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Exact solutions for the transcritical Riemann problem of two-parameter fluids
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作者 Haotong BAI Yixin YANG +2 位作者 Wenjia XIE Dejian LI Mingbo SUN 《Applied Mathematics and Mechanics(English Edition)》 2025年第12期2385-2406,共22页
Transcritical and supercritical fluids widely exist in aerospace propulsion systems,such as the coolant flow in the regenerative cooling channels of scramjet engines.To numerically simulate the coolant flow,we must ad... Transcritical and supercritical fluids widely exist in aerospace propulsion systems,such as the coolant flow in the regenerative cooling channels of scramjet engines.To numerically simulate the coolant flow,we must address the challenges in solving Riemann problems(RPs)for real fluids under complex flow conditions.In this study,an exact numerical solution for the one-dimensional RP of two-parameter fluids is developed.Due to the comprehensive resolution of fluid thermodynamics,the proposed solution framework is suitable for all forms of the two-parameter equation of state(EoS).The pressure splitting method is introduced to enable parallel calculation of RPs across multiple grid points.Theoretical analysis demonstrates the isentropic nature of weak waves in two-parameter fluids,ensuring that the same mathematical properties as ideal gas could be applied in Newton's iteration.A series of numerical cases validate the effectiveness of the proposed method.A comparative analysis is conducted on the exact Riemann solutions for the real fluid EoS,the ideal gas EoS,and the improved ideal gas EoS under supercritical and transcritical conditions.The results indicate that the improved one produces smaller errors in the calculation of momentum and energy fluxes. 展开更多
关键词 two-parameter fluid Riemann problem(RP) exact solution supercritical fluid pressure splitting transcritical fluid
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Empathetic Response Generation Based on Topic Shifting
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作者 Lili Yin Xiaoqiang Du Hengwen Gu 《Journal of Harbin Institute of Technology(New Series)》 2025年第5期65-73,共9页
The current dialogue system can be sensitive to the emotions in the user's words,generating an empathetic response to help calm the user's emotions.But in some cases,eliciting empathetic responses may not adeq... The current dialogue system can be sensitive to the emotions in the user's words,generating an empathetic response to help calm the user's emotions.But in some cases,eliciting empathetic responses may not adequately mitigate the adverse effects that the current conversation topic is having on users.The dialogue system will continue the conversation with the user under this uncomfortable topic,which will lead to a worse chat situation or even an impasse.To solve this problem,a dialogue system that can change the topic autonomously according to the user's emotions is proposed in this paper.Specifically,the dialogue system first collects the emotional semantic information of the users and then detects it according to the emotion classification module.Once the detection results show that the user is in a bad mood,the topic change module selects a new topic from the context to shift to and generates a response.This not only helps to calm the user's mood but also move the conversation to a new area,steering the user away from the uncomfortable topic.The experimental results show that the proposed method incurs less cost in terms of content quality,but improves the emotional perception ability.Additionally,it endows the dialogue system with the ability to change the topic,and improves the user's dialogue experience. 展开更多
关键词 topic shifting empathetic response emotion classification
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Efficient Model Reduction of Linear Time-varying Systems via Shifted Legendre Polynomial Approximations
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作者 XIAO Zhihua TANG Man ZHU Zhihui 《应用数学》 北大核心 2026年第2期481-493,共13页
This paper presents an efficient model reduction technique for linear time-varying systems based on shifted Legendre polynomials.The approach constructs approximate low-rank decomposition factors of finite-time Gramia... This paper presents an efficient model reduction technique for linear time-varying systems based on shifted Legendre polynomials.The approach constructs approximate low-rank decomposition factors of finite-time Gramians directly from the expansion coefficients of impulse responses.Leveraging these factors,we develop two model reduction algorithms that integrate the low-rank square root method with dominant subspace projection.Our method is computationally efficient and flexible,requiring only a few matrix-vector operations and a singular value decomposition of a low-dimensional matrix,thereby avoiding the need to solve differential Lyapunov equations.Numerical experiments confirm the effectiveness of the proposed approach. 展开更多
关键词 Model reduction Time-varying systems Low-rank Gramians Balanced truncation shifted Legendre polynomials
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Research on the Impact of Conception Vessel Dredging Therapy Based on the Theory of Shifting Essence and Changing Qi in Inner Canon of Huangdi on Physical and Mental Health
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作者 Yizhou Shen Fengrun Liu 《Journal of Clinical and Nursing Research》 2025年第5期152-158,共7页
This study,based on the theory of shifting essence and changing Qi in Inner Canon of Huangdi,deeply explores the theoretical basis,operation method of Conception Vessel Dredging Therapy and its influence on human heal... This study,based on the theory of shifting essence and changing Qi in Inner Canon of Huangdi,deeply explores the theoretical basis,operation method of Conception Vessel Dredging Therapy and its influence on human health.Through case analysis and the statistical analysis of medical records during the pandemic,it reveals the remarkable effects of this method in regulating the endocrine system,improving metabolism,and relieving physical and mental diseases.It provides a theoretical and practical basis for the application of traditional Chinese medicine anti-aging therapy in the modern health field,and helps to explore new ways to delay aging and improve physical and mental health. 展开更多
关键词 shifting essence and changing Qi Conception vessel dredging therapy Inner canon of Huangdi Endocrine regulation Metabolic improvement Anti-aging Mental health
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Key Technologies for AI-Driven Network Traffic Classification Workflow and Data Distribution Shift
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作者 Zhao Jianchao Geng Zhaosen +1 位作者 Li Zeyi Wang Pan 《ZTE Communications》 2026年第1期34-44,共11页
With the evolution of next-generation network technologies,the complexity of network management has significantly increased,and the means of network attacks are diversified,bringing new challenges to network traffic c... With the evolution of next-generation network technologies,the complexity of network management has significantly increased,and the means of network attacks are diversified,bringing new challenges to network traffic classification.This paper presents a general AIdriven network traffic classification workflow and elaborates on a traffic data and feature engineering framework.Most importantly,it analyzes the concept and causes of data distribution shifts in ne twork traffic,proposing detection methods and countermeasures.Experimental results on real traffic collected at different time intervals show that application evolution can induce data distribution shifts,which in turn lead to a noticeable degradation in traffic classification performance.Comparative drift detection experiments further confirm that such shifts are more evident over long-term intervals,while short-term traffic remains relatively stable.These findings demonstrate the necessity of incorporating drift-aware mechanisms into AI-driven network traffic classification systems. 展开更多
关键词 traffic classification traffic identification deep learning data distribution shift concept shifting
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Decadal shift in Northeast China’s precipitation around 2000
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作者 Yawen Liao Tianbao Zhao +1 位作者 Jingpeng Zhang Yankun Sun 《Atmospheric and Oceanic Science Letters》 2026年第1期14-21,共8页
Northeast China(NEC),a critical agricultural and ecological zone,has experienced intensified hydrological variability under global warming,with cascading impacts on food security and ecosystem resilience.This study ut... Northeast China(NEC),a critical agricultural and ecological zone,has experienced intensified hydrological variability under global warming,with cascading impacts on food security and ecosystem resilience.This study utilized observational data and two new generation reanalysis products(i.e.,the fifth major global reanalysis produced by ECMWF(ERA5)and the Japanese Reanalysis for Three Quarters of a Century(JRA-3Q))to investigate the shift changes in precipitation in NEC around 2000 and associated water vapor transport.The analysis identified a pivotal interdecadal shift in 1998/99,transitioning from moderate increases(17.5 mm/10 yr during 1980-1998)to accelerated but more variable precipitation growth(85.4 mm/10 yr post-1999).While the mean precipitation during the post-shift period decreased,enhanced anticyclonic circulation amplified moisture divergence over continental NEC,redirecting vapor flux toward coastal regions.Crucially,trajectory analysis demonstrated regime-dependent moisture sourcing:midlatitude westerlies dominated during wet extremes(44% of trajectories in 1998),whereas East Asian monsoon flows prevailed in drought years(36% of trajectories in 2007).The post-1998 period exhibited increased reliance on localized recycling(45%of mid-tropospheric trajectories),reflecting weakened monsoonal inflow.These findings highlight NEC’s growing vulnerability to competing moisture pathways and atmospheric blocking-a dual mechanism that explains rising extremes despite declining mean precipitation.By reconciling dataset discrepancies(ERA5 vs.JRA-3Q trends)and elucidating circulation-precipitation linkages,this work provides actionable insights for climate-resilient agriculture in NEC’s water-stressed ecosystems. 展开更多
关键词 PRECIPITATION Decadal shift Water vapor transport Northeast China
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Survey Analysis of Traditional Chinese Medicine Constitution Among Night Shift Nurses in a Public Grade A Tertiary Hospital
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作者 Ting Li Jia Jiang Wendan Sun 《Journal of Clinical and Nursing Research》 2026年第2期115-121,共7页
Objective:To investigate the distribution of Traditional Chinese Medicine(TCM)constitution among night-shift nurses at a public tertiary-level Class A hospital,thereby identifying new approaches for developing effecti... Objective:To investigate the distribution of Traditional Chinese Medicine(TCM)constitution among night-shift nurses at a public tertiary-level Class A hospital,thereby identifying new approaches for developing effective interventions to enhance their health status.Methods:A total of 601 nurses employed at a public tertiary-level Class A hospital from August 2024 to August 2025 participated in the survey.Analysis was conducted using the Traditional Chinese Medicine Constitution Questionnaire.Results:The most prevalent TCM constitution types among night-shift nurses were Yang Deficiency Constitution(50.4%),Yin Deficiency Constitution(49.8%),Qi Deficiency Constitution(45.4%),and Phlegm-Dampness Constitution(45.1%).Conclusion:A high proportion of clinical night-shift nursing staff exhibit imbalanced constitution types,severely impacting their physical and mental health.Nursing administrators should implement targeted TCM constitution-based health maintenance and regulation to improve the health status of nursing personnel. 展开更多
关键词 Night shift Nurses TCM constitution identification
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Predicting the impacts of climate change on the distribution of rare Meconopsis species in China:Habitat shifts and conservation implications
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作者 Siteng Jiang Renwu Wu +4 位作者 Min Wu Jiachen Liu Hai Yan Wenbin Nie Zhiyi Bao 《Ecological Frontiers》 2026年第1期82-107,共26页
As global climate change intensifies,alpine plants are facing dual pressures of habitat loss and rapid environmental degradation.As one of the world's most biodiverse countries,China's potential shifts in alpi... As global climate change intensifies,alpine plants are facing dual pressures of habitat loss and rapid environmental degradation.As one of the world's most biodiverse countries,China's potential shifts in alpine plant distribution and their profound impact on fragile ecosystems have become a focus of ecological research and conservation efforts,with increasing urgency.Meconopsis,a typical representative of Chinese alpine plants,exhibits diverse adaptability,making it an ideal model for studying how alpine species respond to extreme environmental changes.A lack of comprehensive genus-level analyses may hinder the development of long-term conservation and management strategies.Given the genus's ecological importance,vulnerability,and the risk of trait homogenization in genus-level modeling,there is an urgent need to assess its future distribution patterns,migration trends,and adaptive mechanisms based on habitat classification.In this study,we employed the Maxent model,integrating multidimensional environmental variables,to develop genus-level models and representative habitat-based models(forest,meadows,and periglacial).Results indicate a northwestward expansion and southeastward contraction of suitable habitats under future climate scenarios,with migration patterns in latitude and elevation showing stage-specific characteristics.Key environmental factors varied across models but were mostly associated with seasonal growth traits and microhabitat conditions,highlighting both the universal ecological requirements and niche differentiation within Meconopsis.Based on these findings,we propose a dynamic conservation strategy framework informed by stage-specific responses and habitat differences.Future efforts should focus on incorporating alpine-specific environmental variables and optimizing specimen collection strategies to enhance model performance and support landscape planning and biodiversity conservation. 展开更多
关键词 Alpine plants Climate change Habitat shift Meconopsis Species distribution
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Towards a universal ansatz for heat-induced emission peak shifts:insights from M_(2)SiO_(4):Eu^(2+)(M=Sr,Ba,Ca)phosphors
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作者 Shijie Chen Zul Qarnain +4 位作者 Xiyue Cheng Zhian Li Guoliang Liu Zhuoling Jiang Shuiquan Deng 《Materials Futures》 2026年第2期194-208,共15页
Heat-induced emission peak shift(HIEPS),encompassing both redshift and blueshift,remains mechanistically unresolved in phosphor materials.Using state-of-the-art first-principles calculations of M_(2)SiO_(4):Eu^(2+)(M=... Heat-induced emission peak shift(HIEPS),encompassing both redshift and blueshift,remains mechanistically unresolved in phosphor materials.Using state-of-the-art first-principles calculations of M_(2)SiO_(4):Eu^(2+)(M=Sr,Ba,Ca),we reveal that conventional thermal expansion theory cannot adequately explain these phenomena.Instead,our frozen phonon analysis identifies local electron-phonon coupling as the dominant mechanism,where anisotropic thermal vibrations selectively distort the asymmetric Eu-5d potential well that arises from the dopant’s coordination environment.This distortion manifests through the temperature-sensitiveΔ_(f−d) parameter governing the 5d→4f transition energy,directly controlling spectral shifts.Our findings establish a universal framework for HIEPS in rare-earth phosphors and enable a Δ_(f−d)-guided strategy for designing thermally stable phosphors. 展开更多
关键词 electron-phonon coupling PHOSPHORS first-principles calculations frozen phonon heat-induced emission peak shift
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From Index Evaluation to Intelligent Sensing:Paradigm Shift in Research on Tourism Climate Comfort and Prospects under Technological Enabling
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作者 Xiao WANG 《Meteorological and Environmental Research》 2026年第1期29-31,共3页
Research on tourism climate comfort is undergoing a paradigm shift from classic static assessment to intelligent dynamic sensing.Early models(such as temperature-humidity index and tourism climate index)established ba... Research on tourism climate comfort is undergoing a paradigm shift from classic static assessment to intelligent dynamic sensing.Early models(such as temperature-humidity index and tourism climate index)established based on data of meteorological stations laid the foundation for the discipline but were unable to meet the dynamic demands of climate change,spatial heterogeneity,and individual experience.Global climate change is reshaping the landscape of tourism comfort and driving the assessment to shift towards future risk prediction.Downscaling technology becomes the key to connecting global scenarios and local assessments.Remote sensing and Internet of Things technologies have constructed a"sky-ground"collaborative sensing network,achieving a revolution in data acquisition.Artificial intelligence and big data analysis serve as the intelligent core to drive research from description to prediction.The new paradigm has significant potential in improving assessment accuracy and timeliness,but also faces challenges such as data integration,model interpretability,interdisciplinary integration,and ethical privacy.In the future,it is needed to develop interpretable AI,construct climate digital twins,and promote full-chain coupling research.This transformation is not merely an upgrade of methods,but a fundamental shift in the study of philosophy from an"environment-centered"perspective to an"experience-centered"one,providing key scientific support for sustainable tourism. 展开更多
关键词 Tourism climate comfort Paradigm shift Climate change Remote sensing Internet of Things Artificial intelligence
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Prolonged Sleep Deprivation Induces Cochlear Synaptopathy and Temporary Threshold Shift via the TLR4/NF-κB/NLRP3 Signaling Pathway
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作者 Xiaoqiong Song Kefeng Ma +6 位作者 Mengzhu Cheng Cui Gu Fenghan Wang Xinyu Dai Chunping Wang Xiaojun She Bo Cui 《Biomedical and Environmental Sciences》 2026年第3期368-374,共7页
Sleep is a biological phenomenon with highly conserved evolutionary characteristics.The American Academy of Sleep Medicine and the Sleep Research Society recommend that adults get at least 7 hours of sleep per night[1... Sleep is a biological phenomenon with highly conserved evolutionary characteristics.The American Academy of Sleep Medicine and the Sleep Research Society recommend that adults get at least 7 hours of sleep per night[1].However,the stress caused by fast-paced life often leads to sleep deprivation(SD).SD is strongly associated with damage to the auditory system[2,3].Obstructive sleep apnea-hypopnea syndrome(OSAHS)is a common sleep disorder.Clinical observations indicate that some patients with OSAHS experience persistent hearing loss accompanied by tinnitus and other symptoms[4].More than 61.8%of patients with sudden deafness experienced SD[5]. 展开更多
关键词 TLR sleep deprivation temporary threshold shift sleep deprivation sd sd sleep disorderclinical auditory system NF B cochlear synaptopathy
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Three Shifts That Will Redefine Health Systems
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作者 You Wu Haibo Wang Zongjiu Zhang 《Health Care Science》 2026年第1期1-3,共3页
Academic journals,consulting firms,and mainstream media have often published“predictions”about the future develop-ment of medical and health care.These publications often emphasize the potential of cutting-edge scie... Academic journals,consulting firms,and mainstream media have often published“predictions”about the future develop-ment of medical and health care.These publications often emphasize the potential of cutting-edge scientific or technical breakthroughs.Health Care Science looks at the problem from another perspective.We focus on how these changes enter the health system,how they operate in the real world,and how they reshape the organization and governance of medical services.At the beginning of 2026,we envision the following three major shifts that will reshape healthcare. 展开更多
关键词 academic journals health systems health care science mainstream media shiftS cutting edge scientific technical breakthroughs consulting firms
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A Strategic Shift:Two Sessions reaffirm China’s commitment to high-quality development and global opportunities
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作者 HU FAN 《ChinAfrica》 2026年第4期16-17,共2页
At the start of China’s 15th Five-Year Plan period(2026–2030),signals from March’s Two Sessions point to a subtle but notable change in direction.Policymakers are moving beyond an emphasis on headline growth figure... At the start of China’s 15th Five-Year Plan period(2026–2030),signals from March’s Two Sessions point to a subtle but notable change in direction.Policymakers are moving beyond an emphasis on headline growth figures and are instead concentrating on building a more resilient economic foundation in a volatile global environment. 展开更多
关键词 economic resilience strategic shift two sessions building more resilient economic foundation global opportunities volatile global environment th five year plan high quality development
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Performance of bottleneck shifting for remanufacturing system considering returns' quality grading 被引量:2
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作者 郑玉巧 苏春 +1 位作者 曹白雪 施杨梅 《Journal of Southeast University(English Edition)》 EI CAS 2015年第4期516-521,共6页
Aimed at the remanufacturing system, the effect of the uncertainty of returns' quality on bottleneck shifting is investigated. A novel definition of bottleneck station is presented and the probability of a station be... Aimed at the remanufacturing system, the effect of the uncertainty of returns' quality on bottleneck shifting is investigated. A novel definition of bottleneck station is presented and the probability of a station becoming a bottleneck is also given. By calculating the effective output, the effective operation time (EOT) and the ratio of EOT of each station, the system's current bottleneck of effective output time is determined. By calculating the probability coefficient of variation and index of bottleneck shifting, the quantitative performance of bottleneck shifting is obtained. Discrete event simulation and the experiment design method are adopted to simulate the system, in which the proportion of quality grading, repair rates and process routes are considered. The case study shows that the uncertainty of returns' quality greatly increases the probability of bottleneck shifting, and with the increase of the discrete degree of the returns' repair rate, the bottleneck shifting phenomenon is more obvious. Furthermore, bottleneck shifting is closely related to the process route of the dominating returns' quality grade. 展开更多
关键词 bottleneck shifting REMANUFACTURING returns quality grading UNCERTAINTY
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Error-CompensatingFive-SamplePhase-Shifting Algorithm Based on Phase-Shift Error Estimation
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作者 黄文宇 龚建伟 陆际联 《Journal of Beijing Institute of Technology》 EI CAS 2001年第4期337-341,共5页
A new error compensating five sample phase shifting algorithm which is insensitive to phase shift error is proposed to retrieve the phase distribution of a fringe pattern. It includes two steps. First, the linear ... A new error compensating five sample phase shifting algorithm which is insensitive to phase shift error is proposed to retrieve the phase distribution of a fringe pattern. It includes two steps. First, the linear phase shift error is estimated using four sample images. Then, the phase distribution is calculated with error corrected by using the phase shift error estimated in the first step. As the equations of error estimation and phase calculation are simple, this new algorithm is practical as well as effective. Computer simulations were carried out to verify the effectiveness of the algorithm. Results of two other well known error compensating algorithms are also presented, which show the new algorithm is the least sensitive to phase shift error. 展开更多
关键词 phase shifting algorithm phase measuring profilometry optical measurement
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关于α-shifting环,α-sy环和α-sc环 被引量:1
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作者 张玖琳 王尧 任艳丽 《数学理论与应用》 2013年第3期15-21,共7页
本文讨论α-shifting环、α-sy环、α-sc环以及α-rigid环之间的关系.在α-compatible和Cα条件下,分别给出α-shifting环、α-sy环和α-sc环与相关环之间的等价关系,推广Pourtaherian-Rakhimov的一些研究结论.
关键词 α—shifting α—sy环 α—sc环 α—rigid环 α—compatible环
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Prestack migration velocity analysis based on simplified two-parameter moveout equation 被引量:1
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作者 陈海峰 李向阳 +2 位作者 钱忠平 宋建军 赵桂玲 《Applied Geophysics》 SCIE CSCD 2016年第1期135-144,220,221,共12页
Stacking velocity V_(C2),vertical velocity ratio γ_0,effective velocity ratio γ_(eff),and anisotropic parameter x_(eff) are correlated in the PS-converted-wave(PS-wave) anisotropic prestack Kirchhoff time mi... Stacking velocity V_(C2),vertical velocity ratio γ_0,effective velocity ratio γ_(eff),and anisotropic parameter x_(eff) are correlated in the PS-converted-wave(PS-wave) anisotropic prestack Kirchhoff time migration(PKTM) velocity model and are thus difficult to independently determine.We extended the simplified two-parameter(stacking velocity V_(C2) and anisotropic parameter k_(eff)) moveout equation from stacking velocity analysis to PKTM velocity model updating and formed a new four-parameter(stacking velocity V_(C2),vertical velocity ratio γ_0,effective velocity ratio γ_(eff),and anisotropic parameter k_(eff)) PS-wave anisotropic PKTM velocity model updating and process flow based on the simplified twoparameter moveout equation.In the proposed method,first,the PS-wave two-parameter stacking velocity is analyzed to obtain the anisotropic PKTM initial velocity and anisotropic parameters;then,the velocity and anisotropic parameters are corrected by analyzing the residual moveout on common imaging point gathers after prestack time migration.The vertical velocity ratio γ_0 of the prestack time migration velocity model is obtained with an appropriate method utilizing the P- and PS-wave stacked sections after level calibration.The initial effective velocity ratio γ_(eff) is calculated using the Thomsen(1999) equation in combination with the P-wave velocity analysis;ultimately,the final velocity model of the effective velocity ratio γ_(eff) is obtained by percentage scanning migration.This method simplifies the PS-wave parameter estimation in high-quality imaging,reduces the uncertainty of multiparameter estimations,and obtains good imaging results in practice. 展开更多
关键词 PS-converted-wave PKTM velocity updating two-parameter moveout equation migration imaging
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ANALYSIS OF TIPOVER STABILITY FOR NOVEL SHAPE SHIFTING MODULAR ROBOT 被引量:10
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作者 LIU Jinguo WANG Yuechao +1 位作者 MA Shugen LI Bin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2006年第2期181-186,共6页
A novel three-module robot has been introduced. It can change its configuration to adapt to the uneven terrain and to improve its tipover stability. This three-module tracked robot has three kinds of symmetry configur... A novel three-module robot has been introduced. It can change its configuration to adapt to the uneven terrain and to improve its tipover stability. This three-module tracked robot has three kinds of symmetry configuration. They are line type, triangle type, and row type. After the factors and the countermeasures of mobile robot's tipover problem are analyzed, stability pyramid and tipover stabil-ity index are proposed to globally determinate the mobile robot's static stability and dynamic stability. The shape shifting robot is tested by this technique under the combined disturbance of pitch, roll and yaw in simulation. The simulation result shows that this technique is effective for the analysis of mobile robot's tipover stability, especially for the reconfigurable or shape shifting modular robot. Experiments on three symmetry configurations are made under unstructured environments. The environment experiment shows the same result as that of the simulation that the triangle type configuration has the best stability. Both simulation and experiment provide a valid reference for the reconfigurable robot's potential application. 展开更多
关键词 Reconfigurable modular robot Shape shifting robot Stability pyramid Tipover stability index Unstructured environment
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Laser frequency stabilization and shifting by using modulation transfer spectroscopy 被引量:4
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作者 程冰 王兆英 +4 位作者 吴彬 许翱鹏 王启宇 徐云飞 林强 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第10期242-247,共6页
The stabilizing and shifting of laser frequency are very important for the interaction between the laser and atoms. The modulation transfer spectroscopy for the 87Rb atom with D2 line transition F = 2 →F' = 3 is use... The stabilizing and shifting of laser frequency are very important for the interaction between the laser and atoms. The modulation transfer spectroscopy for the 87Rb atom with D2 line transition F = 2 →F' = 3 is used for stabilizing and shifting the frequency of the external cavity grating feedback diode laser. The resonant phase modulator with electro-optical effect is used to generate frequency sideband to lock the laser frequency. In the locking scheme, circularly polarized pump- and probe-beams are used. By optimizing the temperature of the vapor, the pump- and probe-beam intensity, the laser linewidth of 280 kHz is obtained. Furthermore, the magnetic field generated by a solenoid is added into the system. Therefore the system can achieve the frequency locking at any point in a range of hundreds of megahertz frequency shifting with very low power loss. 展开更多
关键词 laser stabilization SPECTROSCOPY diode lasers line shapes and shifts
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Optimization of Roll Shifting Strategy of Alternately Rolling in Hot Strip Mill 被引量:5
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作者 LI Wei-gang GUO Zhao-hui +1 位作者 YI Jian LIU Xiang-hua 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2012年第5期37-42,共6页
An optimization solution to roll shifting strategy for alternately rolling campaign is presented. All the strips in a rolling campaign are divided into narrow strips and wide ones, and shifting position of narrow stri... An optimization solution to roll shifting strategy for alternately rolling campaign is presented. All the strips in a rolling campaign are divided into narrow strips and wide ones, and shifting position of narrow strips is obtained by the recursive method, and then shifting position of wide strips is optimized by NSGA-II which is a multiobjective genetic algorithm. For wide strips, a multi-objective optimization model of roll shifting strategy is pro posed, which takes 3 wear contour factors including edge smoothness, body smoothness and edge drop as optimization objectives. The Pareto optimal front of roll shifting strategy can be gained quickly by NSGA-II, which suggests a series of alternative solutions to roll shifting strategy. Analysis shows that the conflict exists among the 3 objectives. The final optimal solution is selected from the Pareto optimal solutions by the weighted-sum decision-making method. Industrial production proves the validity of the solution, and it can improve strip profile of alternately rolling, reduce strip edge wave, and extend the rolling miles of rolling campaigns. 展开更多
关键词 hot strip mill alternately rolling work roll shifting NSGA-II pareto optimal solution
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