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Enhancing thermodynamic performances and suppressing fluctuations in interacting quantum-dot thermoelectric engines
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作者 Jianhan Zhuang Qinyan Zou +5 位作者 Ziming Wang Gaoyuan Chen Jian Sun Xiang Hao Chen Wang Jincheng Lu 《Chinese Physics B》 2026年第1期392-397,共6页
Quantum dot systems emerge as promising platforms for studying nanoscale thermoelectric effects and quantum fluctuation phenomena.In this work,we investigate the thermodynamic performance of a Coulomb-blockaded quantu... Quantum dot systems emerge as promising platforms for studying nanoscale thermoelectric effects and quantum fluctuation phenomena.In this work,we investigate the thermodynamic performance of a Coulomb-blockaded quantum dot operating as a quantum heat engine using the quantum master equation approach.By incorporating full counting statistics,we analyze both average transport properties and current fluctuations in this nanoscale system.We demonstrate that electron-electron interactions significantly enhance thermoelectric performance by increasing both the output power and energy conversion efficiency.Furthermore,we show that Coulomb interactions suppress current fluctuations while preserving the validity of the thermodynamic uncertainty relation.Our results provide important insights into the interplay between quantum effects and thermodynamic principles in nanoscale heat engines. 展开更多
关键词 quantum dot thermoelectric engine Coulomb interaction current fluctuations thermodynamic uncertainty relation
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Effect of thermal fluctuations on turbulent channel flow
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作者 Xiao Liu Chengxi Zhao +2 位作者 Zhangbo Zhou Wan Cheng Ting Si 《Acta Mechanica Sinica》 2026年第1期145-161,共17页
Thermal fluctuations have been found to significantly influence the dissipation range of turbulence,an effect beyond the scope of the classical Navier-Stokes equations.In this study,we investigate their impact on turb... Thermal fluctuations have been found to significantly influence the dissipation range of turbulence,an effect beyond the scope of the classical Navier-Stokes equations.In this study,we investigate their impact on turbulent channel flow by numerically solving the fluctuating hydrodynamic equations.Simulation results confirm theoretical predictions that the energy spectrum,dominated by thermal fluctuations,follows a k2 power law.When thermal fluctuations reach sufficient intensity,they disrupt the dominant turbulent structures responsible for most of the kinetic energy,leading to a reduction in large-scale spectral energy.Additionally,thermal fluctuations increase wall skin friction by modifying mean velocity profiles.The injected energy amplifies Reynolds normal stresses while maintaining the magnitude of Reynolds shear stress.Furthermore,thermal fluctuations enhance the symmetry and homogeneity of velocity fluctuations while reducing their intermittency.Despite these effects,the balance between kinetic energy production and dissipation,including both turbulent and thermal contributions,remains preserved. 展开更多
关键词 Wall-bounded turbulence Fluctuating hydrodynamics Micro-fluid/Nano-fluid dynamics
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Giant Drag Fluctuations in Graphene-Based Electronic Double-Layer Systems
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作者 Chi Zhang Lijun Zhu +1 位作者 Lin Li Changgan Zeng 《Chinese Physics Letters》 2025年第11期271-292,共22页
Recent advances in two-dimensional layered systems have greatly enriched electronic transport studies, particularly in inter-layer Coulomb drag research. Here, systematic transport measurements were conducted in graph... Recent advances in two-dimensional layered systems have greatly enriched electronic transport studies, particularly in inter-layer Coulomb drag research. Here, systematic transport measurements were conducted in graphene-based electronic double-layer structures, revealing giant yet reproducible drag fluctuations at cryogenic temperatures. These fluctuations' characteristics, including amplitude and peak/valley spacing, are mainly determined by the drag layer's carrier dynamics rather than the drive layer's, resulting in violation of the Onsager reciprocity relation. Notably, the drag fluctuations remain observable up to 35 K, far exceeding universal conductance fluctuations within individual layers. This suggests enhanced phase coherence in inter-layer drag compared to single-layer transport, as further confirmed by quantitative analysis of auto-correlation fields of fluctuations under magnetic fields. Our findings provide new insights into quantum interference effects and their interplay with Coulomb interactions in solids. The observations of significant drag fluctuations could potentially help address chaotic signals between nearby components in nanoscale devices. 展开更多
关键词 giant drag fluctuations electronic transport studies graphene based electronic double layer systems drive layers drag fluctuations drag layers carrier dynamics cryogenic temperatures systematic transport measurements
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Local strain fluctuations enable sluggish martensitic transformation in additively manufactured NiTi alloys with<001>growth texture under tensile loading
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作者 Binbin Wang Binqiang Li +4 位作者 Yong Yang Liang Wang Baoxian Su Fuyu Dong Yanqing Su 《Journal of Materials Science & Technology》 2025年第35期276-293,共18页
Implementing additive manufacturing to NiTi(Nitinol)alloys typically enables a preferred<001>_(B2) tex-ture along the building direction.Unfortunately,this growth orientation always possesses a high criti-cal st... Implementing additive manufacturing to NiTi(Nitinol)alloys typically enables a preferred<001>_(B2) tex-ture along the building direction.Unfortunately,this growth orientation always possesses a high criti-cal stress level to induce the martensitic transformation and experiences premature failure before the formation of martensite during tensile testing.By utilizing in situ characterization technologies,in this study,we demonstrate that by fabricating a NiTi sample with complete<001>_(B2) texture using wire-fed electron beam directed energy deposition,a sluggish martensitic transformation can be achieved to re-tard the initiation of fracture under tensile loading.To discern the origins of this tensile response,we combine experiments with molecular dynamics simulations to systematically analyze the micro-scale de-tails on how internal lattice defects can select the variety of martensite variants.Using both quasi in situ transmission electron microscopy analysis and calculations of the different atomic configurations,our results indicate that the pre-existing precipitates and accumulated dislocation defects,rather than columnar boundaries,can have a positive influence on the sluggish formation of variants that can cou-ple with plastic deformation within a much wider stress interval.Specifically,only the variant favored by both internal strain/stress fluctuations around local defects and external tensile load will overcome the high-energy transition barrier of<001>_(B2)-oriented tension to nucleate and grow sluggishly.The cur-rent findings not only show how the mechanical responses can be controlled in additively manufactured NiTi alloys with<001>_(B2) texture,but also regard this understanding to be a step forward in decoding the salient underlying mechanisms for the correlating texture,defects,and phase transformation of these functional materials. 展开更多
关键词 Additive manufacturing Martensitic transformation Lattice defects Strain fluctuations NI-TI
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Forage Nutrient Fluctuations During the Dry Season:A Case Study of Tropical Grazing Land in East Nusa Tenggara,Indonesia
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作者 Grace Maranatha Putri Pandarangga +1 位作者 Yohanis Umbu Laiya Sobang Fredeicus Dedy Samba 《Research in Ecology》 2025年第4期71-84,共14页
Natural grazing land plays a crucial role in extensive ruminant livestock systems,especially in semi-arid tropical regions such as East Nusa Tenggara(ENT),Indonesia.The availability and quality of forage during the dr... Natural grazing land plays a crucial role in extensive ruminant livestock systems,especially in semi-arid tropical regions such as East Nusa Tenggara(ENT),Indonesia.The availability and quality of forage during the dry season present significant challenges.This study aimed to identify variations in grass species composition and fluctuations in forage nutritional content in natural grazing lands of ENT during the dry season(July–October 2024).Sampling was conducted in four sub-districts:two representing lowland zones and two representing highland zones.In each sub-district,four grazing fields were selected,and ten plots were sampled per grazing field,totaling 160 sampling plots.Species identification and nutrient analysis included crude protein,crude fiber,energy content,and proteinenergy ratio.Statistical analyses using ANOVA and Tukey’s multiple comparison test were performed to evaluate significant differences in nutritional parameters across months and zones.Dominant species identified were Themeda arguens,Heteropogon contortus,Brachiaria decumbens,Ischaemum timorense,Cynodon dactylon,and Pennisetum clandestinum.Results showed significant monthly fluctuations in crude protein and fiber contents(p<0.05),with protein levels decreasing from July(9.31±2.66%)to October(7.53±3.10%).Energy content and protein-energy ratio also varied significantly across the dry season.A monthly shift in dominant grass species composition was observed,influenced by environmental conditions and species adaptability.The protein-energy ratio of forage remained below optimal levels throughout the dry season,potentially limiting livestock productivity.These findings provide important scientific insights for developing climate-resilient feeding strategies and support policy formulation for sustainable tropical livestock farming in semi-arid regions. 展开更多
关键词 Dry Season FORAGE Nutrient fluctuations Tropical Grazing Land East Nusa Tenggara
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Risk Mitigation Effectiveness of Foreign Well-Known Trademark Protection During Supply Chain Fluctuations
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作者 LI Yinge 《Chinese Business Review》 2025年第1期9-20,共12页
The global supply chain turbulence has increased the difficulty of protecting foreign well-known trademarks.Although there are many studies on cross-border trademark rights protection in academia,there is relatively l... The global supply chain turbulence has increased the difficulty of protecting foreign well-known trademarks.Although there are many studies on cross-border trademark rights protection in academia,there is relatively little research on its risk mitigation effectiveness in the context of supply chain fluctuations.Based on case studies of commercial law and data statistics,the study explores the relationship between protection efficiency and market response through legal applicability.Due to the long litigation cycle and uneven law enforcement,there are differences in market regulation,weakening the protection of well-known trademarks and exacerbating supply chain uncertainty.Strengthening international legal framework cooperation and promoting law enforcement linkage can enhance protection effectiveness.In theory,enriching the theory of cross-border trademark protection and expanding research on brand rights protection in the context of global supply chains.In practice,it helps enterprises adjust their trademark layout,avoid legal risks,and improve market competitiveness.Due to the complexity of the legal environment and limitations in data acquisition,future research will strengthen data analysis,promote international cooperation in intelligent supervision,and build a more efficient cross-border well-known trademark protection mechanism. 展开更多
关键词 supply chain resilience famous trademark risk mitigation economic fluctuations intellectual property
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Multiphoton intravital microscopy in small animals of long-term mitochondrial dynamics based on super-resolution radial fluctuations
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作者 Saeed Bohlooli Darian Jeongmin Oh +8 位作者 Bjorn Paulson Minju Cho Globinna Kim Eunyoung Tak Inki Kim Chan-Gi Pack Jung-Man Namgoong In-Jeoung Baek Jun Ki Kim 《Opto-Electronic Advances》 2025年第7期6-21,共16页
We developed an imaging technique combining two-photon computed super-resolution microscopy and suction-based stabilization to achieve the resolution of the single-cell level and organelles in vivo.To accomplish this,... We developed an imaging technique combining two-photon computed super-resolution microscopy and suction-based stabilization to achieve the resolution of the single-cell level and organelles in vivo.To accomplish this,a conventional two-photon microscope was equipped with a 3D-printed holders,which stabilize the tissue surface within the focal plane of immersion objectives.Further computational image stabilization and noise reduction were applied,followed by superresolution radial fluctuations(SRRF)analysis,doubling image resolution,and enhancing signal-to-noise ratios for in vivo subcellular process investigation.Stabilization of<1μm was obtained by suction,and<25 nm were achieved by subsequent algorithmic image stabilization.A Mito-Dendra2 mouse model,expressing green fluorescent protein(GFP)in mitochondria,demonstrated the potential of long-term intravital subcellular imaging.In vivo mitochondrial fission and fusion,mitochondrial status migration,and the effects of alcohol consumption(modeled as an alcoholic liver disease)and berberine treatment on hepatocyte mitochondrial dynamics are directly observed intravitally.Suction-based stabilization in two-photon intravital imaging,coupled with computational super-resolution holds promise for advancing in vivo subcellular imaging studies. 展开更多
关键词 SRRF in vivo subcellular imaging mitochondiral dynamics multiphoton intravital microscopy super resolution radial fluctuations
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Loop-Current Fluctuations Mediated Chiral d-Wave Pairing in Kagome Lattice
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作者 Qi-Fang Li Gaopei Pan +4 位作者 Xu Zhang Satoru Nakatsuji Weilun Jiang Xiao Yan Xu Xianxin Wu 《Chinese Physics Letters》 2025年第5期123-139,共17页
Recent various experiments have provided evidence supporting the emergence of loop-current order in kagome metals. Particularly superconductivity in AV_(3)Sb_(5) is significantly enhanced when this charge order is sup... Recent various experiments have provided evidence supporting the emergence of loop-current order in kagome metals. Particularly superconductivity in AV_(3)Sb_(5) is significantly enhanced when this charge order is suppressed by pressure or doping. Distinct from magnetic order, loop-current order does not couple directly to spin and thus whether such fluctuations can enhance superconductivity remains elusive. We design a sign problem-free bilayer kagome model coupled to quantum Ising spins through bond currents and perform determinant quantum Monte Carlo simulations to explore single-particle properties and superconductivity arising from 2 × 2 loopcurrent fluctuations. We find that this loop-current order induces intriguing band folding, band broadening,and gap opening around saddle points. Remarkably, our pairing susceptibility analysis identifies a dominant enhancement of superconductivity due to loop-current fluctuations, with the dominant pairing being the chiral d-wave channel. This pairing primarily occurs within the intra-sublattice channel and involves third nearestneighbor sites, attributed to the unique sublattice texture associated with van Hove singularities. We also discuss potential experimental implications for kagome superconductors. 展开更多
关键词 kagome metals quantum ising spins quantum monte carlo simulations bond current enhance superconductivity chiral d wave pairing loop current fluctuations kagome lattice
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Acceptance effect on the N_(t)N_(p)/N_(d)^(2)ratio of light nuclei coalescence yields as a probe of nucleon density fluctuations
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作者 An Gu Michael X.Zhang 《Nuclear Science and Techniques》 2025年第3期157-166,共10页
A coalescence model was employed to form deuterons(d),tritons(t),and helium-3(^(3)He)nuclei from a uniformly-distributed volume of protons(p)and neutrons(n).We studied the ratio N_(t)N_(p)/N_(d)^(2)of light nuclei yie... A coalescence model was employed to form deuterons(d),tritons(t),and helium-3(^(3)He)nuclei from a uniformly-distributed volume of protons(p)and neutrons(n).We studied the ratio N_(t)N_(p)/N_(d)^(2)of light nuclei yields as a function of the neutron density fluctuations.We investigated the effect of finite transverse momentum(p_(T))acceptance on the ratio,in particular,the“extrapolation factor”(f)for the ratio as a function of the p_(T)spectral shape and the magnitude of neutron density fluctuations.The nature of f was found to be monotonic in p_(T)spectra“temperature”parameter and neutron density fluctuation magnitude;variations in the latter are relatively small.We also examined f in realistic simulations using the kinematic distributions of protons measured from the heavy-ion collision data.The nature of f was found to be smooth and monotonic as a function of the beam energy.Therefore,we conclude that extrapolation from limited p_(T)ranges does not create,enhance,or reduce the local peak of the N_(t)N_(p)/N_(d)^(2)ratio in the beam energy.Our study provides a necessary benchmark for light nuclei ratios as a probe for nucleon density fluctuations,an important observation in the search for the critical point of nuclear matter. 展开更多
关键词 Heavy-ion collision Critical point Light nuclei coalescence Nucleon density fluctuations
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Mobilization of heavy metals from floodplain sediments of the Yellow River during redox fluctuations
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作者 Fuyu Xie Xiaoqing Li +2 位作者 Qingxiang Yang Ying Meng Fubo Luan 《Journal of Environmental Sciences》 2025年第4期432-439,共8页
The floodplain of the Yellow River is a typical area characterized by redox fluctuations and heavy metal pollution.However,the mobilization behavior of heavy metals in floodplain sediments during redox fluctuations re... The floodplain of the Yellow River is a typical area characterized by redox fluctuations and heavy metal pollution.However,the mobilization behavior of heavy metals in floodplain sediments during redox fluctuations remains poorly understood.In this study,reductive mobilization of Fe and Mn was observed under reducing environments through reduction and dissolution,leading to the subsequent release of adsorbed As.In contrast,the mobilization of U occurred under oxic conditions,as the oxidative state of U(VI)has higher solubility.Furthermore,insignificant effects on the mobilization of Cd,Cu,Pb,and Hg were noticed during redox fluctuations,indicating higher stability of these heavymetals.Additionally,we demonstrated that carbon sources can play a key role in the mobilization of heavy metals in floodplain sediments,amplifying the reductive mobilization of Fe,Mn,As and the oxidative mobilization of U.Our findings contribute to the understanding of the biogeochemical cycling of heavy metal in floodplain sediments of the Yellow River and the factors that control this cycling. 展开更多
关键词 Biogeochemical cycling Redox fluctuation Heavy metal Carbon supplementation The Yellow River
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Improved reference-frame-independent quantum key distribution with intensity fluctuations
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作者 Zi-Qi Chen Hao-Bing Sun +1 位作者 Ming-Shuo Sun Qin Wang 《Chinese Physics B》 2025年第2期48-52,共5页
Reference-frame-independent quantum key distribution(RFI-QKD)can avoid real-time calibration operation of reference frames and improve the efficiency of the communication process.However,due to imperfections of optica... Reference-frame-independent quantum key distribution(RFI-QKD)can avoid real-time calibration operation of reference frames and improve the efficiency of the communication process.However,due to imperfections of optical devices,there will inevitably exist intensity fluctuations in the source side of the QKD system,which will affect the final secure key rate.To reduce the influence of intensity fluctuations,an improved 3-intensity RFI-QKD scheme is proposed in this paper.After considering statistical fluctuations and implementing global parameter optimization,we conduct corresponding simulation analysis.The results show that our present work can present both higher key rate and a farther transmission distance than the standard method. 展开更多
关键词 quantum key distribution intensity fluctuations decoy-state method
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Water level fluctuations shape phytoplankton community in the Xiangxi Bay from Three Gorges Reservoir
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作者 Lingchao Fang Wujuan Mi +2 位作者 Yuan Li Xiaohan Ai Yonghong Bi 《Journal of Environmental Sciences》 2025年第11期111-122,共12页
Water level fluctuations(WLFs)constituted a dominant factor controlling the structure and function of freshwater ecosystems but the mechanism of WLFs on phytoplankton community structure was still unknown.We investiga... Water level fluctuations(WLFs)constituted a dominant factor controlling the structure and function of freshwater ecosystems but the mechanism of WLFs on phytoplankton community structure was still unknown.We investigated the characteristics of phytoplankton community structure in Xiangxi Bay from January 2017 to December 2020.Results indicated water level(WL)of the Three Gorges Reservoir was divided into four distinct stages:the decreasing stage(DS),the low water level stage(LS),the storage stage(SS),and the high water level stage(HS).Notably,Cyanophyta predominated during the LS,with Microcystis sp.being the dominant species.Bacillariophyta was predominant in other three WL stages,with Melosira sp.and Cyclotella sp.as the dominant species.The highest biomass appeared in LS,whereas the lowest appeared in HS.Moreover,alpha diversity appeared to be lower in both HS and LS compared to DS and SS.Redundancy analysis showed WL as the key driver of phytoplankton community.Partial least squares path model analyses demonstrated that WL not only altered chemical factors(path coefficient=-0.62,P<0.01),thereby leading to changes in phytoplankton biomass(path coefficient=0.56,P<0.01),but also changed the physical factors(path coefficient=-0.69,P<0.01)and consequently had an impact on phytoplankton biomass(path coefficient=0.33,P<0.01).Furthermore,WL influenced phytoplankton diversity by altering chemical and physical factors.In conclusion,WL was an important factor influencing phytoplankton community,which implied that reservoir operation was the potential strategy to regulate phytoplankton communities. 展开更多
关键词 Water level fluctuations(WLFs) Phytoplankton community Xiangxi Bay(XXB)
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Identifying time zones of power fluctuations method for photovoltaic power ramp rate optimization
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作者 You Chen Xingshuo Li +3 位作者 Xiaoyang Chen Shuye Ding Yizhi Chen Wei Wang 《Global Energy Interconnection》 2025年第5期778-789,共12页
Photovoltaic(PV)systems are being increasingly implemented in the grid,and their intermittent output fluctuations threaten the stability of the grid,thereby requiring effective power ramp control(PRRC)strategies.In th... Photovoltaic(PV)systems are being increasingly implemented in the grid,and their intermittent output fluctuations threaten the stability of the grid,thereby requiring effective power ramp control(PRRC)strategies.In this study,we proposed a power fluctuation identification method to optimize the PRRC strategy.The K-means++cluster based on DTW used in this method,which clusters the historical PV power generation data into power curves corresponding to a specific weather type(sunny,cloudy,and rainy)in a time zone.Subsequently,wavelet decomposition is applied to discretize the power curves with extreme RR overrun to accurately identify the extreme fluctuation time zones.We conducted an analysis using minute-level data from a 100 kW PV plant in Arizona,which demonstrates that the proposed method can effectively identify high-risk periods.Weather patterns within the time zones were quantitatively identified using a weather probability model.A hardware-in-the-loop experimental platform was employed to validate two days of actual power data in Arizona,demonstrating the weather zoning accuracy of the method and the reasonableness of the control.The proposed methodology contributes significantly to PRRC strategy selection and parameter optimization(e.g.,ESS capacity storage allocation and APC power reserveΔP)in different time zones and weather conditions. 展开更多
关键词 Photovoltaic power fluctuation Temporal clustering Wavelet decomposition Power ramp rate control
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Fluctuations in the relationship between the Silk Road Pattern and the summer North Atlantic Oscillation
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作者 Yong Liu Zhencai Du 《Atmospheric and Oceanic Science Letters》 2025年第4期35-40,共6页
This study investigated the fluctuations in the relationship between the Silk Road Pattern(SRP)and the boreal summer North Atlantic Oscillation(SNAO).The results indicated that the SRP–SNAO relationship was relativel... This study investigated the fluctuations in the relationship between the Silk Road Pattern(SRP)and the boreal summer North Atlantic Oscillation(SNAO).The results indicated that the SRP–SNAO relationship was relatively weak during 1958–2022,which was primarily due to fluctuations,particularly the reversal in their relationship since the late 1990s.Using wavelet coherence analysis,the authors identified a strong SRP–SNAO linkage on a 4–8-yr timescale,in particular during the mid-1970s to the early/mid-1990s.This strong linkage is mainly attributable to the intensification and eastward movement of the southern part of the SNAO around the mid/late 1970s,which favored the strong connection between the SNAO and the SRP.Additionally,the interdecadal changes of the atmospheric circulations over the North Atlantic and Eurasia around the mid/late 1970s that resembled the circulation anomalies related to the strong SRP–SNAO linkage,may also have provided a favorable background for the strong connection between the two teleconnections.These findings on the fluctuations in the SRP–SNAO linkage may offer important implications for understanding the impact of the SNAO on the SRP and the variability of the SRP. 展开更多
关键词 Silk Road Pattern North Atlantic Oscillation Relationship fluctuation
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IGV叶片尾迹湍流总压脉动建模研究
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作者 彭威 李雪松 +1 位作者 顾春伟 李艳 《工程热物理学报》 北大核心 2026年第1期102-107,共6页
为了快速计算由IGV叶片尾迹湍流脉动引起的激励,本文针对重燃压气机支板和第一级动叶在共振转速下的强迫振动问题,开展了重燃压气机动叶激励源建模研究,探索了IGV尾迹湍流脉动机理,通过理论推导和LES方法建立了总压脉动和速度脉动、静... 为了快速计算由IGV叶片尾迹湍流脉动引起的激励,本文针对重燃压气机支板和第一级动叶在共振转速下的强迫振动问题,开展了重燃压气机动叶激励源建模研究,探索了IGV尾迹湍流脉动机理,通过理论推导和LES方法建立了总压脉动和速度脉动、静压脉动等参数的关系,进一步通过时均雷诺应力等参数定义脉动因子,提出了基于时均雷诺应力的IGV尾迹湍流总压脉动模型,实现了较宽频率范围内的尾迹湍流总压脉动幅值预测,通过LES结果验证了模型的准确性和适用性,为计算IGV叶片尾迹湍流脉动引起的激励力提供了进口边界条件。 展开更多
关键词 重燃压气机 强迫振动 激励源 尾迹 湍流脉动
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三相四线制逆变器独立中线模块的高带宽复合控制策略与参数优化设计方法
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作者 赵景涛 雷家兴 +2 位作者 郑舒 吴志 陈永华 《中国电机工程学报》 北大核心 2026年第3期1165-1177,I0025,共14页
带独立中线模块的三相四线制逆变器具有零序电流小、输出中点电压与三相电压控制解耦等优势,其正常运行的基础是中点电压稳定。传统的比例-积分(proportional integral,PI)双环控制策略受制于其有限带宽,对中点电压波动的抑制效果不足,... 带独立中线模块的三相四线制逆变器具有零序电流小、输出中点电压与三相电压控制解耦等优势,其正常运行的基础是中点电压稳定。传统的比例-积分(proportional integral,PI)双环控制策略受制于其有限带宽,对中点电压波动的抑制效果不足,易引起输出共模扰动、降低波形质量。为此,提出一种内环状态反馈和外环PI复合的中点电压控制策略及基于目标响应驱动的控制参数优化设计方法。所提策略在离散域建立受控对象的精细化数学模型,基于系统整体设计理念,通过预设目标传递函数逆向获得所有控制参数的解析表达式,并分析系统可实现控制带宽与闭环零极点位置之间的量化关系;在此基础上,研究不同控制带宽下系统对零序电流低频分量的抑制效果及采样延时和噪声对控制性能的影响规律,为实际应用中控制参数的最优设计提供指导;同时,分析滤波参数宽幅变化对系统闭环控制性能的影响。实验结果表明,所提方法可在不放大噪声的同时显著提高控制带宽,进而有效抑制不对称/谐波负载扰动下的中点电压波动、提高输出波形质量,且具有较高的参数鲁棒性。 展开更多
关键词 独立中线模块 中点电压波动 状态反馈控制 高带宽
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极端气候对河南花生单产的影响及其灾损评估
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作者 黄进 张方敏 《应用生态学报》 北大核心 2026年第1期180-188,共9页
花生是河南省特色优势作物,识别单产波动与极端气候的联系有利于保障种植安全。以河南省17个地市的花生单产为研究对象,分析1988—2022年间种植效率区域差异的演变过程;基于气候产量与9种极端气候指数的多元回归分析量化了极端气候对花... 花生是河南省特色优势作物,识别单产波动与极端气候的联系有利于保障种植安全。以河南省17个地市的花生单产为研究对象,分析1988—2022年间种植效率区域差异的演变过程;基于气候产量与9种极端气候指数的多元回归分析量化了极端气候对花生的影响;基于气候减产率和逼近理想解排序法分析花生综合气候灾损的时空演变格局。结果表明:1988—2022年间,研究区花生种植效率的区域均衡性呈现增强趋势,但西部地市的单产依旧显著低于东部高产区;研究期间,生育期内各月的高温事件普遍加剧,特别是近60%站点在8月呈现显著增强趋势,而同期强降水和干旱的增强并不显著;花生主导致灾因子具有显著的区域差异,研究区南部、东部及北部的主导致灾因子为强降水,中西部为高温干旱;极端气候导致12个地市花生显著减产0.8%~6.7%,对其余5个地市未产生显著影响;花生气候灾损在1988—2009年间呈现较高强度,在2010—2022年间处于较低水平。 展开更多
关键词 花生 单产波动 极端气候 气候产量 气候灾损
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天然气凝析液管道水溶性清管球的清管特性
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作者 吕宇玲 李佳薇 +3 位作者 李亚东 李得恩 陈建恒 罗小明 《化工进展》 北大核心 2026年第1期535-544,共10页
天然气凝析液管道内积液增多、压差增大及水合物生成等问题对管道的安全高效运行构成了严重威胁,定期清管成为解决这些问题的关键手段。然而,传统清管球在小口径起伏管路中易卡堵、在多分支管路中难追踪等问题,给管道带来运行风险。本... 天然气凝析液管道内积液增多、压差增大及水合物生成等问题对管道的安全高效运行构成了严重威胁,定期清管成为解决这些问题的关键手段。然而,传统清管球在小口径起伏管路中易卡堵、在多分支管路中难追踪等问题,给管道带来运行风险。本文提出了一种新型水溶性清管球,该清管球在设定压差下会破碎,碎片可溶于水,不会对管道造成堵塞并且无需追踪。研究采用理论与实验相结合的方法,研发了具有合理强度和溶解特性的水溶性清管球,并通过环道实验测试了水溶性清管球的清管特性。研究结果表明,水溶性清管球运行稳定、合理溶解,避免了卡堵风险,清管效率高,实现了管道的高效、安全清洁。水溶性清管球采用改性水溶性树脂与弹性中空复合结构设计,具有缓溶耐磨特性(溶解时间12h/mm),其抗拉强度达20.82MPa,耐磨耗量为0.2952cm3/km;在中等过盈量(1%~2%)和适中驱动气速(6~8m/s)条件下运行效果最佳;驱动气速提升可有效克服管道积液阻力,但当积液量超过阈值时,需通过降低过盈量或进一步提高气速来改善清管效果;过盈量增加会增大管壁摩擦力,延长清管时间并提高启动压力。本文为水溶清管技术在管道积液清除和安全运行的工程应用提供了理论依据和实践指导。 展开更多
关键词 天然气凝析液管道 水溶性清管球 溶解 破碎 运行速度 压力波动
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双负载三电平整流器功率解耦控制和电容电压波动抑制
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作者 姜卫东 徐星俣 +3 位作者 王金平 刘欣然 杨柳 钟敏 《中国电机工程学报》 北大核心 2026年第1期376-388,I0028,共14页
近年来,三电平中点钳位型整流器在各个领域得到广泛应用,随着“光伏-储能-充电桩”三位一体的微电网系统的兴起,其上、下直流侧电压和上、下负载功率的独立稳定控制变得愈发关键。该文针对上述需求提出一种双负载T型三电平整流器的通用... 近年来,三电平中点钳位型整流器在各个领域得到广泛应用,随着“光伏-储能-充电桩”三位一体的微电网系统的兴起,其上、下直流侧电压和上、下负载功率的独立稳定控制变得愈发关键。该文针对上述需求提出一种双负载T型三电平整流器的通用控制方法。首先,基于载波脉宽调制方法分析双负载T型三电平整流器直流零序电压注入与上、下直流侧功率分配的关系,并给出功率解耦控制方法;其次,分析并绘制出不同调制度下,上、下直流侧平均功率占比的极限情况,并依据上、下直流侧瞬时功率恒定的控制目标求解出零序电压瞬时分量来抑制直流侧电容电压波动;最后,通过实验验证上述方法的可行性和有效性。 展开更多
关键词 双负载整流器 零序电压注入 功率分配关系 功率解耦 电容电压波动抑制
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度拉糖肽联合甘精胰岛素治疗2型糖尿病患者的疗效
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作者 高珊 苏亚 +2 位作者 吴贵福 艾力亚斯·阿不拉 李晓燕 《中国药物应用与监测》 2026年第1期77-81,共5页
目的 探讨度拉糖肽联合甘精胰岛素治疗2型糖尿病(T2DM)的疗效。方法 采用前瞻性对照研究。选取2022年12月至2023年12月于陕西省人民医院就诊的T2DM患者,根据随机数字表法将其分为观察组(采用度拉糖肽联合甘精胰岛素治疗)和对照组(仅采... 目的 探讨度拉糖肽联合甘精胰岛素治疗2型糖尿病(T2DM)的疗效。方法 采用前瞻性对照研究。选取2022年12月至2023年12月于陕西省人民医院就诊的T2DM患者,根据随机数字表法将其分为观察组(采用度拉糖肽联合甘精胰岛素治疗)和对照组(仅采用甘精胰岛素治疗),每组各52例,均持续接受治疗3个月。分析治疗前及治疗3个月后观察组和对照组患者的血糖水平相关指标、血糖波动指标、胰岛β细胞功能相关指标、疾病相关生化指标的变化,以及治疗3个月期间的不良反应。结果 治疗3个月后观察组患者的平均血糖波动幅度、最大血糖波动幅度、日间血糖平均绝对差、胰岛素抵抗指数、空腹血糖、餐后2h血糖、糖化血红蛋白、甘油三酯葡萄糖乘积指数分别为[(4.36±0.55)mmol/L、(4.13±0.60)mmol/L、(1.45±0.11)mmol/L、(1.22±0.14)、(5.91±0.61)mmol/L、(7.04±0.47)mmol/L、(5.41±0.32)%、(7.09±0.62)],均低于对照组[(4.69±0.72)mmol/L、(4.41±0.72)mmol/L、(1.82±0.24)mmol/L、(1.38±0.20)、(6.29±0.52)mmol/L、(7.56±0.96)mmol/L、(5.77±0.41)%、(7.73±0.78)],差异有统计学意义(t=2.626、2.154、10.107、4.726、3.419、3.508、4.991、4.632,均P<0.05);而观察组患者的胰岛β细胞功能指数、胰岛素样生长因子1、G蛋白偶联受体内源性配体、微小RNA-126、微小RNA-21水平分别为(138.29±18.73)、(139.18±15.56)μg/L、(1 683.31±201.04)ng/L、(22.12±3.25)、(0.87±0.10),均高于对照组[分别为(124.75±15.24)、(133.25±12.47)μg/L、(1 584.39±216.18)ng/L、(19.97±2.86)、(0.79±0.08)],差异有统计学意义(t=4.044、2.144、2.416、3.581、4.505,均P<0.05)。观察组患者的不良反应发生率为3.85%(2/52),高于对照组的1.92%(1/52),但差异无统计学意义(Fisher精确检验,P≈1.000)。结论 度拉糖肽联合甘精胰岛素治疗T2DM可有效促进胰岛β细胞功能恢复,减小血糖波动幅度,改善胰岛素抵抗,帮助维持血糖稳定。 展开更多
关键词 度拉糖肽 甘精胰岛素 2型糖尿病 血糖波动 甘油三酯葡萄糖乘积指数
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