Relationship between tensile strength and porosity for high porosity metals

An analysis model has been established according to the structure feature of high porosity metals, and the mathematical relationship between the tensile strength and porosity for this material has been derived from the model. Moreover, the corresponding theoretical formula has been proved good to reflect the variation law of tensile strength with porosity for high porosity metals by the example experiment on nickel foam.     

Laguerre simulation and visualization for microstructure of metal materials

Simulation method was designed to divide Laguerre diagram for right circle group with different weight; out-of-core incremental algorithm for Laguerre diagram was constructed; simulation program development and visualization was done and simulation was realized in user-specified arbitrary area for simulation of metal materials microstructure, which facilitated the practical application and secondary development of Laguerre diagram in the field of material science engineering. Finally, the utilization of a developed software package exemplified the simulation application of microstructure about metal materials and proved its validity.     

Interaction between subinterface cracks and interface in metal/piezoelectric ceramic bimaterials

A class of problems concerning subinterface cracks interacting with the interface in metal/ piezoelectric ceramic bimaterials are studied. The interaction problem is reduced to a system of integral equations with the aid of the pseudo-traction-electric-displacement method. The equations are solved numerically, and the stress intensity factor, the electric displacement intensity factor and the mechanical strain energy release rate are evaluated. Numerical results of a Cu/PZT-4 bimaterial are given and shown in figures, in which three kinds of remote loading conditions are considered to make comparisons . It is found that the electric loading at infinity plays a quite important role in the present interaction problem. In addition, a conservation law of the first component of the Jk-integral vector is found, which does lead to a consistency check to confirm the effectiveness of the PTEDM as well as the numerical results derived in this paper.     

Relationship between Ballistic Coefficient and Static Mechanical Properties for Armor Materials

The relationship between the ballistic coefficient and the static mechanical properties of armor materials was studied. The results show that the ballistic coefficient is determined by the strength, hardness and the toughness of materials. According tO the Martel rule, the equation of the relationship between ballistic coefficient and static mechanical properties satisfies the following formula: Ws = F(1+NKICP)HT. From the mixture law of composite, the prerequisite, for which ballistic coefficient has maximum to reinforcement volume fraction, is obtained by the following equation:     

Comparison between sequential and single extraction procedures for metal speciation in fresh and dried Sedum Plumbizincicola

Sequential and single extraction procedures were applied to both fresh and dried Sedum Plumbizincicola leaves and stems.The extractants, different from those of soil, sediment or sewage sludge metal fractions, were water, 80%(v/v) ethanol, 1 mol/L Na Cl,2% HAc and 0.6 mol/L HCl. Zn, Cd and Cu in the extracts and samples were measured by flame atomic adsorption spectrometry. In sequential extraction procedures, water soluble form and ethanol soluble form are the main fractions for Zn, while water soluble form and Na Cl soluble form for Cd, and comparatively uniform distribution for Cu with the residue form most and HCl soluble form second. Single extraction procedures are used to compare the extraction efficiencies of the five reagents to screen appropriate extractants and operating conditions for liquid extraction to deal with large amount of harvested metal-contained biomass, which will pose a threat to the environment if treated improperly. The sequences of extraction efficiencies are HCl>Na Cl≈HAc>Water≈Ethanol for Zn and HCl≈Na Cl≈HAc>Water>Ethanol for Cd. As for Cu, all the five extractants cannot effectively extract Cu, but HCl achieves a higher efficiency(>70% in fresh samples, and 45%-60% in dried samples). Besides, extraction efficiencies for most extractants in fresh samples are higher than those in dried samples, and extraction efficiencies of stems and leaves for the five extractants are close. The two extraction procedures can obtain high degree of accuracy with the relative standard deviation(RSD)lower than 10%, and metal recoveries are controlled between 80%-120% with most of 90%-110%.     

磁记忆与小波变换相结合的井下套管应力集中早期诊断方法

利用铁磁材料的磁记忆性,研制出了井下在役套管检测系统。该检测系统可根据在役套管的应力集中区所产生的磁记忆信号快速、准确地判断套管的应力集中区状况。基于小波系数的“Teager”能量算子,增强了分解后的磁记忆信号能量;从小波变换的信号奇异性检测理论出发,把多尺度变换结果观测与俄罗斯专利技术(梯度)相结合,能准确判断异常应力集中区,实现了信号自适应小波消噪,提取了磁记忆的特征量梯度。实验结果证实了该方法的有效性和可行性。     

Friction-reducing and antiwear behavior of metal halide-stabilized linear phosphazene derivatives as lubricants for a steel-on-steel contact

The linear chlorophosphazene oligomers family has been extensively investigated not only as a kind of lubricating additive but also as a kind of heat transfer medium, dielec-tric fluid, high-temperature lubricant, and working fluid usable within a wide range of temperature between the freezing and boiling points[1?4]. Since the 1960s, the U.S. Air Force Materials Laboratory sponsored the development of linear chlorophosphazeneoligomers for high temperature fluids. However, highly polymerized…     

Relationship between Low Temperature Toughness and Microstructure in Low Activation Fe-Cr-Mn (W, V) Steel for Fusion Reactors

Fe-Cr-Mnalloys,asthefirstwallmaterialsoffusionreactors,haVemadadVantages(lowcost,goodswellingresistance,lowradioactivity,etc.)comparingwithFe-Cr-NisyStems[l--31.Intherecentyears,manyresearchershavebeengreatlyinterestingintheresearchanddevelopmentoncl...