We established a model for investigating polycrystalline silicon（poly-Si） thin film transistors（TFTs）.The effect of grain boundaries（GBs） on the transfer characteristics of TFT was analyzed by considering the nu...We established a model for investigating polycrystalline silicon（poly-Si） thin film transistors（TFTs）.The effect of grain boundaries（GBs） on the transfer characteristics of TFT was analyzed by considering the number and the width of grain boundaries in the channel region,and the dominant transport mechanism of carrier across grain boundaries was subsequently determined.It is shown that the thermionic emission（TE） is dominant in the subthreshold operating region of TFT regardless of the number and the width of grain boundary.To a poly-Si TFT model with a 1 nm-width grain boundary,in the linear region,thermionic emission is similar to that of tunneling（TU）,however,with increasing grain boundary width and number,tunneling becomes dominant.展开更多
To reveal the sediment transporting mechanism between the abandoned Huanghe River （Yellow River） Delta and radial sand ridges, “End Member” Model and grain size trend analysis have been employed to separate the “...To reveal the sediment transporting mechanism between the abandoned Huanghe River （Yellow River） Delta and radial sand ridges, “End Member” Model and grain size trend analysis have been employed to separate the “dynamic populations” in the surficial sediment particle spectra and to determine the possible sediment transporting pathway. The results reveal four “dynamic subpopulations”（EM1 to EM4） and two reverse sediment transporting directions： a northward transport tend from the radial sand ridges to mud patch, and a southward transport trend in deep water area outside the mud patch. Combined with the published hydrodynamic information, the transporting mechanism of dynamic populations has been discussed, and the main conclusion is that the transporting of finer subpopulations EM1 and EM2 is controlled by the “anticlockwise residual current circulation” forming during tidal cycle, which favor a northward transporting trend and the forming of mud patch on the north of radial sand ridges, while the transporting of coarser EM3 is mainly controlled by wind driven drift in winter, which favors a southward transporting direction.展开更多
Sediment grain size in the deltaic environment of the Luanhe River(LR),Liaoning,China,contains sediment transport pathway information useful in elucidating the shoreline change and fluvialmarine interaction.In this st...Sediment grain size in the deltaic environment of the Luanhe River(LR),Liaoning,China,contains sediment transport pathway information useful in elucidating the shoreline change and fluvialmarine interaction.In this study,we utilized numerical partitioning of the sedimentary components and geostatistical grain size trend analysis(GSTA)to define the sediment transport pattern in the Luanhe River delta(LRD)and interpolated the sediment transport pattern using content changes of end numbers(EM).EM1(the mean grain size 7.12Ф,fine silt),EM2(2.37Ф,fine sand),and EM3(1.27Ф,medium sand)components were identified by the numerical partitioning by GSTA.Kriging interpolation method was used to interpolate the parameters of the grain size for the regular grid,and the interpolation radius was 0.015 decimal degree.We chose 0.09 decimal degree as the characteristic distance for GSTA in the semivariogram model using the geostatistical method.The FB(-)case(finer,better sorted and more negatively skewed)was adopted in GSTA for its satisfaction in the Global Moran’s I test.The result of the GSTA shows that the sediments in the south barriers(SBs)were transported to the southwest of the study area.The sediments in the north,in the SE direction of sediment transport trend from the river mouth,indicated that the sediments in the north of the study area were transported from the LR to the northern beaches,and to the south and east of the study area.The sediment transport trend that simplified by GSTA as the FB(-)case was approved by the content changes of sedimentary components(i.e.EM1,EM2,and EM3).In addition,the turbulent jet diffusion pattern indicated that the coarse sediments(EM3)were delivered by LR during the flood season,and the EM2 and EM1 were from wave and tide,respectively.展开更多
Sediment transport in estuarine systems has been of increasing interest for scientists during the past few decades. However, the mechanisms for sediment redistribution remain unclear. We characterized in detail sedime...Sediment transport in estuarine systems has been of increasing interest for scientists during the past few decades. However, the mechanisms for sediment redistribution remain unclear. We characterized in detail sediment transport in the Xiaoqing River estuary using the mathematical Weibull function to partition grain-size components of surface sediments in the southwestern Laizhou Bay, Northeast China. Four partitioned components: finer than 4,4.6-12.5, 23.4-63.3, and 67.1-132.6 μm were interpreted in terms of hydrodynamic conditions. During sediment transport, silt grains were suspended and moved seaward from three depositional centers, whereas fine-grained sands moved generally landward. Overall, sediments are transported clockwise in a generally NNE direction near shore and then turn eastward offshore. The mathematical partitioning method showed a great potential for future estuarine environmental studies.展开更多
Surface sediments from the Changjiang River （Yangtze River） Estuary, Hangzhou Bay, and their adjacent waters were analyzed for their grain size distribution, organic carbon （OC） concentration, and stable carbon is...Surface sediments from the Changjiang River （Yangtze River） Estuary, Hangzhou Bay, and their adjacent waters were analyzed for their grain size distribution, organic carbon （OC） concentration, and stable carbon isotope composition （δ13C）. Based on this analysis, about 36 surface sediment samples were selected from various environments and separated into sand （〉0.250 ram, 0.125-0.250 ram, 0.063-0.125 mm） and silt （0.025-0.063 mm） fractions by wet-sieving fractionation methods, and further into silt- （0.004-0.025 mm） and clay-sized （〈0.004 mm） fractions by centrifugal fractionation. Sediments of six grain size categories were analyzed for their OC and 613C contents to explore the grain size composition and transport paths of sedimentary OC in the study area. From fine to coarse fractions, the OC content was 1.18%, 0.51%, 0.46%, 0.42%, 0.99%, and 0.48%, respectively, while the δ13C was -21.64‰, -22.03‰, -22.52‰, -22.46‰, -22.36‰, and -22.28%0, respectively. In each size category, the OC contribution was 42.96%, 26.06%, 9.82%, 5.75%, 7.09%, and 8.33%, respectively. The OC content in clay and fine silt fractions （〈0.025 ram） was about 69.02%. High OC concentrations were mainly found in offshore modern sediments in the northeast of the Changjiang River Estuary, in modern sediments in the lower estuary of the Changjiang River and Hangzhou Bay, and in Cyclonic Eddy modern sediments to the southwest of the Cheju Island. Integrating the distribution of terrestrial OC content of each grain size category with the δ13C of the bulk sediment indicated that the terrestrial organic material in the Changjiang River Estuary was transported seaward and dispersed to the Cyclonic Eddy modern sediments to the southwest of the Cheju Island via two pathways： one was a result of the Changjiang River Diluted Water （CDW） northeastward extending branch driven by the North Jiangsu Coastal Current and the Yellow Sea Coastal Current, while the other one was the result of the CDW southward extending branch driven by the Taiwan Warm Current.展开更多
A current-turbidity monitoring system (CTMS) was deployed on the intertidal flat at Wanggang, northern Jiangsu during October 16-17, 2000, to measure the tidal current speeds and seawater turbidities at 5 levels above...A current-turbidity monitoring system (CTMS) was deployed on the intertidal flat at Wanggang, northern Jiangsu during October 16-17, 2000, to measure the tidal current speeds and seawater turbidities at 5 levels above the seabed. Based upon the logarithmic-profile equation, the boundary layer parameters, i.e., u, z0 and C60, were obtained for 247 tidal flow velocity profiles. Around 90% of the profiles were logarithmic according to the critical correlation coefficient. Internal consistency analysis shows that these parameters derived by different methods are consistent with each other. In addition, the height of the bedforms observed is close to the seabed roughness lengths calculated from the velocity profiles, indicating that the boundary layer parameters obtained can reveal the conditions at the sediment-water interface on the intertidal flats. Suspended sediment concentrations were obtained from the 5 CTMS turbidity meters using laboratory and in-situ calibrations. The results show that the in-situ calibrated SSCs have a much higher accuracy than the laboratory calibrated ones. Calculation of suspended sediment fluxes on the intertidal flats, with a magnitude of 104 kg/m per spring tidal cycle, indicates that suspended sediment moves towards the northwest, which is reversal to the transport pattern controlled by the southward Northern Jiangsu Coastal Current in the sub-tidal zone and adjacent shallow waters.展开更多
High-resolution seismic profiles and surface samples were studied in detail in order to determine the structures, provenance, and dynamic mechanisms of a fine-grained deposit in the southeast coastal area of the Liaod...High-resolution seismic profiles and surface samples were studied in detail in order to determine the structures, provenance, and dynamic mechanisms of a fine-grained deposit in the southeast coastal area of the Liaodong Peninsula, China. Results indicate that there is a prominent fine-grained deposit distributed alongshore up to 14 m thick, which thins out to less than 2 m in both seaward and landward directions, forming an Ω-shaped pattern of cross-section. The deposit is 180-300 km away from the Yalu River mouth and extends along the southeast coast of the Liaodong Peninsula between the northeast of Dalian Bay and southwest of the Changshan Islands, in water depths of 20-40 m. The deposit, which is mainly derived from the Yalu River, represents a Holocene Highstand System Tract sequence formed since the highest sea level around 7.0 ka. The Yalu River-derived sediments were redeposited in the area off the southeast coast of the Liaodong Peninsula after resuspension and transportation by the Liaonan Coastal Current.展开更多
Spatial changes in grain size parameters (i.e. grain size trends) contain information on sediment transport patterns. An analytical procedure has been proposed to transform the grain size trends into an image of trend...Spatial changes in grain size parameters (i.e. grain size trends) contain information on sediment transport patterns. An analytical procedure has been proposed to transform the grain size trends into an image of trend vectors, which may represent net sediment transport pathways. A fundamental assumption for such an approach is that the frequency of occurrence of the trend adopted is much higher in the transport direction, than in any of other directions. Preliminary studies show agreement between this assumption and observations. However, further investigations into the physical processes and mechanisms for the formation of grain size trends are required to improve the technique, including flume experiments and numerical modeling. Moreover, attention should be paid to the trends associated with fine grained sediment, for the method of grain size trend analysis is so far designed for coarse grained material only. The processes of flocculation during settling and the wash load property must be considered. Appropriate interpretation of grain size data will improve our understanding of the physics of granular materials.展开更多
Tidal cycle measurements of tidal currents, salinity and water tempe rature, and suspended sediment concentrations were measured at four stations, to gether with surveys along two profiles short core collection within...Tidal cycle measurements of tidal currents, salinity and water tempe rature, and suspended sediment concentrations were measured at four stations, to gether with surveys along two profiles short core collection within the Yalu Riv er estuary. Grain size analysis of the three core sediment showed that: 1) the s ediment from B1 to B3 became finer, worse sorting and positively skewed; 2) the diversification of matter origin became more and more evident from east to west; 3) the sediments over the region were of the same origin, as indicated by their similar colors and grain sizes. The data indicated that stratification occurred in the flood season, from upstream to downstream, and a salt wedge was formed. The water column was well mixed, but the longitudinal gradient of the salinity w as larger on spring tide. The results also showed that the dominating mechanism of suspended sediment transport in the Yalu River estuary was T1, T2, T3 and T5. The non-tidal steady advection transport was restricted by the net transport o f suspended sediment induced by mass Stoked drift directed to landwards, then th e net sediment transport rate were decreased and the turbidity maxima was also f avored to forming and extending.展开更多
The containerized shipment of freight continues to grow rapidly. This development can be traced to a transformation of bulk and break-bulk service to containerization. Demand has been driven by opportunities to broade...The containerized shipment of freight continues to grow rapidly. This development can be traced to a transformation of bulk and break-bulk service to containerization. Demand has been driven by opportunities to broaden logistical options as well as advantageous freight rates. Logisticians and policy makers are unsure how much more bulk traffic can be converted to containerization, but the trends are evident. Of particular interest is grain. Bulk grain handlers have successfully resisted the conversion of grain shipping to containerization, except on the North American-Asian traffic lanes and the Australian-Asian traffic lanes where growth has been significant. This paper reviews the theoretical case for grain containerization from a logistics perspective, followed by an examination of the current trends in the United States and Canada. Subsequently, the analysis considers the restrictions and resistance to the conversion of grain from bulk shipping to containerization.展开更多
The German Armed Forces University in Munich has conducted experiments in a laboratory flume to determine the influence of roundness on bed load transport.The investigations were assigned by the German Federal Institu...The German Armed Forces University in Munich has conducted experiments in a laboratory flume to determine the influence of roundness on bed load transport.The investigations were assigned by the German Federal Institute of Hydrology (BIG),with a focus on incipient motion,transport velocity and the depth of mixing into the riverbed. The results of the experiments show that the transport velocity of angular graim is lower and the critical shear stress for incipient motion is slightly higher than of well-ro...展开更多
基金Funded by the National Natural Science Foundation of China(Nos.51202063 and 51177003)Hubei Provincial Department of Education(No.Q20111009)
文摘We established a model for investigating polycrystalline silicon（poly-Si） thin film transistors（TFTs）.The effect of grain boundaries（GBs） on the transfer characteristics of TFT was analyzed by considering the number and the width of grain boundaries in the channel region,and the dominant transport mechanism of carrier across grain boundaries was subsequently determined.It is shown that the thermionic emission（TE） is dominant in the subthreshold operating region of TFT regardless of the number and the width of grain boundary.To a poly-Si TFT model with a 1 nm-width grain boundary,in the linear region,thermionic emission is similar to that of tunneling（TU）,however,with increasing grain boundary width and number,tunneling becomes dominant.
文摘To reveal the sediment transporting mechanism between the abandoned Huanghe River （Yellow River） Delta and radial sand ridges, “End Member” Model and grain size trend analysis have been employed to separate the “dynamic populations” in the surficial sediment particle spectra and to determine the possible sediment transporting pathway. The results reveal four “dynamic subpopulations”（EM1 to EM4） and two reverse sediment transporting directions： a northward transport tend from the radial sand ridges to mud patch, and a southward transport trend in deep water area outside the mud patch. Combined with the published hydrodynamic information, the transporting mechanism of dynamic populations has been discussed, and the main conclusion is that the transporting of finer subpopulations EM1 and EM2 is controlled by the “anticlockwise residual current circulation” forming during tidal cycle, which favor a northward transporting trend and the forming of mud patch on the north of radial sand ridges, while the transporting of coarser EM3 is mainly controlled by wind driven drift in winter, which favors a southward transporting direction.
基金Supported by the National Science Foundation of China and Shandong Provincial Government(No.U1706214)the Basic Scientific Fund for National Public Research Institutes of China(No.2016Q06)
文摘Sediment grain size in the deltaic environment of the Luanhe River(LR),Liaoning,China,contains sediment transport pathway information useful in elucidating the shoreline change and fluvialmarine interaction.In this study,we utilized numerical partitioning of the sedimentary components and geostatistical grain size trend analysis(GSTA)to define the sediment transport pattern in the Luanhe River delta(LRD)and interpolated the sediment transport pattern using content changes of end numbers(EM).EM1(the mean grain size 7.12Ф,fine silt),EM2(2.37Ф,fine sand),and EM3(1.27Ф,medium sand)components were identified by the numerical partitioning by GSTA.Kriging interpolation method was used to interpolate the parameters of the grain size for the regular grid,and the interpolation radius was 0.015 decimal degree.We chose 0.09 decimal degree as the characteristic distance for GSTA in the semivariogram model using the geostatistical method.The FB(-)case(finer,better sorted and more negatively skewed)was adopted in GSTA for its satisfaction in the Global Moran’s I test.The result of the GSTA shows that the sediments in the south barriers(SBs)were transported to the southwest of the study area.The sediments in the north,in the SE direction of sediment transport trend from the river mouth,indicated that the sediments in the north of the study area were transported from the LR to the northern beaches,and to the south and east of the study area.The sediment transport trend that simplified by GSTA as the FB(-)case was approved by the content changes of sedimentary components(i.e.EM1,EM2,and EM3).In addition,the turbulent jet diffusion pattern indicated that the coarse sediments(EM3)were delivered by LR during the flood season,and the EM2 and EM1 were from wave and tide,respectively.
基金Supported by the China Postdoctoral Science Foundation (No.2012M520369)the National Natural Science Foundation of China (Nos.40906047,41076031,40925012)+1 种基金the State Oceanic Research Project for Public Benefit of China (No.201105020)the National Basic Research Program of China (973 Program) (Nos.2010CB951201,2012CB821900)
文摘Sediment transport in estuarine systems has been of increasing interest for scientists during the past few decades. However, the mechanisms for sediment redistribution remain unclear. We characterized in detail sediment transport in the Xiaoqing River estuary using the mathematical Weibull function to partition grain-size components of surface sediments in the southwestern Laizhou Bay, Northeast China. Four partitioned components: finer than 4,4.6-12.5, 23.4-63.3, and 67.1-132.6 μm were interpreted in terms of hydrodynamic conditions. During sediment transport, silt grains were suspended and moved seaward from three depositional centers, whereas fine-grained sands moved generally landward. Overall, sediments are transported clockwise in a generally NNE direction near shore and then turn eastward offshore. The mathematical partitioning method showed a great potential for future estuarine environmental studies.
基金The National Basic Research Program(973 Program)of China under contract No.2010CB428903the National Natural Science Foundation of China under contract Nos 41106050,41203085 and 41076036+1 种基金the Public Welfare Industry Research Specific Funding of China under contract Nos 201105014,201105012 and 201205008the Basic Scientific Research Fund of the Second Institute of Oceanography of State Oceanic Administration of China under contract Nos JG1108 and JG1219
文摘Surface sediments from the Changjiang River （Yangtze River） Estuary, Hangzhou Bay, and their adjacent waters were analyzed for their grain size distribution, organic carbon （OC） concentration, and stable carbon isotope composition （δ13C）. Based on this analysis, about 36 surface sediment samples were selected from various environments and separated into sand （〉0.250 ram, 0.125-0.250 ram, 0.063-0.125 mm） and silt （0.025-0.063 mm） fractions by wet-sieving fractionation methods, and further into silt- （0.004-0.025 mm） and clay-sized （〈0.004 mm） fractions by centrifugal fractionation. Sediments of six grain size categories were analyzed for their OC and 613C contents to explore the grain size composition and transport paths of sedimentary OC in the study area. From fine to coarse fractions, the OC content was 1.18%, 0.51%, 0.46%, 0.42%, 0.99%, and 0.48%, respectively, while the δ13C was -21.64‰, -22.03‰, -22.52‰, -22.46‰, -22.36‰, and -22.28%0, respectively. In each size category, the OC contribution was 42.96%, 26.06%, 9.82%, 5.75%, 7.09%, and 8.33%, respectively. The OC content in clay and fine silt fractions （〈0.025 ram） was about 69.02%. High OC concentrations were mainly found in offshore modern sediments in the northeast of the Changjiang River Estuary, in modern sediments in the lower estuary of the Changjiang River and Hangzhou Bay, and in Cyclonic Eddy modern sediments to the southwest of the Cheju Island. Integrating the distribution of terrestrial OC content of each grain size category with the δ13C of the bulk sediment indicated that the terrestrial organic material in the Changjiang River Estuary was transported seaward and dispersed to the Cyclonic Eddy modern sediments to the southwest of the Cheju Island via two pathways： one was a result of the Changjiang River Diluted Water （CDW） northeastward extending branch driven by the North Jiangsu Coastal Current and the Yellow Sea Coastal Current, while the other one was the result of the CDW southward extending branch driven by the Taiwan Warm Current.
基金Acknowledgments We are grateful to Dr Michael E Maguire （Case Western Reserve University, USA） for providing the Salmonella mutant strain MM281 and advice on tracer uptake. This work was supported by grants from National Natural Science Foundation of China （30370794）, Hunan Young Scientist Program （03JJY1003）, and Hunan Provincial NSFC （08JJ3088）.
文摘A current-turbidity monitoring system (CTMS) was deployed on the intertidal flat at Wanggang, northern Jiangsu during October 16-17, 2000, to measure the tidal current speeds and seawater turbidities at 5 levels above the seabed. Based upon the logarithmic-profile equation, the boundary layer parameters, i.e., u, z0 and C60, were obtained for 247 tidal flow velocity profiles. Around 90% of the profiles were logarithmic according to the critical correlation coefficient. Internal consistency analysis shows that these parameters derived by different methods are consistent with each other. In addition, the height of the bedforms observed is close to the seabed roughness lengths calculated from the velocity profiles, indicating that the boundary layer parameters obtained can reveal the conditions at the sediment-water interface on the intertidal flats. Suspended sediment concentrations were obtained from the 5 CTMS turbidity meters using laboratory and in-situ calibrations. The results show that the in-situ calibrated SSCs have a much higher accuracy than the laboratory calibrated ones. Calculation of suspended sediment fluxes on the intertidal flats, with a magnitude of 104 kg/m per spring tidal cycle, indicates that suspended sediment moves towards the northwest, which is reversal to the transport pattern controlled by the southward Northern Jiangsu Coastal Current in the sub-tidal zone and adjacent shallow waters.
基金Supported by the National Natural Science Foundation of China(No.41106043)the China Geological Survey(Nos.GZH200800501,GZH200900501)the Open Fund of State Key Laboratory of Marine Geology(No.MG0903)
文摘High-resolution seismic profiles and surface samples were studied in detail in order to determine the structures, provenance, and dynamic mechanisms of a fine-grained deposit in the southeast coastal area of the Liaodong Peninsula, China. Results indicate that there is a prominent fine-grained deposit distributed alongshore up to 14 m thick, which thins out to less than 2 m in both seaward and landward directions, forming an Ω-shaped pattern of cross-section. The deposit is 180-300 km away from the Yalu River mouth and extends along the southeast coast of the Liaodong Peninsula between the northeast of Dalian Bay and southwest of the Changshan Islands, in water depths of 20-40 m. The deposit, which is mainly derived from the Yalu River, represents a Holocene Highstand System Tract sequence formed since the highest sea level around 7.0 ka. The Yalu River-derived sediments were redeposited in the area off the southeast coast of the Liaodong Peninsula after resuspension and transportation by the Liaonan Coastal Current.
文摘Spatial changes in grain size parameters (i.e. grain size trends) contain information on sediment transport patterns. An analytical procedure has been proposed to transform the grain size trends into an image of trend vectors, which may represent net sediment transport pathways. A fundamental assumption for such an approach is that the frequency of occurrence of the trend adopted is much higher in the transport direction, than in any of other directions. Preliminary studies show agreement between this assumption and observations. However, further investigations into the physical processes and mechanisms for the formation of grain size trends are required to improve the technique, including flume experiments and numerical modeling. Moreover, attention should be paid to the trends associated with fine grained sediment, for the method of grain size trend analysis is so far designed for coarse grained material only. The processes of flocculation during settling and the wash load property must be considered. Appropriate interpretation of grain size data will improve our understanding of the physics of granular materials.
文摘Tidal cycle measurements of tidal currents, salinity and water tempe rature, and suspended sediment concentrations were measured at four stations, to gether with surveys along two profiles short core collection within the Yalu Riv er estuary. Grain size analysis of the three core sediment showed that: 1) the s ediment from B1 to B3 became finer, worse sorting and positively skewed; 2) the diversification of matter origin became more and more evident from east to west; 3) the sediments over the region were of the same origin, as indicated by their similar colors and grain sizes. The data indicated that stratification occurred in the flood season, from upstream to downstream, and a salt wedge was formed. The water column was well mixed, but the longitudinal gradient of the salinity w as larger on spring tide. The results also showed that the dominating mechanism of suspended sediment transport in the Yalu River estuary was T1, T2, T3 and T5. The non-tidal steady advection transport was restricted by the net transport o f suspended sediment induced by mass Stoked drift directed to landwards, then th e net sediment transport rate were decreased and the turbidity maxima was also f avored to forming and extending.
文摘The containerized shipment of freight continues to grow rapidly. This development can be traced to a transformation of bulk and break-bulk service to containerization. Demand has been driven by opportunities to broaden logistical options as well as advantageous freight rates. Logisticians and policy makers are unsure how much more bulk traffic can be converted to containerization, but the trends are evident. Of particular interest is grain. Bulk grain handlers have successfully resisted the conversion of grain shipping to containerization, except on the North American-Asian traffic lanes and the Australian-Asian traffic lanes where growth has been significant. This paper reviews the theoretical case for grain containerization from a logistics perspective, followed by an examination of the current trends in the United States and Canada. Subsequently, the analysis considers the restrictions and resistance to the conversion of grain from bulk shipping to containerization.
文摘The German Armed Forces University in Munich has conducted experiments in a laboratory flume to determine the influence of roundness on bed load transport.The investigations were assigned by the German Federal Institute of Hydrology (BIG),with a focus on incipient motion,transport velocity and the depth of mixing into the riverbed. The results of the experiments show that the transport velocity of angular graim is lower and the critical shear stress for incipient motion is slightly higher than of well-ro...
