An intelligent prediction model of epidemic characters based on multi-feature

The epidemic characters of Omicron(e.g.large-scale transmission)are significantly different from the initial variants of COVID-19.The data generated by large-scale transmission is important to predict the trend of epidemic characters.However,the re-sults of current prediction models are inaccurate since they are not closely combined with the actual situation of Omicron transmission.In consequence,these inaccurate results have negative impacts on the process of the manufacturing and the service industry,for example,the production of masks and the recovery of the tourism industry.The authors have studied the epidemic characters in two ways,that is,investigation and prediction.First,a large amount of data is collected by utilising the Baidu index and conduct questionnaire survey concerning epidemic characters.Second,theβ-SEIDR model is established,where the population is classified as Susceptible,Exposed,Infected,Dead andβ-Recovered persons,to intelligently predict the epidemic characters of COVID-19.Note thatβ-Recovered persons denote that the Recovered persons may become Sus-ceptible persons with probabilityβ.The simulation results show that the model can accurately predict the epidemic characters.

Defects‑Rich Heterostructures Trigger Strong Polarization Coupling in Sulfides/Carbon Composites with Robust Electromagnetic Wave Absorption

Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic dissipation.Conventional methods,however,constrain their delicate constructions.Herein,an innovative alternative is proposed:carrageenan-assistant cations-regulated(CACR)strategy,which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon matrix.This unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction,benefiting the delicate construction of defects-rich heterostructures in M_(x)S_(y)/carbon composites(M-CAs).Impressively,these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and,simultaneously,induct local asymmetry of electronic structure to evoke large dipole moment,ultimately leading to polarization coupling,i.e.,defect-type interfacial polarization.Such“Janus effect”(Janus effect means versatility,as in the Greek two-headed Janus)of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first time.Consequently,the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm,compared to sulfur vacancies-free CAs without any dielectric response.Harnessing defects-rich heterostructures,this one-pot CACR strategy may steer the design and development of advanced nanomaterials,boosting functionality across diverse application domains beyond electromagnetic response.

硬段结构对含二硫键自修复聚氨酯性能的影响

硬段结构的研究对指导制备兼顾力学性能与自修复性能的聚氨酯弹性体具有重要的意义。文中分别以4,4'-二苯基甲烷二异氰酸酯(MDI)、4,4'-二环己基甲烷二异氰酸酯(HMDI)、甲苯二异氰酸酯(TDI)、异佛尔酮二异氰酸酯(IPDI)及双(2-羟基乙基)二硫醚(HEDS)为硬段部分,聚己内酯二元醇为软段部分,制备了一系列含脂肪族二硫键的自修复聚氨酯,探究了不同异氰酸酯、硬段含量和扩链剂对其力学性能与自修复性能的影响。结果表明,对于异氰酸酯结构来讲,脂环族异氰酸酯制备的自修复聚氨酯具备更好的力学性能与自修复性能;对于脂环族异氰酸酯体系聚氨酯的硬段含量而言,一定范围越高,二硫键与氢键的含量也越高,越有利于材料的力学性能与自修复性能;对于扩链剂结构来讲,脂肪族二硫键主要是促进较高温度条件下的自修复性能,对于室温自修复性能起到的作用有限。

低品质/低活性原材料在现代混凝土中的应用技术

针对低品质/低活性原材料难以利用的实际情况,打破了传统使用高品质/高活性原材料制备现代混凝土的限制,研发了利用低品质/低活性原材料制备现代混凝土的新工艺和新技术。通过实验室研究和现场试验,提出一整套具有针对性的技术方案如高性能混凝土、大体积混凝土、防腐蚀混凝土、超低强度充填混凝土,并在国内外多个重点工程成功应用。

Effects of runner design and pressurization on the microstructure of a high-pressure die cast Mg-3.0Nd-0.3Zn-0.6Zr alloy

To clarify the relationship between externally solidified crystals(ESCs)and other defects,e.g.,defect bands and pores,two dimensional(2D)and three dimensional(3D)characterization methods were adopted to analyze castings produced using a modified ingate system equipped with and without an ESC collector.The reduction of ESCs strongly reduced defect band width and shrinkage pore quantity.By reducing the quantity and size of ESCs,net-shrinkage pores were transformed into isolated island-shrinkage pores.We determined via statistical analysis that the mechanical properties of high pressure die castings were strongly related to the size and fraction of the ESCs rather than porosity volume.The reduction of ESCs also caused tensile transgranular fracture modes to transform into intergranular fracture modes.Additionally,casting pressurization strongly reduced pore morphology,volume,and size.

Seasonal variation of atmospheric coupling with oceanic mesoscale eddies in the North Pacific Subtropical Countercurrent

This study investigated the seasonal variation in the atmospheric response to oceanic mesoscale eddies in the North Pacific Subtropical Countercurrent(STCC)and its mechanism,based on satellite altimetric and reanalysis datasets.Although mesoscale eddy in the study area is more active in summer,the sea surface temperature(SST)anomaly associated with mesoscale eddies is more intense and dipolar in winter,which is largely due to the larger background SST gradient.Similarly,the impact of the oceanic eddy on sea surface wind speed and heat flux is strongest in winter,whereas its effect on precipitation rate is more significant in summer.The study revealed that the SST gradient in STCC could impact the atmosphere layer by up to 800 h Pa(900 h Pa)in boreal winter(summer)through the dominant vertical mixing mechanism.Moreover,the intensity of the SST gradient causes such seasonal variation in mesoscale air-sea coupling in the study region.In brief,a stronger(weaker)background SST gradient field in wintertime(summertime)leads to a larger(smaller)eddy-induced SST anomaly,thus differently impacting atmosphere instability and transitional kinetic energy flux over oceanic eddies,leading to seasonal variation in mesoscale air-sea coupling intensity.

l-凸Legendre曲线的曲率积分不等式

本文主要研究平面l-凸Legendre曲线,它是严格凸曲线的自然推广.本文一方面运用Green和Osher的方法,获得了l-凸Legendre曲线的Green-Osher不等式等号成立的充要条件,即当F(x)为R上的严格凸函数时,等号成立当且仅当曲线γ为圆周.另一方面结合获得的定理,得到了一系列关于l-凸Legendre曲线的曲率积分不等式.特别地,当γ为严格凸曲线时,所获推论为Ros不等式、Green-Osher不等式、Gage等周不等式的改进形式.

Realizing simultaneously excellent energy storage and discharge properties in AgNbO_(3)based antiferroelectric ceramics via La^(3t)and Ta^(5+)co-substitution strategy

AgNbO_(3)based antiferroelectric(AFE)ceramics have large maximum polarization and low remanent polarization,and thus are important candidates for fabricating dielectric capacitors.However,their energy storage performances have been still large difference with those of lead-based AFEs because of their room-temperature ferrielectric(FIE)behavior.In this study,novel La^(3+)and Ta^(5+)co-substituted AgNbO_(3)ceramics are designed and developed.The introduction of La^(3+)and Ta^(5+)decreases the tolerance factor,reduces the polarizability of B-site cations and increases local structure heterogeneity of AgNbO_(3),which enhance AFE phase stability and refine polarization-electric field(PeE)loops.Besides,adding La^(3+)and Ta^(5+)into AgNbO_(3)ceramics causes the decrease of the grain sizes and the increase of the band gap,which contribute to increased Eb.As a consequence,a high recoverable energy density of 6.79 J/cm3 and large efficiency of 82.1%,which exceed those of many recently reported AgNbO_(3)based ceramics in terms of overall energy storage properties,are obtained in(Ag0.88La0.04)(Nb0.96Ta0.04)O_(3)ceramics.Furthermore,the discharge properties of the ceramic with discharge time of 16 ns and power density of 145.03 MW/cm3 outperform those of many lead-free dielectric ceramics.

Unlocking the secrets of the invisible world:incredible deep optical imaging through in-silico clearing

In-silico clearing enables deep optical imaging of biological samples by correcting image blur caused by scattering and aberration.This breakthrough method offers researchers unprecedented insights into three-dimensional biological systems,with enormous potential for advancing biology and medicine to better understand living organisms and human health.

还原-氧化协同降解全/多卤代有机污染物

全/多卤代有机污染物大多具有生态毒性、生物蓄积性、环境持久性及长距离迁移性,不仅危害环境与生态安全,而且可经食物链传递威胁人类健康。由于卤原子是吸电子基团且取代数目多,这类物质的最高占据分子轨道能较低,难于被氧化降解,相反较易被还原法脱卤降解。随卤原子取代数减少,脱卤产物难被进一步还原,而其毒性甚至高于母体污染物。注意到低卤代有机物更容易发生氧化降解,一些研究构建了还原-氧化接力降解体系,即先利用还原法将全/多卤代有机污染物还原为低卤代产物,再利用氧化法降解这些中间产物,从而实现深度/完全脱卤和矿化。本文根据催化反应类型对还原-氧化联用法进行了归纳,分类介绍了基于传统化学催化、光催化、电化学、光电化学及机械化学等构建还原-氧化协同降解体系的原理及应用,以期为开发高效的处置技术提供思路和建议。

全球变化下海岸带微生物生态研究进展

海岸带地区是元素循环最活跃的自然区域之一,微生物作为地球元素循环的主要驱动者,对该区域生态系统中物质转化与能量流动起着至关重要的作用。本文从典型海岸带生态系统:海岸带湿地、海草床与海藻森林、近岸水体出发,围绕微生物参与的碳、氮循环过程以及其中的温室气体排放情况,综述了在全球气候变化与人为活动干扰的作用下,海岸带地区的微生物群落对外界环境变化的响应机制以及生态功能维持机制,最后对海岸带系统中微生物生态研究进行了初步的展望。

Radiation theory comparison for magnetoacoustic tomography with magnetic induction(MAT-MI)

Based on the principle of Lorentz force induced acoustic vibration, radiation theory comparison between acoustic point and dipole sources was conducted for magnetoacoustic tomography with magnetic induction(MAT-MI). It is proved that each acoustic source of MATMI is produced by the divergence of the magnetically induced Lorentz force, and the detected acoustic pressure is the integral of all diffraction sources inside the object.Wave clusters are produced by abrupt pressure changes at conductivity boundaries, and only the configurations in terms of shape and size of phantom models can be reconstructed. However, different from point source, positive and negative pressures are generated by the radiation pattern of dipole sources. Reverse vibration phases of wave clusters in collected waveforms and opposite polarities of borderline stripes in reconstructed images are produced at conductivity boundaries, representing the direction of conductivity changes. The experimentally collected waveforms and reconstructed images of the aluminum foil cylinder and cylindrical saline gel phantom model agree well with simulated results. The favorable results prove the validity of the radiation theory of acoustic dipole source and provide basis for further investigation of conductivity reconstruction for MAT-MI.

Ultrafast imaging for uncovering laser–material interaction dynamics

The physical mechanism of the dynamics in laser–material interaction has been an important research area.In addition to theoretical analysis,direct imaging‐based observation of ultrafast dynamic processes is an important approach to understand many fundamental issues in laser–material interaction such as inertial confinement fusion(ICF),laser accelerator construction,and advanced laser production.In this review,the principles and applications of three types of commonly used ultrafast imaging methods are introduced,including the pump–probe,X‐ray diagnosis,and single‐shot optical burst imaging.We focus on the technical features such as the spatial and temporal resolution for each technique,and present several conventional applications.

Social and Behavioral Determinants of Health in the Era of Artificial Intelligence with Electronic Health Records:A Scoping Review

Background.There is growing evidence that social and behavioral determinants of health(SBDH)play a substantial effect in a wide range of health outcomes.Electronic health records(EHRs)have been widely employed to conduct observational studies in the age of artificial intelligence(AI).However,there has been limited review into how to make the most of SBDH information from EHRs using AI approaches.Methods.A systematic search was conducted in six databases to find relevant peer-reviewed publications that had recently been published.Relevance was determined by screening and evaluating the articles.Based on selected relevant studies,a methodological analysis of AI algorithms leveraging SBDH information in EHR data was provided.Results.Our synthesis was driven by an analysis of SBDH categories,the relationship between SBDH and healthcare-related statuses,natural language processing(NLP)approaches for extracting SBDH from clinical notes,and predictive models using SBDH for health outcomes.Discussion.The associations between SBDH and health outcomes are complicated and diverse;several pathways may be involved.Using NLP technology to support the extraction of SBDH and other clinical ideas simplifies the identification and extraction of essential concepts from clinical data,efficiently unlocks unstructured data,and aids in the resolution of unstructured data-related issues.Conclusion.Despite known associations between SBDH and diseases,SBDH factors are rarely investigated as interventions to improve patient outcomes.Gaining knowledge about SBDH and how SBDH data can be collected from EHRs using NLP approaches and predictive models improves the chances of influencing health policy change for patient wellness,ultimately promoting health and health equity.