Heterogeneous stacking of nanodot monolayers by dry pick-and-place transfer and its applications in quantum dot light-emitting diodes

Layered assembly structures composed of nanomaterials, such as nanocrystals, have attracted considerable attention as promising candidates for new functional devices whose optical, electromagnetic and electronic behaviours are determined by the spatial arrangement of component elements. However, difficulties in handling each constituent layer in a materialspecific manner limit the 3D integration of disparate nanomaterials into the appropriate heterogeneous electronics. Here we report a pick-and-place transfer method that enables the transfer of large-area nanodot assemblies. This solvent-free transfer utilizes a lifting layer and allows for the reliable transfer of a quantum dot (QD) monolayer, enabling layer-by-layer design. With the controlled multistacking of different bandgap QD layers, we are able to probe the interlayer energy transfer among different QD monolayers. By controlling the emission spectrum through such designed monolayer stacking, we have achieved white emission with stable optoelectronic properties, the closest to pure white among the QD lightemitting diodes reported so far. (c) 2013 Macmillan Publishers Limited. All rights reserved.402

A study on Korean secondary school English teachers' beliefs and practices about English writing education in South Korea

Master of EducationThis thesis investigates the relationship between Korean secondary school English teachers' beliefs about and practices in English writing education and the factors that affect this relationship. By identifying the significant factors that influence the consistencies and the inconsistencies between teachers' beliefs and practices, this study attempts to advance English writing education in South Korea. In a number of subject area, teachers' beliefs, as one facet of teacher cognition, have been a major focus in studies of teaching to better understand teachers' classroom practices and to improve teacher education. However, the subject of teacher beliefs on second language writing has attracted relatively little attention from researchers. In addition, few studies have been conducted in a Koreanspecific context. This study therefore attempts to contribute to the literature on teacher cognition in relation to a Korean-specific context. Adopting an interpretive perspective, this study employed a qualitative multi-case study method to study Korean secondary teachers' beliefs about and practices of how to teach writing. Drawing on data that included teaching materials, literacy autobiographies, and semi-structured interviews with six Korean secondary school English teachers, the results of this study showed that generally teachers' beliefs about English writing education are consistent with their practices. However, some beliefs were not so strongly reflected in the teachers' classroom practices. The reasons for the weak consistencies between some beliefs and teachers' practices were related to issues of educational policy and teachers' professional development. Korean educational policy relating to English education, such as textbooks, the Korean College Scholastic Aptitude Test, large class sizes, was one factor that hinders teachers from actualizing their beliefs. Another significant factor identified in this study concerned teacher factors, including teachers' lack of confidence in giving English writing instruction. This research concludes with some implications in these two areas for further improvement of English writing education in South Korea

Evaluation of Nitrogen Oxide Reduction Performance in Permeable Concrete Surfaces Treated with a TiO₂ Photocatalyst

Fine dust, recently classified as a carcinogen, has raised concerns about the health effects of air pollution. Vehicle emissions, particularly nitrogen oxide (NOx), contribute to ultrafine dust formation as a fine dust precursor. A photocatalyst, such as titanium dioxide (TiO2), is a material that causes a catalytic reaction when exposed to light, has exceptional characteristics such as decomposition of pollutants, and can be used permanently. This study aimed to investigate NOx reduction performance by developing ecofriendly permeable concrete with photocatalytic treatment to reduce fine dust generated from road mobile pollution sources. Permeable concrete specimens containing an activated loess and zeolite admixture were prepared and subjected to mechanical and durability tests. All specimens, including the control (CTRL) and admixture, met quality standard SPS-F-KSPIC-001-2006 for road pavement. Slip resistance and permeability coefficient also satisfied the standards, while freeze–thaw evaluation criteria were met only by CTRL and A1Z1 specimens. NOx reduction performance of the permeable concrete treated with TiO2 photocatalyst was assessed using ISO standard and tank chambers. NOx reduction efficiency of up to 77.5% was confirmed in the permeable concrete specimen with TiO2 content of 7.5%. Nitrate concentration measurements indirectly confirmed photolysis of nitrogen oxide. Incorporating TiO2 in construction materials such as roads and sidewalks can improve the atmospheric environment for pedestrians near roads by reducing NOx levels through photocatalysis

Redistributive Effect of U.S. Taxes and Public Transfers, 1994-2004

30 p.In this study we derive measures of the redistributive effect of taxes and welfare expenditures for the U.S. using CPS data for the years 1994, 1999 and 2004. We find that whilst income inequality increased, the redistributive effect of taxes and public transfers together reduced market income inequality by approximately 30 percent. In 2004, 88 percent of the net redistributive effect resulted from public transfers and 12 percent from taxes. The total redistributive effect would have improved by 35 percent in 2004 if, all else equal, horizontal inequities in taxes and public transfers could have been eliminated

Release of hydrophobic molecules from polymer micelles into cell membranes revealed by Forster resonance energy transfer imaging

it is generally assumed that polymeric micelles, upon administration into the blood stream, carry drug molecules until they are taken up into cells followed by intracellular release. The current work revisits this conventional wisdom. The study using dual-labeled micelles containing fluorescently labeled copolymers and hydrophobic fluorescent probes entrapped in the polymeric micelle core showed that cellular uptake of hydrophobic probes was much faster than that of labeled copolymers. This result implies that the hydrophobic probes in the core are released from micelles in the extracellular space. Forster resonance energy transfer (FRET) imaging and spectroscopy were used to monitor this process in real time. A FRET pair, DiIC(18(3)) and DiOC(18(3)), was loaded into monomethoxy poly(ethylene glycol)-block-poly(D,L-lactic acid) micelles. By monitoring the FRET efficiency, release of the core-loaded probes to model membranes was demonstrated. During administration of polymeric micelles to tumor cells, a decrease of FRET was observed both on the cell membrane and inside of cells, indicating the release of core-loaded probes to the cell membrane before internalization. The decrease of FRET on the plasma membrane was also observed during administration of paclitaxel-loaded micelles. Taken together, our results suggest a membrane-mediated pathway for cellular uptake of hydrophobic molecules preloaded in polymeric micelles. The plasma membrane provides a temporal residence for micelle-released hydrophobic molecules before their delivery to target intracellular destinations. A putative role of the PEG shell in the molecular transport from micelle to membrane is discussed

Sentiment-Target Word Pair Extraction Model Using Statistical Analysis of Sentence Structures

Product information has been propagated online via forums and social media. Lots of merchandise are recommended via an expert system method and is considered for purchase by online comments or product reviews. For predicting people’s opinions on products, studying people’s thoughts via extracting information in documents is referred to as sentiment analysis. Finding sentiment-target word pairs is an important sentiment mining research issue. With the Korean language, as the predicate appears at the very end, it is not easy to find the exact word pairs without first identifying the syntactic structure of the sentence. In this study, we propose a model that parses sentence structures and extracts sentiment-target word pairs from the parse tree. The proposed model extracts the sentiment-target word pairs that appear in the sentence by using parsing and statistical methods. For extracting sentiment-target word pairs, this model uses a sentiment word extractor and a target word extractor. After testing data from 4000 movie reviews, the applicable model showed high performance in both accuracy 93.25 (+14.45) and F1-score 82.29 (+3.31) compared with others. However, improvements in the recall rate (−0.35) are needed and computational costs must be reduced