纳微结构Cu/氧化石墨烯的制备及摩擦学性能研究

以Cu SO4与氧化石墨烯为原料利用原位还原技术制得纳微米结构铜/氧化石墨烯复合微粒。利用透射电镜(TEM)、场发射扫描电镜(FESEM)和X射线衍射(XRD)对Cu/氧化石墨烯复合微粒进行表征。将复合微粒修饰并添加到液体石蜡中,利用四球摩擦磨损试验机考察其摩擦学性能。结果表明,利用原位还原技术制备的纳微米结构的Cu/氧化石墨烯复合微粒中铜的粒径在100 nm之内;在392 N、1 450 r/min、30 min实验条件下,质量分数2.0%的复合微粒可使液体石蜡的摩擦因数下降33%,质量分数0.5%的复合微粒可使钢球磨斑直径下降25%。     

基于还原氧化石墨烯修饰电极和智能手机的小型电化学分析仪

目的:设计一款基于智能手机的小型电化学分析仪,以实现对不同浓度的葡萄糖溶液的定量检测.方法:通过还原氧化石墨烯对工作电极表面进行功能化,制备了高灵敏度的葡萄糖传感器.采用LMP91000传感芯片设计而成的恒电位仪模块为传感器提供特定的激励信号并将测得的实验结果无线传输到智能手机上.采用智能手机进行数据处理和浓度计算,并...     

少层氧化石墨烯材料的理化性能表征分析

氧化石墨烯材料具有优异的物理化学性质,在能源、环境、生物医药和传感器等众多领域具有广泛应用。氧化石墨烯材料表面具有丰富的电负性官能团,能够与活性组分通过化学耦合作用进行负载和分散,可有效提高复合材料的性能,被认为是理想的载体材料。国家标准定义少层石墨烯材料是3到10个完整的石墨烯层堆垛构成的二维材料。目前很少有文献系统报道少层氧化石墨烯材料的关键理化性能参数的表征分析。本研究基于超声辅助Hummers法制备了高质量少层氧化石墨烯材料,并依据先进表征技术测量分析了少层氧化石墨烯的物相组成、微观结构、厚度/层数、表面官能团、结构缺陷等关键理化性能参数,为氧化石墨烯材料的检测分析及下游粉体复合材料的应用研究提供了重要参考。     

蓖麻油基含氧化石墨烯润滑脂的制备及其性能研究

以蓖麻油为基础油,以一水氢氧化锂、12-羟基硬脂酸和癸二酸为稠化剂原料,氧化石墨烯(GO)为添加剂,制备3种含GO不同质量分数的混合锂基脂,分别利用锥入度试验器、钢网分油测试仪、滴点试验器、流变仪、热重分析仪、摩擦试验机和三维形貌仪考察其理化性能和润滑性能,探讨GO对蓖麻油基润滑脂的作用机制。结果表明:含GO混合锂基脂的黏度随剪切率和温度的增加均呈非线性减小的变化趋势,但随着剪切速率和温度的升高,GO对蓖麻油基润滑脂的黏度与剪切速率关系和黏温特性影响越来越小;微量的GO能够提高混合脂的热稳定性能;混合锂基脂的平均摩擦因数随GO质量分数的增加呈先减小后增大的变化趋势,适量的GO有助于提高蓖麻油基润滑脂的减摩抗磨性能,这是因为摩擦过程中GO以片层形式进入摩擦副的接触区,能够有效地降低摩擦副表面的直接接触概率,且GO具有自润滑性能,在摩擦副界面上发挥较为有效的润滑作用。     

静电自组装制备氧化石墨烯包覆铜粉研究

为了改善石墨烯与铜之间浸润性差及石墨烯自身难以分散的问题,制备高分散石墨烯增强铜基复合材料,利用静电自组装法制备了氧化石墨烯包覆铜粉,用不同修饰剂(十六烷基三甲基溴化铵(CTAB)、1-丁基-3-甲基咪唑四氟硼酸盐离子液体([BMIm]BF₄)、1-丁基-3-甲基咪唑六氟磷酸盐离子液体([BMIm]PF₆))改性铜粉表面后,研究了氧化石墨烯对其包覆效果的影响;进而研究了不同含量[BMIm]BF₄离子液体改性后氧化石墨烯包覆效果及复合粉末热稳定性。结果表明,3种修饰剂对铜粉表面改性后,氧化石墨烯成功包覆到铜粉表面,[BMIm]BF₄离子液体修饰后包覆效果最佳,CTAB次之,[BMIm]PF₆离子液体最差,当[BMIm]BF₄离子液体与铜粉比例为1.5 mL:60 g时,氧化石墨烯均匀包覆在铜粉表面,氧化石墨烯包覆铜粉在高温下可被还原为石墨烯。     

油溶性氧化石墨烯的制备及在润滑油中的摩擦学性能

以长链脂肪族十八烷基胺(ODA)为改性剂,对氧化石墨烯(GO)进行表面化学修饰得到改性氧化石墨烯(GO-ODA)。考察GO-ODA作为CD/10W-40润滑油添加剂的分散稳定性,采用红外光谱、X射线衍射谱、扫描电镜和X射线光电子能谱等手段对GO-ODA的结构和形貌进行表征,采用四球摩擦试验机对GO-ODA在CD/10W-40润滑油中的摩擦学性能进行测试。结果表明:通过酰胺化反应可以在GO表面成功接枝ODA,改性后GO在润滑油中分散稳定性显著提高,静止30天没有任何沉淀。摩擦磨损测试发现,质量分数为0.01%的GO-ODA,可使CD/10W-40润滑油的摩擦因数下降16%左右,磨斑直径减小10%;GO-ODA的磨损机制主要表现为塑性变形、黏着磨损和磨粒磨损。     

氧化石墨烯/碳纳米管复合薄膜制备及表征

将氧化石墨烯(GO)和COOH官能基多壁碳纳米管MWCNT-COOH在去离子水中混合。用超声探针对GO/MWCNT-COOH水溶液进行超音波处理。表面活性剂Triton X-100能使GO和MWCNT-COOH在水中更好地分散。使用真空泵,使悬浮液通过PTFE膜过滤,GO和MWCNT-COOH混合水溶液沉积在PTFE过滤膜上形成复合薄膜。用扫描电子显微镜对薄膜进行表征。用纳米压痕仪检测薄膜的力学性能,通过霍尔效应检测薄膜的导电性能。结果表明,复合薄膜随着GO含量的增加杨氏模量和硬度不断提高,还原前复合薄膜随着GO含量的增加导电率不断降低,热处理还原后复合薄膜随着GO含量的增加导电率迅速增大。     

石墨烯半浮栅场效应晶体管的制备与电学特性研究

基于石墨烯材料的半浮栅场效应晶体管因其非易失性的存储特性而被广泛研究。通过定点转移工艺制备了一种以少层石墨烯为沟道,六方氮化硼作为隧穿势垒层,石墨烯作为半浮栅电荷俘获层的石墨烯场效应晶体管。由于其独特的半浮栅结构,器件的转移特性曲线出现双狄拉克点。对器件转移特性曲线双狄拉克点现象进行了系统理论分析。另外,得到石墨烯浮栅器件的稳定保留特性,在200 s内,器件存储擦除电流差可以维持在20μA左右。所提出的研究有助于实现基于半浮栅结构的二维材料多功能光电子器件。     

功能化氧化石墨烯-酞菁复合物的润滑特性*

以无金属酞菁复配胺边缘功能化氧化石墨烯制备一种环境友好型润滑油添加剂,采用SEM、FTIR、Raman、TGA验证其结构。采用UV-Vis考察其在偏苯三酸酯TM320基础油中的分散性,发现胺边缘功能化氧化石墨烯-酞菁复合物分散稳定性好。利用四球摩擦磨损试验机MS-10A评价其在偏苯三酸酯TM320基础油中的润滑特性,结果发现其具有优异的减摩抗磨性能,摩擦因数和磨斑直径分别较纯基础油下降了25.3%和24.1%。通过XANES和SEM-EDS分析发现,摩擦表面的摩擦膜由功能化氧化石墨烯-酞菁复合物组成,表明可能是酞菁的强配位空穴和胺边缘功能化氧化石墨烯的强吸附协同增效,使其在摩擦过程中能在摩擦副表面快速形成有效的界面润滑膜。     

高循环稳定性碳化钛/氧化石墨烯复合超级电容

二维材料碳化钛(Ti₃C₂T_x)因具有高导电性和大比表面积的特点,在作为超级电容电极材料时,可以实现较高的能量密度。然而,Ti₃C₂T_x在储能过程中会出现不可逆的氧化失活反应,而且它与基底间的结合力较差,这将导致碳化钛超级电容的循环稳定性欠佳,极大地阻碍了其作为电极材料的广泛应用。将Ti₃C₂T_x作为活性层与氧化石墨烯(GO)分层复合制作成超级电容电极,覆盖在Ti₃C₂T_x薄膜之上的GO层可以削弱氧化失活反应。同时,对电极的热处理可提升Ti₃C₂T_x对基底的附着力。这使得Ti₃C₂T_x/GO复合电极的充放电循环稳定性明显改善,在5 000次循环之后其容量仍高于初始容量。该设计可为制备高循环稳定性超...     

Potential of a sensitive uric acid biosensor fabricated using hydroxyapatite nanowire/reduced graphene oxide/gold nanoparticle

In this study, a ternary nanocomposite consisting of gold nanoparticles (AuNPs), hydroxyapatite (HAP) nanowires, and reduced graphene oxide (rGO) is synthesized by a simple one‐step hydrothermal method, which is used to modify glassy carbon electrode (GCE) for detecting uric acid. The nanocomposite is characterized through various methods such as scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction. Electrochemical measurements of the modified GCE are performed in a conventional three‐electrode system. Experimental results show that the obtained HAP nanowire and rGO are mixed homogeneously, and the AuNPs are deposited into this matrix. The GCE modified by the nanocomposites have superior electrocatalytic activities for uric acid. The peak current intensities of UAO (uricase)/HAP‐rGO/AuNPs sensing system linearly increase as the uric acid concentration increases substantially in a range of 1.95 × 10^?5 to 6.0 × 10^?3 M (R² = .9943), with a detection limit of 3.9 × 10^?6 M (S/N = 3) and analytical sensitivity of 13.86 mA/M. The biosensor performs well in determining uric acid concentration in human urine samples.     

石墨烯热电器件栅控特性研究

为了获得一种稳定可控的能源,提出一种栅控石墨烯热电器件。通过对石墨烯通道的载流子输运机理的分析,获得了温度和栅压对通道电阻的影响。依据半经典Mott公式推导了石墨烯塞贝克系数的表达式,同时给出了石墨烯的电导率和热导率模型。最后通过有限元分析(FEA)建模获得不同栅压条件下的器件温度,当栅极电压V_B=0 V时,石墨烯热电器件热端和冷端温度差为30 K;当V_B=6 V时,最大温差达到50 K;当V_B=30 V时,最小温差只有10 K。结果表明,栅压对热电器件的性能有明显的调控性。该研究可为石墨烯热电器件的设计提供理论参考。     

Tribological properties of few-layer graphene oxide sheets as oil-based lubricant additives

The performance of a lubricant largely depends on the additives it involves. However, currently used additives cause severe pollution if they are burned and exhausted. Therefore, it is necessary to develop a new generation of green additives. Graphene oxide (GO) consists of only C, H and O and thus is considered to be environmentally friendly. So the tribological properties of the few-layer GO sheet as an additive in hydrocarbon base oil are investigated systematically. It is found that, with the addition of GO sheets, both the coefficient of friction (COF) and wear are decreased and the working temperature range of the lubricant is expanded in the positive direction. Moreover, GO sheets has better performance under higher sliding speed and the optimized concentration of GO sheets is determined to be 0.5wt%. After rubbing, GO is detected on the wear scars through Raman spectroscopy. And it is believed that, during the rubbing, GO sheets adhere to the sliding surfaces, behaving like protective films and preventing the sliding surfaces from contacting with each other directly. This paper proves that the GO sheet is an effective lubricant additive, illuminates the lubrication mechanism, and provides some critical parameters for the practical application of GO sheets in lubrication.     

基于石墨烯太赫兹调制器的研究

利用石墨烯的电导率可以通过电压调节的特性,研究了一种基于单层石墨烯的太赫兹调制器。为了提高太赫兹-石墨烯相互作用强度,调制器采用一种石墨烯-金属复合结构。全波电磁数值仿真结果表明,在反射工作模式下,该器件在3.5 THz的调制深度大于90%。采用平面半导体工艺,实现了调制器原型器件,并对其反射谱进行了测试,实验数据与仿真结果相符,这为以后实现高质量的太赫兹调制器奠定了基础。     

Synthesis and tribological behaviour of oleic acid‐capped lanthanum borate/graphene oxide nanocomposites

The lanthanum borate/graphene oxide (LB/GO) nanocomposites were obtained by GO decorated by LB using an eco‐friendly hydrothermal method. For improving the oil solubility of the LB/GO nanocomposites, the oleic acid (OA)‐capped LB/GO (OA–LB/GO) nanocomposites were achieved. The as‐prepared nanocomposites were determined by a series of characterisations such as Fourier transform‐infrared spectroscopy (FT‐IR), X‐ray powder diffraction (XRD), Raman, UV‐vis, transmission electron microscopy (TEM) and SEM. The results indicated that most of LB nanoparticles with the size of 50–100 nm were well loaded on the surface of GO nanosheets. In addition, the tribological properties of the as‐prepared nanocomposites were tested by a four‐ball friction machine. The results demonstrated that the OA–LB/GO nanocomposites were of good anti‐wear ability and excellent load‐carrying capacity. Copyright © 2016 John Wiley & Sons, Ltd.     

Strong hydrophobic interaction between graphene oxide and supported lipid bilayers revealed by AFM

Understanding the interaction between graphene oxide (GO) and lipid membranes is of great importance for its various applications in biotechnology. Here, we investigated the interaction between GO and charged supported lipid bilayers (SLBs) by in situ atomic force microscope (AFM) imaging. It was found that GO could peel off a single layer of positively charged SLBs and deposited on the hydrophobic part of the remaining sublayer. Then free lipid molecules would assemble on GO surface and formed 1.5 bilayers in a lipid‐GO‐lipid manner. For negatively charged lipid bilayers, however, GO deposited to the SLBs only when its concentration was very high. These results indicate that, in addition to electrostatic interaction, the hydrophobic interaction plays an important role when GO sheets deposit onto the charged lipid bilayers, and should be helpful to understand possible cytotoxicity and antibiosis of graphene‐related nanomaterials. Microsc. Res. Tech. 79:721–726, 2016. © 2016 Wiley Periodicals, Inc.     

基于CCD器件信号调理电路的研究

采用电荷藕合器件（CCD）设计了有限脉冲响应系统，该系统可以作为补偿网络补偿仪器、传感器之类的各种测量器件或系统的频率响应特性，以拓展其工作频带。本设计的主要优点是其柔性，只要对CCD的加权电阻以及CCD所能工作的时钟频率加以变化，即可很容易地适应于补偿任意给定的未补偿的非零响应。最后，在计算机模拟仿真的条件下，证实了设计原理的正确性，并给出了一些结论。     

基于TRIZ理论的可控自动浇花装置的研究

介绍TR IZ理论的理论基础,其中分析冲突解决原理和冲突矩阵、物质场分析理论以及发明问题解决算法（AR IZ）等。运用TR IZ理论对自动浇花装置进行了具体研究和创新设计,提出可控自动浇花装置的总体设计方案。本实用新型解决了浇花装置自动化和浇花过程中的水流量控制问题等。