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With the development of information network technology, the use of cloud computing is more and more widely, cloud computing services gradually become the key technology of information network resources utilization. Articles based on cloud computing service architecture, this paper introduces the reference model, cloud computing security established cloud security content matrix, cloud application system framework is constructed. Finally, combined with the application of cloud computing security demand, put forward the application of cloud computing security strategy, for the application of cloud computing service provides a theoretical basis.

To select the optimal organic working fluid for organic Rankine cycles driven by low-temperature geothermal heat, the exergetic analysis method and PR equation of state are utilized to calculate the exergy efficiency and other main thermal performances of low-temperature geothermal heat powered organic Rankine cycles using 10 kinds of dry fluids as working fluids. The results show that: As the critical temperature of working fluid increases, the evaporation pressure, condensing pressure, output power and exergy efficiency show a decreasing trend, but the cycle thermal efficiency and the final discharge (or rejection) temperature of the geothermal fluid show an increasing trend as a whole. Moreover, the organic Rankine cycle charged with R227ea (heptafluoropropane) gets the highest power output and exergy efficiency, and the evaporation and condensation pressures are in the appropriate range, therefore, R227ea appears to be the optimal working fluid for organic Rankine cycles used in low-temperature geothermal power plant.

This paper has investigated the PT equation of state for the new environmental-friendly refrigerant R600a, and on this basis, the mathematical model of heat pump with regenerator internal heat exchanger is constructed. After systematical calculating and analyzing the cycle performance of the heat pump charged with R600a and several types under standard operating condition and variable operating conditions, the results show that the coefficient of performance charged with R600a is better than R22, thus R600a can be regarded as a promising alternative of refrigerant heat pump.

For the activated dynamics of a Brownian particle moving in a confined system with the presence of entropic barriers, this paper investigates a periodic driving and correlations between two noises. Within the two-state approximation, the explicit expressions of the mean first passage time (MFPT) and the spectral power amplification (SPA) are obtained, respectively. Based on the numerical computations, it is found that: (i) The MFPT as a function of the noise intensity exhibits a maximum with the positive correlations between two noises (λ > 0), this maximum for MFPT shows the characteristic of the entropic noise induced stability (ENIS) effect. The intensity λ of correlations between two noises can enhance the ENIS effect. (ii) The SPA as a function of the noise intensity exhibits a double-peak by tuning the noise correlation intensity λ, i.e., the existence of a double-peak behaviour is the identifying characteristic of the double entropic stochastic resonance phenomenon.