[en] This invention relates to polyenes containing at least two ethylenically unsaturated bonds per molecule formed by reacting in substantially stoichiometric amounts, (1) a primary diamine, (2) a member of the group consisting of a benzenoid-containing dianhydride, acid anhydride and anhydride acid halide and (3) an ethylenically unsaturated alcohol. The thus formed amide-acid polyene either per se or after being cured in combination with a polythiol in the presence of a free radical generator will, upon heating, imidize. The free radicals, which cause hardening, can be generated by irradiation, for example with ultraviolet light. (Auth.)

[en] Multidetector CT (MDCT, multislice CT, multidetector-row CT, multisection CT) represents a breakthrough in CT technology. It has transformed CT from an transaxial cross-sectional technique into a true 3D imaging modality that allows for arbitrary cut planes as well as excellent 3D displays of the data volume. Multislice CT scanners provide a huge gain in performance that can be used to reduce scan time, to reduce section collimation, or to increase scan length substantially. The following article will provide an overview of the principles of multislice CT scanning. It describes the various detector systems and gives an introduction to the most important acquisition and reconstruction parameters. The article describes how reconstruction of thick multiplanar reformations can be used to take advantage of the 3D capabilities of multislice CT while keep radiation exposure to a minimum

[en] The response of an integrable QFT under variation of the Unruh temperature has recently been shown to be computable from an S-matrix preserving ('replica') deformation of the form factor approach. We show that replica-deformed form factors of the SU(2)-invariant Thirring model can be found among the solutions of the rational sl₂ -type quantum Knizhnik-Zamolodchikov equation at generic level. We show that modulo conserved charge solutions the deformed form factors are in one-to-one correspondence to the ones at level zero and use this to conjecture the deformed form factors of the Noether current in our model

[en] Multislice CT has overcome past limitations of CT angiography (CTA): Scan length and spatial resolution can be simultaneously optimized with multislice CTA, contrast medium can be saved, and the evaluation of large anatomic areas and vessels smaller than 1 mm become possible. This article describes how to optimize scanning protocols and contrast injection, and discusses the main clinical applications of this new technique. Only three main scanning protocolssuffice for all indications. A high speed / high-volume protocol (using 4*2mm or 4*2.5mm collimation) can be employed to scan the chest or abdomen in 8-10s, or to cover the whole abdominal aorta and the peripheral runoff including the feet within 40-65s. A high resolution protocol (using 4*1mm or 4*1.25mm) can be employed for the aorta and most regional vascular beds. It allows for near isotrophic imaging and depicts fine vascular structures with excellent detail. Ultra-high resolution protocols (using 2*0.5mm or 4*0.5mm collimation) yield totally isotropic data sets, and are mainly reserved for cerebrovascular imaging. Image processing techniques, and, in particular, volume rendering have made image presentation faster and easier. Multislice CTA exceeds MRA in spatial resolution and is now able to display even small vascular side branches. Its main indications will be aortic diseases, suspected pulmonary embolism but also renal artery stenoses, preoperative workup of abdominal or cerebral vessels, and acute vascular diseases. Multisplice CTA will become a strong competitor of other minimally invasive vascular imaging techniques

[en] Limiting global warming to well below 2 °C requires the transformation of the global energy system at a scale unprecedented since the industrial revolution. To meet this 2 °C goal, 87% of integrated assessment models opt for using bioenergy with carbon capture and storage (BECCS). Without BECCS, the models predict that the goal will be either unachievable or substantially more costly to meet. While the modeling literature is extensive, studies of how key climate policy actors perceive and prioritize BECCS are sparse. This article provides a unique intercontinental mapping of the prioritization of BECCS for the long term transition of the electricity supply sector. Based on survey responses from 711 UN climate change conference delegates, the article reports the low prioritization of BECCS relative to alternative technologies, indicating an urgent need for studies of the socio-political preconditions for large-scale BECCS deployment. - Highlights: • UN climate conference delegates’ prioritization of BECCS investments is mapped. • The preferences depend on the respondents’ actor type and regional belonging. • State actors are more positive toward BECCS investments than are non-state actors. • Investment preferences correlate with technical potential in respondents’ regions. • The results indicate an urgent need for further studies of the legitimacy of BECCS.

No abstract available

[en] Highlights: • We simulate electron dynamics in polyene and polyyne bridged molecular wires. • Time-dependent configuration interaction method has been employed. • A multireference configuration interaction singles approach is proposed. • We investigate the role of symmetry and localization of the initial state. • Introduction of a sodium cluster at the acceptor end leads to electron trapping. - Abstract: In this study we present methodological developments of the time-dependent configuration interaction (TDCI) method for ab initio electron dynamics in donor–bridge–acceptor systems. Especially, we investigate the role of valence electron correlation, the scheme for selecting the determinantal basis, and the computational effort. Our test systems are molecules of the type Li–(C₂)_n–CN, Li–(C₂H₂)_n–CN, and Na₉–(C₂H₂)₂–CN. In this way, this study is intended as a step towards rigorous description of charge transfer in molecular wires attached to metal surfaces or nanoparticles using a many-electron wavefunction. Also, a multi-reference configuration interaction singles approach is suggested as a good compromise between computational effort and accuracy

[en] We show how discrete torsion can be implemented in D=4, N=1 type IIB orientifolds. Some consistency conditions are found from the closed string and open string spectrum and from tadpole cancellation. Only real values of the discrete torsion parameter are allowed, i.e. epsilon=+-1. Orientifold models are related to real projective representations. In a similar way as complex projective representations are classified by H²(Γ,C*)=H²(Γ,U(1)), real projective representations are characterized by H²(Γ,R*)=H²(Γ,Z₂). Four different types of orientifold constructions are possible. We classify these models and give the spectrum and the tadpole cancellation conditions explicitly. (author)

[en] The influence of the layer architecture on the fatigue properties of ultrafine-grained laminated metal composites is studied. Composites with different stacking sequences of the aluminum alloys AA1050, AA5005, and AA2024 were produced by accumulative roll bonding and characterized by microstructural analysis and nanoindentation experiments. The fatigue properties were determined by 3-point bending tests performed on a vibraphore testing machine. Subsequently, the crack path was analyzed using a scanning electron microscope. It was observed that the fatigue crack bifurcates close to the interface if the hardness difference between both materials is high. The crack then spreads parallel to the interface within the softer material. This crack branching is more pronounced at high stress amplitudes caused by a significant accumulation of plastic deformation in front of the interface. Consequently, at high stress amplitudes the fatigue lives are significantly higher for composites with a high hardness difference between the layers. At low stress amplitudes, at which crack initiation is the dominating fatigue mechanism, the material of the outer layer mainly determines the fatigue lives. Composites with the same outer layer, but different interlayers, show very similar high cycle fatigue lives. Thus, by an appropriate layer architecture ultrafine-grained laminated metal composites with significantly enhanced fatigue properties can be designed.

[en] The fracture toughness of freestanding gold films with thicknesses between 60 nm and 320 nm was determined by bulge testing to be around 2 MPa m^1/2. This surprisingly low value confirms the trend also observed for other metals that thin films exhibit only a fraction of the bulk fracture toughness. In order to understand this behavior, the fracture process of freestanding gold films with a crack introduced by focused ion beam (FIB) milling was observed in-situ in an atomic force microscope (AFM). AFM scans of the crack tip region show stable crack growth mainly along grain boundaries. Plastic deformation is localized in a narrow corridor in front of the crack tip. A large plastic zone, as one would typically expect under plane stress, is not observed. Instead, strong local necking is evidenced. We conclude that the spatial confinement of the plastic deformation is the primary reason for the low fracture toughness of metallic thin films.