939 research outputs found
Large suppression of quantum fluctuations of light from a single emitter by an optical nanostructure
We investigate the reduction of the electromagnetic field fluctuations in
resonance fluorescence from a single emitter coupled to an optical
nanostructure. We find that such hybrid system can lead to the creation of
squeezed states of light, with quantum fluctuations significantly below the
shot noise level. Moreover, the physical conditions for achieving squeezing are
strongly relaxed with respect to an emitter in free space. A high degree of
control over squeezed light is feasible both in the far and near fields,
opening the pathway to its manipulation and applications on the nanoscale with
state-of-the-art setups.Comment: 10 pages, 5 figure
LDEF fiber-composite materials characterization
Degradation of a number of fiber/polymer composites located on the leading and trailing surfaces of LDEF where the atomic oxygen (AO) fluences ranged from 10(exp 22) to 10(exp 4) atoms/cm(sup 2), respectively, was observed and compared. While matrices of the composites on the leading edge generally exhibited considerable degradation and erosion-induced fragmentation, this 'asking' process was confined to the near surface regions because these degraded structures acted as a 'protective blanket' for deeper-lying regions. This finding leads to the conclusion that simple surface coatings can significantly retard AO and other combinations of degrading phenomena in low-Earth orbit. Micrometeoroid and debris particle impacts were not a prominent feature on the fiber composites studied and apparently do not contribute in a significant way to their degradation or alteration in low-Earth orbit
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Nanotailoring Stereolithography Resins for Unique Applications using Carbon Nanotubes
Nanostructured materials and exploiting their properties in stereolithography (SL) may open
new markets for unique rapidly manufactured functional devices. Controlled amounts of multiwalled carbon nanotubes (MWCNTs) were successfully dispersed in SL epoxy-based resins and
complex three-dimensional (3D) parts were successfully fabricated by means of a multi-material
SL setup. The effect of the nanosized filler was evaluated using mechanical testing. Small
dispersions of MWCNTs resulted in significant effects on the physical properties of the
polymerized resin. A MWCNT concentration of .05 wt% (w/v) in DSM Somos® WaterShed™
11120 resin increased the ultimate tensile stress and fracture stress an average of 17% and 37%,
respectively. Electron microscopy was used to examine the morphology of the nanocomposite
and results showed affinity between the MWCNTs and SL resin and identified buckled
nanotubes that illustrated strong interfacial bonding. These improved physical properties may
provide opportunities for using nanocomposite SL resins in end-use applications. Varying types
and concentrations of nanomaterials can be used to tailor existing SL resins for particular
applications.Mechanical Engineerin
Trapping and observing single atoms in the dark
A single atom strongly coupled to a cavity mode is stored by
three-dimensional confinement in blue-detuned cavity modes of different
longitudinal and transverse order. The vanishing light intensity at the trap
center reduces the light shift of all atomic energy levels. This is exploited
to detect a single atom by means of a dispersive measurement with 95%
confidence in 0.010 ms, limited by the photon-detection efficiency. As the atom
switches resonant cavity transmission into cavity reflection, the atom can be
detected while scattering about one photon
Effectof osmotic dehydration in sucrose solution in the drying kinetics of cashew apple (Anacardium occidentale L.).
The Ănfluence of osmotĂc dehydratĂon Ăn sucrose solution (52% w/w) for 165 minutes in the dryĂng kĂnetĂcs of cashew apple was studied. Drying tests were conducted usĂng a fixed bed dryer at three dĂfferent temperatures (50, 60 and 70°C) and aĂr velocĂty of 2.1 m/s. Results showed that an Ăncrease of the aĂr temperature favoured the decrease of the dryĂng time of the product. The water effectĂve diffusion coefficients were determined accordĂng to Fick's second law applied to a thĂn slab and were found to be Ăn the order of 10-10 m2/s. The effectĂve diffusion coefficient decreased for the osmosed cashew apple, ĂndĂcatĂng a less favoured dĂffusĂonal processo However, the pretreated samples were characterĂzed by a flexĂble structure, by a smaller shrinkage and by presentĂng a more natural coloratĂon. The activatĂon energy,calculated usĂng Arrhenius equation, was found to be 36.45 kJ/mol for fresh fruit and 26.63 kJ/mol for the osmosed sample
Evidence of Low-Temperature Superparamagnetism in Mn_{4}$ Nanoparticle Ensembles
Please refer to the abstract within the main body of the paper
Triple domestic heat recovery system: thermal modeling and parametric study
International audienc
Vacuum-stimulated cooling of single atoms in three dimensions
Taming quantum dynamical processes is the key to novel applications of
quantum physics, e.g. in quantum information science. The control of
light-matter interactions at the single-atom and single-photon level can be
achieved in cavity quantum electrodynamics, in particular in the regime of
strong coupling where atom and cavity form a single entity. In the optical
domain, this requires permanent trapping and cooling of an atom in a
micro-cavity. We have now realized three-dimensional cavity cooling and
trapping for an orthogonal arrangement of cooling laser, trap laser and cavity
vacuum. This leads to average single-atom trapping times exceeding 15 seconds,
unprecedented for a strongly coupled atom under permanent observation.Comment: 4 pages, 4 figure
Domestic thermoelectric cogeneration drying system: Thermal modeling and case study
The demand for reducing fuel consumption and mitigating exhaust fumes accountable for the greenhouse effect push toward developing efficient energy recovery systems. Optimizing the heat recovery process can be achieved by adding multi-recovery stages. In this frame, the present work suggests a new multi-stage recovery system for heating water and air and generating electricity. The concept of the system is applied to the exhaust gases of a chimney. A complete thermal modeling of the system is drawn. Then a case study is carried out for three different fed fuels (diesel, coal, wood). The results show that when diesel is used water temperature achieved 351 K and 240 W electric power is generated. Moreover, a 0.16 m2 heat recovery heat exchanger area is required to heat air to 363 K at an air flow rate of 0.0076 kg/s. Such system can recover up to 84% of the energy lost to the environment when wood is utilized as a fed fuel
Changes in Activities of Antioxidant Enzymes and Their Relationship to Genetic and Paclobutrazol-Induced Chilling Tolerance of Maize Seedlings
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