The collective flow for <sup>64</sup>Zn+<sup>27</sup>Al system is measured at intermediate energyby using a 4π multidetector array in conjunction with an array of Si telescopes.Theevents have ...The collective flow for <sup>64</sup>Zn+<sup>27</sup>Al system is measured at intermediate energyby using a 4π multidetector array in conjunction with an array of Si telescopes.Theevents have been sorted versus the impact parameter by means of global variables.Three methods of reaction plane determination are compared:sphericity tensor method,transverse momentum analysis,and azimuthal correlation method.For this system,thetransverse momentum analysis method is the best one.展开更多
Biochemical characterization was carried out on five mango varieties grown in Senegal, two of which are intended for export (Kent and Keitt) and three to local consumption, on the one hand, and to national marketing, ...Biochemical characterization was carried out on five mango varieties grown in Senegal, two of which are intended for export (Kent and Keitt) and three to local consumption, on the one hand, and to national marketing, on the other. It can be seen that the flavanols composition is between “0.74 ± 0.03 mg/100 g” to “4.70 ± 0.33 mg/100 g” and the total polyphenols composition is “265.83 ± 33.70 mg gallic acid/100 g” to “834.29 ± 25.78 mg gallic acid/100 g”. This analysis shows that the variety Bk is richer in polyphenols followed by the variety Dr then Knt and finally the lowest proportions are noted with the varieties Kt and SL. The analysis of antioxidant activity shows us percentages ranging from “4.16% ± 2.68% inhibition” to “50.21% ± 3.91% inhibition”. It was noted that the SL and Knt varieties give the highest inhibition percentages of “50.21 ± 3.91” and “33.97 ± 0.36” respectively. Variety Bk gives the lowest percentage followed by variety Kt. The Dr variety is the richest in flavonoids “11.75 ± 0.27” followed by the SL variety “11.27 ± 0.10” and the lowest composition is noted in the Knt variety “1.91 ± 0.04”. For total sugars, the most important contents are found in the varieties: Bk “12.71 ± 0.32 mg/100 g” followed by Dr “11.5 ± 0.33 mg/100 g” and SL “9.86 ± 0.06 mg/100 g”. This time the variety Kt stands out with also important proportions. For quantification, there is a slight difference in the values obtained for the different varieties studied. However, the highest values are observed in local varieties: “0.36 ± 0.06 g/100 g” for Bk and Dr followed by SL “0.31 ± 0.01 g/100 g”. The study of the mineral composition shows that the local varieties are the richest and the Knt variety is the poorest. The difference in composition noted within the same variety can be explained by the fact that some varieties have an advanced maturity compared to others.展开更多
In-plane heteroatom substitution of graphene is a promising strategy to modify its properties. The ability to dope graphene with electron-donor nitrogen heteroatoms is highly important for modulating electrical proper...In-plane heteroatom substitution of graphene is a promising strategy to modify its properties. The ability to dope graphene with electron-donor nitrogen heteroatoms is highly important for modulating electrical properties of graphene. Here we demonstrate a transfer-free method to directly grow large area quasi free-standing N-doped graphene bilayers on an insulating substrate （Si3N4）. Electron-bombardment heating under nitrogen flux results in simultaneous growth of N-doped graphene and a Si3N4 layer on the SiC surface. The decoupling of N-doped graphene from the substrate and the presence of Si3N4 are identified by X-ray photoemission spectroscopy and low-energy electron diffraction. The substitution of nitrogen atoms in the graphene planes was confirmed using high resolution X-ray photoemission spectroscopy which reveals several atomic configurations for the nitrogen atoms： Graphitic-like, pyridine-like, and pyrrolic- like. Furthermore, we demonstrated for the first time that N-doped graphene could be used to efficiently probe oxygen molecules via nitrogen atom defects.展开更多
This paper reviews and discusses recent developments in passively mode-locked vertical external cavity surface emitting lasers （ML-VECSELs） for short pulse generation at 1.55 gin. After comparing ML- VECSELs to othe...This paper reviews and discusses recent developments in passively mode-locked vertical external cavity surface emitting lasers （ML-VECSELs） for short pulse generation at 1.55 gin. After comparing ML- VECSELs to other options for short pulse generation, we reviewed the results of ML-VECSELs operating at telecommunication wavelength and point out the chal- lenges in achieving sub-picosecond operation from a ML- VECSEL at 1.55 gm. We described our recent work in the VECSELs and semiconductor saturable absorber mirrors （SESAMs）, their structure design, optimization and characterization, with the goal of moving the pulse width from picosecond to sub-picosecond.展开更多
In this study, the results show that total sugar contents depend on the variety and the position where the fruit (mango) has been harvested. This variation in total sugar contents is observed according to the followin...In this study, the results show that total sugar contents depend on the variety and the position where the fruit (mango) has been harvested. This variation in total sugar contents is observed according to the following varieties: the Bk (Boukodiekhal) variety (bottom position 45 mg/100 mL) then Bk (intermediate and bottom position 40 mg/100 mL) and with the Dr (Diourou) variety the content according to the intermediate position is 63 mg/100 mL while the content according to its bottom position is 56 mg/100 mL. The same is observed for variety Knt (Kent). For the variety factor, we see that the Dr and Sl (Sierra Leone) varieties are the richest in total sugars. Compared to the variation in reducing sugar content, the effect of position is less pronounced. Nevertheless, the statistical results show that the contents vary according to the varieties. There is a very significant variation in reducing sugar content between certain varieties. The variety Kt (Keitt) (45 mg/100 mL) is the richest in reducing sugars but compared to the lower position of the variety Bk, they are statistically identical. Variety Knt remains the poorest in reducing sugars 20 mg/ 100 mL.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
Light scattering by a two-dimensional photonic-crystal slab(PCS)can result in marked interference effects associated with Fano resonances.Such devices offer appealing alternatives to distributed Bragg reflectors and f...Light scattering by a two-dimensional photonic-crystal slab(PCS)can result in marked interference effects associated with Fano resonances.Such devices offer appealing alternatives to distributed Bragg reflectors and filters for various applications,such as optical wavelength and polarization filters,reflectors,semiconductor lasers,photodetectors,bio-sensors and non-linear optical components.Suspended PCS also have natural applications in the field of optomechanics,where the mechanical modes of a suspended slab interact via radiation pressure with the optical field of a high-finesse cavity.The reflectivity and transmission properties of a defect-free suspended PCS around normal incidence can be used to couple out-of-plane mechanical modes to an optical field by integrating it in a free-space cavity.Here we demonstrate the successful implementation of a PCS reflector on a high-tensile stress Si_(3)N_(4) nanomembrane.We illustrate the physical process underlying the high reflectivity by measuring the photonic-crystal band diagram.Moreover,we introduce a clear theoretical description of the membrane scattering properties in the presence of optical losses.By embedding the PCS inside a high-finesse cavity,we fully characterize its optical properties.The spectrally,angular-and polarization-resolved measurements demonstrate the wide tunability of the membrane’s reflectivity,from nearly 0 to 99.9470±0.0025%,and show that material absorption is not the main source of optical loss.Moreover,the cavity storage time demonstrated in this work exceeds the mechanical period of low-order mechanical drum modes.This so-called resolved-sideband condition is a prerequisite to achieve quantum control of the mechanical resonator with light.展开更多
文摘The collective flow for <sup>64</sup>Zn+<sup>27</sup>Al system is measured at intermediate energyby using a 4π multidetector array in conjunction with an array of Si telescopes.Theevents have been sorted versus the impact parameter by means of global variables.Three methods of reaction plane determination are compared:sphericity tensor method,transverse momentum analysis,and azimuthal correlation method.For this system,thetransverse momentum analysis method is the best one.
文摘Biochemical characterization was carried out on five mango varieties grown in Senegal, two of which are intended for export (Kent and Keitt) and three to local consumption, on the one hand, and to national marketing, on the other. It can be seen that the flavanols composition is between “0.74 ± 0.03 mg/100 g” to “4.70 ± 0.33 mg/100 g” and the total polyphenols composition is “265.83 ± 33.70 mg gallic acid/100 g” to “834.29 ± 25.78 mg gallic acid/100 g”. This analysis shows that the variety Bk is richer in polyphenols followed by the variety Dr then Knt and finally the lowest proportions are noted with the varieties Kt and SL. The analysis of antioxidant activity shows us percentages ranging from “4.16% ± 2.68% inhibition” to “50.21% ± 3.91% inhibition”. It was noted that the SL and Knt varieties give the highest inhibition percentages of “50.21 ± 3.91” and “33.97 ± 0.36” respectively. Variety Bk gives the lowest percentage followed by variety Kt. The Dr variety is the richest in flavonoids “11.75 ± 0.27” followed by the SL variety “11.27 ± 0.10” and the lowest composition is noted in the Knt variety “1.91 ± 0.04”. For total sugars, the most important contents are found in the varieties: Bk “12.71 ± 0.32 mg/100 g” followed by Dr “11.5 ± 0.33 mg/100 g” and SL “9.86 ± 0.06 mg/100 g”. This time the variety Kt stands out with also important proportions. For quantification, there is a slight difference in the values obtained for the different varieties studied. However, the highest values are observed in local varieties: “0.36 ± 0.06 g/100 g” for Bk and Dr followed by SL “0.31 ± 0.01 g/100 g”. The study of the mineral composition shows that the local varieties are the richest and the Knt variety is the poorest. The difference in composition noted within the same variety can be explained by the fact that some varieties have an advanced maturity compared to others.
文摘In-plane heteroatom substitution of graphene is a promising strategy to modify its properties. The ability to dope graphene with electron-donor nitrogen heteroatoms is highly important for modulating electrical properties of graphene. Here we demonstrate a transfer-free method to directly grow large area quasi free-standing N-doped graphene bilayers on an insulating substrate （Si3N4）. Electron-bombardment heating under nitrogen flux results in simultaneous growth of N-doped graphene and a Si3N4 layer on the SiC surface. The decoupling of N-doped graphene from the substrate and the presence of Si3N4 are identified by X-ray photoemission spectroscopy and low-energy electron diffraction. The substitution of nitrogen atoms in the graphene planes was confirmed using high resolution X-ray photoemission spectroscopy which reveals several atomic configurations for the nitrogen atoms： Graphitic-like, pyridine-like, and pyrrolic- like. Furthermore, we demonstrated for the first time that N-doped graphene could be used to efficiently probe oxygen molecules via nitrogen atom defects.
文摘This paper reviews and discusses recent developments in passively mode-locked vertical external cavity surface emitting lasers （ML-VECSELs） for short pulse generation at 1.55 gin. After comparing ML- VECSELs to other options for short pulse generation, we reviewed the results of ML-VECSELs operating at telecommunication wavelength and point out the chal- lenges in achieving sub-picosecond operation from a ML- VECSEL at 1.55 gm. We described our recent work in the VECSELs and semiconductor saturable absorber mirrors （SESAMs）, their structure design, optimization and characterization, with the goal of moving the pulse width from picosecond to sub-picosecond.
文摘In this study, the results show that total sugar contents depend on the variety and the position where the fruit (mango) has been harvested. This variation in total sugar contents is observed according to the following varieties: the Bk (Boukodiekhal) variety (bottom position 45 mg/100 mL) then Bk (intermediate and bottom position 40 mg/100 mL) and with the Dr (Diourou) variety the content according to the intermediate position is 63 mg/100 mL while the content according to its bottom position is 56 mg/100 mL. The same is observed for variety Knt (Kent). For the variety factor, we see that the Dr and Sl (Sierra Leone) varieties are the richest in total sugars. Compared to the variation in reducing sugar content, the effect of position is less pronounced. Nevertheless, the statistical results show that the contents vary according to the varieties. There is a very significant variation in reducing sugar content between certain varieties. The variety Kt (Keitt) (45 mg/100 mL) is the richest in reducing sugars but compared to the lower position of the variety Bk, they are statistically identical. Variety Knt remains the poorest in reducing sugars 20 mg/ 100 mL.
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funded by the Agence Nationale de la Recherche programs‘ANR-2011-BS04-029 MiNOToRe’and‘ANR-14-CE26-0002 QuNaT’the Marie Curie Initial Training Network‘cQOM’+2 种基金the DIM nano-K Ile-de-France program‘NanoMecAtom’supported by the Marie Sklodowska-Curie Individual Fellowship programsupported by a fellowship'Research in Paris'from the city of Paris.
文摘Light scattering by a two-dimensional photonic-crystal slab(PCS)can result in marked interference effects associated with Fano resonances.Such devices offer appealing alternatives to distributed Bragg reflectors and filters for various applications,such as optical wavelength and polarization filters,reflectors,semiconductor lasers,photodetectors,bio-sensors and non-linear optical components.Suspended PCS also have natural applications in the field of optomechanics,where the mechanical modes of a suspended slab interact via radiation pressure with the optical field of a high-finesse cavity.The reflectivity and transmission properties of a defect-free suspended PCS around normal incidence can be used to couple out-of-plane mechanical modes to an optical field by integrating it in a free-space cavity.Here we demonstrate the successful implementation of a PCS reflector on a high-tensile stress Si_(3)N_(4) nanomembrane.We illustrate the physical process underlying the high reflectivity by measuring the photonic-crystal band diagram.Moreover,we introduce a clear theoretical description of the membrane scattering properties in the presence of optical losses.By embedding the PCS inside a high-finesse cavity,we fully characterize its optical properties.The spectrally,angular-and polarization-resolved measurements demonstrate the wide tunability of the membrane’s reflectivity,from nearly 0 to 99.9470±0.0025%,and show that material absorption is not the main source of optical loss.Moreover,the cavity storage time demonstrated in this work exceeds the mechanical period of low-order mechanical drum modes.This so-called resolved-sideband condition is a prerequisite to achieve quantum control of the mechanical resonator with light.
