Glass‐embedded silver nanoparticle patterns by masked ion‐exchange process for surface‐enhanced Raman scattering

Glass‐embedded silver nanoparticle patterns were fabricated by masked silver–sodium ion‐exchange process followed by etching to reveal the particles for surface‐enhanced Raman scattering (SERS). The intensity of the enhanced Raman signal is comparable to that of the fluorescence, and the detection limit of 1 nM for Rhodamine 6G has been achieved. Raman images at different etching depths and corresponding morphological images are compared to find optimal SERS signal. Our results demonstrate that silver nanoparticle patterns embedded in glass can be used as SERS‐active substrates. Nanoparticles can be formed in a glass of high optical quality and have potential to be integrated with optical waveguides for a sensor chip. Copyright © 2010 John Wiley & Sons, Ltd.     

High resolution resonant Auger spectroscopy of free atoms and molecules

Recent progress in high resolution resonant Auger spectroscopy in the VUV/soft X-ray region is discussed in some detail both from the experimental and theoretical points of view. Some illustrative examples are presented in order to show the progress in the field, emphasized by recent high resolution measurements at “the Finnish beamline”, bl 51, at the MAX I synchrotron radiation facility.     

Inclusion problems in ordered topological vector spaces and applications

In this paper we study the existence of minimal and maximal solutions of inclusion problems in ordered topological vector spaces, and apply the obtained results to operator inclusions in ordered Banach spaces and to differential inclusions.     

Robust controller for systems with exponentially stable strongly continuous semigroups

The theory of robust controllers is extended to the case where we have boundary and/or distributed control and the system operator is an infinitesimal generator of a strongly continuous exponentially stable semigroup. An example on hyperbolic systems is presented.     

Proficiency test on the determination of mineral oil from polluted soils

Mineral oil products are abundant sources of environmental contamination. A Finnishproficiency test was carried out to investigate the quality of data provided in an analysis of mineral oil in polluted soils. The homogeneity and stability of the samples were tested. The calculated concentration or the median value of the results was used as the assigned value because of the unavailability of certified reference materials (CRMs). The samples were analysed using an infrared spectroscopy (IR) or gas chromatography (GC) procedure. Even if the participating laboratories had little experience with GC, the results were promising. Hence, the GC procedure will replace IR as the new ISO standard (ISO/DIS 16703) in the near future in many Finnish environmental laboratories. There is a need for CRMs for the determination of mineral oil using the GC method due to common contamination problems caused by mineral oil. Received: 9 December 2001 Accepted: 14 February 2002     

Oxidation of Some Furanoselenium Compounds

The organoselenium fragmentation under oxidative conditions to form a carbon-carbon double bond under very mild condition is well established.¹ So [2, 3] -sigmatropic rearrangements of allylic selenium species are well-known.     

Linear fractional transformations of Stieltjes functions

Linear fractional transformations of Stieltjes (and inverse Stieljes) functions, which appear naturally in the extension theory of nonnegative symmetric operators with defect one in Hilbert spaces, are investigated. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Existence and multiplicity for quasilinear elliptic inclusions with nonmonotone discontinuous multifunction

We develop a flexible tool in terms of appropriately defined sub- and supersolutions that allows for obtaining existence, bounds, and multiplicity of solutions for quasilinear elliptic inclusions with a discontinuous multi-function that need neither be upper nor lower semicontinuous. The problem under consideration may be used to describe certain free boundary problems in mechanical models involving multi-valued constitutive laws. Our approach is based on a combined use of abstract fixed point results for monotone mappings on partially ordered sets, and on the existence and comparison results for multi-valued quasilinear elliptic problems with Clarke’s generalized gradient.