Design considerations for a monolithic, GaAs, dual-mode, QPSK/QASK, high-throughput rate transceiver

A monolithic, GaAs, dual mode, quadrature amplitude shift keying and quadrature phase shift keying transceiver with one and two billion bits per second data rate is being considered to achieve a low power, small and ultra high speed communication system for satellite as well as terrestrial purposes. Recent GaAs integrated circuit achievements are surveyed and their constituent device types are evaluated. Design considerations, on an elemental level, of the entire modem are further included for monolithic realization with practical fabrication techniques. Numerous device types, with practical monolithic compatability, are used in the design of functional blocks with sufficient performances for realization of the transceiver

Advanced digital modulation: Communication techniques and monolithic GaAs technology

Communications theory and practice are merged with state-of-the-art technology in IC fabrication, especially monolithic GaAs technology, to examine the general feasibility of a number of advanced technology digital transmission systems. Satellite-channel models with (1) superior throughput, perhaps 2 Gbps; (2) attractive weight and cost; and (3) high RF power and spectrum efficiency are discussed. Transmission techniques possessing reasonably simple architectures capable of monolithic fabrication at high speeds were surveyed. This included a review of amplitude/phase shift keying (APSK) techniques and the continuous-phase-modulation (CPM) methods, of which MSK represents the simplest case

Dislocation generation and propagation during flash lamp annealing

Dislocation generation and propagation during flash lamp annealing for 20 ms was investigated using wafers with sawed, ground, and etched surfaces. Due to the thermal stress resulting from the temperature profiles generated by the flash pre-existing dislocations propagate into the wafer from both surfaces during flash lamp annealing. A dislocation free zone was observed around 700 μm depth below the surface of a 900 μm thick sawed wafer. The dislocation propagation can be well described by a three-dimensional mechanical model. It was further demonstrated that in wafers being initially free of dislocations no dislocations are generated during flash lamp annealing

On the Impact of Strained PECVD Nitride Layers on Oxide Precipitate Nucleation in Silicon

PECVD nitride layers with different layer stress ranging from about 315 MPa to −1735 MPa were deposited on silicon wafers with similar concentration of interstitial oxygen. After a thermal treatment consisting of nucleation at 650°C for 4 h or 8 h followed annealing 780°C 3 h + 1000°C 16 h in nitrogen, the profiles of the oxide precipitate density were investigated. The binding states of hydrogen in the layers was investigated by FTIR. There is a clear effect of the layer stress on oxide precipitate nucleation. The higher the compressive layer stress is the higher is a BMD peak below the front surface. If the nitride layer is removed after the nucleation anneal the BMD peak below the front surface becomes lower. It is possible to model the BMD peak below the surface by vacancy in-diffusion from the silicon/nitride interface. With increasing duration of the nucleation anneal the vacancy injection from the silicon/nitride interface decreases and with increasing compressive layer stress it increases. © The Author(s) 2019

Inter-individual Variation in Cancer and Cardiometabolic Health Outcomes in Response to Coffee Consumption : a Critical Review

Funding Sources None declared. Conflict of Interest None declared. Author Contributions E.V. and B.d.R. designed the study. E.V. created the search strategy under the supervision of B.d.R.E.V. and B.d.R. conducted the literature search, evaluated articles, and interpreted the data. E.V. drafted the manuscriptand B.d.R and J.M.G. reviewed and revised the article.Peer reviewedPostprin

Editors' Choice - Precipitation of Suboxides in Silicon, their Role in Gettering of Copper Impurities and Carrier Recombination

This paper describes a theoretical investigation of the phase composition of oxide precipitates and the corresponding emission of self-interstitials at the minimum of the free energy and their evolution with increasing number of oxygen atoms in the precipitates. The results can explain the compositional evolution of oxide precipitates and the role of self-interstitials therein. The formation of suboxides at the edges of SiO2 precipitates after reaching a critical size can explain several phenomena like gettering of Cu by segregation to the suboxide region and lifetime reduction by recombination of minority carriers in the suboxide. It provides an alternative explanation, based on minimized free energy, to the theory of strained and unstrained plates. A second emphasis was payed to the evolution of the morphology of oxide precipitates. Based on the comparison with results from scanning transmission electron microscopy the sequence of morphology evolution of oxide precipitates was deduced. It turned out that it is opposite to the sequence assumed until now. © 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited

Features of atomic and molecular beams passage through capillary systems in the presence of evanescent light waves

A model of the transverse cooling of atoms in the field of a surface light wave inside a glass capillary is considered. The attenuation coefficient for transverse oscillations of atom in a microcapillary is estimated, and the length of effective atom cooling is calculated. A 3D model is constructed. The possibility for the practical application of this phenomenon both to develop the technology of atomic lithography and to fabricate the nanostructures is considered

Benchmarking of the Current Solid Waste Management System in Karbala, Iraq, Using Wasteaware Benchmark Indicators

Solid waste management (SWM) poses severe problems to the authorities of the city of Kerbala, one of the main tourism centres in Iraq. Due to the city’s limited funds, it is crucial to evaluate the priorities for improvements in SWM services to tackle this problem efficiently. This paper employed Wasteaware benchmark indicators for integrated and sustainable solid waste management to evaluate the city SWM system performance. The data used in this evaluation was collected by in-depth interviews with the management authorities and field observations over two months in 2016. The outcomes showed that the SWM system in the city is weak. It therefore requires several improvements in physical infrastructure and management. Disposal and recycling were the highest priority to be improved among SWM physical components. While, in the management, the authority should have clear strategy for SWM and stakeholders such as public, private waste sector, and informal waste collectors should be included in SWM planning to improve the management services. This study can provide a starting point for the city authorities to prioritise their actions to improve the current SWM system

Investigating municipal solid waste management system performance during the Arba’een event in the city of Kerbala, Iraq

Every year, many religious events attended by 300 million pilgrims take place in many holy cities and sites around the world. However, research on municipal solid waste is limited despite the reputation of religious events to generate substantial amounts of waste. This research aims to address this gap and contribute to new knowledge on municipal solid waste management at religious events by investigating and evaluating the municipal solid waste management system applied at the Arba’een event in Kerbala, one of the largest religious events in Iraq. Field observations and in-depth interviews with nine senior managers from Kerbala’s municipalities were conducted during the event in 2016, to develop an overall picture of the municipal solid waste management system applied during the event. The data were analysed using thematic analysis and fed to the ‘Wasteaware’ benchmark indicators framework to evaluate the performance of the event system. The results indicated that the system suffers from operational and governance weaknesses. Despite a focus on municipal solid waste collection and transportation, the collection coverage is only ~ 70%. There is no controlled landfill site in Kerbala. It is estimated that currently ~ 5% of the event municipal solid waste is recycled by informal recyclers: there is no formal recycling scheme. Kerbala does not perform well regarding governance. The inclusivity of providers and users of the municipal solid waste management services is minimal during the event, as the majority of stakeholders are not included in decision-making processes. Municipal solid waste management services are delivered free of charge, thus significantly influencing the financial sustainability of the system. This study recommends that MSW recycling should be encouraged through integrating the informal sector, improving public awareness and introducing a formal recycling scheme to make the event municipal solid waste management system effective and financially sustainable