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Consequence of shape elongation on emission asymmetry for colloidal CdSe/CdS nanoplatelets

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Nano Research 2018年第7期11卷 3593-3602页

作者： Fu Fengt Loan Thu Nguyen Michel Nasilowski Brice Nadal Benoit Dubertret Laurent Coolent Agnes Maitre Sorbonne Universites UPMC Univ Paris 06 CNRS-UMR 7588 Institut des NanoSciences de Paris F-75005 Paris France Institute of Materials Science Vietnam Academy of Science and Technology 18 Hoang Quoc Viet Road Cau Giay Dist. 100000 Hanoi Vietnam laboratoire de Physique et d'Etude des materiaux ESPCI UPMC Univ Paris 6 CNRS 10 rue Vauquelin F-75005 Paris France

In this paper, we demonstrate that for colloidal CdSe/CdS nanoplatelets, a rectangular shape induces emission asymmetry, in terms of both polarization and emission patterns. Polarimetry and emission pattern analyses are combined to provide information on the orientation of the transition dipoles involved in the nanoplatelet emission. It is shown that for rectangular nanoplatelets, the emission is polarized and the emission patterns are anisotropic, whereas they remain nonpolarized and isotropic for square nanoplatelets. This can be appropriately described by the dielectric antenna effect induced by the elongated shape of the rectangular platelet.

关键词： colloidal semiconductor nanoplatelet emission dipole emission polarization emission pattern

Growth of high-quality thick GaN using a tungsten interlayer

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Rare Metals 2006年第Z2期25卷 11-14页

作者： NOUET Gérard RUTERANA Pierre laboratoire Structures des Interfaces et Fonctionnalité des Couches Minces UMR CNRS 6176 ENSICAEN 6 Boulevard du Maréchal Juin 14050 Caen Cedex France

A high-quality GaN film was (W-GaN) grown by hydride vapor phase epitaxy (HVPE) on metalorganic chemical vapor deposition (MOCVD) GaN templates with a tungsten (W) interlayer. A sample without interlayer was also grown at the same time for comparison. Significant reductions of dislocation density in W-GaN film is confirmed by the result of high-resolution X-ray diffraction and transmission electron microscope (TEM) observation. The improvement of optical properties of the W-GaN is confirmed by photoluminescence (PL) result. A shift of PL peak suggests that the strain is lower in the W-GaN than the film without W interlayer. This technique offers a potential path to obtain high-quality GaN film as free-standing substrate.

关键词： GaN tungsten interlayer HVPE HRXRD

Direct Ni Electroless Metallization of Poly(etherimide) without Using Palladium as a Catalyst

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材料热处理学报 2004年第05B期25卷 1106-1111页

作者： Marlène Charbonnier Maurice Romand Yves Goepfert laboratoire de Sciences et Ingenierie des Surfaces Universite Claude Bernard - Lyon 1 69622 Villeurbanne Cedex FranceLaboratoire de Sciences et Ingenierie des Surfaces Universite Claude Bernard - Lyon 1 69622 Villeurbanne Cedex FranceUMR 5180 des Sciences Analytiques Universite Claude Bernard - Lyon 1 69622 Villeurbanne Cedex France

Nickel or copper electroless metallization of polymers needs the grafting of a catalyst (palladium in the Pd(0) oxidation state) on the substrate surface to be coated. Our previous works on this topic [1-5] have allowed to develop a simple, tin-free method to attach Pd(+2) species from a palladium chloride (PdCl2) solution on any insulating surface and subsequently to reduce them, in the wet way, into the Pd(0) oxidation state. This Pd(0) state of the catalyst allows an instantaneous initiation of the Ni or Cu deposit by immersion in a plating bath. As palladium is an expensive chemical, it appears interesting to replace it by Ni(0) or Cu(0) species which are catalysts of their own ion reduction. Concerning the direct Ni electroless plating, the polymer surface (PI) was made catalytic for the electroless process by deposition (spin- coating or dipping) of an ultra-thin film of an organic nickel salt in an alcoholic solution. The chemical reduction of this salt, checked by XPS, was performed by chemical or photochemical ways and by plasma. Under these conditions, the initiation, by autocatalysis, of the Ni film deposition in an industrial plating bath was immediate i.e. without any initiation time. The film obtained was homogeneous, dense, bright, well-adhering up to thicknesses reaching

关键词：镍非电金属喷镀等离子处理 XPS 聚酰亚胺

Effect of AlN intermediate layer on growing GaN film by hydride vapor phase epitaxy

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Rare Metals 2006年第Z2期25卷 15-19页

作者： NOUET Gérard2 RUTERANA Pierre laboratoire Structures des Interfaces et Fonctionnalité des Couches Minces UMR CNRS 6176 ENSICAEN6 Boulevard du Maréchal Juin 14050 Caen Cedex France

Thick GaN layer deposited by hydride vapor phase epitaxy (HVPE) on a metalorganic chemical vapor deposition (MOCVD) GaN template with a thin low temperature (LT) AlN intermediate layer was investigated. High resolution X-ray resolution diffraction (HRXRD) shows that the crystalline quality of thick GaN layer was improved compared with the template. As confirmed by atomic force microscopy (AFM) observations, the surface morphology of AlN intermediate layer helps to improve the nucleation of GaN epilayer. Photoluminescence (PL) spectra measurement shows its high optical quality and low compressive stress, and micro Raman measurement confirms the latter result. Thus, the deposition of the LT-AlN interlayer has promoted the growth of an HVPE-GaN layer with an excellent crystalline quality.

关键词： GaN AlN intermediate layer HVPE HRXRD AFM photoluminescence

Decoherence Effect and Beam Splitters for Production of Quasi-Amplified Entangled Quantum Optical Light

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Communications in Theoretical Physics 2018年第3期69卷 311-316页

作者： Saad Rfifi laboratoire des Sciences et Technologies Avances Facult Polydisciplinaire de LaracheUniversit Abdelmalek ESSAADI

We let a set of beam splitters of vacuum mode with a chosen transmittance parameter η in interaction with a separable coherent *** model induces the production of an attenuated quantum channels based on entangled optical ***,the decoherence effect is exploited positively here to generate such kind of quantum ***,the amplitude damping and the entanglement amount of these produced channels are enhanced thereafter by a probabilistic quasi amplification process using again a 50 : 50 beam splitter.

关键词： beam splitters production quasi probabilistic amplification quantum channels decoherence effect entangled optical states entanglement amount

A REMARK ON THE HAUSDORFF DIMENSION OF CERTAIN NON-SELF-SIMILAR ATTRACTORS

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Chinese Annals of Mathematics,Series B 1997年第1期18卷 119-124页

作者： LIU HONGGEN laboratoire des Fluides Automatique et Systemes TbermiquesBgtiment 502Campus universitaire91405 OrsayFrance

Ellis and Branton introduced a class of non-self-similar sete;they gave an upper bound of Hausdorff dimension for such sets,and a conjecture of the lower bound for these *** paper gives a proof of this conjecture by u... 详细信息

关键词： Non-self-similar attractor Hausdorff dimension Ellis and Branton conjecture Iterated function system

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Vetiver Grass and Micropollutant Leaching Through Structured Soil Columns Under Outdoor Conditions

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Pedosphere 2016年第4期26卷 522-532页

作者： Sylvie DOUSSET Norbert ONDO ZUE ABAGA David BILLET Universite de Lorraine-CNRS-laboratoire Interdisciplinaire des Environnements Continentaux (LIEC) 56506 Vandoceuvre-les-Nancy

In Burkina Faso, significant amounts of endosulfan are applied to cotton fields; in addition, urban vegetable agriculture is often characterised by high fertiliser inputs, such as urban solid wastes containing heavy metals(e.g., Cu and Cd). Thus, the relevance of surrounding cotton and urban vegetable plots with vetiver(Vetiveria zizanioides) hedges to reduce environmental pollution by micropollutants was investigated using a leaching experiment, with outdoor lysimeters filled with two representative agricultural soils of Burkina Faso: Vertisol and Lixisol. After 6 months, little Cu was found in the leachates(despite leachate and bromide recoveries being greater in soils planted with vetiver grass than in the bare soils, smaller amounts of endosulfan and Cd were found in the effluents from the planted soils(0.01% to 0.70% of the applied amount) than in those from the bare soils(0.01% to 1.48% of the applied amount), in agreement with their adsorption coefficients. These results may also be explained by a greater degradation of endosulfan in planted soils compared to bare soils and the absorption of Cd by vetiver. Thus, vetiver may decrease the risk of groundwater contamination,especially for Cd and endosulfan, which are more mobile than Cu. In addition, despite the smaller amounts of endosulfan and Cd measured in the Vertisol leachates(0.01% and 0.04% of the applied amount, respectively) compared to the Lixisol leachates, vetiver was more effective in decreasing the leaching of micropollutants if planted on Lixisol rather than on Vertisol. Further field monitoring is necessary to demonstrate the effectiveness of vetiver under the climatic conditions of Burkina Faso.

关键词： cadmium copper endosulfan Lixisol lysimeter transfer Vertisol

Synthesis and characterization of poly(2,5-diyl pyrrole-2-pyrrolyl methine)semiconductor copolymer

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Journal of Semiconductors 2018年第10期39卷 10-16页

作者： Hammou Gherras Ahmed Yahiaoui Aicha Hachemaoui Abdelkader Belfedal Abdelkader Dehbi Abdel-Hamid I.Mourad laboratoire de chimie Organique Macromoleculaire et des Materiaux(LCOMM)Universite de MascaraFaculte des Sciences ExactesBP 763 Mascara 29000Algeria laboratoire de Chimie Physique des Macromolecules et Interfaces Biologiques Universite de Mascara Algeria laboratoire de Genie Physique Universite d'Ibn KhaldounTiaret BP 78 14000 TiaretAlgeria Mechanical Engineering Department College of EngineeringUnited Arab Emirates UniversityAl-AinUAE On leave from Mechanical design Department Faculty of EngineeringHelwan UniversityCairoEgypt

The proposed technique to synthesise poly {（2,5-diyl pyrrole）（2-pyrrolyl methine）}（PPPM） copolymer by condensation of pyrrole and pyrrole-2-carboxaldehyde monomers catalyzed by Maghnite-H＋ is *** protons are exchanged with Maghnite-H＋, which is available in the form of a montmorillonite silicate clay sheet. The effect of several parameters such as time and temperature of copolymerization, [pyrrole]/[pyrrole-2-carboxaldehyde] molar ratio, amount of Maghnite-H＋, and solvent on the produced poly（2,5-diyl pyrrole-2-pyrrolyl methine） semiconductor copolymer material（yield%） was investigated. The synthesized PPPM copolymer was characterized using nuclear magnetic resonance, Fourier transform infrared, and ultraviolet-visible *** results show that the synthesized copolymer using the copolymerization technique is a real organic copolymer consisting of two monomers units（i.e, pyrrole and pyrrole-2-carboxaldehyde）. Also, the synthesized copolymer is more soluble than polypyrrole in most of the commonly used organic solvents. Hence, copolymerization of pyrrole with pyrrole-2-carboxaldehyde will overcome the insolubility of polypyrrole. In addition, the resultant copolymer exhibits good film formability. The produced copolymer has several potential applications in the field of rechargeable batteries, sensors, capacitors, light emitting diodes, optical displays, and solar cells.

关键词： proposed technique Maghnite-H^+ catalyst conducting PPPM copolymer pyrrole pyrrole-2-carboxaldehyde

Degradation of direct azo dye by Cucurbita pepo free and immobilized peroxidase

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Journal of Environmental Sciences 2013年第6期25卷 1235-1244页

作者： Nabila Boucherit Mahmoud Abouseoud Lydia Adour Université Mouloud Mammeri laboratoire de Biomatériaux et de Phénomènes deTransports Université Dr.Yahia Fares laboratoire de Biomatériaux et de Phénomènes de Transports Université Dr.Yahia Fares laboratoire de Génie de la Réaction Faculté de Génie Mécanique et Génie des ProcédésUniversité Houari Boumediene laboratoire des Biotechnologies Environnementales et Génie des Procédés

Enzymatic decolourization of the azo dye, Direct Yellow （DY 106） by Cucurbita pepo （courgette） peroxidase （CP） is a complex process, which is greatly affected by pH, temperature, enzyme activity and the concentrations of H202 and dye. Courgette peroxidase was extracted and its performance was evaluated by using the free-CP （FCP） and immobilized-CP （ICP） forms in the decolourization of DY106. Immobilization of peroxidase in calcium alginate beads was performed according to a strategy aiming to minimize enzyme leakage and keep its activity at a maximum value by optimizing sodium alginate content, enzyme loading and calcium chloride concentration. The initial conditions ~it which the highest DY106 decolourization yield was obtained were found at pH 2, temperature 20~C, H202 dose 1 mmol/L （FCP） and 100 mmol/L （ICP）. The highest decolourization rates were obtained for dye concentrations 50 mg/L （FCP） and 80 mg/L （ICP）. Under optimal conditions, the FCP was able to decolorize more than 87% of the dye within 2 min. While with ICP, the decolourization yield was 75% within 15 rain. The decolourization and removal of DY106 was proved by UV-Vis analysis. Fourier transform infrared （FF-IR） spectroscopy analysis was also performed on DY106 and enzymatic treatment precipitated byproduct.

关键词： Cucurbita pepo peroxidase immobilization decolourization azo dye