Applied Mechanics and Materials Vols. 513-517

Abstract: A novel waterborne polyurethane (WPU) modified by tung oil was prepared with 2,4-tolylene diisocyanate, polyethylene glycol, dimethylol propinic acid, 1,4-butanedilo as main materials via acetone process. The structure of WPU molecule was characterized by FT-IR. Adhesive behavior for non-polar and/or low surface energy soft packing films was studied. Water resistance of films were evaluated by water contact angle and water uptake and thermal properties determined by thermal analysis instruments. The results show that the modified WPU films have good water and heat resistance. Both of modified WPUs or not have good adherence on BOPP films.

Abstract: The key factors affecting the efficiency of silicon concentrator solar cells with boron implanted emitters were investigated. It is found that, by optimization of the front metal finger, the efficiency of the solar cells can be improved by approximately 10% under 10 suns illumination with the finger spacing of 330 μm.

Abstract: An electrospraying process was developed for fabricating a new type of microparticulate third generation solid dispersions (SDs) composed of multiple components with ferulic acid (FA) as a model active pharmaceutical ingredient. The spraying fluids were the co-dissolving solutions of FA, polyvinylpyrrolidone K25 (PVP K25) and sodium dodecyl sulfate (SDS) in 95% ethanol aqueous solutions. Field emission scanning electron microscopic observations showed that the microparticles had an average size of 1.47 ± 0.75 μm. Results from the differential scanning calorimetry analyses suggested that FA and SDS were distributed in the polymer matrix in an amorphous status owing to the compatibility among components resulted from the second-order interactions, as verified by attenuated total reflectance Fourier transform infrared spectra. In vitro dissolution tests demonstrated that the microparticulate SDs could release all the contained FA within 1 minute, extremely faster than the raw FA particles. It can be concluded that electrospraying is a useful tool for creating new generation SDs composed of multiple components for enhancing the rapid dissolution of poorly soluble drugs.

Abstract: According to the gas dynamic property of cold spraying, the distance from the outside of nozzle to the substrate has great influence on the coating quality including the thickness of coating and the deposition effeciency. Meanwhile, the effects of particle size on coating quality are of the utmost importance. The influences of two parameters above on the quality of the NiCoCrAlY coating on the magnesium substrate by the experiments of the cold gas dynamic spraying were discussed in this study. The results of the experiments showed that, based on the fact that other parameters were not changed, when the standoff distance was more than 50mm, there were no complete coatings on the surface of the substrate, and its thickness was asymmetrical. When the standoff distance was 25mm, the thickness was homogeneous, and the oxygen content was only 1.3%. Also, when the particle size was 5~50μm, the coating quality was better.

Abstract: The purpose of this study is to investigate the undrain shear strength increment during consolidation process of soft clayey soils. Thirty kinds of laboratory triaxial tests have been performed using undisturbed and remolded Ariake clay samples with different degree of consolidation and 5 kinds of confining pressure. Test results show that well known linear equation proposed by Yamanouchi et al.(1982) is overestimated the strength of undisturbed soft clay ground in the process of consolidation. A new simple and reasonable exponential equation proposed in this paper.

Abstract: We have measured the Raman spectra of all samples in the process of preparing polyacrylonitrile (PAN) iron complex nanofibers, and compared their Raman spectral characteristics, and thus gained a preliminary result for the PAN nanofibers structural changes in the different stages. Through its Raman spectral analysis and comparison we can find that the cyano group (C N) of modified PAN nanofibers disappeared while the Raman bands of C = N group appeared. For the pre-oxidized PAN nanofiber, because the D and G bands of the C = C vibration appeared in the Raman spectra, it is concluded that the PAN nanofiber has an apparent structural change. Finally, it is also found that that Fe³⁺ and O^2- ions have formed coordination bonds in the further prepared PAN iron (Fe³⁺) complex nanofibers because the characteristic Raman band of Fe = O bond appears.

Abstract: Porous hexagonal plates of hydrohausmannite were prepared by a simple hydrothermal method. Morphology control of the product was easily achieved by adjusting the experimental parameters. The selected area electron diffraction (SAED) patterns show obvious evidence that these hexagonal plates were formed by oriented aggregation-based growth of subunits, which is discussed in details. Intriguing well-shaped hexagonal pores were obtained when the hexagonal plates were exposed to high intensity electron beam irradiation. These hexagonal plates of manganese oxide may have wide applications as components and/or interconnect in nanodevices and/or as nanotools.

Abstract: A variety of electrical apparatus used in daily life can cause fires because of internal or external factors. During cause identification of an electrical fire, the first short circuit melted marks of copper wire have been considered highly important because they are direct proofs. Additionally, overloaded short circuit caused by the overload of current due to excessive electrical usage can give rise to an electrical fire. Despite extensive research on the first short circuit in fire scenes, the overloaded short circuit remains difficult to be distinguished because of the limitation of commonly used testing methods. Conventional metallographic method is intuitionistic and simple, but may not provide detailed data of crystals such as misorientation of grains. Here a new method (electron backscattered diffraction, EBSD) is applied for identification of the first and overloaded short-circuited melted marks of copper wires in electrical fire scenes. Results show obvious morphological distinctions in melted marks of copper wires between the first and overloaded short circuits. Qualitative and Quantitative differences obtained from the contrast of the above two short circuit situations may assist for cause identification of electrical fires in the future.

Abstract: SnS thin films were deposited at different temperatures on silicon and quartz plates through directly elementary reaction via a simple chemical vapor deposition (CVD) process. The as-prepared products have a transformation of morphology from plate-like to granule-like when the temperature increased. A mechanism involving two competitive factors, surface energy and binding energy, was proposed to understand their growth. The products prepared at low temperature were single crystal while the films made in high temperature are polycrystal, the optical band gap (1.2~2.1ev) and the Sn:S atom ratios increases as the deposited temperature increases.

Abstract: The reaction of oxygen atom with difluoric methyl radical has been studied using DFT method at 6-311++g** level. All the geometries, vibration frequencies and energies of different stationary points are calculated by B3LYP/6-311++G** and the results agree with the experimental values. The relationship and the changes among them can confirm the mechanism of the reaction and the process of electron transfer. Through the analysis, the major reaction channel and the minor reaction channel are confirmed.