Papers by Keyword: PA

Abstract: Increasing waste streams of carbon fibers (CF) and carbon fiber reinforced plastics (CFRP) lead to increasing need for recycling and to growing amounts of recycled carbon fibers. A main issue in current research for carbon fiber recycling is the reuse of regained fibers. Carbon staple fibers such as recycled fibers hold big potential for mechanical properties of lightweight parts, if used properly. Applying recycled CF (rCF) as milled reinforcement fibers or as nonwoven in carbon fiber reinforced plastic leads to a poor yield of mechanical proper due to low fiber orientation, limitations in fiber volume content or due to short fiber length. The rC staple fiber tape presents a more efficient approach. Recycled carbon fibers are blended with 50 wt. % thermoplastic nylon 6 fibers and processed through a roller card to a sliver, which is a linear fibrous intermediate. The sliver is continuously drawn, formed, heated and consolidated to the thermoplastic rC staple fiber tape. The tape is similar to common carbon fiber tapes or to continuous tows but has different positive properties, such as high fiber orientation, homogeneous blend of fiber and matrix and suitability for deep drawing.

Abstract: Universal serial bus is put forward by seven corporations which are led by the Intel. It cost lowly, fast and easily expandable. USB is widely used in serial communication interface, widely used in computer peripherals and digital products. The USB protocol layer is the core unit of the USB device, which handles most of the contents of the USB protocol provides. This paper studies USB protocol layer design and implementation. Then USB protocol layer is completed based on FPGA.

Abstract: Nonlinearity of power amplifier always results in spectrum spreading on input signal. When using digital predistortion technology to compensate power amplifier's nonlinearity, the required sampling frenquence for the output signal of amplifier is times of the original signal. The undersampling predistortion method can reduce the sampling frequency requirements. However, for the broadband signal, due to the significant memory effect of the power amplifier, the performance of undersampling digital predistortion is not satisfactory. In order to improve the undesirable predistortion performamce, this paper presents two kinds of undersampling digital predistortion compensation methods. For different sampling frequencies, the predistortion performances of these two kinds of compensation methods are different.

Abstract: The mechanical and tribological properties of PA6/PPS blend reinforced by different content of carbon fiber were studied in the manuscript. It was found that the strength, modulus and hardness of PA6/PPS blend is improved apparently though breaking elongation rate and impact strength decreases to some extent. Average friction coefficient value of the carbon fiber reinforced PA6/PPS (PA6/PPS-CF) composites at the state stage is lower than PA6/PPS blend and PA6/PPS-CF10% exhibits the lowest friction coefficient of 0.34. As the content of carbon fiber increases, wear rate of the PA6/PPS-CF composites trends to increasing. These results is useful for providing some practical guidance for the application of polymer materials in the tribological field.

Abstract: Based on detailed consideration of the autonomic healing concept of microencapsulated healing agent, micro- bacteria induced calcite and shape memory alloys, our research team proposed a new self-healing technique coupled with of SMA and heat-melt adhesive. In this article, chemical stability and bonding strength with cementitious materials of PA heat-melt adhesive were tested. Experimental results show that PA heat-melt adhesive may contain the ability being used in self-healing techniques coupled with SMA.

Abstract: The Macroporous Nanocrystalline TiO₂ Thin Film Was Prepared by Dipping-Coating Method. Polystyrene (PS) Microspheres Template Was Used as Pore-Forming Assistant and TiO₂ Sol Was Used as Precursor. the Photoelectric Characteristics of the Samples Were Studied Using Surface Photovoltage (SPV) and Photoacoustic (PA) Techniques. the Presence of a Small Amount of Residual Template Damages the Integrity of the Porous TiO₂ Film with Inverse Opal Structure, and TiO₂ May Be Restricted in Certain Application Fields as Photonic Crystals. a Small Amount of Residual Template Changes the Surface Photovoltaic Properties of the Porous TiO₂ Film, Resulting Mainly in the Broadened Scope and the Increased Intensity of SPV Response.