高校大型仪器开放实验室网络培训体系的探索

大型仪器在高校人才培养和科研测试服务中发挥着重要作用,系统的培训体系是高校大型仪器共享平台高效运行的基本保障,也是高校推进一流教育和拔尖人才培养的客观要求。系统性规范化的网络培训模式有利于提升培训的效果。通过构建包含安全培训及考核、仪器使用培训及考核、仪器原理及应用技巧、仪器测试成果与前沿展示互动交流于一体的网络资源平台,探索基于此平台的培训管理体系和长效完备的学习支撑体系,为高校大型仪器开放共享与人才培养体系建设提供了新思路。

Piezotronic neuromorphic devices:principle,manufacture,and applications

With the arrival of the era of artificial intelligence(AI)and big data,the explosive growth of data has raised higher demands on computer hardware and systems.Neuromorphic techniques inspired by biological nervous systems are expected to be one of the approaches to breaking the von Neumann bottleneck.Piezotronic neuromorphic devices modulate electrical transport characteristics by piezopotential and directly associate external mechanical motion with electrical output signals in an active manner,with the capability to sense/store/process information of external stimuli.In this review,we have presented the piezotronic neuromorphic devices(which are classified into strain-gated piezotronic transistors and piezoelectric nanogenerator-gated field effect transistors based on device structure)and discussed their operating mechanisms and related manufacture techniques.Secondly,we summarized the research progress of piezotronic neuromorphic devices in recent years and provided a detailed discussion on multifunctional applications,including bionic sensing,information storage,logic computing,and electrical/optical artificial synapses.Finally,in the context of future development,challenges,and perspectives,we have discussed how to modulate novel neuromorphic devices with piezotronic effects more effectively.It is believed that the piezotronic neuromorphic devices have great potential for the next generation of interactive sensation/memory/computation to facilitate the development of the Internet of Things,AI,biomedical engineering,etc.

湿热环境对复合材料单向板拉伸性能的影响

湿热环境会导致复合材料层合结构力学性能下降。针对[90]16和[0]16复合材料单向板,在不同湿热环境处理后进行拉伸试验,对比分析其拉伸性能退化情况,通过断口形貌及微观形貌分析阐述其退化机理。结果表明,干燥环境下,复合材料单向板中的环氧树脂基体在高温下发生后固化,[90]16单向板拉伸强度随环境温度升高而增加,[0]16单向板拉伸强度随环境温度上升基本不发生变化; 85%RH下,单向板纤维-基体界面上产生湿应力与热应力,[90]16和[0]16单向板拉伸强度均随环境温度升高而下降; 70℃水浴中,单向板的基体树脂与纤维-基体界面均发生严重损伤,[90]16和[0]16单向板拉伸强度严重下降。

湿热环境对CFRP层板压缩性能的影响

湿热环境对CFRP层板力学性能产生重要影响。通过加速吸湿试验研究T700/3228层板的吸湿特性,对比分析[0]16及[90]16层板经不同湿热环境处理后的性能退化情况,通过微观结构表征阐述其压缩退化机理。结果表明,随着温度及湿度升高,[90]16层板中的树脂基体在压缩载荷下发生的膨胀与热膨胀及湿膨胀叠加,导致[90]16层板的压缩强度下降;[0]16层板中的纤维在压缩载荷下倾向于随树脂基体发生局部屈曲变形,导致[0]16层板的压缩强度下降。

复合材料薄壁方管准静态轴向压缩失效机理及吸能特性

以[±45]3s铺层的碳纤维增强复合材料薄壁方管为对象,进行准静态轴向压缩试验,研究其轴向压缩失效模式及破坏吸能特性。试验结果表明,[±45]3s方管在准静态轴向压缩载荷作用下的破坏模式为局部屈曲失效模式;在局部屈曲区,失效主要表现为纤维与基体断裂、分层以及轴向与纵向裂纹扩展,并耗散大量能量;在弹性区,能量耗散大部分由于层间分层,少部分来自于纤维与基体弹性变形。基于Puck2000基体失效准则与Yamada Sun纤维失效准则,研究建立单层壳、多层壳、层合壳3种有限元模型,对方管轴向压缩失效模式和吸能特性进行模拟。仿真结果表明,3种有限元模型能够在一定程度上复现[±45]3s方管轴向压缩失效模式及吸能特性,但层合壳模型能够更好地模拟[±45]3s方管局部屈曲的失效模式,且比吸能误差最小,仿真结果与试验结果最接近。

P-doped BN nanosheets decorated graphene as the functional interlayer for Li–S batteries

Lithium–sulfur(Li–S)batteries have attracted much attention due to their ultrahigh theoretical specific capacity.However,serious capacity attenuation caused by shuttle effect still inhibits the performance improvement.Herein,a modified separator consists of the few-layer graphene as a highly conductive network and stable scaffold to support P-doped boron nitride(denoted as BN-P@GO)as the functional interlayer of Li–S batteries.The cell with the interlayer provides an initial discharge capacity as high as1045.3 mAh g^-1,and retains a high reversible capacity of 728.7 mAh g^-1 at 1 C after 500 cycles with a capacity decay of 0.061%per cycle.Moreover,the rate capability is also superior to cells with BN@GO or BN-P interlayers,i.e.reversible capcity of 457.9 mAh g^-1 even at 3 C.The excellent electrochemical performance is ascribed to the synergistic effect of physical barrier and chemical adsorption for dissolved polysulfides provided by the modified layer.Furhtermore,it also mitigates the polarization and promotes kinetic reactions of the cells.This work provides a concise and effective method for commercialization of lithium–sulfur batteries.

Formation of hierarchical Fe7Se8 nanorod bundles with enhanced sodium storage properties

Ordered hierarchical architectures are attractive candidates for electrochemical energy storage applications.Herein,a facile self-template strategy is applied to prepare Fe7Se8 architectures with a monolithic structure via a self-synthesized single precursor and subsequent calcination at high temperature.With the support of oleylamine,the precursor is structurally targeted to engineer the Fe7Se8 microstructure,featuring nanorod bundles arranged along the longitudinal direction.Because of their ordered hierarchical structure,the Fe7Se8 nanorod bundles deliver a high reversible capacity of 300 m Ah g^-1 at 0.5 A g^-1,along with exceptional rate capability up to 20 A g^-1 and long-term cycle life over 8000 cycles,which represents the highest stability of Fe7Se8 anodes for sodium-ion batteries reported to date.The feasibility of the present strategy to prepare metal selenide structures highlights its promising potential for the rational and effective engineering of electrode materials responsible for the electrochemical performance of energy storage systems.

N-doped carbon nanotubes formed in a wide range of temperature and ramping rate for fast sodium storage

Herein,nickel@nitrogen-doped carbon nanotubes(Ni@NCNTs)are prepared by a simple and reliable method with Ni-based complex as single-source precursor.Significantly,the formation of CNTs is not susceptible to the calcination temperature and ramping rate and Ni@NCNTs can be attained from 430 to 900℃in an inert atmosphere.Then they are the first time to be applied as the anode material for sodium-ion batteries.The presence of Ni nanoparticles(NPs)facilitates the solid electrolyte interface film over the anode surface and improves the capacity retention of the host material,especially at the high rates.Furthermore,Na+diffusion is reinforced after the introduction of Ni NPs.Ni@NCNTs obtained at 500℃(Ni@NCNTs-500)exhibit the best capacity retention and rate capability.Kinetics analyses demonstrate the faster electron transportation and ion diffusion than others prepared at other temperatures.The surficial capacitance storage favors the fast electrochemistry kinetics.It delivers a high specific capacity(192 mA h g^−1 at 0.5 A g^−1),excellent cycling stability(103 mA h g^−1 after 10,000 cycles at 10 A g^−1),and outstanding high-rate capability up to 20 A g^−1(118 mA h g^−1).The related full cells confirm a high energy density of 140 Wh kg^−1 at 38.16 W kg^−1 and 44.27 W h kg^−1 at 762 W kg^−1.

mproved Hydrogen Storage Properties of Ti_(23)V_(40)Mn_(37)Alloy Doped with Zr_(7)Ni_(10) by Rapid Solidification

As-cast and rapidly solidified Ti_(23)V_(40)Mn_(37)alloy doped with Zr_(7)Ni_(10) was synthesized by arc melting and melt-spinning.The microstructure,activation property,hydrogen absorption kinetics,and hydrogen absorption/desorption thermodynamics were investigated to evaluate a comprehensive hydrogen storage property of the alloys.Both preparation methods had a negligible effect on the lattice parameter of BCC and C14 Laves phases in the alloys.The alloy prepared by melt-spinning showed an increased proportion of BCC phase,larger hydrogen absorption capacity,faster hydrogen absorption rate,and higher hydrogen absorption/desorption platform pressure.The dehydriding enthalpy and endothermic peak temperature of the rapidly solidified alloy were 33.55±2.14 KJ/mol H_(2)and 526.2 K,respectively,which are smaller than those of the as-cast alloy.It indicates the decreased hydride stability and improved hydrogen desorption property.By contrast with the as-cast alloy,the rapidly solidified alloy showed a preferable comprehensive hydrogen storage property.

Ambipolar tribotronic transistor of MoTe_(2)

Two-dimensional(2D)tribotronic devices have been successfully involved in electromechanical modulation for channel conductance and applied in intelligent sensing system,touch screen,and logic gates.Ambipolar transistors and corresponding complementary inverters based on one type of semiconductors are highly promising due to the facile fabrication process and readily tunable polarity.Here,we demonstrate an ambipolar tribotronic transistor of molybdenum ditelluride(MoTe_(2)),which shows typical ambipolar transport properties modulated by triboelectric potential.It is comprised of a MoTe_(2)transistor and a lateral sliding triboelectric nanogenerator(TENG).The induced triboelectric potential by Maxwell’s displacement current(a driving force for TENG)can readily modulate the transport properties of both electrons and holes in MoTe_(2)channel and effectively drive the transistor.High performance tribotronic properties have been achieved,including low cutoff current below 1 pA·μm^(−1)and high current on/off ratio of~103 for holes and electrons dominated transports.The working mechanism on how to achieve tribotronic ambipolarity is discussed in detail.A complementary tribotronic inverter based on single flake of MoTe_(2)is also demonstrated with low power consumption and high stability.This work presents an active approach to efficiently modulate semiconductor devices and logic circuits based on 2D materials through external mechanical signal,which has great potential in human–machine interaction,intelligent sensor,and other wearable devices.

Enhancing kinetics of Li-S batteries by graphene-like N,S-codoped biochar fabricated in NaCl non-aqueous ionic liquid

Graphene-like N,S-codoped bio-carbon nanosheets(GNSCS) were prepared by a facile and environment-friendly NaCl non-aqueous ionic liquid route to house sulfur for lithium-sulfur battery. The natural nori powder was calcined at 900°C for 3 h under Ar, in which NaCl non-aqueous ionic liquid can exfoliate carbon aggregates into nanosheets. The structural characterization of GNSCS by a series of techniques demonstrates the graphene-like feature.When evaluated as the matrix for sulfur cathode, GNSCS/S exhibits more prominent cycling stability and rate capability.A discharge capacity of 548 mA h g-1 at a current density of 1.6 A g-1 after 400 cycles was delivered with a capacity fade rate of only 0.13% per cycle and an initial Coulombic efficiency(CE) as high as 99.7%. When increasing the areal sulfur loading up to 3 mg cm-2, the discharge capacity can still be retained at 647 mA h g-1 after more than 100 cycles with a low capacity degradation of only ~0.30% per cycle. The features of N/S dual-doping and the graphene-like structure are propitious to the electron transportation, lithium-ion diffusion and more active sites for chemically adsorbing polysulfides. It is anticipated that other functional biochar carbon can also be attained via the low-cost, sustainable and green method.

Carbon-coated mesoporous Co9S8 nanoparticles on reduced graphene oxide as a long-life and high-rate anode material for potassium-ion batteries

Carbon-coated mesoporous Co9S8 nanoparticles supported on reduced graphene oxide(rGO)are successfully synthesized by a simple process.This composite makes full use of the protection of the carbon layer on the surface,the good conductivity and three-dimensional(3D)structure of rGO,the mesoporous structure and nanoscale size of Co9S8,thereby presenting the excellent electrochemical performances in potassium-ion batteries,407.9 mAh·g^−1 after 100 cycles at 0.2 A·g^−1 and 215.1 mAh·g^−1 at 5 A·g^−1 in rate performances.After 1,200 cycles at 1.0 A·g^−1,this composite still remains a capacity of 210.8 mAh·g^−1.The redox reactions for potassium storage are revealed by ex-situ transmission electron microscope(TEM)/high-resolution TEM(HRTEM)images,selected area electron diffraction(SAED)patterns and X-ray photoelectron spectroscopy(XPS)spectra.The application of this composite as the host of sulfur for Li-S batteries is also explored.It sustains a capacity of 431.8 mAh·g^−1 after 800 cycles at 3 C,leading to a degradation of 0.052%per cycle.These results confirm the wide applications of this composite for electrochemical energy storage.

Bonding VSe2 ultrafine nanocrystals on graphene toward advanced lithium-sulfur batterie

Lithium–sulfur batteries have been attracting considerable research attention due to their high energy densities and low costs. However, one of their main challenges is the undesired shuttling of polysulfides, causing rapid capacity degradation. Herein, we report the first example of sulfiphilic VSe2 ultrafine nanocrystals immobilized on nitrogen-doped graphene to modify the battery separator for alleviating the shuttling problem. VSe2 nanocrystals provide numerous active sites for chemisorption of polysulfides as well as benefit the nucleation and growth of Li2S. Furthermore, the kinetic reactions are accelerated which is confirmed by higher exchange current density and higher lithium ion diffusion coefficient. And the first-principles calculations further show that the exposed sulfiphilic planes of VSe2 boost the redox of Li2S. When used as separators within the lithium sulfur batteries, the cell indicates greatly enhanced electrochemical performances with excellent long cycling stability and exceptional rate capability up to 8 C. Moreover, it delivers a higher areal capacity of 4.04 mAh·cm^−2 as well as superior cycling stability with sulfur areal loading up to 6.1 mg·cm^−2. The present strategy can encourage us in engineering novel multifunctional separators for energy-storage devices.

N,P-codoped graphene supported few-layered MoS2 as a long-life and high-rate anode materials for potassium-ion storage

Layer-structured MoS_(2)is regarded as a promising anode material for potassium ion batteries.Herein,MoS_(2)nanosheets on N,P-codoping reduced graphene oxide(MoS_(2)/N,P-rGO)have been successfully prepared via a facile two-step synthesis,where few-layered MoS_(2)nanosheets are chemically bonded onto the surface of N,P-rGO.As an anode material,MoS_(2)/N,P-rGO exhibits a high specific capacity(462.7 mAh·g^(-1)at 100 mA·g^(-1)over 200 cycles),outstanding rate capability(224.9 mAh·g^(-1)at 20 A·g^(-1)),and excellent cycle life(236.6 mAh·g^(-1)at 2 A·g^(-1)after 7,000 cycles),much better than those of MoS_(2)and MoS_(2)/rGO.These advanced performances outperform most of the reported anode materials for potassium ion batteries to date.Meanwhile,the K-storage reactions of MoS_(2)/N,P-rGO have been disclosed through in-situ and ex-situ characterizations.The kinetics analysis confirms that K-storage of MoS_(2)/N,P-rGO is predominant by pseudo-capacitance.

Synergistic Lewis acid-base sites of ultrathin porous Co_(3)O_(4)nanosheets with enhanced peroxidase-like activity

Surface Lewis acid-base sites in crystal structure may influence the physicochemical properties and the catalytic performances in nanozymes.Understanding the synergistic effect mechanism of Co_(3)O_(4)nanozymes towards substances(3,3’,5,5’-tetramethylbenzidine(TMB)and hydrogen peroxide(H2O2))induced by surface Lewis acid-base sites is important to enhance the efficiency for peroxidase-like reaction.Herein,ultrathin porous Co_(3)O_(4)nanosheets with abundant Lewis acid-base sites were prepared by sodium borohydride(NaBH4)reduction treatment,which exhibited high-efficiency peroxidase-like activity compared with original Co_(3)O_(4)nanosheets.The Lewis acid-base sites for ultrathin porous Co_(3)O_(4)nanosheets nanozyme were owing to the coordination unsaturation of Co ions and the formation of defect structure.Ultrathin porous Co_(3)O_(4)nanosheets had 18.26-fold higher catalytic efficiency(1.27×10^(-2)s^(-1)·mM^(-1))than that of original Co_(3)O_(4)(6.95×10^(-4)s^(-1)·mM^(-1))in oxidizing TMB substrate.The synergistic effect of surface acid and base sites can enhance the interfacial electron transfer process of Co_(3)O_(4)nanosheets,which can be a favor of absorption substrates and the generation of reactive intermediates such as radicals.Furthermore,the limit of detection of hydroquinol was 0.58μM for ultrathin porous Co_(3)O_(4)nanosheets,965-fold lower than original Co_(3)O_(4)(560μM).Besides,the linear range of ultrathin porous Co_(3)O_(4)nanosheets was widely with the concentration of 5.0-1,000μM.Colorimetric detection of hydroquinol by agarose-based hydrogel membrane was provided based on excellent peroxidase-like properties.This study provided insights into designing high-performance nanozymes for peroxidase-like catalysis via a strategy of solid surface acid-base sites engineering.

Hierarchical flower-like cobalt phosphosulfide derived from Prussian blue analogue as an efficient polysulfides adsorbent for long-life lithium-sulfur batteries

Lithium-sulfur (Li-S) battery as one of the most attractive candidates for energy storage systems has attracted extensive interests.Herein,for the first time,hierarchical flower-like cobalt phosphosulfide architectures (defined as "CoSP") derived from Prussian blue analogue (PBA) was fabricated through the conversion of Co-based PBA in PxSy atmosphere.The as-prepared polar CoSP could effectively trap polysulfides through the formation of strong chemical bonds.In addition,after the combination of CoSP with high conductive rGO,the obtained CoSP/rGO as sulfur host material exhibits ultralow capacity decay rate of 0.046% per cycle over 900 cycles at a current density of 1 C.The excellent performance could be attributed to the shortened lithium diffusion pathways,fastened electron transport ability during polysulfide conversion,and increased much more anchor active sites to polysulfides,which is expected to be a promising material for Li-S batteries.It is believed that the as-prepared CoSP/rGO architectures will shed light on the development of novel promising materials for Li-S batteries with high cycle stability.

Light-responsive color switching of self-doped TiO_(2-x)/WO_(3)·0.33H_(2)O hetero-nanoparticles for highly efficient rewritable paper

Smart materials that reversibly change color upon light illumination are widely explored for diverse appealing applications.However,light-responsive color switching materials are mainly limited to organic molecules.The synthesis of inorganic counterparts has remained a significant challenge because of their slow light response and poor reversibility.Here,we report a seeded growth strategy for the synthesis of TiO_(2-x)/WO_(3)·0.33H_(2)Ohetero-nanoparticles(HNPs)with networked wire-like structure of〜10 nm in diameters that enable the highly reversible light-responsive color switching properties.For the TiO_(2-x)/WO_(3)·0.33H_(2)OHNPs,T P species self-doped in TiO_(2-x)nanoparticles(NPs)act as efficient sacrificial electron donors(SEDs)and Ti-O-W linkages formed between TiO2-x and WO30.33H2O NPs ensure the nanoscale interfacial contact,endowing the HNPs enhanced photoreductive activity and efficient interfacial charge transfer upon ultraviolet(UV)illumination to achieve highly efficient color switching.The TiO_(2-x)/WO_(3)·0.33H_(2)OHNPs exhibits rapid light response(<15 s)and long reversible color switching cycles(>180 times).We further demonstrate the applications of TiO_(2-x)/WO_(3)·0.33H_(2)O HNPs in ink-free,light-printable rewritable paper that can be written on freehand or printed on through a photomask using UV light.This work opens an avenue for designing inorganic light-responsive color switching nanomaterials and their smart applications.

Integrated bioinformatics identifies the dysregulation induced by aberrant gene methylation in colorectal carcinoma

Colorectal carcinoma(CRC)is one of the most common cancers,and is associated with a poor dlinical outcome.The key genes and potential prognostic markers in colorectal carcinoma remain to be identfed and explored for clinical application.DNA expression/methyl-ation profles were downloaded from the Gene Expression Omnibus(GEO)database to identify differentially expressed/methylated genes(DEGs and DEMs).A total of 255 genes and 372 genes were identified as being up-regulated and down-regulated,respectively,in GSE113513,GSE81558,and GSE89076.There were a total of 3350 hypermethylated genes and 443 hypomethylated genes identifed in GSE 48684.Twenty genes were found to be hypermethylated as well as down-regulated,and a functional enrichment analysis revealed that these genes were mainly involved in cancer-related pathways.Among these 20 genes,GPM6A,HAND2 and C2orf40 were related to poor outcomes in cancer patients based on a survival analysis.Concurrent decreases of GPM6A,HAND2 and C2orf40 protein expression were observed in highly-dif ferentiated colorectal carcinoma tissues,and higher expression levels were found in undifferentiated or minimally-differentiated colorectal carcinoma tissues.In conclusion,20 genes were found to be downregulated and hypermethylated in CRC,among which GPM6A,HAND2 and C2orf40 were explored for their potential prognostic value.

Construction and electrochemical mechanism investigation of hierarchical core-shell like composite as high performance anode for potassium ion batteries

Potassium-ion batteries(PIBs)are promising candidates for next-generation energy storage devices due to the earth abundance of potassium,low cost,and stable redox potentials.However,the lack of promising high-performance electrode materials for the intercalation/deintercalation of large potassium ions is a major challenge up to date.Herein,we report a novel uniform nickel selenide nanoparticles encapsulated in nitrogen-doped carbon(defined as“NiSe@NC”)as an anode for PIBs,which exhibits superior rate performance and cyclic stability.Benefiting from the unique hierarchical core-shell like nanostructure,the intrinsic properties of metal-selenium bonds,synergetic effect of different components,and a remarkable pseudocapacitance effect,the anode exhibits a very high reversible capacity of 438 mA·h·g^(-1)at 50 mA·g^(-1),an excellent rate capability,and remarkable cycling performance over 2,000 cycles.The electrochemical mechanism were investigated by the in-situ X-ray diffraction,ex-situ high-resolution transmission electron microscopy,selected area electron diffraction,and first principle calculations.In addition,NiSe@NC anode also shows high reversible capacity of 512 mA·h·g^(-1)at 100 mA·g^(-1)with 84%initial Coulombic efficiency,remarkable rate performance,and excellent cycling life for sodium ion batteries.We believe the proposed simple approach will pave a new way to synthesize suitable anode materials for secondary ion batteries.

Molten Salt Derived Graphene-Like Carbon Nanosheets Wrapped SiO_(x)/Carbon Submicrospheres with Enhanced Lithium Storage

There is no doubt that SiO_(x) and carbon composite is one of the promising anode materials for lithium-ion batteries owing to its high capacity and rational cycling stability.Herein,we report a sol-gel synthesis followed by molten salt carbonization route to fabricate graphene-like carbon nanosheet wrapped SiO_(x)/C submicrospheres(SiO_(x)/C@2D-C).The in-situ generated carbon nanosheets under molten salt condition can further improve the electroconductivity,restrain the volumetric expansion and guarantee the structural integrity of the electrode.As a result,the as-obtained SiO_(x)/C@2D-C delivers a discharge capacity of 559 mAh·g^(-1) at 0.5 A·g^(-1) after 200 cycles and 548 mAh·g^(-1) at 1.0 A·g^(-1) even after 1000 cycles.The full cell assembled with SiO_(x)/C@2D-C as anode and commercial LiFeP0_(4) as cathode can achieve an energy density of 200 Wh·kg^(-1) and maintain a capacity of 66.7% after 100 cycles with a working potential of 2.8 V.The approach is simple and cost effective,which is promising for mass production of SiO_(x)-based materials for high energy LIBs.