Local probing of the field emission stability of vertically aligned multiwalled carbon nanotubes

Metallic cantilever in high vacuum atomic force microscope has been used as anode for field emission experiments from densely packed vertically aligned multi-walled carbon nanotubes. The high spatial resolution provided by the scanning probe technique allowed precise setting of the tip-sample distance in the submicron region. The dimension of the probe (curvature radius below 50nm) allowed to measure current contribution from sample areas smaller than 1um^2. The study of long-term stability evidenced that on these small areas the field emission current remains stable (within 10% fluctuations) several hours (at least up to 72 hours) at current intensities between 10-5A and 10-8A. Improvement of the current stability has been observed after performing long-time Joule heating conditioning to completely remove possible adsorbates on the nanotubes.Comment: 15 pages, 7 figure

Hubungan Pengetahuan Ibu Tentang Manfaat Bermain Dengan Perkembangan Anak Usia Prasekolah Di Taman Kanak-kanak Anugerah Tumaratas Dua Kecamatan Langowan Barat

: Knowledge and mother's roles are very useful for child development thoroughly because parents could recognize the excess of child development process earlier and possibly to give stimulate to child growth including physically, mentally and social. The purpose of this study was to determine the relationship of mother's knowledge about the benefits of playing with the development of preschool childrens in Anugerah Kindergarten Tumaratas Two District of West langowan. The design of this study used cross sectional method. The population in this study were all mothers and children in the Anugerah Kindergarten Tumaratas Two District west Langowan, who have met the inclusion criteria. The sampling technique used is Saturated Samples. Instrument used was a questionnaire. The conclusion is that knowledge of mothers about the benefits of playing with the child's development have gained value (p =0.004<α 0.05). Good knowledge of parents about the benefits of play for childrens can affect the development of children so that children achieve optimal development of the appropriate age. Advice through research that the mothers can apply the benefits of play to childrens in accordance with the age of the child

Electromechanical properties of suspended Graphene Nanoribbons

Graphene nanoribbons present diverse electronic properties ranging from semiconducting to half-metallic, depending on their geometry, dimensions and chemical composition. Here we present a route to control these properties via externally applied mechanical deformations. Using state-of-the-art density functional theory calculations combined with classical elasticity theory considerations, we find a remarkable Young's modulus value of ~7 TPa for ultra-narrow graphene strips and a pronounced electromechanical response towards bending and torsional deformations. Given the current advances in the synthesis of nanoscale graphene derivatives, our predictions can be experimentally verified opening the way to the design and fabrication of miniature electromechanical sensors and devices based on ultra-narrow graphene nanoribbons.Comment: 12 pages, 6 figure

High-energy D/sub 2/O submillimeter laser for plasma diagnostics

A narrow line optically pumped D/sub 2/O laser operating at 385 ..mu..m has delivered more than 5 J in pulses longer than 3 ..mu..sec using a large aperture unstable resonator cavity design. Pulse levels which are > 1 J and 1 ..mu..sec are necessary for a single shot ion temperature measurement by Thomson scattering in large tokamaks. Experiments have, for the most part, been conducted at a 360 J, 5 ..mu..sec CO/sub 2/ laser pump level where high efficiency (approx. 2.5 J at 385 ..mu..m) has been obtained. These are the highest energies reported to date in the far infrared. In addition, the pulse length has been extended beyond the vibrational relaxation time

Cannibalism of olivine-rich cumulate xenoliths during the 1998 eruption of Piton de la Fournaise (La Réunion hotspot): Implications for the generation of magma diversity

International audienc

Préparations de Phenoxyalkylamines Substituées

Several new phenoxyalkylamines (8 to 17) were obtained either by reductive ammonolysis of phenoxyalkanones (2), by reduction of phenoxycyanoalkanes (4), by reduction of oximes (3) or by the application of the Gabriel reaction of phenoxyhalogenoethanes (5), depending upon the nature of the aliphatic chain or upon the substituents on the aromatic ring. Copyright © 1976 Wiley‐VCH Verlag GmbH & Co. KGaA, WeinheimSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Population inversion and gain measurements for soft x-ray-laser development in a magnetically confined plasma column

We present population inversion and gain measurements from an experimental investigation of possibilities to obtain high gain and lasing action in the soft x-ray region. Our approach to soft x-ray-laser development is based on rapid plasma cooling after the laser pulse by radiation losses, leading to fast recombination and collisional cascade into upper excited levels of CVI, for example, while the lower excited levels depopulate rapidly by radiative transitions, thus creating population inversions and gain. A approx. = 0.5 kJ CO/sub 2/ laser was focused onto a target of solid carbon or teflon; or CO/sub 2/, O/sub 2/, Ne gas, and the resulting plasma confined in a 50 to 90 kG magnetic field. Spectroscopic diagnostics with absolute intensity calibration were used to measure level populations

Integration of Social Concerns in Collaborative Logistics and Transportation Networks

Part 21: Mobility and LogisticsInternational audienceFreight transport optimization, long based solely on an economic approach, happen today through the integration of environmental and/or social concerns, in line with the objectives of sustainable development. In the case of Small and Very Small Enterprises, these objectives cannot be reached individually, and these companies have to join their efforts to find collective solutions. Therefore, the Fleet Size and Mix Vehicle Routing Problem (FSMVRP) was adapted to take into account social objectives, and results are compared to Vehicle Routing Problem with homogeneous fleet. An exact mathematical formulation of the extended problem was developed. Computational experiments for the problem formulation are performed using CPLEX and give a solution of a small instance to illustrate the problem. The model is tested on a case study of optimal parcel pickup, from many manufacturers to a common depot in the agri-food sector