355 nm激光光电离甲醛飞行时间质谱的研究

利用脉宽为5 ns脉冲Nd: YAG 355 nm激光在功率密度为10¹¹–10¹² W/cm²条件下实现了甲醛含水团簇多光子电离, 并用飞行时间质谱对其电离产物和电离过程进行了研究. 实验中观测到了甲醛的质子化团簇系列 (CH₂O)_nH⁺(n=1–4), 甲醛的去质子化团簇系列(CH₂O)_nCHO⁺ (n=1–3), 以及两个起源于H₂CO去质子和质子化的含水团簇系列HCO⁺(H₂O)_n(n=1,3,5)和H₃CO⁺(H₂O)_n(n=1,3,5), 并对其中的一些团簇结构构型进行了猜测. 研究在不同的激光功率密度下甲醛团簇质谱峰的变换情况, 当激光密度达到9.3× 10¹¹ W/cm², 开始出现CH₂O和H₂O本体及其光致碎片的信号, 但对应的各质量峰没有明显地分辨开, 而是以包络的形式出现, 这是激光电离产生高能离子释放的一种表现, 提出认等离子体动力学鞘层加速机制(模型)来解释高能离子形成的物理机制. 关键词： 甲醛 团簇 飞行时间质谱 激光电离     

PPy/Nafion(R)复合膜的制备及性能表征

用0.5mol·L-1的FeCl3溶液作引发剂,采用原位化学聚合法将吡咯单体聚合在Nafion(R)117膜基体中.复合膜的红外光谱图中出现明显聚吡咯(PPy)的特征吸收峰,说明吡咯单体聚合在Nafion(R)117膜中.机械性能测试表明复合膜的拉伸强度比Nafion(R)117膜提高了.热重测试表明复合膜具有更高的热稳定性能.对复合膜进行了甲醇渗透性能的测试,结果表明复合膜具有明显的阻醇作用,PPy/NF-3膜的甲醇渗透率值是5.9×10-7cm2·s-1,和Nafion(R)117膜相比降低了53%.     

MOCVD法生长ZnO薄膜时氧源 t-BuOH和H2O的比较研究

以活性较低的叔丁醇(t-BuOH)和水(H₂O)作为氧源,采用MOCVD技术生长了ZnO薄膜。研究发现,t-BuOH作为氧源可以有效地抑制其与锌源之间的气相预反应,比H₂O作为氧源进行ZnO薄膜的外延生长具有更高的生长速率,得到的ZnO薄膜晶体质量更优,同时载流子的迁移率可以达到37.0 cm²·V^-1·s^-1, 表明t-BuOH更适合作为氧源通过MOCVD系统生长ZnO薄膜。     

a-C: Fe/AlOx/Si基异质结的光伏效应

使用脉冲激光沉积(PLD)依次沉积氧化铝和碳膜制备了a-C: Fe/AlO_x/Si基异质结,研究了其光伏效应及其在太阳能电池上的应用.该太阳能电池在标准日光照射(AM1.5,100 mW/cm²)下,可获得0.33 V的开路电压和4.5 mA/cm²的电流密度,太阳能电池的转换效率为0.35%.通过C-V测量,证明了氧化铝层的引入降低了界面能级数目,增加了界面势垒高度.界面能级数目降低减少了光生载流子在界面复合的 关键词： 光伏效应 非晶碳膜 异质结 氧化铝     

发光层厚度变化的高效红色有机电致磷光器件

以铱配合物红色磷光体为掺杂剂，制备了基于TPBi材料的红色电致磷光器件,其结构为ITO/CuPc/NPB/TPBi:Btp₂Ir(acac)/ TPBi/Alq/LiF/Al.取得了在x=0.62，y=0.35的色度下，效率最高达2.43cd/A；电流密度为20mA/cm²时，亮度431cd/m²；电流密度为400mA/cm²时，亮度4798 cd/m²的结果.讨论了不同的发光层厚度影响器件色度和 关键词： 三线态 红光掺杂剂 有机电致磷光 T-T湮没     

PPy/Nafion复合膜的制备及性能表征

用0.5mol.L-1的FeCl3溶液作引发剂,采用原位化学聚合法将吡咯单体聚合在Nafion117膜基体中。复合膜的红外光谱图中出现明显聚吡咯（PPy）的特征吸收峰,说明吡咯单体聚合在Nafion117膜中。机械性能测试表明复合膜的拉伸强度比Nafion117膜提高了。热重测试表明复合膜具有更高的热稳定性能。对复合膜进行了甲醇渗透性能的测试,结果表明复合膜具有明显的阻醇作用,PPy/NF-3膜的甲醇渗透率值是5.9×10^-7cm^2.s^-1,和Nafion117膜相比降低了53%。     

类金刚石和碳氮薄膜的电化学沉积及其场发射性能研究

利用电化学方法在室温下成功地沉积了类金刚石(DLC)薄膜和非晶CN_x薄膜，并 对制备条件进行了讨论.通过扫描电子显微镜、傅里叶变换红外光谱技术，分析了薄膜的表面形貌和化学结合状态.场发射测量结果表明：DLC膜和非晶CN_x的开启场分别为88和 10V/μm；并且在23V/μm的电场下，DLC膜和非晶CN_x膜的发射电流密度分别达到10 和037mA/cm². 关键词： 电化学沉积 类金刚石薄膜 x薄膜')" href="#">CN_x薄膜 场致电子发射     

掺硼水吸附碳纳米管电子场发射性能的第一性原理研究

运用第一性原理研究了掺硼碳纳米管(BCNT)顶端吸附水分子后的电子场发射性能.结果表明：掺B及吸附H₂O的碳纳米管(BCNT+H₂O)端部形成电子聚集的原子尺度微区,其电子态密度(DOS)在费米能级(E_f)附近有很大提高.根据计算的电子DOS,HOMO/LUMO及Mulliken电荷分布等可知BCNT+H₂O比CNT+H₂O有更好的场发射性能. 关键词： 掺硼碳纳米管 吸附 密度泛函理论 电子场发射     

双金属粒子在光–氢转换中的作用分析

本文采用两步阳极氧化法在TiO₂纳米环/管阵列表面负载Ag、Cu纳米粒子,与单金属修饰样品对比分析得到双金属对TiO₂光电响应和电极/电解液界面性质的影响。同时,XPS、UV-Vis和U-t测试表明AgCu-TiO₂光阳极金属抗氧化性强、可见光吸收好、光生电子寿命长,光电流密度达0.76 mA·cm^-2,对应产氢速率376μL·h^-1·cm^-2。对AgCu-TiO₂/H₂O、Ag-TiO₂/H₂O和Cu-TiO₂/H₂O体系进行分子动力学模拟计算,双金属体系相对较宽的耗尽层可促进光生电子–空穴分离、转移。最终结合热力学、动力学分析得到双金属修饰TiO₂光阳极的电子传输路径。     

几种易溶性有机溶剂水溶液的1H、13C、17O和31P NMR研究

本文用络合平衡及快交换的方法定量描述了磷酸三乙酯(TEP)、四氢呋喃(THF)、二氧六环(DO)和乙腈(AN)水溶液中化学位移随浓度变化的曲线。发现体系中未配位水的¹H化学位移与其浓度的关系为:H₂O δ₀=1.07+3.71e^{k(0.018-1)/[H₂O]}。K值与溶剂的供电性和分子量有关。溶剂破坏水结构的能力取决于它的供电性。     

Hydrothermal Synthesis of Nickel Phosphate Nanorods for High‐Performance Flexible Asymmetric All‐Solid‐State Supercapacitors

Ni₂₀[(OH)₁₂(H₂O)₆][(HPO₄)₈(PO₄)₄]·12H₂O nanorods are successfully synthesized via a one‐pot hydrothermal reaction. A high‐performance flexible asymmetric all‐solid‐state supercapacitor based on the obtained Ni₂₀[(OH)₁₂(H₂O)₆][(HPO₄)₈(PO₄)₄]·12H₂O nanorods (positive electrode) and graphene nanosheets (negative electrode) is successfully assembled. It is the first report of this nanomaterial applied for all‐solid‐state supercapacitors. Interestingly, a maximum volumetric energy density of 0.446 mW h cm^?3 at a current density of 0.5 mA cm^?2 and a maximum power density of 44.1 mW cm^?3 at a current density of 6.0 mA cm^?2 are achieved by the as‐assembled device. What's more, the device also shows excellent mechanical flexibility and little capacitance change after over 5000 charge/discharge cycles at a current density of 0.5 mA cm^?2.     

Preparation/Property Relationships for a Nitrate Amperometric Sensor: Effect of Nanowires Polymerization Parameters

Nitrate amperometric sensors based on polypyrrole (PPy) nanowire modified electrodes were developed by electropolymerization of pyrrole with a template‐free method. Polymerization parameters of PPy nanowires were changed to improve the amperometric response to NO₃ ^?. The experimental results show that the polymerization parameters such as concentration of pyrrole, concentration of electrolyte, acidity of polymerization solution, and the kinds and concentration of dopants have significant effects on the morphologies of the nanowires and the electroreduction current density of NO₃ ^?. The PPy nanowires prepared in a solution containing NO₃ ^? have an obvious “memory effect” for NO₃ ^?. The determination sensitivity and detection limit may be varied with the change of modification parameters. The PPy nanowire modified electrode prepared under a certain polymerization condition has good electrocatalytic effect toward electroreduction of NO₃ ^? and has good linearity between the electroreduction current density and the concentration of NO₃ ^?. The sensitivity and detection limit are 606.54 mA/M cm² and 9.98×10^?6 M, respectively.     

Effects of seed layer on the structure and property of zinc oxide thin films electrochemically deposited on ITO-coated glass

ZnO films with different morphologies were deposited on the ITO-coated glass substrate from zinc nitrate aqueous solution at 65 °C by a seed-layer assisted electrochemical deposition route. The seed layers were pre-deposited galvanostatically at different current densities (i_sl) ranging from −1.30 to −3.0 mA/cm², and the subsequent ZnO films had been done using the potentiostatic technique at the cathode potential of −1.0 V. Densities of nucleation centers in the seed layers varied with increasing the current density, and the ZnO films on them showed variable morphologies and optical properties. The uniform and compact nanocrystalline ZnO film with (0 0 2) preferential orientation was obtained on seed layer that was deposited under the current density (i_sl) of −1.68 mA/cm², which exhibited good optical performances.     

The anodization of ZK60 magnesium alloy in alkaline solution containing silicate and the corrosion properties of the anodized films

The anodization of ZK60 magnesium alloy in an alkaline electrolyte of 100 g/l NaOH + 20 g/l Na₂B₄O₇·10H₂O + 50 g/l C₆H₅Na₃O₇·2H₂O + 60g/l Na₂SiO₃·9H₂O was studied in this paper. The corrosion resistance of the anodic films was studied by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques and the microstructure and composition of films were examined by SEM and XRD. The influence of anodizing time was studied and the results show that the anodizing time of 60 min is suitable for acquiring films with good corrosion resistance. The influence of current density on the corrosion resistance of anodizing films was also studied and the results show that the film anodized at 20 mA/cm² has the optimum corrosion resistance. The film formed by anodizing in the alkaline solution with optimized parameters show superior corrosion resistance than that formed by the traditional HAE process. The XRD pattern shows that the components of the anodized film consist of MgO and Mg₂SiO₄.     

Current density dependence of changes in the microstructure of SOFC anodes during electrochemical oxidation

The effect of current density during electrochemical oxidation on the microstructure of solid oxide fuel cell anodes was investigated. Anode-supported cells were subjected to electrochemical oxidation by oxide ions and chemical reduction by H₂ gas. Two anodes were electrochemically oxidized by the same quantity of electricity of 15 C using different current densities of 25 mA/cm² and 250 mA/cm². When Ni particles were oxidized at 25 mA/cm², little morphological change occurred in the Ni particles, resulting in only a small change in the microstructure of the anode. On the other hand, when Ni particles were oxidized at 250 mA/cm², the morphology of the particles changed to a more textured outer surface and the Ni particle seemed to divide into smaller ones. Neither cell showed a decrease in open circuit voltage nor cracks in the electrolyte, resulting in that the microstructure changes observed in the tested cells were caused by electrochemical oxidation and subsequent reduction (redox cycle). Furthermore, this suggests that the differences in the resulting microstructures of the Ni particles were caused by the differences in current density during electrochemical oxidation.     

Simple solar cells of 3.5% efficiency with antimony sulfide‐selenide thin films

Thin films of antimony sulfide‐selenide solid solutions (Sb₂S_x Se_3–x) were prepared by chemical bath deposition and thermal evaporation to constitute solar cells of a transparent conductive oxide (FTO)/CdS/Sb₂S_x Se_3–x/C–Ag. The cell parameters vary depending on the sulfide‐selenide composition in the films. The best solar cell efficiency of 3.6% was obtained with a solid solution Sb₂S_1.5Se_1.5 prepared by thermal evaporation of the precipitate for which the open circuit voltage is 0.52 V and short circuit current density, 15.7 mA/cm²under AM 1.5G (1000 W/m²) solar radiation. For all‐chemically deposited solar cells of Sb₂S_1.1Se_1.9 absorber, these values are: 2.7%, 0.44 V, and 15.8 mA/cm², and for Sb₂S_0.8Se_2.2, they are: 2.5%, 0.38 V and 18 mA/cm². (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Effects of annealing temperature on GO–Cu2O composite films grown by electrochemical deposition for PEC photoelectrode

In this work, graphene oxide–cuprous oxide (GO–Cu₂O) composite films were grown on fluorine-doped tin oxide substrates by electrochemical deposition. We investigated the effects of the annealing temperature on the morphological, structural, optical and photoelectrochemical (PEC) properties of GO–Cu₂O composite films. As a result, our work shows that while GO–Cu₂O composite films exhibit the highest XRD (111) peak intensity at 300 °C sample, the highest photocurrent density value obtained was −4.75 mA/cm² at 200 °C sample (using 0.17 V versus a reversible hydrogen electrode (RHE)). In addition, a reduction reaction at 300 °C sample was observed using XPS analysis from the shift in the O1s peak in addition to a weaker O1s peak intensity.     

钛离子辐照对MgB2超导薄膜的载流能力和磁通钉扎能力的影响

利用混合物理化学气相沉积法(hybrid physical-chemical vapor deposition, HPCVD)可以制备出高性能的MgB₂超导薄膜, 再对薄膜进行钛(Ti)离子辐照处理.经过辐照处理后的样品被掺入了Ti元素, 与未处理的干净MgB₂样品相比,其超导转变温度没有出现大幅度的下降, 而在外加磁场下的临界电流密度得到了明显的提高,同时样品的上临界磁场也得到了提高. 在温度5 K, 外加垂直磁场为4 T的情况下, Ti离子辐照剂量为1× 10¹³/cm²的样品的临界电流密度达到了1.72× 10⁵ A/cm², 比干净的MgB₂要高出许多,而其超导转变温度仍能维持在39.9 K的较高水平.     

Facile Construction of 3D Reduced Graphene Oxide Wrapped Ni3S2 Nanoparticles on Ni Foam for High‐Performance Asymmetric Supercapacitor Electrodes

3D reduced graphene oxide (rGO)‐wrapped Ni₃S₂ nanoparticles on Ni foam with porous structure is successfully synthesized via a facile one‐step solvothermal method. This unique structure and the positive synergistic effect between Ni₃S₂ nanoparticles and graphene can greatly improve the electrochemical performance of the NF@rGO/Ni₃S₂ composite. Detailed electrochemical measurements show that the NF@rGO/Ni₃S₂ composite exhibits excellent supercapacitor performance with a high specific capacitance of 4048 mF cm^?2 (816.8 F g^?1) at a current density of 5 mA cm^?2 (0.98 A g^?1), as well as long cycling ability (93.8% capacitance retention after 6000 cycles at a current density of 25 mA cm^?2). A novel aqueous asymmetric supercapacitor is designed using the NF@rGO/Ni₃S₂ composite as positive electrode and nitrogen‐doped graphene as negative electrode. The assembled device displays an energy density of 32.6 W h kg^?1 at a power density of 399.8 W kg^?1, and maintains 16.7 W h kg^?1 at 8000.2 W kg^?1. This outstanding performance promotes the as‐prepared NF@rGO/Ni₃S₂ composite to be ideal electrode materials for supercapacitors.