Multivariate CARMA processes

A multivariate Lévy-driven continuous time autoregressive moving average (CARMA) model of order (p,q$p,q$), q<p$q<p$, is introduced. It extends the well-known univariate CARMA and multivariate discrete time ARMA models. We give an explicit construction using a state space representation and a spectral representation of the driving Lévy process. Furthermore, various probabilistic properties of the state space model and the multivariate CARMA process itself are discussed in detail.     

Modification Pathways for Copoly(2‐oxazoline)s Enabling Their Application as Antireflective Coatings in Photolithography

Chromophore‐functionalized copoly(2‐oxazoline)s are successfully evaluated as bottom antireflective coatings (BARCs) in high‐resolution photolithography. With respect to UV light sources used in photolithographic production routines, anthracene is chosen as a chromophore. For application as polymer in BARCs, the copolymer poly(2‐ethyl‐2‐oxazolin)₄₅‐stat‐poly(2‐dec‐9′‐enyl‐2‐oxazolin)₂₀‐stat‐poly(2‐(3′‐(1″‐(anthracen‐9‐ylmethyl)‐1″,2″,3″‐triazol‐4‐yl)propyl)‐2‐oxazolin)₃₅ can be synthesized by the Huisgen cycloaddition click reaction of the copolymer poly(2‐ethyl‐2‐oxazolin)₄₅‐stat‐poly(2‐dec‐9′‐enyl‐2‐oxazolin)₂₀‐stat‐poly(2‐pent‐4′‐inyl‐2‐oxazolin)₃₅ and the corresponding azide‐functionalized anthracenes. These copolymers can be crosslinked by the thermally induced thiol‐ene reaction involving the unsaturated C=C bonds of the poly(2‐dec‐9′‐enyl‐2‐oxazoline) repetition units and a multifunctional thiol as crosslinker. Tests of this BARC in a clean room under production conditions reveal a significant decrease of the swing‐curve of a chemically amplified positive photoresist by more than 50%, hence significantly increasing the resolution of the photoresist.

     

Structure and rheology of model side-chain liquid crystalline polymers with varying mesogen length

We probed the structural transitions and rheological properties of norbornene-based polymeric liquid crystals with attached side mesogenic groups of varying length. Whereas the short side chain liquid crystals (C5) formed a nematic mesophase, the long ones (C9) formed a smectic-A solid. The degree of polymerization of the main backbone affected the isotropic-mesophase transition temperatures, but did not influence the change of the mesophase dynamics from the isotropic to the anisotropic state. The temperature dependence of the shift factors obtained from the time-temperature superposition were divided into three regions, namely isotropic, mesophase, and transition, all exhibiting Arrhenius behavior except for the nematic fluid, which followed a WLF dependence. A remarkable strain hardening observed in both nematic and smectic samples was attributed to the dynamic coupling of the main chain and the mesogenic side groups. By applying large amplitude oscillatory shear, macroscopic alignment was achieved; the long recovery times upon flow cessation suggested a very slow structural reorganization, which was much longer in the smectics compared to the nematics, possibly due to the involvement of smaller length scales in the former case. Received: 26 December 2000/Accepted: 26 February 2001     

[{ReN(Me2PhP)(Et2dtc)Cl}2{ReN(Et22tc)2}2{SbCl3}2] — ein neuer vierkerniger Rheniumkomplex mit asymmetrischen Nitridobrücken

[{ReN(Me₂PhP)(Et₂dtc)Cl}₂{ReN(Et₂dtc)₂}₂{SbCl₃}₂] — a Novel Tetranuclear Rhenium Complex with Asymmetric Nitrido Bridges The reaction of [ReN(Et₂dtc)₂(Me2₂hP)] (Me₂PhP = dimethylphenylphosphine, Et₂dtc^‐ = diethyldithiocarbamate) with SbCl₃ in dichloromethane results in the formation of [{ReN(Me₂PhP)(Et2₂tc)Cl}₂{ReN(Et₂dtc)₂}₂{SbCl₃}₂]. A {Re≡N‐}₄ ring with asymmetric nitrido bridges is stabilised by the co‐ordination of SbCl₃ onto the chloro ligands and sulphur atoms of the dithiocarbamates. The compound decomposes upon heating in acetonitrile and the fragments of the tetrameric complex re‐arrange to form [ReN‐(Me₂PhP)(Et₂dtc)Cl]₄ and [ReN(Et₂dtc)₂]. The multinuclear rhenium compounds have been studied by X‐ray crystallography. The 8‐membered {Re≡N‐}₄ ring system in [{ReN(Me₂PhP)(Et₂dtc)Cl}2₂ReN(Et₂dtc)₂}₂{SbCl₃}₂] is almost planar, while that of [ReN(Me₂PhP)(Et₂dtc)Cl]₄ is clearly V‐shaped when viewed down either diagonal Re…Re axis. A dihedral angle of 47.88(2)° has been found between the contributing planes.     

Block Copolymers via ROMP – Awakening the Sleeping Beauty

This paper on recent developments in block copolymerisation using ring-opening metathesis polymerisation summarizes about 60 publications and discusses current trends.     

The ATLAS data quality defect database system

The ATLAS experiment at the Large Hadron Collider has implemented a new system for recording information on detector status and data quality, and for transmitting this information to users performing physics analysis. This system revolves around the concept of “defects,” which are well-defined, fine-grained, unambiguous occurrences affecting the quality of recorded data. The motivation, implementation, and operation of this system is described.     

Ueber die Bestimmung des Cadmiums

Ohne Zusammenfassung     

Reaction of 3-(N-phenylamino)-1-p-tolylprop-2-en-1-one with Ru3(CO)12

Russian Chemical Bulletin -