Search

Finding the source location of a radio-frequency (RF) transmission is a useful capability for many civilian, industrial, and military applications. This problem is particularly challenging when done “Blind,” or when the transmitter was not designed with finding its location in mind, and relatively little information is available about the signal before-hand. Typical methods for this operation utilize the time, phase, power, and frequency viewable from received signals. These features are all less predictable in indoor and urban environments, where signals undergo transformation from multiple interactions with the environment. These interactions imprint structure onto the received signal which is dependent on the transmission path, and therefore the initial location. Using a received signal, a signal characteristic known as the autocorrelation can be computed which will largely be shaped by this information. In this research, RF source localization using finger-printing (a technique involving matching to a known database) with signal autocorrelations is explored. A Gaussian-process-based method for autocorrelation based fingerprinting is proposed. Performance of this method is evaluated using a ray-tracing-based simulation of an indoor environment.

It has been suggested that the wireless network evolution to smaller carrier wavelengths (from 2G to 5G) increases radio frequency electromagnetic field (RF-EMF) absorption in western honey bees (Apis mellifera). It is unknown whether the radiation performance of antennas is stable when an insect appears in their vicinity. In this research, the absorbed power in a worker honey bee and the influence of the bee's presence on antennas' radiation performance are investigated for the newly used frequencies in 5G networks from 6 to 240 GHz. To these aims, numerical simulations using the finite-difference time-domain (FDTD) method were performed, in which a bee model, obtained by micro-CT scanning, was employed. These simulations showed that, in the near field, the absorbed power can increase by a factor of 53 from 6 to 240 GHz. This is a factor of 7 higher than the increase reported in the far-field in previous studies. Furthermore, the simulations revealed that antennas' radiation efficiency can decrease by up to -40% when a bee appears in the near field. Likewise, it was found that the gain pattern depends on the separation distance between the bee and the antenna with a stronger dependency for higher frequencies.

Convolutional neural networks (LeCun and Bengio 1998 The Handbook of Brain Theory and Neural Networks 255–58; LeCun, Bengio and Hinton 2015 Nature 521 436–44) are state-of-the-art and ubiquitous in modern signal processing and machine vision. Nowadays, hardware solutions based on emerging nanodevices are designed to reduce the power consumption of these networks. This is done either by using devices that implement convolutional filters and sequentially multiply consecutive subsets of the input, or by using different sets of devices to perform the different multiplications in parallel to avoid storing intermediate computational steps in memory. Spintronics devices are promising for information processing because of the various neural and synaptic functionalities they offer. However, due to their low OFF/ON ratio, performing all the multiplications required for convolutions in a single step with a crossbar array of spintronic memories would cause sneak-path currents. Here we present an architecture where synaptic communications are based on a resonance effect. These synaptic communications thus have a frequency selectivity that prevents crosstalk caused by sneak-path currents. We first demonstrate how a chain of spintronic resonators can function as synapses and make convolutions by sequentially rectifying radio-frequency signals encoding consecutive sets of inputs. We show that a parallel implementation is possible with multiple chains of spintronic resonators. We propose two different spatial arrangements for these chains. For each of them, we explain how to tune many artificial synapses simultaneously, exploiting the synaptic weight sharing specific to convolutions. We show how information can be transmitted between convolutional layers by using spintronic oscillators as artificial microwave neurons. Finally, we simulate a network of these radio-frequency resonators and spintronic oscillators to solve the MNIST handwritten digits dataset, and obtain results comparable to software convolutional neural networks. Since it can run convolutional neural networks fully in parallel in a single step with nano devices, the architecture proposed in this paper is promising for embedded applications requiring machine vision, such as autonomous driving.

Planar transmission line on silicon substrate imposes certain challenges at higher frequencies and measurement of the same employing wafer probing techniques needs accurate characterization. Wafer measurement provides information related with the device performance which in turn helps to minimize parasitic related with package and assembly. Wafer probing at higher frequencies imposes certain challenges more so ever on silicon substrate. Silicon substrate due to semiconductor in nature is a lossy medium for radio frequencies and standard wafer is not suitable for the realization of RF circuits. Present article demonstrate realization of planar transmission line on high resistivity silicon substrate by employing thick oxide layer. Both simulated and measured results are presented in this article and the CPW line fabricated with the proposed process results in ~1dB loss with better than 12dB return loss at Ka-band. Measurement techniques for the line characterization are detailed in this article along with transmission line characterization at Ka-band.

In this article, based on the developed methodology, the stages of designing two designs of high-performance radio-frequency single-pole single-throw microelectromechanical switches are investigated. These radio-frequency microelectromechanical switches are designed to operate at a central resonant frequency of 3.6 GHz and 3.4 GHz, respectively, as well as to work both in mobile communication devices and in the design of the architecture of 5G mobile networks, in particular in arrays of integrated antennas and radio-frequency interface modules. The manufacture and study of two designed structures are researched. For the first manufactured experimental sample in the open state the insertion loss is no more than −0.69 dB and the reflection loss is −28.35 dB, and in the closed state the isolation value is at least −54.77 dB at a central resonant frequency of 3.6 GHz. For the second in the open state the value of the insertion loss is no more than −0.67 dB and the reflection loss is −20.7 dB, and in the closed state the isolation value is not less than −52.13 dB at the central resonant frequency of 3.4 GHz. Both manufactured experimental samples are characterized by high linearity, as well as a small value of contact resistance in the closed state.

Mini-invasive techniques in medicine are the novel paradigm to achieve good treatment results while keeping the patient at ease and avoid heavy and painful application of standard techniques. This is the case of tumor treatment, with special reference to organs such as liver, lung, kidney. In this case, the application of a well-localized heat source can destroy tumor cells by means of a necrotic process. Such techniques are based on different technologies: Radio Frequency and Microwave are the most common ones. Nevertheless, several open issues are still present as the optimal choice of application time, the definition of the burning area, the best stimulus signal to be applied, the modeling of the target area concerning its electric/magnetic properties whose values can evolve during treatment. For all these reasons, and not limited to, the role of engineers is crucial to obtain better performance with limited amount of energy and limited side effects for the patient. Particularly, the measurement open issues and how such issues could lead to an enhancement of the industrial production processes of needed apparatuses are reported in this paper.

Orientador: Jacobus Willibrodus Swart Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Resumo: O aumento no número de usuários, assim como a demanda por maior taxa de transferência de dados, está impulsionando o desenvolvimento de novas tecnologias, uma vez que o padrão clássico de comunicação está atingindo sua saturação. Vídeos em alta definição, chamadas em vídeo-conferência e downloads em alta velocidade deixaram de ser uma particularidade para se tornarem básicos, oferecendo constantes desafios em todos os níveis de projeto de um dispositivo. Atualmente, a maneira adotada para se criar um canal de comunicação sem fio (wireless) baseia se na modulação da informação de interesse em torno de uma freqüência muito mais alta, chamada portadora. Para cada protocolo tem-se reservada uma banda do espectro, porém, dependendo da região e do número de usuários dividindo a banda, tende-se a ter esta banda saturada, reduzindo a capacidade de comunicação para cada usuário. Freqüentemente, observam-se cenários onde algumas bandas de freqüência estão extremamente ocupadas e regiões vizinhas no espectro completamente vazias. De modo a operar o espectro com maior inteligência, surgiram conceitos com o de Rádios Cognitivos (CR - Cognitive Radios), onde algoritmos monitoram o espectro de modo a utilizar um canal somente quando este estiver livre, mudando de banda se necessário. Isto requer circuitos susceptíveis à operação em banda larga. Sendo assim, este projeto propõe a realização de um amplificador de banda larga empregando um novo método de cancelamento de ruído, além do projeto de um misturador de baixo ruído utilizando técnicas recentes exploradas na literatura, de modo a obter uma cadeia de recepção para uso em banda larga. O LNA apresenta casamento de impedância e ganho de potência de 12dB na banda de 50 MHz até 5 GHz, com NF variando de 1,4 - 2,4 dB, enquanto consome 15 mW de potência sob tensão de alimentação de 1,5 V. O desempenho em NF, quando levado em consideração a potência consumida e o nó tecnológico, é o melhor comparado aos recentes projetos que o autor tem conhecimento. O cancelamento de ruído é obtido através de uma condição específica do circuito, requerendo uma corrente extra de polarização, já inclusa na potência total do circuito. Para compor a cadeia de recepção e, consecutivamente, a conversão do sinal em banda base de modo homodyne, projetou-se um par de Misturadores de modo a re-utilizar a corrente extra requerida pelo LNA no cancelamento do ruído. Desta maneira, obteve-se na cadeia de recepção o ganho de tensão de 26 dB na saída de cada Misturador, em Fase (I) e Quadratura (Q), para uma banda de 50 MHz até 6,5 GHz, com SSB NF variando de 6,1 - 9,2 (3,1 - 6,2 dB para DSB), consumindo os mesmos 15 mW e tendo a banda estendida pelos Misturadores. Os circuitos foram fabricados na tecnologia UMC 0,13'mu'm Mixed/RF CMOS e algumas medidas preliminares foram obtidas e serão mostradas nesta dissertação. O LNA apresentou ganho, casamento de impedância e potência próximos aos valores obtidos nas simulações, mostrando boa confiabilidade dos valores projetados Abstract: The increase in the number of users as well as the demand for higher data transfer rate is driving development of new technologies, since the classical communication is reaching its saturation. Videos in high definition, video-conference calls and high-speed downloads are no longer a special feature to become basic, offering constant challenges at all levels in the design of a device. Currently, the way adopted to create a wireless communication channel is based on the modulation of interesting information about a much higher frequency, called carrier. For each protocol, a reserved bandwidth of the spectrum has been assigned, however, depending on the region and the number of users sharing the band, it tends to have saturated the band, reducing the communication ability of each user. Often, there are scenarios where some bands are extremely busy and neighboring regions in the spectrum are completely empty. In order to operate the spectrum with higher intelligence emerged with the concept of Cognitive Radio (CR), where algorithms monitor the channel in order to use them only when it is free, and changing band if necessary. This requires circuits to be susceptible for broadband operation. Therefore, this project proposes a broadband amplifier using a new method for noise cancellation, and the design of a low noise mixer using techniques explored in the recent literature, in order to get broadband receiver chain. The LNA provides impedance matching and power gain of 12dB from 50MHz to 5GHz band with NF ranging from 1.4 - 2.4 dB, while consuming 15mW of power under a supply voltage of 1.5 V. Its NF performance, when taken into consideration the power consumption and technology node, is the best compared to recent projects that the author is aware of. The noise cancellation is achieved by a specific condition of the circuit, requiring an extra biasing current, already included in the total circuit power. To compose the chain of reception and, consecutively, the conversion of the baseband signal in homodyne mode, a pair of Mixers were designed, re-using the extra current required by the LNA for noise cancellation. Thus, it was achieved at receiver chain a voltage gain of 26dB at the output of each Mixer, at Phase (I) and Quadrature (Q), for bandwidth of 50MHz to 6.5 GHz with SSB NF ranging from 6.1 - 9.2 (3.1 - 6.2dB for DSB), also consuming the same 15mW and having a band enhancement provided by the Mixers. The circuits were fabricated in UMC technology 0.13'mu'm Mixed/RF CMOS and some preliminary measurements were obtained and are shown in this dissertation. The LNA presented gain, impedance matching and power close to the values obtained in the simulations, showing good reliability on the projected values Mestrado Eletrônica, Microeletrônica e Optoeletrônica Mestre em Engenharia Elétrica

SPIDER radio-frequency (RF) inductively coupled ion source is a full-size prototype of ITER Heating Neutral Beam Injector ion source,equipped with 100 keV accelerator system for the particles. It is in operation since June 2018 in the premises of Neutral Beam Test Facility located in Padova, Italy. The ion source includes a plasma source where plasma is generated and heated by8 RF drivers operating with Hydrogen/Deuterium at a gas pressure of ~ 0.3 Pa and maximum RF power of 100 kW per driver at 1 MHz frequency. There are 4RF circuits present in SPIDER, each comprises of a RF generator and a RF load. The RF load is defined bya transmission line:a capacitor-basedmatching network and two driver coils connected in series. To qualify the performance of the driver, an estimation of the power transfer efficiency (PTE) to the plasma is important. It is defined as the ratio between the power absorbed by the plasma and the total RF input power. The power absorbed by the plasma cannot be measured experimentally and is found to be dependent on several parameters coupled together. Previously, a methodology has been developed based on the integration of various input parameters, plasma heating mechanisms and an electrical model which can provide an estimation of PTE to the plasma. One of the essential input parameters is the plasma electron density.It is possible to experimentally measure this parameter and currently different methods are being explored,but usually they also require a detailed and time consuming data analyses. In this perspective, are liable and a fast model will be beneficial for the estimation of electron density. This work will focus on the description, application,and comparison of different ways to estimate the electron density.Based on the available literature, two main approaches are highlighted for the estimation of electron density1) from the power balance equation and 2) through the measurements of the electrical parameters in the RF power circuits.The results in terms of electron density will be compared to the first experimental results obtained from spectroscopic and/or electrostatic probe measurements.

Radiofrequency electromagnetic fields (EMFs) are used to enable a number of modern devices, including mobile telecommunications infrastructure and phones, Wi-Fi, and Bluetooth. As radiofrequency EMFs at sufficiently high power levels can adversely affect health, ICNIRP published Guidelines in 1998 for human exposure to time-varying EMFs up to 300 GHz, which included the radiofrequency EMF spectrum. Since that time, there has been a considerable body of science further addressing the relation between radiofrequency EMFs and adverse health outcomes, as well as significant developments in the technologies that use radiofrequency EMFs. Accordingly, ICNIRP has updated the radiofrequency EMF part of the 1998 Guidelines. This document presents these revised Guidelines, which provide protection for humans from exposure to EMFs from 100 kHz to 300 GHz. Health Phys. 118(5):483–524; 2020. Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Health Physics Society. This is an open-access article distributed under the terms of the Creative Commons AttributionNon Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

In this paper, surrogate modeling techniques are applied for passive component modeling. These techniques are exploited to develop and compare two alternative strategies for automated radio-frequency (RF) circuit design. The first one is a traditional approach where passive components are designed during the optimization stage. The second one, inspired on bottom-up circuit design methodologies, builds passive component Pareto-optimal fronts (POFs) prior to any circuit optimization. Afterwards, these POFs are used as an optimized library from where the passive components are selected. This work exploits the advantages of evolutionary computation algorithms in order to efficiently explore the circuit design space, and the accuracy and efficiency of surrogate models to model passive components.

The ITER Ion Cyclotron Resonance Heating (ICRH) system is designed to couple to the plasma 20 MW of RF power from two antennas in the 40-55 MHz frequency range during long pulses of up to 3600 s and under various plasma conditions with Edge Localized Modes. Radio-Frequency (RF) contacts are integrated within the ITER ICRH launcher in order to ensure the RF current continuity and ease the mechanical assembly by allowing the free thermal expansion of the Removable Vacuum Transmission Line coaxial conductors during RF operations or during 250{\textdegree}C baking phases. A material study has been carried out to determine which materials and associated coatings are relevant for RF contacts application in ITER. In parallel, RF tests have been performed with a new prototype of Multi-Contact (r) LA-CUT/0,25/0 contacts made of silver-coated CuCrZr louvers. During these tests on a RF vacuum resonator, currents between 1.2 kA and 1.3 kA peak have been reached a few tens of times in steady-state conditions without any visible damage on the louvers. A final 62MHz pulse ending in a 300s flat top at 1.9kA resulted in severe damage to the contact. In addition, a test bed which performs sliding test cycles has been built in order to reproduce the wear of the contact prototype after 30 000 sliding cycles on a 3 mm stroke at 175{\textdegree}C under vacuum. The silver coating of the louvers is removed after approximately a hundred cycles whilst, to the contrary, damage to the CuCrZr louvers is relatively low., Fusion Engineering and Design, Elsevier, A Para{\^i}tre

Human activity monitoring is essential for a variety of applications in many fields, particularly healthcare. The goal of this research work is to develop a system that can effectively detect fall/collapse and classify other discrete daily living activities such as sitting, standing, walking, drinking, and bending. For this paper, a publicly accessible dataset is employed, which is captured at various geographical locations using a 5.8 GHz Frequency-Modulated Continuous-Wave (FMCW) RADAR. A total of ninety-nine participants, including young and elderly individuals, took part in the experimental campaign. During data acquisition, each aforementioned activity was recorded for 5–10 s. Through the obtained data, we generated the micro-doppler signatures using short-time Fourier transform by exploiting MATLAB tools. Subsequently, the micro-doppler signatures are validated, trained, and tested using a state-of-the-art deep learning algorithm called Residual Neural Network or ResNet. The ResNet classifier is developed in Python, which is utilised to classify six distinct human activities in this study. Furthermore, the metrics used to analyse the trained model’s performance are precision, recall, F1-score, classification accuracy, and confusion matrix. To test the resilience of the proposed method, two separate experiments are carried out. The trained ResNet models are put to the test by subject-independent scenarios and unseen data of the above-mentioned human activities at diverse geographical spaces. The experimental results showed that ResNet detected the falling and rest of the daily living human activities with decent accuracy.

Conventional thawing processes adopted by food industry are characterized by longer operation times and food quality losses. Recently, batch and continuous radio-frequency (RF) assisted thawing were proposed as alternative and faster process, but their economic feasibility at industrial level is far to be assessed. Undoubtedly, longer penetration depth and ability to generate volumetric heat enable RF assisted heating a very promising technology to apply at industrial scale. On the other hand, most of the RF systems in operation are built following heuristic criteria, more than being designed and tailored on specific products or processes: this has limited the development of RF based system for food thawing as well as the proposal of simple but effective control systems. The literature has contributed with a number of theoretical and modeling based works for RF processes, but design-based studies in general are limited. Therefore, the objective of this study was to present a strategy for virtual design of a continuous RF thawing process. For this purpose, a previously developed and experimentally validated mathematical model was modified to take into account the movement of food product through a continuous RF system, the movement of RF electrode and subsequent effects of temperature and electric field changes. Power uniformity index (PUI) for various proposed configurations was analyzed, and possible scenarios were suggested for an industrial scale process. With this concept, this study was assumed to be significant for design and optimization of industrial RF and RF thawing processes. (C) 2017 Elsevier Ltd. All rights reserved.

Plasma-based surface modification is recognized as an effective way to activate biomaterial surfaces, and modulate their interactions with cells, extracellular matrix proteins, and other materials. However, treatment of a luminal surface of a tubular scaffold remains non-trivial to perform in small diameter tubes. Polyvinyl alcohol (PVA) hydrogel, which has been widely used for medical applications, lacks functional groups to mediate cell attachment. This poses an issue for vascular applications, as endothelialization in a vascular graft lumen is crucial to maintain long term graft patency. In this study, a Radio Frequency Glow Discharges (RFGD) treatment in the presence of NH3 was used to modify the luminal surface of 3-mm diameter dehydrated PVA vascular grafts. The grafted nitrogen containing functional groups demonstrated stability, and in vitro endothelialization was successfully maintained for at least 30 days. The plasma-modified PVA displayed a higher percentage of carbonyl groups over the untreated PVA control. Plasma treatment on PVA patterned with microtopographies was also studied, with only the concave microlenses topography demonstrating a significant increase in platelet adhesion. Thus, the study has shown the possibility of modifying a small diameter hydrogel tubular scaffold with the RFGD plasma treatment technique and demonstrated stability in ambient storage conditions for up to 30 days.

Quantum computation promises to solve presently intractable problems, with hopes of yielding solutions to pressing issues to society. Despite this, current machines are limited to tens of qubits. The field is in a state of continuous scaling, with groups around the world working on all aspects of this problem. The work of this thesis aims to contribute to this effort. It is motivated by the goal of increasing both the speed and bandwidth of experiments conducted within our laboratory. Low-loss radio-frequency multiplexers were characterised at cryogenic temperatures, with some shown to operate at below 7mK. The Analog Devices ADG904 was one of these, and its insertion loss was measured at

Background and Objective To evaluate safety and efficacy of focused monopolar radio frequency (RF) device for non-invasive labia tissue tightening and improvement of labial laxity. Methods This prospective cohort study participants were 17 female subjects aged between 27 and 56 years with lax skin at the labia area. All subjects received four consecutive treatments at 7-day intervals with RF device (Exilis Protege IntimaR, BTL Industries Inc., Boston, MA). The primary efficacy outcome measure was defined as one or more point improvement on 1–4 scale for vulva appearance determined by three blinded evaluators. Digital photographs were taken at the baseline and 1 month after the last treatment. Sexual gratification was assessed with Female Sexual Functioning Index (FSFI) and patient discomfort by Visual Analogue Scale (VAS). Results An average 2.9 (of maximum 4) points improvement rate in vulvar appearance was observed (P

In this review, the advances in radio-frequency (RF) /microwave chemical gas sensors using conducting polymers are discussed. First, the introduction of various conducting polymers is described. Only polyaniline (PANi), polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT), which are mainly used for gas sensors in RF/microwave region, are focused in this review. Sensing mechanism of the three conducting polymers are presented. And the RF/microwave characteristics and RF/microwave applications of the three conducting polymers are discussed. Moreover, the gas sensors using conducting polymers in RF/microwave frequencies are described. Finally, the the challenges and the prospects of the next generation of the RF/microwave based chemical sensors for wireless applications are proposed.

The physics of interactions between waves in plasmas and sheaths for background magnetic fields which make oblique angles with the sheath surfaces is studied with the use of the self-consistent finite element code rfSOL incorporating the recently developed sheath impedance model [J. R. Myra, Phys. Plasmas 24, 072507 (2017)]. The calculation based on this model employs the generalized sheath boundary condition (sheath BC), which surpasses the previously used capacitive sheath BC in reliability by taking into account the contributions of the ion and electron currents in the sheath as well as the displacement current. A series of numerical simulations is carried out in two-dimensional slab geometry with a flat or curved sheath surface as part of the boundary. For the plasma density higher than the lower hybrid resonance density (LHR density), it is shown that the sheath–plasma wave appears when the equilibrium magnetic field line angle with respect to the sheath surface is small, the absolute value of the radio-frequency (RF) sheath voltage is large, and the plasma density is low within the allowable range, all of which bring the sheath property closer to being capacitive. It is also shown that the sharp variation of the magnetic field line angle along the sheath surface can sensitively affect the maximum absolute value of the RF sheath voltage at a plasma density slightly lower than the LHR density.

Insects are continually exposed to Radio-Frequency (RF) electromagnetic fields at different frequencies. The range of frequencies used for wireless telecommunication systems will increase in the near future from below 6 GHz (2 G, 3 G, 4 G, and WiFi) to frequencies up to 120 GHz (5 G). This paper is the first to report the absorbed RF electromagnetic power in four different types of insects as a function of frequency from 2 GHz to 120 GHz. A set of insect models was obtained using novel Micro-CT (computer tomography) imaging. These models were used for the first time in finite-difference time-domain electromagnetic simulations. All insects showed a dependence of the absorbed power on the frequency. All insects showed a general increase in absorbed RF power at and above 6 GHz, in comparison to the absorbed RF power below 6 GHz. Our simulations showed that a shift of 10% of the incident power density to frequencies above 6 GHz would lead to an increase in absorbed power between 3–370%.

General interest has been shown over the last years for compact and more affordable facilities for hadron-therapy. The High-Gradient (HG) know-how and technology for normal-conducting accelerating RF (Radio-Frequency) electron linac (linear accelerator) structures recently developed for projects such as CLIC (CERN), has raised the achievable accelerating gradient from 20-30 MV/m up to 100-120 MV/m. This gain has come through a better understanding of the high-power RF vacuum arcs or breakdowns (BD) phenomena, the development of quantitative HG RF design methods and refinements in fabrication techniques. This can allow for more compact linacs also for protons, which is potentially important in the new trend in hadron-therapy of using linacs able to provide protons of 70-230 MeV or light ions of 100-400 MeV/u. Linacs are of particular interest for medical applications because they can provide a high degree of flexibility for treatment, such as running at 100-400 Hz pulse rate and pulse-to-pulse beam energy (and intensity) variations. This kind of accelerator is very well suited to treat moving organs with 4D multi-painting spot scanning technique. HG operation is limited by the BD phenomena and is characterized by the BD-Rate. New fresh structures initially operate at a reduced performance and must be conditioned through extended high-power rf operation until the maximum operational gradient is reached. This process is a time consuming, and consequently costly task (> 350 million pulses) which is important to understand and reduce. The IFIC HG-RF laboratory is designed to host a high-power and high-repetition rate facility for testing S-Band (2.9985 GHz) normal-conducting RF structures. This facility will allow the development, RF conditioning and studies of the BD phenomena in HG structures. General interest has been shown over the last years for compact and more affordable facilities for hadron-therapy. The High-Gradient (HG) know-how and technology for normal-conducting accelerating RF (Radio-Frequency) electron linac (linear accelerator) structures recently developed for projects such as CLIC (CERN), has raised the achievable accelerating gradient from 20-30 MV/m up to 100-120 MV/m. This gain has come through a better understanding of the high-power RF vacuum arcs or breakdowns (BD) phenomena, the development of quantitative HG RF design methods and refinements in fabrication techniques. This can allow for more compact linacs also for protons, which is potentially important in the new trend in hadron-therapy of using linacs able to provide protons of 70-230 MeV or light ions of 100-400 MeV/u. Linacs are of particular interest for medical applications because they can provide a high degree of flexibility for treatment, such as running at 100-400 Hz pulse rate and pulse-to-pulse beam energy (and intensity) variations. This kind of accelerator is very well suited to treat moving organs with 4D multi-painting spot scanning technique. HG operation is limited by the BD phenomena and is characterized by the BD-Rate. New fresh structures initially operate at a reduced performance and must be conditioned through extended high-power rf operation until the maximum operational gradient is reached. This process is a time consuming, and consequently costly task (> 350 million pulses) which is important to understand and reduce. The IFIC HG-RF laboratory is designed to host a high-power and high-repetition rate facility for testing S-Band (2.9985 GHz) normal-conducting RF structures. This facility will allow the development, RF conditioning and studies of the BD phenomena in HG structures.

Multiple Electrostatic Quadrupole Array Linear Accelerators (MEQALACs) provide an opportunity to realize compact radio-frequency (RF) accelerator structures that can deliver very high beam currents. MEQALACs have been previously realized with acceleration gap distances and beam aperture sizes of the order of centimeters. Through advances in Micro-Electro-Mechanical Systems (MEMS) fabrication, MEQALACs can now be scaled down to the sub-millimeter regime and batch processed on wafer substrates. In this paper, we show first results from using three RF stages in a compact MEMS-based ion accelerator. The results presented show proof-of-concept with accelerator structures formed from printed circuit boards using a 3x3 beamlet arrangement and noble gas ions at 10 keV. We present a simple model to describe the measured results. The model is then used to examine some of the aspects of this approach, such as possible effects of alignment errors. We also discuss some of the scaling behaviour of a compact MEQALAC. The MEMS-based approach enables a low-cost, highly versatile accelerator covering a wide range of beam energies and currents. Applications include ion-beam analysis, mass spectrometry, materials processing, and at very high beam powers, plasma heating., Comment: Conference on the Application of Accelerators in Research and Industry, CAARI 2016, 30 October-4 November 2016, Ft. Worth, TX, USA

The quality of graphene in nanodevices has increased hugely thanks to the use of hexagonal boron nitride as a supporting layer. This paper studies to which extent hBN together with channel length scaling can be exploited in graphene field effect transistors (GFETs) to get a competitive radio frequency (RF) performance. Carrier mobility and saturation velocity were obtained from an ensemble Monte Carlo simulator that accounted for the relevant scattering mechanisms (intrinsic phonons, scattering with impurities and defects, etc.). This information is fed into a self consistent simulator, which solves the drift diffusion equation coupled with the two dimensional Poisson's equation to take full account of short channel effects. Simulated GFET characteristics were benchmarked against experimental data from our fabricated devices. Our simulations show that scalability is supposed to bring to RF performance an improvement that is, however, highly limited by instability. Despite the possibility of a lower performance, a careful choice of the bias point can avoid instability. Nevertheless, maximum oscillation frequencies are still achievable in the THz region for channel lengths of a few hundreds of nanometers., Comment: 29 pages, 7 figures, 1 table, Supplementary Information (10 pages) Funded by: 1 Micronova Nanofabrication Centre 2 European Union's Horizon 2020 (696656) 3 MINECO (TEC2013-42622-R, TEC2015-67462-C2-1-R, TEC2016-80839-P, MINECO/FEDER, FJCI-2014-19643) 4 MECD (CAS16/00043) 5 Generalitat de Catalunya (2014 SGR 384)

Background Spontaneous magnetic alignment (SMA), in which animals position their body axis in fixed alignments relative to magnetic field lines, has been shown in several classes of vertebrates and invertebrates. Although these responses appear to be widespread, the functional significance and sensory mechanism(s) underlying SMA remain unclear. An intriguing example comes from observations of wild red foxes (Vulpes vulpes) that show a ~fourfold increase in hunting success when predatory ‘mousing’ attacks are directed toward magnetic north-northeast. This form of SMA is proposed to receive input from a photoreceptor-based magnetoreception mechanism perceived as a ‘visual pattern’ and used as a targeting system to increase the accuracy of mousing attempts targeting hidden prey. However, similar to previous observational studies of magnetic orientation in vertebrates, direct evidence for the use of magnetic cues, and field-based experiments designed to characterize the biophysical mechanisms of SMA are lacking. Here, we develop a new approach for studies of SMA using triaxial accelerometer and magnetometer bio-loggers attached to semidomesticated red foxes. Results Accelerometer data were recorded from 415 ground-truth events of three behaviors exhibited by an adult red fox. A 5-nearest neighbor classifier was developed for behavioral analysis and performed with an accuracy of 95.7% across all three behaviors. To evaluate the generalizability of the classifier, data from a second fox were tested yielding an accuracy of 66.7%, suggesting the classifier can extract behaviors across multiple foxes. A similar classification approach was used to identify the fox’s magnetic alignment using two 8-way classifiers with differing underlying assumptions to distinguish magnetic headings in eight equally spaced 45° sectors. The magnetic heading classifiers performed with 90.0 and 74.2% accuracy, suggesting a realistic performance range for a classifier based on an independent set of training events equal in size to our sample. Conclusions We report the development of ‘magnetic ethograms’ in which the behavior and magnetic alignment of foxes can be accurately extracted from raw sensor data. These techniques provide the basis for future studies of SMA where direct observation is not necessary and may allow for more sophisticated experimental designs aimed to characterize the sensory mechanisms mediating SMA behavior. Published version false (Extension publication?)

Pancreatic cancer is considered one of the most lethal malignances. It has been observed that the five year survival rate is less than 5%. Early diagnosis, understanding the risk factors and investigation of the molecular pathways with targeted therapy are the keys for efficient treatment. Moreover; there are several local treatments for patients with unresectable pancreatic cancer. There are several combined therapies with chemotherapy and radiotherapy, however; a local therapy approach for many patients with poor performance status are in need. For those patients with good performance status new polychemotherapy regimens are used with success and increased survival improvement. Polychemotherapy has been observed to increase the rate of radical resections in some cases. Second line therapy is used for patients with good performance status and metastatic disease. Oxaliplatin-based regimens are mostly used, however; there are several other drugs that are being developed. Unfortunately, targeted therapy has not presented the expected efficiency. Moreover; immunotherapy; another treatment approach for several cancers types has again failed to present positive results for pancreatic cancer. In the current mini review, we will present information from the diagnosis to molecular pathways and targeted treatment.

The misfit layered Ca3Co4O9 (CCO) is one of the most excellent high temperature oxide thermoelectric (TE) materials because of its environmental friendliness and remarkable thermal stability. In this dissertation, the radio-frequency (rf) magnetron sputtering process was applied to investigate the properties of CCO thin films due to the potential of large-scale production and ease of operation of this technique. It is well known that CaxCoO2 (CCOx12) undergoes a phase transformation to form CCO through reacting with CaO. However, in addition to the stoichiometric deviation of the as-deposited films, rf sputtering produces CCOx12 films instead of CCO. The calcium deficient phase transformation, composition deviation in sputtering and the composition-property relationship of CCO films by rf-sputtering followed with the post-annealing process were investigated. Experiment results showed that the phase transformation during post-annealing proceeded via a calcium self-enrichment process through the decomposition of the CCOx12, thereby resulting in impurities of Co3O4. Negative oxygen ions produced during sputtering resulted in great reduction in thickness and preferential re-sputtering of calcium atoms from the substrate due to the light weight of calcium compared to cobalt. Based on the understanding of the sputtering process for CCO films, additional calcium was added into the targets to compensate for calcium loss during sputtering and optimising the TE performance. In addition, interdiffusion between CCO films and substrates were also investigated because of its critical role in affecting physical properties of thin films, which cause the high temperature application to be challenging. It is the first time that interdiffusion was found to enhanced the TE performance of CCO film on SrTiO3 (111) while having the opposite effect in Al2O3 (0001)substrate. With the STO (001) substrate, CCO grain orientations were found to be significantly affected but without improved TE performance. By controlling the sputtering target compositions and selecting substrates, the optimum TE performance was achieved in pure phase CCO film grown on STO (111) substrate: a low electrical resistivity of ~4 mΩ cm comparable to epitaxial film and a highest reported power factor of ~1.2 mW/mK2 at 973 K so far.

Low noise amplifier is the front end block of radio-frequency receiver system. Its design required various characteristics such as power gain, noise figure, insertion losses and power consumption. In this paper we have proposed a single stage low noise amplifier design with high gain and low noise using inductive source degeneration topology for frequency range of 3 GHz to 7 GHz and also use the active biasing devices. A range of devices like inductors and capacitors are used to achieve 50 Ω input impedance with a low noise factor. The design process is simulated process is using Advance Design System (ADS) and implemented in TSMC 0.18 µm CMOS technology. A single stage low noise amplifier has a measured forward gain 25.4 dB and noise figure 2.2 dB at frequency 5.0 GHz.

Many studies have been performed on exploring the effects of radio-frequency (RF) energy on biological function in vivo. In particular, gene expression results have been inconclusive due, in part, to a lack of a standardized experimental procedure. This research describes a new far field RF exposure system for unrestrained murine models that reduces experimental error. The experimental procedure includes the materials used, the creation of a patch antenna, the uncertainty analysis of the equipment, characterization of the test room, experimental equipment used and setup, power density and specific absorption rate experiment, and discussion. The result of this research is an experimental exposure system to be applied to future biological studies.

Thin film piezoelectric materials offer a number of advantages in microelectromechanical systems (MEMS), due to the large motions that can be generated, often with low hysteresis, the high available energy densities, as well as high sensitivity sensors with wide dynamic ranges, and low power requirements. This paper reviews the literature in this field, with an emphasis on the factors that impact the magnitude of the available piezoelectric response. For non-ferroelectric piezoelectrics such as ZnO and AlN, the importance of film orientation is discussed. The high available electrical resistivity in AlN, its compatibility with CMOS processing, and its high frequency constant make it especially attractive in resonator applications. The higher piezoelectric response available in ferroelectric films enables lower voltage operation of actuators, as well as high sensitivity sensors. Among ferroelectric films, the majority of the MEMS sensors and actuators developed have utilized lead zirconate titanate (PZT) films as the transducer. Randomly oriented PZT films show piezoelectric e(31, f) coefficients of about - 7 C/m(2) at the morphotropic phase boundary. In PZT films, orientation, composition, grain size, defect chemistry, and mechanical boundary conditions all impact the observed piezoelectric coefficients. The highest achievable piezoelectric responses can be observed in {001} oriented rhombohedrally-distorted perovskites. For a variety of such films, e(31,f) coefficients of - 12 to - 27 C/m(2) have been reported.

The main developments taking place in Nuclear Magnetic Resonance Spectroscopy (NMR) of quadrupolar (spin I > 1/2) nuclei with half integer spins in solids, particularly clays and other layered materials, have been reviewed. The advent of Multiple-Quantum (MQ) Magic-Angle Spinning (MAS) NMR spectroscopy has been a step-change development to the studies of quadrupolar nuclei in solids. It is now possible to record high-resolution spectra of important nuclei, such as 11B, 17O, 23Na, 27Al and 69,71Ga, in synthetic and natural clays. Since its introduction in 1995 MQMAS NMR has evolved considerably and, at present, a range of very useful related techniques are available and have been reviewed, as has the current situation with regard to applications to clays and other layered materials.

AIMS: Patients with well-tolerated sustained monomorphic ventricular tachycardia (SMVT) and left ventricular ejection fraction (LVEF) over 30% may benefit from a primary strategy of VT ablation without immediate need for a 'back-up' implantable cardioverter-defibrillator (ICD). METHODS AND RESULTS: One hundred and sixty-six patients with structural heart disease (SHD), LVEF over 30%, and well-tolerated SMVT (no syncope) underwent primary radiofrequency ablation without ICD implantation at eight European centres. There were 139 men (84%) with mean age 62 ± 15 years and mean LVEF of 50 ± 10%. Fifty-five percent had ischaemic heart disease, 19% non-ischaemic cardiomyopathy, and 12% arrhythmogenic right ventricular cardiomyopathy. Three hundred seventy-eight similar patients were implanted with an ICD during the same period and serve as a control group. All-cause mortality was 12% (20 patients) over a mean follow-up of 32 ± 27 months. Eight patients (40%) died from non-cardiovascular causes, 8 (40%) died from non-arrhythmic cardiovascular causes, and 4 (20%) died suddenly (SD) (2.4% of the population). All-cause mortality in the control group was 12%. Twenty-seven patients (16%) had a non-fatal recurrence at a median time of 5 months, while 20 patients (12%) required an ICD, of whom 4 died (20%). CONCLUSION: Patients with well-tolerated SMVT, SHD, and LVEF > 30% undergoing primary VT ablation without a back-up ICD had a very low rate of arrhythmic death and recurrences were generally non-fatal. These data would support a randomized clinical trial comparing this approach with others incorporating implantation of an ICD as a primary strategy.

Purpose. This work aimed to evaluate the feasibility, safety and efficacy of computed Tomography (CT)-guided radio-frequency (RF) treatment for the in situ treatment of osteoid osteoma. Materials and methods. Since March 1997, 17 patients (14 males, 3 females) with 18 osteoid osteomas underwent CT-guided radio-frequency thermal ablation. Lesions were located in the femur ( n =13), tibia ( n =3), radius ( n =1) and ulna ( n =1). All patients had presumptive diagnosis of osteoid osteoma on the basis of clinical and radiographic findings. The duration of pain before treatment ranged between 6 and 18 months (mean: 9 months). Of the 18 procedures, 15 were performed percutaneously while 3 others were performed after surgical exposure of the bone. No surgical treatments were performed before RF ablation. A 17-gauge electrode needle with 2-cm exposed tip was introduced into the nidus through an 11-gauge biopsy set. Results. All the procedures were technically successful. Of 17 patients, 14 were completely free of pain within 2 days post-treatment. In two patients, complete relief from pain was achieved after a second RF ablation. In another case, no clinical response was observed; the patient refused to repeat treatment and underwent surgery. Two cases had superficially dermal burns with skin and soft tissue necrosis.

We study dipolar relaxation in both ultra-cold thermal and Bose-condensed chromium atom gases. We show three different ways to control dipolar relaxation, making use of either a static magnetic field, an oscillatory magnetic field, or an optical lattice to reduce the dimensionality of the gas from 3D to 2D. Although dipolar relaxation generally increases as a function of a static magnetic field intensity, we find a range of non-zero magnetic field intensities where dipolar relaxation is strongly reduced. We use this resonant reduction to accurately determine the S=6 scattering length of chromium atoms: $a_6 = 103 \pm 4 a_0$. We compare this new measurement to another new determination of $a_6$, which we perform by analysing the precise spectroscopy of a Feshbach resonance in d-wave collisions, yielding $a_6 = 102.5 \pm 0.4 a_0$. These two measurements provide by far the most precise determination of $a_6$ to date. We then show that, although dipolar interactions are long-range interactions, dipolar relaxation only involves the incoming partial wave $l=0$ for large enough magnetic field intensities, which has interesting consequences on the stability of dipolar Fermi gases. We then study ultra-cold chromium gases in a 1D optical lattice resulting in a collection of independent 2D gases. We show that dipolar relaxation is modified when the atoms collide in reduced dimensionality at low magnetic field intensities, and that the corresponding dipolar relaxation rate parameter is reduced by a factor up to 7 compared to the 3D case. Finally, we study dipolar relaxation in presence of radio-frequency (rf) oscillating magnetic fields, and we show that both the output channel energy and the transition amplitude can be controlled by means of rf frequency and Rabi frequency., Comment: 25 pages, 17 figures

[EN] Radio-frequency thermokeratoplasty (RF-TKP) is a technique used to reshape the cornea curvature by means of thermal lesions using radio-frequency currents. This curvature change allows refractive disorders such as hyperopia to be corrected. A new electrode with ring geometry is proposed for RF-TKP. It was designed to create a single thermal lesion with a full-circle shape. Finite element models were developed, and the temperature distributions in the cornea were analysed for different ring electrode characteristics. The computer results indicated that the maximum temperature in the cornea was located in the vicinity of the ring electrode outer perimeter, and that the lesions had a semi-torus shape. The results also indicated that the electrode thickness, electrode radius and electrode thermal conductivity had a significant influence on the temperature distributions. In addition, in vitro experiments were performed on rabbit eyes. At 5 IN power the lesions were fully circular. Some lesions showed non-uniform characteristics along their circular path. Lesion depth depended on heating duration (60% of corneal thickness for 20s, and 30% for 10s). The results suggest that the critical shrinkage temperature (55-63degreesC) was reached at the central stroma and along the entire circular path in all the cases.

Cataloged from PDF version of article. In this work, we present a method to probe molecular interactions on single-walled carbon nanotube (SWNT) surfaces using a surface plasmon sensor. SWNT networks were synthesized by chemical vapor deposition and transfer-printed on gold surfaces. We studied the excitation of surface plasmon-polaritons on nanotube coated gold surfaces with sub-monolayer, monolayer, and multilayer surface coverage. Integrating the fabricated sensor with a microfluidic device, we were able to obtain binding dynamics of a bovine serum albumin (BSA) protein on SWNT networks with various tube densities. The results reveal the kinetic parameters for nonspecific binding of BSA on SWNT coated surfaces having various tube densities. (C) 2012 American Institute of Physics.

This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56MHz frequency, 0.1–1 mbar pressures and 2–30W coupled powers. Experiments performed on two similar (not twin) setups, existing in the LATMOS and the GREMI laboratories, include electrical and optical emission spectroscopy (OES) measurements. Electrical measurements give the rf-applied and the direct-current-self-bias voltages, the effective power coupled to the plasma and the average electron density. OES diagnostics measure the intensities of radiative transitions with the nitrogen second-positive and first-negative systems, and with the 811.5 nm atomic line of argon (present as an actinometer). Simulations use a hybrid code that couples a two-dimensional time-dependent fluid module, describing the dynamics of the charged particles (electrons and positive ions N+2 and N+4 ), and a zero-dimensional kinetic module, describing the production and destruction of nitrogen (atomic and molecular) neutral species. The coupling between these modules adopts the local mean energy approximation to define space–time-dependent electron parameters for the fluid module and to work out space–time-averaged rates for the kinetic module. The model gives general good predictions for the self-bias voltage and for the intensities of radiative transitions (both average and spatially resolved), underestimating the electron density by a factor of 3–4., This work is supported by a PICS Cooperation Program, financed by the Portuguese Foundation for Science and Technology (FCT) and by the Centre National de la Recherche Scientifique (CNRS). The calculations were performed on SeARCH (Services & Advanced Computing with HTC/HPC) funded by FEDER through the COMPETE program and by the Portuguese FCT under contract CONC-REEQ/443/EEI/2005. Et Es-sebbar thanks the ANR programme (ANR-09-JCJC-0038 contract) for his Post-Doctoral grant.

We study the effect of strong radio-frequency (rf) fields on a chromium Bose-Einstein condensate (BEC), in a regime where the rf frequency is much larger than the Larmor frequency. We use the modification of the Land\'{e} factor by the rf field to bring all Zeeman states to degeneracy, despite the presence of a static magnetic field of up to 100 mG. This is demonstrated by analyzing the trajectories of the atoms under the influence of dressed magnetic potentials in the strong field regime. We investigate the problem of adiabaticity of the rf dressing process, and relate it to how close the dressed states are to degeneracy. Finally, we measure the lifetime of the rf dressed BECs, and identify a new rf-assisted two-body loss process induced by dipole-dipole interactions., Comment: 4 pages, 4 figures

SPIDER is the full scale prototype for the ITER Heating Neutral Beam source, hosted at the Neutral Beam Test Facility in Padova, Italy. The behavior of the beam must be thoroughly investigated to bring the machine's performance in line with ITER's requirements. In particular, ripples in the beam can affect its divergence. Measuring the AC component of the beam current can therefore help to understand the impact that the oscillations caused by the source power supplies or RF generators have on the beam optics.To minimize the occurrence of electrical discharges, SPIDER was recently operated with a mask designed to close a large number of extraction apertures. As a consequence, the space between each beamlet was substantially increased, allowing for the installation of the Beamlet Current Monitor (BCM) which enables a non-invasive direct measurement of the DC and AC components of the currents of 5 individual beamlets.A first assessment of the beamlet currents' AC components (up to 10 MHz) was performed during SPIDER's first campaign with cesium evaporation. Recurring oscillations were identified in various frequency ranges, with amplitudes reaching up to similar to 7% of the beamlet current DC value. When possible, the ripples were correlated to oscillations due to the RF oscillators and the beatings caused by their mutual coupling, or to SPIDER's power supply systems.

The paper presents a study of electromagnetic field processing of semi-manufactured wood in RF structures at 13.56 MHz. The staggeredthrough-field applicator is used and the advantages ofthis applicator for the semi-manufactured wood processing are highlighted. The benefits over conventional heating and drying methods of RF heating are discussed, and also the advantages overmicrowave heating for this specific application are mentioned. The experimental results, assisted with numerical modelling allow the establishment of optimum parameters for RF wood drying.