A squeezed light source operated under high vacuum.
Ontology highlight
ABSTRACT:
SUBMITTER: Wade AR
PROVIDER: S-EPMC4677301 | biostudies-other | 2015
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Although vacuum-deposited metal halide perovskite light-emitting diodes (PeLEDs) have great promise for use in large-area high-color-gamut displays, the efficiency of vacuum-sublimed PeLEDs currently lags that of solution-processed counterparts. In this study, highly efficient vacuum-deposited PeLEDs are prepared through a process of optimizing the stoichiometric ratio of the sublimed precursors under high vacuum and incorporating ultrathin under- and upper-layers for the perovskite emission layer (EML). In contrast to the situation in most vacuum-deposited organic light-emitting devices, the properties of these perovskite EMLs are highly influenced by the presence and nature of the upper- and presublimed materials, thereby allowing us to enhance the performance of the resulting devices. By eliminating Pb° formation and passivating defects in the perovskite EMLs, the PeLEDs achieve an outstanding external quantum efficiency (EQE) of 10.9% when applying a very smooth and flat geometry; it reaches an extraordinarily high value of 21.1% when integrating a light out-coupling structure, breaking through the 10% EQE milestone of vacuum-deposited PeLEDs.
| S-EPMC10074115 | biostudies-literature
Project description:Prolonging wear life of amorphous carbon films under vacuum was an enormous challenge. In this work, we firstly reported that amorphous carbon film as a lubricant layer containing hydrogen, oxygen, fluorine and silicon (a-C:H:O:F:Si) exhibited low friction (~0.1), ultra-low wear rate (9.0 × 10(-13) mm(3) N(-1) mm(-1)) and ultra-long wear life (>2 × 10(6) cycles) under high vacuum. We systematically examined microstructure and composition of transfer film for understanding of the underlying frictional mechanism, which suggested that the extraordinarily excellent tribological properties were attributed to the thermodynamically and structurally stable FeF2 nanocrystallites corroborated using first-principles calculations, which were induced by the tribochemical reaction.
| S-EPMC4461914 | biostudies-literature
Project description:Scanning electron microscopes (SEM), which image sample surfaces by scanning with an electron beam, are widely used for steric observations of resting samples in basic and applied biology. Various conventional methods exist for SEM sample preparation. However, conventional SEM is not a good tool to observe living organisms because of the associated exposure to high vacuum pressure and electron beam radiation. Here we attempted SEM observations of live ticks. During 1.5×10(-3) Pa vacuum pressure and electron beam irradiation with accelerated voltages (2-5 kV), many ticks remained alive and moved their legs. After 30-min observation, we removed the ticks from the SEM stage; they could walk actively under atmospheric pressure. When we tested 20 ticks (8 female adults and 12 nymphs), they survived for two days after SEM observation. These results indicate the resistance of ticks against SEM observation. Our second survival test showed that the electron beam, not vacuum conditions, results in tick death. Moreover, we describe the reaction of their legs to electron beam exposure. These findings open the new possibility of SEM observation of living organisms and showed the resistance of living ticks to vacuum condition in SEM. These data also indicate, for the first time, the usefulness of tick as a model system for biology under extreme condition.
| S-EPMC3303806 | biostudies-literature
Project description:Nuclear-grade graphite is a high-efficiency material, widely used for vacuum applications in nuclear reactors and accelerators as targets facing particle beams. In these contexts, graphite is often exposed to extreme thermal stresses altering its physical and chemical properties. The thermal-induced release of volatile contaminants from targets and the damage of structural components are critical issues that can affect the safety and operation efficiency of beamline facilities. Here, we provide for the first time a detailed picture of the chemical and morphological changes occurring in a nuclear-grade graphite target, obtained through Electrical Discharge Machining (EDM), when exposed in vacuum to high temperatures. The radial temperature gradient induced by the impact of a pulsed energetic (MeV- GeV range) focused particle beams was reproduced by cyclically heating, in the 1300-1800 K temperature range, a disc-shaped graphite target in a vacuum setup. An accurate surface and in-depth chemical analysis of the graphite target was obtained thanks to the high sensitivity (ppm/ppb) of the Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) technique. The chemical maps clearly show the presence of several metal oxides and impurities in the surface and subsurface regions of the untreated sample. Such contaminants were removed because of the thermal treatment in vacuum more or less efficiently, as demonstrated by Thermogravimetric analysis (TGA), X-ray Photoelectron Spectroscopy (XPS), and ToF-SIMS. However, Raman spectroscopy and SEM-EDS revealed that the high-temperature treatment induces a decrease in the crystallite size of the graphite as well as changes in the target surface porosity with the appearance of microvoids, leading the graphite target to be more prone to the breakage.
| S-EPMC11341341 | biostudies-literature
Project description:We report experiments on crystallization of highly undercooled forsterite melt droplets under atmospheric and sub-atmospheric pressure conditions. Experiments have been conducted under non-contact conditions using the principles of aero-dynamic levitation. Real time dynamics of solidification, along with the transient evolution of surface textures, have been recorded using high speed camera for three cooling rates. These images have been matched with the time-tagged temperature data to understand the effect of pressure conditions and cooling rates on the crystallization dynamics. Compared to normal pressure, relatively higher levels of undercooling could be achieved under sub-atmospheric conditions. Results showed a strong dependence of surface textures on pressure conditions. For any externally employed cooling rate, relatively small length scale morphological textures were observed under sub-atmospheric conditions, in comparison to those achieved under ambient conditions. The observed trends have been explained on the basis of influence of pressure conditions on recalescence phenomenon and the rate at which latent heat of crystallization gets dissipated from the volume of the molten droplet. Sub-atmospheric experiments have also been performed to reproduce one of the classical chondrule textures, namely the rim + dendrite double structure. Possible formation conditions of this double structure have been discussed vis-à-vis those reported in the limited literature. To the best of our knowledge, the reported study is one of the first attempts to reproduce chondrules-like textures from highly undercooled forsterite melt droplets under sub-atmospheric non-contact conditions.
| S-EPMC7708509 | biostudies-literature
Project description:The cost of providing lighting in greenhouses and plant factories can be high. In the case of variable electricity prices, providing most of the light when electricity prices are low can reduce costs. However, it is not clear how plants respond to the resulting fluctuating light levels. We hypothesized that plants that receive a constant photosynthetic photon flux density (PPFD) will produce more biomass than those grown under fluctuating light levels. To understand potential growth reductions caused by fluctuating light levels, we quantified the effects of fluctuating PPFD on the photosynthetic physiology, morphology, and growth of 'Little Gem' and 'Green Salad Bowl' lettuce. Plants were grown in a growth chamber with dimmable white LED bars, alternating between high and low PPFDs every 15 min. The PPFDs were ∼400/0, 360/40, 320/80, 280/120, 240/160, and 200/200 μmol⋅m-2⋅s-1, with a photoperiod of 16 h and a DLI of ∼11.5 mol⋅m-2⋅day-1 in all treatments. CO2 was ∼800 μmol⋅mol-1. Plants in the 400/0 μmol⋅m-2⋅s-1 treatment had ∼69% lower An,30 (net assimilation averaged over 15 min at high and 15 min at low PPFD) than plants grown at a PPFD of 320/80 μmol⋅m-2⋅s-1 (or treatments with smaller PPFD fluctuations). The low An,30 in the 400/0, and to a lesser extent the 360/40 μmol⋅m-2⋅s-1 treatment was caused by low net assimilation at 360 and 400 μmol⋅m-2⋅s-1. Plants grown at 400/0 μmol⋅m-2⋅s-1 also had fewer leaves and lower chlorophyll content compared to those in other treatments. The four treatments with the smallest PPFD fluctuations produced plants with similar numbers of leaves, chlorophyll content, specific leaf area (SLA), dry mass, and leaf area. Chlorophyll content, An,30, and dry mass were positively correlated with each other. Our results show that lettuce tolerates a wide range of fluctuating PPFD without negative effects on growth and development. However, when fluctuations in PPFD are extreme (400/0 or 360/40 μmol⋅m-2⋅s-1), chlorophyll levels and An,30 are low, which can explain the low poor growth in these treatments. The ability of lettuce to tolerate a wide range of fluctuating light levels suggests that PPFD can be adjusted in response to variable electricity pricing.
| S-EPMC7875872 | biostudies-literature
Project description:We have investigated the genomic response of Arabidopsis cell suspension culture under high light. Our main goal has been twofold: first, to establish whether chloroplasts in Arabidopsis cell suspension culture are functional and, as such, can act as sensors of adverse external stimuli leading to the activation of genomic defence responses in a manner similar to that described in whole plants exposed to a wide range of environmental stresses and; second, to distinguish which of the ROS that would be probably generated in the chloroplasts is predominant. Our functional genomic analysis has led us to conclude that singlet oxygen is the major ROS in Arabidopsis cell suspension culture under high light stress and that singlet oxygen production is responsible for a genomic activation associated with the biosynthesis and signalling pathway of several phytohormones that ultimately triggers accelerated cell death.
2011-05-05 | GSE22671 | GEO
Project description:To characterize Arabidopsis proteomics and transcritomics changes in response to high light treatment. We quantify specific transcipts and protein abundance changes under both control and high light stress conditions. We aim to investigate the causality and interconnection of transcription and protein abundance change by an in-depth analysis of protein turnover, RNA-seq and 15N spike-in quantitative proteomics.
2022-05-05 | PXD010889 | Pride
Project description:Waveform-stabilized laser pulses have revolutionized the exploration of the electronic structure and dynamics of matter by serving as the technological basis for frequency-comb and attosecond spectroscopy. Their primary sources, mode-locked titanium-doped sapphire lasers and erbium/ytterbium-doped fibre lasers, deliver pulses with several nanojoules energy, which is insufficient for many important applications. Here we present the waveform-stabilized light source that is scalable to microjoule energy levels at the full (megahertz) repetition rate of the laser oscillator. A diode-pumped Kerr-lens-mode-locked Yb:YAG thin-disk laser combined with extracavity pulse compression yields waveform-stabilized few-cycle pulses (7.7?fs, 2.2 cycles) with a pulse energy of 0.15??J and an average power of 6?W. The demonstrated concept is scalable to pulse energies of several microjoules and near-gigawatt peak powers. The generation of attosecond pulses at the full repetition rate of the oscillator comes into reach. The presented system could serve as a primary source for frequency combs in the mid infrared and vacuum UV with unprecedented high power levels.
| S-EPMC4432647 | biostudies-literature
Project description:Two azobenzene ?-cyclodextrin based nanovalves are designed, synthesized and assembled on mesoporous silica nanoparticles. Under aqueous conditions, the cyclodextrin cap is tightly bound to the azobenzene moiety and capable of holding back loaded cargo molecules. Upon irradiation with a near-UV light laser, trans to cis-photoisomerization of azobenzene initiates a dethreading process, which causes the cyclodextrin cap to unbind followed by the release of cargo. The addition of a bulky stopper to the end of the stalk allows this design to be reversible; complete dethreading of cyclodextrin as a result of unbinding with azobenzene is prevented as a consequence of steric interference. As a result, thermal relaxation of cis- to trans-azobenzene allows for the rebinding of cyclodextrin and resealing of the nanopores, a process which entraps the remaining cargo. Two stalks were designed with different lengths and tested with alizarin red S and propidium iodide. No cargo release was observed prior to light irradiation, and the system was capable of multiuse. On/off control was also demonstrated by monitoring the release of cargo when the light stimulus was applied and removed, respectively.
| S-EPMC4305341 | biostudies-literature