Applied Mechanics and Materials Vols. 55-57

Abstract: Twin-screw extruder is the main equipment for puffed food processing. Corn powder as the main raw material, barrel temperature, screw speed and feed rate of the extruder as the independent variables, specific volume of the extrusion product as the objective function, experiment has been carried out base on factorial design method. How the independent variables influence the objective function has been analyzed. Values of the operating parameters to get optimal specific volume has been gained.

Abstract: When a digital watermark is directly embedded into low frequency part of audio, sensitive noises maybe occur. In the paper, a method of audio digital watermark based on quantization index modulation is proposed to solve the problem. At first, audio signal is divided to fragment by audio mask effect. Then low frequency part of discrete wavelet transform (DWT) is extracted. Scrambling watermark is embedded into the low frequency part by quantization index modulation (QIM). The experiment results show that the presented method has a good capacity to fight many attacks.

Abstract: Camellia anthrax disease is the main disease in producing areas of China. It occurred widespread, caused fruit and flowers dropped seriously, resulting in huge economic losses. In this paper, we separated pathogen with organizational separation method from the diseased leaves and fruit which were infected by Camellia anthrax. Then we proved, by Koch rule, it was pathogen which caused Camellia anthrax disease. According to their morphological characteristics, we identified that it was Colletotrichum gloeosporioides. From the Camellia healthy leaves, we isolated totally 125 strains endophytic fungi. Through the primary screening, 13 strains were detected had inhibited on Colletotrichum gloeosporioides. After the secondary screening, we obtained three strong antagonistic fungi, numbered Cd7, Sy3, Hy19, the inhibition rates separately were 60.3%, 59.7%, 57.8% on the PAD flat.

Abstract: Strained Si_1-xGe_x technology has been widely adopted to enhance hole mobility. One of the most important physical parameters is density of state near the top of valence band in strained Si_1-xGe_x materials. In this paper, we first obtained the hole effective mass along arbitrarily k wavevector directions, the hole isotropic effective masses and density of state effective mass of hole in strained Si_1-xGe_x/(001)Si with the framework of K.P theory. And then, model of density of state near the top of valence band in strained Si_1-xGe_x/(001)Si materials was established, which can provide valuable references to the understanding on its material physics and theoretical basis on the other important physical parameters.

Abstract: The formation and development of adiabatic shear localization in serrated chips have great significance to study of mechanism of high speed cutting. This paper investigates the theory prediction and experimental verification of the critical cutting speed of adiabatic shear localization, distribution of adiabatic shear band in serrated chip and the geometry of adiabatic shear band during high speed cutting of hardened steel. The results indicated that the theoretical prediction of critical cutting speed is consistent with the experimental results.With the increase of cutting speed, the width and spacing of adiabatic shear bands in the serrated chips decrease linearly. There are two types of adiabatic shear bands during the formation and development of adiabatic shear localization, i.e. the deformation shear band and the transformed shear band.

Abstract: The type selection for agricultural machinery generally depends on the selector’s experiences at the present time. It exist some subjectivity and one-sidedness unavoidably. On the basis of the characteristics of complexity and the uncertainty of optimal selection for agricultural machinery, grey relational analysis model in agricultural machinery multi-type selection application has been put forward in this paper. The index system of influencing agricultural machinery type selection is determined. Application model and procedures of the grey relational analysis method are introduced. According to the degree how close it is with the ideal dot, the optimal type is easy to be selected out. Through the optimization analysis type selection for the agricultural transporter, it is proved that the optimal type selection for agricultural machinery based on grey relational analysis has the strong recognition judgment ability. It is convenient, quantitative, and strict. It provided a new method and a possible new way for evaluation of agricultural machinery type selecting．

Abstract: In this paper, vibration characteristics of super-heavy vibrating shaker were simulated by using MATLAB based on the developed analytical models. The important stiffness test experiment of elastic component-shaker rubber spring in compression, shear stiffness and experimental verification of mechanical models were made. Results show that the test data was consistent with simulation data, which verified the correctness of design and analysis.

Abstract: A novel approach is proposed to automatically extract data records from detail pages using hierarchical clustering techniques. The approach uses the information of the listing pages to identify the content blocks in detail pages, which narrows the scopes of Web data extraction. Meanwhile, it also makes full use of the structure and content features to cluster content feature vectors. Finally, it aligns data elements of multiple details pages to extract the data records. Experiment results on test beds of real web pages show that the approach can achieve high extraction accuracy and outperforms the existing techniques substantially.

Abstract: The problem of four-linkage guide mechanism synthesis is transformed into nonlinear equations to be found, Newton iterative method is an important technique to one dimensional and multidimensional variables and iterative process exhibits sensitive dependence on initial guess points. For the first time, the mechanical chaos methods of mechanism synthesis and all solutions of the nonlinear questions of mechanism synthesis were found by utilizing chaos sequences of chaos motions of mechanical system to obtain locate initial points. As an example the problem of function generation for planar four-linkage guide mechanism was considered. This makes that multi-projects selecting could be possible. This method is adaptive to planar multi-linkage and spatial mechanism. This provides a new simple realization method for mechanics design.