Chaos in a Damped Power System

The analytical investigation of a damped power system has been made based on Holmes and Marsden's theorems. The condition for the occurrence of chaotic motions in the system is that the damping factor has to possess negative values. The numerical simulation results concur very well with theoretical predictions.

One-pot In-situ Synthesis of Sn/Carbon-fibers Nanocomposite by Chemical Vapor Deposition and Its Li-storage Properties

Sn/carbon-fibers（CFs） nanocomposite has been prepared by chemical vapor deposition with in-situ catalytic growth of CFs.The nanocomposite has been characterized by X-ray diffraction（XRD）,field emission scanning electron microscopy（FE-SEM）,transmission electron microscopy（TEM） and Raman spectrum.The electrochemical performance of the nanocomposite has been investigated by galvanostatic cycling and cyclic voltammetry（CV）.It has been found that a three-dimensional conductive network forms by the interconnected CFs,which offers conductive channels for the Sn nanoparticles.The nanocomposite gives a first charge capacity of 385 mAh.g-1 and exhibits an improved cycling stability than bare Sn.

Dynamic Impact of High-Density Aluminum Foam

High-density aluminum foam can provide higher stiffness and absorb more energy during the impact Obtaining the constitutive law of such foam requires tri-axial tests with very high pressure,where difficulty may arise because the hydrostatic pressure can reach more than 30 MPa.In this paper,instead of using tri-axial tests,we proposed three easier tests-tension,compression and shear to obtain the parameters of constitutive model(the Deshpande-Fleck model).To verify the constitutive model both statically and dynamically,we carried out addi-tional triaxial tests and direct impact tests,respectively.Based on the derived model,we performed finite element simulation to study the impact response of the present foam.By dimensional analysis,we proposed an empirical equation for a non-dimensional impact time the impact time divided by the time required for plastic wave travelling from the impact surface to the bottom surface,to det ermine the deformation charac teristic of the aluminum foam after impact.For the case with t_(d)≤1,the deformation tends to exhibit a shock-type characteristic,while for the case with t_(d)>5,the deformation tends to exhibit an upsetting-type characteristic.

Service-oriented infrastructure for flood mapping using optical and SAR satellite data

In this paper,we present the service-oriented infrastructure within the Wide Area Grid project that was carried out within the Working Group on Information Systems and Services of the Committee on Earth Observation Satellites.The developed infrastructure integrates services and computational resources of several regional and national Grid systems:Ukrainian Academician Grid(with satellite data processing Grid segment,UASpaceGrid)and Grid system at the Center on Earth Observation and Digital Earth of Chinese Academy of Sciences.The study focuses on integrating geo-information services on flood mapping provided by Ukrainian and Chinese entities to benefit from information acquired from multiple sources.We also describe services for workflow automation and management in Grid environment and provide an example of workflow automation for generating flood maps from optical and synthetic-aperture radar satellite imagery.We also discuss issues of enabling trust for the infrastructure using certificates and reputation-based model.Applications of utilizing the developed infrastructure for operational flood mapping in Ukraine and China are given as well.