Circular thin-plate electrostatic sensors are promising in gas path monitoring due to their advantages of non-intrusiveness and easy installation. The spatial sensitivity and filtering effect are two important perform...Circular thin-plate electrostatic sensors are promising in gas path monitoring due to their advantages of non-intrusiveness and easy installation. The spatial sensitivity and filtering effect are two important performance parameters. In this paper, an analytically mathematical model of induced charge on a circular thin-plate electrode is first derived. Then the spatial sensitivity and filtering effect of the circular electrostatic sensor are investigated by numerical calculations. Finally,experimental studies are performed to testify the theoretical results. Both theoretical and experimental results demonstrate that circular thin-plate electrostatic sensors act as a low-pass filter in the spatial frequency domain, and both the spatial filtering effect and the temporal frequency response characteristics depend strongly on the spatial position and velocity of the charged particle. These conclusions can provide guidelines for the optimal design of circular thin-plate electrostatic sensors.展开更多
In order to study morphological diversity of codling moth, Cydia pomonella （L.） using thin-plate spline analysis, nine geographical populations from four north western provinces of Iran namely East Azarbayjan, West ...In order to study morphological diversity of codling moth, Cydia pomonella （L.） using thin-plate spline analysis, nine geographical populations from four north western provinces of Iran namely East Azarbayjan, West Azarbayjan, Ardebil and Zandjan were collected during 2003 and 2004. 575 and 564 images were prepared from fore and hind wings, respectively. Then 15 and 11 landmarks were determined from fore and hind wings, respectively. With transforming of landmark＇s two dimensional coordinate data into partial warp scores, 26 and 18 scores were generated for fore and hind wings, respectively. Cluster analysis based on wing shape variables using Ward＇s algorithm assigned nine geographical populations into two groups. The pattern of grouping based on fore and hind wings was different in both sexes. Principal component analysis revealed discrimination between geographic populations and confirmed the result of cluster analysis. Among environmental parameters, wind speed showed the highest correlation with wing shape variables. Non significant correlation was observed between geographic and morphological distance matrices as revealed by Mantel test.展开更多
As part of a joint effort to construct an atmospheric forcing dataset for China's Mainland with high spatiotemporal reso- lution, a new approach is proposed to construct gridded near-surface temperature, relative ...As part of a joint effort to construct an atmospheric forcing dataset for China's Mainland with high spatiotemporal reso- lution, a new approach is proposed to construct gridded near-surface temperature, relative humidity, wind speed and surface pressure with a resolution of 1 km× 1 km. The approach comprises two steps： （1） fit a partial thin-plate smoothing spline with orography and reanalysis data as explanatory variables to ground-based observations for estimating a trend surface; （2） apply a simple kriging procedure to the residual for trend surface correction. The proposed approach is applied to observations collected at approximately 700 stations over China's Mainland. The generated forcing fields are compared with the corresponding components of the National Centers for Environmental Predic- tion （NCEP） Climate Forecast System Reanalysis dataset and the Princeton meteorological forcing dataset. The comparison shows that, both within the station network and within the resolutions of the two gridded datasets, the interpolation errors of the proposed approach are markedly smaller than the two gridded datasets.展开更多
We evaluated the spatial and temporal patterns of forest fires in two fire seasons (March to June and September to November) from 1996 to 2010 in Jilin Province, China, using the Canadian Forest Fire Weather Index Sys...We evaluated the spatial and temporal patterns of forest fires in two fire seasons (March to June and September to November) from 1996 to 2010 in Jilin Province, China, using the Canadian Forest Fire Weather Index System. Fire data were obtained from the Provincial Fire Agency, and historical climate records of daily weather observations were collected from 36 weather stations in Jilin and its neighboring provinces. A linear regression model was used to analyze linear trends between climate and fire weather indices with time treated as an independent variable. Correlation analysis was used to detect correlations between fire frequency, areas burned, and fire weather indices. A thin-plate smooth spline model was used to interpolate the point data of 36 weather stations to generate a surface covering the whole province. Our analyses indicated fire frequency and areas burned were significantly correlated with fire weather indices. Overall, the Canadian Forest Fire Weather Index System appeared to be work well for determining the fire danger rating in Jilin Province. Also, our analyses indicated that in the forthcoming decades, the overall fire danger in March and April should decrease across the province, but the chance of a large fire in these months would increase. The fire danger in the fall fire season would increase in the future, and the chance of large fire would also increase. Historically, because most fires have occurred in the spring in Jilin Province, such a shift in the future fire danger between the two fire seasons would be beneficial for the province's fire management.展开更多
We propose a strategy for designing the cylindrical acoustic cloak with thin-plate metamaterials.The inhomogeneous cloaking shell as derived by transformation acoustics is first discretized into a three-layer anisotro...We propose a strategy for designing the cylindrical acoustic cloak with thin-plate metamaterials.The inhomogeneous cloaking shell as derived by transformation acoustics is first discretized into a three-layer anisotropic metafluid,and their material parameters are optimized by minimizing the external scatterings.Then these metafluids are practically realized by thin-plate structures according to the metamaterial concept.As an example,an acoustic cloak is designed with nine layers of thin plate and totally 900 plate units.Numerical simulations are performed to assess the cloaking performance of the designed structure.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51275520,50805142)
文摘Circular thin-plate electrostatic sensors are promising in gas path monitoring due to their advantages of non-intrusiveness and easy installation. The spatial sensitivity and filtering effect are two important performance parameters. In this paper, an analytically mathematical model of induced charge on a circular thin-plate electrode is first derived. Then the spatial sensitivity and filtering effect of the circular electrostatic sensor are investigated by numerical calculations. Finally,experimental studies are performed to testify the theoretical results. Both theoretical and experimental results demonstrate that circular thin-plate electrostatic sensors act as a low-pass filter in the spatial frequency domain, and both the spatial filtering effect and the temporal frequency response characteristics depend strongly on the spatial position and velocity of the charged particle. These conclusions can provide guidelines for the optimal design of circular thin-plate electrostatic sensors.
文摘In order to study morphological diversity of codling moth, Cydia pomonella （L.） using thin-plate spline analysis, nine geographical populations from four north western provinces of Iran namely East Azarbayjan, West Azarbayjan, Ardebil and Zandjan were collected during 2003 and 2004. 575 and 564 images were prepared from fore and hind wings, respectively. Then 15 and 11 landmarks were determined from fore and hind wings, respectively. With transforming of landmark＇s two dimensional coordinate data into partial warp scores, 26 and 18 scores were generated for fore and hind wings, respectively. Cluster analysis based on wing shape variables using Ward＇s algorithm assigned nine geographical populations into two groups. The pattern of grouping based on fore and hind wings was different in both sexes. Principal component analysis revealed discrimination between geographic populations and confirmed the result of cluster analysis. Among environmental parameters, wind speed showed the highest correlation with wing shape variables. Non significant correlation was observed between geographic and morphological distance matrices as revealed by Mantel test.
基金supported by the National Program on Key Basic Research Project of China (Grant Nos.2010CB951604 and 2010CB950703)the National Natural Science Foundation of China General Program (Grant Nos.40975062 and 40875062)+2 种基金R&D Special Fund for Nonprofit Industry (Grant No.Meteorology GYHY201206008)the Key Technologies Research and Development Program of China (Grant No.2013BAC05B04)the Fundamental Research Funds for the Central Universities (Grant No.2012LYB42)
文摘As part of a joint effort to construct an atmospheric forcing dataset for China's Mainland with high spatiotemporal reso- lution, a new approach is proposed to construct gridded near-surface temperature, relative humidity, wind speed and surface pressure with a resolution of 1 km× 1 km. The approach comprises two steps： （1） fit a partial thin-plate smoothing spline with orography and reanalysis data as explanatory variables to ground-based observations for estimating a trend surface; （2） apply a simple kriging procedure to the residual for trend surface correction. The proposed approach is applied to observations collected at approximately 700 stations over China's Mainland. The generated forcing fields are compared with the corresponding components of the National Centers for Environmental Predic- tion （NCEP） Climate Forecast System Reanalysis dataset and the Princeton meteorological forcing dataset. The comparison shows that, both within the station network and within the resolutions of the two gridded datasets, the interpolation errors of the proposed approach are markedly smaller than the two gridded datasets.
基金financially supported by the National Natural Science Foundation of China(31470497)Project 2013-158,Jilin Provincial Education Department+1 种基金Project 2013-007,Jilin Provincial Forestry Departmentsupported by the Program for New Century Excellent Talents in the University(NCET-12-0726)
文摘We evaluated the spatial and temporal patterns of forest fires in two fire seasons (March to June and September to November) from 1996 to 2010 in Jilin Province, China, using the Canadian Forest Fire Weather Index System. Fire data were obtained from the Provincial Fire Agency, and historical climate records of daily weather observations were collected from 36 weather stations in Jilin and its neighboring provinces. A linear regression model was used to analyze linear trends between climate and fire weather indices with time treated as an independent variable. Correlation analysis was used to detect correlations between fire frequency, areas burned, and fire weather indices. A thin-plate smooth spline model was used to interpolate the point data of 36 weather stations to generate a surface covering the whole province. Our analyses indicated fire frequency and areas burned were significantly correlated with fire weather indices. Overall, the Canadian Forest Fire Weather Index System appeared to be work well for determining the fire danger rating in Jilin Province. Also, our analyses indicated that in the forthcoming decades, the overall fire danger in March and April should decrease across the province, but the chance of a large fire in these months would increase. The fire danger in the fall fire season would increase in the future, and the chance of large fire would also increase. Historically, because most fires have occurred in the spring in Jilin Province, such a shift in the future fire danger between the two fire seasons would be beneficial for the province's fire management.
基金supported by the National Natural Science Foundation of China(grant numbers 10832002,11172038,11072031,and 11221202)the National Basic Research Program of China(grant number 2011CB610302)+1 种基金Program for New Century Excellent Talents in University(grant number NCET-11-0794)Beijing Higher Education Young Elite Teacher Project.
文摘We propose a strategy for designing the cylindrical acoustic cloak with thin-plate metamaterials.The inhomogeneous cloaking shell as derived by transformation acoustics is first discretized into a three-layer anisotropic metafluid,and their material parameters are optimized by minimizing the external scatterings.Then these metafluids are practically realized by thin-plate structures according to the metamaterial concept.As an example,an acoustic cloak is designed with nine layers of thin plate and totally 900 plate units.Numerical simulations are performed to assess the cloaking performance of the designed structure.
