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The presence of various combinations of adjacent colors within polymorphic species’ color pattern could have a major impact on mate choice. We studied the role of pattern geometry in predicting mate choice in guppies using boundary strength analysis (BSA). BSA estimates the visual contrast intensity between two adjacent color patches (ΔS) weighted by the lengths of the boundaries between these adjacent color patches. We measured both the chromatic (hue and saturation) and achromatic (luminance) ΔS for each pair of adjacent patches. For each male’s color pattern, we measured BSA as both mean (mΔS) and coefficient of variation (cvΔS) of all ΔS weighted by their corresponding boundary lengths. We also determined if specific color patch boundaries had an impact on female preferences and whether these predicted overall male contrast (mΔS). We found that males with a higher mΔS were more attractive to females and that six boundaries containing either fuzzy black or black as one of the pair colors significantly affected female preferences, indicating that 1) females favored highly conspicuous males and 2) melanin-based patches could be used as a signal amplifier, not only for orange but for other colors.

A single-atom metal doped on carbonaceous nanomaterials has attracted increasing attention due to its potential applications as high-performance catalysts. However, few studies focus on the applications of such nanomaterials as nanotheranostics for simultaneous bioimaging and cancer therapy. Herein, it is pioneeringly demonstrated that the single-atom Gd anchored onto graphene quantum dots (SAGd-GQDs), with dendrite-like morphology, was successfully prepared. More importantly, the as-fabricated SAGd-GQDs exhibits a robustly enhanced longitudinal relaxivity (

An electrochemiluminescence (ECL) sensor was constructed with graphitic carbon nitride nanosheets (g-C3N4 NSs) as the luminophor and multi-walled carbon nanotubes (MWCNT) as signal amplifier. It wa...

Consideration is given to the research status and prospects for development of plasma relativistic microwave electronics as a basis for plasma masers. Possible applications are determined for plasma masers as high-power sources of microwave pulses. Design features of masers and their radiation characteristics are considered with a view to the type of device: self-oscillator, external signal amplifier, or noise amplifier.

This work deals with the design of a portable device for measuring and monitoring corrosion variables. The measured variables are the electrochemical potential (EP) and electrochemical current (EC). Using these signals the localization index (LI) and the corrosion rate (CR) can be estimated. Since electrochemical potential (EP) and electrochemical current (EC) are weak signals, an electronic circuit was designed and developed for measuring these two variables. The electronic circuit includes a signal amplifier, a physical filter, and an Analog to Digital Converter (ADC). To estimate the IL and CR the statistical method and Neural Network method were used and compared. The device advantages are its low-cost of construction, its portability and the possibility to analyze the corrosion variables in different materials. Experimental tests carried out using 6061-T6 aluminum shown the effectiveness of the proposed device and methods and the versatility of the portable device.

The work offers the improvement of oxygen monitoring instrument of a gas torch with the use of a simple tool base which does not demand a high level of qualification of operator. An electronic block of pyrometer was developed and investigated. The pyrometer is designed to measure flow of solid particles in a high-temperature two-phase flow. The operating range of spectrum is 0,5•10-6 ... 1,1•10-6 m. The justification of choice of radiation receiver was carried out and calculation of electrical signal at radiation receiver was performed. The radiation receiver is a photodiode FD-25K, which is selective, of little inertia, has small dimensions, operates at a small voltage of power source. The spectral range measuring flux of radiation flame is limited by spectral sensitivity of radiation receiver (wavelength 0,5•10-6 ... 1,1•10-6 m). The signal amplifier is designed. The signal amplifier is a converter of an electric current of a photodiode into a voltage. The photodiode is switched on in photovoltaic mode (without bias voltage), which ensures the absence of dark current. The calculation and experimental values of the parameters of the electronic unit of the measuring device are presented in the article.

We report a fluorescence polarization (FP) platform for human immunodeficiency virus (HIV) DNA detection based on T7exonuclease-assisted target recycling amplification with graphene oxide (GO) acting as a FP signal amplifier. In the sensing method, the presence of the target DNA leads to target recycling with the assistance of T7exonuclease, furthermore, the amplification products are absorbed onto the surface of GO, so the all FP values are enhanced by GO. More importantly, this FP sensor exhibits high detection sensitivity; under optimal conditions, the change in FP is linear with the concentration of the target DNA within a concentration range of 50-2000 pmol/L, and the detection limit of this method is as low as 38.6 pmol/L. This FP sensor also exhibits high selectivity, even single-base mismatched DNA can be effectively discriminated from complementary target DNA. Above all, the proposed FP sensor may serve as a general platform for the sensitive assay of disease-related genes.

In this paper, a simplified technique is proposed which enables the user to nullify offset whenever power is switched on of the circuit and also based on the requirement of the user. In this method strain sensor is the part of the resistive bridge which is used as Quarter Bridge. The voltage excitation to the bridge is provided by a voltage reference. The output of the bridge reaches precision sensor signal amplifier through over-voltage protection circuit. Dynamic range and bridge offset adjustment both can be achieved in the circuit as per requirement. High precision Analog to Digital Converter digitizes data. The output is then captured on the monitoring computer to verify the results.

The paper presents a methodology for determination of harmonic iron losses in laminated iron cores under sinusoidal and non-sinusoidal excitation. The measurements are performed by using a convenient Epstein device supplied by a signal amplifier and are registered in a PC by using an appropriate data acquisition system. Eddy currents in iron laminations are modeled by finite element techniques while leakage field, respective inductances and losses are compared to measured ones.

Early diagnostics of diseases performed with minimal money and time consumption has become achievable due to recent advances in development of biosensors. These devices use biorecognition elements for selective interaction with an analyte and signal readout is obtained via different types of transducers. Operational characteristics of biosensors have been reported to improve substantially, when a diverse range of nanomaterials was employed. This review presents construction of electrochemical biosensors based on graphene, atomically thin 2D carbon crystals, which is currently intensively studied nanomaterial. The most attractive directions of graphene applications in biosensor preparation are discussed here including novel detection and amplification schemes exploiting graphene’s unique electrochemical, physical and chemical properties. The future of graphene-based biosensors is most likely bright, but there is still a lot of work to do to fulfill high expectations. Slovak scientific grant agency VEGA 2/0162/14 and from the Slovak research and development agency APVV 0282-11 is acknowledged. The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement No. 311532 and this work has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 317420. This work was funded by the National Priorities Research Program (Qatar National Research Fund), NPRP 6-381-1-078.

In this Letter we demonstrate the operation of an analog small-signal amplifier based on single-layer MoS2, a semiconducting analogue of graphene. Our device consists of two transistors integrated on the same piece of single-layer MoS2. The high intrinsic band gap of 1.8 eV allows MoS2-based amplifiers to operate with a room temperature gain of 4. The amplifier operation is demonstrated for the frequencies of input signal up to 2 kHz preserving the gain higher than 1. Our work shows that MoS2 can effectively amplify signals and that it could be used for advanced analog circuits based on two-dimensional materials., Comment: Submitted version of the manuscript

An active-matrix a-Si thin-film transistor liquid-crystal display (TFT-LCD) with 720 × 480 pixel resolution has been developed as a projector, enabling the display of sharp images on extended definition TV (EDTV) and computer monitors that support a full range of multimedia applications. To enhance picture quality, an LC transmission-voltage (T-V) correction circuit has been developed that incorporates a nonlinear video signal amplifier based on curve-fitting. To extend the panel's capabilities so that it can project images on computer display monitors, a ew drive circuits have been developed that incorporate 8-MHz analogue driver LSIs and sample-and-hold circuits.

The purpose of the current study was to develop a magnetic resonance (MR)-compatible photoplethysmograph (PPG) system which could measure the raw PPG signal during MR image acquisition. The system consisted of an optic sensor which measured the optic signal, an optic cable which transmitted a near-infrared optic signal, a signal amplifier, and a filter for noise removal. To minimize interactive noise, only the optic cable and the optic sensor module were located inside the MR room; the signal amplifier and filter were located outside the MR room. The experiment verified that a reliable PPG signal can be obtained without deteriorating the MR image. Especially, it was possible to get a reliable PPG signal while acquiring MR images with EPI method which has been used for functional magnetic resonance imaging (fMRI) study. This system can simultaneously measure the response of the central nervous system using fMRI and that of the peripheral nervous system using the PPG.

Reference EPFL-ARTICLE-185377doi:10.1063/1.4791668View record in Web of Science Record created on 2013-03-28, modified on 2017-05-10

This chapter describes a simple, straightforward approach to the design of low power RF amplifiers. The three basic ingredients of a design are the selection of a bias point, use of scattering parameters, and noise parameters to complete a specific circuit procedure. Choosing a bias point is less difficult than designing a suitable bias network. The bias point must be at a sufficiently high current (and voltage) level to prevent the input signal from swinging the collector current out of the linear region of operation. Impedance matching, gain, input and output VSWR, and stability can be expressed by mathematical equations involving scattering parameters (S-parameters). The S -parameters are basically a means for characterizing n-port networks using the concept of traveling waves. The S- parameters help in calculating device stability by determining a term called the Rollett Stability Factor K . The lowest noise figure is achieved by creating the proper source impedance to the transistor that results in minimum noise. Suitable performance over a band of frequencies can be accomplished by presenting to the transistor source and load impedances that will achieve proper overall circuit results as frequency varies.

This paper describes the optimization of a lateral magnetotransistor (LMT), combined with a signal amplifier. The base width, the position of the base contact and the substrate doping level are important design criteria. An integrated circuit comprising a dual-collector lateral magnetotransistor and a differential amplifier yields a sensitivity of 10 V/T.

Current interest in efficient blue solid-state laser sources has led to research aimed at converting laser radiation in the 1.3μ region to the blue (4300–4600A). In this paper we describe laser operation on the \(^4{{\text{F}}_{3/2}}{ - ^4}{{\text{I}}_{13/2}}\) laser transition in Nd:YLF including the prominent π and σ polarized lines, 1.321μ and 1.313μ, and continuous tuning over the weaker band between 1.362 and 1.37 microns. Small signal amplifier gain measurements of the various transitions between these multiplets are presented in addition to a Q-switched oscillator, emitting 90mJ at 1.3665μ and an oscillator amplifier chain emitting 0.5J at 1.313 microns.

An investigation was made of the use of a two-pass telescopic neodymium-glass amplifier in combination with a Brillouin mirror in high-gain wavefront-reversal systems. Small-signal gain of 107 was achieved for a single pulse of SO nsec duration and no self-focusing filaments were observed in the output stage when the energy was up to 100 J.