Nonlinear distortion compensation algorithm aided by channel estimation of memoryless power amplifier for OTFS receiver

A compensation algorithm for OTFS receiver was proposed to solve the problem of transmission signal distortion caused by the nonlinear characteristics of power amplifier (PA) in the orthogonal time frequency space (OTFS) system.The channel state information was estimated by Bussgang theorem combined with the complex coefficient polynomial of PA and the average energy of the distortion term.Based on it, the transmitted signal was reconstructed with distortion term and the estimated value was updated for the polynomial normalization.Furthermore, the iterative zero-forcing equalization algorithm was employed to complete adaptive compensation analysis of the nonlinear distortion at the receiver.The results show that the nonlinear influence on transmission signals is reduced, which caused by Saleh and Rapp models, and BER performance of OTFS system is improved effectively

Investigation on viscosity and non-isothermal crystallization behavior of P-bearing steelmaking slags with varying TiO2 content

The viscous flow and crystallization behavior of CaO-SiO2-MgO-Al2O3-FetO-P2O5-TiO2 steelmaking slags have been investigated over a wide range of temperatures under Ar (High purity, >99.999 pct) atmosphere, and the relationship between viscosity and structure was determined. The results indicated that the viscosity of the slags slightly decreased with increasing TiO2 content. The constructed nonisothermal continuous cooling transformation (CCT) diagrams revealed that the addition of TiO2 lowered the crystallization temperature. This can mainly be ascribed to that addition of TiO2 promotes the formation of [TiO6]-octahedra units and, consequently, the formation of MgFe2O4-Mg2TiO4 solid solution. Moreover, the decreasing viscosity has a significant effect on enhancing the diffusion of ion units, such as Ca2+ and [TiO4]-tetrahedra, from bulk melts to the crystal–melt interface. The crystallization of CaTiO3 and CaSiTiO5 was consequently accelerated, which can improve the phosphorus content in P-enriched phase (n2CaO·SiO2-3CaO·P2O5). Finally, the nonisothermal crystallization kinetics was characterized and the activation energy for the primary crystal growth was derived such that the activation energy increases from −265.93 to −185.41 KJ·mol−1 with the addition of TiO2 content, suggesting that TiO2 lowered the tendency for the slags to crystallize

GUS-YOLO Remote Sensing Target Detection Algorithm Introducing Context Information and Attention Gate

At present, there are still some problems in the remote sensing target detection algorithm based on the general YOLO (you only look once) series, such as not making full use of the global context information of the image, not narrowing the semantic gap in the feature fusion pyramid part, and not suppressing the interference of redundant information. On the basis of combining the advantages of YOLO algorithms, this paper proposes GUS-YOLO (network of global context extraction unit and attention gate-based YOLOS) algorithm. It has a backbone network Global Backbone that can make full use of global context information. Other than that, this algorithm introduces the Attention Gate module into the top-down structure of the fused feature pyramid, which can emphasize the necessary feature information and suppress redundant information. Furthermore, this paper designs the best network structure for the Attention Gate module and proposes the feature fusion structure U-Net of proposed network.  Finally, because the ReLU activation function may lead to the problem that the model gradient is no longer updated, the Attention Gate module uses a learnable SMU (smooth maximum unit) activation function, which can improve the robustness of the model. On the NWPU VHR-10 remote sensing dataset, this algorithm achieves 1.64 percentage points and 9.39 percentage points performance improvement on mAP0.50 and mAP0.75 respectively compared with YOLOV7. Compared with the current 7 mainstream detection algorithms, this algorithm achieves better detection performance

Numerical Investigation of the Combined Influence of Shield Tunneling and Pile Cutting on Underpinning Piles

In this study, the combined influence of shield tunneling and the old pile cutting process on underpinning piles is investigated through finite element method (FEM) modeling based on a shield tunnel project in Nanchang Metro Line 2, China. Numerical models have been developed to analyze the influence of intersection angles and the vertical distance between the underpinning foundation and tunnels on the mechanical responses of underpinning piles during tunnel excavation. Simulation results show that the bending moment of the underpinning piles decreases with increasing vertical distance between the pile and tunnel, and is inversely proportional to the intersection angle between the underpinning beam and tunnel. In addition, the maximum pile bending moment occurs in the buried depth of the tunnel axis, indicating a high risk of damage in this part. According to the simulation results, more attention should be given to the underpinning piles in case a small vertical distance and intersection angle are encountered

Isomeric Effects of Solution Processed Ladderâ Type Nonâ Fullerene Electron Acceptors

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138922/1/solr201700107_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138922/2/solr201700107-sup-0001-SuppData-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138922/3/solr201700107.pd

A response to commenter Ke Lan's comment on our paper published in Nature Communications (2023)14:5782 by J. Yan et al

A response to commenter Ke Lan's comment on our paper published in Nature Communications (2023)14:5782 by J. Yan et a

Evaluating maturity of source rocks by aromatic compounds: A case from Dongling Block, Songliao Basin

The characteristics of the thermal evolution of aromatic maturity parameters, such as methyl phenanthrene, alkylated dibenzothiophene, dehydroxy-tocopherol and triaromatic-sterane series compounds are discussed on the basis of molecular organic geochemistry and GC-MS analysis of the source rocks in the Dongling area of the Songliao Basin. The distribution characteristics of aromatic hydrocarbon chromatography, the methyl phenanthrene index (MPI), the ratio of β/γ dehydroxy-tocopherol, 4-/1-MDBT, 4,6-/1,4-DMDBT, TASC27 (20R)/C28 (20R), the content of the triaromatic-sterane series and vitrinite reflectance measurements all suggest that the Lower Cretaceous Quantou Formation source rock is in the middle stage of maturity, whereas the Lower Cretaceous Yingcheng Formation and the Upper Jurassic Huoshiling Formation source rocks have reached a high maturity stage