6,100 research outputs found
Funding the Future: Resources for Adolescent Reproductive and Sexual Health Programs in Developing Countries
Provides a directory of over 90 foundations, agencies, and organizations that support adolescent reproductive and sexual health related programs in developing countries, through direct and/or indirect financing, technical assistance, and information
ENVIRONMENTAL AND ECONOMIC IMPACTS OF AGRICULTURAL POLICY REFORM: AN INTERREGIONAL COMPARISON
Mathematical programming results revealed that moving toward more flexible agricultural policies would generate substantial economic and environmental gains in a North Carolina diversified cropping region. But in a Washington-Idaho dryland grains region, only the use of relatively new and sometimes problematic alternative cropping systems permitted environmental and economic gains under policy reform. In both regions, a recoupling policy, which links government payments to resource-conserving farming practices, was needed to protect environmental quality when market prices for program crops were high.Agrichemical leaching, Agricultural policy, Alternative agriculture, Erosion, Mathematical programming, Agricultural and Food Policy,
Operational experiences and characteristics of the M2-F2 lifting body flight control system
M2-F2 lifting body flight control syste
Mechanical On-Chip Microwave Circulator
Nonreciprocal circuit elements form an integral part of modern measurement
and communication systems. Mathematically they require breaking of
time-reversal symmetry, typically achieved using magnetic materials and more
recently using the quantum Hall effect, parametric permittivity modulation or
Josephson nonlinearities. Here, we demonstrate an on-chip magnetic-free
circulator based on reservoir engineered optomechanical interactions.
Directional circulation is achieved with controlled phase-sensitive
interference of six distinct electro-mechanical signal conversion paths. The
presented circulator is compact, its silicon-on-insulator platform is
compatible with both superconducting qubits and silicon photonics, and its
noise performance is close to the quantum limit. With a high dynamic range, a
tunable bandwidth of up to 30 MHz and an in-situ reconfigurability as beam
splitter or wavelength converter, it could pave the way for superconducting
qubit processors with integrated and multiplexed on-chip signal processing and
readout.Comment: References have been update
Experimental demonstration of evanescent coupling from optical fibre tapers to photonic crystal waveguides
Experimental results demonstrating nearly complete mode-selective evanescent coupling to a photonic crystal waveguide from an optical fibre taper are presented. Codirectional coupling with 98% maximum power transfer to a photonic crystal waveguide of length 65 ÎĽm and with a coupling bandwidth of 20 nm is realised
Surface Encapsulation for Low-Loss Silicon Photonics
Encapsulation layers are explored for passivating the surfaces of silicon to
reduce optical absorption in the 1500-nm wavelength band. Surface-sensitive
test structures consisting of microdisk resonators are fabricated for this
purpose. Based on previous work in silicon photovoltaics, coatings of SiNx and
SiO2 are applied under varying deposition and annealing conditions. A short dry
thermal oxidation followed by a long high-temperature N2 anneal is found to be
most effective at long-term encapsulation and reduction of interface
absorption. Minimization of the optical loss is attributed to simultaneous
reduction in sub-bandgap silicon surface states and hydrogen in the capping
material.Comment: 4 pages, 3 figure
Design of photonic crystal microcavities for cavity QED
We discuss the optimization of optical microcavity designs based on 2D
photonic crystals for the purpose of strong coupling between the cavity field
and a single neutral atom trapped within a hole. We present numerical
predictions for the quality factors and mode volumes of localized defect modes
as a function of geometric parameters, and discuss some experimental challenges
related to the coupling of a defect cavity to gas-phase atoms.Comment: 12 pages, 16 figure
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