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PSU has strong interaction with lithium ions, which is responsible for the uniform distribution of Li+. PE are functionalized with both PSU and PVDF (PESV), Li/Li cell with PESV cycles stably without noticeable current change for nearly 1000 h.

The membrane-disruptive activity of PEG-PAEMA nanoparticles are silenced at physiological pH, while activated by characteristic tumor acidity via protonation of the PAEMA block, resulting in high selectivity towards tumors.

We propose an active Au–Zn nanomotor driven by water and discovered an interesting adaptive interaction mode of diffusiophoretic Au–Zn nanomotors with passive condensate particles in different environments.

With iso-butyl formate (IF) as anti-freezing agent, a fluorine–sulfur electrolyte is designed to achieve low coordination number, high desolvation energy and stable LiF-rich interphase, and enables the stable operation of an electric fan at −70 °C.

PurposeThe purpose of this paper is to propose an improved method which can shorten the calculation time and improve the calculation efficiency under the premise of ensuring the calculation accuracy for calculating the response of dynamic systems with periodic time-varying characteristics.Design/methodology/approachAn improved method is proposed based on Runge–Kutta method according to the composition characteristics of the state space matrix and the external load vector formed by the reduction of the dynamic equation of the periodic time-varying system. The recursive scheme of the holistic matrix of the system using the Runge–Kutta method is improved to be the sub-block matrix that is divided into the upper and lower parts to reduce the calculation steps and the occupied computer memory.FindingsThe calculation time consumption is reduced to a certain extent about 10–35% by changing the synthesis method of the time-varying matrix of the dynamics system, and the method proposed of paper consumes 43–75% less calculation time in total than the original Runge–Kutta method without affecting the calculation accuracy. When the ode45 command that implements the Runge–Kutta method in the MATLAB software used to solve the system dynamics equation include the time variable which cannot provide its specific analytic function form, so the time variable value corresponding to the solution time needs to be determined by the interpolation method, which causes the calculation efficiency of the ode45 command to be substantially reduced.Originality/valueThe proposed method can be applied to solve dynamic systems with periodic time-varying characteristics, and can consume less calculation time than the original Runge–Kutta method without affecting the calculation accuracy, especially the superiority of the improved method of this paper can be better demonstrated when the degree of freedom of the periodic time-varying dynamics system is greater.

Recent years have witnessed a successful rise of the time synchronized gossiping comment, or so-called danmu combined with online videos. This new business mode has enriched communication among users by sending users' feelings through danmus and sharing these danmus on time synchronized videos. Can danmu communication be helpful for better user behavior modeling or video analyzing? To this question, in this paper, preliminary attempts are made on analysis of users and videos by introducing a Danmu dataset which is collected from a real-world danmu-enabled video sharing platform. The dataset contains 1.7 TB of videos and danmus in total across 8 video categories. With a focus on the 7.9 million danmus records and 4.8 million video frames, we first perform the basic statistic analysis and high-level semantic analysis. After that, we show some of the previous work on this area, including user behavior modeling, fine-grained video understanding and labeling, video plot generation and image-enhanced semantic understanding. For each application, we also propose its possible future directions. We hope this new dataset will inspire new ideas in areas among language, multimedia and user understanding.

High-voltage cathodes paired with lithium metal anode have aroused extensive interests owing to their application potentials for high-density energy storage. Nevertheless, conventional electrolytes fail to maintain the stability of high-voltage cathodes and Li anode, due to their rigid interfacial chemistry with low adsorption of transition metal and strong bonding with Li+ ions. These inadequate interactions exacerbate issues such as transition metal dissolution and non-uniform Li+ transference, ultimately resulting in low cyclability of high-voltage lithium metal batteries (HVLMBs). By incorporating fluoroethylene carbonate (FEC) into lithium bis(trifluoromethane sulfonyl) imide (LiTFSI)/tetramethylene sulfone (TMS) solution, we design a sulfone-based electrolyte to improve the cyclability of HVLMBs with bi-electrode affinity characteristic—the TMS solvent with outstanding anti-oxidation stability preferentially tends to the aggressive cathodes while the FEC solvent with excellent film-forming ability approaches to the Li anode, attributed to the different adsorption energy between various solvents and electrodes. In addition, the sulfone electrolyte forms ultra-thin fluorine and sulfur-rich interphases, containing LiSO2F with S=O bonds of low electron density, associated with Li+ and e− species attacking the S-C and S-N bonds of LiTFSI and the S-C bonds of TMS. As confirmed by in-situ Raman, Ab initio molecular dynamics, and phase field simulations, the LiSO2F uniformizes in-plane Li+ transfer and mitigates transition metal dissolution, owing to the smallest Li+-LiSO2F bonding value (-1.95 eV) and the largest transition metal absorption value with LiSO2F (-3.86 eV) ever reported in the interfacial components. With Coulombic efficiency of 99.3%, the electrolyte enables an 86.1% retention after 500 cycles for Li/NMC811 (4.40 V) batteries.

MAPbBr3 single crystals (SCs) were obtained by a low-temperature controllable metastable crystallization method, which regulates the growth process to low temperature and ensures excellent optoelectronic properties of the as-prepared SCs.

The shuttle effect of lithium polysulfides (LiPSs) and sluggish redox conversion significantly hinder practical implementation of lithium-sulfur batteries (LSBs). To overcome these issues, herein, we present MoP quantum dots anchored N, P-doped graphene (MPQ@G) as a multifunctional LSB cathode. The N, P-doped graphene layers serve as a conductive skeleton to support the MoP QDs which can accelerate the electron transfer, physically hinder the polysulfide migration and thus enhance the electrochemical performance. More importantly, as a polar and conductive catalyst, MoP QDs provide catalytically active sites for the conversion of LiPSs. As a result, the LSBs with MPQ@G/S cathodes deliver an elevated initial capacity of 1220.2 mAh g−1 at 0.2 C and remain 98.9% after rate cycles, signifying its exceptional cycling stability. Moreover, it displays a large capacity of 681.2 mAh g−1 even at a high rate of 1 C. The Li-S pouch cell also presents high specific capacities and preeminent cycling stabilities, confirming its great potential for high-rate applications. Density functional theory calculations demonstrate the improved absorptivity and redox conversion reversibility of LiPSs. This work provides an efficient strategy to improve composite with highly adsorptive and catalytic properties for high-performance Li-S batteries.

Interferon-γ (IFN-γ) plays contradictory roles in tumor immunology: (I) to activate positive host's immunity for eliminating tumor; (II) to induce negative adaptive immune resistance via up-regulating programmed death ligand-1 (PD-L1) expression for tumors to evade immune surveillance. The negative feedback loop between the IFN-γ recovery and the IFN-γ-induced PD-L1 up-regulation puts postoperative adjuvant chemotherapy into a dilemma. It is of great significance but challenging to manipulate the double-edge effects of IFN-γ against postoperative tumor progression. Herein, a platelet-engineered nanoplatform (PMF@DR NPs) capable of harmonizing janus-faced nature of IFN-γ was designed via uniquely co-assembling doxorubicin (Dox) and cyclin-dependent kinase 5 inhibitor roscovitine (Rosco) with platelet membrane fragment (PMF) as the particulate stabilizer. With PMF@DR NPs navigated by PMF to residual tumor, the Dox-activated immune response recovered IFN-γ secretion for positive host's immunity, while the IFN-γ-induced negative adaptive immune resistance was potently overcome by Rosco via disabling PD-L1 expression without dependence of IFN-γ stimulation. The negative feedback loop between IFN-γ recovery and PD-L1 up-regulation was thus potently disrupted in postoperative adjuvant chemotherapy. Our PMF@DR NPs not only harmonized janus-faced nature of IFN-γ to effectively regulate postoperative tumor progression, but also illustrated an innovative strategy for high-drug-loading biomimic nanoplatform.

Lithium-based batteries are promising and encouraging energy storage devices in different fields such as portable electronic equipment and new-energy vehicles. Separator, which serves as a physical blockade between electrodes as well as a reliable bridge for ion transport, plays a vital role in maintaining the sustainability of batteries. Unfortunately, most studies in the field of lithium-based batteries have only focused on separators between 20-25 μm so as to achieve a balance between battery safety and performance. However, such thick separators come at the expense of less free space for accommodating active materials inside the battery, thus impeding further development of next-generation lithium-based batteries with high energy density. Thin separators with robust mechanical strength are undoubtedly prime choice to make lithium-based batteries more reliable and safer. This review focuses mainly on recent developments in thin separators for lithium-based batteries, lithium-ion batteries (LIBs) and lithium-sulfur (Li-S) batteries in particular, with a detailed introduction of thin separator preparation methodologies and an analysis of new progress in separators owning the thickness less than 15 μm or an ultrathin functional layer less than 1 μm. Effects of separator thickness on energy density are explored through practical evaluation. Furthermore, a brief outlook for realizing an ‘infinitely-thin’ separator with excellent physical performances and negligible resistance is provided.

Waste cooking oils (WCOs) are a cheap and rich source of carbon and hydrogen, and they exhibit great potential for the preparation of hydrogen gas and carbon nanomaterials. Here, we prepared three Pt–Ni/SBA-15 catalysts with Pt contents ranging from 0 to 2% to examine their activity in the catalytic cracking of WCO towards the production of hydrogen and carbon nanotubes (CNTs). A mixture of soybean oil, oleic acid and animal fat was used as a model compound of WCO, and the catalysts were characterised by inductively coupled plasma–optical emission spectrometry, scanning and transmission electron microscopy, X-ray diffraction, N2 adsorption–desorption isotherms, temperature programmed reduction, thermogravimetric analysis and Raman spectroscopy. The effect of Pt loading and cracking temperature on the hydrogen production and the quality of CNTs was also evaluated. Among the prepared catalysts, 2%Pt–30%Ni/SBA-15 showed excellent catalytic activity at 750 °C, affording a maximum hydrogen content of 66.2 vol%, while CNTs with diameters of 20–100 nm and high crystallinity, oxidation stability, graphitisation and purity were also prepared.

Recently, a burgeoning category of biocompatible botanically derived nanomaterial cellulose nanofibers (CNFs) has captured tremendous attention on account of its entangled nanostructured network, natural abundance, and outstanding mechanical properties. Biomimetically inspired by the superior properties of CNFs, this paper examined them as the coating material to cover cyclotrimethylenetrinitramine (RDX), cyclotetramethylenetetranitramine (HMX), and hexanitrohexaazaisowurtzitane (CL-20) via a facile water suspension method and the ultrasonic technology. The core-shell structure and the composition of energetic crystal@CNF were examined through scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy analyses. The obtained outcomes demonstrated that the dispersibility of the CNF enhanced favorably upon covering the surface of explosive crystals; the interfacial contact ability between CNFs and energetic crystals was also manifested to be increased, which could be ascribed to the interfacial interaction of hydrogen bonds and the electrostatic force of self-assembly. In addition, the stable crystalloid construction of β-HMX and ε-CL-20 has been preserved positively in the preparation process. In comparison with raw explosives, the thermal stability and sensitivity performances of the core-shell structure composites were outstanding. Accordingly, this work demonstrated the rewarding application of coating CNFs uniformly on the surface of energetic crystals, ulteriorly offering a potential fabrication strategy for the embellishment of high-explosive crystals.

Nanofiber membranes are widely employed to prepare composite filter media. The traditional composite method of hot pressing may damage the structure of nanofiber membrane, and thus increase the pressure drop through the composite filter. In this study, three-dimensional PET/TPU (polyethylene terephthalate/thermoplastic polyurethane) composite nanofiber filters (PET/TPU-CNF) with beads-on-string structure were fabricated by one-step co-electrospinning. Besides a stronger adhesion strength of 1.385 N/cm between the nanofiber membrane and substrate, the PET/TPU-CNF presented a low pressure drop of 28.96 Pa and a filtration efficiency of 83.64% for ambient particles at a face velocity of 5.3 cm/s. A high tensile strength of 4.33 MPa was measured for the PET/TPU nanofiber membrane. Thanks to the beads-on-string structure, both the mechanical properties and filtration performances of PET/TPU-CNF were enhanced compared with the pure PET nanofiber composite filter. The present study provides a new route to improve the membrane adhesion strength of nanofiber membrane coated filters., Powder Technology, 387, ISSN:0032-5910, ISSN:1873-328X

Expanding interspace and introducing vacancies are desired to promote the mobility of Zn ions and unlock the inactive sites of layered cathodes. However, this two-point modulation has not yet been achieved simultaneously in vanadium phosphate. Here, a strategy is proposed for fabricating an alcohol-based organic-inorganic hybrid material, VO

SARS-CoV-2 spreads

SARS-CoV-2 spreads via droplets, aerosols, and smear infection. From the beginning of the COVID-19 pandemic, using a facemask in different locations was recommended to slow down the spread of the virus. To evaluate facemasks’ performance, masks’ filtration efficiency is tested for a range of particle sizes. Although such tests quantify the blockage of the mask for a range of particle sizes, the test does not quantify the cumulative amount of virus-laden particles inhaled or exhaled by its wearer. In this study, we quantify the accumulated viruses that the healthy person inhales as a function of time, activity level, type of mask, and room condition using a physics-based model. We considered different types of masks, such as surgical masks and filtering facepieces (FFPs), and different characteristics of public places such as office rooms, buses, trains, and airplanes. To do such quantification, we implemented a physics-based model of the mask. Our results confirm the importance of both people wearing a mask compared to when only one wears the mask. The protection time before the healthy wearer has an infection risk of 50% reduces by 80% if only one wears the facemask instead of both people. The protection time is further reduced if the infected person starts to cough or increases the activity level by 85% and 99%, respectively. Results show the leakage of the mask can considerably affect the performance of the mask. For the surgical mask, the apparent filtration efficiency reduces by 75% with such a leakage, which cannot provide sufficient protection despite the high filtration efficiency of the mask. The facemask model presented provides key input in order to evaluate the protection of masks for different conditions in public places. The physics-based model of the facemask is provided as an online application.

As promising electrode materials, transition metal oxides have attracted considerable attention owing to their excellent performance in electrochemical energy storage. However, their poor conductivity and fragile structure limit their practical application. In this study, a binder-free nickel oxide/oxynitride network (NiON WS) bifunctional electrodes with cation multivalent states that exhibit high energy storage performance were synthesized for the first time. The massive active sites, high specific surface areas, and multiple cation valence states of NiON WS were advantageous for electrochemical redox reaction during its application in supercapacitors (1283.5 mF cm−2) and lithium-ion batteries (1345.0 mA h g−1). Particularly, the NiON WS based flexible asymmetric SCs exhibit excellent capacitance and energy densities. First-principle calculations were employed to study the mechanism of the electrochemical performance improvement of NiON WS. This study demonstrates the potential of transition metal oxides electrode with high capacity and activity for electrochemical energy storage and conversion.

Lithium-ion batteries (LIBs) are considered as one of the most successful energy storage technologies due to the high energy density, long cyclability and no memory effect. With the ever-increasing energy density of LIBs in practical applications, operational safety becomes more critical because unintentional release of energy can lead to devastating accidents related to fire and explosions of LIBs. The flammable polymer separators and liquid electrolytes are the root causes of such safety hazards. For the advancement of safe LIB design, this review summarizes the recent developments towards highly flame-retardant separators and solid-state electrolytes. The composition, structure and the performance of flame-retardant separators for liquid LIBs are firstly discussed, which include inorganic particle blended polymer separators, ceramic material coated separators, inherently nonflammable polymer separators, and separators with flame-retardant additives. Then much attention is paid on the solid-state electrolytes including inorganic solid electrolytes, solid polymer electrolytes, and inorganic/organic composite electrolytes. Future outlooks for the challenges of flame-retardant separators to practical applications are also discussed.

In this study, a novel nitrated bacterial cellulose/2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/ammonium perchlorate nanoenergetic composite was successfully prepared by the sol–gel ...

Sodium-selenium (Na-Se) batteries have aroused enormous attention due to the large abundance of the element sodium as well as the high electronic conductivity and volumetric capacity of selenium. In this battery system, some primary advances in electrode materials have been achieved, mainly involving the design of Se-based cathode materials. In this Review, the electrochemical mechanism is discussed, thus revealing the main challenges in Na-Se batteries. Then, the advances in the design of Se-based cathode materials for Na-ion storage are systemically summarized, classified, and discussed, including Se/carbon composite, Se/polar material/carbon composites, and hybrid SexSy alloys. Some potential strategies enabling the improvement of crucial challenges and enhancement of electrochemical performance are also proposed to provide guidelines for the enhancements of Na-ion storage. An outlook for future valuable research directions is proposed to understand more deeply the electrochemical mechanism of Na-Se batteries and promote their further developments in full cell performance and commercialization.

Gear transmission is one of the most important and widely used equipment in mechanical transmission. To a certain extent, The technical level, design ability and manufacturing level of gears are important symbols to measure the industrialization level of a country. Cycloid gear drive is a kind of wide applications of gear transmission which is studied and developed actively in the world. A new type of cycloid drive is called Output-Pin-Wheel, and it has been obtained through structural innovation. It has lots of advantages, such as small in size, light in weight, large transmission ratio range, high transmission efficiency, stable transmission, low noise, reliable operation, long service life and so on, which make it possible to be widely used in various industrial fields. Although at present, it has a set of more mature design method, This paper does development for Creo based on Microsoft Visual Studio 2005 platform and uses FEA to solve those problems, for the purposes of improving design efficiency and shortening design cycle. The development system has a friendly man-machine interaction interface, so the fast interactive parametric modeling and analysis of main components of reducer can be implemented by using this method, such as cycloid gear, pin-wheel, eccentric shaft, bearings, input shaft etc. On the base of parametric model of reducer, the finite elements contact analysis between the cycloid gear and pins wheel was done by ANSYS software for further research. The results of displacement, stress, strain and contact pressure distribution were obtained. and a set of optimized parameters were obtained also. By optimizing parameters such as eccentricity and pin sleeve radius, the contact stress of gears is reduced by 31.2%, and the transmission load-carrying capacity is improved.

Inert particles are widely used as surrogates for biological particles in filtration tests. However, there is always a concern that the different physical properties between inert particles and biological particles may affect the filtration efficiencies of filter media. In the present study, the inert particles, e.g. NaCl and polystyrene latex (PSL), and biological particles, e.g. E.coli, B.sublitis, bovine serum albumin (BSA), and endotoxin, were used to evaluate the filtration efficiencies of the filtering materials of a surgical mask and a N95-rated respirator. The results showed that the difference in the filtration efficiencies of the N95-rated respirator for the tested inert particles and biological particles was smaller than 0.02%. The filtration efficiency of the surgical mask for PSL particles was lower than that for E.coli and B.subtilis particles with the same aerodynamic diameter because of the larger interception lengths of E.coli and B.subtilis particles. The average filtration efficiencies of the surgical mask for the tested NaCl particles and biological particles in the size range of 20–600 nm were similar. For the monodisperse particles, the filtration efficiency of the surgical mask for NaCl, BSA and endotoxin particles in the size range of 50–250 nm decreased in the above order due to the different shapes, dielectric properties, and multiply-charged fractions of the particles. The surgical mask presented the highest filtration efficiency for BSA particles and the lowest filtration efficiency for NaCl particles when the particle size was larger than 300 nm, which could be related to the difference in the electrostatic deposition and bounce probabilities. The present work revealed that the influence of several particle characteristics such as shape, dielectric property, and charge state on filtration efficiency should be considered when using common inert particles to replace biological particles to measure efficiencies of air filters., Separation and Purification Technology, 313, ISSN:1383-5866

In this study, nitrated bacterial cellulose (NBC) energetic binder was introduced to prepare NBC-based nanocomposite energetic materials (nEMs) through a combined simple and safe sol–gel method and...