Inverse design and realization of an optical cavity-based displacement transducer with arbitrary responses

Optical cavity has long been critical for a variety of applications ranging from precise measurement to spectral analysis.A number of theories and methods have been successful in describing the optical response of a stratified optical cavity,while the inverse problem,especially the inverse design of a displacement sensitive cavity,remains a significant challenge due to the cost of computation and comprehensive performance requirements.This paper reports a novel inverse design methodology combining the characteristic matrix method,mixed-discrete variables optimization algorithm,and Monte Carlo method-based tolerance analysis.The material characteristics are indexed to enable the mixed-discrete variables optimization,which yields considerable speed and efficiency improvements.This method allows arbitrary response adjustment with technical feasibility and gives a glimpse into the analytical characterization of the optical response.Two entirely different light-displacement responses,including an asymmetric sawtooth-like response and a highly symmetric response,are dug out and experimentally achieved,which fully confirms the validity of the method.The compact Fabry-Perot cavities have a good balance between performance and feasibility,making them promising candidates for displacement transducers.More importantly,the proposed inverse design paves the way for a universal design of optical cavities,or even nanophotonic devices.

Hollow Co_(9)S_(8) cores encapsulated in hierarchical MXene@Bi_(2)O_(3) multiple shells for constructing binder-free electrodes of foldable supercapacitors

Rational structure design and regulation are of paramount importance for obtaining electrode materials with desirable electrochemical performance.Here,a novel binder-free electrode with the hollow Co_(9)S_(8) core@multi-shell structure(CS-x@MXene@Bi_(2)O_(3))derived from metal-organic frameworks(MOFs)precursor is well designed by the electrospinning,sulfuration,carbonization,and hydrothermal processes.In this architecture,the concentration of Co_(9)S_(8)(CS-x)is optimized for an ideal flexible substrate,which alleviates the dimensional variation for long cycle life.The unique cores and the MXene flakes engineered by Bi_(2)O_(3) multiple shells can be responsible for the superior characteristics,including a fast electronic pathway,large specific surface area,enhanced electrical conductivity,and improved electrochemical performance.As expected,the obtained CS-2@MXene@Bi_(2)O_(3) binder-free electrode exhibits a high discharge capacitance of 646.1 F g^(–1)(1 A g^(–1)).Two binder-free electrodes can be assembled into a solid-state supercapacitor with desirable energy and power density,and long-term cyclic stability is demonstrated through 5000 cycles.Given these advantages,the CS-2@MXene@Bi_(2)O_(3) is selected as the electrode in a foldable supercapacitor.More importantly,the specific capacitance is reserved after various deformations.Therefore,it is expected that binder-free electrode materials with the unique core@shell structure design could be applied in wearable and portable energy conversion devices.

高溶解性树枝状富勒烯衍生物电子传输材料的合成及其在钙钛矿太阳能电池中的应用

本文设计并合成了一系列单加成的树枝状C_(60)衍生物作为电子传输材料,其中,材料的合成过程采用无催化剂参与的Diels-Alder[4+2]环加成反应。得到的超支化C_(60)的溶解性得到明显提高,与原始的C_(60)相比,第一代和第二代树枝状C_(60)衍生物(C_(60)-G1和C_(60)-G2)在有机相中的溶解度均提高了5倍以上。此外,理论模拟和实验均表明,树枝状C_(60)衍生物可作为钙钛矿太阳能电池的电子传输层,并同时具有良好的溶液加工性能。在钙钛矿太阳能电池中,以C_(60)-G2作为电子传输层的最大光电转换效率可达14.7%。

Enhancing thermal conductivity of silicone rubber composites by insitu constructing SiC networks:A finite-element study based on first principles calculation

Polymer composites as thermal interface materials have been widely used in modern electronic equipment.In this work,we report a novel method to prepare highly through-plane thermally conductive silicone rubber(SR)composites with vertically aligned silicon carbide fibers(VA-SiCFs)entangled by SiC nanowires(SiCNWs)networks.First,a series of carbon fibers(CFs)skeletons were fabricated in sequence of coating poor thermally conductive polyacrylonitrile-based CFs with polydopamine,icetemplated assembly,and freeze-drying processes.Furthermore,VA-SiCFs networks,i.e.,long-range continuous SiCFs-SiCNWs networks,based on the prepared CFs skeletons,were in-situ obtained via template-assisted chemical vapor deposition method.The thermal conductivity enhancement mechanism of VA-SiCFs networks on its SR composites was also intensively studied by finite element simulation,based on the first principles investigation of SiC,and Foygel’s theory.The in-situ grown VA-SiCFs networks possess high intrinsic thermal conductivity without the thermal interface between fillers,acting as the high-efficiency through-plane long-range continuous thermal conduction path,in which the SiCNWs were the in-plane“thermal spreader”.The VA-SiCFs/SR composites reached a high through-plane thermal conductivity,2.13 W/(m·K),at the filler loading of 15 vol.%,which is 868.2%,and 249.2%higher than that of pure SR sample,and random-CFs@polydopamine(PDA)/SR composites at the same content,respectively.The VA-SiCFs/SR composites also exhibited good electrical insulation performance and excellent dimensional stability,which guaranteed the stable interfacial heat transfer of high-power density electronic devices.

Direct ink writing of metal-based electrocatalysts for Li–S batteries with efficient polysulfide conversion

Thanks to the significantly higher energy density compared with universal commercialized Li-ion batteries,lithium–sulfur(Li–S)batteries are being investigated for use in prospective energy storage devices.However,the inadequate electrochemical kinetics of reactants and intermediates hinder commercial utilization.This limitation results in substantial capacity degradation and short battery lifespans,thereby impeding the battery's power export.Meanwhile,the capacity attenuation induced by the undesirable shuttle effect further hinders their industrialization.Considerable effort has been invested in developing electrocatalysts to fix lithium polysulfides and boost their conversion effectively.In the conventional process,the planar electrodes are prepared by slurry-casting,which limits the electron and ion transfer paths,especially when the thickness of the electrodes is relatively large.Compared with traditional manufacturing methods,direct ink writing(DIW)technology offers unique advantages in both geometry shaping and rapid prototyping,and even complex three-dimensional structures with high sulfur loading.Hence,this review presents a detailed description of the current developments in terms of Li–S batteries in DIW of metal-based electrocatalysts.A thorough exploration of the behavior chemistry of electrocatalysis is provided,and the adhibition of metal-based catalysts used for Li–S batteries is summarized from the aspect of material usage and performance enhancement.Then,the working principle of DIW technology and the requirements of used inks are presented,with a detailed focus on the latest advancements in DIW of metal-based catalysts in Li–S battery systems.Their challenges and prospects are discussed to guide their future development.

The Soft-Strain Effect Enabled High-Performance Flexible Pressure Sensor and Its Application in Monitoring Pulse Waves

Flexible and wearable pressure sensors attached to human skin are effective and convenient in accurate and real-time tracking of various physiological signals for disease diagnosis and health assessment.Conventional flexible pressure sensors are constructed using compressible dielectric or conductive layers,which are electrically sensitive to external mechanical stimulation.However,saturated deformation under large compression significantly restrains the detection range and sensitivity of such sensors.Here,we report a novel type of flexible pressure sensor to overcome the compression saturation of the sensing layer by softstrain ffect,enabling an utra-high sensitivity of~636 kPa^(-1) and a wide detection range from 0.1 kPa to 56 kPa.In addition,the cyclic loading-unloading test reveals the excellent stability of the sensor,which maintains its signal detection after 10.000 cycles of 10 kPa compression.The sensor is capable of monitoring arterial pulse waves from both deep tissue and distal parts,such as digital arteries and dorsal pedal arteries,which can be used for blood pressure estimation by pulse transit time at the same artery branch.

仿生细胞膜涂层包覆肿瘤阻断代谢物传输

The metabolite transport inhibition of tumor cells holds promise to achieve anti-tumor efficacy.Herein,we presented an innovative strategy to hinder the delivery of metabolites through the in-situ besieging tumor cells with polyphenolic polymers that strongly adhere to the cytomembrane of tumor cells.Simultaneously,these polymers underwent self-crosslinking under the induction of tumor oxidative stress microenvironment to form an adhesive coating on the surface of the tumor cells.This polyphenol coating effectively obstructed glucose uptake,reducing metabolic products such as lactic acid,glutathione,and adenosine triphosphate,while also causing reactive oxygen species to accumulate in the tumor cells.The investigation of various tumor models,including 2D cells,3D multicellular tumor spheroids,and xenograft tumors,demonstrated that the polyphenolic polymers effectively inhibited the growth of tumor cells by blocking key metabolite transport processes.Moreover,this highly adhesive coating could bind tumor cells to suppress their metastasis and invasion.This work identified polyphenolic polymers as a promising anticancer candidate with a mechanism by impeding the mass transport of tumor cells.

Lightweight foam-like nitrogen-doped carbon nanotube complex achieving highly efficient electromagnetic wave absorption

With the increased electromagnetic wave(EMW)threat to military and human health,the develop-ment of EMW-absorbing materials is crucial.Metal-organic framework derivatives containing magnetic nanoparticles and a carbon matrix are potential candidates for designing efficient EMW-absorbing mate-rials.Herein,a zeolitic imidazolate framework-67(ZIF-67)-embedded three-dimensional melamine foam is pyrolyzed to afford carbon foam-based nitrogen-doped carbon nanotube composites,named 3D foam-like CoO/Co/N-CNTs.Magnetic CoO/Co particles are confined in the dielectric carbon nanotube skeleton.The carbon nanotubes provide considerable conductive loss,while CoO/Co magnetic particles are con-ducive to providing magnetic loss and adjusting impedance matching.Moreover,the numerous defect structures introduced by heteroatomic doping(nitrogen)cause dipole polarization and simultaneously adjust impedance matching.Meanwhile,the unique porous nanotube structure promotes multiple re-flections and scattering of EMWs,further optimizing impedance matching.CoO/Co/N-CNTs composites exhibit a minimum reflection loss of−52.3 dB at a matching thickness of 2.0 mm,while the correspond-ing effective absorption bandwidth is 5.28 GHz at a matching thickness of 2.2 mm.This study reports a novel approach to fabricating a lightweight high-performance EMW-absorbing material.

Materials and structural design for preferable Zn deposition behavior toward stable Zn anodes

Benefiting from the high capacity of Zn metal anodes and intrinsic safety of aqueous electrolytes,rechargeable Zn ion batteries(ZIBs)show promising application in the post‐lithium‐ion period,exhibiting good safety,low cost,and high energy density.However,its commercialization still faces problems with low Coulombic efficiency and unsatisfied cycling performance due to the poor Zn/Zn2+reversibility that occurred on the Zn anode.To improve the stability of the Zn anode,optimizing the Zn deposition behavior is an efficient way,which can enhance the subsequent striping efficiency and limit the dendrite growth.The Zn deposition is a controlled kinetics‐diffusion joint process that is affected by various factors,such as the interaction between Zn2+ions and Zn anodes,ion concentration gradient,and current distribution.In this review,from an electrochemical perspective,we first overview the factors affecting the Zn deposition behavior and summarize the modification principles.Subsequently,strategies proposed for interfacial modification and 3D structural design as well as the corresponding mechanisms are summarized.Finally,the existing challenges,perspectives on further development direction,and outlook for practical applications of ZIBs are proposed.

An odyssey of lithium metal anode in liquid lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries exhibit outstanding energy density and material sustainability.Enormous effects have been devoted to the sulfur cathode to address redox kinetics and polysulfide intermediates shuttle.Recent attentions are gradually turning to the protection of the lithium metal anodes,since electrochemical performances of Li-S batteries are closely linked to the working efficiency of the anode side,especially in pouch cells that adopt stringent test protocols.This Perspective article summarizes critical issues encountered in the lithium metal anode,and outlines possible solutions to achieve efficient working lithium anode in Li-S batteries.The lithium metal anode in Li-S batteries shares the common failure mechanisms of volume fluctuation,nonuniform lithium flux,electrolyte corrosion and lithium pulverization occurring in lithium metal batteries with oxide cathodes,and also experiences unique polysulfide corrosion and massive lithium accumulation.These issues can be partially addressed by developing three-dimensional scaffold,exerting quasi-solid reaction,tailoring native solid electrolyte interphase(SEI)and designing artificial SEI.The practical evaluation of Li-S batteries highlights the importance of pouch cell platform,which is distinguished from coin-type cells in terms of lean electrolyte-to-sulfur ratio,thin lithium foil,as well as sizable total capacity and current that are loaded on pouch cells.This Perspective underlines the development of practically efficient working lithium metal anode in Li-S batteries.

Investigation of a complete squeeze-film damping model for MEMS devices

Dynamic performance has long been critical for micro-electro-mechanical system(MEMS)devices and is significantly affected by damping.Different structural vibration conditions lead to different damping effects,including border and amplitude effects,which represent the effect of gas flowing around a complicated boundary of a moving plate and the effect of a large vibration amplitude,respectively.Conventional models still lack a complete understanding of damping and cannot offer a reasonably good estimate of the damping coefficient for a case with both effects.Expensive efforts have been undertaken to consider these two effects,yet a complete model has remained elusive.This paper investigates the dynamic performance of vibrated structures via theoretical and numerical methods simultaneously,establishing a complete model in consideration of both effects in which the analytical expression is given,and demonstrates a deviation of at least threefold lower than current studies by simulation and experimental results.This complete model is proven to successfully characterize the squeeze-film damping and dynamic performance of oscillators under comprehensive conditions.Moreover,a series of simulation models with different dimensions and vibration statuses are introduced to obtain a quick-calculating factor of the damping coefficient,thus offering a previously unattainable damping design guide for MEMS devices.

Quasi-One-Dimensional van der Waals Transition Metal Trichalcogenides

The transition metal trichalcogenides(TMTCs)are quasi-one-dimensional(1D)MX_(3)-type van der Waals layered semiconductors,where M is a transition metal element of groups IV and V,and X indicates chalcogen element.Due to the unique quasi-1D crystalline structures,they possess several novel electrical properties such as variable bandgaps,charge density waves,and superconductivity,and highly anisotropic optical,thermoelectric,and magnetic properties.The study of TMTCs plays an essential role in the 1D quantum materials field,enabling new opportunities in the material research dimension.Currently,tremendous progress in both materials and solid-state devices has been made,demonstrating promising applications in the realization of nanoelectronic devices.This review provides a comprehensive overview to survey the state of the art in materials,devices,and applications based on TMTCs.Firstly,the symbolic structure,current primary synthesis methods,and physical properties of TMTCs have been discussed.Secondly,examples of TMTC applications in various fields are presented,such as photodetectors,energy storage devices,catalysts,and sensors.Finally,we give an overview of the opportunities and future perspectives for the research of TMTCs,as well as the challenges in both basic research and practical applications.

Hydrogel-based flexible materials for diabetes diagnosis,treatment,and management

Diabetes is a chronic metabolic disease characterized by high glucose concentration in blood.Conventional management of diabetes requires skin pricking and subcutaneous injection,causing physical pain and physiological issues to diabetic individuals.Hydrogels possess unique advantages such as lightweight,stretchability,biocompatibility,and biodegradability,offering the opportunities to be integrated as flexible devices for diabetes management.This review highlights the development of hydrogels as flexible materials for diabetes applications in glucose monitoring,insulin delivery,wound care,and cell transplantation in recent years.Challenges and prospects in the development of hydrogel-based flexible devices for personalized management of diabetes are discussed as well.

DMD-based hyperspectra I microscopy with flexible multiline parallel scanning

As one of the most common hyperspearal microscopy(HSM)techniques,line-scanning HSM is currently utilized in many fields.However,its scanning efficiency is still considered to be inadequate since many biological and chemical processes occur too rapidly to be captured.Accordingly,in this work,a digital micromirror device(DMD)based on microelectromechanical systems(MEMS)is utilized to demonstrate a flexible multiline scanning HSM system.To the best of our knowledge,this is the first line-scanning HSM system in which the number of scanning lines N can be tuned by simply changing the DMD's parallel scanning units according to diverse applications.This brilliant strategy of effortless adjustability relies only on on-chip scanning methods and totally exploits the benefits of parallelization,aiming to achieve nearly an A/-time improvement in the detection efficiency and an N-time decrease in the scanning time and data volume compared with the single-line method under the same operating conditions.To validate this,we selected a few samples of different spectral wavebands to perform reflection imaging,transmission imaging,and fluorescence imaging with varying numbers of scanning lines.The results show the great potential of our DMD-based HSM system for the rapid development of cellular biology,material analysis,and so on.In addition,its on-chip scanning process eliminates the inherent microscopic architecture,making the whole system compact,lightweight,portable,and not subject to site constraints.

Recommendation System with Biclustering

The massive growth of online commercial data has raised the request for an automatic recommender system to benefit both users and merchants.One of the most frequently used recommendation methods is collaborative filtering,but its accuracy is limited by the sparsity of the rating dataset.Most existing collaborative filtering methods consider all features when calculating user/item similarity and ignore much local information.In collaborative filtering,selecting neighbors and determining users’similarities are the most important parts.For the selection of better neighbors,this study proposes a novel biclustering method based on modified fuzzy adaptive resonance theory.To reflect the similarity between users,a new measure that considers the effect of the number of users’common items is proposed.Specifically,the proposed novel biclustering method is first adopted to obtain local similarity and local prediction.Second,item-based collaborative filtering is used to generate global predictions.Finally,the two resultant predictions are fused to obtain a final one.Experiment results demonstrate that the proposed method outperforms state-of-the-art models in terms of several aspects on three benchmark datasets.

氮磷共掺杂碳负载WC/WP异质结的电催化析氢性能研究

廉价、高效、稳定的非铂析氢催化剂是电解水制氢技术发展的关键.WC具有类似铂的电子结构,且价格低廉,是极具潜力的析氢催化剂.然而,反应中间体W-H的结合力强,不利于H解离,导致析氢性能不佳.针对这一难题,本工作利用与WC晶体结构兼容性好,且具有富电子特性的WP来调控其电子结构,通过一步原位固相界面反应成功制备了氮磷共掺杂碳负载WC/WP异质结(WC/WP@NPC)催化剂.密度泛函理论计算表明,该异质结设计有效减小了W-H键键强,使材料具有更适中的氢原子吸附自由能(−0.05 eV).得益于WC/WP异质结与氮磷共掺杂碳之间的协同增效作用,WC/WP@NPC在酸性和碱性电解质中均表现出了优异的催化性能.本工作为高效非铂析氢催化剂的设计制备提供了新思路.

Recycling strategies for vitrimers

Vitrimer is a new type of material that combine the advantages of thermoplastic and thermoset materials.The rapid dynamic exchange reactions at high temperature allow the topology of cross-linked networks to change and rearrange while keeping material structures and properties intact.The concept of vitrimer has emerged to provide a viable strategy for the recycling of highperformance polymer materials,and lots of research works have been carried out for the development of various types of vitrimers.In addition,the recycling strategies for vitrimers are particularly important to determine the performance and potential applications of the recovered materials.Therefore,it is an innovative and valu-able perspective to discuss vitrimer materials according to their different recycling strategies.In this review,we start with a brief overview of vitrimers,and then,focus on recycling strategies for vitrimers.Specifically,we highlight the advantages and disadvan-tages of the two different recycling strategies:physical and chemi-cal recycling methods,and then explore the feasibility of upcycling vitrimers using 3D printing technology.Finally,the impact of recy-cling strategies on vitrimer materials and the prospects for max-imizing the use of vitrimer materials are discussed.

Hole-Transporting Low-Dimensional Perovskite for EnhancingPhotovoltaic Performance

Halide perovskites with low-dimensionalities(2D or quasi-2D)have demonstrated outstanding stabilities compared to their 3D counterparts.Nevertheless,poor charge-transporting abilities of organic components in 2D perovskites lead to relatively low power conversion efficiency(PCE)and thus limit their applications in photovoltaics.Here,we report a novel hole-transporting low-dimensional(HT2D)perovskite,which can form a hole-transporting channel on the top surface of 3D perovskite due to self-assembly effects of metal halide frameworks.This HT2D perovskite can significantly reduce interface trap densities and enhance hole-extracting abilities of a heterojunction region between the 3D perovskite and hole-transporting layer.Furthermore,the posttreatment by HT2D can also reduce the crystal defects of perovskite and improve film morphology.As a result,perovskite solar cells(PSCs)can effectively suppress nonradiative recombination,leading to an increasement on photovoltage to>1.20 V and thus achieving>20%power conversion efficiency and>500 h continuous illumination stability.This work provides a pathway to overcome charge-transporting limitations in low-dimensional perovskites and delivers significant enhancements on performance of PSCs.

Review on piezoelectric actuators:materials,classifications,applications,and recent trends

Piezoelectric actuators are a class of actuators that precisely transfer input electric energy into displacement,force,or movement outputs efficiently via inverse piezoelectric effect-based electromechanical coupling.Various types of piezoelectric actuators have sprung up and gained widespread use in various applications in terms of compelling attributes,such as high precision,flexibility of stoke,immunity to electromagnetic interference,and structural scalability.This paper systematically reviews the piezoelectric materials,operating principles,representative schemes,characteristics,and potential applications of each mainstream type of piezoelectric actuator.Herein,we intend to provide a more scientific and nuanced perspective to classify piezoelectric actuators into direct and indirect categories with several subcategories.In addition,this review outlines the pros and cons and the future development trends for all kinds of piezoelectric actuators by exploring the relations and mechanisms behind them.The rich content and detailed comparison can help build an in-depth and holistic understanding of piezoelectric actuators and pave the way for future research and the selection of practical applications.