Diversité des espèces de mouches des fruits (Diptera : Tephritidae) dans un verger mixte dans la localité de Malang (Ngaoundéré, Cameroun)

La présente étude avait pour but d’inventorier les espèces de mouches des fruits (Diptera :Tephritidae) inféodées au manguier dans la localité de Malang, située dans la région de l’Adamaoua (Ngaoundéré, Cameroun), en zone Soudano-Guinéenne. Pour cela, nous avons identifié les principales espèces présentes dans le verger grâce à un piégeage de détection d’avril 2008 à avril 2009, et, d’autre part, nous avons cherché à connaître les espèces responsables des dégâts à partir du ramassage des mangues dans le verger. Au total, 83 052 adultes de mouches des fruits appartenant à neuf espèces ont été capturés et huit espèces ont été déterminées. L’espèce invasive Bactrocera invadens Drew Tsuruta & White est la plus abondante dans les pièges (66,55% des captures), suivie de Dacus punctatifrons (Karsch) (29,92% des captures). La troisième espèce par ordre d’importance est Ceratitis cosyra (Walker) (3,38% des captures).Six autres espèces sont présentes mais en très faible effectif (avec au total 0,15% des captures). Les adultes de Tephritidae qui ont émergé des mangues mûres ramassées sous les arbres appartiennent à deux espècesB. invadens (98,5%) et D. punctatifrons (1,5%). Le pic de pullulation de B. invadens coïncide avec celui des mangues arrivées à maturité alors que D. punctatifrons est surtout présent après la période de maturitédes mangues. B. invadens est la principale espèce de Tephritidae responsable des dégâts sur mangues à Malang. Les organisations de protection phytosanitaire doivent mettre en oeuvre dans les meilleurs délais des programmes de lutte intégrée afin de pouvoir réduire les dégâts de cette nouvelle espèce invasive en dessous d’un seuil économique de nuisibilité

ZnO Nanorods via Spray Deposition of Solutions Containing Zinc Chloride and Thiocarbamide

In this work we present the results on formation of ZnO nanorods prepared by spray of aqueous solutions containing ZnCl2and thiocarbamide (tu) at different molar ratios. It has been observed that addition of thiocarbamide into the spray solution has great impact on the size, shape and phase composition of the ZnO crystals. Obtained layers were characterized by scanning electron microscopy (SEM) equipped with energy selected backscattered electron detection system (ESB), X-ray diffraction (XRD) and photoluminescence spectroscopy (PL). Small addition of thiocarbamide into ZnCl2solution (ZnCl2:tu = 1:0.25) supports development of significantly thinner ZnO nanorods with higher aspect ratio compared to those obtained from ZnCl2solution. Diameter of ZnO rods decreases from 270 to 100 nm and aspect ratio increases from ∼2.5 to 12 spraying ZnCl2and ZnCl2:tu solutions, respectively. According to XRD, well crystallized (002) orientated pure wurtzite ZnO crystals have been formed. However, tiny ‘spot’—like formations of ZnS were detected on the side planes of hexagonal rods prepared from the thiocarbamide containing solutions. Being adsorbed on the side facets of the crystals ZnS inhibits width growth and promotes longitudinalc-axis growth

Morphology-Controllable Synthesis of CeO2on a Pt Electrode

Nanoscale cerium dioxides with shape of nanoparticles, nanorods, and nanotubes were electrochemically synthesized. The morphology of CeO2was modulated by changing electrode potential and potential direction. CeO2nanorods and CeO2nanotubes were synthesized via the potentiostatic and cyclic voltammeteric methods, respectively. The morphology and structure of the obtained CeO2were characterized by field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD). A possible formation mechanism has been suggested to illuminate the relationship between the preparation condition and the morphology of CeO2

Fabrication of vertically aligned Pd nanowire array in AAO template by electrodeposition using neutral electrolyte

A vertically aligned Pd nanowire array was successfully fabricated on an Au/Ti substrate using an anodic aluminum oxide (AAO) template by a direct voltage electrodeposition method at room temperature using diluted neutral electrolyte. The fabrication of Pd nanowires was controlled by analyzing the current–time transient during electrodeposition using potentiostat. The AAO template and the Pd nanowires were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) methods and X-Ray diffraction (XRD). It was observed that the Pd nanowire array was standing freely on an Au-coated Ti substrate after removing the AAO template in a relatively large area of about 5 cm2, approximately 50 nm in diameter and 2.5 μm in length with a high aspect ratio. The nucleation rate and the number of atoms in the critical nucleus were determined from the analysis of current transients. Pd nuclei density was calculated as 3.55 × 108 cm−2. Usage of diluted neutral electrolyte enables slower growing of Pd nanowires owing to increase in the electrodeposition potential and thus obtained Pd nanowires have higher crystallinity with lower dislocations. In fact, this high crystallinity of Pd nanowires provides them positive effect for sensor performances especially

Developing 1D nanostructure arrays for future nanophotonics

There is intense and growing interest in one-dimensional (1-D) nanostructures from the perspective of their synthesis and unique properties, especially with respect to their excellent optical response and an ability to form heterostructures. This review discusses alternative approaches to preparation and organization of such structures, and their potential properties. In particular, molecular-scale printing is highlighted as a method for creating organized pre-cursor structure for locating nanowires, as well as vapor–liquid–solid (VLS) templated growth using nano-channel alumina (NCA), and deposition of 1-D structures with glancing angle deposition (GLAD). As regards novel optical properties, we discuss as an example, finite size photonic crystal cavity structures formed from such nanostructure arrays possessing highQand small mode volume, and being ideal for developing future nanolasers