In this study, we selected 9 typical coal samples with different metamorphic grades as the study subjects,measured their initial 30-min gas desorption at 30℃ and different pressure using a self-developed gas adsorpti...In this study, we selected 9 typical coal samples with different metamorphic grades as the study subjects,measured their initial 30-min gas desorption at 30℃ and different pressure using a self-developed gas adsorption/desorption device. Based on the characteristics of gas desorption from coal samples, we proposed a direct fitting method for measurement of gas content in coalbed, analyzed the effects of sampling time on the measurement results and determined the reasonable sampling time of coal samples with different metamorphic grades at different gas adsorption pressure at equilibrium. The results show that (1)the error of gas contents obtained using the direct fitting method relative to that obtained using indirect method is less than 10%, which meets the actual on-site requirements and verifies the feasibility of the direct fitting method;(2) when the relative error is controlled within ±10%, the reasonable sampling time of coal samples is linearly related to the gas adsorption pressure at equilibrium;(3) the reasonable sampling time of coal samples with the same metamorphic grade exhibits a shortening trend with increasing gas adsorption pressure at equilibrium;(4) for coal samples with similar gas adsorption pressure at equilibrium, the reasonable sampling time of coal samples displays a shortening trend with increasing metamorphic grade. Overall, the study provides a basis for improving the measurement accuracy of gas content in coalbed.展开更多
For the linear crack skeleton of railway bridges with irregular strike,it is difficult to accurately express the crack contour feature by using a single smoothing fitting algorithm.In order to improve the measurement ...For the linear crack skeleton of railway bridges with irregular strike,it is difficult to accurately express the crack contour feature by using a single smoothing fitting algorithm.In order to improve the measurement accuracy,a polynomial curve fitting was proposed,which used the calibration point of crack contour as the boundary point,and then put them all together to produce a continuous contour curve to achieve the crack length measurement.The method was tested by measuring the linar cracks with different shapes.It is shown that this proposed algorithm can not only solve the jagged problem generated in the crack skeleton extraction process,but also improve the crack length measurement accuracy.The relative deviation is less than 0.15,and the measurement accuracy is over 98.05%,which provides a more effective means for the crack length measurement in railway bridges.展开更多
Based on the statistical analysis of API （air pollution index）, the study improves the layout of the site in the downtown of Nanjing and the surroundings. Through selecting more relevant factors to establish the API...Based on the statistical analysis of API （air pollution index）, the study improves the layout of the site in the downtown of Nanjing and the surroundings. Through selecting more relevant factors to establish the API regression equation and making the inversion of API data in simulated sites, the interpolation values of API in both actual sites and simulated sites have been calculated. The methods include IDW （inverse distance weighting） interpolation, Spline interpolation, and Kriging interpolation Spherical model, Exponential model and the Gaussian model. Meanwhile, through the cross-validation to test the results of interpolation in different models or parameters, the study also obtains the best fit of the interpolation model or parameters. In addition, IDW p = 3, fitting coefficient of 0.644; Spline interpolation w = 1, the fitting coefficient of 0.972; Kriging interpolation, Gaussian, fitting coefficient of 0.684. The study indicates that in best fitting model, the parameters after in increasing the simulated site are not in line with the ones previous. The result shows that it is best to test different data separately and select the appropriate interpolation model, but not blindly use the same spatial interpolation. After the increasing of the stimulated site, the API estimated results in three interpolation methods are consistent with the spatial distribution trend. In the aspect of calculating the range, the improvement close the results between 3 interpolation methods and increase of the stimulated sites, and the values of Spline interpolation and Kriging interpolation is closer.展开更多
A method of measuring turbidity based on a multi-wavelength spectral sensor is proposed by using SFH4737 broad-band infrared LED,a multi-wavelength spectral sensor and independently developed data processing software....A method of measuring turbidity based on a multi-wavelength spectral sensor is proposed by using SFH4737 broad-band infrared LED,a multi-wavelength spectral sensor and independently developed data processing software.Combining multiple wavelength data from the sensor,the unitary and multivariate fitting models were constructed to investigate the relationship among light intensity information,absorbance and turbidity,respectively.The turbidity of the actual water bodies was measured separately by using proposed method and a commercially visible spectrophotometer.The independent-samples T test(p>0.05)showed that there was no significant difference between the method in this paper and the standard assay method.The method is simple and inexpensive,and can be applied to the rapid detection of water turbidity,providing a new way of industrial online measurement.展开更多
The weather system, meteorological conditions, and microphysics of cloud, fog, and rain droplets are studied during the formation, growth, maintenance, and shedding periods of ice accretion on wires in Enshi, Hubei Pr...The weather system, meteorological conditions, and microphysics of cloud, fog, and rain droplets are studied during the formation, growth, maintenance, and shedding periods of ice accretion on wires in Enshi, Hubei Province in China using 2008/2009 and 2009/2010 winter observations. The comprehensive observations include data of visibility, microphysics of fog and rain droplets, and ice thickness, as well as data from an automated weather station and other routinely recorded meteorological data. The results show that icing occurred during the passage of a cold front, with a high-pressure system and a cold temperature trough at 850 hPa, and a southeasterly at 500 hPa that provided abundant moisture. Ice formation usually started in the evening or early morning, and ice shed around noon the following day when the temperature was -1℃ to 0℃. The averaged liquid water content of the fog droplet was distinctly greater during the growth period than during the other three periods, and there was precipitation during the growth period in each case of ice accretion. The growth rate of the ice thickness was clearly correlated with the liquid water content, with a correlation coefficient of 0.62. Simulations using empirical equations were carried out, and the simulated ice thickness agreed with observations fairly well.展开更多
基金the support of the National Natural Science Foundation of China(Nos.51674158,51604168 and 51504142)the Natural Science Foundation of Shandong Province(No.ZR2016EEQ18)+2 种基金the SDUST Research Fund(No.2015JQJH105)the Qingdao Postdoctoral Applied Research Project(No.2015204)the Taishan Scholar Talent Team Support Plan for Advantaged&Unique Discipline Areas
文摘In this study, we selected 9 typical coal samples with different metamorphic grades as the study subjects,measured their initial 30-min gas desorption at 30℃ and different pressure using a self-developed gas adsorption/desorption device. Based on the characteristics of gas desorption from coal samples, we proposed a direct fitting method for measurement of gas content in coalbed, analyzed the effects of sampling time on the measurement results and determined the reasonable sampling time of coal samples with different metamorphic grades at different gas adsorption pressure at equilibrium. The results show that (1)the error of gas contents obtained using the direct fitting method relative to that obtained using indirect method is less than 10%, which meets the actual on-site requirements and verifies the feasibility of the direct fitting method;(2) when the relative error is controlled within ±10%, the reasonable sampling time of coal samples is linearly related to the gas adsorption pressure at equilibrium;(3) the reasonable sampling time of coal samples with the same metamorphic grade exhibits a shortening trend with increasing gas adsorption pressure at equilibrium;(4) for coal samples with similar gas adsorption pressure at equilibrium, the reasonable sampling time of coal samples displays a shortening trend with increasing metamorphic grade. Overall, the study provides a basis for improving the measurement accuracy of gas content in coalbed.
基金National Defense Pre-Research Fund Project(No.060601)Wanqiao Education Fund Project(No.06010023)。
文摘For the linear crack skeleton of railway bridges with irregular strike,it is difficult to accurately express the crack contour feature by using a single smoothing fitting algorithm.In order to improve the measurement accuracy,a polynomial curve fitting was proposed,which used the calibration point of crack contour as the boundary point,and then put them all together to produce a continuous contour curve to achieve the crack length measurement.The method was tested by measuring the linar cracks with different shapes.It is shown that this proposed algorithm can not only solve the jagged problem generated in the crack skeleton extraction process,but also improve the crack length measurement accuracy.The relative deviation is less than 0.15,and the measurement accuracy is over 98.05%,which provides a more effective means for the crack length measurement in railway bridges.
文摘Based on the statistical analysis of API （air pollution index）, the study improves the layout of the site in the downtown of Nanjing and the surroundings. Through selecting more relevant factors to establish the API regression equation and making the inversion of API data in simulated sites, the interpolation values of API in both actual sites and simulated sites have been calculated. The methods include IDW （inverse distance weighting） interpolation, Spline interpolation, and Kriging interpolation Spherical model, Exponential model and the Gaussian model. Meanwhile, through the cross-validation to test the results of interpolation in different models or parameters, the study also obtains the best fit of the interpolation model or parameters. In addition, IDW p = 3, fitting coefficient of 0.644; Spline interpolation w = 1, the fitting coefficient of 0.972; Kriging interpolation, Gaussian, fitting coefficient of 0.684. The study indicates that in best fitting model, the parameters after in increasing the simulated site are not in line with the ones previous. The result shows that it is best to test different data separately and select the appropriate interpolation model, but not blindly use the same spatial interpolation. After the increasing of the stimulated site, the API estimated results in three interpolation methods are consistent with the spatial distribution trend. In the aspect of calculating the range, the improvement close the results between 3 interpolation methods and increase of the stimulated sites, and the values of Spline interpolation and Kriging interpolation is closer.
基金National Natural Science Foundation of China(No.71801108)Natural Science Fund for Colleges and Universities of Anhui Province(No.KJ2017ZD32)。
文摘A method of measuring turbidity based on a multi-wavelength spectral sensor is proposed by using SFH4737 broad-band infrared LED,a multi-wavelength spectral sensor and independently developed data processing software.Combining multiple wavelength data from the sensor,the unitary and multivariate fitting models were constructed to investigate the relationship among light intensity information,absorbance and turbidity,respectively.The turbidity of the actual water bodies was measured separately by using proposed method and a commercially visible spectrophotometer.The independent-samples T test(p>0.05)showed that there was no significant difference between the method in this paper and the standard assay method.The method is simple and inexpensive,and can be applied to the rapid detection of water turbidity,providing a new way of industrial online measurement.
基金supported by National Key Technology R&D Program of China (Grant No. 2008BAC48B01)National Natural Science Foundation of China (Grant No. 40775012)+1 种基金the Jiangsu Province Qinglan Project for Cloud Fog Precipitation and the Aerosol Research Groupa project funded by the Priority Acadenic Program Development of Jiangsu Higher Education Institutions
文摘The weather system, meteorological conditions, and microphysics of cloud, fog, and rain droplets are studied during the formation, growth, maintenance, and shedding periods of ice accretion on wires in Enshi, Hubei Province in China using 2008/2009 and 2009/2010 winter observations. The comprehensive observations include data of visibility, microphysics of fog and rain droplets, and ice thickness, as well as data from an automated weather station and other routinely recorded meteorological data. The results show that icing occurred during the passage of a cold front, with a high-pressure system and a cold temperature trough at 850 hPa, and a southeasterly at 500 hPa that provided abundant moisture. Ice formation usually started in the evening or early morning, and ice shed around noon the following day when the temperature was -1℃ to 0℃. The averaged liquid water content of the fog droplet was distinctly greater during the growth period than during the other three periods, and there was precipitation during the growth period in each case of ice accretion. The growth rate of the ice thickness was clearly correlated with the liquid water content, with a correlation coefficient of 0.62. Simulations using empirical equations were carried out, and the simulated ice thickness agreed with observations fairly well.
