ALBERT

Notes: RF (Resorcinol-Formaldehyde) aerogels and carbon aerogels were prepared through thesol-gel method following the routes of polymerization, gelation, supercritical drying and pyrolysisprocesses. The influence of fabrication parameters on the textural structure of the samples, e.g.,specific surface area, pore size, and pore size distribution, etc., were systematically investigated. Witha decrease in the R/F molar ratio, or an increase in the catalyst content within a limited range, theporosity of the nanostructure materials increases. The optimal temperature of pyrolysis for RF aerogelwas investigated by TGA (Thermogravimetric Analysis)

Notes: Transparent indium-doped ZnO (IZO) films with low In content (〈6at%) were fabricatedthrough radio-frequency (rf) helicon magnetron sputtering. Formation of In-Zn-O solid solution wasconfirmed by X-ray diffraction (XRD) patterns. Incorporation of indium into ZnO films enhances theoptical transmission in the visible wavelength. The optical band-gaps slightly increase from 3.25eV(ZnO) to 3.28eV (In0.04Zn0.96O) and to 3.30eV (In0.06Zn0.94O) due to Burstain-Moss effect. TheUrbach tail parameter E0, which is believed to be a function of structural disorder, increases from79meV (ZnO), to 146meV (In0.04Zn0.96O), and to 173meV (In0.06Zn0.94O), which is consistent withincrease of Full-Width Half-Maximum (FWHM) in corresponding XRD patterns. Decreasing incrystal quality with increasing indium concentration is also confirmed by photoluminescence spectra

Notes: Biodegradable composites made from bagasse fiber and biodegradable resin were preparedand the biodegradation were investigated by the soil burial test in terms of the effects of fiber content,alkali treatment to bagasse fiber and different soil. The biodegradable resin showed some extentbiodegradation. The addition of bagasse fiber caused the acceleration of weight loss of the fiberreinforced composites in comparison with the neat biodegradable resin. The weight loss of thecomposites increased with the increase in the fiber content, which could attribute to the preferentialdegradation of bagasse fiber and the resin around the fiber. However there was no significantdifference in weight loss between untreated and alkali treated fiber composites. Furthermore, it isnoted that the weight loss drastically increased in the case of the composites buried in themicroorganism enriched soil. This results from the increase of bacteria and fungi in soil. Thephotographs and SEM micrographs showed the degradation of the resin and the composites

Notes: As a “bottom-up” approach to nanostructures for nanofabrication, self-assembled blockcopolymer thin films have received much attention not only thanks to the scale of the microdomainsbut also due to the convenient shape tunability. In order to realize applications of self-assembledblock copolymer thin films in nanotechnologies, control over microdomain spatial and orientationalorder is paramount. In this paper, using atomic force microscopy (AFM), we studied systemicallynanostructure transitions induced by post-solvent annealing in self-assembled block copolymer thinfilms. Furthermore, a variety of thin films with well-ordered nanostructures, which can be employedas templates for nanotechnologies, have been realized simply and at low cost

Notes: Polymer light-emitting diodes based on copolyfluorene with barium/aluminum cathode were thermally annealed at different temperatures through different time periods. It was found that by annealing just below the glass transition temperature (sub-Tg) of these copolymers the device performance was greatly enhanced. Lower turn-on voltage, higher maximum brightness, and more than two times higher external electroluminescent (EL) quantum efficiency could be achieved in this way. We found out that the enhancement in electron injection and the increase in carrier mobility after thermal annealing at a temperature close to Tg of the EL polymers are responsible for the improvement in device performance. © 2002 American Institute of Physics.

Notes: Measurements of the frequency dependence of the complex admittance are used to separate the ionic and electronic contributions in polymer light-emitting electrochemical cells (LECs). At zero bias, a large polarizability, attributed to salt molecules in the electrolyte, is observed at low frequencies. Ions are generated when the LEC is biased at voltages above the threshold for electrochemical redox doping. Because of the slow ionic response, a novel pulsed drive scheme is proposed: the mean value stabilizes the induced p-i-n junction, while the peak value controls the carrier injection and the brightness of the electroluminescent emission. LECs operated in this way exhibit fast emissive response and improved operating life. © 1998 American Institute of Physics.

Notes: 1. Numerous methods have been developed to sample the biota occurring in different ecosystems. However, the comparability of data derived from different sampling methods is generally unknown and is a major concern when integrating data from different studies.2. Examination of assemblage-level attributes such as taxa richness and biotic index scores is generally inappropriate for evaluating the degree to which different sampling methods produce comparable descriptions of entire assemblages, because these measures provide no information regarding taxonomic composition. Multivariate methods are generally more appropriate for this purpose, but some of the methods previously used are not satisfactory and others have not been tested. A useful measure of sampling-method comparability (SMC) should be independent of sampling effort, independent of the sites sampled and have an explicit biological interpretation.3. We used simulated data to compare two potential methods of assessing SMC, the R-value produced by anosim and a modified version of classification strength (CS-SMC) derived from Van Sickle's Mean Similarity Analysis. Analyses were based on similarities between the assemblages captured by two different sampling methods (electrofishing and seining) employed at the same sites. Similarities were calculated two different ways: the Bray–Curtis index and the Jaccard coefficient.4. Based on simulated data, anosimR-values were strongly affected by sampling effort, highly variable across sites and difficult to interpret biologically. In contrast, CS-SMC values were highly stable over a range of sampling effort, across sites and easy to interpret biologically.5. Application of CS-SMC to field data showed that seining and electrofishing produced highly comparable samples of fish in small streams: 97% comparable on average for species lists and 94% comparable for relative abundances. Kicknet and Surber samples of benthic invertebrates were also comparable after being standardised to a fixed count, but to a lesser extent than fish samples: 77% comparable on average for the taxa lists and 93% comparable for relative abundances. CS-SMC should be of general use when integrating and synthesising assemblage data from a variety of assemblages.

Notes: 1. Biological assemblage surveys primarily aim to characterise species composition and relative abundance at one or more spatial or temporal scales. Data interpretation and conclusions are dependent on how well samples characterise the assemblage of interest.2. Conventional measures of data quality, e.g. standard deviations or coefficients of variation, were designed for single variable estimation, and they are either insufficient or invalid for assessing the quality of data describing entire assemblages. Similarity indices take species composition and relative abundance into account and may be used to effectively measure and control the quality of data used to characterise assemblage structure.3. The average Jaccard coefficient (JC) calculated across multiple pairs of replicate samples, i.e. autosimilarity JC (AJC), is conceptually and numerically related to the average coefficient of variation in the densities of all species recorded, a measure of sampling precision, and to the proportion of total species richness sampled, a measure of sampling accuracy.4. We explored how AJC can be used to assess the effect of different potential sources of error on the quality of assemblage survey data, including the sampling effort used both within regions and at individual sites, the individuals collecting samples, sub-sampling procedures, and consistency of taxon identification.5. We found that the autosimilarity-based approach overcomes most weaknesses associated with conventional measures of data quality and can be used to effectively measure and control the quality of assemblage survey data.

Notes: Polymer light emitting diodes in which the cathode comprises an ultrathin layer of alkaline earth metal show much better operating lifetime, especially at high temperatures, in comparison with devices fabricated with cathodes from the same metals with thickness greater than 100 Å. The operating lifetime is dependent on the specific low work function metal used. Among the alkali and alkaline earth metals, devices with ∼30 Å Ba as cathode show the best half life during continuous operation. Using an ultrathin Ba cathode with an Al or Ag capping layer and poly[2-(3,7-dimethyloctyloxy)-5-methoxy-1,4-phenylenevinylene] as luminescent polymer, the half life reaches 400 h at 85 °C and exceeds 10 000 h at room temperature when operated at a current density of 8.3 mA/cm2 with a luminance of 100–140 cd/cm2. © 2000 American Institute of Physics.

Notes: Iridium complexes with alkyl substituted 2-phenylpyridine, Ir(Bu-PPy)3, were synthesized. Polymer light emitting diodes with Ir complexes as the guest materials and the substituted polyphenylenes as the host were fabricated. Ir(Bu-PPy)3-doped Poly(2-(6-cyano-6-methyl)- heptyloxy-1,4-phenylene) (CNPPP) device showed generally higher quantum efficiency (QE) than that of Ir(PPy)3-doped device for a given dopant concentration. More importantly, the addition of butyl group into phenylpyridine ligand significantly suppresses the decay of device efficiency at high current density. For instance, for devices made with Ir(Bu-PPy)3-doped CNPPP: the maximum external quantum efficiency, QE, and luminance efficiency reached 5.1% ph/el and 12 cd/A, respectively, at 800 cd/m2 and maintained at 4.2% ph/el and 10 cd/A, respectively, at 2500 cd/m2. © 2002 American Institute of Physics.