Tailoring spatiotemporal dynamics of plasmonic vortices

Plasmonic vortices confining orbital angular momentums to surface have aroused wide research interest in the last decade.Recent advances of near-field microscopes have enabled the study on the spatiotemporal dynamics of plasmonic vortices,providing a better understanding of optical orbital angular momentums in the evanescent wave regime.However,these works only focused on the objective characterization of plasmonic vortex and have not achieved subjectively tailoring of its spatiotemporal dynamics for specific applications.Herein,it is demonstrated that the plasmonic vortices with the same topological charge can be endowed with distinct spatiotemporal dynamics by simply changing the coupler design.Based on a near-field scanning terahertz microscopy,the surface plasmon fields are directly obtained with ultrahigh spatiotemporal resolution,experimentally exhibiting the generation and evolution divergences during the whole lifetime of plasmonic vortices.The proposed strategy is straightforward and universal,which can be readily applied into visible or infrared frequencies,facilitating the development of plasmonic vortex related researches and applications.

Regulating the growth of lithium dendrite by coating an ultra-thin layer of gold on separator for improving the fast-charging ability of graphite anode

With the ever-growing application of lithium-ion batteries(LIBs), their fast-charging technology has attracted great interests of scientists. However, growth of lithium dendrites during fast charge of the bat teries with high energy density may pose great threats to the operation and cause serious safety issues Herein, we prepared a functional separator with an ultra-thin(20 nm) layer of Au nanoparticles deposited by evaporation coating method which could regulate growth direction and morphology of the lithium dendrites, owing to nearly zero overpotential of lithium meal nucleation on lithiated Au. Once the Li den drites are about to form on the graphite anode during fast charging(or lithiation), they plate predomi nantly on the Au deposited separator rather than on the graphite. Such selective deposition does no compromise the electrochemical performance of batteries under normal cycling. More importantly, i enables the better cycling stability of batteries at fast charge condition. The Li/Graphite cells with Au nanoparticles coated separator could cycle stably with a high areal capacity retention of 90.5% over 95 cycles at the current density of 0.72 m A cm^(-2). The functional separator provides an effective strategy to adjust lithium plating position at fast charge to ensure high safety of batteries without a compromise on the energy density of LIBs.

Anti-Attacking Modeling and Analysis of Cyberspace Mimic DNS

With the rapid development of information technology,the cyberspace security problem is increasingly serious.Kinds of dynamic defense technology have emerged such as moving target defense and mimic defense.This paper aims to describe the architecture and analyze the performance of Cyberspace Mimic DNS based on generalized stochastic Petri net.We propose a general method of anti-attacking analysis.For general attack and special attack model,the available probability,escaped probability and nonspecial awareness probability are adopted to quantitatively analyze the system performance.And we expand the GSPN model to adjust to engineering practice by specifying randomness of different output vectors.The result shows that the proposed method is effective,and Mimic system has high anti-attacking performance.To deal with the special attack,we can integrate the traditional defense mechanism in engineering practice.Besides,we analyze the performance of mimic DNSframework based on multi-ruling proxy and input-output desperation,the results represent we can use multi ruling or high-speed cache servers to achieve the consistent cost of delay,throughput compared with single authorized DNS,it can effectively solve 10%to 20%performance loss caused by general ruling proxy.

Active-Thermal-Tunable Terahertz Absorber with Temperature-Sensitive Material Thin Film

It is shown that active-tunable terahertz absorbers can be realized in a sandwich-structured system comprising an ultrathin dielectric film(polyimide) on a temperature-sensitive substrate(InSb) with a metal film on the back by utilizing the intrinsic carrier density(N) variation in InSb. When increasing the temperature from 250 to 320 K, N in InSb varied from ～5.50×1015 to ～2.98×1016 cm–3. Fixing the thickness of dielectric film with the value of 1.37 μm, the absorption peak shifted from 1.41 to 3.29 THz while keeping absorption higher than 99%. This active tunability can respond to even a slight temperature perturbation, and shows polarization insensitivity as well as high tolerance of incidence-angle(absorption peak can still exceed 90% even the incidence angle reaches 60°). Besides, the refractive index of polyimide(PI) has thermal stability at the terahertz range and the merit of good workability. These characteristics guarantee the stability of activetunable performance. The peculiarities and innovations of this proposal promise a wide range of high efficiency terahertz devices, such as thermal sensors, spatial light modulators(SLMs) and so on.

Decoherence of fiber light sources using a single-trench fiber

Decoherence of fiber laser sources is of great importance in imaging applications,and most current studies use ordinary multi-mode fibers(MMFs).Here,a newly designed single-trench fiber(STF)is investigated to reduce the spatial coherence of fiber light source and compared with MMFs.By bending two fibers with different turns,speckle contrast of a 0.8-m-long STF can be reduced from 0.13 to 0.08,while a 0.8-m-long MMF shows an inverse result.Through speckle contrast and decoupling-mode analysis,the reason of this inverse trend is revealed.Firstly,the STF supports more modes than the MMF due to its larger core diameter.Secondly,mode leak from the first core of the STF can couple to the second core when bending the STF.Thus,power distribution among high and low-order modes become more even,reducing the spatial coherence considerably.However,in the MMF,high-order modes become leaky modes and decrease slightly when bending the fiber.This work provides a new method to modulate coherence of light source and a new angle to study decoherence principle using special fibers.

Path Exploration and Countermeasure Innovation for Developing Circular Agriculture in Southeast China

This paper firstly elaborated current situation of agricultural resources and ecological environment protection of China,and pointed out that circular agriculture is an inevitable choice for sustainable development of agriculture and effective approach for low-carbon economic development. Then,it analyzed mode and benefit of typical circular agriculture,such as ecological orchard in southeast hills,sightseeing ecological agricultural garden,and crop straw use. Finally,it came up with countermeasures for further developing circular agriculture,including integrating building system and establishing suitable mode,formulating production standard and ensuring food safety,strengthening technological innovation,and supporting sustainable development.

Trial of Intensive Blood-Pressure Control in Older Patients with Hypertension

Results:Of the 9624 patients screened for eligibility,8511 were enrolled in the trial;4243 were randomly assigned to the intensive-treatment group and 4268 to the standard-treatment group.At 1 year of follow-up,the mean systolic blood pressure was 127.5 mm Hg in the intensive-treatment group and 135.3 mm Hg in the standard-treatment group.During a median follow-up period of 3.34 years,primary-outcome events occurred in 147 patients(3.5%)in the intensive-treatment group,as compared with 196 patients(4.6%)in the standard-treatment group(hazard ratio,0.74;95%confidence interval[CI],0.60 to 0.92;P=0.007).The results for most of the individual components of the primary outcome also favored intensive treatment:the hazard ratio for stroke was 0.67(95%CI,0.47 to 0.97),acute coronary syndrome 0.67(95%CI,0.47 to 0.94).

The associations between telomere trajectory and blood pressure change in a longitudinal hypertensive cohort in China

Objective Telomere length, as an emerging marker of biological age,isrelatedwithhypertension.Ouraimistoinvestigatethe relationship between telomere trajectory and blood pressure change as well as the incident cardiovascular events in a longitudinal hypertensive cohort in China.

Long-term stimulation of angiotensin Ⅱ induced endothelial senescence and dysfunction

Objective Vascular endothelial cells senescence is one of major risk factors for atherosclerotic diseases,which can be induced by endogenous peptides,such as angiotensin Ⅱ(Ang Ⅱ).However,the effect of chronic Ang Ⅱ stimulation on endothelial senescence remains unknown.Therefore,this study aims to investigate the changes in morphology and function of human umbilical vein endothelial cells(HUVECs)in response to the chronic stimulation of Ang Ⅱ.

Exciton-polariton based WS_(2)polarization modulator controlled by optical Stark beam

The recent era of fast optical manipulation and optical devices owe a lot to exciton-polaritons being lighter in mass,faster in speed and stronger in nonlinearity due to hybrid light-matter characteristics.The room temperature existence of polaritons in two dimensional materials opens up new avenues to the design and analysis of all optical devices and has gained the researchers attention.Here,spin-selective optical Stark effect is introduced to form a waveguide effect in uniform community of polaritons,and is used to realize polarization modulation of polaritons.The proposed device basically takes advantage of the spin-sensitive properties of optical Stark effect of polaritons inside the WS_(2)microcavity so as to guide different modes and modulate polarization of polaritons.It is shown that polaritonic wavepacket of different mode profiles can be generated by changing intensity of the optical Stark beam and the polarization of polaritons can be controlled and changed periodically along the formed waveguide by introduction birefringence that is sensitive to polarization degree of the optical Stark beam.

Development Trend Analysis of Computer Management Information System

Based on the retrospect and analysis of the main points of the development of computer management information system,on the basis of the study of relevant data such as enterprise units,mass media,personal information and information security,and according to the actual situation of our country,this paper intentionally and systematically collects relevant research materials on the role of management information system in the survival and development of enterprises,and aims at one or more merits.To study its impact,this paper focuses on three aspects:application analysis,development direction and implementation strategy,which can provide strong reference and guidance for the application of enterprise computer management system.

Research on the Development and Application of Campus Card in Colleges and Universities

With the rapid development of the construction of smart campus in Colleges and universities and the maturity of related technologies,campus card has become the most frequently used and the most frequently used core component of smart campus.Based on the actual construction of onecard system in domestic universities and the author’s years of experience in campus card management,this paper makes a systematic study on the development of campus card,virtual campus card,big data application,information security and other aspects,with a view to providing effective reference for the construction of campus card in Colleges and universities.

Active terahertz beam steering based on mechanical deformation of liquid crystal elastomer metasurface

Active metasurfaces are emerging as the core of next-generation optical devices with their tunable optical responses and flat-compact topography.Especially for the terahertz band,active metasurfaces have been developed as fascinating devices for optical chopping and compressive sensing imaging.However,performance regulation by changing the dielectric parameters of the integrated functional materials exhibits severe limitations and parasitic losses.Here,we introduce a C-shape-split-ring-based phase discontinuity metasurface with liquid crystal elastomer as the substrate for infrared modulation of terahertz wavefront.Line-focused infrared light is applied to manipulate the deflection of the liquid crystal elastomer substrate,enabling controllable and broadband wavefront steering with a maximum output angle change of 22°at 0.68THz.Heating as another control method is also investigated and compared with infrared control.We further demonstrate the performance of liquid crystal elastomer metasurface as a beam steerer,frequency modulator,and tunable beam splitter,which are highly desired in terahertz wireless communication and imaging systems.The proposed scheme demonstrates the promising prospects of mechanically deformable metasurfaces,thereby paving the path for the development of reconfigurable metasurfaces.

Spectrally programmable Raman fiber laser with adaptive wavefront shaping

Raman fiber lasers(RFLs)have broadband tunability due to cascaded stimulated Raman scattering,providing extensive degrees of freedom for spectral manipulation.However,the spectral diversity of RFLs depends mainly on the wavelength flexibility of the pump,which limits the application of RFLs.Here,a spectrally programmable RFL is developed based on two-dimensional spatial-to-spectral mapping of light in multimode fibers(MMFs).Using an intracavity wavefront shaping method combined with genetic algorithm optimization,we launch light with a selected wavelength(s)at MMF output into the active part of the laser for amplification.In contrast,the light of undesired wavelengths is blocked.We demonstrate spectral shaping of the high-order RFL,including a continuously tunable single wavelength and multiple wavelengths with a designed spectral shape.Due to the simultaneous control of different wavelength regions,each order of Raman Stokes light allows flexible and independent spectral manipulation.Our research exploits light manipulation in a fiber platform with multieigenmodes and nonlinear gain,mapping spatial control to the spectral domain and extending linear light control in MMFs to active light emission,which is of great significance for applications of RFLs in optical imaging,sensing,and spectroscopy.

Generating superposed terahertz perfect vortices via a spin-multiplexed all-dielectric metasurface

Perfect optical vortices(POVs),characterized as a ring radius independent of topological charge(TC),possess extensive application in particle manipulation and optical communication.At present,the complex and bulky optical device for generating POVs has been miniaturized by leveraging the metasurface,and either spindependent or spin-independent POV conversions have been further accomplished.Nevertheless,it is still challenging to generate superposed POVs for incidences with orthogonal circular polarization.Here,a spinmultiplexed all-dielectric metasurface method for generating superposed POVs in the terahertz frequency range is proposed and demonstrated.By using the multiple meta-atom comprised structure as the basic unit,the complex amplitude of two superposed POVs is modulated,decoupled,and subsequently encoded to left-and righthanded circular polarization incidences.Furthermore,two kinds of metasurfaces are fabricated and characterized to validate this controlling method.It is demonstrated that the measured intensity and phase distributions match well with the calculation of the Rayleigh–Sommerfeld diffraction integral,and the radius of superposed POVs is independent of TCs.This work provides promising opportunities for developing ultracompact terahertz functional devices applied to complex structured light generation and terahertz communication,and exploring sophisticated spin angular momentum and orbital angular momentum interactions like the photonic spin-Hall effect.

Meta-optics inspired surface plasmon devices

Surface plasmons(SPs)are electromagnetic surface waves that propagate at the interface between a conductor and a dielectric.Due to their unique ability to concentrate light on two-dimensional platforms and produce very high local-field intensity,SPs have rapidly fueled a variety of fundamental advances and practical applications.In parallel,the development of metamaterials and metasurfaces has rapidly revolutionized the design concepts of traditional optical devices,fostering the exciting field of meta-optics.This review focuses on recent progress of meta-optics inspired SP devices,which are implemented by the careful design of subwavelength structures and the arrangement of their spatial distributions.Devices of general interest,including coupling devices,on-chip tailoring devices,and decoupling devices,as well as nascent SP applications empowered by sophisticated usage of meta-optics,are introduced and discussed.

High-voltage,low-temperature supercapacitors enabled by localized“water-in-pyrrolidinium chloride”electrolyte

Aqueous electrolytes offer superior prospects for advanced energy storage.“Water-in-salt”(WIS)electrolytes exhibit a wide electrochemical stability window(ESW),but their low conductivity,high viscosity,and precipitation at low temperatures restrict their application.Herein,we report a novel localized“water-in-pyrrolidinium chloride”electrolyte(LWIP;1 mol/L,N-propyl-N-methylpyrrolidinium chloride/(water and N,Ndimethylformamide,1:4 by molality))enabling high-voltage,low-temperature supercapacitors(SCs).The greatly improved ESW(3.451 V)is mainly attributed to the strong solvation between Cl-and water molecules,which broadens the negative stability.This water-binding mechanism is very different from that of a WIS electrolyte based on alkali metal salt.SCs using LWIP electrolytes not only yield a high operating voltage of 2.4 V and excellent capacity retention(82.8%after 15,000 cycles at 5 A g^(-1))but also operate stably at-20℃.This work provides new approaches for the design and preparation of novel electrolytes.

INTERACTIVE KNOWLEDGE LEARNING BY ARTIFICIAL INTELLIGENCE FOR SMALLHOLDERS

Enhancement of farming management relies heavily on enhancing farmer knowledge.In the past,both the direct learning approach and the personnel extension system for improving fertilization practices of smallholders has proven insufficiently effective.Therefore,this article proposes an interactive knowledge learning approach using artificial intelligence as a promising alternative.The system consists of two parts.The first is a dialog interface that accepts information from farmers about their current farming practices.The second part is an intelligent decision system,which categorizes the information provided by farmers in two categories.The first consists of onfarm constraints,such as fertilizer resources,split application times and seasons.The second comprises knowledge-based practices by farmers,such as nutrient in-and output balance,ratios of different nutrients and the ratios of each split nutrient amount to the total nutrient input.The interactive knowledge learning approach aims to identify and rectify incorrect practices in the knowledge-based category while considering the farmer's available finance,labor,and fertilizer resources.Investigations show that the interactive knowledge learning approach can make a strong contribution to prevention of the overuse of nitrogen and phosphorus fertilizers,and mitigating agricultural non-point sourcepollution.

Composition and Functional Capacity of Gut Microbes are Associated with Arterial Stiffness:A Prospective Study

Objective:Arterial stiffness is an important predictor of cardiovascular disease.Microbial diversity in the gut has been shown to be associated inversely with arterial stiffness in Caucasian populations.However,due to the different profiles of the gut microbiota among ethnicities,the relationship between gut-microbiota dysbiosis and the progression of arterial stiffness merits further investigation.This study aimed to investigate the association between the composition and functional capacity of the gut microbiota and the progression of arterial stiffness.Methods:“Shotgun”metagenomics sequencing were undertaken in 96 individuals from a hypertension-associated gut-microbiota study in the Kailuan cohort,who measured brachial-ankle pulse wave velocity(baPWV)and provided fecal samples between September 2014 and February 2015 at Kailuan General Hospital and 11 affiliated hospitals.The different composition and functional capacity of the gut microbiota were compared between individuals without arterial stiffness(normal arterial stiffness group,baPWV<1,400 cm/s,n=27)and participants with arterial stiffness(increased arterial stiffness group,baPWV≥1,400 cm/s,n=69)at baseline.These participants were followed up prospectively for a mean duration of 2.6 years,and 50 underwent a repeat baPWV measurement.Associations between the gut microbiota and severity and progression of arterial stiffness were assessed using MaAsLin2 software after adjustment for age,sex,and mean arterial blood pressure and correction for multiple testing.Gene“catalogs”were aligned to the Kyoto Encyclopedia of Genes and Genomes(KEGG)database to obtain information for potential functional capacities of the gut microbiota.Results:In this study,14 genera and 50 species of bacteria were identified to be abundant in participants with normal arterial stiffness compared with those with increased arterial stiffness.Of 14 genera,the prevalence of beneficial bacteria of the genera Leadbetterella and Cytophaga was correlated inversely with baPWV(P<0.05).Analyses of functional capacity revealed gut-microbial dysfunctions in the synthetic processes of“threonine dehydratase”“hypothetical protein”“mannosyl transferase”and“type-IV secretion-system proteins”in individuals suffering from arterial stiffness.During follow-up,bacteria of the proinflammatory genera Escherichia,Shigella,and Ruegeria were enriched in individuals with increased baPWV.Functional analyses showed that 26 KEGG orthologs of gut microbes were associated with an increase in baPWV and involved in“carbohydrate metabolism”“amino acid metabolism”and“protein families related to genetic information processing.”Conclusions:The composition and functional capacity of the microbial community in the gut of people suffering from arterial stiffness differed from those in individuals not suffering from arterial stiffness.Our data provide a new direction for the causality of the host-gut microbiota in arterial stiffness.

嗅神经母细胞瘤术后放疗致鼻泪管狭窄一例

患者,女,37岁,因"右侧鼻塞、脓涕、嗅觉减退1年"于2016年10月31日到北京大学深圳医院(以下简称我院)耳鼻喉科就诊,查鼻窦CT提示:右侧上、中鼻道内占位性病变,符合嗅母细胞瘤改变。2016年11月4日在我院耳鼻喉科住院并在全身麻醉下行右侧经鼻鼻腔鼻窦肿瘤切除术,术后病理提示:右侧嗅神经母细胞瘤。