Sandwich-like structure C/SiO_(x)@graphene anode material with high electrochemical performance for lithium ion batteries

Silicon suboxide(SiO_(x),0<x<2)is recognized as one of the next-generation anode materials for high-energy-density lithium ion batteries(LIBs)due to its high theoretical specific capacity and abundant resource.However,the severe mechanical instability arising from large volume variation upon charge/discharge cycles frustrates its electrochemical performance.Here we propose a well-designed sandwich-like structure with sandwiched SiO_(x) nanoparticles between graphene sheets and amorphous carbon-coating layer so as to improve the structural stability of SiO_(x) anode materials during cycling.Graphene sheets and carbon layer together construct a three-dimensional conductive network around SiO_(x) particles,which not only improves the electrode reactions kinetics,but also homogenizes local current density and thus volume variation on SiO_(x) surface.Moreover,Si-O-C bonds between SiO_(x) and graphene endow the strong particle adhesion on graphene sheets,which prevents SiO_(x) peeling from graphene sheets.Owing to the synergetic effects of the structural advantages,the C/SiO_(x)@graphene material exhib-its an excellent cyclic performance such as 890 mAh/g at 0.1 C rate and 73.7%capacity retention after 100 cycles.In addition,it also delivers superior rate capability with a capacity recovery of 886 mAh/g(93.7%recovery rate)after 35 cycles of ascending steps at current range of 0.1-5 C and finally back to 0.1 C.This study provides a novel strategy to improve the structural stability of high-capacity anode materials for lithium/sodium ion batteries.

Bandgaps and vibration isolation of local resonance sandwich-like plate with simply supported overhanging beam

The concept of local resonance phononic crystals proposed in recent years provides a new chance for theoretical and technical breakthroughs in the structural vibration reduction.In this paper,a novel sandwich-like plate model with local resonator to acquire specific low-frequency bandgaps is proposed.The core layer of the present local resonator is composed by the simply supported overhanging beam,linear spring and mass block,and well connected with the upper and lower surface panels.The simply supported overhanging beam is free at right end,and an additional linear spring is added at the left end.The wave equation is established based on the Hamilton principle,and the bending wave bandgap is further obtained.The theoretical results are verified by the COMSOL finite element software.The bandgaps and vibration characteristics of the local resonance sandwich-like plate are studied in detail.The factors which could have effects on the bandgap characteristics,such as the structural damping,mass of vibrator,position of vibrator,bending stiffness of the beam,and the boundary conditions of the sandwich-like plates,are analyzed.The result shows that the stopband is determined by the natural frequency of the resonator,the mass ratio of the resonator,and the surface panel.It shows that the width of bandgap is greatly affected by the damping ratio of the resonator.Finally,it can also be found that the boundary conditions can affect the isolation efficiency.

High-performance asymmetric supercapacitors based on reduced graphene oxide/polyaniline composite electrodes with sandwich-like structure

The sandwich-like structure of reduced graphene oxide/polyaniline （RGO/PANI） hybrid electrode was prepared by electrochemical deposition. Both the voltage windows and electrolytes for electrochemical deposition of PANI and RGO were optimized. In the composites, PANI nanofibers were anchored on the surface of the RGO sheets, which avoids the re-stacking of neighboring sheets. The R（;O/PANI composite electrode shows a high specific capacitance of 466 F/g at 2 mA/cm2 than that of previously reported RGO/PANI composites. Asymmetric flexible supercapacitors applying RGO/PANI as positive electrode and carbon fiber cloth as negative electrode can be cycled reversibly in the high-voltage region of 0-1.6 V and displays intriguing performance with a maximum specific capacitance of 35.5 mF cm^-2. Also, it delivers a high energy density of 45.5 mW h cm^-2 at power density of 1250 mW cm^-2. Furthermore, the asymmetric device exhibits an excellent long cycle life with 97.6Z initial capacitance retention after 5000 cycles. Such composite electrode has a great potential for applications in flexible electronics, roll-up display, and wearable devices.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

2D sandwich-like nanosheets of ultrafine Sb nanoparticles anchored to graphene for high-efficiency sodium storage

Sb is considered a promising anode material for high-performance sodium-ion batteries （NIBs） owing to its high theoretical specific capacity （660 mAh-g-1）. However, Sb shows a very large volume change （-200%） during sodiation and desodiation, leading to poor electrochemical performance. Here, we designed and tested a sandwich-like graphene-supported Sb nanocomposite （denoted Sb@RGO@Sb）, in which ultrafine Sb nanoparticles are uniformly anchored on a reduced graphene oxide （RGO） surface. The ultrafine Sb nanocrystals anchored on the RGO surface minimize the aggregation of Sb and inhibit restacking of the RGO sheets, leading to a minimum transport length for both ions and electrons. The graphene layer not only accommodates the large volume variation of Sb during cycling but also promotes the electron conductivity of the whole electrode. Owing to its unique structure, this sandwich-like composite exhibits superior sodium storage properties.

Sandwich-like chitosan porous carbon Spheres/MXene composite with high specific capacitance and rate performance for supercapacitors

The application of porous carbon microspheres derived from pure biomass in supercapacitors is restricted due to their limited reactive groups.MXene owns a combination of redox Faradic surface with good metallic conductivity and hydrophilicity,which assists to obtain high pseudocapaci-tance and energy density.Herein,Ti_(3)C_(2)T_(x)MXene was introduced to chitosan-based porous carbon microsphere(CPCM)to fabricated sandwich-like structure(CPCM/MXene)through electrostatic interaction.The Ti_(3)C_(2)T_(x)protected the spherical structure of CPCM.Meanwhile,CPCM hindered the reaggregation of Ti_(3)C_(2)T_(x)by inserting in the Ti_(3)C_(2)T_(x)layers,promoting the electrolyte migra-tion kinetics.The synergistic effect endowed CPCM/MXene high specific capacitance of 362 F/g at current density of 0.5 A/g and acceptable cycling stability with 93.87%capacitance retention at a high current density of 10 A/g after 10,000 cycles.Furthermore,CPCM/MXene displayed a high energy density of 27.8 W/(h•kg)at 500.0 W/kg of power density.These satisfactory perfor-mances prove that combining Ti_(3)C_(2)T_(x)MXene nanosheets with porous carbon microspheres is a considering method to construct a new generation electrode material of supercapacitor.

Uniaxial tensile deformation behavior of a sandwich-like structural TiNb-NiTi composite for biomedical applications

The uniaxial tensile deformation behavior of a sandwich-like structural TiNb-NiTi composite was investigated by uniaxial tensile test and in situ high-energy synchrotron X-ray diffraction(SXRD).It is found that below 1.2%macroscopic strains,the elastic deformations of the B2,β,B19'andα"phases take place in the TiNbNiTi composite.During the subsequent loading,theβ→α"and B2→B19'stress-induced martensitic transformations(SIMTs)occur within the macroscopic strains of 0.5%-4.2%and the macroscopic strains of 0.7%-6.2%,respectively.At the macroscopic strain of about 4.2%,the outer TiNb layer of the TiNb-NiTi composite experiences a partial fracture,as proved by the disappearance of(040)_(α")and a sudden jump in the(110)_(B19')d-spacing caused by load transfer.With further uniaxial tensile deformation,the TiNbNiTi composite finally fractures at a strain of~6.2%.Our results might provide some valuable information for understanding the deformation behavior of novel sandwich-like structural shape memory composites in more depth.

Super-assembled sandwich-like Au@MSN@Ag nanomatrices for high-throughput and efficient detection of small biomolecules

Small biomolecules(m/z<500)are the material basis of organisms and participate in life activities,but their comprehensive and accurate detection in complex samples remains a challenge.Matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS)is a powerful detection tool for molecular analysis with high throughput.The development of a new matrix is essential to improve the efficiency of the MALDI-MS for molecular compound detection.In this work,the sandwich-like gold nanoparticles@mesoporous silica nanocomposite@silver nanoparticles(Au@MSN@Ag)nanospheres were prepared by layer-by-layer super-assembly strategy,and can be used as a novel matrix for the quantitative detection and enrichment of small biomolecules by LDI-MS.The sandwich-like nanospheres form a unique plasma resonant cavity that effectively absorbs the laser energy,while the homogeneous mesoporous structure of MSN can lock the analyte,which is essential for efficient LDI of small molecules.Compared to traditional matrices,Au@MSN@Ag shows the advantages of low background,wide application range,high sensitivity,super high salt and protein tolerance,and good stability.For example,the detection limit of glucose was as low as 5 fmol,and showed a good linear relationship in the range of 1−750μg/mL.Au@MSN@Ag assisted LDI-MS allows the enrichment and detection of small molecules in traditional Chinese medicine(TCM)without derivatization and purification,classification of herbs using the accurate quantitative results oligosaccharides,and identification of gelatin by amino acid content.This research could help in designing more efficient nanostructure matrices and further explored the application of LDI-MS.

古气候恢复及其对沉积的控制作用——以四川盆地上三叠统须家河组为例

四川盆地上三叠统须家河组是盆地的主力产层,该组发育的6段地层表现为砂—泥间互的"三明治"式沉积结构。为了探讨古气候对这种沉积结构的控制作用,文章首次利用孢粉学方法、元素比值法和自然伽马曲线法分别恢复了四川盆地晚三叠世须家河期各段地层沉积时期的古气候。孢粉植被法识别出蕨类和裸子类孢粉化石共计78属,呈现"拟网叶蕨孢属—凹边孢属—苏铁粉属"的须家河组孢粉组合特色,这种孢粉组合反映温暖潮湿的热带、亚热带气候类型。元素比值法中的钙镁比和锶钡比分别反映古温度和古盐度(古湿度),其中,钙镁比值与古温度正相关,锶钡比值与古盐度正相关而与古湿度负相关。自然伽马值是反映气候的又一种方法,GR值高代表古气候潮湿、沉积水体深;反之亦然。在孢粉法恢复的气候背景上,元素比值法和自然伽马曲线法反映了各段地层沉积时期的气候变化细节。综合三种方法的结果,认为:须家河组沉积于温暖潮湿的热带亚热带环境,须1、3、5段沉积时期,气候炎热潮湿;须2、4、6段沉积时期,气候温和干燥。须5段地层最为炎热潮湿,须2段地层最为温和干爽。受控于这种周期性的温、湿度升降,须家河组奇数段地层以泥质沉积为主,偶数段地层以砂质沉积为主,从而形成了砂泥间互的"三明治"式沉积结构,这样"近水楼台先得月"的源储搭配关系为油气成藏提供了有利条件。

基于4-二苯基乙酸及1,3-二(4-吡啶基)丙烷的两个银配合物的结构和荧光(英文)

以同物质的量比例的4-二苯基乙酸(Hbpa)、1,3-二(4-吡啶基)丙烷(bpp)和[Ag(NH3)](OH),在不同反应条件下制备了2个基于柔性配体的类三明治配合物{[Ag2(bpa)2(bpp)2]·2H2O}n(1)和{[Ag(bpa)(bpp)]·2H2O}n(2),对其进行了单晶结构、元素分析、红外光谱、荧光光谱和粉末衍射表征。结构表明1是由T型配位的银离子和Ag…Ag超分子作用组装而成的二维配合物;配合物2则是由四面体构型银离子和π…π堆积作用组装的二维配位超分子。此外,1和2还可在可见光区的不同位置发射较强荧光。

石墨烯支撑三明治结构材料的可控合成及其在能量存储与转换中的应用（英文）

综述了石墨烯支撑三明治结构材料的可控合成及其在能量存储与转换中应用的研究进展。基于不同的微观结构,石墨烯支撑三明治结构的材料主要分为如下三类:石墨烯支撑的纳米粒子(0D),石墨烯支撑的纳米棒、纳米线及纳米带(1D),石墨烯支撑的纳米片(2D)。在这些复合材料中,石墨烯与相应功能材料间本征不相容的问题不仅得到有效解决,而且石墨烯可以作为电子传输的快速通道,有利于其能量存储与转换过程。本文为石墨烯或者类石墨烯材料支撑三明治结构复合材料的设计与合成提供了思路,这种具有特定结构的材料潜在广泛应用于催化、传感器、能量存储与转换等领域。

丹池成矿带五圩矿集区矿床地质特征及构造成矿分析——以箭猪坡矿床为例

根据岩层能干性特征,五圩矿集区整体结构为两"强"夹一"弱"的"三明治"岩层结构,以箭猪坡最为典型,赋矿层位为弱能干性泥岩层。通过对箭猪坡矿床脉状矿体构式和平面、剖面矿脉展布特征的观察和分析,判断矿体形成于印支早期脆—韧性逆冲剪切带中,矿脉呈雁列状向深部倾伏,之后受印支晚期断展褶皱和燕山期SN向褶皱叠加、改造,最终使矿脉走向为NNW、剖面呈正"八"字形分布。矿脉直接受脆—韧性逆冲剪切带分布范围的控制。由此推断,具备"三明治"岩层结构的丹池成矿带内,在中间的泥岩层内均可能赋存脆—韧性剪切带控制的脉状矿体。

Influence of Different Organic Carboxylate Anions on the Crystal Structure of Silver(Ⅰ)Coordination Polymers

The reaction of AgNO3 , 4,4′-bipyridine （bpy） and 2,2′-bipyridine-3,3′-dicarboxylic acid （H2bpdc）/2,2′-biquinoline-4,4′-dicarboxylic acid （H2bqdc）/1,3-benzenedicarboxylic acid （H2bdc） gave rise to block-like crystals of [Ag4（bpy）2（bpdc）2]·13H2O（1）, [Ag2（bpy）（bqdc）（H2O）]·4.5H2O（2） and [Ag2（bpy）2（H2O）2]（bdc）·3H2O（3） by slow evaporation. All the three complexes contain sandwich-like crystal structures, in which anionic sheets built up from different anions （bpdc2- , bqdc2- and bdc2- ） and lattice water molecules via rich hydrogen-bonding interactions are inserted between the cationic silver complex layers, and the abundant Ag···Ag, Ag···N and π-π stacking interactions further strengthen the 3D frameworks. The lattice water molecules are situated among the framework of crystal structure and stabilized by rich hydrogen-bonding interactions, and lattice water molecules may play a role in the orientation of organic anions in the crystal packing. Additionally, the thermal properties of 1, 2 and 3 were also discussed in detail.

反应温度诱导的两个类三明治银配合物的异构

通过固定银离子、2,2′-联吡啶-4,4′-二羧酸(H2bina)和1,3-二(4-吡啶基)丙烷(bpp)等原料配比和反应时间,在不同反应温度下分别制备了基于Ag2簇单元的配合物{[Ag2(bpp)2][Ag2(bina)2(H2O)2].6H2O}n(1)和含Ag4簇的配合物{[Ag4(bpp)2(bina)2(H2O)2].4H2O}n(2)。结构研究与性质测试对比表明这两个类三明治型配合物不仅晶体学参数、银离子配位环境、柔性配体构象、客体水分子数目发生了变化,而且荧光及热稳定性各异。

类波纹板夹层圆柱壳的优化设计及强度可靠性分析

针对耐压圆柱壳体在满足强度要求下的轻量化问题,设计一种类波纹板夹层圆柱壳模型。针对该圆柱壳体,建立类波纹板单胞优化模型,通过响应面优化法,得到了单胞满足强度要求时质量最小的结构参数,并分析设计参数对目标函数和约束函数的影响。然后利用有限元软件Ansys Workbench校核优化后轻质夹层圆柱壳的强度,仿真结果表明:最大应力值为264.81 MPa且出现在相邻两夹层外蒙皮上,能够满足设计强度要求。最后针对强度分析中几何参数、材料属性和载荷存在的随机性,建立了应力-强度干涉模型并通过蒙特卡洛法求解,结果显示随机变量影响下的最大应力值小于340 MPa的可靠度已经超过了0.99,保证了此结构强度安全可靠性。以上分析表明,类波纹板轻质夹层结构应用于耐压壳体是可行的,该研究可为耐压壳体轻量化设计提供一定的参考依据。

金属-金属氧化物-非金属型超碱金属夹心化合物Li_3OMC_5H_5(M=Be,Mg,和Ca)的非线性光学性质研究

结合最近报道的金属-金属氧化物-非金属型超碱金属夹心化合物:Li3OMC5H5(M=Be、Mg和Ca),研究了它们的稳定结构的偶极矩(μ0)、极化率(α0)和静态第一超极化率(β0)。结果表明,μ0、α0和β0值具有明显的碱土金属原子系数依赖性和构型依赖性:μ0、α0和β0值随着碱土金属原子系数的增加(从M=Be到M=Mg再到M=Ca)和构型的翻转(从T型到H型)而明显地增加。μ0、α0和β0值的顺序分别是:0.367(M=Be,T型)<0.463(M=Mg,H型)<1.764au(M=Ca,H型);266.1(M=Be,T型)<446.5(M=Mg,H型)<474.7au(M=Ca,H型)和2263(M=Be,T型)<10678(M=Mg,H型)<14940au(M=Ca,H型)。

轻质高强类蜂窝夹层结构力学性能分析及优化

创新构形类蜂窝夹层结构相比于传统六边形蜂窝夹层结构,具有更好的力学性能。本文以类蜂窝夹层结构的面板层厚度t_(f)、夹芯层厚度c及胶粘剂层厚度t_(a)为优化参数,采用多目标遗传算法对类蜂窝夹层结构各项力学性能进行优化设计。分析了各厚度参数对夹层结构的力学性能的影响情况,同时探讨了参数协同作用下,各层厚度对力学性能的敏感程度,并根据实际工程应用情况对优化解进行折中选择。研究发现:与优化前的初始值比较,优化后的类蜂窝夹层板在x轴向等效弹性模量增长了8.17%,z轴向等效弹性模量增长了63.08%,xz面内等效剪切模量增长了19.82%,xy面内等效剪切模量减小了26.11%,弯曲刚度增长了45.31%,扭转刚度增大了69.83%,总重量减小了8.26%,较好地改善类蜂窝夹层结构的各项力学性能。该研究为夹层板结构优化设计提供了一定的参考依据,具有重要的创新意义和实用价值。

LAIR-2单克隆抗体的制备、鉴定和夹心ELISA方法的建立

为了制备LAIR 2单克隆抗体并建立夹心ELISA方法。应用淋巴细胞杂交瘤技术制备抗LAIR 2单克隆抗体 (mAb )。采用间接免疫荧光染色和流式细胞术鉴定LAIR 2的细胞分布。辣根过氧化物酶 (HRP )标记LAIR 2mAb ,并建立检测LAIR 2的夹心ELISA方法。用重导向杀伤实验 (RCA )鉴定LAIR分子参与调节杀伤功能的关系。结果成功地制备了 3株特异识别LAIR 2的mAb ,1株mAb (3G4 )能够识别LAIR 1和LAIR 2的共同表位 ,但不能在重导向杀伤实验中抑制CD16诱导的杀伤功能。夹心ELISA方法检测LAIR 2的敏感性为 5ng/ml,为LAIR

锂离子电池Si/RGO@PANI三明治纳米结构负极材料的制备与电化学性能

以石墨烯和纳米硅颗粒为起始原料,苯胺为单体,植酸为掺杂剂,过硫酸铵为氧化剂(引发剂),通过超声波的作用成功原位合成了具有三明治纳米结构的Si/RGO@PANI锂离子电池负极材料。石墨烯片层与导电聚苯胺与纳米硅颗粒构成的夹心结构可形成有效的导电网络,且具有优异的结构稳定性,能够有效缓解硅在嵌锂/脱锂过程中产生的巨大体积效应,表现出良好的循环性能和倍率性能。电化学性能测试表明,这种Si/RGO@PANI三明治纳米结构复合材料适合作为一种优良的锂离子电池负极材料。

基于钴金属有机骨架材料（ZIF-67）催化性能的牛奶中大肠杆菌O157:H7快速定量检测

建立一种基于金属有机骨架催化性能的快速定量检测牛奶中大肠杆菌O157:H7的方法。以2-甲基咪唑和CoCl2 6H2O为原料,Bola型两亲性表面活性剂为溶剂合成一种钴金属有机骨架材料(ZIF-67)。对ZIF-67的催化性能进行研究,发现ZIF-67具有和辣根过氧化物酶类似的催化活性,并能在无过氧化氢存在的情况下催化3,3’,5,5’-四甲基联苯胺显色。基于此建立一种通过磁性微球进行特异性富集,通过检测与靶标结合的ZIF-67的量间接检测牛奶中大肠杆菌O157:H7的方法,该方法的检测范围为17~1.7×108 CFU/mL,检测限为17 CFU/mL,检测过程在1 h以内。该方法能快速、简单、高灵敏度、高选择性定量地检测出牛奶中的大肠杆菌O157:H7,在食源性致病菌的快速筛查中具有重要的应用价值。

K5H11[WO2(PW9O34)2]·33H2O和K6Na2H2[Ni4(H2O)2(PW9O34)2]·23H2O的合成与表征

在常规条件下合成了2种具有一维链状结构的多金属钨酸盐K5H11[WO2(PW9O34)2].33H2O(1)和K6Na2H2[Ni4(H2O)2(PW9O34)2].23H2O(2).采用X射线单晶结构分析、元素分析和红外光谱对其进行了表征.结果表明:化合物1属于正交晶系,Fddd空间群;晶胞参数a=2.906 3 nm,b=3.179 0 nm,c=3.914 8 nm,α=90.00°,β=90.00°,γ=90.00°,V=36.194 0 nm3,Z=2,R1=0.070 6,ωR2=0.162 1.化合物2属于单斜晶系,P2(1)/n空间群;晶胞参数a=1.191 6 nm,b=1.654 7 nm,c=2.121 1 nm,α=90.00°,β=100.66°,γ=90.00°,V=4.109 8 nm3,Z=16,R1=0.063 8,ωR2=0.143 2.