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51.
针对目前商用日盲紫外/可见光双谱段电晕探测仪对故障的判定效率低且容易受噪声干扰问题,本文提出了一种微弱日盲紫外电晕自动实时检测方法。在分析电晕目标和噪声时间域统计特性的基础上,该方法利用电晕目标在时间域连续的特点,首先完成灰度图像二值化、形态学膨胀等预处理,其次将N帧连续图像累加后阈值化,最后进行特征提取,获取电晕位置、面积等特征信息,实现电晕的自动实时检测。在完成设备辐射标定的基础上,可立即回溯得到故障的光子计数参考值。建立了该方法的探测概率、虚警率数学模型。将其在高速数字处理平台TMS320DM642上实现并输入测试视频,结果表明:在典型参数情况下该方法单次检测虚警概率为2.85×10-5,处理时间小于120 ms,可实现微弱日盲紫外电晕的实时检测。 相似文献
52.
研究了一种新型纳米铂修饰玻碳电极的制备方法,并对其电化学催化性能进行了研究。实验结果表明,通过电沉积前在金刚石粉末悬浊液中对玻碳电极进行超声处理,可制备出新型玻碳电极。经超声处理后,金刚石颗粒在玻碳电极基体上产生了数微米长的划痕。电沉积过程中,在该电极上可沉积分布较密集的平均尺寸为110nm的Pt颗粒。这种新型纳米铂修饰玻碳电极的表面电化学活性值为0.397 m2/g,高于普通铂修饰玻碳电极,且在0.5 mol/L H2SO4溶液中具有良好的电化学稳定性。 相似文献
53.
Stabilization of Catalytically Active Cu+ Surface Sites on Titanium–Copper Mixed‐Oxide Films
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Dr. Ashleigh E. Baber Dr. Xiaofang Yang Dr. Hyun You Kim Dr. Kumudu Mudiyanselage Markus Soldemo Dr. Jonas Weissenrieder Dr. Sanjaya D. Senanayake Dr. Abdullah Al‐Mahboob Dr. Jerzy T. Sadowski Dr. Jaime Evans Dr. José A. Rodriguez Dr. Ping Liu Dr. Friedrich M. Hoffmann Dr. Jingguang G. Chen Dr. Darío J. Stacchiola 《Angewandte Chemie (International ed. in English)》2014,53(21):5336-5340
The oxidation of CO is the archetypal heterogeneous catalytic reaction and plays a central role in the advancement of fundamental studies, the control of automobile emissions, and industrial oxidation reactions. Copper‐based catalysts were the first catalysts that were reported to enable the oxidation of CO at room temperature, but a lack of stability at the elevated reaction temperatures that are used in automobile catalytic converters, in particular the loss of the most reactive Cu+ cations, leads to their deactivation. Using a combined experimental and theoretical approach, it is shown how the incorporation of titanium cations in a Cu2O film leads to the formation of a stable mixed‐metal oxide with a Cu+ terminated surface that is highly active for CO oxidation. 相似文献
54.
A new luminescent Zn(II) compound, [Zn(pbdc)0.5(mtz)(DMPU)]n(1, H2pbdc = terephthalic acid, Hmtz = 5-methyl-1H-tetrazole, DMPU = N,N'-dimethylpropyleneurea), has been urothermally synthesized and characterized by elemental analysis, IR, X-ray powder diffraction(PXRD) and single-crystal X-ray diffraction. The title compound crystallizes in orthorhombic Pbca space group with a = 17.2649(5), b = 10.4680(3), c = 17.4457(7) ?, V = 3152.94(18) ?3, C12H17N6O3Zn, Mr = 358.71, Z = 8, Dc = 1.511 g/cm3, F(000) = 1480, μ = 1.579 mm-1, the final R = 0.0379 and wR = 0.0971 for 2785 observed reflections(I 2?(I)). Single-crystal X-ray structural analysis reveals that compound 1 features a 2D undulated layer with a 3-connected hcb topology. Moreover, the luminescent properties of 1 have also been investigated in the solid-state at room temperature. 相似文献
55.
Xiaofang Lu Qi Zheng Shijia Gu Rui Guo Li Su Jiancheng Wang Zhenxing Zhou Yuchi Fan Wan Jiang Lianjun Wang 《中国化学快报》2020,31(3):880-884
Cu@Ag/Bi2Te3 nanocomposites were prepared for the first time by ultrasonic dispersion-rapid freezedrying method combined with spark plasma sintering(SPS).By changing the content of Cu@Ag nanoparticle,we could modulate the temperature dependent thermoelectric properties.The highest ZT value can be obtained at 450 K for 1 vol%Cu@Ag/Bi2Te3,which is benefited from the decoupling of electrical and thermal properties.With the increase of electrical conductivity,the absolute value of Seebeck coefficient lifts while the thermal conductivity declines.Meanwhile,the average ZT value between 300 K and 475 K was 0.61 for 1 vol%Cu@Ag/Bi2Te3,which is much higher than that of pristine Bi2 Te3.Therefore,the decoupling effect of Cu@Ag nanoparticles incorporation could be a promising method to broaden the application of Bi2Te3 based thermoelectric materials. 相似文献
56.
将SnO2负载在碳球上通过不完全烧结的方法得到含有大量碳的空心状C@SnO2,随后加入TAA(硫代乙酰胺),利用离子交换法在水热过程中制备了具有不同硫化程度的空心结构的C@SnO2@SnS2三元复合物。利用XRD、FESEM、TEM、XPS、UV-Vis DRS、PL等测试手段对合成样品进行表征,并测试了其光催化去除Cr(VI)的性能。结果表明,C、SnO2和SnS2三者之间的协同作用以及空心结构的形貌显著增强了SnO2的光催化性能,其中CSS-2样品对Cr(VI)具有最佳的去除能力,太阳光照射120 min后对Cr(VI)的去除率高达98.8%。 相似文献
57.
Katsuhiko Ariga Xiaofang Jia Jingwen Song Jonathan P. Hill David Tai Leong Yi Jia Junbai Li 《Angewandte Chemie (International ed. in English)》2020,59(36):15424-15446
Incorporation of non‐equilibrium actions in the sequence of self‐assembly processes would be an effective means to establish bio‐like high functionality hierarchical assemblies. As a novel methodology beyond self‐assembly, nanoarchitectonics, which has as its aim the fabrication of functional materials systems from nanoscopic units through the methodological fusion of nanotechnology with other scientific disciplines including organic synthesis, supramolecular chemistry, microfabrication, and bio‐process, has been applied to this strategy. The application of non‐equilibrium factors to conventional self‐assembly processes is discussed on the basis of examples of directed assembly, Langmuir–Blodgett assembly, and layer‐by‐layer assembly. In particular, examples of the fabrication of hierarchical functional structures using bio‐active components such as proteins or by the combination of bio‐components and two‐dimensional nanomaterials, are described. Methodologies described in this review article highlight possible approaches using the nanoarchitectonics concept beyond self‐assembly for creation of bio‐like higher functionalities and hierarchical structural organization. 相似文献
58.
Electrocatalytic water splitting to produce hydrogen and oxygen is regarded as one of the most promising methods to generate clean and sustainable energy for replacing fossil fuels. However, the design and development of an efficient bifunctional catalyst for simultaneous generation of hydrogen and oxygen remains extremely challenging yet is critical for the practical implementation of water electrolysis. Here, we report a facile method to fabricate novel N‐doped carbon nanotube frameworks (NCNTFs) by the pyrolysis of a bimetallic metal organic framework (MIL‐88‐Fe/Co). The resultant electrocatalyst, Co3Fe7@NCNTFs, exhibits excellent oxygen evolution reaction (OER) activity, achieving 10 mA/cm2 at a low overpotential of just 264 mV in 1 M KOH solution, and 197 mV for the hydrogen evolution reaction. The high electrocatalytic activity arises from the synergistic effect between the chemistry of the Co3Fe7 and the NCNTs coupled to the novel framework structure. The remarkable electrocatalytic performance of our bifunctional electrocatalyst provides a promising pathway to high‐performance overall water splitting and electrochemical energy devices. 相似文献
59.
General expressions used for transforming raw laser-induced fluorescence (LIF) intensity into the population and alignment parameters of a symmetric top molecule are derived by employing the density matrix approach. The molecular population and alignment are described by molecular state multipoles. The results are presented for a general excitation-detection geometry and then applied to some special geometries. In general cases, the LIF intensity is a complex function of the initial molecular state multipoles, the dynamic factors and the excitation-detection geometrical factors. It contains a population and 14 alignment multipoles. How to extract all initial state multipoles from the rotationally unresolved emission LIF intensity is discussed in detail. 相似文献
60.