Advanced Materials Research Vols. 457-458

Abstract: Chitin is an abundant biopolymer like cellulose that is rather resistant to degradation. In order to develop a bio-digesting method, soil sample in Qinling Mountain were collected for screening the bacteria with high chitinase activity by method of the transparent circle. The strain D5-23 was isolated and screened out from soil, which was found with amazing chitinase acitivity. The ratio of transient circle and colony circle is no less than 10. The strain was then identified as Aeromonas sp according to the sequences of 16S rDNA and morphological analysis. The enzyme activity was studied further, ,data shows that the optimum temperature was 45°C, which is similar to other Aeromonas sp, wheras the optimum pH is 5 and 9, which is more similar to Vibrio alginolyticus TK-22.

Abstract: Chitosan is an aboundant biopolymer like cellose. To bioprocess them with chitin deacetylase (CDA), the products will be used in medicine and food industry. [In order to get new strains with significant ability of (CDA) Twenty eight strains producing CDA were isolated and screened out from the soil samples by color reaction in plate medium. The strain F2-7-3 was screened out from these strains for the highest CDA activity, which can reach more than 250U/mL. The paranitroacetanilide was used as the substrate, the optimum temperature for enzyme activity was determined to be 50°C and the optimum pH was 7.0. It was studied by method of morphological, physiological and biochemical characteristics and 16S rDNA analysis. Data shows that the strain was Rhodococcus sp.

Abstract: With a new kind multi-scale modeling idea for artificial bone implant, the mechanics analysis steps and method were done for further surgical and recover. The multi-scale bone model was built up from CT datum, with which the whole bone stress distribution was simulated by using ANSYS software. The second analysis focuses on the micro structure with the former analysis results. Through compute iteration, the final results can be gotten where the interface stress came to be same. The stress distribution in multi-scale model isn’t same with the normal model, where less stress concentration appears in the computer simulation and the result is better for the surgical recover.

Abstract: Lamb wave has important application value in material nondestructive testing. It is a kind of ultrasonic guided wave propagating in thin plate material. It has the dispersion characteristic, which greatly limits its wide application in material evaluation. After continuous wavelet transformation, we extract the feature of ridge of Lamb wave signals by adopting crazy climber algorithm. Experimental results show that Lamb wave after transmission of a certain distance has the characteristics like asymptotic signal. The ridge can reflect the dispersion characteristic of Lamb wave.

Abstract: In this paper we discuss the fundamental principle of defect analysis, introduce the basic framework of Orthogonal Defect Classification（ODC）, and summarize the principle and features of defect analysis based on ODC. Using software defect metric, defect baseline and inference rules to do software process analysis, we propose a novel defect analysis model based on ODC. Combined with practical projects, the principle of this model is discussed in details, and this model can improve the objectivity and effectiveness of defect analysis, which is favorable for the automated defect analysis.

Abstract: In general terms, the aim of "System Identification" is to determine the dynamic characteristics of mechanical systems. These characteristics include both frequency characteristics (frequencies, mode shapes, and damping ratios) and the system's characteristic matrices (the matrices of mass, viscous damping, stiffness, Coulomb damping or coefficients of friction, and the Duffing stiffness). In such fields as "Damage Detection" in structures, identification of the system's characteristic matrices is of the same importance as the identification of the frequency characteristics, or even more so, by identifying these matrices, the intended goals in Damage Detection can be achieved. In line with such identification, a new algorithm for the system identification of shear structures is presented in the paper. Taking into account the fundamental and significant effect of noise attenuation in boosting the levels of precision and the correctness of system identification, this method helps to achieve noise attenuation by trimming noisy records in the frequency domain, in parallel with the identification of the structural system. The efficiency and precision of the method have been examined through the application of a "closed loop solution" to a five storey model of shear structure.

Abstract: For the purpose of power system transient signal analysis, recognition and classification respectively ,this paper focuses on the study of electric power transient signal acquisition, signal preprocessing method and transient signal feature extraction .Based on the wavelet theory and some simulation experiments, the process of transient signal analysis is studied. And it makes a primary development of electric power transient signal analysis automatic simulation system by the simulation software. In this research, the wavelet denoising method is used and to extract the transient signal feature, which can be used in detecting transient occurrence time. Finally, the system for transient signal analysis is developed and has the wide application fields.

Abstract: Due to its high hardness and wear resistance under rolling contact, AISI E52100 steel (JIS SUJ2) is used in the manufacture of bearings and linear guides. The life estimation methods for components working under rolling contact developed up to now were designed for bearings. In this study, fatigue testing under reciprocating motion was performed and based on the microstructure, wear track investigation as well as hardness and retained austenite measurements, an evaluation method for linear guides is proposed. The results obtained from three different areas of the sample including wear tracks and non-damaged area are as follows: (1) there was little microstructure difference between the center and the end of the wear track; (2) a clear difference of the retained austenite content at the wear track and at the non-damaged area could be observed, however the percentage within different areas inside the track was similar.

Abstract: This paper focuses on the thermo-mechanical behaviors of shape memory alloy (SMA) elliptical cross-section rod subjected to torsion deformation. The stress solution in the elliptical cross-section is derived according to linear elastic mechanics. The phase transformation behaviors of the elliptical cross-section rod are described based on the phase transformation model developed by Zhou and Yoon. The phase transformation zone in the elliptical cross-section is numerically determined and discussed.

Abstract: This paper works with the CFD simulation of the process of pyrolysis of lignite particles in a downstream fluidized bed, which actually means the particles would fall down from the injection point and escape the furnace from the bottom. The particle track is solved by using the Lagrangian approach, while the flow of the inert gas (nitrogen) is dealt with by the Eulerian approach. The heat transferred from the nitrogen gas to the surface of particle is computed by means of the famous Ranz-Marshall correlation. The chemical reactions are simulated using part of the coal combustion model inserted in the commercial software used.