Ga(1-x)In(x)N(y)As(1-y) is a promising material system for the fabrication of inexpensive "last-mile" optoelectronic components. However, details its atomic arrangement and relationship to observed optical properties not fully known. Particularly, blueshift emission wavelength after annealing. In this work, we use x-ray absorption fine structure study chemical environment around N atoms in before We find that as-grown molecular beam epitaxy consists nearly random distribution atoms, while...

Calculations of radiation dose are important in assessing the medical and biological implications ionizing imaging techniques such as SPECT PET. In contrast, estimates PET small animals not very well established. For that reason we have estimated whole‐body to mice rats for isotopes used commonly animal imaging. We approximated mouse rat bodies with uniform soft tissue equivalent ellipsoids. The sized ellipsoids had a mass 30 g 300 g, respectively, ratio principal axes 1:1:4 0.7:1:4....

Single photon emission computed tomography (SPECT) is an important technology for molecular imaging studies of small animals. In this arena, there increasing demand high performance systems that offer improved spatial resolution and detection efficiency. We have designed a multipinhole animal system based on position sensitive avalanche photodiode (PSAPD) detectors with the goal submillimeter efficiency, which will allow us to minimize radiation dose shorten time needed study. Our design use...

Computed tomographic imaging of tissue surrounding metallic implants is often limited by metal artifacts. This paper compares 3 existing artifact reduction techniques that are based on segmentation metal-affected regions in native images, followed reprojection segmented areas into original Radon space, removal trace(s), and renewed reconstruction: Detector row-wise linear interpolation, 2-dimensional combination interpolation adaptive filtering. For each method, improvements CT number...

A wide-bandwidth galvanically isolated current sensing circuit with an integrated Rogowski coil in 180 nm CMOS is presented. Exploiting the high-frequency properties of optimized on-chip coil, currents can be measured up to a bandwidth 75 MHz. The analog sensor front-end comprises two-stage integrator, which allows chopper frequency below signal bandwidth, resulting 2.2mVrms output noise. An additional Hall extends measurement range towards DC.

A wide-bandwidth galvanically isolated current sensor in a 180 nm CMOS technology is presented. It combines two sensing principles for the contactless and lossless measurement power electronic applications. dedicated vertical Hall (low frequencies) an integrated helix-shaped Rogowski coil (high enable to measure currents any line under chip from DC up 15.3 MHz, which exceeds prior art by 5x. Both concepts are fully on one microchip without need kind of magnetics or post-processing. The wide...

The 5-subunit-containing acetyl-CoA decarbonylase/synthase (ACDS) complex plays an important role in methanogenic Archaea that convert acetate to methane, by catalyzing the central reaction of C-C bond cleavage which serves as acetyl donor substrate reacting at ACDS beta subunit active site. properties Ni site A-cluster from Methanosarcina thermophila were investigated. A recombinant, C-terminally truncated form was employed, mimics native previously isolated complex, and contains composed...

We have built a high-resolution high-efficiency superconducting soft x-ray spectrometer for synchrotron-based fluorescence-detected absorption spectroscopy. The sensor is 3×3 array of 200×200 μm2 Nb–Al–Al2O3–Al–Nb tunnel junctions with an energy resolution around 15 eV below 1 keV and total count rate capability ≈100 000 counts/s. This cooled to ≈0.1 K by two-stage adiabatic demagnetization refrigerator while held at the end 40-cm-long cold finger that can be inserted into UHV sample chamber...

X-ray magnetic circular dichroism (XMCD), small-angle neutron scattering (SANS), and ac susceptibility $({\ensuremath{\chi}}_{\mathit{ac}})$ measurements as a function of temperature field on the Laves phase compound $\mathrm{Er}{\mathrm{Co}}_{2}$ are presented. The results allow one to investigate in detail paramagnetic phase. XMCD data reveal an extended region diagram where net magnetization Er Co sublattices oriented opposite directions at temperatures well above ferrimagnetic ordering...

This paper presents a wide-V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in</sub> step-down parallel-resonant converter (PRC), comprising an integrated 5-bit capacitor array and 300-nH resonant coil, placed in parallel to conventional buck converter. Soft-switching converters are beneficial for high-V multi-MHz reduce dominant switching losses, enabling higher frequencies. The output filter inductor is optimized based on empirical study of...

The authors report on the radiation from infinite dipole arrays printed ferrite substrates. Ferrite materials offer unique design capabilities at microwave frequencies because some of their properties depend DC magnetic field applied to them. performance an array elements depends strongly on, among other things, modes supported by substrate. nature grounded substrate and relation scan such substrates are described. Both in-plane perpendicular bias considered, a scheme dynamic biasing is...

Purpose: Inverse geometry computed tomography (IGCT) has been proposed as a new system architecture that combines small detector with large, distributed source. This can suppress cone‐beam artifacts, reduce scatter, and increase dose efficiency. However, the temporal resolution of IGCT is still limited by gantry rotation time. Large reductions in time are turn difficult due to large source array associated power electronics. We examine feasibility using stationary arrays for order achieve...

Electromagnetic navigation bronchoscopy (ENB) provides improved targeting accuracy during transbronchial biopsies of suspicious nodules. The greatest weakness ENB-based guidance is the registration divergence that exists between planning CT, acquired days or weeks before intervention, and patient on table day intervention. Augmenting ENB with real-time tomosynthesis imaging intervention could mitigate further improve yield ENB-guided biopsies. prototype, scanning-beam digital x-ray (SBDX)...

Scanning-beam digital x-ray (SBDX) is an inverse geometry fluoroscopy system for low dose cardiac imaging. The use of a narrow scanned beam in SBDX reduces detected scatter and improves efficiency, however the tight collimation also limits maximum achievable fluence. To increase fluence available imaging, we have constructed new prototype with wider beam, larger-area detector, real-time image reconstructor. Imaging performed scanning source that generates 40,328 overlapping projections from...

Fast switching power supplies allow to reduce the size and cost of external passive components. However, capacitive losses stage will increase become dominant part total losses. Therefore, resonant topologies are known key stage. A switch with an additional circuit can be turned on under soft-switching conditions, ideally zero-voltage-switching (ZVS). As conventional converts only efficient for a constant load, this paper presents predictive regulation loop approach conditions varying load...

Position-sensitive avalanche photodiodes (PSAPDs) are a promising alternative to photomultiplier tubes for the development of new generation gamma imagers. They offer compactness, high gain and superior quantum efficiency. PSAPDs having sensitive surface up 28times28 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> have been fabricated. However, unlike pixellated imaging devices similar configuration, each PSAPD can achieve...

We have developed and tested a pixelated detector for pinhole SPECT. The 80/spl times/80 has pixel size of 2.5/spl times/2.5 mm/sup 2/ incorporates the room-temperature solid-state semiconductor CdZnTe which offers direct charge conversion good stopping power radionuclides used small animal To optimize low energy photon detection, is operated at temperature 15/spl plusmn/1/spl deg/C, been designed to minimize absorption losses photons entering active material. demonstrates uniformity,...

Significant effort is currently being devoted to the development of noninvasive imaging systems that allow in vivo assessment biological and biomolecular interactions mice other small animals. Ideally, one would like discern these functional metabolic relationships with radionuclide at spatial resolutions approaching those can be obtained using anatomical techniques (<i>i.e.</i>, <100 &#956;m, which help answer outstanding questions many areas biomedicine. In this paper, we report progress...

Position-sensitive avalanche photodiodes (PSAPDs) have recently been proposed as optical light detectors in scintillation based gamma cameras. They are compact solid-state devices that provide high quantum efficiency and gain, they can achieve precise positioning over relatively large surfaces with few readout channels. In previous studies, PSAPDs were coupled to scintillator arrays the imaging task consisted identifying crystal of interaction. this paper, we investigate possibility using a...