Insights into the naphthalenide-driven synthesis and reactivity of zerovalent iron nanoparticles

The chemical and thermal stability of alkali metal naphthalenides as powerful reducing agents are examined, including the type of alkali metal ([LiNaph] and [NaNaph]), the type of solvent (THF, DME), the temperature (−30 to +50 °C), and the time of storage (0 to 12 hours). The stability and concentration of [LiNaph]/[NaNaph] are quantified via UV-Vis spectroscopy and the Lambert–Beer law. As a result, the solutions of [LiNaph] in THF at low temperature turn out to be most stable. The decomposition can be related to a reductive polymerization of the solvent. The most stable [LiNaph] solutions in THF are exemplarily used to prepare reactive zerovalent iron nanoparticles, 2.3 ± 0.3 nm in size, by reduction of FeCl$_{3}$ in THF. Finally, the influence of [LiNaph] and/or remains of the starting materials and solvents upon controlled oxidation of the as-prepared Fe(0) nanoparticles with iodine in the presence of selected ligands is evaluated and results in four novel, single-crystalline iron compounds ([FeI$_{2}$(MeOH)$_{2}$], ([MePPh$_{3}$][FeI$_{3}$(Ph$_{3}$P)])$_{4}$·PPh$_{3}$·6C$_{7}$H$_{8}$, [FeI$_{2}$(PPh$_{3}$)$_{2}$], and [FeI$_{2}$(18-crown-6)]). Accordingly, reactive Fe(0) nanoparticles can be obtained in the liquid phase via [LiNaph]-driven reduction and instantaneously reacted to give new compounds without remains of the initial reduction (e.g. LiCl, naphthalene, and THF)

An anocellar polistine wasp (Hymenoptera, Vespidae, Polistinae) from Texas

A remarkable teratological female of Polistes (Fuscopolistes) dorsalis neotropicus Bequaert, 1940 (Vespidae: Polistinae) is described and illustrated. The specimen lacks all three external dorsal ocelli but is normally developed in almost every other aspect. Additionally, similar findings in other Hymenoptera are briefly discussed, as are the consequences and the reasons that might cause the random loss of ocelli

WHAT SHOULD AI KNOW? INFORMATION DISCLOSURE IN HUMAN-AI COLLABORATION

AI-assisted Design Thinking shows great potential for supporting collaborative creative work. To foster creative thinking processes within teams with individualized suggestions, AI has to rely on data provided by the teams. As a prerequisite, team members need to weigh their disclosure preferences against the potential benefits of AI when disclosing information. To shed light on these decisions, we identify relevant information such as emotional states or discussion arguments that design thinking teams could provide to AI to enjoy the benefits of its support. Using the privacy calculus as theoretical lens, we draft a research design to analyze user preferences for disclosing different information relevant to the service bundles that AI provides for respective information. We make explorative contributions to the body of knowledge in terms of AI use and its corresponding information disclosure. The findings are relevant for practice as they guide the design of AI that fosters information disclosure

π0\pi^0-Photoproduction on the deuteron via Δ\Delta-excitation using the Lorentz Integral Transform

The Lorentz Integral Transform method (LIT) is extended to pion photoproduction in the $\Delta$-resonance region. The main focus lies on the solution of the conceptual difficulties which arise if energy dependent operators for nucleon resonance excitations are considered. In order to demonstrate the applicability of our approach, we calculate the inclusive cross section for $\pi^0$-photoproduction off the deuteron within a simple pure resonance model.Comment: 4 pages, EPJA styl

Raman cooling and heating of two trapped Ba+ ions

We study cooling of the collective vibrational motion of two 138Ba+ ions confined in an electrodynamic trap and irradiated with laser light close to the resonances S_1/2-P_1/2 (493 nm) and P_1/2-D_3/2 (650 nm). The motional state of the ions is monitored by a spatially resolving photo multiplier. Depending on detuning and intensity of the cooling lasers, macroscopically different motional states corresponding to different ion temperatures are observed. We also derive the ions' temperature from detailed analytical calculations of laser cooling taking into account the Zeeman structure of the energy levels involved. The observed motional states perfectly match the calculated temperatures. Significant heating is observed in the vicinity of the dark resonances of the Zeeman-split S_1/2-D_3/2 Raman transitions. Here two-photon processes dominate the interaction between lasers and ions. Parameter regimes of laser light are identified that imply most efficient laser cooling.Comment: 8 pages, 5 figure

Simultaneous cooling of axial vibrational modes in a linear ion trap

In order to use a collection of trapped ions for experiments where a well-defined preparation of vibrational states is necessary, all vibrational modes have to be cooled to ensure precise and repeatable manipulation of the ions quantum states. A method for simultaneous sideband cooling of all axial vibrational modes is proposed. By application of a magnetic field gradient the absorption spectrum of each ion is modified such that sideband resonances of different vibrational modes coincide. The ion string is then irradiated with monochromatic electromagnetic radiation, in the optical or microwave regime, for sideband excitation. This cooling scheme is investigated in detailed numerical studies. Its application for initializing ion strings for quantum information processing is extensively discussed

Behind every domain there is a shift: adapting distortion-aware vision transformers for panoramic semantic segmentation

In this paper, we address panoramic semantic segmentation which is under-explored due to two critical challenges: (1) image distortions and object deformations on panoramas; (2) lack of semantic annotations in the 360◦ imagery. To tackle these problems, first, we propose the upgraded Transformer for Panoramic Semantic Segmentation, i.e., Trans4PASS+, equipped with Deformable Patch Embedding (DPE) and Deformable MLP (DMLPv2) modules for handling object deformations and image distortions whenever (before or after adaptation) and wherever (shallow or deep levels). Second, we enhance the Mutual Prototypical Adaptation (MPA) strategy via pseudo-label rectification for unsupervised domain adaptive panoramic segmentation. Third, aside from Pinhole-to-Panoramic (PIN2PAN) adaptation, we create a new dataset (SynPASS) with 9,080 panoramic images, facilitating Synthetic-to-Real (SYN2REAL) adaptation scheme in 360◦ imagery. Extensive experiments are conducted, which cover indoor and outdoor scenarios, and each of them is investigated with PIN2PAN and SYN2REAL regimens. Trans4PASS+ achieves state-of-the-art performances on four domain adaptive panoramic semantic segmentation benchmarks. Code is available at https://github.com/jamycheung/Trans4PASS

Asymptotic equivalence of discretely observed diffusion processes and their Euler scheme: small variance case

This paper establishes the global asymptotic equivalence, in the sense of the Le Cam $\Delta$-distance, between scalar diffusion models with unknown drift function and small variance on the one side, and nonparametric autoregressive models on the other side. The time horizon $T$ is kept fixed and both the cases of discrete and continuous observation of the path are treated. We allow non constant diffusion coefficient, bounded but possibly tending to zero. The asymptotic equivalences are established by constructing explicit equivalence mappings.Comment: 21 page