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Origin of nucleation and growth of extension twins in grains unsuitably oriented for twinning during deformation of Mg-1%Al 被引量:1
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作者 Biaobiao Yang Javier LLorca 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第3期1186-1203,共18页
A large number of anomalous extension twins,with low or even negative twinning Schmid factors,were found to nucleate and grow in a strongly textured Mg-1Al alloy during tensile deformation along the extruded direction... A large number of anomalous extension twins,with low or even negative twinning Schmid factors,were found to nucleate and grow in a strongly textured Mg-1Al alloy during tensile deformation along the extruded direction.The deformation mechanisms responsible for this behaviour were investigated through in-situ electron back-scattered diffraction,grain reference orientation deviation,and slip trace-modified lattice rotation.It was found that anomalous extension twins nucleated mainly at the onset of plastic deformation at or near grain boundary triple junctions.They were associated with the severe strain incompatibility between neighbour grains as a result from the differentbasal slip-induced lattice rotations.Moreover,the anomalous twins were able to grow with the applied strain due to the continuous activation ofbasal slip in different neighbour grains,which enhanced the strain incompatibility.These results reveal the complexity of the deformation mechanisms in Mg alloys at the local level when deformed along hard orientations. 展开更多
关键词 Magnesium extension twinning In-situ electron back-scattered diffraction basal slip Deformation mechanisms.
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Diagnostic Study of an Extreme Explosive Cyclone over the Kuroshio/Kuroshio Extension Region 被引量:1
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作者 ZHANG Shuqin LIAO Qinghua +4 位作者 LIU Chunlei GAO Xiaoyu LONG Jingchao LI Pengyuan XU Jianjun 《Journal of Ocean University of China》 SCIE CAS CSCD 2024年第3期605-617,共13页
Explosive cyclones(ECs)occur frequently over the Kuroshio/Kuroshio Extension region.The most rapidly intensified EC over the Kuroshio/Kuroshio Extension region during the 42 years(1979-2020)of cold seasons(October-Apr... Explosive cyclones(ECs)occur frequently over the Kuroshio/Kuroshio Extension region.The most rapidly intensified EC over the Kuroshio/Kuroshio Extension region during the 42 years(1979-2020)of cold seasons(October-April)was studied to reveal the variations of the key factors at different explosive-developing stages.This EC had weak low-level baroclinicity,mid-level cyclonic-vorticity advection,and strong low-level water vapor convergence at the initial explosive-developing stage.The low-level baroclinicity and mid-level cyclonic-vorticity advection increased substantially during the maximum-deepening-rate stage.The diagnostic analyses using the Zwack-Okossi equation showed that diabatic heating was the main contributor to the initial rapid intensification of this EC.The cyclonic-vorticity advection and warm-air advection enhanced rapidly in the middle and upper troposphere and contributed to the maximum rapid intensification,whereas the diabatic heating weakened slightly in the mid-low troposphere.The relative contribution of the diabatic heating decreased from the initial explosive-developing stage to the maximum-deepening-rate stage due to the enhancement of other factors(the cyclonic-vorticity advection and warm-air advection).Furthermore,the physical factors contributing to this EC varied with the explosive-developing stage.The non-key factors at the initial explosive-developing stage need attention to forecast the rapid intensification. 展开更多
关键词 explosive cyclone diabatic heating cyclonic-vorticity advection rapid intensification the Kuroshio/Kuroshio extension region
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Estimation of Displacement and Extension due to Reverse Drag of Normal Faults: Forward Method
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作者 Shunshan Xu Angel Francisco Nieto-Samaniego +1 位作者 Huilong Xu Susana Alicia Alaniz-Álvarez 《International Journal of Geosciences》 CAS 2024年第1期25-39,共15页
In the case of reverse drag of normal faulting, the displacement and horizontal extension are determined based on the established equations for the three mechanisms: rigid body, vertical shear and inclined shear. Ther... In the case of reverse drag of normal faulting, the displacement and horizontal extension are determined based on the established equations for the three mechanisms: rigid body, vertical shear and inclined shear. There are three sub-cases of basal detachment for the rigid body model: horizontal detachment, antithetic detachment and synthetic detachment. For the rigid body model, the established equations indicate that the total displacement on the synthetic base (D<sub>t2</sub>) is the largest, that on the horizontal base (D<sub>t1</sub>) is moderate, and that on the antithetic base (D<sub>t3</sub>) is the smallest. On the other hand, the value of (D<sub>t1</sub>) is larger than the displacement for the vertical shear (D<sub>t4</sub>). The value of (D<sub>t1</sub>) is larger than or less than the displacement for the inclined shear (D<sub>t5</sub>) depending on the original fault dip δ<sub>0</sub>, bedding angle θ, and the angle of shear direction β. For all original parameters, the value of D<sub>t5</sub> is less than the value of D<sub>t4</sub>. Also, by comparing three rotation mechanisms, we find that the inclined shear produces largest extension, the rigid body model with horizontal detachment produces the smallest extension, and the vertical shear model produces moderate extension. 展开更多
关键词 Fault Rotation Fault Drag Fault Displacement extension Forward Model
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Analysis of the Digital Skill Gap of Agricultural Extension Personnel in South-East, Nigeria
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作者 Ogbonnaya Okoro Aja Chigozie Cyril Asiabaka +1 位作者 Anthony Okorie Ani Edna Chioma Matthews-Njoku 《Agricultural Sciences》 2024年第9期1057-1070,共14页
The study analysed the digital skill gap of agricultural extension personnel on the use of digital technologies for extension services delivery in South-East, Nigeria. The specific objectives were to describe the soci... The study analysed the digital skill gap of agricultural extension personnel on the use of digital technologies for extension services delivery in South-East, Nigeria. The specific objectives were to describe the socioeconomic characteristics of agricultural extension personnel in South-East Nigeria and identify the digital skill gaps among agricultural extension personnel in the area of study. Purposive sampling technique was used to select 364 Agricultural Extension personnel for the study. Data were collected through the use of structured questionnaire and were analysed using simple descriptive statistical tools such as percentages, mean score, and standard deviation. Findings indicated that most of the personnel were male (57.8%), within the age bracket of 38 - 47 years (62.9%), had B.Sc./HND as their highest educational qualification (74.7%), married (86.3%), and had a household size of 6 - 10 Persons (57.7%). It was further revealed that the majority (70.1%) were members of professional organization, earned a monthly income of N50,001.00 - N100,000.00 (65.7%), had a work experience of 11 - 15 years (51.1%), and owned a smartphone/ iPad/laptop (91.5%). Findings further indicated that they had moderate skill gap in Basic Computer skills (Mean = 4.32), and digital communication and collaboration skills (Mean = 4.26). Findings also showed that they had a high skill gap in digital technical skills (Mean = 2.46), digital data analysis skills (Mean = 2.09), digital content creation skills (Mean = 2.43), digital ethical skills (Mean = 2.79), multimedia production skills (Mean = 2.81), and video library management skills (Mean = 2.39). The study concluded that though there exists a high digital skill gap among agricultural extension personnel in South-East, Nigeria, their socioeconomic characteristics are capable of supporting the implementation of digital extension services in the area. The study recommended that the management of Agricultural Development Programs in South-East, Nigeria, should provide digital training for extension personnel to close the digital skill gap that currently exists among the personnel. 展开更多
关键词 Agricultural extension Personnel Socioeconomic Characteristics Digital Skill Gap South-East NIGERIA
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Comparative Study of the Socioeconomic Characteristics and Digital Literacy Level of Agricultural Extension Personnel in Imo and Ebonyi States, South-East, Nigeria
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作者 Ogbonnaya Okoro Aja Cyril Chigozie Asiabaka +1 位作者 Anthony Okorie Ani Edna Chioma Matthews-Njoku 《Agricultural Sciences》 2024年第2期230-245,共16页
The study comparatively analysed the socioeconomic characteristics and digital literacy level of Agricultural Extension personnel (AEP) in Ebonyi and Imo States, South-East, Nigeria. The specific objectives were to de... The study comparatively analysed the socioeconomic characteristics and digital literacy level of Agricultural Extension personnel (AEP) in Ebonyi and Imo States, South-East, Nigeria. The specific objectives were to describe the socioeconomic characteristics of agricultural extension personnel in Ebonyi and Imo States, and to ascertain the digital literacy level of AEP in the studied states. Purposive sampling technique was used to select 312 Agricultural Extension personnel (132 from Ebonyi State Agricultural Development Program and 180 from Imo State Agricultural Development Program) for the study. Data were collected through the use of validated and structured questionnaire, and administered through the help of well-trained enumerators. Data were analysed using simple descriptive statistical tools such as percentages mean score, standard deviation and weighted mean. Findings indicated that they were more male in the both States (55.3% and 57.8%) for Ebonyi and Imo State respectively and that the average age of AEP in Ebonyi and Imo States were 44.7 years and 49.2 years respectively. It was further revealed that the majority (77.3% and 82.8%) had B.Sc./HND as their highest academic qualifications, belonged to professional organisations (62.1% and 75%), and were earning an average monthly income of N58,798 and N62,648 for Ebonyi and Imo State respectively. Also, it was revealed that their mean years of service were 12.4 years and 13.4 years for Ebonyi and Imo State respectively. Almost all of them (87.9% and 95.0%) own a smartphone, had access to the internet (80.3% and 90.0%), but do not own a laptop/ipad (82.6% and 72.8%) for Ebon-yi and Imo State respectively. Results further revealed that Agricultural extension personnel in both Ebonyi and Imo State respectively had low digital literacy level ( = 2.41 and 2.32). The study concluded that AEP in Ebonyi and Imo State respectively had similar socioeconomic characteristics and low level of digital literacy. The study recommended that the management of ADPs in both Ebonyi and Imo State should ensure the training of AEP in digital skills to enhance their digital literacy level to enable them use digital technologies in their work. 展开更多
关键词 Agricultural extension Personnel Digital Literacy Ebonyi State Imo State Socioeconomic Characteristics
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Wellbore Cleaning Degree and Hydraulic Extension in Shale Oil Horizontal Wells
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作者 Xin Ai Mian Chen 《Fluid Dynamics & Materials Processing》 EI 2024年第3期661-670,共10页
The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investiga... The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investigated experimentallyby focusing on the dimensionless cuttings bed height. A method is proposed to calculate the horizontalwellhydraulic extension taking into account the influence of the wellbore cleaning degree on the wellborepressure distribution and assess the effect of a variety of factors such as the bottom hole pressure, the circulatingpressure drop, the drilling pump performance and the formation properties. The analysis shows that the hydraulicextension of horizontal wells decreases with an increase in the cuttings bed height, and the higher the displacementof drilling fluid, the faster the hydraulic extension declines. The annular pressure drop of the horizontalsection increases with the increase of the cuttings bed height, resulting in a higher bottom-hole pressure. Severalarguments are provided to guide the safe drilling of shale oil horizontal wells and overcome the limits of currenttechnological approaches. 展开更多
关键词 Shale oil horizontal well hydraulic extension wellbore cleaning degree pressure distribution mechanism analysis
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Robust high frequency seismic bandwidth extension with a deep neural network trained using synthetic data
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作者 Paul Zwartjes Jewoo Yoo 《Artificial Intelligence in Geosciences》 2024年第1期64-81,共18页
Geophysicists interpreting seismic reflection data aim for the highest resolution possible as this facilitates the interpretation and discrimination of subtle geological features.Various deterministic methods based on... Geophysicists interpreting seismic reflection data aim for the highest resolution possible as this facilitates the interpretation and discrimination of subtle geological features.Various deterministic methods based on Wiener filtering exist to increase the temporal frequency bandwidth and compress the seismic wavelet in a process called spectral shaping.Auto-encoder neural networks with convolutional layers have been applied to this problem,with encouraging results,but the problem of generalization to unseen data remains.Most published works have used supervised learning with training data constructed from field seismic data or synthetic seismic data generated based on measured well logs or based on seismic wavefield modelling.This leads to satisfactory results on datasets similar to the training data but requires re-training of the networks for unseen data with different characteristics.In this work seek to improve the generalization,not by experimenting with network architecture(we use a conventional U-net with some small modifications),but by adopting a different approach to creating the training data for the supervised learning process.Although the network is important,at this stage of development we see more improvement in prediction results by altering the design of the training data than by architectural changes.The approach we take is to create synthetic training data consisting of simple geometric shapes convolved with a seismic wavelet.We created a very diverse training dataset consisting of 9000 seismic images with between 5 and 300 seismic events resembling seismic reflections that have geophysically motived perturbations in terms of shape and character.The 2D U-net we have trained can boost robustly and recursively the dominant frequency by 50%.We demonstrate this on unseen field data with different bandwidths and signal-to-noise ratios.Additionally,this 2D U-net can handle non-stationary wavelets and overlapping events of different bandwidth without creating excessive ringing.It is also robust in the presence of noise.The significance of this result is that it simplifies the effort of bandwidth extension and demonstrates the usefulness of auto-encoder neural network for geophysical data processing. 展开更多
关键词 RESOLUTION Seismic data u-Net Bandwidth extension Synthetic data
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The Effects of Infrastructure Projects on House Prices and Rents:Evidence from the HS2 Extension Cancellation in the UK
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作者 Wentao Zhu 《Journal of Sustainable Business and Economics》 2024年第2期76-94,共19页
This paper uses the HS2 extension cancellation in November 2021 as a quasi-experiment to study its impact on house prices and rents in Leeds.Using a DiD approach on repeat sales and monthly rents,I compare property va... This paper uses the HS2 extension cancellation in November 2021 as a quasi-experiment to study its impact on house prices and rents in Leeds.Using a DiD approach on repeat sales and monthly rents,I compare property values near the HS2 station and proposed construction site before and after the announcement.Results show a 3.6%decrease in house prices and a 3.9%decline in rents near the station,while properties near the construction site experienced a 2.4%increase in prices and a 2.1%rise in rents.This is the first paper to analyse the HS2 cancellation effect using panel data methods. 展开更多
关键词 HS2 extension cancellation Externalities House price effects Transport infrastructure Difference-in-Differences Model
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Landforms Evolution of Wadi Qudaid Area, West Central Arabian Shield, Saudi Arabia: An Example of the Role of the Geological Factors in the Urban Extensions
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作者 Ali A. Mesaed Mohammed A. M. Alghamdi Abdullah R. Sonbul 《Open Journal of Geology》 2020年第6期612-640,共29页
Wadi Qudaid is located in the west central part of Saudi Arabia. It about 135</span><span style="font-size:10pt;font-family:""> </span><span style="font-size:10pt;font-family:&... Wadi Qudaid is located in the west central part of Saudi Arabia. It about 135</span><span style="font-size:10pt;font-family:""> </span><span style="font-size:10pt;font-family:""><span style="font-family:Verdana;font-size:12px;">km to the northeast of Jeddah city along Al Haramein highway and it represents the upstream of the very large alluvial plain along the Red Sea coast. It runs in NE direction parallel to many wadis of the west central part of Saudi Arabia </span><i><span style="font-family:Verdana;font-size:12px;">i.e.</span></i><span style="font-family:Verdana;font-size:12px;"> Wadi Fatima, wadi Sitarah. The wadi floor is filled by Quaternary deposits which represent good groundwater aquifer. Geologically, the present-day residual landforms of Wadi Qudaid are composed mainly of Precambrian Arabia shield rocks overlained by Tertiary sedimentary rocks and finally harrat (Tertiary volcanic). The Precambrian rocks are represented by 1) a lower layered basic and intermediate volcanic and the intercalated volcaniclastics. This unit is correlatable with Samran Group, 2) an upper layered acidic volcanic and the intercalated acidic volcaniclastics. The Arabian shield rocks are intensively folded and dragged along the major NE faults. They are directly overlain by Tertiary basic volcanic (harrat) and the related volcanoclastic red beds). The main geomorphologic elements of the </span><span style="font-family:Verdana;font-size:12px;">study area include plateau, scarps, and the wadi floor. The plateau is represented </span><span style="font-family:Verdana;font-size:12px;">by the black basaltic sheet that contains some semi-rounded depressions filled with Quaternary eolian sands. The scarps of the main wadi and its tributaries are nearly steep and contain many asphaltic roads with some isolated cone hills detached from the scarps. Geomorphological, Wadi Qudaid</span><span style="font-family:Verdana;font-size:12px;"> represents the incomplete erosion cycle that begins with the formation of deep galleries and very steep and narrow wadies formed along the major NE faults and related fractures and folds. The progress of the erosion processes led to the formation of narrow interfluves as a result of pedimentation and sculpturing of the wadies sides by scarp retreat. The peniplanation stages of the erosion cycles are reached in the southwestern and the central part of the wadi where fast peniplained areas were formed. The results of this study revealed the role of the different geological processes (lithology, structural elements and climatic conditions) in the distribution of present-day human populations in urban extensions. Qudaid, Dhubaya-Jumah, Dabyah, Al Khamrah, Almansa and Al</span></span><span style="font-size:10pt;font-family:""> </span><span style="font-family:Verdana;">Massamah are the main villages of Wadi Qudaid area. 展开更多
关键词 Wadi Qudaid Geomorphology of Saudi Arabia Landforms Evolution Erosion Cycle Urban extensions
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SWAT和WetSpa Extension在罗玉沟流域的应用比较 被引量:2
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作者 韩旖旎 牛健植 张由松 《水资源与水工程学报》 2014年第3期133-137,共5页
近年来,运用水文模型来研究流域水文状况越来越普遍,本文以黄土高原丘陵沟壑区第三副区的典型小流域为例,基于SWAT和WetSpa Extension两个模型,从模型的输入数据、模型的参数和模型模拟结果等方面进行比较,以期为该区水沙模拟选择合适... 近年来,运用水文模型来研究流域水文状况越来越普遍,本文以黄土高原丘陵沟壑区第三副区的典型小流域为例,基于SWAT和WetSpa Extension两个模型,从模型的输入数据、模型的参数和模型模拟结果等方面进行比较,以期为该区水沙模拟选择合适水文模型并为将来模型性能的改进提供参考。连续15年的校准验证表明:两个模型都能得到较好的结果,而SWAT模型能应用于水文及泥沙等模拟过程,相对来说功能更全面;WetSpa Extension模型目前仅能提供水文模拟的模块,优点在于模拟时间步长较任意,可进行洪水模拟。 展开更多
关键词 SWAT模型 WetSpa extension模型 分布式模型 罗玉沟流域 水文模拟
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Research on the extension of Tamarix shrubs resulted from devel-opment projects in arid area 被引量:2
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作者 黄培祐 高瑞如 《Journal of Forestry Research》 SCIE CAS CSCD 2004年第1期45-48,J002,共5页
Tamarix plant is widely distributed in the arid areas of China for its great tolerance of draught, salt and alkali and attracts more attention by its strong capacity in windbreak and sand-fixations. “Tamarix dunes” ... Tamarix plant is widely distributed in the arid areas of China for its great tolerance of draught, salt and alkali and attracts more attention by its strong capacity in windbreak and sand-fixations. “Tamarix dunes” constitute special desert bio-landscape in arid area. During last several decades,Tamarix shrubs declined and “Tamarix dunes” were also severely destroyed due to the land exploitation and serious deforestation, etc. From the 1980s until now, the extending phenomenon ofTamarix shrubs caused by developmental projects such as building highway, railway was studied in the western dry area of China, including western section of Hexi Corridor of Gansu, railroads and highways around the two greatest basin in Xinjiang and interior regions in Gurbantonggut desert, through on-the-spot survey along the transportation lines and setting up sampling plots along the roads. It was found that large quantities ofTamarix plants grow in the catchment area of low-lying lands that were formed by bulldozer operation during road building period. The extension ofTamarix shrubs caused by engineering was similar to that of the other section of the area to some extent, but went beyond the original distribution. This extension is beneficial to the ecological restoration and re-vegetation of western region of China and plays an important role in control of the sandstorms and improvement of ecological environments. As a result, it is necessary to make a further study on the extending phenomenon ofTamarix shrubs and to seek approach to promote wider extension ofTamarix shrubs in suitable habitats. Key words Arid area - Tamarix - Development engineering - Vegetation extension CLC number S718.541 Document code A Article ID 1007-662X(2004)01-0045-04 Foundation Item: This study is supported by key projects of National Natural Science Foundation (39730100), National Foundation (30070640) and part of Project 973(G19990435).Biography: Huang Pei-You (1936-), Male, Professor in College of Life Science and Technology, Xinjiang University, Urumqi, 830046Responsible editor: Chai Ruihai 展开更多
关键词 Arid area TAMARIX Development engineering Vegetation extension
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Site-directed Mutagenesis Based on Overlap Extension PCR 被引量:4
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作者 雒丽娜 王盛 王玉炯 《Agricultural Science & Technology》 CAS 2012年第4期719-722,共4页
[Objective] To establish an efficient, convenient and economical method for site-directed mutagenesis. [Method] The target mutation was introduced into primers designed by DNAMAN5.0 software. Through overlap extension... [Objective] To establish an efficient, convenient and economical method for site-directed mutagenesis. [Method] The target mutation was introduced into primers designed by DNAMAN5.0 software. Through overlap extension PCR for twice obtained the mutation gene which of the full length of the recombinant Human Tissue type plasminogen activator (Reteplase). The mutation gene cloned it into pEASY- blunt simple cloning vector for sequencing. [Result] The sequencing results showed that three site mutations were fully consistent with the expected results (10~ site had been added a base-pair of A, C had been changed into G at 137~ site, G had been changed into A at 686~ site).Three site mutations were introduced by using overlap extension PCR on one-step. The overall rate of obtaining the mutant sites was 100%. Site-directed mutagenesis will clone the recombinant Human Tissue type plas- minogen activator and laid the basis for the functional study. [Conclusion] Site-directed mutagenesis was successfully implemented based on the overlap extension PCR which is an efficient, convenient and economical DNA-directed mutagenesis method. 展开更多
关键词 Overlap extension PCR Site-directed mutagenesis Human Tissue Plas- minogen Activator (Reteplase)
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Extension Study on the Use of Slope Farmland in West Region 被引量:7
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作者 杨赟 《Agricultural Science & Technology》 CAS 2010年第1期171-172,共2页
Based on the research of slope farmland in northern Shaanxi,the extension decision model was set up by the original theory of extenics. The optimal solution is obtained by expanding analysis,provide scientific basis f... Based on the research of slope farmland in northern Shaanxi,the extension decision model was set up by the original theory of extenics. The optimal solution is obtained by expanding analysis,provide scientific basis for decision-making and increase the economic benefits to farmers. 展开更多
关键词 Slope farmland Specialty Products extension decision
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岩石圈伸展的壳/幔拆离模型(Parallel Extension Tectonics):华北克拉通东部早白垩世岩石圈减薄与破坏机理 被引量:7
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作者 刘俊来 倪金龙 +4 位作者 陈小宇 Craddock JP 郑媛媛 孙彦琪 季雷 《岩石学报》 SCIE EI CAS CSCD 北大核心 2020年第8期2331-2343,共13页
华北克拉通岩石圈减薄和破坏机理长期以来存在争议,基于岩石学、岩石地球的化学分析研究突出强调深部过程的重要性。前人提出了两种重要模式:包括以拆沉作用为代表的top-down tectonics模型和以热-机械侵蚀与化学侵蚀,或地幔置换、交代... 华北克拉通岩石圈减薄和破坏机理长期以来存在争议,基于岩石学、岩石地球的化学分析研究突出强调深部过程的重要性。前人提出了两种重要模式:包括以拆沉作用为代表的top-down tectonics模型和以热-机械侵蚀与化学侵蚀,或地幔置换、交代作用的bottom-up tectonics模型。然而,对于这两种模式而言尚存在许多无法合理解释的问题,比如在此深部过程中,区域性岩石圈伸展有多大的贡献?地壳伸展构造是作为深部过程的响应,还是同为岩石圈伸展的产物?本文基于早白垩世东亚地区(尤其是华北克拉通东部地区)伸展构造与岩浆活动的综合分析,揭示出华北克拉通东部不同地区伸展构造变形与岩浆活动之间的时、空和成因关系有一定的差异。但整体上看,岩石圈伸展起着主导作用,控制着岩浆上侵和就位,在拆离断层下盘侵入形成各种规模的花岗质为主的侵入体,或于上盘喷发形成火山-沉积岩盆地。在伸展构造发育的不同阶段,可以有伸展早期、伸展期及伸展期后的岩浆活动。岩浆活动的强度及岩浆源区特点有显著的时空变化。一方面,在同一地区不同演化阶段其源区有很大的差异。表现为主体上是早期以古老下地壳源为主,随着壳/幔伸展作用演化,逐渐向混合源或独立幔源的演化。同时,不同地区岩浆源区的变化规律也显著不同。以胶辽地区为例,胶东整体上是壳幔混合源区对于岩浆演化有重要贡献;而辽东地区具有显著的源区演化特点:从剪切早期古老下地壳源区为主,并伴有幔源物质加入,剪切期古老下地壳为主,到剪切晚期和剪切期后以新生下地壳为主。本文认为岩石圈伸展的壳/幔拆离模型(Parallel Extension Tectonics),可以合理地解释华北克拉通及邻区早白垩世构造-岩浆活动性。在该模型中,遭受伸展的华北克拉通岩石圈发生壳-幔拆离作用。在岩石圈伸展作用期间,地壳层次的拆离作用与岩石圈地幔层次上的拆离作用可以是耦合的或者是解耦的,从而导致华北克拉通岩石圈减薄过程中在地壳尺度上的拆离作用与变质核杂岩的剥露有三种不同的类型:同岩浆活动型伸展(C型:Co-magmatism mode extension)、无岩浆活动型伸展(A型:Amagmatism mode extension)和多阶段混合型(M型:Multi-mode extension)。 展开更多
关键词 岩石圈不均匀伸展 壳幔拆离 同伸展岩浆作用 岩石圈伸展的壳幔拆离模型 华北克拉通
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Extension集合辨析 被引量:2
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作者 左静 《郑州工业大学学报》 2001年第2期20-22,共3页
xtension集合是可拓学理论的基础概念之一 .探讨Extension集合的特色和它与其它集合的关系 ,对于明晰可拓学的生存基础、研究价值和发展前景非常重要 .通过比较 3种集合对论域元素的识别与分类原则 ,指出Fuzzy集合Extension集合均以Can... xtension集合是可拓学理论的基础概念之一 .探讨Extension集合的特色和它与其它集合的关系 ,对于明晰可拓学的生存基础、研究价值和发展前景非常重要 .通过比较 3种集合对论域元素的识别与分类原则 ,指出Fuzzy集合Extension集合均以Cantor集合为基础 ,但各自又具有其它集合不可替代的独特之处 .Extension集合的特色在于它对论域元素潜在属性的识别角度和元素属性在特定变换下的可转换性的识别功能 . 展开更多
关键词 extension集合 CANTOR集合 FUZZY集合 可拓学 论域元素 关联函数
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Primer Extension-DHPLC检测线粒体DNA 12SrRNA常见耳聋相关突变方法的建立~△ 被引量:3
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作者 李琦 刘亚青 +3 位作者 孙晨 黄正华 田涛 戴朴 《听力学及言语疾病杂志》 CAS CSCD 北大核心 2019年第2期201-205,共5页
目的建立针对线粒体DNA 12SrRNA基因常见耳聋相关突变的Primer Extension-DHPLC(PE-DHPLC)基因诊断新方法。方法将包含线粒体DNA 12SrRNA 961insC、T1095C、C1494T、A1555G 4种不同突变的4例外周血DNA样本和4例正常对照标本经测序验证,... 目的建立针对线粒体DNA 12SrRNA基因常见耳聋相关突变的Primer Extension-DHPLC(PE-DHPLC)基因诊断新方法。方法将包含线粒体DNA 12SrRNA 961insC、T1095C、C1494T、A1555G 4种不同突变的4例外周血DNA样本和4例正常对照标本经测序验证,PCR扩增靶序列,设计延伸引物,延伸后得到线粒体DNA 12SrRNA基因961insC、T1095C、C1494T、A1555G 4个常见突变的特异性延伸片段,用全变性高效液相色谱分析延伸片段混合物,分离图谱鉴定被检样本的基因型。结果 4例包含线粒体DNA 12SrRNA基因4种耳聋相关突变的DNA样本均扩增出包含4种突变的975 bp特征性条带,PE-DHPLC检测结果显示突变者有引物峰和突变峰两个峰,完全可以鉴别出4种突变,而4例正常对照标本仅显示单个引物峰。结论本实验建立了Primer Extension-DHPLC的线粒体相关耳聋突变分析新方法,可用于耳聋的基因诊断。 展开更多
关键词 线粒体DNA12SrRNA 耳聋 基因突变 变性高效液相色谱 引物延伸
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Extension测度和Fuzzy-Extension变换测度及其积分 被引量:2
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作者 仇计清 《河北轻化工学院学报》 1993年第2期5-11,共7页
提出Extension测度、Extension积分、Fuzzy-Extension变换测度、Fuzzy-Extension变换积分等概念,它们是解决度量领域内不相容问题的重要研究课题。在建立解决量子检测与估值中不相容问题的数学模型方面取得一定进展。
关键词 测度 模糊 扩张 变换 积分
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人参皂苷Rc通过调控AMPK通路介导的细胞焦亡减轻小鼠脑缺血再灌注损伤
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作者 李良勇 马莉 +1 位作者 李亚军 梅灯 《中国病理生理杂志》 CAS CSCD 北大核心 2024年第5期844-851,共8页
目的:探讨人参皂苷Rc对脑缺血再灌注损伤(CIRI)小鼠的保护作用,并从细胞焦亡角度阐释其作用机制。方法:将C57BL/6小鼠随机分为假手术(sham)组、大脑中动脉闭塞/再灌注(MCAO/R)组、人参皂苷Rc+MCAO/R组(Rc组)、AMP活化蛋白激酶(AMPK)激... 目的:探讨人参皂苷Rc对脑缺血再灌注损伤(CIRI)小鼠的保护作用,并从细胞焦亡角度阐释其作用机制。方法:将C57BL/6小鼠随机分为假手术(sham)组、大脑中动脉闭塞/再灌注(MCAO/R)组、人参皂苷Rc+MCAO/R组(Rc组)、AMP活化蛋白激酶(AMPK)激动剂阿卡地新(AICAR)+MCAO/R组(agonist组)和人参皂苷Rc+MCAO/R+AMPK抑制剂Compound C组(Rc+inhibitor组)。对agonist组小鼠给予AICAR(500 mg/kg)腹腔注射,Rc+inhibitor组小鼠给予Compound C(20 mg/kg)腹腔注射;Rc组和Rc+inhibitor组小鼠造模后给予人参皂苷Rc(40 mg/kg)灌胃,每天一次,连续7 d;sham组和MCAO/R组则给予等体积的纯化水。Zea Longa评分观察小鼠神经功能缺损程度,TTC染色观察小鼠脑梗死体积,干湿重法观察小鼠脑水肿程度,HE染色观察小鼠脑组织病理形态的改变,RT-qPCR和Western blot检测小鼠脑组织AMPK、核苷酸结合寡聚化结构域样受体蛋白3(NLRP3)、胱天蛋白酶1(caspase-1)和焦亡效应蛋白消皮素D(GSDMD)的表达,ELISA检测炎症因子白细胞介素1β(IL-1β)和IL-18的含量。结果:Rc组和agonist组小鼠神经功能缺损症状减轻,脑梗死体积减小,脑水肿和神经元病理损伤受到抑制,脑组织pAMPK/AMPK比值和AMPK mRNA表达水平升高,细胞焦亡相关蛋白NLRP3、caspase-1和GSDMD的mRNA和蛋白表达水平降低,炎症因子IL-1β和IL-18表达水平降低。Rc+inhibitor组小鼠脑组织p-AMPK/AMPK比值和AMPK mRNA表达水平较Rc组显著下降(P<0.05),NLRP3、caspase-1和GSDMD的mRNA和蛋白表达水平,以及IL-1β和IL-18表达水平显著升高(P<0.05),小鼠神经功能缺损程度评分升高,脑梗死体积增大,脑水肿和神经元病理损伤显著加重(P<0.05)。结论:人参皂苷Rc可能通过活化AMPK通路抑制NLRP3/caspase-1/GSDMD介导的细胞焦亡,从而减轻小鼠CIRI。 展开更多
关键词 人参皂苷Rc 脑缺血再灌注损伤 amp活化蛋白激酶 细胞焦亡
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黄芩苷调节cAMP/PKA/CREB信号通路对湿疹大鼠皮肤屏障功能的影响 被引量:3
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作者 王首帆 徐宜厚 +1 位作者 徐爱琴 朱立宏 《天津医药》 CAS 2024年第2期148-153,共6页
目的探讨黄芩苷(BA)调节环磷酸腺苷(cAMP)/蛋白激酶A(PKA)/cAMP反应元件结合蛋白(CREB)通路对湿疹大鼠皮肤屏障功能的影响。方法将SD大鼠随机分为对照组(NC组)、Model组、低剂量BA组(BA-L组,25 mg/kg)、中剂量BA组(BA-M组,50 mg/kg)、... 目的探讨黄芩苷(BA)调节环磷酸腺苷(cAMP)/蛋白激酶A(PKA)/cAMP反应元件结合蛋白(CREB)通路对湿疹大鼠皮肤屏障功能的影响。方法将SD大鼠随机分为对照组(NC组)、Model组、低剂量BA组(BA-L组,25 mg/kg)、中剂量BA组(BA-M组,50 mg/kg)、高剂量BA组(BA-H组,100 mg/kg)、泼尼松组(PNS组,25 mg/kg)、BAH+cAMP抑制剂(SQ22536)组(100 mg/kg+2.13 mg/kg)、BA-H+PKA抑制剂(H-89)组(100 mg/kg+5 mg/kg),每组12只。除NC组外,其余组大鼠均构建湿疹大鼠模型。建模成功2 d后,分组进行给药处理。检测湿疹面积及严重度指数(EASI)评分、经皮肤水分流失量(TEWL)、角质层含水量(WCSC)变化;酶联免疫吸附试验(ELISA)检测大鼠血清中免疫球蛋白E(IgE)、干扰素-γ(IFN-γ)、白细胞介素-4(IL-4)水平及大鼠背部受试区皮损组织中c AMP蛋白表达;HE染色检测大鼠背部受试区皮损组织病理变化;Western blot检测大鼠背部受试区皮损组织中水通道蛋白3(AQP3)、cathelicidin相关抗菌肽(CRAMP)、p-PKA、p-CREB蛋白表达。结果与NC组比较,Model组大鼠背部受试区皮损组织病理损伤严重,EASI评分、TEWL、IgE、IL-4水平升高,WCSC、IFN-γ水平、AQP3、CRAMP、cAMP、p-PKA、p-CREB蛋白水平降低(P<0.05)。与Model组比较,BA-L组、BA-M组、BA-H组、PNS组大鼠背部受试区皮损组织病理损伤减轻,EASI评分、TEWL、IgE、IL-4水平降低,WCSC、IFN-γ水平、AQP3、CRAMP、cAMP、p-PKA、p-CREB蛋白水平升高(P<0.05);且BA-L组、BA-M组、BA-H组上述指标变化呈剂量依赖性。SQ22536或H-89减弱了高剂量BA对湿疹大鼠皮肤屏障功能的改善作用。结论BA可能通过激活cAMP/PKA/CREB信号通路改善湿疹大鼠皮肤屏障功能。 展开更多
关键词 湿疹 黄芩苷 环磷酸腺苷/蛋白激酶A/camp反应元件结合蛋白通路 皮肤屏障功能
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LIBERAL EXTENSIONS 和反单本原根
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作者 魏俊潮 陈建华 《数学杂志》 CSCD 1998年第1期5-8,共4页
设R≤T≤S,其中S是R的LiberalExtensionsandT是R的IntermediateExtension我们证明了下面等式:s(S)∩R=s(R)=s(T)∩R,且s(T)n≤s(S).其中S可为反单本原... 设R≤T≤S,其中S是R的LiberalExtensionsandT是R的IntermediateExtension我们证明了下面等式:s(S)∩R=s(R)=s(T)∩R,且s(T)n≤s(S).其中S可为反单本原根或反单根。 展开更多
关键词 反单本原根 亚直既约环 结合环 自由扩张
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