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Asymptotic Tracking Control for Wind Turbines in Variable Speed Mode

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IEEE/CAA Journal of Automatica Sinica 2017年第3期4卷 569-576页

作者： wei Lin Zongtao Lu wei wei Dongguan University of Technology Dongguan 523808China Department of Electrical Engineering and Computer Science Case Western Reserve University

This paper presents a variable speed control strategy for wind turbines in order to capture maximum wind *** turbines are modeled as a two-mass drive-train system with generator torque *** on the obtained wind turbine model,variable speed control schemes are *** tracking controllers are designed to achieve asymptotic tracking for a prescribed rotor speed reference signal so as to yield maximum wind power *** to the difficulty of torsional angle measurement,an observer-based control scheme that uses only rotor speed information is further developed for global asymptotic output *** effectiveness of the proposed control methods is illustrated by simulation results.

关键词： Asymptotic tracking partial-state and output feedback two-mass drive-train model variable speed control wind turbines

Experimental Investigation of Effects of Distributed Riblets on Aerodynamic Performance of a Low-speed Compressor

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Journal of Thermal Science 2013年第6期22卷 592-599页

作者： MA Hongwei wei wei National Key Laboratory of Science and Technology on Aero-Engines School of Energy and Power EngineeringBeihang University

It is well known that riblet applied on compressor blades is a promising flow control technique. However, detailed investigation of its effects on the flow field of turbomachinery is rare in existing literatures. This paper presents a detailed experimental investigation of effects of distributed riblet on the flow field of an axial compressor iso- lated-rotor stage. The research was performed in a large-scale facility respectively with two configurations, in- eluding grooved hub, and grooved surface on both hub and partial suction surface. The riblet film is rectangle grooved type with a height of 0.1 ram. The flow field at 10% chord downstream from the cascade trailing edge was measured using a mini five-hole pressure probe and a total pressure probe. The testing was conducted at sev- eral operational points under two reduced rotational speeds. Stagnation pressure loss in rotational frame was cal- culated and compared with the control test in which a smooth film was applied to the corresponding position. Results show that with the grooved hub configuration at the design operation point of the lower rotational speed, the riblet film provides an obvious improvement of a 48% reduction of total pressure loss in rotational frame. Also, a distinct weaken hub comer vortex was identified. In the meantime, there exists a deviation of flow angle about 5 degrees at 20%-80% span which previously was not considered to be the affected region.

关键词： distributed riblet large-scale compressor hub corner vortex loss reduction.

Experimental evidence for the mechanism of subcritical vortex-induced vibration

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Journal of Hydrodynamics 2023年第1期35卷 17-26页

作者： Zhen Lyu wei-wei Zhang School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China

The vortex-induced vibration(VIV)of circle cylinder can occur at subcritical Reynolds numbers as low as 20,which is called subcritical *** numerical research suggests that the interaction of fluid mode and structural mode is the primary cause of its *** to the limitations of experimental techniques and data analysis methods,researchers failed to find experimental evidence to support this *** this end,we conducted subcritical VIV tests in a rotating channel and discovered that the flow is unstable when subcritical VIV ***,an experimental data-driven model for unsteady flow is *** coupling the unsteady flow model with the structural dynamic equations,we constructed the FSI model for subcritical *** performing linear stability analysis on the FSI model,we found that there are two key modes in the FSI system,namely fluid mode and structural *** two modes will couple when the structural natural frequency is close to the characteristic frequency of the flow,resulting in the instability of structural mode and thus inducing subcritical *** experimental finding clarifies that subcritical VIV is essentially flutter as a result of structural mode instability,providing the first experimental evidence for the mechanism of subcritical VIV.

关键词： Vortex-induced vibration(VIV) fluid mode reduced-order model experimental data-driven modelling

Recent advances in platelet engineering for anti-cancer therapies

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Particuology 2022年第5期20卷 2-13页

作者： Yanlin Lv wei wei Guanghui Ma State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

Platelets contribute a major role in hemostasis by clumping and coagulation at the site of blood vessel *** light of recent findings of a close relationship between platelets and immunological response,as well as interactions between platelets and cancer cells,novel engineering strategies have emerged for the integration of platelets or platelet membrane(PM)with anti-cancer *** this review,we discuss several recent innovations that use platelets or their membranes to circumvent host immune responses and target tumor cells with high specificity to deliver a range of pharmacological,photothermal,or immunologic agents for eradication of recalcitrant tumor *** specifically,we compare the relative advantages of using whole platelets versus single or hybrid PM to coat nanoparticle *** cargoes range from well-established anti-tumor apoptosis-inducing agents,to relatively new photothermal agents that can induce a feedback cascade in which they induce vascular damage to the tumor which recruits more platelet-or membrane-encapsulated agents to induce further *** also discuss the use of engineered platelets to produce programmed cell death-inducing platelet derived *** review provides an overview and future directions for this promising platelet-based biomimetic approach to anti-cancer therapy.

关键词： Engineering platelets Platelet-mimicking Drug delivery Anti-cancer therapy

A low-frequency and broadband wave-insulating vibration isolator based on plate-shaped metastructures

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1171-1188页

作者： wei wei Feng GUAN Xin FANG College of Intelligent Science National University of Defense TechnologyChangsha410073China Naval Research Academy Beijing100161China

A metamaterial vibration isolator,termed as wave-insulating isolator,is proposed,which preserves enough load-bearing capability and offers ultra-low and broad bandgaps for greatly enhanced wave *** consists of plate-shaped metacells,whose symmetric and antisymmetric local resonant modes offer several low and broad mode bandgaps although the complete bandgap remains high and *** bandgap mechanisms,vibration isolation properties,effects of key parameters,and robustness to complex conditions are *** experimentally demonstrated,the wave-insulating isolator can improve the vibration insulation in the ranges of[50 Hz,180 Hz]and[260 Hz,400 Hz]by 15 dB and 25 dB,respectively,in contrast to the conventional isolator with the same first resonant frequency.

关键词： metamaterial and metastructure vibration isolation bandgap wave insulation plate

Evaluation of Ni-Fe base alloys as inert anode for low-temperature aluminium electrolysis

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Journal of Materials Science & Technology 2022年第12期107卷 216-226页

作者： wei wei Shujiang Geng Fuhui Wang Shenyang National Laboratory for Materials Science Northeastern UniversityNo.3-11 Wenhua RoadShenyang 110819China

Isothermal oxidation behaviors of Ni–Fe(wt.%)and of the same alloy with additions of 10 and 15%Cr alloys in the air at 800℃and 900℃and their anodic behaviors in aluminum electrolysis system at 800℃were *** composition morphologies of oxide scales were characterized by XRD,SEM,and *** show that the scales formed on Ni–Fe alloy at both temperatures consisted of an inner(Ni,Fe)Olayer and an outer *** Ni–Fe–10Cr alloy,an external(Ni,Fe)O/FeOlayers and an internal oxidation zone were formed at 800°C,while a continuous CrOlayer forms at the internal oxidation zone/substrate interface at 900°C.A multilayer structure oxide of CrO/(Ni,Fe,Cr)O/(Ni,Fe)O/FeOwas formed on Ni–Fe–15Cr alloy at 800°C,while at 900℃the FeObecomes discontinuous disperses in the(Ni,Fe)Olayer close to the *** in oxidation temperature or Cr content for Ni–Fe–Cr alloys promote the growth of the inner CrOlayer and simultaneously reduce *** 4 h of electrolysis at an anode current density of 0.25 A cm,the oxidation resistance of Ni–Fe–15Cr anode is superior to the Ni–Fe anode.

关键词： Alloy Inert anodes Selective oxidation High temperature corrosion

Lag times in toe-to-heel air injection(THAI)operations explain underlying heavy oil production mechanisms

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Petroleum Science 2022年第3期19卷 1165-1173页

作者： wei wei Ian D.Gates Department of Chemical and Petroleum Engineering University of CalgaryCalgaryAlbertaCanada

From a time value of revenue point of view,it is preferred that the time between reservoir stimulation and oil production response is *** oil combustion processes have a lag time between air injection and liquid production,but the common practice in production data analysis uses simultaneous injection and production data when seeking a relationship between *** this research,the time scales of production for the Kerrobert toe-to-heel air injection(THAI)heavy oil project in Saskatchewan,Canada,is analyzed by using cross correlation analysis,*** delay analysis between air injection and oil *** results reveal two time scales with respect to production response with two distinctive recovery mechanisms:(1)a short time scale response(nearly instantaneous)where oil production peaks right after air injection(directly after opening production well)reflecting cold heavy oil production mechanisms,and(2)a longer time scale(of order of 100-300 days)response where peak production occurs associated with the collective phenomena of air injection,heat generating reactions,heat transfer,and finally,heated mobilized heavy oil drainage to the production *** understanding of the two time scales and associated production mechanisms provides a basis for improving the performance of THAI.

关键词： Heavy oil In situ combustion Toe-to-heel air injection(THAI) Production analysis Lag time

Enabling a stable and dendrite-suppressed Zn anode via facile surface roughness engineering

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Journal of Materials Science & Technology 2022年第7期102卷 272-277页

作者： Jinghao Li Kehan Le wei wei State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China International School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

The safety and cycle lifespan of zinc metal-based aqueous batteries are greatly restricted by zinc *** poor cycling performance of zinc metal anode is often considered to be impacted by the dendrite growth,surface passivation,zinc metal corrosion and hydrogen evolution reaction,while surface roughness is a matter that has often been ignored in past ***,a roughness gradient is constructed on the zinc anode surface by a simple grinding and pasting *** has been found the modified zinc anodes with lower surface roughness exhibit the smaller zinc deposition overpotential and longer cycle ***,in situ optical microscopy photographs indicate that the zinc anode with an optimized roughness enables more uniform distribution of zinc precipitation and corrosion sites,which will facilitate a stable cycling performance of aqueous zinc ion *** Zn anode dendrite-suppressing mechanism via surface roughness engineering was revealed through finite element computational *** results emphasize the effectiveness of roughness engineering for tuning the surface physics of Zn anode and provide a facile strategy to develop better and safer aqueous zinc ion batteries.

关键词： Surface roughness Zn metal anode Surface engineering Aqueous zinc-ion batteries

Organic conjugated polymers and polymer dots as photocatalysts for hydrogen production

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Frontiers in Energy 2021年第3期15卷 667-677页

作者： Saket MATHUR Benjamin ROGERS wei wei Mechanical Engineering Department Wichita State UniversityWichita KS 67260USA

Owing to the outstanding characteristics of tailorable electronic and optical properties,semiconducting polymers have attracted considerable attention in recent *** them,organic polymer dots process large breadth of potential synthetic diversity are the representative of photocatalysts for hydrogen production,which presents both an opportunity and a *** this mini-review,first,the organic polymer photocatalysts were ***,recent reports on polymer dots which showed a superior photocatalytic activity and a robust stability under visible-light irradiation,for hydrogen production were ***,challenges and outlook on using organic polymer dots-based photocatalysts from hydrogen production were discussed.

关键词： polymer dots(Pdots) photocatalysis hydrogen production