Quantum dot light-emitting diodes are promising light sources for applications in displays. However, to date, there have been no reports of devices that simultaneously offer both high brightness and ...high external quantum efficiency. Here, we report red, green and blue quantum dot light-emitting diodes based on CdSe/ZnSe core/shell structures that have these attributes. We demonstrate devices with maximum external quantum efficiencies of 21.6%, 22.9% and 8.05% for red, green and blue colours with corresponding brightness of 13,300 cd m–2, 52,500 cd m–2 and 10,100 cd m–2. The devices also offer peak luminance of 356,000 cd m–2, 614,000 cd m–2 and 62,600 cd m–2, respectively. We postulate that this high performance is due to the use of Se throughout the core/shell regions and the existence of alloyed bridging layers at the core/shell interfaces. This study suggests that in the future visible quantum dot light-emitting diodes will also be suitable for lighting applications.Red, green and blue CdSe/ZnSe quantum dot light-emitting diodes combine efficient operation with high brightness.
Microlensing of stars places significant constraints on subplanetary-mass compact objects, including primordial black holes, as dark matter candidates. As the lens' Einstein radius in the source ...plane becomes comparable to the size of the light source, however, source amplification is strongly suppressed, making it challenging to constrain lenses with a mass at or below 10−10 solar masses, i.e., asteroid-mass objects. Current constraints, using Subaru Hyper Suprime Cam (HSC) observations of M31, assume a fixed source size of one solar radius. However, the actual stars in M31 bright enough to be used for microlensing are typically much larger. We correct the HSC constraints by constructing a source size distribution based on the M31 PHAT survey and on a synthetic stellar catalog and by correspondingly weighting the finite-size source effects. We find that the actual HSC constraints are weaker by up to almost 3 orders of magnitude in some cases, broadening the range of masses for which primordial black holes can be the totality of the cosmological dark matter by almost 1 order of magnitude.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Abstract Memristor-based physical reservoir computing holds significant potential for efficiently processing complex spatiotemporal data, which is crucial for advancing artificial intelligence. ...However, owing to the single physical node mapping characteristic of traditional memristor reservoir computing, it inevitably induces high repeatability of eigenvalues to a certain extent and significantly limits the efficiency and performance of memristor-based reservoir computing for complex tasks. Hence, this work firstly reports an artificial light-emitting synaptic (LES) device with dual photoelectric output for reservoir computing, and a reservoir system with mixed physical nodes is proposed. The system effectively transforms the input signal into two eigenvalue outputs using a mixed physical node reservoir comprising distinct physical quantities, namely optical output with nonlinear optical effects and electrical output with memory characteristics. Unlike previously reported memristor-based reservoir systems, which pursue rich reservoir states in one physical dimension, our mixed physical node reservoir system can obtain reservoir states in two physical dimensions with one input without increasing the number and types of devices. The recognition rate of the artificial light-emitting synaptic reservoir system can achieve 97.22% in MNIST recognition. Furthermore, the recognition task of multichannel images can be realized through the nonlinear mapping of the photoelectric dual reservoir, resulting in a recognition accuracy of 99.25%. The mixed physical node reservoir computing proposed in this work is promising for implementing the development of photoelectric mixed neural networks and material-algorithm collaborative design.
X-ray crystallography has been central to the development of many fields of science over the past century. It has now matured to a point that as long as good-quality crystals are available, their ...atomic structure can be routinely determined in three dimensions. However, many samples in physics, chemistry, materials science, nanoscience, geology, and biology are noncrystalline, and thus their three-dimensional structures are not accessible by traditional x-ray crystallography. Overcoming this hurdle has required the development of new coherent imaging methods to harness new coherent x-ray light sources. Here we review the revolutionary advances that are transforming x-ray sources and imaging in the 21st century.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Abstract
The objective of this study was to analyze
O. rhinoceros
attraction to the pheromone that was placed near and far from the light source. Samples were obtained using pheromone traps placed at ...a distance of ± 5 m (near) and ± 500 m (far) from the light source. Each village was installed with 10 pheromone traps, 5 traps were placed near the light source, and another 5 traps were far from the light source. Observation on
O. rhinoceros
imago captured was conducted for 12 weeks. The results showed that
O. rhinoceros
is more attracted to the pheromone traps placed near the light source. The sex ratio of male and female imago from traps placed both near and far from the light were 1:1.2 and 1:1.3, respectively. This study can provide information regarding
O. rhinoceros
monitoring using pheromone traps combined with the light to attract more
O. rhinoceros
imago.
Gaia Early Data Release 3 Torra, F; Castañeda, J; Fabricius, C ...
Astronomy and astrophysics (Berlin),
05/2021, Volume:
649
Journal Article
Peer reviewed
Context. The Gaia Early Data Release 3 (Gaia EDR3) contains results derived from 78 billion individual field-of-view transits of 2.5 billion sources collected by the European Space Agency’s Gaia ...mission during its first 34 months of continuous scanning of the sky. Aims. We describe the input data, which have the form of onboard detections, and the modeling and processing that is involved in cross-matching these detections to sources. For the cross-match, we formed clusters of detections that were all linked to the same physical light source on the sky. Methods. As a first step, onboard detections that were deemed spurious were discarded. The remaining detections were then preliminarily associated with one or more sources in the existing source list in an observation-to-source match. All candidate matches that directly or indirectly were associated with the same source form a match candidate group. The detections from the same group were then subject to a cluster analysis. Each cluster was assigned a source identifier that normally was the same as the identifiers from Gaia DR2. Because the number of individual detections is very high, we also describe the efficient organising of the processing. Results. We present results and statistics for the final cross-match with particular emphasis on the more complicated cases that are relevant for the users of the Gaia catalogue. We describe the improvements over the earlier Gaia data releases, in particular for stars of high proper motion, for the brightest sources, for variable sources, and for close source pairs.
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FMFMET, NUK, UL, UM, UPUK
Narrow-linewidth lasers and optical frequency combs generated with mode-locked lasers have revolutionized optical frequency metrology. The advent of soliton Kerr frequency combs in compact ...crystalline or integrated ring optical microresonators has opened new horizons in academic research and industrial applications. These combs, as was naturally assumed, however, require narrow-linewidth, single-frequency pump lasers. We demonstrate that an ordinary cost-effective broadband Fabry–Pérot laser diode at the hundreds of milliwatts level, self-injection-locked to a microresonator, can be efficiently transformed to a powerful single-frequency, ultra-narrow-linewidth light source with further transformation to a coherent soliton comb oscillator. Our findings pave the way to the most compact and inexpensive highly coherent lasers, frequency comb sources, and comb-based devices for mass production.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, UL, UM, UPUK
Near-infrared luminescent materials exhibit unique photophysical properties that make them crucial components in photonic, optoelectronic and biological applications. As broadband near infrared ...phosphors activated by transition metal elements are already widely reported, there is a challenge for next-generation materials discovery by introducing rare earth activators with 4f-5d transition. Here, we report an unprecedented phosphor K
LuSi
O
:Eu
that gives an emission band centered at 740 nm with a full-width at half maximum of 160 nm upon 460 nm blue light excitation. Combined structural and spectral characterizations reveal a selective site occupation of divalent europium in LuO
and K2O
polyhedrons with small coordination numbers, leading to the unexpected near infrared emission. The fabricated phosphor-converted light-emitting diodes have great potential as a non-visible light source. Our work provides the design principle of near infrared emission in divalent europium-doped inorganic solid-state materials and could inspire future studies to further explore near-infrared light-emitting diodes.
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