Applied Mechanics and Materials Vols. 110-116

Abstract: We study the dispersive correction to the finite temperature Casimir force acting on a pair of plates immersed in a magnetodielectric medium. We consider the case where both the plates are perfectly conducting and the case where one plate is perfectly conducting and one plate is infinitely permeable. Although the sign and the strength of the Casimir force depend strongly on the properties of the plates, it is found that in the high temperature regime, the Casimir force has a classical limit that does not depend on the properties of the medium separating the plates.

Abstract: CdS-intercalated bentonite was prepared by an in situ solid-solid reaction and mixed with artificial graphite, polytetrafluoroethylene (PTFE) and carboxymethyl cellulose (CMC) in an appropriate ratio to construct a novel, potentiometric sulfide ion selective electrode. Apart from its good selectivity, the electrode is low cost and good precision.

Abstract: This research is aimed to synthesize titanium nitride (TiN) thin films on stainless steel 304 using metal vacuum arc surface coating technique. A titanium rod is used as cathode. Plasma is generated by applying the arc pulse voltage of 450 V between the electrodes in N2 atmosphere. The pressure of N2 is varied from 10-5 to 10-3 torr when compare with uncoated-stainless steel 304. The bias voltage for substrate is -1 kV. Then the properties of the films are investigated. Firstly, microstructures of TiN thin films are indentified by X-ray diffraction method (XRD) and the cross-section scanning electron microscopy (SEM) is used to measure the thickness. Secondly, the corrosion resistance is examined by electrochemical test in 1 M H2SO4 solution at 25°C. The electrical resistivity is analyzed by interfacial contact resistance measurements.

Abstract: According to different type tactical missile warhead, structure of which was equivalent to charges covered by single-shell or double-shell. The shock initiation response of cast TNT charges, covered by single-shell and double-shell casing impacted by hypervelocity fragment was investigated using non-linear dynamics software AUTODYN. Results shows that in hypervelocity impact conditions, the first layer of double-shell charge imposed severe breaking effect to fragment and generated debris clouds, then the surface impulse density of fragment to rear shell reduces significantly. When impacted by same mass, shape, velocity projectile, deflagration will occur for single shell charges, however, no deflagration can be observed for double shell charges with the same thickness.

Abstract: This calculation focus on the effect of Coulomb interaction U and exchange interaction J on spin magnetic moment M_s of MnO by using the local spin density approximation plus the Coulomb interaction (LSDA+U) method within full potential linear muffin-tin orbital (FP-LMTO). Our calculated results indicated that the spin magnetic moments correlated to U and J. The relevant results exhibited the increasing spin magnetic moments with increasing Coulomb interaction and exchange interaction. Furthermore, equation of spin magnetic moments, which good correspondence to the experimental data, were obtained and the relation of U and J parameter was defined.

Abstract: We utilize photonic crystals to enhanced lighttrapping in a-Si:H thin film solar cells. The photonic crystals effectively increase Haze ratio of glass and decrease reflectance of a-Si:H solar cells. Therefore, increase the photon path length to obtain maximum absorption of the absorber layer. The photonic crystals can effective in harvesting weakly absorbing photons with energies just above the band edge. We were spin coated UV glue on the glass, and then nanoimprint of photonic crystals pattern. Finally, used UV lamp was curing of UV glue on the glass. When the 45∘composite photonic crystals structures, the haze was increase to 87.9 %, resulting the short circuit current density and efficiency increasing to 13.96 mA/cm2 and 7.39 %, respectively. Because 45∘composite photonic crystals easy to focus on the point of light lead to the effect of scattering can’t achieve. So, we designs 90∘V-shaped photonic crystals structures to increase scattering. When the 90∘V-shaped photonic crystals structures, the Haze was increase to 93.9 %. Therefore, the short circuit current density and Efficiency increasing to 15.62 mA/cm2 and 8.09 %, respectively. We observed ~35 % enhancement of the short-circuit current density and ~31 % enhancement of the conversion efficiency.

Abstract: A pseudo-spark based high repetition pulse generator is used, and a rapid charger (3μF) is used for repetitive discharge, and the frequency of typical discharge is 10 kHz. The pulse generator can provide pulse with duration of 1~2μs, which can be generated at 10~100 kHz maximum repetition rate in burst mode, with amplitudes up to 140 kV and 7 J of energy per ignition pulse. This paper studies the changing laws of voltage and current in TPI under different electrodes and discharge voltages. The result indicates that the use of screw thread electrode can increase the discharge times of TPI, reduce applied voltage without reducing the peak burst power. With the same time, TPI can raise the pulse energy and reduce pulse time by increasing voltage.

Abstract: Metal nanocatalysts, as the anodic materials, have become increasingly important in fuel cells due to their unique physical and chemical properties. Here we report the ordered mesoporous carbon (CMK-3) supported silver nanocatalysts have been prepared through the wet chemical reduction by using the reduction of formaldehyde. The electrochemical properties of the Ag/CMK-3 nanocatalysts for formaldehyde oxidation are studied by cyclic voltammograms (CV) and chronoamperometric curves (i-t) in alkaline aqueous solutions. The results show that the peak current density (from CV) of the Ag/CMK-3 electrode is 112 mA cm-2, above 2 times higher than that of Ag/XC-72 at the same Ag loading (14.15 μg cm-2). Furthermore, the i-t curves demonstrate that the Ag/CMK-3 nanocatalysts are efficient and stable electrocatalysts for anodic oxidation of formaldehyde in alkaline solutions. Our results indicate that the application potential of Ag/CMK-3 nanocatalysts with the improved electrocatalytic activity has far reaching effects on fuel cells and sensors.

Abstract: The effect of propanetriol on the electrochemical properties of nanofumed silica gel of Valve-regulated lead-acid (VRLA) batteries have been investigated by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), transmission electron microscope (TEM) and linear sweep voltammetry (LSV). The results show that with the adding of propanetriol the redox peak current density of the lead electrode greatly increases and the reaction resistance reduces obviously. Additionally, the oxygen reactions take place less easily in the gels containing propanetriol. The content of the additive propanetriol also relates with the gel properties. It is proved that the electrochemical properties of gel contained excessive propanetriol (4wt. %) are not as good as that contain 1wt.%~3wt.%.

Abstract: A novel disposable screen-printed immunosensor for rapid determination of highly sensitive C reactiveprotein (hs-CRP) in human serum has been developed in the experiment. The sensor was constructed on one screen-printed carbon electrode (SPCE) with HRP labeled anti-hs-CRP antibody functionalized Fe₃O₄@Au magnetic nanoparticles (HRP labeled anti hs-CRP/ Fe3O4@Au) as the biorecognition probes attracted on the surface of Fe (III) phthalocyanine (FePc)/ chitosan membrane modified screen-printed carbon electrode (SPCE|FePc/Chit/chitosan) by external magnetic field. FePc was acted as electron immediate. The modified electrode shows an excellent electrocatalytic activity for hs-CRP in phosphate buffer solution (pH=7.0). After the immunosensor is incubated with hs-CRP antigen solution at 37°C for 20 min, the access of activity center of the HRP to electrode is partly inhibited, which leads to a linear decrease of the catalytic efficiency of the HRP to the reduction of immobilized FePc by H2O2 at –50 mV in hs-CRP’s concentration ranges from 1.2 to 200 ng/mL. The detection limit was 0.5ng/mL. The immunosensor was successfully utilized for determination of hs-CRP in real serum samples of heart disease patients, whose results were consistent with that by ELISA method. The accuracy and precision of the assay were 91.5-104.4% and 15.8-24.4%, respectively. The immunosensor was reusable once constructed and can be regenerated by adding new nanoprobes on the surface of basal electrode through magnet on its bottom. It can greatly reduce the detection cost which is valuable for the early diagnosis of tumors.