Informing Spectroscopists for Over 40 Years

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Displaying 221–240 of 245 results

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Steve Down

HD Science Limited, 16 Petworth Avenue, Toton, Nottingham NG9 6JF, UK

Peter Wilhelm,a Boril Chernev,a Peter Pölt,a Gerald Kothleitner,a Klaus-Jochen Eichhorn,b Gisela Pompe,b Nikola Johnerc and Alexander Piryc

aResearch Institute for Electron Microscopy, Graz University of Technology; Steyrergasse 17, A-8010 Graz, Austria. E-mail: peter.wilhelm@tugraz.at
bInstitute of Polymer Research Dresden; Hohe Straße 6, D-01069 Dresden, Germany

Robert H.H. van den Heuvel* and Albert J.R. Heck

Department of Biomolecular Mass Spectrometry, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, The Netherlands

The goal of building a multivariate calibration model is to predict a chemical or physical property from a set of predictor variables, e.g. analyte concentration or octane number from a near infrared (NIR) spectrum. A good multivariate calibration model should be able to replace the laborious, possibly imprecise reference method. The quality of a model therefore primarily depends on its predictive ability. Other properties such as interpretability of the model coefficients might also be of interest, but here the focus is on the problem of quantifying the predictive ability.

Issue 16/1 (2004)

Gabriel Pinto and Isabel Paz

Departamento de Ingeniería Química Industrial y del Medio Ambiente, E.T.S.I. Industriales, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, 28006 Madrid, Spain

Paul Dumas

LURE, centre Universitaire Paris Sud, BP 34, F-91898 Orsay Cédex, France

Mark J. Tobin

CCLRC Daresbury Laboratories, Warrington, Cheshire WA4 4AD, UK

Philippe Colomban

LA​DIR-UMR 7075 CNRS & Université P. & M. Curie, 2 rue Henry Dunant, 94320 Thiais, France

G.J. Price, G.W. Fraser, J.F. Pearson, I.B. Hutchinson, A.D. Holland, J. Nussey, D. Vernon, D. Pullan and K. Turner

Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK. E-mail: gwf@star.le.ac.uk

E.A.H. Timmermans and J.J.A.M. van der Mullen*

Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands. E-mail address j.j.a.m.v.d.mullen@tue.nl

T. Wirtz and H.-N. Migeon

Laboratoire d’Analyse des Matériaux, Centre de Recherche Public - Gabriel Lippmann, 162A, av. de la Faïencerie, L-1511 Luxembourg, wirtzt@crpgl.lu

David Chenery and Hannah Bowring

Smith & Nephew Group Research Centre, York Science Park, Heslington, York YO10 5DF, UK

 

Introduction

Glow Discharge Mass Spectrometry (GDMS) is one of the most powerful solid state analytical methods for the direct determination of traces, impurities and depth profiling of solids.1–5 Glow discharge mass spectrometers, which are commercially available with fast and sensitive electrical ion detection, allow direct trace elemental determination in solid materials with good sensitivity and precision in the concentration range lower than ng g–1.6

Issue 15/3 (2003)

Luisa Mannina,a,b Anatoli P. Sobolevb and Annalaura Segreb

aUniversity of Molise, Faculty of Agriculture, 86100 Campobasso, Italy
bInstitute of Chemical Methodologies, CNR, 00016 Monterotondo Staz., Rome, Italy

Issue 15/3 (2003)

Moore’s law* dictates microelectronics researchers to make integrated circuit (IC) devices smaller and to put them as close to each other as possible on a chip. This results in a better performance and a larger functionality of the chips. However, these devices also require a good electrical isolation from each other. This is in general done by the formation of a thick local oxide in the “field region” between the devices. In 1970, researchers from Philips1 invented the so-called LOCOS (LOCal Oxidation of Silicon) technique to achieve this isolation. Using a Si3N4 mask, the silicon is thermally oxidised in the nitride-free field regions. Figure 1 (left) shows a typical LOCOS structure. Although LOCOS seemed a perfect solution at that time, it came with a lot of problems, many of them related to mechanical stresses. Thermal oxidation of Si to SiO2 occurs together with a 125% volume expansion. As a result, the oxide grown in the field region, called the “field oxide,” exerts large forces on the surrounding silicon. Another major drawback of this technique is the so-called “bird’s beak,” caused by the lateral growth of the oxide under the nitride mask. This bird’s beak not only affects the intended device length, it also introduces large local mechanical stresses in the silicon, because of volume expansion, and it also deforms the nitride film. These stresses often resulted in the generation of dislocations in the silicon, which are quite harmful for the devices.

Issue 15/2 (2003)

S.Y. Luk,a N. Patela and M.C. Daviesb

aMolecular Profiles Ltd, 1 Faraday Building, Nottingham Science & Technology Park, University Boulevard, Nottingham NG7 2QP, UK. E-mail: sluk@molprofiles.co.uk
bLaboratory of Biophysics and Surface Analysis, School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK

Alan Street

Technical Director, Oxford Instruments Superconductivity

Dipl. Chem. FH Ch. Schanzer and Prof. Dr H.G. Bührer

Department of Chemistry, Zurich University of Applied Sciences Winterthur (ZHW), CH-8401 Winterthur, Switzerland

S.E.J. Bell,a* E.S.O. Bourguignon,a A. O’Grady,a J. Villaumiea and A.C. Dennisb

aSchool of Chemistry, The Queen’s University of Belfast, Belfast, BT9 5AG, Northern Ireland, UK
bAvalon Instruments Ltd, 10 Malone Road, Belfast BT9 5BN, Northern Ireland, UK

J. Sabine Becker

Central Department of Analytical Chemistry, Research Centre Jülich, D-52425 Jülich, Germany

Issue 14/6 (2002)

Luis Oliveira and Manuel Pais Clemente

CETO – Centro de Ciências e Tecnologias Ópticas, Rua Caldas Xavier, Nº38, 6º E, 4150 Porto, Portugal. E-mail: ceto@google.pt

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