To analyze the composition and structure of the pale blue outcrop from the UBC Cliffs and research the environmental significance of aerinite recorded in the sediments, mineral composition, bulk chemical composition a...To analyze the composition and structure of the pale blue outcrop from the UBC Cliffs and research the environmental significance of aerinite recorded in the sediments, mineral composition, bulk chemical composition and structural analyses were carried out by means of X-ray diffraction(XRD), field emission scanning electron microscope(FESEM), transmission electron microscope(TEM), electron microprobe analysis(EMPA) and X-ray fluorescence spectra(XRF). Quartz, feldspar, mica, chlorite and aerinite as well as a small amount of amphibole, calcite, clinopyroxene, rutile, perovskite and apatite are recorded in the sediments. It is reported for the first time that the aerinite occurs in a high latitude area and in sediments paragenetic with mica and chlorite. The large span in grain size shows a typical characteristic of fluvioglacial sediments. Geochemistry characteristics(CIA, CIW, PIA, WIP and ICV) verify that there is virtually no chemical weathering. Mineralogy and geochemistry features of the UBC Cliffs sediments indicate that aerinite is accommodate to the high latitude and cold, dry climate. As the sediments show high similarity to those of their provenance, they have great significance in the identification of the forming condition and origin of the aerinite.展开更多
A composite fall-slippage model is proposed in this study for the Tertiary sedimentary coastal cliffs of Varkala in the western coastal tract of Peninsular India which are retreating landwards due to the combination o...A composite fall-slippage model is proposed in this study for the Tertiary sedimentary coastal cliffs of Varkala in the western coastal tract of Peninsular India which are retreating landwards due to the combination of several factors.The fall model in the present study accounts both spring seepage and wave action,resulting in undercutting and this fall affects only the topmost laterite and the just below sandstone in the cliff.Slippage in this area affects all the litho-units and hence the geologic characteristics of all the litho-units are considered for developing the slippage model.This mathematically derived model can be used in other cliffs exhibiting the same morphology as well as the one controlled by the same influencing factors.This model differs from other models in incorporating multi-lithounits as well as multi-notches.Varkala cliffs form a part of the aspiring geopark in the Global Geopark Network and hence a study on the cliff recession is a pressing requirement.展开更多
This work presents the behavior of Segou sandstones in the laboratory and in the field conditions. Four types of sandstone are collected in the northern part of the Madina Kouta basin (eastern Senegal). These types of...This work presents the behavior of Segou sandstones in the laboratory and in the field conditions. Four types of sandstone are collected in the northern part of the Madina Kouta basin (eastern Senegal). These types of specimens are the white sandstones, the red sandstones, the purple sandstones and the sandstones with intercalation of pelites. Uniaxial tests are carried out on these specimens of sandstones. The Young Moduli (E) and the Uniaxial Compression Strengths (Rc) are higher for the white sandstone. Values of the mechanical parameters decrease slightly for red sandstones due to an increase of the amount of pelites in the composition of the rock. Decrease of mechanical parameters is more important for the purple facies due to an important network of fractures. The facies with weaker characteristics corresponds to the sandstones with intercalation of pelites. This is due to the soft nature of the pelites. The slope stability of the Cliff sides depends also on to these characteristics.展开更多
Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast...Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast coast of Algeria by identifying the key factors contributing to rockfall occurrence.We employed a combination of kinematic analysis,Matterocking method,and 3D trajectory simulations to determine zones that are susceptible to rockfall mobilization.By using a probabilistic and structural approach in conjunction with photogrammetry,we identified the controlling factors.The kinematic analysis revealed the presence of five discontinuity families,which indicated both plane and wedge failure modes.The 3D trajectory simulations demonstrated that the falling blocks followed the stream direction.We then validated the susceptibility maps generated from the analysis using aerial photos and historical rockfall events.The findings of this study enhance our understanding of rockfall phenomena and provide valuable insights for the development of effective strategies to mitigate rockfall hazards.展开更多
White puffy clouds drift past a bungalow facing a deep valley and a towering peak beyond it.Chirps of birds animate the idyllic scene without shattering its serenity.The bungalow with a wood-plank roof and mud walls i...White puffy clouds drift past a bungalow facing a deep valley and a towering peak beyond it.Chirps of birds animate the idyllic scene without shattering its serenity.The bungalow with a wood-plank roof and mud walls is featured in a video clip that Mouse Labo posted online on April 13.展开更多
Just as the cliff serves as a demarcation between two different worlds, there seems to the protagonist in The Catcher in the Rye the dichotomies between innocence and corruption, children and adults. While these duali...Just as the cliff serves as a demarcation between two different worlds, there seems to the protagonist in The Catcher in the Rye the dichotomies between innocence and corruption, children and adults. While these dualisms are projected in the story, they are also deconstructed and the characterization of Holden clearly shows the instability of those dualisms.展开更多
在美国,社会经济快速发展,新潮词语层出不穷,其中包括一部分为数不少的简写词。现介绍一些如下: 1.BF best friend(最好的朋友)的简写。青年人喜欢交友,言谈中也是三句话不离“我最好的朋友”。为简便起见,干脆简称BF。如: Are you ther...在美国,社会经济快速发展,新潮词语层出不穷,其中包括一部分为数不少的简写词。现介绍一些如下: 1.BF best friend(最好的朋友)的简写。青年人喜欢交友,言谈中也是三句话不离“我最好的朋友”。为简便起见,干脆简称BF。如: Are you there for your BF when he gets intotrouble?当你最好的朋友生活不顺时,你在他身边吗?展开更多
The North Branch, separated by the Chongming Island, was once the main channel in the estuary of the Changjiang River. Reclamation and a decrease in runoffto the North Branch had led to the narrowing and shallowing of...The North Branch, separated by the Chongming Island, was once the main channel in the estuary of the Changjiang River. Reclamation and a decrease in runoffto the North Branch had led to the narrowing and shallowing of the channel. The Yuantuojiao Point is located at the intersecting point connecting the North Branch of the Changjiang River and the Jiangsu coastline. Erosion cliffs are developed between the typical silty-muddy tidal flat and the salt marsh occupied by Spartina alterniflorea, and this has changed rapidly over the past few years. The sediment grain size analysis results of the surficial and two core samples indi- cate that the Yuantuoiiao Point tidal fiat experienced continuous accretional processes. Based upon 137Cs analysis results of the YT and YY Cores sampled from the tidal flat at the Yuantuojiao Point, the average sed- imentation rate of the YT Core was 2.30 cm/a from 1963 to 2007, and 2.38 cm/a from 1954 to 2007 for the YY Core. The sedimentation rates of both core locations have declined since the 1960s corresponding to the seaward reclamation at the Yuantuojiao Point. The average sedimentation rates at the Yuantnojiao Point were similar to that of the silty-muddy tidal flat at the northern ]iangsu coast, but lower than that of the south of the Changjiang River Estuary. According to field morphological investigations from 2006 to 2008 on the salt marsh at the Yuantuojiao Point, cliffs retreated markedly by storm surges and disappeared gradu- ally because of the rapid sedimentation on the silty-muddy tidal flat. The maximum annual retreat reached 10 m. The recent sedimentation and morphological changes of the Yuantuojiao Point tidal flat not only displayed the retreat of the salt marsh and the disappearance of cliffs, but also was accompanied by rapid sedimentation of the silty-muddy tidal flat and the salt marsh, indicating the responses to the tidal currents, storm surges, Spartina alterniflorea trapping sediments and large-scale reclamation. The sediment grain size and their trends, southward coastal flow, and sandspits of the longshore bars suggest that the main sediment source at the Yuantuoijao Point, estuary of the North Branch was possibly from the Changjiang River before 1958, since then, it has been from the south of the submarine radial sand ridges of the southern Huanghai Sea （Yellow Sea）.展开更多
Based on the field surveys and repeated cross-profile observations combined with the comparison of many years’ topog-raphic maps,this study shows the spatial variability and varying patterns of coastal erosion along ...Based on the field surveys and repeated cross-profile observations combined with the comparison of many years’ topog-raphic maps,this study shows the spatial variability and varying patterns of coastal erosion along the west coast of the Taiwan Strait.Regional differentiation in the Meso-Cenozoic coastal tectonics determined the irregular coastline and geological background for large-scale coastal erosion distribution.The intensity of coastal erosion on the west side of the Taiwan Strait is mild in the northern region,severe in the central region and modest in the southern region.The beaches along the coast are mainly backed by dunes,sea-walls or cliffs.The dunes and beaches show periodic erosion and recovery along the coast adjacent to river mouths,while persistent retreat of frontal dunes and beaches tends to occur in other areas.The beach erosion occurs mainly in front of seawalls.Due to the low strength of the unconsolidated sediment the soft cliffs suffer the severest coastline recession.Sea level rise and river sediment discharge reduction are main causes of coastal erosion.Storm surge is common in the studied area and plays an important role in the progress of coastal erosion.Human activities including coastal constructions and sand mining also tend to interfere strongly with the balance of sediment budget in some coastal cells.展开更多
A model for calculating the erosion distance of soft sea cliff under wave loading is established based on the erosion mechanism of soft sea cliff under wave loading and for considering wave hydrodynamic and sea cliff ...A model for calculating the erosion distance of soft sea cliff under wave loading is established based on the erosion mechanism of soft sea cliff under wave loading and for considering wave hydrodynamic and sea cliff material parameters.The model is verified,and the parameters are regressed using an indoor flume experiment.The erosion distances of the sea cliff in the northeast of the Pingtan Island are calculated by the model,and the results are compared with the measured data.The maximum erosion occurs in static water level,the location of the maximum erosion moves up as the wave continues,and the erosion stops when the wave lasts for a period of time.The erosion does not occur until the wave height exceeds a critical value; however,the contribution of large waves to the erosion is not relatively substantial.The calculated erosion distances at two places in the northeast of Pingtan Island are 0.32 m and 0.26 m.展开更多
美国专家路易·克鲁在批改一位中国学生的英语作文时,将其中描写山景的一个句于In front.it was the sharp slope of a cliff改成:Thefront cliff sloped sharply.同一个 slope,由名词改为动词,前后两个句子的结构和气势便立时大不...美国专家路易·克鲁在批改一位中国学生的英语作文时,将其中描写山景的一个句于In front.it was the sharp slope of a cliff改成:Thefront cliff sloped sharply.同一个 slope,由名词改为动词,前后两个句子的结构和气势便立时大不一样.在现代英语中,越来越多的名词被当作动词使用,它们往往都能收到句式简炼,形象逼真的修辞效果。试看下面两个例句: Investigation fathered the baby on him.展开更多
Rocky habitats are regarded as biodiversity hot-spots. Along with high species diversity, diverse ecological relationships can be observed in these habitats. Large groups of bird species use rocks in various ways： as...Rocky habitats are regarded as biodiversity hot-spots. Along with high species diversity, diverse ecological relationships can be observed in these habitats. Large groups of bird species use rocks in various ways： as perching/roosting sites, breeding or foraging habitats, information exchange sites, display arenas or as sources of minerals and water. Because of the inaccessibility of these environments, their role and importance to animals has been underestimated. We evaluated the use of rocky habitats by birds in the Tatra Mountains （49°13′N; 19°57′E, Carpathians, central Europe）. Rocky habitats were used by 29 bird species, eight of which used cliffs directly （i.e. for nesting, foraging or resting）. The number of species recorded as using cliffs was correlated with the surface area of the cliff face. A total of 2o forms of rocky habitat use were recorded, in five behavioural categories： vocalization, foraging, perching, flight and nesting. Prevailing behaviours were flying by a rock face, circling above the face, and vocalization on a tree/shrub growing next to a rock. Rocks provide a nesting habitat for specialized petrophilic species and permit the existence of numerous ecological relations between species and habitats. The results of this study show that rocky habitats support the diversity of ecological relationships.展开更多
Cliff deformation behavior after conservation is of great significance for evaluating the conservation effect and discovering the dynamical law of soil. Modeling on deformation behavior is beneficial to the quantitati...Cliff deformation behavior after conservation is of great significance for evaluating the conservation effect and discovering the dynamical law of soil. Modeling on deformation behavior is beneficial to the quantitative evaluation of interactions between soil mass and structures as well as the forecast. Based on cliff conservation engineering of Jiaohe Ruins （the largest raw soil heritage site in the world）, data of horizontal deformation of the upper cliff were obtained by using Nanrui-made NDW-50 displacement device （precision： 0.01 mm, frequency： 15 min^-l）. Regression analysis indicates that deformation behavior models include exponential growth, linear growth and parabolic growth types, while daily deformation presents more intense periodicity （24 h）. The deformation is less than 1.5 mm during monitoring period, which has no impact on the stability of cliff. Deformation behavior provides the mutual duress and interaction between soil and engineering intervention. In addition, deformation mode attaches tensely to the damage pattern of the cliff. The conclusions are of importance to the stability evaluation of the carrier along Silk Road.展开更多
Based on site studies, historical literature investigation and academic communication, this work aims to dig out the cultural significance in architectural and religious aspects conveyed in cliff carvings in the Bashu...Based on site studies, historical literature investigation and academic communication, this work aims to dig out the cultural significance in architectural and religious aspects conveyed in cliff carvings in the Bashu region. After casting a glance at the origin and evolution of Bashu culture and religion mainly involving Daoism and Buddhism recorded in forms of cliff carvings, we concentrated on discovering the national, regional and folk architectural characters implicated in cliff carvings at different sites within the Bashu region. The cliff carvings in this region vividly depicted the evolution of the architectural culture hereof. The essence of their religious and architectural connotations can be good stuff to be input in today’s architectural design philosophy.展开更多
The aim of this work is to map the susceptibility of sites to landslides. To assess the susceptibility of the zone, GIS techniques were used. Susceptibility factors are selected and split into two groups: active and p...The aim of this work is to map the susceptibility of sites to landslides. To assess the susceptibility of the zone, GIS techniques were used. Susceptibility factors are selected and split into two groups: active and passive factors. Passive factors regroup all the intrinsic conditions existing on the field at all times. The active factors or triggering factors are present sporadically and are added to the passive factors to trigger a landslide. With the weighted overlay method using ArcGIS?, four scenarios have been developed. A first scenario where only passive factors are combined and three scenarios for which we have for each scenario the passive factors combined with an active factor. With these different scenarios, five levels of susceptibility are obtained in the zone. These levels range from very low to very high susceptibility. For the different scenarios, the results show that the zone consists mainly of very low to low susceptibility with at least 61% of the area, followed by moderate susceptibility (23.54% to 38.24%) and last land with high susceptibility to very high with less than 1% of the surface. Fields with high to very high susceptibility are located on the slopes of the hills. Among the active factors, only the rainfall significantly modifies the percentage of land susceptible to landslide but remains in the field of moderate susceptibility. The predicted susceptibilities are closer to the observed landslides around the Thies Cliff than to the Dias Horst.展开更多
A decrease in the amount of precipitation is observed on average 18 - 20 mm compared with the periods before the Aral crisis and the average annual temperature rise over the long-term period is 2.0°C in the Centr...A decrease in the amount of precipitation is observed on average 18 - 20 mm compared with the periods before the Aral crisis and the average annual temperature rise over the long-term period is 2.0°C in the Central part of Ustyurt. An increase in the Si index meaning an increase in the degree of drought every ten-flight is clearly expressed in the months March-July. Data Analysis 1981-2017 shows that within 36 years the species diversity in the monitoring sites of Kabanbay decreased by 2 - 3 times. In 1981 the number of species fluctuated between the values of 9 - 50, and in 2017 this figure is 4 - 17. The results of the analysis show that the forecast indicators of the old-current state (1981) of the vegetation coverage and number of species were stable or had tendencies with a low regressive character (r2 = 0.01). However, the current-state (2017) of the vegetation coverage and the species composition of the monitoring plots showed a low progressive trend (r2 = 0.03), i.e. in the future, the formation of plant communities with low vegetation coverage and species composition has a dominant status. The results show that in 1981, 65% - 80% of the species composition of plant communities consisted of halophyte and xerophyte groups. In 2017, this figure reaches 80% - 100%, i.e. this claims to increase xerophytization and halophytization of territories. An interesting fact is established with mesophyte group. In general, theoretically, the decrease in the number of mesophyte group of plants for 1981-2017 would have a direct correlation with the vegetation coverage and their active share in it. However, for 36 years, their active share in the vegetation coverage remained unchanged—amounting to 0% - 20%. Of course, in these years, the decrease in the number of mesophyte plants led to an increase in the number of plant communities, in which the proportion of vegetation coverage of mesophyte group is insignificant—0% - 5%. Despite the drought, the active part of the vegetation cover of mesophytic invasive species, such as Poa bulbosa, is consistently maintained.展开更多
In central part of Iraq within the vicinity of Karbala-Najaf, two cliffs called ＂Tar Al-Say＇ed＂ and ＂Tar Al-Najaf＂ form conspicuous geomorphological forms between the Mesopotamia Plain and the Western and Souther...In central part of Iraq within the vicinity of Karbala-Najaf, two cliffs called ＂Tar Al-Say＇ed＂ and ＂Tar Al-Najaf＂ form conspicuous geomorphological forms between the Mesopotamia Plain and the Western and Southern Deserts. The top surface between the two cliffs （tars） is covered by alluvial fan sediments, laid down by A1-Khir Valley when merging in a large depression due to the drop in the gradient of the valley. Consequently, the depression was divided into two parts, to the left is called Al-Razzazah Depression, whereas to the right is called Bahir Al-Najaf. This affected the course of the River Euphrates. The deposition stopped due to an uplift movement which caused the elevation of the two cliffs which are covered by alluvial fan sediments. The two cliffs had and are still suffering from retreating, due to lateral erosion by wave actions in Al-Razzazah Depression. Springs located along a straight line, sag pond, deflected drainage, shutter ridges and pressure ridges can be noticed in the area. The age of both cliffs is estimated to be upper Late Pleistocene--early Holocene.展开更多
基金supported by the National Natural Sciences Foundation of China[Grant No:41872048,41372061,40972038]financial support from China Scholarship Council(No 201806010080).
文摘To analyze the composition and structure of the pale blue outcrop from the UBC Cliffs and research the environmental significance of aerinite recorded in the sediments, mineral composition, bulk chemical composition and structural analyses were carried out by means of X-ray diffraction(XRD), field emission scanning electron microscope(FESEM), transmission electron microscope(TEM), electron microprobe analysis(EMPA) and X-ray fluorescence spectra(XRF). Quartz, feldspar, mica, chlorite and aerinite as well as a small amount of amphibole, calcite, clinopyroxene, rutile, perovskite and apatite are recorded in the sediments. It is reported for the first time that the aerinite occurs in a high latitude area and in sediments paragenetic with mica and chlorite. The large span in grain size shows a typical characteristic of fluvioglacial sediments. Geochemistry characteristics(CIA, CIW, PIA, WIP and ICV) verify that there is virtually no chemical weathering. Mineralogy and geochemistry features of the UBC Cliffs sediments indicate that aerinite is accommodate to the high latitude and cold, dry climate. As the sediments show high similarity to those of their provenance, they have great significance in the identification of the forming condition and origin of the aerinite.
文摘A composite fall-slippage model is proposed in this study for the Tertiary sedimentary coastal cliffs of Varkala in the western coastal tract of Peninsular India which are retreating landwards due to the combination of several factors.The fall model in the present study accounts both spring seepage and wave action,resulting in undercutting and this fall affects only the topmost laterite and the just below sandstone in the cliff.Slippage in this area affects all the litho-units and hence the geologic characteristics of all the litho-units are considered for developing the slippage model.This mathematically derived model can be used in other cliffs exhibiting the same morphology as well as the one controlled by the same influencing factors.This model differs from other models in incorporating multi-lithounits as well as multi-notches.Varkala cliffs form a part of the aspiring geopark in the Global Geopark Network and hence a study on the cliff recession is a pressing requirement.
文摘This work presents the behavior of Segou sandstones in the laboratory and in the field conditions. Four types of sandstone are collected in the northern part of the Madina Kouta basin (eastern Senegal). These types of specimens are the white sandstones, the red sandstones, the purple sandstones and the sandstones with intercalation of pelites. Uniaxial tests are carried out on these specimens of sandstones. The Young Moduli (E) and the Uniaxial Compression Strengths (Rc) are higher for the white sandstone. Values of the mechanical parameters decrease slightly for red sandstones due to an increase of the amount of pelites in the composition of the rock. Decrease of mechanical parameters is more important for the purple facies due to an important network of fractures. The facies with weaker characteristics corresponds to the sandstones with intercalation of pelites. This is due to the soft nature of the pelites. The slope stability of the Cliff sides depends also on to these characteristics.
基金the support provided by the Laboratory of Applied Research in Engineering Geology, Geotechnics, Water Sciences, and Environment, Setif 1 University, Algeria
文摘Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation.This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast coast of Algeria by identifying the key factors contributing to rockfall occurrence.We employed a combination of kinematic analysis,Matterocking method,and 3D trajectory simulations to determine zones that are susceptible to rockfall mobilization.By using a probabilistic and structural approach in conjunction with photogrammetry,we identified the controlling factors.The kinematic analysis revealed the presence of five discontinuity families,which indicated both plane and wedge failure modes.The 3D trajectory simulations demonstrated that the falling blocks followed the stream direction.We then validated the susceptibility maps generated from the analysis using aerial photos and historical rockfall events.The findings of this study enhance our understanding of rockfall phenomena and provide valuable insights for the development of effective strategies to mitigate rockfall hazards.
文摘White puffy clouds drift past a bungalow facing a deep valley and a towering peak beyond it.Chirps of birds animate the idyllic scene without shattering its serenity.The bungalow with a wood-plank roof and mud walls is featured in a video clip that Mouse Labo posted online on April 13.
文摘Just as the cliff serves as a demarcation between two different worlds, there seems to the protagonist in The Catcher in the Rye the dichotomies between innocence and corruption, children and adults. While these dualisms are projected in the story, they are also deconstructed and the characterization of Holden clearly shows the instability of those dualisms.
文摘在美国,社会经济快速发展,新潮词语层出不穷,其中包括一部分为数不少的简写词。现介绍一些如下: 1.BF best friend(最好的朋友)的简写。青年人喜欢交友,言谈中也是三句话不离“我最好的朋友”。为简便起见,干脆简称BF。如: Are you there for your BF when he gets intotrouble?当你最好的朋友生活不顺时,你在他身边吗?
基金The National Natural Science Foundation of China under contract Nos 41071006 and 40676052the Jiangsu Natural Science Foundation under contract No. BK2010050the Research Fund for the Doctoral Program of Higher Education of China under contract No.20100091110011
文摘The North Branch, separated by the Chongming Island, was once the main channel in the estuary of the Changjiang River. Reclamation and a decrease in runoffto the North Branch had led to the narrowing and shallowing of the channel. The Yuantuojiao Point is located at the intersecting point connecting the North Branch of the Changjiang River and the Jiangsu coastline. Erosion cliffs are developed between the typical silty-muddy tidal flat and the salt marsh occupied by Spartina alterniflorea, and this has changed rapidly over the past few years. The sediment grain size analysis results of the surficial and two core samples indi- cate that the Yuantuoiiao Point tidal fiat experienced continuous accretional processes. Based upon 137Cs analysis results of the YT and YY Cores sampled from the tidal flat at the Yuantuojiao Point, the average sed- imentation rate of the YT Core was 2.30 cm/a from 1963 to 2007, and 2.38 cm/a from 1954 to 2007 for the YY Core. The sedimentation rates of both core locations have declined since the 1960s corresponding to the seaward reclamation at the Yuantuojiao Point. The average sedimentation rates at the Yuantnojiao Point were similar to that of the silty-muddy tidal flat at the northern ]iangsu coast, but lower than that of the south of the Changjiang River Estuary. According to field morphological investigations from 2006 to 2008 on the salt marsh at the Yuantuojiao Point, cliffs retreated markedly by storm surges and disappeared gradu- ally because of the rapid sedimentation on the silty-muddy tidal flat. The maximum annual retreat reached 10 m. The recent sedimentation and morphological changes of the Yuantuojiao Point tidal flat not only displayed the retreat of the salt marsh and the disappearance of cliffs, but also was accompanied by rapid sedimentation of the silty-muddy tidal flat and the salt marsh, indicating the responses to the tidal currents, storm surges, Spartina alterniflorea trapping sediments and large-scale reclamation. The sediment grain size and their trends, southward coastal flow, and sandspits of the longshore bars suggest that the main sediment source at the Yuantuoijao Point, estuary of the North Branch was possibly from the Changjiang River before 1958, since then, it has been from the south of the submarine radial sand ridges of the southern Huanghai Sea （Yellow Sea）.
基金supported by the National Science Foundation of China (No.40976057)the State Oceanic Administration of China (No.908-02-03-04)
文摘Based on the field surveys and repeated cross-profile observations combined with the comparison of many years’ topog-raphic maps,this study shows the spatial variability and varying patterns of coastal erosion along the west coast of the Taiwan Strait.Regional differentiation in the Meso-Cenozoic coastal tectonics determined the irregular coastline and geological background for large-scale coastal erosion distribution.The intensity of coastal erosion on the west side of the Taiwan Strait is mild in the northern region,severe in the central region and modest in the southern region.The beaches along the coast are mainly backed by dunes,sea-walls or cliffs.The dunes and beaches show periodic erosion and recovery along the coast adjacent to river mouths,while persistent retreat of frontal dunes and beaches tends to occur in other areas.The beach erosion occurs mainly in front of seawalls.Due to the low strength of the unconsolidated sediment the soft cliffs suffer the severest coastline recession.Sea level rise and river sediment discharge reduction are main causes of coastal erosion.Storm surge is common in the studied area and plays an important role in the progress of coastal erosion.Human activities including coastal constructions and sand mining also tend to interfere strongly with the balance of sediment budget in some coastal cells.
基金The National Natural Science Foundation of China under contract No.41306051the Natural Science Foundation of Fujian Province of China under contract No.2015J01625
文摘A model for calculating the erosion distance of soft sea cliff under wave loading is established based on the erosion mechanism of soft sea cliff under wave loading and for considering wave hydrodynamic and sea cliff material parameters.The model is verified,and the parameters are regressed using an indoor flume experiment.The erosion distances of the sea cliff in the northeast of the Pingtan Island are calculated by the model,and the results are compared with the measured data.The maximum erosion occurs in static water level,the location of the maximum erosion moves up as the wave continues,and the erosion stops when the wave lasts for a period of time.The erosion does not occur until the wave height exceeds a critical value; however,the contribution of large waves to the erosion is not relatively substantial.The calculated erosion distances at two places in the northeast of Pingtan Island are 0.32 m and 0.26 m.
文摘美国专家路易·克鲁在批改一位中国学生的英语作文时,将其中描写山景的一个句于In front.it was the sharp slope of a cliff改成:Thefront cliff sloped sharply.同一个 slope,由名词改为动词,前后两个句子的结构和气势便立时大不一样.在现代英语中,越来越多的名词被当作动词使用,它们往往都能收到句式简炼,形象逼真的修辞效果。试看下面两个例句: Investigation fathered the baby on him.
基金financed in part from state funds allocated to science (Project No.N30509732/3259)
文摘Rocky habitats are regarded as biodiversity hot-spots. Along with high species diversity, diverse ecological relationships can be observed in these habitats. Large groups of bird species use rocks in various ways： as perching/roosting sites, breeding or foraging habitats, information exchange sites, display arenas or as sources of minerals and water. Because of the inaccessibility of these environments, their role and importance to animals has been underestimated. We evaluated the use of rocky habitats by birds in the Tatra Mountains （49°13′N; 19°57′E, Carpathians, central Europe）. Rocky habitats were used by 29 bird species, eight of which used cliffs directly （i.e. for nesting, foraging or resting）. The number of species recorded as using cliffs was correlated with the surface area of the cliff face. A total of 2o forms of rocky habitat use were recorded, in five behavioural categories： vocalization, foraging, perching, flight and nesting. Prevailing behaviours were flying by a rock face, circling above the face, and vocalization on a tree/shrub growing next to a rock. Rocks provide a nesting habitat for specialized petrophilic species and permit the existence of numerous ecological relations between species and habitats. The results of this study show that rocky habitats support the diversity of ecological relationships.
基金Project(2010BAK67B16) supported by the National Science and Technology Pillar Program during the 11th Five-Year Plan Period of China
文摘Cliff deformation behavior after conservation is of great significance for evaluating the conservation effect and discovering the dynamical law of soil. Modeling on deformation behavior is beneficial to the quantitative evaluation of interactions between soil mass and structures as well as the forecast. Based on cliff conservation engineering of Jiaohe Ruins （the largest raw soil heritage site in the world）, data of horizontal deformation of the upper cliff were obtained by using Nanrui-made NDW-50 displacement device （precision： 0.01 mm, frequency： 15 min^-l）. Regression analysis indicates that deformation behavior models include exponential growth, linear growth and parabolic growth types, while daily deformation presents more intense periodicity （24 h）. The deformation is less than 1.5 mm during monitoring period, which has no impact on the stability of cliff. Deformation behavior provides the mutual duress and interaction between soil and engineering intervention. In addition, deformation mode attaches tensely to the damage pattern of the cliff. The conclusions are of importance to the stability evaluation of the carrier along Silk Road.
基金Funded by China Postdoctoral Science Foundation (No. 2005037548).
文摘Based on site studies, historical literature investigation and academic communication, this work aims to dig out the cultural significance in architectural and religious aspects conveyed in cliff carvings in the Bashu region. After casting a glance at the origin and evolution of Bashu culture and religion mainly involving Daoism and Buddhism recorded in forms of cliff carvings, we concentrated on discovering the national, regional and folk architectural characters implicated in cliff carvings at different sites within the Bashu region. The cliff carvings in this region vividly depicted the evolution of the architectural culture hereof. The essence of their religious and architectural connotations can be good stuff to be input in today’s architectural design philosophy.
文摘The aim of this work is to map the susceptibility of sites to landslides. To assess the susceptibility of the zone, GIS techniques were used. Susceptibility factors are selected and split into two groups: active and passive factors. Passive factors regroup all the intrinsic conditions existing on the field at all times. The active factors or triggering factors are present sporadically and are added to the passive factors to trigger a landslide. With the weighted overlay method using ArcGIS?, four scenarios have been developed. A first scenario where only passive factors are combined and three scenarios for which we have for each scenario the passive factors combined with an active factor. With these different scenarios, five levels of susceptibility are obtained in the zone. These levels range from very low to very high susceptibility. For the different scenarios, the results show that the zone consists mainly of very low to low susceptibility with at least 61% of the area, followed by moderate susceptibility (23.54% to 38.24%) and last land with high susceptibility to very high with less than 1% of the surface. Fields with high to very high susceptibility are located on the slopes of the hills. Among the active factors, only the rainfall significantly modifies the percentage of land susceptible to landslide but remains in the field of moderate susceptibility. The predicted susceptibilities are closer to the observed landslides around the Thies Cliff than to the Dias Horst.
文摘A decrease in the amount of precipitation is observed on average 18 - 20 mm compared with the periods before the Aral crisis and the average annual temperature rise over the long-term period is 2.0°C in the Central part of Ustyurt. An increase in the Si index meaning an increase in the degree of drought every ten-flight is clearly expressed in the months March-July. Data Analysis 1981-2017 shows that within 36 years the species diversity in the monitoring sites of Kabanbay decreased by 2 - 3 times. In 1981 the number of species fluctuated between the values of 9 - 50, and in 2017 this figure is 4 - 17. The results of the analysis show that the forecast indicators of the old-current state (1981) of the vegetation coverage and number of species were stable or had tendencies with a low regressive character (r2 = 0.01). However, the current-state (2017) of the vegetation coverage and the species composition of the monitoring plots showed a low progressive trend (r2 = 0.03), i.e. in the future, the formation of plant communities with low vegetation coverage and species composition has a dominant status. The results show that in 1981, 65% - 80% of the species composition of plant communities consisted of halophyte and xerophyte groups. In 2017, this figure reaches 80% - 100%, i.e. this claims to increase xerophytization and halophytization of territories. An interesting fact is established with mesophyte group. In general, theoretically, the decrease in the number of mesophyte group of plants for 1981-2017 would have a direct correlation with the vegetation coverage and their active share in it. However, for 36 years, their active share in the vegetation coverage remained unchanged—amounting to 0% - 20%. Of course, in these years, the decrease in the number of mesophyte plants led to an increase in the number of plant communities, in which the proportion of vegetation coverage of mesophyte group is insignificant—0% - 5%. Despite the drought, the active part of the vegetation cover of mesophytic invasive species, such as Poa bulbosa, is consistently maintained.
文摘In central part of Iraq within the vicinity of Karbala-Najaf, two cliffs called ＂Tar Al-Say＇ed＂ and ＂Tar Al-Najaf＂ form conspicuous geomorphological forms between the Mesopotamia Plain and the Western and Southern Deserts. The top surface between the two cliffs （tars） is covered by alluvial fan sediments, laid down by A1-Khir Valley when merging in a large depression due to the drop in the gradient of the valley. Consequently, the depression was divided into two parts, to the left is called Al-Razzazah Depression, whereas to the right is called Bahir Al-Najaf. This affected the course of the River Euphrates. The deposition stopped due to an uplift movement which caused the elevation of the two cliffs which are covered by alluvial fan sediments. The two cliffs had and are still suffering from retreating, due to lateral erosion by wave actions in Al-Razzazah Depression. Springs located along a straight line, sag pond, deflected drainage, shutter ridges and pressure ridges can be noticed in the area. The age of both cliffs is estimated to be upper Late Pleistocene--early Holocene.
