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Formation mechanism of coal-rock gas accumulation transition zones 认领 引用
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作者 LI Guoxin ZHAO Qun +4 位作者 ZHANG Junfeng LIU Dan SUN Jian ZHOU Tianqi XIAO Yuhang 《Petroleum Exploration and Development》 SCIE 2026年第3期638-655,共18页
Research on hydrocarbon accumulation mechanism in coal-measure whole petroleum systems and coal-rock gas exploration has revealed that coal-rock gas occurs along coal-bearing strata and forms different reservoir types... Research on hydrocarbon accumulation mechanism in coal-measure whole petroleum systems and coal-rock gas exploration has revealed that coal-rock gas occurs along coal-bearing strata and forms different reservoir types with distinct geological characteristics in different structural regions,and that between primary coal-rock gas reservoirs and residual coal-rock gas reservoirs(i.e.,traditional shallow coalbed methane reservoirs),the gas-water relationship in the macroscopic pores and fractures of coal reservoirs gradually evolves in space,forming coal-rock gas accumulation transition zones with prominent features.Taking the coal-rock gas of the Carboniferous Benxi Formation in the central-eastern Ordos Basin,China,as an example,this study constructs the dynamic mechanism and mathematical models for the coal-rock gas accumulation transition zone by considering the dual-medium structure,stress sensitivity,and wettability variation of coal reservoirs.On this basis,the dynamic equilibrium among buoyancy,capillary force and hydrocarbon-generation expansion force is clarified.The results show that,under the geological background of uplift and reworking,the cleat fracture system and porosity-permeability properties of coal reservoirs are fundamental for the formation of the transition zone,the hydrocarbon-generation expansion force of coal rocks is an inherent determinant for the depth of the transition zone,and the spatial variation of coal rank and tectonic reworking intensity control the distribution of the transition zone.Numerical simulation results and practical exploration and development have demonstrated that,at the eastern margin of the Ordos Basin,the transition zone for medium-to high-rank coal-rock gas reservoirs in the Daning-Jixian area in the south is mainly buried at 130o-1800 m,while the transition zone for low-to medium-rank coal-rock gas reservoirs in the north occurs at a greater depth of 1500-2300 m.Through comprehensive investigation,the coal-rock gas accumulation zones at the eastern margin of the Ordos Basin are examined by hydrocarbon accumulation evolution analysis and spatial distribution prediction.Three continuous hydrocarbon accumulation evolution units are identified,i.e.deep coal-rock gas accumulation zone,coal-rock gas accumulation transition zone,and shallow coalbed methane accumulation zone.The research results deepen the understanding of accumulation mechanism and differential enrichment mechanism of coal-rock gas,and provide a theoretical basis for improving coal-rock gas classification and guiding favorable area evaluation and efficient exploration and development. 展开更多
关键词 coal-measure whole petroleum system coal-rock gas dynamic mechanism coal-rock gas accumulation transition zone Ordos Basin favorable area evaluation
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Global Assessment of the Cloud-Aerosol Transition Zone Using CALIPSO 认领 引用
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作者 Jaume RUIZ DE MORALES Josep CALBÓ +4 位作者 Josep-Abel GONZÁLEZ Hendrik ANDERSEN Jan CERMAK Julia FUCHS Yolanda SOLA 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2026年第2期321-335,I0001-I0003,共15页
The interactions between clouds and aerosols represent one of the largest uncertainties in assessing the Earth's radiation budget, highlighting the importance of research on the transition zone(TZ) within the clou... The interactions between clouds and aerosols represent one of the largest uncertainties in assessing the Earth's radiation budget, highlighting the importance of research on the transition zone(TZ) within the cloud-aerosol continuum.This study assesses the global distribution of TZ conditions, analyzes its optical characteristics, and determines the cloud or aerosol types most commonly associated with them, using the cloud-aerosol discrimination(CAD) score of the CloudAerosol Lidar with Orthogonal Polarization(CALIOP) instrument on the CALIPSO satellite. The CAD score classifies clouds and aerosols by the probability density functions of attenuated backscatter, total color ratio, volume depolarization ratio, altitude, and latitude. After applying several filters to avoid artifacts, the TZ was identified as those atmospheric layers that cannot be clearly classified as clouds or aerosols, layers within the no-confidence range(NCR) of the CAD score, and cirrus fringes. The optical characteristics of NCR layers exhibit two main clusters: Cluster 1, with properties between high-altitude ice clouds and aerosols(e.g., wispy cloud fragments), and Cluster 2, with properties between water clouds and aerosols at lower altitudes(e.g., large hydrated aerosols). Our results highlight the significant ubiquity of TZ conditions, which appear in 9.5% of all profiles and comprise 6.4% of the detected layers. Cluster 1 and cirrus-fringe layers predominate near the ITCZ and in mid-latitudes, whereas Cluster 2 layers are more frequent over the oceans along the central West African and East Asian coasts, where elevated smoke and dusty marine aerosols are common. 展开更多
关键词 cloud-aerosol transition zone twilight zone aerosol-cloud interactions CALIPSO cloud vertical structure
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Incorporating spatial autocorrelation into soil salinity models:Insights from the Minqin Oasis and its desert–oasis transition zone in Northwest China 认领 引用
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作者 ZHAO Dan YANG Xiya +3 位作者 GAO Yukun PAN Jing YOU Quangang XUE Xian 《Journal of Arid Land》 SCIE CAS CSCD 2026年第7期1135-1158,共24页
Remote sensing-based soil salinity inversion serves as a crucial approach for monitoring and assessment in arid regions.However,most existing models rarely account for the spatial autocorrelation(SAC)of soil salinity,... Remote sensing-based soil salinity inversion serves as a crucial approach for monitoring and assessment in arid regions.However,most existing models rarely account for the spatial autocorrelation(SAC)of soil salinity,which limits both their predictive accuracy and ability to capture spatial patterns.To address this gap,this study investigated the Minqin Oasis and its adjacent desert–oasis transition zone in Northwest China.Based on collected field soil samples and concurrently acquired Landsat-8 OLI remote sensing images in 2024,we incorporated characteristic bands reflecting SAC into conventional spectral indices.Through multi-band combination optimization and comparison of different models'predictive performance,we constructed an optimal soil salinity inversion model for the Minqin Oasis and its adjacent desert–oasis transition zone.The results demonstrated that incorporating SAC of soil salinity markedly improved model performance,with the Gradient Boosting Regression Trees(GBRT)model incorporating SAC(GBRT_SAC)achieving the best accuracy.Compared with the traditional spectral index-based GBRT model,the coefficient of determination(R2)increased by 7.320%,the root mean square error(RMSE)decreased by 20.230%,and the mean absolute percentage error(MAPE)decreased by 121.01%using the GBRT_SAC model.The soil salinity distribution derived from the GBRT_SAC model revealed pronounced spatial heterogeneity,with salinized areas covering approximately 1256.75 km2(36.170%of the total area).Soil salinity was jointly influenced by natural and anthropogenic factors.At the regional scale,soil type and vegetation type emerged as the dominant drivers shaping soil salinity patterns.In contrast,within the oasis interior,soil salinity was primarily driven by groundwater table regulated by irrigation,leading to surface salt accumulation through capillary rise.In the 1000 m desert–oasis transition zone,the explanatory power(q-value)of all environmental factors for spatial variation of soil salinity significantly increased,indicating a sensitive interface where hydrological and aeolian processes interact.Notably,although soil salinity was relatively lower in sandy areas,sand content emerged as the most influential factor in this region(q-value=0.483),effectively serving as a key indicator of the transitional environment.By introducing SAC-based features into soil salinity inversion models,this study provides a robust methodological framework and valuable data to support understanding and management of soil salinization in arid desert–oasis ecotone systems. 展开更多
关键词 soil salinization spatial autocorrelation(SAC) machine learning Gradient Boosting Regression Trees(GBRT) spatial heterogeneity GeoDetector desert–oasis transition zone
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Seismic evidence for a thickened mantle transition zone beneath the Kamchatka subduction zone 认领 引用 被引量：1
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作者 Qinghui Cui Yuanze Zhou +1 位作者 Yuan Gao Ran Cui 《Earthquake Science》 CAS CSCD 2025年第4期288-303,共16页
The structures of the mantle transition zone(MTZ)are of great significance for studying interactions of the subducted slab and deep mantle and related slab dynamics beneath subduction zones.Here by dense near-source S... The structures of the mantle transition zone(MTZ)are of great significance for studying interactions of the subducted slab and deep mantle and related slab dynamics beneath subduction zones.Here by dense near-source SdP sampling from a large global dataset,we image topographies of transition zone discontinuities such as the 410-km and 660-km discontinuities(410 and 660)beneath the Kamchatka and conduct cross-section comparisons with the seismicity.Compared with the IASP91 model,the 410 exhibits apparent uplifts of 45-65 km with an average of 55 km in a horizontal width of~130 km,corresponding to lowtemperature anomalies of 750-1083 K with an average of 916 K.In contrast,the 660 shows depressions of 15-37 km with an average of 25 km together with downward deflections in a width of~260 km,implying low-temperature anomalies of 161-397 K with an average of 268 K.Thus,we confirm a thickened MTZ with a thickness of 325-345 km around the cold descending Pacific slab.We suggest that topographic patterns of transition zone discontinuities imply a Pacific slab that has been significantly heated in the MTZ with broadened thermal effects on the 660.When considered along with other studies,we infer that the slab is possibly heated by hot mantle flows around the torn slab window extended to at least the MTZ range,thus inducing variations in thermal and rheological properties of the slab.Our seismic results can provide more insight into slab dynamics in the northwestern Pacific. 展开更多
关键词 Kamchatka subduction zone transition zone discontinuities heated Pacific slab N-th root slant stack
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Afforestation species and slope as key drivers of soil carbon sequestration in plantations of the tropical‑subtropical transition zone:a case study from Xishuangbanna,Southwest China 认领 引用 被引量：1
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作者 Shiqiang Wang Wei Han Sangui Yi 《Journal of Forestry Research》 SCIE EI CAS CSCD 2025年第6期31-44,共14页
Tree plantations in the tropical-subtropical transition zone(TSTZ)represent crucial ecological regions where diverse biomes converge.Investigating the carbon sequestration potential and dynamic changes within these pl... Tree plantations in the tropical-subtropical transition zone(TSTZ)represent crucial ecological regions where diverse biomes converge.Investigating the carbon sequestration potential and dynamic changes within these plantation ecosystems is of considerable ecological significance.However,the spatial distribution,driving factors,and underlying mechanisms of carbon sequestration in plantations in this region are poorly understood,thereby limiting accurate assessments of their carbon sequestration potential.This study examines four types of plantation forests located within the TSTZ on the Puwen forest farm of Xishuangbanna,China.Two slope gradients were established to quantify and compare the rate of carbon sequestration across these ecosystems.Using random forest modeling and structural equation modeling,the study identifies key environmental factors influencing the rate of carbon sequestration in the plantations.The results reveal substantial variation in DBH growth rates,biomass carbon sequestration,and soil organic carbon sequestration rates(RSOC)among the four forest types.Critical factors affecting RSOCinclude leaf nitrogen and phosphorus concentrations(LP),total soil nitrogen(STN),total soil phosphorus(STP),soil available phosphorus,and nitrogen concentration in ground surface litter.Among these,STN and STP exerted positive effects on RSOC,while LP is exerted negative.Overall,the concentration of soil carbon,nitrogen and phosphorus,along with the nitrogen and phosphorus levels in leaves,under different species and topographic slopes,play decisive roles in regulating soil carbon sequestration rates in tropical and subtropical plantations.This research provides support for vegetation protection and restoration in ecologically sensitive areas and watersheds,contributing to the enhancement of regional forest carbon sequestration capacity. 展开更多
关键词 Afforestation Impact factor Slope Soil organic carbon sequestration Tree species Tropicalsubtropical transition zone
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Sea ice classification in the Arctic transition zone using Haiyang-2B microwave scatterometer and radiometer data 认领 引用
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作者 Shiyu Wu Tingting Liu +3 位作者 Mohammed Shokr Ruibo Lei Fan Yang Yachao Li 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2025年第3期84-101,共18页
Loss of multiyear ice(MYI)is of great importance for Arctic climate and marine systems and can be monitored using active and passive microwave satellite data.In this paper,we describe an upgraded classification algori... Loss of multiyear ice(MYI)is of great importance for Arctic climate and marine systems and can be monitored using active and passive microwave satellite data.In this paper,we describe an upgraded classification algorithm using the data from the scatterometer and radiometer sensors onboard the Chinese Haiyang-2B(HY-2B)satellite to identify MYI and first-year ice(FYI).The proposed method was established based on K-means and fuzzy clustering(K-means+FC)and was used to focus on the transition zone where the ice condition is complex due to the highly commixing of MYI and FYI,leading to the high challenge for accurate classification of sea ice.The K-means algorithm was applied to preliminarily classify MYI using the combination of scatterometer and radiometer data,followed by applying fuzzy clustering to reclassify MYI in the transition zone.The HY-2B K-means+FC results were compared with the ice type products[including the Ocean and Sea Ice Satellite Application Facility(OSI SAF)sea ice type product and the Equal-Area Scalable Earth-Grid sea ice age dataset],and showed agreement in the time series of MYI extent.Intercomparisons in the transition zone indicated that the HY-2B K-means+FC results can identify more old ice than the OSI SAF product,but with an underestimation in identifying second-year ice.Comparisons between K-means and Kmeans+FC results were performed using regional ice charts and Sentinel-1 synthetic aperture radar(SAR)data.By adding fuzzy clustering,the MYI is more consistent with the ice charts,with the overall accuracy(OA)increasing by 0.9%–6.5%.Comparing against SAR images,it is suggested that more scattered MYI floes can be identified by fuzzy clustering,and the OA is increased by about 3%in middle freezing season and 7%–20%in early and late freezing season. 展开更多
关键词 sea ice classification Arctic multiyear ice Haiyang-2B transition zone microwave remote sensing fuzzy clustering
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Nanomechanical Characteristics of Interfacial Transition Zone in Nano-Engineered Concrete 认领 引用 被引量：13
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作者 Xinyue Wang Sufen Dong +2 位作者 Zhenming Li Baoguo Han Jinping Ou 《Engineering》 SCIE EI CAS CSCD 2022年第10期99-109,共11页
This study investigates the effects of nanofillers on the interfacial transition zone(ITZ)between aggregate and cement paste by using nanoindentation and statistical nanoindentation techniques.Moreover,the underlying ... This study investigates the effects of nanofillers on the interfacial transition zone(ITZ)between aggregate and cement paste by using nanoindentation and statistical nanoindentation techniques.Moreover,the underlying mechanisms are revealed through micromechanical modeling.The nanoindentation results indicate that incorporating nanofillers increases the degree of hydration in the ITZ,reduces the content of micropores and low-density calcium silicate hydrate(LD C-S-H),and increases the content of highdensity C-S-H(HD C-S-H)and ultra high-density C-S-H(UHD C-S-H).In particular,a new phase,namely nano-core-induced low-density C-S-H(NCILD C-S-H),with a superior hardness of 2.50 GPa and an indentation modulus similar to those of HD C-S-H or UHD C-S-H was identified in this study.The modeling results revealed that the presence of nanofillers increased the packing density of LD CS-H and significantly enhanced the interaction(adhesion and friction)among the basic building blocks of C-S-H gels owing to the formation of nano-core-shell elements,thereby facilitating the formation of NCILD C-S-H and further improving the performance of the ITZ.This study provides insight into the effects of nano fillers on the ITZ in concrete at the nanoscale. 展开更多
关键词 Concrete Nanofiller Interfacial transition zone Nanoindentation Micromechanical modeling Nano-core effect
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Forming Limit and Thickness Transition Zone Movement for Tailor Rolled Blank during Drawing Process 认领 引用 被引量：10
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作者 Hua-wei ZHANG Xiang-hua LIU +2 位作者 Li-zhong LIU Ping HU Jia-lu WU 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2016年第3期185-189,共5页
The process of automobile lightweight can be promoted by the application of tailor rolled blank（TRB）in the automobile industry.Therefore,research on the formability of TRB is of good practical significance and appli... The process of automobile lightweight can be promoted by the application of tailor rolled blank（TRB）in the automobile industry.Therefore,research on the formability of TRB is of good practical significance and application value because of the enormous potential of TRB in the aspect of automobile lightweight.Aiming at the present condition of lack of researches on the influence of characteristic parameters on TRB drawing process,the drawing formability of TRB was studied with a combination method of simulation and experiment by taking square box as the research object.Firstly,drawing simulation and experiment of TRB were carried out.Then,effects of thickness transition zone（TTZ）position and blank size on the drawing formability of TRB were analyzed.Forming limit and TTZ movement for TRB square box during the drawing process were respectively discussed,when transition zones of TRB were located at different positions and blanks were of different sizes.The results indicate that lubrication condition exerts greater influence on TRB forming limit in comparison with TTZ movement,and the smaller blank size and TTZ being located at the blank center or slightly offset to the thinner side are preferable for acquiring greater forming limit and smaller TTZ movement. 展开更多
关键词 tailor rolled blank square box forming limit thickness transition zone movement drawing formability
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Quantitative Analysis and Affecting Factors of the Overlapping Degree of Interfacial Transition Zone between Neighboring Aggregates in Concrete 认领 引用 被引量：7
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作者 SUN Guowen SUN Wei +1 位作者 ZHANG Yunsheng LIU Zhiyong 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第1期147-153,共7页
Based on the nearest surface function formula,a quantitative formula to measure the overlapping degree between the interfacial transition zone(ITZ)of neighboring aggregate particles was put forward.The formula was fur... Based on the nearest surface function formula,a quantitative formula to measure the overlapping degree between the interfacial transition zone(ITZ)of neighboring aggregate particles was put forward.The formula was further deduced to quantitatively analyze the influence of the volume fraction of aggregate,ITZ thickness and the maximum aggregate diameter on the overlapping degree between neighboring ITZ.The volume of ITZ was quantitatively calculated in actual concrete by comparing the nearest surface function formula with an approximate method,that is the surface area of the aggregates multiplied by the uniform thickness of the ITZ layers.The results showed that the influencing order of these three factors on the overlapping degree between neighboring ITZ in turn was the interface thickness,aggregate volume fraction and the maximum aggregate diameter;As long as the interface thickness 50μm and the aggregate volume fraction 50%,the calculated error between two methods mentioned above is about 10%. 展开更多
关键词 concrete interfacial transition zone degree of overlapping volume fraction 发Fuller distribution
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Effect of the Entrained Air Void on Strength and Interfacial Transition Zone of Air-Entrained Mortar 认领 引用 被引量：9
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作者 高辉 ZHANG Xiong ZHANG Yongjuan 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第5期1020-1028,共9页
In order to facilitate the development and application of air entraining agents (AEA) in the high performance concrete, entrained air void structure parameters (air void size range from 10 to 1 600 mu m) of 28 d sifte... In order to facilitate the development and application of air entraining agents (AEA) in the high performance concrete, entrained air void structure parameters (air void size range from 10 to 1 600 mu m) of 28 d sifted mortar were measured by image analysis method. The relationship between the air void size distribution and strength of mortar was studied by methods of grey connection analysis and multiple linear regression analysis. The multiple linear regression equation was established with a correlation coefficient of 0.966. The weight of the affection of hierarchical porosity on the compressive strength ratio was also obtained. In addition, the effect of air voids on the paste-aggregate interfacial transition zone (ITZ) was analyzed by microhardness. The results show that the correlation between different pore size range and the compressive strength is negative. The effect of air void size distribution on 28 days compressive strength is different: under the condition of similar total porosity, with the increase of the porosity of the air void size, ranging from 10 to 200 mu m, and the decrease of the porosity, ranging from 200 to 1 600 mu m, the average air void diameter and mean free spacing are decreased; as well as the width of ITZ. On the contrary, the microhardness of the ITZ is increased while the compressive strength loss is decreased. 展开更多
关键词 air void structure compressive strength interfacial transition zone grey connection linear regression
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Evapotranspiration of an oasis-desert transition zone in the middle stream of Heihe River, Northwest China 认领 引用 被引量：17
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作者 LiWen ZHAO WenZhi ZHAO 《Journal of Arid Land》 SCIE CSCD 2014年第5期529-539,共11页
As a main component in water balance, evapotranspiration is of great importance for water saving and irrigation-measure making, especially in arid or semiarid regions. Although studies of evapotranspiration have been ... As a main component in water balance, evapotranspiration is of great importance for water saving and irrigation-measure making, especially in arid or semiarid regions. Although studies of evapotranspiration have been conducted for a long time, studies concentrated on oasis-desert transition zone are very limited. On the basis of the meteorological data and other parameters（e.g. leaf area index（LAI）） of an oasis-desert transition zone in the middle stream of Heihe River from 2005 to 2011, this paper calculated both reference（ET0） and actual evapotranspiration（ETc） using FAO56 Penman-Monteith and Penman-Monteith models, respectively. In combination with pan evaporation（Ep） measured by E601 pan evaporator, four aspects were analyzed：（1） ET0 was firstly verified by Ep;（2） Characteristics of ET0 and ETc were compared, while the influencing factors were also analyzed;（3） Since meteorological data are often unavailable for estimating ET0 through FAO56 Penman-Monteith model in this region, pan evaporation coefficient（Kp） is very important when using observed Ep to predict ET0. Under this circumstance, an empirical formula of Kp was put forward for this region;（4） Crop coefficient（Kc）, an important index to reflect evapotranspiration, was also analyzed. Results show that mean annual values of ET0 and ETc were 840 and 221 mm, respectively. On the daily bases, ET0 and ETc were 2.3 and 0.6 mm/d, respectively. The annual tendency of ET0 and ETc was very similar, but their amplitude was obviously different. The differences among ET0 and ETc were mainly attributed to the different meteorological variables and leaf area index. The calculated Kc was about 0.25 and showed little variation during the growing season, indicating that available water（e.g. precipitation and irrigation） of about 221 mm/a was required to keep the water balance in this region. The results provide an comprehensive analysis of evapotranspiration for an oasis-desert transition zone in the middle stream of Heihe River, which was seldom reported before. 展开更多
关键词 evapotranspiration pan evaporation water requirement arid region oasis-desert transition zone
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Influence Mechanism of Curing Regimes on Interfacial Transition Zone of Lightweight Ultra-High Performance Concrete 认领 引用 被引量：2
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作者 李洋 张高展 +3 位作者 YANG Jun ZHANG Jian DING Qingjun ZHAO Mingyu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第3期591-603,共13页
This study aims to clarify the effects of curing regimes and lightweight aggregate(LWA)on the morphology, width and mechanical properties of the interfacial transition zone(ITZ) of ultra-high performance concrete(UHPC... This study aims to clarify the effects of curing regimes and lightweight aggregate(LWA)on the morphology, width and mechanical properties of the interfacial transition zone(ITZ) of ultra-high performance concrete(UHPC), and provide reference for the selection of lightweight ultra-high performance concrete(L-UHPC) curing regimes and the pre-wetting degree LWA. The results show that, under the three curing regimes(standard curing, steam curing and autoclaved curing), LWA is tightly bound to the matrix without obvious boundaries. ITZ width increases with the water absorption of LWA and decreases with increasing curing temperature. The ITZ microhardness is the highest when water absorption is 3%, and the microhardness value is more stable with the distance from LWA. Steam and autoclaved curing increase ITZ microhardness compared to standard curing. As LWA pre-wetting and curing temperatures increase, the degree of hydration at the ITZ increases, generating high-density CSH(HD CSH) and ultra-high-density CSH(UHD CSH), and reducing unhydrated particles in ITZ. ITZ micro-mechanical properties are optimized due to hydration products being denser. 展开更多
关键词 curing regime ultra-high performance concrete lightweight aggregate interfacial transition zone meso-mechanical properties micro-mechanical properties
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Sandstone-concrete interface transition zone (ITZ) damage and debonding micromechanisms under freeze-thaw 认领 引用 被引量：4
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作者 YanJun Shen Huan Zhang +3 位作者 JinYuan Zhang HongWei Yang Xu Wang Jia Pan 《Research in Cold and Arid Regions》 CSCD 2021年第2期133-149,共17页
The sufficient bond between concrete and rock is an important prerequisite to ensure the effect of shotcrete support. However, in cold regions engineering protection system, the bond condition of rock and concrete sur... The sufficient bond between concrete and rock is an important prerequisite to ensure the effect of shotcrete support. However, in cold regions engineering protection system, the bond condition of rock and concrete surface is easily affected by freeze-thaw cycles, resulting in interface damage, debonding and even supporting failure. Understanding the micromechanisms of the damage and debonding of the rock-concrete interface is essential for improving the interface protection.Therefore, the micromorphology, micromechanical properties, and microdebonding evolution of the sandstone-concrete interface transition zone(ITZ) under varying freeze-thaw cycles(0, 5, 10, 15, 20) were studied using scanning electron microscope, stereoscopic microscope, and nano-indentation. Furthermore, the distribution range and evolution process of ITZ affected by freeze-thaw cycles were defined. Major findings of this study are as follows:(1) The microdamage evolution law of the ITZ under increasing freeze-thaw cycles is clarified, and the relationship between the number of cracks in the ITZ and freeze-thaw cycles is established;(2) As the number of freeze-thaw cycles increases, the ITZ's micromechanical strength decreases, and its development width tends to increase;(3) The damage and debonding evolution mechanisms of sandstone-concrete ITZ under freeze-thaw cycles is revealed, and its micromechanical evolution model induced by freeze-thaw cycles is proposed. 展开更多
关键词 sandstone-concrete interface transition zone(ITZ) freeze-thaw cycles nano-indentation damage and debonding
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Geochemistry and Petrogenesis of Volcanic Rocks from the Continent-Ocean Transition Zone in Northern South China Sea and Their Tectonic Implications 认领 引用 被引量：2
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作者 XU Yue YANG Yaoming +6 位作者 YU Hongjun GAO Wei GAO Xiangxing LIU Baohua TIAN Xu YANG Jichao ZHANG Wenquan 《Journal of Ocean University of China》 SCIE CAS CSCD 2020年第5期1051-1061,共11页
Miocene–Pliocene(22–5 Myr) volcanism and associated seamounts are abundant in the continent-ocean transition(COT) zone in the margin of the north South China Sea(SCS). The petrogenesis of volcanic rocks from these s... Miocene–Pliocene(22–5 Myr) volcanism and associated seamounts are abundant in the continent-ocean transition(COT) zone in the margin of the north South China Sea(SCS). The petrogenesis of volcanic rocks from these seamounts and regional tectonic evolution of COT zone are poorly known. In this paper, we obtained whole-rock major and trace element compositions and Sr-Nd-Pb isotopic data for these volcanic rocks from the Puyuan and Beipo seamounts within COT zone, in northeastern SCS. Based on the geochemical analyses, the volcanic rocks are classified as alkaline ocean island basalts(OIB) and enriched mid-ocean ridge basalts(E-MORB). The OIBs from the Puyuan seamount are alkaline trachybasalts and tephrites that show enrichment of the light rare earth elements(LREE) relative to heavy rare earth elements(HREE) and more radiogenic Sr-Nd isotopic compositions, and have significant ‘Dupal isotopic anomaly'. In contrast, the E-MORBs from the Beipo seamount are tholeiitic basalts that have less enrichment in LREE and less radiogenic Sr-Nd isotopic compositions than the counterparts from the Puyuan seamount. Petrological and geochemical differences between the OIBs and MORBs from these two seamounts can be explained by different mantle sources and tectonic evolution stages of the COT zone. Syn-spreading OIB type basalts from the Puyuan seamount were derived from an isotopically ‘enriched', and garnet facies-dominated pyroxenitic mantle transferred by the Hainan mantle plume. In contrast, post-spreading E-MORB type basalts from the Beipo seamount are considered to be derived from the melting of isotopically ‘depleted' pyroxenite mantle triggered by lithosphere bending and subsequent post-rifting at the lower continental slope of the northern margin. 展开更多
关键词 volcanic rocks geochemistry tectonic evolution South China Sea continent-ocean transition zone
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Dynamic Identification and Evolution of Urban-suburban-rural Transition Zones Based on the Blender of Natural and Humanistic Factors: A Case Study of Chengdu, China 认领 引用 被引量：2
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作者 DENG Wei JIANG Zhenyuan +3 位作者 ZHANG Shaoyao REN Ping ZHANG Hao WANG Zhanyun 《Chinese Geographical Science》 SCIE CSCD 2024年第5期791-809,共19页
Urban-suburban-rural(U-S-R)zones exhibit distinctive transitional characteristics in interaction between human and nature.U-S-R transition zones(U-S-RTZ)are also highlighting the function diversity and landscape heter... Urban-suburban-rural(U-S-R)zones exhibit distinctive transitional characteristics in interaction between human and nature.U-S-R transition zones(U-S-RTZ)are also highlighting the function diversity and landscape heterogeneity across territorial spaces.As a super megacity in western China,Chengdu’s rapid urbanization has driven the evolution of U-S-R spaces,resulting in a sequential structure.To promote the high-quality spatial development of urban-rural region in a structured and efficient manner,it is essential to con-duct a scientific examination of the multidimensional interconnection within the U-S-RTZ framework.By proposing a novel identifica-tion method of U-S-RTZ and taking Chengdu,China as a case study,grounded in a blender of natural and humanistic factors,this study quantitatively delineated and explored the spatial evolutions of U-S-RTZ and stated the optimization orientation and sustainable devel-opment strategies of the production-living-ecological spaces along the U-S-R gradients.The results show that:1)it is suitable for the quantitative analysis of U-S-RTZ by established three-dimensional identification system in this study.2)In 1990-2020,the urban-sub-urban transition zones(U-STZ)in Chengdu have continuously undergone a substantial increase,and the scale of the suburban-rural transition zones(S-RTZ)has continued to expand slightly,while the space of rural-ecological transition zones(R-ETZ)has noticeably compressed.3)The landuse dynamics within U-S-RTZ has gradually increased in 1990-2020.The main direction of landuse transition was from farmland to construction land or woodlands,with the expansion of construction land being the most significant.4)R-ETZ primarily focus on ecological functions,and there is a trade-off relationship between the production-ecological function within the S-RTZ,and in the U-STZ,production-living composite functions are prioritized.This study emphasizes the importance of elastic planning and precise governance within the U-S-RTZ in a rapid urbanization region,particularly highlighting the role of suburbs as landscape corridors and service hubs in urban-rural integration.It elucidates to the practical implications for achieving high-quality development of integrated U-S-R territorial spaces. 展开更多
关键词 transition zone urban-suburban-rural zones spatial identification evolution mechanism Chengdu,China
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Anal transition zone in the surgical management of ulcerative colitis 认领 引用 被引量：6
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作者 Jennifer Holder-Murray Alessandro Fichera 《World Journal of Gastroenterology》 SCIE CAS 2009年第7期769-773,共5页
Preservation of the anal transition zone has long been a significant source of controversy in the surgical management of ulcerative colitis.The two techniques for restorative proctocolectomy and ileal pouch anal anast... Preservation of the anal transition zone has long been a significant source of controversy in the surgical management of ulcerative colitis.The two techniques for restorative proctocolectomy and ileal pouch anal anastomosis(RPC IPAA) in common practice are a stapled anastomosis and a handsewn anastomosis;these techniques differ in the amount of remaining rectal mucosa and therefore the presence of the anal transition zone following surgery.Each technique has advantages and disadvantages in long-term functional outcomes,operative and postoperative complications,and risk of neoplasia.Therefore,we propose a selective approach to performing a stapled RPC IPAA based on the presence of dysplasia in the preoperative endoscopic evaluation. 展开更多
关键词 Anal transition zone Ileal pouch analanastomosis Restorative proctocolectomy Ulcerativecolitis
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Imaging mantle transition zone discontinuities in southwest China from dense array ambient noise interferometry 认领 引用 被引量：3
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作者 Jikun Feng Huajian Yao Weitao Wang 《Earthquake Science》 CSCD 2018年第5期301-310,共10页
Body waves retrieved from ambient noise cross-correlation functions（NCFs） have been reported by more and more recent studies in addition to the dominant recovered surface waves. And one of important applications of ... Body waves retrieved from ambient noise cross-correlation functions（NCFs） have been reported by more and more recent studies in addition to the dominant recovered surface waves. And one of important applications of these recovered body waves is to investigate the structure of discontinuities within the mantle transition zone（MTZ）. In this study, clear body wave phases reflected from the MTZ discontinuities at 410 km and 660 km have been observed on the NCFs in the frequency band of 0.1–0.2 Hz from a dense regional seismic array in southwest China. The original timedomain reflected signals in the NCFs were first converted to the depth-domain NCFs based on a velocity model before they were further stacked spatially within different bins. Then the depth-domain NCFs were stacked to investigate the lateral variations of the MTZ discontinuities, that is, the 410-km and 660-km discontinuities. Our results exhibit a simple and lateral coherent P;P phase and a much more complicated P;P phase along two profiles, which are in good agreement with mineralogical prediction and recent receiver function studies in the same area. This interferometric method can provide stable reflected body wave phases mainly in the frequency band 0.1–0.2 Hz due to the secondary microseism noise, which can be potentially used for high-resolution mantle interface imaging. This approach is also a good complement to traditional imaging methods, such as receiver function imaging. 展开更多
关键词 ambient noise interferometry mantle transition zone 410-km and 660-km discontinuities reflected body waves southwest China
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North slope transition zone of Songnan-Baodao sag in Qiongdongnan Basin and its control on medium and large gas fields,South China Sea 认领 引用 被引量：6
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作者 XU Changgui YOU Li 《Petroleum Exploration and Development》 SCIE 2022年第6期1229-1242,共14页
Based on analysis of newly collected 3D seismic and drilled well data,the geological structure and fault system of Baodao sag have been systematically examined to figure out characteristics of the transition fault ter... Based on analysis of newly collected 3D seismic and drilled well data,the geological structure and fault system of Baodao sag have been systematically examined to figure out characteristics of the transition fault terrace belt and its control on the formation of natural gas reservoirs.The research results show that the Baodao sag has the northern fault terrace belt,central depression belt and southern slope belt developed,among them,the northern fault terrace belt consists of multiple transition fault terrace belts such as Baodao B,A and C from west to east which control the source rocks,traps,reservoirs,oil and gas migration and hydrocarbon enrichment in the Baodao sag.The activity of the main fault of the transition belt in the sedimentary period of Yacheng Formation in the Early Oligocene controlled the hydrocarbon generation kitchen and hydrocarbon generation potential.From west to east,getting closer to the provenance,the transition belt increased in activity strength,thickness of source rock and scale of delta,and had multiple hydrocarbon generation depressions developed.The main fault had local compression under the background of tension and torsion,giving rise to composite traps under the background of large nose structure,and the Baodao A and Baodao C traps to the east are larger than Baodao B trap.Multiple fault terraces controlled the material source input from the uplift area to form large delta sand bodies,and the synthetic transition belt of the west and middle sections and the gentle slope of the east section of the F12 fault in the Baodao A transition belt controlled the input of two major material sources,giving rise to a number of delta lobes in the west and east branches.The large structural ridge formed under the control of the main fault close to the hydrocarbon generation center allows efficient migration and accumulation of oil and gas.The combination mode and active time of the main faults matched well with the natural gas charging period,resulting in the hydrocarbon gas enrichment.Baodao A transition belt is adjacent to Baodao 27,25 and 21 lows,where large braided river delta deposits supplied by Shenhu uplift provenance develop,and it is characterized by large structural ridges allowing high efficient hydrocarbon accumulation,parallel combination of main faults and early cessation of faulting activity,so it is a favorable area for hydrocarbon gas accumulation.Thick high-quality gas reservoirs have been revealed through drilling,leading to the discovery of the first large-scale gas field in Baodo 21-1 of Baodao sag.This discovery also confirms that the north transition zone of Songnan-Baodao sag has good reservoir forming conditions,and the transition fault terrace belt has great exploration potential eastward. 展开更多
关键词 Qiongdongnan Basin Songnan-Baodao sag fault transition zone PaleogeneBaodo 21-1 medium and large gas fields large structural ridge composite trap hydrocarbon gas
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Unraveling the Stray Current-Induced Interfacial Transition Zone(ITZ)Effect on Sulfate Corrosion in Concrete 认领 引用 被引量：1
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作者 Yong-Qing Chen Lin-Ya Liu +3 位作者 Da-Wei Huang Qing-Song Feng Ren-Peng Chen Xin Kang 《Engineering》 SCIE EI CAS CSCD 2024年第10期130-152,共23页
The rail transit in sulfate-rich areas faces the combined effects of stray current and salt corrosion;however,the sulfate ion transport and concrete degradation mechanisms under such conditions are still unclear.To ad... The rail transit in sulfate-rich areas faces the combined effects of stray current and salt corrosion;however,the sulfate ion transport and concrete degradation mechanisms under such conditions are still unclear.To address this issue,novel sulfate transport and mesoscale splitting tests were designed,with a focus on considering the differences between the interfacial transition zone(ITZ)and cement matrix.Under the influence of stray current,the ITZ played a pivotal role in regulating the transport and mechanical failure processes of sulfate attack,while the tortuous and blocking effects of aggregates almost disappeared.This phenomenon was termed the“stray current-induced ITZ effect.”The experimental data revealed that the difference in sulfate ion transport attributed to the ITZ ranged from 1.90 to 2.31 times,while the difference in splitting strength ranged from 1.56 to 1.64 times.Through the real-time synchronization of splitting experiments and microsecond-responsive particle image velocimetry(PIV)technology,the mechanical properties were exposed to the consequences of the stray currentinduced ITZ effect.The number of splitting cracks in the concrete increased,rather than along the central axis,which was significantly different from the conditions without stray current and the ideal Brazilian disk test.Furthermore,a sulfate ion mass transfer model that incorporates reactivity and electrodiffusion was meticulously constructed.The embedded finite element calculation exhibited excellent agreement with the experimental results,indicating its reliability and accuracy.Additionally,the stress field was determined utilizing analytical methods,and the mechanism underlying crack propagation was successfully obtained.Compared to the cement matrix,a stray current led to more sulfates,more microstructure degradation,and greater increases in thickness and porosity in the ITZ,which was considered to be the essence of the stray current-induced ITZ effect. 展开更多
关键词 Interfacial transition zone(ITZ)effect Stray current Sulfate attack Transport mechanism Splitting test Microstructure
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Multi-parametric MR imaging of transition zone prostate cancer:Imaging features,detection and staging 认领 引用 被引量：3
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作者 Arda Kayhan Xiaobing Fan +1 位作者 Jacob Oommen Aytekin Oto 《World Journal of Radiology》 2010年第5期180-187,共8页
Magnetic resonance(MR)imaging has been increasingly used in the evaluation of prostate cancer.As studies have suggested that the majority of cancers arise from the peripheral zone(PZ),MR imaging has focused on the PZ ... Magnetic resonance(MR)imaging has been increasingly used in the evaluation of prostate cancer.As studies have suggested that the majority of cancers arise from the peripheral zone(PZ),MR imaging has focused on the PZ of the prostate gland thus far.However,a considerable number of cancers(up to 30%)originate in the transition zone(TZ),substantially contributing to morbidity and mortality.Therefore,research is needed on the TZ of the prostate gland.Recently,MR imaging and advanced MR techniques have been gaining acceptance in evaluation of the TZ.In this article,the MR imaging features of TZ prostate cancers,the role of MR imaging in TZ cancer detection and staging,and recent advanced MR techniques will be discussed in light of the literature. 展开更多
关键词 Multi-parametric magnetic resonance imaging Prostate cancer Transition zone
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