Energy Dissipation and Apparent Viscosity of Semi-solid Metal during Rheological Processes Part Ⅰ： Energy Dissipation

The energy dissipation caused by the viscous force has great effects on the flow property of semi-solid metal during rheological processes such as slurry preparing, delivering and cavity filling. Experimental results in this paper indicate that the viscous friction between semi-solid metal and pipe wall, the collisions among the solid particles, and the liquid flow around particles are the three main types of energy dissipation. On the basis of the hydromechanics, the energy dissipation calculation model is built. It is demonstrated that the micro-structural parameters such as effective solid fraction, particle size and shape, and flow parameters such as the mean velocity, the fluctuant velocity of particles and the relative velocity between the fluid and solid phase, affect the energy dissipation of semi-solid metal.     

Effects of Energy Dissipation on the Parametric Excitation of a Coupled Qubit–Cavity System

We consider a parametrically driven system of a qubit coupled to a cavity taking into account different channels of energy dissipation. We focus on the periodic modulation of a single parameter of this hybrid system, which is the coupling constant between the two subsystems. Such a modulation is possible within the superconducting realization of qubit–cavity coupled systems, characterized by an outstanding degree of tunability and flexibility. Our major result is that energy dissipation in the cavity can enhance population of the excited state of the qubit in the steady state, while energy dissipation in the qubit subsystem can enhance the number of photons generated from vacuum. We find optimal parameters for the realization of such dissipation-induced amplification of quantum effects. Our results might be of importance for the full control of quantum states of coupled systems as well as for the storage and engineering of quantum states.     

Energy Dissipation and Apparent Viscosity of Semi-solid Metal during Rheological Processes Part Ⅱ: Apparent Viscosity

This study investigated the rheological properties of semi-solid metal. An analytical model of apparent viscosity was built up based on analysis of energy dissipation during rheological processes such as slurry preparing,delivering and model filling. The rheological properties of SSM (semi-solid metal) slurry was described by an analytical model in terms of microstructural parameters, which consist of effective solid fraction, particle size and shape, and flow parameters such as mean velocity, fluctuant velocity and relative velocity between liquid and solid phase. The model was verified in the experiment of A356 alloys with a coaxial double-bucket rheometer. And the maximum relative error between the theoretical value and measured one is less than 10%.The results of experiment and theoretical calculation also indicate that the microstructural parameters and flow parameters are two major factors that affect the apparent viscosity of semi-solid alloys, and fluctuant velocity and relative velocity between liquid and solid phase are the key factors to distinguish between steady and transient rheological properties.     

Energy Dissipation and Apparent Viscosity of Semi-solid Metal during Rheological Processes Part Ⅱ： Apparent Viscosity

This study investigated the rheological properties of semi-solid metal. An analytical model of apparent viscosity was built up based on analysis of energy dissipation during rheological processes such as slurry preparing, delivering and model filling. The rheological properties of SSM （semi-solid metal） slurry was described by an analytical model in terms of microstructural parameters, which consist of effective solid fraction, particle size and shape, and flow parameters such as mean velocity, fluctuant velocity and relative velocity between liquid and solid phase. The model was verified in the experiment of A356 alloys with a coaxial double-bucket rheometer. And the maximum relative error between the theoretical value and measured one is less than 20%. The results of experiment and theoretical calculation also indicate that the microstructural parameters and flow parameters are two major factors that affect the apparent viscosity of semi-solid alloys, and fluctuant velocity and relative velocity between liquid and solid phase are the key factors to distinguish between steady and transient rheological properties.     

Dissipation of Solitary Waves in Aluminum with Grain Boundary

The behaviour of passing solitary waves through the region of grain boundary has been investigated on the basis of the molecular dynamics method. It has been shown that solitary waves initiated by compression and shear loading have a different interaction with the grain boundary region. The possibilities of using solitary waves for nondestructive testing of materials, in particular, for testing the quality of coatings, for testing of accumulation of microdamages, etc. have been noted.     

Discussion of Dissipation Structure in a Directionally Solidified Alloy

The dissipation theory was introduced into the solidification area to describe the inherent laws of solidification from a new viewpoint. Discussion demonstrates that the solid / liquid interface in a directionally solidified alloy belongs to a kind of dissipation structure     

Dissipation in a Gold Nanomechanical Resonator at Low Temperatures

We present results from a study of the dissipation in nanomechanical gold resonators. We fabricated a nanomechanical resonator consisting of a gold wire of width 300 nm, thickness 80 nm and length 7.5 μm by etching away the underlying GaAs substrate. At low temperatures the resonator had a fundamental frequency of about 7.95 MHz, in part due to tension arising from differential thermal contraction between the gold beam and the underlying semiconductor substrate. The dissipation in the resonator was measured using the magnetomotive method over the temperature range 1 K to 10 mK. We find that the Q-factor of the resonator increases by more than a factor of four between 600 mK and 10 mK. The dissipation follows a weak power law dependence on temperature, ∝ T ^0.5, from approximately 30 mK to 600 mK.     

Alloy Model for the Stacking Fault Energy

An accurate and simple model of stacking fault energy for alloys (solid solutions) has beendeveloped based on the embedded-atom method. The calculated value of stacking fault energy35 mJ/m2 for 304 austenitic stainless steel, is in a good agreement with the experimental one,30 mJ/m2. In the present model we find that the Hirth's empirical relationship is also suitablefor alloy.     

Low Energy Dislocation Structure in Deformed Metals

In this paper,the dislocation distribution struc-ture in deformed metal is discussed.The flow stressof material for the heterogeneous dislocation distri-bution which tends to the flow stress for the homo-geneous dislocation distribution in the limiting caseis derived.The causes and the effects of the longrange internal stresses are discussed.The totaldeformation energy of material system is obtainedand the trend of evolution of dislocation distribu-tion in deformed metals is discussed simultaneously.No micromechanisms of dislocations are involvedin the discussion,therefore the theory developed inthis paper is universal.     

VELUX携手Energy Micro打造新款触摸屏遥控器

基于ARMCortex-M3的EFM32 Giant Gecko MCU使VELUX的手持式遥控在睡眠状态时低功耗电容式传感器界面的功耗为仅为1．2μA挪威，奥斯陆2013年1月15日-节能微控器和无线射频供应商Energy Micro宣布：世界屋顶窗领域的领导者VELUS（威卢克斯）公司的最新款电动窗遥控选用其EFM32 Giant Gecko微控制器。     

Framework for the China Energy Efficiency Label System

On August 13, 2003, the National Development and Reform Commission and General Administration of Quality Supervision, Inspection and Quarantine of P.R.C (AQSIQ) jointly formulated and issued The Regulations for Energy Efficiency La-     

Perspectives of China’s Wind Energy Development

Wind energy is a kind of clean renewable energy, which is also relatively mature in technology, with large-scale development conditions and prospect for the commercialization. Wind energy’s development and utilization is an important measure to increase energy supply, adjust energy structure, ensure energy security, protect the ecological environment, reduce greenhouse gas emission and build a harmonious society. Wind energy is a kind of clean renewable energy, which is also relatively mature in technology, with large-scale development conditions and prospect for the commercialization. The development of wind energy is a systematic project, involving policy, law, technology, economy, society, environment, education and other aspects. The relationship among all the aspects should be well treated and coordinated. This paper has discussed the following relationships which should be well coordinated: relationship between wind resources and wind energy development, relationship between the wind turbine generator system and the components, relationship between wind energy technology and wind energy industry, relationship between off-grid wind power and grid-connected wind power, relationship between wind farm and the power grid, relationship between onshore wind power and offshore wind power, relationship between wind energy and other energies, relationship between technology introduction and self-innovation, relationship among foreign-funded, joint ventured and domestic-funded enterprises and relationship between the government guidance and the market regulation, as well as giving out some suggestions.     

Specific Heat and Interface Energy of Nanostructured ZrAlNiCuCo Alloy

The specific heat of the nanostructured crystals, the glass, the liquid and the crystals for a ZrAINiCuCo alloy has been measured by using the differential scanning calorimeter. The specific heat value and its temperature coefficient of the nanostructured crystals are larger than that of the relaxed glass and of the crystals. Through measuring crystallization enthalpies and specific heat of the alloy in different states, the enthalpy difFerences among the crystals, the liquid and the nanostructured crystals are calculated and the intedece energies of nanostructured crystals are estimated. The stability and the grain size limit of the nanostructured crystals are discussed.     

Nanotechnology for Energy Harvesting： from Nanogenerators to Nanopiezotronics

2008年10月23—27日，“2008第七届中国纳米科技（武汉）研讨会”在湖北武汉隆重召开。Prof．Robert Snyder（Georgia Institute of Technology），Prof．Ward Plummer（Oak Ridge National Laboratory and University of Tennessee），Prof．M．P．Pileni（University of Marieand Cuffe，France），Prof．ZhongLin．Wang（Georgia Institute of Technology，USA）和薛其坤院士（Tsinghua University）、赵东元院士（Fudan University）、李亚栋教授（Tsinghua University）等出席大会并做特邀主题报告。本期介绍欧洲科学院院士王中林博士的报告摘要：     

Talking about Metrology and Energy On World Metrology Day

The them e of this year's W orld M etrology D ay is “M etrology and Energy”. The energy problem is an im -portant issue for the w hole w orld and has received great attention in China since China is both a big energy-con-sum ing country and a country severely short of energy. U nder the energy and environm ental pressure, China w ill take m easures in the follow ing four respects in or-der to solve the problem of energy shortage: 1. China w ill stick to the self-reliance principle for ene…     

Application of Electron Energy Loss Spectroscopy and Energy Filtering Transmission Electron Microscopy for Microchemical Studies in 2.25Cr-1Mo Steel

Electron enregy loss spectroscopy (EELS) and energy filtering transmission electron microscopy (EFTEM) investigation on 2.25Cr-lMo steel was carried out to understand the nature of evolution of secondary carbides. The filtered images obtained from two different ageing treatments indicate that the steel evolves to a more stable carbide namely M23C6 in comparison to M2C. Microchemical information was generated from EELS spectra. Suitable choice for estimating the microchemical state was discussed. To evaluate the behaviour of ageing an elemental ratio of Fe to Cr is employed.     

About Nonlinear Mechanism of Energy Transformation at Ion Implantation

Thedetailedstudy0fpeculiarities0fthen0nlin-earmaterialresp0nse,takingplaceunderhighenergyloading,isnecessaryforunderstandingphysicalna-tureoftheseprocesses.Thispr0blemrepresentsasignificantinterestbothinthescientificandintheappliedaspectsl1l2].Itisconnectedwiththenewma-terialdevelopmentforw0rkinginextremeconditions(highpressureandtemperature,shockl0ading,radi-ationprocessingetc.).Oneofthemethodswhichhasbeenusedprettylongagoandsuccessfullyforstudyingn0nlinearmaterialresponseonthemicroleveIisthe…     

Standard Gibbs Free Energy of Formation of Zirconium Oxysulphides

1.IntroductionThe chemistry of rare earthoxysulphides is well known [1-5] and theyhave extensive technological applications,but the d-transition metal oxysulphides wasnot known until recently [6-9].Therefore,itis necessary to study the thermodynamicproperties of these compounds.     

Triboelectric–Electromagnetic Hybrid Generator for Harvesting Blue Energy

Nano-Micro Letters - The synergistic effect of conventional flame-retardant elements and graphene has received extensive attention in the development of a new class of flame retardants. Compared to...     

Polymer-Based Batteries—Flexible and Thin Energy Storage Systems

Batteries have become an integral part of everyday life—from small coin cells to batteries for mobile phones, as well as batteries for electric vehicles and an increasing number of stationary energy storage applications. There is a large variety of standardized battery sizes (e.g., the familiar AA-battery or AAA-battery). Interestingly, all these battery systems are based on a huge number of different cell chemistries depending on the application and the corresponding requirements. There is not one single battery type fulfilling all demands for all imaginable applications. One battery class that has been gaining significant interest in recent years is polymer-based batteries. These batteries utilize organic materials as the active parts within the electrodes without utilizing metals (and their compounds) as the redox-active materials. Such polymer-based batteries feature a number of interesting properties, like high power densities and flexible batteries fabrication, among many more.