The chance of sodium titanate anode for the practical sodium-ion batteries

Supporting sustainable green energy systems,there is a big demand gap for grid energy storage.Sodiumion storage,especially sodium-ion batteries(SIBs),have advanced significantly and are now emerging as a feasible alternative to the lithium-ion batteries equivalent in large-scale energy storage due to their natural abundance and prospective inexpensive cost.Among various anode materials of SIBs,beneficial properties,such as outstanding stability,great abundance,and environmental friendliness,make sodium titanates(NTOs),one of the most promising anode materials for the rechargeable SIBs.Nevertheless,there are still enormous challenges in application of NTO,owing to its low intrinsic electronic conductivity and collapse of structure.The research on NTOs is still in its infancy;there are few conclusive reviews about the specific function of various modification methods.Herein,we summarize the typical strategies of optimization and analysis the fine structures and fabrication methods of NTO anodes combined with the application of in situ characterization techniques.Our work provides effective guidance for promoting the continuous development,equipping NTOs in safety-critical systems,and lays a foundation for the development of NTO-anode materials in SIBs.

Dynamic characteristics of multi-span spinning beams with elastic constraints under an axial compressive force

A theoretical model for the multi-span spinning beams with elastic constraints under an axial compressive force is proposed.The displacement and bending angle functions are represented through an improved Fourier series,which ensures the continuity of the derivative at the boundary and enhances the convergence.The exact characteristic equations of the multi-span spinning beams with elastic constraints under an axial compressive force are derived by the Lagrange equation.The efficiency and accuracy of the present method are validated in comparison with the finite element method(FEM)and other methods.The effects of the boundary spring stiffness,the number of spans,the spinning velocity,and the axial compressive force on the dynamic characteristics of the multi-span spinning beams are studied.The results show that the present method can freely simulate any boundary constraints without modifying the solution process.The elastic range of linear springs is larger than that of torsion springs,and it is not affected by the number of spans.With an increase in the axial compressive force,the attenuation rate of the natural frequency of a spinning beam with a large number of spans becomes larger,while the attenuation rate with an elastic boundary is lower than that under a classic simply supported boundary.

Self-Adaptive and Electric Field-Driven Protective Layer with Anchored Lithium Deposition Enable Stable Lithium Metal Anode

Lithium metal battery has great development potential because of its lowest electrochemical potential and highest theoretical capacity.However,the uneven deposition of Li^(+)flux in the process of deposition and stripping induces the vigorous growth of lithium dendrites,which results in severely battery performance degradation and serious safety hazards.Here,the tetragonal BaTiO3 polarized by high voltage corona was used to build an artificial protective layer with uniform positive polarization direction,which enables uniform Li^(+)flux.In contrast to traditional strategies of using protective layer,which can guide the uniform deposition of lithium metal.The ferroelectric protective layer can accurately anchor the Li^(+)and achieve bottom deposition of lithium due to the automatic adjustment of the electric field.Simultaneously,the huge volume changes caused by Li^(+)migration change of the lithium metal anode during charging and discharging is functioned to excite the piezoelectric effect of the protective layer,and achieve seamless dynamic tuning of lithium deposition/stripping.This dynamic effect can accurately anchor and capture Li^(+).Finally,the layer-modified Li anode enables reversible Li plating/stripping over 1500 h at 1 mA cm^(-2)and 50℃in symmetric cells.In addition,the assembled Li-S full cell exhibits over 300 cycles with N/P≈1.35.This work provides a new perspective on the uniform Li^(+)flux at the Li-anode interface of the artificial protective layer.

Material decomposition of spectral CT images via attention-based global convolutional generative adversarial network

Spectral computed tomography(CT)based on photon counting detectors can resolve the energy of every single photon interacting with the sensor layer and be used to analyze material attenuation information under different energy ranges,which can be helpful for material decomposition studies.However,there is a considerable amount of inherent quantum noise in narrow energy bins,resulting in a low signal-to-noise ratio,which can consequently affect the material decomposition performance in the image domain.Deep learning technology is currently widely used in medical image segmentation,denoising,and recognition.In order to improve the results of material decomposition,we propose an attention-based global convolutional generative adversarial network(AGC-GAN)to decompose different materials for spectral CT.Specifically,our network is a global convolutional neural network based on an attention mechanism that is combined with a generative adversarial network.The global convolutional network based on the attention mechanism is used as the generator,and a patchGAN discriminant network is used as the discriminator.Meanwhile,a clinical spectral CT image dataset is used to verify the feasibility of our proposed approach.Extensive experimental results demonstrate that AGC-GAN achieves a better material decomposition performance than vanilla U-Net,fully convolutional network,and fully convolutional denseNet.Remarkably,the mean intersection over union,structural similarity,mean precision,PAcc,and mean F1-score of our method reach up to 87.31%,94.83%,93.22%,97.39%,and 93.05%,respectively.

Deciphering the degradation discrepancy in Ni-rich cathodes with a diverse proportion of[003]crystallographic textures

The crystal plane plays a very important role in the properties of Ni-rich cathodes.[003]crystallographic texture regulation has been proven to improve structural stability,and yet,the discrepancy of particles with different exposed ratios of[003]in structural attenuation has not been clarified.Herein,we have unraveled comprehensively the structural decay difference for Ni-rich cathodes’primary particles with the different percentages of exposed[003]by regulating the precursor coprecipitation process.The findings based on structural characterization,first-principles calculations,finite element analysis,and electrochemical test reveal that the length and width of particles represent[110]and[003]directions,respectively,and show that cathode particles with a higher[110]/[003]ratio can effectively inhibit structure degradation and intergranular/intragranular crack formation owing to the low oxygen vacancy formation energy on(003)planes and the small local stress on secondary/primary particles.This study may provide guidance for the structural design of layered cathodes.

Neuro-bone tissue engineering:emerging mechanisms,potential strategies,and current challenges

The skeleton is a highly innervated organ in which nerve fibers interact with various skeletal cells.Peripheral nerve endings release neurogenic factors and sense skeletal signals,which mediate bone metabolism and skeletal pain.In recent years,bone tissue engineering has increasingly focused on the effects of the nervous system on bone regeneration.Simultaneous regeneration of bone and nerves through the use of materials or by the enhancement of endogenous neurogenic repair signals has been proven to promote functional bone regeneration.Additionally,emerging information on the mechanisms of skeletal interoception and the central nervous system regulation of bone homeostasis provide an opportunity for advancing biomaterials.However,comprehensive reviews of this topic are lacking.Therefore,this review provides an overview of the relationship between nerves and bone regeneration,focusing on tissue engineering applications.We discuss novel regulatory mechanisms and explore innovative approaches based on nerve–bone interactions for bone regeneration.Finally,the challenges and future prospects of this field are briefly discussed.

负载铂聚磷腈微球对硅橡胶复合材料阻燃及陶瓷化性能的影响

以甲基乙烯基硅橡胶为基体,玻璃粉、白炭黑、云母、氢氧化镁、氢氧化铝为无机填料,负载铂聚磷腈微球(Pt/PZS)为催化协效剂,制备了阻燃型陶瓷化硅橡胶复合材料,研究了Pt/PZS的加入对阻燃硅橡胶复合材料热降解性能、阻燃性能及陶瓷化的影响。热重分析结果表明,极微量Pt/PZS微球(0.01 phr)的加入即可显著提高硅橡胶复合材料的热稳定性和成炭性,最大热失重温度提高60℃;锥形量热测试结果表明,Pt/PZS微球的加入可使材料热释放总量降低49.8%,热释放速率峰值降低67.0%;经500~900℃不同温度烧蚀后,试样形貌可以更好地保持,并且弯曲强度从0.1 MPa增大到2.1 MPa,提高了20倍。通过扫描电镜分析发现,随烧蚀温度的提高,复合体系出现了更明显的连续网状结构陶瓷相,说明Pt/PZS微球有显著促进阻燃硅橡胶陶瓷化的效应。

利用CRISPR/Cas9系统构建FGF21基因敲除小鼠模型

成纤维细胞生长因子(fibroblast growth factors,FGFs)是细胞间的多功能信号分子,调节生物体的多种生理功能。FGF21作为一种重要的调控因子,对毛囊发育及生长周期具有重要作用。为研究FGF21基因对毛囊发育及生长周期的影响及作用机制,本研究通过构建靶向敲除FGF21基因的载体,体外将Cas9 m RNA和g RNA显微注射到FVB小鼠受精卵中,在小鼠FGF21基因的第1外显子上造成移码突变,从而获得FGF21基因敲除(knock out,KO)小鼠。通过测序鉴定F0代小鼠基因型,共获得3只FGF21等位基因敲除小鼠(Fgf21^(-/-));q RT-PCR和Western blotting结果表明,在Fgf21^(-/-)小鼠中未检测到FGF21 m RNA表达和FGF21蛋白表达;经脱毛再生及皮肤组织H&E染色发现,与野生型(wild type,WT)小鼠相比,Fgf21^(-/-)小鼠体重降低、器官组织未出现异常变化、毛发生长速度减慢、毛囊的直径和毛发的密度均减小。本研究利用CRISPR/Cas9技术成功构建了Fgf21^(-/-)小鼠模型,为后续研究FGF21基因在毛囊发育及生长周期中的功能提供了更好的动物模型。

3D hierarchically porous NiO/Graphene hybrid paper anode for long-life and high rate cycling flexible Li-ion batteries

With the rapid emergence of wearable devices, flexible lithium-ion batteries(LIBs) are much more needed than ever. Free-standing graphene-based composite paper electrodes with various active materials have appealed wide applications in flexible LIBs. However, due to the prone-to-restacking feature of graphene layers, a long cycle life at high current densities is rather difficult to be achieved. Herein, a unique threedimensional(3D) hierarchically porous NiO micro-flowers/graphene paper(fNiO/GP) electrode is successfully fabricated. The resulting fNiO/GP electrode shows superior long-term cycling stability at high rates(e.g., storage capacity of 359 mAh/g after 600 cycles at a high current density of 1 A/g). The facile 3D porous structure combines both the advantages of the graphene that is highly conductive and flexible to ensure rapid electrons/ions transfer and buffer the volume expansion of NiO during charge/discharge,and of the micro-sized NiO flowers that induces hierarchical between-layer pores ranging from nanomicro meters to promote the penetration of the electrolyte and prevent the re-stacking of graphene layers. Such structural design will inspire future manufacture of a wide range of active materials/graphene composite electrodes for high performance flexible LIBs.

cgVEGF164基因对小鼠毛囊生长的影响

血管内皮生长因子(vascular endothelial growth factor, VEGF)是一种二聚体糖蛋白,能够诱导毛囊血管内皮细胞的增殖和迁移,调节毛囊周围毛细血管生成,进而影响毛囊的生长发育。已知cgVEGF164是绒山羊VEGF-A基因的一种主要剪接变体,但cgVEGF164基因是否具有调控毛囊生长发育的作用目前尚不清楚。为初步探究cgVEGF164基因对毛囊生长的影响及其机制,本研究通过原核显微注射制备cgVEGF164转基因过量表达小鼠。通过HE染色法比较转基因小鼠和非转基因对照小鼠毛囊的直径和密度,利用WesternBlot检测小鼠背部皮肤中信号蛋白ERK1/2、AKT1、LEF1的磷酸化水平。本研究成功获得5只阳性cg VEGF164转基因小鼠(雌雄比为4:1,阳性率8.5%);与非转基因对照小鼠相比,转基因小鼠毛囊直径增大、密度增加;经检测转基因小鼠中ERK1/2、AKT1、LEF1的磷酸化水平均上调。结果表明,cgVEGF164基因具有促进小鼠毛囊生长的作用,推测该功能可能与cgVEGF164影响ERK1/2、AKT1和LEF1等信号蛋白的磷酸化有关。

Tuning redox activity through delithiation induced protective layer and Fe-O coordination for Li-rich cathode with improved voltage and cycle performance

Li-rich layered transition metal oxides are one of the most promising cathode materials for their high energy density.However,the cathodes usually suffer from severe potential dropping and capacity fading during cycling,which are associated with the surface oxygen release and accompanied by cation densification and structural collapse.Herein,an integrative approach of simultaneous constructing uniform 3d Fe-ion doping in the transition metal layer and Li-rich Li_(5)FeO_(4) shell to grab the oxygen and prevent interfacial side reactions is proposed.The introduction of Fe induces higher redox potential and stronger 3 d Fe-O_(2)p covalent bond,triggering reversible anionic redox via a reductive coupling mechanism.And the delithiated product of Li-rich Li_(5)FeO_(4) not only acts as a protective layer alleviating the side reactions but also enhances the surface kinetic property.With the benefit of promoted reversibility of oxygen redox and enhanced surface stability,the cathode exhibits high reversible capacity and superior cycle performance.Density function theory calculation indicates that the O_(2)p non-bonding state in the cathode incorporated with Fe sits at a lower energy band,resulting in higher energy storage voltage and improved oxygen stability.Consequently,the modified cathode exhibits a discharge specific capacity of 307 m A h g^(-1)(1 C=250 m A g^(-1)),coulombic efficiency of 82.09%in the initial cycle at 0.1 C and 88.34%capacity retention after 100 cycles at 1 C.The work illustrates a strategy that could simultaneously enhance oxygen redox reversibility and interface stability by constructing lattice bond coordination and delithiation induced protective layer to develop Li-rich materials with high reversible capacity and long lifespan.

Fe-Nx Sites enriched microporous carbon nanoflower planted with tangled bamboo-like carbon nanotube as a strong polysulfides anchor for lithium-sulfur batteries

Serious shuttle effect and sluggish conversion kinetics of lithium polysulfides(LiPSs)have a massive impact on obstructing the practical application of lithium-sulfur(Li-S)batteries.To address such issues,Fe-Nx sites enriched microporous nanoflowers planted with tangled bamboo-like carbon nanotubes(Fe-Nx-C/Fe_(3)C-CNTs NFs)are found to be effective catalytic mediators with strong anchoring capabilities for LiPSs.The bamboo-like carbon nanotubes catalyzed by Fe_(3)C/Fe entangled each other to form a conductive network,which encloses a flowerlike microporous carbon core with embedded well-dispersed Fe-Nx active sites.As expected,electrons smoothly transfer along the dense conductive bamboo-like carbon network while the flower-like carbon core consisting of micropores induces the homogeneous distribution of tiny sulfur and favors the lithium ions migration with all directions.Meanwhile,Fe-Nx sites strongly trap long-chain LiPSs with chemical anchoring,and catalyze the redox conversion of LiPSs.Due to the aforementioned synergistic effects,the S@Fe-Nx-C/Fe_(3)C-CNTs NFs cathode exhibited a remarkable specific capacity(635 mAh g_(s)^(-1))at 3 C and a favorable capacity decay with 0.04%per cycle even after 400 cycles at 1 C.

The correlative analysis of myocardial strain and torsion and quantitative heart function scores in patients with coronary heart disease after PTCA

Objective To assess the relationship of myocardial strain and torsion and quantitative heart function scores in patients with coronary heart disease after PTCA.Methods A total of 90 patients with coronary artery disease after PTCA were randomly divided into clinically normal heart function group(group A,n=43)and abnormal heart function group(group B,n=47),and 30 healthy people matched with age and gender as the control group(group C,n=30).

Is it universal that the layered-spinel structure can improve electrochemical performance?

The introduction of spinel phase to form the layered-spinel structure(LSS)is an effective way to improve the electrochemical performance of Li-and Mn-rich layered oxides(LMR).But is this structure universal for all LMR systems?In this work,different Mn/Ni ratio systems with the LSS are discussed in detail.It is found that,high discharge capacity(200.8 mA h g^(-1) at 1C rate;1C=250 mA h g^(-1))as well as high capacity-retention(94%at 1C rate after 100 cycles)can be achieved by forming the LSS for low-Ni system(Mn/Ni=5.0).However,the capacity retention decreases severely in the high-Ni system(Mn/Ni=3.5,2.6).For example,when the ratio of Mn/Ni is 3.5,the capacity-retention of the layered-spinel sample was only 65.8%,compared to the 83%of the original LMR sample.The Ex-situ XRD,XPS,and HRTEM results demonstrate that the introduction of spinel phase in high-Ni system accelerates the transition and collapse of the crystal structure.This work provides guidance for optimizing the proportions of elements and the design of structures for the LMR.

Efficient Chemical Prelithiation with Modificatory Li^(+) Solvation Structure Enabling Spatially Homogeneous SEI toward High Performance SiO_(x) Anode

Chemical prelithiation is widely proven to be an effective strategy to address the low initial coulombic efficiency(ICE)of promising SiO_(x) anode.Though the reagent composition has been widely explored,the Li^(+) solvation structure,which practically plays the cornerstone role in the prelithiation ability,rate,uniformility,has rarely been explored.A novel environmentally-friendly reagent with weak solvent cyclopentyl methyl ether(CPME)is proposed that enables both improved ICE and spatial homogeneous solid electrolyte interphase(SEl).And the prelithiation behavior and mechanism were explored focused on the Li^(+) solvation structure.Both theoretical investigation and spectroscopic results suggest that weak solvent feature of CPME reduces the solvent coordination number and decreases the Li^(+) desolvation energy.

A parathyroid hormone related supramolecular peptide for multi-functionalized osteoregeneration

Supramolecular peptide nanofiber hydrogels are emerging biomaterials for tissue engineering,but it is difficult to fabricate multi-functional systems by simply mixing several short-motif-modified supramolecular peptides because relatively abundant motifs generally hinder nanofiber cross-linking or the formation of long nanofiber.Coupling bioactive factors to the assembling backbone is an ideal strategy to design multi-functional supramolecular peptides in spite of challenging synthesis and purification.Herein,a multi-functional supramolecular peptide,P1R16,is developed by coupling a bioactive factor,parathyroid hormone related peptide 1(PTHrP-1),to the basic supramolecular peptide RADA16-I via solid-phase synthesis.It is found that P1R16 self-assembles into long nanofibers and co-assembles with RADA16-I to form nanofiber hydrogels,thus coupling PTHrP-1 to hydrogel matrix.P1R16 nanofiber retains osteoinductive activity in a dose-dependent manner,and P1R16/RADA16-I nanofiber hydrogels promote osteogenesis,angiogenesis and osteoclastogenesis in vitro and induce multi-functionalized osteoregeneration by intramembranous ossification and bone remodeling in vivo when loaded to collagen(Col)scaffolds.Abundant red blood marrow formation,ideal osteointegration and adapted degradation are observed in the 50%P1R16/Col scaffold group.Therefore,this study provides a promising strategy to develop multi-functional supramolecular peptides and a new method to topically administrate parathyroid hormone or parathyroid hormone related peptides for non-healing bone defects.

Unveiling the correlation between structural alterations and enhanced high-voltage cyclability in Na-deficient P3-type layered cathode materials via Li incorporation

With exceptional capacity during high-voltage cycling,P3-type Nadeficient layered oxide cathodes have captured substantial attention.Nevertheless,they are plagued by severe capacity degradation over cycling.In this study,tuning and optimizing the phase composition in layered oxides through Li incorporation are proposed to enhance the high-voltage stability.The structural dependence of layered Na_(2/3)LixNi_(0.25)Mn_(0.75)O_(2)þδoxides on the lithium content(0.0≤x≤1.0)offered during synthesis is investigated systematically on an atomic scale.Surprisingly,increasing the Li content triggers the formation of mixed P2/O3-type or P3/P2/O3-type layered phases.As the voltage window is 1.5-4.5 V,P3-type Na2/3Ni_(0.25)Mn_(0.75)O_(2)(NL0.0NMO,R3m)material exhibits a sequence of phase transformations throughout the process of(de)sodiation,that is,O3⇌P3⇌O30⇌O3″.Such complicated phase transitions can be effectively suppressed in the Na2/3Li_(0.7)Ni_(0.25)Mn_(0.75)O_(2.4)(NL_(0.7)NMO)oxide with P2/P3/O3-type mixed phases.Consequently,cathodes made of NL0.7NMO exhibit a substantially enhanced cyclic performance at high voltages compared to that of the P3-type layered NL0.0NMO cathode.Specifically,NL0.7NMO demonstrates an outstanding capacity retention of 98%after 10 cycles at 1 C within 1.5-4.5 V,much higher than that of NL0.0NMO(83%).This work delves into the intricate realm of bolstering the high-voltage durability of layered oxide cathodes,paving the way for advanced sodium-ion battery technologies.

Damage mechanisms and recent research advances in Ni-rich layered cathode materials for lithium-ion batteries

Nickel-rich cathode is considered to be the cathode material that can solve the short-range problem of electric vehicles with excellent elec-trochemical properties and low price.However,microcracks,lithium–nickel hybridization,and irreversible phase transitions during cycling limit their commercial applications.These issues should be resolved by modifications.In recent years,it has been favored by researchers to solve a large number of problems by combining multiple modification strate-gies.Therefore,this paper reviews recent developments in various modification techniques for nickel-rich cathode materials that have improved their electrochemical characteristics.The summary of multiple modifications of nickel-rich materials will play a guiding role in future development.

全媒体时代新的社会阶层人士思想工作研究

全媒体时代,网络媒体应用越来越倾向于政治化、权力化。新的社会阶层人士与网络媒体之间具有先天性联系,是影响社会舆论的重要力量。全面准确把握新的社会阶层人士思想状况,是做好新时代统战工作的基本前提和必然要求。面对对象范围扩大化、思想引领复杂化、政治参与网络化等重大变化,传统统战工作格局的不适应性开始显现。做好全媒体时代新的社会阶层人士统战工作,需要转变工作理念,紧紧抓住传统媒体与新兴媒体深度融合发展的重要窗口期,由消极被动地适应转变为积极主动地引导,探索思想引领的有效对策,形成网上网下同心圆,不断巩固壮大共同奋斗的思想政治基础。

Active plane modulation of Bi_(2)O_(3)nanosheets via Zn substitution for efficient electrocatalytic CO_(2)reduction to formic acid

Formic acid is considered one of the most economically viable products for electrocatalytic CO_(2)reduction reaction(CO_(2)RR).However,developing highly active and selective electrocatalysts for effective CO_(2)conversion remains a grand challenge.Herein,we report that structural modulation of the bismuth oxide nanosheet via Zn^(2+)cooperation has a profound positive effect on exposure of the active plane,thereby contributing to high electrocatalytic CO_(2)RR performance.The obtained Zn-Bi_(2)O_(3)catalyst demonstrates superior selectivity towards formate generation in a wide potential range;a high Faradaic efficiency of 95%and a desirable partial current density of around 20 mA·cm^(-2)are obtained at−0.9 V(vs.reversible hydrogen electrode(RHE)).As proposed by density functional theory calculations,Zn substitution is the most energetically feasible for forming and stabilizing the key OCHO*intermediate among the used metal ions.Moreover,the more negative adsorption energy of OCHO*and the relatively low energy barrier for the desorption of HCOOH*are responsible for the enhanced activity and selectivity.