This study was performed to observe the effects of water on photosynthesis and water-related physiology in dominant shrubs in shell sand habitats.Four-year-old Periploca sepium seedlings were used as model species.A g...This study was performed to observe the effects of water on photosynthesis and water-related physiology in dominant shrubs in shell sand habitats.Four-year-old Periploca sepium seedlings were used as model species.A gradient of 12 water levels was established by artificially supplying the shell sand with water up to saturation and then allowing natural evapotranspiration to occur.The photo synthetic,chlorophyll fluorescence and stem sap flow parameters of P.sepium were measured under a range of water conditions.The different soil water conditions were classified according to the responses of these parameters.(1)With the increase in the relative water content(RWC)of the shell sand,the parameters of leaf photosynthesis,chlorophyll fluorescence and water-related physiology in P.sepium showed significant critical responses.The net photo synthetic rate(Pn),transpiration rate(Tr),instantaneous water use efficiency(WUE),potential water use efficiency(WUEi),maximum photochemical efficiency(Fv/Fm),actual photochemical efficiency(ΦPSII)and daily accumulation of stem sap flow all increased first and then decreased with increasing RWC,but the corresponding water conditions associated with their maximum values were not the same.An RWC of 69.40%was determined to be the optimal water condition for photosynthesis and water-related physiological activity in P.sepium.At an RWC of 36.61%,the mechanism of photosynthetic inhibition in P.sepium changed from stomatal limitation to nonstomatal limitation;this was also the minimum water requirement for maintaining normal photo synthetic processes.An RWC of 50.27%resulted in the highest WUE in P.sepium,indicating that moderate drought stress increased WUE.(2)Based on the quantitative relationship between the photo synthetic parameters of P.sepium and the shell sand water gradient,the soil water availability was classified into 6 water grades.The RWC range for maintaining strong photosynthesis and high WUE in P.sepium was 63.22-69.98%.(3)Gas exchange in P.sepium was inhibited under drought and waterlogging stresses.Under these conditions,the photosynthetic electron transport chain was blocked,and the dissipation of light energy as heat increased,which ultimately led to a decline in photo synthetic productivity;moreover,transpiration and dissipation were aggravated,and water transmission and utilization processes in P.sepium were hindered.A significant negative feedback regulation mechanism in the photosynthetic and water-related physiological processes of P.sepium was observed;this mechanism allowed P.sepium growing in shell sand to be highly adaptable to water stress.展开更多
The results of a study on the key technology of using shell sand, a kind of sea sand, as backfill for sea reclamation are described briefly. Iaboratory tests show that the physical and mechanical properties of shell s...The results of a study on the key technology of using shell sand, a kind of sea sand, as backfill for sea reclamation are described briefly. Iaboratory tests show that the physical and mechanical properties of shell sand are as good as normal quartz sand. Based on the chemical test and durability test of shell sand it could be concluded that the influence of corrosion of shell sand by acid rain and sea water might be ignored in the evaluation of the safety and durability of the engineering project. The results of field improvement tests show that the bearing capacity of shell sand backfill foundation is more than 200 kPa after vibmflotation improvement or dynamic compaction improvement. The shell sand is a good backfill material for sea reclamation.展开更多
Oyster shell powder was used as the admixture of ordinary portland cement.The effects of different addition amounts and grinding ways on the strength and stability of cement mortar were discussed and proper addition a...Oyster shell powder was used as the admixture of ordinary portland cement.The effects of different addition amounts and grinding ways on the strength and stability of cement mortar were discussed and proper addition amount of oyster shell powder was determined.The structure and property changes of cementing samples with different oyster shell powder contents were tested by XRD and SEM means.The results revealed that compressive and rupture strengths of the sample with 10% oyster shell powder was close to those of the original one without addition.Stability experiment showed that the sample prepared by pat method had smooth surface without crack and significant expansion or shrinkage after pre-curing and boiling,which indicated that cementing material dosed with oyster shell powder had fine stability.XRD and SEM observation showed that oyster shell independently exists in the cementing material.展开更多
为解决现有分割网络中小面积区域像素表达能力差、区域上下文信息类别被混淆、区域分布不规则等导致的鸡蛋沙壳区域分割性能不佳的问题,本文以此类鸡蛋图像为研究对象,提出了一种基于上下文信息的鸡蛋沙壳区域实例分割方法(Global-Local...为解决现有分割网络中小面积区域像素表达能力差、区域上下文信息类别被混淆、区域分布不规则等导致的鸡蛋沙壳区域分割性能不佳的问题,本文以此类鸡蛋图像为研究对象,提出了一种基于上下文信息的鸡蛋沙壳区域实例分割方法(Global-Local Contexts based Instance Segmentation Model for Egg Sand-shell Region,GL-ISR)。首先,对沙壳区域特征进行全局(Global Context Information Module,GCIM)和局部(Local Context Information Module,LCIM)上下文信息建模,前者利用金字塔池化对特征图进行多尺度上下文加权聚合以收集不同像素区域的上下文信息,后者则通过构建Label Map与Label Prior Layer监督上下文依赖类别以区分上下文信息来源;其次,将两部分上下文与原特征图进行聚合,以增强沙壳区域特征表达能力,从而提高模型的分割性能。为验证所提模型的有效性,本文在包含3类区域、7160幅沙壳蛋图像的自标注数据集上进行了实验。结果表明,GL-ISR在IoU阈值为0.5和0.75情况下分别取得70.02%和44.16%的最优mAP值,在IoU阈值介于0.5至0.95之间取得最优平均mAP值48.22%,显著优于其他模型。具体地,GL-ISR的在光滑区域、面状沙壳和点状沙壳上分别取得85.16%、46.39%和41.17%的像素精准度,即使在分割难度较大的点状沙壳区域上,该模型的像素精准度仍保持在40%以上。因此,上述实验结果表明了GL-ISR模型在鸡蛋沙壳区域分割方面的有效性,可为沙壳蛋品质改良提供理论基础。展开更多
基金supported by the Forestry Science and Technology Innovation Project of Shandong Province(No.2019LY006)the National Natural Science Foundation of China(No.31770761)+1 种基金Open Research Fund Program of Shandong Key Laboratory of Eco-Environmental Science for Yellow River Delta(Binzhou University)(No.2020KFJJ03)the Taishan Scholars Program of Shandong ProvincemChina(No.TSQN201909152)。
文摘This study was performed to observe the effects of water on photosynthesis and water-related physiology in dominant shrubs in shell sand habitats.Four-year-old Periploca sepium seedlings were used as model species.A gradient of 12 water levels was established by artificially supplying the shell sand with water up to saturation and then allowing natural evapotranspiration to occur.The photo synthetic,chlorophyll fluorescence and stem sap flow parameters of P.sepium were measured under a range of water conditions.The different soil water conditions were classified according to the responses of these parameters.(1)With the increase in the relative water content(RWC)of the shell sand,the parameters of leaf photosynthesis,chlorophyll fluorescence and water-related physiology in P.sepium showed significant critical responses.The net photo synthetic rate(Pn),transpiration rate(Tr),instantaneous water use efficiency(WUE),potential water use efficiency(WUEi),maximum photochemical efficiency(Fv/Fm),actual photochemical efficiency(ΦPSII)and daily accumulation of stem sap flow all increased first and then decreased with increasing RWC,but the corresponding water conditions associated with their maximum values were not the same.An RWC of 69.40%was determined to be the optimal water condition for photosynthesis and water-related physiological activity in P.sepium.At an RWC of 36.61%,the mechanism of photosynthetic inhibition in P.sepium changed from stomatal limitation to nonstomatal limitation;this was also the minimum water requirement for maintaining normal photo synthetic processes.An RWC of 50.27%resulted in the highest WUE in P.sepium,indicating that moderate drought stress increased WUE.(2)Based on the quantitative relationship between the photo synthetic parameters of P.sepium and the shell sand water gradient,the soil water availability was classified into 6 water grades.The RWC range for maintaining strong photosynthesis and high WUE in P.sepium was 63.22-69.98%.(3)Gas exchange in P.sepium was inhibited under drought and waterlogging stresses.Under these conditions,the photosynthetic electron transport chain was blocked,and the dissipation of light energy as heat increased,which ultimately led to a decline in photo synthetic productivity;moreover,transpiration and dissipation were aggravated,and water transmission and utilization processes in P.sepium were hindered.A significant negative feedback regulation mechanism in the photosynthetic and water-related physiological processes of P.sepium was observed;this mechanism allowed P.sepium growing in shell sand to be highly adaptable to water stress.
基金This work was financially supported by CNOOC(Grant No.Z2004SLFJ-TS26)
文摘The results of a study on the key technology of using shell sand, a kind of sea sand, as backfill for sea reclamation are described briefly. Iaboratory tests show that the physical and mechanical properties of shell sand are as good as normal quartz sand. Based on the chemical test and durability test of shell sand it could be concluded that the influence of corrosion of shell sand by acid rain and sea water might be ignored in the evaluation of the safety and durability of the engineering project. The results of field improvement tests show that the bearing capacity of shell sand backfill foundation is more than 200 kPa after vibmflotation improvement or dynamic compaction improvement. The shell sand is a good backfill material for sea reclamation.
基金Supported by the National Natural Science Foundation of China (No. 51102047)Fujian Provincial of Science and Technology (2011Y0037)Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry SRF for ROCS,SEM
文摘Oyster shell powder was used as the admixture of ordinary portland cement.The effects of different addition amounts and grinding ways on the strength and stability of cement mortar were discussed and proper addition amount of oyster shell powder was determined.The structure and property changes of cementing samples with different oyster shell powder contents were tested by XRD and SEM means.The results revealed that compressive and rupture strengths of the sample with 10% oyster shell powder was close to those of the original one without addition.Stability experiment showed that the sample prepared by pat method had smooth surface without crack and significant expansion or shrinkage after pre-curing and boiling,which indicated that cementing material dosed with oyster shell powder had fine stability.XRD and SEM observation showed that oyster shell independently exists in the cementing material.
文摘为解决现有分割网络中小面积区域像素表达能力差、区域上下文信息类别被混淆、区域分布不规则等导致的鸡蛋沙壳区域分割性能不佳的问题,本文以此类鸡蛋图像为研究对象,提出了一种基于上下文信息的鸡蛋沙壳区域实例分割方法(Global-Local Contexts based Instance Segmentation Model for Egg Sand-shell Region,GL-ISR)。首先,对沙壳区域特征进行全局(Global Context Information Module,GCIM)和局部(Local Context Information Module,LCIM)上下文信息建模,前者利用金字塔池化对特征图进行多尺度上下文加权聚合以收集不同像素区域的上下文信息,后者则通过构建Label Map与Label Prior Layer监督上下文依赖类别以区分上下文信息来源;其次,将两部分上下文与原特征图进行聚合,以增强沙壳区域特征表达能力,从而提高模型的分割性能。为验证所提模型的有效性,本文在包含3类区域、7160幅沙壳蛋图像的自标注数据集上进行了实验。结果表明,GL-ISR在IoU阈值为0.5和0.75情况下分别取得70.02%和44.16%的最优mAP值,在IoU阈值介于0.5至0.95之间取得最优平均mAP值48.22%,显著优于其他模型。具体地,GL-ISR的在光滑区域、面状沙壳和点状沙壳上分别取得85.16%、46.39%和41.17%的像素精准度,即使在分割难度较大的点状沙壳区域上,该模型的像素精准度仍保持在40%以上。因此,上述实验结果表明了GL-ISR模型在鸡蛋沙壳区域分割方面的有效性,可为沙壳蛋品质改良提供理论基础。
