Randomly Disassembled Nanostructure for Wide Angle Light Extraction of Top-Emitting Quantum Dot Light-Emitting Diodes.

The quantum dot light-emitting diode (QLED) represents one of the strongest display technologies and has unique advantages like a shallow emission spectrum and superior performance based on the cumulative studies of state-of-the-art quantum dot (QD) synthesis and interfacial engineering. However, research on managing the device's light extraction has been lacking compared to the conventional LED field. Moreover, relevant studies on top-emitting QLEDs (TE-QLEDs) have been severely lacking compared to bottom-emitting QLEDs (BE-QLEDs). This paper demonstrates a novel light extraction structure called the randomly disassembled nanostructure (RaDiNa). The RaDiNa is formed by detaching polydimethylsiloxane (PDMS) film from a ZnO nanorod (ZnO NR) layer and laying it on top of the TE-QLED. The RaDiNa-attached TE-QLED shows significantly widened angular-dependent electroluminescence (EL) intensities over the pristine TE-QLED, confirming the effective light extraction capability of the RaDiNa layer. Consequently, the optimized RaDiNa-attached TE-QLED achieves enhanced external quantum efficiency (EQE) over the reference device by 60%. For systematic analyses, current-voltage-luminance (J-V-L) characteristics are investigated using scanning electron microscopy (SEM) and optical simulation based on COMSOL Multiphysics. It is believed that this study's results provide essential information for the commercialization of TE-QLEDs.

Analysis of design-for-safety implementation factors in the Indonesian construction industry: A two-staged SEM-artificial neural network approach.

Despite the rapid growth of infrastructure development in Indonesia, work safety remains a major concern in construction projects. Design-for-safety (DfS) is a critical strategy to prevent work accidents. The implementation of design-for-safety is one of the most important strategies for preventing work accidents. This study aimed to analyze multiple factors that influence the implementation of work safety design using two statistical approaches: structural equation modeling and an artificial neural network. Structural equation modeling analyzes the relationship pattern between variables and their indicators, and artificial neural network maps various similar patterns to predict variables that influence implementation. Designers, owners, policies, tools/equipment, knowledge, and contract documents positively affect design-for-safety implementation, with design and contract documents being the most significant variables. Accordingly, industry and government agencies are advised to prioritize contract documents and design factors, along with other variables as supporting factors in their programs to accelerate design-for-safety implementation in Indonesia.

Correlation analysis of safety climate and construction productivity in South Korea.

Purpose. The purpose of this study is to analyze the correlation between safety climate and productivity for actual construction projects. The safety climate of the case projects was analyzed using the Nordic occupational safety climate questionnaire for the participants of the projects, and the resources used for the main work were used to analyze productivity. Methods. Many researchers have concluded that if the safety climate in a construction business improves, the rate of human accidents decreases. A decrease in accidents or injuries means that the quality of labor is improved; productivity can be expected to increase as a result. However, some site engineers argue that there is a dilemma since management costs increase when the safety climate is improved. If quantitative analysis of the correlation between safety climate and construction productivity can be performed, the results may show that additional costs to improve the safety climate are offset by productivity gains. Conclusions. As a result of regression analysis, we concluded that there is a significant relationship between safety climate and productivity. In the future, our findings can be used as a reference for developing a construction productivity prediction model as influenced by the safety climate.

Worker safety perception analysis of South Korean construction sites.

Purpose. The aim of this article was to measure the safety perception level of workers on a South Korean construction site and investigate safety problems using the Nordic occupational safety climate questionnaire (NOSACQ-50). Methods. The survey was carried out via the NOSACQ-50 with 175 workers from five South Korean construction companies to evaluate their perception level. The results were then compared with the NOSACQ-50 criteria. Results. The safety perception of this South Korean construction site is high when compared with the NOSACQ-50 criteria. This high level was especially pronounced for the seventh dimension of the efficacy of the safety system, which showed the highest level among all dimensions. In addition, we suggested improvements and interventions to sustain a safety climate amongst workgroups. Conclusions. This study confirms that the seventh dimension showed the highest safety perception amongst all dimensions in South Korea. In the future, these findings can be utilized to develop an evaluation tool for the safety climate of the construction industry in South Korea.

Soil pH and electrical conductivity are key edaphic factors shaping bacterial communities of greenhouse soils in Korea.

Soil microorganisms play an essential role in soil ecosystem processes such as organic matter decomposition, nutrient cycling, and plant nutrient availability. The land use for greenhouse cultivation has been increasing continuously, which involves an intensive input of agricultural materials to enhance productivity; however, relatively little is known about bacterial communities in greenhouse soils. To assess the effects of environmental factors on the soil bacterial diversity and community composition, a total of 187 greenhouse soil samples collected across Korea were subjected to bacterial 16S rRNA gene pyrosequencing analysis. A total of 11,865 operational taxonomic units at a 97% similarity cutoff level were detected from 847,560 sequences. Among nine soil factors evaluated; pH, electrical conductivity (EC), exchangeable cations (Ca2+, Mg2+, Na+, and K+), available P2O5, organic matter, and NO3-N, soil pH was most strongly correlated with bacterial richness (polynomial regression, pH: R2 = 0.1683, P < 0.001) and diversity (pH: R2 = 0.1765, P < 0.001). Community dissimilarities (Bray-Curtis distance) were positively correlated with Euclidean distance for pH and EC (Mantel test, pH: r = 0.2672, P < 0.001; EC: r = 0.1473, P < 0.001). Among dominant phyla (> 1%), the relative abundances of Proteobacteria, Gemmatimonadetes, Acidobacteria, Bacteroidetes, Chloroflexi, and Planctomycetes were also more strongly correlated with pH and EC values, compared with other soil cation contents, such as Ca2+, Mg2+, Na+, and K+. Our results suggest that, despite the heterogeneity of various environmental variables, the bacterial communities of the intensively cultivated greenhouse soils were particularly influenced by soil pH and EC. These findings therefore shed light on the soil microbial ecology of greenhouse cultivation, which should be helpful for devising effective management strategies to enhance soil microbial diversity and improving crop productivity.