A Level考试素有“英国高考”之称。其制度演进大致经历了发轫与探索、扩张与调适、回归与重塑三个阶段,其主要变革内容包括四个方面:组织形式从年终末考的线性考试模式发展为一年多考的模块化考试,再回归线性考试模式;考试评价从常模...A Level考试素有“英国高考”之称。其制度演进大致经历了发轫与探索、扩张与调适、回归与重塑三个阶段,其主要变革内容包括四个方面:组织形式从年终末考的线性考试模式发展为一年多考的模块化考试,再回归线性考试模式;考试评价从常模参照转变为标准参照,评价手段逐步优化;考试要求从注重学科深度转变为强调知识广度,再发展为追求广度和深度并重;考试内容从偏重学术性转变为普职并重,再发展为职普融通和强调基础学科。变革的动因既有来自外部的国际竞争加剧和国内政党轮替,也有来自内部的文化价值观驱动和考试选才效度追求。A Level考试制度对我国高考改革有一定启发,我国可结合国情,以基础学科为支点、职普融通为路径、多样化的考试选择为依托、预测效度为导向,开展本土化探索。展开更多
To solve the problems of blindness and inefficiency existing in the determination of meso-level mechanical parameters of particle flow code (PFC) models, we firstly designed and numerically carried out orthogonal test...To solve the problems of blindness and inefficiency existing in the determination of meso-level mechanical parameters of particle flow code (PFC) models, we firstly designed and numerically carried out orthogonal tests on rock samples to investigate the correlations between macro-and meso-level mechanical parameters of rock-like bonded granular materials. Then based on the artificial intelligent technology, the intelligent prediction systems for nine meso-level mechanical parameters of PFC models were obtained by creating, training and testing the prediction models with the set of data got from the orthogonal tests. Lastly the prediction systems were used to predict the meso-level mechanical parameters of one kind of sandy mudstone, and according to the predicted results the macroscopic properties of the rock were obtained by numerical tests. The maximum relative error between the numerical test results and real rock properties is 3.28% which satisfies the precision requirement in engineering. It shows that this paper provides a fast and accurate method for the determination of meso-level mechanical parameters of PFC models.展开更多
Ligaments are densely connective soft tissues capable of maintaining stability and function of knee joint.As an important factor,the constitutive relation of ligament would affect its biomechanics and further play an ...Ligaments are densely connective soft tissues capable of maintaining stability and function of knee joint.As an important factor,the constitutive relation of ligament would affect its biomechanics and further play an essential role in the research on ligament injury,healing and treatment.The objective of this paper is to provide an overview of the current research on ligament constitutive relations on the macro,meso,and micro levels as well as the anatomy and histological structure of ligament.Some studies of biomechanical behaviors during ligament injury and healing periods have also been investigated.Based on the research on ligament constitutive relation in the past three decades,a discussion of some research perspectives is also presented,such as a validated accurate measuring method of in situ strain in ligament,a new constitutive relation involving the distribution of ultra-structural properties,and a rational estimation of ligament injury and healing process by the change of its ultra-structural or histological characteristics.展开更多
风场预报是智能网格预报的重要支撑,提高风场预报准确率,能够为风能预报提供核心保障。在综合评估2023年汛期CMA-MESO 3 km(China Meteorological Administration Mesoscale Model at 3 km resolution)模式在山西逐小时10 m风预报能力...风场预报是智能网格预报的重要支撑,提高风场预报准确率,能够为风能预报提供核心保障。在综合评估2023年汛期CMA-MESO 3 km(China Meteorological Administration Mesoscale Model at 3 km resolution)模式在山西逐小时10 m风预报能力的基础上,基于自适应Kalman滤波方法,开展针对纬向风(U)、经向风(V)的客观订正,以期建立适应山西复杂地形特征的客观预报方案,促进国产模式本地化业务应用。结果表明:①全风速预报偏大,预报误差呈“单峰型”日变化,峰值出现在18:00-20:00,正偏差主要位于忻定和太原盆地以及山西南部。②U、V预报误差与预报值呈显著正相关,需考虑不同强度预报风速误差随时效变化的特征,避免订正不足或过订正。③Kalman滤波方案(KM)订正幅度小且不稳定,订正后均方根误差R MSE削减不足6%,准确率提升不足2%。④基于动态分级的改进方案(CBKM)突破KM订正瓶颈,更准确地估计系统误差并有效订正,更好再现不同地区风速日变化,平均误差M E趋近0,R MSE削减32.8%,风向、风速预报准确率分别提升8.29%、7.92%,峰值时刻订正率达83.49%。展开更多
To explore water level variations and their dynamic influence on the water quality of Huayang Lakes,the water level from 1967 to 2023 and water quality from 2015 to 2023 were analyzed using the Mann–Kendall trend tes...To explore water level variations and their dynamic influence on the water quality of Huayang Lakes,the water level from 1967 to 2023 and water quality from 2015 to 2023 were analyzed using the Mann–Kendall trend test,box plots,and violin plots.The results show a notable hydrological rhythm of water level alternation between dry and flood seasons in Huayang Lakes,with an average water level of 12.82 m and a monthly range of 11.21–17.24m.Since 2017,the water level of Huayang Rivers has shown a decreasing trend of–0.02 m/a.Total phosphorus(TP)has become the primary pollutant.The TP concentrations in Longgan Lake(the largest lake)during the dry,rising,flood,and retreating seasons from 2015 to 2023were 0.083,0.061,0.050,and 0.059 mg/L,respectively.The effect of water level on TP was mainly observed during the low-water period.When the water level in the dry season rose to 12.25 and 13.00 m,the percentage of TP exceeding 0.1 mg/L in Longgan Lake decreased to 55.8%and 33.3%,respectively.During the dry season,wind and wave disturbances caused the release of endogenous phosphorus in Huayang Lakes.This led to drastic fluctuations in TP concentration,reducing the correlation between water level and TP.When external control is limited,the water level during the dry season should be maintained between 12.25 and 13.0 m.Additionally,it is necessary to accelerate the restoration of submerged macrophyte species(such as Hydrilla verticillata and Vallisneria natans)in the Huayang Rivers.展开更多
Accurate prediction of water level changes in reservoirs is crucial for optimizing the operation of reservoir projects and ensuring their safety.This study proposed a method for reservoir water level prediction based ...Accurate prediction of water level changes in reservoirs is crucial for optimizing the operation of reservoir projects and ensuring their safety.This study proposed a method for reservoir water level prediction based on CEEMDAN-FE and RUN-SVM-RBFNN algorithms.By integrating the adaptive complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN)method and fuzzy entropy(FE)with the new and highly efficient Runge–Kuta optimizer(RUN),adaptive parameter optimization for the support vector machine(SVM)and radial basis function neural network(RBFNN)algorithms was achieved.Regression prediction was conducted on the two reconstructed sequences using SVM and RBFNN according to their respective features.This approach improved the accuracy and stability of predictions.In terms of accuracy,the combined model outperformed single models,with the determination coefficient,root mean square error,and mean absolute error values of 0.9975,0.2418 m,and 0.1616 m,respectively.In terms of stability,the model predicted more consistently in training and testing periods,with stable overall prediction accuracy and a better adaptive ability to complex datasets.The case study demonstrated that the combined prediction model effectively addressed the environmental factors affecting reservoir water levels,leveraged the strength of each predictive method,compensated for their limitations,and clarified the impacts of environmental factors on reservoir water levels.展开更多
For the diagnostics and health management of lithium-ion batteries,numerous models have been developed to understand their degradation characteristics.These models typically fall into two categories:data-driven models...For the diagnostics and health management of lithium-ion batteries,numerous models have been developed to understand their degradation characteristics.These models typically fall into two categories:data-driven models and physical models,each offering unique advantages but also facing limitations.Physics-informed neural networks(PINNs)provide a robust framework to integrate data-driven models with physical principles,ensuring consistency with underlying physics while enabling generalization across diverse operational conditions.This study introduces a PINN-based approach to reconstruct open circuit voltage(OCV)curves and estimate key ageing parameters at both the cell and electrode levels.These parameters include available capacity,electrode capacities,and lithium inventory capacity.The proposed method integrates OCV reconstruction models as functional components into convolutional neural networks(CNNs)and is validated using a public dataset.The results reveal that the estimated ageing parameters closely align with those obtained through offline OCV tests,with errors in reconstructed OCV curves remaining within 15 mV.This demonstrates the ability of the method to deliver fast and accurate degradation diagnostics at the electrode level,advancing the potential for precise and efficient battery health management.展开更多
Fluvial systems play a crucial role in coastal and riverine ecosystems, making it essential to understand their responses to sea level changes for preserving biodiversity and managing natural resources. The evolution ...Fluvial systems play a crucial role in coastal and riverine ecosystems, making it essential to understand their responses to sea level changes for preserving biodiversity and managing natural resources. The evolution of the modern Indus River Delta offers a rare opportunity to study the interplay between sea level fluctuations, tectonism, sediment supply, and the corresponding fluvial responses. This study employs the ‘SedSim' stratigraphic forward model to simulate the delta's evolution from 200 kyr to the next5 kyr, drawing on data from field observations, Landsat imagery, digital elevation models, and previous studies. The model consists of 205 layers, each representing a 1-kyr time step, covering the last two glacial-interglacial cycles. Between 200 kyr and 130 kyr, during a lowstand period, sedimentation on the delta plain continued due to partial flow from the Indus River. During the last interglacial(130–60 kyr), rising sea levels led to peak sediment deposition, characteristic of a highstand phase. From 60 kyr to 18 kyr, sea levels dropped to their lowest during the Last Glacial Maximum(LGM), resulting in extensive erosion and minimal deposition on the delta plain. From 18 kyr to the present, rapidly rising sea levels, coupled with intensified monsoon activity, increased sedimentation rates and triggered avulsion and aggradation processes. The model accurately predicted depositional thickness across the delta plain, indicating a maximum of ca. 200 m at the shoreline platform, ca. 175 m in the northeastern delta, and ca. 100 m in the central delta. The study underscores the delta's vulnerability to future sea level rise, which–at a projected rate of 1 m/kyr–could significantly influence the densely populated, low-lying delta plain. These findings offer valuable insights into the geomorphic evolution of the Indus Delta and emphasize the socioeconomic implications of sea level change, underscoring the importance of proactive management and adaptation strategies.展开更多
In the Northern Himalayan region of Southern Xizang (Tibet),from the Lower Triassic to Upper Eocene 73 Sequences have been identified, with an average duration of 2.9 Ma;these can in turn be grouped into 24 super-Sequ...In the Northern Himalayan region of Southern Xizang (Tibet),from the Lower Triassic to Upper Eocene 73 Sequences have been identified, with an average duration of 2.9 Ma;these can in turn be grouped into 24 super-Sequences and 6 super-sequence sets. During Mesozoic and Paleogene, several large sea - level falls occurred in the Eastern Neo-Tethys. Among the recognized sea- level falls, the important ones include those at the ages of 255 Ma, 215 Ma,177 Ma, 138 Ma, 103 Ma and 68 Ma .Those at 239 Ma, 215 Ma, 157 Ma,80 Ma, 50Ma and 36 Ma are also significant. The third-order Sequences and sea-level cycles Probably reflect mainly global sea - level fluctuations, while the higher rank cycles seem more closely related to the basin evolution of the Neo-Tethys. Based on the study, six major periods have been suggested for ths tectonic evolution of the Eastern Neo-Tethys and the plates, i. e. the Pangea Period (Pre-Triassic), continental rifting Period (Triassic to Early Jurassic ), inter-continental sea Period (Middle Jurassic ), continental divergence period (late Middle Jurassic to Early Cretaceous ), continental convergence period (Late Cretaceous ) and the continental collision Period (Paleogene ). These major Periods can be further subdivided into eight stages according to the basin evolution. In each of the periods and Stages, Sequences and their boundaries show clear characters related to the tectonic background. The study indicater that the initial breakup of the Pangea along the Indus- Yarlung may have taken Place around 239 Ma. The Late Bathonian to Early Callovian seems to have been a critical time in the evolution of the Neo-Tethys, with the turning Point around 158 Ma. The blocks split from the northern margin of the Gondwana continual did not obviously drift away from the Indian Plate until Callovian .The oceanic crust subduction in the Neo- Tethys may have Started at 113Ma, while the contraction of the ocean probably began at 107- 103 Ma. The initial contact of the Indian Plate with the Eurasian plate may have taken Place around 80 Ma, with strong uplifting and thrushng in Late Paleocene.展开更多
Nanjing University,Nanjing,China was the venue for the International Workshop“Climate and Environmental Evolution in the Mesozoic Greenhouse World”and 3rd IGCP 609 Workshop“Cretaceous Sea-Level Change”which were j...Nanjing University,Nanjing,China was the venue for the International Workshop“Climate and Environmental Evolution in the Mesozoic Greenhouse World”and 3rd IGCP 609 Workshop“Cretaceous Sea-Level Change”which were jointly held during September 5–11,2015.展开更多
Computed tomography is an indispensable X-ray imaging modality used to diagnose numerous pathologies, but it can also involve the delivery of high ionizing radiation doses harmful to the health of patients. This study...Computed tomography is an indispensable X-ray imaging modality used to diagnose numerous pathologies, but it can also involve the delivery of high ionizing radiation doses harmful to the health of patients. This study aims to survey the level of radiation doses delivered to child patients during head exams in CT imaging to set up the Dosimetric Reference Levels (DRLs), a routine dose optimization tool, based on data acquired at the University Hospital of Angré (UHA), the University Hospital of Treichville (UHT) and the Polyclinic Hospital Farah (Farah) for optimizing procedures in Ivorian hospitals. Prospectively performed on 334 CT images of 186 child patients, this study was carried out on CT systems such as Hitachi Scenaria, Sinovision Insitum, and Philips Incisive used respectively at UHA, UHT and Farah. Children’s scan data were classified into four age bands: vol or dose-length product as DLP) value, whatever the hospital, increases with respect to the age of child patients. Based on the 75th percentile of the whole dose distributions, the DRLs of the CTDIvol is 54.37 mGy whatever the age groups and those of the DLP with respect to age bands are 1224.55 mGy∙cm, 1414.06 mGy∙cm, 1632.24 mGy.cm and 1544.57 mGy∙cm, respectively. The averaged values of CTDIvol and DLP smaller than the corresponding DRLs values suggest that practices in our three facilities are optimized. However, comparing our results with those from different international studies, we see that the CTDIvol and DLP values obtained in the present work are higher. These results suggest additional surveys to ensure our DRLs values and efforts from radiologists, imaging technicians and medical physicists to strengthen clinical procedures for the radiation protection of children undergoing CT scans in Côte d’Ivoire.展开更多
Metallogenic research on structural levels can reveal vertical patterns of mineralization and facilitate the deep exploration of economic minerals.However,research focusing on the correlation between structural levels...Metallogenic research on structural levels can reveal vertical patterns of mineralization and facilitate the deep exploration of economic minerals.However,research focusing on the correlation between structural levels and mineralization remains limited.In this study,we summarize the deformation patterns and associated mineral deposits observed at different crustal levels(i.e.,surface,shallow,middle,and deep structural levels,corresponding to depths of<2,2-8,8-15,and>15 km,respectively).Furthermore,we examine the genetic association between structural levels and metallogenesis,demonstrating that distinct structural levels are linked to specific types of mineralization.Key factors that vary across crustal levels include temperature,pressure,and fluid circulation.Ore-forming processes involve interactions between structures and fluids under varying temperatures and pressures.Structural levels influence mineralization by controlling the temperatures,pressures,and deformation mechanisms that drive the activation,migration,and enrichment of ore-forming materials.展开更多
基金the National Natural Science Foundation of China (Nos. 50674083 and 51074162) for its financial support
文摘To solve the problems of blindness and inefficiency existing in the determination of meso-level mechanical parameters of particle flow code (PFC) models, we firstly designed and numerically carried out orthogonal tests on rock samples to investigate the correlations between macro-and meso-level mechanical parameters of rock-like bonded granular materials. Then based on the artificial intelligent technology, the intelligent prediction systems for nine meso-level mechanical parameters of PFC models were obtained by creating, training and testing the prediction models with the set of data got from the orthogonal tests. Lastly the prediction systems were used to predict the meso-level mechanical parameters of one kind of sandy mudstone, and according to the predicted results the macroscopic properties of the rock were obtained by numerical tests. The maximum relative error between the numerical test results and real rock properties is 3.28% which satisfies the precision requirement in engineering. It shows that this paper provides a fast and accurate method for the determination of meso-level mechanical parameters of PFC models.
基金supported by the National Natural Science Foundation of China(No.51275267)
文摘Ligaments are densely connective soft tissues capable of maintaining stability and function of knee joint.As an important factor,the constitutive relation of ligament would affect its biomechanics and further play an essential role in the research on ligament injury,healing and treatment.The objective of this paper is to provide an overview of the current research on ligament constitutive relations on the macro,meso,and micro levels as well as the anatomy and histological structure of ligament.Some studies of biomechanical behaviors during ligament injury and healing periods have also been investigated.Based on the research on ligament constitutive relation in the past three decades,a discussion of some research perspectives is also presented,such as a validated accurate measuring method of in situ strain in ligament,a new constitutive relation involving the distribution of ultra-structural properties,and a rational estimation of ligament injury and healing process by the change of its ultra-structural or histological characteristics.
文摘风场预报是智能网格预报的重要支撑,提高风场预报准确率,能够为风能预报提供核心保障。在综合评估2023年汛期CMA-MESO 3 km(China Meteorological Administration Mesoscale Model at 3 km resolution)模式在山西逐小时10 m风预报能力的基础上,基于自适应Kalman滤波方法,开展针对纬向风(U)、经向风(V)的客观订正,以期建立适应山西复杂地形特征的客观预报方案,促进国产模式本地化业务应用。结果表明:①全风速预报偏大,预报误差呈“单峰型”日变化,峰值出现在18:00-20:00,正偏差主要位于忻定和太原盆地以及山西南部。②U、V预报误差与预报值呈显著正相关,需考虑不同强度预报风速误差随时效变化的特征,避免订正不足或过订正。③Kalman滤波方案(KM)订正幅度小且不稳定,订正后均方根误差R MSE削减不足6%,准确率提升不足2%。④基于动态分级的改进方案(CBKM)突破KM订正瓶颈,更准确地估计系统误差并有效订正,更好再现不同地区风速日变化,平均误差M E趋近0,R MSE削减32.8%,风向、风速预报准确率分别提升8.29%、7.92%,峰值时刻订正率达83.49%。
基金The Joint Research Project for Yangtze River Conservation,No.2022-LHYJ-02-0504-05-08Anhui Provincial Scientific Research Project for Universities,China No.2023AH050508。
文摘To explore water level variations and their dynamic influence on the water quality of Huayang Lakes,the water level from 1967 to 2023 and water quality from 2015 to 2023 were analyzed using the Mann–Kendall trend test,box plots,and violin plots.The results show a notable hydrological rhythm of water level alternation between dry and flood seasons in Huayang Lakes,with an average water level of 12.82 m and a monthly range of 11.21–17.24m.Since 2017,the water level of Huayang Rivers has shown a decreasing trend of–0.02 m/a.Total phosphorus(TP)has become the primary pollutant.The TP concentrations in Longgan Lake(the largest lake)during the dry,rising,flood,and retreating seasons from 2015 to 2023were 0.083,0.061,0.050,and 0.059 mg/L,respectively.The effect of water level on TP was mainly observed during the low-water period.When the water level in the dry season rose to 12.25 and 13.00 m,the percentage of TP exceeding 0.1 mg/L in Longgan Lake decreased to 55.8%and 33.3%,respectively.During the dry season,wind and wave disturbances caused the release of endogenous phosphorus in Huayang Lakes.This led to drastic fluctuations in TP concentration,reducing the correlation between water level and TP.When external control is limited,the water level during the dry season should be maintained between 12.25 and 13.0 m.Additionally,it is necessary to accelerate the restoration of submerged macrophyte species(such as Hydrilla verticillata and Vallisneria natans)in the Huayang Rivers.
基金supported by the National Key R&D Program of China(Grant No.2022YFC3005401)the National Natural Science Foundation of China(Grant No.52239009)。
文摘Accurate prediction of water level changes in reservoirs is crucial for optimizing the operation of reservoir projects and ensuring their safety.This study proposed a method for reservoir water level prediction based on CEEMDAN-FE and RUN-SVM-RBFNN algorithms.By integrating the adaptive complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN)method and fuzzy entropy(FE)with the new and highly efficient Runge–Kuta optimizer(RUN),adaptive parameter optimization for the support vector machine(SVM)and radial basis function neural network(RBFNN)algorithms was achieved.Regression prediction was conducted on the two reconstructed sequences using SVM and RBFNN according to their respective features.This approach improved the accuracy and stability of predictions.In terms of accuracy,the combined model outperformed single models,with the determination coefficient,root mean square error,and mean absolute error values of 0.9975,0.2418 m,and 0.1616 m,respectively.In terms of stability,the model predicted more consistently in training and testing periods,with stable overall prediction accuracy and a better adaptive ability to complex datasets.The case study demonstrated that the combined prediction model effectively addressed the environmental factors affecting reservoir water levels,leveraged the strength of each predictive method,compensated for their limitations,and clarified the impacts of environmental factors on reservoir water levels.
基金supported by the Beijing Natural Science Foundation(Grant No.L223013)。
文摘For the diagnostics and health management of lithium-ion batteries,numerous models have been developed to understand their degradation characteristics.These models typically fall into two categories:data-driven models and physical models,each offering unique advantages but also facing limitations.Physics-informed neural networks(PINNs)provide a robust framework to integrate data-driven models with physical principles,ensuring consistency with underlying physics while enabling generalization across diverse operational conditions.This study introduces a PINN-based approach to reconstruct open circuit voltage(OCV)curves and estimate key ageing parameters at both the cell and electrode levels.These parameters include available capacity,electrode capacities,and lithium inventory capacity.The proposed method integrates OCV reconstruction models as functional components into convolutional neural networks(CNNs)and is validated using a public dataset.The results reveal that the estimated ageing parameters closely align with those obtained through offline OCV tests,with errors in reconstructed OCV curves remaining within 15 mV.This demonstrates the ability of the method to deliver fast and accurate degradation diagnostics at the electrode level,advancing the potential for precise and efficient battery health management.
基金the Science and Technology Innovation Project of the Laoshan Laboratory (No. LSKJ202203402)the Major Research Project on the Tethys Geodynamic System from the National Science Foundation of China (No. 92055204)。
文摘Fluvial systems play a crucial role in coastal and riverine ecosystems, making it essential to understand their responses to sea level changes for preserving biodiversity and managing natural resources. The evolution of the modern Indus River Delta offers a rare opportunity to study the interplay between sea level fluctuations, tectonism, sediment supply, and the corresponding fluvial responses. This study employs the ‘SedSim' stratigraphic forward model to simulate the delta's evolution from 200 kyr to the next5 kyr, drawing on data from field observations, Landsat imagery, digital elevation models, and previous studies. The model consists of 205 layers, each representing a 1-kyr time step, covering the last two glacial-interglacial cycles. Between 200 kyr and 130 kyr, during a lowstand period, sedimentation on the delta plain continued due to partial flow from the Indus River. During the last interglacial(130–60 kyr), rising sea levels led to peak sediment deposition, characteristic of a highstand phase. From 60 kyr to 18 kyr, sea levels dropped to their lowest during the Last Glacial Maximum(LGM), resulting in extensive erosion and minimal deposition on the delta plain. From 18 kyr to the present, rapidly rising sea levels, coupled with intensified monsoon activity, increased sedimentation rates and triggered avulsion and aggradation processes. The model accurately predicted depositional thickness across the delta plain, indicating a maximum of ca. 200 m at the shoreline platform, ca. 175 m in the northeastern delta, and ca. 100 m in the central delta. The study underscores the delta's vulnerability to future sea level rise, which–at a projected rate of 1 m/kyr–could significantly influence the densely populated, low-lying delta plain. These findings offer valuable insights into the geomorphic evolution of the Indus Delta and emphasize the socioeconomic implications of sea level change, underscoring the importance of proactive management and adaptation strategies.
文摘In the Northern Himalayan region of Southern Xizang (Tibet),from the Lower Triassic to Upper Eocene 73 Sequences have been identified, with an average duration of 2.9 Ma;these can in turn be grouped into 24 super-Sequences and 6 super-sequence sets. During Mesozoic and Paleogene, several large sea - level falls occurred in the Eastern Neo-Tethys. Among the recognized sea- level falls, the important ones include those at the ages of 255 Ma, 215 Ma,177 Ma, 138 Ma, 103 Ma and 68 Ma .Those at 239 Ma, 215 Ma, 157 Ma,80 Ma, 50Ma and 36 Ma are also significant. The third-order Sequences and sea-level cycles Probably reflect mainly global sea - level fluctuations, while the higher rank cycles seem more closely related to the basin evolution of the Neo-Tethys. Based on the study, six major periods have been suggested for ths tectonic evolution of the Eastern Neo-Tethys and the plates, i. e. the Pangea Period (Pre-Triassic), continental rifting Period (Triassic to Early Jurassic ), inter-continental sea Period (Middle Jurassic ), continental divergence period (late Middle Jurassic to Early Cretaceous ), continental convergence period (Late Cretaceous ) and the continental collision Period (Paleogene ). These major Periods can be further subdivided into eight stages according to the basin evolution. In each of the periods and Stages, Sequences and their boundaries show clear characters related to the tectonic background. The study indicater that the initial breakup of the Pangea along the Indus- Yarlung may have taken Place around 239 Ma. The Late Bathonian to Early Callovian seems to have been a critical time in the evolution of the Neo-Tethys, with the turning Point around 158 Ma. The blocks split from the northern margin of the Gondwana continual did not obviously drift away from the Indian Plate until Callovian .The oceanic crust subduction in the Neo- Tethys may have Started at 113Ma, while the contraction of the ocean probably began at 107- 103 Ma. The initial contact of the Indian Plate with the Eurasian plate may have taken Place around 80 Ma, with strong uplifting and thrushng in Late Paleocene.
文摘Nanjing University,Nanjing,China was the venue for the International Workshop“Climate and Environmental Evolution in the Mesozoic Greenhouse World”and 3rd IGCP 609 Workshop“Cretaceous Sea-Level Change”which were jointly held during September 5–11,2015.
文摘Computed tomography is an indispensable X-ray imaging modality used to diagnose numerous pathologies, but it can also involve the delivery of high ionizing radiation doses harmful to the health of patients. This study aims to survey the level of radiation doses delivered to child patients during head exams in CT imaging to set up the Dosimetric Reference Levels (DRLs), a routine dose optimization tool, based on data acquired at the University Hospital of Angré (UHA), the University Hospital of Treichville (UHT) and the Polyclinic Hospital Farah (Farah) for optimizing procedures in Ivorian hospitals. Prospectively performed on 334 CT images of 186 child patients, this study was carried out on CT systems such as Hitachi Scenaria, Sinovision Insitum, and Philips Incisive used respectively at UHA, UHT and Farah. Children’s scan data were classified into four age bands: vol or dose-length product as DLP) value, whatever the hospital, increases with respect to the age of child patients. Based on the 75th percentile of the whole dose distributions, the DRLs of the CTDIvol is 54.37 mGy whatever the age groups and those of the DLP with respect to age bands are 1224.55 mGy∙cm, 1414.06 mGy∙cm, 1632.24 mGy.cm and 1544.57 mGy∙cm, respectively. The averaged values of CTDIvol and DLP smaller than the corresponding DRLs values suggest that practices in our three facilities are optimized. However, comparing our results with those from different international studies, we see that the CTDIvol and DLP values obtained in the present work are higher. These results suggest additional surveys to ensure our DRLs values and efforts from radiologists, imaging technicians and medical physicists to strengthen clinical procedures for the radiation protection of children undergoing CT scans in Côte d’Ivoire.
基金supported by National Key Research and Development Program of China(Grant Nos.2022YFF0800903 and 2024YFC2909905)the National Natural Science Foundation of China(NSFC)(Grant Nos.42261144669,42262026,and 42273073).
文摘Metallogenic research on structural levels can reveal vertical patterns of mineralization and facilitate the deep exploration of economic minerals.However,research focusing on the correlation between structural levels and mineralization remains limited.In this study,we summarize the deformation patterns and associated mineral deposits observed at different crustal levels(i.e.,surface,shallow,middle,and deep structural levels,corresponding to depths of<2,2-8,8-15,and>15 km,respectively).Furthermore,we examine the genetic association between structural levels and metallogenesis,demonstrating that distinct structural levels are linked to specific types of mineralization.Key factors that vary across crustal levels include temperature,pressure,and fluid circulation.Ore-forming processes involve interactions between structures and fluids under varying temperatures and pressures.Structural levels influence mineralization by controlling the temperatures,pressures,and deformation mechanisms that drive the activation,migration,and enrichment of ore-forming materials.
