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Dual-polarized and real-time reconfigurable metasurface absorber with infrared-coded remote-control system

Nano Research 2022年第8期15卷 7498-7505页

作者： Jiangyong liu Yuping Duan Tuo Zhang lingxi Huang Huifang Pang Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116085China

The reconfigurable metasurfaces which can regulate the microwave absorption performance at the sub wavelength scale provide a possibility to construct intelligent stealth system.However,the existing reconfigurable-metasurface-based absorbers seriously limit the medium and long-distance regulation in practical application due to the complex circuit path and regulation mode.Here,an infrared-coded dual-polarized metasurface absorber(IDMA)with remote-control mode was proposed,which realized the realtime dynamic regulation of the intensity and frequency range of absorption peaks by combining the infrared-coding remotecontrol technology with the active metasurface absorber.The proposed remote-control system can switch the 8-bit binary coding sequences stored in the microcontroller unit(MCU)by an infrared transceiver,so as to regulate the state of active devices under X-and Y-polarizations,respectively.The experimental results showed that the reflection/absorption responses can be regulated by switching different binary codes,and the reflection loss(RL)can be tuned below−7.5 dB(absorptivity over 82%)in wide range of 6.20–18 GHz.Furthermore,the corresponding equivalent circuit model was established and the distributions of surface current and electric field were analyzed to elucidate the dynamic reconfigurable mechanism of the metasurface absorber.The proposed IDMA,which combines intelligent electronic technology with active metasurface absorber,creatively realizes the remote control of active metasurface absorber and opens up a new way for the stealth technology of smart absorber in the future.

关键词： microwave absorption active metasurface reflection/absorption infrared-coded remote-control real-time dynamic control

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Stick-slip nucleation triggering of Wenchuan earthquake

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Geodesy and Geodynamics 2021年第1期12卷 11-20页

作者： Shuangxi Zhang Lingxi Liu Menkui Li Yu Zhang Jie Tang Xuchong Yi Department of Geophysics School of Geodesy and GeomaticsWuhan UniversityWuhan430079China Key Laboratory of Geospace Environment and Geodesy of the Ministry of Education Wuhan University430079WuhanChina

The MS8.0 Wenchuan earthquake occurred on May 12 th,2008 on the steeply reverse fault of the Longmen Shan fault zone,Western China.Catastrophic failure and rupture occurred along the listric sliding surface.Several numerical simulations have been performed to reconfigure the dynamic processes of this strong earthquake.However,few scientific studies on the stick-slip of the listric fault have been conducted.In this study,finite element method is utilized to simulate the instant stick-slip fault responses at the triggering moment.The fault surface is a non-continuous and frictional contact interface.The simulation results demonstrated that the sliding friction and sticking friction interact spatially.This interaction occurred temporarily on swarms of slip patches,rather than the entire fault slipping surface.Stick-slip causes serrated energy release,and transient aseismic slip can occur spontaneously.These tremors propagate from the epicenter upwards to the ground surface.Therefore,they may provide important details on earthquake onset rupture.

关键词： Stick-slip Tremor Wenchuan earthquake Longmen Shan Earthquake triggering Friction Numerical simulation

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The genetic and epigenetic alterations in human hepatocellular carcinoma： a recent update

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Protein & Cell 2014年第9期5卷 673-691页

作者： Ming liu lingxi Jiang Xin-Yuan Guan Department of Clinical Oncology University of Hong Kong Hong Kong China

Hepatocellular carcinoma （HCC） is one of the most frequent human malignancies worldwide with very poor prognosis. It is generally accepted that the progression of HCC is a long-term process with accumulation of multiple genetic and epigenetic alterations, which further lead to the activation of critical oncogenes or inactivation of tumor suppressor genes. HCC is characterized with multiple cancer hallmarks including their ability to proliferate, anti-poptosis, invade, metastasis, as well as the emerging features such as stem cell properties and energy metabolic switch. The irreversible alterations at genetic level could be detected as early as in the pre-neoplastic stages and accumulate during cancer progression. Thus, they might account for the cancer initiating steps and further malignant transformation. In addition to genetic alterations, epigenetic alterations can affect the cancer transcriptome more extensively. Alterations in DNA methylation, histone modification, miRNAs, RNA editing, and IncRNAs might result in disrupted gene regulation networks and substantially contribute to HCC progression. In this review, the genetic and epigenetic alterations which significantly contribute to the malignant capabilities of HCC will be updated and summarized in detail. Further characterization of those critical molecular events might better elucidate the pathogenesis of HCC and provide novel therapeutic targets for treatment of this deadly disease.

关键词： hepatocellular carcinoma （HCC） cancerhallmarks genetic regulation epigenetic regulation,therapeutic targets HCC progression

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Asymmetric electric field distribution enhanced hierarchical metamaterials for radar-infrared compatible camouflage

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Journal of Materials Science & Technology 2023年第15期146卷 10-18页

作者： Tuo Zhang Yuping Duan Jiangyong liu Hao Lei Jingxuan Sun Huifang Pang lingxi Huang Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116085China

Metamaterials are widely used in electromagnetic radiation and camouflage for their flexible wavefront manipulation and polarization over a broad spectrum ranging from microwaves to optics.However,multispectral compatible camouflage faces significant challenges due to tremendous scale differences of unit cells and desired radiative properties in various spectral regimes.This study assembles a micron-scale infrared emitter,a millimeter-scale microwave absorber,and a metal reflector to propose a hierarchical metamaterial that reduces microwave scattering and reflects low-infrared waves.As a proof of concept,laser etching micro-manufactures an upper infrared shielding layer with a periodic metal pattern.At the same time,bottom square frustum metastructure composites are fabricated and optimized based on genetic algorithms.Under the normal incidence transverse electromagnetic wave with a 90°azimuth angle,the hierarchical strategy and infrared unit create an asymmetric electric field distribution of local near-field coupling,which is conducive to generating additional resonance for broadening the absorption bandwidth.Experiments verify the multispectral camouflage,which shows a high absorption efficiency of more than 90%,ranging from 3.6 to 6.2 and from 8.4 to 18 GHz with a total thickness of 4.05 mm(0.049λmax).Due to the non-reflection of surrounding thermal signals in the infrared 2-22μm region,low-infrared emissivity(0.29)metamaterials can adapt to various thermal backgrounds.This methodology can provide a novel route for fabricating multispectral camouflage devices.

关键词： Hierarchical metamaterials Radar-infrared compatible stealth Genetic algorithm Magnetic-dielectric lossy composites Asymmetry

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Recovering Period of Postseismic Fluid Pressure in Fault Valve

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Journal of Earth Science 2015年第4期26卷 530-536页

作者： Shuangxi Zhang Chen Zhang Yu Zhang Chaoyu Zhang Lingxi Liu Mengkui Li School of Geodesy and Geomatics Wuhan University Key Laboratory of Environment and Geodesy Ministry of EducationWuhan

The present study aims to reveal the recovering period of the postseismic fluid pressure in fault zone, offering an insight into earthquake recurrence. Numerical modeling is performed based on a 2D simple layered fault-valve model to simulate the fluid activities within the earthquake fault. In order to demonstrate the features of postseismic fluid pressure in natural state, the interference of tectonic movements is not considered. The recovering period of postseismic fluid pressure includes a sudden- changing period and a much longer fluctuating period. Modeling results show that fault permeability and porosity are sensitive parameters and reversely proportional to the recovering period of the fluid pressure in earthquake fault zone. When the permeability reduces from 10^-15 to 10^-18 m^2, the recovering period increases from 400 to 2 000 yrs, correspondently. The upper and lower fluid pressures are sepa- rated by the valve seal, causing their fluctuations in opposite tendencies.

关键词： recovering period fluid pressure fault valve numerical modeling thermal anomaly.

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Heme oxygenase-1 inhibits neuropathic pain in rats with diabetic mellitus

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Neural Regeneration Research 2012年第29期7卷 2305-2311页

作者： Qian Kong Kang liu lingxi Wu Long Wang Department of Anesthesiology Renmin Hospital of Wuhan University Wuhan 430060 Hubei Province China

A diabetes mellitus model was established through single intraperitoneal injection of streptozotocin into rats. Seven days later, model rats were intraperitoneally administered zinc protoporphyrin, a heme oxygenase-1 inducer, and cobalt protoporphyrin, a heme oxygenase-1 inhibitor, once every two days, for 5 successive weeks. After administration, the paw withdrawal mechanical threshold of diabetic mellitus rats significantly decreased, the myelin sheath of the sciatic nerve thickened or showed vacuole defects, the number of spinal dorsal horn neurons reduced, some neurons degenerated and were necrotic, and heme oxygenase-1 was visible in the cytoplasm of spinal dorsal hom neurons. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling demonstrated that the number of apoptotic neurons increased, which could be inhibited by cobalt protoporphyrin, however, zinc protoporphyrin led to an opposite effect. Our experimental findings indicate that heme oxygenase-1 attenuates neuropathic pain in diabetic mellitus rats through amelioration of peripheral neuropathy and inhibition of spinal dorsal horn neuron apoptosis.

关键词： diabetes mellitus neuropathic pain heme oxygenase-1 cobalt protoporphyrin zinc protoporphyrin neurons apoptosis peripheral nerve injury regeneration neural regeneration

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Mixed-decomposed convolutional network:A lightweight yet efficient convolutional neural network for ocular disease recognition

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CAAI Transactions on Intelligence Technology 2024年第2期9卷 319-332页

作者： Xiaoqing Zhang Xiao Wu Zunjie Xiao lingxi Hu Zhongxi Qiu Qingyang Sun Risa Higashita Jiang liu Research Institute of Trustworthy Autonomous Systems and Department of Computer Science and Engineering Southern University of Science and TechnologyShenzhenChina Tomey Corporation NagoyaJapan Guangdong Provincial Key Laboratory of Brain‐inspired Intelligent Computation Department of Computer Science and EngineeringSouthern University of Science and TechnologyShenzhenChina Singapore Eye Research Institute SingaporeSingapore

Eye health has become a global health concern and attracted broad attention.Over the years,researchers have proposed many state-of-the-art convolutional neural networks(CNNs)to assist ophthalmologists in diagnosing ocular diseases efficiently and precisely.However,most existing methods were dedicated to constructing sophisticated CNNs,inevitably ignoring the trade-off between performance and model complexity.To alleviate this paradox,this paper proposes a lightweight yet efficient network architecture,mixeddecomposed convolutional network(MDNet),to recognise ocular diseases.In MDNet,we introduce a novel mixed-decomposed depthwise convolution method,which takes advantage of depthwise convolution and depthwise dilated convolution operations to capture low-resolution and high-resolution patterns by using fewer computations and fewer parameters.We conduct extensive experiments on the clinical anterior segment optical coherence tomography(AS-OCT),LAG,University of California San Diego,and CIFAR-100 datasets.The results show our MDNet achieves a better trade-off between the performance and model complexity than efficient CNNs including MobileNets and MixNets.Specifically,our MDNet outperforms MobileNets by 2.5%of accuracy by using 22%fewer parameters and 30%fewer computations on the AS-OCT dataset.

关键词： artificial intelligence deep learning deep neural networks image analysis image classification medical applications medical image processing

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The electromagnetic response of composition-regulated honeycomb structural materials used for broadband microwave absorption

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Journal of Materials Science & Technology 2021年第29期88卷 203-214页

作者： Huifang Pang Yuping Duan Xuhao Dai lingxi Huang Xuan Yang Tuo Zhang Xiaoji liu Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian116085China

The undesirable absorption bandwidth is the main limitation for the application of microwave absorbing materials.Noting that the design of structure and composition of absorbing coating allows it to obtain a satisfying absorption bandwidth and to avoid weight increasing,honeycomb and its sandwich structures coated by various absorbant have been developed and measured using an arch measurement system over2-18 GHz.To further understand the absorption mechanisms of honeycomb structural materials,simulation based on finite element method and transmission line theory is performed to analyze the different responses to the applied microwave between honeycomb structural materials and uniform-medium slab materials.The proper composition design allows control over the microwave loss mechanisms,which optimize the coating to possess both of the dielectric and magnetic advantages.For the honeycomb structural materials,the magnetic resonation is found for the first time,which is resulting from the periodic honeycomb walls on both sides of the dielectric cavity(consisting of the aramid paper interlayer and vacuum hexagonal prisms).In addition,the conversion of structure from solid to honeycomb brings about changes in impedance,propagating path,effective wavelength,effective attenuation area,microwave phases,and inductive coupling effect,etc.,which result in a better microwave absorbing performance.The honeycomb sandwich structure coated by CIP/CB/EP with the weight ratio of 4:0.03:1 shows the absorption bandwidth of~9.8 GHz for reflection loss(RL)lower than-10 dB which covers part of the S and C bands and almost the whole X and Ku bands.

关键词： Microwave absorption Structural materials Honeycomb Electromagnetic response

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Point Cloud Classification Using Content-Based Transformer via Clustering in Feature Space

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 231-239页

作者： Yahui liu Bin Tian Yisheng Lv lingxi Li Fei-Yue Wang the State Key Laboratory for Management and Control of Complex Systems Institute of AutomationChinese Academy of SciencesBeijing 100190 the School of Artificial Intelligence University of Chinese Academy of SciencesBeijing 100190 IEEE the Transportation and Autonomous Systems Institute(TASI)and the Department of Electrical and Computer Engineering Purdue School of Engineering and TechnologyIndiana University-Purdue University Indianapolis(IUPUI)Indianapolis 46202 USA

Recently, there have been some attempts of Transformer in 3D point cloud classification. In order to reduce computations, most existing methods focus on local spatial attention,but ignore their content and fail to establish relationships between distant but relevant points. To overcome the limitation of local spatial attention, we propose a point content-based Transformer architecture, called PointConT for short. It exploits the locality of points in the feature space(content-based), which clusters the sampled points with similar features into the same class and computes the self-attention within each class, thus enabling an effective trade-off between capturing long-range dependencies and computational complexity. We further introduce an inception feature aggregator for point cloud classification, which uses parallel structures to aggregate high-frequency and low-frequency information in each branch separately. Extensive experiments show that our PointConT model achieves a remarkable performance on point cloud shape classification. Especially, our method exhibits 90.3% Top-1 accuracy on the hardest setting of ScanObjectN N. Source code of this paper is available at https://***/yahuiliu99/PointC onT.

关键词： Content-based Transformer deep learning feature aggregator local attention point cloud classification

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Atmospheric sulfur hexafluoride in-situ measurements at the Shangdianzi regional background station in China

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Journal of Environmental Sciences 2014年第12期26卷 2451-2458页

作者： Bo Yao lingxi Zhou Lingjun Xia Gen Zhang Lifeng Guo Zhao liu Shuangxi Fang Guangzhou Institute of Geochemistry Chinese Academy of Sciences Chinese Academy of Meteorological Sciences (CAMS) China Meteorological Administration (CMA) University of Chinese Academy of Sciences Nanjing University of Information Science and Technology Meteorological Research Institute of Heilongjiang Province

We present in-situ measurements of atmospheric sulfur hexafluoride（SF6） conducted by an automated gas chromatograph–electron capture detector system and a gas chromatography/mass spectrometry system at a regional background site, Shangdianzi,in China, from June 2009 to May 2011, using the System for Observation of Greenhouse gases in Europe and Asia and Advanced Global Atmospheric Gases Experiment（AGAGE）techniques. The mean background and polluted mixing ratios for SF6 during the study period were 7.22 × 10-12（mol/mol, hereinafter） and 8.66 × 10-12, respectively. The averaged SF6 background mixing ratios at Shangdianzi were consistent with those obtained at other AGAGE stations located at similar latitudes（Trinidad Head and Mace Head）, but larger than AGAGE stations in the Southern Hemisphere（Cape Grim and Cape Matatula）. SF6 background mixing ratios increased rapidly during our study period, with a positive growth rate at 0.30 × 10-12year-1. The peak to peak amplitude of the seasonal cycle for SF6 background conditions was 0.07 × 10-12, while the seasonal fluctuation of polluted conditions was 2.16 × 10-12. During the study period, peak values of SF6 mixing ratios occurred in autumn when local surface horizontal winds originated from W/WSW/SW/SWS/S sectors, while lower levels of SF6 mixing ratios appeared as winds originated from N/NNE/NE/ENE/E sectors.

关键词： Atmospheric sulfur hexafluoride （SF6） In-situ measurement Shangdianzi Seasonality Data analysis

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