银-DBSA掺杂聚苯胺的制备及应用研究

采用苯胺,过（二）硫酸铵（NH4）2S2O8、硝酸银AgNO3、甲醛、十二烷基苯磺酸钠等为原料,合成了银-DBSA掺杂的聚苯胺。最佳合成的具体条件：反应温度在0～5℃下,苯胺、（NH4）2S2O8和十二烷基本磺酸钠摩尔比为4：4：1,加入的AgNO3的物质的量为苯胺的10%,反应4.5小时后,再加适量的甲醛还原得到银-DBSA掺杂聚苯胺。样品的IR光谱表明,通过还原后峰型和峰位都发生了明显的变化。样品的XRD分析知,银-DBSA掺杂聚苯胺有很强的金属元素银的峰,样品的SEM表明,还原得到的银-DBSA掺杂聚苯胺的颗粒度更小,且有许多银白色的银粒分散在高聚物大分子中。样品的TG热分析表明,银-DBSA掺杂聚苯胺在420℃以下是很稳定的,说明掺入银后的聚苯胺的热稳定性得到了显著的增强。用四探针电阻仪测试样品的电导率约为14S/cm,因此它是很有希望用于全印制电路技术的新材料。     

软X射线多缝干涉实验研究

采用菲涅耳波带板作为色散元件，小孔压缩线宽的方法，在合肥国家同步辐射实验室在水窗波段完成了一个多缝干涉实验，观察到清晰的干涉条纹。     

Platinum zone plates for hard X-ray applications

We describe the fabrication and evaluation of platinum zone plates for 5-12 kV X-ray imaging and focusing. These nano-scale circular periodic structures are fabricated by filling an e-beam generated mold with Pt in an electroplating process. The plating recipe is described. The resulting zone plates, having outer zone widths of 100 and 50 nm, show good uniformity and high aspect ratio. Their diffraction efficiencies are 50-70% of the theoretical, as measured at the European Synchrotron Radiation Facility. Platinum shows promise to become an attractive alternative to present hard X-ray zone plate materials due to its nano-structuring properties and the potential for zone-plate operation at higher temperatures.     

Enhanced photoelectrocatalytic activity of Cr-doped TiO2 nanotubes modified with polyaniline

A facile method for preparation of Cr-doped TiO₂ nanotubes (Cr–TiO₂ NTs) modified with polyaniline (PANI) was developed. The obtained materials were analyzed with scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy. The photoelectrochemical property of PANI/Cr–TiO₂ nanotubes was studied by voltammetry, photocurrent and electrochemical impedance spectroscopy (EIS). Using PANI/Cr–TiO₂ NTs as photoanode, the removal of p-nitrophenol (PNP) by photoelectrocatalytic oxidation technique was investigated. Compared with Cr–TiO₂ NTs, PANI/Cr–TiO₂ NTs showed an increased efficiency in the photoelectrocatalytic degradation of PNP. Moreover, photoelectrocatalysis was more efficient for PNP degradation than electrochemical oxidation, direct photolysis, and photocatalysis. The influences of applied bias potential, initial concentration of PNP and solution pH on the photoelectrocatalytic degradation of PNP were investigated. Under optimized conditions, almost all PNP could be degraded on PANI/Cr–TiO₂ NTs after 2-h photoelectrocatalytic treatment.     

Stability of electrochemically prepared polyaniline films in aqueous and organic solutions

Electroactive polyaniline films have been grown by galvanostatic, potentiostatic and cyclic voltammetry techniques in organic solutions based on LiClO₄ or anilinium tetrafluoborate as salts and acetonitrile or acetonitrile/nitromethane mixtures as solvents. After storage of these films in a 1 M H₂SO₄, Na₂SO₄ aqueous solution, their stability was tested by cyclic voltammetry and impedance spectroscopy in this solution. Different levels of retention of the anodic charge have been found depending on the electrochemical technique and preparation solution. The impedance tests have revealed limited changes in the charge transfer resistance upon storage. This has been interpreted on the basis of a limited deactivation of the films, which in some cases would instead experience physical changes. Confirmation of this assumption was obtained via an SEM experiment. Films prepared by cyclic voltammetry in the above acidic solution and stored in acetonitrile-or propylene-carbonate-based electrolytes show major degradation processes, as evidenced by the appearance of quinone-like compounds and the marked increase in the charge transfer resistance. Finally, films prepared by different electrochemical techniques in acetonitrile-based solutions and stored in LiClO₄-acetonitrile reveal moderate degradation phenomena.     

硬质与超硬涂层在印制电路板微型刀具上的应用（一）——硬质HAC涂层在微钻上的应用

通过物理气相沉积方法,在PCB微钻上沉积硬质HAC涂层,采用扫描电子显微镜、纳米压痕/划痕仪、摩擦磨损试验机等仪器对涂层的硬度、结合强度等力学性能进行了研究,并进行了硬质HAC涂层微钻与未涂层微钻对比加工测试。实验结果表明,硬质HAC涂层的硬度高,与硬质合金基材结合良好,涂层的摩擦系数低;硬质HAC涂层钻头加工典型无卤素板材时,使用寿命是未涂层钻头的2.8倍。     

硬质与超硬涂层在印制电路板微型刀具上的应用（三）——超硬SHC涂层在挠性板微钻上的应用

通过物理气相沉积方法,在挠性印制电路板微钻上沉积超硬SHC涂层,对涂层的硬度、结合强度等力学性能进行了研究,并进行了超硬SHC涂层微钻与未涂层微钻对比加工测试。实验结果表明,超硬SHC涂层的硬度高,与硬质合金基材结合良好,涂层的摩擦系数低;在本实验中,超硬SHC涂层钻头加工柔性PCB板材时,使用寿命是未涂层钻头的2倍。     

十二烷基苯磺酸掺杂聚苯胺的气敏性能研究

以苯胺为单体,过硫酸铵为氧化剂,采用化学氧化聚合法分别在十二烷基苯磺酸(DBSA)和盐酸中合成了聚苯胺(PAn),并用傅里叶红外光谱和TGA-DTA技术对聚苯胺掺杂前后的结构变化和热稳定性进行了分析。研究了不同质子酸掺杂对聚苯胺气敏性能的影响。结果表明:十二烷基苯磺酸掺杂的聚苯胺,比普通盐酸掺杂的聚苯胺对目标气体具有更好的灵敏性。当r(S:N)为0.4～0.5时,在室温下其对1000×10-6NH3的灵敏度达到了10.43,响应时间为30s,恢复时间为3min。且与盐酸相比,十二烷基苯磺酸掺杂的聚苯胺具有更好的环境稳定性。     

Effects of hydrogen peroxide on the electrical conductivity of graphite/polyaniline composites

The effects of hydrogen peroxide (H₂O₂) on the direct current (dc) electrical conductivity of graphite (G)/polyaniline (PANI) composites are studied. It was found that the conductivity of G/PANI composite reacted with H₂O₂ decreases with increasing time. Results are confirmed by UV–vis, FTIR absorption measurements, X-ray diffraction analysis and Raman spectroscopy. From X-ray diffraction and Raman spectroscopy measurements we prove that H₂O₂ affects only PANI but not Graphite particles. After their treatment with H₂O₂ only G(10%)/PANI, G(20%)/PANI and G(30%)/PANI samples show a semi-conductor behavior. The charge transport mechanisms in these three samples are due to hopping and tunneling and are described by both Mott's three-dimensional variable range hopping model and Sheng's fluctuation induced tunneling model. The transition in the nature of charge transport in G(10%)/PANI, G(20%)/PANI and G(30%)/PANI samples after treatment with H₂O₂ is caused by disorder and localization, whereas the inverse semi-conductor-metal transition which occurs at above G(30%) in the same samples arises essentially from percolation in G/PANI composites.     

聚苯胺光学吸收及应用

从结构和性能的角度对聚苯胺不同形态因电子或极子跃迁引起的在可见近红外区的吸收特性进行了总结。重点讨论了本征态盐的分子链构像结构对光学吸收的影响，报道了作者在降苯胺用于透明导电材料和节能方面的一些设想和研究结果。     

Electrochemical synthesis of electroactive polyaniline in organic solutions

Polyaniline films have been grown in solutions based on acetonitrile or acetonitrile/nitromethane mixtures by galvanostatic, potentiostatic and cyclic voltammetry techniques. LiClO₄ or anilinium tetrafluoborate was used as a salt. With the latter, aniline was absent in some tests, since anilinium could act simultaneously as a charge carrier and a polymerising species. The film characteristics have been evaluated by cyclic voltammetry, impedance spectroscopy and SEM experiments. It has been found that the protons released by aniline (following oxidation) or anilinium can be made available to the g| wing chains if the protophilic character of the solvent is sufficiently low. In a 1/1 acetonitrile/nitromethane mixture the galvanostatic and potentiostatic techniques produce electroactive films of reduced resistance, especially if anilinium tetrafluoborate is present. These seem to be the best conditions for the synthesis.     

A new class of portable X-ray apparatuses based on carbon nanocluster cathodes

Principles of the development of high-power pulsed X-ray sources based on explosive emission from carbon nanoclusters are stated. Designs and main parameters of the developed X-ray tubes ( the electron flow exciting the X-ray radiation is 100?500 А, the voltage is 20?150 kV, the pulse length is 10?20 ns, and the nanosecond pulse repetition rate is 1?10³ Hz) are reported.     

Enhancement of electrical characteristics of electrospun polyaniline nanofibers by embedding the nanofibers with Ga-doped ZnO nanoparticles

Polyaniline nanofibers embedded with undoped ZnO nanoparticles (NPs) or Ga-doped ZnO (ZnO:Ga) NPs were fabricated and their structural and electrical properties were investigated. The uniform distribution of the NPs inside the polyaniline nanofibers was confirmed by transmission electron microscopy analysis. Polyaniline nanofibers embedded with ZnO:Ga-NPs showed their higher conductivities, compared with polyaniline nanofibers embedded with undoped ZnO-NPs. Single nanofibers electrospun from a mixture of a polyaniline solution with a 30 vol% ZnO:Ga-NPs dispersed-solution showed approximately five times higher conductivity than those electrospun from the polyaniline solution alone. This observation indicates that the embedding of the ZnO:Ga-NPs significantly enhances the electrical characteristics of the polyaniline nanofibers.     

Microwave absorption and permittivity of polyaniline thin films using overlay technique

This paper reports the use of nonresonating microstripline for investigation of polyaniline thin film using overlay technique. Microwave absorption, DC conductivity, microwave conductivity, shielding effectiveness and microwave permittivity and dielectric loss of the conducting PANI films are reported. DC conductivity was between 0.15×10⁻³ and 3.13×10⁻³ S/cm. Microwave conductivity was between 0.1 and 10 S/cm. The PANI films coated on alumina gave shielding effectiveness values of −1 to −8 db. The ε′ was between 40 and 350. Measurements have been carried out over the frequency range 8.2-18 GHz. The effect of thickness of the overlay is also reported.     

Fabrication and characterization of urchin-like polyaniline microspheres using lignosulfonate as template

An urchin-like conducting microsphere was fabricated by synthesizing polyaniline, PANI, with lignosulfonate, LGS. FESEM images showed that this special PANI structure was controllably formed because the pure PANI presented only a nanofiber formed mat, and the PANI/LGS mixture with the ANI/LGS ratio (%) at 36/1 and 18/1 formed spheres while the PANI nanofibers lied on spherical surface, and only at 9/1 led the PANI nanofiber to stand on sphere surface in the urchin-like structure. Taking the pure PANI as a reference, the urchin-like PANI/LGS microsphere has been found to have enhanced conductivity and thermal stability.     

X光影像仪光采集系统的研制

X光影像仪的光采集系统是X光影像仪的核心。本文介绍了X光影像仪的光采集系统的原理以及在提高光采集系统的荧光收集率和采集信号的信噪比和提高图像处理质量方面的努力。     

Study on the thermal properties of doped PMMA systems

The thermal optical coefficient (TOC) and volume thermal expansion coefficient (TEC or β) of poly(methyl methacrylate) (PMMA) polymers doped with azobenzene dyes were investigated. A novel approach for determining the TEC has been suggested and a non‐linear variation in the TOC with increasing wt% of the dopant has been observed and tentatively explained. In addition, the refractive index (RI) contrast necessary for forming a waveguide was demonstrated to be easily achievable by adding a higher‐refractive‐index material to the blank polymer. Copyright © 2000 John Wiley & Sons, Ltd.     

用TOGA／COARE试验中机载雷达资料进行衰减效应订正的个案研究

为了蛎限度地利是生载测雨雷达，必须实现一些主要条件：高的空间分辨率、宽阔的覆盖面积，大的动态降雨测量范围以及精确的点测量。     

应用微分电磁理论研究软X光衍射光栅

微分法是软Ｘ光波段唯一精确计算衍射光栅效率的电磁理论。应用这种理论成功地设计出带有位相光栅的软互光激光反射输出镜，计算出可能的实验误差。对微分理论的数值结果和精度进行了分析和讨论。     

The effect on the impedance characteristics of the metal oxides (Al2o3 and Zno) doping into polyaniline

In this study, the doping metal oxides; ZnO and Al₂O_3, (MO for short) into poly (aniline) (PANI) how that affects the dielectric properties have been investigated by the impedance analysis technique. PANI, PANI-Al₂O₃ and PANI-ZnO were synthesized by chemical oxidative polymerization. Both FTIR and SEM are used to characterize the structure and morphologies of these composites. Dielectric properties of PANI and PANI–MO composites have been performed in the frequency range 100 Hz −1 MHz. It was seen that the values of the dielectric constant and impedance increase with doping Al₂O₃ and ZnO into PANI. Absorption coefficient (α) and relaxation times (τ) parameters were calculated and it is revealed that the relaxation mechanism changed significantly by the doping of metal oxide into PANI. Moreover, the conductivity properties of PANI-MO composites were performed and it is seen that “s” parameter value correlated Barrier Hoping (CBH) Mechanism.