Formation and structure of composite coating of HDA and micro-plasma oxidation on A3 steel

Composite coatings were obtained on A3 steel by hot dipping aluminum(HDA) at 720 ℃ for 6 min and micro-plasma oxidation(MPO) in alkali electrolyte. The surface morphology, element distribution and interface structure of composite coatings were studied by means of XRD, SEM and EDS. The results show that the composite coatings obtained through HDA/MPO on A3 steel consist of four layers. From the surface to the substrate, the layer is loose Al2O3 ceramic, compact Al2O3 ceramic, Al and FeAl intermetallic compound layer in turn. The adhesions among all the layers are strengthened because the ceramic layer formed at the Al surface originally, FeAl intermetallic compound layer and substrate are combined in metallurgical form through mutual diffusion during HDA process.Initial experiment results disclose that the anti-corrosion performance and wear resistance of composite coating are obviously improved through HDA/MPO treatment.

Antioxidative and hepatoprotective activities of a novel polysaccharide (LSAP) from Lepista sordida mycelia

A novel alkali-soluble polysaccharide from Lepista sordida(LSAP)mycelia with antioxidative and hepatoprotective activities was characterized.The weight-average molecular weight and number-average molecular weight of LSAP were 1.442×10^(3) and 6.05×10^(2) kDa,respectively.LSAP was consisted of glucose(57.9%),xylose(31.8%),and small amounts of rhamnose,arabinose,galactose,glucuronic acid,and galacturonic acid(1.2%–3.1%).The FT-IR and 2D NMR confi rmed that LSAP was composed of Xylp,Araf,4-O-Me-α-D-GlcpA,(1→4)-linkedβ-D-Glcp,and(1→4)-α-D-GalA,andβ-glycosidic linkages between these sugar units.LSAP displayed notable effects on 1,1-dephenyl-2-picryhydrazyl(DPPH)radical scavenging,hydrogen peroxide scavenging,lipid peroxidation inhibitory ability,reducing power and Fe^(2+)chelating property.These biological effects were further verifi ed by suppressing CCl_(4)-induced oxidative liver damage in mice at doses of 100 and 200 mg/kg.Administration of LSAP in mice prior to CCl_(4) signifi cantly prevented the CCl_(4)-induced elevation in serum alanine aminotransferase,aspartate aminotransferase,and hepatic malondialdehyde.Mice treated with LSAP demonstrated to increase activities in superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)in the liver.We also found out that LSAP prevented CCl_(4)-induced oxidative liver histological alteration.LSAP may exert hepatoprotective effects against CCl_(4)-induced damage through antioxidant mechanisms in model mice.

Influence of La-dopant on the Material Characteristics and Supercapacitive Performance of MnO_2 Electrodes

Manganese dioxide was synthesized by electrodeposition method with Mn （CH3COO）24H2O as a raw material. La（NO3）3？6H2O was doped in electroyte during the preparing process to improve the performance of MnO2 electrodes. The micrographs, crystal structure and element content of electrodes were analyzed by SEM, XRD and atomic absorption spectroscopy, respectively. It is found that the La content ratio in the dioxide can be easily controlled by adjusting the composition of the plating solution. Appropriate amount of doped La can increase the surface area of Mn/La materials, resulting in the supercapacitive behavior enhancement. Electrochemical tests show that the specific capacitance is significantely increased from 198.72 F？g-1 to 276.60 F？g-1 by La-doping.

Improvement of β-phase crystal formation in a BaTiO3-modified PVDF membrane

In this paper,low temperature plasma is used to modify the surface of barium titanate（BaTiO3）nanoparticles in order to enhance the interfacial compatibility between ferroelectric poly（vinylidene fluoride）（PVDF） and BaTiO3 nanoparticles.The results demonstrate that oxygenic groups are successfully attached to the BaTiO3 surface,and the quantity of the functional groups increases with the treatment voltage.Furthermore,the effect of modified BaTiO3 nanoparticles on the morphology and crystal structure of the PVDF/BaTiO3 membrane is investigated.The results reveal that the dispersion of BaTiO3 nanoparticles in the PVDF matrix was greatly improved due to the modification of the BaTiO3 nanoparticles by air plasma.It is worth noting that the formation of a β-phase in a PVDF/modified BaTiO3 membrane is observably promoted,which results from the strong interaction between PVDF chains and oxygenic groups fixed on the BaTiO3 surface and the better dispersion of BaTiO3 nanoparticles in the PVDF matrix.Besides,the PVDF/modified BaTiO3 membrane at the treatment voltage of 24 k V exhibits a lower water contact angle（≈68.4°） compared with the unmodified one（≈86.7°）.Meanwhile,the dielectric constant of PVDF/BaTiO3 nanocomposites increases with the increase of working voltage.

Ruthenium(Ⅱ) Complexes Bearing Schiff Base Ligands for Efficient Acceptorless Dehydrogenation of Secondary Alcohols

Four ruthenium(Ⅱ)complexes 1-4[RN=CH-(2,4-(Bu)_(2)C_(6)H_(2)O)]RuH(PPh_(3))_(2)(CO)(R=C_(6)H_(5),1;R=4-MeC_(6)H_(4),2;R=4-CIC_(6)H_(4),3;R=4-BrC_(6)H_(4),4)bearing Schiff base ligands were prepared by treating RuHCICO(PPh_(3))_(3) with RN=CH-(2,4-(Bu)_(2)C_(6)H_(2)OH(L1-L4)in the presence of triethylamine.Their structures were fully characterized by elemental analysis,IR,NMR spectroscopy and X-ray crystal-lography.

Meticulous guard: The role of Al/F doping in improving the electrochemical performance of high-voltage spinel cathode

Spinel LiNi0.5Mn1.5O4,which is considered as one of the most attractive candidates for high energy density battery due to its high voltage platform over 4.7 V,suffers from the side reactions with electrolyte,strong oxidability of Ni4þand therefore the complicated and frangible Solid Electrolyte Interfaces(SEI)layer that hinders the practical application of LiNi0.5Mn1.5O4.In this work,traditional coprecipitation method is applied and improved by anion and cation doping method to construct superior interface on the surface of LiNi0.5Mn1.5O4 to suppress side reactions especially at high temperature.Detailed properties including structure,morphology and electrochemical performance of pristine sample,single-doped and co-doped samples are probed.Physical characterizations reveal that the co-doped sample with regular octahedron has a moderate grain size and specific surface area between Al and F single doping,and holds the advantages of rate performance and capacity retention causing by Al doping and better stability under high temperature constructing by F.It exhibits the best capacity retention of 92%after 200 cycles under 55 C,which is higher than that of the pristine sample(87%).Analysis of the electrode after cycling shows that doping reduces the thickness of the electrode interface film and the content of inorganic substances such as LiF to improve the interface characteristics and the high temperature cycling performance.This work has certain significance for the commercial application of LiNi0.5Mn1.5O4.

Corrosion Resistance of Sintered NdFeB Permanent Magnet With Ni-P/TiO_2 Composite Film

The Ni-P/TiO2 composite film on sintered NdFeB permanent magnet was investigated by X-ray diffraction （XRD）,environmental scanning electron microscopy （ESEM）,and energy dispersive X-ray spectrometer （EDX）. The corrosion resistance of Ni-P/TiO2 film coated on NdFeB magnet,in 0.5 mol/L NaCl solution,was studied by potentiodynamic polarization,salt spray test and electrochemical impedance spectroscopy （EIS） techniques. The self-corrosion current density （icorr） and the polarization resistance （Rp） of Ni-P/TiO2 film are 0.22 μA/cm2 （about 14% of that of Ni-P coating）,and 120 kΩ·cm2 （about 2 times of that of Ni-P coating）,respectively. The anti-salt spray time of Ni-P/TiO2 film is about 2.5 times of that of the Ni-P coating. The results indicate that Ni-P/TiO2 film has a better corrosion resistance than Ni-P coating,and the composite film increases the corrosion resistance of NdFeB magnet markedly.