Polypyrrole Chitosan Cobalt Ferrite Nanoparticles Composite Layer for Measuring the Low Concentration of Fluorene Using Surface Plasmon Resonance

Fluorene is a polycyclic aromatic hydrocarbon, which is a hazardous toxic chemical in the environment. The measurement of low concentrations of fluorene is a subject of intense interest in chemistry and in the environment. Polypyrrole chitosan cobalt ferrite nanoparticles are prepared using the electrochemical method. The prepared layers are characterized using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The layers are used to detect fluorene using the surface plasmon resonance technique at room temperature. The composite layer is evaluated after detection of fluorene using atomic force microscopy. The fluorene is bound on the layer, and the shift of the resonance angle is about 0.0052°, corresponding to the limitation of 0.01 ppm.

Effects of NPB anode buffer layer on charge collection in ZnO/MEH-PPV hybrid solar cells

We investigate the effects of （N,N’-diphenyl）-N,N’-bis（1-naphthyl）-1,1’-biphenyl-4,4’-diamine （NPB） buffer layers on charge collection in inverted ZnO/MEH-PPV hybrid devices. The insertion of a 3-nm NPB thin layer enhances the efficiency of charge collection by improving charge transport and reducing the interface energy barrier, resulting in better device performances. S-shaped light J–V curve appears when the thickness of the NPB layer reaches 25 nm, which is induced by the inefficient charge extraction from MEH-PPV to Ag. Capacitance–voltage measurements are performed to further investigate the influence of the NPB layer on charge collection from both simulations and experiments.

Express Methods for Measurement of Electroconductivity of Semiconductor Layered Crystal

We describe theoretically the grounded method of measuring the conductivity of anisotropic layered semiconductor materials. The suggested method implies the use of a four-probe testing device with a linear arrangement of probes. The final expressions for identifying the electrical conductivity are presented in the form of a series of analytic functions. The suggested method is experimentally verified, and practical recommendations of how to apply it are also provided.

A study of measuring acoustic velocities of thin and hard sea-bed layers

It has been known that the error of measuring acoustic veloicities of thin sediment layers by the well-known T2-X2 approach is usually untolerable, and that this approach is unavailable in the case where sea-bed is hard because no echo from any subsurface below sea-bottom can be received. Therefore applying the ray-parameter method to thin layers and the refraction method to hard layers need to be considered in an acoustic velocity measurement system composed of a sound source and a towed hydrophone streamer. Some problems of practical importance about the applications of the two methods, such as echo-data processing procedures and error estimations in measuring acoustic veloicities, are discussed, and the effectiveness of theoretical analyses has been verified through computer simulations.

Method for utilizing PIV to investigate high curvature and acceleration boundary layer flows around the compressor blade leading edge

Particle Image Velocimetry(PIV)is a well-developed and contactless technique in experimental fluid mechanics,but the strong velocity gradient and streamline curvature near the wall substantially limits its accuracy improvement.This paper presents a data processing procedure combining conventional PIV and newly developed Mirror Interchange(MI)based Interface-PIV for the measurement of the boundary layer parameter development in the blade leading edge region.The synthetic particle images are used to analyze the measurement errors in the entire procedure.Overall,three types of errors,namely the errors caused by the Window Deformation Iterative Multigrid(WIDIM)algorithm,the discrete data interpolation and integration,and the wall offset uncertainty,comprise the main measurement error.Specifically,the errors due to the discrete data interpolation and integration and the WIDIM algorithm comprise the mean bias,which can be corrected through the error analysis method proposed in the present work.Meanwhile,the errors due to the WIDIM algorithm and the wall offset uncertainty contribute to the measurement uncertainty.Computational fluid dynamics-based synthetic particle flows were generated to verify the newly developed PIV data processing procedure and the corresponding error analysis method.Results showed that the data processing method could improve the accuracy of PIV measurements for boundary layer flows with high curvature and acceleration and even with significant flow separation bubbles.Finally,the data processing method is also applied in a PIV experiment to investigate the boundary layer flows around a compressor blade leading edge,and several credible boundary flow parameters were obtained.

Thin layer gas electrode and its application to measurement of dissolved oxygen

A novel thin layer cell equipped with thin layer gas electrode(TLGE)was studied as electrochemical gas sensor for the measurement of dissolved oxygen in water or aqueous solutions. The working electrode(TLGE)is a hydrophohic gas diffusing electrode placed between the cell electrolyte and the solution to be tested.The hydrophobic pores in TLGE serve as a gas chamber. After the sampling period,in which the partial pressure of dissolved oxygen in test solution becomes in equilibrium with that in the gas chamber,the TLGE is polarized with square wave or linear potential signal.Then the Faradaic charge (Q) consumed in depletion of the oxygen contained in pores of TLGE is measured.The main merits of this system are good linearity between the partial pressure of dissolved oxygen in test solution and Q,low zero-reading,negligible liquid-gas difference,con- venient calibration and very low temperature coefficient(ca.0.5%/℃).This technique can also be applied to the measurement of oxygen partial pressure in gas phases.

Corrosion Behavior of Rusted 550 MPa Grade Offshore Platform Steel

The corrosion behavior of a rusted 550 MPa grade offshore platform steel in Clcontaining environment was investigated.The results revealed that the corrosion process can be divided into initial stage in which corrosion rate increased with accumulation of corrosion products and later stage in which homogeneous and compact rust layer started to protect steel substrate out of corrosion mediums.On the contrary,structural analysis of rust layers by X-ray diffraction showed that α-FeOOH increased from 1.3% to 3.6% and the Fe3O4 increased from 1.0% to 1.5% while γ-FeOOH reduced slightly according to corrosion time increased from 30 cycles to 73 cycles.The results of electron probe microanalysis indicated that Cr concentrated mainly in the inner region of the rust,inner/outer interface especially,whereas Ni and Cu were uniformly distributed all over the rust after 73 corrosion cycles.According to electrochemical measurements,it was found that the corrosion rate of rusted steel reduced from 0.61 mm/a after 45 cycles to 0.34 mm/a after 85 cycles,44.3% reduction approximately,and Rrust values increased with increment of corrosion time.Therefore,formation of compact inner rust layer and enrichment of Cr are important to improve corrosion resistance of offshore platform steel.