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A phenology-based vegetation index for improving ratoon rice mapping using harmonized Landsat and Sentinel-2 data 认领 引用 被引量：7
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作者 Yunping Chen Jie Hu +6 位作者 Zhiwen Cai Jingya Yang Wei Zhou Qiong Hu Cong Wang Liangzhi You Baodong Xu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第4期1164-1178,共15页
Ratoon rice,which refers to a second harvest of rice obtained from the regenerated tillers originating from the stubble of the first harvested crop,plays an important role in both food security and agroecology while r... Ratoon rice,which refers to a second harvest of rice obtained from the regenerated tillers originating from the stubble of the first harvested crop,plays an important role in both food security and agroecology while requiring minimal agricultural inputs.However,accurately identifying ratoon rice crops is challenging due to the similarity of its spectral features with other rice cropping systems(e.g.,double rice).Moreover,images with a high spatiotemporal resolution are essential since ratoon rice is generally cultivated in fragmented croplands within regions that frequently exhibit cloudy and rainy weather.In this study,taking Qichun County in Hubei Province,China as an example,we developed a new phenology-based ratoon rice vegetation index(PRVI)for the purpose of ratoon rice mapping at a 30 m spatial resolution using a robust time series generated from Harmonized Landsat and Sentinel-2(HLS)images.The PRVI that incorporated the red,near-infrared,and shortwave infrared 1 bands was developed based on the analysis of spectro-phenological separability and feature selection.Based on actual field samples,the performance of the PRVI for ratoon rice mapping was carefully evaluated by comparing it to several vegetation indices,including normalized difference vegetation index(NDVI),enhanced vegetation index(EVI)and land surface water index(LSWI).The results suggested that the PRVI could sufficiently capture the specific characteristics of ratoon rice,leading to a favorable separability between ratoon rice and other land cover types.Furthermore,the PRVI showed the best performance for identifying ratoon rice in the phenological phases characterized by grain filling and harvesting to tillering of the ratoon crop(GHS-TS2),indicating that only several images are required to obtain an accurate ratoon rice map.Finally,the PRVI performed better than NDVI,EVI,LSWI and their combination at the GHS-TS2 stages,with producer's accuracy and user's accuracy of 92.22 and 89.30%,respectively.These results demonstrate that the proposed PRVI based on HLS data can effectively identify ratoon rice in fragmented croplands at crucial phenological stages,which is promising for identifying the earliest timing of ratoon rice planting and can provide a fundamental dataset for crop management activities. 展开更多
关键词 ratoon rice phenology-based ratoon rice vegetation index(PRVI) phenological phase feature selection Harmonized Landsat Sentinel-2 data
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照料史、隔代照料对我国中老年人健康的影响——基于Harmonized CHARLS的研究 认领 引用 被引量：36
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作者 陈英姿 孙伟 《人口学刊》 CSSCI 北大核心 2019年第5期45-56,共12页
现代社会家庭规模以小型化和核心化为主,但不论农村还是城市,孩子的生养教化等功能仍由家庭承担,很多祖辈依然承担着照料孙辈的任务,隔代照料在现代社会仍发挥重要作用。隔代照料对照料者的健康会产生一定的影响,这种影响因“居住安排... 现代社会家庭规模以小型化和核心化为主,但不论农村还是城市,孩子的生养教化等功能仍由家庭承担,很多祖辈依然承担着照料孙辈的任务,隔代照料在现代社会仍发挥重要作用。隔代照料对照料者的健康会产生一定的影响,这种影响因“居住安排”而异,同时照料状态的转变,即照料角色的获取或退出、持续或中断等不同“照料史”的变化对照料者的健康也有影响。本文采用南加州大学经济与社会研究中心提供的Harmonized CHARLS 2013-2015年追踪数据,选取45-80岁的中老年人为研究对象,以虚弱指数表征健康结果,运用滞后变量回归模型,从“居住安排”和“照料史”两个维度研究隔代照料行为对照料者健康的影响。研究发现:与子女同住且提供隔代照料对老年人的健康有改善作用;照料史的动态变化影响照料者健康,新进入照料角色对照料者的健康有改善作用;在照料孙辈的同时,祖辈出于利他主义动机为成年子女提供经济支持能显著改善其健康状况;男性在提供隔代照料过程中更容易经历健康的亏损,尤其是单身的男性照料者;以上结论仅适用于70岁以下的照料者,对于70岁及以上的老年群体,长期提供隔代照料会加重健康负担。 展开更多
关键词 隔代照料 照料史 虚弱指数 Harmonized CHARLS
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Normative Analysis and Strategy Research on Harmonized Development of Modern Industrialization, Urbanization, Agricultural Modernization and IT Application 认领 引用
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作者 蔡世忠 《Agricultural Science & Technology》 CAS 2014年第4期697-702,712,共6页
Targeting modernization, we should keep to the Chinese-style path of car- rying out industrialization in a new way and advancing IT application, urbanization, and agricultural modernization. In the research, the scien... Targeting modernization, we should keep to the Chinese-style path of car- rying out industrialization in a new way and advancing IT application, urbanization, and agricultural modernization. In the research, the scientific concepts of IT applica- tion, urbanization, agricultural modernization and industrialization were illustrated and the interrelations were analyzed, with measures on harmonized development pro- posed based on existing problems. 展开更多
关键词 Harmonized development of Modern Industrialization, Urbanization, Agri- cultural Modernization and IT application Normative analysis Strategy research China
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Power-Sharing Enhancement Using Harmonized Membership Fuzzy Logic Droop Control Based Micro-Grid 认领 引用 被引量：1
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作者 W.J.Praiselin J.Belwin Edward 《Intelligent Automation & Soft Computing》 SCIE 2023年第5期1395-1415,共21页
The contribution of Renewable Energy Resources(RER)in the process of power generation is significantly high in the recent days since it paves the way for overcoming the issues like serious energy crisis and natural con... The contribution of Renewable Energy Resources(RER)in the process of power generation is significantly high in the recent days since it paves the way for overcoming the issues like serious energy crisis and natural contamination.This paper deals with the renewable energy based micro-grid as it is regarded as the apt solution for integrating the RER with the electrical frameworks.As thefixed droop coefficients in conventional droop control approaches have caused various limitations like low power-sharing and sudden drops of grid voltage in the Direct Current(DC)side,the Harmonized Membership Fuzzy Logic(MFL)droop control is employed in this present study.This proposed droop control for the hybrid PV-wind-battery system with MFL assists in achieving proper power-sharing and minimizing Total Harmonic Distortion(THD)in the emer-gency micro-grid.It eradicates the deviations in voltage and frequency with itsflexible and robust operation.The THD is reduced and attains the value of 3.1%compared to the traditional droop control.The simulation results of harmo-nized MFL droop control are analogized with the conventional approaches to vali-date the performance of the proposed method.In addition,the experimental results provided by the Field Programmable Gate Array(FPGA)based laboratory setup built using a solar photovoltaic(PV)and wind Permanent Magnet Synchro-nous Generator(PMSG)reaffirms the design. 展开更多
关键词 Micro-grid harmonized droop control fuzzy power-sharing total harmonic distortion
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Prevalence of metabolic syndrome in type 2 diabetic patients: A comparative study using WHO, NCEP ATP III, IDF and Harmonized definitions 认领 引用
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作者 Mun Chieng Tan Ooi Chuan Ng +3 位作者 Teck Wee Wong Anthony Joseph Yoke Mun Chan Abdul Rahman Hejar 《Health》 2013年第10期1689-1696,共8页
To determine the prevalence of metabolic syndrome (MetS) in Malaysian type 2 diabetic patients using WHO, NCEP ATP III, IDF and the new Harmonized definitions, and the concordance between these definitions. This study... To determine the prevalence of metabolic syndrome (MetS) in Malaysian type 2 diabetic patients using WHO, NCEP ATP III, IDF and the new Harmonized definitions, and the concordance between these definitions. This study involved 313 patients diagnosed with type 2 diabetes mellitus (T2DM) at two Malaysian tertiary hospitals. Socio-demographic data were assessed using a pre-tested interviewer-administered structured questionnaire. Anthropometric measurements were carried out according to standard protocols. Clinical and laboratory characteristics were examined. Kappa (k) statistics were used for the agreement between the four MetS definitions. The overall prevalence rates of MetS (95% CI) were 95.8% (93.6-98.1), 96.1% (94.0-98.3), 84.8% (80.8-88.9) and 97.7% (96.1-99.4) according to the WHO, NCEP ATP III, IDF and the Harmonized definitions, respectively. The Kappa statistics demonstrated a slight to substantial agreement between the definitions (k = 0.179-0.875, p k = 0.875, p hest specificity (100%) in identifying MetS. In conclusion, the new Harmonized criteria established the highest prevalence of MetS among the four definitions applied. There was a very good concordance between the WHO and NCEP ATP III criteria. The extremely high prevalence of MetS observed in type 2 diabetic patients indicates an impending pandemic of CVD risk in Malaysia. Aggressive treatment of MetS components is required to reduce cardiovascular risk in T2DM. 展开更多
关键词 Metabolic Syndrome Type 2 Diabetes Mellitus (T2DM) World Health Organization (WHO) Third Report of the National Cholesterol Education Expert Panel on Detection Evaluation Treatment of High Blood Cholesterol in Adults (NCEP ATP III) International Diabetes Federation (IDF) Harmonized Definition
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On a broadband vibration isolator with tunable stiffness:from quasi-zero-stiffness to zero-stiffness behavior 认领 引用 被引量：2
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作者 N.A.SAEED Lei HOU +3 位作者 Haiming YI A.A.SHUKUR S.M.ALAMRY S.M.EL-SHOURBAGY 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2026年第2期255-282,共28页
A novel vibration isolation system designed for superior performance in low-frequency environments is proposed in this work.The isolator is based on a unique hexagonal arrangement of linear springs,allowing for an adj... A novel vibration isolation system designed for superior performance in low-frequency environments is proposed in this work.The isolator is based on a unique hexagonal arrangement of linear springs,allowing for an adjustable geometric configuration via the initial inclination angle.Based on the principle of Lagrangian mechanics,the equation of motion governing the structural dynamics is rigorously derived.The system is modeled as a strongly nonlinear single-degree-of-freedom dynamical system,loaded with a normalized payload and subject to harmonic base excitation.To analyze the steady-state response,the harmonic balance method is employed,providing accurate predictions of the payload's vibration amplitude and displacement transmissibility as functions of both the base excitation amplitude and frequency.The analysis reveals a direct relationship between the isolator's geometric and stiffness parameters and its load-bearing capacity,leading to the identification of three distinct operational regimes.Depending on the unloaded initial inclination angle,the equivalent stiffness ratio,and the payload design configuration,the system can exhibit one of three vibration isolation modes:(i)the quasizero stiffness(QZS)isolation mode,(ii)the zero linear stiffness with controllable nonlinear stiffness,and(iii)the full-band perfect zero stiffness.The vibration isolation performance of the proposed structure is thoroughly discussed for all three oscillation modes in terms of frequency response curves,displacement transmissibility,and time-domain responses.The key novel finding is that this structure can operate as a full-band,high-performance vibration isolator when the initial inclination angle is designed to be a right angle,enabling full isolation of the maximum possible payload.Moreover,the analytical results and numerical simulations demonstrate that the isolator's displacement transmissibility T with the unit dB tends to-∞as the air-damping coefficient approaches zero,enabling ideal vibration isolation across the entire excitation frequency range.These analytical insights are validated through comprehensive numerical simulations,which show excellent agreement with the theoretical predictions. 展开更多
关键词 nonlinear vibration isolation quasi-zero stiffness(QZS)structure full-band vibration isolator harmonic balance method displacement transmissibility
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Design of rare earth borate short-wave UV nonlinear optical crystals with strengthened second harmonic generation activities via cationic modification strategy 认领 引用 被引量：1
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作者 Huijian Zhao Jie Song +4 位作者 Shuaifeng Li Xianghao Kong Conggang Li Ning Ye Zhanggui Hu 《Chinese Chemical Letters》 SCIE CAS CSCD 2026年第6期662-666,共5页
Ultraviolet(UV)nonlinear optical(NLO)crystals have received substantial interest in advanced laser technology.However,tailoring a UV NLO material with a large second harmonic generation(SHG)response and good UV transp... Ultraviolet(UV)nonlinear optical(NLO)crystals have received substantial interest in advanced laser technology.However,tailoring a UV NLO material with a large second harmonic generation(SHG)response and good UV transparency remains a challenge.Here,inspired by the classic A3-RE2-[BO3]3 parent template,two new rare-earth borate NLO crystals,RbNa2La2(BO3)3(RNLBO-Ⅰ)and Rb0.681Na2.319La2(BO3)3(RNLBO-Ⅱ),were extracted by merging larger ionic radius cations Rb+and La3+simultaneously using a chemical substitution-oriented strategy.As expected,both compounds achieve significant enhancements in SHG activities,reaching 4.5×and 4.3×KDP,respectively,exceeding three times that of the isomorphic Na3Gd2B3O9.Notably,RNLBO-Ⅰdisplayed the highest SHG response among alkali metal RE-borate NLO crystals containing isolated[BO3]groups in the short-wave UV region.Moreover,RNLBO-Ⅰand-Ⅱdemonstrated short UV cutoff edges at 213 and 207 nm,corresponding to wide bandgaps of 5.3 and 5.6 eV,respectively.Additionally,theoretical calculations and dipole moment analysis were conducted to clarify the origin of the enhanced SHG activities of RNLBO-Ⅰand-Ⅱ.The optimal balance between SHG intensity and UV transparency in RNLBO-Ⅰand-Ⅱunderscores their potential as UV NLO candidates and offers valuable insights for fabricating new advanced UV NLO materials. 展开更多
关键词 Rare-earth borates Second harmonic generation Chemical substitution strategy Microscopic polarizability UV nonlinear optical crystals
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A full information expression model for track irregularity based on stochastic harmonic functions in vehicle-turnout structure stochastic vibration analysis 认领 引用 被引量：1
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作者 Xueyang Tang Xiaopei Cai +1 位作者 Jingmang Xu Fei Yang 《Railway Engineering Science》 EI 2026年第2期349-369,共21页
Turnout irregularity significantly affects the stochastic vibration behavior of vehicle-turnout structures.This study proposes a fitting formula for the turnout irregularity spectrum and develops a turnout irregularit... Turnout irregularity significantly affects the stochastic vibration behavior of vehicle-turnout structures.This study proposes a fitting formula for the turnout irregularity spectrum and develops a turnout irregularity full information expression model(TIFIEM)using a stochastic harmonic function.The model is applied to vehicle-turnout structure stochastic vibration and reliability analysis.Findings suggest that the Hamming window method,with a window length of 4096 points,is optimal for estimating the turnout irregularity spectrum.It is recommended to fit the power spectral density(PSD)using a 5th-order polynomial for better accuracy.The TIFIEM effectively addresses randomness in amplitude,frequency,and phase.An analysis of 250 irregularity samples is sufficient for the desired accuracy.Additionally,the PSD amplitude at various frequency points follows a Chi-square distribution with 2°of freedom.Regions 3-7 m from the tip of the switch rail on the straight switch rail and 53-54 m on the point rail are most susceptible to wear.When the vehicle passes through the turnout at 300 km/h,the reliability of vehicle-turnout structures at the crossing panel decreases to 95.8%. 展开更多
关键词 High-speed railway Vehicle-turnout coupling dynamics Turnout irregularity spectrum Stochastic harmonic function Probability density evolution method
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Measuring the Coulomb time shift in high-order harmonic generation 认领 引用
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作者 Shengjun Yue Siqi Song +3 位作者 Ruofeng Zhong Jiangkun Li Haiyuan Yu Hongchuan Du 《Chinese Physics B》 SCIE EI CAS CSCD 2026年第4期61-70,共10页
High-order harmonic generation(HHG),a key nonlinear phenomenon in strong-field physics,enables ultrafast detection on the attosecond timescale.Quantifying ionizationecombination times is essential for trajectory-resol... High-order harmonic generation(HHG),a key nonlinear phenomenon in strong-field physics,enables ultrafast detection on the attosecond timescale.Quantifying ionizationecombination times is essential for trajectory-resolved highharmonic spectroscopy and for benchmarking its temporal resolution.In this review,we summarize our recent studies[Phys.Rev.A 105 L041103(2022),Phys.Rev.A 106023117(2022),Phys.Rev.A 107063102(2023),Phys.Rev.A111039902(2025)]on the role of electron-core interactions in HHG.Employing the classical trajectory model,analytical R-matrix theory,and numerical solutions of time-dependent Schrodinger equations for helium,we reveal how Coulomb attraction induces subtle shifts in ionization and recombination times.Such effects emerge as observable signatures under orthogonally polarized bichromatic fields at high probe frequencies.Because of the direct experimental relevance of these findings,this review seeks to stimulate further experimental efforts to control and resolve electron dynamics in HHG.In the future,it will be of great interest to(i)refine retrieval methods by incorporating Coulomb corrections beyond the staticfield approximation,and(ii)advance two-color detection techniques with the capability to reconstruct complete quantum trajectories in HHG. 展开更多
关键词 high-order harmonic generation ultrafast electron dynamics Coulomb effects attosecond science
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Role of trajectory symmetry in solid high-order harmonic generation 认领 引用
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作者 Shuang Wang Yu Zhao +3 位作者 Hui-Rong Wang Yun-He Xing Xiao-Xin Huo Jun Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2026年第4期425-431,共7页
High-order harmonic generation(HHG)from a ZnO crystal has been investigated theoretically using a two-band model driven by a few-cycle laser pulse.We observe that harmonics in the cut-off region exhibit periodic frequ... High-order harmonic generation(HHG)from a ZnO crystal has been investigated theoretically using a two-band model driven by a few-cycle laser pulse.We observe that harmonics in the cut-off region exhibit periodic frequency shifts with changes in the carrier envelope phase(CEP)of the laser field.When the CEP of the laser pulse is an integer multiple of π,the cut-off region is dominated by even-order harmonics rather than odd-order harmonics.To illustrate the physical mechanism behind the even-order harmonics,we track the trajectories of electrons and holes between two successive halfcycles by performing time-frequency analysis and applying the recollision model.The results show that the maximum electron displacement is symmetric between successive half-cycles for odd-order harmonics.In contrast,the half-cycle symmetry of the maximum displacement is broken in the case of even-order harmonics. 展开更多
关键词 high-order harmonic generation recollision model trajectory analyses
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Improvements in vibroseis source technology towards low frequencies 认领 引用
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作者 Ming-tao Nie Zhou-hong Wei +6 位作者 Yong-fei Qi Yang Liu Yong-an Xu Cheng-kuan Zhou Sheng-kui Cong Hai Ling Gene-L.Wei 《Applied Geophysics》 SCIE CSCD 2026年第1期285-296,432,共12页
Acquiring low-frequency seismic data using vibroseis techniques has become a routine operation in land seismic survey.Successful low-frequency vibroseis acquisition requires vibroseis source technology to have signica... Acquiring low-frequency seismic data using vibroseis techniques has become a routine operation in land seismic survey.Successful low-frequency vibroseis acquisition requires vibroseis source technology to have signicant improvements in two aspects:(1)the seismic vibrator mechanical and hydraulic systems that are capable of maximally generating and transmitting the vibrator ground force;(2)the seismic vibrator control electronics that can greatly minimize the harmonic distortion noise of the vibrator ground force,particularly at low frequencies.With these understandings,a new generation low frequency seismic vibrator is designed.Field tests have demonstrated that this new generation low frequency vibrator produces and transmits a noticeable low frequency energy as low as 1.5 Hz.In addition,the vibrator controller embedded with harmonic distortion reduction(HDR)control features reduces the harmonic distortion noise at low frequencies. 展开更多
关键词 vibroseis harmonic distortion reduction low frequency
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High harmonic generation in solids driven by optical skyrmions 认领 引用
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作者 Jianing Zhang Zijian Lyu +4 位作者 Xiulan Liu Guanglu Yuan Zhengliang Li Yunquan Liu Liang-You Peng 《Advanced Photonics Nexus》 CSCD 2026年第1期224-235,共12页
With their intricate vectorial structures in space,optical skyrmions have significantly expanded the landscape of topological optics and light-matter interactions.We theoretically investigate high harmonic generation ... With their intricate vectorial structures in space,optical skyrmions have significantly expanded the landscape of topological optics and light-matter interactions.We theoretically investigate high harmonic generation in crystals driven by optical skyrmions.We find that although the skyrmion number is not conserved,the resulting high-order harmonics can exhibit a distinctive multi-vortex structure,whose features are shaped by both the topology of the optical skyrmions and the rotational symmetry of the crystal.The position of the vortex centers can be effectively tuned by employing different types of optical skyrmions.To elucidate the underlying physics,we develop a multi-absorption channel model based on the conservation laws of spin and orbital angular momentum.Our work explores the role of optical topology in extreme nonlinear light-matter interactions,offering new opportunities for the formation and manipulation of optical vortices and novel structured light fields in the visible and ultraviolet regimes. 展开更多
关键词 skyrmions high harmonic generation optical vortex spin conservation law
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Synthesis of two-dimensional Dirac semi-metallic NiTe as high-performance contacts for MoS2 transistors 认领 引用
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作者 Yingying Liu Yong Liu +16 位作者 Liqiang Zhang Xiang Lan Chen Yi Jingmei Tang Shanhao Li Yanru Wang Huan Cheng Kun He Ping Lu Zucheng Zhang Di Wang Hongmei Zhang Yukun Guo Yani Jiang Shaojun Liu Shula Chen Xidong Duan 《Nano Materials Science》 EI CAS CSCD 2026年第4期886-892,共7页
Two-dimensional Dirac semi-metals have attracted extensive attention for their potential applications in nextgeneration electronics,optoelectronics and quantum technologies.However,numerous topological semimetals pred... Two-dimensional Dirac semi-metals have attracted extensive attention for their potential applications in nextgeneration electronics,optoelectronics and quantum technologies.However,numerous topological semimetals predicted by theory have not yet been experimentally confirmed.Here,we report the controlled synthesis of high-quality NiTe nanosheets via the chemical vapor deposition method.Theoretical analysis confirms the semi-metallic nature of centrosymmetric NiTe and elucidates that its unusual second harmonic generation response originates from the electron transitions between linear dispersed bands near Dirac cone.Furthermore,NiTe nanosheets exhibit an ultra-high conductivity exceeding 10~6 S m-1,rivaling noble metal-based Dirac semimetals.Dirac semi-metallic NiTe serves as a contact electrode for MoS2field-effect transistors,showing a remarkable apparent carrier mobility of 22.45 cm2V-1s-1,which is 6.43 times higher than that of the Au-MoS2device.These findings establish NiTe as an ideal platform for exploring topological quantum states and advancing high-performance electronic devices. 展开更多
关键词 2D Dirac semi-metals Chemical vapor deposition Controlled synthesis Unusual second harmonic generation response Contact electrode
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LPF-free Harmonic Current Control in Multi-synchronous Reference Frames for Dual Three-phase PMSMs 认领 引用
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作者 Yulei Yang Qian Wang +1 位作者 Fangrui Wei Yichen Yu 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2026年第2期216-227,共12页
Harmonic current regulation in multi-phase motor drives remains challenging under dynamic operating conditions due to non-sinusoidal back electromotive force(EMF)and inverter nonlinearities,which introduce dominant lo... Harmonic current regulation in multi-phase motor drives remains challenging under dynamic operating conditions due to non-sinusoidal back electromotive force(EMF)and inverter nonlinearities,which introduce dominant low-order harmonics.Multi-synchronous reference frame(MSRF)based methods are widely adopted for multi-frequency current regulation;however,conventional implementations typically rely on low-pass filters(LPFs)for harmonic decoupling,introducing detection delay and phase distortion that limit transient performance.This paper proposes an LPF-free MSRF-based harmonic current control method for dual three-phase permanent magnet synchronous motor(DTP-PMSM)drives.By introducing harmonic transformation matrix coefficients(HTMCs),the proposed method retains the independent regulation of multiple harmonic components within the MSRF framework,while eliminating the filtering step in the harmonic decoupling path,without the need for harmonic plane reconstruction or additional coordinate transformations.To support adaptive changes,a Goertzel-based harmonic amplitude extraction scheme is employed to periodically update the HTMC.Experimental results demonstrate that the proposed method significantly enhances dynamic performance,achieving a 19.3% reduction in speed transition stabilization time compared to other methods.The proposed LPF-free formulation provides a practical solution for MSRF-based harmonic current control in industrial motor drive applications where fast dynamic response is required. 展开更多
关键词 Low-pass filter(LPF)-free harmonic decoupling Multi-synchronous reference frame(MSRF) Multi-frequency current control Harmonic current suppression Industrial motor drives Dual three-phase permanent magnet synchronous motors(DTP-PMSMs)
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TcEnhancement Induced by Quantum Ionic Vibrations in Compressed Stannane of P63/mmc Phase 认领 引用
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作者 Mi Pang Pugeng Hou +2 位作者 Mingqi Li Wenjia Shi Yao Ma 《Chinese Physics Letters》 SCIE EI CAS CSCD 2026年第3期260-269,共10页
High-pressure hydrides have emerged as promising superconducting materials,attracting considerable attention in recent years.In this work,by combining the stochastic self-consistent harmonic approximation with first-p... High-pressure hydrides have emerged as promising superconducting materials,attracting considerable attention in recent years.In this work,by combining the stochastic self-consistent harmonic approximation with first-principles calculations,we elucidate crucial corrections to the vibrational and superconducting properties arising from quantum and anharmonic ionic vibrations of SnH4 in P63/mmc phase at 150–240 GPa.Compared with the classical harmonic approximation,inclusion of these effects results in a pronounced softening(over 500 cm−1)of hydrogen-derived optical phonon modes,and increases the superconducting critical temperature(Tc)from 65 K to 79 K(μ*=0.1;isotropic Migdal–Eliashberg theory),corresponding to a 22%enhancement.Forμ*=0.13,the predicted Tc is approximately 70 K.Analysis of the Eliashberg spectral function confirms that hydrogen vibrational modes constitute the dominant tuning mechanism.These results provide quantitative insights into quantum ionic effects in hydride superconductors. 展开更多
关键词 high pressure hydrides quantum ionic vibrations superconducting materialsattracting vibrational superconducting properties quantum anharmonic ionic vibrations classical harmonic approximationinclusion compressed stannane p mmc phase
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Release of the English Version of China's Standards for Drinking Water Quality:Bridging Evidence and Global Health Equity 认领 引用
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作者 Bixiong Ye Xiaoyuan Yao +1 位作者 Lan Zhang Xiaoming Shi 《China CDC weekly》 SCIE CSCD 2026年第30期954-958,共5页
To eliminate language barriers to international water cooperation,the official English language version of China's Standards for Drinking Water Quality(GB 5749-2022)was released in December 2025.Compiled under nat... To eliminate language barriers to international water cooperation,the official English language version of China's Standards for Drinking Water Quality(GB 5749-2022)was released in December 2025.Compiled under national translation specifications,this authoritative edition ensures accurate communication of content.A comparative analysis with international standards demonstrates that GB 5749-2022 balances global harmonization and localized adaptation in accordance with China's hydrogeological and public health conditions.The English version effectively eliminates technical ambiguities in transnational water projects and strengthens China's voice in global water governance.Nonetheless,challenges remain,including cross-lingual interpretations issues and gaps in the coverage of emerging contaminants such as per-and polyfluoroalkyl substances(PFAS).This article proposes optimizing interpretative documents,establishing dynamic updating mechanisms,constructing equitable cooperation platforms,and improving multi-dimensional evaluation systems.It aims to facilitate the global application of China's drinking water criteria,provide references for developing countries,and contribute to equitable global public health governance. 展开更多
关键词 global harmonization comparative analysis Global Health Equity translation specificationsthis accurate communication contenta English Version Drinking Water Quality Standards drinking water
Low-Threshold Topological Pumping in Toroidal Spin-1 Bose–Einstein Condensate 认领 引用
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作者 Xue-Ying Yang Peng Liu +3 位作者 Hui-Bo Hong Si-Lin Chen Juan Li Rui-Fang Dong 《Chinese Physics Letters》 SCIE EI CAS CSCD 2026年第4期48-55,共8页
Singular spin-nematic vortices are unique topological excitations in spin-orbit-coupled spin-1 Bose–Einstein condensates.However,dynamically generating them in harmonic traps requires excessive Raman coupling to over... Singular spin-nematic vortices are unique topological excitations in spin-orbit-coupled spin-1 Bose–Einstein condensates.However,dynamically generating them in harmonic traps requires excessive Raman coupling to overcome the high energy cost of creating a density-depleted core.We demonstrate that a toroidal trapping potential naturally resolves this geometric mismatch.By accommodating the vortex core,the toroidal geometry lowers the formation threshold by∼50%and significantly broadens the stable phase boundary. 展开更多
关键词 harmonic traps spin orbit coupled broadens stable phase boundar singular spin nematic vortices low threshold topological pumping toroidal trapping potential excessive raman coupling formation threshold
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Permeance-harmonic-oriented Design and Optimization of a Field-modulated PM Hub Motor for High Torque Density 认领 引用
18
作者 Yuting Zhou Zixuan Xiang +3 位作者 Xiaoyong Zhu Qian Liu Deyang Fan Kunhua Chen 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2026年第2期176-187,共12页
This paper investigates an aggregated design and optimization method for permanent magnet hub(PMH)motors,guided by permeance harmonics,to meet low-speed,high-torque requirements.The key lies in establishing the correl... This paper investigates an aggregated design and optimization method for permanent magnet hub(PMH)motors,guided by permeance harmonics,to meet low-speed,high-torque requirements.The key lies in establishing the correlation between stator and rotor permeance harmonics and torque.Firstly,contribution equations describing the influence of stator and rotor permeance harmonics on torque are derived.It reveals that the contribution degree is affected by harmonic amplitude and phase.Then,the selection criteria for stator and rotor topology are formulated.The amplitude and phase characteristics of the permeance harmonic group are considered in criteria,which aim to achieve the aggregated design from a permeance harmonic perspective.Furthermore,based on the identified aggregated permeance harmonics,the airgap flux density harmonics directly linked to permeance harmonics are determined.Taking these harmonics as the goal,they are involved in the optimization process for high torque density.Sensitivity analysis and response surface analysis are adopted,respectively,to lock the design variables and their parameter ranges.Then,the motor topology with characteristics of high torque density is obtained through multi-objective optimization.Finally,a prototype experiment is conducted on the optimized PMH motor. 展开更多
关键词 Permanent magnet hub(PMH)motor torque density harmonic characteristic
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Numerical Simulation of Heat Transfer Enhancement by Vibration of an Irregular Pipe 认领 引用
19
作者 Riyi Lin Bi Pang Xinwei Wang 《Frontiers in Heat and Mass Transfer》 EI CAS 2026年第2期16-42,共27页
The thickening of condensed liquid film outside heat-exchange pipes and the pipe bundle effect can significantly degrade the heat transfer efficiency,thus restricting the vacuum phase-change heating furnace from achie... The thickening of condensed liquid film outside heat-exchange pipes and the pipe bundle effect can significantly degrade the heat transfer efficiency,thus restricting the vacuum phase-change heating furnace from achieving its rated thermal efficiency of over 90%.In this work,a heat transfer enhancement method coupling simple harmonic vibration with non-circular pipes was proposed.A CFD model describing the heat transfer process of horizontal pipes under vibratory conditions was established and stepwise validated against experimental data from published literature and the Nusselt analytical solution.Taking a 50 mm steel circular pipe as the reference,numerical simulations were performed to investigate the effects of structural parameters of oval and droplet-shaped pipes on the near-wall velocity,temperature,wall shear stress,and heat transfer coefficient under horizontal simple harmonic vibration.The results demonstrate that simple harmonic vibration can induce oblique cross-flow outside the pipes,enhance flow field disturbance,and disrupt the liquid film stability,thereby providing a crucial flow field regulation mechanism for vibration-enhanced external condensation heat transfer.An increase in the aspect ratio of dropletshaped pipes intensifies the wall contraction effect,promotes the formation of continuous small-scale vortices near the pipe wall,and significantly improves the time-averaged heat transfer coefficient.The heat transfer performance of oval pipes is slightly superior to that of circular pipes;among them,oval pipe 2 achieves a dynamic balance between shear driving force and liquid film resistance through the synergistic matching of velocity,temperature,and viscosity,thus exhibiting the optimal wall shear stress among the oval pipe series.Under dynamic conditions,the time-averaged heat transfer coefficients of non-circular pipes are consistently higher than those of circular pipes.Moreover,the inconsistency between the heat transfer coefficient and wall shear stress distributions reveals the multimechanism synergy characteristics of external condensation heat transfer on non-circular pipes.This study provides core theoretical support for the engineering design of vibration-enhanced heat transfer technologies in vacuum phase-change heating furnaces. 展开更多
关键词 Condensate film harmonic vibration shear force non-circular pipe heat transfer coefficient
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Improved Three-Vector Model Predictive Current Control Strategy for Fixed Switching Frequency on a Grid-Connected Inverter 认领 引用
20
作者 Hongsheng Su Dan Li Yuwei Du 《Energy Engineering》 EI 2026年第5期401-415,共15页
When the three-phase grid-connected inverter system is in operation,there are problems of significant switching losses and power losses.At the same time,if the switching frequency is not fixed,it will lead to problems... When the three-phase grid-connected inverter system is in operation,there are problems of significant switching losses and power losses.At the same time,if the switching frequency is not fixed,it will lead to problems such as a high content of low-order harmonics in the current on the grid side.This paper takes the three-phase grid-connected inverter as the research object and proposes a solution.Establish a mathematical model for the inverter system and analyze the transformation relationships of relevant electrical quantities across different coordinate systems.First,the paper proposes an improved three-vector model predictive current control algorithm.It employs an orthogonal-axis current zero-crossing method to calculate vector action times,enabling rapid and efficient determination of the desired sector.Then,based on this,an optimized switching sequence method is proposed.It fixes the switching frequency by adding a constraint term to the objective function.Finally,the effectiveness of the proposed method was validated through simulation and experimental results.The results demonstrate that the proposed control strategy optimizes the switching sequence and achieves fixed switching frequency control.It can effectively reduce switching losses and power losses,thereby lowering the harmonic content in the grid-connected side current.At the same time,the grid-connected current exhibits low harmonic content and minimal current ripple.Concurrently,the grid-connected current exhibits low harmonic content and minimal current ripple.Under dynamic conditions,it maintains high current tracking accuracy and demonstrates strong system robustness. 展开更多
关键词 Photovoltaic grid-connected system inverter model predictive control switching frequency harmonic analysis
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