期刊文献+
共找到2,152篇文章
< 1 2 108 >
每页显示 20 50 100
Nuclear heating at the JSI TRIGA reactor:measurements and simulations
1
作者 Klemen Ambrožič Hubert Carcreff +4 位作者 Vladimir Radulović Damien Fourmentel Christophe Destouches Nicolas Thiollay Luka Snoj 《Nuclear Science and Techniques》 2026年第4期243-253,共11页
Nuclear heating plays an important aspect in design and deployment of both fission and fusion reactors and experimental devices in terms of cooling requirements. Two experimental campaigns in the framework of a collab... Nuclear heating plays an important aspect in design and deployment of both fission and fusion reactors and experimental devices in terms of cooling requirements. Two experimental campaigns in the framework of a collaboration project between the French Atomic and Alternative Energy Commission(CEA) and Jožef Stefan Institute(JSI), Slovenia, have been performed at the JSI TRIGA reactor for the experimental assessment of nuclear heating in fission and fusion-relevant materials by the differential calorimetry technique, based on the CALMOS and CARMEN differential calorimeters, previously developed at CEA. The results of the first campaign performed at reactor powers between 100 and 250 kW have already been reported, highlighting some measurement difficulties. Therefore, the second campaign was performed at a lower reactor power of 30 kW to overcome these issues. Moreover, a computational analysis of the experiments was performed using the JSIR2S code package to calculate the nuclear heating levels. Both experiments and their reproduction by simulations are described in detail. We present a comparison of the previously reported measured nuclear heating values of the first campaign with the computational results, with consistent underestimation by simulations by 8–35%. We report the experimental and computational results for the second experimental campaign performed at a reactor power of 30 kW. The simulated heating values were in agreement with the measurements within the measured heating uncertainty, with simulated heating 2.7–11.3% lower than the experimental values. 展开更多
关键词 Nuclear heating Differential calorimeter R2S MCNP Eurofer97 TUNGSTEN
在线阅读 下载PDF
Systematic study of laser-assisted cluster radioactivity for deformed nuclei
2
作者 Leng-Jun Liao Lin-Jing Qi +2 位作者 Xi-Jun Wu Xiao-Hua Li Ming Li 《Nuclear Science and Techniques》 2026年第4期232-242,共11页
In this study,the effects of laser fields that can be achieved in the near future on cluster penetration probability and half-life are quantitatively investigated.The calculation results show that extreme laser fields... In this study,the effects of laser fields that can be achieved in the near future on cluster penetration probability and half-life are quantitatively investigated.The calculation results show that extreme laser fields can slightly change the cluster-decay half-life by affecting the penetration probability within a narrow range.Subsequently,we discuss the correlation between the change rate of the penetration probability and the tunneling path.The results indicate that for different parent nuclei emitting the same cluster,nuclei with longer tunneling paths are more easily affected by the laser fields.The shell effect on this correlation is also observed.In addition,the impact of laser fields on the penetration probability in any direction is investigated. 展开更多
关键词 Cluster radioactivity HALF-LIFE Extreme laser field Penetration probability
在线阅读 下载PDF
The Swimming Performance of Mollies and Their Interaction with Tiger Barb Fish when Exposed to Concurrent Low pH and Elevated Temperature
3
作者 Rostern Tembo 《Journal of Environmental Science and Engineering(B)》 2025年第3期96-102,共7页
The global climate change and ocean acidification brought about by the anthropogenic release of carbon dioxide gas into the air is considered one of the greatest problems facing marine life.In this research,the intera... The global climate change and ocean acidification brought about by the anthropogenic release of carbon dioxide gas into the air is considered one of the greatest problems facing marine life.In this research,the interactions between two species of fish(the gold mollies and tiger barb)were investigated under two different environmental conditions,an elevated temperature of 28℃ and a low pH of 5 and a normal pH of 7 and a normal temperature of 24℃.The mollies at pH 7 and a temperature of 24℃ exhibited scary interactions with the tiger barb.They were scared and ran fast away from the tiger barb.At the same time,the mollies at pH 5 and a temperature of 28℃ interacted normally as though both species were one species showing behavioral changes due to these two stressors(pH 5 and elevated temperature 28℃).This could be the only research that has addressed how the kinematics and swimming interactions of two species of fish changed in response to elevated temperature and low pH. 展开更多
关键词 pH 5 pH 7 temperature of 28℃ temperature of 24℃ gold mollies tiger barb
在线阅读 下载PDF
Pricing Multi-Strike Quanto Call Options on Multiple Assets with Stochastic Volatility, Correlation, and Exchange Rates
4
作者 Boris Ter-Avanesov Gunter Meissner 《Applied Mathematics》 2025年第1期113-142,共30页
Quanto options allow the buyer to exchange the foreign currency payoff into the domestic currency at a fixed exchange rate. We investigate quanto options with multiple underlying assets valued in different foreign cur... Quanto options allow the buyer to exchange the foreign currency payoff into the domestic currency at a fixed exchange rate. We investigate quanto options with multiple underlying assets valued in different foreign currencies each with a different strike price in the payoff function. We carry out a comparative performance analysis of different stochastic volatility (SV), stochastic correlation (SC), and stochastic exchange rate (SER) models to determine the best combination of these models for Monte Carlo (MC) simulation pricing. In addition, we test the performance of all model variants with constant correlation as a benchmark. We find that a combination of GARCH-Jump SV, Weibull SC, and Ornstein Uhlenbeck (OU) SER performs best. In addition, we analyze different discretization schemes and their results. In our simulations, the Milstein scheme yields the best balance between execution times and lower standard deviations of price estimates. Furthermore, we find that incorporating mean reversion into stochastic correlation and stochastic FX rate modeling is beneficial for MC simulation pricing. We improve the accuracy of our simulations by implementing antithetic variates variance reduction. Finally, we derive the correlation risk parameters Cora and Gora in our framework so that correlation hedging of quanto options can be performed. 展开更多
关键词 Quanto Option Multi-Strike Option Stochastic Volatility (SV) Stochastic Correlation (SC) Stochastic Exchange Rates (SER) CORA GORA Correlation Risk
在线阅读 下载PDF
Prediction and Modelling of Land Use Change in Pesawaran District Lampung Using ANN and Cellular Automata
5
作者 Irma Lusi Nugraheni Mustofa Usman Sutarto Sutarto 《Journal of Environmental & Earth Sciences》 2025年第6期46-62,共17页
The simultaneous increase in development in Pesawaran Regency is closely correlated with the intense competi-tion for land use.However,low policy implementation effectiveness has led to construction beyond designated ... The simultaneous increase in development in Pesawaran Regency is closely correlated with the intense competi-tion for land use.However,low policy implementation effectiveness has led to construction beyond designated spatial plan.The study used a quantitative survey using Landsat images in 2016,2019,and 2022.The data analysis techniques used geographic information systems integrated with Artificial Neural Network(ANN)and Cellular Automata(CA)models.This study aims to predict land-use change in 2031,evaluate its alignment with spatial planning,and provide guidance for controlling land-use change.The results showed that there has been an increase in land use.In 2019,built-up land reached 7,069.65 Ha.The model shows its ability to predict land simulation and transformation,where it is predicted that built-up land in 2031 will experience an increase of up to 40.10%,so development and change cannot be avoided every year.This study also suggests that decision-makers and local governments should reconsider spatial planning strategies.This study shows that there have been many land use changes from 2016 to 2022.The model shows its ability to predict simulation and land transformation.When using the model,there are many changes in the land use area in 2031.This is due to wet agricultural land turning into built-up land by almost 70%.This study shows that road network influence land-use change.The cellular automata model managed to capture the complexity with simple rules.Predictions for future research should focus on conserving wetlands and primary forests. 展开更多
关键词 Land Use Model System Information Geography Cellular Automata Artificial Neural Network(ANN)
在线阅读 下载PDF
Mars Clocks and other novel analog clocks,using Earth Standard Seconds
6
作者 Eric Wim Flesch Reggis Eric Sanders 《Astronomical Techniques and Instruments》 2025年第3期210-217,共8页
We present analog clocks fitted to the Mars solar day.These clocks use the standard Earth-based second of the International System of Units(SI)as their operational unit of time,unlike current practice for Mars timekee... We present analog clocks fitted to the Mars solar day.These clocks use the standard Earth-based second of the International System of Units(SI)as their operational unit of time,unlike current practice for Mars timekeeping.We discuss the importance of preserving the SI second.On this basis,we identify the two analog clocks most suitable for public use by a future Mars population.These are a 20-hour clock with a hand motion similar to that of the standard Earth clock,and a 24-hour clock with a novel“Martian”hand motion which strikes the hour when all 3 hands converge onto that hour mark on the dial.Both clocks have Earth-day equivalents to assist learning.We also present a 24-hour“SpaceClock”,similar to the Martian clock but with no favored reference plane,hence equally readable from any viewing orientation. 展开更多
关键词 CLOCK MARS
在线阅读 下载PDF
Introduction to the Special Issue on Analytical and Numerical Solution of the Fractional Differential Equation
7
作者 Ndolane Sene Ameth Ndiaye 《Computer Modeling in Engineering & Sciences》 2025年第12期2849-2852,共4页
Fractional differential equations have garnered significant attention within the mathematical and physical sciences due to the diverse range of fractional operators available.Fractional calculus has demonstrated its u... Fractional differential equations have garnered significant attention within the mathematical and physical sciences due to the diverse range of fractional operators available.Fractional calculus has demonstrated its utility across various disciplines,including biological modeling[1–5],applications in physics[6,7],most notably in the formulation of fractional diffusion equations,in robotics,and emerging areas such as intelligent artificial systems,among others.Numerous types of fractional operators exist,including those characterized by singular kernels,such as the Caputo and Riemann-Liouville derivatives[8,9].It is important to highlight that the Riemann-Liouville derivative exhibits certain limitations;most notably,the derivative of a constant is not zero,which poses a significant inconvenience.To circumvent this issue,the Caputo derivative was introduced.Additionally,there are fractional derivatives with non-singular kernels,such as the Caputo-Fabrizio derivative[10]and the Atangana-Baleanu fractional derivative[11],each providing unique advantages for modeling purposes.Given the growing interest in utilizing fractional operators for various modeling scenarios,it is imperative to propose robust methodologies for obtaining both approximate and exact solutions.Consequently,this special issue emphasizes the exploration of diverse numerical schemes aimed at deriving approximate solutions for the models under consideration.Furthermore,analytical methods have also been discussed,providing additional avenues for obtaining exact solutions. 展开更多
关键词 mathematical physical sciences numerical solutions fractional diffusion equationsin fractional operators fractional differential equations analytical solutions intelligent artificial systemsamong
在线阅读 下载PDF
Digital Twins and Cyber-Physical Systems:A New Frontier in Computer Modeling
8
作者 Vidyalakshmi G S Gopikrishnan +2 位作者 Wadii Boulila Anis Koubaa Gautam Srivastava 《Computer Modeling in Engineering & Sciences》 2025年第4期51-113,共63页
Cyber-Physical Systems(CPS)represent an integration of computational and physical elements,revolutionizing industries by enabling real-time monitoring,control,and optimization.A complementary technology,Digital Twin(D... Cyber-Physical Systems(CPS)represent an integration of computational and physical elements,revolutionizing industries by enabling real-time monitoring,control,and optimization.A complementary technology,Digital Twin(DT),acts as a virtual replica of physical assets or processes,facilitating better decision making through simulations and predictive analytics.CPS and DT underpin the evolution of Industry 4.0 by bridging the physical and digital domains.This survey explores their synergy,highlighting how DT enriches CPS with dynamic modeling,realtime data integration,and advanced simulation capabilities.The layered architecture of DTs within CPS is examined,showcasing the enabling technologies and tools vital for seamless integration.The study addresses key challenges in CPS modeling,such as concurrency and communication,and underscores the importance of DT in overcoming these obstacles.Applications in various sectors are analyzed,including smart manufacturing,healthcare,and urban planning,emphasizing the transformative potential of CPS-DT integration.In addition,the review identifies gaps in existing methodologies and proposes future research directions to develop comprehensive,scalable,and secure CPSDT systems.By synthesizing insights fromthe current literature and presenting a taxonomy of CPS and DT,this survey serves as a foundational reference for academics and practitioners.The findings stress the need for unified frameworks that align CPS and DT with emerging technologies,fostering innovation and efficiency in the digital transformation era. 展开更多
关键词 Cyber physical systems digital twin efficiency Industry 4.0 robustness and intelligence
在线阅读 下载PDF
Multimodal Learning in Image Processing
9
作者 Zhixin Chen Gautam Srivastava Shuai Liu 《Computers, Materials & Continua》 2025年第2期3615-3618,共4页
1 Introduction onMultimodal Learning in Image Processing IP(Image processing),as a classical research domain in computer application technology,has been researched for decades.It is one of the most important research ... 1 Introduction onMultimodal Learning in Image Processing IP(Image processing),as a classical research domain in computer application technology,has been researched for decades.It is one of the most important research directions in computer vision,which is the basis for many current hotspots such as intelligent transportation/education/industry,etc.Because image processing is the strongest link for AI(artificial intelligence)applying to real world application,it has been a challenging research field with the development of AI,from DNN(deep convolutional network),Attention/LSTM(long-short term memory),to Transformer/Diffusion/Mamba based GAI(generated AI)models,e.g.,GPT and Sora[1].Today,the description ability of single-model feature limits the performance of image processing.More comprehensive description of the image is required to match the computational performance of current large scale models. 展开更多
关键词 IMAGE COMPUTER LSTM
在线阅读 下载PDF
Distribution and human health risk assessment of cadmium,arsenic,mercury,lead,and iron in settling particles from the transboundary estuary in three rivers of Cote d’Ivoire,West Africa
10
作者 Dehoule N’Guessan Fulgence Kouassi Assy Eudes Yapi +2 位作者 N’Guessan Louis Berenger Kouassi Koffi Marcellin Yao Aoua Sougo Coulibaly 《Acta Geochimica》 2025年第5期1040-1058,共19页
Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic... Pollution of transboundary rivers can result from anthropogenic activities in their watersheds.In this study,sediment traps were deployed to determine the fluxes,concentrations,and health risks associated with arsenic,cadmium,mercury,lead,and iron in the estuaries of three transboundary rivers(Comoé,Bia,and Tanoé)in West Africa.Thus,the analysis of metal-associated sedimentation particle samples collected in rainy,flood,and dry seasons was required.Sediment traps were used to calculate the metal fluxes associated with sedimentation particles towards the Atlantic Ocean.Finally,the carcinogenic and non-carcinogenic risks of ingestion and dermal contact associated with sedimentation particles were assessed.The results showed that the total concentrations of trace metals in particulate matter were higher than in the UCC(Upper Crust Continental),with the exception of lead.The highest fluxes of lead,mercury,iron and arsenic associated with sedimented particles were observed during flood periods in the estuary of the Comoé,Bia and Tanoérivers.Cadmium fluxes associated with sedimentation particles were highest in the rainy season in the Bia and Comoéestuaries and in the flood season in the Tanoéestuary.Pearson’s correlation analysis and the enrichment factor showed that the trace metals were derived from anthropogenic activities such as mining and farming.In addition,contamination indices showed that sediment particles in the estuaries of the three rivers were severely contaminated with mercury.However,the results of potential human health risks associated with trace metals show that there is no probability of exposure of the community to harmful and carcinogenic effects through ingestion and dermal absorption of sediment particles.It is essential to integrate the information from this study into policy-and decision-making processes for better management of transboundary river water resources in coastal countries,particularly the Côte d’Ivoire. 展开更多
关键词 Trace metals Settling particles Transboundary rivers Carcinogenic and non-carcinogenic risks ESTUARY West Africa
在线阅读 下载PDF
Use of supervised and unsupervised approaches to make zonal application maps for variable-rate application of crop growth regulators in commercial cotton fields
11
作者 ANDREA Maria C.da S. OLIVEIRA Cristiano F.de +7 位作者 MOTA Fabrícia C.M. SANTOS Rafael C.dos RODRIGUES JUNIOR Edilson F. BIANCHI Lucas M. OLIVEIRA Rodrigo S.de GOUVEIA Caio M.de BARBOSA Victor G.S. BISPO E SILVA Marco A. 《Journal of Cotton Research》 2025年第1期1-20,共20页
Background Zonal application maps are designed to represent field variability using key variables that can be translated into tailored management practices.For cotton,zonal maps for crop growth regulator(CGR)applicati... Background Zonal application maps are designed to represent field variability using key variables that can be translated into tailored management practices.For cotton,zonal maps for crop growth regulator(CGR)applications under variable-rate(VR)strategies are commonly based exclusively on vegetation indices(VIs)variability.However,VIs often saturate in dense crop vegetation areas,limiting their effectiveness in distinguishing variability in crop growth.This study aimed to compare unsupervised framework(UF)and supervised framework(SUF)approaches for generat-ing zonal application maps for CGR under VR conditions.During 2022-2023 agricultural seasons,an UF was employed to generate zonal maps based on locally collected field data on plant height of cotton,satellite imagery,soil texture,and phenology data.Subsequently,a SUF(based on historical data between 2020-2021 to 2022-2023 agricultural seasons)was developed to predict plant height using remote sensing and phenology data,aiming to replicate same zonal maps but without relying on direct field measurements of plant height.Both approaches were tested in three fields and on two different dates per field.Results The predictive model for plant height of SUF performed well,as indicated by the model metrics.However,when comparing zonal application maps for specific field-date combinations,the predicted plant height exhibited lower variability compared with field measurements.This led to variable compatibility between SUF maps,which utilized the model predictions,and the UF maps,which were based on the real field data.Fields characterized by much pronounced soil texture variability yielded the highest compatibility between the zonal application maps produced by both SUF and UF approaches.This was predominantly due to the greater consistency in estimating plant development patterns within these heterogeneous field environments.While VR application approach can facilitate product savings during the application operation,other key factors must be considered.These include the availability of specialized machinery required for this type of applications,as well as the inherent operational costs associated with applying a single CGR product which differs from the typical uniform rate applications that often integrate multi-ple inputs.Conclusion Predictive modeling shows promise for assisting in the creation of zonal application maps for VR of CGR applications.However,the degree of agreement with the actual variability in crop growth found in the field should be evaluated on a field-by-field basis.The SUF approach,which is based on plant heigh prediction,demonstrated potential for supporting the development of zonal application maps for VR of CGR applications.However,the degree to which this approach aligns itself with the actual variability in crop growth observed in the field may vary,necessi-tating field-by-field evaluation. 展开更多
关键词 Cotton Site-specific management Crop growth regulator Unsupervised framework Supervised framework Zonal application maps
在线阅读 下载PDF
Water Erosion Factors Modeling in the N’Zérékoré City, Republic of Guinea
12
作者 Alhassane Diallo Oumar Keita +1 位作者 Ibrahima Sory Mamikouny CAMARA Boubacar Diallo 《Journal of Environmental Science and Engineering(A)》 2025年第4期206-216,共11页
Soil erosion from water has become a relevant issue at global level.In Guinea in particular,erosion has worrying effects,due to natural conditions and human impact,especially in the Nzérékore city in forest ... Soil erosion from water has become a relevant issue at global level.In Guinea in particular,erosion has worrying effects,due to natural conditions and human impact,especially in the Nzérékore city in forest region.This paper proposed a soil erosion modeling by rainfall effect in the prefecture of N'Zérékoré.To achieve this objective,monthly and annual rainfall data for the N'Zérékorécity were collected at the meteorological station over the period from 1980 to 2024.The analysis of rainfall aggressiveness was possible using the Fournier index.For data processing,we used Microsoft Excel,Python and the ARIMA(AutoRegressive Integrated Moving Average)model for soil aggressiveness predicted by rainfall.It was found that,from 2000 to 2009,erosion was higher compared to other periods with a rate of 60%,or 6 years of high rainfall aggression.From the periods 1990 to 1999 and 2010 to 2019,the lowest rainfall aggressiveness was recorded,with 60%or 6 years of low erosivity.However,from period 1980 to 1989 the highest rate(70%)of very high rainfall erosivity was recorded.The results show three levels of rainfall aggressiveness on an annual scale:a very high level of erosivity with a rate of 22.2%or 10 years,followed by a high level of 35.6%or 16 years of strong erosion.The moderate erosivity level corresponds to 42.2%or 19 years.The model predicts a stability of the erosivity index around 77.14 over the period 2025-2034.During the forty(45)years the rainfall erosivity index was very unstable characterized by strong erosion,however it would be stable in the next ten(10)years. 展开更多
关键词 Rainfall factor water erosion erosivity index N’Zérékoré
在线阅读 下载PDF
Role of deep learning in cognitive healthcare:Wearable signal analysis,algorithms,benefits,and challenges
13
作者 Md.Sakib Bin Alam Aiman Lameesa +4 位作者 Senzuti Sharmin Shaila Afrin Shams Forruque Ahmed Mohammad Reza Nikoo Amir H.Gandomi 《Digital Communications and Networks》 2025年第3期642-670,共29页
Deep Learning(DL)offers promising solutions for analyzing wearable signals and gaining valuable insights into cognitive disorders.While previous review studies have explored various aspects of DL in cognitive healthca... Deep Learning(DL)offers promising solutions for analyzing wearable signals and gaining valuable insights into cognitive disorders.While previous review studies have explored various aspects of DL in cognitive healthcare,there remains a lack of comprehensive analysis that integrates wearable signals,data processing techniques,and the broader applications,benefits,and challenges of DL methods.Addressing this limitation,our study provides an extensive review of DL’s role in cognitive healthcare,with a particular emphasis on wearables,data processing,and the inherent challenges in this field.This review also highlights the considerable promise of DL approaches in addressing a broad spectrum of cognitive issues.By enhancing the understanding and analysis of wearable signal modalities,DL models can achieve remarkable accuracy in cognitive healthcare.Convolutional Neural Network(CNN),Recurrent Neural Network(RNN),and Long Short-term Memory(LSTM)networks have demonstrated improved performance and effectiveness in the early diagnosis and progression monitoring of neurological disorders.Beyond cognitive impairment detection,DL has been applied to emotion recognition,sleep analysis,stress monitoring,and neurofeedback.These applications lead to advanced diagnosis,personalized treatment,early intervention,assistive technologies,remote monitoring,and reduced healthcare costs.Nevertheless,the integration of DL and wearable technologies presents several challenges,such as data quality,privacy,interpretability,model generalizability,ethical concerns,and clinical adoption.These challenges emphasize the importance of conducting future research in areas such as multimodal signal analysis and explainable AI.The findings of this review aim to benefit clinicians,healthcare professionals,and society by facilitating better patient outcomes in cognitive healthcare. 展开更多
关键词 Cognitive healthcare Deep learning Wearable sensor Convolutional neural network Recurrent neural network
暂未订购
内蒙古中西部地区不同土壤类型下土壤水分的研究 被引量:15
14
作者 李宁 顾卫 +3 位作者 杜子璇 史培军 任学慧 Kevin Levy 《地球科学进展》 CAS CSCD 北大核心 2006年第2期151-156,共6页
以2002—2003年连续两年自行观测的内蒙古中西部地区二连浩特、乌拉特中旗和乌海的土壤水分为基础,重点分析了沙尘暴发生季节反映下垫面特征的土壤水分的时间变化以及大气影响对不同土壤类型(棕钙土,灰漠土,栗钙土)水分的作用。土壤水... 以2002—2003年连续两年自行观测的内蒙古中西部地区二连浩特、乌拉特中旗和乌海的土壤水分为基础,重点分析了沙尘暴发生季节反映下垫面特征的土壤水分的时间变化以及大气影响对不同土壤类型(棕钙土,灰漠土,栗钙土)水分的作用。土壤水分的变化被分为3个阶段进行分析,分别是解冻期至沙尘暴开始的春季、雨期的秋季和冰雪覆盖的冬季。土壤水分受气象条件和土壤类型的影响较大。在气象条件的影响下,土壤水分含量在土壤融化期最低,在雨季达到最大值,其中以栗钙土受的影响最明显。沙尘暴发生依赖于土壤融化时间、土壤融化期的土壤条件和上年冬季的冻土深度。 展开更多
关键词 土壤水分 土壤温度 风速 沙尘暴 干旱与半干旱气候
在线阅读 下载PDF
松潘-甘孜造山带鲜水河断裂与雅拉雪山片麻岩穹窿的关系 被引量:6
15
作者 吴婵 许志琴 +3 位作者 A.A.G.WEBB 董汉文 曹汇 程展展 《地质学报》 EI CAS CSCD 北大核心 2016年第11期2982-2998,共17页
片麻岩穹窿是岩浆作用、变质作用和变形作用的共同结果,是造山带的重要构造元素。本次在松潘一甘孜地体内鲜水河大型左旋走滑断裂带北东侧雅拉雪山发现一个片麻岩穹窿,核部为弱面理化花岗岩,边部为面理化花岗岩,紧邻断裂带的花岗岩... 片麻岩穹窿是岩浆作用、变质作用和变形作用的共同结果,是造山带的重要构造元素。本次在松潘一甘孜地体内鲜水河大型左旋走滑断裂带北东侧雅拉雪山发现一个片麻岩穹窿,核部为弱面理化花岗岩,边部为面理化花岗岩,紧邻断裂带的花岗岩发生糜棱岩化。锆石LA—ICP—MSUPb测年结果表明,雅拉雪山片麻岩穹窿核部弱面理化花岗岩和边部面理化花岗岩的锆石U—Pb年龄分别为14.51±O.82Ma,14.39±0.23Ma,14.25±0.34Ma和18.2±1.3Ma,因此,该片麻岩穹窿形成于18~14Ma。鲜水河剪切带中的糜棱岩以及花岗岩脉的锆石U—Pb年龄分别为14.57±0.34Ma和16.73±0.97Ma,代表断裂剪切作用时代。该片麻岩穹窿的形成时代与鲜水河断裂带的活动时代基本一致,它是鲜水河断裂带在左行剪切作用过程中岩体部分熔融,并在转化挤压作用下隆升形成的。它的形成代表了鲜水河断裂深部的剪切作用时代,深部的剪切熔融促使了断裂带向南东方向扩展,促进了川滇地块的旋转运动,调节了青藏高原物质的东移,进一步促使了青藏高原东缘上地壳加厚和山脉隆升以及河流下切作用,使片麻岩穹窿分别在12~5.5Ma和4.4~3.1Ma期间,发生快速冷却,冷却速率分别为~61℃/Ma和~146℃/Ma。 展开更多
关键词 U—Pb年代学 片麻岩穹窿 鲜水河断裂 松潘一甘孜造山带
在线阅读 下载PDF
映射芽的相对无穷小稳定开折的唯一性 被引量:2
16
作者 石昌梅 熊宗洪 陈松良 《高校应用数学学报(A辑)》 CSCD 北大核心 2018年第3期265-271,共7页
借助于映射芽稳定性问题的研究方法,定义了映射芽的相对无穷小稳定,证明了映射芽的相对无穷小稳定开折在相对左右等价下是唯一的,这是研究相对稳定映射芽分类问题的一个理论基础,同时也补充了奇点理论在相对意义下的一些结果.
关键词 映射芽 开折 相对等价关系 相对无穷小稳定 唯一性
在线阅读 下载PDF
一类修正的Lupas-Durrmeyer型算子的逼近性质研究 被引量:1
17
作者 连博勇 蔡清波 《高校应用数学学报(A辑)》 CSCD 北大核心 2018年第1期99-104,共6页
引入了一类修正的Lupas-Durrmeyer型算子,该算子不仅常数保持还线性保持.利用连续模,光滑模和K-泛函,讨论了该算子的某些逼近性质.最后还给出了该算子对Lipschitz函数类的逼近及Voronvskaya型渐近展开公式.
关键词 Lupas-Durrmeyer型算子 K-泛函 连续模 Voronvskaya型渐近展开公式
在线阅读 下载PDF
有界解析函数的n阶导数估计 被引量:2
18
作者 戴绍虞 潘一飞 《数学杂志》 CSCD 北大核心 2010年第2期296-302,共7页
本文研究了有界解析函数的n阶导数估计.利用有界解析函数泰勒展开式的系数估计,得到了n阶导数估计的一般式,改进了已有的相关结果.
关键词 有界解析函数 导数估计
在线阅读 下载PDF
一类变指数椭圆系统的多重解 被引量:1
19
作者 张申贵 《高校应用数学学报(A辑)》 北大核心 2019年第4期420-428,共9页
利用变指数Sobolev空间理论和临界点理论中的Clark定理,研究一类变指数椭圆系统的边值问题.当非线性项在零点附近p--次线性增长时,得到该系统无穷多个解的存在性.
关键词 椭圆系统 p(x)-拉普拉斯算子 p(x)-双调和算子 临界点理论
在线阅读 下载PDF
具正负系数的二阶非线性中立型时滞差分方程的非振动准则 被引量:4
20
作者 杨甲山 方彬 《邵阳学院学报(自然科学版)》 2011年第1期1-4,共4页
近年来,随着科学技术的发展,差分方程理论不仅在物理学、航天卫星等领域中有重要的应用,而且在经济学、生物学、控制理论等自然科学和社会科学领域也成为不可缺少的数学工具.而中立型差分方程的振动性与非振动性理论作为中立型差分方程... 近年来,随着科学技术的发展,差分方程理论不仅在物理学、航天卫星等领域中有重要的应用,而且在经济学、生物学、控制理论等自然科学和社会科学领域也成为不可缺少的数学工具.而中立型差分方程的振动性与非振动性理论作为中立型差分方程定性理论中的重要内容,更是受到了人们的普遍关注.本文研究了一类具有正负系数的二阶非线性中立型差分方程正解的存在性,利用Banach空间的不动点原理,结合一些分析技巧,得到了这类方程存在有界的最终正解的充分条件,推广并改进了现有文献中的结论.同时给出例子验证其有效性. 展开更多
关键词 正负系数 非线性 中立型时滞差分方程 不动点原理 最终正解
在线阅读 下载PDF
上一页 1 2 108 下一页 到第
使用帮助 返回顶部