A5062528515- Semiconductor Quantum Structures and Devices
- Scientific Measurement and Uncertainty Evaluation
- Chemical Thermodynamics and Molecular Structure
- Air Quality and Health Impacts
- Radio Frequency Integrated Circuit Design
- Air Quality Monitoring and Forecasting
- Semiconductor materials and devices
- Toxic Organic Pollutants Impact
- Atmospheric chemistry and aerosols
- Analytical chemistry methods development
- GaN-based semiconductor devices and materials
- solar cell performance optimization
- Vehicle emissions and performance
- Mercury impact and mitigation studies
- Analytical Chemistry and Chromatography
- Nanowire Synthesis and Applications
- Heavy metals in environment
- Pesticide Residue Analysis and Safety
- Odor and Emission Control Technologies
- Advanced Chemical Sensor Technologies
- Geochemistry and Geologic Mapping
- Phase Equilibria and Thermodynamics
- Advanced Semiconductor Detectors and Materials
- Semiconductor materials and interfaces
- Calibration and Measurement Techniques
National Physical Laboratory
2013-2025
St Vincents Institute of Medical Research
2023
RTX (United States)
2011-2022
University Hospitals of Morecambe Bay NHS Foundation Trust
2017-2022
University of Virginia
2022
University of Illinois Chicago
2022
Envigo (United States)
2021
Environment Agency
2021
Monash Health
2019
Monash University
2019
An advanced high power, frequency GaN semiconductor process has made possible the design and fabrication of W-band power amplifier MMICs with unprecedented performance. The key enabling technology is a 150 nm T-gate HEMT an output exceeding 300 mW peak PAE (power added efficiency) 37%. With this process, have been designed fabricated that demonstrate powers 1.7 watts, efficiencies greater than 20%, small signal gains 21 dB. In addition, compactness these MMIC designs allowed for densities...
Summary form only given, as follows. An advanced GaN semiconductor process has made possible the design and fabrication of W-band power amplifier MMICs with unprecedented performance. Power have been designed fabricated that demonstrate output powers 1.7 watts, added efficiencies greater than 20%, small signal gains 21 dB. In addition, compactness these MMIC designs allowed for densities (MMIC relative to area) exceeding 1/2 watt per square mm.
The Antlers aquifer, which consists of as much 900 feet friable sandstone, silt, clay, and shale crops out in areas 1 ,860 square miles underlies about 4,400 southeastern Oklahoma. Precipitation ranges from 34 to 50 inches per year across the outcrop area is well suited allow high rates infiltration. aquifer contains an estimated 70 ,000,000 acre-feet water having less than 1,000 milligrams liter dissolved solids. average saturated thickness 250 feet. Aquifer tests indicate transmissivity...
The purpose of this study was to identify a characteristic elemental tyre fingerprint that can be utilised in atmospheric source apportionment calculations. Currently zinc is widely used as single element tracer quantify wear, however several authors have highlighted issues with approach. To overcome this, rubber tread digested and has been analysed for 25 elements by ICP-MS generate multielement profile. Additionally, estimate the percentage made up inert fillers, thermogravimetric analysis...
Abstract In conventional p – n junction solar cells, carrier multiplication by impact ionisation, is negligible, owing to the low temperature of electron–hole pairs. This leads particle conservation between net number absorbed photons and pairs withdrawn from cell. hot‐carrier in which electrons are at a high assuming suppression electron–phonon scattering, such peculiar results. Numerical calculations show that entire current–voltage characteristics with meaningful values chemical potential...
In the past, minimal improvements have been predicted for efficiency enhancement of solar cells using impurity photovoltaic (IPV) effect, where optical excitation through midgap defect levels allows use long wavelength photons to increase conversion sunlight electricity. present work, principle detailed balance is used calculate limiting with inclusion in idealized case when all transitions are assumed be radiative. Based on these calculations, IPV device a large number different species...
Variations in the composition of faunal assemblages streams are often associated with changes areas substrate. An observer walking along bank finds these easy to distinguish and we have used as our basic ecological unit. Essentially unit is visually distinct from called it a mesohabitat introduce scalar dimension which term biotope does not microhabitats such leaf tip or stone surface macrohabitats might include whole reach river. We wished test hypothesis that mesohabitats support specific...
The most widely used method for the preparation of primary standard gas mixtures involves weighing individual components into a cylinder. We present new mathematical description and its uncertainties. use this to demonstrate how strategies serial dilution can be identified that minimize uncertainty in final mixture show they implemented practically. review published reports high accuracy gravimetry give examples relative uncertainties composition standards approaching 1 part-per-million best...
The extent of correlation in polycyclic aromatic hydrocarbon (PAH) concentration data obtained by the UK PAH Monitoring and Analysis Air Quality Network from March 2008 to November 2010 has been assessed. Application principal component analysis (PCA) dataset revealed that concentrations vast majority PAHs are very highly correlated. use diagnostic ratios (including a new benzo[b]naph[2,1-d]thiophene/benzo[a]pyrene ratio), novel 'combined ratio – PCA' approach information about main sources...
A tunable G-band frequency-modulated continuous-wave radar system has been developed and used to perform differential absorption atmospheric humidity measurements for the first time. The radar's transmitter uses high- power-handling GaAs Schottky diodes generate between 15-23 dBm over a 10-GHz bandwidth near 183 GHz. By virtue of high-isolation circular polarization duplexer, monostatic receiver maintains noise figure about 7 dB even while is on. With an antenna gain 40 dB, high-SNR...
Abstract Tandem stacks of solar cells have clearly shown their ability to increase the efficiency energy conversion. In past, challenge in making these devices often has been materials science area, working around constraints imposed by different meet requirements lattice constant and bandgap. However, developments field low‐dimensional structures; particularly superlattices, may allow generic approaches developing tandem large numbers cells. The current flowing through such will be...
Secondary organic matter (SOM) formed from gaseous precursors constitutes a major mass fraction of fine particulate matter. However, there is only limited evidence on its toxicological impact. In this study, air–liquid interface cultures human bronchial epithelia were exposed to different series fresh and aged soot particles generated by miniCAST burner combined with micro smog chamber (MSC). Soot cores geometric mean mobility diameters 30 90 nm coated increasing amounts SOM, the...
Lead isotope ratios vary depending on the origin of lead, meaning that characteristic isotopic signatures can be used for source identification in environmental samples. ambient particulate matter was collected and analysed at 23 monitoring stations as part UK heavy metals air quality network to assess compliance with legislative limit values allowable concentrations lead air. For first time a nationwide basis, analysis carried out these samples gain further information about sources...
Near real-time data across taxa are necessary for quantifying biodiversity at regional to continental scales and evaluating conservation measures. Yet, standardized methods globally distributed infrastructure still lacking. In this study, we conducted the first national survey of terrestrial using a metabarcoding approach on airborne environmental DNA collected by ambient air quality monitoring network. Our goal was perform multi-taxonomic assessment scale, compare detections with those...
Abstract Following recent progress in the study of limiting efficiencies photovoltaic devices with multiple energy levels, we suggest using impurity (IPV) effect wide‐bandgap semiconductors as a means to achieve very‐high‐efficiency solar cells. We discuss requirements for high‐efficiency IPV device and review some material systems that could be used. As case study, investigate theoretically β‐SiC cells model based on modified Shockley–Read–Hall theory. The potential is confirmed important...
The Chattanooga shale contains insoluble organic matter (kerogen) derived from terrestrial (humic) and marine (sapropelic) sources. Kerogen sapropelic sources more hydrogen than kerogen humic Thus the content of contribution, kerogen, increases toward that part a most likely to be source bed for petroleum. Uranium in is adjoining land mass.
An advanced high power, frequency GaN semiconductor process has been used to design performance E-band power amplifier MMICs demonstrating unprecedented output PAE and reliability. To the author's knowledge, these designs demonstrate beyond previously published results for MMICs.