We study hole transport behavior of InGaN/GaN light-emitting diodes with the dual wavelength emission method. It is found that at low injection levels, light emission is mainly from quantum wells near p-GaN, indicating that hole transport depth is limited in the active region. Emission from deeper wells only occurs under high current injection. However, with Mg-doped quantum barriers, holes pen...

The paper describes the theoretical framework and results of using an rapid three-dimensional super element model of oil field development. The model makes it possible to speed up calculation of two-phase filtration in an oil reservoir by hundreds of times owing to the use of large computational cells – super elements, the number of which corresponds to the number of wells in the field. Accurac...

A silicon nanosensor technology based on electrical impedance measurements has been developed for the detection of proteins. The nanosensor miniaturizes the high-density, low-volume multiwell plate concept. The scientific core of this technology lies in integrating nanoporous membranes with microfabricated chip platforms. This results in the conversion of individual pores into nanowells of pico...

For two dimensional Schrr odinger operators with a nonzero constant magnetic eld perturbed by an innnite number of periodically disposed, long range magnetic and electric wells, it is proven that when the inter-well distance (R) grows to innnity, the essential spectrum near the eigenvalues of the \one well Hamiltonian" is located in mini-bands whose width shrink faster than any exponential with...

Positrons, which scatter back from the target and annihilate in chamber walls near the detectors, may cause a significant error in annihilation parameters. We have constructed a new UHV target chamber for slow positron beam studies. In our design special care has been taken to reduce the effect of backscattered positrons. Detector wells are designed for two-detector coincidence measurements and...

Reservoir simulators remain essential tools for improved reservoir management in order to optimize hydraulic fracturing design in unconventional low permeability reservoirs. However, the commonly-used simulator requires too much computational efforts for the description of local phenomena in the vicinity of the hydraulic fractures, and is practically infeasible for field applications, due to la...

This study was conducted over seven villages near Darbandikhan district including (2) wells and (5) springs. It covers more than 60 km, to assess the suitability of ground water quality for drinking purpose using water quality index through investigating of different wells and springs; this technique is very useful tool for quick assessment for any water system. This was done by subjecting the ...

Arsenic in groundwater has been a concern in South and Southeast Asia for more than a decade. We explore here the possibility that hydrogeologic factors recently shown to influence the distribution of arsenic might also affect the level of contamination of shallow (<20 m) wells with microbial pathogens. A total of 96 shallow tube wells in two nearby villages of Bangladesh were surveyed during t...