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A combined chemical vapor deposition with high-pressure annealing has been developed for the production of phosphorus-doped helical carbon nanofibers (P-HCNFs). The resulting P-HCNFs have a large specific surface area, well-defined three-dimensional hierarchical helical structure and rapid apparent heterogeneous electron transfer. Based on the high electrocatalytic activity, the P-HCNFs were used to develop an amperometric sensor for carbendazim detection. The experimental results demonstrated that the sensor is promising for the determination of carbendazim in food samples due to the high sensitivity, wide linear range and low detection limit. [ABSTRACT FROM AUTHOR]

In this study, a novel Pd/Mn 3 O 4 /plait-like carbon nanocoils (Pd/Mn 3 O 4 /CNCs) catalyst is synthesized by a combined chemical vapor deposition and chemical reduction method. The pretreated Mn 3 O 4 nanoparticles are applied as support materials between Pd nanoparticles and CNCs template. The functional CNCs are covered by Mn 3 O 4 nanomaterials, and the metallic Pd nanoparticles are homogeneously deposited onto the Mn 3 O 4 with smaller sizes compared with those of Pd/CNCs and Pd/VX-72. The as-fabricated electrode of Pd/Mn 3 O 4 /CNCs exhibits higher catalytic activity toward the electro-oxidation of ethanol in alkaline media, more excellent poisoning tolerance, and higher stability than other electrodes. This improved performance of the as-prepared electrocatalyst originates from not only the synergetic effects between the Pd nanoparticles and Mn 3 O 4 , but also the intrinsic characteristic of CNCs. [ABSTRACT FROM AUTHOR]

Abstract: Poly(diallyldimethylammonium chloride) functionalized helical carbon nanotubes (PDDA-HCNTs) were successfully synthesized. The resulting PDDA-HCNTs composite has good conductivity, solubility and ferromagnetic property. The fabricated HCNTs could be conveniently separated and magnetically attached to the magnetic electrode owing to their excellent magnetic properties. An amperometric biosensor was firstly developed based on glucose oxidase (GOD) functionalized PDDA-HCNTs loaded on magnetic glass carbon electrode. The constructed biosensor exhibited excellent electrocatalytic activity and stability for the detection of glucose with a linear range from 5 to 85μM and a low detection limit of 0.72μM at 3σ. The present work offers a new avenue to broaden the applications of HCNTs in electrochemical biosensors. [Copyright &y& Elsevier]

Abstract: The gold nanoparticles/colloidal carbon sphere hybrid material was used for the immobilization of protein, and was developed in biosensing. The hybrid material was fabricated by the assembly of gold nanoparticles onto the surface of colloidal carbon spheres, which constructed a 3D antibody immobilization matrix on the glass carbon electrode and made the immobilized biomolecules hold high stability and bioactivity. After the sandwich-type immunoreaction, the formed HRP-labeled immunoconjugate showed good enzymatic activity for the oxidation of o-phenylenediamine by H2O2. The approach provided a linear response range between 5 and 250ng/mL with a detection limit of 1.8ng/mL. The immunosensor showed good precision, acceptable stability and reproducibility and could be used for the detection of human IgG in real samples, which provided a potential alternative tool for the detection of protein in clinical laboratory. [ABSTRACT FROM AUTHOR]

Recently, a new type of exchange bias (EB) after zero-field cooling has attracted considerable interest mainly in bulk magnetic competing systems. Here, we use a detailed magnetotransport investigation to probe the ground state and zero-field cooled EB (ZEB) in Mn 50 Ni 41 Sn 9 ribbon. Both ZEB and field cooled EB were detected in magnetoresistance results consistent with magnetic measurement. A pure spin-glass ground state is proposed based on parabolic shape of low-field magnetoresistance combined with AC magnetization, memory effect. The appearance of ZEB is attributed to the field-induced nucleation and growth of ferromagnetic domains in the spin glass matrix forming unidirectional anisotropy at the interface. [ABSTRACT FROM AUTHOR]

Abstract: Series of Dy(Co1− x Mn x )2 alloys (x =0, 0.02, 0.04, 0.06, 0.08, and 0.1) have been prepared by arc-melting method. All samples crystallize in single phase with C15 cubic MgCu2-type structure. The nature of phase transition was determined by the results of Arrott plots and Ac susceptibility, and no first order phase transition was observed for samples with x ⩾0.02. With the increase of Mn content, Curie temperature increases linearly, while the calculated magnetic entropy change shows an obvious decrease with a broader peak, which could be explained by the change of phase transition type. [Copyright &y& Elsevier]