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All-optical tuning of a diamond micro-disk resonator on silicon

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Photonics Research 2020年第3期8卷 318-324页

作者： PAUL HILL CHARALAMBOS KLITIS BENOIT GUILHABERT MARC SOREL ERdAN GU martin d.dawson MICHAEL J.STRAIN Institute of Photonics Department of PhysicsTechnology and Innovation CentreUniversity of StrathclydeGlasgow G11RDUK diamond Science and Technology Centre for Doctoral TrainingUniversity of WarwickCoventry CV47ALUK School of Engineering University of GlasgowGlasgow G128LTUK

High-quality integrated diamond photonic devices have previously been demonstrated in applications from nonlinear photonics to on-chip quantum ***,the small sample sizes of single crystal material available,and the difficulty in tuning its optical properties,are barriers to the scaling of these *** of these issues can be addressed by integrating micrometer-scale diamond devices onto host photonic integrated circuits using a highly accurate micro-assembly *** this work a diamond micro-disk resonator is integrated with a standard single-mode silicon-on-insulator waveguide,exhibiting an average loaded Q-factor of 3.1×10^4 across a range of spatial modes,with a maximum loaded Q-factor of 1.05×10^*** micrometer-scale device size and high thermal impedance of the silica interface layer allow for significant thermal loading and continuous resonant wavelength tuning across a 450 pm range using a milliwatt-level optical *** diamond-on-demand integration technique paves the way for tunable devices coupled across large-scale photonic circuits.

关键词： tuning resonator waveguide

1 Gbps free-space deep-ultraviolet communications based on Ⅲ-nitride micro-LEds emitting at 262 nm

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Photonics Research 2019年第7期7卷 19-25页

作者： Xiangyu He Enyuan Xie Mohamed Sufyan Islim Ardimas Andi Purwita Jonathan J.d.McKendry Erdan Gu Harald Haas martin d.dawson Institute of Photonics Department of PhysicsUniversity of StrathclydeGlasgow G11RDUK Li-Fi R&d Centre the University of EdinburghInstitute for Digital CommunicationsEdinburgh EH9 3JLUK

The low modulation bandwidth of deep-ultraviolet(UV) light sources is considered as the main reason limiting the data transmission rate of deep-UV communications. Here, we present high-bandwidth Ⅲ-nitride microlight-emitting diodes(μLEds) emitting in the UV-C region and their applications in deep-UV communication systems. The fabricated UV-C μLEds with 566 μm2 emission area produce an optical power of 196 μW at the 3400 A∕cm2 current density. The measured 3 dB modulation bandwidth of these μLEds initially increases linearly with the driving current density and then saturates as 438 MHz at a current density of 71 A∕cm2, which is limited by the cutoff frequency of the commercial avalanche photodiode used for the measurement. A deep-UV communication system is further demonstrated. By using the UV-C μLEd, up to 800 Mbps and 1.1 Gbps data transmission rates at bit error ratio of 3.8 × 10-3 are achieved assuming on-off keying and orthogonal frequency-division multiplexing modulation schemes, respectively.

关键词： communications Ⅲ-nitride micro-LEds

10 Gbps wavelength division multiplexing using UV-A, UV-B, and UV-C micro-LEds

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Photonics Research 2022年第2期10卷 516-523页

作者： daniel M.Maclure Jonathan J.d.McKendry Mohamed Sufyan Islim Enyuan Xie Cheng Chen Xiaobin Sun Xudong Liang Xiaohui Huang Hanaa Abumarshoud Johannes Herrnsdorf Erdan Gu Harald Haas martin d.dawson Institute of Photonics Department of PhysicsSUPAUniversity of StrathclydeGlasgow G11RDUK LiFi Research and development Centre Department of Electronic&Electrical EngineeringUniversity of StrathclydeTechnology&Innovation CentreGlasgow G11RDUK Fraunhofer Center of Applied Photonics Technology&Innovation CentreGlasgow G11RDUK Zhixin Semiconductor(Hangzhou)Co. Ltd.Hangzhou 311200China

deep ultraviolet(dUV) optical wireless communications have seen increased interest in recent years due to the unique properties of light in this spectral region. However, the reported dUV data rates remain significantly lower than comparable demonstrations at visible wavelengths due to lower modulation bandwidths and/or output power of the sources. Here, we present a wavelength division multiplexing demonstration using three UV microlight-emitting diodes emitting at nominal peak wavelengths of 285, 317, and 375 nm, respectively, each with an emitting area of approximately 1369 μm^(2)(equivalent to circular device pixels of diameter;0 μm). Using orthogonal frequency division multiplexing, data rates of 4.17, 3.02, and 3.13 Gbps were achieved from the 285, 317, and 375 nm devices, respectively, for a combined data rate of 10.32 Gbps transmitted over a distance of 0.5 m.

关键词： Gbps multiplexing diodes

Towards 10 Gb/s orthogonal frequency division multiplexing-based visible light communication using a GaN violet micro-LEd

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Photonics Research 2017年第2期5卷 35-43页

作者： MOHAMEd SUFYAN ISLIM RICARdO X.FERREIRA XIANGYU HE ENYUAN XIE STEFAN VIdEV SHAUN VIOLA SCOTT WATSON NIKOLAOS BAMIEdAKIS RICHARd V.PENTY IAN H.WHITE ANTHONY E.KELLY ERdAN GU HARALd HAAS martin d.dawson Li–Fi R&d Centre the University of Edinburgh Institute for Digital Communications Institute of Photonics Department of Physics University of Strathclyde Institute for digital Communications Li–Fi R&D Centre the University of Edinburgh School of Engineering University of Glasgow Centre for Advanced Photonics and Electronics Electrical Engineering Division Department of Engineering University of Cambridge

Visible light communication(VLC)is a promising solution to the increasing demands for wireless *** nitride micro-sized light emitting diodes(micro-LEds)are strong candidates for VLC due to their high *** violet micro-LEds are reported in this work with electrical-to-optical bandwidths up to 655 *** orthogonal frequency division multiplexing-based VLC system with adaptive bit and energy loading is demonstrated,and a data transmission rate of 11.95 Gb/s is achieved with a violet micro-LEd,when the nonlinear distortion of the micro-LEd is the dominant noise source of the VLC system.A record 7.91 Gb/s data transmission rate is reported below the forward error correction threshold using a single pixel of the segmented array when all the noise sources of the VLC system are present.

关键词： Towards 10 Gb/s orthogonal frequency division multiplexing-based visible light communication using a GaN violet micro-LEd VLC OFdM LEds

Highly Active Interfacial Sites in SFT-SnO_(2) Heterojunction Electrolyte for Enhanced Fuel Cell Performance via Engineered Energy Bands:Envisioned Theoretically and Experimentally

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Energy & Environmental Materials 2024年第3期7卷 384-397页

作者： Sajid Rauf Muhammad Bilal Hanif Faiz Wali Zuhra Tayyab Bin Zhu Naveed Mushtaq Yatao Yang Kashif Khan Peter d.Lund martin Motola Wei Xu College of Electronic and Information Engineering and State Key Laboratory of Radio frequency Heterogeneous Integration Shenzhen UniversityShenzhen 518000China department of Inorganic Chemistry Faculty of Natural SciencesComenius University in BratislavaIlkovicova 684215BratislavaSlovakia College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China School of Energy and Environment Southeast UniversityNo.2 Si Pai LouNanjing 210096China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China New Energy Technologies Group Department of Applied PhysicsAalto University School of ScienceP.O.Box 15100Fl-00076AaltoEspoo Finland

Extending the ionic conductivity is the pre-requisite of electrolytes in fuel cell technology for high-electrochemical *** this regard,the introduction of semiconductor-oxide materials and the approach of heterostructure formation by modulating energy bands to enhance ionic conduction acting as an electrolyte in fuel ***(n-type;SnO_(2))plays a key role by introducing into p-type SrFe_(0.2)Ti_(0.8)O_(3-δ)(SFT)semiconductor perovskite materials to construct p-n heterojunction for high ionic ***,two different composites of SFT and SnO_(2)are constructed by gluing p-and n-type SFT-SnO_(2),where the optimal composition of SFT-SnO_(2)(6∶4)heterostructure electrolyte-based fuel cell achieved excellent ionic conductivity 0.24 S cm^(-1)with power-output of 1004 mW cm^(-2)and high OCV 1.12 V at a low operational temperature of 500℃.The high power-output and significant ionic conductivity with durable operation of 54 h are accredited to SFT-SnO_(2)heterojunction formation including interfacial conduction assisted by a built-in electric field in fuel cell ***,the fuel conversion efficiency and considerable Faradaic efficiency reveal the compatibility of SFT-SnO_(2)heterostructure electrolyte and ruled-out short-circuiting ***,the first principle calculation provides sufficient information on structure optimization and energy-band structure modulation of SFT-SnO_(2).This strategy will provide new insight into semiconductor-based fuel cell technology to design novel electrolytes.

关键词： high ionic conductivity interfacial conduction modulated energy band structure p-n heterojunction semiconductors

Time trends and outcomes of gastrostomy placement in a Swedish national cohort over two decades

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World Journal of Gastroenterology 2024年第10期30卷 1358-1367页

作者： martin Löfling Skogar Magnus Sundbom department of Surgical Sciences Uppsala UniversityUppsala 75185Sweden

BACKGROUNd Percutaneous endoscopic gastrostomy(PEG)and laparoscopically inserted gastrostomy have become the gold standard for adult patients and children,respectively,requiring long-term enteral nutrition ***-related mortality is a rare event,often reported to be zero in smaller *** data on 30-d mortality and long-term survival rates after gastrostomy placement are scarce in the *** To study the use of gastrostomies in Sweden from 1998-2019 and to analyze procedure-related mortality and short-term(d)and long-term *** In this retrospective,population-based cohort study,individuals that had received a gastrostomy between 1998-2019 in Sweden were *** were identified in the Swedish National Patient Register,and survival analysis was possible by cross-referencing the Swedish death *** cohort was divided into three age groups:Children(0-18 years);adults(19-64 years);and elderly(≥65 years).Kaplan-Meier with log-rank test and Cox regression were used for survival *** In total 48682 individuals(52%males,average age 60.9±25.3 years)were *** cohort consisted of 12.0%children,29.5%adults,and 58.5%*** increased use of gastrostomies was observed during the study period,from 13.7/100000 to 22.3/100000 individuals(Pdoubled(about 800 to 1800/year),with a corresponding decrease in open gastrostomy(about 700 to 340/year).Laparoscopic gastrostomy increased more than ten-fold(about 20 to 240/year).Overall,PEG,open gastrostomy,and laparoscopic gastrostomy constituted 70.0%(n=34060),23.3%(n=11336),and 4.9%(n=2404),***-related mortality was 0.1%(n=44)overall(PEG:0.05%,open:0.24%,laparoscopic:0.04%).The overall 30-d mortality rate was 10.0%(PEG:9.8%,open:12.4%,laparoscopic:1.7%)and decreased from 11.6%in 1998-2009 vs 8.5%in 2010-2019(Pd ten-year survival rates for children,adults,and elderly were 93.7%,67.5%,a

关键词： Gastrostomy Percutaneous endoscopic gastrostomy dysphagia Enteral nutrition Long-term Survival Complication

Porphyrinic Acceptors forFullerene-Free MolecularPhotovoltaics

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CCS Chemistry 2024年第2期6卷 276-296页

作者： Jorge Labella Juan Laforga-martin Tomás Torres department of Organic Chemistry Universidad Aut´onoma de Madrid28049 Madrid Institute for Advanced Research in Chemical Sciences Universidad Aut´onoma de MadridMadrid IMdEA—Nanociencia 28049 Madrid

Over the past few years,the development of nonfullerene acceptors(NFAs)has become a prominent focus in both organic and perovskite solar cell(OSCs and PSCs,respectively)research *** this context,porphyrinoids,compounds structurally related to porphyrins,have emerged as promising solar cell *** contrast to the widely used fullerene acceptors,porphyrinoids exhibit strong,broad absorption properties across the UV–vis/NIR spectrum,which can be easily tuned through chemical ***,they can be prepared and derivatized using cost-effective and straightforward methodologies,allowing for convenient adjustments in thin-film morphology,processability,supramolecular organization,and energy ***,these compounds offer higher thermal and photochemical stability,resulting in longer device lifetimes compared to their fullerene-based *** this review,we outline the utilization of porphyrinoids as NFAs in OSCs and PSCs,discussing essential aspects such as design guidelines,molecular properties,and device *** goal is to inspire and further promote the development of n-type porphyrinoids,which have not yet fully unleashed their potential.

关键词： fullerene-free molecular photovoltaics nonfullerene acceptors porphyrinic acceptors n-type porphyrinoids organic and perovskite solar cells

Sustaining forest biodiversity:Exploring the effect of long-term natural disturbance dynamics on contemporary lichen communities in primary forest ecosystems

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Forest Ecosystems 2024年第4期11卷 556-567页

作者： Rhiannon Gloor Marek Svitok martin Mikolas Jenyk Hofmeister Josef Halda Pavel Janda Francesco Maria Sabatini Lucie Zemanova Arne Buechling daniel Kozak Matej Ferencik Michal Frankovic martin dusatko Miroslav Svoboda department of Forest Ecology Faculty of Forestry and Wood SciencesCzech University of Life Sciences PragueKamycka 129Praha 6–Suchdol16500Czech Republic Faculty of Ecology and Environmental Sciences Technical University in ZvolenT.G.Masaryka 2496001ZvolenSlovakia Institute of Botany Plant Science and Biodiversity CenterSlovak Academy of SciencesDúbravska cesta 984523BratislavaSlovakia PRALES Odtrnovie 56301322RosinaSlovakia Faculty of Science University of Hradec KraloveHradecka 1285Hradec KraloveⅢ50003Czech Republic BIOME–Biogeography and Macroecology Department of BiologicalGeological and Environmental Sciences(BIGEA)Alma Mater Studiorum-University of Bolognavia Irnerio 42BolognaItaly

In this era of biodiversity loss and climate change,quantifying the impacts of natural disturbance on forest communities is imperative to improve biodiversity conservation *** and epixylic lichens are effective forest quality bioindicators,as they are generally long-lived organisms supported by continuity of specific forest structures and their associated microclimatic ***,how lichen communities respond to the effects of fluctuating historical disturbances remains *** a dendrochronological approach,this study investigates how natural disturbance dynamics indirectly influence various lichen community metrics in some of Europe's best-preserved primary mixed-beech *** modelling revealed that natural historical disturbance processes have decades-long effects on forest structural attributes,which had both congruent and divergent impacts on lichen community richness and *** species richness indirectly benefited from both historical and recent higher-severity disturbances via increased standing dead tree basal area and canopy openness respectively-likely through the presence of both pioneer and late-successional species associated with these ***-listed species richness showed a dependence on habitat continuity(old trees),and increased with disturbance-related structures(standing dead trees)whilst simultaneously benefiting from periods without severe disturbance events(old trees and reduced deadwood volume).However,if the disturbance occurred over a century in the past,no substantial effect on forest structure was ***,while disturbance-mediated forest structures can promote overall richness,threatened species appear vulnerable to more severe disturbance events-a concern,as disturbances are predicted to intensify with climate ***,the high number of threatened species found reinforce the critical role of primary forest structural attributes for biodiversity ***

关键词： Mixed-beech forests Species richness Old-growth forests Carpathian mountains Biodiversity conservation dendroecology Fagus sylvatica

Identifying the validity domain of machine learning models in building energy systems

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Energy and AI 2024年第1期15卷 328-341页

作者： martin Rätz Patrick Henkel Phillip Stoffel Rita Streblow dirk Müller RWTH Aachen University E.ON Energy Research CenterInstitute for Energy Efficient Buildings and Indoor ClimateMathieustraβe 10Aachen52074Germany

The building sector significantly contributes to climate *** improve its carbon footprint,applications like model predictive control and predictive maintenance rely on system ***,the high modeling effort hinders practical *** learning models can significantly reduce this modeling *** ensure a machine learning model’s reliability in all operating states,it is essential to know its validity *** states outside the validity domain might lead to extrapolation,resulting in unpredictable *** paper addresses the challenge of identifying extrapolation in data-driven building energy system models and aims to raise knowledge about *** that,a novel approach is proposed that calibrates novelty detection algorithms towards the machine learning *** novelty detection algorithms are identified through a literature review and a benchmark test with 15 candidates.A subset of five algorithms is then evaluated on building energy ***,on two-dimensional data,displaying the results with a novel visualization *** on more complex multi-dimensional use *** methodology performs well,and the validity domain could be *** visualization allows for a profound analysis and an improved understanding of the fundamental effects behind a machine learning model’s validity domain and the extrapolation regimes.

关键词： Extrapolation detection Validity domain Novelty detection Machine learning Artificial neural network data-driven model predictive control Building energy systems