Subjects observed a random dot pattern that moved horizontally with modulated velocity within an invisible aperture. The velocity contrast, (V2-V1)/V1, was 2/3. Two different percepts occurred while observing this stimulus. At lower modulation frequencies, between 2 and 12 Hz, velocity changes were clearly seen; this percept is called "motion irregularity". At frequencies higher than 20 Hz velo...

Treatment of small animals with radiation has in general been limited to planar fields shaped with lead blocks, complicating spatial localization of dose and treatment of deep-seated targets. In order to advance laboratory radiotherapy toward what is accomplished in the clinic, we have constructed a variable aperture collimator for use in shaping the beam of microCT scanner. This unit can image...

more than half of all hydrocarbon reservoirs are naturally fractured reservoirs (nfrs), in which production forecasting is a complicated function of fluid flow in a fracture-matrix system. modelling of fluid flow in nfrs is challenging due to formation heterogeneity and anisotropy. stress sensitivity and depletion effect on already-complex reservoir permeability add to the sophistication. horiz...

Light usually diffracts in all directions when it emerges from a subwavelength aperture, which puts a lower limit on the size of features that can be used in photonics. This limitation can be overcome by creating a periodic texture on the exit side of a single aperture in a metal film. The transmitted light emerges from the aperture as a beam with a small angular divergence (approximately +/-3 ...

The scaling limits of multi-aperture systems have been widely discussed from an information-theoretical standpoint. While these arguments are valid as an upper limit, the real-world performance of systems for mobile devices remains restricted by optical aberrations. We argue that aberrations can be more easily controlled with certain architectures of multi-aperture systems, especially those man...

This paper presents a simple and effective method to fabricate a polydimethyl-siloxane (PDMS) microlens array with a high fill factor, which utilizes the UV proximity printing and photoresist replication methods. The concave microlens array mold was made using a printing gap in lithography process, which utilizes optical diffraction of UV light to deflect away from the aperture edges and produc...

Water deficit strongly affects crop productivity. Plants control water loss and CO2 uptake by regulating the aperture of the stomatal pores within the leaf epidermis. Stomata aperture is regulated by the two guard cells forming the pore and changing their size in response to ion uptake and release. While our knowledge about potassium and chloride fluxes across the plasma membrane of guard cells...

A near-field optical virtual probe (NFOVP) is a type of immaterial tip based on the principle of near-field evanescent wave interference. Evanescent wave interference and the aperture type play very significant roles in generating near-field optical virtual probes. Two evanescent waves, propagating in opposite directions, will interfere to generate the confinement field. The central peak of the...

We report on the numerical analysis of the electrical and optical properties of current-injected III-nitride based vertical-cavity surface-emitting lasers (VCSELs) with three types of current confinement schemes: the conventional planar-indium tin oxide (ITO) type, the AlN-buried type without ITO, and the hybrid type. The proposed hybrid structure, which combines an ITO layer and an intracavity...

We report on the theoretical analysis of a novel type of vertical-cavity surface-emitting laser (VCSEL) that provides selection of a certain higher-order transverse mode. This selection is based on a spatial variation of the threshold gain by adding an antiphase layer with an etched relief structure. The field intensity profile emitted from this laser is calculated numerically as well as with a...