Papers by Author: Wen Qiang Zhang

Abstract: In this paper, microorganism cells (Spirulina platens) were used as forming templates for the fabrication of the helical functional particles with standard shape by electroless silver plating method. The cell form, components and the dielectric properties were observed and analyzed using various tools including optical microscopy, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and vector network analyzer. The results indicate that the silver coatings on the surfaces of spirulina platensis cells are continuous and compact. The coating thickness of the cells increases with increasing plating time and load, in turn resulting in the increase of the dielectric constant. Furthermore, when the coating thickness is larger than 0.42μm, the samples exhibit significantly percolation phenomenon, indicating that the cells deposited silver form conductive network or electron tunneling in the composites.

Abstract: The PPO films with ordered structures have many potential applications in electronics, optics, separation, etc. Its self-supporting film with regular pores is prepared by evaporating the polyphenylene oxide (PPO) solution in carbon bisulfide under humid ambience. It is demonstrated that the nucleation, growth and ordered packing of water droplets condensed on the PPO solution layer as templates in the process are crutial for high-quality honeycomb films. The humidity, concentration, spreading volume of the PPO solution and the direction of airflow have great impact on the pore size, regularity of the film and so on, which are clarified by experiments.

Abstract: In order to fabricate flake-shaped core-shell micro particles (FCMP) with light weight efficiently, deposition on diatomite was carried out by thermal decomposition. The deposition of Fe on diatomite was accomplished by thermal decomposition of pentacarbonyl iron (Fe(CO)₅). The scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) are used to make clear their morphology microstructure, chemical composition, and crystal structure. The average diameter of FCMP is around 40μm, and the average aspect ratio is over 15. The main chemical composition of the FCMP is Fe, Si, Oand C. The XRD result revealed that crystal structures of the FCMP is close to α-Fe. The vibrant sample magnetometer (VSM) result revealed that the FCMP belong to soft magnetic material. The density test results show that the density of FCMP is close to the 2.6, which is lower than the density of pure carbonyl iron powder.

Abstract: Micro-composite sol-gel coating was introduced into bio-limited forming technology for the first time, and the feasibility of the micro-composite sol-gel coating on microorganism was verified. The composite coated microorganism was observed by using optical microscopy. The results showed that the micro-particles of carbonyl iron could remain being fixed on the surface of cells of spirulina platensis by sol-gel process after repeated washings and collections and by using second sol-gel process the micro structures of microorganism would be kept well after drying. The co-deposition mechanism of the composite coating was also discussed.

Abstract: The nano-composite electroless coating was introduced into bio-limited forming technology for the first time, and the feasibility of the nano-composite electroless coating on microorganism was verified. The composite coated microorganism was analyzed by using optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results showed that stirring method would make significant effect on the content of nano-particles in the composite coating. And compared with mechanical stirring, the magnetical stirring makes the content of Fe in the composite coating increase almost twice. The co-deposition mechanism of the composite coating was also discussed.