磁场退火对CoFe2O4微粒形貌及磁性能的影响

采用化学共沉淀法合成材料,分别在0.1T和0.5T的磁场下800℃退火制备了CoFe2O4颗粒样品,系统研究了磁场退火对样品形貌和磁性能的影响.X射线衍射(XRD)谱和扫描电子显微镜(SEM)分析结果表明,磁场退火后样品结晶度变好,因磁场诱导而生成较圆润的圆形颗粒.磁测量结果表明,磁场下退火制备的样品反位缺陷减少,从而...     

层层自组装石墨烯/聚苯胺纳米复合电极

采用循环伏安法电化学沉积聚苯胺和电化学还原氧化石墨烯,得到层层自组装石墨烯/聚苯胺复合材料.通过扫描电子显微镜、透射电镜对物相结构进行了表征,通过测试不同组装层数下石墨烯/聚苯胺纳米复合电极材料的比电容优化制备工艺,并利用电化学工作站测试其电化学性能.结果表明:制备的聚苯胺/石墨烯复合材料具有优异的赝电容性能,当电流密...     

脉冲电容器在磁力成形及组装工艺中的应用

介绍了以脉冲电容器为储能器件的脉冲磁场成形和组装系统及成形组装工艺的原理和基本组成。对脉冲电容器在该工艺中的一些状态参数进行了讨论 ,简单介绍了脉冲磁场成形和组装系统在工业部门中的典型应用     

有场制备磁流变弹性体的磁路分析

磁流变弹性体是由铁磁颗粒混合于弹性基体制备而成的一种新型智能材料,其弹性刚度可由外加磁场加以控制。其制备方式可分为两种,即有场制备和无场制备,且有场制备的材料性能优于无场制备。研究并设计了不同的加磁装置用以制备磁流变弹性体,用线圈加磁装置方便磁场调节;而使用永磁体加磁时,有导磁回路的磁场明显大于直接用永磁体进行加磁,并且作用于磁流变弹性体的磁场更加均匀,磁力线几乎无发散,磁场利用率高。最后使用有导磁回路的永磁体加磁结构制备了磁流变弹性体材料。     

新型场效应管型湿度传感器阵列的研制

以Baytron P为敏感材料,利用自组装技术在具有4个单元的无金属栅场效应管阵列上制备了Baytron P/PDDA多层自组装超薄膜,形成了一种以自组装膜取代MOSFET栅金属的化学场效应管型湿度传感器阵列,并对该阵列的湿敏特性进行了测试研究,同时设计了广义回归神经网络以进行湿度的预测分析.结果表明,采用1V漏电压下的漏电流值作为网络的输入,并取扩展常数为0.14时,网络的预测结果最好(最小相对误差为1.77%).     

无碳膜磁头表面氟代硅烷自组装膜制备和摩擦学性能

利用分子自组装技术,在磁头表面制备1H,1H,2H,2H-全氟癸烷基三氯硅烷(FDTS)自组装膜并进行表征和摩擦学性能研究。实验结果表明:当反应时间为8 min时,无碳膜磁头表面可制备膜厚1.2 nm、接触角值111.5°、表面粗糙度0.198 nm的FDTS单层自组装膜;当反应时间超过50 min后,无碳膜磁头表面可制备不完整的FDTS双层自组装膜。FDTS自组装膜能够极大地降低无碳膜磁头起停过程的粘着力,增强磁头的摩擦磨损性能。     

磁性胶体晶体的制备与呈色特性

通过化学合成的方法制备出被表面活性剂聚丙烯酸(PAA)修饰的Fe3O4纳米粒子,并应用透射电子显微镜、X射线衍射、磁强计及傅里叶红外光谱仪对产物进行表征,同时利用FDTD solutions光学软件对产物的呈现性能进行建模仿真。最后通过分析得到制备的胶体产物具有超顺磁性能,粒径均一,在水中具有良好的分散性,粒子分散在水中形成的胶体在外在磁场的作用下能够自组装成液态光子晶体,不同磁场大小的调节下能够呈现不同的结构色,磁场越小,颜色越向着波长大的方向偏移,同时,用软件对胶体粒子仿真得到的呈色特性与实验结果一致。这种光子晶体在结构色印刷、传感器、防伪等各个领域有广泛的应用     

有机硫化物自组装膜在锂电池中的应用可行性

从有机硫化物自组装膜的结构与电化学性质出发,分析了有机硫化物自组装膜在锂电池中应用的可行性.从有机硫化物自组装膜锂电池的制备方法、电化学性质与锂离子的传输机理几个方面综述了有机硫化物自组装膜锂电池的研究进展,并指出了制约有机硫化物自组装膜锂电池的发展瓶颈与今后研究的热点.     

脉冲电容器在磁力成形及组装工艺中的应用

介绍了以脉冲电容器为储能器件的脉冲磁场成形和级装系统及成形组装工艺的原理和基本组成。对脉冲电容器在该工艺中的一些状态参数进行了讨论，简单介绍了脉冲磁场成形和组装系统在工业部门中的典型应用。     

Ba-M型六角铁氧体的性能及自偏置环行器仿真设计

采用传统固相反应法结合磁场成型技术制备高取向的Ba-M型六角铁氧体。结合材料性能利用Ansoft HFSS仿真软件建立自偏置环行器三维电磁场模型,设计Ka波段自偏置环行器。实验结果表明,磁场成型铁氧体材料的取向度为0.7,剩磁比为0.88,各向异性场为18.3 kOe;高的各向异性场有望使材料在毫米波高频器件中得到应用。在56.4 GHz材料铁磁共振线宽为377 Oe,理论分析结果显示,铁磁共振线宽主要来源于气孔致宽。仿真结果表明,在32.9~35.8 GHz频率范围内,自偏置环行器的插入损耗小于0.89 dB,并表现出良好的环行性能。     

Fluidic self-assembly of micromirrors onto microactuators usingcapillary forces

The authors discuss the application of self-assembly techniques for positioning microscopic components onto a substrate in a desired configuration. The basis is a fluidic self-assembly technique in which capillary forces assemble microparts with submicrometer alignment precision. A heat-curable acrylate-based adhesive is used to provide the capillary forces for assembly and is then polymerized in a bath of water at 80°C for 16 h with continuous nitrogen bubbling. The application we describe is self-assembly of flat silicon micromirrors; onto surface-micromachined actuators for use in an adaptive-optics mirror array. Photolithography defines shapes of hydrophobic self-assembled monolayers for self-assembly. Mirrors with fill factors up to 95% were assembled. Mirrors 464 μm in diameter and assembled onto actuators remain flat to within 6 nm rms. This mirror quality would be difficult to attain without the process decoupling afforded by microassembly. The general self-assembly approach described here can be applied to parts ranging in size from the nanometer to the millimeter scale and to a variety of part and substrate materials     

Nanotechnology and biomimetics with 2-D protein crystals

The application potential of crystalline bacterial cell surface layers (S-layers) as nature-tailored supramolecular structures is described. The fabrication of supramolecular devices requires molecules that are capable of interlocking in a well-defined manner. Thus, molecular self-assembly systems that exploit the molecular-scale manufacturing precision of biological systems are prime candidates for supramolecular engineering. Although self-assembly of molecules is an ubiquitous strategy of morphogenesis in nature, researchers in the area of molecular nanotechnology and biomimetics are only beginning to exploit its potential for the functionalization of surfaces and interfaces as well as for the production of biomimetic membranes and encapsulation systems. This article presents an overview of a new approach in nanostructure technology and biomimetics based on crystalline bacterial cell surface layers.     

不同介孔结构的磷酸钛的制备及性能

采用溶胶凝胶模板法结合煅烧的方法,通过选用不同的模板剂合成得到具有不同介孔结构的磷酸钛材料,运用X-射线粉末晶体衍射技术(XRD)、低温N_2吸脱附技术和高分辨透射电子显微技术(HRTEM)对样品进行了表征,并分别对各材料的介孔结构及其电化学性能进行了研究.结果表明.材料介孔结构的长程有序性及其孔径大小都对材料的电化学性能有影响,例如在大电流密度下(如:150 mA/g),长程有序性较好的与长程有序性较差的磷酸钛介孔材料的首次放电比容量分别为93.9、67.9 mA/g,经过100次循环后,容量的保持率分别为54%、20%;大孔径与小孔径的磷酸钛介孔材料的首次放电比容量分别为96.1、67.9 mA/g,经过50次循环后,容量的保持率分别为66%、17%.     

The preparation and characterization of porous carbons for hydrogen storage

Porous carbon materials with a cylindrical pore structure were prepared using ordered mesoporous silica as a removable template. To investigate the effect of the structural and textural properties of the products on hydrogen adsorption capacity, different carbon precursors and synthetic methods were used in their preparation. All of the carbon materials prepared showed a well-defined pore structure with a high surface area irrespective of the carbon precursor used in the preparation. Hydrogen adsorption tests indicated that the capacity of the materials for hydrogen adsorption was highly dependent on total surface area and the pore structure. Based on the N₂ sorption results, the total surface area was directly correlated with the hydrogen adsorption capacity.     

Dielectric relaxation in piezo-, pyro- and ferroelectric polyamide 11

Ferroelectric polyamide 11 films were prepared by melt-quenching, cold-drawing and electrical poling. Their ferroelectricity was studied by means of dielectric-hysteresis measurements. A remnant polarisation of up to 35 mC/m/sup 2/ and a coercive field of 75 MV/m were obtained. The piezoelectric d/sub 33/ coefficient and the pyroelectric coefficient of the films are reduced by annealing just below the melting region, but remain at about 3 pC/N and 8 /spl mu/C/(m/sup 2/K), respectively, during further heat treatment. Differential scanning calorimetry (DSC), dielectric relaxation spectroscopy (DRS) and thermally stimulated depolarisation (TSD) were applied for investigating the conformational changes induced by melt-quenching, cold-drawing and annealing. The results indicate that the cold-drawn film mainly consists of a rigid amorphous phase which exhibits considerably lower conductivity, no glass transition and consequently no dielectric /spl alpha/ relaxation. Instead, an /spl alpha//sub r/ relaxation is found, which is related to chain motions in regions of the rigid amorphous phase where the amide-group dipoles are not perfectly ordered. Annealing removes imperfectly ordered structures, but does not affect the ferroelectric polarisation. Therefore, it may be concluded that essentially the /spl alpha//sub r/ relaxation causes the thermally nonstable part of the piezo- and pyroelectricity in polyamide 11.     

基于诱导有序加权平均算子的最优组合短期负荷预测

为提高预测精度,弥补现有组合预测方法中单项预测方法在各预测点的加权系数恒定等不足,提出了一种新的组合预测方法——基于诱导有序加权平均算子（induced ordered weighted averaging operator,IOWA）的短期负荷最优组合预测方法。该方法针对同一预测方法在不同时刻的预测效果不同,按照各单...     

Mg2+不同取代位对LiFePO4/C性能的影响

以蔗糖为碳源,用高温固相法制备了Li0.98Mg0.02FePO4/C、LiFe0.98Mg,0.02PO4,/C和不确定掺杂位的样品LiFePO/C+Mg2+的正极材料.用XRD,SEM、恒流充放电测试、循环伏安和交流阻抗谱方法,研究了样品的结构、形貌及电化学性能.研究发现,样品均为单一规则的橄榄石型的LiFeP0,...     

Electrochromic property of the viologen-anchored mesoporous TiO2 films

The electrochromic properties of the viologen-anchored mesoporous TiO₂ (Meso-TiO₂) films were investigated in this work. The Meso-TiO₂ films, synthesized by evaporation-induced self-assembly (EISA) process, deposited on ITO electrodes were a worm-like structure with an average pore diameter of 7.0 nm. The electrochromic devices (ECDs) fabricated from the Meso-TiO₂ demonstrated 3 times of coloration efficiency and considerably faster switching response, compared with those from the nanocrystalline films made of the 7 nm-sized TiO₂ nanoparticles. The advantage of the Meso-TiO₂ would originate from the well-organized mesopore structures, offering an efficient electrolyte transport as well as the fast electron transfer from the ITO electrode to the anchored viologen.     

特高压GIS现场安装用全封闭移动式厂房导轨基础设计与施工

1 000 kV气体绝缘金属封闭开关（gas insulated metal-enclosed switchgear,GIS）设备的安装是特 高压交流变电站工程施工过程中的关键工序。为保证1 000 kV GIS设备的安装条件,同时为施工人员提供舒适 的工作环境,国网交流公司积极组织研制了特高压GIS现场安装用全封闭移动式厂房,并在浙北—福州特高压交 流输变电工程中的3个新建变电站工程中全线推广。对移动厂房的总体情况进行了介绍,重点研究了移动厂房的 导轨基础设计,结合移动厂房在浙北—福州工程现场的实际应用情况,从厂房导轨基础形式的选择、设置位置 确定以及导轨基础对原有设备基础施工的影响等方面进行了介绍和分析。     

嵌段共聚物对树脂基多孔炭电化学性能的影响

以间苯二酚(R)、甲醛(F)为原料,盐酸作催化剂,通过添加嵌段共聚物F127作致孔剂,利用溶液协同自组装和炭化处理制备多孔炭材料。采用扫描电镜、透射电镜和N2吸附分析不同F127加入量制得的多孔炭材料的形貌和孔隙结构,并利用直流充放电、交流阻抗技术和循环伏安法测定以上述多孔炭材料为电极的双电层电容器(EDLC)的电化学性能。结果表明:酸催化下的酚醛树脂基体网络结构在炭化过程中较好地保留了F127形成的微相结构,不同F127加入量制得的多孔炭材料比表面积在640～700 m2/g。F127/R为1.3时制得的多孔炭材料比表面积为701.2 m2/g,孔容为0.54cm3/g,其中中孔孔容0.362 cm3/g,中孔率达67.04%;在30%KOH电解质溶液中低电流密度(1 mA/cm2)充放电时的比电容为165 F/g,电流密度增大20倍,容量保持率为95%,经过5 000次循环,容量保持率达94%以上,具有良好的大电流充放电性能和循环性能。