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Ultra-high suppression microwave photonic bandstop filters

Chinese Science Bulletin 2014年第22期59卷 2684-2692页

作者： David Marpaung Blair Morrison Mattia Pagani Ravi Pant benjamin j.eggleton Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS) the Institute of Photonics and Optical Sciences (IPOS) School of Physics University of Sydney Sydney NSW 2006 Australia

A bandstop radio frequency(RF)filter can enhance the capabilities of RF communication systems by removing unwanted signal components such as distortion,or *** modern cognitive radio systems,frequency agile filters are desired to block interferers with dynamically changing frequencies and *** filters should be tunable over a broad frequency range,and they should be capable of suppressing very strong signals with a high *** simultaneously meet these requirements with traditional RF filters are highly *** photonic(MWP),a technology that primary deals with the generation,distribution,and processing of high speed RF signals using photonic techniques and components,is promising for creating frequency agile RF ***,traditional MWP filters are lacking the high resolution and peak suppression exhibited by state-ofthe-art RF electrical *** recently introduced a new class of MWP notch filter which is free from this *** scheme allowed the creation of anomalously high suppression MWP notch filter from virtually any kind of optical resonance,irrespective of its type(gain or absorption),or its *** enabled,for the first time,simultaneous optimization of the MWP filter resolution,peak attenuation,and frequency tuning *** this paper,we present the analysis of notch filter response creation using the novel sideband processing *** thenshow the applicability of this technique to a wide range of optical *** compare simulated and experimental results of the notch filter response created using three types of optical filter commonly used in MWP signal processing,namely stimulated Brillouin scattering(SBS),an integrated optical ring resonator(ORR),and a phase-shifted fiber Bragg-grating(FBG).

关键词： RF滤波器微波光子陷波滤波器光学滤波器受激布里渊散射 RF信号光子技术频率捷变

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Multidimensional synthetic chiral-tube lattices via nonlinear frequency conversion

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Light(Science & Applications) 2020年第1期9卷 803-812页

作者： Kai Wang Bryn A.Bell Alexander S.Solntsev Dragomir N.Neshev benjamin j.eggleton Andrey A.Sukhorukov Nonlinear Physics Centre Research School of PhysicsThe Australian National UniversityCanberraACT 2601Australia Institute of Photonics and Optical Science(IPOS) School of PhysicsUniversity of SydneySydneyNSW 2006Australia Department of Physics QOLSImperial College LondonLondon SW72AZUK School of Mathematical and Physical Sciences University of Technology SydneyUltimoNSW 2007Australia Ginzton Laboratory Stanford UniversityStanfordCA 94305USA

Geometrical dimensionality plays a fundamentally important role in the topological effects arising in discrete *** direct experiments are limited by three spatial dimensions,the research topic of synthetic dimensions implemented by the frequency degree of freedom in photonics is rapidly *** manipulation of light in these artificial lattices is typically realized through electro-optic modulation;yet,their operating bandwidth imposes practical constraints on the range of interactions between different frequency *** we propose and experimentally realize all-optical synthetic dimensions involving specially tailored simultaneous short-and long-range interactions between discrete spectral lines mediated by frequency conversion in a nonlinear *** realize triangular chiral-tube lattices in three-dimensional space and explore their four-dimensional *** implement a synthetic gauge field with nonzero magnetic flux and observe the associated multidimensional dynamics of frequency combs,all within one physical spatial *** anticipate that our method will provide a new means for the fundamental study of high-dimensional physics and act as an important step towards using topological effects in optical devices operating in the time and frequency domains.

关键词： dimensions chiral nonlinear

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Thermo-optically tunable spectral broadening in a nonlinear ultra-silicon-rich nitride Bragg grating

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Photonics Research 2021年第4期9卷 596-604页

作者： Yanmei Cao Ezgi Sahin ju Won Choi Peng Xing George F.R.Chen D.K.T.Ng benjamin j.eggleton Dawn T.H.Tan Photonics Devices and Systems Group Singapore University of Technology and Design8 Somapah RoadSingapore 487372Singapore Current address:Photonic Systems Laboratory(PHOSL) Ecole Polytechnique Fédérale de LausanneSTI-IELStation 11CH-1015 LausanneSwitzerland Institute of Microelectronics A*STAR2 Fusionopolis Way#08-02Innovis TowerSingapore 138634Singapore Institute of Photonics and Optical Science School of PhysicsThe University of SydneySydneyNew South Wales 2006Australia The University of Sydney Nano Institute(Sydney Nano) The University of SydneySydneyNew South Wales 2006Australia

Spectral tunability methods used in optical communications and signal processing leveraging optical,electrical,and acousto-optic effects typically involve spectral truncation that results in energy *** we demonstrate temperature tunable spectral broadening using a nonlinear ultra-silicon-rich nitride device consisting of a 3-mm-long cladding-modulated Bragg grating and a 7-mm-long nonlinear channel *** operating at frequencies close to the grating band edge,in an apodized Bragg grating,we access strong grating-induced dispersion while maintaining low losses and high *** further exploit the redshift in the Bragg grating stopband due to the thermo-optic effect to achieve tunable dispersion,leading to varying degrees of soliton-effect compression and self-phase-modulation-induced spectral *** observe an increase in the bandwidth of the output pulse spectrum from 69 to 106 nm as temperature decreases from 70℃ to 25℃,in good agreement with simulated results using the generalized nonlinear Schrödinger *** demonstrated approach provides a new avenue to achieve on-chip laser spectral tuning without loss in pulse energy.

关键词： tunable tuning nonlinear

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混动发动机三火花塞点火系统及高热效率研究

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内燃机学报 2025年第1期43卷 20-28页

作者：闫博文 benjamin Waters 胡铁刚邓伟重庆长安汽车股份有限公司重庆400000 长安英国研究中心伯明翰B377YG英国

基于一台3缸1.5 L混动发动机,研究了单火花塞、被动预燃室及三火花塞3种不同点火方式对发动机稀燃工况下燃烧和排放特性的影响.通过2000 r/min转速、0.8 MPa平均有效压力下的测试表明:在高滚流下,采用被动预燃室点火能实现的稀燃极限对... 详细信息

基于一台3缸1.5 L混动发动机,研究了单火花塞、被动预燃室及三火花塞3种不同点火方式对发动机稀燃工况下燃烧和排放特性的影响.通过2000 r/min转速、0.8 MPa平均有效压力下的测试表明:在高滚流下,采用被动预燃室点火能实现的稀燃极限对应过量空气系数φ_(a)约为1.70,相比单火花塞略低,采用三火花塞点火则可在φ_(a)>1.95的条件下稳定燃烧,进而改善燃油消耗率和NO_(x)原始排放.随着空气稀释增加,采用被动预燃室点火对燃烧相位的改善效果逐渐减弱,且使得滞燃期和燃烧持续期增加明显.相比之下,三火花塞点火可有效加快燃烧速率,尤其在φ_(a)>1.70时优势显著,其燃烧持续期相比单火花塞和被动预燃室可缩短近4℃A.通过采用φ_(a)为1.80的稀混合气配合三火花塞点火,发动机在选用研究法辛烷值(RON)为92的燃油时可实现45.06%的最高有效热效率(BTE),选用RON100燃油及进一步采用电子增压器时,最高BTE可分别提升至45.63%和47.04%.

关键词：混动发动机三火花塞点火燃烧特性热效率

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Integrated sources of photon quantum states based on nonlinear optics

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Light(Science & Applications) 2017年第1期6卷 370-381页

作者： Lucia Caspani Chunle Xiong benjamin j.eggleton Daniele Bajoni Marco Liscidini Matteo Galli Roberto Morandotti David j Moss Institute of Photonics Department of PhysicsUniversity of StrathclydeGlasgow G11RDUK Institute of Photonics and Quantum Sciences Heriot-Watt UniversityEdinburgh EH144ASUK Centre for Ultrahigh bandwidth Devices for Optical Systems(CUDOS) Institute of Photonics and Optical Science(IPOS)School of PhysicsUniversity of SydneySydneyNSW 2006Australia Dipartimento di Ingegneria Industriale e dell’Informazione Universitàdi Paviavia Ferrata 127100PaviaItaly Dipartimento di Fisica Universitàdi Paviavia Bassi 627100 PaviaItaly INRS-EMT 1650 Boulevard Lionel-BouletVarennesQuébec J3X 1S2Canada Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China National Research University of Information Technologies Mechanics and OpticsSt.PetersburgRussia Center for Microphotonics Swinburne University of TechnologyHawthornVictoria3122 Australia

The ability to generate complex optical photon states involving entanglement between multiple optical modes is not only critical to advancing our understanding of quantum mechanics but will play a key role in generating many applications in quantum *** include quantum communications,computation,imaging,microscopy and many other novel technologies that are constantly being ***,approaches to generating parallel multiple,customisable bi-and multi-entangled quantum bits(qubits)on a chip are still in the early stages of ***,we review recent advances in the realisation of integrated sources of photonic quantum states,focusing on approaches based on nonlinear optics that are compatible with contemporary optical fibre telecommunications and quantum memory platforms as well as with chip-scale semiconductor *** new and exciting platforms hold the promise of compact,low-cost,scalable and practical implementations of sources for the generation and manipulation of complex quantum optical states on a chip,which will play a major role in bringing quantum technologies out of the laboratory and into the real world.

关键词： entanglement integrated optics nonlinear optics photon pairs quantum optics quantum states

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Origin of high particle number concentrations reaching the St. Louis, Midwest Supersite

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journal of Environmental Sciences 2015年第8期27卷 219-231页

作者： benjamin de Foy james j.Schauer Department of Earth and Atmospheric Sciences Saint Louis University Civil and Environmental Engineering University of Wisconsin

Ultrafine particles are associated with adverse health effects. Total Particle Number Concentration（TNC） of fine particles were measured during 2002 at the St. Louis — Midwest supersite. The time series showed overall low level with frequent large peaks. The time series was analyzed alongside criteria pollutant measurements and meteorological observations. Multiple regression analysis was used to identify further contributing factors and to determine the association of different pollutants with TNC levels. This showed the strong contribution of sulfur dioxide（SO2） and nitrogen oxides（NO x） to high TNC levels. The analysis also suggested that increased dispersion resulting from faster winds and higher mixing heights led to higher TNC levels. Overall, the results show that there were intense particle nucleation events in a SO2 rich plume reaching the site which contributed around 29% of TNC. A further 40% was associated with primary emissions from mobile sources. By separating the remaining TNC by time of day and clear sky conditions,we suggest that most likely 8% of TNC are due to regional nucleation events and 23% are associated with the general urban background.

关键词： Atmospheric aerosols Particle number concentrations Fine particles Sulfur dioxide plumes Mobile source emissions

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Analysis of synthetic parameters for coating aluminum powders with phenyltriethoxysilane coupling agent and their effects on powder flow behavior

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Particuology 2024年第7期90卷 412-417页

作者： Lillian M.Mawby Bellamarie Ludwig benjamin j.Lear Department of Chemistry The Pennsylvania State UniversityUniversity ParkPA16802USA Applied Research Laboratory The Pennsylvania State UniversityUniversity ParkPA16802USA

Though silanization of aluminum powder is currently used to improve its flow properties,for use as an alternative fuel source,there are a wide range of experimental parameters for the process and not all of them have been thoroughly *** this is complete,it is unknown if the process is optimized in terms of time,efficiency,and ***,we report on a study into the effects of changes in humidity,degree of agitation,reaction temperature,and curing time upon the deposition of phenyl triethoxysilane into 20μm(d50)aluminum *** confirm the deposition of the coating via diffuse reflectance infrared spectroscopy and x-ray photoelectron *** then characterize the coated particles using apparent density measurements and Carney flow *** analysis of variance,we find that,of the parameters explored,only changes in cure time and reaction temperature provide meaningful changes to the apparent density,while none of our parameters produced statistically significant changes in Carney flow ***,we conclude that,when optimizing silanization of aluminum particles,environmental control of humidity is unneeded and that the reaction can be run with minimal *** ability to largely ignore these parameters is a benefit to large-scale processing.

关键词： Aluminum powder Silane Fluidization Apparent density Carney flow

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Conspecific negative density dependence in American beech

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Forest Ecosystems 2017年第3期4卷 174-181页

作者： benjamin S.Ramage Isabel j.Mangana Biology Department Randolph-Macon College

Background： One of the most important drivers of forest biodiversity is conspecific negative density dependence（CNDD）, a reduction in performance when conspecific densities are high. While the majority of CNDD research has focused on tropical forests, evidence is mounting that CNDD may also play an important role in temperate *** further explore the potential reach of this phenomenon, we investigated CNDD in American beech（Fagus grandifolia）in a mature mid-Atlantic ***： We used bivariate point pattern analyses to examine spatial relationships between large beech trees and conspecific saplings, and we also contrasted these patterns with comparable patterns for heterospecifics. In addition, to address the possibility of dispersal limitation and the associated effects on spatial patterns, we analyzed seedling density as a function of adult conspecific ***： We found that beech saplings were more repel ed from large conspecifics than large heterospecifics, despite the fact that beech seedling density was positively correlated with beech basal area. However, saplings of other canopy tree species were also repel ed from adult beech trees, suggesting a general suppressive effect. Nonetheless, the discrepancy between beech seedling and sapling densities beneath adult conspecifics suggests that beech seedling survival rates were reduced in vicinity of conspecific ***： Regardless of the extent to which beech inhibits heterospecific trees, a negative effect on conspecific recruits may be critical for biodiversity maintenance. Without this conspecific suppression, a dense layer of shade-tolerant beech saplings could form beneath adult beech trees. If this were to occur, beech would have a substantial head-start fol owing canopy disturbance, and this late-successional species could potential y dominate a stand in perpetuity,through repeated disturbance cycles.

关键词： Biodiversity Disturbance Dispersal limitation Diversity Fagus grondifolia janzen-Connell effects Mid-Atlantic Point pattern analysis Regeneration Temperate forest

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Identification of stable adsorption sites and diffusion paths on nanocluster surfaces:an automated scanning algorithm

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npj Computational Materials 2019年第1期5卷 246-253页

作者： Tibor Szilvási benjamin W.j.Chen Manos Mavrikakis Department of Chemical&Biological Engineering University of Wisconsin-Madison1415 Engineering DriveMadisonWI 53706USA

The diverse coordination environments on the surfaces of discrete,three-dimensional(3D)nanoclusters contribute significantly to their unique catalytic *** the numerous adsorption sites and diffusion paths on these clusters is however tedious and time-consuming,especially for large,asymmetric ***,we present a simple,automated method for constructing approximate 2D potential energy surfaces for the adsorption of atomic species on the surfaces of 3D nanoclusters with minimal human *** potential energy surfaces fully characterize the important adsorption sites and diffusion paths on the nanocluster surfaces with accuracies similar to current approaches and at comparable computational *** method can treat complex nanoclusters,such as alloy nanoclusters,and accounts for cluster relaxation and adsorbate-induced reconstruction,important for obtaining accurate ***,its highly parallelizable nature is ideal for modern supercomputer architectures.

关键词： properties adsorption cluster

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Compost Input Effect on Dryland Wheat and Forage Yields and Soil Quality

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Pedosphere 2018年第3期28卷 451-462页

作者： Francisco j. CALDERON Merle F. VIGIL joseph benjamin United States Department of Agriculture-Agricultural Research Service (USDA-ARS) Central Great Plains Research Station Akron80720 CO( USA)

Organic agricultural systems rely on organic amendments to achieve crop fertility requirements, and weed control must be achieved without synthetic herbicides. Our objective was to determine the crop yield and soil quality as affected by a transition from grass to dryland organic agriculture in the Central Great Plains of North America. This study evaluated three beef feedlot compost(BFC)treatments in 2010–2015 following biennial application rates: 0(control), 22.9, and 108.7 t ha^(-1) on two dryland organic cropping systems: a wheat(Triticum aestivum)-fallow(WF) rotation harvested for grain and a triticale(Triticosecale)/pea(Pisum sativum)-fallow(T/P-F) rotation harvested for forage. The triticale + pea biomass responded positively to the 108.7-t ha^(-1) BFC treatment,but not the 22.9-t ha^(-1) BFC treatment. The wheat biomass was not affected by BFC addition, but biomass N content *** feedlot compost input did not increase wheat grain yields, but had a positive effect on wheat grain Zn content. Soil total C and N contents increased with the rate of 108.7 t ha^(-1) BFC after three applications, but not with 22.9 t ha^(-1) BFC. Soil enzyme activities associated with N and C cycling responded positively to the 108.7-t ha^(-1) BFC treatment. Saturated salts were high in the soil receiving 108.7 t ha^(-1) of BFC, but did not affect crop yields. These results showed that BFC was effective in enhancing forage yields, wheat grain quality, and soil C and N, as well as specific microbial enzymes important for nutrient cycling. However, the large rates of BFC necessary to elicit these positive responses did not increase grain yields, and resulted in an excessive buildup of soil P.

关键词： organic agriculture soil C soil enzyme activity soil N pea triticale

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