Design of a high-dynamic-range prototype readout system for VLAST calorimeter

In the future, the Very Large Area gamma-ray Space Telescope is expected to observe high-energy electrons and gamma rays in the MeV to TeV range with unprecedented acceptance. As part of the detector suite, a high-energy imaging calorimeter(HEIC) is currently being developed as a homogeneous calorimeter that utilizes long bismuth germanate(BGO) scintillation crystals as both absorbers and detectors. To accurately measure the energy deposition in the BGO bar of HEIC, a highdynamic-range readout method using a silicon photomultiplier(SiPM) and multiphotodiode(PD) with different active areas has been proposed. A prototype readout system that adopts multichannel charge measurement ASICs was also developed to read out the combined system of SiPMs and PDs. Preliminary tests confirmed the feasibility of the readout scheme, which is expected to have a dynamic range close to 10~6.

Comparison of performance between rescaled range analysis and rescaled variance analysis in detecting abrupt dynamic change

In the present paper, a comparison of the performance between moving cutting data-rescaled range analysis （MC- R/S） and moving cutting data-rescaled variance analysis （MC-V/S） is made. The results clearly indicate that the operating efficiency of the MC-R/S algorithm is higher than that of the MC-V/S algorithm. In our numerical test, the computer time consumed by MC-V/S is approximately 25 times that by MC-R/S for an identical window size in artificial data. Except for the difference in operating efficiency, there are no significant differences in performance between MC-R/S and MC-V/S for the abrupt dynamic change detection. Mc-R/s and MC-V/S both display some degree of anti-noise ability. However, it is important to consider the influences of strong noise on the detection results of MC-R/S and MC-V/S in practical application

Modulation of neuronal dynamic range using two different adaptation mechanisms

The capability of neurons to discriminate between intensity of external stimulus is measured by its dynamic range.A larger dynamic range indicates a greater probability of neuronal survival.In this study,the potential roles of adaptation mechanisms（ion currents） in modulating neuronal dynamic range were numerically investigated.Based on the adaptive exponential integrate-and-fire model,which includes two different adaptation mechanisms,i.e.subthreshold and suprathreshold（spike-triggered） adaptation,our results reveal that the two adaptation mechanisms exhibit rather different roles in regulating neuronal dynamic range.Specifically,subthreshold adaptation acts as a negative factor that observably decreases the neuronal dynamic range,while suprathreshold adaptation has little influence on the neuronal dynamic range.Moreover,when stochastic noise was introduced into the adaptation mechanisms,the dynamic range was apparently enhanced,regardless of what state the neuron was in,e.g.adaptive or non-adaptive.Our model results suggested that the neuronal dynamic range can be differentially modulated by different adaptation mechanisms.Additionally,noise was a non-ignorable factor,which could effectively modulate the neuronal dynamic range.

Dynamic range and linearity improvement for zero-field single-beam atomic magnetometer

Zero-field single-beam atomic magnetometers with transverse parametric modulation for ultra-weak magnetic field detection have attracted widespread attention recently.In this study,we present a comprehensive response model and propose a modification method of conventional first harmonic response by introducing the second harmonic correction.The proposed modification method gives improvement in dynamic range and reduction of linearity error.Additionally,our modification method shows suppression of response instability caused by optical intensity and frequency fluctuations.An atomic magnetometer with single-beam configuration is built to compare the performance between our proposed method and the conventional method.The results indicate that our method’s magnetic field response signal achieves a 5-fold expansion of dynamic range from 2 nT to 10 nT,with the linearity error decreased from 5%to 1%.Under the fluctuations of 5%for optical intensity and±15 GHz detuning of frequency,the proposed modification method maintains intensityrelated instability less than 1%and frequency-related instability less than 8%while the conventional method suffers 15%and 38%,respectively.Our method is promising for future high-sensitive and long-term stable optically pumped atomic sensors.

Extraordinary tunable dynamic range of electrochemical aptasensor for accurate detection of ochratoxin A in food samples

We report the design of a sensitive,electrochemical aptasensor for detection of ochratoxin A(OTA)with an extraordinary tunable dynamic sensing range.This electrochemical aptasensor is constructed based on the target induced aptamer-folding detection mechanism and the recognition between OTA and its aptamers results in the conformational change of the aptamer probe and thus signal changes for measurement.The dynamic sensing range of the electrochemical aptasensor is successfully tuned by introduction of free assistant aptamer probes in the sensing system.Our electrochemical aptasensor shows an extraordinary dynamic sensing range of 11-order magnitude of OTA concentration from 10^−8 to 10^2 ng/g.Of great significance,the signal response in all OTA concentration ranges is at the same current scale,demonstrating that our sensing protocol in this research could be applied for accurate detections of OTA in a broad range without using any complicated treatment of signal amplification.Finally,OTA spiked red wine and maize samples in different dynamic sensing ranges are determined with the electrochemical aptasensor under optimized sensing conditions.This tuning strategy of dynamic sensing range may offer a promising platform for electrochemical aptasensor optimizations in practical applications.

Effects of refractory period on dynamical range in excitable networks

Effects of refractory period on the dynamical range in excitable networks are studied by computer simulations and theoretical analysis. The first effect is that the maximum or peak of the dynamical range appears when the largest eigenvalue of adjacent matrix is larger than one. We present a modification of the theory of the critical point by considering the correlation between excited nodes and their neighbors, which is brought by the refractory period. Our analysis provides the interpretation for the shift of the peak of the dynamical range. The effect is negligible when the average degree of the network is large. The second effect is that the dynamical range increases as the length of refractory period increases, and it is independent of the average degree. We present the mechanism of the second effect. As the refractory period increases,the saturated response decreases. This makes the bottom boundary of the dynamical range smaller and the dynamical range extend.

Icosahedral medium-range order formed in Mg_(70)Zn_(30) metallic glass: a larger-scale molecular dynamics simulation

A larger-scale Mg70Zn30 alloy system including 100000 atoms has been simulated by using the molecular dynamics method to investigate the icosahedral medium-range order （IMRO） formed in the MgToZn30 metallic glass. It is found that the simulated pair distribution function of Mg70Zn30 metallic glass is in good agreement with the experimental results. The glass transition temperature Tg is near 450 K under the cooling rate of 1×10^12 K/s. The icosahedral local structures play a critical role in the formation of metallic glass, and they are the dominant local configurations in the Mg70Zn30 metallic glass. The IMRO in the Mg70Zn30 metallic glass is characterized by certain types of extended icosahedral clusters combined by intercross-sharing atoms in the form of chains or dendrites. The size distributions of these IMRO clusters present a magic number sequence of 19, 23, 25, 27, 29, 31, 33, 35, 37, 39,..., and the magic clusters can be classified into three types according to their compactness. The IMRO clusters grow rapidly in a low-dimensional way with cooling, but this growth is limited near Tg.

Research for the Dynamic Range and Its Extension of Digital Intermediate Frequency Receiver

For the optimization of dynamic range and bandwidth of digital intermediate frequency receiver(DIFR), main factors affecting them and their relationships are studied. Firstly, the DIFR sensitivity, bandwidth, noise factor of radio frequency (RF) analog front-end (RFAF), and processing gain of intermediate frequency(IF) sampling are analyzed. Secondly, the constraint relationship of the noise factor of RFAF, the signal-to-noise ratio of ADC and the dynamic range of DIFR are studied. The relationship between the dynamic range and the RFAF gain, and that of the extended dynamic range and the RF AGC(automatic gain control) step are educed and simulated. These results can be used as theory foundations and design references for the implementation and optimization of the large dynamic range and wideband DIFR.

Distortion-Free Data Embedding Scheme for High Dynamic Range Images

Distortion-free data embedding is a technique which can assure that not only the secret data is correctly extracted but also the cover media is recovered without any distortion after secret data is extracted completely. Because of these advantages, this technique attracts the attention of many researchers. In this paper, a new distortion-free data embedding scheme for high dynamic range （HDR） images is proposed. By depending on Cartesian product, this scheme can obtain higher embedding capacity while maintaining the exactly identical cover image and stego image when using the tone mapping algorithms. In experimental results, the proposed scheme is superior to Yu et aL＇s scheme in regard to the embedding rate——an average embedding rate of 0.1355 bpp compared with Yn et aL＇s scheme （0.1270 bpp）.

Analysis of Wide-Bandgap Material OPFET UV Detectors for High Dynamic Range Imaging and Communication Applications

The ultraviolet (UV) photoresponses of Wurtzite GaN, ZnO, and 6H-SiC-based Optical Field Effect Transistor (OPFET) detectors are estimated with an in-depth analysis of the same considering the generalized model and the front-illuminated model for high resolution imaging and UV communication applications. The gate materials considered for the proposed study are gold (Au) and Indium-Tin-Oxide (ITO) for GaN, Au for SiC, and Au and silver dioxide (AgO2) for ZnO. The results indicate significant improvement in the Linear Dynamic Range (LDR) over the previously investigated GaN OPFET (buried-gate, front-illuminated and generalized) models with Au gate. The generalized model has superior dynamic range than the front-illuminated model. In terms of responsivity, all the models including buried-gate OPFET exhibit high and comparable photoresponses. Buried-gate devices on the whole, exhibit faster response than the surface gate models except in the AgO2-ZnO generalized OPFET model wherein the switching time is the lowest. The generalized model enables faster switching than the front-illuminated model. The switching times in all the cases are of the order of nanoseconds to picoseconds. The SiC generalized OPFET model shows the highest 3-dB bandwidths of 11.88 GHz, 36.2 GHz, and 364 GHz, and modest unity-gain cut-off frequencies of 4.62 GHz, 8.71 GHz, and 5.71 GHz at the optical power densities of 0.575 μW/cm2, 0.575 mW/cm2, and 0.575 W/cm2 respectively. These are in overall, the highest detection-cum-amplifi-cation bandwidths among all the investigated devices. The same device exhibits the highest LDR of 73.3 dB. The device performance is superior to most of the other existing detectors along with comparable LDR, thus, emerging as a high performance photodetector for imaging and communication applications. All the detectors show considerably high detectivities owing to the high responsivity values. The results have been analyzed by the photovoltaic and the photoconductive effects, and the series resistance effects and will aid in conducting further research. The results are in line with the experiments and the commercially available software simulations. The devices will greatly contribute towards single photon counting, high resolution imaging, and UV communication applications.

A 0.18μm CMOS GAIN-SWITCHED LNA AND MIXER WITH LARGE DYNAMIC RANGE

A 2.4GHz 0.18μm CMOS gain-switched single-end Low Noise Amplifier(LNA) and a passive mixer with no external balun for near-zero-IF(Intermediate Frequency)/RF(Radio Frequency) applications are described.The LNA,fabricated in the 0.18μm 1P6M CMOS technology,adopts a gain-switched technique to increase the linearity and enlarge the dynamic range.The mixer is an IQ-based passive topology.Measurements of the CMOS chip are performed on the FR-4 PCB and the input is matched to 50Ω.Combining LNA and mixer,the front-end measured performances in high gain state are:-15dB of S11,18.5dB of voltage gain,4.6dB of noise figure,-15dBm of ⅡP3,-85dBm to -10dBm dynamic range.The full circuit drains 6mA from a 1.8V supply.

Improvement of High Dynamic Range Capacitive Displacement Sensor by a Globalm Planarization

This study presents an improvement of high dynamic range contact-type capacitive displacement sensor by applying planarization. The sensor is called the contact-type linear encoder-like capacitive displacement sensor (CLECDiS), is a nano-meter-resolution sensor with a wide dynamic range. However, height differences due to patterned electrodes may cause a variety of problems or performance degradation. In devices of two glass wafer surfaces with patterned structures assembled face-to-face and in sliding contact, the heights of the patterns crucially affect their performance and practicality, so it should be planarized for reducing the problem. A number of techniques for planarizing glass wafer surfaces with patterned chrome electrodes were evaluated and the following three were selected as adequate: lift-off, etch-back, and chemical mechanical polishing (CMP). The fabricated samples showed that CMP provided the best planarization. CMP was successfully employed to produce CLECDiS with improved signal reliability due to reduced collisions between electrodes.

Multi-exposure fusion for high dynamic range scene

Due to the existing limited dynamic range a camera cannot reveal all the details in a high-dynamic range scene. In order to solve this problem,this paper presents a multi-exposure fusion method for getting high quality images in high dynamic range scene. First,a set of multi-exposure images is obtained by multiple exposures in a same scene and their brightness condition is analyzed. Then,multi-exposure images under the same scene are decomposed using dual-tree complex wavelet transform( DT-CWT),and their low and high frequency components are obtained. Weight maps according to the brightness condition are assigned to the low components for fusion. Maximizing the region Sum Modified-Laplacian( SML) is adopted for high-frequency components fusing. Finally,the fused image is acquired by subjecting the low and high frequency coefficients to inverse DT-CWT.Experimental results show that the proposed approach generates high quality results with uniform distributed brightness and rich details. The proposed method is efficient and robust in varies scenes.

ANALYSIS OF STRUCTURAL STYLES OF THE BASIN-RANGE SYSTEMS IN THE CENTRAL CHINA OROGENIC CHAIN OF YANGTZE VALLEY AND THE DYNAMIC MECHANISM

Basin and orogenic belt belong to the same tectonic system which has close connections in spatial distribution and dynamic mechanism.Structural styles analysis of basin－ range system， not only may rebuild basin－ range coupling process and landscape evolution of orogenic belt and its adjacent basin， but also become the foundation in exploring how orogenesis controls landform,climate,resources,energy and environment etc.In the light of geodynamic mechanism,three main types of basin－ range system may be classified,namely,stretch,compression and strike－ slip.In combination with their geotectonic settings and plate movement phases, a comprehensive classification scheme may be educed for structural styles of basin－ range system.Natural disasters and geo－ ecological environment in the Yangtze Valley have been restricted and impressed by crustal movement and Qinling－ Dabie etc.orogenesis since the Mesozoic and Cenozoic.In terms of collocating relation and contacting basin prototype and orogenic belt around the basin for cause of formation, typical structural styles of basin－ range system on the central orogenic chain within the Yangtze Valley consist of coupling Tongbo－ Dabie orogenic belt and Jianghan－ Dongtin fault basin on the northern margin of the central Yangtze landmass， and coupling Qinling－ Daba mountain margin thrust－ faulted orogenic belt and Sichuan foreland basin on the northern margin of upper－ Yangtze landmass.The paper analyzes evolutionary features of two typical structural styles of basin－ range system during syn－ orogenic, late－ orogenic and post－ orogenic stages,and probes into their dynamic mechanism.It is emphasized that,in different stages of basin－ range system of different properties and basin－ mountain transformation process,different structural styles may be formed;and different associations of structural styles can form different types of natural disasters complex and eco－ environment systems.

Method of Dynamic VaR and CVaR Risk Measures Forecasting for Long Range Dependent Time Series on the Base of the Heteroscedastic Model

The paper proposes a new method of dynamic VaR and CVaR risk measures forecasting. The method is designed for obtaining the forecast estimates of risk measures for volatile time series with long range dependence. The method is based on the heteroskedastic time series model. The FIGARCH model is used for volatility modeling and forecasting. The model is reduced to the AR model of infinite order. The reduced system of Yule-Walker equations is solved to find the autoregression coefficients. The regression equation for the autocorrelation function based on the definition of a long-range dependence is used to get the autocorrelation estimates. An optimization procedure is proposed to specify the estimates of autocorrelation coefficients. The procedure for obtaining of the forecast values of dynamic risk measures VaR and CVaR is formalized as a multi-step algorithm. The algorithm includes the following steps: autoregression forecasting, innovation highlighting, obtaining of the assessments for static risk measures for residuals of the model, forming of the final forecast using the proposed formulas, quality analysis of the results. The proposed method is applied to the time series of the index of the Tokyo stock exchange. The quality analysis using various tests is conducted and confirmed the high quality of the obtained estimates.

Fast Scheme for Projective Geometric Correction and Edge Blending Based on High Dynamic Range Images

With the development of graphic processing unit(GPU)power,it is now possible to implement geometric correction and edge blending functions on a single computer.However,the processing resources consumed by the geometric correction and edge blending phases still burden the system and slow down the main application considerably.A new platform independent scheme is proposed,minimizing the negative influence on performance.In this scheme,parameters for geometric correction and edge blending are firstly defined in an interactive way and recorded as a 32-bit high dynamic range(HDR) image,which is then used by high level shading language(HLSL) codes embedded in the main application as a lookup table,greatly reducing the computational complexity and enhancing flexibility.

A Parallel Amplifier Structure for Increasing Dynamic Range of EW Receivers

In Electronic Warfare （EW） receivers, the desired Dynamic Range （DR） often far exceeds the dynamic range attainable with available Analog-to-Digital Converter （ADC） technology. ADC is the key bottleneck in achieving the needed dynamic range. In this paper, an approach for improving the effective DR by utiliTing multiple amplifiers is presented. The amplifiers, arranged in parallel channels with different gains, can increase the dynamic range greatly.

Dynamic Free-Spectral-Range Measurement for Fiber Resonator Based on Digital-Heterodyne Optical Phase-Locked Loop

We propose a novel scheme, based on digital-heterodyne optical phase-locked loop with whole-fiber circuit, to dynamically measure the free-spectral-range of a fiber resonator. The optical phase-locked loop is established with a differential frequency-modulation module consists of a pair of acousto-optic modulators. The resonance-tracking loop is derived with the Pound-Drever-Hall technique for locking the heterodyne frequency of the OPLL on the frequency difference between adjacent resonance modes. A stable locking accuracy of about 7 × 10?9 and a dynamic locking accuracy of about 5 × 10?8 are achieved with the FSR of 8.155 MHz, indicating a bias stability of the resonator fiber optic gyro of about 0.1?/h with 10 Hz bandwidth. In addition, the thermal drift coefficient of the FSR is measured as 0.1 Hz/?C. This shows remarkable potential for realizing advanced optical measurement systems, such as the resonant fiber optic gyro, and so on.

Effects of Sevoflurane on the discharges of wide dynamic range neurons in spinally transected rats

Objective: To study the effects of clinical concentration of sevoflurane on activity of wide dynamic range neurons. Methods: Eight Spraque-Dawley rats(male) were selected. Their spinal cords were exposed and transected at T 9-10 level. The rate of firings of single neurons in the dorsal horn in response to electrical stimulation of skin was recorded with microelectrodes. The early and late discharges were observed when rats inhaled 0.5%, 1.0%, 1.5%, and 2.0% sevoflurane. Results: Sevoflurane suppressed the early and late discharges at the concentration of 0.5%, 1.0%, 1.5%, and 2.0%. Compared with early discharges, the extent of inhibition of late discharges was wider at the concentration of 1%, 1.5%, and 2.0% of sevoflurane. Conclusion: It is indicated that sevoflurane could suppress the transmission of nociceptive and non-nociceptive stimulation at dorsal horn. The suppression on nociceptive imput is stronger than that on non-nociceptive imput when the concentration of sevoflurane is more than 1%.