Organic Nanoparticles: Preparation,Self‐Assembly,and Properties

The strong tendency of organic nanoparticles to rapidly self‐assemble into highly aligned superlattices at room temperature when solution‐cast from dispersions or spray‐coated directly onto various substrates is described. The nanoparticle dispersions are stable for years. The novel precipitation process used is believed to result in molecular distances and alignments in the nanoparticles that are not normally possible. Functional organic light‐emitting diodes (OLEDs)—which have the same host–dopant emissive‐material composition—with process‐tunable electroluminescence have been built with these nanoparticles, indicating the presence of novel nanostructures. For example, only changing the conditions of the precipitation process changes the OLED emission from green light to yellow.     

Extracting Light from Polymer Light‐Emitting Diodes Using Stamped Bragg Gratings

In this paper, we describe a method for increasing the external efficiency of polymer light‐emitting diodes (LEDs) by coupling out waveguided light with Bragg gratings. We numerically model the waveguide modes in a typical LED structure and demonstrate how optimizing layer thicknesses and reducing waveguide absorption can enhance the grating outcoupling. The gratings were created by a soft‐lithography technique that minimizes changes to the conventional LED structure. Using one‐dimensional and two‐dimensional gratings, we were able to increase the forward‐directed emission by 47 % and 70 %, respectively, and the external quantum efficiency by 15 % and 25 %.     

Platinum Binuclear Complexes as Phosphorescent Dopants for Monochromatic and White Organic Light‐Emitting Diodes

Efficient blue‐, green‐, and red‐light‐emitting organic diodes are fabricated using binuclear platinum complexes as phosphorescent dopants. The series of complexes used here have pyrazolate bridging ligands and the general formula C^∧NPt(μ‐pz)₂PtC^∧N (where C^∧N = 2‐(4′,6′‐difluorophenyl)pyridinato‐N,C^2′, pz = pyrazole ( 1 ), 3‐methyl‐5‐tert‐butylpyrazole ( 2 ), and 3,5‐bis(tert‐butyl)pyrazole ( 3 )). The Pt–Pt distance in the complexes, which decreases in the order 1 > 2 > 3 , solely determines the electroluminescence color of the organic light‐emitting diodes (OLEDs). Blue OLEDs fabricated using 8 % 1 doped into a 3,5‐bis(N‐carbazolyl)benzene (mCP) host have a quantum efficiency of 4.3 % at 120 Cd m^–2, a brightness of 3900 Cd m^–2 at 12 V, and Commission Internationale de L'Eclairage (CIE) coordinates of (0.11, 0.24). Green and red OLEDs fabricated with 2 and 3 , respectively, also give high quantum efficiencies (～ 6.7 %), with CIE coordinates of (0.31, 0.63) and (0.59, 0.46), respectively. The current‐density–voltage characteristics of devices made using dopants 2 and 3 indicate that hole trapping is enhanced by short Pt–Pt distances (< 3.1 Å). Blue electrophosphorescence is achieved by taking advantage of the binuclear molecular geometry in order to suppress dopant intermolecular interactions. No evidence of low‐energy emission from aggregate states is observed in OLEDs made with 50 % 1 doped into mCP. OLEDs made using 100 % 1 as an emissive layer display red luminescence, which is believed to originate from distorted complexes with compressed Pt–Pt separations located in defect sites within the neat film. White OLEDs are fabricated using 1 and 3 in three different device architectures, either with one or two dopants in dual emissive layers or both dopants in a single emissive layer. All the white OLEDs have high quantum efficiency (～ 5 %) and brightness (～ 600 Cd m^–2 at 10 V).     

An evaluation of biological and abiotic controls for grapevine powdery mildew. 2. Vineyard trials

Grapevine powdery mildew ( Erysiphe necator) affects grape yield and fruit quality worldwide. Managers of conventional vineyards rely mainly on synthetic fungicides and sulfur to control powdery mildew, while in organic vineyards sulfur is the main control agent, often in rotation with canola-based oils, bicarbonates and biological control agents. The efficacy of those materials has not been evaluated critically under field conditions in Australia. Accordingly, a range of materials showing most promise in previous greenhouse trials (Crisp et al. 2006 Australian Journal of Grape and Wine Research 12 , pp. 192–202) were assessed via field trials in commercial vineyards. Applications of either milk or whey (alone, or mixed with a canola oil-based product), as well as applications of potassium bicarbonate (commercial formulation), all reduced the severity of powdery mildew compared with untreated vines. Eight applications of a 1:10 dilution of milk, 45 g/L whey powder or programs comprising rotations of potassium bicarbonate plus oil and whey, applied at 10–14 day intervals, reduced the severity of powdery mildew to levels not significantly different from that on vines sprayed with sulfur (wettable powder, 3–6 g/L). However, the relative control of powdery mildew by the test materials in field trials was dependent on the susceptibility of the grapevine cultivar and the extent of spray coverage achieved. In vineyards where highly susceptible cultivars were planted, and spray coverage was compromised, the resultant control of powdery mildew was reduced; and sometimes to commercially unacceptable levels.     

深孔钻机水刹车传动机构的设计改进

针对深孔钻机水刹车传动机构原设计结构中存在的问题进行分析、研究、并对机构进行了改进，满足了钻机绞车的各项性能指标和技术要求。     

医用聚氯乙烯材料的表面光接枝改性

研究了在不排氧氛围下 ,紫外光照射 ,以二苯甲酮 (BP)为光引发剂 ,甲基丙烯酸缩水甘油酯(GMA)在医用聚氯乙烯 (PVC)薄膜表面的气相接枝聚合。探讨了反应条件对接枝结果的影响 ,并用正交法指出了影响因素的显著性。用傅立叶红外 (FT- IR)、水接触角作为接枝改性结果的表征。FT- IR谱图表明 GMA已接枝到 PVC膜表面。水接触角由接枝前的 78°下降到 5 4°     

Inhibition of acid rock drainage from uranium ore waste using a conventional neutralization and precipitation treatment

Glass columns (length 50 cm, i.d. 4 cm) containing 900 g of uranium ore waste were subjected to a three-step process: (1) acid drainage generation, (2) neutralization and precipitation treatment and, again, (3) acid drainage generation. In the first acid generation step, lasting about one year, different variables (pyrite addition, inoculation and irrigation solution) were tested by measuring effluent pH, redox potential, total iron and sulphate. Conditions of acid generation were satisfactorily reproduced, reaching stable pH values around 2.0 that were determined mainly by pyrite addition and the type of irrigation solution used (distilled water or ferrous sulphate). The neutralization and precipitation treatment consisted of alternating irrigations of a neutralizing solution (CaO saturated plus NaOH) and a precipitating solution (ferric sulphate saturated). This treatment caused accumulation of basic iron sulphate and iron oxide precipitates according to SEM studies. After this treatment, the barrier effect created by the reaction products was checked, using irrigation solutions similar to the first step. The effluents collected showed higher pH and lower redox potential, total iron and sulphate values than those observed before the treatment, evidencing inhibition of acid drainage generation.     

旋风分离器结构改进的研究

根据旋风分离器的工作原理及应用特点 ,分析了影响旋风分离器分离效率的因素及结构存在的问题 ,并提出了改进措施 ,即内管外壁增设螺旋翼片 ,扩散形锥体改为悬挂挡板。通过实验观察 ,改进结构的旋风分离器分离效率比常规旋风分离器高。实践证明 ,对于密度差异较小的非均相物系的分离 ,只要对旋风分离器作适当改进 ,仍能取得令人满意的效果 ,这大大拓宽了旋风分离器的应用领域     

锂离子电池有机电解液成膜添加剂的研究现状

文章综述了锂离子电池有机电解液成膜添加剂的作用原理，具体介绍了CO2、SO2、VC化合物、卤化物、有机铜盐以及马来酐等添加剂的研究现状。