirmed by X‐ray diffraction (XRD), IR and SEM. Synthesized PANI‐NiZn ferrite composite particles were subsequently added to an epoxy resin matrix to produce related nanocomposites. The morphological properties of these nanocomposite materials were investigated by SEM and TEM. The electromagnetic‐absorbing properties were studied by measuring the reflection loss in the frequency range of 8.0 to 12.0 GHz. Results showed the reflection loss of the PANI‐Ni35 composite is higher than pure polyaniline and PANI‐Ni15. The good reflection loss of the nanocomposites suggests their potential applicability as radar absorber.     

Fabrication of Al/AlN nano‐composite layers by friction stir processing of 6061 Al‐T6 substrate

Friction stir processing was employed for the production of Al/AlN nano‐composite layers on a 6061 Al‐T6 substrate. Nano‐sized AlN powder was inserted in a groove in the middle length of the substrate. Defect‐free layers were achieved using tool rotation and substrate advancing speeds in the range of 900–1400 rpm and 63–310 mm/s, respectively. Subsequent passes were conducted to break‐up AlN clusters that formed in a non‐uniform fashion after initial pass. The grain size of aluminum matrix was found to decrease by the introduction of AlN powder. A nano‐composite layer with near uniform dispersion of nano‐sized AlN reinforcements with a ~9.6% volume fraction was achieved in a matrix of fine dynamically restorated Al grains with a mean size of ~2.5 µm after three subsequent passes. This layer showed an average micro hardness value of ~164 HV (much greater than ~103 HV of the underlying substrate). In addition, the nano‐composite layer exhibited superior dry sliding wear performance against hardened steel compared to that of 6061‐T6 substrate. Increasing tool rotation and substrate advancing speeds were found to decrease the AlN content of the processed layer possibly due to increasing in powder scattering by the pin tool. This was associated with a decrease and increase in hardness values and wear‐loss data, respectively. Copyright © 2014 John Wiley & Sons, Ltd.