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111.
Rui Lin Matthew Wright Bin Gong Kah Howe Chan Murad J. Y. Tayebjee Ashraf Uddin 《固体物理学:研究快报》2014,8(11):904-907
Vertical phase separation of the polymer and fullerene molecules in bulk heterojunction organic solar cells influences the exciton dissociation, charge carrier transport and collection. This work compares the vertical phase separation of poly[2,1,3‐benzothiadiazole‐4,7‐diyl[4,4‐bis(2‐ethylhexyl)‐4H‐cyclopenta [2,1‐b:3,4‐b′]dithiophene‐2,6‐diyl]] (C‐PCPDTBT):[6,6]‐phenyl C71 butyric acid methyl ester (PC71BM) and poly[2,1,3‐benzothiadiazole‐4,7‐diyl[4,4‐bis(2‐ethylhexyl)‐4H‐cyclopenta [2,1‐b:3,4‐b′]dithiophene‐siloe2,6‐diyl]] (Si‐PCPDTBT):PC71BM blend films, using X‐ray photoemission spectroscopy depth profiles. The difference between the two polymers is the bridging atom, which is carbon for C‐PCPDTBT and silicon for Si‐PCPDTBT. Si‐PCPDTBT exhibits enhanced polymer chain packing and crystallinity. We believe this enhanced chain packing provides a driving force during film drying which alters the vertical morphology. The different nature of vertical phase separation plays a role in determining the increased device performance observed for Si‐PCPDTBT:PC71BM solar cells. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
112.
We introduce a broad class of self-similar processes {Z(t),t≥0} called generalized Hermite processes. They have stationary increments, are defined on a Wiener chaos with Hurst index H∈(1/2,1), and include Hermite processes as a special case. They are defined through a homogeneous kernel g, called the “generalized Hermite kernel”, which replaces the product of power functions in the definition of Hermite processes. The generalized Hermite kernels g can also be used to generate long-range dependent stationary sequences forming a discrete chaos process {X(n)}. In addition, we consider a fractionally-filtered version Zβ(t) of Z(t), which allows H∈(0,1/2). Corresponding non-central limit theorems are established. We also give a multivariate limit theorem which mixes central and non-central limit theorems. 相似文献
113.
Mori M Itabashi H Helaleh MI Kaczmarski K Głód B Kowalska T Xu Q Ikedo M Hu W Tanaka K 《Journal of chromatography. A》2006,1118(1):41-45
Vacancy ion-exclusion chromatography (VIEC) for inorganic acids such as H(2)SO(4), HCl, H(3)PO(4), HNO(3), HI and HF is tested on a polymethacrylate-based weakly acidic cation-exchange resin column in the H(+)-form. That is, mixture of inorganic acids in the mobile phase is adsorbed to the resin phase passing through the separation column, and each vacant peak induced by injecting water is determined. Retention times are dependent on the degrees of retention for each analyte in the resin phase. In VIEC, well-shaped peaks of inorganic acids are produced, leading to efficient separations. However, retention behaviors of inorganic acids were strongly affected by the concentrations of the acids in the mobile phase. Sulfosalicylic acid was mixed with inorganic acids in the mobile phase prior to the introduction of a separation column in order to obtain the well-resolutions in the lower concentrations of the acids. By using this method, the separations of inorganic acids could be achieved in the range of 0.01-1 mM, and the linear ranges could be extended over two-orders of magnitude. This is considered since the protonated carboxylic groups fixed on the resin phase were increased with increasing the acid concentrations in the mobile phase, and the penetration effects for the acids to the resin phase were thus enhanced. The detection limits (S/N=3) were below 1.0 microM for all analyte acids. Precision values for retention times were below 0.32% and for peak area were below 0.91%. 相似文献
114.
A teaching experiment was conducted to investigate the effect of journal writing on achievement in and attitudes toward mathematics. Achievement variables included conceptual understanding, procedural knowledge, problem solving, mathematics school achievement, and mathematical communication. Subjects were selected from first intermediate students (11–13 years) attending the International College, Beirut, Lebanon, where either English or French is the language of mathematics instruction. The journal-writing (JW) group received the same mathematics instruction as the no-journal-writing (NJW) group, except that the JW group engaged in prompted journal writing for 7 to 10 minutes at the end of each class period, three times a week, for 12 weeks. The NJW group engaged in exercises during the same period. The results of ANCOVA suggest that journal writing has a positive impact on conceptual understanding, procedural knowledge, and mathematical communication but not on problem solving, school mathematics achievement, and attitudes toward mathematics. Gender, language of instruction, mathematics achievement level, and writing achievement level failed to interact with journal writing. Student responses to a questionnaire indicated that students found journal writing to have both cognitive and affective benefits. 相似文献
115.
116.
A. Murad D. Alshamsi X. L. Hou F. Al Shidi R. Al Kendi A. Aldahan 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(3):1653-1660
Characterizing the quality and radioactivity of groundwater is vital as it represents valuable resource in arid regions. Here we present radioactivity level in groundwater collected from wells in a region along the border between Sultanate of Oman and United Arab Emirates (UAE). The aquifers are alluvium deposits (silt, sand and gravel) and the measured groundwater radioactivity (including 232Th, 238U, 235U, 226Ra, 222Rn, gross-α and gross-β) indicates values below the WHO permissible limits for drinking water. The results also show large difference in radioactivity fingerprints, in particular for 226Ra and 222Rn within the investigated aquifers. The data further indicate lower radioactivity in groundwater of the alluviums compared to the carbonate aquifers in the region. This feature makes the alluvium aquifers valuable reservoirs that should be carefully exploited as a source of groundwater. As this is the first investigation on the radioactivity of groundwater in alluvial aquifers in the region, it suggests that other alluvial deposits, particularly those inland and far from the marine water intrusion or seepage from carbonate rocks would have low radioactivity fingerprints. 相似文献
117.
The Hermite rank appears in limit theorems involving long memory. We show that a Hermite rank higher than one is unstable when the data is slightly perturbed by transformations such as shift and scaling. We carry out a “near higher order rank analysis” to illustrate how the limit theorems are affected by a shift perturbation that is decreasing in size. We also consider the case where the deterministic shift is replaced by centering with respect to the sample mean. The paper is a companion of Bai and Taqqu (2017) which discusses the instability of the Hermite rank in the statistical context. 相似文献
118.
Mehtab Parveen Raza Murad Ghalib Mahboob Alam Monika Singh 《Journal of Saudi Chemical Society》2013,17(3):303-305
The phenanthren skeleton, named as Peltophorin was isolated from methanolic extraction of the leaves of Peltophorum vogelianum. The structure was elucidated on the basis of chemical and physical evidence (IR, UV, 1H NMR, 13C NMR) and further confirmed X-ray analysis. 相似文献
119.
Ji Kaifang Chen Xuegao Aldahan Ala Yi Peng Murad Ahmed Hussein Saber Alshamsi Dalal Mohamed Mohamed M. Yu Zhongbo 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(3):1469-1470
Journal of Radioanalytical and Nuclear Chemistry - In the original publication of the article, the eighth author’s name and Figure 1 were published incorrectly. 相似文献
120.
We classify all orthonormal wavelets which occur in theL2space of the faces of a platonic solid. 相似文献