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Lithography-Free Fabrication of High Quality Substrate- Supported and Freestanding Graphene Devices

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Nano Research 2010年第2期3卷 98-102页

作者： Wenzhong Bao Gang Liu Zeng Zhao Hang Zhang Dong Yan Aparna Deshpande Brian LeRoy Chun Ning Lau Department of Physics and Astronomy University of CaliforniaRiversideCA 92521USA Center for Nanoscale Science and Engineering University of CaliforniaRiversideCA 92521USA Department of Physics University of ArizonaTucsonAZ 85721USA

We present a lithography-free technique for fabrication of clean,high quality graphene *** technique is based on evaporation through hard Si shadow masks,and eliminates contaminants introduced by lithographical *** demonstrate that devices fabricated by this technique have significantly higher mobility values than those obtained by standard electron beam *** obtain ultra-high mobility devices,we extend this technique to fabricate suspended graphene samples with mobilities as high as 120000 cm^(2)/(V·s).

关键词： Suspended graphene shadow mask mobility lithography-free e-beam evaporation

DEVS and MBSE:A review

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International Journal of Modeling, Simulation, and Scientific Computing 2022年第2期13卷 31-46页

作者： Bernard P.Zeigler Department of Electrical&Computer Engineering College of Engineering The University of Arizona TucsonAZ 85721USA RTSync Corp. ChandlerAZ 85226USA

We review Discrete-Event system Specification(DEVS)in the context of Model-based Systems Engineering(MBSE)and discuss an application of DEVS methodology to *** outline support for an envisioned MBSE development cycle of DEVS top-to-bottom MBSE capability and offer an example of mapping UML activity diagrams into executable activity-based DEVS *** close with conclusions and future research directions.

关键词： Discrete-event system specification DEVS model-based systems engineering MBSE UML activity diagrams homomorphisms system design activity-based models

Mainchain conformation ordering self-assembly tailored room temperature phosphorescence emission

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Science China Chemistry 2025年第01期 329-336页

作者： Yuzhu Li Yumeng Gao Feng Tian Yu Wang Yuan Yao Shaoliang Lin Xiang Ma Binbin Xu Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials Science and Engineering East China University of Science and Technology Shanghai Synchrotron Radiation facility Shanghai Advanced Research Institute Chinese Academy of Sciences Key Laboratory for Advance Materials and Feringa Noble Prize Scientist Joint Research Centre Frontiers Science for Materiobiology and Dynamic Chemistry School of Chemistry and Molecular Engineering East China University of Science & Technology

Developing organic room-temperature phosphorescence （RTP） materials with a wide range of tunable-emission is significant in expanding the applications of RTP ***,we rationally designed amphiphilic alternating copolymers poly(1,2-bis（4-alkoxyphenyl）ethane-1,2-dione-alt-（ethylene glycol）x)(P（Bz-alt-EGx）) that combined the advantage of alternating benzil and EGxskeleton,and tunable mainchain *** a mainchain conformation ordering assembly （COA） process,P（Bz-alt-EGx） self-assembled into well-defined platelets,and such assemblies emitted blue RTP at ca.425 nm due to the ordered folded-chain conformation and confined *** contrast,traditional self-assembly （TA） of P（Bz-alt-EGx） obtained less ordered aggregates,such as asymmetric worms,vesicles,and rod-like *** resultant less ordered aggregates exhibited yellow-green RTP at ca.550 *** wide-tuning RTP emission in solution （between blue and yellow-green,over125 nm） is realized using the P（Bz-alt-EGx） alternating copolymers under the treatment of different self-assembly *** study uncovers a new strategy to tailor the RTP emission through different self-assembly pathways and holds great promise for the fabrication of advanced optical materials.

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Calculation of First Sound Speed in Liquid Helium

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Chinese Physics Letters 1999年第4期16卷 276-278页

作者： PAO Lu Joseph P.Foy Department of Physics and Astronomy Arizona State UniversityTempeArizona 85287USA

The speed of first sound in liquid helium II is calculated quantum *** calculation is made by using a modified version of Brueckner and Sawada’s method[***.106(1959)1128]and is based on the postulate that the hard co... 详细信息

关键词： quantum Sound sound

Ultra-high-Q free-space coupling to microtoroid resonators

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Light(Science & Applications) 2024年第4期13卷 682-695页

作者： Sartanee Suebka Euan McLeod Judith Su Wyant College of Optical Sciences University of ArizonaTucsonAZUSA Department of Biomedical Engineering University of ArizonaTucsonAZUSA

Whispering gallery mode(WGM)microtoroid resonators are one of the most sensitive biochemical sensors in existence,capable of detecting single *** main barrier for translating these devices out of the laboratory is that light is evanescently coupled into these devices though a tapered optical *** hinders translation of these devices as the taper is fragile,suffers from mechanical vibration,and requires precise ***,we eliminate the need for an optical fiber by coupling light into and out from a toroid via free-space coupling and monitoring the scattered resonant light.A single long working distance objective lens combined with a digital micromirror device(DMD)was used for light injection,scattered light collection,and *** obtain Q-factors as high as 1:6´108 with this *** induced transparency(EIT)-like and Fano resonances were observed in a single cavity due to indirect coupling in free *** enables improved sensing *** large effective coupling area(~10μm in diameter for numerical aperture=0.14)removes the need for precise *** performance was verified by combining the system with the frequency locked whispering evanescent resonator(FLOWER)approach to perform temperature sensing experiments.A thermal nonlinear optical effect was examined by tracking the resonance through FLOWER while adjusting the input *** believe that this work will be a foundation for expanding the implementation of WGM microtoroid resonators to real-world applications.

关键词： coupling scattered precise

Numerical Simulations of Backward-to-Forward Leaky-Wave Antenna with Composite Right/Left-Handed Coplanar Waveguide

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Chinese Physics Letters 2010年第3期27卷 148-151页

作者：司黎明孙厚军吕昕 Department of Electronic Engineering School of Information Science and Technology Beijing Institute of Technology Beijing 100081 Electrical and Computer Engineering Department University of Arizona Tucson AZ 85721 USA

A composite right/left-handed （CRLH） coplanar waveguide （CPW） structure and its leaky-wave antenna （LWA） with continuous backward-to-forward scanning applications are proposed. The structure of the CRLH transmission line （TL） is composed of split-ring resonators （SRRs） for left-handed （LH） series capacitance and short-circuited stubs connected between the CPW central signal line and the ground for LH shunt inductance, while the unavoidable right-handed （RH） parasitic effects series inductance and shunt capacitance are generated by wave propagation through the host transmission line. The dispersion relations are calculated and compared with the equivalent circuit model method and 3D full-wave simulations, which can be used to determine the physical dimensions of the CRLH-CPW, such as in the balanced CRLH-TL case. As a main example, a CRLH-CPW-LWA operating from 1.67 GHz to 1.80 GHz with the dispersion characteristics of the balanced CRLH-TL case shows continuous leakage frequency band （fast wave region） from LH （phase constant β 〈0, .67〈f〈1.74 GHz） to RH （β〉0, 1.74〈f〈1.80 GHz） state through the transition frequency point （β=0, f=1.74 GHz）, whereas conventional LWAs operated in RH state only provide forward scanning capabilities （β〉0）.

关键词： Condensed matter: electrical magnetic and optical Electronics and devices Optics quantum optics and lasers

Interest-suppression-based NDN live video broadcasting over wireless LAN

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Frontiers of Computer Science 2017年第4期11卷 675-687页

作者： Menghan LI Dan PEI Xiaoping ZHANG Beichuan ZHANG Ke XU Tsinghua National Laboratory for Information Science and Technology (TNList) Department of Computer Science and Technology Tsinghua University Beijing 100084 China Department of Computer Science The University of Arizona Tucson AZ 85721-0001 USA

Named data networking （NDN） is a new Internet architecture that replaces today＇s focus on where - addresses and hosts with what -- the content that users and applications care about. One of NDN＇s prominent advantages is scalable and efficient content distribution due to its native support of caching and multicast in the network. However, at the last hop to wireless users, often the WiFi link, current NDN im- plementation still treats the communication as multiple uni- cast sessions, which will cause duplicate packets and waste of bandwidth when multiple users request for the same popular content. WiFi＇s built-in broadcast mechanism can alleviate this problem, but it suffers from packet loss since there is no MAC-layer acknowledgement as in unicast. In this paper, we develop a new NDN-based cross-layer approach called NLB for efficient and scalable live video streaming over wireless LAN. The core ideas are： using WiFi＇s broadcast channel to deliver content from the access point to the users, a leader- based mechanism to suppress duplicate requests from users, and receiver-driven rate control and loss recovery. The design is implemented and evaluated in a physical testbed comprised of one software AP and 20 Raspberry Pi-based WiFi clients. While NDN with multiple unicast sessions or plain broadcast can support no more than ten concurrent viewers of a 1Mbps streaming video, NDN plus NLB supports all 20 viewers, and can likely support much more when present.

关键词： NDN video broadcast WLAN

Nesting tree characteristics of heronry birds of urban ecosystems in peninsular India： implications for habitat management

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Current Zoology 2017年第6期63卷 599-605页

作者： Ramesh ROSHNATH Palatty Allesh SINU Department of Animal Science Central University of Kerala Padannakad Kerala PO 671314 India Department of Ecology and Evolutionary Biology Bioscience West University of Arizona Tucson AZ 85721 USA

Wetland ecosystems, particularly the mangrove forest, are the primary wild habitat of heronry birds. However, urban ecosystems have become a favorite breeding habitat of these birds. To provide inputs into the habitat management for conservation of these birds, we investigated the quantitative and qualitative characteristics of nesting trees of heronry birds in the urban environment of the North Kerala region of peninsular India. Census on nesting trees was done in 3 major microhabitats of the urban ecosystem： avenues of national highways and towns, nonresidential plots, and residential areas apart from the mangrove islets in the peri-urban locality. The study found that 174 trees of 22 species hosted 1,928 heronry bird nests in the urban habitats; mangrove forests, although plentiful in the study area, hosted only about 20% of the total nests encountered in the study. Rain trees Samanea saman （43.7%） were the most available nesting tree. The greatest number of nests and nesting trees were encountered on the roads of urban areas, followed by nonresidential areas and residential areas. The differences in the observed frequencies of nesting trees in 3 microhabitats and in 3 types of roads （national highways 〉 state highways 〉 small pocket road） were significant. Canopy spread, girth size, and quality of the trees predicted the tree selection of the heronry birds in urban environments. Therefore, we recommend proper management and notification of the identified nesting trees as protected sites for the conservation of herorny birds.

关键词： avenue trees heronry management urban ecosystem.

Co-axial depth sensor with an extended depth range for AR/VR applications

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Virtual Reality & Intelligent Hardware 2020年第1期2卷 1-11页

作者： Mohan XU Hong HUA 3D Visualization and Imaging Systems Laboratory College of Optical SciencesUniversity of Arizona1630 East University BoulevardTucsonAZ 85721USA

Background Depth sensor is an essential element in virtual and augmented reality devices to digitalize users'environment in real *** current popular technologies include the stereo,structured light,and Time-of-Flight(ToF).The stereo and structured light method require a baseline separation between multiple sensors for depth sensing,and both suffer from a limited measurement *** ToF depth sensors have the largest depth range but the lowest depth map *** overcome these problems,we propose a co-axial depth map sensor which is potentially more compact and cost-effective than conventional structured light depth ***,it can extend the depth range while maintaining a high depth map ***,it provides a high-resolution 2 D image along with the 3 D depth *** This depth sensor is constructed with a projection path and an imaging *** two paths are combined by a beamsplitter for a co-axial *** the projection path,a cylindrical lens is inserted to add extra power in one direction which creates an astigmatic *** depth measurement,the astigmatic pattern is projected onto the test scene,and then the depth information can be calculated from the contrast change of the reflected pattern image in two orthogonal *** extend the depth measurement range,we use an electronically focus tunable lens at the system stop and tune the power to implement an extended depth range without compromising depth *** In the depth measurement simulation,we project a resolution target onto a white screen which is moving along the optical axis and then tune the focus tunable lens power for three depth measurement subranges,namely,near,middle and *** each sub-range,as the test screen moves away from the depth sensor,the horizontal contrast keeps increasing while the vertical contrast keeps decreasing in the reflected ***,the depth information can be obtained by computing the contrast ratio between fe

关键词： Depth map sensor 3 D camera Controlled aberration