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Parallelization of frequency domain quantum gates:manipulation and distribution of frequency-entangled photon pairs generated by a 21 GHz silicon microresonator

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Advanced Photonics 2024年第3期6卷 60-69页

作者： Antoine Henry Dario A.Fioretto Lorenzo M.Procopio Stéphane Monfray Frédéric Boeuf Laurent Vivien Eric Cassan Carlos Alonzo-Ramos Kamel Bencheikh Isabelle Zaquine Nadia Belabas Institut Polytechnique de Paris LTCI Université Paris-Saclay CNRS Centre for Nanosciences and Nanotechnology Weizmann Institute of Science STMicroelectronics SAS

Harnessing the frequency dimension in integrated photonics offers key advantages in terms of scalability, noise resilience, parallelization, and compatibility with telecom multiplexing *** ring resonators have been used to generate frequency-entangled states through spontaneous four-wave mixing. However, state-of-the-art integrated resonators are limited by trade-offs among size,spectral separation, and efficient photon pair generation. We have developed silicon ring resonators with a footprint below 0.05 mm2providing more than 70 frequency channels separated by 21 GHz. We exploit the narrow frequency separation to parallelize and independently control 34 single qubit-gates with a single set of three off-the-shelf electro-optic devices. We fully characterize 17 frequency-bin maximally entangled qubit pairs by performing quantum state tomography. We demonstrate for the first time, we believe, a fully connected five-user quantum network in the frequency domain. These results are a step towards a generation of quantum circuits implemented with scalable silicon photonics technology, for applications in quantum computing and secure communications.

关键词： frequency domain integrated photonics quantum gates quantum networks

Visible light-driven photo remediation of hazardous cationic dye via Ce-doped WO_(3) nanostructures

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Journal of Rare Earths 2024年第5期42卷 869-878,I0003页

作者： Azra Haroon Kaseed Anwar Arham S.Ahmed Department of Physics Aligarh Muslim University202002AligarhIndia Interdisciplinary nanotechnology centre Aligarh Muslim University202002AligarhIndia

Ce-doped WO_(3) nanoparticles were successfully synthesized by the sol-gel method and characterized through advanced characterization *** high resolution transmission electron microscopy(HRTEM)and scanning electron microscopy(SEM)results show a reduction in the agglomeration of nanoparticles upon *** energy dispersive X-ray(EDX)analysis validates the existence of the Ce element in all the doped samples.X-ray photoelectron spectroscopy(XPS)and Raman spectra justify the presence of structural defects(oxygen vacancies)and successful formation of the monoclinic WO_(3) phase,*** Kubelka-Munk function indicates a decrease in band gap with doping,while photoluminescence(PL)spectra show intense visible and UV emissions,Significantly,all doped samples exhibit higher photocatalytic performance than pure WO_(3) nanoparticles,with the 6 wt%Ce-doped sample displaying the highest degradation *** with Ce can help to increase the surface area of WO_(3),thereby improving its photoactivity,Moreover,a correlation between PL and photocatalysis is established in the light of oxygen vacancies suggesting a direct dependence of high photocatalytic activity on strong PL signals of WO_(3) *** experiments further reveal that the degradation process is primarily driven by active species,providing insight into a plausible photocatalytic mechanism.

关键词： WO_(3) Rare-earth element Environmental crisis Oxygen vacancies Luminescence Photocatalysis

Recent progress in carbonaceous materials based Z-scheme and Sscheme heterojunctions for photocatalytic clean energy generation

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新型炭材料(中英文) 2024年

作者： Sahil Rana Amit Kumar Wang Tong-tong Gaurav Sharma Pooja Dhiman Alberto García-Penas Interdisciplinary and Innovate Research Xi'an University of Architecture and Technology Departamento de Ciencia e Ingeniería de Materiales e Ingeniería Química (IAAB) Universidad Carlos III de Madrid International Research centre of nanotechnology for Himalayan sustainability (IRCNHS) Shoolini University

Carbonaceous materials including carbon nanotubes/nanofibers, graphene, graphene oxide, reduced graphene oxide,graphyne, graphdiyne, carbon quantum dots and fullerenes have gained considerable attention in the recent years for their unique properties such as high conductivity, excellent stability and biocompatibility. The integration of these carbonaceous materials into Zscheme and S-scheme heterojunctions has emerged as a transformative strategy to enhance the photocatalytic efficiency for energy conversion applications. This review delves into the fundamental principles of clean energy generation such as photocatalytic H2generation and CO2reduction, elucidating their respective mechanisms and advantages. Furthermore, various types of carbonaceous materials, their synthesis and construction of Z-scheme and S-scheme heterojunctions are discussed emphasizing their role in promoting charge separation, reducing recombination losses and extending the spectral response range. With the focus on solar fuel production,the recent advancements in carbonaceous based Z-scheme and S-scheme heterojunctions are discussed and summarized for photocatalytic H2generation and CO2reduction. Lastly, the current bottlenecks and challenges in the field of carbonaceous based photocatalysts are discussed with the valuable insights for future development in this particular field.

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A decomposition of light’s spin angular momentum density

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Light(Science & Applications) 2024年第8期13卷 1578-1589页

作者： Alex J.Vernon Sebastian Golat Claire Rigouzzo Eugene A.Lim Francisco J.Rodríguez-Fortuño Department of Physics King’s College LondonStrandLondon WC2R 2LSUK London centre for nanotechnology LondonUK

Light carries intrinsic spin angular momentum(SAM)when the electric or magnetic field vector rotates over time.A familiar vector equation calculates the direction of light’s SAM density using the right-hand rule with reference to the electric and magnetic polarisation *** Maxwell’s equations,this vector equation can be decomposed into a sum of two distinct terms,akin to the well-known Poynting vector decomposition into orbital and spin *** present the first general study of this spin decomposition,showing that the two terms,which we call canonical and Poynting spin,are chiral analogies to the canonical and spin momenta of light in its interaction with *** canonical momentum,canonical spin is directly *** canonical and Poynting spin incorporate spatial variation of the electric and magnetic fields and are influenced by optical *** decomposition allows us to show that a linearly polarised vortex beam,which has no total SAM,can nevertheless exert longitudinal chiral pressure due to equal and opposite canonical and Poynting spins.

关键词： canonical momentum angular

Defect mediated losses and degradation of perovskite solar cells:Origin impacts and reliable characterization techniques

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Journal of Energy Chemistry 2024年第7期94卷 217-253页

作者： Himangshu Baishy Ramkrishna Das Adhikari Mayur Jagdishbhai Patel Deepak Yadav Tapashi Sarmah Mizanur Alam Manab Kalita Parameswar Krishnan lyer centre for nanotechnology Indian Institute of Technology GuwahatiGuwahati 781039AssamIndia Department of Chemistry Indian Institute ofTechnology GuwahatGuwahati739AssamIndi

The rapid advancement of halide-based hybrid perovskite materials has garnered significant research attention,particularly in the domain of photovoltaic *** to their exceptional optoelec-tronic properties,they demonstrated power conversion efficiency(PcE)of over 25%in single junction solar *** the notable progress in PCE over the past decade,the inherent high defect density pre-senting in perovskite materials gives rise to several loss mechanisms and associated ion migration in per-ovskite solar cells(PsCs)during operational *** factors collectively contribute to a significant stability challenge in PsCs,placing their longevity far behind for *** numerous reports have explored defects,ion migration,and their impacts on device performance,a com-prehensive correlation between the types of defects and the degradation kinetics of perovskite materials and PsCs has been *** this context,this review aims to provide a comprehensive overview of the origins of defects and ion migration,emphasizing their correlation with the degradation kinetics of per-ovskite materials and PsCs,leveraging reliable characterization ***,these charac-terization techniques are intended to comprehend loss mechanisms by different passivation approaches to enhance the durability and PCE of PSCs.

关键词： Perovskite solar cells Defects lon migration Degradation Stability

A Systematic Analysis of Systems Approach and Flood Risk Management Research:Trends,Gaps,and Opportunities

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International Journal of Disaster Risk Science 2024年第1期15卷 45-57页

作者： Lum Sonita Awah Johanes Amate Belle Yong Sebastian Nyam Israel Ropo Orimoloye Disaster Management Training and Education centre for Africa University of the Free StateBloemfontein 9300South Africa School of Environment Geographyand SustainabilityWestern Michigan UniversityKalamazooMI 49008USA

Flooding is a global threat,necessitating a comprehensive management *** to the complexity of managing flood hazards and risks,researchers have advocated for holistic,comprehensive,and integrated *** study,employing a systems thinking perspective,assessed global flood risk management research trends,gaps,and opportunities using132 published documents in BibTeX format.A systematic review of downloaded documents from the Scopus and Web of Science databases revealed slow progress of approximately 11.61% annual growth in applying systems thinking and its concomitant approaches to understanding global flood risk management over the past two decades compared to other fields like water resource management and business management systems.A significant gap exists in the application of systems thinking methodologies to flood risk management research between developed and developing countries,particularly in Africa,highlighting the urgency of reoriented research and policy *** application gaps of the study methodology are linked to challenges outlined in existing literature,such as issues related to technical expertise and resource *** study advocates a shift from linear to holistic approaches in flood risk management,aligned with the Sendai Framework for Disaster Risk Reduction 2015-2023 and the Sustainable Development *** among researchers,institutions,and countries is essential to address this global challenge effectively.

关键词： Flood risk management research Gaps and opportunities Global trends in flood research Systematic review.Systems thinking

Tensile deformation of fine-grained Mg at 4K,78K and 298K

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Journal of Magnesium and Alloys 2024年第6期12卷 2534-2556页

作者： M.Walag A.Kula P.Noga T.Tokarski G.Cios M.Niewczas AGH University of Krakow Faculty of Non-Ferrous MetalsKrakowPoland AGH University of Krakow Academic Centre for Materials and NanotechnologyKrakowPoland Materials Science and Engineering McMaster UniversityHamiltonCanada

The impact of grain size, ranging from 0.9 μm to 9 μm, on the mechanical properties of commercially pure Mg is investigated at temperatures of 4K, 78K, and 298K. The mechanisms governing plastic flow are influenced by both grain size and temperature. At 4K and 78K, dominant deformation modes in Mg involve dislocation glide and extension twinning, regardless of grain size. The interactions between basal and non-basal dislocations and dislocations with grain boundaries promote an unusually high rate of work hardening in the plastic regime, leading to premature failure. The yield stress follows the Hall-Petch relationship σy~ k/√d, with the slope k increasing with decreasing temperature. At 298K, in addition to dislocation glide and twinning, grain boundary sliding(GBS) becomes significant in samples with grain sizes below 3 μm, considerably enhancing the material's deformability. GBS activation provides an additional recovery mechanism for dislocations accumulating at grain boundaries, facilitating their absorption during sliding and rotation. Analysis of σ Θ relationship suggests that the basal slip is the dominant dislocation mode in Mg at 298K. Decreasing grain size suppresses dislocation activity and twinning and increases GBS, resulting in lower Θ and σ Θ values. Suppressing conventional deformation modes coupled with enhanced GBS yields stress softening, breaking down the Hall-Petch relationship in Mg below 3 μm grain size, leading to an inverse Hall-Petch behaviour. The work reports new data on the strength, ductility, work hardening and fracture behaviour, and their variations with Mg grain size across different temperature regimes.

关键词： Polycrystalline Mg Mechanical properties Deformation mechanisms Work-hardening Texture evolution Cryogenic temperatures Hall-Petch relationship

Molecular Engineering of Naphthalimide Methylcyclohexane Luminogen:Unraveling J^(*)-Aggregation Pattern and Sensing Melamine in Aqueous Media

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CCS Chemistry 2024年第4期6卷 923-931页

作者： Kavita Narang Parameswar Krishnan Iyer Department of Chemistry Indian Institute of Technology GuwahatiGuwahati 781039Assam centre for nanotechnology Indian Institute of Technology GuwahatiGuwahati 781039Assam

Naphthalimide methylcyclohexane(NMICY)luminogen that features molecular conformation-directed aggregation-induced emission was prepared,and its pure equatorial conformer was isolated and wellcharacterized via various techniques,including single-crystal X-ray diffraction(SC-XRD)*** NMICY,the methyl cyclohexane substituent adapted the most stable chair conformation,preventing intermolecularπ-πinteractions among the naphthalimide *** analysis of the self-assembly behavior indicated that an uncommon J^(*)-aggregation pattern was predominant for NMICY that exhibited∼450 nm emission in crystal as well as in the aggregated state[λmax=455 nm,фPL=23.22%,fw=99.9%in water or water-dimethylformamide mixture].NMICY self-assembled into cube-shaped 2D-nanoarchitecture as characterized by fieldemission scanning electron microscopy,atomic force microscopy,and dynamic light scattering(Zavg=143 nm,∼20 nm height)studies while also displaying unique optical properties in the aggregated *** supramolecular self-assembly and aggregated state structure-property relationship in aqueous media of NMICY were optimized,and a facile strategy for the detection of melamine in milk and an aqueous solution of milk powder is reported with a limit of detection value of 0.184 ppm(milk)and 0.101 ppm(milk powder),achieved via the rare acceptor-excited photoinduced electron transfer ***,a smartphone-based,portable,and uncomplicated sensing platform was developed that simplifies the melamine detection process.

关键词： conformational isomers J^(*)-aggregation aggregation-induced emission supramolecular assembly melamine detection acceptor-excited photoinduced electron transfer mechanism

The electricity,industrial,and agricultural sectors under changing climate:Adaptation and mitigation in China

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National Science Open 2024年第1期3卷 100-146页

作者： Kaixuan Wang Linqi Sun Jiatai Wang Lirong Liu centre for Environment and sustainability University of SurreyGuildford GU27XHUK

Climate change is a pressing global concern with far-reaching consequences that vary across *** the adverse impacts of climate change on various sectors is a challenging issue faced by countries worldwide,including *** is imperative for China to address climate change to foster sustainable development and make meaningful contributions to global climate mitigation *** paper presented a comprehensive analysis of the impacts of climate change on the electricity,agriculture,and industry sectors,which together account for over 80%of the greenhouse gas(GHG)emissions in ***,the strategies employed by these sectors to address climate change were reviewed,and potential future developments were *** review article could shine light on climate change practices and evidence-based policies aimed at addressing climate-related challenges across various sectors in China.

关键词： Climate change Electricity sector Industrial sector Agricultural sector Mitigation Adaptation.