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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. 相似文献
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培养具有创新精神的高等工程人才 总被引：4，自引：0，他引：4
一、工程人才与高等工程教育从１８９５年建立北洋大学算起 ,我国高等教育和高等工程教育事业已经有１００余年的历史 ,特别是新中国成立后的５０年 ,随着国民经济的发展 ,高等教育的规模有了较大拓展 ,水平有了很大提高。我国高等学校自己培养的学生 ,不仅支撑了国民经济各个领域的技术发展 ,而且还涌现出一大批在国际工程科学研究领域具有领先地位的工程师、科学家。高等工程教育对国民经济的发展做出了巨大的贡献。１ ２１世纪需要的工程技术人才的类型（１）科学型。既具有工程专业背景 ,又具有科学技术素养和理论基础 ,以从事工程科学… 相似文献
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Aiming at reducing noise of diesel engine ,some sys-tematic reduction measures were adopted.But it is difficulttoidentify the accurate influence of different measures ,soan evaluation which combined hierarchy diagnosis and onethird octave spectra analysis… 相似文献
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The least means squares (LMS) adaptive filter algorithm was used in active suspension system. By adjusting the weight of adaptive filter, the minimum quadratic performance index was obtained. For two-degree-of-freedom vehicle suspension model, LMS adaptive controller was designed. The acceleration of the sprung mass,the dynamic tyre load between wheels and road,and the dynamic deflection between sprung mass and unsprung mass were determined as the evaluation targets of suspension performance. For LMS adaptive control suspension, compared with passive suspension, acceleration power spectral density of sprung mass acceleration under the road input model decreased 8-10 times in high frequency resonance band or low frequency resonance band. The simulation results show that LMS adaptive control is simple and remarkably effective. It further proves that the active control suspension system can improve both the riding comfort and handling safety in various operation conditions, and the method is fit for the active control of the suspension system. 相似文献
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Dynamic response of functional virtual prototyping of motorcycle under combined excitations 总被引：1，自引：0，他引：1
This paper developed 3D product models of motorcycle and engine by UGNX as well as virtual prototyping by ADAMS program with road roughness generated by MATLAB. Under the straight-line running condition, the dynamic responses of motorcycle multibody system to both road and engine excitations were compared with those to only road excitation in terms of vertical acceleration response, amplitude frequency response and power spectral density. The comparisons of simulation data showed that the response due to flat road excitation was around 20 Hz, while that to the combined excitations was in a wide frequency band, of which the major components focused on 10 Hz, 15 Hz, 35 Hz ,70 Hz, 100 Hz and even higher frequencies, reflecting the characteristics of engine excitation based on its unbalanced inertia force and torque. It is concluded that the high fidelity virtual prototyping can simulate the dynamics of motorcycle product well in investigating the vibration and ride comfort performance. 相似文献
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将配气机构软件纳入发动机的循环模拟 ,形成一套完整的综合设计软件包 .该软件包既考虑到配气系统的独立性 ,又将其作为工作过程的一部分 ,可用于综合评价并直观反映其设计优劣 .设计人员可以通过改变发动机结构、运行及凸轮的基本参数 ,在系统稳定条件下优化设计 ,大大节省设计费用和时间 .实例验证表明该软件包是厂家及设计部门优化配气系统及整机性能的有效工具 相似文献
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A bottoming cycle system based on CO2 Brayton cycle is proposed to recover the engine exhaust heat. Its performance is compared with the conventional air Brayton cycle under five typical engine conditions. The results show that CO2 Brayton cycle proves to be superior to the air Brayton cycle in terms of the system net output power, thermal efficiency and recovery efficiency. In most cases, the recovery efficiency of CO2 Brayton cycle can be higher than 9% and the system has a better performance at the engine’s high operating load. The thermal efficiency can be as large as 24.83% under 100% operating load, accordingly, the net output power of 14.86 kW is obtained. 相似文献
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In order to investigate the effects of methyl ester moiety on polycyclic aromatic hydrocarbons (PAHs) and NO x formation in biodiesel combustion, the combined models were developed based on detailed methyl butanoate (MB) oxidation model and n-butane model. Also, PAHs detailed reaction mechanism and NO x formation mechanism were added to the detailed models to form the combined models. The combined models were used to compare the combustion of n-butane and MB in a shock tube simulation to understand the effects of methyl ester moiety. The results indicated that compared with n-butane, the methyl ester moiety in MB leads to different reaction pathways, more CO and CO 2 formation and less formation of PAHs precursors such as ethylene and acetylene. In addition, a better chemical insight into the effects of methyl ester moiety on NO x formation was given, which will help to understand the combustion process of biodiesel. 相似文献
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