Spontaneous fission of neutron-deficient fermium isotopes and the new nucleus 241Fm

Spontaneous fission of neutron-deficient fermium isotopes (N ≤ 144) was investigated. The nuclei were produced in fusion-evaporation reactions of ⁴⁰Ar beams with ^{204,206–208}Pb targets. Excitation functions of the two-and three-neutron evaporation channels were measured. The new isotope ²⁴¹Fm was identified, and its decay properties were determined. A previously made assignment of a 0.8 ms spontaneous-fission activity to the isotope ²⁴²Fm could not be confirmed. Isomeric states were not observed in any of the investigated isotopes. The experiments were performed at the velocity filter SHIP of GSI in Darmstadt.     

Novel Phosphonium-Based Ionic Liquid Electrolytes for Battery Applications

In this study, we address the fundamental question of the physicochemical and electrochemical properties of phosphonium-based ionic liquids containing the counter-ions bis(trifluoromethanesulfonyl)imide ([TFSI]⁻) and bis(fluorosulfonyl)imide ([FSI]⁻). To clarify these structure–property as well as structure–activity relationships, trimethyl-based alkyl- and ether-containing phosphonium ILs were systematically synthesized, and their properties, namely density, flow characteristics, alkali metal compatibility, oxidative stability, aluminum corrosivity as well as their use in Li-ion cells were examined comprehensively. The variable moiety on the phosphonium cation exhibited a chain length of four and five, respectively. The properties were discussed as a function of the side chain, counter-ion and salt addition ([Li][TFSI] or [Li][FSI]). High stability coupled with good flow characteristics were found for the phosphonium IL [P1114][TFSI] and the mixture [P1114][TFSI] + [Li][TFSI], respectively.     

Unsaturated Ruthenium Hydrides as Reactive Intermediates: An Experimental Investigation and Theoretical Model Study of (dtbpm‐κ2P)Ru(H)Cl, (dtbpe‐κ2P)Ru(H)Cl and Their Dinuclear Dynamic Precursor Complexes

A detailed spectroscopic and quantum‐chemical structure investigation of the dinuclear, 16‐valence‐electron complexes [(^tBu₂P(CH₂)_nP^tBu₂‐κ²P)RuH]₂(μ₂‐Cl)₂ (n=1, 2), stabilized by the bulky, electron‐rich chelating ligands bis[di(t‐butyl)phosphano]methane (^tBu₂PCH₂P^tBu₂, dtbpm) and 1,2‐bis[di(t‐butyl)phosphano]ethane (^tBu₂PCH₂CH₂P^tBu₂, dtbpe) is reported. VT‐NMR Spectroscopy of [(dtbpm‐κ²P)RuH]₂(μ₂‐Cl)₂, an important precursor of olefin metathesis catalysts, and of its homologue [(dtbpe‐κ²P)RuH]₂(μ₂‐Cl)₂ reveals facile interconversion of dinuclear cis‐ and trans‐dihydride isomers for both systems. Crossover experiments provide evidence for the existence of short‐lived, mononuclear intermediates (dtbpm‐κ²P)Ru(H)Cl and (dtbpe‐κ²P)Ru(H)Cl in solution. Mechanistic features of the cis‐trans isomerization process as well as structural and electronic properties of model systems for the dinuclear complexes and mononuclear intermediates were treated theoretically by DFT calculations.     

Preclassification of Broadband and Sparse Infrared Data by Multiplicative Signal Correction Approach

Preclassification of raw infrared spectra has often been neglected in scientific literature. Separating spectra of low spectral quality, due to low signal-to-noise ratio, presence of artifacts, and low analyte presence, is crucial for accurate model development. Furthermore, it is very important for sparse data, where it becomes challenging to visually inspect spectra of different natures. Hence, a preclassification approach to separate infrared spectra for sparse data is needed. In this study, we propose a preclassification approach based on Multiplicative Signal Correction (MSC). The MSC approach was applied on human and the bovine knee cartilage broadband Fourier Transform Infrared (FTIR) spectra and on a sparse data subset comprising of only seven wavelengths. The goal of the preclassification was to separate spectra with analyte-rich signals (i.e., cartilage) from spectra with analyte-poor (and high-matrix) signals (i.e., water). The human datasets 1 and 2 contained 814 and 815 spectra, while the bovine dataset contained 396 spectra. A pure water spectrum was used as a reference spectrum in the MSC approach. A threshold for the root mean square error (RMSE) was used to separate cartilage from water spectra for broadband and the sparse spectral data. Additionally, standard noise-to-ratio and principle component analysis were applied on broadband spectra. The fully automated MSC preclassification approach, using water as reference spectrum, performed as well as the manual visual inspection. Moreover, it enabled not only separation of cartilage from water spectra in broadband spectral datasets, but also in sparse datasets where manual visual inspection cannot be applied.     

Single tungsten nanowires as pH sensitive electrodes

The electrochemical potentials of tungsten nanowire samples, covered with their own oxide, were measured in dependence of the pH value. The samples were prepared by selective etching of a directionally solidified eutectic NiAl–W alloy. Directional solidification in a Bridgman-type crystal growth furnace yields nanostructured two-phase materials. Electrochemical processing allows selective etching of the phases exposing the nanoscale structures. In this work, pointed samples with a single wire 200 nm in diameter protruding from the tip were produced. Subsequently the tungsten oxide layer on these single nanowires was electrochemically modified to optimize their pH sensing capabilities. The method has a potential for further downsizing since the wire diameter and exposed length can be controlled by the process parameters during solidification and during electrochemical processing. The advantages of these nanowire pH probes along with possible applications such as the pH measurement in ultra small cavities and other small systems of interest such as corrosion pits and biological cells are discussed.     

Industrial perspective on focused electron beam-induced processes

After a short overview of the historical developments of the technique of gas-assisted focused electron beam-induced processing (mostly deposition and etching), this paper deals with the applications of this technology to photolithographic mask repair. A commented list of results is shown on different mask types, for different types of defects, and at different node generations. The scope of this article is double: summarize the state of the art in a fast-paced highly specific industrial environment driven by “Moore’s law” and feedback to academic researchers some technologically relevant directions for further investigations.