A statistical approach to evaluate the subjective perception of the annoyance caused by the vehicle noise was presented in this paper. After recording the noises of Sanfeng, Huali and Xiali at speeds of 30, 40, 50, 60...A statistical approach to evaluate the subjective perception of the annoyance caused by the vehicle noise was presented in this paper. After recording the noises of Sanfeng, Huali and Xiali at speeds of 30, 40, 50, 60, 70 and 80 km/h respectively, the annoyance of the vehicle noises was evaluated in the testing room using paired comparison method, and the sound quality metrics and subjective annoyance were then distilled. Loudness, sharpness, roughness, periodicity and impulsiveness were selected for each of the vehicle noises. By correlation analysis method, it can be found that loudness has a higher correlation （0.91） with annoyance than other parameters. Meanwhile, sharpness, periodicity, roughness and impulsiveness have correlation with subjective perception with correlation coefficients being 0.84, -0.82, 0.62 and 0.87, respectively. The result of multiple regression analysis shows that calculated annoyance obtained by the regression equation can explain the perceptual annoyance and the regressed evaluation model is feasible to evaluate the sound quality of vehicle.展开更多
This paper provides a comprehensive analysis on cooling tower fouling data taken from seven 15.54 mm I.D. helically ribbed, copper tubes and a plain tube at Re = 16000. There are two key processes during fouling forma...This paper provides a comprehensive analysis on cooling tower fouling data taken from seven 15.54 mm I.D. helically ribbed, copper tubes and a plain tube at Re = 16000. There are two key processes during fouling formation： fouling deposition and fouling removal, which can be determined by mass transfer and fluid friction respectively. The mass transfer coefficient can be calculated through three analogies： Prandtl analogy, VonKarman analogy, and Chilton-Colburn analogy. Based on our analyses, Von-Karman analogy is the optimized analogy, which can well predict the formation of cooling tower fouling. Series of semi-theoretical fouling correlations as a function of the product of area indexes and efficiency indexes were developed, which can be applicable to different internally ribbed geometries. The correlations can be directly used to assess the fouling ootential of enhanced tubes in actual coolinu tower water situations.展开更多
Nitrogenous fertilizers of prolonged action were developed on the basis of carbamide （urea）. Technological schemes and parameters are offered to obtain restructured carbamide. Possible versions of degradation of dif...Nitrogenous fertilizers of prolonged action were developed on the basis of carbamide （urea）. Technological schemes and parameters are offered to obtain restructured carbamide. Possible versions of degradation of different structure prolonged action fertilizers are considered. It was shown that the most favorable conditions for degradation of polymer molecules are created when molar ratio of the initial carbamide and aldehyde is within 1：1-1.3, correspondingly. At such terms the linear structure molecules with rare cross-links are formed. Such structure is more accessible for penetration of ureasive ferments into polymer molecules.展开更多
基金Supported by Province and University Cooperation Fund of Yunnan Province (No. 2003HBBAA02A049).
文摘A statistical approach to evaluate the subjective perception of the annoyance caused by the vehicle noise was presented in this paper. After recording the noises of Sanfeng, Huali and Xiali at speeds of 30, 40, 50, 60, 70 and 80 km/h respectively, the annoyance of the vehicle noises was evaluated in the testing room using paired comparison method, and the sound quality metrics and subjective annoyance were then distilled. Loudness, sharpness, roughness, periodicity and impulsiveness were selected for each of the vehicle noises. By correlation analysis method, it can be found that loudness has a higher correlation （0.91） with annoyance than other parameters. Meanwhile, sharpness, periodicity, roughness and impulsiveness have correlation with subjective perception with correlation coefficients being 0.84, -0.82, 0.62 and 0.87, respectively. The result of multiple regression analysis shows that calculated annoyance obtained by the regression equation can explain the perceptual annoyance and the regressed evaluation model is feasible to evaluate the sound quality of vehicle.
基金Supported by the National Natural Science Foundation of China(51210011,51276091)the Research Award Fund for Outstanding Young Scientists in Shandong Province(BS2012CL014)the Natural Science Foundation of Zhejiang Province,China(Z13E060001)
文摘This paper provides a comprehensive analysis on cooling tower fouling data taken from seven 15.54 mm I.D. helically ribbed, copper tubes and a plain tube at Re = 16000. There are two key processes during fouling formation： fouling deposition and fouling removal, which can be determined by mass transfer and fluid friction respectively. The mass transfer coefficient can be calculated through three analogies： Prandtl analogy, VonKarman analogy, and Chilton-Colburn analogy. Based on our analyses, Von-Karman analogy is the optimized analogy, which can well predict the formation of cooling tower fouling. Series of semi-theoretical fouling correlations as a function of the product of area indexes and efficiency indexes were developed, which can be applicable to different internally ribbed geometries. The correlations can be directly used to assess the fouling ootential of enhanced tubes in actual coolinu tower water situations.
文摘Nitrogenous fertilizers of prolonged action were developed on the basis of carbamide （urea）. Technological schemes and parameters are offered to obtain restructured carbamide. Possible versions of degradation of different structure prolonged action fertilizers are considered. It was shown that the most favorable conditions for degradation of polymer molecules are created when molar ratio of the initial carbamide and aldehyde is within 1：1-1.3, correspondingly. At such terms the linear structure molecules with rare cross-links are formed. Such structure is more accessible for penetration of ureasive ferments into polymer molecules.
