7,556 research outputs found
Fourier Ptychography with Scheimpflug Optics for Multi-Aperture Applications
We present a new optical configuration using the Scheimpflug principle for Fourier ptychography microscopy. This configuration minimizes the aberrations present in the off-axis lenses of a multi-aperture Fourier ptychography setup. A 3D printed setup was used to demonstrate the experimental implementation
Concerted hydrogen atom exchange between three HF molecules
We have investigated the termolecular reaction involving concerted hydrogen exchange between three HF molecules, with particular emphasis on the effects of correlation at the various stationary points along the reaction. Using an extended basis, we have located the geometries of the stable hydrogen-bonded trimer, which is of C(sub 3h) symmetry, and the transition state for hydrogen exchange, which is of D(sub 3h) symmetry. The energies of the exchange reation were then evaluated at the correlated level, using a large atomic natural orbital basis and correlating all valence electrons. Several correlation treatments were used, namely, configration interaction with single and double excitations, coupled-pair functional, and coupled-cluster methods. We are thus able to measure the effect of accounting for size-extensivity. Zero-point corrections to the correlated level energetics were determined using analytic second derivative techniques at the SCF level. Our best calculations, which include the effects of connected triple excitations in the coupled-cluster procedure, indicate that the trimer is bound by 9 +/- 1 kcal/mol relative to three separate monomers, in excellent agreement with previous estimates. The barrier to concerted hydrogen exchange is 15 kcal/mol above the trimer, or only 4.7 kcal/mol above three separated monomers. Thus the barrier to hydrogen exchange between HF molecules via this termolecular process is very low
Miniature Fourier Ptychography Microscope using Raspberry Pi Camera and Hardware
We report a Fourier ptychography setup using a raspberry pi camera sensor and its lens in reversed configuration. In this work data acquisition was performed by means of a raspberry pi board which eliminates the requirement of a computer for data acquisition thus allowing a miniaturized system for remote data acquisition costing around £100
Personalized medicine : the impact on chemistry
An effective strategy for personalized medicine requires a major conceptual change in the development and application of therapeutics. In this article, we argue that further advances in this field should be made with reference to another conceptual shift, that of network pharmacology. We examine the intersection of personalized medicine and network pharmacology to identify strategies for the development of personalized therapies that are fully informed by network pharmacology concepts. This provides a framework for discussion of the impact personalized medicine will have on chemistry in terms of drug discovery, formulation and delivery, the adaptations and changes in ideology required and the contribution chemistry is already making. New ways of conceptualizing chemistry’s relationship with medicine will lead to new approaches to drug discovery and hold promise of delivering safer and more effective therapies
Video-rate 3D Particle Tracking with Extended Depth-of-field in Thick Biological Samples
We present a single-aperture 3D particle localisation and tracking technique with a vastly increased depth-of-field without compromising optical resolution and throughput. Flow measurements in a FEP capillary and a zebrafish blood vessel are demonstrated experimentally
Inflaton potential reconstruction in the braneworld scenario
We consider inflaton potential reconstruction in the context of the simplest
braneworld scenario, where both the Friedmann equation and the form of scalar
and tensor perturbations are modified at high energies. We derive the
reconstruction equations, and analyze them analytically in the high-energy
limit and numerically for the general case. As previously shown by Huey and
Lidsey, the consistency equation between scalar and tensor perturbations is
unchanged in the braneworld scenario. We show that this leads to a perfect
degeneracy in reconstruction, whereby a different viable potential can be
obtained for any value of the brane tension . Accordingly, the initial
perturbations alone cannot be used to distinguish the braneworld scenario from
the usual Einstein gravity case.Comment: 5 pages RevTeX4 file with four figures incorporated; minor addition
to discussio
Gravitino production in the warm inflationary scenario
We estimate the production of gravitinos during and after the end of a period
of warm inflation, a model in which radiation is produced continuously as the
field rolls down the potential producing dissipation. We find that gravitino
production is efficient for models in the strong dissipation regime, with the
result that standard nucleosynthesis is disrupted unless the magnitude of the
inflaton potential is very small. Combining this with the constraint from the
thermal production of adiabatic density perturbations we find the dissipation
rate must be extraordinarily strong, or that the potential is very flat.Comment: 7 pages, 3 figures, submitted to Phys Rev
Technical Bulletins: NPDES Phase II Stormwater Permitting
In December 1999, the new National Pollutant Discharge Elimination System (NPDES) Phase II regulations were published. These regulations, which regulate stormwater discharges to U.S. waters, are mandated by the Environmental Protection Agency (EPA) and implemented in the state by the Tennessee Department of Environment and Conservation (TDEC)
- …