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Experimental demonstration of a silicon nanophotonic antenna for far-field broadened optical phased arrays

Photonics Research 2024年第9期12卷 1954-1961页

作者： SHAHRZAD KHAJAVI JIANHAO ZHANG PAVEL CHEBEN DANIELE MELATI JENS H.SCHMID ross cheriton MARTIN VACHON SHURUI WANG AHMAD ATIEH CARLOS ALONSO RAMOS WINNIE N.YE Department of Electronics Carleton UniversityOttawaOntario K1S 5B6Canada National Research Council Canada OttawaOntario K1A 0R6Canada Centre for Nanoscience and Nanotechnologies CNRSUniversitéParis-Saclay91120 PalaiseauFrance Optiwave Systems Inc. NepeanOntario K2E 8A7Canada

Optical antennas play a pivotal role in interfacing integrated photonic circuits with free-space *** antennas for optical phased arrays ideally requires achieving compact antenna apertures,wide radiation angles,and high radiation efficiency all at once,which presents a significant ***,we experimentally demonstrate a novel ultra-compact silicon grating antenna,utilizing subwavelength grating nanostructures arranged in a transversally interleaved topology to control the antenna radiation *** near-field phase engineering,we increase the antenna’s far-field beam width beyond the Fraunhofer limit for a given aperture *** antenna incorporates a single-etch grating and a Bragg reflector implemented on a 300-nm-thick silicon-oninsulator(SOI)*** characterizations demonstrate a beam width of 44°×52°with−3.22 dB diffraction efficiency,for an aperture size of 3.4μm×1.78μ***,to the best of our knowledge,a novel topology of a 2D antenna array is demonstrated for the first time,leveraging evanescently coupled architecture to yield a very compact antenna *** validated the functionality of our antenna design through its integration into this new 2D array ***,we demonstrate a small proof-of-concept two-dimensional optical phased array with 2×4 elements and a wide beam steering range of 19.3º×39.7º.A path towards scalability and larger-scale integration is also demonstrated on the antenna array of 8×20 elements with a transverse beam steering of 31.4º.

关键词： antenna optical arrays

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The Moon

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Acta Geochimica 2016年第1期35卷 1-13页

作者： ross taylor australian national university CanberraAustralia

Recent geochemical and geophysical data from the Moon enable a revision of earlier interpretations regarding lunar origin, structure and bulk composition. Earth and Moon show many similarities among their isotopic compositions, but they have evolved in totally dissimilar ways, probably related to the deficiency of water and volatile elements in the Moon as well as the vast differences in size and internal pressure. Some global geochemical differences from the Earth such as volatile depletion based on K/U ratios have been established. However, all current lunar samples come from differentiated regions, making the establishment of a bulk composition more reliant on bulk geophysical properties or isotopic similarities; it remains unclear how the latter arose or relate to whole Moon composition. The lack of fractionation effects among the refractory and super-refractory elements indicates that the proto-lunar material seems unlikely to have been vaporized while the presence of volatile elements may place lower limits on proto-lunar temperatures. The apparent lack of geochemical evidence of an impacting body enables other possible impactors, such as comets, to be considered. Although the origin of the Moon remains currently unknown, it is generally believed that the Moon originated as the result of a giant impact on the Earth.

关键词： Lunar origin Grand tack model Apollo Volatite elements

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The future of retinal gene therapy: evolving from subretinal to intravitreal vector delivery

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Neural Regeneration Research 2021年第9期16卷 1751-1759页

作者： Maya ross Ron Ofri Koret School of Veterinary Medicine The Hebrew University of JerusalemRehovotIsrael

Inherited retinal degenerations are a leading and untreatbale cause of blindness, and as such they are targets for gene therapy. Numerous gene therapy treatments have progressed from laboratory research to clinical trails, and a pioneering gene therapy received the first ever FDA approval for treating patients. However, currently retinal gene therapy mostly involves subretinal injection of the therapeutic agent, which treats a limited area, entails retinal detachment and other potential complications, and requires general anesthesia with consequent risks, costs and prolonged recovery. Therefore there is great impetus to develop safer, less invasive and cheapter methods of gene delivery. A promising method is intravitreal injection, that does not cause retinal detachment, can lead to pan-retinal transduction and can be performed under local anesthesia in outpatient clinics. Intravitreally-injected vectors face several obstacles. First, the vector is diluted by the vitreous and has to overcome a long diffusion distance to the target cells. Second, the vector is exposed to the host's immune response, risking neutralization by pre-existing antibodies and triggering a stronger immune response to the injection. Third, the vector has to cross the inner limiting membrane which is both a physical and a biological barrier as it contains binding sites that could cause the vector's sequestration. Finally, in the target cell the vector is prone to proteasome degradation before delivering the transgene to the nucleus. Strategies to overcome these obstacles include modifications of the viral capsid, through rational design or directed evolution, which allow resistance to the immune system, enhancement of penetration through the inner limiting membrane or reduced degradation by intracellular proteasomes. Furthermore, physical and chemical manipulations of the inner limiting membrane and vitreous aim to improve vector penetration. Finally, compact non-viral vectors that can overcome

关键词： adeno-associated virus animal model blindness gene therapy inner limiting membrane photoreceptors retina retinitis pigmentosa vitreous

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Endarterectomy versus stenting for stroke prevention

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Stroke & Vascular Neurology 2018年第2期3卷 101-106页

作者： A ross Naylor The Leicester Vascular Institute Glenfield HospitalLeicesterUK

The European Society for Vascular Surgery(ESVS)has recently prepared updated guidelines for the management of patients with symptomatic and asymptomatic atherosclerotic carotid artery disease,with specific reference to the roles of best medical therapy,carotid endarterectomy(CEA)and carotid artery stenting(CAS).In symptomatic patients,there is a drive towards performing carotid interventions as soon as possible after onset of *** is because it is now recognised that the highest risk period for recurrent stroke is the first 7-14 days after onset of *** guidelines advise that there is a role for both CEA and CAS,but the levels of evidence are slightly lower for CAS than for *** is because 30-day risks of death/stroke in the randomised controlled trials(RCTs)were significantly higher than after CEA(especially in the first 7-14 days after onset of symptoms)and there are concerns that the results obtained in the RCTs may not be generalisable into routine clinical *** asymptomatic patients,the 2018 ESVS guidelines were the first to recommend that CEA/CAS should be targeted into a smaller cohort of patients who may be‘higher risk for stroke’on medical *** with symptomatic patients,the ESVS guidelines advise that there is a potential role for both CEA and CAS,but the levels of evidence are again slightly lower for CAS than for *** is because 30-day risks of death/stroke in the two largest RCTs,which used credentialed(experienced CAS practitioners),were only just within the accepted 3%risk threshold and there remain concerns that the results obtained in RCTs may not be generalisable into routine clinical practice.

关键词： routine prevention Surgery

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Enhanced Flexible Ramping Product Formulation for Alleviating Capacity Shortage in Look-ahead Commitment

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Journal of Modern Power Systems and Clean Energy 2022年第4期10卷 850-860页

作者： Hyeongon Park Bing Huang ross Baldick Department of Safety Engineering Pukyong National UniversityBusan 48513South Korea Midcontinent Independent System Operator CarmelIN 46032USA Department of Electrical&Computer Engineering at The University of Texas at Austin AustinUSA

The roll-out of a flexible ramping product provides independent system operators(ISOs)with the ability to address the issues of ramping capacity *** procure flexible ramping capability by committing more generating units or reserving a certain amount of headrooms of committed *** this paper,we raise the concern of the possibility that the procured flexible ramping capability cannot be deployed in realtime operations due to the unit shut-down in a look-ahead commitment(LAC)*** a solution to the issues of ramping capacity shortage,we provide a modified ramping product formulation designed to improve the reliability and reduce the expected operating *** trajectories of start-up and shutdown processes are also considered in determining the ramping capability.A new optimization problem is formulated using mixed integer linear programming(MILP)to be readily applied to the practical power system *** performance of this proposed method is verified through simulations using a small-scale system and IEEE 118-bus *** simulation results demonstrate that the proposed method can improve the generation scheduling by alleviating the ramping capacity shortages.

关键词： Flexible ramping product look-ahead commitment(LAC) mixed integer linear programming(MILP) reliability

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True polar wander in the Earth system

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Science China Earth Sciences 2023年第6期66卷 1165-1184页

作者： Chong WANG ross N.MITCHELL State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

True polar wander(TPW),or planetary reorientation,is the rotation of solid Earth(crust and mantle)about the liquid outer core in order to stabilize Earth’s rotation due to mass *** TPW is well-documented on Earth presently with satellites and for multiple planets and moons in the Solar System,the prevalence of TPW in Earth history remains *** a history of controversy,both the physical plausibility of TPW on Earth and an empirical basis for it are now *** resistance to the old idea likely stems from the fact that,like plate tectonics,TPW may influence much of the Earth system,thus acknowledging its existence requires rethinking how many different datasets are *** review summarizes the development of TPW as a concept and provides a framework for future research that no longer regards TPW like a ghost process that may or may not exist,but as an integral part of the Earth system that can relate shallow and deep processes that are otherwise only mysteriously ***,we focus on the temporal regularity of large TPW,and discuss its relationship with the supercontinent-megacontinent cycle based on previous *** suggest the assembly of megacontinents has a close linkage to large ***,supercontinent tenure and breakup have a close linkage to fast *** effects of TPW on sea level changes,paleoclimate,biological diversity,and other facets of the Earth system are presented and require interdisciplinary tests in the future.

关键词： True polar wander(TPW) Planetary reorientation Apparent polar wander(APW) Mantle convection Supercontinent cycle Megacontinent

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Hydrologic Modeling Impacts of Post-mining Land Use Changes on Streamflow of Peace River, Florida

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Chinese Geographical Science 2015年第6期25卷 728-738页

作者： ZHANG Jing Mark ross Key Laboratory of Resource Environment and GIS in Beijing Capital Normal University Department of Civil and Environmental Engineering University of South Florida

Whether mining activity results in reduced flow of surface water in the Peace River Watershed of Florida has been the subject of much debate. With increased dependence of downstream users on surface water flow of the Peace River as a source of drinking water for four coastal counties in Southwest Florida and problems of water security, the debate has been intensified. It is possible to assess relationships of mining with streamflow in the upper reaches of the Peace River Basin using hydrologic modeling and identify mined sub-basins. In this work, land-use change impacts were simulated by the Hydrological Simulation Program--Fortran （HSPF） model based on geographical information system （GIS） tools, to compare pre- and post-mining streamflows at a study site of the Peace River in west-central Florida. The purpose of this study was to determine if land-use changes caused by mining have negatively impacted streamflow in the Peace River. Changes of land use were identified before and after mining activities. A coupled volume-water depth-discharge （V-h-Q） model based on stage/storage and stage/discharge was applied using HSPF for the pre-mining and post-mining models, respectively. Daily simulated post-mining hydrographs from HSPF were plotted with the calibrated pre-mining results and streamflow hydrographs from the 18 gauging stations, to compare timing of peaks, low fows and flow trends. Analyses of percent ex- ceedances of flow frequency curves of the streams indicated that most streams had similar distributions for mined （reclaimed） and pre- mining periods. In the streamflow change analysis, streamflows actually increased in mining-affected basins at nearly half the stations. Streamflows at other stations diminished. Overall from this comprehensive study, there were declines in streamflow at most gauging stations on the mainstem of the Peace River and its tributaries. The results of this study suggest that regional planning is urgently needed to propose reclamation s

关键词： post-mining land-use changes streamflow hydrologic model Hydrological Simulation Program--Fortran (HSPF) model

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Testing decreasing variabililty of cockroach forewings through time using four Recent species： Blattella germanica, Polyphaga aegyptiaca, Shelfordella lateralis and Blaberus craniifer, with implications for the study of fossil cockroach forewings

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Insect Science 2012年第2期19卷 129-142页

作者： Andrew J. ross Department of Natural Sciences National Museums Scotland Edinburgh UK

Vrsansky, （2000） considered there is decreasing variability in the forewings of cockroaches through time, based on a study of fossil and Recent species. This study tests his theory, based on a study of four Recent species of cockroaches： Blattella germanica （Blattellidae）, Polyphaga aegyptiaca （Polyphagidae）, Shelfordella lateralis （Blattidae） and Blaberus craniifer （Blaberidae）. The new results, based on the coefficient of variation （CV） of the number of veins, indicate that Recent species can be more variable than fossil species and therefore do not support the theory. The results also show that at least 30 complete wings of the same species are required for a reliable CV value that is compa- rable between species.

关键词： Blaberidae Blattellidae Blattidae cockroach Polyphagidae variation

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Microstructure and Mechanical Properties of Cold Metal Transfer Welding Similar and Dissimilar Aluminum Alloys

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Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 715-724页

作者： Ahmed Elrefaey Nigel G.ross LKR Leichtmetallkompetenzzentrum Ranshofen GmbH Austrian Institute of Technology

Integrating structures made from aluminum alloys in automotive industry requires a large amount of joining. As a consequence, the properties of the joints have a significant influence on the overall performance of the whole structure. Robot cold metal transfer welding is a relatively new joining technique and has been used in this work to join 6082-T4 and 5182-O aluminum alloy sheets by using ER5356 and ER4043 filler metals. Microstructure characterization was performed by optical microscopy and energy dispersive X-ray spectroscopy, and the mechanical properties were measured by tensile and hardness tests. A correlation is made between welding variables, mechanical properties and the microstructure of welded joints. Results indicate that robot cold metal transfer welding provides good joint efficiency with high welding speed, good tensile strength, and ductility. Owing to the low heat input of robot cold metal transfer welding process, the heat affected zone microstructure was quite similar to base metals, and weld metal microstructure was the controlling factor of joint efficiency. The best performing were the 5182/5182 joints welded with ER5356 and these had mechanical property coefficients of 100%, 98%, and 85% for yield strength, ultimate tensile strength, and elongation, respectively.

关键词： Aluminum CMT Welding Microstructure Tensile property

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Anthropogenic Sulfate and Nitrate Signals in Snow from Bogda Glacier, Eastern Tianshan

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Journal of Earth Science 2011年第4期22卷 490-502页

作者：张晓宇 ross Edwards State Key Laboratory of Cryospheric Sciences/Tianshan Glaciological Station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences Desert Research Institute Reno NV 89512-1095 USA Curtin University of Technology Bentley WA6102 Australia

A 1.2 m snow pit was recovered on July 29th, 2009 from the Bogda Glacier, eastern Tianshan （天山）. The sample site temperature of -9.6 12 indicates that the unique glaciochemical re- cord was well preserved and suitable for the reconstruction of air pollution levels in this previously un- explored region. Samples were analyzed for major ions （Na＋, K＋, Ca2＋, Mg2＋, NH4＋, Cl-, SO42-, NO3-, HCOO＇, and CHaCOO）. NO3 and SO42were characterized by significant high levels of pollution con- centration. Most air masses backward trajectories ending in December 2008 have passed the Urumqi City center, while some even traveled across the primary nuclear weapons testing venue of the former Soviet Union （STS）. The mean pH value of snow samples is coincident with the average value of Urumqi＇s aerosol, and the ratio of [NO3-]/[SO42-] in the snow pit generally agrees with the value of the Urumqi winter aerosols. In addition, the [HCOO]/[CH3COO] ratio of snow samples is only 0.7, lower than unity. These analyses indicate that SO42 and NO3in the Bogda Glacier are the result of anthropo- genic pollutions.

关键词： anthropogenic pollutions SO42- NO3.

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