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Approximate trace and singleton failures equivalences for transition systems 被引量:2
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作者 Chao Wang Jinzhao Wu Hongyan Tan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第4期886-896,共11页
Established system equivalences for transition systems, such as trace equivalence and failures equivalence, require the ob- servations to be exactly identical. However, an accurate measure- ment is impossible when int... Established system equivalences for transition systems, such as trace equivalence and failures equivalence, require the ob- servations to be exactly identical. However, an accurate measure- ment is impossible when interacting with the physical world, hence exact equivalence is restrictive and not robust. Using Baire met- ric, a generalized framework of transition system approximation is proposed by developing the notions of approximate language equivalence and approximate singleton failures (SF) equivalence. The framework takes the traditional exact equivalence as a special case. The approximate language equivalence is coarser than the approximate Slc equivalence, just like the hierarchy of the exact ones. The main conclusion is that the two approximate equiva- lences satisfy the transitive property, consequently, they can be successively used in transition system approximation. 展开更多
关键词 approximate equivalence TRACE singleton failures(SF) transition systems.
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Approximate Reachability and Bisimulation Equivalences for Transition Systems 被引量:1
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作者 王超 吴尽昭 +1 位作者 谭红艳 付军 《Transactions of Tianjin University》 EI CAS 2016年第1期19-23,共5页
Using Baire metric, this paper proposes a generalized framework of transition system approximation by developing the notions of approximate reachability and approximate bisimulation equivalences. The proposed framewor... Using Baire metric, this paper proposes a generalized framework of transition system approximation by developing the notions of approximate reachability and approximate bisimulation equivalences. The proposed framework captures the traditional exact equivalence as a special case. Approximate reachability equivalence is coarser than approximate bisimulation equivalence, just like the hierarchy of the exact ones. Both approximate equivalences satisfy the transitive property, consequently, they can be used in transition system approximation. 展开更多
关键词 approximate equivalence REACHABILITY BISIMULATION transition system
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CONTROL CHAOS IN TRANSITION SYSTEM USING SAMPLED-DATA FEEDBACK 被引量:1
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作者 陆君安 谢进 +1 位作者 吕金虎 陈士华 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2003年第11期1309-1315,共7页
The method for controlling chaotic transition system was investigated using sampled- data . The output of chaotic transition system was sampled at a given sampling rate , then the sampled output was used by a feedback... The method for controlling chaotic transition system was investigated using sampled- data . The output of chaotic transition system was sampled at a given sampling rate , then the sampled output was used by a feedbacks subsystem to construct a control signal for controlling chaotic transition system to the origin . Numerical simulations are presented to show the effectiveness and feasibility of the developed controller. 展开更多
关键词 sampled-data feedback transition system CONTROL
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Approximate Failures Semantics for Polynomial Labelled Transition Systems 被引量:1
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《Journal of Donghua University(English Edition)》 EI CAS 2013年第6期472-476,共5页
Labelled transition systems(LTSs) are widely used to formally describe system behaviour.The labels of LTS are extended to offer a more satisfactory description of behaviour by refining the abstract labels into multiva... Labelled transition systems(LTSs) are widely used to formally describe system behaviour.The labels of LTS are extended to offer a more satisfactory description of behaviour by refining the abstract labels into multivariate polynomials.These labels can be simplified by numerous numerical approximation methods.Those LTSs that can not apply failures semantics equivalence in description and verification may have a chance after using approximation on labels.The technique that combines approximation and failures semantics equivalence effectively alleviates the computational complexity and minimizes LTS. 展开更多
关键词 labelled transition system (LTS) failures semantics numerical approximation
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A Geometric Method for Generating Discrete Trace Transition System of a Polyhedral Invariant Hybrid Automaton
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作者 Sobhi Baniardalani Javad Askari 《Intelligent Control and Automation》 2012年第2期197-206,共10页
Supervisory control and fault diagnosis of hybrid systems need to have complete information about the discrete states transitions of the underling system. From this point of view, the hybrid system should be abstracte... Supervisory control and fault diagnosis of hybrid systems need to have complete information about the discrete states transitions of the underling system. From this point of view, the hybrid system should be abstracted to a Discrete Trace Transition System (DTTS) and represented by a discrete mode transition graph. In this paper an effective method is proposed for generating discrete mode transition graph of a hybrid system. This method can be used for a general class of industrial hybrid plants which are defined by Polyhedral Invariant Hybrid Automata (PIHA). In these automata there are no resetting maps, while invariant sets are defined by linear inequalities. Therefore, based on the continuity property of the state trajectories in a PIHA, the problem is reduced to finding possible transitions between all two adjacent discrete modes. In the presented method, the possibility and the direction of such transitions are detected only by computing the angle between the vector field and the normal vector of the switching surfaces. Thus, unlike the most other reachability methods, there is no need to solve differential equations and to do mapping computations. In addition, the proposed method, with some modifications can be applied for extracting Stochastic or Timed Discrete Trace Transition Systems. 展开更多
关键词 HYBRID system DISCRETE TRACE transition system POLYHEDRAL INVARIANT HYBRID Automata DISCRETE Mode transition Graph
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Unpacking phase transitions in multi-component drug systems:A case study
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作者 Shifang Song Chenyu Wu +3 位作者 Li Zhang Dezhi Yang Yang Lu Zhengzheng Zhou 《Chinese Chemical Letters》 2025年第7期508-512,共5页
The phase transition among different solid forms of active pharmaceutical ingredients can significantly influence their physicochemical properties,potentially leading to clinical safety risks.However,phase transition ... The phase transition among different solid forms of active pharmaceutical ingredients can significantly influence their physicochemical properties,potentially leading to clinical safety risks.However,phase transition mechanisms remain under explored,especially in multi-component drugs.Here we report a novel ciprofloxacin-diclofenac salt system and investigate phase transitions among its anhydrate,dihydrate,and methanol solvate forms.The study focused on the influence of water activity and solvent vapor conditions,elucidating the role of vip molecules in driving these transitions.These findings offer new insights into polymorphic phase transitions,advancing our understanding of stability and performance in pharmaceutical formulations. 展开更多
关键词 Phase transition Water activity Solvent vapor CIPROFLOXACIN DICLOFENAC
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Sustainable transition for cereal-based agri-food systems in China:Prospective advantages of whole-grain adoption
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作者 Yilin Zhao Yaxuan Wang +3 位作者 Xueqin Zhu Bin Tan Xun Wei Xiangyuan Wan 《The Crop Journal》 2025年第5期1322-1332,共11页
A dietary transition from refined to whole grains would optimize grain processing,reduce food loss and emissions,and increase food nutritional contents.The results of systematical analysis and calculations in our stud... A dietary transition from refined to whole grains would optimize grain processing,reduce food loss and emissions,and increase food nutritional contents.The results of systematical analysis and calculations in our study show that the average processing loss rate of grains including rice,wheat,and maize is approximately 4.1%in China due to the refinement,equivalent to an annual loss of around 13.3 Mt of grains.Furthermore,the refining process significantly reduces the nutritional contents of rice(51.6%),wheat flour(55.4%),and corn products(80.4%)mainly resulting from the removal of dietary fiber,minerals,and vitamins in refined grains.Replacing refined grains with whole grains in diets would lower agricultural carbon emissions by 2.7%,reducing agricultural water use by 4.3%,and saving arable land by 1,972,607 ha.Total environmental footprint could be reduced by 35%to 79%under three proposed scenarios.These findings indicate that shifting toward whole grain-based diets by Chinese consumers could reduce food losses,enhance human health,and improve environmental sustainability.This approach offers a promising strategy for transitioning towards more resilient and sustainable agri-food systems,benefiting human and planetary health. 展开更多
关键词 Agri-Food systems Whole grains Food transition Food security Emission reducti
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Unveiling transition metal dinitrides for high-efficiency information devices through systematic first-principles calculations
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作者 Jun-Fei Ding Qiu-Shi Yao +4 位作者 Yun-Peng Qu Farid Man-shaii Shao-Lei Wang Xiao-Si Qi Yao Liu 《Rare Metals》 2025年第7期4789-4800,共12页
Currently,the development of high-efficiency two-dimensional(2D)transistors is still hindered by the limited availability of suitable semiconductors and the contact resistance between the metal contact and the 2D semi... Currently,the development of high-efficiency two-dimensional(2D)transistors is still hindered by the limited availability of suitable semiconductors and the contact resistance between the metal contact and the 2D semiconductors.Endeavors to address these challenges are highly desired.In this study,we conducted a comprehensive exploration of the potential 2D transition metal dinitrides(TMN_(2)s,TM=all the 3d,4d and 5d transition metals)with hexagonal(h-)and trigonal(t-)phases through systematic first-principles calculations.Among all h-TMN_(2)s and t-TMN_(2)s structures,we identified 8 TMN_(2)s that exhibit dynamical and thermal stability at room temperature.Of these,the h-TiN_(2),h-ZrN_(2)and h-HfN_(2)arefound to be semiconductors,and their direct bang gap,calculated at the HSE06 level,are 1.48,1.96 and 2.64 eV,respectively.The electron and hole mobility(μ_(e)andμ_(h))of these three structures exceed 1×10^(4)and1×10^(3)cm^(2)·V^(-1)·s^(-1),respectively.Especially,theμeof h-TiN_(2)amounts to 2.5×10^(4)cm^(2)·V^(-1)·s^(-1),and theμhof h-ZrN_(2)reaches to 7.7×10^(3)cm^(2)·V^(-1)·s^(-1).Importantly,unlike the MoS_(2)system,h-TMN_(2)forms Ohm contacts with both transition metals(e.g.,Cu)and 2D metals(e.g.,graphene),with tunneling possibilities exceeding 50%in the Cu system.These outstanding intrinsic semiconductor properties and contact characteristics exhibited by h-TMN_(2)highlight the immense potential of transition metal dinitrides in driving the advancement of next-generation information devices.Our findings significantly broaden the range of 2D materials and provide valuable insights for the development of high-eficiency 2D information devices. 展开更多
关键词 Two-dimensional(2D)materials Metal semiconductor contact transition metal dinitrides 2D semiconductors First-principles calculations
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Design and optimization of generation and transportation systems for coherent THz transition radiation in spectroscopic applications
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作者 Siriwan Pakluea Kanlayaporn Kongmali +3 位作者 Monchai Jitvisate Jatuporn Saisut Chitrlada Thongbai Sakhorn Rimjaem 《Nuclear Science and Techniques》 2025年第8期34-48,共15页
Terahertz(THz)radiation possesses unique properties that make it a promising light source for applications in various fields,particularly spectroscopy and imaging.Ongoing research and development in THz technology has... Terahertz(THz)radiation possesses unique properties that make it a promising light source for applications in various fields,particularly spectroscopy and imaging.Ongoing research and development in THz technology has focused on developing or improving THz sources,detectors,and applications.At the PBP-CMU Electron Linac Laboratory(PCELL)of the Plasma and Beam Physics Research Facility in Chiang Mai University,high-intensity THz radiation has been generated in the form of coherent transition radiation(TR)and investigated since 2006 for electron beams with energies ranging from 8 to 12 MeV.In this study,we investigate and optimize the coherent TR arising from short electron bunches with energies ranging from 8 to 22 MeV using an upgraded linear-accelerator system with a higher radio-frequency(RF)power system.This radiation is then transported from the accelerator hall to the experimental room,in which the spectrometers are located.Electron-beam simulations are conducted to achieve short bunch lengths and small transverse beam sizes at the TR station.Radiation properties,including the radiation spectrum,angular distribution,and radiation polarization,are thoroughly investigated.The electron-bunch length is evaluated using the measuring system.The radiation-transport line is designed to achieve optimal frequency response and high transmission efficiency.A radiation-transmission efficiency of approximately 80-90%can be achieved with this designed system,along with a pulse energy ranging from 0.17 to 0.25μJ.The expected radiation spectral range covers up to 2 THz with a peak power of 0.5-1.25 MW.This coherent,broadband,and intense THz radiation will serve as a light source for THz spectroscopy and THz time-domain spectroscopy applications at the PCELL in the near future. 展开更多
关键词 THz radiation transition radiation Radiation transportation
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Variational Quantum Simulation of Dynamical Quantum Phase Transition in Markovian Open Quantum Systems
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作者 Yukai Guo Jinjian Yu Xing Gao 《Chinese Journal of Chemical Physics》 2025年第4期391-400,I0104,共11页
We investigate dynamical quantum phase transitions(DQPTs)in Marko-vian open quantum systems using a variational quantum simulation(VQS)algorithm based on quantum state diffusion(QSD).This approach reformulates the Lin... We investigate dynamical quantum phase transitions(DQPTs)in Marko-vian open quantum systems using a variational quantum simulation(VQS)algorithm based on quantum state diffusion(QSD).This approach reformulates the Lindblad master equation as an ensemble of pure-state trajectories,enabling efficient simula-tion of dissipative quantum dynam-ics with effectively reduced quantum resources.Focusing on the one-di-mensional transverse-field Ising mod-el(TFIM),we simulate quench dynamics under both local and global Lindblad dissipation.The QSD-VQS algorithm accurately captures the nonanalytic cusps in the Loschmidt rate function,and reveals their modulation by dissipation strength and system size.Notably,DQPTs are gradually suppressed under strong local dissipation,while they persist under strong global dissipation due to collective environmental effects.Benchmarking against exact Lindblad solutions confirms the high accuracy and scalability of our method. 展开更多
关键词 Variational quantum simulation Dynamical quantum phase transition Quan-tum state diffusion Transverse-field Ising model
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Electrospun Nanofibrous Transition Metal-based Bifunctional Electrocatalysts Toward Overall Water Splitting
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作者 YIN Yongting LU Xiaofeng 《高等学校化学学报》 北大核心 2026年第1期87-107,共21页
Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen e... Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen evolution reaction(HER)and the anodic oxygen evolution reaction(OER).Transition metal-based catalysts have garnered significant research interest as promising alternatives to noble-metal catalysts,owing to their low cost,tunable composition,and noble-metal-like catalytic activity.Nevertheless,systematic reviews on their application as bifunctional catalysts for overall water splitting(OWS)are still limited.This review comprehensively outlines the principal categories of bifunctional transition metal electrocatalysts derived from electrospun nanofibers(NFs),including metals,oxides,phosphides,sulfides,and carbides.Key strategies for enhancing their catalytic performance are systematically summarized,such as heterointerface engineering,heteroatom doping,metal-nonmetal-metal bridging architectures,and single-atom site design.Finally,current challenges and future research directions are discussed,aiming to provide insightful perspectives for the rational design of high-performance electrocatalysts for OWS. 展开更多
关键词 Electrospinning Nanofibers transition metal-based catalyst Overall water splitting Performance optimization
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Tracking a High-Tech Transition--How technology is powering Guangdong’s manufacturing transformation
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作者 HU FAN 《ChinAfrica》 2026年第1期30-32,共3页
The moment a media delegation from the Republic of the Congo arrived at the Othello Kitchenware Museum on 18 November 2025,they were greeted with a vivid show of Guangdong’s industrial strength.Standing before them w... The moment a media delegation from the Republic of the Congo arrived at the Othello Kitchenware Museum on 18 November 2025,they were greeted with a vivid show of Guangdong’s industrial strength.Standing before them was not a typical exhibition hall,but a building shaped like a gleaming stainless-steel cooking pot. 展开更多
关键词 othello kitchenware museum TECHNOLOGY industrial strength high tech transition guangdong manufacturing transformation
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Paeonol suppresses epithelial-mesenchymal transitiondriven posterior capsular opacification through activation of AMPK signaling
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作者 Qing Wang Qing-Yu Li +6 位作者 Jing Yang Jun Ma Ji-Hua Ping Zheng Wang Dai-Jie Wang Xia Hua Xiao-Yong Yuan 《International Journal of Ophthalmology(English edition)》 2026年第2期219-229,共11页
AIM:To determine whether paeonol(Pae),a naturally occurring phenolic compound,can serve as an effective pharmacological inhibitor of posterior capsular opacification(PCO).METHODS:A rat model of cataract surgery—induc... AIM:To determine whether paeonol(Pae),a naturally occurring phenolic compound,can serve as an effective pharmacological inhibitor of posterior capsular opacification(PCO).METHODS:A rat model of cataract surgery—induced PCO was established,and Pae was administered via anterior chamber injection to evaluate its preventive effect on capsular opacification and fibrotic remodeling.Histological and immunohistochemical analyses were performed to assess epithelial-mesenchymal transition(EMT)—related changes in lens epithelial cells(LECs).Ex vivo lens capsule cultures were employed to examine the expression of Vimentin and Zonula Occludens-1(ZO-1)by immunofluorescence and immunohistochemistry.In the human LEC line SRA01/04,EMT marker expression at both mRNA and protein levels was analyzed following transforming growth factor beta 2(TGF-β2)stimulation,with Pae treatment.Western blotting and immunofluorescence were used to investigate the effect of Pae on TGF-β/Smad signaling and AMP-activated protein kinase(AMPK)activation.Molecular docking was performed to predict Pae–AMPK binding,and rescue experiments with AMPK inhibition were conducted to validate the mechanistic pathway.RESULTS:Pae significantly reduced capsular opacification and fibrotic remodeling in the rat PCO model compared with controls.In LECs,Pae markedly suppressed TGF-β2–induced EMT,evidenced by decreased expression of mesenchymal markers,such as Vimentin,Fibronectin,Collagen 1A1,α-SMA and preserved epithelial junctional protein ZO-1.Mechanistically,Pae was predicted to directly interact with the catalytic pocket of AMPK,which was experimentally confirmed by enhanced AMPK phosphorylation and nuclear translocation(P<0.05).This activation disrupted canonical TGF-β/Smad signaling,leading to suppression of EMT.Rescue experiments using AMPK inhibition abrogated the anti-EMT effect of Pae,further validating the AMPK-dependent mechanism.CONCLUSION:Pae exerts a potent inhibitory effect on PCO formation by blocking EMT of LECs through direct activation of AMPK and subsequent disruption of TGF-β/Smad signaling. 展开更多
关键词 posterior capsular opacification PAEONOL epithelial-mesenchymal transition AMP-activated protein kinase transforming growth factor beta
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Anticipatory management for sustainable cultivated land transitions:Aligning multifunctional trajectories with adaptive zoning guidance
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作者 WU Junjie WANG Lingzhi +3 位作者 LONG Hualou LI Xinyao GUO Wenhua OMRANI Hichem 《Journal of Geographical Sciences》 2026年第1期16-44,共29页
Rapid regional population shifts and spatial polarization have heightened pressure on cultivated land—a critical resource demanding urgent attention amid ongoing urban-rural transition.This study selects Jiangsu prov... Rapid regional population shifts and spatial polarization have heightened pressure on cultivated land—a critical resource demanding urgent attention amid ongoing urban-rural transition.This study selects Jiangsu province,a national leader in both economic and agricultural development,as a case area to construct a multidimensional framework for assessing the recessive morphological characteristics of multifunctional cultivated land use.We examine temporal dynamics,spatial heterogeneity,and propose an integrated zoning strategy based on empirical analysis.The results reveal that:(1)The recessive morphology index shows a consistent upward trend,with structural breaks in 2007 and 2013,and a spatial shift from“higher in the east and lower in the west”to“higher in the south and lower in the north.”(2)Coordination among sub-dimensions of the index has steadily improved.(3)The index is expected to continue rising in the next decade,though at a slower pace.(4)To promote coordinated multidimensional land-use development,we recommend a policy framework that reinforces existing strengths,addresses weaknesses,and adapts zoning schemes to current spatial conditions.This research offers new insights into multifunctional cultivated land systems and underscores their role in enhancing human well-being,securing food supply,and supporting sustainable urban-rural integration. 展开更多
关键词 multifunctional cultivated land use recessive transition economic-social-ecological sub-dimension zoning management sustainable agro-urban systems future prediction Jiangsu province
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Systematic review of the old and new concepts in the epithelial-mesenchymal transition of colorectal cancer 被引量:11
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作者 Simona Gurzu Camelia Silveanu +3 位作者 Annamaria Fetyko Vlad Butiurca Zsolt Kovacs Ioan Jung 《World Journal of Gastroenterology》 SCIE CAS 2016年第30期6764-6775,共12页
Epithelial-to-mesenchymal transition(EMT) is defined as the transformation of an epithelial cell into a spindle cell with the loss of membrane E-cadherin expression and the gain of mesenchymal markers positivity. In t... Epithelial-to-mesenchymal transition(EMT) is defined as the transformation of an epithelial cell into a spindle cell with the loss of membrane E-cadherin expression and the gain of mesenchymal markers positivity. In the field of colorectal cancer(CRC), first data about EMT was published in 1995 and more than 400 papers had been written up to March 2016. Most of them are focused on the molecular pathways and experimentally-proved chemoresistance. In the present article, an update in the field of EMT in CRC based on the review of the literature and personal experience of the authors is presented. The information about the molecular and immunohistochemical(IHC) particularities of these processes and their possible role in the prognosis of CRC were also up-dated. This article focuses on the IHC quantification of the EMT, the immunoprofile of tumor buds and on the relation between EMT, angiogenesis, and stem cells activation. The EMT-induced chemoresistance vs chemotherapyor radiotherapy-induced EMT and cellular senescence was also synthesized for both conventional and targeted therapy. As a future perspective, the EMTangiogenesis-stemness link could be used as a possible valuable parameter for clinical follow-up and targeted therapeutic oncologic management of patients with CRC. Association of dexamethasone and angiotensin converting enzyme inhibitors combined with conventional chemotherapies could have clinical benefits in patients with CRC. The main conclusion is that, although many studies have been published, the EMT features are still incompletely elucidated and newly discovered EMT markers provide confusing data in understanding this complicated process, which might have significant clinical impact. 展开更多
关键词 ANGIOGENESIS COLORECTAL cancer BUDDING Epithelial-mesenchymal transition CHEMORESISTANCE
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Nonlinear Feature of the Abrupt Transitions between Multiple Equilibria States of an Ecosystem Model 被引量:9
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作者 孙国栋 穆穆 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2009年第2期293-304,共12页
Based on a five-variable theoretical ecosystem model, the stability of equilibrium state and the nonlinear feature of the transition between a grassland state and a desert state are investigated. The approach of the c... Based on a five-variable theoretical ecosystem model, the stability of equilibrium state and the nonlinear feature of the transition between a grassland state and a desert state are investigated. The approach of the conditional nonlinear optimal perturbations (CNOPs), which are the nonlinear generalization of the linear singular vectors (LSVs), is adopted. The numerical results indicate that the linearly stable grassland and desert states are nonlinearly unstable to large enough initial perturbations on the condition that the moisture index # satisfies 0.3126 〈 μ 〈 0.3504. The perturbations represent some kind of anthropogenic influence and natural factors. The results obtained by CNOPs, LSVs and Lyapunov vectors (LVs) are compared to analyze the nonlinear feature of the transition between the grassland state and the desert state. Besides this, it is shown that the five-variable model is superior to the three-variable model in providing more visible signals when the transitions occur. 展开更多
关键词 nonlinear feature abrupt transition grassland and desert ecosystem shading effect
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Metallogenic Effect of Transition of Tectonic Dynamic System 被引量:15
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作者 DengJun WangQingfei +3 位作者 WeiYanguang WangJianping SunZhongshi YangLiqiang 《Journal of China University of Geosciences》 SCIE CSCD 2004年第1期23-28,共6页
Tectonic dynamic system transition, one of the main factors in metallogenesis, controls metallogenic fluid movement and ore body location in orefields and on an ore deposit scale (mainly in the continental tectonic se... Tectonic dynamic system transition, one of the main factors in metallogenesis, controls metallogenic fluid movement and ore body location in orefields and on an ore deposit scale (mainly in the continental tectonic setting), and even the formation and distribution of large-scale deposit clusters. Tectonic dynamic system transition can be classified as the spacious difference of the tectonic dynamic system in various geological units and the temporal alteration of different tectonic dynamic systems. The former results in outburst of mineralization, while the latter leads to the metallogenic diversity. Both of them are the main contents of metallogenic effect of tectonic dynamic system transition, that is, the alteration of dynamic system, the occurrence of mineralization, and the difference of regional tectonic dynamic system and metallogenic diversity. Generally speaking, the coupling of spatial difference of tectonic dynamic system and its successive alternation controlled the tempo-spatial evolution regularity of mineralization on a larger scale. In addition, the analysis of mineralization factors and processes of typical ore deposits proved that the changes of tectonic stress field, the direct appearance of tectonic dynamic system transition, may lead to the accident of mineralization physical-chemical field and the corresponding accidental interfaces were always located at ore bodies. 展开更多
关键词 tectonic dynamic system transition metallogenic diversity interface mineralization.
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Traditional agroecosystem transition in mountainous area of Three Gorges Reservoir Area 被引量:7
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作者 LIANG Xinyuan LI Yangbing +1 位作者 SHAO Jing’an RAN Caihong 《Journal of Geographical Sciences》 SCIE CSCD 2020年第2期281-296,共16页
The Three Gorges Reservoir Area(TGRA)is typical of an ecologically vulnerable area,comprised of rural and mountainous areas,and with high immigration.Because of its economic and ecologic importance,studying the tradit... The Three Gorges Reservoir Area(TGRA)is typical of an ecologically vulnerable area,comprised of rural and mountainous areas,and with high immigration.Because of its economic and ecologic importance,studying the traditional agroecosystem changes in the TGRA is key to rural development and revitalization.In this study,we apply a framework of theoretical analysis,empirical study,and trend prediction to the Caotangxi River watershed within the TGRA.Using QuickBird high-resolution remote sensing images from 2012 to 2017 to evaluate natural resources and farmers’behavior,we analyze the transition and trends in the traditional agroecosystem in mountainous areas of the TGRA at spatial scale of the man-land relationship.We find that the agroecosystem in the TGRA can be divided into four modes using 100 m interval buffer rings:high-low-low,high-low-high,low-high-low and low-low-high mode where the different modes represent the agricultural development stages in the TGRA.Furthermore,the traditional agroecosystem in TGRA,represented by system elements such as farmers and sloping farmland,is transforming to accommodate the diversification of farmer livelihoods.For example,sloping farmland,which was dominated by a production function,now has equal emphasis on ecological and economic functions.Spatially,the range of the agroecosystem transition has migrated beyond high mountain areas to flat valley areas.Generally,this study provides an overview of land use in rural areas,controls on soil and water loss in mountainous areas,and better rural living environments in the TGRA. 展开更多
关键词 Three Gorges Reservoir Area ecologically fragile area mountainous area traditional agroecosystem transition empirical study spatial scale
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A new thermodynamically stable Nb_(2)Ni intermetallic compound phase revealed by peritectoid transition within binary Nb-Ni alloy system 被引量:6
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作者 J.F.Zhao H.P.Wang B.Wei 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第5期246-253,共8页
A new intermetallic compound of thermodynamically stable Nb_(2)Ni phase is discovered within Nb-Ni binary system,refreshing the current situation that there are only three stable intermediate phases of Nb_(7)Ni_(6),Nb... A new intermetallic compound of thermodynamically stable Nb_(2)Ni phase is discovered within Nb-Ni binary system,refreshing the current situation that there are only three stable intermediate phases of Nb_(7)Ni_(6),NbNi_(3) and NbNi_(8).The new stable phase is generated from the peritectoid transition:(Nb)+Nb_(7)Ni_(6)→Nb_(2)Ni,and the transformation temperature is 1533 K.This refreshes the current equilibrium Nb-Ni binary phase diagram.It is confirmed by transmission electron microscopy and the annealing experiments,which is determined to be the FCC structure(Pearson:cF96,space grope:Fd-3m O2,a=11.888A).Furthermore,the equilibrium properties of Nb_(2)Ni phase are produced by density functional theory,including the formation energy,cohesive energy,bulk modulus and lattice constant. 展开更多
关键词 Intermetallic compound Peritectoid transition Transmission electron microscopy Density functional theory Nb alloy
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GRAFT COPOLYMERIZATION OF VINYL MONOMERS ONTO STARCH INITIATED BY TRANSITION METAL-THIOUREA REDOX SYSTEMS 被引量:5
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作者 高建平 田汝川 张黎明 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1996年第2期163-171,共9页
In this paper, the capabilities of grafting acrylonitrile (AN) onto starch initiated by Fe(III)-TU, V(V)-TU, Cr(VI)-TU, Mn(VII)-TU redox systems were compared in the presence of sulfuric acid of different concentratio... In this paper, the capabilities of grafting acrylonitrile (AN) onto starch initiated by Fe(III)-TU, V(V)-TU, Cr(VI)-TU, Mn(VII)-TU redox systems were compared in the presence of sulfuric acid of different concentrations. It was shown that the grafting capability of Mn(VII)-TU is the highest in these initiating systems. Using Mn (VII-TU as initiator, the effects of various acids (HClO4, H2SO4, HNO3, HCl) on the graft copolymerization of acrylonitrile onto starch were discussed, and the capabilities of graft copolymerization of methyl methacrylate (MMA), acrylamide (AM), acrylic acid (AA) onto starch were investigated. The experimental results show that the order of the influences of different acids is HClO4 > H2SO4 > HNO3 > HCl, and the order of grafting capabilities of different monomers grafted onto starch is MMA > AN > AM > AA. The structure and morphology of graft, copolymers were studied with infrared spectroscopy and scanning electron microscopy. The size, shape and roughness of surface of the grafted starch granules are changed after grafting. 展开更多
关键词 transition metal THIOUREA graft copolymerization STARCH
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