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A Review of State-of-the-art Flexible Power Point Tracking Algorithms in Photovoltaic Systems for Grid Support:Classification and Application

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 1-21页

作者： Mina Haghighat Mehdi Niroomand Hossein Dehghani Tafti Christopher D.townsend Tyrone Fernando the Department of Electrical Engineering University of IsfahanIsfahanIran the Department of Electrical Electronic and Computer EngineeringUniversity of Western AustraliaCrawley WA 6009Australia

To maximize conversion efficiency,photovoltaic(PV)systems generally operate in the maximum power point tracking(MPPT)***,due to the increasing penetra tion level of PV systems,there is a need for more developed control functions in terms of frequency support services and voltage control to maintain the reliability and stability of the power ***,flexible active power control is a manda tory task for grid-connected PV systems to meet part of the grid ***,a significant number of flexible pow er point tracking(FPPT)algorithms have been introduced in the existing *** purpose of such algorithms is to real ize a cost-effective method to provide grid support functional ities while minimizing the reliance on energy storage *** paper provides a comprehensive overview of grid support functionalities that can be obtained with the FPPT control of PV systems such as frequency support and volt-var *** of these grid support functionalities necessitates PV sys tems to operate under one of the three control strategies,which can be provided with FPPT *** three control strate gies are classified as:①constant power generation control(CP GC),②power reserve control(PRC),and③power ramp rate control(PRRC).A detailed discussion on available FPPT algo rithms for each control strategy is also *** paper can serve as a comprehensive review of the state-of-the-art FPPT algorithms that can equip PV systems with various grid support functionalities.

关键词： Maximum power point tracking(MPPT) flexi ble power point tracking(FPPT) power reserve control(PRC) power ramp rate control(PRRC) low voltage ride-through(LVRT) constant power generation(CPG)

搭桥还是修路？——PCI Express显卡接口之争的最新消息

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微型计算机 2004年第10期24卷 25-27页

作者： ice

尽管还没有实际的产品出现，但NVIDIA和ATI的PCI Express显卡接口之争已炒得沸沸扬扬。我们专门收集整理了到截稿为止的关于PCI Express显卡接口之争的最新消息，仅供读者参考，并不保证消息的准确性。

关键词： PCI Express显卡接口问题搭桥 NVIDIA公司 HSI技术 ATI公司原生解决方案

CONTINUOUS AND DISCRETE N-CONVEX APPROXIMATIONS

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Analysis in Theory and Applications 1992年第4期8卷 28-34页

作者： D.Legg D.townsend Indiana University-Purdue University U.S.A

We show that the best L_p-approximant to continuous functions by n-convex functions is the limit of discrete n-convex *** techniques of the proof are then used to show the existence of near interpolants to discrete n-... 详细信息

关键词： CONTINUOUS AND DISCRETE N-CONVEX APPROXIMATIONS

The corner that held them

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The corner that held them

Quantifying foliar trait variation and covariation in sun and shade leaves using leaf spectroscopy in eastern North America

作者： Sylvia townsend Warner

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Forest Ecosystems 2024年第5期11卷 728-742页

作者： Zhihui Wang Philip A.townsend Eric L.Kruger Anna K.Schweiger Guangdong Provincial Key Laboratory of Remote Sensing and Geographical Information System Guangdong Open Laboratory of Geospatial Information Technology and ApplicationGuangzhou Institute of GeographyGuangdong Academy of SciencesGuangzhou510070China Department of Forest and Wildlife Ecology University of Wisconsin-Madison1630 Linden DriveMadisonWI53706USA Department of Land Resources and Environmental Sciences Montana State University334 Leon Johnson HallBozemanMT59717USA

Characterizing foliar trait variation in sun and shade leaves can provide insights into inter-and intra-species resource use strategies and plant response to environmental ***,datasets with records of multiple foliar traits from the same individual and including shade leaves are sparse,which limits our ability to investigate trait-trait,trait-environment relationships and trait coordination in both sun and shade *** presented a comprehensive dataset of 15 foliar traits from sun and shade leaves sampled with leaf spectroscopy,including 424 individuals of 110 plant species from 19 sites across eastern North *** investigated trait variation,covariation,scaling relationships with leaf mass,and the effects of environment,canopy position,and taxonomy on trait ***,sun leaves had higher leaf mass per area,nonstructural carbohydrates and total phenolics,lower mass-based chlorophyll a+b,carotenoids,phosphorus,and potassium,but exhibited species-specific *** between sun and shade leaf traits,and trait-environment relationships were overall consistent across *** main dimensions of foliar trait variation in seed plants were revealed including leaf economics traits,photosynthetic pigments,defense,and structural *** and canopy position collectively explained most of the foliar trait *** study highlights the importance of including intra-individual and intra-specific trait variation to improve our understanding of ecosystem *** findings have implications for efficient field sampling,and trait mapping with remote sensing.

关键词： Foliar traits Leaf trait variation Trait-environment covariation Shade leaves NEON Leaf spectroscopy

Bridge vibration under complex wind field and corresponding measurements: A review

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Journal of Traffic and Transportation Engineering(English Edition) 2022年第3期9卷 339-362页

作者： Enbo Yu Guoji Xu Yan Han Peng Hu Jamie F.townsend Yongle Li School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China School of Civil Engineering Changsha University of Science and TechnologyChangsha 410114China

Due to increased demands in transportation development,bridge construction has been extended to areas with complex wind *** addition to common flow features such as high wind speeds and strong turbulence intensity,in coastal areas,bridges are likely to be exposed to non-stationary and non-Gaussian high-speed wind fields during hurricane *** built in mountainous regions will experience varying wind directions,incident angles of attack(AOA),and wind speed variation due to undulating *** complex wind fields are challenging to the bridge engineering community to which accurate calculation methods and suppression measures for bridge vibration are urgently *** this paper,state-of-the-art research results are introduced through three categories:(a)the distinctive characteristics of complex wind fields in offshore and mountainous areas,(b)the categories of wind-induced vibrations for bridges,and(c)the suppression measures employed in engineering *** now,the studies regarding the coupled bridge vibration in complex wind fields have made considerable progress,but a richer database of actual wind measurement results and more efficient simulation methods still need to be further established.

关键词： Complex wind field Long-span bridge Vibration suppression Buffeting VIV Flutter

Improving diabetic and hypertensive retinopathy with a medical food containing L-methylfolate: a preliminary report

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Eye and Vision 2019年第1期6卷 164-174页

作者： Jianhua Wang Craig Brown Ce Shi Justin townsend Giovana Rosa Gameiro Peng Wang Hong Jiang Bascom Palmer Eye Institute University of MiamiMiller School of Medicine1638 NW 10th AvenueMcKnight Building-Room 202AMiamiFL 33136USA Department of Ophthalmology College of MedicineUniversity of Arkansas for Medical SciencesFayettevilleARUSA School of Ophthalmology and Optometry Wenzhou Medical UniversityWenzhouZhejiangChina Department of Ophthalmology Shanghai General HospitalShanghai Jiaotong University School of MedicineShanghaiChina

Background:Homocysteine and vitamin D may play a role in the development of diabetic and hypertensive retinopathy in patients with diabetes mellitus(DM)and *** food with L-methylfolate and vitamin D theoretically may improve diabetic and hypertensive retinopathy,however,the outcome of these nutritional approaches has not been fully examined.A retrospective case review was done of cases of retinopathy reversal in patients on Ocufolin^(TM) and a similar nonprescription multivitamin,Eyefolate^(TM).In this study,they were administered L-methylfolate(2.7 mg and 3.0 mg,respectively)and vitamin D3(4500 IU each).These dosages are significantly above the RDA but well below levels associated with *** presentation:Seven patients had nonproliferative diabetic retinopathy(NPDR)and some of them had *** patient had only hypertensive *** patients were instructed to take Ocufolin^(TM)medical food as a food *** genetic testing for MTHFR polymorphisms was *** photography was used to document the fundus condition of the enrolled eyes in 8 NPDR patients at the initial and follow-up ***(MA)and exudates were observed to be improved in some trial *** subjects had one or more MTHFR *** had diabetic retinopathy,hypertensive retinopathy,or *** were resolved,and exudates were decreased in 8/8 cases after taking the medical *** edema was found in 2/8 cases and improved or resolved in both cases after taking the medical food or the *** best corrected visual activity was stable or improved in 8/8 ***:We report a series of diabetic and hypertensive retinopathy cases with MTHFR polymorphisms and the improvement of retinal microvasculature(mainly MAs)in serial fundus photography after taking a medical food or supplement containing L-methylfolate and vitamin *** appears that the use of nutritional supplements and medical foods containin

关键词： Diabetes Homocysteine L-methylfolate Microaneurysms MTHFR C677T Retinopathy Vitamin D