Performance of Cross-layer Design with Multiple Outdated Estimates in Multiuser MIMO System

By combining adaptive modulation (AM) and automatic repeat request (ARQ) protocol as well as user scheduling, the cross-layer design scheme of multiuser MIMO system with imperfect feedback is presented, and multiple outdated estimates method is proposed to improve the system performance. Based on this method and imperfect feedback information, the closed-form expressions of spectral efficiency (SE) and packet error rate (PER) of the system subject to the target PER constraint are respectively derived. With these expressions, the system performance can be effectively evaluated. To mitigate the effect of delayed feedback, the variable thresholds (VTs) are also derived by means of the maximum a posteriori method, and these VTs include the conventional fixed thresholds (FTs) as special cases. Simulation results show that the theoretical SE and PER are in good agreement with the corresponding simulation. The proposed CLD scheme with multiple estimates can obtain higher SE than the existing CLD scheme with single estimate, especially for large delay. Moreover, the CLD scheme with VTs outperforms that with conventional FTs

Calorimetric Evidence of Strong-Coupling Multiband Superconductivity in Fe(Te0.57Se0.43) Single Crystal

We have investigated the specific heat of optimally-doped iron chalcogenide superconductor Fe(Te0.57Se0.43) with a high-quality single crystal sample. The electronic specific heat Ce of this sample has been successfully separated from the phonon contribution using the specific heat of a non-superconducting sample (Fe0.90Cu0.10)(Te0.57Se0.43) as a reference. The normal state Sommerfeld coefficient gamma_n of the superconducting sample is found to be ~ 26.6 mJ/mol K^2, indicating intermediate electronic correlation. The temperature dependence of Ce in the superconducting state can be best fitted using a double-gap model with 2Delta_s(0)/kBTc = 3.92 and 2Delta_l(0)/kBTc = 5.84. The large gap magnitudes derived from fitting, as well as the large specific heat jump of Delta_Ce(Tc)/gamma_n*Tc ~ 2.11, indicate strong-coupling superconductivity. Furthermore, the magnetic field dependence of specific heat shows strong evidence for multiband superconductivity

Identification and expression analysis of CYP4G25 gene from the Chinese oak silkworm (Antheraea pernyi)

CYP450 plays an important role in physiological metabolism. A CYP4G25 gene of P450 family was cloned from Antheraea pernyi using reverse transcriptase-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE-PCR). Sequence analysis revealed that this gene was 2112 bp long and has 97.5% identity with Antheraea yamamai CYP4G25. Semi-quantitative polymerase chain reaction (PCR) showed that the expression of A. pernyi CYP4G25 was found in various tissues with no significant changes. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis demonstrated that a 63.6 KD recombinant protein was successfully expressed in Escherichia coli cells and its expression was not remarkably changed under induction by different isopropyl-β-D-thiogalactopyranoside (IPTG) concentration.Key words: Antheraea pernyi, CYP4G25, expression, cytochrome P450

Coupling of electronic and magnetic properties in Fe1+y(Te1-xSex)

We have studied the coupling of electronic and magnetic properties in Fe1+y(Te1-xSex) via systematic specific heat, magnetoresistivity, and Hall coefficient measurements on two groups of samples with y = 0.02 and 0.1. In the y = 0.02 series, we find that the 0.09 < x < 0.3 composition region, where superconductivity is suppressed, has large Sommerfeld coefficient Gamma (~55-65 mJ/mol K^2), positive Hall coefficient R_H and negative magnetoresistance MR at low temperature, in sharp contrast with the x=0.4-0.5 region where Gamma drops to ~ 26 mJ/mol K^2 and R_H / MR becomes negative/positive at low temperature. Dramatic changes of Gamma, as well as sign reversal in low-temperature RH and MR, are also observed across the x~0.1 boundary where the long-range antiferromagnetic order is suppressed. However, for the system with rich interstitial excess Fe (y = 0.1), where bulk superconductivity is suppressed even for x=0.4-0.5, the variations of Gamma, R_H and MR with x are distinct from those seen in y = 0.02 system: Gamma is ~40 mJ/mol K^2 for 0.1 < x < 0.3, and drops to ~ 34 mJ/mol K^2 for x = 0.4-0.5; R_H and MR does not show any sign reversal as x is increased above 0.3. We will show that all these results can be understood in light of the evolution of the incoherent magnetic scattering by (pi,0) magnetic fluctuations with Se concentration. In addition, with the suppression of magnetic scattering by magnetic field, we observed the surprising effect of a remarkable increase in the superconducting volume fraction under moderate magnetic fields for x=0.3-0.4 samples in the y = 0.02 system.Comment: To be appeared in PR

Biological Nitrogen Removal through Nitritation Coupled with Thiosulfate-Driven Denitritation.

A novel biological nitrogen removal system based on nitritation coupled with thiosulfate-driven denitritation (Nitritation-TDD) was developed to achieve a high nitrogen removal rate and low sludge production. A nitritation sequential batch reactor (nitritation SBR) and an anoxic up-flow sludge bed (AnUSB) reactor were applied for effective nitritation and denitritation, respectively. Above 75% nitrite was accumulated in the nitritation SBR with an influent ammonia loading rate of 0.43 kg N/d/m(3). During Nitritation-TDD operation, particle sizes (d50) of the sludge decreased from 406 to 225 um in nitritation SBR and from 327-183 um in AnUSB reactor. Pyrosequencing tests revealed that ammonium-oxidizing bacteria (AOB) population was stabilized at approximately 7.0% (calculated as population of AOB-related genus divided by the total microbial population) in the nitritation SBR. In contrast, nitrite-oxidizing bacteria (NOB) population decreased from 6.5-0.6% over the same time, indicating the effective nitrite accumulation in the nitritation SBR. Thiobacillus, accounting for 34.2% in the AnUSB reactor, was mainly responsible for nitrogen removal via autotrophic denitritation, using an external source of thiosulfate as electron donor. Also, it was found that free nitrous acid could directly affect the denitritation activity

Deep Learning-assisted Accurate Defect Reconstruction Using Ultrasonic Guided Waves:一种基于深度学习的超声导波缺陷重构方法

Ultrasonic guided wave technology has played a significant role in the field of nondestructive testing due to its advantages of high propagation efficiency and low energy consumption. At present, the existing methods for structural defect detection and quantitative reconstruction of defects by ultrasonic guided waves are mainly derived from the guided wave scattering theory. However, taking into account the high complexity in guided wave scattering problems, assumptions such as Born approximation used to derive theoretical solutions lead to poor quality of the reconstructed results. Other methods, for example, optimizing iteration, improve the accuracy of reconstruction, but the time cost in the process of detection has remarkably increased. To address these issues, a novel approach to quantitative reconstruction of defects based on the integration of convolutional neural network with guided wave scattering theory has been proposed in this paper. The neural network developed by this deep learning-assisted method has the ability to quantitatively predict the reconstruction of defects, reduce the theoretical model error and eliminate the impact of noise pollution in the process of inspection on the accuracy of results. To demonstrate the advantage of the developed method for defect reconstruction, the thinning defect reconstructions in plate have been examined. Results show that this approach has high levels of efficiency and accuracy for reconstruction of defects in structures. Especially, for the reconstruction of the rectangle defect, the result by the proposed method is nearly 200% more accurate than the solution by the method of wavenumber-space transform. For the signals polluted with Gaussian noise, i.e., 15 db, the proposed method can improve the accuracy of reconstruction of defects by 71% as compared with the quality of results by the tradional method of wavenumber-space transform. In practical applications, the integration of theoretical reconstruction models with the neural network technique can provide a useful insight into the high-precision reconstruction of defects in the field of non-destruction testing