TWO DIMENSIONAL PROPERTIES OF REVERSED DUCKWEED AMPHIPHILIC POLYMER

The surface pressure-Area isotherms of Reversed Duckweed amphiphili polymer were examined in view of their chemical structure and two- dimentional properties of polymer monolayer were studied.

Effect of Dimension Parameters on the Torsion Property of A C/SiC Pipe

Through finite element numerical simulation and based on laminated plate theory, the effect of dimension on the torsion properties of uniform C/SiC composites pipe was studied to provide a theoretical guidance for preparing the C/SiC pipe with different dimensions. The results show that, with increasing length of pipe, the anti-torsion section coefficient of pipe increases whereas the torsion angle per unit length decreases. Increasing the length can improve the torsion property. Anti-torsion section coefficient rises with increasing internal radius, while the torsion angle per unit length decreases to a constant. With increasing thickness, the anti-torsion section coefficient increases whereas the amplitude decreases gradually, and the torsion angle per unit length is a constant. Increment of internal radius and thickness improves the torsion property finitely.

A MULTISCALE MECHANICAL MODEL FOR MATERIALS BASED ON VIRTUAL INTERNAL BOND THEORY

Only two macroscopic parameters are needed to describe the mechanical properties of linear elastic solids, i.e. the Poisson＇s ratio and Young＇s modulus. Correspondingly, there should be two microscopic parameters to determine the mechanical properties of material if the macroscopic mechanical properties of linear elastic solids are derived from the microscopic level. Enlightened by this idea, a multiscale mechanical model for material, the virtual multi-dimensional internal bonds （VMIB） model, is proposed by incorporating a shear bond into the virtual internal bond （VIB） model. By this modification, the VMIB model associates the macro mechanical properties of material with the microscopic mechanical properties of discrete structure and the corresponding relationship between micro and macro parameters is derived. The tensor quality of the energy density function, which contains coordinate vector, is mathematically proved. From the point of view of VMIB, the macroscopic nonlinear behaviors of material could be attributed to the evolution of virtual bond distribution density induced by the imposed deformation. With this theoretical hypothesis, as an application example, a uniaxial compressive failure of brittle material is simulated. Good agreement between the experimental results and the simulated ones is found.

Sure feature screening for high-dimensional dichotomous classification

The curse of high-dimensionality has emerged in the statistical fields more and more frequently.Many techniques have been developed to address this challenge for classification problems. We propose a novel feature screening procedure for dichotomous response data. This new method can be implemented as easily as t-test marginal screening approach, and the proposed procedure is free of any subexponential tail probability conditions and moment requirement and not restricted in a specific model structure. We prove that our method possesses the sure screening property and also illustrate the effect of screening by Monte Carlo simulation and apply it to a real data example.

Processing of a Novel Zn Alloy Micro-Tube for Biodegradable Vascular Stent Application

In recent years, zinc based alloys as a new biodegradable metal material aroused intensive interests. However, the processing of Zn alloys micro-tubes （named slender-diameter and thin-walled tubes） is very difficult due to their HCP crystal structure and unfavorable mechanical properties. This study aimed to develop a novel technique to produce micro-tube of Zn alloy with good performance for biodegrad- able vascular stent application. In the present work, a processing method that combined drilling, cold rolling and optimized drawing was proposed to produce the novel Zn-5Mg-1Fe （wt%） alloy micro- tubes. The micro-tube with outer diameter of 2.5 mm and thickness of 130 μm was fabricated by this method and its dimension errors are within 10 μm. The micro-tube exhibits a fine and homogeneous microstructure, and the ultimate tensile strength and ductility are more than 220 MPa and 20% respectively. In addition, the micro-tube and stents of Zn alloy exhibit superior in vitro corrosion and expansion performance. It could be concluded that the novel Zn alloy micro-tube fabricated by above method might be a promising candidate material for biodegradable stent.

Dimension Properties of Sample Paths of Self-Similar Processes

The Hansdorff dimensions of the image and the graph of random fields are given under general conditions.The results can be used to a wider class of self-similar random fields and processes,including Brownian motion,Brownian sheet,fractional Brownian motion,processes with stable or(α,β)-fractional stable components.