Performance analysis of the forward link cdma2000 1xEV‐DO evolution for multirate services in cellular wireless system

In this paper, we propose a combined analytical and simulation framework for performance evaluation of the forward link in the cdma2000 evolution for data only (1xEV‐DO) cellular systems with throughput and spectral efficiency being used as performance metrics. A closed form expression for the aggregate average throughput is derived in terms of system‐dependent parameters and a discrete random process that reflects the stochastic behavior of the transmission channel. The random process is expressed in terms of the cumulative distribution function (CDF) of the users signal‐to‐interference‐plus‐noise ratio (SINR). Quantitative results for throughput and spectral efficiency are presented for a variety of users distribution models, base station antenna types and frequency reuse factors for the cases of sectorized and non‐sectorized cells. Furthermore, we study the impact of the cell radius on the system performance. Copyright © 2006 John Wiley & Sons, Ltd.     

Influence of the density of states on the open-circuit voltage in small-molecule solar cells

Open-circuit voltages are strongly dependent on the density-of-states in solar cells based on disordered semiconductors. In this work, organic solar cells based on tetraphenyldibenzoperiflanthene and fullerene C₇₀ with a bilayer structure were fabricated to investigate the variation in the density-of-states with the substrate temperature during deposition of the donor. The maximum open circuit voltage was reached at a substrate temperature of 60 °C. Organic thin-film transistors were also fabricated to study their electrical properties, such as the mobility and the density-of-states. Finally, an organic solar cell with p–i–n structure was fabricated at the optimized substrate temperature, and a power conversion efficiency of almost 4% was obtained.     

Self‐Healing Reduced Graphene Oxide Films by Supersonic Kinetic Spraying

The industrial scale application of graphene and other functional materials in the field of electronics has been limited by inherent defects, and the lack of simple deposition methods. A simple spray deposition method is developed that uses a supersonic air jet for a commercially available reduced graphene oxide (r‐GO) suspension. The r‐GO flakes are used as received, which are pre‐annealed and pre‐hydrazine‐treated, and do not undergo any post‐treatment. A part of the considerable kinetic energy of the r‐GO flakes entrained by the supersonic jet is used in stretching the flakes upon impact with the substrate. The resulting “frozen elastic strains” heal the defects (topological defects, namely Stone‐Wales defect and C₂ vacancies) in the r‐GO flakes, which is reflected in the reduced ratio of the intensities of the D and G bands in the deposited film. The defects can also be regenerated by annealing.     

Development of transparent conducting copper and iron co-doped cadmium oxide films: Effect of annealing in hydrogen atmosphere

Hydrogenated (annealed in hydrogen atmosphere) cadmium oxide (CdO) thin films co-doped with iron (Fe) of different levels and fixed (2.5%) copper (Cu) amount were deposited on glass and silicon wafer substrates by thermal evaporation. The films were characterised with X-ray fluorescence, X-ray diffraction, optical spectroscopy, and dc-electrical measurements. The obtained results show important improvements in the conductivity, mobility, and carrier concentration compared to un-doped and non-hydrogenated CdO. Hydrogenated CdO doped with 2.5% Cu and 1.3% Fe improved the conductivity (2293.6 S/cm) by ~46 times, mobility (78.31 cm²/V s) by ~11 times, and carrier concentration (1.82×10²⁰ cm⁻³) by ~4 times. This suggests the possibility of using CdO:Cu:Fe–H as transparent-conducting-oxide and dilute-magnetic-semiconductor field of applications.     

热处理对活性层性质及有机光伏电池性能的影响

制备了MEH-PPV活性层薄膜及其器件,通过AFM、透射光谱和伏安特性测量研究了热处理对薄膜表面性质及其光电性能的影响。结果表明热处理降低了表面粗糙度,减小了禁带宽度和电阻率,提高了载流子迁移率。薄膜表面性质以及光电性能的优化,有利于增加有机光伏电池的短路电流、开路电压和填充因子,提高其能量转换效率,改善电池的器件性能。     

纳洛酮对大鼠中重度创伤性脑损伤后细胞免疫功能影响的实验研究

目的：通过观察大鼠创伤性脑损伤（traumatic brain injury,TBI）后纳洛酮治疗前后血浆β-EP、CD4＋、CD8＋和IL-2的动态变化,探讨纳洛酮对大鼠TBI后细胞免疫功能变化的影响及作用机制。方法：采用气体冲击致大鼠中重度脑损伤模型;流式细胞术、RIA、ELISA检测血液中CD4＋、CD8＋、β-EP、IL-2的变化。结果：TBI大鼠经纳洛酮治疗后,血浆中CD4＋和IL-2含量升高,β-EP和CD8＋则降低。大、小剂量纳洛酮治疗在相应时间点比较有显著性差异（P〈0.05）。结论：纳洛酮可通过降低TBI大鼠血浆中β-EP,调节TBI后应激紊乱,竞争性抑制β-EP对免疫细胞受体的作用,从而使CD4＋、CD8＋和IL-2水平趋于正常,恢复免疫平衡,起到治疗与保护作用。     

微波固体有源传感器研究

本文讨论微波固体源作为测量电量、非电量有源传感器的工作原理。指出频带反射高Q腔稳耿氏振荡器适于作为有源传感器,用它取样测量电容介质(ε_τ(?)2～3)薄膜的厚度,量程:200μm,分辨率≤±0.1μm,介质微扰稳频腔产生的振荡器频偏⊿f与其厚度d具有很好的线性关系。频偏的实验值与微扰方法计算值吻合良好。     

重叠端口通道的四、五层布线算法

本文提出了一个重叠端口通道的四、五层布线算法,算法的目标是占用尽可能少的通道布线行数,为此算法中采用了扩展布线的概念,将部分线网分配到器件区域中进行布线,在通道内部布线时,引入了重叠端口通道的垂直约束矩阵的概念,并用它来避发式算法的线网布线顺序,算法在任何情况下都能保证布线的成功,从运行实例上来看,算法速度很快,而且结果都是近似最优的（或者是最优,或者是比最优解多一个布线行）。     

Facilitation of Gene Transfection and Cell Adhesion by Gelatin‐Functionalized PCL Film Surfaces

Efficient local gene transfection on a tissue scaffold is of crucial importance in facilitating tissue repair and regeneration. In this work, the gelatin‐functionalized polycaprolactone (PCL) film surfaces are prepared via surface‐initiated atom transfer radical polymerization of glycidyl methacrylate. The resultant covalent attachment of gelatin could enhance the cell‐adhesion and local gene transfection properties. The gelatin‐functionalized PCL film surfaces exhibit excellent cell‐adhesion ability to both adherent and suspension cells. The attached adherent cells demonstrate the characteristic elongated morphologies with good spreading capability, while the attached suspension cells can maintain the original status of the round morphologies without spreading. More importantly, the gelatin coupled on the PCL surface could be used to absorb the cationic vector/plasmid deoxyribonucleic acid (pDNA) complexes via electrostatic interaction. The local gene transfection property on the immobilized cells is dependent on both the density of the immobilized cells and the loading types of pDNA complexes. The transfection efficiency of different assemble methods of pDNA complex was compared. With the pre‐ and post‐loading sandwich‐like gene transfection, the gelatin‐functionalized PCL film surface can substantially enhance the transfection properties to different cell lines. The present study is very useful to spatially control local gene delivery within PCL‐based tissue scaffolds.     

Triarylphosphine oxide–phenanthroline molecular conjugate as a promising doped electron-transport layer for organic light-emitting diodes

Over the past three decades, transparent high electron mobility molecular materials have attracted intensive research efforts for organic light-emitting diodes as electron-transport layer for the sake of low working voltage, high power efficiency and operational stability. However, developing high-performing electron-transport materials presents a demanding challenge owing to difficulties in synthesis, purification and/or processing. In this contribution, we show that n-doping a simple and facilely available phenanthroline derivative, namely 3-(6-diphenylphosphinylnaphth-2-yl)-1,10-phenanthroline Phen-NaDPO with a high T_g of 116 °C, is capable of greatly increasing the electron conductivity up to 3.3 × 10⁻⁴ S m⁻¹. The characterization of the blue sky fluorescent and green phosphorescent OLEDs involving this doped electron-transport layer Phen-NaDPO:50% wt Cs₂CO₃ revealed comparable performances to the analogue BPhen (T_g ≈ 66 °C) OLEDs. For instance, the resulting sky blue fluorescent OLEDs provided ca. 15 cd/A, 13 lm/W @1000 cd m⁻² & t₉₅ ≈ 167 h @1000 cd m⁻². The present finding shows that the doped Phen-NaDPO may be a robust electron-transport material for optoelectronics.