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Biomimetic flexible plate actuators are faster and more efficient with a passive attachment

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Acta Mechanica Sinica 2016年第6期32卷 1001-1011页

作者： peter D.Yeh Alexander Alexeev George W.Woodruff School of Mechanical Engineering Georgia Institute of Technology

Using three-dimensional computer simulations, we probe biomimetic free swimming of an internally actuated flexible plate in the regime near the first natural frequency. The plate is driven by an oscillating internal moment approximating the actuation mechanism of a piezoelectric macro fiber composite (MFC) bimorph. We show in our simulations that the addition of a passive attachment increases both swimming velocity and efficiency. Specifically, if the active and passive sections are of similar size, the overall performance is the best. We determine that this optimum is a result of two competing factors. If the passive section is too large, then the actuated portion is unable to generate substantial deflection to create sufficient thrust. On the other hand, a large actuated section leads to a bending pattern that is inefficient at generating thrust especially at higher frequencies.

关键词： Flexible plate Biomimetic Lattice Boltzmann Fluid-structure interaction Robotic fish Piezoelectric actuator

A multivariable output neural network approach for simulation of plug-in hybrid electric vehicle fuel consumption

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Green Energy and Intelligent Transportation 2023年第2期2卷 66-84页

作者： Bukola peter Adedeji Department of Industrial Systems Engineering University of ReginaSKS4S 0A2Canada

This study is laser focused on the simulation of fuel consumption and fuel economy label parameters of plug-in hybrid electric *** fuel economy is a key factor in the design of plug-in hybrid electric vehicles,a fuel economy label can educate customers about the economic advantage of purchasing a particular *** fuel economy label of a PHEV consists of parameters like driving range,electrical energy consumption,fuel economy for city,highway,and combined use,battery recharge time,and fuel consumption *** study used an inverse function model of an artificial neural network to simulate and calculate the parameters of the fuel economy labels of ***,the selected parameters of the fuel economy label of plug-in hybrid electric vehicles were used to develop a single output *** output variable of the single output model was then merged with dummy functions to form input variables for the inverse function *** output variables simulated were engine size in litres;estimated driving range when the battery is fully charged in km,battery recharged time in hours,city fuel consumption(L/100 km),highway fuel consumption(L/100 km),combined fuel consumption(L/100 km),estimated driving range when the tank is full,carbon dioxide(CO_(2))emission in grams/km,electric motor power in kW,number of cylinders,and electrical charges consumed in kWh/100 *** cases of input variables were considered for the inverse function *** accuracy of the model was 29.1 times greater than that of the conventional inverse artificial neural network model.

关键词： Plug-in hybrid electric vehicles Fuel economy Fuel economy label Artificial neural network Simulation

Electronic and optical properties of CdS/CdZnS nanocrystals

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Chinese Physics B 2012年第8期21卷 441-448页

作者： A.John peter Chang Woo Lee epartment of Chemical Engineering and Green Energy Center College of EngineeringKyung Hee University1 SeochunGihungYonginGyeonggi 446-701S.Korea Department of Physics Govt.Arts CollegeMelurMadurai-62510India Department of Chemical Engineering and Green Energy Center College of EngineeringKyung Hee University1 SeochunGihungYonginGyeonggi 446-701S.Korea

Cd1-xZnxS nanocrystals are prepared by a co-precipitation method with different atomic fractions of Zn. The texture, structural transformation and optical properties with increasing x value in Cd1-xZnxS are studied with scanning electron microscopy, electron diffraction patterning, and absorption spectra respectively. Quantum confinement in a strained CdS/Cd1-xZnxS related nanodot with various Zn content values is investigated theoretically. Binding energies on exciton bound CdS/CdxZn1-xS quantum dot are computed, with consideration of the internal electric field induced by the spontaneous and piezoelectric polarizations, and thereby the interband emission energy is calculated as a function of the dot radius. The optical band gap from the UV absorption spectrum is compared with the interband emission energy computed theoretically. Our results show that the average diameter of composite nanoparticles ranges from 3 nm to 6 nm. The X-ray diffraction pattern shows that all the peaks shift towards the higher diffracting angles with an increase in Zn content. The lattice constant gradually decreases as the Zn content increases. The strong absorption edge shifts towards the lower wavelength region and hence the band gap of the films increases as the Zn content increases. The values of the absorption edge are found to shift towards the shorter wave length region and hence the direct band gap energy varies from 2.5 eV for the CdS film and 3.5 eV for the ZnS film. Our numerical results are in good agreement with the experimental results.

关键词： quantum dots quasicrystals semiconductor

Radiative life time of an exciton confined in a strained GaN/Ga_(1-x)Al_xN cylindrical dot:built-in electric field effects

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Chinese Physics B 2011年第7期20卷 367-372页

作者： Chang Woo Lee A.John peter Department of Chemical Engineering and Green Energy Center College of EngineeringKyung Hee University1 SeochunGihungYonginGyeonggi 446-701Republic of Korea Department of Physics Government Arts and Science CollegeMelur-625106India

The binding energy of an exciton in a wurtzite GaN/GaAlN strained cylindrical quantum dot is investigated theoretically. The strong built-in electric field due to the spontaneous and piezoelectric polarizations of a GaN/GaAlN quantum dot is included. Numerical calculations are performed using a variational procedure within the single band effective mass approximation. Valence-band anisotropy is included in our theoretical model by using different hole masses in different spatial directions. The exciton oscillator strength and the exciton lifetime for radiative recombination each as a function of dot radius have been computed. The result elucidates that the strong built-in electric field influences the oscillator strength and the recombination life time of the exciton. It is observed that the ground state exciton binding energy and the interband emission energy increase when the cylindrical quantum dot height or radius is decreased, and that the exciton binding energy, the oscillator strength and the radiative lifetime each as a function of structural parameters （height and radius） sensitively depend on the strong built-in electric field. The obtained results are useful for the design of some opto-photoelectronic devices.

关键词： quantum dot donor bound excitons oscillator strength

Effective platform for the generation of aerosol droplets and application in evaluating the effectiveness of a MEMS-based nanoparticle trapping device

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Particuology 2009年第6期7卷 471-476页

作者： Ratna Tantra Dipak Gohil peter Cumpson National Physical Laboratory Hampton RoadTeddingtonMiddlesex TW11 0LWUnited Kingdom School of Mechanical and Systems Engineering Newcastle UniversityNewcastle-upon-Tyne NE1 7RUUnited Kingdom

The purpose of this study is two-fold： firstly, the development of a cheap, easy-to-construct and effective nanoparticle generator for testing nanoparticle sensors; secondly, the use of such a generator to test the effectiveness of a sensor device in trapping aerosolised nanoparticles. In this study, we have constructed an effective aerosol generator platform, based on aerosol-assisted chemical vapour deposition technology. Under well-controlled experimental conditions, this platform is capable of depositing aerosolised sodium chloride particles homogeneously on a substrate very effectively. Deposited aerosol droplets were subsequently dried and shown to form nanosized cubic crystals that are free from impurities. This platform was employed to test the effectiveness of a MEMS comb device in the electrostatic trapping of nanoparticles. Upon applying a DC bias （0.5 V） to the MEMS device, results showed an increase in nanoparticle deposition on the surface of the device, due to electrostatic precipitation. The presence of an electric field was shown to affect crystal formation upon drying of the aerosol droplets on the substrate; this caused a blotchy appearance on the SEM image, which was not observed in the absence of electric field.

关键词： Aerosol MEMS sensor Particle generator

Terrestrial denitrification:challenges and opportunities

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Ecological Processes 2012年第1期1卷 1-11页

作者： peter M Groffman Cary Institute of Ecosystem Studies 2801 Sharon TurnpikeMillbrookNY 12545USA

Denitrification is a process of great environmental importance but is difficult to study in terrestrial *** for quantifying the process are problematic,variability in activity is high,and temporal and spatial scaling challenges are *** methods are problematic for a variety of reasons;they change substrate concentrations,disturb the physical setting of the process,lack sensitivity or are prohibitively costly in time and *** fundamentally,it is very difficult to quantify the dominant end-product(N_(2))of denitrification given its high background concentration in the *** and temporal variation in denitrification is high due to control of the process by multiple factors(oxygen,nitrate,carbon,pH,salinity,temperature etc.)that each vary in time and space.A particular challenge is that small areas(hotspots)and brief periods(hot moments)frequently account for a high percentage of N gas flux *** phenomena are challenging to account for in measurement,modeling and scaling *** need for scaling is driven by the fact that there is a need for information on this microscale process at the ecosystem,landscape and regional scales where there are concerns about nitrogen effects on soil fertility,water quality and air *** this review,I outline the key challenges involved with denitrification and then describe specific opportunities for making progress on these challenges including advances in measurement methods,new conceptual approaches for addressing hotspot and hot moment dynamics,and new remote sensing and geographic information system–based scaling *** of these opportunities suggests that we are poised to make great improvements in our understanding of terrestrial *** improvements will increase our basic science understanding of a complex biogeochemical process and our ability to manage widespread nitrogen pollution problems.

关键词： scaling process landscape

Prediction of and for new environments: What's your model?

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Molecular Plant 2022年第4期15卷 581-582页

作者： Hans-peter Piepho University of Hohenheim Institute of Crop ScienceBiostatistics UnitFruwirthstrasse 2370599 StuttgartGermany

Genomic prediction(GP)and genome-wide association studies(GWAS)employ genetic variants(markers)to predict phenotypic performance and identify superior *** plants,due to genotype-environment interaction(GEI),performance is usually assessed across multiple environments,giving rise to phenotypic data matrices with genotypes in rows and environments in columns(Figure 1).The standard approaches to GP and GWAS employ genotype(row)means across environments as a response and analysis focuses on the *** et al.,2022 proposed to apply the same idea using environment(column)means across genotypes as the response and scanning environmental variants for their ability to predict environmental performance.

关键词： environments Figure performance

A Survey of Image Synthesis and Editing with Generative Adversarial Networks

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Tsinghua Science and Technology 2017年第6期22卷 660-674页

作者： Xian Wu Kun Xu peter Hall TNList and the Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China the Department of Computer Science University of BathBathUK

This paper presents a survey of image synthesis and editing with Generative Adversarial Networks（GANs）. GANs consist of two deep networks, a generator and a discriminator, which are trained in a competitive way. Due to the power of deep networks and the competitive training manner, GANs are capable of producing reasonable and realistic images, and have shown great capability in many image synthesis and editing *** paper surveys recent GAN papers regarding topics including, but not limited to, texture synthesis, image inpainting, image-to-image translation, and image editing.

关键词： image synthesis image editing constrained image synthesis generative adversarial networks imageto-image translation

Duality for cochain DG algebras

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Science China Mathematics 2013年第1期56卷 79-89页

作者： JφRGENSEN peter School of Mathematics and Statistics Newcastle University

This paper develops a duality theory for connected cochain DG algebras,with particular emphasis on the non-commutative *** of the main items is a dualizing DG module which induces a duality between the derived categories of DG left-modules and DG right-modules with finitely generated *** an application,it is proved that if the canonical module k=A/A≥1 has a semi-free resolution where the cohomological degree of the generators is bounded above,then the same is true for each DG module with finitely generated cohomology.

关键词： balanced dualizing complex Castelnuovo-Mumford regularity Cech DG module derived comple-tion derived torsion DG left-module DG right-module dualizing DG module endomorphism DG algebra Extregularity non-commutative DG algebra