Redispersible polymer powders of Vinyl acetate / ethylene copolymer (EVA) and Ethylene/vinyl laurate/vinyl chloride copolymer (E/VL/VC) were applied to modify decorative mortar. Results showed that EVA and E/VL/VC both smoothed the surface of mortar, decreased the leachability of Ca2+, K+, Na+ ions and increased the leachability of SO42- in the surface leaching solution. However, with redispersible EVA and E/VL/VC being the same content, E/VL/VC-modified mortar hydrated for 1d showed lower bulk density, better surface hydrophobicity, higher alkalis leachability and more severe efflorescence. Moreover, EVA and E/VL/VC both had little influence on the components of efflorescence substances on the surface of mortar.

Conjugate gradient methods are efficient to minimize differentiable objective functions in large dimension spaces. Recently, Dai and Yuan introduced a tree-parameter family of nonlinear conjugate gradient methods and show their convergence. However, line search strategies usually bring computational burden. To overcome this problem, in this paper, we study the global convergence of a special case of three-parameter family(the CD-DY family) in which the line search procedures are replaced by fixed formulae of stepsize.

In order to test the performance of metal bipolar plates more accurately and accurately, it is necessary to further study and discuss its accelerated test methods. Based on the electrochemical corrosion mechanism and the high potential state existing in the fuel cell, this paper focuses on the feasibility of accelerating the evaluation of the performance of the metal bipolar plate by changing the electrochemical parameters. As shown in the experiment, the method of " potentiostatic i-t curve versus time integrating" proposed in this paper can more accurately quantitatively analyze the long-term corrosion resistance of samples under different working conditions. The combination of high potential and accelerated solution has a significant acceleration effect. The metal corrosion can be accelerated by raising the test potential, and the surface topography changes under different corrosion stages of the metal can be observed in a short time.

In this paper, a capacitance parameters of high-precision digital measuring instrument was designed, based on the VI (virtual instruments), using LabVIEW software platform and applying current comparison measuring principle. This system possesses current comparison based on Magnetic Potential Balance Principle, PC subject, the integrated data acquisition modules and I/O control module. Magnetic potential balance has been achieved by controlling coil turns. With the function of PC, accurate test results have been gained. Because of using the closed-loop control and the successive approximation method to control relay, the system achieves equilibrium sharply. This system has been used to test the capacitance of capacitor, dielectric loss value and the inductance of reactor, which has advantages to more accuracy and stability, convenient operation, and adjusting quickly and a wide range of uses.