PURPOSE This study evaluates not only the clinical usefulness but also the problems in attenuation correction for thallium-201 (Tl-201) myocardial SPECT by means of simultaneous transmission and emission data acquisition in the detection of coronary artery disease (CAD). METHODS A three-detector SPECT system equipped with a Tc-99m line source and fan-beam collimators was used for simultaneous...

Recent advances in aberration-corrected scanning transmission electron microscopy (AC-STEM) have shown the world previously unattainable views into the atomic structure and composition of materials. Thanks to improved optics, experimental and environmental factors often limit the quality of information accessed by AC-STEM. However, collecting and processing AC-STEM data using new techniques fro...

Over a century ago George Westinghouse, with the support of Nikola Tesla, defeated Thomas Edison in the ‘War of Currents’, thereby successfully establishing alternating current (AC) as the primary mode of electricity transmission and distribution. Large power plants such as coal, nuclear and hydro, are often located far from consumption centres. With transformers, the voltage level of AC power ...

Long distance AC transmission is often subject to stability problems , which limits the transmission capability.Large interconnected power systems often suffer from weakly damped swings between synchronous generators and subsystems.This paper presents two methods , based on the use of nonlinear system model , to improve transient stability and damping of power swings using UPFC. A statevariable...

There is a great resolution calling for smart grids in recent years. Introduction of new technologies, that make the network flexible and controllable, is a main part of smart grid concept and a key factor to its success. Transmission network as a part of system network has drawn less attention. Transmission switching as a transmission service can release us from load shedding and remove the co...

The offshore wind power has received immense attention because of higher wind speed and lower opposition for construction. A wide range of combinations of high-voltage ACDC transmission have been proposed for integrating offshore wind farms and long-distance power transmission. This paper is to model such hybrid AC-DC systems including the interfacing converters, which have several control para...

Conventionally Grid Connected Solar PV plants initially generates DC power and then converted to AC via inverters and connected into AC grid for power transmission. Depending on the size of the plant, required environmental condition and land availability large PV plants are generally located far away from the load centre. Hence reduction of transmission loss and incised transmission capacity e...

We investigate the possibility to manipulate for the transport through heterostructures the dc current and its noise properties by an ac gate voltage. For a computation of the noise strength, we map the system to a tight-binding model for which noise suppression by ac fields has been predicted recently. The quality of this description is tested by comparing the transmission of the tight-binding...

Transient stability plays key role for the loading of Extra High Voltage AC lines under their thermal limits. It is not possible to load these EHV lines near the thermal limits. But, with the proposed scheme in this paper, it is possible to load these lines very close to their thermal limits. Master current controller senses ac current and regulates the dc current orders for converters online s...

We report on the focusing and guiding of the van der Waals complex formed between benzonitrile molecules (C(6)H(5)CN) and argon atoms in a cold molecular beam using an ac electric quadrupole guide. The distribution of quantum states in the guided beam is non-thermal, because the transmission efficiency depends on the state-dependent effective dipole moment in the applied electric fields. At a s...