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Second-order correlated interference with multi-wavelength thermal-light beams
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作者 De-Sheng Wang Yi-Ning Zhao +5 位作者 Lingxin Kong Su-Heng Zhang Chong Wang Cheng Ren Yuehua Su De-Zhong Cao 《Chinese Physics B》 2026年第2期374-382,共9页
A method for correlating thermal light over a wide spectral range is proposed.A multi-wavelength pseudothermal source,prepared by projecting laser beams of multiple wavelengths(650 nm,635 nm,532 nm,and 473 nm)onto a m... A method for correlating thermal light over a wide spectral range is proposed.A multi-wavelength pseudothermal source,prepared by projecting laser beams of multiple wavelengths(650 nm,635 nm,532 nm,and 473 nm)onto a moving thin ground glass plate,is employed in a double-slit interference experiment.The ground glass plate induces random phase differences between light beams of different wavelengths passing through it.This initial random phase difference significantly influences the high-order intensity correlation functions of multi-wavelength thermal beams.Experimentally,second-order correlated interference patterns,including subwavelength interference,of pseudothermal beams with different wavelengths are observed in the intensity correlation measurements.This method facilitates applications of correlated thermal photons in quantum information processing and quantum imaging. 展开更多
关键词 correlated interference multi-wavelength thermal light second-order correlation function
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A Fine-Grained RecognitionModel based on Discriminative Region Localization and Efficient Second-Order Feature Encoding
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作者 Xiaorui Zhang Yingying Wang +3 位作者 Wei Sun Shiyu Zhou Haoming Zhang Pengpai Wang 《Computers, Materials & Continua》 2026年第4期946-965,共20页
Discriminative region localization and efficient feature encoding are crucial for fine-grained object recognition.However,existing data augmentation methods struggle to accurately locate discriminative regions in comp... Discriminative region localization and efficient feature encoding are crucial for fine-grained object recognition.However,existing data augmentation methods struggle to accurately locate discriminative regions in complex backgrounds,small target objects,and limited training data,leading to poor recognition.Fine-grained images exhibit“small inter-class differences,”and while second-order feature encoding enhances discrimination,it often requires dual Convolutional Neural Networks(CNN),increasing training time and complexity.This study proposes a model integrating discriminative region localization and efficient second-order feature encoding.By ranking feature map channels via a fully connected layer,it selects high-importance channels to generate an enhanced map,accurately locating discriminative regions.Cropping and erasing augmentations further refine recognition.To improve efficiency,a novel second-order feature encoding module generates an attention map from the fourth convolutional group of Residual Network 50 layers(ResNet-50)and multiplies it with features from the fifth group,producing second-order features while reducing dimensionality and training time.Experiments on Caltech-University of California,San Diego Birds-200-2011(CUB-200-2011),Stanford Car,and Fine-Grained Visual Classification of Aircraft(FGVC Aircraft)datasets show state-of-the-art accuracy of 88.9%,94.7%,and 93.3%,respectively. 展开更多
关键词 Fine-grained recognition feature encoding data augmentation second-order feature discriminative regions
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Photo-crosslinked Second-order Nonlinear Optical Polymer Films with Large Nonlinear Optical Effect and High Thermostability
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作者 Pan-Pan Qiao Qian-Qian Li Zhen Li 《Chinese Journal of Polymer Science》 2026年第4期1007-1016,I0012,共11页
One of the most significant challenges in commercializing organic second-order nonlinear optical(NLO)materials lies in the inherent trade-off between nonlinearity and stability.A key factor in mitigating this compromi... One of the most significant challenges in commercializing organic second-order nonlinear optical(NLO)materials lies in the inherent trade-off between nonlinearity and stability.A key factor in mitigating this compromise is achieving precise temporal synchronization between the formation of the cross-linked network and the establishment of an optimal non-centrosymmetric alignment of the chromophores.Guided by this principle,we developed a series of NLO polymers incorporating multiple ether chains with low rotational energy barriers,which facilitate molecular reorientation during electric field poling,thereby enhancing the NLO response effectively.Combined with an optimized photocrosslinking strategy,the resulting PX4o/PETMP doped film achieved large macroscopic NLO coefficient of 190 pm·V^(-1)and thermal degradation temperature as high as 120℃.This work offers a universal approach to alleviating the“nonlinearity-stability”trade-off in a wide range of polymeric systems. 展开更多
关键词 second-order nonlinear optical effect Thermostability "Nonlinearity-stability"trade-off PHOTO-CROSSLINKING
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Effects of physical activity interventions on fundamental movement skills and cognitive function in early childhood:A systematic review and network meta-analysis
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作者 Shan Jiang Nan Zeng +4 位作者 Johan Y.Y.Ng Kar Hau Chong Taoran Zeng Suzannie K.Y.Leung Amy S.Ha 《Journal of Sport and Health Science》 2026年第3期37-50,共14页
Background:Health benefits have been reported for many physical activity(PA)interventions for improving fundamental movement skills(FMS)and cognitive function(CF),but the most effective type of PA interventions for em... Background:Health benefits have been reported for many physical activity(PA)interventions for improving fundamental movement skills(FMS)and cognitive function(CF),but the most effective type of PA interventions for emhancing FMS and CF in early childhood remain unknown.Thus,the study aimed to determine the effects of PA interventions in enhancing FMS and CF among young children and to establish the optimal types of PA interventions.Methods:Six electronic databases(PubMed,OVID,SPORTDiscus,Scopus,Web of Science,and Cochrane)were searched for studies from inception to March 17,2024.Randomized controlled trials(RCTs)were included in this study if they reported outcomes related to FMS,CF,or both associated with PA interventions.Effect sizes were calculated and performed as Hedges'g.The hierarchy of competing interventions was established using the surface under the cumulative ranking curve(SUCRA).Risk of bias was independently assessed using the Cochrane Riskof-Bias 2.Results:This analysis included 38 studies with 5237 young children,with sample sizes ranging from 32 to 897 participants.The types of PA interventions analyzed included active play/free play/unstructured PA(AP),general structured PA(GSPA),FMS-targeted PA programs(FMSprograms),cognitively-engaging PA programs(CPA),multilevel PA interventions(MPA),and exergaming.PA interventions had a large,pooled effect size for total FMS(g=0.96;95%CI:0.45-1.46;p<0.01;I^(2)=94%).For CF,a small-to-moderate pooled effect size was found(g=0.39;95%CI:0.18-0.60;p<0.01;I^(2)=88%).PA interventions longer than 3 months showed fewer benefits for FMS(p<0.01).The network meta-analysis showed that FMS-programs(standardized mean difference((SMD)=1.55,95%CI:0.98-2.11,SUCRA=98.3%)and GSPA(SMD=0.94,95%CI:0.05-1.85,SUCRA=69.8%)significantly improved total FMS compared to AP.For locomotor skills(LMS),exergaming ranked highest(SUCRA=79.3%),followed by FMS-programs(75.9%)and GSPA(61.6%).However,despite its top ranking,exergaming's effect estimate was not statistically significant(SMD=1.38,95%CI:-0.08 to 2.85).For object control skills(OCS),exergaming again ranked highest(SUCRA=91.9%)and showed the largest significant effect(SMD=2.38,95%CI:0.96-3.80),followed by FMS-programs(SUCRA=78.5%)and GSPA(SUCRA=53.7%).FMS-programs,GSPA,MPA,and UC also significantly improved OCS compared to AP.While no significant differences were observed across PA interventions for most CF domains,exergaming had a significant positive effect on working memory(SMD=1.41,95%CI:0.07-2.75).The certainty of evidence varied from low to moderate.Conclusion:These findings emphasize the importance of PA interventions in improving FMS and CF in early childhood.FMS-programs and GSPA appear to be the most effective approaches for enhancing total FMS,while exergaming showed the highest ranking for LMS and OCS,with a significant impact on OCS but uncertainty in LMS improvements.Additionally,exergaming had a positive effect on working memory,suggesting its potential cognitive benefits. 展开更多
关键词 Physical activity fundamental movement skills Cognitive function Early childhood
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Fundamental groups of manifolds of positive sectional curvature
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作者 RONG Xiaochun 《首都师范大学学报(自然科学版)》 2026年第1期1-13,27,共14页
Let M be a compact n-manifold of positive sectional curvature.We will review classical results on the fundamental group of M,a motivation on the c(n)-cyclic conjecture that the fundamental group of M contains a cyclic... Let M be a compact n-manifold of positive sectional curvature.We will review classical results on the fundamental group of M,a motivation on the c(n)-cyclic conjecture that the fundamental group of M contains a cyclic subgroup of index bounded above by c(n),a constant depending only on n,and we will survey partial results(up to date)on the c(n)-cyclic conjecture. 展开更多
关键词 positive sectional curvature conjecture on almost cyclic fundamental groups equivariant Gromov-Hausdorff convergence Alexandrov geometry
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The Incorporation of Human Rights Clauses into the Constitution and the Innovation of Fundamental Rights Hermeneutics
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作者 LI Haiping XING Tao 《The Journal of Human Rights》 2025年第3期663-690,共28页
The incorporation of human rights clauses into the constitution has propelled the innovation of fundamental rights hermeneutics in terms of the subjects of the legal relationships of fundamental rights,the nature of f... The incorporation of human rights clauses into the constitution has propelled the innovation of fundamental rights hermeneutics in terms of the subjects of the legal relationships of fundamental rights,the nature of fundamental rights,the forms of state obligations,the scope of fundamental rights,among other aspects.Regarding the subjects of the legal relationships of fundamental rights,human rights clauses have expanded the subjects of fundamental rights from citizens to natural persons.They have also narrowed down the duty-bearing subjects directed by fundamental rights in clauses that do not define duty-bearing subjects from all entities to state public power.Additionally,in fundamental rights clauses that stipulate private entities as duty-bearing subjects,the duty-bearing subjects have been narrowed down from all private entities to social public power entities.In terms of the nature of fundamental rights,human rights clauses have endowed each specific basic right with dual characteristics of the right to respect and the right to protection.Regarding the forms of state obligations,human rights clauses have established the state obligations corresponding to each specific basic right as obligations to respect and to protect.In terms of the scope of fundamental rights,human rights clauses do not have the function of independently justifying unenumerated fundamental rights,but they can assist other clauses in justifying unenumerated fundamental rights,thereby expanding the scope of fundamental rights to a limited extent. 展开更多
关键词 human rights fundamental rights state obligations unenumerated fundamental rights
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Sufficient and Necessary Conditions for Leader-Following Consensus of Second-Order Multi-Agent Systems via Intermittent Sampled Control
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作者 Ziyang Wang Yuanzhen Feng +1 位作者 Zhengxin Wang Cong Zheng 《Computers, Materials & Continua》 2025年第6期4835-4853,共19页
Continuous control protocols are extensively utilized in traditional MASs,in which information needs to be transmitted among agents consecutively,therefore resulting in excessive consumption of limited resources.To de... Continuous control protocols are extensively utilized in traditional MASs,in which information needs to be transmitted among agents consecutively,therefore resulting in excessive consumption of limited resources.To decrease the control cost,based on ISC,several LFC problems are investigated for second-order MASs without and with time delay,respectively.Firstly,an intermittent sampled controller is designed,and a sufficient and necessary condition is derived,under which state errors between the leader and all the followers approach zero asymptotically.Considering that time delay is inevitable,a new protocol is proposed to deal with the time-delay situation.The error system’s stability is analyzed using the Schur stability theorem,and sufficient and necessary conditions for LFC are obtained,which are closely associated with the coupling gain,the system parameters,and the network structure.Furthermore,for the case where the current position and velocity information are not available,a distributed protocol is designed that depends only on the sampled position information.The sufficient and necessary conditions for LFC are also given.The results show that second-order MASs can achieve the LFC if and only if the system parameters satisfy the inequalities proposed in the paper.Finally,the correctness of the obtained results is verified by numerical simulations. 展开更多
关键词 Intermittent sampled control leader-following consensus time delay second-order multi-agent system
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Second-order topological insulator in twisted bilayer graphene with small twist angles
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作者 Fenghua Qi Jie Cao +1 位作者 Xingfei Zhou Guojun Jin 《Chinese Physics B》 2025年第11期484-490,共7页
In recent years,the study of higher-order topological states and their material realizations has become a research frontier in topological condensed matter physics.We demonstrate that twisted bilayer graphene with sma... In recent years,the study of higher-order topological states and their material realizations has become a research frontier in topological condensed matter physics.We demonstrate that twisted bilayer graphene with small twist angles behaves as a second-order topological insulator possessing topological corner charges.Using a tight-binding model,we compute the topological band indices and corner states of finite-sized twisted bilayer graphene flakes.It is found that for any small twist angle,whether commensurate or incommensurate,the gaps both below and above the flat bands are associated with nontrivial topological indices.Our results not only extend the concept of second-order band topology to arbitrary small twist angles but also confirm the existence of corner states at acute-angle corners. 展开更多
关键词 second-order topological insulators twisted bilayer graphene
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Research on the Application of MWorks Simulation Software in Circuit Fundamentals Courses in Vocational Colleges
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作者 Mingyue Ren 《Journal of Electronic Research and Application》 2025年第3期144-151,共8页
This article focuses on the teaching of circuit foundation courses in vocational colleges and explores in depth the application of MWorks simulation software.By analyzing the limitations of traditional circuit foundat... This article focuses on the teaching of circuit foundation courses in vocational colleges and explores in depth the application of MWorks simulation software.By analyzing the limitations of traditional circuit foundation course teaching,this article elaborates on the advantages of MWorks software in teaching,including intuitive presentation of circuit principles,provision of rich component libraries,and powerful analysis functions.Detailed teaching practice cases based on the software were introduced,such as simple circuit construction and analysis,complex circuit fault troubleshooting,etc.,and the application effect was demonstrated by comparing actual teaching data.The results show that MWorks simulation software effectively enhances students’learning interest,practical ability,and theoretical knowledge mastery,providing strong support for the improvement of the teaching quality of circuit foundation courses in vocational colleges. 展开更多
关键词 Vocational colleges Circuit fundamentals course MWorks simulation software Teaching application
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A Study on the Argumentation and Reasoning in Recording and Review Cases:Taking Fundamental Rights Cases as an Example
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作者 QIN Wenfeng JIANG Yu(Translated) 《The Journal of Human Rights》 2025年第5期1208-1232,共25页
Protecting citizens’fundamental rights is one of the basic functions of the system of recording and review,and relevant cases should fully embody this function.However,whether they are recording and review cases conc... Protecting citizens’fundamental rights is one of the basic functions of the system of recording and review,and relevant cases should fully embody this function.However,whether they are recording and review cases concerning fundamental rights or other types of recording and review cases,their argumentative logic is mainly reflected in legislative logic and policy implementation logic,ultimately aiming at the reconstruction of legal norms and featuring the nature of proactive legislation.At the same time,the argumentation of review authorities lacks technicality,with deficiencies in expounding the normative connotations of fundamental rights and social facts,making it impossible to highlight the protection of citizens’fundamental rights in review argumentation.The function of protecting fundamental rights in review argumentation should be reflected in three aspects:the function of transmitting fundamental rights values,the function of providing fundamental rights rules,and the function of taking fundamental rights as a methodology.Centering on these three points,an argumentation model for the recording and review of fundamental rights with human rights protection as the starting point should be constructed. 展开更多
关键词 recording and review fundamental rights rights protection review argumentation
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Electromagnetically induced transparency and second-order sideband effects in a Laguerre–Gaussian cavity optorotational system with Kerr medium
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作者 Jing-Xuan Li Su-Mei Huang Ai-Xi Chen 《Communications in Theoretical Physics》 2025年第7期54-62,共9页
In this paper,we investigate the phenomena of electromagnetically induced transparency and the generation of second-order sideband in a Laguerre–Gaussian cavity optorotational system with a Kerr nonlinear medium.Usin... In this paper,we investigate the phenomena of electromagnetically induced transparency and the generation of second-order sideband in a Laguerre–Gaussian cavity optorotational system with a Kerr nonlinear medium.Using the perturbation method,we analyze the first-and second-order sideband generations in the output field from the system under the actions of a strong control field and a weak probe field.Numerical simulations show that the Kerr nonlinearity can lead to the occurrence of the asymmetric line shape in the transmission of the probe field.Comparing with traditional scheme for generating the second-order sideband,our spectral shape of the second-order sideband is amplified and becomes asymmetric,which has potential applications in precision measurement,high-sensitivity devices,and frequency conversion. 展开更多
关键词 Laguerre–Gaussian cavity optorotational system electromagnetically induced transparency second-order sideband generation Kerr medium
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Stabilization of second-order bilinear systems with time delay by a class of bounded feedbacks
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作者 Khalil El Kazoui Hassan Ezzaki 《Control Theory and Technology》 2025年第4期579-589,共11页
The stabilization problem of second-order bilinear systems with time delay is investigated.Feedback controls are chosen so that the strong and exponential stabilization of the system is ensured.The obtained results ar... The stabilization problem of second-order bilinear systems with time delay is investigated.Feedback controls are chosen so that the strong and exponential stabilization of the system is ensured.The obtained results are illustrated by wave and beam equations with simulation. 展开更多
关键词 second-order systems Bilinear systems Time delay Strong stabilization Exponential stabilization Wave equation Beam equation
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An Efficient GPU Solver for Maximizing Fundamental Eigenfrequency in Large-Scale Three-Dimensional Topology Optimization
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作者 Tianyuan Qi Junpeng Zhao Chunjie Wang 《Computer Modeling in Engineering & Sciences》 2025年第10期127-151,共25页
A major bottleneck in large-scale eigenfrequency topology optimization is the repeated solution of the generalized eigenvalue problem.This work presents an efficient graphics processing unit(GPU)solver for threedimens... A major bottleneck in large-scale eigenfrequency topology optimization is the repeated solution of the generalized eigenvalue problem.This work presents an efficient graphics processing unit(GPU)solver for threedimensional(3D)topology optimization that maximizes the fundamental eigenfrequency.The Successive Iteration of Analysis and Design(SIAD)framework is employed to avoid solving a full eigenproblem at every iteration.The sequential approximation of the eigenpairs is solved by the GPU-accelerated multigrid-preconditioned conjugate gradient(MGPCG)method to efficiently improve the eigenvectors along with the topological evolution.The cluster-mean approach is adopted to address the non-differentiability issue caused by repeated eigenfrequencies.The corresponding sensitivity analysis method is provided.The parallelized gradient-based Zhang-Paulino-Ramos Jr.(ZPR)algorithm is employed to update the design variables.The effectiveness of the proposed solver is demonstrated through two large-scale numerical examples.The first example demonstrates the accuracy,efficiency,and scalability of the proposed solver by solving a 3D optimization problem of 50.33 million elements being solved in approximately 15.2 h over 300 iterations on a single NVIDIA Tesla V100 GPU.The second example validates the effectiveness of the proposed solver in the presence of repeated eigenfrequencies.Our findings also highlight that higher-resolution models produce distinct optimized structures with higher fundamental frequencies,underscoring the necessity of large-scale topology optimization. 展开更多
关键词 Topology optimization large scale fundamental frequency GPU acceleration successive iteration of analysis and design
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Second-Order Transconductance-Mode Universal Filter Based on CCCⅡand OTA
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作者 HOU Jingqiang YE Xiangdong +1 位作者 ZHENG Jie LI Yongan 《Wuhan University Journal of Natural Sciences》 2025年第5期441-446,共6页
This research,based on Mason's formula,proposes a novel design for a second-order transconductance-mode universal filter with the operational transconductance amplifier(OTA)as the core and the second-generation cu... This research,based on Mason's formula,proposes a novel design for a second-order transconductance-mode universal filter with the operational transconductance amplifier(OTA)as the core and the second-generation current-controlled conveyor(CCCⅡ)as the auxiliary.The circuit incorporates two OTAs,one CCCⅡ,two grounded capacitors,and one grounded resistor.The quality factor Q and natural frequency fo of the filter can be electronically tuned and are not sensitive to temperature.The input and output terminals of the cir-cuit exhibit no loading effect,and the sensitivity of the circuit is low.At last,alternating frequency analysis,parameter scanning analysis,and temperature scanning analysis have been carried out by using Multisim software,confirming the correctness and effectiveness of the designed circuit. 展开更多
关键词 second-order universal filter transconductance-mode circuit second-generation current-controlled conveyor(CCCII) operational transconductance amplifier(OTA)
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Upholding Fundamental Principles and Breaking New Ground in Building China’s Independent Human Rights Knowledge System——A Theoretical Review of and Outlook for Human Rights Research in 2024
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作者 WANG Liwan DI Lei CHEN Feng(Translated) 《The Journal of Human Rights》 2025年第2期462-501,共40页
In 2024,China’s human rights research has assumed a distinct“autonomy-oriented shift,”with scholars beginning to refine and construct uniquely Chinese and locally identifiable human rights concepts,categories,and d... In 2024,China’s human rights research has assumed a distinct“autonomy-oriented shift,”with scholars beginning to refine and construct uniquely Chinese and locally identifiable human rights concepts,categories,and discourses.Building an independent human rights knowledge system has become a core academic focus in China’s human rights research field.Upholding fundamental principles and breaking new ground are the key methodological principles for the process.China’s human rights research should be rooted in the“cultural lineage”by preserving the essence of fine traditional Chinese culture,guided by the“moral lineage”by adhering to the Marxist view on human rights,and anchored in the“Four-sphere Confidence”by upholding a distinct human rights development path,so as to define the historical coordinates and value stance of China’s independent human rights knowledge system.Meanwhile,it should maintain a high degree of openness in knowledge,theory,and methodology to address emerging rights demands and contribute to building a new global human rights governance order,so as to underscore the mission of China’s independent human rights knowledge system in the contemporary era and China’s responsibility as a major global actor.China’s human rights research should uphold the dialectical unity between the fundamental principles and innovations,and advance the systemic and theoretical interpretation of its independent human rights knowledge. 展开更多
关键词 China’s independent human rights knowledge system fundamental principles and innovations China’s human rights research China’s human rights development path identifiable human rights concepts in China
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On Some Fundamental Theorems in Stability Theory 被引量:27
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作者 徐道义 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第2期61-67,共7页
This paper gives several fundamental theorems for the stability, uniform stability, asymptotic stability and uniform asymptotic stability. Those theorems allow the derivative of Lyapunov functions to be positive on ce... This paper gives several fundamental theorems for the stability, uniform stability, asymptotic stability and uniform asymptotic stability. Those theorems allow the derivative of Lyapunov functions to be positive on certain sets,relax the restriction about the rate of change of state variable in a system to be bounded in Marachkov's theorem and extend the related results in [4—7]. 展开更多
关键词 STABILITY Lyapunov fundamental theorem nonautonomous differential equations
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Study of macroscopic fundamental diagram on Shanghai urban expressway network in China 被引量:3
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作者 石心怡 林航飞 《Journal of Southeast University(English Edition)》 EI CAS 2016年第1期106-111,共6页
The macroscopic fundamental diagram( MFD) is studied to obtain the aggregate behavior of traffic in cities. This paper investigates the existence and the characteristics of different types of daily MFD for the Shang... The macroscopic fundamental diagram( MFD) is studied to obtain the aggregate behavior of traffic in cities. This paper investigates the existence and the characteristics of different types of daily MFD for the Shanghai urban expressway network. The existence of MFD in the Shanghai urban expressway network is proved based on two weeks' data.Moreover, the hysteresis phenomena is present in most days and the network exhibits different hysteresis loops under different traffic situations. The relationship between the hysteresis phenomena and the inhomogeneity of traffic distribution is verified. The MFDs in the years of 2009 and 2012 are compared. The hysteresis loop still exists in 2012, which further verifies the existence of the hysteresis phenomenon. The direct relationship between the length of the hysteresis loop( ΔO) and the congestion is proved based on sufficient data. The width of the hysteresis loop, i. e., the drop in network flow( ΔQ) has no relationship with the congestion, and it varies from day to day under different traffic situations. 展开更多
关键词 macroscopic fundamental diagram(MFD) hysteresis phenomena urban expressway network index of congestion
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Second-Order Raman Scattering from n- and p-Type 4H-SiC
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作者 高欣 孙国胜 +4 位作者 李晋闽 王雷 赵万顺 张永新 曾一平 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第12期1555-1560,共6页
The results of second-order Raman-scattering experiments on n- and p-type 4H-SiC are presented,covering the acoustic and the optical overtone spectral regions.Some of the observed structures in the spectra are assigne... The results of second-order Raman-scattering experiments on n- and p-type 4H-SiC are presented,covering the acoustic and the optical overtone spectral regions.Some of the observed structures in the spectra are assigned to particular phonon branches and the points in the Brillouin zone from which the scattering originates.There exists a doublet at 626/636cm -1 with energy difference about 10cm -1 in both n- and p-type 4H-SiC,which is similar to the doublet structure with the same energy difference founded in hexagonal GaN,ZnO, and AlN.The cutoff frequency at 1926cm -1 of the second-order Raman is not the overtone of the A 1(LO) peak of the n-type doping 4H-SiC,but that of the undoping one.The second-order Raman spectrum of 4H-SiC can hardly be affected by doping species or doping density. 展开更多
关键词 H-SiC second-order Raman cutoff frequency
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Fast estimation of fundamental matrix based on stripe constraints
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作者 杨安康 刘京南 +1 位作者 内田敬久 内田悦行 《Journal of Southeast University(English Edition)》 EI CAS 2008年第4期473-477,共5页
In order to improve the performance of estimating the fundamental matrix, a key problem arising in stereo vision, a novel method based on stripe constraints is presented. In contrast to traditional methods based on al... In order to improve the performance of estimating the fundamental matrix, a key problem arising in stereo vision, a novel method based on stripe constraints is presented. In contrast to traditional methods based on algebraic least-square algorithms, the proposed approach aims to minimize a cost function that is derived from the minimum radius of the Hough transform. In a structured-light system with a particular stripe code pattern, there are linear constraints that the points with the same code are on the same surface. Using the Hough transform, the pixels with the same code map to the Hough space, and the radius of the intersections can be defined as the evaluation function in the optimization progress. The global optimum solution of the fundamental matrix can be estimated using a Levenberg- Marquardt optimization iterative process based on the Hough transform radius. Results illustrate the validity of this algorithm, and prove that this method can obtain good performance with high efficiency. 展开更多
关键词 fundamental matrix structured-light stripe code pattern stereo vision
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Observation of Fundamental and High Order Raman Modes of β-Carotenes in Pd OECC Thin Film by SERS
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作者 刘玉龙 刘金全 +4 位作者 朱恪 杨国桢 单际修 李良璧 匡廷云 《Acta Botanica Sinica》 CSCD 2000年第12期1231-1234,共4页
Raman spectra of purified oxygen evolution core complexes (Pd OECC) thin films on silver mirror substrates have been taken over the frequency range of 250-3100 cm -1 by surface enhanced Raman scattering (SERS). B... Raman spectra of purified oxygen evolution core complexes (Pd OECC) thin films on silver mirror substrates have been taken over the frequency range of 250-3100 cm -1 by surface enhanced Raman scattering (SERS). Besides the fundamental frequency modes of β_carotene in Pd OECC, many weak peaks are observed. According to the selection rules of overtone and combination bands, most of them are attributed to the second_order Raman spectra of β_carotene. Compared with the SERS of normal Pd OECC, the SERS of Pd OECC after strong illumination shows a decrease in scattering intensity and an increase in line widths, indicating changes of conformation and micro_environment of β_carotene. The results of SERS are consistent with the changes of absorption spectrum of Pd OECC induced by strong illumination. There are no changes that can be ascribed to new vibration bands, so it is deduced that Pd OECC on the silver mirror is identical to that in the solution. In summary, SERS proved a good method to study the photodamage mechanism of photosynthesis. 展开更多
关键词 SERS photosynthesis photodamage Β-CAROTENE fundamental and high order Raman modes
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