8,611 research outputs found
Clapeyron equation and phase equilibrium properties in higher dimensional charged topological dilaton AdS black holes with a nonlinear source
Using Maxwell's equal area law, we discuss the phase transition of higher
dimensional charged topological dilaton AdS black holes with a nonlinear
source. The coexisting region of the two phases is found and we depict the
coexistence region in diagrams. The two-phase equilibrium curves in
diagrams are plotted, and we take the first order approximation of volume
in the calculation. To better compare with a general thermodynamic system, the
Clapeyron equation is derived for higher dimensional charged topological black
hole with a nonlinear source. The latent heat of isothermal phase transition is
investigated. We also study the effect of the parameters of the black hole on
the region of two-phases coexistence. The results show that the black hole may
go through a small-large phase transition similar to those of usual non-gravity
thermodynamic systems.Comment: 21 pages,25 figures. published version in EPJC. arXiv admin note:
substantial text overlap with arXiv:1411.7202; text overlap with
arXiv:1506.01786, arXiv:hep-th/0605042 by other author
Exploiting smallest error to calibrate non-linearity in SAR ADCs
This paper presents a statistics-optimised organisation technique to achieve better element matching in Successive Approximation Register (SAR) Analog-to-Digital Converter (ADC) in smart sensor systems. We demonstrate the proposed technique ability to achieve a significant improvement of around 23 dB on Spurious Free Dynamic Range (SFDR) of the ADC than the conventional, testing with a capacitor mismatch σu = 0.2% in a 14 bit SAR ADC system. For the static performance, the max root mean square (rms) value of differential nonlinearity (DNL) reduces from 1.63 to 0.20 LSB and the max rms value of integral nonlinearity (INL) reduces from 2.10 to 0.21 LSB. In addition, it is demonstrated that by applying grouping optimisation and strategy optimisation, the performance boosting on SFDR can be effectively achieved. Such great improvement on the resolution of the ADC only requires an off-line pre-processing digital part
Comparator Design in Sensors for Environmental Monitoring
This paper presents circuit design considerations of comparator in analog-to-digital converters (ADC) applied for a portable, low-cost and high performance nano-sensor chip which can be applied to detect the airborne magnetite pollution nano particulate matter (PM) for environmental monitoring. High-resolution ADC plays a vital important role in high perfor-mance nano-sensor, while high-resolution comparator is a key component in ADC. In this work, some important design issues related to comparators in analog-to-digital converters (ADCs) are discussed, simulation results show that the resolution of the comparator proposed can achieve 5µV , and it is appropriate for high-resolution application
Deciphering a novel image cipher based on mixed transformed Logistic maps
Since John von Neumann suggested utilizing Logistic map as a random number
generator in 1947, a great number of encryption schemes based on Logistic map
and/or its variants have been proposed. This paper re-evaluates the security of
an image cipher based on transformed logistic maps and proves that the image
cipher can be deciphered efficiently under two different conditions: 1) two
pairs of known plain-images and the corresponding cipher-images with
computational complexity of ; 2) two pairs of chosen plain-images
and the corresponding cipher-images with computational complexity of ,
where is the number of pixels in the plain-image. In contrast, the required
condition in the previous deciphering method is eighty-seven pairs of chosen
plain-images and the corresponding cipher-images with computational complexity
of . In addition, three other security flaws existing in most
Logistic-map-based ciphers are also reported.Comment: 10 pages, 2 figure
Observation of unstable fast component in OSL of quartz
Optically stimulated luminescence (OSL) dating has been applied to quartz grains extracted from a sedimentary layer containing stone tools from the bank of Salawusu River, Mu Us desert in central China. Severe age underestimation was observed by applying the single-aliquot regenerative dose (SAR) dating method when compared with the isochron infrared stimulated luminescence (iIRSL) dating results using potassium-rich feldspar grains of different grain sizes. Preheating plateau and dose recovery tests suggest that the SAR protocol is robust for this sample. Component resolving indicates that the OSL signals were dominated by the fast component. However, the fast component is thermally unstable as shown by pulse-annealing measurements and single-grain study. This leads to OSL age underestimation. To overcome this problem, a method was proposed by combining equivalent dose (De) determination and pulse-annealing experiments using single-grain measurements to select only those grains with the thermally stable signals. For those quartz grains with thermally stable OSL signals, the ages obtained are consistent with iIRSL results
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