针对现有跨垄式采茶机导航中心线提取效率低的问题,该研究提出一种基于机器视觉跟踪生长ROI茶垄间导航线提取算法。首先采用固定ROI(region of interest)方法,选取图像左下方区域为第一块ROI,在ROI内进行超绿指数灰度化,最大类方差法分...针对现有跨垄式采茶机导航中心线提取效率低的问题,该研究提出一种基于机器视觉跟踪生长ROI茶垄间导航线提取算法。首先采用固定ROI(region of interest)方法,选取图像左下方区域为第一块ROI,在ROI内进行超绿指数灰度化,最大类方差法分割茶垄道路与背景,通过形态学操作对图像进行增强与降噪,使用最大连通域检测操作提取ROI内的坐标信息与特征点,根据ROI提取的坐标信息动态生成ROI,直到整个图像中所有茶垄道路信息提取完成,最后采用最小二乘法获取跨垄式采茶机底盘在垄间行驶的导航线。该方法经过连续帧测试,处理一帧1920×1080像素图像的平均时间为18 ms,该研究算法与人工提取导航线的航向角平均误差为0.405°,标准差为0.463°,可在一定杂草、落叶干扰的情况下完成导航角提取。展开更多
为加速AprilTag检测,提出了一种基于改进YOLOv5s预提取RoI(region of interest)的AprilTag检测方法。改进YOLOv5s网络,在输入灰度图像的单通道模式下,分别采用Ghost Bottleneck和ConvNeXt Block替换主干网络和颈部网络的C3和瓶颈模块,...为加速AprilTag检测,提出了一种基于改进YOLOv5s预提取RoI(region of interest)的AprilTag检测方法。改进YOLOv5s网络,在输入灰度图像的单通道模式下,分别采用Ghost Bottleneck和ConvNeXt Block替换主干网络和颈部网络的C3和瓶颈模块,提高模型的推理速度和泛化能力;通过亮度增强扩充数据集,提高模型鲁棒性。基于改进的YOLOv5网络进行AprilTag预识别,通过输出锚框划分RoI进行AprilTag检测,缩小图像处理范围,提高计算效率。实验结果表明,提出的AprilTag检测方法在1080P图像下FPS比传统AprilTag算法提高了77.42%以上。展开更多
The cold regions are located in high latitudes and cold climates.The local excellent ornamental plant resources are relatively scarce.The plant species that are suitable for both ornamental and productive benefits of ...The cold regions are located in high latitudes and cold climates.The local excellent ornamental plant resources are relatively scarce.The plant species that are suitable for both ornamental and productive benefits of landscape of flower sea construction are also even fewer.Therefore,it is imperative to introduce and screen the plant resources suitable for cold regions to create the landscape of flower sea.The rape,an oilseed crop,was used as a research object in order to create a productive flower landscape with both ornamental and economic values in cold regions.Four rape flower varieties,Qingza No.5,7,9,and 11,were introduced from Qinghai Hufeng Agricultural Science and Technology Group Co.,Ltd.They were planted in the experimental practice base of Northeast Agricultural University in three batches.Development characteristics and seed yield of rape flowers on different sowing dates were studied.The fuzzy probability method was used to comprehensively evaluate the varieties.The results showed that the rape flowers grew well in Harbin City during the experimental sowing period,which could form a good landscape of flower sea and had a considerable rapeseed yield.It could be widely used in cold urban and rural areas,such as Harbin City.In view of the experimental results,the strategies of creating a productive landscape of rape flower sea were proposed and the economic benefits were analyzed.It could change the status quo of a uniform landscape of flower sea in cold regions,help the development of rural tourism,and promote local economic income.展开更多
[Background]As one of the most serious environmental issues in the world,soil erosion causes water pollution,reservoir siltation,soil productivity decline,thus threatens agricultural systems and even affects global cl...[Background]As one of the most serious environmental issues in the world,soil erosion causes water pollution,reservoir siltation,soil productivity decline,thus threatens agricultural systems and even affects global climate.The benefits of ecological soil and water conservation measures(ESWCMs,such as micro basins tillage and contour tillage)are widely understood,including runoff and soil loss reducing to a certain extent when compared with traditional tillage.While few studies have focused on China’s different soil types and erosion characteristics.[Methods]We reviewed literature from Web of Science,Scopus,and China National Knowledge Infrastructure using terms like“Conservation practice”“Contour tillage”“Runoff”“Sediment”“Erosion”and“China”and retained literatures based on criteria such as natural or simulated precipitation,runoff or soil loss data,reported replications and statistics,recorded factors like location and slope,and at least two data pairs per group.Ultimately,49 literatures were selected to quantify the impacts on different ESWCMs and identify the slope and precipitation for the greatest runoff and sediment reduction by calculating the log response ratio(LRR).[Results]The three regions’soil and water conservation benefits varied due to the differences in climate,terrain,and soil properties:1)ESWCMs applied in the black soil region of Northeast China were the most effective in reducing runoff and soil loss(66.65%runoff and 75.83%sediment),followed by those applied in the purple soil region of Southwest China(39.98%runoff and 58.30%sediment)and loess soil region of Northwest China(16.36%runoff and 32.44%sediment).2)Micro basins tillage(MBT)(71.79%runoff and 87.03%sediment)no-tillage with mulch(NTM)(17.30%runoff and 32.51%sediment),collecting soil to form a ridge with no-till(CSNT)(55.78%runoff and 71.36%sediment reduction)were the most efficient soil and water conservation measures in controlling water erosion in the black soil of Northeast China,the loess soil region of Northwest China and the purple soil region of Southwest China,respectively.3)The slope gradients ranged from 0-3°,>3°-5°and>10°-15°(0-3°:97.09%;>3°-5°:74.62%;and>10°-15°:39.41%)caused the largest reduction of runoff in the black soil region of Northeast China,the loess soil region of Northwest China,and the purple soil region of Southwest China.Meanwhile,the effects of sediment reduction were the most obvious,ranging from 0-3°,>10°-15°,and>20°-25°(0-3°:89.32%;>10°-15°:75.94%;and>20°-25°:67.25%).4)The effect of ESWCMs under rainstorms was the most obvious in the black soil region of Northeast China.The effect on runoff reduction under light rain in the purple soil region of Southwest China was the most obvious,but it failed to pass the significance test in sediment reduction.[Conclusions]The results provided optimal conservation tillage measures for three regions,different slopes and different rainfalls,and provided data support for reducing regional soil and water loss in China.展开更多
This paper conducted a systematic survey and zoogeographical region analysis of the family Sphingidae in the Guokui Mountain,Heilongjiang Province.Collections were made from May 2023 to August 2024 using the light-tra...This paper conducted a systematic survey and zoogeographical region analysis of the family Sphingidae in the Guokui Mountain,Heilongjiang Province.Collections were made from May 2023 to August 2024 using the light-trap method.A total of 14 species and 11 subspecies from 18 genera and three subfamilies were recorded.One species(Ambulyx tobii)and two subspecies(Ambulyx japonica koreana and Clanis undulosa undulosa)were new records for Heilongjiang Province.The study showed that the subfamily Smerinthinae had the most species(subspecies),while the subfamily Sphinginae had the fewest.Among the world's zoogeographical region,most species(subspecies)in the Guokui Mountain belonged to the palearctic region,with eight species and seven subspecies were also found in the oriental region.This indicated a close biogeographic connection between the two regions.Among the Chinese zoogeographical regions,the northeastern territory,northern territory and northwestern territory had the most abundant species(subspecies).It was also found that the distribution pattern types of hawkmoths in the Guokui Mountain were diverse,with the'northeastern territory-northern territory-northwestern territory'and'northeastern territory-northern territorynorthwestern territory-western plateau-southwestern territory-central territory-southeastern territory'types having the most species(subspecies).In addition,the Guokui Mountain hawkmoths were mostly distributed interregionally.The distribution patterns that contained the northeastern territory were the most numerous,followed by the northern territory.The rich diversity of the family Sphingidae in the Guokui Mountain was closely related to the unique climate,environment and vegetation types in the area.The results could help to improve the biodiversity database of Heilongjiang Province and researches on hawkmoths.展开更多
针对机器视觉轴承内圈侧面复杂形状尺寸检测精度低的问题,提出根据检测目标建立小面积感兴趣区域(Region of Interest,ROI)的自适应选取方法和基于Zernike矩的ROI亚像素级边缘提取方法,大幅提升了轴承内圈尺寸的检测精度。首先分别拍摄...针对机器视觉轴承内圈侧面复杂形状尺寸检测精度低的问题,提出根据检测目标建立小面积感兴趣区域(Region of Interest,ROI)的自适应选取方法和基于Zernike矩的ROI亚像素级边缘提取方法,大幅提升了轴承内圈尺寸的检测精度。首先分别拍摄轴承内圈左侧与右侧轮廓图像,对图像进行预处理。在此基础上,通过角点检测融合像素扫描的方法实现自适应ROI选取,解决了因轴承内圈移动引起的小面积ROI边缘误判问题;使用Canny算子提取ROI的像素级边缘,再用改进的Zernike矩算法得到亚像素级边缘。最后,分别对ROI中提取的边缘进行最小二乘圆拟合和直线拟合,根据像素当量与视场间隔将图像中各尺寸转换为轴承内圈实际尺寸。实验结果表明:所提方法测量的标准不确定度低于0.005 mm,满足轴承尺寸高精度检测的要求,对于实现轴承检测的自动化有实际意义。展开更多
We assembled approximately 328 seismic records. The data set was from 4 digitally recording long-period and broadband stations of CDSN. We carried out the inversion based on the partitioned waveform inversion (PWI). I...We assembled approximately 328 seismic records. The data set was from 4 digitally recording long-period and broadband stations of CDSN. We carried out the inversion based on the partitioned waveform inversion (PWI). It partitions the large-scale optimization problem into a number of independent small-scale problems. We adopted surface waveform inversion with an equal block (2((2() discretization in order to acquire the images of shear velocity structure at different depths (from surface to 430 km) in the crust and upper-mantle. The resolution of all these anomalies has been established with (check-board( resolution tests. These results show significant difference in velocity, lithosphere and asthenosphere structure between South China Sea and its adjacent regions.展开更多
This study investigated the temperature field and thawing depth of wide embankment for expressway in permafrost regions based on numerical analysis by using finite element method(FEM).According to specific embankment ...This study investigated the temperature field and thawing depth of wide embankment for expressway in permafrost regions based on numerical analysis by using finite element method(FEM).According to specific embankment section of Qinghai-Tibet highway,computational region for numerical analysis was defined.And numerical model was developed through FEM software named as ABAQUS and was verified by field observed data.The effects by width and height of embankment on the thermal regime of computational region were analyzed based on FEM modeling.Numerical analysis showed that embankment construction has serious disturbance on the thermal stability of ground permafrost showing as annual average ground temperature and the maximum thawing depth keeps increasing with service time increasing.And larger embankment width leads to poorer thermal stability and more serious uneven temperature field of embankment.Raising embankment height can improve the thermal stability; however,the improvement is restricted for wide embankment and it cannot change the degradation trend of thermal stability with service life increasing.Thus,to construct expressway with wide embankment in permafrost regions of Qinghai-Tibet Plateau,effective measures need to be considered to improve the thermal stability of underlying permafrost.展开更多
To reveal the influencing factors and changing rules for the hydrothermal interaction process of highway subgrade, the field measurements of Shiwei-Labudalin Highway in Inner Mongolia, China was conducted for 3 years,...To reveal the influencing factors and changing rules for the hydrothermal interaction process of highway subgrade, the field measurements of Shiwei-Labudalin Highway in Inner Mongolia, China was conducted for 3 years, based on which the freezing-thawing rules and water content changing characteristics were analyzed. The main results show the subgrade presents a frequent freezing-thawing alternation, and the water content of subgrade exhibits an obvious seasonal alternation. The subbase has the maximum water content, while the base has the minimum water content. The change of water flux is concentrated in the thawing period and consistent with the change of temperature gradient. The subbase layer has the most active water flux due to the heat absorption and impermeability of pavement that easily causes the water accumulation in this layer. Therefore, the prevention and treatment for the freezing-thawing disease should be started from heat insulation and water resistance.展开更多
The current ventilation condition of the hot and humid regions was analyzed through on-site investigation. It is found that residents in this region expect to improve indoor thermal environment through natural ventila...The current ventilation condition of the hot and humid regions was analyzed through on-site investigation. It is found that residents in this region expect to improve indoor thermal environment through natural ventilation as much as possible. Then,it comes to a conclusion by the field test that natural ventilation has certain practical effect on improving indoor thermal environment. CFD simulation software is employed to verify the test result. Based on PMV modified model,and according to norms,geography and climate combined with the measured and simulated results,the application of the time and effectiveness of natural ventilation in hot and humid region were analyzed,to some extent,providing a basis for reducing the air-conditioner's runtime with natural ventilation.展开更多
We have conducted some studies on 3 ground cherry cultivars'Artaskaja'.'Bushkaja'and'Maksmorfikaja'introduced from Russia.The results indicated that these cultivars could survive temperature -4...We have conducted some studies on 3 ground cherry cultivars'Artaskaja'.'Bushkaja'and'Maksmorfikaja'introduced from Russia.The results indicated that these cultivars could survive temperature -40℃ during severe winter in Harbin,China and had high drought and disease resistance,the average weight of each fruit reached 2.78g,the contents of Vc and soluble solid exceeded 30mg/100g and 12%,respectively.Not only does the fruits suit for fresh market,but also for processing.Ground cherry is a promising new fruit crop in cold region.展开更多
A novel multi-view 3D face registration method based on principal axis analysis and labeled regions orientation called local orientation registration is proposed.The pre-registration is achieved by transforming the mu...A novel multi-view 3D face registration method based on principal axis analysis and labeled regions orientation called local orientation registration is proposed.The pre-registration is achieved by transforming the multi-pose models to the standard frontal model＇s reference frame using the principal axis analysis algorithm.Some significant feature regions, such as inner and outer canthus, nose tip vertices, are then located by using geometrical distribution characteristics.These regions are subsequently employed to compute the conversion parameters using the improved iterative closest point algorithm, and the optimal parameters are applied to complete the final registration.Experimental results implemented on the proper database demonstrate that the proposed method significantly outperforms others by achieving 1.249 and 1.910 mean root-mean-square measure with slight and large view variation models, respectively.展开更多
Ⅰ. An analysis of the development trend of the economy in the north,middle aud south coastal regions or China since China began to implementreform and open
Introduction Atherosclerosis is a potentially life-threatening disease of large arteries that is strongly associated with systemic risk factors such as hypercholesterolemia,hypertension,smoking,and diabetes. However,a...Introduction Atherosclerosis is a potentially life-threatening disease of large arteries that is strongly associated with systemic risk factors such as hypercholesterolemia,hypertension,smoking,and diabetes. However,atherosclerosis develops as a展开更多
Background:Segregation distortion(SD)is a common phenomenon among stable or segregating populations,and the principle behind it still puzzles many researchers.The F2:3 progenies developed from the wild cotton species ...Background:Segregation distortion(SD)is a common phenomenon among stable or segregating populations,and the principle behind it still puzzles many researchers.The F2:3 progenies developed from the wild cotton species of the D genomes were used to investigate the possible plant transcription factors within the segregation distortion regions(SDRs).A consensus map was developed between two maps from the four D genomes,map A derived from F2:3 progenies of Gossypium klotzschianum and G.davidsonii while Map B from G.thurberi and G.trilobum F2:3 generations.In each map,188 individual plants were used.Results:The consensus linkage map had 1492 markers across the 13 linkage groups with a map size of 1467.445 cM and an average marker distance of 1.0370 cM.Chromosome D502 had the highest percentage of SD with 58.6%,followed by Chromosome D507 with 47.9%.Six thousand and thirty-eight genes were mined within the SDRs on chromosome D502 and D507 of the consensus map.Within chromosome D502 and D507,2308 and 3730 genes were mined,respectively,and were found to belong to 1117 gourp out of which 622 groups were common across the two chromosomes.Moreover,genes within the top 9 groups related to plant resistance genes(R genes),whereas 188 genes encoding protein kinase domain(PF00069)comprised the largest group.Further analysis of the dominant gene group revealed that 287 miRNAs were found to target various genes,such as the gra-miR398,gramiR5207,miR164a,miR164b,miR164c among others,which have been found to target top-ranked stress-responsive transcription factors such as NAC genes.Moreover,some of the stress-responsive cis-regulatory elements were also detected.Furthermore,RNA profiling of the genes from the dominant family showed that higher numbers of genes were highly upregulated under salt and osmotic stress conditions,and also they were highly expressed at different stages of fiber development.Conclusion:The results indicated the critical role of the SDRs in the evolution of the key regulatory genes in plants.展开更多
Forest fire accidents caused by distribution line faults occur frequently,resulting in heavy impacts on people’s safety and social and economic development.Currently,there are few risk assessments for forest fires in...Forest fire accidents caused by distribution line faults occur frequently,resulting in heavy impacts on people’s safety and social and economic development.Currently,there are few risk assessments for forest fires induced by over-head distribution lines,and existing assessment methods may have difficulties in data acquisition.On this basis,a novel as-sessment framework based on an analytic hierarchy process,a Bayesian network and a Fussel-Vesely importance metric is proposed in this paper.The framework combines field research and historical operation and maintenance data to assess the regional-scale risk of forest fires induced by overhead distribution lines to derive the probability of forest fires and to identify high-risk lines and key hazard events in the assessment region.Finally,taking the southern Anhui region as an ex-ample,the annual fire probability of forest fires induced by overhead distribution lines in the southern Anhui region is 5.88%,and rectification measures are proposed.This study provides management with a complete assessment framework that optimizes the difficulty of data collection and allows for additional targeted corrective measures to be proposed for the entire region and route on the basis of the assessment results.展开更多
文摘针对现有跨垄式采茶机导航中心线提取效率低的问题,该研究提出一种基于机器视觉跟踪生长ROI茶垄间导航线提取算法。首先采用固定ROI(region of interest)方法,选取图像左下方区域为第一块ROI,在ROI内进行超绿指数灰度化,最大类方差法分割茶垄道路与背景,通过形态学操作对图像进行增强与降噪,使用最大连通域检测操作提取ROI内的坐标信息与特征点,根据ROI提取的坐标信息动态生成ROI,直到整个图像中所有茶垄道路信息提取完成,最后采用最小二乘法获取跨垄式采茶机底盘在垄间行驶的导航线。该方法经过连续帧测试,处理一帧1920×1080像素图像的平均时间为18 ms,该研究算法与人工提取导航线的航向角平均误差为0.405°,标准差为0.463°,可在一定杂草、落叶干扰的情况下完成导航角提取。
文摘为加速AprilTag检测,提出了一种基于改进YOLOv5s预提取RoI(region of interest)的AprilTag检测方法。改进YOLOv5s网络,在输入灰度图像的单通道模式下,分别采用Ghost Bottleneck和ConvNeXt Block替换主干网络和颈部网络的C3和瓶颈模块,提高模型的推理速度和泛化能力;通过亮度增强扩充数据集,提高模型鲁棒性。基于改进的YOLOv5网络进行AprilTag预识别,通过输出锚框划分RoI进行AprilTag检测,缩小图像处理范围,提高计算效率。实验结果表明,提出的AprilTag检测方法在1080P图像下FPS比传统AprilTag算法提高了77.42%以上。
基金the National Nature Science Foundation of China(31770437)。
文摘The cold regions are located in high latitudes and cold climates.The local excellent ornamental plant resources are relatively scarce.The plant species that are suitable for both ornamental and productive benefits of landscape of flower sea construction are also even fewer.Therefore,it is imperative to introduce and screen the plant resources suitable for cold regions to create the landscape of flower sea.The rape,an oilseed crop,was used as a research object in order to create a productive flower landscape with both ornamental and economic values in cold regions.Four rape flower varieties,Qingza No.5,7,9,and 11,were introduced from Qinghai Hufeng Agricultural Science and Technology Group Co.,Ltd.They were planted in the experimental practice base of Northeast Agricultural University in three batches.Development characteristics and seed yield of rape flowers on different sowing dates were studied.The fuzzy probability method was used to comprehensively evaluate the varieties.The results showed that the rape flowers grew well in Harbin City during the experimental sowing period,which could form a good landscape of flower sea and had a considerable rapeseed yield.It could be widely used in cold urban and rural areas,such as Harbin City.In view of the experimental results,the strategies of creating a productive landscape of rape flower sea were proposed and the economic benefits were analyzed.It could change the status quo of a uniform landscape of flower sea in cold regions,help the development of rural tourism,and promote local economic income.
基金Science and Technology Major Project of Tibetan Autonomous Region of China(XZ202201ZD0005G02)National Natural Science Foundation of China(42277353)Chengdu Science and Technology Project(2022-YF05-01162-SN)。
文摘[Background]As one of the most serious environmental issues in the world,soil erosion causes water pollution,reservoir siltation,soil productivity decline,thus threatens agricultural systems and even affects global climate.The benefits of ecological soil and water conservation measures(ESWCMs,such as micro basins tillage and contour tillage)are widely understood,including runoff and soil loss reducing to a certain extent when compared with traditional tillage.While few studies have focused on China’s different soil types and erosion characteristics.[Methods]We reviewed literature from Web of Science,Scopus,and China National Knowledge Infrastructure using terms like“Conservation practice”“Contour tillage”“Runoff”“Sediment”“Erosion”and“China”and retained literatures based on criteria such as natural or simulated precipitation,runoff or soil loss data,reported replications and statistics,recorded factors like location and slope,and at least two data pairs per group.Ultimately,49 literatures were selected to quantify the impacts on different ESWCMs and identify the slope and precipitation for the greatest runoff and sediment reduction by calculating the log response ratio(LRR).[Results]The three regions’soil and water conservation benefits varied due to the differences in climate,terrain,and soil properties:1)ESWCMs applied in the black soil region of Northeast China were the most effective in reducing runoff and soil loss(66.65%runoff and 75.83%sediment),followed by those applied in the purple soil region of Southwest China(39.98%runoff and 58.30%sediment)and loess soil region of Northwest China(16.36%runoff and 32.44%sediment).2)Micro basins tillage(MBT)(71.79%runoff and 87.03%sediment)no-tillage with mulch(NTM)(17.30%runoff and 32.51%sediment),collecting soil to form a ridge with no-till(CSNT)(55.78%runoff and 71.36%sediment reduction)were the most efficient soil and water conservation measures in controlling water erosion in the black soil of Northeast China,the loess soil region of Northwest China and the purple soil region of Southwest China,respectively.3)The slope gradients ranged from 0-3°,>3°-5°and>10°-15°(0-3°:97.09%;>3°-5°:74.62%;and>10°-15°:39.41%)caused the largest reduction of runoff in the black soil region of Northeast China,the loess soil region of Northwest China,and the purple soil region of Southwest China.Meanwhile,the effects of sediment reduction were the most obvious,ranging from 0-3°,>10°-15°,and>20°-25°(0-3°:89.32%;>10°-15°:75.94%;and>20°-25°:67.25%).4)The effect of ESWCMs under rainstorms was the most obvious in the black soil region of Northeast China.The effect on runoff reduction under light rain in the purple soil region of Southwest China was the most obvious,but it failed to pass the significance test in sediment reduction.[Conclusions]The results provided optimal conservation tillage measures for three regions,different slopes and different rainfalls,and provided data support for reducing regional soil and water loss in China.
基金Supported by the Department of Ecology and Environment of Heilongjiang Province(HST2022ST003)。
文摘This paper conducted a systematic survey and zoogeographical region analysis of the family Sphingidae in the Guokui Mountain,Heilongjiang Province.Collections were made from May 2023 to August 2024 using the light-trap method.A total of 14 species and 11 subspecies from 18 genera and three subfamilies were recorded.One species(Ambulyx tobii)and two subspecies(Ambulyx japonica koreana and Clanis undulosa undulosa)were new records for Heilongjiang Province.The study showed that the subfamily Smerinthinae had the most species(subspecies),while the subfamily Sphinginae had the fewest.Among the world's zoogeographical region,most species(subspecies)in the Guokui Mountain belonged to the palearctic region,with eight species and seven subspecies were also found in the oriental region.This indicated a close biogeographic connection between the two regions.Among the Chinese zoogeographical regions,the northeastern territory,northern territory and northwestern territory had the most abundant species(subspecies).It was also found that the distribution pattern types of hawkmoths in the Guokui Mountain were diverse,with the'northeastern territory-northern territory-northwestern territory'and'northeastern territory-northern territorynorthwestern territory-western plateau-southwestern territory-central territory-southeastern territory'types having the most species(subspecies).In addition,the Guokui Mountain hawkmoths were mostly distributed interregionally.The distribution patterns that contained the northeastern territory were the most numerous,followed by the northern territory.The rich diversity of the family Sphingidae in the Guokui Mountain was closely related to the unique climate,environment and vegetation types in the area.The results could help to improve the biodiversity database of Heilongjiang Province and researches on hawkmoths.
文摘针对机器视觉轴承内圈侧面复杂形状尺寸检测精度低的问题,提出根据检测目标建立小面积感兴趣区域(Region of Interest,ROI)的自适应选取方法和基于Zernike矩的ROI亚像素级边缘提取方法,大幅提升了轴承内圈尺寸的检测精度。首先分别拍摄轴承内圈左侧与右侧轮廓图像,对图像进行预处理。在此基础上,通过角点检测融合像素扫描的方法实现自适应ROI选取,解决了因轴承内圈移动引起的小面积ROI边缘误判问题;使用Canny算子提取ROI的像素级边缘,再用改进的Zernike矩算法得到亚像素级边缘。最后,分别对ROI中提取的边缘进行最小二乘圆拟合和直线拟合,根据像素当量与视场间隔将图像中各尺寸转换为轴承内圈实际尺寸。实验结果表明:所提方法测量的标准不确定度低于0.005 mm,满足轴承尺寸高精度检测的要求,对于实现轴承检测的自动化有实际意义。
基金State Natural Scientific Foundation (49734150) and National High Performance Computation Foundation.
文摘We assembled approximately 328 seismic records. The data set was from 4 digitally recording long-period and broadband stations of CDSN. We carried out the inversion based on the partitioned waveform inversion (PWI). It partitions the large-scale optimization problem into a number of independent small-scale problems. We adopted surface waveform inversion with an equal block (2((2() discretization in order to acquire the images of shear velocity structure at different depths (from surface to 430 km) in the crust and upper-mantle. The resolution of all these anomalies has been established with (check-board( resolution tests. These results show significant difference in velocity, lithosphere and asthenosphere structure between South China Sea and its adjacent regions.
基金Project(2014BAG05B04)supported by the National Science and Technology Support Program,ChinaProject(51378006)supported by the National Natural Science Foundation of ChinaProject(2242015R30027)supported by the Excellent Young Teacher Program of Southeast University,China
文摘This study investigated the temperature field and thawing depth of wide embankment for expressway in permafrost regions based on numerical analysis by using finite element method(FEM).According to specific embankment section of Qinghai-Tibet highway,computational region for numerical analysis was defined.And numerical model was developed through FEM software named as ABAQUS and was verified by field observed data.The effects by width and height of embankment on the thermal regime of computational region were analyzed based on FEM modeling.Numerical analysis showed that embankment construction has serious disturbance on the thermal stability of ground permafrost showing as annual average ground temperature and the maximum thawing depth keeps increasing with service time increasing.And larger embankment width leads to poorer thermal stability and more serious uneven temperature field of embankment.Raising embankment height can improve the thermal stability; however,the improvement is restricted for wide embankment and it cannot change the degradation trend of thermal stability with service life increasing.Thus,to construct expressway with wide embankment in permafrost regions of Qinghai-Tibet Plateau,effective measures need to be considered to improve the thermal stability of underlying permafrost.
基金Project(2018-MSI-018) supported by the Key Science and Technology Project of the Ministry of Transport of ChinaProject(NJ-2018-28) supported by the Construction Science and Technology of the Department of Transport of Inner Mongolia Autonomous Region of China+2 种基金Project(2019MS05029) supported by the Natural Science Fund Project of Inner Mongolia Autonomous Region of ChinaProject(2020MS05077) supported by the Natural Science Fund Project of Inner Mongolia Autonomous Region of ChinaProject(NJ-2020-05) supported by the Research on Complete Survey Technology of Highway Road Area in High-latitude Permafrost Region, China。
文摘To reveal the influencing factors and changing rules for the hydrothermal interaction process of highway subgrade, the field measurements of Shiwei-Labudalin Highway in Inner Mongolia, China was conducted for 3 years, based on which the freezing-thawing rules and water content changing characteristics were analyzed. The main results show the subgrade presents a frequent freezing-thawing alternation, and the water content of subgrade exhibits an obvious seasonal alternation. The subbase has the maximum water content, while the base has the minimum water content. The change of water flux is concentrated in the thawing period and consistent with the change of temperature gradient. The subbase layer has the most active water flux due to the heat absorption and impermeability of pavement that easily causes the water accumulation in this layer. Therefore, the prevention and treatment for the freezing-thawing disease should be started from heat insulation and water resistance.
基金Project(50838009) supported by the National Natural Science Foundation of ChinaProject(2006BAJ01A05) supported by the National Key Technologies R&D Program of ChinaProject(CSTC,2008AB7110) supported by Key Technologies R & D Program of Chongqing City,China
文摘The current ventilation condition of the hot and humid regions was analyzed through on-site investigation. It is found that residents in this region expect to improve indoor thermal environment through natural ventilation as much as possible. Then,it comes to a conclusion by the field test that natural ventilation has certain practical effect on improving indoor thermal environment. CFD simulation software is employed to verify the test result. Based on PMV modified model,and according to norms,geography and climate combined with the measured and simulated results,the application of the time and effectiveness of natural ventilation in hot and humid region were analyzed,to some extent,providing a basis for reducing the air-conditioner's runtime with natural ventilation.
文摘We have conducted some studies on 3 ground cherry cultivars'Artaskaja'.'Bushkaja'and'Maksmorfikaja'introduced from Russia.The results indicated that these cultivars could survive temperature -40℃ during severe winter in Harbin,China and had high drought and disease resistance,the average weight of each fruit reached 2.78g,the contents of Vc and soluble solid exceeded 30mg/100g and 12%,respectively.Not only does the fruits suit for fresh market,but also for processing.Ground cherry is a promising new fruit crop in cold region.
基金supported by the New Century Excellent Talents of China (NCET-05-0866)
文摘A novel multi-view 3D face registration method based on principal axis analysis and labeled regions orientation called local orientation registration is proposed.The pre-registration is achieved by transforming the multi-pose models to the standard frontal model＇s reference frame using the principal axis analysis algorithm.Some significant feature regions, such as inner and outer canthus, nose tip vertices, are then located by using geometrical distribution characteristics.These regions are subsequently employed to compute the conversion parameters using the improved iterative closest point algorithm, and the optimal parameters are applied to complete the final registration.Experimental results implemented on the proper database demonstrate that the proposed method significantly outperforms others by achieving 1.249 and 1.910 mean root-mean-square measure with slight and large view variation models, respectively.
文摘Ⅰ. An analysis of the development trend of the economy in the north,middle aud south coastal regions or China since China began to implementreform and open
基金support from National Heart Lung and Blood Institute Grants P50-HL56985 and R01-HL61794
文摘Introduction Atherosclerosis is a potentially life-threatening disease of large arteries that is strongly associated with systemic risk factors such as hypercholesterolemia,hypertension,smoking,and diabetes. However,atherosclerosis develops as a
基金This research program was financially sponsored by the National Key Research and Development Plan(2016YFD0100306)the National Natural Science Foundation of China(31671745,31530053).
文摘Background:Segregation distortion(SD)is a common phenomenon among stable or segregating populations,and the principle behind it still puzzles many researchers.The F2:3 progenies developed from the wild cotton species of the D genomes were used to investigate the possible plant transcription factors within the segregation distortion regions(SDRs).A consensus map was developed between two maps from the four D genomes,map A derived from F2:3 progenies of Gossypium klotzschianum and G.davidsonii while Map B from G.thurberi and G.trilobum F2:3 generations.In each map,188 individual plants were used.Results:The consensus linkage map had 1492 markers across the 13 linkage groups with a map size of 1467.445 cM and an average marker distance of 1.0370 cM.Chromosome D502 had the highest percentage of SD with 58.6%,followed by Chromosome D507 with 47.9%.Six thousand and thirty-eight genes were mined within the SDRs on chromosome D502 and D507 of the consensus map.Within chromosome D502 and D507,2308 and 3730 genes were mined,respectively,and were found to belong to 1117 gourp out of which 622 groups were common across the two chromosomes.Moreover,genes within the top 9 groups related to plant resistance genes(R genes),whereas 188 genes encoding protein kinase domain(PF00069)comprised the largest group.Further analysis of the dominant gene group revealed that 287 miRNAs were found to target various genes,such as the gra-miR398,gramiR5207,miR164a,miR164b,miR164c among others,which have been found to target top-ranked stress-responsive transcription factors such as NAC genes.Moreover,some of the stress-responsive cis-regulatory elements were also detected.Furthermore,RNA profiling of the genes from the dominant family showed that higher numbers of genes were highly upregulated under salt and osmotic stress conditions,and also they were highly expressed at different stages of fiber development.Conclusion:The results indicated the critical role of the SDRs in the evolution of the key regulatory genes in plants.
基金This work was supported by the National Key Research and Development Program of China(2022YFC3003101)the Fundamental Research Funds for the Central Universities(WK2320000050)the Science and Technology Program of State Grid Anhui Electric Power Co.,Ltd.(521205220001).
文摘Forest fire accidents caused by distribution line faults occur frequently,resulting in heavy impacts on people’s safety and social and economic development.Currently,there are few risk assessments for forest fires induced by over-head distribution lines,and existing assessment methods may have difficulties in data acquisition.On this basis,a novel as-sessment framework based on an analytic hierarchy process,a Bayesian network and a Fussel-Vesely importance metric is proposed in this paper.The framework combines field research and historical operation and maintenance data to assess the regional-scale risk of forest fires induced by overhead distribution lines to derive the probability of forest fires and to identify high-risk lines and key hazard events in the assessment region.Finally,taking the southern Anhui region as an ex-ample,the annual fire probability of forest fires induced by overhead distribution lines in the southern Anhui region is 5.88%,and rectification measures are proposed.This study provides management with a complete assessment framework that optimizes the difficulty of data collection and allows for additional targeted corrective measures to be proposed for the entire region and route on the basis of the assessment results.
