Advanced Materials Research Vol. 669

Abstract: The piezoelectric ceramic has inverse piezoelectric effect, which can be used in the manufacture of the mold internal compensation-driven. We design a multilayer structure with built-in array of piezoelectric ceramic to achieve active deformation to compensate the tool-shaped face. A piezoelectric micro-displacement compensation model is proposed based on the inverse piezoelectric effect of piezoelectric ceramic. According to the initial face error of tool or from wear, a certain amount of DC voltage is applied on the corresponding area of the piezoelectric ceramic elements to produce certain amount of shrinkage, achieving the goal to adjust tool surface. Based on this theory, we develop a device with active deformation compensation and propose an optimization algorithm of applied voltage.

Abstract: Currently, the fabrication of electrodes for microchip electrophoresis (ME) is rather complex. Usually, the electrodes have not been integrated completely with ME, which often lead to poor efficiency and reproducibility for the surface contamination. In this paper, we design and develop a new method for miniaturization of electrodes for ME. And the integrated microelectrodes show good detection performance for the ME analysis of ascorbic acid.

Abstract: Zn1-xMgxO (x=0, 0.05, 0.1, 0.2 and 0.3, respectively) thin films have been synthesized by sol-gel method on glass substrates. The structure, morphology and optical properties of the samples have been studied by X-ray diffractonmeter (XRD), scanning probe microscope, UV-visible spectrophotometer, fluorescence spectrophotometer and spectroscopic ellipsometer, respectively. The XRD result shows that all the films have hexagonal wurtzite structure; no phase segregation is observed. The surfaces of Zn1-xMgxO thin films are smooth and the root mean square (RMS) roughness of the samples is only several nanometers. The transmittance spectra reveal that all samples have high transmittance above 90%, with Mg doping content increase, the optical band gap increases from 3.27eV to 3.77eV. The photoluminescence spectra show that all samples have two emission peaks in ultraviolet and violet region, a blue shift of ultraviolet emission is observed. The refractive indexes of all samples decrease with the increase of wavelength ranging from 350nm to 900nm. The refractive index changes apparently by varying Mg content, which has potential application in research of optical materials and the design of optical devices.

Abstract: Zinc oxide (ZnO) nanorod arrays were fabricated on ZnO:Al seeded Si substrates with various reaction temperatures using a low temperature hydrothermal method. The morphology and structure of ZnO nanorod arrays were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It reveals that the ZnO nanorods grow vertically on Si surface with (002) preferential orientation. The transmittance spectra show the ZnO nanorod arrays fabricated at low temperatures have high transmittance in the visible region and decrease with reaction temperature increasing. Moreover, the same trend was also observed in the reflectance spectra of the ZnO nanorod arrays. The optimal reaction temperature is of 120 °C for ZnO nanorod arrays with high transmittance (~80%) and low reflectance (~10%) in the visible region. The superior optical properties make ZnO nanorod arrays promising for applications as transparent electrodes.

Abstract: The fiber shaped monoclinic tungsten oxides with high preferential orientation has been synthesized by dialysis and aging treatment at room temperature, of the white precipitates prepared from HCl acidified (NH4)10W12O41 solution. The microstructure evolution of the above tungsten oxide was studied by SEM. The morphology of the powder changed from irregularity to shuttle plate-like during short time dialysis in pure water, and the butterfly shape was obtained after long time treatment. It was found that the nano-particles were rearranged to form nano-fibers on the surface of the butterfly shaped oxide as a function of aging time when the butterfly powder was kept in the original mother liquor. Compared to butterfly oxide, the morphology of fibers exhibited much improved thermal stability. The photochromic property of the tungsten oxide with different morphology was studied. The response time in color change after irradiated by the UV output of a 30 W mercury lamp is 20 s in inert atmosphere and the recovery time in bleach is about 2 months.

Abstract: LiFePO₄/C cathode materials were synthesized by Sol-gel method under the same process conditions using different water-soluble lithium source (LiOH, Li₂CO₃, LiNO₃). The phase of synthesized powders were characterized by XRD; and the electrochemical performance of the material was investigated by measurements of cyclic voltammetry, AC impedance measurements, charge and discharge. The results show that the synthesized LiFePO₄/C using LiOH as the lithium source has high electrochemical reversibility and low internal impedance. The specific discharge capacity is 147.5mAh/g under the discharge at 0.2C rate. It also has high stability of cycle capacity, and almost no attenuation after 30 cycles. So it has the excellent electrochemical performance.

Abstract: In this experiment, the oxidative damage of nano-CdSeS in mice brains was performed. 20 male Kunming mice were divided into 4 groups and 3 experimental groups were exposed to different doses of nano-CdSeS (0.1 mg/mL, 0.2 mg/mL and 0.4 mg/mL) by intravenous administration while the control used saline solution instead. Three days later, the enzymatic activity of superoxide dismutase (SOD), the content of malondialdehyde (MDA) and the damage degree of DNA were determined to assess the oxidative damage in brain tissues. Our results showed that in the experimental groups, SOD activity was inhibited and MDA content was increased as the doses rising, at the same time, tail moment and tail DNA% increased significantly when comparing with the control. And these results exhibited a certain doses-dependency relations. From results above, it demonstrated that oxidative damage of brain induced by nano-CdSeS which enter into blood–brain barrier in mice.

Abstract: The conventional sensor in bridge structure vibration monitoring field has such disadvantages as high price and poor long-term stability. According to this insufficient, a kind of novel MEMS sensor micro system, which can be used to real-time monitor the structure vibration of large span bridge, is developed. For such system, the sensing element structure of 3D-MEMS is designed. The theoretical model of sensing test is established. And the three level packages, which are chip level, device level and micro-system level, is completed. The data acquisition system based on this sensor is developed. And this kind of sensor system has been applied to the structure health monitoring of the Yellow River bridge of Zhengzhou and the Yangtze River bridge of Wuhan to measure the horizontal, vertical vibration and acceleration signals. The measuring results show that this sensor micro-system has such advantages as good long-term stability, strong anti-interference ability, and high test sensitivity up to 2V/g. As it is simple, this test system can greatly reduce the testing cost.

Abstract: Polypyrrole nanoparticles (PPy NPs) were successfully prepared in one-step by a reactive-template method. Fe3O4 NPs were selected as the reactive-template, and they acted as both templates to shape structure of PPy NPs and initiator source, simultaneously. No surfactants were used in whole process, which dramatically improved the purity of resulting products. HCl solution concentrations played an important role on the morphologies of resulting PPy NPs.

Abstract: Zn1-xCdxS alloy nanoparticles have been prepared via solvothermal approach. The effects of the mole fraction of Cd on the nanoparticles’ structure, size and photoluminescence spectra were investigated. It shows that with increase in mole fraction of Cd, the lattice structure of Zn1-xCdxS changes from cubic to hexagonal, and the size of these nanoparticles varied within 6-40nm. Room temperature photoluminescence measurements show an intense red shift from 518nm to 662nm. And the band gap energies from 2.3 to 3.54eV can be realized for the Zn1-xCdxS nanopartices. Furthermore, it is found that the conversion of Methylene Blue (MB) using Zn0.6Cd0.4S as the photocatalyst was up to 97% after 2h of irradiation.