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Dimensional and contact resonance (CR) images of nanowire (NW) arrays (NWAs) are measured using our newly developed microprobe CR imaging (CRI) setup. Then a reference method is employed to calculate the indentation modulus of NWs (Mi,NW) representing the elasticity of NWs, by measuring NWAs and reference samples at the same static probing force. Furthermore, topography is imaged in combination with CR and Mi,NWseparately by software, in which the zvalues indicate the topography of the NWs and the color bars show its CR or Mi,NW. Then NWs’ topography relation to Mi,NWis visualized. As typical examples, 3D imaging of topography and measurement of Mi,NWis performed with Si<111> pillar arrays as well as Cu and ZnO NWAs. The novel method enables fast mechanical performance measurements of large-scale vertically-aligned NWAs without releasing them from their respective substrates. For instance, the diameter and pitch of the Si<111> pillars and the diameter of the Cu NWAs are in good agreement with the values measured by scanning electron microscopy (SEM). The position of ZnO NWs bunches grown at arbitrary sites on silicon can be identified with the help of combined topography and indentation modulus images. Furthermore, Mi,NWmeasured by our homemade CRI setup agrees well with bulk values. Differences between the measured Mi,NWand bulk Mivalues may be related to a size effect in NW elasticity.

The accurate detection and quantification of rodent behavior forms a cornerstone of basic biomedical research. Current data-driven approaches, which segment free exploratory behavior into clusters, suffer from low statistical power due to multiple testing, exhibit poor transferability across experiments and fail to exploit the rich behavioral profiles of individual animals. Here we introduce a pipeline to capture each animal’s behavioral flow, yielding a single metric based on all observed transitions between clusters. By stabilizing these clusters through machine learning, we ensure data transferability, while dimensionality reduction techniques facilitate detailed analysis of individual animals. We provide a large dataset of 771 behavior recordings of freely moving mice—including stress exposures, pharmacological and brain circuit interventions—to identify hidden treatment effects, reveal subtle variations on the level of individual animals and detect brain processes underlying specific interventions. Our pipeline, compatible with popular clustering methods, substantially enhances statistical power and enables predictions of an animal’s future behavior.

Im Projekt STellaR (Stationäre Telepräsenzberatung im ländlichen Raum) entwickelt, erprobt und evaluiert die Hochschule Bielefeld in Zusammenarbeit mit der Universität Trier sowie der beraterischen Praxis an ausgewählten Modellstandorten in ländlichen Regionen einen neuen Zugang zur Beratung. Fest installierte Videoberatungsräume in vertrauenswürdigen, öffentlich zugänglichen Einrichtungen sollen auch neue Möglichkeiten für das Blended Counseling bieten. STellaR wird im Programm Forschung an Fachhochschulendes Bundesministeriums für Bildung und Forschung seit September 2020 gefördert (BMBF-Förderkennzeichen 13FH034SX8). Der Text versteht sich als konzeptioneller Beitrag und thematisiert die Relevanz des Blended Counseling aus organisationaler Perspektive.

Der vorliegende Beitrag möchte den Analysen zur Digitalisierung in der Sozialen Arbeit eine arbeits- und interaktionssoziologische Perspektive hinzufügen. Auf diese Weise werden mögliche Vor- und Nachteile der Digitalisierung aus der Sicht von Fachkräften, Hilfsbedürftigen und Organisationen deutlich. Es zeigt sich, dass die im Zuge der Digitalisierung oft geäußerten Ängste und Hoffnungen hinsichtlich der Rationalisierung Sozialer Arbeit zu kurz greifen. Die Analyse wird durch arbeitssoziologische Überlegungen zur Dienstleistungsarbeit sowie die Interaktionstheorie Luhmanns theoretisch gerahmt. Letztere ist in eine Organisations- sowie eine umfassende Sozialtheorie eingebettet und bietet dadurch kohärente Anknüpfungspunkte für die Untersuchung der möglichen Auswirkungen der Nutzung digitaler Technologien in helfenden Interaktionen. Anstatt durch Standardisierung Abstimmungsprobleme zu reduzieren, dürfte die Nutzung digitaler Technologien vor allem neue Abstimmungsprobleme begünstigen.

The revolution of the GaN‐on‐Si hybrid integration has redefined microdisplay as a point‐light source for scientific, communication and visualization applications, thanks to their superior capabilities in terms of resolution, brightness and switching speed. In this work, we present a CMOS (Complementary Metal‐Oxide Semiconductor) backplane able to exploit the GaN microarrays capabilities, producing high‐speed patterns (up to 9.15 kfps) at high optical intensities (up to 120 uA per pixel and 16 grey levels) at an unprecedented resolution of 1411 PPI (512×512 pixel with 18um pitch). In addition, the backplane can be operated in pulsed mode, allowing the entire array to be toggled between the stored frame and off state at 1 MHz. Its unique characteristics expand the range of possible applications, from fluorescence‐based performance assays to the manufacturing of DNA chips.

GaN microLED technology has the potential to offer displays with high brightness, bandwidth, and long lifetime with a very low energy consumption. Moreover, GaN‐on‐Si hybrid interconnection technology allows the development of displays with a very high pixel density integration. In this work we present an in‐pixel driving circuit designed in a 0.18µm CMOS technology to be integrated on a 512x512 microLED array by using the KlettWelding hybrid interconnection technique forming a microLED display of 1411 ppi with 10kfps working speed. The pixel driver is able to achieve switching times of 1MHz and can be operated at high bias currents of 120µA. The individual driver consists of 4 SRAMs that apply a weighted current and allows to avoid the current stability problems associated to CMOS backplanes in hybridly interconnected displays.

Die zunehmende Bedeutung digitaler Plattformen für die moderne Gesellschaft wird bisher noch nicht hinreichend von einem übergreifenden Interesse an einer allgemeinen Theorie begleitet. Der Beitrag steuert aus systemtheoretischer Perspektive erste Vorarbeiten zu einem solchen Vorhaben bei. In Abgrenzung zu bestehenden Konzeptualisierungen digitaler Plattformen als Techniken, Märkte, Netzwerke oder Organisationen bestimmt er diese als soziale Systeme sui generis. Insbesondere das Festhalten am Organisationsbegriff eröffnet dabei aussichtsreiche Vergleichspunkte für Funktionsbestimmungen digitaler Plattformen. Anders als Organisationen konstituieren sich diese nicht durch die Konditionierung von Mitgliedschafts-, sondern von Sichtbarkeitserwartungen. Digitale Plattformen leisten analog zu Organisationen eine Maximierung der Generalisierung von Verhaltenserwartungen in allen drei Sinndimensionen zugleich. Anders als Organisationen leisten sie diese Maximierung aber zeitlich über Kognitionen, sachlich über Programme und sozial über materiell-technisierte Spuren.

The spread of white-nose syndrome into western North America has caused concerns that bat species inhabiting the region will soon experience population declines like those seen to the east. However, much of the region lacks baseline estimates of abundance for bats believed to be susceptible to WNS due to a scarcity of known hibernacula, where populations are traditionally monitored. The goal of this study was to determine the abundance, roost fidelity, and activity patterns of summer colonies of female little brown myotis (Myotis lucifugus) in an area with no known hibernacula. To accomplish this, we subcutaneously implanted passive integrated transponder (PIT) tags into 297 female little brown myotis from 2015 to 2018 and installed radio-frequency identification (RFID) readers and antennas inside three maternity roosts in Yellowstone National Park. Bats occupied RFID-monitored roosts on 32% of days and were never detected at maternity roosts located > 16 km from where they were tagged. Roost fidelity varied throughout summer and was greatest during late gestation and early lactation. This allowed us to combine nightly scans of RFID-tagged bats with visual emergence counts to estimate the population of bats using two roosts located >16 km apart during 2017–2018. Population estimates of both colonies were markedly higher (N*= 208 ± 6 bats and N*= 836 ± 67 bats during 2018) than the number of bats seen during evening emergence (high counts of 127 and 222, respectively). Nocturnal visits of tagged bats to these roosts increased around the time of parturition, indicative of bats returning to nurse young. These data show that emergence count and PIT tag data can be combined to monitor bat population abundance and activity patterns in areas where hibernacula are absent or where their locations are unknown.

Three-dimensional InGaN/GaN nano- and microstructures with high aspect ratios and large active sidewall areas are still of great interest in the field of optoelectronics. However, when grown by metalorganic chemical vapor deposition (MOCVD), their optical performance can be negatively affected by gradients in thickness and peak emission wavelength along their sidewalls, which is still a key obstacle for using such structures in commercial products. In this work, we present a detailed study on the different mechanisms causing this gradient, as well as means to alleviate it. Gas-phase mass transport and surface diffusion are found to be the two main processes governing the shell growth, and the predominance of one process over the other is varying with the geometry of the 3D structures as well as the spacing between them. Consequently, variations in temperature, which mainly affect surface diffusion, will have a stronger impact on structures with small separation between them rather than larger ones. On the other hand, variations in pressure modify gas-phase diffusion, and thus, structures with a large spacing will be more strongly affected. A proper design of the dimensions of 3D architectures as well as the separation between them may improve the gradient along the sidewalls, but a tradeoff with the active area per wafer footprint is inevitable.

This study examines what visitors to urban parks in Houston, TX, know about environmental health risks resulting from Hurricane Harvey, a category 4 storm that made landfall in August 2017 and dropped over 60 in. of rain in 8 days making it the most significant rainfall event in US history. Interviews were conducted with adult Houstonians using purposive sampling. In total, 27 interviews were conducted with 36 different participants. Interviews were audio-recorded, transcribed verbatim, and analyzed qualitatively using a phronetic iterative approach. This study found that park visitors lack sufficient knowledge about environmental health risks, yet they have strong desires to learn more about such risks. In particular, participants have clear opinions on what the content of the messages (i.e., concise, manageable, not fear-inducing) should be and how they would like to receive the information (i.e., conveniently accessible, from trusted local sources). Implications for health campaign interventions utilizing uncertainty theories are discussed.

Long-term complications after coronavirus disease 2019 (COVID-19) are common in hospitalized patients, but the spectrum of symptoms in milder cases needs further investigation. We conducted a long-term follow-up in a prospective cohort study of 312 patients—247 home-isolated and 65 hospitalized—comprising 82% of total cases in Bergen during the first pandemic wave in Norway. At 6 months, 61% (189/312) of all patients had persistent symptoms, which were independently associated with severity of initial illness, increased convalescent antibody titers and pre-existing chronic lung disease. We found that 52% (32/61) of home-isolated young adults, aged 16–30 years, had symptoms at 6 months, including loss of taste and/or smell (28%, 17/61), fatigue (21%, 13/61), dyspnea (13%, 8/61), impaired concentration (13%, 8/61) and memory problems (11%, 7/61). Our findings that young, home-isolated adults with mild COVID-19 are at risk of long-lasting dyspnea and cognitive symptoms highlight the importance of infection control measures, such as vaccination.

Biofouling is a major issue in membrane-based water treatment because it shortens membrane life and decreases the permeate flux. Silver, a known biocide, is often used for in situformation of silver nanoparticles (Ag NPs) on membranes for biofouling mitigation. However, Ag NPs dissolve quickly in water, limiting their effectiveness over long periods of time. This study focuses on the modification of silver-functionalized reverse osmosis (RO) membranes with different concentrations of Na2S (10−1, 10−3, and 10−5M) to identify the degree of sulfidation that limits Ag release while preserving the antibacterial effect. Sulfidized membranes decreased Ag release by >85% depending on the extent of sulfidation. Antibacterial activity was assessed using Pseudomonas aeruginosaand Escherichiacoli. Results showed the highest inactivation at 73% for P. aeruginosaand 57% for E. colifor 10−5and 10−3M Na2S-treated membranes, respectively, while the more sulfidized membrane treated with 10−1M Na2S treatment had the lowest antibacterial effect. Moreover, when tested in a dynamic cross-flow RO system for 24 h, the flux declined by 24% for the Ag NPs and by 23%, 17%, and 19% as the extent of sulfidation increased. Additionally, the Ag remaining on the membrane was higher for the highest sulfidized membrane with 519 ng cm−2. Therefore, retention of the silver coating over time appears to be more important for biofilm control in RO systems than high antibacterial activity. Both 10−5M and 10−3M Na2S-treated membranes had the best balance between reduced Ag release rate and effective antibacterial and anti-biofouling performance, respectively.

Adsorption-induced deformation of a series of silica samples with hierarchical porosity has been studied by in situ small-angle neutron scattering (SANS) and in situ dilatometry. Monolithic samples consisted of a disordered macroporous network of struts formed by a 2D lattice of hexagonally ordered cylindrical mesopores and disordered micropores within the mesopore walls. Strain isotherms were obtained at the mesopore level by analyzing the shift of the Bragg reflections from the ordered mesopore lattice in SANS data. Thus, SANS essentially measured the radial strain of the cylindrical mesopores including the volume changes of the mesopore walls due to micropore deformation. A H2O/D2O adsorbate with net zero coherent neutron scattering length density was employed in order to avoid apparent strain effects due to intensity changes during pore filling. In contrast to SANS, the strain isotherms obtained from in situ dilatometry result from a combination of axial and radial mesopore deformation together with micropore deformation. Strain data were quantitatively analyzed with a theoretical model for micro-/mesopore deformation by combining information from nitrogen and water adsorption isotherms to estimate the water–silica interaction. It was shown that in situ SANS provides complementary information to dilatometry and allows for a quantitative estimate of the elastic properties of the mesopore walls from water adsorption.

Mechanical properties of hierarchically structured nanoporous materials are determined by the solid phase stiffness and the pore network morphology. We analyze the mechanical stiffness of hierarchically structured silica monoliths synthesized via a sol–gel process, which possess a macroporous scaffold built of interconnected struts with hexagonally ordered cylindrical mesopores. We consider samples with and without microporosity within the mesopore walls and analyze them on the macroscopic level as well as on the microscopic level of the mesopores. Untreated as-prepared samples still containing some organic components and the respective calcined and sintered counterparts of varying microporosity are investigated. To determine Young’s moduli on the level of the macroscopic monoliths, we apply ultrasonic run time measurements, while Young’s moduli of the mesopore walls are obtained by analysis of the in situ strain isotherms during N2adsorption at 77 K. For the latter, we extended our previously reported theoretical approach for this type of materials by incorporating the micropore effects, which are clearly not negligible in the calcined and most of the sintered samples. The comparison of the macro- and microscopic Young’s moduli reveals that both properties follow essentially the same trends, that is, calcination and sintering increase the mechanical stiffness on both levels. Consequently, stiffening of the monolithic samples can be primarily attributed to stiffening of the backbone material which is consistent with the fact that the morphology on the mesopore level is mainly preserved with the post-treatments applied.

Photoelectrochemical (PEC) solar water splitting is a promising approach to convert solar energy into sustainable hydrogen fuel using semiconductor electrodes. Owing to their visible light absorption properties, oxynitrides have shown to be attractive photocatalysts for this application. In this study, the influence of the preparation method of CaNbO2N particles on their morphological and optical properties, and thereby their PEC performance, is investigated. The best performing CaNbO2N photoanode is produced by ammonolysis of Nb-enriched calcium niobium oxide. The enhanced photoactivity arises from an enlarged surface area and superior visible light absorption properties. The photoactivity of this photoanode was further enhanced by photodeposition of CoPi cocatalyst and by the atomic layer deposition of an Al2O3overlayer. A photocurrent density of 70 μA cm–2at 1.23 V versus reversible hydrogen electrode was achieved. The observed enhancement of the PEC performance after CoPi/Al2O3deposition is the combined effect of the improved kinetics of oxygen evolution because of the CoPi cocatalyst and the reduced surface recombination of the photogenerated carriers at the Al2O3surface layer.

We describe the major requirements to experimentally perform and observe resonant spin-flip Raman scattering on excitonic resonances in low-dimensional semiconductors. We characterize in detail the properties of this resonant light scattering technique and evaluate the criteria, which must be fulfilled by the experimental setup and the semiconductor sample studied to be able to observe a spin-flip scattering process. We also demonstrate the influence of additional unpolarized laser illumination with energies, which exceed considerably the band gap energy of the semiconductor nanostructure under study, on the resonantly excited electron spin-flip scattering in InAs-based quantum dot ensembles as well as on the paramagnetic Mn-ion spin-flip in (Zn,Mn)Se/(Zn,Be)Se quantum wells.

We report on the surface functionalization of ZnO nanowire (NW) arrays by attachment of carbon nanodots (C-dots) stabilized by polyethylenimine. The photoconductive properties of the ZnO NWs/C-dots devices were investigated under photoexcitation with photon energies below and above the ZnO band gap. The results indicate an increased photoresponse of the functionalized devices in the visible spectral range, as well as enhanced UV photoconductivity. This is attributed to the fast injection of photoexcited electrons from the C-dots into the conduction band of the ZnO NWs, and the subsequent slower desorption of molecular species from the NW surface, which reduces the surface depletion region in the NWs. The surface functionalization of the ZnO NWs with carbon nanodots also impacts the dynamics of the photocurrent decay, inducing a slower relaxation of the photogenerated charge carriers.

The commonly observed absorption around 265 nm in AlN is hampering the outcoupling efficiency of light‐emitting diodes (LEDs) emitting in the UV‐C regime. Carbon impurities in the nitrogen sublattice (CN) of AlN are believed to be the origin of this absorption. A specially tailored experiment using a combination of ion implantation of boron, carbon, and neon with subsequent high‐temperature annealing allows to separate the influence of intrinsic point defects and carbon impurities regarding this absorption. Herein, the presented results reveal the relevance of the intrinsic nitrogen‐vacancy defect VN. This is in contradiction to the established explanation based on CNdefects as the defect causing the 265 nm absorption and will be crucial for further UV‐LED improvement. Finally, in this article, a new interpretation of the 265 nm absorption is introduced, which is corroborated by density functional theory (DFT) results from the past decade, which are reviewed and discussed based on the new findings. The commonly observed absorption around 265 nm in AlN is hampering the outcoupling efficiency of light‐emitting diodes (LEDs) emitting in the UV‐C regime. A specially tailored experiment using a combination on ion implantation with subsequent high‐temperature annealing opens the interpretation of UV absorption for a revision and questions the role of carbon in the 265 nm absorption band.

Herein, carbon‐implanted high‐temperature annealed (HTA) AlN layers are analyzed and donor–acceptor pair (DAP) transitions probably between the two most abundant impurities, carbon and oxygen, are identified. Both are regarded as the main, hard‐to‐avoid impurities in crystal growth. Oxygen is believed to lead to absorption in the deep UV below a wavelength of 250 nm. In contrast, carbon is the most likely candidate to be responsible for a distinct absorption band around 265 nm. This interpretation has recently been challenged. In this study, carbon‐implanted and HTA AlN layers with ion fluences above 8.1 × 1015cm−2are analyzed using low‐temperature and time‐resolved cathodoluminescence spectroscopy. Due to the high concentration of oxygen inside the AlN, as a result of the HTA process, a DAP transition between a most likely carbon‐related acceptor and ONis observed. The measured temperature‐ and power‐dependent blueshift of the peak emission energy as well as the luminescence transients can be clearly explained by a continuous change from a DAP transition at low temperature to a free electron to acceptor transition with increasing temperature. The findings are supported by a configurational coordinate model that describes the measured behavior qualitatively. A donor–acceptor pair transition in aluminum nitride is identified, probably between the most abundant impurities during crystal growth: carbon and oxygen. High concentrations of both species are realized by ion implantation and diffusion during annealing. The identification is based on continuous‐wave and time‐resolved cathodoluminescence measurements at low and high temperatures plus theoretical considerations.

Abstract

In this work, the thermal decomposition of GaN three-dimensional (3D) microstructures was studied in an attempt to better understand the peculiarities of the complex growth process. Microfins with nonpolar a-plane sidewall facets have been investigated as model structures, and the influence of initial geometry and different annealing conditions in a metal–organic chemical vapor deposition reactor on the thermal reshaping has been investigated. We demonstrate that the annealing of these structures in an ammonia-containing atmosphere, which is comparable to that used during overgrowth, results in the decomposition of the c-plane top surfaces, diffusion of gallium adatoms to the a-plane sidewalls, and their reincorporation on these facets. Such behavior is attributed to the differences in thermal stability of the polar and nonpolar surfaces. By studying the thermal decomposition of microfins with varying geometry, we show that this phenomenon depends mainly on the aspect ratio of these structures. We attribute the strongly enhanced decomposition rate of high-aspect-ratio microstructures to the depletion of the gallium adlayer by adjacent crystal facets, which is the main factor discerning the growth of 3D microstructures from the planar case. Additionally, a simplified model for thermal decomposition involving the main physical mechanisms was proposed and applied to reproduce the experimentally observed behavior. The modeling procedure allows the experimental determination of the diffusion coefficients of gallium adatoms on the a-plane surface under the growth conditions applied. This work highlights the high sensitivity of 3D microstructures to thermal decomposition and offers a toolbox to understand their dependence on the geometry. A proper comprehension of thermal decomposition enables superior control of the GaN overgrowth on 3D topographies, which is a crucial approach for realizing novel device architectures relevant for power electronics or microLED displays.