Three bench-stable difluoromethylene phosphonate hydrazones were prepared from simple diethyl(difluoromethyl)phosphonate within two steps in good yields. The [3 + 2] cycloaddition reaction of these diazo precursors wi...Three bench-stable difluoromethylene phosphonate hydrazones were prepared from simple diethyl(difluoromethyl)phosphonate within two steps in good yields. The [3 + 2] cycloaddition reaction of these diazo precursors with aryl diazonium salts has been accomplished under metal-free conditions with exclusive regioselectivity. This transformation provides practical access to a broad panel of 2-aryl-2 H-tetrazol-5-yl difluoromethylene phosphonates, including the corresponding derivatives of amino acid(phenylalanine) and drug cores(Pomalidomide and Lapatinib fragment).展开更多
Polyester(PET) was pre-activated by atmospheric air plasma and coated by various inorganic oxide nanoparticles(MOx) such as titanium dioxide(TiO2), zinc oxide(ZnO), and silicon oxide(SiO2), using poly(vinylidene fluor...Polyester(PET) was pre-activated by atmospheric air plasma and coated by various inorganic oxide nanoparticles(MOx) such as titanium dioxide(TiO2), zinc oxide(ZnO), and silicon oxide(SiO2), using poly(vinylidene fluoride)(PVDF) and chitosan(CT) as binders. The resulting PET-PVDF-MOx-CT composites were thermally compressed and then characterized by scanning electron microscopy, Fourier infrared spectroscopy, thermal gravimetric analysis, and flame retardancy(FR) ability tests. PET modifications resulted in more thermally stable and less harmful composites with weaker hazardous gas release. This was explained in terms of structure compaction that blocks pyrolysis gas emissions.CT incorporation was found to reduce the material susceptibility to oxidation. This judicious procedure also allowed improving flame retardancy ability, by lengthening the combustion delay and slowing the flame propagation. Chitosan also turned out to contribute to a possible synergy with the other polymers present in the synthesized materials. These results provide valuable data that allow understanding the FR phenomena and envisaging low-cost high FR materials from biodegradable raw materials.展开更多
Atomic force microscopy （AFM） and power-dependent micro-photoluminescence （μ-PL） spectroscopy are used to study the structure and exciton energy states in InAs quantum dots （QDs） grown on an In0.35Ga0.65As temp...Atomic force microscopy （AFM） and power-dependent micro-photoluminescence （μ-PL） spectroscopy are used to study the structure and exciton energy states in InAs quantum dots （QDs） grown on an In0.35Ga0.65As template on GaAs （311）B. The In0.35Ga0.65As template, consisting of a two-dimensionally modulated layer of closely packed connected cells, has a remarkable effect on the optical properties of the IhAs QDs. By comparing the emission spectra of the samples without and with InAs QDs and the work carried out by Gong et al. [J. Cryst. Growth 251 （2003） 150; Appl. Phys. Lett. 81 （2002） 3254] we conclude that the existence of the In0.35Ga0.65As template enhances the photo-absorption and therefore the exeiton emission from the QDs due to efficient exciton transfer from the template into the QDs. Furthermore, the PL emission from the QDs dearly reveals four discrete energy levels, S, P, D, and F with increasing excitation power.展开更多
Ultrafine particles represent a growing concern in the public health community but their precise role in many illnesses is still unknown. This lack of knowledge is related to the experimental difficulty in linking the...Ultrafine particles represent a growing concern in the public health community but their precise role in many illnesses is still unknown. This lack of knowledge is related to the experimental difficulty in linking their biological effects to their multiple properties, which are important determinants of toxicity. Our aim is to propose an interdisciplinary approach to study fine(FP) and ultrafine(UFP) particles, generated in a controlled manner using a mini CAST(Combustion Aerosol Standard) soot generator used with two different operating conditions(CAST1 and CAST3). The chemical characterization was performed by an untargeted analysis using ultra-high resolution mass spectrometry. In conjunction with this approach, subsequent analysis by gas chromatography–mass spectrometry(GC–MS) was performed to identify polycyclic aromatic hydrocarbons(PAH). CAST1 enabled the generation of FP with a predominance of small PAH molecules, and CAST3 enabled the generation of UFP, which presented higher numbers of carbon atoms corresponding to larger PAH molecules. Healthy normal human bronchial epithelial(NHBE) cells differentiated at the air-liquid interface(ALI) were directly exposed to these freshly emitted FP and UFP. Expression of MUC5AC, FOXJ1, OCLN and ZOI as well as microscopic observation confirmed the ciliated pseudostratified epithelial phenotype. Study of the mass deposition efficiency revealed a difference between the two operating conditions, probably due to the morphological differences between the two categories of particles. We demonstrated that only NHBE cells exposed to CAST3 particles induced upregulation in the gene expression of IL-8 and NQO1. This approach offers new perspectives to study FP and UFP with stable and controlled properties.展开更多
The separation of rare earth elements using diatomite M45 from aqueous solutions was studied.The experimental isotherms for the adsorption of trivalent lanthanum,cerium,and neodymium cations on this adsorbent were qua...The separation of rare earth elements using diatomite M45 from aqueous solutions was studied.The experimental isotherms for the adsorption of trivalent lanthanum,cerium,and neodymium cations on this adsorbent were quantified under strongly acidic conditions(pH 2)at 298-328 K.The adsorption equilibria of these earth elements were analyzed using two statistical physics models(homogeneous and heterogeneous monolayer models).The results show that the adsorption of these ions implies a multiionic mechanism,which is exothermic.Si-containing functional groups are responsible for the adsorption of these rare-earth elements on the diatomite surface.A heterogeneous statistical physics model confirms that two Si-based functional groups participate in the separation of these cations.The calculated adsorption capacities at saturation follow the order:neodymium>cerium>lanthanum.Calculated interaction energies range from 28600 to 40100 J/mol,indicating physical adsorption on diatomite M45.This study demonstrates that diatomite M45 is a promising separation medium that can be used for the recovery of REEs dissolved in aqueous solutions via adsorption.展开更多
The trifluoromethylthio group （SCF3） is a fluorine chemotype that has experienced a strong acceleration of in- terest in the recent years. It is particularly true of the construction of new fluorinated architectures...The trifluoromethylthio group （SCF3） is a fluorine chemotype that has experienced a strong acceleration of in- terest in the recent years. It is particularly true of the construction of new fluorinated architectures by electrophilic trifluoromethylthiolation. The spread of knowledge was already very active in this research domain in the sixties; however, gaseous and highly toxic trifluoromethanesulfenyl chloride （CF3SC1） was the only reagent available at that time. Nowadays, one really can speak of a revival in the field thanks to the rapid development of a wide pano- ply of reagents that are stable and easy to handle. This review provides a historical perspective of the development of shelf-stable electrophilic trifluoromethylthiolation reagents.展开更多
Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intri...Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intrinsic quantum efficiency (QE) and the stability oflight emitters. For this reason, it is broadly accepted that with the advent of highly efficient (QE close to 1) and stable emitters, thefundamental research phase of SSL is coming to an end. In this study, we demonstrate a very large improvement in SSL emission (above70-fold directional enhancement for p-polarized emission and 60-fold enhancement for unpolarized emission) using nanophotonicstructures. This is attained by coupling emitters with very high QE to collective plasmonic resonances in periodic arrays of aluminumnanoantennas. Our results open a new path for fundamental and applied research in SSL in which plasmonic nanostructures are able tomold the spectral and angular distribution of the emission with unprecedented precision.展开更多
Integrated circuit technologies are enabling intelligent,chip-based,optical packet switch matrices.Rapid real-time reconfigurability at the photonic layer using integrated circuit technologies is expected to enable co...Integrated circuit technologies are enabling intelligent,chip-based,optical packet switch matrices.Rapid real-time reconfigurability at the photonic layer using integrated circuit technologies is expected to enable cost-effective,energy-efficient,and transparent data communications.InP integrated photonic circuits offer high-performance amplifiers,switches,modulators,detectors,and de/multiplexers in the same wafer-scale processes.The complexity of these circuits has been transformed as the process technologies have matured,enabling component counts to increase to many hundreds per chip.Active–passive monolithic integration has enabled switching matrices with up to 480 components,connecting 16 inputs to 16 outputs.Integrated switching matrices route data streams of hundreds of gigabits per second.Multi-path and packet time-scale switching have been demonstrated in the laboratory to route between multiple fibre connections.Wavelength-granularity routing and monitoring is realised inside the chip.In this paper,we review the current status in InP integrated photonics for optical switch matrices,paying particular attention to the additional on-chip functions that become feasible with active component integration.We highlight the opportunities for introducing intelligence at the physical layer and explore the requirements and opportunities for cost-effective,scalable switching.展开更多
InP integrated photonics has become a critical enabler for modern telecommunications, and is poised to revolutionize data communications, precision metrology, spectrometry, and imaging. The possibility to integrate hi...InP integrated photonics has become a critical enabler for modern telecommunications, and is poised to revolutionize data communications, precision metrology, spectrometry, and imaging. The possibility to integrate high-performance amplifiers, lasers, modulators, and detectors in combination with interferometers within one chip is enabling game-changing performance advances, energy savings, and cost reductions. Generic integration accelerates progress through the separation of applications from a common technology development. In this paper, we review the current status in In P integrated photonics and the efforts to integrate the next generation of high-performance functionality on a common substrate using the generic methodology.展开更多
Light-emitting diodes(LEDs)are driving a shift toward energy-efficient illumination.Nonetheless,modifying the emission intensities,colors and directionalities of LEDs in specific ways remains a challenge often tackled...Light-emitting diodes(LEDs)are driving a shift toward energy-efficient illumination.Nonetheless,modifying the emission intensities,colors and directionalities of LEDs in specific ways remains a challenge often tackled by incorporating secondary optical components.Metallic nanostructures supporting plasmonic resonances are an interesting alternative to this approach due to their strong light–matter interaction,which facilitates control over light emission without requiring external secondary optical components.This review discusses new methods that enhance the efficiencies of LEDs using nanostructured metals.This is an emerging field that incorporates physics,materials science,device technology and industry.First,we provide a general overview of state-of-the-art LED lighting,discussing the main characteristics required of both quantum wells and color converters to efficiently generate white light.Then,we discuss the main challenges in this field as well as the potential of metallic nanostructures to circumvent them.We review several of the most relevant demonstrations of LEDs in combination with metallic nanostructures,which have resulted in light-emitting devices with improved performance.We also highlight a few recent studies in applied plasmonics that,although exploratory and eminently fundamental,may lead to new solutions in illumination.展开更多
In this study,seven pretreatment methods for chromium speciation in tanned leather were evaluated:acidic miner‑alization,ethylenediaminetetraacetic acid(EDTA)extraction,diethylenetriaminepentaacetic acid(DTPA)extracti...In this study,seven pretreatment methods for chromium speciation in tanned leather were evaluated:acidic miner‑alization,ethylenediaminetetraacetic acid(EDTA)extraction,diethylenetriaminepentaacetic acid(DTPA)extraction,alkaline extraction(NH 4 OH),ammonium nitrate extraction(NH 4 NO 3),water extraction,and phosphate buffer extrac‑tion.Acidic mineralization permitted the decomposition of the organic matter and ensured the complete digestion of leathers,giving access to the total content of chromium in each sample using inductively coupled plasma‑atomic emission spectrometry(ICP‑AES).From all the extractant media tested,EDTA proved to be the most efficient,allowing the extraction of Cr(VI)and Cr(III)as a Cr(III)‑EDTA complex,quantitatively.Method validation is presented for EDTA extraction and direct mineralization.For the EDTA extraction,method detection limit(MDL)and method quantifica‑tion limit(MQL)for total Cr in leather were 3.4 ppb and 11.2 ppb(µg of total Cr per L of extraction solution),respec‑tively.Due to the lack of leather certified reference materials(CRMs)for Cr(VI),accuracy was evaluated by spiking leather samples with a Cr(VI)solution.The spike recovery of EDTA microwave assisted extraction ranged from 91.0 to 108.6%.Interday precision was also evaluated and all variation coefficients were below 5%,for both mineralization and EDTA extraction.This article provides an efficient procedure to extract quantitatively chromium from leather,while maintaining the speciation,which can be further followed by ion chromatography‑inductively coupled plasma‑mass spectrometry(IC‑ICP‑MS).展开更多
We report, for the first time to our knowledge, an on-chip mode-locked laser diode(OCMLLD) that employs multimode interference reflectors to eliminate the need of facet mirrors to form the cavity. The result is an OCM...We report, for the first time to our knowledge, an on-chip mode-locked laser diode(OCMLLD) that employs multimode interference reflectors to eliminate the need of facet mirrors to form the cavity. The result is an OCMLLD that does not require cleaved facets to operate, enabling us to locate this OCMLLD at any location within the photonic chip. This OCMLLD provides a simple source of optical pulses that can be inserted within a photonic integrated circuit chip for subsequent photonic signal processing operations within the chip(modulation, optical filtering, pulse rate multiplication, and so on). The device was designed using standardized building blocks of a generic active/passive In P technology platform, fabricated in a multi-project wafer run, and achieved mode-locking operation at its fundamental frequency, given the uncertainty at the design step of the optical length of these mirrors, critical to achieve colliding pulse mode-locked operation.展开更多
Hydrosilylation is one of the most important reactions in synthetic chemistry and ranks as a fundamental method to access organosilicon compounds in industrial and academic processes.However,the enantioselective const...Hydrosilylation is one of the most important reactions in synthetic chemistry and ranks as a fundamental method to access organosilicon compounds in industrial and academic processes.However,the enantioselective construction of chiral-at-silicon compounds via catalytic asymmetric hydrosilylation remained limited and difficult.Here we report a highly enantioselective hydrosilylation of ynones,a type of carbonyl-activated alkynes,using a palladium catalyst with a chiral binaphthyl phosphoramidite ligand.The stereospecific hydrosilylation of ynones affords a series of silicon-stereogenic silylenones with up to 94%yield,>20:1 regioselectivity and 98:2 enantioselectivity.The density functional theory(DFT)calculations were conducted to elucidate the reaction mechanism and origin of high degree of stereoselectivity,in which the powerful potential of aromatic interaction in this reaction is highlighted by the multiple C–H-πinteraction and aromatic cavity-oriented enantioselectivitydetermining step during desymmetric functionalization of Si–H bond.展开更多
In the present work,a comparative study of analytical methods for the simultaneous and quantitative determination of trivalent and hexavalent chromium is presented.For the analysis by ion chromatography-inductively co...In the present work,a comparative study of analytical methods for the simultaneous and quantitative determination of trivalent and hexavalent chromium is presented.For the analysis by ion chromatography-inductively coupled plasma-mass spectrometry,two different columns were tested,as well as different mobile phases and different pH of the samples.The optimized analytical method permitted the separation of Cr(Ⅲ)and Cr(Ⅵ)using 75 mmol/L NH_(4)NO_(3)pH 3 as chromatographic eluent.The method was validated and applied to real samples,allowing the determination of both species simultaneously,even when there is a huge difference of concentration between Cr(Ⅲ)and Cr(Ⅵ).Limit of detection and limit of quantification for Cr(Ⅲ)were found to be 0.016 and 0.054μg/L(0.3 and 1.1μg/kg),respectively,and for Cr(Ⅵ)0.13 and 0.43μg/L(7 and 22μg/kg),respectively.Possible species interconversions were monitored through the use of chromium isotopic standards,which confirmed that the optimized methodology preserves chromium speciation during extraction and analysis.Fourier-transform ion cyclotron resonance-mass spectrometry permitted the structure elucidation of the complex formed during ethylenediaminetetraacetic acid extraction.展开更多
OpticallylabeledIM/FSKsignalsaretransmittedover50kmofSMFunderdifferentcompensationschemes.All-optical label swapping based on MZ-SOA and EAM is presented. Transmission followed by label swapping shows a 2dB overall po...OpticallylabeledIM/FSKsignalsaretransmittedover50kmofSMFunderdifferentcompensationschemes.All-optical label swapping based on MZ-SOA and EAM is presented. Transmission followed by label swapping shows a 2dB overall power penalty.展开更多
Photonic and plasmonic devices rely on nanoscale control of the local density of optical states(LDOS)in dielectric and metallic environments.The tremendous progress in designing and tailoring the electric LDOS of nano...Photonic and plasmonic devices rely on nanoscale control of the local density of optical states(LDOS)in dielectric and metallic environments.The tremendous progress in designing and tailoring the electric LDOS of nano-resonators requires an investigation tool that is able to access the detailed features of the optical localized resonant modes with deep-subwavelength spatial resolution.This scenario has motivated the development of different nanoscale imaging techniques.Here,we prove that a technique involving the combination of scanning near-field optical microscopy with resonant scattering spectroscopy enables imaging the electric LDOS in nano-resonators with outstanding spatial resolution(λ/19)by means of a pure optical method based on light scattering.Using this technique,we investigate the properties of photonic crystal nanocavities,demonstrating that the resonant modes appear as characteristic Fano line shapes,which arise from interference.Therefore,by monitoring the spatial variation of the Fano line shape,we locally measure the phase modulation of the resonant modes without the need of external heterodyne detection.This novel,deep-subwavelength imaging method allows us to access both the intensity and the phase modulation of localized electric fields.Finally,this technique could be implemented on any type of platform,being particularly appealing for those based on non-optically active material,such as silicon,glass,polymers,or metals.展开更多
We present a theoretical investigation of THz long-range surface plasmon polaritons propagating on thin layers of InSb.The metallic behavior of doped semiconductors at THz frequencies allows the excitation of surface ...We present a theoretical investigation of THz long-range surface plasmon polaritons propagating on thin layers of InSb.The metallic behavior of doped semiconductors at THz frequencies allows the excitation of surface plasmon polaritons with propagation and confinement lengths that can be actively controlled.This control is achieved by acting on the free carrier density,which can be realized by changing the temperature of InSb.展开更多
基金supported by the National Natural Science Foundation of China (Nos.21772142,21901181 and 21961142015)the National Key Research and Development Program of China (No.2019YFA0905100)+1 种基金Tianjin Municipal Science & Technology Commission (No.19JCQNJC04700)the CNRS in France。
文摘Three bench-stable difluoromethylene phosphonate hydrazones were prepared from simple diethyl(difluoromethyl)phosphonate within two steps in good yields. The [3 + 2] cycloaddition reaction of these diazo precursors with aryl diazonium salts has been accomplished under metal-free conditions with exclusive regioselectivity. This transformation provides practical access to a broad panel of 2-aryl-2 H-tetrazol-5-yl difluoromethylene phosphonates, including the corresponding derivatives of amino acid(phenylalanine) and drug cores(Pomalidomide and Lapatinib fragment).
基金financially supported by the GEMTEX Laboratory-France
文摘Polyester(PET) was pre-activated by atmospheric air plasma and coated by various inorganic oxide nanoparticles(MOx) such as titanium dioxide(TiO2), zinc oxide(ZnO), and silicon oxide(SiO2), using poly(vinylidene fluoride)(PVDF) and chitosan(CT) as binders. The resulting PET-PVDF-MOx-CT composites were thermally compressed and then characterized by scanning electron microscopy, Fourier infrared spectroscopy, thermal gravimetric analysis, and flame retardancy(FR) ability tests. PET modifications resulted in more thermally stable and less harmful composites with weaker hazardous gas release. This was explained in terms of structure compaction that blocks pyrolysis gas emissions.CT incorporation was found to reduce the material susceptibility to oxidation. This judicious procedure also allowed improving flame retardancy ability, by lengthening the combustion delay and slowing the flame propagation. Chitosan also turned out to contribute to a possible synergy with the other polymers present in the synthesized materials. These results provide valuable data that allow understanding the FR phenomena and envisaging low-cost high FR materials from biodegradable raw materials.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10374018, 10321003, and 90401015, the Scientific Committee of Shanghai under Grant No 03DJ14001, and the Special Funds for Major State Basic Research Project of China under Grant No 2004CB619004.
文摘Atomic force microscopy （AFM） and power-dependent micro-photoluminescence （μ-PL） spectroscopy are used to study the structure and exciton energy states in InAs quantum dots （QDs） grown on an In0.35Ga0.65As template on GaAs （311）B. The In0.35Ga0.65As template, consisting of a two-dimensionally modulated layer of closely packed connected cells, has a remarkable effect on the optical properties of the IhAs QDs. By comparing the emission spectra of the samples without and with InAs QDs and the work carried out by Gong et al. [J. Cryst. Growth 251 （2003） 150; Appl. Phys. Lett. 81 （2002） 3254] we conclude that the existence of the In0.35Ga0.65As template enhances the photo-absorption and therefore the exeiton emission from the QDs due to efficient exciton transfer from the template into the QDs. Furthermore, the PL emission from the QDs dearly reveals four discrete energy levels, S, P, D, and F with increasing excitation power.
基金supported by ANSES (French Agency for Food,Environmental and Occupational Health and SafetyPUFBIO project,Grant number EST-2017-190)+5 种基金co-supported by the Regional Council of Normandy and the European Union in the framework of the ERDF-ESF (CellSTEM project)a PhD fellowship funded by ADEME(Agency for Ecological Transition)financed by the Labex SynOrg(ANR-11-LABX-0029)the European Regional Development Fund (ERDF HN0001343)Financial support from the National Fourier transform ion cyclotron resonance network (FR 3624 CNRS)the European Union’s Horizon 2020 Research Infrastructures program (grant agreement 731077).
文摘Ultrafine particles represent a growing concern in the public health community but their precise role in many illnesses is still unknown. This lack of knowledge is related to the experimental difficulty in linking their biological effects to their multiple properties, which are important determinants of toxicity. Our aim is to propose an interdisciplinary approach to study fine(FP) and ultrafine(UFP) particles, generated in a controlled manner using a mini CAST(Combustion Aerosol Standard) soot generator used with two different operating conditions(CAST1 and CAST3). The chemical characterization was performed by an untargeted analysis using ultra-high resolution mass spectrometry. In conjunction with this approach, subsequent analysis by gas chromatography–mass spectrometry(GC–MS) was performed to identify polycyclic aromatic hydrocarbons(PAH). CAST1 enabled the generation of FP with a predominance of small PAH molecules, and CAST3 enabled the generation of UFP, which presented higher numbers of carbon atoms corresponding to larger PAH molecules. Healthy normal human bronchial epithelial(NHBE) cells differentiated at the air-liquid interface(ALI) were directly exposed to these freshly emitted FP and UFP. Expression of MUC5AC, FOXJ1, OCLN and ZOI as well as microscopic observation confirmed the ciliated pseudostratified epithelial phenotype. Study of the mass deposition efficiency revealed a difference between the two operating conditions, probably due to the morphological differences between the two categories of particles. We demonstrated that only NHBE cells exposed to CAST3 particles induced upregulation in the gene expression of IL-8 and NQO1. This approach offers new perspectives to study FP and UFP with stable and controlled properties.
基金The Research Center for Advanced Materials Science (RCAMS)at King Khalid University,Saudi Arabia is acknowledged for funding this work under the grant number RCAMS/KKU/016-22。
文摘The separation of rare earth elements using diatomite M45 from aqueous solutions was studied.The experimental isotherms for the adsorption of trivalent lanthanum,cerium,and neodymium cations on this adsorbent were quantified under strongly acidic conditions(pH 2)at 298-328 K.The adsorption equilibria of these earth elements were analyzed using two statistical physics models(homogeneous and heterogeneous monolayer models).The results show that the adsorption of these ions implies a multiionic mechanism,which is exothermic.Si-containing functional groups are responsible for the adsorption of these rare-earth elements on the diatomite surface.A heterogeneous statistical physics model confirms that two Si-based functional groups participate in the separation of these cations.The calculated adsorption capacities at saturation follow the order:neodymium>cerium>lanthanum.Calculated interaction energies range from 28600 to 40100 J/mol,indicating physical adsorption on diatomite M45.This study demonstrates that diatomite M45 is a promising separation medium that can be used for the recovery of REEs dissolved in aqueous solutions via adsorption.
文摘The trifluoromethylthio group （SCF3） is a fluorine chemotype that has experienced a strong acceleration of in- terest in the recent years. It is particularly true of the construction of new fluorinated architectures by electrophilic trifluoromethylthiolation. The spread of knowledge was already very active in this research domain in the sixties; however, gaseous and highly toxic trifluoromethanesulfenyl chloride （CF3SC1） was the only reagent available at that time. Nowadays, one really can speak of a revival in the field thanks to the rapid development of a wide pano- ply of reagents that are stable and easy to handle. This review provides a historical perspective of the development of shelf-stable electrophilic trifluoromethylthiolation reagents.
基金This work is part of the research program of the Foundation for Fundamental Research on Matter(FOM),which is financially supported by the Netherlands Organization for Fundamental Research(NWO)It is also part of an industrial partnership program between Philips and FOM.It is supported by NanoNextNL of the Government of the Netherlands and 130 partners.
文摘Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intrinsic quantum efficiency (QE) and the stability oflight emitters. For this reason, it is broadly accepted that with the advent of highly efficient (QE close to 1) and stable emitters, thefundamental research phase of SSL is coming to an end. In this study, we demonstrate a very large improvement in SSL emission (above70-fold directional enhancement for p-polarized emission and 60-fold enhancement for unpolarized emission) using nanophotonicstructures. This is attained by coupling emitters with very high QE to collective plasmonic resonances in periodic arrays of aluminumnanoantennas. Our results open a new path for fundamental and applied research in SSL in which plasmonic nanostructures are able tomold the spectral and angular distribution of the emission with unprecedented precision.
基金The work has been supported by the Dutch technology foundation STW.
文摘Integrated circuit technologies are enabling intelligent,chip-based,optical packet switch matrices.Rapid real-time reconfigurability at the photonic layer using integrated circuit technologies is expected to enable cost-effective,energy-efficient,and transparent data communications.InP integrated photonic circuits offer high-performance amplifiers,switches,modulators,detectors,and de/multiplexers in the same wafer-scale processes.The complexity of these circuits has been transformed as the process technologies have matured,enabling component counts to increase to many hundreds per chip.Active–passive monolithic integration has enabled switching matrices with up to 480 components,connecting 16 inputs to 16 outputs.Integrated switching matrices route data streams of hundreds of gigabits per second.Multi-path and packet time-scale switching have been demonstrated in the laboratory to route between multiple fibre connections.Wavelength-granularity routing and monitoring is realised inside the chip.In this paper,we review the current status in InP integrated photonics for optical switch matrices,paying particular attention to the additional on-chip functions that become feasible with active component integration.We highlight the opportunities for introducing intelligence at the physical layer and explore the requirements and opportunities for cost-effective,scalable switching.
基金the EC FP7 project Paradigm, the Dutch Memphis project
文摘InP integrated photonics has become a critical enabler for modern telecommunications, and is poised to revolutionize data communications, precision metrology, spectrometry, and imaging. The possibility to integrate high-performance amplifiers, lasers, modulators, and detectors in combination with interferometers within one chip is enabling game-changing performance advances, energy savings, and cost reductions. Generic integration accelerates progress through the separation of applications from a common technology development. In this paper, we review the current status in In P integrated photonics and the efforts to integrate the next generation of high-performance functionality on a common substrate using the generic methodology.
基金supported by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek(NWO)through the project LEDMAP of the Technology Foundation STWthrough the Industrial Partnership Program Nanophotonics for Solid State Lighting between Philips and the Foundation for Fundamental Research on Matter FOMsupported by NanoNextNL of the Government of the Netherlands and 130 partners.
文摘Light-emitting diodes(LEDs)are driving a shift toward energy-efficient illumination.Nonetheless,modifying the emission intensities,colors and directionalities of LEDs in specific ways remains a challenge often tackled by incorporating secondary optical components.Metallic nanostructures supporting plasmonic resonances are an interesting alternative to this approach due to their strong light–matter interaction,which facilitates control over light emission without requiring external secondary optical components.This review discusses new methods that enhance the efficiencies of LEDs using nanostructured metals.This is an emerging field that incorporates physics,materials science,device technology and industry.First,we provide a general overview of state-of-the-art LED lighting,discussing the main characteristics required of both quantum wells and color converters to efficiently generate white light.Then,we discuss the main challenges in this field as well as the potential of metallic nanostructures to circumvent them.We review several of the most relevant demonstrations of LEDs in combination with metallic nanostructures,which have resulted in light-emitting devices with improved performance.We also highlight a few recent studies in applied plasmonics that,although exploratory and eminently fundamental,may lead to new solutions in illumination.
基金This work has been partially supported by University of Rouen Normandy,INSA Rouen Normandy,the Centre National de la Recherche Scientifique(CNRS),European Regional Development Fund(ERDF)NºHN0001343,Labex SynOrg(ANR‑11‑LABX‑0029)Carnot Institute I2C,the graduate school for research XL‑Chem(ANR‑18‑EURE‑0020 XL CHEM)+1 种基金Region Normandie,and Consejo Nacional de Ciencia y Tecnologia(CONACYT CVU 707668)IC instrument has been financed by RIN LabEx Milliflux Nº19E00566 and ICP/MS through Bioenairgy project(FEDER NºHN0001343).
文摘In this study,seven pretreatment methods for chromium speciation in tanned leather were evaluated:acidic miner‑alization,ethylenediaminetetraacetic acid(EDTA)extraction,diethylenetriaminepentaacetic acid(DTPA)extraction,alkaline extraction(NH 4 OH),ammonium nitrate extraction(NH 4 NO 3),water extraction,and phosphate buffer extrac‑tion.Acidic mineralization permitted the decomposition of the organic matter and ensured the complete digestion of leathers,giving access to the total content of chromium in each sample using inductively coupled plasma‑atomic emission spectrometry(ICP‑AES).From all the extractant media tested,EDTA proved to be the most efficient,allowing the extraction of Cr(VI)and Cr(III)as a Cr(III)‑EDTA complex,quantitatively.Method validation is presented for EDTA extraction and direct mineralization.For the EDTA extraction,method detection limit(MDL)and method quantifica‑tion limit(MQL)for total Cr in leather were 3.4 ppb and 11.2 ppb(µg of total Cr per L of extraction solution),respec‑tively.Due to the lack of leather certified reference materials(CRMs)for Cr(VI),accuracy was evaluated by spiking leather samples with a Cr(VI)solution.The spike recovery of EDTA microwave assisted extraction ranged from 91.0 to 108.6%.Interday precision was also evaluated and all variation coefficients were below 5%,for both mineralization and EDTA extraction.This article provides an efficient procedure to extract quantitatively chromium from leather,while maintaining the speciation,which can be further followed by ion chromatography‑inductively coupled plasma‑mass spectrometry(IC‑ICP‑MS).
基金support from the Spanish Ministerio de Economia y Competitividad Di DACTIC project (TEC201347753-C3-3-R)financial support from SENESCYT (National Secretary of Science, Technology, and Innovation, Quito, Ecuador) for the Ph.D. stage at Universidad Carlos Ⅲ de Madrid
文摘We report, for the first time to our knowledge, an on-chip mode-locked laser diode(OCMLLD) that employs multimode interference reflectors to eliminate the need of facet mirrors to form the cavity. The result is an OCMLLD that does not require cleaved facets to operate, enabling us to locate this OCMLLD at any location within the photonic chip. This OCMLLD provides a simple source of optical pulses that can be inserted within a photonic integrated circuit chip for subsequent photonic signal processing operations within the chip(modulation, optical filtering, pulse rate multiplication, and so on). The device was designed using standardized building blocks of a generic active/passive In P technology platform, fabricated in a multi-project wafer run, and achieved mode-locking operation at its fundamental frequency, given the uncertainty at the design step of the optical length of these mirrors, critical to achieve colliding pulse mode-locked operation.
基金This work was supported by the National Natural Science Foundation of China(21773051,22072035,21703051,21801056,21901056)Zhejiang Provincial Natural Science Foundation of China(LZ18B020001,LY18B020013,LQ19B040001).
文摘Hydrosilylation is one of the most important reactions in synthetic chemistry and ranks as a fundamental method to access organosilicon compounds in industrial and academic processes.However,the enantioselective construction of chiral-at-silicon compounds via catalytic asymmetric hydrosilylation remained limited and difficult.Here we report a highly enantioselective hydrosilylation of ynones,a type of carbonyl-activated alkynes,using a palladium catalyst with a chiral binaphthyl phosphoramidite ligand.The stereospecific hydrosilylation of ynones affords a series of silicon-stereogenic silylenones with up to 94%yield,>20:1 regioselectivity and 98:2 enantioselectivity.The density functional theory(DFT)calculations were conducted to elucidate the reaction mechanism and origin of high degree of stereoselectivity,in which the powerful potential of aromatic interaction in this reaction is highlighted by the multiple C–H-πinteraction and aromatic cavity-oriented enantioselectivitydetermining step during desymmetric functionalization of Si–H bond.
基金supported by University of Rouen Normandy,INSA Rouen Normandy,the Centre National de la Recherche Scientifque(CNRS),European Regional Development Fund(ERDF HN0001343)Labex Syn-Org(ANR-11-LABX-0029)+1 种基金Carnot Institute I2C,the graduate school for research XL-Chem(ANR-18-EURE-0020 XL CHEM)Region Normandie,and Consejo Nacional de Ciencia y Tecnologia(CONACYT CVU 707668).
文摘In the present work,a comparative study of analytical methods for the simultaneous and quantitative determination of trivalent and hexavalent chromium is presented.For the analysis by ion chromatography-inductively coupled plasma-mass spectrometry,two different columns were tested,as well as different mobile phases and different pH of the samples.The optimized analytical method permitted the separation of Cr(Ⅲ)and Cr(Ⅵ)using 75 mmol/L NH_(4)NO_(3)pH 3 as chromatographic eluent.The method was validated and applied to real samples,allowing the determination of both species simultaneously,even when there is a huge difference of concentration between Cr(Ⅲ)and Cr(Ⅵ).Limit of detection and limit of quantification for Cr(Ⅲ)were found to be 0.016 and 0.054μg/L(0.3 and 1.1μg/kg),respectively,and for Cr(Ⅵ)0.13 and 0.43μg/L(7 and 22μg/kg),respectively.Possible species interconversions were monitored through the use of chromium isotopic standards,which confirmed that the optimized methodology preserves chromium speciation during extraction and analysis.Fourier-transform ion cyclotron resonance-mass spectrometry permitted the structure elucidation of the complex formed during ethylenediaminetetraacetic acid extraction.
文摘OpticallylabeledIM/FSKsignalsaretransmittedover50kmofSMFunderdifferentcompensationschemes.All-optical label swapping based on MZ-SOA and EAM is presented. Transmission followed by label swapping shows a 2dB overall power penalty.
基金This work was supported by the FET project FP7618025 CARTOON and is part of the research program of the Foundation for Fundamental Research on Matter(FOM),which is financially supported by the Netherlands Organization for Scientific Research(NWO).
文摘Photonic and plasmonic devices rely on nanoscale control of the local density of optical states(LDOS)in dielectric and metallic environments.The tremendous progress in designing and tailoring the electric LDOS of nano-resonators requires an investigation tool that is able to access the detailed features of the optical localized resonant modes with deep-subwavelength spatial resolution.This scenario has motivated the development of different nanoscale imaging techniques.Here,we prove that a technique involving the combination of scanning near-field optical microscopy with resonant scattering spectroscopy enables imaging the electric LDOS in nano-resonators with outstanding spatial resolution(λ/19)by means of a pure optical method based on light scattering.Using this technique,we investigate the properties of photonic crystal nanocavities,demonstrating that the resonant modes appear as characteristic Fano line shapes,which arise from interference.Therefore,by monitoring the spatial variation of the Fano line shape,we locally measure the phase modulation of the resonant modes without the need of external heterodyne detection.This novel,deep-subwavelength imaging method allows us to access both the intensity and the phase modulation of localized electric fields.Finally,this technique could be implemented on any type of platform,being particularly appealing for those based on non-optically active material,such as silicon,glass,polymers,or metals.
基金supported by the European Research Council (ERC) (No. 259272)the European Commission Seventh Framework Programme (FP7) (No. FP7-224189)it is part of the research program of FOM, which is financially supported by NWO
文摘We present a theoretical investigation of THz long-range surface plasmon polaritons propagating on thin layers of InSb.The metallic behavior of doped semiconductors at THz frequencies allows the excitation of surface plasmon polaritons with propagation and confinement lengths that can be actively controlled.This control is achieved by acting on the free carrier density,which can be realized by changing the temperature of InSb.
