检索结果-南通市图书馆

Hydrological and sediment connectivity under Freeze-thaw meltwater compound erosion conditions on a loessal slope

International Soil and Water Conservation Research 2023年第2期11卷 402-411页

作者： Tian Wang Jingsi Li Jingming Hou Yongyong Ma Peng Li Yu Tong Jing Li Zhanbin Li State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China Xi'an University of TechnologyXi'an710048ShaanxiChina Key Laboratory of National Forestry Administration on Ecological Hydrology and Disaster Prevention in Arid Regions Xian University of TechnologyXi'an 710048ShaanxiChina Shaanxi Province Institute of Water Resources and Electric Power Investigation and Design Xi'an710005ShaanxiChina

Freeze-thaw processes can influence hydrology,soil erosion,and morphological development by altering the connectivity between active pathways of water and sediment transport.Concentrated flow experi-ments were conducted involving frozen,shallow thawed,and unfrozen soil slopes under 1,2,and 4 L/min runoff rates at a temperature of approximately 5℃.In this study,hydrological connectivity was analysed via the simplified hydrological curve and relative surface connection function.Sediment con-nectivity was analysed via the sediment structure connectivity and sediment functional connectivity.Results indicated that hydrological connectivity was greatest on frozen slopes(FS),followed by shallow thawed slopes(STS),and unfrozen slopes(UFS)given a constant flow rate.Hydrological connectivity increased with increasing runoff rate for each Freeze-thaw condition.Freezing condition and runoff rate exhibited a positive response to the hydrological connectivity.Sediment structure connectivity increased with increasing runoff rate for each slope condition.The ordering of sediment structure connectivity across Freeze-thaw condition was that FS was greater than STS while STS was greater than UFS inde-pendent of flow rate.Sediment functional connectivity included longitudinal,lateral,and vertical con-nectivity components.Sediment longitudinal and vertical connectivity indicated a trend of first increasing and then decreasing under the different runoff rates and Freeze-thaw conditions.For a given runoff rate,the ordering of sediment longitudinal and vertical connectivity across Freeze-thaw condition was that FS was greater than STS while STS was greater than UFS.Sediment lateral connectivity exhibited a trend of first decreasing and then stabilizing.The ordering of sediment lateral connectivity across Freeze-thaw condition was that UFS was greater than STS while STS was greater than FS.FS could more easily reach longitudinal and vertical penetration.Sediment longitudinal and vertical connectivity rates demonstrated increasing trends

关键词： Freeze-thaw Runoff Erosion Structureand functional connectivity Loessal slope

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transport mechanism of eroded sediment particles under Freeze-thaw and runoff conditions

引用

Journal of Arid Land 2022年第5期14卷 490-501页

作者： WANG Tian LI Peng HOU Jingming TONG Yu LI Jing WANG Feng LI Zhanbin State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi'an University of TechnologyXi'an 710048China Key Laboratory of National Forestry Administration on Ecological Hydrology and Disaster Prevention in Arid Regions Xi'an University of TechnologyXi'an 710048China

Hydraulic erosion associated with seasonal Freeze-thaw cycles is one of the most predominant factors,which drives soil stripping and transportation.In this study,indoor simulated meltwater erosion experiments were used to investigate the sorting characteristics and transport mechanism of sediment particles under different Freeze-thaw conditions(unfrozen,shallow-thawed,and frozen slopes)and runoff rates(1,2,and 4 L/min).Results showed that the order of sediment particle contents was silt>sand>clay during erosion process on unfrozen,shallow-thawed,and frozen slopes.Compared with original soils,clay and silt were lost,and sand was deposited.On unfrozen and shallow-thawed slopes,the change of runoff rate had a significant impact on the enrichment of clay,silt,and sand particles.In this study,the sediment particles transported in the form of suspension/saltation were 83.58%–86.54%on unfrozen slopes,69.24%–84.89%on shallow-thawed slopes,and 83.75%–87.44%on frozen slopes.Moreover,sediment particles smaller than 0.027 mm were preferentially transported.On shallow-thawed slope,relative contribution percentage of suspension/saltation sediment particles gradually increased with the increase in runoff rate,and an opposite trend occurred on unfrozen and frozen slopes.At the same runoff rate,Freeze-thaw process had a significant impact on the relative contribution percentage of sediment particle transport via suspension/saltation and rolling during erosion process.The research results provide an improved transport mechanism under Freeze-thaw condition for steep loessal slopes.

关键词： Freeze-thaw runoff conditions erosion process sediment particles transport mechanism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Correlation and interaction between temperature and Freeze-thaw in representative regions of Antarctica

引用

International Journal of Digital Earth 2022年第1期15卷 2296-2318页

作者： Dong Liang Huadong Guo Qing Cheng Lu Zhang Lingyi Kong Key Laboratory of Digital Earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijingPeople’s Republic of China University of Chinese Academy of Sciences BeijingPeople’s Republic of China International Research Center of Big Data for Sustainable Development Goals BeijingPeople’s Republic of China School of Computer Science China University of GeoscienceWuhanPeople’s Republic of China

As the most sensitive and direct indicator of global climate change,the freezing and thawing of the Antarctic ice sheet is of great significance for research on surface mass and energy balance.In this study,four representative regions in Antarctica were selected and correlation analysis,Granger causality testing,and cluster analysis were applied to comprehensively analyze the correlation and response of spatiotemporal variation in Freeze-thaw and temperature.The conclusions are as follows.(1)In the Antarctic Peninsula,a phenomenon was demonstrated that the summer shifts rearward.Hotter December and colder March temperatures were observed in the Amery Ice Shelf and Queen Maud Land.(2)The Antarctic Peninsula featured the most severe degree of melting among the four regions,with the largest melt area in the past 30 years appearing during the 2015/2016 season.However,the number of melt days in most areas of the Antarctic Peninsula was observed to have decreased.(3)There is a strong correlation between the Freeze-thaw state of the Antarctic ice sheet and temperature,as well as spatial differences among regions,but the data were clustered at different time scales.

关键词： Antarctic ice sheet Big Earth Data Freeze-thaw microwave remote sensing snowmelt temperature

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Shear behavior of ultrafine magnetite tailings subjected to Freeze-thaw cycles

引用

International Journal of Mining Science and Technology 2019年第4期29卷 609-616页

作者： Chong Wei Derek B.Apel Yunhai Zhang School of Mining and Petroleum Engineering University of AlbertaEdmontonAlberta T6G 2R3Canada School of Resources and Safety Engineering Central South UniversityChangsha 410083China

To study the shear behavior of the ultrafine magnetite tailings subjected to Freeze-thaw cycles,unconsolidated-undrained shear tests were conducted on ultrafine-grained tailings that were subjected to 1-11 cycles of Freeze-thaw and defined as a type of clayey silt under confining pressures of 100,200,and 300 kPa.Taking the number of Freeze-thaw cycles,cooling temperature,initial dry density,and moisture content as the four main influencing factors of shear behavior of the tailings samples,the shear stress-strain curve,compression modulus,failure strength,cohesion,and internal friction angle were measured.The results show that the Freeze-thaw cycle has an obvious weakening effect on the shear behavior of the tailings material,and the shear mechanical parameters are affected by a combination of confining pressure,Freeze-thaw cycle condition,and initial physical-mechanical properties of the tailings samples.Through the microstructural analysis of the tailings samples subjected to Freeze-thaw cycles,it shows that the Freeze-thaw cycle mainly affects the porosity,bound water,and arrangement of the tailings particles.Subsequently,the macroscopic changes in shear strength indexes emerge,and then the stability of the tailings dam will decrease.

关键词： Ultrafine magnetite tailings(UMT) Freeze-thaw cycle Shear behavior Triaxial shear test

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Freeze-thaw cycles and associated geomorphology in a post-glacial environment:current glacial,paraglacial,periglacial and proglacial scenarios at Pico de Orizaba volcano,Mexico

引用

Journal of Mountain Science 2024年第6期21卷 1954-1977页

作者： Víctor SOTO Carlos M.WELSH R. Kenji YOSHIKAWA Hugo DELGADO GRANADOS Centro de Ciencias de la Tierra Universidad VeracruzanaCircuito Gonzalo Aguirre BeltránS/NZona Universitaria91090XalapaMéxico Water and Environmental Research Center University of Alaska FairbanksFairbanksAlaska 99775USA Instituto de Geofísica Universidad Nacional Autónoma de MéxicoCiudad de México 04150México Department of Earth and Environmental Sciences Ludwig Maximilians UniversitätMunich 80333Germany

The glacial history of Pico de Orizaba indicates that during the Last Glacial Maximum,its icecap covered up to~3000 m asl;due to the air temperature increasing,its main glacier has retreated to 5050 m asl.The retraction of the glacier has left behind an intense climatic instability that causes a high frequency of Freeze-thaw cycles of great intensity;the resulting geomorphological processes are represented by the fragmentation of the bedrock that occupies the upper parts of the mountain.There is a notable lack of studies regarding the fragmentation and erosion occurring in tropical high mountains,and the associated geomorphological risks;for this reason,as a first stage of future continuous research,this study analyzes the freezing and thawing cycles that occur above 4000 m asl,through continuous monitoring of surface ground temperature.The results allow us to identify and characterize four zones:glacial,paraglacial,periglacial and proglacial.It was found that the paraglacial zone presents an intense drop of temperature,of up to~9℃ in only sixty minutes.The rock fatigue and intense Freeze-thaw cycles that occur in this area are responsible for the high rate of rock disintegration and represent the main factor of the constant slope dynamics that occur at the site.This activity decreases,both in frequency and intensity,according to the distance to the glacier,which is where the temperature presents a certain degree of stability,until reaching the proglacial zone,where cycles are almost non-existent,and therefore there is no gelifraction activity.The geomorphological processes have resulted in significant alterations to the mountain slopes,which can have severe consequences in terms of risk and water.

关键词： Freeze-thaw Gelifraction Mountain mechanical erosion Periglacial geomorphology Postglacial scenarios

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Study on tensile damage characteristics of sandstone under Freeze-thaw cycles

引用

Research in Cold and Arid Regions 2021年第5期13卷 379-393页

作者： Hui Liu YeHui Yun Long Jin JiangHao Lin Yao Zhang Yong Luo JianXi Ren College of Architecture and Civil Engineering Xi'an University of Science and TechnologyXi'anShaanxi 710054China CCCC First Highway Consultants Co.LTD Xi'anShaanxi 710075China

The meso-structure of sandstone has a significant effect on its mechanical properties under external loads.In this paper,by taking two types of sandstone with different grain sizes as the study objects,the effects of grain size and Freeze-thaw cycles on tensile strength and damage mode of sandstone are analyzed using a combination of laboratory tests,theoretical analysis,and numerical calculation.The Brazilian splitting tests are carried out on sandstone samples subjected to Freeze-thaw cycles.The results show that:(1)The Brazilian splitting mode of the fine-grained sandstone is dominated by the central fracture,whereas that of the coarse-grained sandstone is controlled by a noncentral fracture.(2)The Freeze-thaw cycles aggravate the initial damage of sandstone,and the cumulative Freeze-thaw damage has a greater impact on the Brazilian splitting damage mode of the coarse-grained sandstone than on the fine-grained sandstone.(3)The numerical analysis software RFPA2D system can simulate the Brazilian splitting failure process of the two types of sandstone with varying grain sizes under different Freeze-thaw cycles.It is shown to be an effective method to reveal the tensile failure process and deterioration mechanism of sandstone under Freeze-thaw cycling.(4)The formation mechanisms of the two splitting modes are analyzed according to the energy principle.The energy release of coarse-grained sandstone forms a noncentral splitting mode along the rock sample internal weak structural plane,whereas the fine-grained sandstone sample's energy accumulates in the rock sample center and releases it instantaneously at its center,showing the failure mode of central splitting.In addition,based on damage mechanics theory,the damage evolution equation of sandstone subjected to Freeze-thaw cycles under tension is established,and the influence of energy release and dissipation on the sandstone's tensile properties is quantitatively analyzed.

关键词： Freeze-thaw sandstone damage mode energy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of Freeze-thaw cycle and dry-wet alternation on slope stability

引用

Research in Cold and Arid Regions 2019年第2期11卷 159-172页

作者： YaLing Chou LiYuan Sun BaoAn Li XiaoLi Wang School of Civil Engineering Lanzhou University of Technology Jiangsu JiaoTong Traffic Design Research Institute Co. Ltd.

The typical loess on high slopes along the BaoLan High-speed Rail, China, was selected as the research object. The influence of the Freeze-thaw cycle and dry-wet alternation on the shear-strength parameters of the unsaturated loess was investigated by laboratory experimental methods. Moreover, the temperature field, seepage field, and stability of slopes with different gradients were simulated under the effect of the Freeze-thaw cycle and dry-wet alternation by using the geotechnical analysis software Geo-Studio. The research results showed(1) when the Freeze-thaw cycle was repeated on the slope, with the frozen depth increasing, the melted depth did the same; besides, the closed loop of isotherms formed on the slope;(2) under the action of dry-wet circulation, the negative pore-water pressure and volumetric water content showed an upward tendency. However, owing to the different slope gradients, rainfall infiltration was not the same. As time went by, the differences of the negative pore-water pressure and volumetric water content between the slopes of different gradients continued to increase;(3) with the Freeze-thaw cycle and dry-wet alternation increasing, the slope-safety factor decreased. Especially in the early period, the slope-safety factor changed remarkably. For slopes undergoing Freeze-thaw action, the slope-safety factor was negatively correlated with the gradient. However, with regard to slopes undergoing dry-wet alternation, the result became more complex because the slope-safety factor was related to both seepage strength and slope grade. Accordingly, further research is needed to study the effect of seepage strength and slope grade on the stability of loess slopes.

关键词： Freeze-thaw action dry-wet alternation temperature field seepage field slope stability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Frozen bean curd-inspired xenogeneic acellular dermal matrix with triple pretreatment approach of freeze–thaw,laser drilling and ADSCs pre-culture for promoting early vascularization and integration

引用

Regenerative Biomaterials 2022年第1期9卷 687-703页

作者： Xing Huang Zhu Zhu Lin Lu Rui Jin Di Sun Xusong Luo Department of Plastic and Reconstructive Surgery Shanghai 9th People’s HospitalShanghai Jiao Tong University School of MedicineShanghai 200011PR China Shanghai Key Lab of Tissue Engineering Shanghai 9th People’s HospitalShanghai Jiao Tong University School of MedicineShanghai 200011PR China

Xenogeneic acellular dermal matrix(ADM)is widely used in clinical practice given its good biocompatibility and biomechanical properties.Yet,its dense structure remains a hindrance.Incorporation of laser drilling and pre-culture with Adipose-derived stem cells(ADSCs)have been attempted to promote early vascularization and integration,but the results were not ideal.Inspired by the manufacturing procedure of frozen bean curd,we proposed a freeze–thaw treatment to enhance the porosity of ADM.We found that the ADM treated with-80℃3Rt-30℃3R had the largest disorder of stratified plane arrangement(deviation angle 28.6%)and the largest porosity(96%),making it an optimal approach.Human umbilical vein endothelial cells on freeze–thaw treated ADM demonstrated increased expression in Tie-2 and CD105 genes,proliferation,and tube formation in vitro compared with those on ADM.Combining freeze–thaw with laser drilling and pre-culture with ADSCs,such tri-treatment improved the gene expression of proangiogenic factors including IGF-1,EGF and vascular endothelial growth factor,promoted tube formation,increased cell infiltration and accelerated vascularization soon after implantation.Overall,freeze–thaw is an effective method for optimizing the internal structure of ADM,and tri-treatments may yield clinical significance by promoting early cell infiltration,vascularization and integration with surrounding tissues.

关键词： Freeze-thaw xenogeneic acellular dermal matrix vascularization early integration

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effects of freeze–thaw cycles on soil N_2O concentration and flux in the permafrost regions of the Qinghai–Tibetan Plateau

引用

Research in Cold and Arid Regions 2018年第1期10卷 69-79页

作者： ShengYun Chen Qian Zhao WenJie Liu Zhao Zhang Shuo Li HongLin Li ZhongNan Nie LingXi Zhou ShiChang Kang Qilian Shan Station of Glaciology and Ecologic Environment State Key Laboratory of Cryospheric ScienceNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China Institute of Tropical Agriculture and Forestry Hainan UniversityHaikouHainan 570228China State Key Laboratory of Plateau Ecology and Agriculture Qinghai UniversityXiningQinghai 810016China Department of Economic Development JobsTransport and ResourcesPrivate Bag 105Hamilton VIC 3300Australia Chinese Academy of Meteorological Sciences Beijing 100081China University of Chinese Academy of Sciences Beijing 100049China

Nitrous oxide(N_2 O) is one of the most important greenhouse gases in the atmosphere; freeze–thaw cycles(FTCs) might strongly influence the emission of soil N_2 O on the Qinghai–Tibetan Plateau(QTP). However, there is a lack of in situ research on the characteristics of soil N_2 O concentration and flux in response to variations in soil properties caused by FTCs.Here, we report the effect of FTC-induced changes in soil properties on the soil N_2 O concentration and flux in the permafrost region of the higher reaches of the Shule River Basin on the northeastern margin of the QTP. We measured chemical properties of the topsoil, activities of soil microorganisms, and air temperature(AT), as well as soil N_2 O concentration and flux, over an annual cycle from July 31, 2011, to July 30, 2012. The results showed that soil N_2 O concentration was significantly affected by soil temperature(ST), soil moisture(SM), soil salinity(SS), soil polyphenol oxidase(SPO), soil alkaline phosphatase(SAP), and soil culturable actinomycetes(SCA), ranked as SM>SS>ST>SPO>SAP>SCA, whereas ST significantly increased soil N_2 O flux, compared with SS. Overall, our study indicated that the soil N_2 O concentration and flux in permafrost zone FTCs were strongly affected by soil properties, especially soil moisture, soil salinity, and soil temperature.

关键词： Freeze-thaw cycles soil environment N2O

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Freeze-thaw performance of chemically stabilized natural and recycled highway materials

引用

Research in Cold and Arid Regions 2015年第5期7卷 482-491页

作者： Tuncer B.Edil Bora Cetin Department of Civil and Environmental Engineering University of Wisconsin College of Engineering University of Georgia

This article provides an overview of several previous studies that investigated the stiffness and strength performance of chemically stabilized roadway materials under winter conditions （Freeze-thaw cycling）. The objective of this research was to understand the behavior of different materials stabilized with different type of binders when they were subjected to Freeze-thaw cycling. Nine different materials including natural soils （organic soil, clay, silt, sand, and road surface gravel）, reclaimed pavement material, and recycled asphalt pavement stabilized with nine different binders （five different fly ashes, lime, cement, lime kiln dust, cement kiln dust） were discussed. This article investigated how the volume, resilient modulus and unconfined compressive strength of soils/materials stabilized with different binders change in response to Freeze-thaw cycling. Overall, the review results indicate that the stiffness and strength of all stabilized materials decrease somewhat with Freeze-thaw cycling. However, the reduced strength and stiffness of stabilized materials after Freeze-thaw cycling was still higher than that of unstabilized-unfrozen original soils and materials. In addition, materials stabilized with cement kiln dust provided the best performance against Freeze-thaw cycling.

关键词： Freeze-thaw soil stabilization cement fly ash lime

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：