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71.
EDOT‐diketopyrrolopyrrole copolymers for high bulk hole mobility and near infrared absorption 下载免费PDF全文
Christian J. Mueller Chetan R. Singh Mukundan Thelakkat 《Journal of Polymer Science.Polymer Physics》2016,54(6):639-648
To obtain novel low‐bandgap materials with tailored hole‐transport properties and extended absorption, electron rich 3,4‐ethylenedioxythiophene is introduced as a comonomer in diketopyrrolo[3,4‐c]pyrrole copolymers with different aryl flanking units. The polymers are characterized by absorption and photoluminescence spectroscopy, dynamic scanning calorimetry, cyclic voltammetry, and X‐ray diffraction. The charge transport properties of these new materials are studied carefully using an organic field effect transistor geometry where the charge carriers are transported over a narrow channel at the semiconductor/dielectric interface. These results are compared to bulk charge carrier mobilities using space‐charge limited current (SCLC) measurements, in which the charge carrier is transported through the complete film thickness of several hundred nanometers. Finally, charge carrier mobilities are correlated with the electronic structure of the compounds. We find that in particular the thiophene‐flanked copolymer PDPP[T]2‐EDOT is a very promising candidate for organic photovoltaics, showing an absorption response in the near infrared region with an optical bandgap of 1.15 eV and a very high bulk hole mobility of 2.9 × 10?4 cm2 V?1 s?1 as measured by SCLC. This value is two orders of magnitudes higher than SCLC mobilities reported for other polydiketopyrrolopyrroles and is in the range of the well‐known hole transporting polymer poly(3‐hexylthiophene). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 639–648 相似文献
72.
We expand the picture of plasmon hybridization in metamagnetic structure via numerically studying the electromagnetic coupling in the metallic cut-wire-pair super cells. It is shown that a triple negative permeability band can be achieved by systematically controlling the plasmon hybridization in such the structure. The corresponding transmission properties as well as the electromagnetic responses of the plasmon-hybridized structures were presented by using the finite integration technique simulations. Our results would reveal a promising design to obtain the multiple negative refractions based on the combination of hybridized cut-wire-pairs and continuous wires. 相似文献
73.
基于Drude模型研究了异向介质的色散磁导率对调制不稳定性的影响. 结果表明,在反常色散情形,赝五阶非线性在异向介质的负折射区中增大了调制频谱的范围及增益值,这与常规正折射介质中出现的现象正好相反;自陡峭效应在异向介质中有可能为负值,但无论正负,也无论在正折射区还是负折射区,它都抑制调制不稳定性的产生;二阶非线性色散效应在正、负折射区中分别促进和抑制调制不稳定性的产生. 在正常色散情形,由于二阶非线性色散效应的作用,使本来在常规正折射介质中不可能出现的调制不稳定性现象也能出现,这一特性为在正常色散区形成孤 相似文献
74.
提出了一种新结构的高功率径向强流速调管振荡器,该器件利用折叠式同轴谐振腔的微波场与接近空间电荷限制电流的径向电子束强烈相互作用产生高功率微波。首先对这种器件的实现机理进行了初步的分析,提出了有间隙电压情况时的径向同轴间隙的空间电荷限制电流1维近似估计模型。分析表明:对于电子束直流接近但小于直流空间限制电流的径向速调管,当有调制间隙电压时,空间限制电流要小于无调制间隙电压情况下的直流空间限制电流,径向强流电子束电流接近和超过空间电荷限制电流时会出现强烈的调制。然后用PIC程序对其特性进行了粒子模拟,在二极管输入电压500 kV、电子束电流为30 kA条件下,最终得到了峰值功率6 GW、频率1.3 GHz的微波输出。 相似文献
75.
用电沉积方法得到了不同浓度硫酸锌电解液的分形凝聚图像;进行图像处理,得到了其分形维数与浓度的关系曲线;用粒子扩散限制凝聚模型解释了此关系 相似文献
76.
Xin?YangEmail author Mali?Gong Lei?Huang Ping?Yan Haitao?Zhang 《Optical and Quantum Electronics》2004,36(12):1079-1088
In this paper, the authors investigate the performance of recently presented run-length limited (4, 18) code for high density optical storage systems. The construction of the code is described simply. The code has code rate R = 1/3 and density ratio (DR) = 1.67. The bit error rate (BER) performance for decision feedback equalizer (DFE) and partial response maximum likelihood (PRML) detector are simulated, considering signal-to-noise ratio (SNR) and optical channel jitter. The result shows that the performance of the code is acceptable. The encoder and decoder of the code are implemented by complex programmable logic device (CPLD) chip and the hardware resources required for encoder and decoder arelow. 相似文献
77.
Beynon RJ 《Journal of mass spectrometry : JMS》2004,39(2):188-192
In a recent paper, Villaneuva et al. (J. Mass Spectrom. 2002; 37: 974) described the use of exoproteases as probes of higher order structure in proteins. Their model assumes that the proteins are attacked sequentially from either the N-terminus or the C-terminus, depending on the type of exoprotease (aminopeptidase or carboxypeptidase) used. The products of this presumed exoproteolysis were then analysed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The pattern of fragments obtained was mapped on to the primary sequence of the protein, and the exoproteolysis was interpreted as comprising a series of fast and slow phases, the rates of the different phases being directly related to the higher order structure of particular segments of the protein. Here, it is shown that this explanation is unlikely, that both kinetic and practical considerations suggest that alternative explanations for the data should be sought, and that exoproteolysis will perhaps not be as valuable as a conformational probe as the authors suggest. 相似文献
78.
采用多晶材料趋近饱和定律研究了非晶Fe39.4-xCo40Si9B9Nb2.6Cux(x=0.5,1,1.5) 合金在不同温度纳米晶化后的有效磁各向异性常数〈K〉.结果表明, Cu含量较低(x=0.5)时,纳米晶粒较大并且在较低的退火温度(550℃)下析出硬磁相,〈K〉随退火温度Ta升高显著增加;随着Cu含量的增加,有效地细化了晶粒,并且抑制了硼化物的析出,〈K〉明显减小.讨论了〈K〉与晶粒尺寸D及初始磁导率的关系.
关键词:
纳米晶
有效磁各向异性
磁导率
FeCo基合金 相似文献
79.
80.
Hua Su Huaiwu ZhangXiaoli Tang Yulan JingYingli Liu 《Journal of magnetism and magnetic materials》2007
Effects of composition and sintering temperature on grain size, porosity and magnetic properties of the NiZn and NiCuZn ferrites were investigated. It was found that the lowest power loss could be obtained with the equimolar composition for both NiZn and NiCuZn ferrites, which could be attributed to the lowest porosity. A slight deficiency or excess of Fe2O3 content had no pronounced influence on saturation magnetic flux density (Bs) in our testing range. However, a slight excess of Fe2O3 was effective to improve the initial permeability, which could be attributed to decrease of the magnetocrystalline anisotropy. With the increase of sintering temperature, the initial permeability and power loss of the NiZn and NiCuZn ferrites had different development trend, which could be explained by the different variation trend of the grain size and porosity. Power losses of the NiCuZn ferrite samples were lower than that of the NiZn ferrite samples at any sintering temperature. Synthetically, the NiCuZn ferrites had a better performance than the NiZn ferrites in power field use. 相似文献