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Introduction PEM is the key technical material of fuel cell[1].What’s more,it’s the heart of the cell,whose  performance directly affects the performance of fuel cell operation.Aiming at the characteristics of PEM,this paper reviews the basic properties and research progress. 1 The basic properties of proton exchange membrane The proton exchange membrane(PEM) is the key part of PEM fuel cell.
Fig.1 The classification of membranes The performance of PEM can not only affect cell performance directly,but also be vitally important to reduce the cost and internal resistance of the cell, and improve the energy conversion efficiency[2].Therefore,PEM should meet the following conditions[3]:(1) high proton conductivity,(2) low electron conductivity,(3) low permeability to fuel and oxidant,(4) thermal, chemical, oxidative, and hydrolytic stability,(5) desirable mechanical properties in both the dry and hydrated states,(6) cost, and(7) capability for fabrication into membrane electrode assemblies (MEAs).
It can be seen from Table 1,these partial fluorizated membranes will be superior to the Nafion membrane in the mechanical strength, thermal stability, proton conductivity and methanol permeability,as well as the prices.However, many properties is not optimal due to materials limitations.
[3] Zh.Y.Dou:New synthesis and properties of proton exchange membrane fuel cell research(Jilin University,2011)
[5] Y.Zhao,J.Yin:Synthesis and properties of poly(ether etherketone)-block-sulfonated polybutadiene copolymers for PEM Applications.European PolymerJournal, 46(2010),p.592-601

Besides, the effectiveness of laser polishing process depends on the thermal and optical properties rather than the mechanical properties of the work material.
The increase of temperature introduces amorphous carbon to diamond layer which directly affects the mechanical, thermal and optical properties of the diamond tools.
Laser type and beam energy are the major parameters affecting the quality of the ground surfaces.
Furthermore, many other important factors, such as beam spot size and laser beam moving speed which should affect the performance characteristics, have not been considered in any detail.
Additionally, laser polishing as a thermal process induces many adverse effects to workpiece material which in turn affects the mechanical properties.

The band saw steel must present a good balance between strength, toughness and materials elasticity in the weld joint, respectively in the heat affected zone (HAZ).
Those areas are affected by the heat welding cycle that is changing the material microstructure and consequently the overall mechanical properties of the saw blade.
The strip steel dimensions are 38 x 1.14 mm, the chemical composition and mechanical properties being presented in the Table 1 [2].
Steel strip chemical composition and mechanical properties [2].
Both non-metallic inclusions or carbide precipitates at the grain boundary can negatively affect the fatigue strength of the saw blade.

The numerical simulations evaluate the influence of various factors on the production process.
The composition of AA6061was shown in the Table 1 and properties of AA6061 shown in the Table 2 and Table 3.
Table 1 Chemical Composition of AA6061 COMPONENT Wt % Al 95.8-98.6 Cr 0.04-0.35 Cu 0.15-0.4 Fe Max 0.7 Mg 0.8-1.2 Mn Max 0.15 Si 0.4-0.8 Ti Max 0.65 Zn Max 0.25 Others Max 0.15 Table 2 Physical Properties PROPERTIES VALUES Density 2.7 g/cm3 Melting point 580o Modulus of elasticity 70-80 GPa Poisson’s ratio 0.33 Table 3 Mechanical Properties of AA6061 PROPERTIES VALUES Brinell hardness 95 Vickers hardness 107 Ultimate tensile strength 260-310 MPa Tensile yield strength 276 MPa Fatigue strength 96.5 MPa Shear strength 207 MPa Shear modulus 26 GPa Sample Preparation The sample is prepared by cutting the sheet to the required dimension.
The uncertainty of experimental method in determination of the FLD was affected by many different factors, such as existence of the error in die manufacturing, implementation of deep drawing test, measurement by the profile projector and curve fitting.
Compressibility prediction of sheets steel with high strength properties.

Introduction Arch structures are widely used in civil engineering, mechanical engineering and aerospace Engineering because of its good mechanical properties, which was extensively studied by both domestic and foreign researchers [1-6].
Therefore, the circular arch considering geometrical imperfection is involved in this paper, and various factors including the geometrical imperfection and the elastic support that affecting the in-plane buckling will be studied by using the variation principle [7].
Imperfections affect the buckling in a certain extent; elastic supports play an important role in the snap-through buckling, while bifurcation buckling is not sensitive to elastic support.
The effects of the geometrical imperfections on the mechanical properties of arch structures [D].

Factors that affect syngas are the type of biomass (chemical, physical, and morphological properties) and the gasification process (type of gasifier, temperature, gasification agent, and ratio equilibrium (ER)).
The characteristics of syngas as the output of biomass gasification maybe affected by various factors which further may also affect the performance of the syngas fermentation process.
It is the goal of this paper to review the factors affecting the characteristics of syngas and the corresponding effects on the syngas fermentation performance.
These factors may affect fermentation performance and the corresponding bioethanol productivity.
Critical factors affecting the integration of biomass gasification and syngas fermentation technology.

During heat treatment of machine parts and tools, besides the usual task of ensuring a high complex of mechanical and operational properties, there is a problem of distortion of products in the process of heat treatment and the need for editing operations (which are carried out manually and require significant labor costs).
The use of special equipment makes it possible to eliminate virtually the distortion of thin-walled parts of the ring shape and to improve their mechanical properties.
During heat treatment of machine parts and tools, besides the usual task of providing a high complex of mechanical and operational properties, there arises a problem caused by the distortion of products during the heat treatment process and the need for straightening operations, which are usually carried out manually and require substantial labor costs.
The implementation of such a heat treatment scheme for disk milling cutters made it possible to virtually eliminate distortion, ensure a favorable ratio of mechanical properties, increase fatigue resistance, and reduce the labor intensity of manufacturing due to a sharp reduction in the cost of editing operations.
Schillé, Modelling phase transformations and material properties critical to the prediction of distortion during the heat treatment of steels, International Journal of Microstructure and Materials Properties, 4 (2009) 187-195

The mechanical properties of sheet materials will change with the temperature.
This will directly affect the metal formability.
Fig. 5 Effect of temperature and strain rate on the tensile strength 5 Constitutive model of ultra-high strength boron steel According to the analysis of the affecting factors on the hot flow behavior of the boron steel, constitutive model shown as equation 1 is used to model the flow behavior at elevated temperature
Lecher, Investigation of the thermo-mechanical properties of hot stamping steels, Journal of Materials Processing Technology ,177(2006), p. 452-455
Geiger, Characterization of the flow properties of the quenchable ultra high strength steel 22MnB5, CIRP Ann.Manuf.Technol., 2006,55(1), p 229-232

The stochastic nature of tool life and the large number of factors that affect the cutting process imply difficulties in accurately predicting the tool life beforehand.
Titanium alloys have been successfully applied in bioengineering and aerospace industry owing to their excellent mechanical properties and high strength-weight ratio which is 45% of steel.
However, the inherent properties of low thermal conductivity and high chemical reactivity cause poor machinability, which adversely affect tool life and cause premature tool failure.
Four cutting parameters are taken as controlled factors; 3.
In the analysis only the controlled factors are considered.

Comparing with the coatings of 1Cr18Ni9Ti, Ti and Al, the coatings of Cu have much better heat-transfer properties.
In the magnetic refrigeration machine, the property of heat exchange response to the efficiency of refrigeration.
Film adhesion is affected by the multiple factors of Van der Waals force, diffusion, mechanical lock, electrostatic attraction and chemical synthesis influence.
From the above analysis, it can be seen that the film adhesion is affected by the multiple factors of sputtering time, sputtering power density and target materials.
(2) The adhesion between Cu and Gd is very bad and they are bonded together only by mechanical link.