Probabilistische Modellierung hochfester Stahlbetonstützen in Hochhäusern

Probabilistic Modelling of HPC Slender Columns in High‐Rise Buildings In Germany high strength concrete is used successfully since 1990. The extremely high compressive strength of this material allows considerable reduction in cross‐sectional dimensions of reinforced concrete columns and accordingly accomplishes highest architectural and functional requirements. This leads in many cases to extremely slender structures and therefore increases the risk of failure due to loss of stability. Because of the positive experience with high strength concrete up to now, the current study questions the initial conservative design provisions. In this context code procedures of DIN 1055‐3 and DIN 1045‐1 are compared with the results of probabilistic analysis and potential optimization will be indicated.     

HF-unterstützte Synthese von Orthoestern und Oxazolinen. [1]

A convenient method is reported to generate the ortho-pivalic acid esters 5 and 7 from meso-erythrit 3 ) and D -mannitol ( 6 ), respectively, using a HF-supported procedure. Furthermore, the α-D -glucopyrano[1,2-d]-2-oxazolines 9 and 10 were prepared from starch and nitriles (pivalonitrile and benzonitrile) by a Ritter-type reaction in anhydrous hydrogen fluoride. The separation of the products 5 , 7 , 9 , and 10 was possible by quenching of their HF-solutions with triethylamine. The structure of the orthoester 7 and the oxazoline 10 was confirmed by X-ray analyses.     

Wechselwirkungen in Kristallen. 136. Protonierte Di(pyrid-2-yl)amin-Salze mit verschiedenen Anionen: Monomeres Tetraphenylborat sowie Bis(trifluormethylsulfonat), dimeres Squarat und polymeres Chlorid-Dihydrat

Interactions in Crystals. 136. Protonated Dipyridylamine Salts with Different Anions: Monomeric Tetraphenylborate as well as Bis(trifluormethylsulfonate), Dimeric Squarate and Polymeric Chloride Dihydrate Di(pyrid-2-yl)amine is monoprotonated by acetic, squaric as well as hydrochloric acid and diprotonated by trifluoromethylsulfonic acid. To explore the anion and hydrogen-bridge dependency of its salts, crystals of the monomeric tetraphenylborate, the dimeric squarate as well as the bis(trifluoromethylsulfonate) and the polymeric chloride hydrate have been grown and their structures determined: Separated by bulky tetraphenylborate anions, pyrid-2-yl(2′-pyridinium) amine cation contains an intramolecular hydrogen bridge N^⊕H…︁N and is slightly folded. The squarate salt dimer exhibits additional bridges, N H…︁O^⊖ and O H…︁O. The severely twisted di(2-pyridinium)amine dication is connected to its trifluormethylsulfonate counter anions by altogether three H-bridges, two N^⊕H…︁O and one N H…︁O. The chloride dihydrate crystallizes in layers of 16-membered rings, formed from three Cl anions and five water molecules. The diversity of the hydrogen-bridge dominated salt structures is discussed based on comparison with selected literature examples and on PM3 calculations.     

Thermoplastic cellulose acetate and cellulose acetate compounds prepared by reactive processing

Novel families of thermoplastic polysaccharides such as cellulose-2,5-acetate were produced by means of reactive processing technology that grafted cyclic lactones simultaneously onto polysaccharide, hydroxyfunctional plasticizer, and optionally also onto hydroxyfunctional fillers. Organosolv lignin, cellulose, starch, and chitin were added to effect reinforcement of the polymer matrix. Mechanical and thermal properties depended upon molecular architecture of the components and process parameters such as temperature, feed ratios, and screw speed. Such blends and composites utilize renewable resources and are of interest in waste disposal via biodegradation. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 213–242, 1997     

Freestanding 3D Supramolecular Particle Bridges: Fabrication and Mechanical Behavior

Freestanding particle bridges with controlled composition and macroscopic robustness are demonstrated by the use of supramolecular nanoparticle assembly. Self‐assembly of nanoparticles, templating, and supramolecular glue infiltration are combined to form stable and ordered three‐dimensional polystyrene particle composites on a polydimethylsiloxane stamp. Freestanding hybrid polystyrene nanoparticle bridges are obtained by transfer printing of the hybrid structures onto topographically patterned substrates via host–guest interactions. The mechanical robustness and rigidity of the particle bridges can be controlled by manipulating the layer‐by‐layer cycles of supramolecular glues of gold nanoparticles and dendrimers. Atomic force microscopy‐based microbending results, in particular the location and force‐dependent deflection behavior, confirm that the particle bridge fulfills the classical supported‐beam characteristics. As estimated from classical beam theory, the bending moduli of the particle bridges vary between 0.8 and 1.1 GPa, depending on the degree of filling by the supramolecular glues. Failure analysis on the particle structure indicates linear elastic behavior and a plastic deformation upon failure.     

掩模材料与新颖的衬底方案关键问题及新的良机

通过对掩模衬底材料和掩模加工工艺利用硬性分界条件可满足45nm及以下技术节点的掩模要求。此外类似于折射指数、平整度、成分、均匀性和应力等衬底材料的固有特性严重地影响到掩模加工性能和光刻性能。评述了45nm及以下技术节点对空白材料,掩模及晶片层面的要求。指出了对于关键问题及出现的问题的可仿效实施的方法,最后研究了集成用于高效光掩模工厂的掩模材料的实际情况分析。