This paper represents a novel digital readout for infrared focal plane arrays with 2.33 Ge− charge handling capacity while achieving quantization noise of 161 e−. Pixel level A/D conversion has been realized by pulse frequency modulation (PFM) technique supported with a novel method utilizing extended integration that eliminates the requirement for an additional column ADC. Digital pixel operates with two phases; the first phase is as ordinary PFM in charge domain and the second phase is in time domain, allowing the fine quantization and low quantization noise. A 32 × 32 prototype has been manufactured and tested. Measured peak SNR at half well fill is 71 dB with significant SNR improvement for low illuminated pixels due to extremely low quantization noise. 32 × 32 ROIC dissipates only 1.1 mW and the figure of merit for power dissipation is measured to be 465 fJ/LSB, compared to 930 fJ/LSB and 1470 fJ/LSB of the state of the art. 相似文献
The perylene(C20H12) layer effect on the electrical and dielectric properties of Al/p-Si(MS) and Al/perylene/p-Si(MPS) diodes have been investigated and compared in the frequency range of 0.7 kHz–2 MHz. Experimental results show that C–V characteristics give an anomalous peak for two structures at low frequencies due to interface states(Nss) and series resistance(Rs). The increases in C and G/ω at low frequencies confirm that the charges at interface can easily follow an ac signal and yield excess capacitance and conductance. The frequency-dependent dielectric constant(ε) and dielectric loss(ε) are subtracted using C and G/ω data at 1.5 V. The ε and ε values are found to be strongly dependent on frequency and voltage, and their large values at low frequencies can be attributed to the excess polarization coming from charges at traps. Plots of ln(σac)–ln(ω) for two structures have two linear regions, with slopes of 0.369 and 1.166 for MS, and of 0.077 and 1.061 for MPS, respectively. From the C 2–V characteristics, the doping acceptor atom concentration(NA) and barrier height(ΦB) for Schottky barrier diodes(SBDs) of MS and MPS types are also obtained to be 1.484 × 1015 and 1.303 × 1015cm 3, and 1.10 and 1.13 eV, respectively. 相似文献
In the present work, a series of [Fe80Ni20–O/SiO2]n multilayer thin films is fabricated using a reactive magnetron sputtering equipment. The thickness of SiO2 interlayer is fixed at 3 nm, while the thickness values of Fe80Ni20–O magnetic films range from 10 nm to 30 nm. All films present obvious in-plane uniaxial magnetic anisotropy. With increasing the Fe80Ni20–O layer thickness, the saturation magnetization increases slightly and the coercivity becomes larger due to the enlarged grain size, which could weaken the soft magnetic property. The results of high frequency magnetic permeability characterization show that films with thin magnetic layer are more suitable for practical applications. When the thickness of Fe80Ni20–O layer is 10 nm, the multilayer film exhibits the most comprehensive high-frequency magnetic property with a real permeability of 300 in gigahertz range. 相似文献
This paper proposes an efficient approach for four-dimensional(4D) parameter estimation of plane waves impinging on a 2-L shape array. The 4D parameters include amplitude, frequency and the two-dimensional(2D) direction of arrival,namely, azimuth and elevation angles. The proposed approach is based on memetic computation, in which the global optimizer, particle swarm optimization is hybridized with a rapid local search technique, pattern search. For this purpose,a new multi-objective fitness function is used. This fitness function is the combination of mean square error and the correlation between the normalized desired and estimated vectors. The proposed hybrid scheme is not only compared with individual performances of particle swarm optimization and pattern search, but also with the performance of the hybrid genetic algorithm and that of the traditional approach. A large number of Monte–Carlo simulations are carried out to validate the performance of the proposed scheme. It gives promising results in terms of estimation accuracy, convergence rate, proximity effect and robustness against noise. 相似文献
Enhancement factor K0, which characterizes NMR and EPR frequency shifts for Cs-129Xe, is measured for the first time. The enhancement factor r-o was measured to be (702±41) at 80 ℃ and (653±20) at 90 ℃, using the NMR frequency shift, detected by atomic magnetometer at a low magnetic field of 100 nT. This result is useful for predicting the EPR frequency shifts for Cs and the NMR frequency shifts for 129Xe in spin-exchange cells. 相似文献
Two different methods to model a point absorber wave energy converter(WEC)with direct drive linear power take-off(PTO)are proposed in the present study:the frequency domain(FD)method and the time domain(TD)method.In the FD analysis,the frequency response function(FRF)of the WEC device is obtained via the equation of motion,and the expressions of power capture width in regular and random waves are derived as well.In the TD modeling,based on a state space approximation of the convolution term in the motion equation,both regular wave and random wave simulations are carried out.The regular wave simulation results indicate that the state space approximation is sufficiently accurate and the capture width reaches the maximum in the vicinity of the natural frequency.In the random wave simulations,the effects of buoy size,the PTO damping and wave climate on the power capture width are discussed in detail,which leads to the conclusion that the capture widths are influenced by the natural frequency of the WEC device,peak frequency of the wave spectrum,the amplitude of FRF and PTO damping.Furthermore,the increase of the capture width is at the cost of a relatively large buoy size and PTO damping when control is not included. 相似文献
Pentacene thin‐film transistor with high‐κ TaLaO as gate dielectric has been fabricated and shows a carrier mobility of 0.73 cm2/V s, much higher than that based on pure La2O3 (0.43 cm2/V s) due to the smoother surface of the TaLaO film and thus larger pentacene islands grown on it in the initial stage. Moreover, among various times for fluorine‐plasma treatment on the TaLaO gate dielectric, 100 seconds result in the highest carrier mobility of 1.12 cm2/V s due to (1) smoothest oxide surface achieved by fluorine passivation of oxide traps, as measured by AFM and supported by smallest sub‐threshold swing and lowest low‐frequency noise; (2) the largest pentacene grains grown on the smoothest oxide surface, as demonstrated by AFM.