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High pressure luminescence studies of europium doped GaN

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Journal of Rare Earths 2009年第4期27卷 667-670页

作者： K.wisniewski w.Jadwisieńczak t.thomas M.Spencer Institute of of Experimental Physics Gdańsk University ul.Wita Stwosza 57 Gdańsk 80-952 Poland School of Electrical Engineering and Computer Science Ohio-University Athens OH 45701 USA Second of Electrical and Computer Engineering Cornell University Ithaca NY 14853 USA

we reported on the high pressure luminescence spectra of polycrystalline Eu-doped GaN material synthesized in the reaction between alloys of gallium, bismuth and europium in ammonia atmosphere. the integrated luminescence intensity of the dominant Eu3＋ ion transition （5D0→^7F2） at 622 nm increased approximately one order of rnagnitude whereas its spectral position and line width did not change significantly between ambient and 6.8 GPa pressure, respectively. Moreover, material was characterized with photo- and cathodo-luminescence, and photoluminescence excitation spectra at different temperatures. It was found that the Eu3＋ ions occupying substitutional Ga site created different centers which could be effectively excited with above band gap excitation and from excitons resonantly photoexcited at the I2 bound exciton energy. Furthermore, the less efficient Eu3＋ ions excitation path existed through intrinsic impurities and defeels generating shallow energy levels in the forbidden gap. It was proposed that reduction of the thermal quenching and consequent enhancement of Eu3＋ ion emission intensity resulted from stronger localization of bound exciton on RESI trap induced by applied pressure.

关键词： GaN, Eu^3+ ion high pressure spectroscopy rate earths

Labial tip sensilla of Blissus leucopterus leucopterus （Hemiptera： Blissidae）： Ultrastructure and behavior

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Insect Science 2008年第3期15卷 271-275页

作者： Gerald t. Baker Xiong Chen Peter w.K. Ma Department of Entomology and Plant Pathology Box 9775 Mississippi State University Mississippi State MS 39762 USA

the cuticular sensory receptors that are found on the apex of the labium of hemipterans play an important role in their feeding behavior. In this study we describe the ultrastructure, number, and distribution of sensilla on the labium apex of the chinch bug, Blissus leucopterus leucopterus. Each apical field of sensilla on the labium contains 11 uniporous peg sensilla and one sensillum chaeticum. the uniporous peg sensilla are innervated by 4-5 bipolar neurons that send dendrites in the lumen of each peg. three neurons are associated with each sensillum chaeticum, two neurons have dendrites in the lumen of the sensillum, and the third dendrite ends in a tubular body at the base of the sensillum. Behavioral tests that involve chemical blockage of the sensory receptors show the importance of the labial sensilla in feeding behavior. Both morphological and behavioral evidence indicate that the labial sensilla have a chemosensitive function.

关键词： behavioral tests chinch bug electron microscopy labial sensilla Nmethylmaleimide

Integral sliding mode based optimal composite nonlinear feedback control for a class of systems

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Control theory and technology 2014年第2期12卷 139-146页

作者： Zhou ZHENG weijie SUN Hui CHEN John t. w. YEOw College of Automation Science and Engineering South China University of Technology

this paper presents an optimization method of designing the integral sliding mode （ISM） based composite nonlinear feedback （CNF） controller for a class of low order linear systems with input saturation. the optimal CNF control is first designed as a nominal control to yield high tracking speed and low overshoot. the selection of all the tuning parameters for the CNF control law is turned into a minimization problem and solved automatically by particle swarm optimization （PSO） algorithm. Subsequently, the discontinuous control law is introduced to reject matched disturbances. then, the optimal ISM-CNF control law is achieved as the sum of the optimal CNF control law and the discontinuous control law. the effectiveness of the optimal ISM-CNF controller is verified by comparing with a step by step designed one. High tracking performance is achieved by applying the optimal ISM-CNF controller to the tracking control of the micromirror.

关键词： Composite nonlinear feedback Integral sliding mode Input saturation PSO Micromirror

A ONE-StOP LOGIStIC SERVICES FRAMEwORK SUPPORtING GLOBAL SUPPLY CHAIN COLLABORAtION

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Journal of Systems Science and Systems Engineering 2016年第2期25卷 229-253页

作者： Amy J.C. trappey Charles V. trappey Sandy w.C. Chang w.t. Lee tun Nien Hsu Department of Industrial Engineering and Engineering Management National Tsing Hua University Hsinchu Taiwan China Department of Management Science National Chiao Tung University Taiwan China technology Center for Service Industries Industrial Technology Research Institute Taiwan China

A global enterprise must continuously improve the efficiency of logistic operations between supply chain collaborators. Integrating logistic services, resources, and necessary information flows in the supply chain to ensure efficiency and efficacy is critically important to these companies. Global logistic service companies face challenges from their clients to provide logistic services that are cost effective, accurate, and seamlessly integrate material, information and cash flows. In this research, an improved framework for one-stop logistic services is systematically designed, analyzed, and evaluated. the one-stop logistic service framework, defmed in four models, is developed to provide enterprises with integrated and comprehensive services within the global supply chain context. the levels of service importance are assessed using a four categories questionnaire. this research provides a case study of the implementation of one-stop logistic services in the distribution industry and demonstrates the framework operating under different demand conditions. Finally, system dynamics causal evaluation is used to evaluate the advantages of the logistic service framework.

关键词： One-stop logistic services logistic management supply chain management system dynamics modeling

Profound Carrier-Envelope-Phase-Difference Effect on Photoionization Rate： Numerical Results on a Model Hydrogen Atom

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Chinese Physics Letters 2005年第9期22卷 2230-2232页

作者：周瑜张贵忠向望华 w. t. Hill III College of Precision Instrument and Optoelectronics Engineering Tianjin University Tianjin 300072 Key Laboratory of Opto-Electronic Information technical Science (Ministry of Education) Tianjin University 300072 Institute for Physical Science and technology University of Maryland at College Park MD 20742 USA

we discuss importance of the carrier-envelope phase difference （CEPD） effect which would be encountered in real short laser pulses. By numerically simulating photoionization rate of a one-dimensional atomic hydrogen model irradiated by short light pulses, a profound CEPD effect on the photoionization rate is revealed, which might shed light on laser-atom interaction investigation. we also suggest that photoionization process might be exploited in return to measure CEPD values.

关键词： CEPD Hydrogen nodel

Buffering functions of mangroves in the 2004 tsunami

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International Journal of Digital Earth 2009年第3期2卷 257-274页

作者： t.J.Oyana w.Sun P.Sirikulchayanon Department of Geography&Environmental Resources Southern Illinois University1000 Faner DriveCarbondaleIL 62901USA Department of Geography and Planning Grand Valley State University1 Campus DriveAllendaleMI 49401USA

the complex nature of coastal ecosystems and their protection require a deeper understanding of land cover change and *** a number of ecological studies have been conducted to realise this important objective,little information is available regarding the quantification of this land cover *** role of mangroves as living barriers was under appreciated prior to the 2004 tsunami *** this paper,we investigate the buffering functions of mangroves in the 2004 tsunami by employing the methodology developed in our companion *** focus more on mangrove distribution patterns in different buffer zones before and after the 2004 *** presence of mangroves before and after the event was statistically significant for the North(χ^(2)=154.08,p50.001)and Upper South(χ^(2)=62.25,p50.001).we observed positive linear relationships suggesting a loss of mangrove resulted into a gain of barren and sand land cover as a result of a devastating impact from the 2004 tsunami *** are pockets of inland tsunami inundations and penetrations in the North and Upper-South in part owing to the river mouth profiles and dense mangrove *** the North and Upper South Regions of the study area with large mangrove forest areas suffered slight damages,these regions put up a strong buffer against the tsunami suggesting that mangrove forests play a significant role in shoreline protection.

关键词： tsunami mangrove distribution land cover change coastal ecosystem proximity analysis chi-square analysis

Enhanced Heat transfer with Full Circumferential Ribs in Helical Pipe

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Journal of thermal Science 2002年第3期11卷 241-248页

作者： S.w.Chang L.M.Su t.L.Yang Department of Marine Engineering National Kaohsiung Institute of Marine Technology Kaohsiung Taiwan China Associate Professor Department of Electrical Engineering Tong Fang College of Technology and Commerce Taiwan China Associate Professor and Head of Department Department of Electrical Engineering Fortune Institute of Technology Taiwan China

this paper describes an experimental study of heat transfers in the smooth-walled and rib-roughened helical pipes with reference to the design of enhanced cooling passages in the cylinder head and liner of a marine propulsive diesel engine. the manner in which the repeated ribs modify the forced heat convection in the helical pipe is considered for the case where the flow is turbulent upon entering the coil but laminar in further downstream. A selection of experimental results illustrates the individual and interactive effects of Dean vortices and rib-flows on heat transfer along the inner and outer helixes of coils. the experimental-based observations reveal that the centrifugal force modifies the heat transfer in a manner to generate circumferential heat transfer variation with better cooling performance on the outer edge relative to its inner counterpart even with the agitated flow field caused by the repeated ribs. Heat transfer augmentation factor in the range of 1.3 ~ 3 times of the smooth-walled

关键词： helical pipe heat transfer enhancement.

Predicting recrystallized grain size in friction stir processed 304L stainless steel

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Journal of Materials Science & technology 2019年第4期35卷 491-498页

作者： M.P.Miles t.w.Nelson C.Gunter F.C.Liu L.Fourment t.Mathis Manufacturing Engineering Department Brigham Young University Centre de Mise en Forme des Materiaux Mines ParisTech

A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. when conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone(HAZ). Friction stir processing(FSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304 L stainless steel. A numerical simulation of the FSP process in 304 L was developed to predict temperatures and recrystallized grain size in the stir zone. the model employed an Eulerian finite element approach,where flow stresses for a large range of strain rates and temperatures inherent in FSP were used as input. temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. the predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. the maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%.

关键词： Stainless steel Numerical simulation Friction stir welding Recrystallized grain size

Materials Futures—an open access journal to serve the materials science community

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Materials Futures 2022年第1期1卷 1-2页

作者： J K Zhao w H wang t Brezesinski Songshan Lake Materials Laboratory Dongguan 523808GuangdongChina Institute of Physics Chinese Academy of SciencesBeijing 100190China Institute of Nanotechnology Karlsruhe Institute of Technology(KIT)Hermann-von-Helmholtz-Platz 1Eggenstein-Leopoldshafen 76344Germany

Materials Futures is co-published by the Songshan Lake Materials Laboratory and the UK’s IOP Publishing house,with support from the Institute of Physics,Chinese Academy of *** journal is dedicated to publishing seminal works in wide-ranging areas including metals and ceramics,energy materials,nanomaterials,quantum materials and *** scope covers studies regarding novel materials,materials properties and applications,as well as materials computation,theory and design(synthesis,processing,characterization etc).It strives to serve the research community and aims to become a top-tier journal for materials science.

关键词： journal Futures ceramics