Advanced Materials Research Vols. 291-294

Abstract: In order to detect the variation of electro-conductive property of polymeric composite under impact loading, a modified split Hopkinson pressure bar (M-SHPB) is suggested. Such M-SHPB is constructed by designing a new test electrocircuit, and connecting it to the specimen and oscillograph. On the other hand, a copper foil cover is designed and placed on the whole SHPB equipment for avoiding interference of electromagnetic wave existing in the testing environment. By means of M-SHPB, the relation between the resistance and dynamic strain is effectively detected.

Abstract: Several chemical corrosives which show the microstructure of Cr13 stainless steel are prepared. The paper introduces their methods and conditions of use and compares to their corrosive effects. The results indicate that corrosive which contains copper salt can make microstructures displaying clearly and have good reproducibility. In addition, it also has others advantages, for example, operation method and formula is simple and it can be preserved for long time. The paper provides convenient conditions for stainless steel optical microscope analysis.

Abstract: Flux pinned effect (FPE) takes place in high-temperature superconductors (HTSC) when being cooled below critical temperature in magnetic field and appears the self-stable with resisting the disturbing and recovering the initial equilibrium position , even in the failure of control, which is ideal for the activities of spacecraft. In order to investigate the special phenomenon, the image-dipole model (IDM) for interaction and spring-damper model (SDM) for system are adopted in this paper. IDM are based on two assumed images and SDM linked with flux-pinned interface is based on virtual spring and damper. Two models effectively deal with the flux-pinning and give some clear expressions. When moving along single orient, this paper demonstrates the pairs’ self-stability based on two models.

Abstract: Many factors result in pipe collapses under certain external pressure. The relations among them have been studied by the pipe collapse tests. This pepper focused on the test analyses of steel pipe collapse resistance. Those include a pipe collapse pressure test under external pressure and illustrate both test and preparing theoretical analysis, and results of the collapse pressure with the effects on the tendency of ovality. In addition to various pipe collapse data and mechanical test methods, this study will offer a summary of the findings for the further intention of theories researches.

Abstract: This paper presents the design method of a novel biomaterial impedance analyzer based on digital auto balancing bridge method. The system hardware mainly consists of FPGA, ADC, DACs and operational amplifiers. Many DSP algorithms such as direct digital frequency synthesis (DDS), digital phase sensitive demodulation (DPSD), digital modulation and digital filter are implemented in FPGA to realize the auto balancing function of the bridge circuit. Simulation results show that the system has good performance from low frequency to 10MHz. It is suitable for EIS application in biomaterial analysis.

Abstract: Fabric non-iron pleat plasticity is a shaping element of garment. In order to better grasp the performance, its quantitative evaluation method was designed in the paper. It was believed that fabric non-iron pleat plasticity was actually the crease retention of fabric, therefore, crease retention ratio was used for characterizing the fabric non-iron pleat plasticity. The results showed that, all of "PTT shape memory fabrics", PET imitation memory fabrics and cotton fabrics had higher crease retention ratios; followed by Nylon fabrics, next was silk fabrics; wool fabrics had the smallest crease retention ratios. The results proved that crease retention ratios of different kinds of fabrics differ substantially, and the index could basically reflect the non-iron pleat plasticity of different kinds of fabrics.

Abstract: Dual laminated core models for determining exciting power (or/and specific total iron loss) and over saturation characteristics occurred at joints and silicon steel sheet was proposed and prototyped. Calculation method of exciting power at joints of transformer was presented. The saturation characteristics of laminated silicon steel sheets was obtained and analyzed. The model also can be used to investigate the relevant electromagnetic behavior of laminated core in detail.

Abstract: This paper introduces an approach of novel principle to measure the directional emissivity of material surfaces direct. The value of the infrared directional emissivity is obtained by comparing the surface spectral emissivity of testing samples to a blackbody reference. Weak signals are measured with pyroelectric detector by optical modulation and phase-locked amplified technologies. Our experiment is implemented with stainless steel in circumstance of 20 - 300°C, the testing sample is 8µm- 14μm. Compare to the reference and the calibration value without a cooling process, combined uncertainty is less than 0.04, and the result is satisfied.

Abstract: A new electromagnetically induced acoustic emission technique (EMAE) is presented in this paper. It does nondestructive detection with the effect of dynamic electromagnetic loading to generate a stress field stimulating stress waves from the defects. Theoretical analysis and experiment of the EMAE is carried out. The large pulse current generator which is used in electromagnetically induced acoustic emission (EMAE) is designed based on the energy storage of the capacitor. Applying to the EMAE experiment, it can achieve the expected effect and locate the defect in the aluminium plate. This work laid a good foundation for the engineering application of EMAE.

Abstract: Conduct simulative adsorption experiment with lubricating oil containing anticorrosion additive and axletree, measure the variation of which represents the absorption of anticorrosive on the surface of friction pairs, and then testify the adsorptive function of anticorrosive on the surface of friction pairs; By the adsorptive experiment conducted on lubricating oil containing anti-wear additive, find out that the competitive adsorptive relation between anti-wear additive and anticorrosive.