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Journal of materials Science & Technology 2013年第12期29卷 1116-1122页

作者： Z.A.luo G.m.Xie Z.Y.ma G.l.Wang G.D.Wang State Key laboratory of Rolling and Automation Northeastern University Shenyang National laboratory for materials Science Institute of Metal ResearchChinese Academy of Sciences

As-extruded ZK60 and ZK60-Y magnesium alloy plates were successfully processed via friction stir processing （FSP） at a tool rotation rate of 1600 r/rain and a traverse speed of 200 mm/min. FSP resulted in the formation of equiaxed recrystallized microstructures with the average grain sizes of ,-8.5 and -4.7 μm in the ZK60 and ZK60-Y alloys, respectively. moreover, FSP broke and dispersed the mgZn2 and W-phase （mg3Zn3Y2） particles and dissolved mgZn2 phase in the FSP ZK60 alloy. With the addition of rare earth element yttrium （Y） into the ZK60 alloy, the ratio of the high angle grain boundaries （HAGBs） in the FSP alloys increased from 64% to 90%, and a certain amount of twins appeared in the FSP ZK60-Y alloy. The maximum elongation of 1200% and optimum strain rate of 3 X 10-3 s-1 achieved at 450 °C in the FSP ZK60-Y alloy were substantially higher than those of the FSP ZK60 alloy. This is attributed to the fine grains with high ratio of HAGBs and the distribution of a large number of dispersed second phase particles with high thermal stability in the FSP ZK60-Y alloy. Grain boundary sliding was identified as the primary deformation mechanism in the FSP ZK60 and ZK60-Y alloys from the superplastic data analyses and surficial morphology observations.

关键词： magnesium alloy Friction stir processing Rare earth element microstructure Superplasticity

Influence of light pattern thickness on the manipulation of dielectric microparticles by optoelectronic tweezers

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Photonics Research 2022年第2期10卷 550-556页

作者： Shuailong Zhang mohamed Elsayed Ran Peng Yujie Chen Yanfeng Zhang Steven l.Neale Aaron R.Wheeler School of mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of TechnologyBeijing 100081China Department of Chemistry University of TorontoTorontoOntario M5S 3H6Canada Institute of Biomedical Engineering University of TorontoTorontoOntario M5S 3G9Canada Donnelly Centre for Cellular and Biomolecular Research University of TorontoTorontoOntario M5S 3E1Canada Department of marine Engineering Dalian Maritime UniversityDalian 116026China State Key laboratory of Optoelectronic materials and Technologies School of Electronics and Information TechnologySun Yat-sen UniversityGuangzhou 510275China James Watt School of Engineering University of GlasgowGlasgow G128QQUK

Optoelectronic tweezer(OET) is a useful optical micromanipulation technology that has been demonstrated for various applications in electrical engineering and most notably cell selection for biomedical engineering. In this work, we studied the use of light patterns with different shapes and thicknesses to manipulate dielectric microparticles with OET. It was demonstrated that the maximum velocities of the microparticles increase to a peak and then gradually decrease as the light pattern’s thickness increases. Numerical simulations were run to clarify the underlying physical mechanisms, and it was found that the observed phenomenon is due to the co-influence of horizontal and vertical dielectrophoresis forces related to the light pattern’s thickness. Further experiments were run on light patterns with different shapes and objects with different sizes and structures. The experimental results indicate that the physical mechanism elucidated in this research is an important one that applies to different light pattern shapes and different objects, which is useful for enabling users to optimize OET settings for future micromanipulation applications.

关键词： pattern dielectric light

Isolated Cu-Sn diatomic sites for enhanced electroreduction of CO_(2)to CO

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Nano Research 2023年第7期16卷 8729-8736页

作者： Wei liu Haoqiang li Pengfei Ou Jing mao lili Han Jun Song Jun luo Huolin l.Xin State Key laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Department of Physics and Astronomy University of CaliforniaIrvineCA 92697USA Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China School of materials Science and Engineering Tianjin Key Lab of Photoelectric Materials&DevicesTianjin University of TechnologyTianjin 300384China Department of mining and materials Engineering McGill UniversityMontreal H3A 0C5Canada Teaching and Analytical Instrumentation Center School of Materials Science and EngineeringTianjin UniversityTianjin 300072China

Electrochemical CO_(2)reduction reaction(CO_(2)RR)to high-value product,CO,not only provides a key feedstock for the wellestablished Fischer-Tropsch process but also mitigates the greenhouse ***,it suffers from sluggish reaction kinetics,competitive hydrogen evolution reaction,and low ***,we report non-precious Cu-Sn diatomic sites anchored on nitrogen-doped porous carbon(CuSn/NPC)as an efficient catalyst for CO_(2)RR to *** catalyst exhibits outstanding selectivity with CO Faradaic efficiency(FE)up to 99.1%,much higher than those of individual Cu(66.2%)and Sn(51.3%)single-atom ***,high stability is confirmed by consecutive 24 h electrolysis with high selectivity from CO_(2)to *** calculations reveal an obvious activation of CO_(2)with weakened C-O bonds and distorted CO_(2)configuration upon chemisorption on the CuSn/NPC *** is also suggested CuSn/NPC is more selective for the CO_(2)RR with dominant CO production during the electrolysis,rather than the competing hydrogen evolution reaction.

关键词： CO_(2)reduction reaction Cu-Sn active site CO product dual-atom electrocatalyst density functional theory(DFT)calculation

A long-Range Generalized Predictive Control Algorithm for a DFIG Based Wind Energy System

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IEEE/CAA Journal of Automatica Sinica 2019年第5期6卷 1209-1219页

作者： J.S.Solis-Chaves lucas l.Rodrigues C.m.Rocha-Osorio Alfeu J.Sguarezi Filho the Department of Energy Engineering at the Federal University of ABC-UFABC Santo AndreSPBrazil

This paper presents a new long-range generalized predictive controller in the synchronous reference frame for a wind energy system doubly-fed induction generator based. This controller uses the state space equations that consider the rotor current and voltage as state and control variables, to execute the predictive control action. Therefore, the model of the plant must be transformed into two discrete transference functions, by means of an auto-regressive moving average model, in order to attain a discrete and decoupled controller, which makes it possible to treat it as two independent single-input single-output systems instead of a magnetic coupled multiple-input multiple-output system. For achieving that, a direct power control strategy is used, based on the past and future rotor currents and voltages estimation. The algorithm evaluates the rotor current predictors for a defined prediction horizon and computes the new rotor voltages that must be injected to controlling the stator active and reactive powers. To evaluate the controller performance, some simulations were made using matlab/Simulink. Experimental tests were carried out with a small-scale prototype assuming normal operating conditions with constant and variable wind speed profiles. Finally, some conclusions respect to the dynamic performance of this new controller are summarized.

关键词： Direct power control doubly-fed induction generator flux oriented control generalized predictive control long-range predictive control wind energy systems

Impact of grain size,Pr3+ concentration and host composition on non-contact temperature sensing abilities of polyphosphate nano- and microcrystals

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Journal of Rare Earths 2019年第8期37卷 812-818,I0001页

作者： S.Gharouel l.marciniak A.lukowiak W.Strek K.Horchani-Naifer m.Férid Research Unit of Rare Earth materials National Research Center in Sciences of MaterialsB.P.95 Hammam-Lif2050Tunisia b Institute of Low Temperature and Structure ResearchPAS Okolna St. 50-422WroclawPoland

In this article,varied praseodymium polyphosphate hosts:mI(li,Na K)Pr(PO3)4 microcrystals and lila1-xPrx(PO3)4(x = 0.01 ^-1)nanocrystals were successfully synthesized by the flux method and the coprecipitation technique,*** size of stoichiometric nanocrystals of liPr(PO3)4 was tuned by the te mpe rature of thermal treatment in range of 35-145 *** order to dete rmine the most suitable material for the non-contact optical thermometric applications,the temperature sensing measurements were carried out by using luminescence intensity ratio(lIR)of emission bands corresponding to the ^3 P1→ ^3H5 and ^3P0→ ^3 H5 electronic transitions of Pr3+ ions into the 123-423 K temperature *** influence of the host material composition of mⅠ(li,Na,K)Pr(PO3)4 microcrystals on the sensitivity of luminescent thermometers was *** is found that the sensitivity of lithium praseodymium polyphosphate is the highest of all micropowders under ***,it is found that the nanocrystals reveal much higher relative sensitivity in respect to the microcrystalline *** highest sensitivity of lIR temperature sensing is found for liPr(PO3)4 nanocrystals(35 nm grain size)in the whole temperature range,reaching 0.283%/K at 164 *** impact of the average grain size on the sensitivity of lIR based thermometers of liPr(PO3)4 nanocrystals was *** is found that the reduction of the grain size from 145 to 35 nm results in the enhancement of the relative sensitivity from0.156 to 0.240%/K at 223 *** it is found that the high dopant concentration possesses favorable influence on the relative sensitivity of lila1-xPrx(PO3)4 nanocrystalline luminescent thermometers.

关键词： Pr^3+ Temperature sensing luminescence intensity ratio Temperature sensitivity Grain size Dopant concentration

Unexpected ecotone dynamics of a sand dune vegetation complex following water table decline

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Journal of Plant Ecology 2016年第1期9卷 40-50页

作者： Csaba Tölgyesi márta Zalatnai lászlóErdős Zoltán Bátori Nicole Rosemary Hupp lászlóKörmöczi Department of Ecology University of SzegedSzeged H-6726Hungary Wildlife Biology Program College of Forestry and ConservationUniversity of Montana32 Campus DriveMissoulaMontanaMT 59812USA

Aims Central Hungarian inland dune ranges harbor heterogeneous grassland vegetation with an extensive network of ecotones,arranged perpendicular to topography-driven hydrologic *** area suffers from severe aridification due to climate change and local anthropogenic factors,which have led to a dramatic decline of the water *** a result,groundwater is no longer reachable for lowlying plant communities;thus,we expect they are bound to undergo profound *** study investigates how the plant communities respond to this changing environment over time by monitoring ecotones,since they are frequently the hotspots of ecosystem *** monitored five ecotones along permanent belt transects for 15 years to characterize their dynamic response,and to identify the internal structural changes of the plant communities the ecotones *** Ecotones were delineated with the split moving window *** dynamics of two ecotone parameters,location and contrast,were analyzed with linear regression models incorporating two independent variables:study year as a measure of time since the loss of groundwater,and precipitation as a possible driver of interannual *** internal changes of the patches separated by the ecotones were analyzed using plant functional *** Findings Precipitation had no detectable effect on the ecotone descriptors,but study year influenced ecotones in an unusual *** position of the ecotones appeared to be very stable in time;their dynamics are stationary,not directional as we *** contrasts had clear tendencies;two ecotones disappeared,one new one was formed and two ecotones showed no *** internal changes of the patches over time were dramatic,showing a shift toward more xeric and more open plant assemblages in most stretches of the ***,the dynamic response of the vegetation was not patch expansion ***,but fusion ***,which profoundly restructured the vegetati

关键词： groundwater decline plant functional group sand dune vegetation split moving window stationary ecotone

Scale effect of circularly polarized luminescent signal of matter

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National Science Review 2023年第5期10卷 232-239页

作者： Siyu Sun Xiaolin li Chen Xu Yan li YongZhen Wu Ben l.Feringa He Tian Xiang ma Key laboratory for Advanced materials and Feringa Nobel Prize Scientist Joint Research Center Frontiers Science Center for Materiobiology and Dynamic ChemistrySchool of Chemistry and Molecular EngineeringEast China University of Science and Technology School of Physics East China University of Science and Technology Stratingh Institute for Chemistry and Zernike Institute for Advanced materials Faculty of Science and EngineeringUniversity of Groningen

Circularly polarized luminescence(CPl) is an important part in the research of modern luminescent materials and photoelectric ***,chiral molecules or chiral structures are the key factors to induce CPl spontaneous *** this study,a scale-effect model based on scalar theory was proposed to better understand the CPl signal of luminescent *** chiral structures being able to induce CPl,achiral ordered structures can also have a significant influence on CPl *** achiral structures are mainly reflected in the particle scale in micro-order or macro-order,*** CPl signal measured under most conditions depends on the scale of the ordered medium,and does not reflect the inherent chirality of the excited state of the luminescent *** kind of influence is difficult to be eliminated by simple and univers al strategies in *** the same time,it is found that the measurement entropy of CPl detection may be the key factor to determine the isotropy and anisotropy of the CPl *** discovery would bring new opportunities to the research of chiral luminescent *** strategy can also greatly reduce the development difficulty of CPl materials and show high application potential in biomedical,photoelectric information and other fields.

关键词： scale effect circularly polarized luminescent chirality quantum dots perovskite

Spectrophotometric determination of tranexamic acid using vanillin

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药学学报 2009年第2期44卷 175-180页

作者： F.m.A. Rind m.G.H. laghari A.H. memon U.R. mughal E Almani N. memon m.Y. Khuhawar m.l. maheshwari Faculty of Pharmacy University of Sindh Jamshoro Pakistan Institute of Chemistry Faculty of Natural Sciences University of Sindh Jamshoro Pakistan

A new spectrophotometric method has been examined for the determination of the tranexamic acid (TA) by derivatization with vanillin (VAN). The molar absorptivity of TA was calculated 25 160 l·mol-1·cm-1 at λmax 354 nm and obeyed the Beer's law within 0.5-2.5 μg·ml-1. The color reaction was highly stable and did not show any change in absorbance up to 24 h. The method was applied for the analysis of TA from capsules, injections and tooth pastes. The amounts of TA found in capsules, injections and tooth pastes of various pharmaceutical companies were observed with 249.0-250.9 mg/capsule, 249.3-250.7 mg/injection and 0.048%-0.049% in tooth pastes with relative standard deviation (RSD) 0.2%-5.0% (n = 3).

关键词：分光方法氨甲环酸显色反应药物化学

A Quantitative Analysis of mn Segregation at Partitioned Ferrite/Austenite Interface in a Fe-C-mn-Si Alloy

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Journal of materials Science & Technology 2009年第3期25卷 383-388页

作者： H. Guo S.W. Yang C.J.Shang X.m. Wang X.l. He Department of materials Physics and Chemistry University of Science and Technology Beijing Beijing 100083 China

mn segregation at austenite/ferrite interface is studied in a Fe-C-mn-Si alloy held at 656°C. mn is partitioned during the growth of ferrite and as a result, a mn pile-up exists in front of interface on the matrix side. An approach to evaluate mn segregation quantitatively is developed by combining STEm raster window scanning and simulation of the interaction of the electron beam with the sample to subtract the contribution of mn pile-up and obtain pure mn segregation value. The evaluated maximum mn interfacial segregation is in the order of a half-monolayer. Printed by Copyright ©.

关键词： Interfacial segregation Phase transformation STEm Beam broadening

Nonlinear optical trapping effect with reverse saturable absorption

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Advanced Photonics 2023年第4期5卷 66-73页

作者： Zheng Zhu Yuquan Zhang Shuoshuo Zhang Aurele J.l.Adam Changjun min Hendrik Paul Urbach Xiaocong Yuan Shenzhen University Institute of Microscale Optoelectronics and State Key Laboratory of Radio Frequency Heterogeneous IntegrationNanophotonics Research CenterShenzhenChina Research Institute of Intelligent Sensing Research Center for Humanoid SensingZhejiang LabHangzhouChina Delft University of Technology Optics Research GroupDelftThe Netherlands

Nonlinear responses of nanoparticles induce enlightening phenomena in optical tweezers. With thegradual increase in optical intensity, effects from saturable absorption (SA) and reverse SA (RSA) arise insequence and thereby modulate the nonlinear properties of materials. In current nonlinear optical traps,however, the underlying physical mechanism is mainly confined within the SA regime because thresholdvalues required to excite the RSA regime are extremely high. Herein, we demonstrate, both in theory andexperiment, nonlinear optical tweezing within the RSA regime, proving that a fascinating composite trappingstate is achievable at ultrahigh intensities through an optical force reversal induced through nonlinearabsorption. Integrated results help in perfecting the nonlinear optical trapping system, thereby providingbeneficial guidance for wider applications of nonlinear optics.

关键词： nonlinear optical tweezers optical force reverse saturable absorption