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Thin ceramic PZT dual-and multi-frequency pMUT arrays for photoacoustic imaging

Microsystems & Nanoengineering 2022年第6期8卷 23-34页

作者： Qincheng Zheng Haoran Wang Hao Yang Huabei Jiang Zhenfang Chen Yao lu philip X.-l.Feng Huikai Xie School of Integrated Circuits and Electronics Beijing Institute of Technology(BIT)100081 BeijingChina Department of Electrical and Computer Engineering University of FloridaGainesvilleFL 32611USA Department of Medical Engineering University of South FloridaTampaFL 33620USA MEMS Engineering and Materials Inc. SunnyvaleCA 94086USA BIT Chongqing Institute of Microelectronics and Microsystems 400030 ChongqingChina

Miniaturized ultrasonic transducer arrays with multiple frequencies are key components in endoscopic photoacoustic imaging(PAI)systems to achieve high spatial resolution and large imaging depth for biomedical *** this article,we report on the development of ceramic thin-film PZT-based dual-and multi-frequency piezoelectric micromachined ultrasonic transducer(pMUT)arrays and the demonstration of their PAI *** chips sized 3.5mm in length or 10mm in diameter,square and ring-shaped pMUT arrays incorporating as many as 2520 pMUT elements and multiple frequencies ranging from 1 MHz to 8 MHz were developed for endoscopic PAI *** ceramic PZT with a thickness of 9μm was obtained by wafer bonding and chemical mechanical polishing(CMP)techniques and employed as the piezoelectric layer of the pMUT arrays,whose piezoelectric constant d_(31)was measured to be as high as 140 pm/*** from this high piezoelectric constant,the fabricated pMUT arrays exhibited high electromechanical coupling coefficients and large vibration *** addition to electrical,mechanical,and acoustic characterization,PAI experiments with pencil leads embedded into an agar phantom were conducted with the fabricated dual-and multi-frequency pMUT *** signals were successfully detected by pMUT elements with different frequencies and used to reconstruct single and fused photoacoustic images,which clearly demonstrated the advantages of using dual-and multi-frequency pMUT arrays to provide comprehensive photoacoustic images with high spatial resolution and large signal-to-noise ratio simultaneously.

关键词： ceramic piezoelectric dual

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large-scale edge waves generated by a moving atmospheric pressure

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Theoretical & Applied Mechanics letters 2012年第4期2卷 13-16页

作者： Chao An philip l-F. liu Seung Nam Seo School of Civil and Environmental Engineering CorneU University Ithaca 14853 USA Coastal Engineering and Ocean Energy Research Department Korea Ocean Research and DevelopmentInstitute Seoul 426744 South Korea

long waves generated by a moving atmospheric pressure distribution, associated with a storm, in coastal region are investigated numerically. For simplicity the moving atmospheric pressure is assumed to be moving only in the alongshore direction and the beach slope is assumed to be a constant in the on-offshore direction. By solving the linear shallow water equations we obtain numerical solutions for a wide range of physical parameters, including storm size （2a）, storm speed （U）, and beach slope （a）. Based on the numerical results, it is determined that edge wave packets are generated if the storm speed is equal to or greater than the critical velocity, Ucr, which is defined as the phase speed of the fundamental edge wave mode whose wavelength is scaled by the width of the storm size. The length and the location of the positively moving edge wave packet is roughly Ut/2 〈 y 〈 Ut, where y is in the alongshore direction and t is the time. Once the edge wave packet is generated, the wavelength is the same as that of the fundamental edge wave mode corresponding to the storm speed and is independent of the storm size, which can, however, affect the wave amplitude. When the storm speed is less than the critical velocity, the primary surface signature is a depression directly correlated to the atmospheric pressure distribution.

关键词： edge wave packet moving atmospheric pressure linear and nonlinear shallow water waves,numerical solutions

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Selective excitation and imaging of ultraslow phonon polaritons in thin hexagonal boron nitride crystals

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light(Science & Applications) 2018年第1期7卷 808-816页

作者： Antonio Ambrosio Michele Tamagnone Kundan Chaudhary luis A.Jauregui philip Kim William l.Wilson Federico Capasso Center for Nanoscale Systems Harvard UniversityCambridgeMA 02138USA Department of Physics Harvard UniversityCambridgeMA 02138USA Harvard John A.Paulson School of Engineering and Applied Sciences Harvard UniversityCambridgeMA 02138USA

We selectively excite and study two new types of phonon-polariton guided modes that are found in hexagonal boron nitride thin flakes on a gold *** modes show substantially improved confinement and a group velocity that is hundreds of times slower than the speed of light,thereby providing a new way to create slow light in the midinfrared range with a simple structure that does not require *** mode is the fundamental mode in the first Restrahlen band of hexagonal boron nitride thin crystals on a gold substrate;the other mode is equivalent to the second mode of the second Restrahlen band of hexagonal boron nitride flakes that are suspended in *** new modes also couple efficiently with incident light at the hexagonal boron nitride edges,as we demonstrate experimentally using photo-induced force microscopy and scanning near-field optical *** high confinement of these modes allows for Purcell factors that are on the order of tens of thousands directly above boron nitride and a wide band,with new perspectives for enhanced light-matter *** findings demonstrate a new approach to engineering the dispersion of polaritons in 2D materials to improve confinement and light-matter interaction,thereby paving the way for new applications in mid-infrared nano-optics.

关键词： interaction. boron hexagonal

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Biomaterial and tissue-engineering strategies for the treatment of brain neurodegeneration

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Neural Regeneration Research 2022年第10期17卷 2108-2116页

作者： Bridget Martinez philip V.Peplow Department of Medicine St.Georges University School of MedicineGrenada Department of Anatomy University of OtagoDunedinNew Zealand

The incidence of neurodegenerative diseases is increasing due to changing age demographics and the incidence of sports-related traumatic brain injury is tending to increase over *** approved medicines for neurodegenerative diseases only temporarily reduce the symptoms but cannot cure or delay disease *** transplantation strategies offer an alternative approach to facilitating central nervous system repair,but efficacy is limited by low in vivo survival rates of cells that are injected in *** cells that are attached to or encapsulated within a suitable biomaterial construct has the advantage of enhancing cell survival in vivo.A variety of biomaterials have been used to make constructs in different types that included nanoparticles,nanotubes,microspheres,microscale fibrous scaffolds,as well as scaffolds made of gels and in the form of *** these,Tween 80-methoxy poly(ethylene glycol)-poly(lactic-co-glycolic acid)nanoparticles loaded with rhynchophylline had higher transport across a blood-brain barrier model and decreased cell death in an in vitro model of Alzheimer’s disease than rhynchophylline or untreated nanoparticles with *** an in vitro model of Parkinson’s disease,trans-activating transcriptor bioconjugated with zwitterionic polymer poly(2-methacryoyloxyethyl phosphorylcholine)and protein-based nanoparticles loaded with non-Fe hemin had a similar protective ability as free non-Fe hemin.A positive effect on neuron survival in several in vivo models of Parkinson’s disease was associated with the use of biomaterial constructs such as trans-activating transcriptor bioconjugated with zwitterionic polymer poly(2-methacryoyloxyethyl phosphorylcholine)and protein-based nanoparticles loaded with non-Fe hemin,carbon nanotubes with olfactory bulb stem cells,poly(lactic-co-glycolic acid)microspheres with attached DI-MIAMI cells,ventral midbrain neurons mixed with short fibers of poly-(l-lactic acid

关键词： Alzheimer’s disease biomaterial cell transplantation neurodegeneration neurodegenerative disease Parkinson’s disease tissue-engineering traumatic brain injury

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Productivity of well-watered Panicum virgatum does not increase with CO_(2) enrichment

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Journal of Plant Ecology 2012年第4期5卷 366-375页

作者： philip A.Fay H.Wayne Polley Virginia l.Jin Michael J.Aspinwall USDA-ARS Grassland Soil and Water Research laboratory 808 E Blackland RdTempleTX 76502USA USDA-ARS Agroecosystem Management Research 137 Keim HallUniversity of Nebraska-LincolnLincolnNE 68583USA Section of Integrative Biology 1 University StationC0930University of Texas at AustinAustinTX 78712USA

Aims Rising atmospheric CO_(2) has been shown to increase aboveground net primary productivity(ANPP)in water-limited perennial grasslands,in part by reducing stomatal conductance and transpiration,thereby reducing depletion of soil ***,the benefits of CO_(2) enrichment for ANPP will vary with soil type and may be reduced if water limitation is *** is known about CO_(2) effects on ANPP of Panicum virgatum,a perennial C4 tallgrass and potential bioenergy *** hypothesized that if water limitation is minimized,(i)CO_(2) enrichment would not increase *** ANPP because photosynthetic rates of this C4 grass would not increase and because decreased transpiration at elevated CO_(2) would provide little additional benefit in increased soil moisture and(ii)soil type will have little effect on *** CO_(2) responses because of high overall soil *** Growth and leaf physiology of *** cv.‘Alamo’were studied as plants established for 4 years on silty clay and clay soils along a 250 to 500 ll l-1 gradient in atmospheric CO_(2) located in central Texas,*** were watered to replace evapotranspiration,fertilized with NO_(3)NH_(4) and P_(2)O_(5) and clipped to standard height during *** Findings ANPP increased through the third year of *** moisture(0–20 cm),ANPP,tiller numbers and leaf area index were 8–18%higher on the clay than on the silty clay *** did not increase with CO_(2) except in the planting ***,biomass removed with clipping strongly increased with CO_(2) in years 2 and 3,suggesting that CO_(2) enrichment increased the early-to mid-season growth of establishing *** but not later regrowth or that of fully established ***,CO_(2) enrichment differentially affected two components of ANPP in years 2 and 3,increasing tiller mass and reducing tiller *** reallocation of resources in clipped *** suggested increased meristem limitation of productivi

关键词： switchgrass bioenergy resource allocation tillering meristem limitation

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The Changing Cold Regions Network:Observation,diagnosis and prediction of environmental change in the Saskatchewan and Mackenzie River Basins,Canada

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Science China Earth Sciences 2015年第1期58卷 46-60页

作者： Chris M DEBEER Howard S WHEATER William l QUINTON Sean K CAREY Ronald E STEWART Murray D MACKAY philip MARSH Global Institute for Water Security University of SaskatchewanNational Hydrology Research Centre Cold Regions Research Centre Wilfrid Laurier University School of Geography and Earth Sciences Mc Master University Department of Environment and Geography University of Manitoba Science and Technology Branch Environment Canada

Climate change is causing rapid and severe changes to many Earth systems and processes,with widespread cryospheric,ecological,and hydrological impacts globally,and especially in high northern *** is of major societal concern and there is an urgent need for improved understanding and predictive tools for environmental *** Changing Cold Regions Network(CCRN)is a Canadian research consortium with a focus to integrate existing and new experimental data with modelling and remote sensing products to understand,diagnose,and predict changing land,water,and climate,and their interactions and feedbacks over the geographic domain of the Mackenzie and Saskatchewan River Basins in *** network operates a set of 14 unique and focused Water,Ecosystem,Cryosphere and Climate(WECC)observatories within this region,which provide opportunities to observe and understand processes and their interaction,as well as develop and test numerical simulation models,and provide validation data for remote sensing *** paper describes this network and its observational,experimental,and modelling *** overview of many of the recent Earth system changes observed across the study region is provided,and some local insights from WECC observatories that may partly explain regional patterns and trends are *** of the model products being developed are discussed,and linkages with the local to international user community are reviewed—In particular,the use of WECC data towards model and remote sensing product calibration and validation is *** future activities and prospects for the network are also presented at the end of the paper.

关键词： climate change cryosphere hydrology atmospheric science ecology modelling Canada

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Guest Editorial for Special Issue on Human-centered Intelligent Robots:Issues and Challenges

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IEEE/CAA Journal of Automatica Sinica 2017年第4期4卷 599-601页

作者： Zhijun li C.l.philip Chen Wei He IEEE College of Automation Science and Engineering South China University of Technology Department of Computer and Information Science Faculty of Science and Technology University of Macao School of Automation and Electrical Engineering University of Science and Technology Beijing

The special issue aims to address a broad spectrum of topics ranging from human-centered intelligent robots acting as a servant,secretary,or companion to intelligent robotic *** special issue publishes original papers of innovative ideas and concepts,new discoveries,and novel applications and business models relevant to the field of human-centered intelligent *** this special issue,modeling,intelligent control,

关键词： In Guest Editorial for Special Issue on Human-centered Intelligent Robots:Issues and Challenges

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Neural Network Based Adaptive Backstepping Tracking Control for Accommodation Vessel 36

Neural Network Based Adaptive Backstepping Tracking Control ...

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第36届中国控制会议

作者： Guoxing Wen C.l.philip Chen Ning Zhou Zhao Xu Department of mathematics Binzhou University Department of Computer and Information Science Faculty of Science and TechnologyUniversity of Macau Dalian Maritime University College of Computer and Information Sciences Fujian Agriculture and Forestry University School of Electronics and Information Northwestern Polytechnical University

ISBN: (纸本)9781538629185

Combined with the backstepping technique,a neural network(NN)-based adaptive tracking control scheme is proposed for the Accommodation Vessel(AV).The control objective is to steer AV following the trajectory of Floating Production Storage and Offloading(FPSO) and keeping the desired distance with FPSO so that the smooth gangway operation can be *** order to fulfill the control task,backstepping is used to achieve the tracking of trajectory;adaptive neural network is used to approximate the unknown nonlinear dynamic of AV for controller ***,it is proven that the proposed control approach can guarantee AV following to *** simulation results further demonstrate effectiveness of the proposed method.

关键词： Adaptive tracking control Backstepping Neural network Accommodation Vessel

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Inhibition of vascular adhesion protein-1 modifies hepatic steatosis in vitro and in vivo

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World Journal of Hepatology 2020年第11期12卷 931-948页

作者： Emma l Shepherd Sumera Karim philip N Newsome Patricia F lalor Centre for liver and Gastroenterology Research Birmingham National Institute for Health ResearchBirmingham Biomedical Research CentreInstitute of Immunology and ImmunotherapyUniversity of BirminghamBirmingham B152TTWest MidlandsUnited Kingdom liver Unit Queen Elizabeth HospitalUniversity Hospitals BirminghamBirmingham B152TTWest MidlandsUnited Kingdom

BACKGROUND Non-alcoholic fatty liver disease(NAFlD)is associated with obesity,insulin resistance and dyslipidaemia and currently is estimated to affect up to a third of all individuals in developed *** standard of care for patients varies according to disease stage,but includes lifestyle interventions common insulin sensitizers,antioxidants and lipid ***,to date specific therapies have shown little histological or fibrosis stage improvement in large clinical trials,and there is still no licensed therapy for *** the high prevalence,limited treatment options and significant screening costs for the general population,new treatments are urgently *** To assess the potential for inhibition of the amine oxidase enzyme vascular adhesion protein-1(VAP-1)to modify hepatic lipid accumulation in *** We have used immunochemical and qPCR analysis to document expression of VAP-1 and key functional proteins and transporters across the NAFlD *** then utilised hepatocytes in culture and human precision cut liver slices in concert with selective enzyme activity inhibitors to test the effects of activating the semicarbazide-sensitive amine oxidase activity of VAP-1 on hepatic lipid uptake and triglyceride export.A murine model of NAFlD was also used to determine the consequences of VAP-1 knockout and gene expression arrays were used to quantify the effects of VAP-1 activity on key lipid modifying and proinflammatory gene *** We confirmed that increasing severity of NAFlD and progression to cirrhosis was associated with a significant increase in hepatocellular VAP-1 *** in vitro exposed to recombinant VAP-1 and its substrate methylamine showed increased lipid accumulation as determined by quantification of Oil Red O *** was recapitulated using hydrogen peroxide,and lipid accumulation was accompanied by changes in expression of the lipid transporter molecules FABP3,FATP6,insulin recep

关键词： Non-alcoholic fatty liver disease Hepatocyte lipid Cell biology Vascular adhesion protein-1 Steatosis

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Distribution of Fucosylated Xyloglucans among the Walls of Different Cell Types in Monocotyledons Determined by Immunofluorescence Microscopy

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Molecular Plant 2011年第1期4卷 144-156页

作者： Maree Brennan philip J. Harris School of Biological Sciences The University of Auckland Private Bag 92019 Auckland New Zealand

Xyloglucans in the non-lignified primary cell walls of different species of monocotyledons have diverse struc- tures, with widely varying proportions of oligosaccharide units that contain fucosylated side chains （F side chains）. To determine whether fucosylated xyloglucans occur in all non-lignified walls in a range of monocotyledon species, we used immunofluorescence microscopy with the monoclonal antibody CCRC-M1. The epitope of this antibody, α-l-FUCp-（1 →2）- β-D-Galp, occurs in F side chains. In most non-commelinid monocotyledons, the epitope was found in all non-lignified walls. A similar distribution was found in the palm Phoenix canariensis, which is a member of the basal commelinid order Arecales. However, in the other commelinid orders Zingiberales, Commelinales, and Poales, the occurrence of the epitope was restricted, sometimes occurring in only the phloem walls, but often also in walls of other cell types including stomatal guard and subsidiary cells and raphide idioblasts. No epitope was found in the walls of the commelinids Tradescantia virginiana （Commelinaceae, Commelinales） and Zea mays （Poaceae, Poales）, but it occurred in the phloem walls of two other Poaceae species, lolium multiflorum and l. perenne. The distribution of the epitope is discussed in relation to xyloglucan structures in the different taxa. However, the functional significance of the restricted distributions is unknown.

关键词： Commelinid monocotyledons fucosylated xyloglucans immunofluorescence microscopy monoclona antibody CCRC-M1 non-commelinid monocotyledons plant cell wall.

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