Colloidal quantum dots (QDs) exhibit unique characteristics such as facile color tunability, pure color emission with extremely narrow bandwidths, high luminescence efficiency, and high ...photostability. In addition, quantum dot light-emitting diodes (QLEDs) feature bright electroluminescence, low turn-on voltage, and ultrathin form factor, making them a promising candidate for next-generation displays. To achieve the overarching goal of the full-color display based on the electroluminescence of QDs, however it is essential to enhance the performance of QLEDs further for each color (e.g., red, green, and blue; RGB) and develop novel techniques for patterning RGB QD pixels without cross-contamination. Here, we present state-of-the-art material, process, and device technologies for full-color QLED-based displays. First, we highlight recent advances in the development of efficient red-, green-, and blue-monochromatic QLEDs. In particular, we focus on the progress of heavy-metal-free QLEDs. Then, we describe patterning techniques for individual RGB QDs to fabricate pixelated displays. Finally, we briefly summarize applications of such QLEDs, presenting the possibility of full-color QLED-based displays.
Compared with the large plastic deformation observed in ductile metals and organic materials, inorganic semiconductors have limited plasticity (<0.2%) due to their intrinsic bonding characters, ...restricting their widespread applications in stretchable electronics. Herein, the solution‐processed synthesis of ductile α‐Ag2S thin films and fabrication of all‐inorganic, self‐powered, and stretchable memory devices, is reported. Molecular Ag2S complex solution is synthesized by chemical reduction of Ag2S powder, fabricating wafer‐scale highly crystalline Ag2S thin films. The thin films show stretchability due to the intrinsic ductility, sustaining the structural integrity at a tensile strain of 14.9%. Moreover, the fabricated Ag2S‐based resistive random access memory presents outstanding bipolar switching characteristics (Ion/Ioff ratio of ≈105, operational endurance of 100 cycles, and retention time >106 s) as well as excellent mechanical stretchability (no degradation of properties up to stretchability of 52%). Meanwhile, the device is highly durable under diverse chemical environments and temperatures from −196 to 300 °C, especially maintaining the properties for 168 h in 85% relative humidity and 85 °C. A self‐powered memory combined with motion sensors for use as a wearable healthcare monitoring system is demonstrated, offering the potential for designing high‐performance wearable electronics that are usable in daily life in a real‐world setting.
Solution‐processed synthesis of intrinsically stretchable Ag2S thin films for fabrication of self‐powered stretchable resistive memory devices is presented. The device exhibits excellent switching characteristics and mechanical stretchability (52%), and extremely high thermal and environmental durability (168 h in 85 °C/85% relative humidity). A self‐powered memory combined with motion sensors for use as a wearable healthcare monitoring system is demonstrated.
The remarkable electronic and mechanical properties of nanowires have great potential for fascinating applications; however, the difficulties of assembling ordered arrays of aligned nanowires over ...large areas prevent their integration into many practical devices. In this paper, we show that aligned VO2 nanowires form spontaneously after heating a thin V2O5 film on a grooved SiO2 surface. Nanowires grow after complete dewetting of the film, after which there is the formation of supercooled nanodroplets and subsequent Ostwald ripening and coalescence. We investigate the growth mechanism using molecular dynamics simulations of spherical Lennard–Jones particles, and the simulations help explain how the grooved surface produces aligned nanowires. Using this simple synthesis approach, we produce self-aligned, millimeter-long nanowire arrays with uniform metal–insulator transition properties; after their transfer to a polymer substrate, the nanowires act as a highly sensitive array of strain sensors with a very fast response time of several tens of milliseconds.
The antibacterial activity and acting mechanism of silver nanoparticles (SNPs) on Escherichia coli ATCC 8739 were investigated in this study by analyzing the growth, permeability, and morphology of ...the bacterial cells following treatment with SNPs. The experimental results indicated 10 μg/ml SNPs could completely inhibit the growth of 10⁷ cfu/ml E. coli cells in liquid Mueller-Hinton medium. Meanwhile, SNPs resulted in the leakage of reducing sugars and proteins and induced the respiratory chain dehydrogenases into inactive state, suggesting that SNPs were able to destroy the permeability of the bacterial membranes. When the cells of E. coli were exposed to 50 μg/ml SNPs, many pits and gaps were observed in bacterial cells by transmission electron microscopy and scanning electron microscopy, and the cell membrane was fragmentary, indicating the bacterial cells were damaged severely. After being exposed to 10 μg/ml SNPs, the membrane vesicles were dissolved and dispersed, and their membrane components became disorganized and scattered from their original ordered and close arrangement based on TEM observation. In conclusion, the combined results suggested that SNPs may damage the structure of bacterial cell membrane and depress the activity of some membranous enzymes, which cause E. coli bacteria to die eventually.
The optical gradient force provides optomechanical interactions, for particle trapping and manipulation, as well as for near-field optical imaging in scanning probe microscopy. Based on recent ...spectroscopic experiments, its extension and use for a novel form of chemical scanning probe nano-imaging was proposed. Here, we provide the theoretical basis in terms of spectral behavior, resonant enhancement, and distance dependence of the optical gradient force from numerical simulations in a coupled nanoparticle model geometry. We predict an asymmetric line shape of the optical gradient force for molecular electronic or vibrational resonances, corresponding to the real part of the dielectric function of the sample materials. Yet the line shape can become symmetric and absorptive for collective polaritonic excitations. The corresponding magnitudes of the force range from fN to pN, respectively. The distance dependence scales considerably less steeply than simple point dipole model predictions due to multipole effects. The combination of these characteristics of the optical gradient force offers the chance to experimentally distinguish it from competing processes such as thermal expansion induced forces. In addition we provide a perspective for further resonant enhancement and control of optical forces.
The spikelet number per spike (SNS) contributes greatly to grain yield in wheat. Identifying various genes that control wheat SNS is vital for yield improvement. This study used a recombinant inbred ...line population genotyped by the Wheat55K single-nucleotide polymorphism array to identify two major and stably expressed quantitative trait loci (QTLs) for SNS. One of them (QSns.sau-2SY-2D.1) was reported previously, while the other (QSns.sau-2SY-7A) was newly detected and further analyzed in this study. QSns.sau-2SY-7A had a high LOD value ranging from 4.46 to 16.00 and explained 10.21–40.78％ of the phenotypic variances. QSns.sau-2SY-7A was flanked by the markers AX-110518554 and AX-110094527 in a 4.75-cM interval on chromosome arm 7AL. The contributions and interactions of both major QTLs were further analyzed and discussed. The effect of QSns.sau-2SY-7A was successfully validated by developing a tightly linked kompetitive allele specific PCR marker in an F2:3 population and a panel of 101 high-generation breeding wheat lines. Furthermore, several genes including the previously reported WHEAT ORTHOLOG OF APO1 (WAPO1), an ortholog of the rice gene ABERRANT PANICLE ORGANIZATION 1 (APO1) related to SNS, were predicted in the interval of QSns.sau-2SY-7A. In summary, these results revealed the genetic basis of the multi-spikelet genotype of wheat line 20828 and will facilitate subsequent fine mapping and breeding utilization of the major QTLs.
Pedestrian attribute recognition (PAR) aims to recognize a series of a person's semantic attributes, e.g., age, gender, which plays an important role in video surveillance. This paper proposes a ...multi-correlation graph convolutional network named MCGCN for PAR, which includes a semantic graph, visual graph, and synthesis graph. We construct a semantic graph by using attribute features with semantic constraints. A graph convolution is employed, based on prior knowledge of the dataset, to learn the semantic correlation. 2D features are projected onto visual graph nodes and each node corresponds to the feature region of each attribute group. Graph convolution is then utilized to learn regional correlation. The visual graph nodes are connected to the semantic graph nodes to form a synthesis graph. In the synthesis graph, regional and semantic correlation are embedded into each other through inter-graph edges, to guide each other's learning and to update the visual and semantic graph, thereby constructing semantic and regional correlation. On this basis, we use a better loss weighting strategy, the suit_polyloss, to address the imbalance of pedestrian attribute datasets. Experiments on three benchmark datasets show that the proposed approach achieves superior recognition performance compared to existing technologies, and achieves state-of-the-art performance.
On the growth of Korean technoparks Link, Albert N.; Yeong Yang, U
International entrepreneurship and management journal,
06/2018, Letnik:
14, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The Republic of Korea undertook a major initiative in the early 1970s to integrate high-technology industry with its regional development strategy. This effort involved three phases: the development ...of science towns in the 1970s, the initiation of a technopolis program in the 1980s, and the establishment of science parks or technoparks in the 1990s. We focus on the third phase in this paper, and we identify empirically covariates with the employment growth of Korean technoparks. We find faster employment growth in parks established after the ICT revolution in 2000, in parks with tenants involved in more complex technology development, and in parks with more research-intensive tenants.
Grain number per spike （GNPS） is a major factor in wheat yield breeding. A new wheat germplasm Pubing 3504 shows superior features in spike traits. To elucidate the genetic basis of spike and yield ...related traits in Pubing 3504, 282 F2：3 families were generated from the cross Pubing 3504xJing 4839, and seven spike and yield related traits, including GNPS, spike length （SL）, kernel number per spikelet （KPS）, spikelet number per spike （SNS）, thousand-grain weight （TGW）, spike number per plant （SNP）, and plant height （HT） were investigated. Correlation analysis indicated significant positive correlations between GNPS and spike-related traits, including KPS, SNS, and SL, especially KPS. A genetic map was constructed using 190 polymorphic simple sequence repeat （SSR）, expressed sequence tag （EST）-SSR, and sequence- tagged-site （STS） markers. For the seven traits measured, a total of 37 quantitative trait loci （QTLs） in a single-environment analysis and 25 QTLs in a joint-environment analysis were detected. Additive effects of 70.3% （in a single environment） and 57.6% （in a joint environment） of the QTLs were positively contributed by Pubing 3504 alleles. Five important genomic regions on chromosomes 1A, 4A, 4B, 2D, and 4D could be stably detected in different environments. Among these regions, the marker interval Xmag834-Xbarc83 on the short arm of chromosome 1A was a novel important genomic region that included QTLs controlling GNPS, KPS, SNS, TGW, and SNP with stable environmental repeatability. This genomic region can improve the spike trait and may play a key role in improving wheat yield in the future. We deduced that this genomic region was vital to the high GNPS of Pubing 3504.
Diosgenin, a well-known steroid sapogenin derived from plants, has been used as a starting material for production of steroidal hormones. The present review will summarize published literature ...concerning pharmacological potential of diosgenin, and the underlying mechanisms of actions. Diosgenin has shown a vast range of pharmacological activities in preclinical studies. It exhibits anticancer, cardiovascular protective, anti-diabetes, neuroprotective, immunomodulatory, estrogenic, and skin protective effects, mainly by inducing apoptosis, suppressing malignant transformation, decreasing oxidative stress, preventing inflammatory events, promoting cellular differentiation/proliferation, and regulating T-cell immune response, etc. It interferes with cell death pathways and their regulators to induce apoptosis. Diosgenin antagonizes tumor metastasis by modulating epithelial-mesenchymal transition and actin cytoskeleton to change cellular motility, suppressing degradation of matrix barrier, and inhibiting angiogenesis. Additionally, diosgenin improves antioxidant status and inhibits lipid peroxidation. Its anti-inflammatory activity is through inhibiting production of pro-inflammatory cytokines, enzymes and adhesion molecules. Furthermore, diosgenin drives cellular growth/differentiation through the estrogen receptor (ER) cascade and transcriptional factor PPARγ. In summary, these mechanistic studies provide a basis for further development of this compound for pharmacotherapy of various diseases.
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