期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
对ISO6358-1定压法的评说与建议 被引量:8
1
作者 张士宏 徐文灿 《液压气动与密封》 2015年第6期75-80,共6页
对定压法的均方根误差分析及实测表明,使用qm/q*m=0.74±0.05一点,可以测出临界压力比b值;使用超临界流态(p2/p1<b)的一点,可以测出声速流导C值。上述测量方法相对于ISO6358-1(2013)标准中的定压法,不仅提高了b值的测量可信度,... 对定压法的均方根误差分析及实测表明,使用qm/q*m=0.74±0.05一点,可以测出临界压力比b值;使用超临界流态(p2/p1<b)的一点,可以测出声速流导C值。上述测量方法相对于ISO6358-1(2013)标准中的定压法,不仅提高了b值的测量可信度,而且可节气86%以上。ISO6358-1(2013)定压法中,五个流量特性参数(C、b、m、△pc和Kp)的定义存在模糊和不正确的地方,在测试装置的规定和测试方法上也存在着诸多问题。该文在提出并讨论上述观点的基础上,对定压法提出了改进意见。 展开更多
关键词 ISO6358-1 定压法 临界压力比 均方根误差分析
下载PDF
对ISO 6358-2等温容器放气法的评说和建议 被引量:3
2
作者 惠伟安 徐文灿 +2 位作者 张士宏 路波 李武杰 《液压气动与密封》 2016年第2期76-80,共5页
该文对ISO 6358-2(2013)等温容器放气法计算临界压力比b值的方法的可信性提出了质疑。利用等温放气法测量C,b值,有两点需要讨论,第一,测流动中的气体压力,应流动达稳定时才能正确测量。对等温放气法,测气罐内的瞬态压力随时间的变化曲... 该文对ISO 6358-2(2013)等温容器放气法计算临界压力比b值的方法的可信性提出了质疑。利用等温放气法测量C,b值,有两点需要讨论,第一,测流动中的气体压力,应流动达稳定时才能正确测量。对等温放气法,测气罐内的瞬态压力随时间的变化曲线,测出的瞬态压力与该时刻的真实压力有多大误差?第二,该偏差对确定C,b值会带来多大的影响?对C、b值的均方根误差分析表明,测量仪表的精度宜使用特级,不宜使用A级。特级测量精度计算b值的最佳的供气压力在0.2~0.5bar(g)之间,故对流通能力小的元件及有最低使用压力要求的元件,不宜使用本方法。对同一个被测阀,用各种方法测量其S值和b值,发现等温放气法测不出S值和b值,但用定压法和串接法,测出的S值和b值都非常接近。 展开更多
关键词 等温容器放气法 国际标准 流量特性 声速流导 临界压力比 有效截面积 均方根误差分析
下载PDF
对串接声速排气法的评说与建议 被引量:3
3
作者 张士宏 徐文灿 +2 位作者 惠伟安 路波 李武杰 《液压气动与密封》 2015年第11期1-4,共4页
针对串接声速排气法,对两个流量特性参数S、b值进行了均方根误差分析,表明该方法所测出的S值和b值可信度高。串接声速排气法可在最佳点测b值,且辅助元件的S值可在很宽的范围内选择,都能保证测出的被测元件的b值的正确性。通常,可以选直... 针对串接声速排气法,对两个流量特性参数S、b值进行了均方根误差分析,表明该方法所测出的S值和b值可信度高。串接声速排气法可在最佳点测b值,且辅助元件的S值可在很宽的范围内选择,都能保证测出的被测元件的b值的正确性。通常,可以选直通型快换接头作为辅助元件,该接头b值大,且连接方便。该方法的测试设备成本低,测试时耗气量很小,被测件的通径不受限制,但是不能测出口无连接的气动元件。 展开更多
关键词 串接声速排气法 国家标准 均方根误差分析 临界压力比 有效截面积
下载PDF
对ISO6358-1变压法的评说及建议 被引量:2
4
作者 张士宏 徐文灿 《液压气动与密封》 2016年第4期63-64,4,共3页
针对变压法对两个流量特性参数C、b值进行均方根误差分析及测试都表明,测出C值是可信的;测b值时,仪表的测量精度等级宜使用特级,b值宜大于0.4,不宜测量有最低使用压力要求的气动元件的b值;即使对无最低使用压力要求的气动元件,也要注意... 针对变压法对两个流量特性参数C、b值进行均方根误差分析及测试都表明,测出C值是可信的;测b值时,仪表的测量精度等级宜使用特级,b值宜大于0.4,不宜测量有最低使用压力要求的气动元件的b值;即使对无最低使用压力要求的气动元件,也要注意对于上游压力p1较低,流通能力小的气动元件,由于雷诺数Re太小,会导致测出b值严重失真的问题。 展开更多
关键词 变压法 临界压力比 均方根误差分析 国际标准 流量特性
下载PDF
柔性智能心率服可靠性评价方法
5
作者 张予希 赵艳娇 +3 位作者 孔维良 刘晓元 葛爱雄 刘丽芳 《纺织科学与工程学报》 CAS 2023年第4期26-30,42,共6页
为了比较平均值分析法、相关性检验分析法和均方根误差分析法评价柔性智能心率服可靠性的准确性,先通过真人试验的方法对市面上在售的两款柔性智能心率服进行性能测试,再分别利用上述三种方法对测试数据进行分析,发现均方根误差分析法... 为了比较平均值分析法、相关性检验分析法和均方根误差分析法评价柔性智能心率服可靠性的准确性,先通过真人试验的方法对市面上在售的两款柔性智能心率服进行性能测试,再分别利用上述三种方法对测试数据进行分析,发现均方根误差分析法与实测结果具有较好的一致性,优选出此方法作为柔性智能心率服可靠性的评价方法。 展开更多
关键词 柔性智能心率服 可靠性评价 均方根误差分析
下载PDF
Prediction of representative deformation modulus of longwall panel roof rock strata using Mamdani fuzzy system 被引量:7
6
作者 Mohammad Rezaei Mostafa Asadizadeh +1 位作者 Abbas Majdi Mohammad Farouq Hossaini 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2015年第1期23-30,共8页
Deformation modulus is the important parameter in stability analysis of tunnels, dams and mining struc- tures. In this paper, two predictive models including Mamdani fuzzy system (MFS) and multivariable regression a... Deformation modulus is the important parameter in stability analysis of tunnels, dams and mining struc- tures. In this paper, two predictive models including Mamdani fuzzy system (MFS) and multivariable regression analysis (MVRA) were developed to predict deformation modulus based on data obtained from dilatometer tests carried out in Bakhtiary dam site and additional data collected from longwall coal mines. Models inputs were considered to be rock quality designation, overburden height, weathering, unconfined compressive strength, bedding inclination to core axis, joint roughness coefficient and fill thickness. To control the models performance, calculating indices such as root mean square error (RMSE), variance account for (VAF) and determination coefficient (R^2) were used. The MFS results show the significant prediction accuracy along with high performance compared to MVRA results. Finally, the sensitivity analysis of MFS results shows that the most and the least effective parameters on deformation modulus are weatherin~ and overburden height, respectively. 展开更多
关键词 Deformation modulusDilatometer testMamdani fuzzy systemMultivariable regression analysis
下载PDF
Assessment of air temperatures from different meteorological reanalyses for the East Antarctic region between Zhongshan and Dome A 被引量:1
7
作者 XIE AiHong Ian ALLISON +3 位作者 XIAO CunDe WANG ShiMeng REN JiaWen QIN DaHe 《Science China Earth Sciences》 SCIE EI CAS 2014年第7期1538-1550,共13页
The accuracy of daily mean 2 meter air temperatures from five reanalyses are assessed against in-situ observations from Automatic Weather Stations in East Antarctica for 2005 to 2008. The five reanalyses all explain m... The accuracy of daily mean 2 meter air temperatures from five reanalyses are assessed against in-situ observations from Automatic Weather Stations in East Antarctica for 2005 to 2008. The five reanalyses all explain more than 70% of the average variance, and have annual root mean square errors (RMSE) between 3.4 and 6.9℃. The NOAA reanalyses, NCEP-1, NCEP-2 and 20CRv2, have cool biases of 2.5, 1.4 and 1.5℃, respectively. The ERA Interim and JCDAS reanalyses have warm biases of 1.7 and 2.0℃. All reanalyses generally perform better in the austral spring and worse in winter and autumn. They also show the best performance at an inland plateau site at 2800 m elevation, but are worst at Dome A, the summit of the East Antarctic ice sheet. In general, ERA Interim is superior to the other reanalyses, probably because of its 4D assimilation scheme. The three NOAA reanalyses perform worst; Their assimilation scheme is more constrained by limited observations and 20CRy2 has less input data, assimilating only surface pressure observations. Despite deficiencies and limitations, the reanalyses are still powerful tools for climate studies in the Antarctic region. However, more in-situ observations are required, especially from the vast interior of Antarctica. 展开更多
关键词 East Antarctica reanalysis data surface temperature Zhongshan-Dome A Automatic Weather stations (AWS)
原文传递
Specialized Optical Fiber Sensor for Nondestructive Intrinsic Quality Measurement of Averrhoa Carambola 被引量:1
8
作者 Ahmad Fairuz OMAR Mohd Zubir MATJAFRI 《Photonic Sensors》 SCIE EI CAS 2013年第3期272-282,共11页
This paper presents an innovative and low-cost approach for nondestructive fruit quality analysis. The specialized optical fiber sensor developed and presented in this paper used a monochromatic wavelength, rather tha... This paper presents an innovative and low-cost approach for nondestructive fruit quality analysis. The specialized optical fiber sensor developed and presented in this paper used a monochromatic wavelength, rather than a broad spectrum, to measure the intact carambola (star fruit) intrinsic quality, namely pH and firmness. The main objective of this research was to investigate the two optical fiber sensors used in this work, namely, the optical fiber red system (OF-RS) that operated with the peak sensitivity at 635 nm and the optical fiber near the infrared spectroscopy system (OF-NIRS) that operated with the peak sensitivity at 880nm. Both systems showed good accuracy in the pH and firmness measurement of the intact carambola with the correlation coefficient R over 0.75, and the measurement results were comparable with those of the commercial spectrometer. The best measurement results were obtained using OF-RS (pH: R = 0.876; the root mean square error (RMSE) = 0.211 pH; firmness: R = 0.872; RMSE = 0.909 kgf). 展开更多
关键词 CARAMBOLA FIRMNESS optical fiber sensor PH QUALITY
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部