The NASA InSight lander successfully placed a seismometer on the surface of Mars. Alongside, a hammering device was deployed that penetrated into the ground to attempt the first measurements of the ...planetary heat flow of Mars. The hammering of the heat probe generated repeated seismic signals that were registered by the seismometer and can potentially be used to image the shallow subsurface just below the lander. However, the broad frequency content of the seismic signals generated by the hammering extends beyond the Nyquist frequency governed by the seismometer's sampling rate of 100 samples per second. Here, we propose an algorithm to reconstruct the seismic signals beyond the classical sampling limits. We exploit the structure in the data due to thousands of repeated, only gradually varying hammering signals as the heat probe slowly penetrates into the ground. In addition, we make use of the fact that repeated hammering signals are sub-sampled differently due to the unsynchronised timing between the hammer strikes and the seismometer recordings. This allows us to reconstruct signals beyond the classical Nyquist frequency limit by enforcing a sparsity constraint on the signal in a modified Radon transform domain. Using both synthetic data and actual data recorded on Mars, we show how the proposed algorithm can be used to reconstruct the high-frequency hammering signal at very high resolution. In this way, we were able to constrain the seismic velocity of the top first meter of the Martian regolith.
Understanding the structure and processes of the deep interior of the planets is crucial for understanding their origin and evolution. As deep planetary interiors are inaccessible to direct ...observation, the most effective way to explore them is through geophysics, which provides tools for “remote sensing” of the interior. The four major classes of geophysical techniques that are used to probe planetary interiors are seismology, geodesy (which includes both gravimetry and planetary dynamics), heat flow, and electromagnetism. Seismology is the most powerful tool available for probing the interior of planets, and can provide detailed information on interior boundaries and clues about composition. Observations of gravity and rotation provide information on the distribution of mass within a planet due to overall structure (crust, mantle, core). Heat flow measurement provides information about the subsurface temperature structure and the energy driving interior processes. Electromagnetic techniques are primarily sensitive to temperature and the presence or absence of fluids or metallic phases.
Printing of active layers of high-efficiency organic solar cells and morphology control by processing with varying solvent additive concentrations are important to realize real-world use of ...bulk-heterojunction photovoltaics as it enables both up-scaling and optimization of the device performance. In this work, active layers of the conjugated polymer with benzodithiophene units PBDB-T-SF and the nonfullerene small molecule acceptor IT-4F are printed using meniscus guided slot-die coating. 1,8-Diiodooctane (DIO) is added to optimize the power conversion efficiency (PCE). The effect on the inner nanostructure and surface morphology of the material is studied for different solvent additive concentrations with grazing incidence small-angle X-ray scattering (GISAXS), grazing incidence wide-angle X-ray scattering (GIWAXS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Optical properties are studied with photoluminescence (PL), UV/vis absorption spectroscopy, and external quantum efficiency (EQE) measurements and correlated to the corresponding PCEs. The addition of 0.25 vol % DIO enhances the average PCE from 3.5 to 7.9%, whereas at higher concentrations the positive effect is less pronounced. A solar cell performance of 8.95% is obtained for the best printed device processed with an optimum solvent additive concentration. Thus, with the large-scale preparation method printing similarly well working solar cells can be realized as with the spin-coating method.
The amphiphilic diblock copolymer polystyrene-block-polyethylene oxide is combined with sol-gel chemistry to control the structure formation of blade-coated foam-like titania thin films. The ...influence of evaporation time before immersion into a poor solvent bath and polarity of the poor solvent bath are studied. Resulting morphological changes are quantified by scanning electron microscopy (SEM) and grazing incidence small angle X-ray scattering (GISAXS) measurements. SEM images surface structures while GISAXS accesses inner film structures. Due to the correlation of evaporation time and mobility of the polymer template during the phase separation process, a decrease in the distances of neighboring titania nanostructures from 50 nm to 22 nm is achieved. Furthermore, through an increase of polarity of an immersion bath the energetic incompatibility of the hydrophobic block and the solvent can be enhanced, leading to an increase of titania nanostructure distances from 35 nm to 55 nm. Thus, a simple approach is presented to control titania nanostructure in foam-like films prepared via blade coating, which enables an easy upscaling of film preparation.
Spray coating is employed to fabricate magnetic thin films composed of the diblock copolymer polystyrene‐block‐poly(N‐isopropylacrylamide) and Fe3O4 magnetic nanoparticles (MNPs) functionalized with ...hydrophobic coatings. The kinetics of structure formation of the hybrid films is followed in situ with grazing incidence small angle X‐ray scattering during the spray deposition. To gain a better understanding of the influence of MNPs on the overall structure formation, the pure polymer film is also deposited as a reference via an identical spray protocol. At the initial spraying stage, the hybrid film (containing 2 wt% of MNPs) exhibits a faster formation process of a complete film as compared to the reference. The existence of MNPs depresses the dewetting behavior of polymer films on the substrate at macroscale and simultaneously alters the polymer microphase separation structure orientation from parallel to vertical. As spraying proceeds, MNPs aggregate into agglomerates with increasing sizes. After the spray deposition is finished, both samples gradually reach an equilibrium state and magnetic films with stable structures are achieved in the end. Superconducting quantum interference device investigation reveals the superparamagnetic property of the sprayed hybrid film. Consequently, potential application of sprayed films in fields such as magnetic sensors or data storage appears highly promising.
Magnetic films composed of polystyrene‐block‐poly(N‐isopropylacrylamide) and magnetite nanoparticles (NPs) are fabricated by spray deposition. The kinetic structure evolution of the magnetic films is followed via in situ grazing incidence small angle X‐ray scattering. Compared with NP‐free polymer film, a faster formation process of a complete film and an alteration of the nanostructure orientation are observed for the hybrid one.
The objective of this study was to investigate the electroencephalographic reaction pattern and FOS protein expression in male piglets undergoing surgical castration under light isoflurane ...anaesthesia with or without local anaesthesia. The experiment was conducted under isoflurane anaesthesia to exclude the effect of the affective components of pain on the measurements. Changes in the oscillatory activity of the cerebral cortex over a 90 s period after noxious stimulation or simulated interventions were analysed. FOS expression was determined postmortem by performing immunohistochemistry in the dorsal horn of the spinal cord. The analysis of the response to an interdigital pinch revealed a biphasic reaction pattern in the electroencephalogram (EEG) that similarly was observed for the surgical stimuli during the castration procedure in the group without analgesia. This EEG response was attenuated or altered by the application of local anaesthetics. Immunohistochemical staining for FOS indicated a lower expression in the handling and in three local anaesthetic groups than in the animals castrated without pain relief. The findings indicate that EEG and FOS expression may serve as indicators for nociception in piglets under light isoflurane anaesthesia. A lower activation of nociceptive pathways occurs during castration after the application of local anaesthetics. However, EEG and FOS analyses should be combined with additional parameters to assess nociception, e.g., haemodynamic monitoring.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The development of polymer morphology and crystallinity of printed bulk heterojunction (BHJ) films doped with the different solvent additives 1,8‐diiodooctane (DIO) or diphenyl ether (DPE) is ...investigated with in situ grazing‐incidence small/wide‐angle X‐ray scattering. The solvent additives, having different boiling points, lead to a different film drying behavior and morphology growth states in the BHJ films of the benzothiadiazole‐based polymer (PPDT2FBT) and 6,6‐phenyl‐C71‐butyric acid methyl ester (PC71BM). The phase demixing in the printed films is changing over time along with solvent evaporation. Polymer domains start aggregating to form larger domains in the liquid–liquid phase, while phase separation mainly occurs in the liquid–solid phase. The present work provides a profound insight into the morphology development of printed BHJ films doped with different solvent additives, which is particularly important for the large‐scale fabrication of organic photovoltaics.
A detailed investigation of the polymer morphology and crystallinity development during the film formation process in the printed bulk heterojunction films shows differences in the kinetics depending on the used solvent additive. The choice of solvent additive is essential for the print process.
Printing of active layers for high‐efficiency organic solar cells with the slot‐die coating technique can overcome the challenge of upscaling, which will be needed for organic photovoltaics on its ...way to marketability. The morphology of a bulk‐heterojunction organic solar cell has a very high impact on its power conversion efficiency. Therefore, it is of particular importance to understand the mechanisms of structure formation during printing of active layers to enable further optimization of the solar cell performance and upscaling of the production process. Meniscus‐guided slot‐die coating of the blend of a low bandgap conjugated polymer donor with benzodithiophene units PBDB‐T‐SF and the nonfullerene small molecule acceptor IT‐4F is studied in situ with optical microscopy, Ultraviolet–visible spectroscopy, and grazing incidence small angle X‐ray scattering. The structure formation is followed from the liquid to the final dry film state. Thereby, five regimes of morphology formation are determined. The morphological evolution in the printed active layer is correlated to changing optical properties of the thin film. In the final dry film, polymer domains of several tens of nanometers are observed, which will be favorable for application in high‐efficiency organic solar cells.
Meniscus‐guided slot‐die coating of the blend of a low bandgap conjugated polymer donor with benzodithiophene units PBDB‐T‐SF and the nonfullerene small molecule acceptor IT‐4F is studied in situ using optical microscopy, UV–vis spectroscopy, and grazing incidence small angle X‐ray scattering. The structure formation is followed from the liquid to the final dry film state.
Non‐fullerene acceptor (NFA)‐based organic solar cells have made tremendous progress in recent years. For the neat NFA system PBDB‐T:ITIC, the film morphology and crystallinity are tailored by the ...choice of the solvent used for spin coating the active layers. Three different chlorinated solvents, chlorobenzene (CB), chloroform, and dichlorobenzene, are compared and the obtained active layer morphology is correlated with the optoelectronic properties and the device performance. The small domain sizes in the case of CB are most beneficial for the device performance, whereas the largest number or size of face‐on PBDB‐T crystallites is not causing the highest power conversion efficiencies (PCEs). In addition, when using CB, the number of edge‐on crystallites is highest and the distances between neighboring domains are small. The smoothest blend films are realized with CB, which exhibit correlated roughness with their substrates and no large aggregates have formed in these blend films. Thus, CB offers the best way to balance the aggregation and crystallization kinetics in the active layer and enables the highest PCE values.
By using different solvents for spin coating, the active layers of non‐fullerene‐based organic solar cells, the film morphology, and crystallinity of donor and acceptor are tailored. Among the studied solvents, chlorobenzene offers the best way to balance the aggregation and crystallization kinetics in the active layer and thus gives the best performing solar cells.
The amphiphilic diblock copolymer polystyrene-
block
-polyethylene oxide is combined with sol-gel chemistry to control the structure formation of blade-coated foam-like titania thin films. The ...influence of evaporation time before immersion into a poor solvent bath and polarity of the poor solvent bath are studied. Resulting morphological changes are quantified by scanning electron microscopy (SEM) and grazing incidence small angle X-ray scattering (GISAXS) measurements. SEM images surface structures while GISAXS accesses inner film structures. Due to the correlation of evaporation time and mobility of the polymer template during the phase separation process, a decrease in the distances of neighboring titania nanostructures from 50 nm to 22 nm is achieved. Furthermore, through an increase of polarity of an immersion bath the energetic incompatibility of the hydrophobic block and the solvent can be enhanced, leading to an increase of titania nanostructure distances from 35 nm to 55 nm. Thus, a simple approach is presented to control titania nanostructure in foam-like films prepared
via
blade coating, which enables an easy upscaling of film preparation.
Diblock copolymer templating combined with sol-gel chemistry is a powerful tool to control the morphology of titania nanostructures.
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