Key Engineering Materials Vol. 464

Abstract: Natural bone is a composite mainly made from nano/micro-structure of hydroxyapatite and collagen fibers. For bone regeneration by tissue engineering, it is important to synthesize three dimension nano-composites with good biocompatibility, high bioactivity and great bonding property as potentially useful scaffold. In this study, we fabricated chitosan nano-nonwoven scaffold via electrospinning and modified chitosan scaffolds by carboxymethylation (CM) to improve the osteoconductive characteristics. Results of FTIR confirmed the existence of carboxymethyl groups of CMChitosan. Moreover by employed mice osteoblast (MC3T3-E1) cell for adhesion, proliferation and differentiation assays, we found that CMChitosan appeared to have effect on the late stages of osteoblast behavior (calcium deposit).

Abstract: In order to release the influence of shedding motion on warp tension fluctuation, easing device is often set on short looms with single back rest system. With the decrease of the beam’s diameter, the wrapping angle formed by warp and the active back rest will become bigger, and the effect of the easing device will be more significant. However, the wrapping angle of the double back rest system is a constant while the change of the beam’s diameter. The effect of easing device on air-jet looms of double back rests system is analyzed in this paper, and conclusion has been made that the easing device can be eliminated on the double back rests system.

Abstract: Speech enhancement is very important for mobile communications or some other applications in car. The energy distribution of signal is the basis of algorithms which denoise noisy speech in time-frequency domain. In this work, the noise regarded is the tire-road noise when driving in expressway. Wavelet packets transform is used in the analysis. After decomposing noise signal and noisy speech signal by wavelet packet transform, the analysis for the difference of the energy distribution between noisy speech and noise is finished.

Abstract: In this paper, polyethylene film was treated by APGDLD (atmospheric pressure glow discharge liquid deposition) to polymerize acrylic acid onto the surface to improve its hydrophilicity. The effect of APGD and APGDLD on the surface modification is compared. Influence of various treatment conditions on polymerization degree and contact angle such as applied voltage, discharge gap, reaction gas flow rate and treatment time were investigated. Treating effect was characterized via contact angle measurements, SEM and ATR-FTIR. The results indicated the hydrophilicity of the polyethylene film surface was enhanced and well reserved by APGDLD.

Abstract: How to master the technology innovation and method and technique in product exploitation, has been always one of the issues of research and discussion. Based on more than 40 years’ experiences of engagement in mechanical and electrical technology on product research, design, teaching, the author proposed and constructed "OF + N" theoretical method (for short: method of creating inventive and innovative topics) suitable for technological innovation and product development. Some innovative design was implemented using the theoretical method through years of research and probe.

Abstract: As a tool of modeling the system of multiple energy, bond-graph theory is applied to the modeling for electric power steering system which is electromechanical hybrid. Bond graph models for C type, P type and R type of EPS dynamic system are built respectively. The CH7140 type of car equipped with C type EPS is taken as a prototype and its maneuverable performance is simulated under typical working conditions. A PID control method with time delay transfer function is adopted to imitate the driver’s operation. Steering maneuverability test of the CH7140 car is conducted. The simulation result is consistent with the test result. It is shown that the bond-graph model of EPS is rational, and simulation model derived from bond-graph is effective which can be applied to EPS and full vehicle steering maneuverability simulation research.

Abstract: Precise pile height is an essential quality measurement for sculptured-style jacquard carpet. Correct yarn tension analysis is the key to accurately control carpet pile height during manufacturing carpet. This paper described a standard tufting equipment system with essential components in the yarn path. The relationship of pile height and pile tension is formulated. The А.П.МИНаКОВ’s Euler formula is introduced into yarn tension modeling which including the yarn guides, sub-line frame, and puller rollers parts. Finally, this tension model is validated by comparing yarn tension simulation result data and experimental measuring data.

Abstract: A novel method for locating the pills in woven fabric based on Gabor filter is proposed in this paper. The process of capturing the fabric image is first introduced and the hardware and software of the system is given simultaneously. Gabor filter is then carried out in the pilled fabric image to remove the fabric texture and enhance the pill information. In the enhanced fabric image, threshold method is used to segment and locate the fabric pills. The location of fabric pills lays the foundation for constructing the whole system of evaluating the fabric pilling grade.

Abstract: The structure and property of pyrocarbon varies widely with different deposition conditions. The isotropic carbon which can only been deposited in the bed of fluidized particles is very important in biomedical fields, for instance, it is often used as the coating of artificial heart valve components. The deposition of isotropic pyrocarbon containing silicon is experimented in fluidized bed over a wide range of deposition conditions. The results show that bed temperature influences strongly average coating rate, coating density, silicon content and coating micro-hardness. Propane concentration has a much effect on coating density, carbon matrix density and isotropic characteristics. Total gas flow rate and inlet dimension of fluidized bed affect the formation of fluidized bed.