Research on Solar Cell with Storing Solar Energy Film

Solar cell is an effective apparatus which can transform solar energy into electrical energy. However, the main problem is the low density and discontinuity of solar energy at present. The solar cell with a layer of rare earth film can absorb incidence sunlight and enhance the energy density of solar energy. The rare earth film can absorb solar energy and bear high temperature of 300～450 ℃. Moreover, in rainy days or at night, the film radiates the solar energy it stored in 8～12 h, so that the solar cell can work continuously, which remarkably enhanced the efficiency of solar cell.

Modeling the Physical Parameters of Solenoids for MEMS Applications

The paper is devoted to study of the electrical parameters of the motion parts of the MEMS such as solenoids. The analytical background is given in order to describe the influence of the electrical field components on the forces, which are result of interaction of the electromagnetic (EM) field components with the parts of motion devices of MEMS. The given analytical formulas open the ability to calculate the self-inductance of the microsolenoids of the different kind, as well as the stored energy of such motion devices, that could be used for the modeling and optimization of parameters of running devices of MEMS such as actuators, sensors etc.

Stored energy analysis of Zn-5Al eutectic alloy in superplastic deformation

The stored energy and the energy release during SPD (superplastic deformation) of a Zn-5 Al alloy were studied. The alloy after rolling process gains more stored energy, and the as-rolled specimen can obtain maximum elongation and minimum flow stress without hot holding treatment before SPD. Experimental results show that stored energy release process is along with SPD process and is also an impetus to SPD. The as-rolled Zn-5Al alloy has 48 J/mol stored energy which was measured with DSC (differential scanning calorimeter) and conforms well to the calculated value. The as-rolled Zn-5Al alloy after SPD with an elongation of 2 500% releases 112 J/mol stored energy. Analysis shows that the strain rate is in direct ratio to the rate of stored energy release.

Numerical Investigation of the Thermal Behavior of a System with a Partition Wall Incorporating a Phase Change Material

The work deals with the thermal behavior of a conventional partition wall incorporating a phase change material(PCM).The wall separates two environments with different thermal properties.The first one is conditioned,while the adjacent space is characterized by a temperature that changes sinusoidally in time.The effect of the PCM is assessed through a comparative analysis of the cases with and without PCM.The performances are evaluated in terms of dimensionless energy stored within the wall,comfort temperature and variations of these quantities as a function of the amount of PCM and its emplacement.

A Review on Methods for Determining the Vibratory Damping Ratio

This article aims to popularize the methods for determining the vibratory damping ratio, to explain the various mathematical and physical theorems related to the establishment of literal expressions. Vibration damping is an essential parameter to reduce the dynamic responses of structures. The study aimed at its determination is necessary and essential for the safeguard of buildings and human lives during the earthquake. Among the main methods studied in this article, the free vibration attenuation method seems to be easy to implement but requires a state-of-the-art device to capture the responses. In addition to this device, the other methods require other equipment for the vibration of the system and the transformation of the responses in the frequency domain.

Continuum Constitutive Modeling for Isotropic Hyperelastic Materials

The partial differential equation for isotropic hyperelastic constitutive models has been postulated and derived from the balance between stored energy and stress work done. The partial differential equation as a function of three invariants has then been solved by Lie group methods. With geometric meanings of deformations, the general solution boils down to a particular three-term solution. The particular solution has been applied for several isotropic hyperelastic materials. For incompressible materials, vulcanized rubber containing 8% sulfur and Entec Enflex S4035A thermoplastic elastomer, three coefficients have been determined from uniaxial tension data and applied to predict the pure shear and equibiaxial tension modes. For a slightly compressible rubber material, the coefficients have also been extracted from the confined volumetric test data.

A new modeling approach for stress-strain relationship taking into account strain hardening and stored energy by compacted graphite iron evolution

Compacted graphite iron(CGI)is considered to be an ideal diesel engine material with excellent physical and mechanical properties,which meet the requirements of energy conservation and emission reduction.However,knowledge of the microstructure evolution of CGI and its impact on flow stress remains limited.In this study,a new modeling approach for the stress–strain relationship is proposed by considering the strain hardening effect and stored energy caused by the microstructure evolution of CGI.The effects of strain,strain rate,and deformation temperature on the microstructure of CGI during compression deformation are examined,including the evolution of graphite morphology and the microstructure of the pearlite matrix.The roundness and fractal dimension of graphite particles under different deformation conditions are measured.Combined with finite element simulation models,the influence of graphite particles on the flow stress of CGI is determined.The distributions of grain boundary and geometrically necessary dislocations(GNDs)density in the pearlite matrix of CGI under different strains,strain rates,and deformation temperatures are analyzed by electron backscatter diffraction technology,and the stored energy under each deformation condition is calculated.Results show that the proportion and amount of low-angle grain boundaries and the average GNDs density increase with the increase of strain and strain rate and decreased first and then increased with an increase in deformation temperature.The increase in strain and strain rate and the decrease in deformation temperature contribute to the accumulation of stored energy,which show similar variation trends to those of GNDs density.The parameters in the stress–strain relationship model are solved according to the stored energy under different deformation conditions.The consistency between the predicted results from the proposed stress–strain relationship and the experimental results shows that the evolution of stored energy can accurately predict the stress–strain relationship of CGI.

Analysis of Stored Energy in Cold-Rolled Copper Using Bulk and Microstructure-Based Techniques

Measurements of stored energy have been obtained for samples of copper cold-rolled to von Mises strains between 0.42 and 5.21 using both differential scanning calorimetry （DSC）, and based on measurements of microstructural parameters in the transmission electron microscope （TEM）. In both cases, a linear increase in stored energy with strain is found. The ratio between the two measured values varies, however, over a significant range, indicating that some caution is needed in determining the relative difference in energy associated with deformation microstructure heterogeneities in a given sample. Comparison of the stored energy with the flow stress suggests that the TEM-based measurements reflect the dislocation density content responsible for the flow stress, but that the DSC technique additionally measures other contributions to the stored energy, such as the presence of balanced internal stresses.

Evaluation of Stored Energy from Microstructure of Multi-component Nanostructured Cu

A polycrystalline Cu of 99.995% purity has been deformed by dynamic plastic deformation at liquid nitrogen temperature to a strain of 2.1 （LNT-DPD Cu）. Three distinct regions that are dominated by dislocation slip, shear banding and nanotwinning, form a multi-component nanostructure. The microstructure of each region has been quantified by transmission electron microscopy assisted by Kikuchi line analysis. Based on the structural parameters the stored energy of each region was evaluated, and the total energy can be assumed to be a linear additivity of that in each region weighted by the respective volume fraction. A microstructure based evaluation of the stored energy of multi-component nanostructure has been proposed.

Effects of Hot Deformation on the Evolution of Microstructure in Pearlitic Steel Wire Rod

The influences of hot deformation parameters on pearlite grain nucleation and growth during austenite-pearlite phase transformation in a steel wire rod have been investigated through quantitative analysis of microstructure parameters such as austenite grain size,ferrite grain size,pearlite colony size,and lamellar spacing.During hot deformation,the austenite grain size decreases due to recrystallization,providing extra nucleation sites for pearlite phase transformation,which decreases the ferrite grain size and pearlite colony size.Moreover,the stored strain energy in undercooled austenite accelerates carbon diffusion during pearlite phase transformation,which facilitates ferrite grain growth and increases pearlite colony size.Consequently,the competing influence of recrystallization and strain energy provides flexibility in adjusting ferrite grain size and colony size by hot deformation.This study highlights the critical role of hot deformation in determining the microstructure of pearlitic steel.

Microstructure change in Fe-based metallic glass and nanocrystalline alloy induced by liquid nitrogen treatment

The effects of acyclic liquid nitrogen(LN)treatment in a temperature range of-196℃to 50℃on the thermal and magnetic stability of Fe78Si9B13 and Fe73.5Si13.5B9Nb3Cu1 glassy ribbons have been studied.The intrinsic heterogeneities of the metallic glasses can be activated through cryogenic thermal cycling,making irreversible structural changes after the treatment and inducing rejuvenation to the materials.The microstructural changes of both Fe-based metallic glass(MG)and nanocrystalline alloy induced by LN treatment were investigated.The experimental results show that the LN treatment could effectively rejuvenate the Fe-Si-B MGs and change their thermomechanical and magnetic properties.Based on the partially-crystallinity and well-known magnetic constants,the increase of the energy at the order of 10m J/g and magnetic domain wall movement and rotation at the order of 5-6μm and 0.5°-0.8°are found for FINEMET-type amorphous alloy after LN treatment.It is also found that LN treatment can contribute a little stored energy to the magnetic domain wall movement and magnetic domain rotation.

Formation mechanism and evolution of surface coarse grains on a ZK60 Mg profile extruded by a porthole die

Porthole die extrusion of Mg alloys was studied by means of experimental and numerical studies. Results indicated that an inhomogeneous microstructure formed on the cross-section of the extruded profile. On the profile surface, abnormal coarse grains with an orientation of <11-20> in parallel to ED(extrusion direction) appeared. In the profile center, the welding zone was composed of fine grains with an average size of 4.19 um and an orientation of <10-10> in parallel to ED, while the matrix zone exhibited a bimodal grain structure. Disk-like, near-spherical and rod-like precipitates were observed, and the number density of those features was lower on the profile surface than that in the profile center. Then, the formation and evolution of coarse grains on the profile surface were investigated, which were found to depend on the competition between static recrystallization and grain growth. The stored deformation energy was the factor dominating the surface structure through effective regulation over nucleation of the precipitates and recrystallization. A profile with a low stored deformation energy suppressed formation of precipitates and consequently facilitated grain growth rather than recrystallization, resulting in the formation of abnormal coarse grains. Finally, the surface coarse grains contributed detrimentally to hardness, tensile properties, and wear performance of the bulk structure.

Enhanced dye degradation capability and reusability of Fe-based amorphous ribbons by surface activation

The dye degradation capability and reusability of FeSiBNbCu amorphous ribbons are largely enhanced due to the surface activation by ball milling.The time required for degrading 50%of acid orange 7 solution by the activated FeSiBNbCu amorphous ribbons is only 1/6 of that by the as-quenched ribbons,while the reusable times of the activated ribbons is 6 times larger than that of the as-quenched ribbons.The superior degradation capability and better reusability of the activated FeSiBNbCu amorphous ribbons come from not only the uneven topography of the ribbon surface induced by ball milling,but also the stored deformation energy,including the structural rejuvenation and the enlarged residual stress.The structural rejuvenation in the activated FeSiBNbCu amorphous ribbons is verified by heat relaxation analysis,and the increased residual stress is confirmed by the magnetic domain measurements on the ribbon surfaces.Besides,the environmental adaptability of the activated FeSiBNbCu amorphous ribbons is also investigated.The possible pathways for degradation of acid orange 7 using the activated ribbons,including azo bond cleavage and hydroxylation of benzene ring,are proposed.This work provides a new method to effectively improve the degradation performance of amorphous ribbons.