Applied Mechanics and Materials Vol. 421

Abstract: well-aligned ZnO nanorod arrays (ZNRAs) grown on the ZnO seed layers coated p-silicon (p-Si) substrates in various times from 1.5 to 5 hr have been fabricated from aqueous solutions at low temperature. Morphologies, crystalline structure and optical transmission were investigated by a scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. The results showed that ZNRAs grew vertically from the substrates, having uniform thickness and length distribution, the average diameters and length of ZnO nanorods increased with increasing growth time below 3 hr. The XRD results showed that ZnO nanorods were wurtzite-structured (hexagonal) ZnO.

Abstract: Paper-based microfluidic devices have recently received increasing attention as a potential platform for its low cost, portability and excellent compatibility with biological samples. A variety of fabrication technologies were employed, including simple photolithography, wax plotting, printing, inkjet etching, plasma etching and so on. Meanwhile, the potential applications of paper-based microfluidic devices in diagnostic, point-of-care (POC), and environmental monitoring were reported. We review the recent progress of fabrication technologies and the applications of paper-based microfluidic devices.

Abstract: Retracted article: This work aims to enhance the adhesion of Parylene-C (poly-chloro-p-xylylene C) thin film on PMMA, Glass and Aluminum substrates by chemical vapor deposition, surface improvement and treatment of substrate as well as analysis of film on Glass, PMMA, Aluminum and its surface adhesion by dipping under A-174 silane solution and conducting on plasma treatment (18 W). The results show that: (1) After oxygen-plasma pretreatment, the surface roughness of the 200nm-thickness film on glass substrate specimens decreases from 18nm to 7nm. (2) After dipped in prescription solution pretreatment, the residual stress reduces from 107MPa to 64MPa on glass substrate specimens. (3) The critical load of 600nm-thickness film increases from 14.1 to 18.5mN, showing the substrate after dipped in prescription solution pretreatment can improve the adhesion of the Parylene-C thin film on flat glass substrate specimens.

Abstract: Fly ash-based geopolymers are new binding materials produced to replace the ordinary Portland cement (OPC) used in concrete. In this research, the effect of alkaline activators on the compressive strength and the microstructure of low-calcium (Class F) fly ash-based geopolymers were studied. Fly ash and the alkaline activator were mixed with alkaline activator to fly ash ratios of 0.30, 0.35, and 0.40 at a constant ratio of water glass (sodium silicate) to sodium hydroxide (NaOH). The alkaline activator solution was prepared by mixing water glass with a 15 M NaOH solution. The samples were cured at a temperature 70 °C for 24 hr and maintained at room temperature until the testing was conducted. The test results indicated that the compressive strength increased when the ratio of alkaline activator to fly ash was increased at 7 days. The ratio of 0.4 produced the maximum compressive strength, which was 8.61 MPa. This was due to high reaction rate between the fly ash and the alkaline activator solution. Morphology studies, conducted by SEM analysis of the geopolymer samples, indicated that geopolymers synthesized at a ratio of 0.4 also had the most homogeneous and less porous microstructures, which was attributed to the high dissolution of the fly ash particles in the alkaline activator solution. The microstructure appearance of geopolymers treated heat temperature of 400, 600 and 800°C, shows a sintering process takes place for unreacted fly ash microspheres. It was observed as an overall, the visible microcracks formed on the surface of the highest compressive strength geopolymers only, was due to loss of water during heating.

Abstract: Because plenty of polymers have been added in the surfactant/polymer (S/P) flooding fluid, its viscosity becomes higher. So when S/P flooding fluid flows in the stratum, its threshold pressure gradient is an important influence factor. According to study S/P flooding fluid with different viscosities that flows in different permeability cores, the variation laws of seepage curve have been obtained. The results of the study show that the seepage of S/P flooding exhibits nonlinear seepage in low velocity, and changes gradually to linear flow as the pressure gradient rises. As well, S/P flooding has obvious threshold pressure gradient when its speed is low. The threshold pressure gradient of S/P is related to the permeability of the core and its own viscosity. The higher the viscosity, the lower the permeability of the core, the threshold pressure gradient will be greater.

Abstract: Based on the (Gly4Ser)3 linker, the esat-6 and cfp-10 gene were fused for raising the antigenicity of single antigen. The DNA fragments of esat-6 and cfp-10 were fused by splicing by overlapping extension (SOE) polymerase chain reaction (PCR),and the fusion gene esat-6-cfp-10 were cloned into pMD18-T vector, and then we got the recombinant plasmid pMD-esat-6-cfp-10. pMD-esat-6-cfp-10 and pET28a (+) were digested by BamHI and EcoRI double enzymes. The purified mpb esat-6-cfp-10 fusion gene was subcloned into the expression vector pET28a (+),and the prokaryotic expression vector pET-esat-6-cfp-10 was constructed. Plasmid containing pET-esat-6-cfp-10 was transformed into competence Escherichia coli BL21(DE3).The bacterium was induced by isopropyl-β-D-thiogalactopyranoside (IPTG) and analyzed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE),approximately 25 kDa exogenous protein was observed on the SDS-PAGE. The protein was analyzed by using Western-blotting. The results indicated that the protein was of antigenic activity of Mycobacterium bovis. These results could serve as a basis for further studies on the usefulness of the fusion gene and its expression product in the development of DNA vaccine; living carrier vaccine; subunit vaccine and diagnostic reagents against bovine tuberculosis.

Abstract: This study presents a compound process combining composite electroforming with wire Electrical Discharge Machining (w-EDM) for developing a thin cubic boron nitride (CBN) grinding-tool. A precisely designed set-up in which a small compound depositing tank providing effectual convection of a compound electroplating solution to help fabricate a CBN grinding-blank is presented. A funneled entrance design for converging CBN grits in the working tank and creating a depositing effect on the substrate is employed and proposed. Considerable micro CBN abrasives are evenly embedded into the nickel-based coating layer, which offers enough abrasives for grinding-edge. Subsequently, the coated grinding-blank is trued and dressed by using w-EDM to form a multiple thin CBN grinding-tool. Experimental results indicate that the electroforming process can create a Ni-based CBN layer of high-integrity under current density of 2 ASD and concentration of 8.6 g/l CBN grits. Moreover, the CBN grinding-edge of 10 μm in thickness (each edge) can be achieved.

Abstract: A conductive DBR electrode fabricated using the single Indium tin oxide (ITO) conductive material is proposed. The high refractive index of the dense ITO film was achieved by RF sputtering at room temperature and the porous ITO film with low refractive index was prepared by applying supercritical CO₂ (SCCO₂) treatment at 60 °C on gel-coated ITO thin films. The index contrast of the ITO bilayers was higher than 0.5 at a wavelength of 550 nm. In addition, small deviations on the optical thickness of the ITO bilayers were observed during the DBR stacking processes. For the DBR comprising 4 periods ITO bilayers, the reflectance and sheet resistance of 72.8% and 35 Ω/ were achieved.

Abstract: This paper based on the analysis of the regional geological background of Maoping Pb-Zn deposit and made a comprehensive interpretation to the linear structure in this area through ETM+ remote sensing image. It used linear orientation statistics, linear density statistics, linear structure intensity statistics, linear structure intersection density statistics and so on to make a quantitative analysis to the linear structure characteristics of this area. We can extract the main linear structure azimuth, main lineament development zone and secondary lineament development zone. It made a quantitative research to the linear structure information of the remote sensing interpretation in this area.

Abstract: Huize Pb-Zn deposit is located in the transfer part of Tethys Himalayan tectonic domain and the Pacific tectonic domain. This research used Landsat7 ETM+ remote sensing image with 30m spatial resolution. Based on the true color composite image with Band 321, we get the linear structure interpretation figure supplemented by spatial filtering processing. From the distribution regulation in radar chart of lineaments orientation and contour map of the density for the linear structure, we can see that the dominant structure orientation are NE and NW. They are consistent with basic structural pattern of Huize Pb-Zn deposit from a quantitative point of view. This indicates that a linear structure interpreted results can objectively reflect the regional tectonic features, so it is true and reliable.