The Huygens-Fresnel diffraction integral has been formulated for incident spherical waves with use of the Kirchhoff obliquity factor and the wave front as the surface of integration instead of the aperture plane. Accurate numerical integration calculations were used to investigate very-near-field (a few aperture diameters or less) diffraction for the well-established case of a circular aperture...

In this work, we prepare and characterize multiphasic thin films containing poly(?-caprolactone), PCL, poly(butylene succinate), PBS, a poly (butylene succinate-ran-?-caprolactone) (PBS-ran-PCL) random copolyester. To that aim, were prepared by sequential dipping of silicon substrate into chloroform solutions the respective polymers. The preparation method resulted in with varying compositions ...

We have designed, constructed, and operated a 3.8-cm clear-aperture Cr:Nd:GSGG active-mirror amplifier. We believe this to be the first active mirror that uses a crystalline host and the largest-aperture Cr:Nd:GSGG amplifier yet reported. We have measured a small-signal gain of 1.6. The wave front has been measured and found to be less than three waves of defocus at repetition rates of up to 10...

J Pak Med Assoc Madam, we applaud the efforts of Jooma et al in highlighting the deficiencies in trauma care in the developing world.1 They identify the fundamental need for health-care personnel to provide a structured initial response to trauma. The 'ABCD' trauma dogma is indispensible. However, we wish to stress that technological infrastructure should co-evolve in such services if the injur...

This is the first paper to consider a mixed oligopoly in which a public Stackelberg leader competes with both domestic and foreign private firms. The welfare maximizing leader is shown to always produce less than under previous Cournot conjectures. Introducing leadership also alters previous public pricing rules resulting in prices that may be either greater than or less than marginal cost depe...

The ambiguity function (AF) provides a convenient way to model how a camera with a modified aperture responds to defocus. We use the AF to design an optimal aperture distribution, which creates a depth-variant point spread function (PSF) from a sparse set of desired intensity patterns at different focal depths. Prior knowledge of the coherence state of the light is used to constrain the optimiz...