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991.
992.
Organic light-emitting diodes were fabricated with a structure of indium-tin-oxide (ITO)/poly(N-vinylcarzole)(PVK):4-(dicyanom-ethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB)/8-tris-hydroxyquinoline aluminum (Alq3)/lithium fluoride (LiF)/Al. The energy transfer from PVK to Alq3 then to DCJTB and the charge trapping processes were investigated by employing the photoluminescence (PL) and electroluminescence (EL) spectra. With increasing thickness of the Alq3 layer, the PL and EL emission from PVK were decreased gradually, which indicated that the effective energy transfer occurred from PVK to Alq3 and then from Alq3 to DCJTB. At the same time, we found that the exciton recombination zone could be adjusted by controlling the Alq3 layer thickness and the applied voltages. The effects of different DCJTB concentrations on the optical and electrical characteristics of the devices were investigated, and an obvious red-shift was observed with the DCJTB dopant concentrations increasing in the PL and EL spectra. 相似文献
993.
用溶胶-凝胶方法制备了TiO2纳米样品,并对该样品在300℃到800℃温度区域进行了退火处理.应用同步辐射X射线粉末衍射(XRD)方法研究了经不同热处理温度的TiO2纳米颗粒的结构相变.应用同步辐射小角X射线散射(SAXS)方法研究了TiO2纳米颗粒的表面分形与界面特性.得到纳米颗粒粒度与退火温度的变化规律,讨论了表面界面特征与相变的关系.
关键词:
X射线小角散射
X射线衍射
2纳米颗粒')" href="#">TiO2纳米颗粒 相似文献
994.
We propose the enhancement of Lambdac as a novel quark-gluon plasma signal in heavy ion collisions at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider. Assuming a stable bound diquark state in the strongly coupled quark-gluon plasma near the critical temperature, we argue that the direct two-body collision between a c quark and a [ud] diquark would lead to an enhanced Lambdac production in comparison with the normal three-body collision among independent c, u, and d quarks. In the coalescence model, we find that the Lambdac/D yield ratio is enhanced substantially due to the diquark correlation. 相似文献
995.
A. Chrobak G. Haneczok D. Chrobak Ł. Madej G. Chełkowska M. Kulpa 《Journal of magnetism and magnetic materials》2008
The paper presents measurements of magnetic permeability, magnetic after-effects, magnetostriction, DSC and XPS for the Fe80Nb6B14 amorphous alloys preliminary annealed for 1 h at temperatures ranging from 300 to 770 K. It was shown that annealing out of free volume and internal stresses causes a decrease of magnetostriction coefficient and leads to the formation of the energetically stable relaxed amorphous state. The XPS spectra show local fluctuation of boron density. This effect was attributed to the formation of small iron clusters—the characteristic feature for the relaxed amorphous phase. 相似文献
996.
Mohd Zaki Mohd Yusoff Zainuriah Hassan Chin Che Woei Haslan Abu Hassan 《化学物理学报(中文版)》2010,23(4):431-436
We investigated growth of GaN pn-junction layers grown on silicon(111) by plasma-assisted molecular beam epitaxy system and its application for photo-devices. Si and Mg were used as n- and p-dopants, respectively. The reflection high energy electron diffraction images indicated a good surface morphology of GaN pn-junction layer. The thickness of GaN pn-junctions layers was about 0.705 nm. The absence of cubic phase GaN showed that this layer possessed hexagonal structure. According to XRD symmetric rocking curve ω/2θ scans of (0002) plane at room temperature, the full width at half-maximun of GaN pn-junction sample was calculated as 0.34o, indicating a high quality layer of GaN pn-junction. Surprisingly, there was no quenching of the A1(LO) peak, with the presence of Si- and Mg-dopants in sample. The pn-junctions sample has a good optical quality which was measured by thephotoluminescence system. For photo-devices applications, Ni and Al were used as front and back contacts, respectively. The current-voltage characteristics of the devices showed the typical rectifying behavior of heterojunction. The photo-current measurement was performed using a visible-lamp under forward and reverse biases. From the temperature-dependent measurements, the current at low bias exhibited much stronger temperature dependence and weaker field dependence. The effect of thermal annealing on front contact Ni was also carried out. The front contact Ni was annealed at 400 and 600 oC for 10 min in the nitrogen ambient. The results showed that 600 oC treated sample had a higher gain at 1.00 V/e than 400 oC treated and untreated samples. 相似文献
997.
A. V. Fokin Yu. N. Studnev A. I. Rapkin Nguen Che Ngem D. V. Zagorevskii 《Russian Chemical Bulletin》1984,33(7):1443-1446
Conclusions The reaction of perfluoromethylvinyl ether with halofluorosulfates and polyfluoroalkyl hypochlorites was investigated. In going from halofluorosulfates to polyfluoroalkyl hypochlorites, rotation of the orientation at the short bond of the addition of these strong electrophilic reagents takes place.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1572–1576, July, 1984. 相似文献
998.
Che S. Tsao 《The Journal of the Operational Research Society》1971,22(4):363-373
This paper deals with the estimation of decision parameters in a special class of inventory systems in which the rate of stock depletion depends on the internal operations of the parent organization instead of market demands. Stocking decisions for this type of inventory systems are unique in that demands for the stocked items are internal demands, sporadic in some instances, infrequent in others, and almost never the direct results of conscious economic decisions. To cope with the peculiar situation, Bayesian point and interval estimation procedures are used. The estimated probability measures provide a basis on which stocking decisions pertinent to this type of inventory systems can be made or evaluated. Specific statistical postulates are made, and a numerical example is given for illustration. The possibility of applying the estimated results to one of the existing inventory models is briefly discussed at the end. 相似文献
999.
1000.