Nyiragongo volcanic eruptions of 1977 and 2002 emitted silica-undersaturated lavas named melilite-nephelinites with microlithic to sub-porphyritic textures, and consisted of olivine, clinopyroxene (augite), phlogopite...Nyiragongo volcanic eruptions of 1977 and 2002 emitted silica-undersaturated lavas named melilite-nephelinites with microlithic to sub-porphyritic textures, and consisted of olivine, clinopyroxene (augite), phlogopite, melilite, magnetite, and rare plagioclases. This melilite-nephelinite as an evolved rock, shows low SiO<sub>2</sub> (38.40 - 39.52 wt%) and MgO (3.10 - 4.01 wt%), and relatively high FeOt (13.76 - 14.10 wt%), Al<sub>2</sub>O<sub>3</sub> (15.01 - 16.48 wt%), CaO (11.00 - 12.29 wt%) and Na<sub>2</sub>O + K<sub>2</sub>O (10.34 - 11.85 wt%). Unlike LA-ICP-MS on silicate melt inclusions (SMIs) hosted in augite show a pristine melt of picrobasaltic (low Ti-picrite) rock poor in SiO<sub>2</sub> (31.14 - 32.26 wt%), FeOt (2.19 - 2.79 wt%), Al<sub>2</sub>O<sub>3</sub> (8.01 - 9.57 wt%), and Na<sub>2</sub>O + K<sub>2</sub>O (2.34 - 3.05 wt%), while enriched in MgO (20.27 - 28.63 wt%), and CaO (24.95 - 33.17 wt%). The sums (∑REEs) for lavas and SMIs are ranging 712 - 799 and 43 - 119 ppm respectively. REE contracted multi-element patterns showed a W-feature for most lavas except for SMIs. High Rb/Sr, and low Ba/Rb, Zr/Nb, and Sm/Hf ratios of lavas suggest a phlogopite-rich source of materials. .展开更多
Kuwaiti oil production faces a growing challenge in the increasing quantities of produced water generated in the production of oil. The high water cut of the produced fluid from the wells and the high salinity of the ...Kuwaiti oil production faces a growing challenge in the increasing quantities of produced water generated in the production of oil. The high water cut of the produced fluid from the wells and the high salinity of the produced water lead to significant degradation of subsurface equipment, specifically the production tubing. Debris generated through the degradation of the inner part of the tubing becomes a constituent of the scaling that deposits in the tubing and blocks the flow of the production fluid, inducing higher maintenance costs. This paper looks at the characteristics of the scaling in regard to the produced water and outlines the economic impact of the produced water induced degradation of the tubing structure.展开更多
The phosphorite ores-deposits rich in rare earth elements(REE) in Zhijin, Xinhua, Guizhuo occurs in the early Cambrian Meishucun and at the bottom part of Qiongzhusi stage (the upper layer of phosphorites), belonging ...The phosphorite ores-deposits rich in rare earth elements(REE) in Zhijin, Xinhua, Guizhuo occurs in the early Cambrian Meishucun and at the bottom part of Qiongzhusi stage (the upper layer of phosphorites), belonging to Yangzi stratum section. The living creature scraps was proved existent in dolomitic-phosphorites by experiments, The REE could be extracted to provide the worthy data for the further using. Adopting the HNO3 to extract REE, through the ion exchange method, the REE recovery rate could be reached 85.44%, having certain reference value.展开更多
A study of faults and their control of deep gas accumulations has been made on the basis of dividing fault systems in the Xujiaweizi area. The study indicates two sets of fault systems are developed vertically in the ...A study of faults and their control of deep gas accumulations has been made on the basis of dividing fault systems in the Xujiaweizi area. The study indicates two sets of fault systems are developed vertically in the Xujiaweizi area, including a lower fault system and an upper fault system. Formed in the period of the Huoshiling Formation to Yingcheng Formation, the lower fault system consists of five fault systems including Xuxi strike-slip extensional fault system, NE-trending extensional fault system, near-EW-trending regulating fault system, Xuzhong strike-slip fault system and Xudong strike-slip fault system. Formed in the period of Qingshankou Formation to Yaojia Formation, the upper fault system was affected mainly by the boundary conditions of the lower fault system, and thus plenty of muiti-directionally distributed dense fault zones were formed in the T2 reflection horizon. The Xuxi fault controlled the formation and distribution of Shahezi coal-measure source rocks, and Xuzhong and Xndong faults controlled the formation and distribution of volcanic reservoirs of Y1 Member and Y3 Member, respectively. In the forming period of the upper fault system, the Xuzhong fault was of successive strong activities and directly connected gas source rock reservoirs and volcanic reservoirs, so it is a strongly-charged direct gas source fault. The volcanic reservoir development zones of good physical properties that may be found near the Xuzhong fault are the favorable target zones for the next exploration of deep gas accumulations in Xujiaweizi area.展开更多
Awareness of the adverse ecological effects of road and other large construction projects has resulted in a rapidly growing demand to quantitatively predict and evaluate the effects on gene flow among plants and anima...Awareness of the adverse ecological effects of road and other large construction projects has resulted in a rapidly growing demand to quantitatively predict and evaluate the effects on gene flow among plants and animals in natural habitats.In this study,we evaluated the effects of different road construction scenarios on animal species movement by using the methods of ecological landscape connectivity in the typical regions of Yunnan Province,China.The results showed landscape connectivity levels(Probability of Connectivity(PC))decreased after road construction and species with lower dispersal abilities were more affected to the subsequent habitat fragmentation.First level roads affected landscape connectivity most significantly.At a distance of 100 m,the PC index decreased more than 50%.Further analysis suggested that the use of landscape connectivity to assess landscape processes revealed the adverse effects on the species movement more effectively compared with the traditional landscape pattern analysis.In addition,we conducted a graph theory and a least-cost modeling discussion,it is obvious that they are powerful tools to represent and analyze landscape networks with respect to related species movement.Network analysis offers a quantitative and simple but effective tool for ecological process assessment and biological conservation on large scales.展开更多
The research on biofacies and its provincialization is of important significance not only for the increasing of precision of stratigraphic subdivision and correlation in South China, the reconstruction of ancient envi...The research on biofacies and its provincialization is of important significance not only for the increasing of precision of stratigraphic subdivision and correlation in South China, the reconstruction of ancient environment and paleogeography and even the guiding of oil and gas exploration, but also for the study of paleobiogeogrphy and sea level changes of southern China in Ordovician. On the basis of the studies of the ecological characteristics of Ordovician cephalopods from South China, eighteen cephalopod biofacies are recognized and described : (1) Open platform Proterocameroceras biofacies ; (2) Restricted platform Pseudoectenolites-Xiadongoceras biofacies; ( 3 ) Open platform Retroclitendoceras- Pararetroclitendoceras biofacies; (4) Open platform Pronajaceras-Mamagouceras biofacies ; (5) Shelf slope-basin Cyclostomiceras biofacies; (6) Open platform Cameroceras-Cyrtovaginoceras biofacies; (7) Open platform Coreanoceras-Manchuroceras biofacies; (8) Shelf slope-basin Kaipingoceras- Kyminoceras biofacies; (9) Inner shelf Bathmoceras-Protocycloceras biofacies; (10) Middle shelf Dideroceras-Ancistroceras biofacies; (11) Deep-water shelf Lituites-Cyclolituites biofacies ; (12) Stag- nant basin Lituites-Trilacinoceras biofacies; (13) Deep-water basin Paraendoceras-Sactorthoceras biofacies; (14) Deep-water shelf Sinoceras-Michelinoceras-Disoceras biofacies; (15) Deep-water shelf Beloitoceros-Jiangshanoceras biofacies; (16) Deep-water shelf-basin Eurasiaticoceras biofacies; ( 17 ) Shelf-slope Jiangxiceras-Yushanoceras biofacies; (18) Deep-water basin Michelinoceras biofacies. The cephalopods of these biofacies, their ecological characteristics, and living conditions are elucidated in this article. The association law of cephalopod biofacies in time and space shows that there were three cephalopod biofacies provinces in South China during the Ordovician, i.e. , Yangtze biofacies province, East Guizhou (贵州)-West Hunan (湖南) biofacies province (mixed-type biofacies province), and Central Hunan-West Zhejiang (浙江) biofacies province. It is suggested that differentiation of cephalopod biofacies was mainly controlled by sea level changes and tectonic evolution. The differentiation is obvious during lower sea level and not developed during high sea level.展开更多
A geopulse seismic system was implemented to obtain new information on underlying strata beneath the Yellow River Delta. However, owing to the shpping of sea floor and shallow water ( 〈 25 m), free surface-related ...A geopulse seismic system was implemented to obtain new information on underlying strata beneath the Yellow River Delta. However, owing to the shpping of sea floor and shallow water ( 〈 25 m), free surface-related multiples are conflicted with the flat primaries, which may instruct the interpreters in a wrong way and make wrong conclusions. Owing to the variation of multiple periods, standard anti-multiple techniques may lose their power, such as predictive deconvolution. Surface-related multiple elimination methods are introduced to attenuate the multiples based on the underlying waveequation principles. The results justified the method on the single-channel geopulse profile, revealing the real nature of the subsurface.展开更多
Poorly preserved tracks have limited ichnotaxonomic or biotaxon utility,but may reveal useful information about the paleoenvironment,behavior and track taphonomy.Eight mostly parallel to sub parallel trackway segments...Poorly preserved tracks have limited ichnotaxonomic or biotaxon utility,but may reveal useful information about the paleoenvironment,behavior and track taphonomy.Eight mostly parallel to sub parallel trackway segments(T1–T8)were registered on a truncation surface in the Lower Cretaceous Luohe Formation of Shaanxi Province.These attest to the passage of several bipeds,probably all theropods,in a paleo-contour-parallel,south-north direction in an arid setting.Quality of preservation in these trackways is poor,but notably superior in two additional trackways(T9–T10)on a foreset surface.Trackway T9 indicates a didactyl trackmaker,probably a deinonychosaurian,heading north to south.This is the 13th report of deinonychosaurian tracks from the Lower Cretaceous of China.If any or all the eight south-north oriented trackway segments represent continuations of other segments in the same trackways,the total number of individual trackmakers heading in this direction may have been as lowas three.Although the trackway pattern and sedimentological evidence could indicate a physically controlled pathway influencing the direction taken by these trackmakers,the possibility that the trackways also represented small social or gregarious group cannot be ruled out.展开更多
In this study,two possible persistent anomalies of the Madden-Julian Oscillation mode(MJO) are found in the summer season(persistently Pacific active and Indian Ocean active),and an index is set to define the intensit...In this study,two possible persistent anomalies of the Madden-Julian Oscillation mode(MJO) are found in the summer season(persistently Pacific active and Indian Ocean active),and an index is set to define the intensity of the two modes.They are proved to have high statistical correlations to the later ENSO events in the autumn and winter seasons:When persistent anomaly of MJO happens in the Pacific Ocean in summer,El Nino events are often induced during the autumn and winter seasons of that year.However,during the other MJO mode when the summer persistent anomaly of MJO occurs in the Indian Ocean,La Nina events often follow instead.The analysis of the atmospheric circulation field indicates that persistent anomaly of MJO can probably affect the entire Equatorial Pacific circulation,and results in wind stress anomalies.The wind stress anomalies could excite warm or cold water masses which propagate eastwards at the subsurface ocean.The accumulation of warm or cold subsurface water in the Equatorial Eastern Pacific Ocean may eventually lead to the formation of an ENSO.展开更多
The application of pattern recognition technology enables us to solve various human-computer interaction problems that were difficult to solve before.Handwritten Chinese character recognition,as a hot research object ...The application of pattern recognition technology enables us to solve various human-computer interaction problems that were difficult to solve before.Handwritten Chinese character recognition,as a hot research object in image pattern recognition,has many applications in people’s daily life,and more and more scholars are beginning to study off-line handwritten Chinese character recognition.This paper mainly studies the recognition of handwritten Chinese characters by BP(Back Propagation)neural network.Establish a handwritten Chinese character recognition model based on BP neural network,and then verify the accuracy and feasibility of the neural network through GUI(Graphical User Interface)model established by Matlab.This paper mainly includes the following aspects:Firstly,the preprocessing process of handwritten Chinese character recognition in this paper is analyzed.Among them,image preprocessing mainly includes six processes:graying,binarization,smoothing and denoising,character segmentation,histogram equalization and normalization.Secondly,through the comparative selection of feature extraction methods for handwritten Chinese characters,and through the comparative analysis of the results of three different feature extraction methods,the most suitable feature extraction method for this paper is found.Finally,it is the application of BP neural network in handwritten Chinese character recognition.The establishment,training process and parameter selection of BP neural network are described in detail.The simulation software platform chosen in this paper is Matlab,and the sample images are used to train BP neural network to verify the feasibility of Chinese character recognition.Design the GUI interface of human-computer interaction based on Matlab,show the process and results of handwritten Chinese character recognition,and analyze the experimental results.展开更多
The RE and composition of trace elements analysis show that phosphorite-ores are rich in ∑ RE concentration generally in Xinhua, Zhijin.The phosphorites were measured to gather LRE and HRE element.It is higher than o...The RE and composition of trace elements analysis show that phosphorite-ores are rich in ∑ RE concentration generally in Xinhua, Zhijin.The phosphorites were measured to gather LRE and HRE element.It is higher than other rocks.The phosphorite has enriched Y, La and Nd chemical element.There are leading characteristics of concentrated La, LRE and Y, HRE.The chondrite-normalized RE element patterns of the Xinhua dolomitic phosphorite distribute mode for rightwards type to one side of the curve.LRE/HRE > 1, (La/Sm)N > (Gd/Yb)N, and all indicate that LRE content is higher than HRE.The test mode of chemical analysis of single mineral, chemistry phase analysis, scan electric analysis and micro-electronics probe analysis were adopted.The chart of EDAX showed that there was representative element-Y(RE) in exsiting.There was no independent mineral of the RE.It is show that part of the few rare earth chemical element is adsorbed by the clay mineral, much for the type of quality isomorphic form exist in the apatite crystal structure of phosphorite inside.展开更多
Water yield, water supply and quality, wildlife habitat, and ecosystem productivity and services are important societal concerns for natural resource management in the 21st century. Watershed-scale ecohydrologic studi...Water yield, water supply and quality, wildlife habitat, and ecosystem productivity and services are important societal concerns for natural resource management in the 21st century. Watershed-scale ecohydrologic studies can provide needed context for addressing complex spatial and temporal dynamics of these functions and services. This study was conducted on the 5240 ha Turkey Creek watershed (WS 78) draining a 3rd order stream on the Santee Experimental Forest within the South Carolina Atlantic Coastal Plain, USA. The study objectives were to present the hydrologic characteristics of this relatively undisturbed, except by a hurricane (Hugo, 1989), forested water-shed and to discuss key elements for watershed management, including water resource assessment (WRM), modeling integrated water resources management, environmental assessment, land use planning, social impact assessment, and information management. Runoff coefficients, flow duration curves, flood and low flow frequency curves, surface and ground water yields were assessed as elements of the WRM. Results from the last 10 years of interdisciplinary studies have also advanced the understanding of coastal ecohydrologic characteristics and processes, water balance, and their modeling including the need of high resolution LiDAR data. For example, surface water dynamics were shown to be regulated primarily by the water table, dependent upon pre- cipitation and evapotranspiration (ET). Analysis of pre- and post-Hugo streamflow data showed somewhat lower but insignificant (α = 0.05) mean annual flow but increased frequency of larger flows for the post-Hugo compared with the pre-Hugo level. However, there was no significant difference in mean annual ET, potentially indicating the resiliency of this coastal forest. Although the information from this study may be useful for comparison of coastal ecohydrologic issues, it is becoming increasingly clear that multi-site studies may be warranted to understand these complex systems in the face of climate change, sea level rise, and increasing development in coastal regions.展开更多
The Zhaojue(ZJ)tracksites represent multiple steeply-inclined,track-bearing exposures in the clastic Feitianshan Formation of Sichuan Province that have been sequentially,excavated,mapped,expanded and destroyed,by qua...The Zhaojue(ZJ)tracksites represent multiple steeply-inclined,track-bearing exposures in the clastic Feitianshan Formation of Sichuan Province that have been sequentially,excavated,mapped,expanded and destroyed,by quarrying,erosion or collapse,for almost three decades.The quarried area extends for more almost 1.0 km from north to south and-0.5 km from east to west.Four important track-bearing surfaces have been identified and identified as ZJ-Ⅰ,ZJ-Ⅱ,ZJ-ⅡN and ZJ-Ⅲ,some of which are newly exposed surfaces or expanded surfaces that were previously partially described.Others represent surfaces lost since they were first reported in papers published in 2014-2016.The ZJ-Ⅱ site represents a hugely expanded continuation of a much smaller track-bearing surface described in 2014.It was mapped using drone technology,and now represents the largest tracksite in China,with a minimum count of 933 recognizable tracks,and the longest recorded sauropod and ornithopod trackways from China(-80 m and-52 m respectively),which also reveal a pronounced change in the direction of trackmaker movement.The ZJ-Ⅱ surface represents the best Zhaojue paleo-census sample giving a count of 68 individuals from 61 trackways(37 ornithopod,10 theropod,14 sauropod)and isolated tracks(representing 7 individuals).Thus,ornithopods(both large and small trackmakers)represent-54%of the total number of trackways.The smaller ZJ-Ⅲ surface was mapped using traditional methods,and reveals at least 6 ornithopod-and 4 theropod trackways.Both the ZJ-Ⅱ and ZJ-Ⅲ surfaces reveal parallel ornithopod trackways suggestive of social or gregarious behavior.The combined data from all four Zhaojue surfaces reveal a total of 1928 tracks,and include a few previously reported pterosaurs and theropod swim tracks.The Zhaojue quarry complex provide a good example of multiple track-bearing sites(surfaces)that require long term study and monitoring to extract as much trackway data as possible before in situ physical evidence is lost.展开更多
Tracks previously examined between 2002 and 2015 from an incompletely-studied,and now partially lost tracksite site in the Santai Formation of Shandong Province were restudied based on new ex-cavations of additional s...Tracks previously examined between 2002 and 2015 from an incompletely-studied,and now partially lost tracksite site in the Santai Formation of Shandong Province were restudied based on new ex-cavations of additional surfaces.In contrast to the previous reports of tridactyl tracks,including Grallator,the present study discovered an additional assemblage of unequivocal pterosaur tracks(Pteraichnus)and a possible didactyl deinonychosaurian track.The age of the Santai Formation is controversial but it is probably Late Jurassic,which corresponds to the epoch when pterosaur tracks appear worldwide.Age interpretations,based on palynology and isotopic data,tentatively suggests an earlier Middle-Late Jurassic age and might suggest that the pterosaurian tracks are as old or somewhat older than any previously reported.展开更多
Based on the monthly and annual rainfall data of 1955―2000, the multi-time scales characteristics of seasonal and annual rainfall in the past 45 years in the Hebei Plain have been analyzed using Mexican Hat wavelet a...Based on the monthly and annual rainfall data of 1955―2000, the multi-time scales characteristics of seasonal and annual rainfall in the past 45 years in the Hebei Plain have been analyzed using Mexican Hat wavelet analysis in this article. The periodic oscillation of rainfall variation and the points of abrupt change at different time scales along the time series are dis-covered. According to the main periods, the trend of rainfall variation in the future has also been estimated. The results indicate that there are obvious periodic oscillations of 8―12 years and 4―6 years for the seasonal and annual rainfalls variation. The variation trend of the summer rainfall is in agreement with that of the annual rainfall and both of them have the main periods of 1 year and 12 years. It is estimated, based on the main period of 1 year, that the amount of rainfall will be relatively small around 2003 and abundant around 2004―2007 in the Hebei Plain.展开更多
A method of fracture boundary extraction was developed using the Gaussian template and Canny boundary detection on the basis of the collected digital images of natural fractures. The roughness and apertures of the fra...A method of fracture boundary extraction was developed using the Gaussian template and Canny boundary detection on the basis of the collected digital images of natural fractures. The roughness and apertures of the fractures were briefly discussed from the point of view of digital image analysis. The extracted fractured image was translated into a lattice image which can be directly used in numerical simulation. The lattice Boltzmann and modified moment propagation mixed method was then applied to the simulation of solute transport in a natural single fracture, and this mixed method could take the advantages of the lattice Boltzmann method in dealing with complex physical boundaries. The obtained concentrations was fitted with the CXTFIT2.1 code and compared with the results obtained with the commercial software Feflow. The comparison indicates that the simulation using the mixed method is sound.展开更多
文摘Nyiragongo volcanic eruptions of 1977 and 2002 emitted silica-undersaturated lavas named melilite-nephelinites with microlithic to sub-porphyritic textures, and consisted of olivine, clinopyroxene (augite), phlogopite, melilite, magnetite, and rare plagioclases. This melilite-nephelinite as an evolved rock, shows low SiO<sub>2</sub> (38.40 - 39.52 wt%) and MgO (3.10 - 4.01 wt%), and relatively high FeOt (13.76 - 14.10 wt%), Al<sub>2</sub>O<sub>3</sub> (15.01 - 16.48 wt%), CaO (11.00 - 12.29 wt%) and Na<sub>2</sub>O + K<sub>2</sub>O (10.34 - 11.85 wt%). Unlike LA-ICP-MS on silicate melt inclusions (SMIs) hosted in augite show a pristine melt of picrobasaltic (low Ti-picrite) rock poor in SiO<sub>2</sub> (31.14 - 32.26 wt%), FeOt (2.19 - 2.79 wt%), Al<sub>2</sub>O<sub>3</sub> (8.01 - 9.57 wt%), and Na<sub>2</sub>O + K<sub>2</sub>O (2.34 - 3.05 wt%), while enriched in MgO (20.27 - 28.63 wt%), and CaO (24.95 - 33.17 wt%). The sums (∑REEs) for lavas and SMIs are ranging 712 - 799 and 43 - 119 ppm respectively. REE contracted multi-element patterns showed a W-feature for most lavas except for SMIs. High Rb/Sr, and low Ba/Rb, Zr/Nb, and Sm/Hf ratios of lavas suggest a phlogopite-rich source of materials. .
文摘Kuwaiti oil production faces a growing challenge in the increasing quantities of produced water generated in the production of oil. The high water cut of the produced fluid from the wells and the high salinity of the produced water lead to significant degradation of subsurface equipment, specifically the production tubing. Debris generated through the degradation of the inner part of the tubing becomes a constituent of the scaling that deposits in the tubing and blocks the flow of the production fluid, inducing higher maintenance costs. This paper looks at the characteristics of the scaling in regard to the produced water and outlines the economic impact of the produced water induced degradation of the tubing structure.
基金Project supported by the National Natural Science Foundation of China (40372047, 50164001)
文摘The phosphorite ores-deposits rich in rare earth elements(REE) in Zhijin, Xinhua, Guizhuo occurs in the early Cambrian Meishucun and at the bottom part of Qiongzhusi stage (the upper layer of phosphorites), belonging to Yangzi stratum section. The living creature scraps was proved existent in dolomitic-phosphorites by experiments, The REE could be extracted to provide the worthy data for the further using. Adopting the HNO3 to extract REE, through the ion exchange method, the REE recovery rate could be reached 85.44%, having certain reference value.
基金supported by the National Natural Foundation Project Polygonal Fault Genetic Mechanism and its Reservoir Controlling Mechanism in Rift Basin (number: 41072163) financial aid
文摘A study of faults and their control of deep gas accumulations has been made on the basis of dividing fault systems in the Xujiaweizi area. The study indicates two sets of fault systems are developed vertically in the Xujiaweizi area, including a lower fault system and an upper fault system. Formed in the period of the Huoshiling Formation to Yingcheng Formation, the lower fault system consists of five fault systems including Xuxi strike-slip extensional fault system, NE-trending extensional fault system, near-EW-trending regulating fault system, Xuzhong strike-slip fault system and Xudong strike-slip fault system. Formed in the period of Qingshankou Formation to Yaojia Formation, the upper fault system was affected mainly by the boundary conditions of the lower fault system, and thus plenty of muiti-directionally distributed dense fault zones were formed in the T2 reflection horizon. The Xuxi fault controlled the formation and distribution of Shahezi coal-measure source rocks, and Xuzhong and Xndong faults controlled the formation and distribution of volcanic reservoirs of Y1 Member and Y3 Member, respectively. In the forming period of the upper fault system, the Xuzhong fault was of successive strong activities and directly connected gas source rock reservoirs and volcanic reservoirs, so it is a strongly-charged direct gas source fault. The volcanic reservoir development zones of good physical properties that may be found near the Xuzhong fault are the favorable target zones for the next exploration of deep gas accumulations in Xujiaweizi area.
基金Under the auspices of Nonprofit Environment Protection Specific Project of China(No.201209029-4)
文摘Awareness of the adverse ecological effects of road and other large construction projects has resulted in a rapidly growing demand to quantitatively predict and evaluate the effects on gene flow among plants and animals in natural habitats.In this study,we evaluated the effects of different road construction scenarios on animal species movement by using the methods of ecological landscape connectivity in the typical regions of Yunnan Province,China.The results showed landscape connectivity levels(Probability of Connectivity(PC))decreased after road construction and species with lower dispersal abilities were more affected to the subsequent habitat fragmentation.First level roads affected landscape connectivity most significantly.At a distance of 100 m,the PC index decreased more than 50%.Further analysis suggested that the use of landscape connectivity to assess landscape processes revealed the adverse effects on the species movement more effectively compared with the traditional landscape pattern analysis.In addition,we conducted a graph theory and a least-cost modeling discussion,it is obvious that they are powerful tools to represent and analyze landscape networks with respect to related species movement.Network analysis offers a quantitative and simple but effective tool for ecological process assessment and biological conservation on large scales.
基金This paper is supported by the National Natural Science Foundation of China (No .40272060) .
文摘The research on biofacies and its provincialization is of important significance not only for the increasing of precision of stratigraphic subdivision and correlation in South China, the reconstruction of ancient environment and paleogeography and even the guiding of oil and gas exploration, but also for the study of paleobiogeogrphy and sea level changes of southern China in Ordovician. On the basis of the studies of the ecological characteristics of Ordovician cephalopods from South China, eighteen cephalopod biofacies are recognized and described : (1) Open platform Proterocameroceras biofacies ; (2) Restricted platform Pseudoectenolites-Xiadongoceras biofacies; ( 3 ) Open platform Retroclitendoceras- Pararetroclitendoceras biofacies; (4) Open platform Pronajaceras-Mamagouceras biofacies ; (5) Shelf slope-basin Cyclostomiceras biofacies; (6) Open platform Cameroceras-Cyrtovaginoceras biofacies; (7) Open platform Coreanoceras-Manchuroceras biofacies; (8) Shelf slope-basin Kaipingoceras- Kyminoceras biofacies; (9) Inner shelf Bathmoceras-Protocycloceras biofacies; (10) Middle shelf Dideroceras-Ancistroceras biofacies; (11) Deep-water shelf Lituites-Cyclolituites biofacies ; (12) Stag- nant basin Lituites-Trilacinoceras biofacies; (13) Deep-water basin Paraendoceras-Sactorthoceras biofacies; (14) Deep-water shelf Sinoceras-Michelinoceras-Disoceras biofacies; (15) Deep-water shelf Beloitoceros-Jiangshanoceras biofacies; (16) Deep-water shelf-basin Eurasiaticoceras biofacies; ( 17 ) Shelf-slope Jiangxiceras-Yushanoceras biofacies; (18) Deep-water basin Michelinoceras biofacies. The cephalopods of these biofacies, their ecological characteristics, and living conditions are elucidated in this article. The association law of cephalopod biofacies in time and space shows that there were three cephalopod biofacies provinces in South China during the Ordovician, i.e. , Yangtze biofacies province, East Guizhou (贵州)-West Hunan (湖南) biofacies province (mixed-type biofacies province), and Central Hunan-West Zhejiang (浙江) biofacies province. It is suggested that differentiation of cephalopod biofacies was mainly controlled by sea level changes and tectonic evolution. The differentiation is obvious during lower sea level and not developed during high sea level.
基金The workis financially supported by the High Technology Research and Development Program of China(863 Program,Grant No.2006AA09Z339)Natural Science Foundation of Shandong Province(Grant No.Y2006E09)
文摘A geopulse seismic system was implemented to obtain new information on underlying strata beneath the Yellow River Delta. However, owing to the shpping of sea floor and shallow water ( 〈 25 m), free surface-related multiples are conflicted with the flat primaries, which may instruct the interpreters in a wrong way and make wrong conclusions. Owing to the variation of multiple periods, standard anti-multiple techniques may lose their power, such as predictive deconvolution. Surface-related multiple elimination methods are introduced to attenuate the multiples based on the underlying waveequation principles. The results justified the method on the single-channel geopulse profile, revealing the real nature of the subsurface.
基金the National Natural Science Foundation of China(No.41888101,41790455,41772008)the 111 project(B20011)。
文摘Poorly preserved tracks have limited ichnotaxonomic or biotaxon utility,but may reveal useful information about the paleoenvironment,behavior and track taphonomy.Eight mostly parallel to sub parallel trackway segments(T1–T8)were registered on a truncation surface in the Lower Cretaceous Luohe Formation of Shaanxi Province.These attest to the passage of several bipeds,probably all theropods,in a paleo-contour-parallel,south-north direction in an arid setting.Quality of preservation in these trackways is poor,but notably superior in two additional trackways(T9–T10)on a foreset surface.Trackway T9 indicates a didactyl trackmaker,probably a deinonychosaurian,heading north to south.This is the 13th report of deinonychosaurian tracks from the Lower Cretaceous of China.If any or all the eight south-north oriented trackway segments represent continuations of other segments in the same trackways,the total number of individual trackmakers heading in this direction may have been as lowas three.Although the trackway pattern and sedimentological evidence could indicate a physically controlled pathway influencing the direction taken by these trackmakers,the possibility that the trackways also represented small social or gregarious group cannot be ruled out.
基金National Natural Science Foundation of China(41375059)National Public Welfare(Meteorological Sector)Special Project of China(GYHY201306022)
文摘In this study,two possible persistent anomalies of the Madden-Julian Oscillation mode(MJO) are found in the summer season(persistently Pacific active and Indian Ocean active),and an index is set to define the intensity of the two modes.They are proved to have high statistical correlations to the later ENSO events in the autumn and winter seasons:When persistent anomaly of MJO happens in the Pacific Ocean in summer,El Nino events are often induced during the autumn and winter seasons of that year.However,during the other MJO mode when the summer persistent anomaly of MJO occurs in the Indian Ocean,La Nina events often follow instead.The analysis of the atmospheric circulation field indicates that persistent anomaly of MJO can probably affect the entire Equatorial Pacific circulation,and results in wind stress anomalies.The wind stress anomalies could excite warm or cold water masses which propagate eastwards at the subsurface ocean.The accumulation of warm or cold subsurface water in the Equatorial Eastern Pacific Ocean may eventually lead to the formation of an ENSO.
文摘The application of pattern recognition technology enables us to solve various human-computer interaction problems that were difficult to solve before.Handwritten Chinese character recognition,as a hot research object in image pattern recognition,has many applications in people’s daily life,and more and more scholars are beginning to study off-line handwritten Chinese character recognition.This paper mainly studies the recognition of handwritten Chinese characters by BP(Back Propagation)neural network.Establish a handwritten Chinese character recognition model based on BP neural network,and then verify the accuracy and feasibility of the neural network through GUI(Graphical User Interface)model established by Matlab.This paper mainly includes the following aspects:Firstly,the preprocessing process of handwritten Chinese character recognition in this paper is analyzed.Among them,image preprocessing mainly includes six processes:graying,binarization,smoothing and denoising,character segmentation,histogram equalization and normalization.Secondly,through the comparative selection of feature extraction methods for handwritten Chinese characters,and through the comparative analysis of the results of three different feature extraction methods,the most suitable feature extraction method for this paper is found.Finally,it is the application of BP neural network in handwritten Chinese character recognition.The establishment,training process and parameter selection of BP neural network are described in detail.The simulation software platform chosen in this paper is Matlab,and the sample images are used to train BP neural network to verify the feasibility of Chinese character recognition.Design the GUI interface of human-computer interaction based on Matlab,show the process and results of handwritten Chinese character recognition,and analyze the experimental results.
基金Projbect supported by the National Natural Science Foundation of China(50164001 )
文摘The RE and composition of trace elements analysis show that phosphorite-ores are rich in ∑ RE concentration generally in Xinhua, Zhijin.The phosphorites were measured to gather LRE and HRE element.It is higher than other rocks.The phosphorite has enriched Y, La and Nd chemical element.There are leading characteristics of concentrated La, LRE and Y, HRE.The chondrite-normalized RE element patterns of the Xinhua dolomitic phosphorite distribute mode for rightwards type to one side of the curve.LRE/HRE > 1, (La/Sm)N > (Gd/Yb)N, and all indicate that LRE content is higher than HRE.The test mode of chemical analysis of single mineral, chemistry phase analysis, scan electric analysis and micro-electronics probe analysis were adopted.The chart of EDAX showed that there was representative element-Y(RE) in exsiting.There was no independent mineral of the RE.It is show that part of the few rare earth chemical element is adsorbed by the clay mineral, much for the type of quality isomorphic form exist in the apatite crystal structure of phosphorite inside.
文摘Water yield, water supply and quality, wildlife habitat, and ecosystem productivity and services are important societal concerns for natural resource management in the 21st century. Watershed-scale ecohydrologic studies can provide needed context for addressing complex spatial and temporal dynamics of these functions and services. This study was conducted on the 5240 ha Turkey Creek watershed (WS 78) draining a 3rd order stream on the Santee Experimental Forest within the South Carolina Atlantic Coastal Plain, USA. The study objectives were to present the hydrologic characteristics of this relatively undisturbed, except by a hurricane (Hugo, 1989), forested water-shed and to discuss key elements for watershed management, including water resource assessment (WRM), modeling integrated water resources management, environmental assessment, land use planning, social impact assessment, and information management. Runoff coefficients, flow duration curves, flood and low flow frequency curves, surface and ground water yields were assessed as elements of the WRM. Results from the last 10 years of interdisciplinary studies have also advanced the understanding of coastal ecohydrologic characteristics and processes, water balance, and their modeling including the need of high resolution LiDAR data. For example, surface water dynamics were shown to be regulated primarily by the water table, dependent upon pre- cipitation and evapotranspiration (ET). Analysis of pre- and post-Hugo streamflow data showed somewhat lower but insignificant (α = 0.05) mean annual flow but increased frequency of larger flows for the post-Hugo compared with the pre-Hugo level. However, there was no significant difference in mean annual ET, potentially indicating the resiliency of this coastal forest. Although the information from this study may be useful for comparison of coastal ecohydrologic issues, it is becoming increasingly clear that multi-site studies may be warranted to understand these complex systems in the face of climate change, sea level rise, and increasing development in coastal regions.
基金funded by the National Natural Science Foundation of China(Grant No.41772008,41772023)the 111 project(Grant No.B20011).
文摘The Zhaojue(ZJ)tracksites represent multiple steeply-inclined,track-bearing exposures in the clastic Feitianshan Formation of Sichuan Province that have been sequentially,excavated,mapped,expanded and destroyed,by quarrying,erosion or collapse,for almost three decades.The quarried area extends for more almost 1.0 km from north to south and-0.5 km from east to west.Four important track-bearing surfaces have been identified and identified as ZJ-Ⅰ,ZJ-Ⅱ,ZJ-ⅡN and ZJ-Ⅲ,some of which are newly exposed surfaces or expanded surfaces that were previously partially described.Others represent surfaces lost since they were first reported in papers published in 2014-2016.The ZJ-Ⅱ site represents a hugely expanded continuation of a much smaller track-bearing surface described in 2014.It was mapped using drone technology,and now represents the largest tracksite in China,with a minimum count of 933 recognizable tracks,and the longest recorded sauropod and ornithopod trackways from China(-80 m and-52 m respectively),which also reveal a pronounced change in the direction of trackmaker movement.The ZJ-Ⅱ surface represents the best Zhaojue paleo-census sample giving a count of 68 individuals from 61 trackways(37 ornithopod,10 theropod,14 sauropod)and isolated tracks(representing 7 individuals).Thus,ornithopods(both large and small trackmakers)represent-54%of the total number of trackways.The smaller ZJ-Ⅲ surface was mapped using traditional methods,and reveals at least 6 ornithopod-and 4 theropod trackways.Both the ZJ-Ⅱ and ZJ-Ⅲ surfaces reveal parallel ornithopod trackways suggestive of social or gregarious behavior.The combined data from all four Zhaojue surfaces reveal a total of 1928 tracks,and include a few previously reported pterosaurs and theropod swim tracks.The Zhaojue quarry complex provide a good example of multiple track-bearing sites(surfaces)that require long term study and monitoring to extract as much trackway data as possible before in situ physical evidence is lost.
基金the National Natural Science Foundation of China(No.41888101)the 111 project(B20011)the Fundamental Research Funds for Central Universities(265QZ201903).
文摘Tracks previously examined between 2002 and 2015 from an incompletely-studied,and now partially lost tracksite site in the Santai Formation of Shandong Province were restudied based on new ex-cavations of additional surfaces.In contrast to the previous reports of tridactyl tracks,including Grallator,the present study discovered an additional assemblage of unequivocal pterosaur tracks(Pteraichnus)and a possible didactyl deinonychosaurian track.The age of the Santai Formation is controversial but it is probably Late Jurassic,which corresponds to the epoch when pterosaur tracks appear worldwide.Age interpretations,based on palynology and isotopic data,tentatively suggests an earlier Middle-Late Jurassic age and might suggest that the pterosaurian tracks are as old or somewhat older than any previously reported.
基金This work was supported by the National Natural Science Foundation of China(Grant No.40335046).
文摘Based on the monthly and annual rainfall data of 1955―2000, the multi-time scales characteristics of seasonal and annual rainfall in the past 45 years in the Hebei Plain have been analyzed using Mexican Hat wavelet analysis in this article. The periodic oscillation of rainfall variation and the points of abrupt change at different time scales along the time series are dis-covered. According to the main periods, the trend of rainfall variation in the future has also been estimated. The results indicate that there are obvious periodic oscillations of 8―12 years and 4―6 years for the seasonal and annual rainfalls variation. The variation trend of the summer rainfall is in agreement with that of the annual rainfall and both of them have the main periods of 1 year and 12 years. It is estimated, based on the main period of 1 year, that the amount of rainfall will be relatively small around 2003 and abundant around 2004―2007 in the Hebei Plain.
基金Project supported by the National Natural Science Foundation of China(Grant No.50579012).
文摘A method of fracture boundary extraction was developed using the Gaussian template and Canny boundary detection on the basis of the collected digital images of natural fractures. The roughness and apertures of the fractures were briefly discussed from the point of view of digital image analysis. The extracted fractured image was translated into a lattice image which can be directly used in numerical simulation. The lattice Boltzmann and modified moment propagation mixed method was then applied to the simulation of solute transport in a natural single fracture, and this mixed method could take the advantages of the lattice Boltzmann method in dealing with complex physical boundaries. The obtained concentrations was fitted with the CXTFIT2.1 code and compared with the results obtained with the commercial software Feflow. The comparison indicates that the simulation using the mixed method is sound.