Textured Antireflection Sticker Film for Efficient Solar Cells

Department of Energy EngineeringFor highly efficient solar cell, it is necessary to understand all the light loss in the solar cell and develop broadband light harvesting. This thesis reports a polydimethylsiloxane (PDMS) film composed of random sized inverted pyramidal structure (RSIPS) fabricated by simple and cheap process that displays excellent optical properties. The RSIPS-PDMS film shows high optical haze which increase the light scattering and low reflection because of a linear grading of the effective refractive index profile from the air to glass or silicon layer. By applying the RSIPS-PDMS on Si solar cell, the current density and efficiency was improved (i.e., 35.9mA/cm^2, 16%) compared to those of reference device (i.e., 33.1mA/cm^2, 14.9%). Also, a polymer solar cell (PSC) with RSIPS-PDMS film has improved current density and efficiency. The RSIPS-PDMS film is suitable for an antireflection film of diverse solar cells.ope

Influence of Xanthan gum biopolymer-based Soil Treatment on Particle Level Inter-Binding and Shear Behaviour of Soils

With the growing demand for sustainable construction materials, microbial biopolymers have been recently introduced in geotechnical engineering. Indeed, many researchers have conducted relevant studies to investigate the effects of biopolymer treatment on soils. The various types of biopolymers have shown their competitiveness compared to conventional binders such as cement. In this study, xanthan gum biopolymer was chosen because of workability and economic feasibility. From the understanding of rheological properties, applicability of xanthan gum on Tunnel Boring Machine (TBM) slurry additive was suggested in accordance with the shear thinning characteristics of xanthan gum. As a parallel section, the soil strengthening effect in terms of erosion behaviour and shear behaviour was assessed through the experimental program. Indeed, biopolymer treatment with less than 2.0% in mass ratio was effective on soil strengthening effects, resulting in erosion resistance and shear resistance improvement. In addition, this study aims to achieve a better understanding of xanthan gum biopolymer film matrix formation in soils in the manner of quantitative analysis. The biopolymer film matrix formation pattern was quantitatively analysed using a laboratory microscopic observation test. The newly introduced parameters (i.e., degree of biopolymer filling, dehydrated biopolymer concentration, connectivity) from the microscopic observation test were assessed, and those parameters were correlated with the erosion parameter and the shear parameters from the laboratory assessment. Porosity was applied as a main variable for the analysis of each correlation. While the porosity was an influential factor, different soil packing conditions (i.e., simple cubic soil packing and rhombohedral soil packing) showed the effect of pore size between sand particles on xanthan gum biopolymer film matrix. For another feasible application, the feasibility of xanthan gum on road shoulder pavement was basically assessed in the laboratory. While it remains difficult to simulate practical ground conditions to develop a highly reliable relationship between engineering properties and parameters for the biopolymer film matrix formation pattern, this research would be worthwhile to initiate an attempt for quantitative analysis of xanthan gum biopolymer film matrix formation

Laying the Foundation for Crassulacean Acid Metabolism (CAM) Biodesign: Expression of the C4 Metabolism Cycle Genes of CAM in Arabidopsis

Crassulacean acid metabolism (CAM) is a specialized mode of photosynthesis that exploits a temporal CO2 pump with nocturnal CO2 uptake and concentration to reduce photorespiration, improve water-use efficiency (WUE), and optimize the adaptability of plants to hotter and drier climates. Introducing the CAM photosynthetic machinery into C3 (or C4) photosynthesis plants (CAM Biodesign) represents a potentially breakthrough strategy for improving WUE while maintaining high productivity. To optimize the success of CAM Biodesign approaches, the functional analysis of individual C4 metabolism cycle genes is necessary to identify the essential genes for robust CAM pathway introduction. Here, we isolated and analyzed the subcellular localizations of 13 enzymes and regulatory proteins of the C4 metabolism cycle of CAM from the common ice plant in stably transformed Arabidopsis thaliana. Six components of the carboxylation module were analyzed including beta-carbonic anhydrase (McBCA2), phosphoenolpyruvate carboxylase (McPEPC1), phosphoenolpyruvate carboxylase kinase (McPPCK1), NAD-dependent malate dehydrogenase (McNAD-MDH1, McNAD-MDH2), and NADP-dependent malate dehydrogenase (McNADP-MDH1). In addition, seven components of the decarboxylation module were analyzed including NAD-dependent malic enzyme (McNAD-ME1, McNAD-ME2), NADP-dependent malic enzyme (McNADP-ME1, NADP-ME2), pyruvate, orthophosphate dikinase (McPPDK), pyruvate, orthophosphate dikinase-regulatory protein (McPPDK-RP), and phosphoenolpyruvate carboxykinase (McPEPCK). Ectopic overexpression of most C4-metabolism cycle components resulted in increased rosette diameter, leaf area, and leaf fresh weight of A. thaliana except for McNADP-MDH1, McPPDK-RP, and McPEPCK. Overexpression of most carboxylation module components resulted in increased stomatal conductance and dawn/dusk titratable acidity (TA) as an indirect measure of organic acid (mainly malate) accumulation in A. thaliana. In contrast, overexpression of the decarboxylating malic enzymes reduced stomatal conductance and TA. This comprehensive study provides fundamental insights into the relative functional contributions of each of the individual components of the core C4-metabolism cycle of CAM and represents a critical first step in laying the foundation for CAM Biodesign

Customized Energy Down-Shift using Iridium Complexes for Enhanced Performance of Polymer Solar Cells

School of Molecular Sciences(Chemistry)For the higher performance of polymer solar cells (PSCs), many researchers tried to develop new polymers that can absorb broader range of spectrum. However, there are some limits to absorb broader range with single donor. Therefore, multi donor systems and energy transfer systems have been researched. With two different donors it is easier to enhance absorption range. As a result, multi donor and energy transfer was successful to increase performance. However, the existing systems are applying polymer-polymer systems. When two different polymers are mixed, the compatibility between two polymers is critical to morphology of blend film. Also, in polymer-polymer energy transfer, the boundary between charge transfer and energy transfer is unclear. Therefore, for the first time, we developed customized iridium (Ir(III)) complexes, with Ir(III) complex incorporated into the active materials poly(thieno[3,4-b]-thiophene/benzodithiophene) (PTB7, amorphous) or poly(3-hexylthiophene) (P3HT, high crystalline) as energy donor additives. The Ir(III) complex with the 2-phenyl quinolone ligand energy donor increased the power conversion efficiency of the corresponding devices by approximately 20%. The enhancements are attributed to the improved molecular compatibility and energy level between the Ir(III) complex and the active materials, long F??rster resonance energy transfer radius, and high energy down-shift efficiency. Overall, we reveal Ir(III) complex additives for amorphous and highly crystalline polymer active materialsthese additives would enable efficient energy transfer in polymer solar cells, while retaining the desirable active layer morphology, thereby resulting in improved light absorption and conversion.ope

Comprehensive identification of sexually dimorphic genes in diverse cattle tissues using RNA-seq

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background Molecular mechanisms associated with sexual dimorphism in cattle have not been well elucidated. Furthermore, as recent studies have implied that gene expression patterns are highly tissue specific, it is essential to investigate gene expression in a variety of tissues using RNA-seq. Here, we employed and compared two statistical methods, a simple two group test and Analysis of deviance (ANODEV), in order to investigate bovine sexually dimorphic genes in 40 RNA-seq samples distributed across two factors: sex and tissue. Results As a result, we detected 752 sexually dimorphic genes across tissues from two statistical approaches and identified strong tissue-specific patterns of gene expression. Additionally, significantly detected sex-related genes shared between two mammal species (cattle and rat) were identified using qRT-PCR. Conclusions Results of our analyses reveal that sexual dimorphism of metabolic tissues and pituitary gland in cattle involves various biological processes. Several differentially expressed genes between sexes in cattle and rat species are shared, but show tissue-specific patterns. Finally, we concluded that two distinct statistical approaches have their advantages and disadvantages in RNA-seq studies investigating multiple tissues