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61.
A. Kadashchuk A. Andreev H. Sitter N.S. Sariciftci Y. Skryshevski Y. Piryatinski I. Blonsky D. Meissner 《Advanced functional materials》2004,14(10):970-978
We report on photoluminescence (PL) and thermally stimulated luminescence (TSL) in highly ordered nanostructures of para‐sexiphenyl (PSP) grown by hot wall epitaxy (HWE). A low‐energy broad band is observed in the PL spectra that can be attributed to the emission from molecular aggregates. While the intrinsic exciton emission in steady‐state PL dominates at low temperatures, the emission from aggregates increases with elevating temperature and its magnitude depends sensitively on film preparation conditions. Time‐resolved PL measurements showed that the aggregate emission decays with a life‐time of ≈ 4 ns, which is approximately an order of magnitude larger than the lifetime of singlet excitons. TSL data suggests the presence of an energetically disordered distribution of localized states for charge carriers in PSP films, which results from an intrinsic disorder in this material. A low‐temperature TSL peak with the maximum at around 30 K evidences for a weak energy disorder in PSP films, and has been interpreted in terms of a hopping model of TSL in disordered organic materials. 相似文献
62.
Unconrolled agglomeration of particles and adhesion of the particulate mass to wall surfaces are common severe problems in many drying operations. This paper reviews the mechanisms of interparticle and particle-surface attraction as well as the theory and the existing tests for characterising powders in terms of internal strength, wall friction and adhesion. The usefulness of the information obtained from these tests in dryer design and operation is critically reviewed. The importance of powder stickiness in various types of dryers is discussed and established methods of combating the problem are presented Recommendations an made for further research in the area of powder cohesion and adhesion. 相似文献
63.
东荣三矿冻结段井壁破坏原因简析 总被引:1,自引:0,他引:1
介绍了东荣三矿主井、副井、东风井三个井筒冻结段井壁的施工及破坏情况,并针对破坏的原因进行了分析,同时对冻结段的井壁结构型式提出了建议。 相似文献
64.
本文提出一种可控环量船用翼数值模拟方法,其计算结果与最近Mclachlan的试验数据十分吻合。通过本文的计算,对广泛引用的Kind & Maull的二维试验数据提出了修正。根据本文所作的三维可控环量帆翼的试验结果,与二维计算值的比较,指出它们之间所存在的显著差别。 相似文献
65.
运用文献[1]所介绍的分析原理与方法,编制了强震作用下钢筋混凝土框架-剪力墙结构非线性地震反应时程分析的程序。本文介绍该程序的功能、框图,以及利用该程序计算所得到的几栋钢筋混凝土结构的非线性地震反应分析结果。算例表明,本程序计算结果可靠,能很好地用于解释震害和预测地震时结构可能发生的破坏。 相似文献
66.
圆筒形铸件缩松缩孔的产生原因及解决方法 总被引:1,自引:0,他引:1
针对圆筒形铸铁辊体冒口端面产生的缩松、缩孔缺陷,进行了举例说明、系统分析,找到了缺陷产生的原因及影响因素。通过解决措施的应用与实施,有效地克服了圆筒形辊体铸件冒口端面产生的缩松、缩孔缺陷,同时应用到其它大型圆筒形铸件中,都得到了良好效果。 相似文献
67.
Periklis E. Ergatis Panagiotis G. Massouros Georgia C. Athanasouli George P. Massouros 《国际能源研究杂志》2003,27(9):795-811
A time‐dependent coefficient of heat transfer is proposed for the computation of thermal power required, so that a room temperature reaches a desired value within a given time. A mathematical formulation of the room heating transient phenomenon is constructed in a dimensionless form. Using an integral approximate solution an analytical expression for this coefficient is provided and it is verified by diagrams adopted by DIN 4701. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
68.
Alignment of single wall carbon nanotubes (SWNT) in liquid crystalline (LC) polymer matrix imparting orientation to the nanotubes along the nematic director was studied by atomic force microscopy, measurements of electrical conductivity and Raman spectroscopy of the composite in the directions parallel and perpendicular to the nematic director. The composites were prepared through dispersion of SWNT with LC monomer in a common solvent, their alignment in nematic monomer and consequent UV polymerization of the monomer. The anisotropy of electrical and optical properties of the system depends strongly on the concentration of the nanotubes in the range of 1-10% SWNT being especially strong for smaller concentrations and negligible at higher loads. A simple semi-quantitative model is suggested to account for the orientational behavior of nanotubes in nematic matrices. It successfully describes the observed anisotropy of physical properties at microscale (up to 200 μm) in terms of anchoring of the polymer chains to the nanotubes surface and adjustment of the nanotubes orientation to the nematic direction due to such coupling. The increasing disorientation of the nematic domains at higher nanotubes loads is explained as a development of larger number of LC defects induced by the nanotubes in the nematic matrix due to their intrinsic nature of aggregation. The anisotropy of physical properties at macro scale (several millimeters) is much smaller and less dependable on SWNT concentration because differently oriented LC domains effectively wash out the anisotropy. 相似文献
69.
70.