Jet formation and penetration performance of a double-layer charge liner with chemically-deposited tungsten as the inner liner

This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double-layer charge liners were fabricated by using CVD to deposit tungsten layers on the inner surfaces of pure T2 copper liners.The microstructures of the tungsten layers were analyzed using a scanning electron microscope(SEM).The feasibility analysis was carried out by pulsed X-rays,slug-retrieval test and static penetration tests.The shaped charge jet forming and penetration law of inner tungsten-coated double-layer liner were studied by numerical simulation method.The results showed that the double-layer liners could form well-shaped jets.The errors between the X-ray test results and the numerical results were within 11.07%.A slug-retrieval test was found that the retrieved slug was similar to a numerically simulated slug.Compared with the traditional pure copper shaped charge jet,the penetration depth of the double-layer shaped charge liner increased by 11.4% and>10.8% respectively.In summary,the test results are good,and the numerical simulation is in good agreement with the test,which verified the feasibility of using the CVD method to fabricate double-layer charge liners with a high-density and high-strength refractory metal as the inner liner.

A Localization Method of High Energy Transients for All-sky Gamma-ray Monitor

Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties and guiding the follow-up observations.Localization based on the relative counts of different detectors has been widely used for all-sky gamma-ray monitors.There are two major methods for this count distribution localization:χ^(2)minimization method and the Bayesian method.Here we propose a modified Bayesian method that could take advantage of both the accuracy of the Bayesian method and the simplicity of the χ^(2)method.With comprehensive simulations,we find that our Bayesian method with Poisson likelihood is generally more applicable for various bursts than the χ^(2)method,especially for weak bursts.We further proposed a location-spectrum iteration approach based on the Bayesian inference,which could alleviate the problems caused by the spectral difference between the burst and location templates.Our method is very suitable for scenarios with limited computation resources or timesensitive applications,such as in-flight localization software,and low-latency localization for rapidly follow-up observations.

Metamaterial-enhanced magnetic resonance imaging:a review

Magnetic resonance imaging(MRI),as a noninvasive and powerful method in modern diagnostics,has been advancing in leaps and bounds.Conventional methods to improve MRI based on increasing the static magnetic field strength are restricted by safety concerns,cost issues,and the impact on patient experience;as such,innovative approaches are required.It has been suggested that metamaterials featuring subwavelength unit cells can be used to take full control of electromagnetic waves and redistribute electromagnetic fields,achieve abundant counterintuitive phenomena,and construct versatile devices.Recently,metamaterials with exotic effective electromagnetic parameters,peculiar dispersion relations,or tailored field distribution of resonant modes have shown promising capabilities in MRI.Herein,we outline the principle of the MRI process,review recent advances in enhancing MRI by employing the unique physical mechanisms of metamaterials,and demystify ways in which metamaterial designs could improve MRI,such as by enhancing the imaging quality,reducing the scanning time,alleviating field inhomogeneities,and increasing patient safety.We conclude by providing our vision for the future of improving MRI with metamaterials.

Efficient and stable wireless power transfer based on the non-Hermitian physics

As one of the most attractive non-radiative power transfer mechanisms without cables,efficient magnetic resonance wireless power transfer(WPT)in the near field has been extensively developed in recent years,and promoted a variety of practical applications,such as mobile phones,medical implant devices and electric vehicles.However,the physical mechanism behind some key limitations of the resonance WPT,such as frequency splitting and size-dependent efficiency,is not very clear under the widely used circuit model.Here,we review the recently developed efficient and stable resonance WPT based on non-Hermitian physics,which starts from a completely different avenue(utilizing loss and gain)to introduce novel functionalities to the resonance WPT.From the perspective of non-Hermitian photonics,the coherent and incoherent effects compete and coexist in the WPT system,and the weak stable of energy transfer mainly comes from the broken phase associated with the phase transition of parity-time symmetry.Based on this basic physical framework,some optimization schemes are proposed,including using nonlinear effect,using bound states in the continuum,or resorting to the system with high-order parity-time symmetry.Moreover,the combination of non-Hermitian physics and topological photonics in multi-coil system also provides a versatile platform for long-range robust WPT with topological protection.Therefore,the non-Hermitian physics can not only exactly predict the main results of current WPT systems,but also provide new ways to solve the difficulties of previous designs.

A Review of the Design and Feasibility of Intelligent Water-Lubrication Bearings

Water-lubrication bearings are critical components in ship operation.However,studies on their maintenance and failure detection are highly limited.The use of sensors to continually monitor the working operation of bearings is a potential approach to solve this problem,which is collectively called intelligent bearings.In this literature review,the recent progress of electrical resistance strain gauges,Fiber Bragg grating,triboelectric nanogenerators,piezoelectric nanogenerators,and thermoelectric sensors for in-situ monitoring is summarized.Future research and design concepts on intelligent water-lubrication bearings are also comprehensively discussed.The findings show that the accident risks,lubrication condition,and remaining life of water-lubricated bearings can be evaluated with the surface temperature,coefficient of friction,and wear volume monitoring.The research work on intelligent water-lubricated bearings is committed to promoting the development of green,electrified,and intelligent technologies for ship propulsion systems,which have important theoretical significance and application value.

Studies for Intervention and Effect Assessment on Arsenism

Chronic exposed to high arsenic via drinking water is worldwide public health problem. A large number of epidemiological studies showed that exposed to arsenic cause the human body skin lesions and also induce cancer, cardiovascular and other kind of diseases. So arsenism not only affect the person’s work capability and life quality but also result in economic losses and mental suffering. How to prevent and control the effects of high arsenic? What intervention is more important and necessary for arsenism? How to scientifically assess the interventions effect of short-term and long-term? Through a systematic follow-up investigation in different high arsenic regions in Inner Mongolia, the environmental arsenic and human body internal arsenic exposure were analyzed, the clinical characteristics and signs of arsenism patients were examined. We established the evaluation system of intervention and control measures for population exposed to high arsenic. This evaluation system and control measures included government and exposed population. For government, change water supply and keep it work well and health education is very important. For exposed population, improving the diet and treating the symptoms or signs related to arsenic is more necessary. Arsenic in human body such as nail or urine sample arsenic must be reduced to normal value and this index show that the subject if still or not expose to high arsenic.

Fabrication of magnetically responsive anti-fouling and easy-cleaning nanofiber membrane and its application for efficient oil-water emulsion separation

The magnetically responsive anti-fouling nanofiber membrane(MRANM)was fabricated for efficient oilwater emulsion separation,which could be cleaned using oscillating magnetic field.MRANM was prepared by grafting superparamagnetic Fe_(3)O_(4) nanoparticles onto the surface of electrospun polyacrylonitrile nanofiber membrane(PANM).Compared with PANM,the water contact angle of MRANM decreased from 104°to 0°,indicating that the hydrophilicity of the membrane was significantly improved.For the emulsions of hexadecane,octane and rapeseed oil,the separation efficiency was 98.04%,96.59%and 92.67%,respectively.After the treatments in oscillating magnetic field,the separation efficiency kept above 95%after 8 times recycling,which indicated that the MRANM had good regenerability and reusability.The as-fabricated membrane with magnetic responsiveness facilitated an effective method for solving the membrane fouling problem during practical applications of separation high viscosity oil-water emulsion.

Anomalous broadband Floquet topological metasurface with pure site rings

Photonic and acoustic topological insulators exhibiting one-way transportation that is robust against defects and impurities are typically realized in coupled arrays of two-dimensional ring resonators.These systems have produced a series of applications,including optical isolators,delay lines,and lasers.However,the structures are complicated because an additional coupler ring between neighboring rings is needed to construct photonic pseudospin.A photonic anomalous Floquet topological insulator is proposed and experimentally demonstrated in the microwave regime.This improved design takes advantage of the efficient and backward coupling of negative-index media.The results contribute to the understanding of topological structures in metamaterials and point toward a unique direction for constructing useful topological photonic devices.

Review of the evolution and prevention of friction,wear,and noise for water-lubricated bearings used in ships

With the development of green tribology in the shipping industry,the application of water lubrication gradually replaces oil lubrication in stern bearings and thrust bearings.In terms of large-scale and high-speed ships,water-lubricated bearings with high performance are more strictly required.However,due to the lubricating medium,water-lubricated bearings have many problems such as friction,wear,vibration,noise,etc.This review focuses on the performance of marine water-lubricated bearings and their failure prevention mechanism.Furthermore,the research of marine water-lubricated bearings is reviewed by discussing its lubrication principle,test technology,friction and wear mechanism,and friction noise generation mechanism.The performance enhancement methods have been overviewed from structure optimization and material modification.Finally,the potential problems and the perspective of water-lubricated bearings are given in detail.

Greenhouse gas emissions from Daihai Lake,China:Should eutrophication and salinity promote carbon emission dynamics?

Greenhouse gases(GHGs)emitted or absorbed by lakes are an important component of the global carbon cycle.However,few studies have focused on the GHG dynamics of eutrophic saline lakes,thus preventing a comprehensive understanding of the carbon cycle.Here,we conducted four sampling analyses using a floating chamber in Daihai Lake,a eutrophication saline lake in Inner Mongolia Autonomous Region,China,to explore its carbon dioxide(CO_(2))and methane(CH_(4))emissions.The mean CO_(2)emission flux(FCO_(2))and CH_(4)emission flux(FCH_(4))were 17.54±14.54 mmol/m^(2)/day and 0.50±0.50 mmol/m^(2)/day,respectively.The results indicated that Daihai Lake was a source of CO_(2)and CH_(4),and GHG emissions exhibited temporal variability.The mean CO_(2)partial pressure(p CO_(2))and CH_(4)partial pressure(p CH_(4))were 561.35±109.59μatm and 17.02±13.45μatm,which were supersaturated relative to the atmosphere.The regression and correlation analysis showed that the main influencing factors of p CO_(2)were wind speed,dissolved oxygen(DO),total nitrogen(TN)and Chlorophyll a(Chl.a),whereas the main influencing factors of p CH_(4)were water temperature(WT),Chl.a,nitrate nitrogen(NO_(3)^(-)-N),TN,dissolved organic carbon(DOC)and water depth.Salinity regulated carbon mineralization and organic matter decomposition,and it was an important influencing factor of p CO_(2)and p CH_(4).Additionally,the trophic level index(TLI)significantly increased p CH_(4).Our study elucidated that salinity and eutrophication play an important role in the dynamic changes of GHG emissions.However,research on eutrophic saline lakes needs to be strengthened.

mIgM-mediated splenic marginal zone B cells targeting of folic acid for immunological evasion

Folic acid is a fully oxidized synthetic folate with high bioavailability and stability which has been extensively prescribed to prevent congenital disabilities.Here we revealed the immunosuppressive effect of folic acid by targeting splenic marginal zone B(MZB)cells.Folic acid demonstrates avid binding with the Fc domain of immunoglobulin M(IgM),targeting IgM positive MZB cells in vivo to destabilize IgM-B cell receptor(BCR)complex and block immune responses.The induced anergy of MZB cells by folic acid provides an immunological escaping window for antigens.Covalent conjugation of folic acid with therapeutic proteins and antibodies induces immunological evasion to mitigate the production of anti-drug antibodies,which is a major obstacle to the long-term treatment of biologics by reducing curative effects and/or causing adverse reactions.Folic acid acts as a safe and effective immunosuppressant via IgM-mediated MZB cells targeting to boost the clinical outcomes of biologics by inhibiting the production of anti-drug antibodies,and also holds the potential to treat other indications that adverse immune responses need to be transiently shut off.

A universal non-Hermitian platform for bound state in the continuum enhanced wireless power transfer

Non-Hermitian systems with parity–time(PT)-symmetry have been extensively studied and rapidly developed in resonance wireless power transfer(WPT).The WPT system that satisfies PT-symmetry always has real eigenvalues,which promote efficient energy transfer.However,meeting the condition of PT-symmetry is one of the most puzzling issues.Stable power transfer under different transmission conditions is also a great challenge.Bound state in the continuum(BIC)supporting extreme quality-factor mode provides an opportunity for efficient WPT.Here,we propose theoretically and demonstrate experimentally that BIC widely exists in resonance-coupled systems without PT-symmetry,and it can even realize more stable and efficient power transfer than PT-symmetric systems.Importantly,BIC for efficient WPT is universal and suitable in standard second-order and even high-order WPT systems.Our results not only extend non-Hermitian physics beyond PT-symmetry,but also bridge the gap between BIC and practical application engineering,such as highperformance WPT,wireless sensing and communications.

Observation of maximal intrinsic chirality empowered by dual quasi-bound states in the continuum in a planar metasurface

Metasurfaces with spin-selective transmission play an increasingly critical role in realizing optical chiral responses,especially for strong intrinsic chirality,which is limited to complex three-dimensional geometry.In this paper,we propose a planar metasurface capable of generating maximal intrinsic chirality and achieving dual-band spinselective transmission utilizing dual quasi-bound states in the continuum(quasi-BICs)caused by the structural symmetry breaking.Interestingly,the value of circular dichroism(CD)and the transmittance of two kinds of circular polarization states can be arbitrarily controlled by tuning the asymmetry parameter.Remarkable CD approaching unity with the maximum transmittance up to 0.95 is experimentally achieved in the dual band.Furthermore,assisted by chiral BICs,the application in polarization multiplexed near-field image display is also exhibited.Our work provides a new avenue to flexibly control intrinsic chirality in planar structure and offers an alternative strategy to develop chiral sensing,multiband spin-selective transmission,and high-performance circularly polarized wave detection.The basic principle and design method of our experiments in the microwave regime can be extended to other bands,such as the terahertz and infrared wavelengths.

Exceptional point empowered near-field routing of hyperbolic polaritons

Subwavelength-scale manipulation of electromagnetic waves forms the cornerstone of next-generation photonic devices and quantum information processing[1],where extensive efforts have focused on momentum-frequency dispersion through modification of the sizes,shape topology,and symmetry of the isofrequency contours(IFCs)[2,3].For instance,twisting of the multi-layers of stacked vdW materials results in a topological transition from open(hyperbolic-like)to closed(elliptical-like)IFCs(i.e.,control of the propagation wavefront).In contrast,the symmetry of IFCs,which is deeply rooted in the system symmetry,is more difficult to modulate[4].For example,hyperbolic polaritons exhibit four mirrorsymmetric beams in high-symmetry orthorhombic crystals,while asymmetric propagation of tilted hyperbolic shear polaritons only emerges in low-symmetry monoclinic crystals[3].

Observation of accurately designed bound states in the continuum in momentum space

Bound states in the continuum(BICs)in artificial photonic structures have received considerable attention since they offer unique methods for the extreme field localization and enhancement of light-matter interactions.Usually,the symmetry-protected BICs are located at high symmetric points,while the positions of accidental BICs achieved by tuning the parameters will appear at some points in momentum space.Up to now,to accurately design the position of the accidental BIC in momentum space is still a challenge.Here,we theoretically and experimentally demonstrate an accurately designed accidental BIC in a two-coupled-oscillator system consisting of bilayer gratings,where the optical response of each grating can be described by a single resonator model.By changing the interlayer distance between the gratings to tune the propagation phase shift related to wave vectors,the position of the accidental BIC can be arbitrarily controlled in momentum space.Moreover,we present a general method and rigorous numerical analyses for extracting the polarization vector fields to observe the topological properties of BICs from the polarization-resolved transmission spectra.Finally,an application of the highly efficient second harmonic generation assisted by quasi-BIC is demonstrated.Our work provides a straightforward strategy for manipulating BICs and studying their topological properties in momentum space.

Deep learning-based intelligent precise aeration strategy for factory recirculating aquaculture systems

Factory recirculating aquaculture system(RAS)is facing in a stage of continuous research and technological in-novation.Intelligent aquaculture is an important direction for the future development of aquaculture.However,the RAS nowdays still has poor self-learning and optimal decision-making capabilities,which leads to high aqua-culture cost and low running efficiency.In this paper,a precise aeration strategy based on deep learning is de-signed for improving the healthy growth of breeding objects.Firstly,the situation perception driven by computer vision is used to detect the hypoxia behavior.Then combined with the biological energy model,it is constructed to calculate the breeding objects oxygen consumption.Finally,the optimal adaptive aeration strategy is generated according to hypoxia behavior judgement and biological energy model.Experimental results show that the energy consumption of proposed precise aeration strategy decreased by 26.3%compared with the man-ual control and 12.8%compared with the threshold control.Meanwhile,stable water quality conditions acceler-ated breeding objects growth,and the breeding cycle with the average weight of 400 g was shortened from 5 to 6 months to 3–4 months.

Intelligent cache and buffer optimization for mobile VR adaptive transmission in 5G edge computing networks

Virtual Reality(VR)is a key industry for the development of the digital economy in the future.Mobile VR has advantages in terms of mobility,lightweight and cost-effectiveness,which has gradually become the mainstream implementation of VR.In this paper,a mobile VR video adaptive transmission mechanism based on intelligent caching and hierarchical buffering strategy in Mobile Edge Computing(MEC)-equipped 5G networks is proposed,aiming at the low latency requirements of mobile VR services and flexible buffer management for VR video adaptive transmission.To support VR content proactive caching and intelligent buffer management,users’behavioral similarity and head movement trajectory are jointly used for viewpoint prediction.The tile-based content is proactively cached in the MEC nodes based on the popularity of the VR content.Second,a hierarchical buffer-based adaptive update algorithm is presented,which jointly considers bandwidth,buffer,and predicted viewpoint status to update the tile chunk in client buffer.Then,according to the decomposition of the problem,the buffer update problem is modeled as an optimization problem,and the corresponding solution algorithms are presented.Finally,the simulation results show that the adaptive caching algorithm based on 5G intelligent edge and hierarchical buffer strategy can improve the user experience in the case of bandwidth fluctuations,and the proposed viewpoint prediction method can significantly improve the accuracy of viewpoint prediction by 15%.

STING signaling activation inhibits HBV replication and attenuates the severity of liver injury and HBV-induced fibrosis

The covalently closed circular DNA(cccDNA)of HBV plays a crucial role in viral persistence and is also a risk factor for developing HBV-induced diseases,including liver fibrosis.Stimulator of interferon genes(STING),a master regulator of DNA-mediated innate immune activation,is a potential therapeutic target for viral infection and virus-related diseases.In this study,agonist-induced STING signaling activation in macrophages was revealed to inhibit cccDNA-mediated transcription and HBV replication via epigenetic modification in hepatocytes.Notably,STING activation could efficiently attenuate the severity of liver injury and fibrosis in a chronic recombinant cccDNA(rcccDNA)mouse model,which is a proven suitable research platform for HBV-induced fibrosis.Mechanistically,STING-activated autophagic flux could suppress macrophage inflammasome activation,leading to the amelioration of liver injury and HBV-induced fibrosis.Overall,the activation of STING signaling could inhibit HBV replication through epigenetic suppression of cccDNA and alleviate HBV-induced liver fibrosis through the suppression of macrophage inflammasome activation by activating autophagic flux in a chronic HBV mouse model.This study suggests that targeting the STING signaling pathway may be an important therapeutic strategy to protect against persistent HBV replication and HBV-induced fibrosis.

Tribological behavior of co-textured cylinder liner-piston ring during running-in

The running-in of cylinder liner-piston rings(CLPRs)is the most important process that must be performed before a marine diesel engine can be operated.The quality of running-in directly affects the reliability of a CLPR.The surface texture of a CLPR has been proven to significantly affect its lubrication performance.In this study,the tribological behavior of a CLPR during running-in is investigated.Three types of surface textures are generated on the CLPR via laser processing:dimple texture on piston rings,groove texture on cylinder liners,and co-texture on both sides.Subsequently,a series of tests are performed on a slice tester.A load of 300 N(1.64 MPa) is applied,and two speeds(50 and 100 rpm)are adopted.The CLPR running-in quality is characterized based on three parameters,i.e.,the friction coefficient,contact resistance,and wear topography.Experimental results show that,compared with a non-textured surface,the three types of surface textures mentioned above improved the friction performance during running-in.The lubricant supply capacity of the dimple texture on the piston ring,as a mobile oil reservoir,is stronger than that of the groove texture on the cylinder liner serving as a static oil reservoir.By contrast,the wear resistance of the dimple texture,as a movable debris trap on the piston ring,is weaker than that of the groove texture on the cylinder liner,which serves as a static debris trap.It is demonstrated that the co-texture combines the advantages of dimples and groove textures.Compared with non-textured surfaces,the friction coefficient decreased the most at 100 rpm(44.5%),and the contact resistance improved the most at 50 rpm(352.9%).The coupling effect provides the surface with improved running-in quality by optimizing the tribological performance,particularly at the dead center.This study provides guidance for the tribological design and manufacturing of CLPR in marine diesel engines.

Designing soft/hard double network hydrogel microsphere/UHMWPE composites to promote water lubrication performance

Several soft tissues residing in the living body have excellent hydration lubrication properties and can provide effective protection during relative motion.In order to apply this advantage of soft matters in practical applications and try to avoid its disadvantage,such as swelling and weakening in water,a design strategy of a soft/hard double network(DN)hydrogel microsphere modified ultrahigh molecular weight polyethylene(UHMWPE)composite is proposed in this study.A series of microspheres of urea-formaldehyde(UF),polyacrylamide(PAAm)hydrogel,UF/PAAm double network,and their composites were prepared.The mechanical properties,swelling,wettability,friction properties,and the lubrication mechanisms of the composites were investigated.The results show that DN microspheres can have an excellent stability and provide hydration lubrication.The performance of 75 DN-1 composite was superior to others.This finding will provide a novel strategy for the development of water-lubricated materials and have wide application in engineering fields.