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The microstructure and mechanical properties of independently designed and manufactured Al-12.51Zn-2.85Mg-2.83Cu-0.18Zr-0.06Sr high strength aluminum alloy was investigated and the effect of pre-recovery on the alloy's performance was also studied. The results show that pre-recovery heat treatment has little effect on the alloy's crystal orientation, but it can consume deformation energy, reduce recrystallization driving force, inhibit recrystallization and decrease dislocation density ( the dislocation density decreased from 0.501 to 0.320×1014m-2). Moreover, pre-recovery heat treatment can dramatically increase the electrical conductivity of this alloy (the maximum electrical conductivity increased from 28.55% IACS to 34.01% IACS), however, the hardness all decreased after pre-recovery treatment, but the drop is very small. In addition, pre-recovery heat treatment can significantly improve the alloy's resistance to intergranular corrosion (the minimum intergranular corrosion depth decreased from 62.67?m to 47.43?m), however, the effect of pre-recovery heat treatment on the alloy's resistance to exfoliation corrosion is negligible.

In this paper, we introduce the notion of a (2+1)-dimensional differential equation describing three-dimensional hyperbolic spaces (3-h.s.). The (2+1)-dimensional coupled nonlinear Schrodinger equation and its sister equation, the (2+1)-dimensional coupled derivative nonlinear Schrodinger equation, are shown to describe 3-h.s. The (2+1)-dimensional generalized HF model: St = ((1/2i)[S,Sy]+2iσS)x, σx = −(1/4i) tr(SSxSy), in which SGLC(2)/GLC(1)×GLC(1), provides another example of (2+1)-dimensional differential equations describing 3-h.s. As a direct consequence, the geometric construction of an infinite number of conservation laws of such equations is illustrated. Furthermore we display a new infinite number of conservation laws of the (2+1)-dimensional nonlinear Schrodinger equation and the (2+1)-dimensional derivative nonlinear Schrodinger equation by a geometric way.

Energy conservation and environmental protection is the basic policy of China, and is an important part of ecological civilization construction. The industrial boilers in China are featured by large quantity, wide distribution, high energy consumption and heavy environmental pollution, which are key problems faced by energy conservation and environmental protection in China. Meanwhile, industrial boilers are important equipment for national economy and people's daily life, and energy conservation gets through all segments from type selection, purchase, installation and acceptance to fuel management, operation, maintenance and service. China began to implement such national mandatory standards and regulations for industrial boiler as GB24500-2009 The Minimum Allowable Values of Energy Efficiency and Energy Efficiency Grades of Industrial Boilers and TSG G002-2010 Supervision Regulation on Energy-Saving Technology for Boilers since 2009, which obviously promote the development of energy conservation of industrial boilers, but there are also some problems with the rapid development of technologies for energy conservation of industrial boilers. In this paper, the implementation of energy efficiency standards for industrial boilers in China and the significance are analyzed based on survey data, and some suggestions are proposed for the energy efficiency standards for industrial boilers.