Photosensitive systems for microlithography based on organometallic photoinitiators

The photodecomposition of the Ar-laser sensitive photo-initiator bis(pentafluorophenyl)titanocene 1 was investigated. Two intermediate species were postulated: a pentafluorophenylcyclopentenyl radical 16 which acts as quencher and a ketene acetal radical of the structure CH₂-CH=C(OCH₃)OTiR_x 17 which could initiate the polymerization.     

Synthesis of purines and other fused imidazoles from acyclic amidines and guanidines

[reaction: see text] Purines, xanthines, and other fused imidazoles can be prepared from amidines or guanidines, with retrosynthetic disconnection at the ring fusion. Ring closure proceeds using Cu(I), with no special ligands required. The method allows for easy modification of the heterocyclic nucleus and is tolerant of functionality pendant to the ring system.     

Weak fractured solutions in the calculus of variations

Necessary conditions and sufficient conditions for a weak minimum of a variational problem over a class of functions which allow for a finite number of fractures (simple discontinuities) in the dependent variables are derived. Our results extend those of Razmadzé (Ref. 1).     

On the determination of energy fluxes at plasma–surface processes

A summary is given of different methods for the determination of the energy influx and its influence on the thermal balance and energetic conditions of substrate surfaces during plasma processing. The discussed mechanisms include heat radiation and kinetic and potential energy of charged particles and sputtered neutrals. For a few examples such as magnetron sputtering of a-C:H films, sputter deposition of aluminum on microparticles, and titanium deposition in a hollow-cathode arc evaporation device the energetic balance of substrates during plasma processing is presented. Received: 6 July 2000 / Accepted: 12 December 2000 / Published online: 3 April 2001     

Optimal calibration for multiple testing against local inhomogeneity in higher dimension

Based on two independent samples X ₁, . . . , X _m and X _m+1, . . . , X _n drawn from multivariate distributions with unknown Lebesgue densities p and q respectively, we propose an exact multiple test in order to identify simultaneously regions of significant deviations between p and q. The construction is built from randomized nearest-neighbor statistics. It does not require any preliminary information about the multivariate densities such as compact support, strict positivity or smoothness and shape properties. The properly adjusted multiple testing procedure is shown to be sharp-optimal for typical arrangements of the observation values which appear with probability close to one. The proof relies on a new coupling Bernstein type exponential inequality, reflecting the non-subgaussian tail behavior of a combinatorial process. For power investigation of the proposed method a reparametrized minimax set-up is introduced, reducing the composite hypothesis ??p?=?q?? to a simple one with the multivariate mixed density (m/n)p?+?(1 ? m/n)q as infinite dimensional nuisance parameter. Within this framework, the test is shown to be spatially and sharply asymptotically adaptive with respect to uniform loss on isotropic H?lder classes. The exact minimax risk asymptotics are obtained in terms of solutions of the optimal recovery.