Theory and classification of mass extinction causationOA

Theory regarding the causation of mass extinctions is in need of systematization, which is the focus of this contribution. Every mass extinction has both an ultimate cause, i.e. the trigger that leads to various climato-environmental changes, and one or more proximate cause(s), i.e. the specific climato-environmental changes that result in elevated biotic mortality. With regard to ultimate causes, strong cases can be made that bolide(i.e. meteor) impacts, large igneous province(LIP) eruptions an...     

Photodegradable polar-functionalized polyethylenesOA

The degradation of plastics has attracted much attention from the global community.Polyethylenes(PEs),as the most abundant synthetic plastics,are most frequently studied.PE is non-degradable and non-polar because of the sole presence of the pure hydrocarbon components.Concurrent incorporation of both in-chain cleavable and functional groups into the PE chain is an effective pathway to overcome the non-degradable and non-polar issue;however,the method for achieving this pathway remains elusive.He...     

Graphene for gold extractionOA

<正>Gold is a unique element,characterized not only by limited,though still reasonable,availability (useful for monetary applications) but also for its rather unique properties useful for many industries [1]:chemical inertness,high electrical conductivity,plasticity,etc.As gold reserves in Earth’s crust diminish with traditional minings’urban mining’that recycles gold from gold-containing wastes (such as electronic waste,e-waste) has emerged as an important supply method for gold sustainabi...     

The heterogeneity-diversity-system performance nexusOA

Ever-growing human population and nutritional demands,supply chain disruptions,and advancing climate change have led to the re alization that changes in diversity and system performance are intimately linked.Moreover,diversity and system performance depend on heterogeneity.Mitigating changes in system performance and promoting sustainable living conditions requires transformative decisions.Here,we introduce the heterogeneity-diversity-system performance(HDP) nexus as the conceptual basis upon wh...     

Climbing robots for manufacturingOA

Robotized intelligent manufacturing is a growing trend in the manufacturing of large and complex components in aviation,aerospace,marine engineering and other industries.With their expansive workspaces and flexible deployment,climbing manufacturing robots can create a revolutionary manufacturing paradigm for large and complex components.This paper defines the climbing manufacturing robot based on the application status of climbing robots and then analyzes four key technical re quirements:adhesio...     

Microbes in mass extinction: an accomplice or a savior?OA

<正>Microbes include various types of organisms that are invisible to the naked eye,e.g. bacteria, archaea and microeukaryotes. Although the precise number remains largely unknown, microbes are recognized as the unseen majority of our biosphere [1]. As a group of organisms classified by body size, microbes cover a considerable spectrum of metabolisms,     

Van der Waals superlatticesOA

<正>Semiconductor technology has enabled many essential devices,including transistors for computing and communication,diodes for solid-state lighting and photovoltaics.Behind all these devices,the material foundation is a series of highly elaborated heterostructures and superlattices[1].To this end,integrating different materials into heterostructures or superlattices with well-defined spatial modulation of chemical compositions and electronic structures is central for generating designed e...     

Superscattering of water wavesOA

Inspired by the concept of superscattering in optics,we for the first time theoretically predict and experimentally demonstrate the superscattering phenomenon in water waves.The subwavelength superscatterer is constructed by multi-layered concentric cylinders with an inhomogeneous depth profile.The superscatterer breaks the long-held single-channel scattering limit by several times and thus significantly enhances the total scattering strength.The underlying mechanism originates from the near deg...     

Anthropogenic monoterpenes aggravating ozone pollutionOA

Monoterpenes have been known to have a critical influence on air quality and climate change through their impact on the formation of fine particles.Here we present field evidence that monoterpene oxidations largely enhanced local ozone production in a regional site in eastern China.The observed monoterpene was most likely from biomass burning rather than biogenic emissions,as indicated by the high correlation with CO at night-time,and the observed ratio of these two species was consistent with p...     

Competition on robust deep learningOA

<正>PROBLEM In recent years,the rapid development of artificial intelligence (AI) technology,especially machine learning and deep learning, is profoundly changing human production and lifestyle.In various fields,such as robotics,face recognition,autonomous driving and healthcare,AI is playing an important role.However,although AI is promoting the technological revolution and industrial progress,its security risks are often overlooked.Previous studies have found that the wellperforming deep ...     

Evolution of artificial ion channelsOA

<正>Protein ion channels on a cell membrane generate action potentials for cellular signal transduction, and regulate biological activities during life. Since the discovery of the asymmetric ion transport phenomenon in quartz nanopipettes by Bard and colleagues [1], synthetic nanofluidic materials and devices have attracted a lot of research interests from the scientific community,     

Organic semiconductor-incorporated two-dimensional halide perovskitesOA

<正>Recently,the search for novel two-dimensional (2D) organic-inorganic halide perovskite materials has come to a renaissance.There is significant interest not only in terms of their intriguing optoelectronic properties,but also their structural diversity and improved stability.The 2D perovskite structure can be visualized as atomically thin slabs cut from 3D parent structures along different crystal directions that are sandwiched between two layers of large organic cations.The bulky organ...     

Boosted on-chip energy storage with transistorsOA

<正>On-chip energy-storage devices play an important role in powering wireless environmental sensors and microelectrome chanical systems [1,2].Starting from the 1980s,on-chip energy-storage devices,including microbatteries and super capacitors,have been applied to power the real-time clock on a chip [3].These tiny batteries/supercapacitors enable the real-time clock to keep working when the electronics are off.In this way,electronic devices can be restarted with a valid time.With the develo...     

Revisiting non-linear Thomson scattering with metamaterialsOA

<正>Non-linear optics is a branch of optics that studies the intriguing and sometimes unexpected ways in which light and matter interact at high intensities, when the polarization density does not respond linearly to the electric field of the light. The pursuit of the perfect non-linear optical material has been ongoing ever since the pioneering experiment on second harmonic generation carried out by Franken in 1961 [1]. Indeed,     

New progress in zeolite synthesis and catalysisOA

The rational design synthesis of zeolite catalysts with effective,environmentally benign and atom-economic routes is a major topic in the field of microporous materials,as it would avoid the high labor cost and inefficiency of traditional trial-and-error methods in developing new structures and dispel environmental concerns regarding the industrial mass production of zeolites.Catalytic applications of zeolite materials have expanded from conventional single functionalities,such as solid acids or...     

Acoustic fabrics enabled by piezoelectric polymer fibersOA

<正>Some 15 years ago,Prof.Yoel Fink at MIT inspired the world by proposing multimaterial fibers that can see,hear,sense and communicate [1] by integrating microelectronic devices into single thermally drawn fiber or fiber assembly.Since then,great progress has been made around the globe [2] to impart these functions into fabrics with such fiber-based devices.     

Photonic orbital angular momentum with controllable orientationOA

Vortices are whirling disturbances,commonly found in nature,ranging from tremendously small scales in Bose-Einstein condensations to cosmologically colossal scales in spiral galaxies.An optical vortex,generally associated with a spiral phase,can carry orbital angular momentum(OAM).The optical OAM can either be in the longitudinal direction if the spiral phase twists in the spatial domain or in the transverse direction if the phase rotates in the spatiotemporal domain.In this article,we demonstra...