Preparation of Environmentally Friendly Urea-Hexanediamine-Glyoxal(HUG)Resin Wood Adhesive

Using non-toxic,low-volatile glyoxal to completely replace formaldehyde for preparing urea-glyoxal(UG)resin adhesive is a hot research topic that could be of great interest for the wood industry.However,urea-glyoxal(UG)resins prepared by just using glyoxal instead of formaldehyde usually yields a lower degree of polymerization.This results in a poorer bonding performance and water resistance of UG resins.A good solution is to pre-react urea to preform polyurea molecules presenting already a certain degree of polymerization,and then to condense these with glyoxal to obtain a novel UG resin.Therefore,in this present work,the urea was reacted with hexamethylene diamine to form a polyurea named HU,and then this was used to react it with different amounts of glyoxal to synthesize hexamethylenediamine-urea-glyoxal(HUG)polycondensation resins,and to use this for bonding plywood.The results show that the glyoxal can well react with HU polyuria via addition and schiff base reaction,and also the HUG resin exhibits excellent bonding strength and water resistance.The shear strength of the plywood bonded with this HUG at 160°C hot press temperature as high as 1.93 MPa,2.16 MPa and 1.61 MPa,respectively,which meets the requirement of the China national standard GB/T 9846-2015(≥0.7 MPa),and can be a good choice as a wood adhesive for industrial application.

MALDI ToF Investigation of the Reaction of Soy Protein Isolate with Glutaraldehyde for Wood Adhesives

Soy protein adhesives are currently a hot research topic in the wood panels industry for the abundant raw material reserves,reasonable price and outstanding environmental features.But their poor water resistance,low bonding strength and intolerance to mold are major drawbacks,so that proper modification before use is essential.Glutaraldehyde is one of the more apt cross-linking agents for soybean protein adhesives,which can effectively improve the bonding strength and water resistance of the adhesive.Equally,glutaraldehyde is also an efficient and broad-spectrum fungicide that can significantly improve the anti-fungal properties of a soy protein adhesive.In the work presented here,matrix assisted laser desorption ionization(MALDI-ToF)mass spectrometry and Fourier transform infrared spectroscopy techniques were used to analyze the reaction mechanism of glutaraldehyde cross-linking soybean protein.The results confirmed the reaction of the aldehyde group with amino groups of the side chains and the amide groups of the peptide linkages constituting the skeletal chain of the protein.The laboratory plywood and particleboard bonded with glutaraldehyde-soy bean protein adhesives were prepared to determine the adhesive bonding properties,the dry strength,24 h cold water soaking wet strength and 3 h hot water(63°C)wet strength of plywood were 2.03,1.13 and 0.75 MPa,respectively,which satisfied the requirements of industrial production.

Novel design and synthesis of 1D bamboo-like CNTs@Sn_(4)P_(3)@C coaxial nanotubes for long-term sodium ion storage

In this work,a novel bamboo-like carbon nanotubes@Sn4P3@carbon(BLCNTs@Sn_(4)P_(3)@C)coaxial nanotubes are designed and prepared using a newly developed hydrothermal method followed by a phophidation process.The prepared Sn_(4)P_(3) nanoparticles are uniformly coated and wrapped on the one-dimensional(1D)bamboo-like CNTs,which is covered by a uniform carbon layer to form a sandwich-like structure with Sn_(4)P_(3) in between.The inner CNT and outer carbon can effectively maintain the structural stability and serve as the good electron conductors.Additionally,the outer carbon coating layer can effectively keep BLCNTs@Sn_(4)P_(3)@C nanotubes separate each other,preventing aggregation of Sn_(4)P_(3) during charge/discharge when this material is used as anode for sodium ion batteries.The anode of BLCNTs@Sn_(4)P_(3)@C shows excellent reversible capacity and a long cycling of over 2000 cycles.The unique design of coaxial nanotubes is greatly beneficial to the electrochemical performance of Sn_(4)P_(3) for sodium ion storage.

Aptamers targeting SARS-CoV-2 nucleocapsid protein exhibit potential ant1ip1 an-coronavirus activity

Emerging and recurrent infectious diseases caused by human coronaviruses(HCoVs)continue to pose a significant threat to global public health security.In light of this ongoing threat,the development of a broad-spectrum drug to combat HCoVs is an urgently priority.Herein,we report a series of anti-pan-coronavirus ssDNA aptamers screened using Systematic Evolution of Ligands by Exponential Enrichment(SELEX).These aptamers have nanomolar affinity with the nucleocapsid protein(NP)of Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and also show excellent binding efficiency to the N proteins of both SARS,MERS,HCoV-OC43 and-NL63 with affinity KD values of 1.31 to 135.36 nM.Such aptamer-based therapeutics exhibited potent antiviral activity against both the authentic SARS-CoV-2 prototype strain and the Omicron variant(BA.5)with EC50 values at 2.00 nM and 41.08 nM,respectively.The protein docking analysis also evidenced that these aptamers exhibit strong affinities for N proteins of pan-coronavirus and other HCoVs(−229E and-HKU1).In conclusion,we have identified six aptamers with a high pan-coronavirus antiviral activity,which could potentially serve as an effective strategy for preventing infections by unknown coronaviruses and addressing the ongoing global health threat.

Van der Waals materials-based floating gate memory for neuromorphic computing

With the advent of the“Big Data Era”,improving data storage density and computation speed has become more and more urgent due to the rapid growth in different types of data.Flash memory with a floating gate(FG)structure is attracting great attention owing to its advantages of miniaturization,low power consumption and reli-able data storage,which is very effective in solving the problems of large data capacity and high integration density.Meanwhile,the FG memory with charge storage principle can simulate synaptic plasticity perfectly,breaking the traditional von Neumann computing ar-chitecture and can be used as an artificial synapse for neuromorphic computations inspired by the human brain.Among many candidate materials for manufacturing devices,van der Waals(vdW)materials have attracted widespread attention due to their atomic thickness,high mobility,and sustainable miniaturization properties.Owing to the arbitrary stacking ability,vdW heterostructure combines rich physics and potential 3D integration,opening up various possibilities for new functional integrated devices with low power consumption and flexible applications.This paper provides a comprehensive review of memory devices based on vdW materials with FG structure,including the working principles and typical structures of FG structure devices,with a focus on the introduction of various highperformance FG memories and their versatile applications in neuro-morphic computing.Finally,the challenges of neuromorphic devices based on FG structures are also discussed.This review will shed light on the design and fabrication of vdW material-based memory devices with FG engineering,helping to promote the development of practical and promising neuromorphic computing.

阿秒光源在材料领域的应用

21世纪以来,阿秒(attosecond,1 as=10^(-18)s)技术从诞生逐渐走向快速发展,为我们带来了前所未有的时间分辨(time-resolved)探测能力.以往飞秒(1 fs=10–15s)泵浦-探测(pump-probe)超快光谱技术被广泛应用于材料的超快动力学研究,其脉宽和光子能量可以很好地研究由外层电子决定的材料物性.阿秒技术的出现使我们有可能研究更快的物理过程以及由内层电子决定的物性.本文介绍阿秒瞬态吸收谱(attosecond transient absorption spectroscopy)、阿秒时间分辨角分辨光电子能谱(attosecond time-resolved angular-resolved photoelectron spectroscopy)和中红外超快光谱(mid-infrared ultrafast spectroscopy)等三种超快泵浦-探测技术及其在材料领域的典型应用实例,并对阿秒光源在材料领域的应用前景进行展望.

Highly stable aqueous zinc-ion batteries enabled by suppressing the dendrite and by-product formation in multifunctional Al^(3+) electrolyte additive

Rechargeable aqueous zinc-ion batteries(ZIBs)have gained extensive attention owing to the high safety,low cost,and high power/energy densities.But unfortunately the ZIBs universally suffer from the highly damaging series of side reactions,majorly including the insulating products formation,dendritic growth of zinc,and hydrogen evolution.To date there are few reports on the effective strategy that can solve the problems at the same time.Here we propose a novel hybrid electrolyte with Al^(3+)as additive to construct an aqueous ZIB composed of metallic zinc anode and K_(0.51)V_(2)O_(5)(KVO)nanoplate cathode.The highly reversible multistep K^(+)/Zn^(2+)-ions co-insertion/extraction in the lamellar structure with large interlayer spacing is clearly evidenced by systematical characterizations.In the presence of Al^(3+),the insulating basic zinc salts on the cathode surface have been reduced greatly,and the electrochemical potential window has been significantly expanded from 3 to 4.35 V.More interestingly,the Al^(3+)acts as a dopant embedded into the lattice that strengthens the crystal structure.Benefits from the suppressed zinc dendrite growth,the symmetrical Zn/Zn battery exhibited a satisfactory cycling life over 1,500 h at a high rate of 3 mA·cm^(-2)in the hybrid electrolyte.As a result,the Zn/KVO batteries delivered a high specific capacity of 210 mAh·g^(-1)and retained high capacity retention of 91%after 1,600 h at a low current of 100 mA·g^(-1).

Enhanced electrochemical property of FePO_4-coated LiNi_(0.5)Mn_(1.5)O_4 as cathode materials for Li-ion battery

Pristine LiNi0.5Mnl.5O4 and FePO4-coated one with Fd-3m space groups were prepared by a sol-gel method. The structure and performance were studied by X-ray diffraction （XRD） rietveld refinement, scanning electron microscopy （SEM）, high resolution transmission electron microscopy （HRTEM）, energy dispersive spectrometer （EDS） mapping, electrochemical impedance spectroscopy （EIS） and charge- discharge tests, respectively. The lattice parameters of all samples almost remain the same from the Rietveld refinement, revealing that the crystallographic structure has no obvious difference between pris- tine LiNi0.5Mn1.5O4 and FePO4-coated one. All materials show similar morphologies with uniform particle distribution with small particle size, and FePO4 coating does not affect the morphology of LiNi0.5Mnl05O 4 material. EDS mapping and HRTEM show that FePO4 may be successfully wrapped around the surfaces of LiNio.sMnl.s04 particles, and provides an effective coating layer between the electrolyte and the surface of LiNi0.5Mn1.5O4 particles. FePO4 （1 wt%）-coated LiNio.sMnl.504 cathode shows the highest discharge capac- ity at high rate （2 C） among all samples. After 80 cycles, the reversible discharge capacity of FePO4 （1 wt%） coated LiNi0.5Mn0.5O4 is 117 mAh g^-1, but the pristine one only has 50 mAh g^-1. FeP04 coating is an effec- tive and controllable way to stabilize the LiNi0.5Mn1.5O4/electrolyte interface, and avoids the direct con- tact between LiNi0.5Mn1.5O4 powders and electrolyte, then suppresses the side reactions and enhances the electrochemical performance of the LiNi0.5Mn1.5O4.