Power-line interference suppression of MT data based on frequency domain sparse decomposition

Power-line interference is one of the most common noises in magnetotelluric(MT)data.It usually causes distortion at the fundamental frequency and its odd harmonics,and may also affect other frequency bands.Although trap circuits are designed to suppress such noise in most of the modern acquisition devices,strong interferences are still found in MT data,and the power-line interference will fluctuate with the changing of load current.The fixed trap circuits often fail to deal with it.This paper proposes an alternative scheme for power-line interference removal based on frequency-domain sparse decomposition.Firstly,the fast Fourier transform of the acquired MT signal is performed.Subsequently,a redundant dictionary is designed to match with the power-line interference which is insensitive to the useful signal.Power-line interference is separated by using the dictionary and a signal reconstruction algorithm of compressive sensing called improved orthogonal matching pursuit(IOMP).Finally,the frequency domain data are switched back to the time domain by the inverse fast Fourier transform.Simulation experiments and real data examples from Lu-Zong ore district illustrate that this scheme can effectively suppress the power-line interference and significantly improve data quality.Compared with time domain sparse decomposition,this scheme takes less time consumption and acquires better results.

Cognitive interference decision method for air defense missile fuze based on reinforcement learning

To solve the problem of the low interference success rate of air defense missile radio fuzes due to the unified interference form of the traditional fuze interference system,an interference decision method based Q-learning algorithm is proposed.First,dividing the distance between the missile and the target into multiple states to increase the quantity of state spaces.Second,a multidimensional motion space is utilized,and the search range of which changes with the distance of the projectile,to select parameters and minimize the amount of ineffective interference parameters.The interference effect is determined by detecting whether the fuze signal disappears.Finally,a weighted reward function is used to determine the reward value based on the range state,output power,and parameter quantity information of the interference form.The effectiveness of the proposed method in selecting the range of motion space parameters and designing the discrimination degree of the reward function has been verified through offline experiments involving full-range missile rendezvous.The optimal interference form for each distance state has been obtained.Compared with the single-interference decision method,the proposed decision method can effectively improve the success rate of interference.

Flexible, Transparent and Conductive Metal Mesh Films with Ultra‑High FoM for Stretchable Heating and Electromagnetic Interference Shielding

Despite the growing demand for transparent conductive films in smart and wearable electronics for electromagnetic interference(EMI)shielding,achieving a flexible EMI shielding film,while maintaining a high transmittance remains a significant challenge.Herein,a flexible,transparent,and conductive copper(Cu)metal mesh film for EMI shielding is fabricated by self-forming crackle template method and electroplating technique.The Cu mesh film shows an ultra-low sheet resistance(0.18Ω□^(-1)),high transmittance(85.8%@550 nm),and ultra-high figure of merit(>13,000).It also has satisfactory stretchability and mechanical stability,with a resistance increases of only 1.3%after 1,000 bending cycles.As a stretchable heater(ε>30%),the saturation temperature of the film can reach over 110°C within 60 s at 1.00 V applied voltage.Moreover,the metal mesh film exhibits outstanding average EMI shielding effectiveness of 40.4 dB in the X-band at the thickness of 2.5μm.As a demonstration,it is used as a transparent window for shielding the wireless communication electromagnetic waves.Therefore,the flexible and transparent conductive Cu mesh film proposed in this work provides a promising candidate for the next-generation EMI shielding applications.

3D‑Printed Carbon‑Based Conformal Electromagnetic Interference Shielding Module for Integrated Electronics

Electromagnetic interference shielding(EMI SE)modules are the core com-ponent of modern electronics.However,the tra-ditional metal-based SE modules always take up indispensable three-dimensional space inside electronics,posing a major obstacle to the integra-tion of electronics.The innovation of integrating 3D-printed conformal shielding(c-SE)modules with packaging materials onto core electronics offers infinite possibilities to satisfy ideal SE func-tion without occupying additional space.Herein,the 3D printable carbon-based inks with various proportions of graphene and carbon nanotube nanoparticles are well-formulated by manipulating their rheological peculiarity.Accordingly,the free-constructed architectures with arbitrarily-customized structure and multifunctionality are created via 3D printing.In particular,the SE performance of 3D-printed frame is up to 61.4 dB,simultaneously accompanied with an ultralight architecture of 0.076 g cm^(-3) and a superhigh specific shielding of 802.4 dB cm3 g^(-1).Moreover,as a proof-of-concept,the 3D-printed c-SE module is in situ integrated into core electronics,successfully replacing the traditional metal-based module to afford multiple functions for electromagnetic compatibility and thermal dissipa-tion.Thus,this scientific innovation completely makes up the blank for assembling carbon-based c-SE modules and sheds a brilliant light on developing the next generation of high-performance shielding materials with arbitrarily-customized structure for integrated electronics.

Layered Structural PBAT Composite Foams for Efficient Electromagnetic Interference Shielding

The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable manufacturing.In this work,magnetic poly(butyleneadipate-coterephthalate)(PBAT)microspheres were firstly synthesized via phase separation method,then PBAT composite foams with layered structure was constructed through the supercritical carbon dioxide foaming and scraping techniques.The merits of integrating ferroferric oxideloaded multi-walled carbon nanotubes(Fe3O4@MWCNTs)nanoparticles,a microcellular framework,and a highly conductive silver layer have been judiciously orchestrated within this distinctive layered configuration.Microwaves are consumed throughout the process of“absorption-reflection-reabsorption”as much as possible,which greatly declines the secondary radiation pollution.The biodegradable PBAT composite foams achieved an EMI shielding effectiveness of up to 68 dB and an absorptivity of 77%,and authenticated favorable stabilization after the tape adhesion experiment.

Joint alignment and steering to manage interference

In wireless communication networks,mobile users in overlapping areas may experience severe interference,therefore,designing effective Interference Management(IM)methods is crucial to improving network performance.However,when managing multiple disturbances from the same source,it may not be feasible to use existing IM methods such as Interference Alignment(IA)and Interference Steering(IS)exclusively.It is because with IA,the aligned interference becomes indistinguishable at its desired Receiver(Rx)under the cost constraint of Degrees-of-Freedom(DoF),while with IS,more transmit power will be consumed in the direct and repeated application of IS to each interference.To remedy these deficiencies,Interference Alignment Steering(IAS)is proposed by incorporating IA and IS and exploiting their advantages in IM.With IAS,the interfering Transmitter(Tx)first aligns one interference incurred by the transmission of one data stream to a one-dimensional subspace orthogonal to the desired transmission at the interfered Rx,and then the remaining interferences are treated as a whole and steered to the same subspace as the aligned interference.Moreover,two improved versions of IAS,i.e.,IAS with Full Adjustment at the Interfering Tx(IAS-FAIT)and Interference Steering and Alignment(ISA),are presented.The former considers the influence of IA on the interfering user-pair's performance.The orthogonality between the desired signals at the interfered Rx can be maintained by adjusting the spatial characteristics of all interferences and the aligned interference components,thus ensuring the Spectral Efficiency(SE)of the interfering communication pairs.Under ISA,the power cost for IS at the interfered Tx is minimized,hence improving SE performance of the interfered communication-pairs.Since the proposed methods are realized at the interfering and interfered Txs cooperatively,the expenses of IM are shared by both communication-pairs.Our in-depth simulation results show that joint use of IA and IS can effectively manage multiple disturbances from the same source and improve the system's SE.

Off-Grid Compressed Channel Estimation with Parallel Interference Cancellation for Millimeter Wave Massive MIMO

Millimeter wave(mmWave)massive multiple-input multiple-output(MIMO)plays an important role in the fifth-generation(5G)mobile communications and beyond wireless communication systems owing to its potential of high capacity.However,channel estimation has become very challenging due to the use of massive MIMO antenna array.Fortunately,the mmWave channel has strong sparsity in the spatial angle domain,and the compressed sensing technology can be used to convert the original channel matrix into the sparse matrix of discrete angle grid.Thus the high-dimensional channel matrix estimation is transformed into a sparse recovery problem with greatly reduced computational complexity.However,the path angle in the actual scene appears randomly and is unlikely to be completely located on the quantization angle grid,thus leading to the problem of power leakage.Moreover,multiple paths with the random distribution of angles will bring about serious interpath interference and further deteriorate the performance of channel estimation.To address these off-grid issues,we propose a parallel interference cancellation assisted multi-grid matching pursuit(PIC-MGMP)algorithm in this paper.The proposed algorithm consists of three stages,including coarse estimation,refined estimation,and inter-path cyclic iterative inter-ference cancellation.More specifically,the angular resolution can be improved by locally refining the grid to reduce power leakage,while the inter-path interference is eliminated by parallel interference cancellation(PIC),and the two together improve the estimation accuracy.Simulation results show that compared with the traditional orthogonal matching pursuit(OMP)algorithm,the normalized mean square error(NMSE)of the proposed algorithm decreases by over 14dB in the case of 2 paths.

Liquid Metal Grid Patterned Thin Film Devices Toward Absorption‑Dominant and Strain‑Tunable Electromagnetic Interference Shielding

The demand of high-performance thin-film-shaped deformable electromagnetic interference(EMI)shielding devices is increasing for the next generation of wearable and miniaturized soft electronics.Although highly reflective conductive materials can effectively shield EMI,they prevent deformation of the devices owing to rigidity and generate secondary electromagnetic pollution simultaneously.Herein,soft and stretchable EMI shielding thin film devices with absorption-dominant EMI shielding behavior is presented.The devices consist of liquid metal(LM)layer and LM grid-patterned layer separated by a thin elastomeric film,fabricated by leveraging superior adhesion of aerosol-deposited LM on elastomer.The devices demonstrate high electromagnetic shielding effectiveness(SE)(SE_(T) of up to 75 dB)with low reflectance(SER of 1.5 dB at the resonant frequency)owing to EMI absorption induced by multiple internal reflection generated in the LM grid architectures.Remarkably,the excellent stretchability of the LM-based devices facilitates tunable EMI shielding abilities through grid space adjustment upon strain(resonant frequency shift from 81.3 to 71.3 GHz@33%strain)and is also capable of retaining shielding effectiveness even after multiple strain cycles.This newly explored device presents an advanced paradigm for powerful EMI shielding performance for next-generation smart electronics.

Mitigation of Optical Multipath Interference Algorithms in IM-DD Transmission System

This paper aimed to propose two algorithms,DA-M and RF-M,of reducing the impact of multipath interference(MPI)on intensity modulation direct detection(IM-DD)systems,particularly for four-level pulse amplitude modulation(PAM4)systems.DA-M reduced the fluctuation by averaging the signal in blocks,RF-M estimated MPI by subtracting the decision value of the corresponding block from the mean value of a signal block,and then generated interference-reduced samples by subtracting the interference signal from the product of the corresponding MPI estimate and then weighting factor.This paper firstly proposed to separate the signal before decision-making into multiple blocks,which significantly reduced the complexity of DA-M and RF-M.Simulation results showed that the MPI noise of 28 GBaud IMDD system under the linewidths of 1e5 Hz,1e6 Hz and 10e6 Hz can be effectively alleviated.

Inter-layer interference for multi-layered tight gas reservoir in the absence and presence of movable water

Due to the dissimilarity among different producing layers,the influences of inter-layer interference on the production performance of a multi-layer gas reservoir are possible.However,systematic studies of inter-layer interference for tight gas reservoirs are really limited,especially for those reservoirs in the presence of water.In this work,five types of possible inter-layer interferences,including both absence and presence of water,are identified for commingled production of tight gas reservoirs.Subsequently,a series of reservoir-scale and pore-scale numerical simulations are conducted to quantify the degree of influence of each type of interference.Consistent field evidence from the Yan'an tight gas reservoir(Ordos Basin,China)is found to support the simulation results.Additionally,suggestions are proposed to mitigate the potential inter-layer interferences.The results indicate that,in the absence of water,commingled production is favorable in two situations:when there is a difference in physical properties and when there is a difference in the pressure system of each layer.For reservoirs with a multi-pressure system,the backflow phenomenon,which significantly influences the production performance,only occurs under extreme conditions(such as very low production rates or well shut-in periods).When water is introduced into the multi-layer system,inter-layer interference becomes nearly inevitable.Perforating both the gas-rich layer and water-rich layer for commingled production is not desirable,as it can trigger water invasion from the water-rich layer into the gas-rich layer.The gas-rich layer might also be interfered with by water from the neighboring unperforated water-rich layer,where the water might break the barrier(eg weak joint surface,cement in fractures)between the two layers and migrate into the gas-rich layer.Additionally,the gas-rich layer could possibly be interfered with by water that accumulates at the bottom of the wellbore due to gravitational differentiation during shut-in operations.

Experimental Study on Vortex-Induced Vibration of Rough Risers with Coupling Interference Effect Under Side-by-Side Arrangement

A vortex-induced vibration(VIV)experiment of rough risers with coupling interference effect under a side-by-side arrangement was carried out in a wave-current combined flume.The roughness of the riser was characterized by arranging different specifications of surface attachments on the surface of the riser.Rough risers with three different roughnesses were arranged side by side with smooth risers to explore the VIV response of the riser under the combined action of roughness and interference effect,and to reveal the coupling mechanism between roughness and interference effect.The experimental results show that,compared with that of a smooth riser,the VIV of a rough riser under the coupling interference effect has a wider"lock-in"region,and the displacement decreases more significantly at a high reduced velocity,which is more likely to excite higher-order modes and frequency responses.In addition,the displacement response and frequency response of the smooth riser are not significantly affected by wake interference from the rough riser,which is caused by the decrease of the wake region due to the delay of the boundary layer separation point of the rough riser.

Experimental Study on Vortex-Induced Vibration of Rough Risers Coupling with Interference Effect in Tandem Arrangement

In order to study the response law of vortex-induced vibration(VIV)of marine risers under the combined action of roughness and interference effects,and to reveal the coupling mechanism of roughness and interference effects on the riser,a VIV experiment of rough risers in tandem arrangement was conducted in a wave−current combined flume.The experiment characterized the risers’roughness by arranging different specifications of attachments on the surface of the risers.Three rough risers with different roughness and smooth risers were arranged in tandem arrangement,with the rough risers arranged downstream.The experimental results indicate that the suppression of the attachments on the downstream risers’vibration are more significant both in the CF and IL directions as the reduced velocity increases.For the downstream riser,the amplitude response of rough riser is more significantly weakened compared with the smooth one at high reduced velocity.For the upstream risers,changes in the roughness and spacing ratio have an impact on their‘lock-in’region.When the roughness of downstream risers is relatively large(0.1300)and the spacing between risers is small(S/D=4.0),the reduced velocity range of‘lock-in’region in the CF direction of upstream risers is obviously expanded,and the displacement in the‘lock-in’region is severer.

Trunk‑Inspired SWCNT‑Based Wrinkled Films for Highly‑Stretchable Electromagnetic Interference Shielding and Wearable Thermotherapy

Nowadays,the increasing electromagnetic waves generated by wearable devices are becoming an emerging issue for human health,so stretchable electromagnetic interference(EMI)shielding materials are highly demanded.Elephant trunks are capable of grabbing fragile vegetation and tearing trees thanks not only to their muscles but also to their folded skins.Inspired by the wrinkled skin of the elephant trunks,herein,we propose a winkled conductive film based on single-walled carbon nanotubes(SWCNTs)for multifunctional EMI applications.The conductive film has a sandwich structure,which was prepared by coating SWCNTs on both sides of the stretched elastic latex cylindrical substrate.The shrinking-induced winkled conductive network could withstand up to 200%tensile strain.Typically,when the stretching direction is parallel to the polarization direction of the electric field,the total EMI shielding effectiveness could surprisingly increase from 38.4 to 52.7 dB at 200%tensile strain.It is mainly contributed by the increased connection of the SWCNTs.In addition,the film also has good Joule heating performance at several voltages,capable of releasing pains in injured joints.This unique property makes it possible for strain-adjustable multifunctional EMI shielding and wearable thermotherapy applications.

Color-polarization synergistic target detection method considering shadow interference

Aiming at the problem of shadow interference in UAV's ground reconnaissance,a color and polarization synergistic target detection method is proposed for anti-shadow interference,based on the influence of two physical characteristics(wavelength and polarization)under different illuminations.A valid fusion strategy is proposed via integrating two separate detection results on color and polarization images.Moreover,a local enhancement and recognition module(LER)is introduced to boost the performance.Based on our built dataset,experimental results show that our method achieves mAPof 87.76%,and12.37%higher than that of color image and 14.68%higher than that of polarization image.

RNA interference reveals chloride channel 7 gene helps short-term hypersalinity stress resistance in Hong Kong oyster Crassostrea hongkongensis

The chloride channel 7 gene(CLC 7)of the Hong Kong oyster Crassostrea hongkongensis was cloned and named ChCLC 7.The cDNA was 2572 bp in length,with a 5′non-coding region containing 25 bp,a 3′non-coding region containing 327 bp,and an open reading frame of 2298 bp.ChCLC 7 has 96.8%and 92.1%homology with CLC 7 of Crassostrea gigas and Crassostrea virginica,respectively,and it was clustered with CLC 7 of C.gigas and C.virginica.QRT-PCR showed that ChCLC 7 was expressed in all eight tissues,with the highest in adductor muscle and second in gill.The ChCLC 7 expression pattern in gill was altered significantly under high salinity stress with an overall upward and then downward trend.After RNA interference,the expression of ChCLC 7 and survival rate of oyster under high salinity stress was reduced significantly,and so did the concentration of hemolymph chloride ion in 48-96 h after RNA interference.We believed that ChCLC 7 could play an important role in osmoregulation of C.hongkongensis by regulating Cl^(-)transport.This study provided data for the analysis of molecular mechanism against oyster salinity stress.

The characteristics of negative corona discharge and radio interference at different altitudes based on coaxial wire-cylinder gap

The corona discharge from transmission lines in high-altitude areas is more severe than at lower altitudes. The radio interference caused thereby is a key factor to be considered when designing transmission lines. To study the influence of altitude on negative corona characteristics, an experimental platform comprising a movable small corona cage was established: experiments were conducted at four altitudes in the range of 1120-4320 m, and data on the corona current pulse and radio interference level of 0.8-mm diameter fine copper wire under different negative voltages were collected. The experimental results show that the average amplitude, repetition frequency and average current of the corona current pulse increase with increasing altitude. The dispersion of pulse amplitude increases with increase in altitude, while the randomness of the pulse interval decreases continuously. Taking the average current as an intermediate variable,the relationship between radio interference level and altitude is obtained. The result of this research has some significance for understanding the corona discharge characteristics of ultra-highvoltage lines.

Self‑Assembly of Binderless MXene Aerogel for Multiple‑Scenario and Responsive Phase Change Composites with Ultrahigh Thermal Energy Storage Density and Exceptional Electromagnetic Interference Shielding

The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs.

A CSMA/CA based MAC protocol for hybrid Power-line/Visible-light communication networks:Design and analysis

Hybrid Power-line/Visible-light Communication(HPVC)network has been one of the most promising Cooperative Communication(CC)technologies for constructing Smart Home due to its superior communication reliability and hardware efficiency.Current research on HPVC networks focuses on the performance analysis and optimization of the Physical(PHY)layer,where the Power Line Communication(PLC)component only serves as the backbone to provide power to light Emitting Diode(LED)devices.So designing a Media Access Control(MAC)protocol remains a great challenge because it allows both PLC and Visible Light Communication(VLC)components to operate data transmission,i.e.,to achieve a true HPVC network CC.To solve this problem,we propose a new HPC network MAC protocol(HPVC MAC)based on Carrier Sense Multiple Access/Collision Avoidance(CSMA/CA)by combining IEEE 802.15.7 and IEEE 1901 standards.Firstly,we add an Additional Assistance(AA)layer to provide the channel selection strategies for sensor stations,so that they can complete data transmission on the selected channel via the specified CSMA/CA mechanism,respectively.Based on this,we give a detailed working principle of the HPVC MAC,followed by the construction of a joint analytical model for mathematicalmathematical validation of the HPVC MAC.In the modeling process,the impacts of PHY layer settings(including channel fading types and additive noise feature),CSMA/CA mechanisms of 802.15.7 and 1901,and practical configurations(such as traffic rate,transit buffer size)are comprehensively taken into consideration.Moreover,we prove the proposed analytical model has the solvability.Finally,through extensive simulations,we characterize the HPVC MAC performance under different system parameters and verify the correctness of the corresponding analytical model with an average error rate of 4.62%between the simulation and analytical results.

Full-domain collaborative deployment method of multiple interference sources and evaluation of its deployment effect

This paper realizes the full-domain collaborative deployment of multiple interference sources of the global satellite navigation system(GNSS)and evaluates the deployment effect to enhance the ability to disturb the attacker and the capability to defend the GNSS during navigation countermeasures.Key evaluation indicators for the jamming effect of GNSS suppressive and deceptive jamming sources are first created,their evaluation models are built,and their detection procedures are sorted out,as the basis for determining the deployment principles.The principles for collaboratively deploying multi-jamming sources are developed to obtain the deployment structures(including the required number,structures in demand,and corresponding positions)of three single interference sources required by collaboratively deploying.Accordingly,simulation and hardware-in-loop testing results are presented to determine a rational configuration of the collaborative deployment of multi-jamming sources in the set situation and further realize the full-domain deployment of an interference network from ground,air to space.Varied evaluation indices for the deployment effect are finally developed to evaluate the deployment effect of the proposed configuration and further verify its reliability and rationality.

A design scheme for interference suppression based on CWBIM

An interference suppression design scheme based on conjugate weighted butterfly interleaving mapping(CWBIM)is proposed for inter-carrier interference(ICI)and inter-subband interference(IBI)in the received signals of universal filtered multi-carrier(UFMC)systems.It applies an interleaving mapping operation to subtract the interference coefficients of adjacent terms in ICI and IBI twice,thereby achieving suppression effects similar to the self-cancellation(SC)algorithm while maintaining the original data transmission efficiency.Meanwhile,conjugate and complex weighting operations can effectively suppress the impact of phase rotation errors in high-speed mobile channel environments,thereby further improving the bit error rate(BFR)performance of the system,Moreover,butterfly operation can effectively control the computational complexity of the interleaving mapping process.Theoretical analysis and simulation results show that,compared with the PSC-UFMC algorithm,the CWBIM-UFMC scheme proposed in this paper can effectively suppress ICI and IBI in the received signal without compromising data transmission efficiency and reducing computational complexity,thereby achieving good BER performance of the system.