A new version of the ''modified total evaporation'' (MTE) method for isotopic analysis of uranium samples by multi-collector thermal ionization mass spectrometry (TIMS), with high analytical performance and designed in a more user-friendly and routinely applicable way, is described in detail. It is mainly being used for nuclear safeguards measurements, but can readily be applied in other scientific areas like geochemistry. The development of the MTE method was organized in collaboration of several ''key nuclear mass spectrometry laboratories'', namely the New Brunswick Laboratory (NBL), the Safeguards Analytical Laboratory (SAL, now SGAS-Safeguards Analytical Services) of the International Atomic Energy Agency (IAEA), the Institute for Transuranium Elements (ITU/JRC), and the Institute for Reference Materials and Measurements (IRMM/JRC), with IRMM taking the leading role. Due to the use of the ''total evaporation'' (TE) principle the measurement of the ''major'' ratio n( 235 U)/n( 238 U) is routinely being performed with an accuracy of 0.02%. In contrast to the TE method, in the MTE method the total evaporation process is interrupted on a regular basis to allow for correction for background from peak tailing, internal calibration of a secondary electron multiplier (SEM) detector versus the Faraday cups, peak-centering, and ion source re-focusing. Therefore, the most significant improvement using the MTE method is in the measurement performance achieved for the ''minor'' ratios n( 234 U)/n( 238 U) and n( 236 U)/n( 238 U). The n( 234 U)/n( 238 U) ratio is measured using Faraday cups only with the result that the (relative) measurement uncertainty (k ¼ 2) is better than 0.12%, which is an improvement by a factor of about 5-10 compared to TE measurements. Furthermore, the IAEA requirement for the ''measurement performance'', defined here as the sum of the (absolute) deviation of the measured from the true (certified) value plus the (absolute) measurement uncertainty (k ¼ 2), for n( 236 U)/n( 238 U) ratio measurements is 1 Â 10 À6 , but the MTE method provides a measurement performance which is, depending on the ratio, by several orders of magnitude superior compared to this limit and to the TE method. For routine MTE measurements a detection limit of 3 Â 10 À9 was achieved using an SEM detector for detecting the isotope 236 U. The MTE method is now routinely being used at all collaborating laboratories with the hope that more laboratories will implement this capability in the future as well. Additional applications for the MTE method are presented in this paper, e.g., for absolute Ca isotope measurements. 238U are usually considered as the major isotopes, whereas 234 U and 236 U are called minor isotopes. Natural uranium variations

Low dimensionality and high flexibility are key demands for flexible electronic semiconductor devices. SnIP, the first atomic‐scale double helical semiconductor combines structural anisotropy and robustness with exceptional electronic properties. The benefit of the double helix, combined with a diverse structure on the nanoscale, ranging from strong covalent bonding to weak van der Waals interactions, and the large structure and property anisotropy offer substantial potential for applications in energy conversion and water splitting. It represents the next logical step in downscaling the inorganic semiconductors from classical 3D systems, via 2D semiconductors like MXenes or transition metal dichalcogenides, to the first downsizeable, polymer‐like atomic‐scale 1D semiconductor SnIP. SnIP shows intriguing mechanical properties featuring a bulk modulus three times lower than any IV, III‐V, or II‐VI semiconductor. In situ bending tests substantiate that pure SnIP fibers can be bent without an effect on their bonding properties. Organic and inorganic hybrids are prepared illustrating that SnIP is a candidate to fabricate flexible 1D composites for energy conversion and water splitting applications. SnIP@C3N4 hybrid forms an unusual soft material core–shell topology with graphenic carbon nitride wrapping around SnIP. A 1D van der Waals heterostructure is formed capable of performing effective water splitting.

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We provide an update on the current state of the tolerance factor concept for hybrid organic–inorganic perovskites, reviewing the different improvements that have been made over the past few years.

A series of new defect-engineered metal−organic frameworks (DEMOFs) were synthesized by framework doping with truncated linkers employing the mixed-linker approach. Two tritopic defective (truncated) linkers, biphenyl-3,3′,5-tricarboxylates (L H ) lacking a ligating group and 5-(5-carboxypyridin-3yl)isophthalates (L Py ) bearing a weaker interacting ligator site, were integrated into the framework of Cu 2 (BPTC) (NOTT-100, BPTC = biphenyl-3,3′,5,5′-tetracarboxylates). Incorporating L H into the framework mainly generates missing metal node defects, thereby obtaining dangling COOH groups in the framework. However, introducing L Py forms more modified metal nodes featuring reduced and more accessible Cu sites. In comparison with the pristine NOTT-100, the defect-engineered NOTT-100 (DE-NOTT-100) samples show two unique features: (i) functional groups (the protonated carboxylate groups as the Brønsted acid sites or the pyridyl N atoms as the Lewis basic sites), which can act as second active sites, are incorporated into the MOF frameworks, and (ii) more modified paddlewheels, which provided extra coordinatively unsaturated sites, are generated. The cooperative functioning of the above characteristics enhances the catalytic performance of certain types of reactions. For a proof of concept, two exemplary reactions, namely, the cycloaddition of CO 2 with propylene oxide to propylene carbonate and the cyclopropanation of styrene, were carried out to evaluate the catalytic activities of those DE-NOTT-100 materials depending on the defect structure.