bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of hydrocarbon remediation (diesel oil and polycyclic aromatic hydrocarbons) on enzyme activities and microbial properties of soil
Authors: Margesin R. , Walder G. , Schinner F.
Published: December 2004

The impact of hydrocarbon remediation on several enzyme activities (catalase, dehydrogenase, lipase, protease, urease, alkaline phosphomonoesterase, fluorescein diacetate hydrolysis) and microbial properties (biomass‐C, respiration, N‐mineralization,qCO2, microbial counts) was evaluated in a laboratory study over a period of 10 weeks. A pristine soil was contaminated with diesel oil (10 mg/g soil) or with a mixture of phenanthrene and naphthalene (total amount 1 mg/g soil) and supplemented with inorganic nutrients to give a C:N ratio of 20:1. The corresponding controls consisted of uncontaminated nutrient‐supplemented soil. Oil contamination caused a significant initial increase of all biological parameters measured. In the presence of PAHs, biomass‐C, respiration, protease activity and heterotrophic counts were significantly enhanced, while urease activity was depressed. N‐mineralization was initially, however, reversibly inhibited in the presence of oil and PAHs.

The measured parameters behaved differently over time: Biomass‐C, respiration and alkaline phosphomonoesterase activity reached a maximum activity after about 2–5 weeks, corresponding to the period during which the majority of hydrocarbons disappeared, and declined thereafter to the background level. Activities of catalase and dehydrogenase also followed this pattern, however, were characterized by fluctuations. Activities of lipase, protease, urease and fluorescein diacetate hydrolysis increased and remained almost constant throughout the incubation period.
Magneto‐Optical Recording and Data Storage Materials
Authors: Greidanus Frans J. A. M. , Klahn Stefan
Published: December 2004

Amorphous rare‐earth (RE) transition‐mental (TM) alloys are used for magneto‐optical (MO) recording a rapidly developing technology, which combines the possibility of achieving high bit densities with practically unlimited erasability and rewritability. During the last years new insights, relating material properties to recording performance, have been obtained. New experimental techniques, such as the observation of magnetic contrast in the electron microscope, have made a major contribution to the understanding of domain formation processes. The RE‐TM alloys have been most successful in recording applications until now. In these materials the RE‐TM composition determines both the compensation and Curie temperatures and has a strong impact on the recording characteristics. Improvements in deposition techniques and the application of dielectric layers resulted in carrier‐to‐noise ratios of 61 dB. Despite major improvements, problems related to corrosion and structural relaxtion, which lead to long‐term instabilities, have not yet been solved completely. Another important topic is the so‐called direct‐overwrite problem, which will be discussed in relation to the material properties.
The Keviar Story—an Advanced Materials Case Study
Authors: Tanner David , Fitzgerald James A. , Phillips Brian R.
Published: December 2004

Limited space permits description of only two examples of Kevlar applications research. There are numerous others. In the early product development there were some indications that Kevlar would go mainly into tire reinforcement. This has turned out not to be true. In the mid‐seventies Kevlar was participating in only ten market segments and less than fifty specific applications, but today, it is in more than twenty market segments, serving more than two hundred applications, and continued growth is anticipated. Kevlar is produced in a 45 million pound plant in Richmond, VA, USA. In 1988, a second plant was started up in Northern Ireland and plans for a third plant in Japan were announced. The Kevlar innovation story exemplifies the kind of obstacles, interdisciplinary skills and systems approach involved in bringing a laboratory discovery to commercial reality. The story is still unfolding and applications currently not envisioned will undoubtedly become important in the future. magnified image.
Challenges in Materials for Health Care Applications
Authors: Williams David F.
Published: December 2004

Important issues face the use of advanced materials in medical applications. It is now possible to replace or augment many tissues and parts of the body by implanted devices, but there are still severe limitations to functions they are able to perform and problems associated with their compatibility with the tissues. Biomaterials of the future need to simulate more closely the tissues they are replacing and both the current position and future outlook are reviewed in this light.
Magnetic recording media in Rimini
Authors: Luitjens Steven
Published: December 2004

Stevens Luitjens of Philips reports on a meeting in Italy on magnetic recording media, and Peter Andrekson and Per Andersson survey proceedings at a conference on optical communication recently held in Sweden.
Aurivillius phases: Non‐superconducting materials?
Authors: Zhou Wuzong
Published: December 2004

Are aurivillius phases a new class of metal oxide superconductor? Recent reports in theliterature suggest that they are but this new study of these two‐layered structures, such as Bi2WO6 (see figure) which contains fluorite‐like Bi2O2 layers sandwiched by WO4 perovskite slabs, indicates that this is perhaps not the case. Electron microscopy and electron diffraction are used to probe these and related phases.

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Chemistry and ceramics in albuquerque
Authors: Kodas Toivo
Published: December 2004

Toivo Kodas describes proceedings at a recent meeeting on chemistry and ceramics held in New Mexico and Hans Riegler reports on his visit to a conference on colloids and interface science in West Germany.
Polymers with Ionic Conductivity
Authors: Armand Michel
Published: December 2004

A solvation‐desolvation mechanism (see figure) is responsible for ionic conductivity in polymers such as polyethylene oxide. The solvating sites are covalently linked through flexible bonds meaning that a net displacement of the ligand with the ions over macroscopic distances is forbidden, a situation intermediate between liquids and solids. Sensors, batteries, and displays are among the applications of these polymeric electrolytes.

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Bulk superconductivity up to 60 K in the In‐Pb‐Ca‐Y‐Sr‐Cu‐O system
Authors: Liu Ru‐Shi , Edwards Peter P. , Wu Ping‐Tien
Published: December 2004

A new high‐Tc superconducting material based on the title system has been synthesized at one atmosphere of oxygen. X‐ray powder diffraction as well as energy dispersive spectrometric analyses shwo a phase with the chemical composition (In0.05PB0.70Cu0.25) (Ca0.05Y0.05)Sr2Cu2Oy, which is isostructural with TlCaBa2Cu2O7, to be responsible for the superconductivity.
Too many peas in the pod?
Authors: Gregory Peter
Published: December 2004

This issue contains much information concerning journals and books in materials science (see “Materials Forum” and “Book Reviews”). The everrising flood of publications puts readers, subscribers and librarians under increasing pressure. The pros and cons of the fast development of publications are discussed.
Ceramics from organometallic polymers
Authors: Peuckert Marcell , Vaahs Tilo , Brück Martin
Published: December 2004

Materials science, an interdisciplinary field of R & D, certainly benefits from the cooperation of engineers, chemists and physicists. An example is in the synthesis and applications development of organometallic polymers. Their structures are being optimized through employing different monomers, polymer blending, and post‐treatments to render them suitable as precursors for non‐oxide advanced ceramics like SiC, Si3N4, AIN, BN or TiN. Pyrolysis transforms these polymers into the ceramic state. Since these inorganic polymers have unique processing advantages (solubility and fusibility) over classical ceramic powder or metallurgical processing, a vast array of novel applications, e.g., ceramic coatings, binders, impregnations or spun fibers are possible.
Photoreactive polymers for electronics
Authors: Rubner Roland
Published: December 2004

Light‐induced changes of the properties of materials are of major imprtance in electronics. This will be illustrated by examples showing the photoresists presently used to produce submicron structures, phot‐patternable insulating materials, and UV‐curable reactive resins.
Piezoelectric Ceramics
Authors: Thomann Helmut
Published: December 2004

Surface acoustic wave filters and delay lines are two application in electronics of piezoelectric ceramics such as LiNbO3 LiTaO3 and BaTiO3, materials which convert a mechanical stimulus into an electrical signal. The basic physics and crystal chemistry of the materials, including ferroelectric ceramics, are described and an outline for further development given.
Synthesis and properties of carboxy‐functionalized poly(3‐alkylthienylenes)
Authors: Bäuerle Peter , Gaudl Kai‐Uwe , Würthner Frank , Sariciftci N. Serdar , Mehring Michael , Neugebauer Helmut , Zhong Chuanjian , Doblhofer Karl
Published: December 2004

The synthesis of a new type of, and doping mechanism in, “self exchange” or “self‐doping” conducting polymers based on 3‐(ω‐carboxyalkyl)thiophenes (with n = 4‐14) is examined (see figure). The properties of the polymers are different to that of those based on the corresponding sulphonic acids due to the lower acidity of the carboxylic acid function.

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Concerted European action on magnets
Authors: Cahn Robert W.
Published: December 2004

Support from brusselshas enabled concerted action in the research and development of magnetic materials as part of the CEAM programme (see logo). The history of this international cooperation, its successes, and future directions are assessed.

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Ion Beam Modified Polyimide
Authors: Davenas Joël , Boiteux Gisèle
Published: December 2004

Altough no polymers are intrinsic conductors, conjugated polymers have been shown to become conducting when heavily doped. However, advances are still needed to achieve both the high stability and conductivity required in most applications. Photon, plasma and ion beam processing of organic materials offer opportunities to induce new properties (e.g. insulating or conducting) in organic precursors. Plasma treatments have led to the remarkable development of diamond‐like film synthesis. This contribution is a review of the recent advances in ion bea modified polyimides, a new variety of high‐performance conducting polymers. Related effects like metal‐adhesion enhancement will also be discussed.
Carbon Fibers
Authors: Ruland Wilhelm
Published: December 2004

High stiffness and strength combiend with low weight are the advantages offered by carbon fibers in the manufacture of reinforced composites. Effective use of these materials depends on an understanding of structure–property relationships One method of help in this work in small angle X‐ray scattering (SAXS), where the intensity distributions (see figure) can be used to determine orientation, shape, size and volume fraction of structural features resulting from different processing temperatures.

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Pleochroism of evaporated metal islands on langmuir–blodgett films
Authors: Bubeck Christoph
Published: December 2004

The structures of molecular monolayers and films can be elucidated by studying the unique linear and nonlinear optical properties of small metal islands deposited on the films. The islands can lead to surface‐enhanced electromagnetic effects as their size and separation are much smaller than the wavelength of light, and these effects have been studied using spectrophotometry and optical microscopy.
Magnetic force microscopy
Authors: Hartmann Uwe
Published: December 2004

Sensitive mapping of near‐surface microfields produced by ferromagnetic media is possible with a spacial resolution under 100 nm using magnetic force microscopy (MFM), a technique related to atomic force microscopy. The method is described and the development of a novel type of MFM microprobe tip (see figure) is also reported.

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Self‐assembled monolayers of alkyltrichiorosilanes: Building blocks for future organic materials
Authors: Ulman Abraham
Published: December 2004

Optoelectronics and molecular electronics are two areas of potential application for monolayers of ordered organic materials. These layers from spontaneously on the immersion of an appropriate substrate into a solution of an active surfactant in an organic solvent. Very strong molecule–substrate interactions result, for example between the organo‐siloxane trimer and a hydroxylated surface (see figure). The build up of mono and multilayers, the nature of the interface interactions and the applications of these organized structures are discussed.

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Ultrathin layers: Innovation through research
Authors: Wegner Gerhard
Published: December 2004

Essay: Wetting, adhesion, biocompatibility, membrane‐ and sensor applications, lubrication, corrosion resistance, and microlithography are all effects which can be strongly influenced by the molecular architecture of the organic solids involved. The synthetic methods employed and the analytical tools that have been developed for the study of these systems have formed the basis of an interdisciplinary project funded jointly by the German Ministry for Research and Technology (BMFT) and Industry. The basis of the project and its aims are introduced and the following articles describe the most recent progress made.
Structural Characterization of Monolayers at the air–water interface
Authors: Möbius Dietmar , Möhwald Helmuth
Published: December 2004

Review: X‐Ray diffraction, fluorescence microscopy, and reflection spectroscopy, are all methods used for the characterization of organic thin films which enable the study of, for example, dipole layers, domain structures, mechanical surface excitations, and the orientation of the hydrocarbon ‘tails’. The methods and their applications, especially in the optimization of monolayer formation and transfer, are reviewed.
Thermostability of polymeric langmuir–blodgett films
Authors: Tippmann‐Krayer Petra , Riegler Hans , Paudler Michaela , Möhwald Helmuth , Siegmund Hans‐Ulrich , Eickmans Johannes , Scheunemann Ude , Licht Ulrike , Schrepp Wolfgang
Published: December 2004

Communication: LB films stable against desorption up to 250°C have been produced from prepolymerized polyurethanes, polyimides and polyamic acid and studied using optical reflection, microscopy, ellipsometry, ESCA, FT‐IR and small angle X‐ray scattering (SAXS). Due to their stability, the materials could be used to prepare multilayer films or as matrices for dyes opening up applications in optics.
Mesophase formed by diabolo‐like molecules
Authors: Malthête Jacques , Levelut Anne‐Marie
Published: December 2004

Communciation: Mesogenic disc‐like compounds possessing a high permanent electric dipole moment are of interest as they offer the possibility of orientating columnar mesophases. The structure (schematically shown in the figure) which is similar to the well‐known toy “Diabolo”, and phase behavior of only the second example of such a compound are described.

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Conducting polymer composites of poly(N‐methylpyrrole) and poly(bisphenol‐A‐carbonate)
Authors: Geißler Uwe , Hallensleben Manfred L. , Toppare Levent
Published: December 2004

Communication: The role of hydrogen bonding in the formation of homogeneous blends of conducting (polypyrrole) and insulating (poly(bisphenol‐A‐carbonate)) polymers is examined. The blends exhibit improved mechanical properties over the brittle pure conducting polymers and it has been suggested that the hydrogen bonding arises from the interaction of carbonyl groups in the insulating polymer and NH groups in the polypyrrole. To test this hypothesis, N‐methylpyrrole, which is incapable of hydrogen bonding, is used in the blends and the resulting materials studied.
Chemical valves and gel actuators
Authors: Osada Yoshihito
Published: December 2004

Research News: Chemomechanical systems, based on porous polymers which undergo shape change or develop contractile forces in response to an external stimulus are attracting much interest as adjustable size‐selective permeation membranes for separating solute mixtures with different molecular size, in controlled drug release, or in actuators such as the gel looper shown in the figure which can move at a speed of 15 mm/min.

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Dynamic observations of relaxation processes in semiconductor heterostructures
Authors: Hull Robert , Bean John C.
Published: December 2004

Review: Strained layer epitaxy, a technique used in the growth of single‐crystal semiconductor heterostructures in which ultrathin layers of semiconductors with differing lattice parameters are grown on top of each other, is well suited for the production of high‐speed electronic devices. The lattice mismatch causes the accumulation of elastic strain energy which is reduced by the inclusion of defects, such as misfit dislocations. The direct and real‐time study of the formation and propagation of these defects using an electron microscope helps us to understand the fundamental processes governing relaxation in heterostructures and is the topic of this review.
A novel combustion synthesis of spinel ferrites, orthoferrites and garnets
Authors: Suresh K. , Kumar N. R. S. , Patil K. C.
Published: December 2004

Communication: Transformer cores and read‐write heads are two applications of micronsized ferrite powders. The powders (see figure) can be synthesized by the thermal decomposition of precursors in a solid solution, where, generally, atmospheric oxygen can be thought of as the oxidant. However, due to the low yields (∼15%) of these processes an alternative has been developed based on the exothermicity of the redox reaction between metal nitrates (oxidants) and tetraformal trisazine or oxalic acid dihydrazide (fuels).

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The STM: A synthetic tool to create ‘molecular wires’?
Authors: Wegner Gerhard
Published: December 2004

Research News/Talking Point: A somewhat less optimistic view is given of the potential uses of the STM in a comment on the ideas presented by A. Alberts in the preceeding article of this issue. The progress made with the STM technique and its limitations are discussed.
Thermal stability of Langmuir‐Blodgett and self‐assembled films: A possible scenario for order–disorder transitions
Authors: Ulman Abraham
Published: December 2004

Review: The effective design of stable, ordered organic superlattices is assisted by a thorough understanding of enthalpy and entropy contributions and molecular interactions in two dimensions. Important information in this respect can be obtained by studying the thermal stability of monolayers of long‐chain organic amphiphiles. Work on both LB and SA films is reviewed and a possible explanation for thermally‐induced structural events (e.g. order–disorder transitions, see figure) in molecular assemblies discussed.

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Optical Applications of Bacteriorhodopsin and its mutated variants
Authors: Bräuchle Christoph , Hampp Norbert , Oesterhelt Dieter
Published: December 2004

Review: Biological systems can be engineered to perform optical data storage. These natural materials, for example bacteriorhodopsin, a protein from the photosynthetic system of a bacteria which lives in exteme environments, can also be employed in pattern recognition (see Figure) where a 25 letter pattern is compared with the letter “P”. The position of the letter “P” in the grid is correctly identified but the letters “B” and “R” are also marked as containing the elements of the letter “P”. This ability to recognize similarity could have important applications in data processing.

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Orientation of monolayers by convection
Authors: Kurthen Christof , Nitsch Walter
Published: December 2004

Communication: Stationary channel flow is shown to generate molecular orientation in a stagnant monolayer perpendicular to that caused by the flow orientation of molecules in solution. The use of a stagnation barrier (see Figure) in a channel flow setup enables the control of the large‐scale in‐plane orientation of dye molecules mixed with rod‐like polymers. The orientation is maintained during Langmuir–Blodgett film transfer.

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“Biomimetic” materials: A potential distortion of materials policies
Authors: Roy Rustum
Published: December 2004

Talking Point: As funding for research becomes ever harder to come by, scientists are increasingly forced to emphasize the importance of their work in terms of potential applications. As a result the question has arisen as to whether some researchers are “overselling” their work. In recent articles in Nature and elsewhere this question has caused a heated debate. In this and the following article two viewpoints in this controversy are presented.
Togetherness
Authors: Cahn Robert
Published: December 2004

Essay: International and inter‐lab cooperation in materials science is examined based on a study of the author affiliations on journal articles and MRS symposium papers. Some papers in physics are attributed to more than 200 authors. The reasons behind these development including the possible influence of central European funding, are discussed.
Synthetic routes to high surface area non‐oxide materials
Authors: Chorley Richard W. , Lednor Peter W.
Published: December 2004

Review: Non‐oxide ceramic compositions, such as carbides, nitrides, borides, and sulfides, in their compacted forms show outstanding mechanical strength and resistance to wear. These properties depend a defect‐free microstructure which can best be obtained through the use of homogeneous, high surface area powdered starting materials. The methods of preparing such powders, and also their use in other applications, such as catalysis, are reviewed.
Langmuir–Blodgett membranes for separation and sensing
Authors: Tieke Bernd
Published: December 2004

The current status of Langmuir–Blodgett (LB) films is described with regard to biomimetic applications as separating membranes and sensor layers. In the first part, recent research activities on the utility of LB membranes for gas separation, liquid permeation, hyper‐ and ultrafiltration are reviewed. The morphological aspects of materials separation in LB films are discussed. In the second part, recent progress in the rapidly growing field of LB‐film‐based chemical sensors and blosensors is reviewed. The structure and function of gas and ion sensors, and enzyme and immunosensors is briefly discussed. Perspectives for future activities in the fields of LB membranes and sensors are outlined.
Magnetically induced super resolution in a magneto‐optical disk
Authors: Kaneko Masahiko , Aratani Katsuhisa , Ohta Masumi
Published: December 2004

Research News: A tenfold increase in the storage densityof magneto‐optical media could be achieved through combining the use of a short wavelength laser and the application of a new detection technique known as magnetically induced super resolution. The effective spot size of the readout laser is reduced by passing the light through a magnetically induced mask (see figure) meaning that the information can be stored closer together on the disk.

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Sol—Gel Processes II Investigation and Application
Authors: Reuter Hans
Published: December 2004

Research News: The production of tailor‐made ceramic materials using the solgel technique is discussed with reference to the chemistry of the starting alkoxides. In the second part of this article a view is also taken of the future requirements for applying the technique to commercial production.
Realization of a blue‐light‐emitting device using poly(p‐phenylene)
Authors: Grem Gabriele , Leditzky Günther , Ullrich Bruno , Leising Günther
Published: December 2004

Blue light emission from poly(p‐phenylene), PPP, at room temperature is reported. Thin films of the polymer have been incorporated into an electroluminescent device (see figure) which constitutes the first polymer‐based blue‐light‐emitting diode (LED), a significant step towards, for example, the development of full‐color LED computer screens. The polymer LED has advantages of stability over its low‐molecular‐weight anologues and ease of fabrication over inorganic semiconductor‐based devices.

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Silicon micro‐velcro
Authors: Reed Michael L. , Han Hongtao , Weiss Lee E.
Published: December 2004

Silicon micromachining technology has been employed to fabricate dense, regular arrays of microstructures which act as mechanical adhesives. Structures such as that shown in the figure have potential applications in the biocompatible bonding of human tissue during surgery, their barb‐like nature preventing retraction. A second approach, using mating structures, provides precision self‐alligning, room‐temperature bonding with potential in the mounting of integrated circuit chips.

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Nanochemistry: Synthesis in diminishing dimensions
Authors: Ozin Geoffrey A.
Published: December 2004

Atomic and molecular size devices are the ultimate goal of those working on, for example, nanoscale patterning and templating techniques. The various approaches to nanophase materials with stringent requirements of size, shape, and dimensionality are discussed, recent highlights are described, and teh advantages to be gained by working on this scale with zeolites (see figure), LB films, fullerenes, organic polymer hosts, semiconductor clusters, porous silicon, STM technology and much more are reviewed.

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Deposition of thin films of Zirconium and Hafnium Boride by plasma enhanced chemical vapor deposition
Authors: Reich Silvia , Suhr Harald , Hankó Klára , Szepes László
Published: December 2004

The technological importance of metal borides is based on their extreme ardness, high melting points, high conductivity, and chemical inertness and durability. The borohydrides of zirconium and hafnium are shown to be excellent precursors for the deposition of boride thin films, their volatility enabling fast deposition rates to be obtained. The high hardness of the boronrich, plasma CVD deposited films makes them ideal for applications as wear‐protective coatings.
Induction of mesogenicity in polymeric hydrogen‐bonded complexes containing heterocyclic‐N‐Oxide
Authors: Kumar Uday , Fréchet M. J.
Published: December 2004

Thermotropic polymers containing charge‐bearing mesogenic moieties in the repeat unit are rare. This article reports a self‐assembly, two‐component approach for the preparation of side‐chain liquid‐crystalline polymeric materials possessing charged hydrogen‐bonded mesogenic groups. A unique feature of this system is that simple mixing of two non‐mesogenic components (see figure) is used to produce a side‐chain liquid‐crystalline polymer.

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Glass‐ceramics with unusual electrical properties
Authors: Partridge Graham
Published: December 2004

Cermaics and glass‐ceramicsare principally known in industry for their good electrical insulation properties. However, some glass‐ceramics exhibit other unusual electrical characteristics. The suitability of the various routes for producing glass‐ceramics with specific properteis for particular applications are discussed. These include piezoelectric and pyroelectric materials, high‐dielectric‐constant materials for use in capacitors, materials whose dielectric constant varies with temperature, electro‐optic materials, and superconductors.
Diagnostics and modeling of silane and methane Plasma CVD Processes
Authors: Davies Paul B. , Martineau Philip M.
Published: December 2004

The deposition of hydrogenated amorphous silicon and diamond can be achieved using plasma‐enhanced chemical vapor deposition. In order to optimize the deposition process and thus the property profiles of the materials obtained it is important that the gas‐phase and surface reactions are understood. The modeling methods and the diagnostic techniques used to follow the processes involved are reviewed and the plasma chemistry of diamond and amorphous silicon deposition compared.
Electric‐field‐induced room‐temperature doping in CuInSe2
Authors: Jakubowicz Abram , Dagan Geula , Schmitz Claus , Cahen David
Published: December 2004

The electric‐field‐induced doping of semiconductors to form permanently‐doped, stable device structures using strong electric fields at room temperature is reported. The figure is a secondary electron image of two gold electrodes contacting the surface of the CuInSe2 sample. Electric‐field application has resulted in the contact becoming ohmic (superimposed trace) indicating that an internal doping profile has been created.

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Synthesis of unsymmetrical biaryls via low‐coordination palladium species
Authors: Gervat Sophie , Léonel Eric , Barraud Jean‐Yves , Ratovelomanana Victorin
Published: December 2004

The biaryl unit is a fundamental feature of a large number of nonlinear optical materials and liquid crystals. Unsymmetrical biaryls (see figure) have been shown to be of particular interest, exhibiting amongst other things a high electro‐optic coefficient. The synthesis of the new unsymmetrical biaryls involves the palladium‐complexcatalyzed coupling of an organometallic derivative with an aromatic halide.

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Elctroluminescence: A bright future for conjugated polymers?
Authors: Bradley Donal D. C.
Published: December 2004

Conjugated polymer electroluminescence has recently been attracting a great deal of attention. The color range achievable now spans red, gree, and blue, and it has also been shown that polymer‐based light‐emitting diodes can be formed as flexible structures. Progress made in the synthesis of the polymers, the patterning of thin films of the polymers for application in large‐area displays, the improvement of device efficiencies, and teh identification of the charge carriers involved is discussed.
The European Physical Society
Authors: Jacob Maurice
Published: December 2004

The President of the European Physical Society describes the structure and activities of the EPS in relation to the national societies and the European Commission. One point of particular activity is the development of east–west research collaborations, through arranging exchange visits, and providing equipment and funds. Other topics covered are the EPS conferences and publication programs.
High surface area silica xerogels produced using triethoxysilane under non‐supercritical conditions. Molecular hydrogen proposed as the high surface area promoter
Authors: Tour James M. , Kafka Cynthia M.
Published: December 2004

High surface area inorganic oxides find applications as absorbants, fillers, supports, reinforcing agents, and thermal, electrical, and photonic insulators. Supercritical drying, the removal of liquid from the gel pores by heating beyond the critical temperature and pressure of the liquid, is usually a required process step in the production of xerogels based on these materials. Here, an alternative method, not requiring supercritical drying, is presented.
Self‐assembly of semiconductor nanocrystals
Authors: Ulman Abraham
Published: December 2004

The chemisorption of CdS nanocrystals (see Figure) on metal surfaces using alkylthiol monolayers has recently been demonstrated. The significance of this new aspect of self‐organization phenomena in the study of monodispersed clusters and their possible applications are discussed.

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Organic materials for nonlinear optics
Authors: Kaino Toshikuni , Tomaru Satoru
Published: December 2004

This review discusses nonlinear optical (NLO) polymeric materials. As an example of a second‐order NLO material, a novel copolymer with a diazo dye attached is investigated. The second‐order NLO coefficient χ(2)of the copolymer reaches 1.0 × 10−6esu, which is 7 times larger than that of LiNbO3. A third‐order NLO coefficient χ(3)larger than 10−10esu is obtained for polymers where NLO dyes are introduced into the polymer backbone. The optical transmission loss of these polymers is revealed to be around 2 dB/cm. As these polymers can be formed into channel waveguides using the photo‐bleaching technique, they show promise for use in NLO devices because of their processability, transparency and large optical nonlinearity.
Fibers for Optical Communications
Authors: Takahashi Shiro
Published: December 2004

Low‐loss optical fibers based on silica now have a transmission loss value approaching the theoretical limit, and thus attention has turned to other materials. Fibers for optical communications are reviewed in general, and the methods of loss reduction in silica‐based fibers are discussed. Advanced materials and new processing technologies are described for active fibers, in which the light is intentionally modified as it propagates along the fiber, as well as for ultra‐low‐loss passive fibers.
Organic Materials for Third‐Order Nonlinear Optics
Authors: Nalwa Hari Singh
Published: December 2004

The current status of organic low‐molecular weight and polymeric materials for third‐order nonlinear optics is reviewed. The importance of organic materials lies in their promise of large nonlinear optical figure of merit, high optical damage thresholds, ultrafast optical responses, architectural flexibility, and ease of fabrication. Organic materials exhibiting interesting third‐order nonlinear optical properties are discussed to illustrate the importance of structure–property correlations. Results on emerging organic materials that include liquids, dyes, fullerenes, charge‐transfer complexes, π‐conjugated polymers, dye‐grafted polymers, organometallic compounds, composites, and liquid crystals are presented. Organic nonlinear optical materials seem promising for a wide range of applications and their potential for integrated optics should be further explored.
Writing with light on polyaniline films
Authors: Yoneyama Hiroshi
Published: December 2004

Polyanniline films containing TiO2 particles have been shown to be an effective medium for photo‐induced electrochromism. This effect has been utilized to achieve image storage and writing with laser light in the polyaniline films. The production of the films, their applications, and directions for future work, including the incorporation of semiconductor particles into the conducting polymer, are discussed.
Hybrid Nanocomposite Materials—between inorganic glasses and organic polymers
Authors: Novak Bruce M.
Published: December 2004

The sol–gel process, with its associated mild conditions, offers a new approach to the synthesis of composite materials with domain sizes approaching the molecular level. Transparent organic–inorganic composites can be prepared by dissolving preformed polymers into sot–gel precursor solutions, and then allowing the tetraalkyl orthosilicates to hydrolyze and condense to form glassy SiO2 phases of different morphological structures. Alternatively, both the organic and inorganic phases can be simultaneously formed through the synchronous polymerization of the organic monomer and the sol–gel precursors. Depending upon such factors as the structures of the organic and inorganic components, the phase morphology, the degree of interpenetration, and the presence of covalent bonds between the phases, the properties of these composites can vary greatly and range from elastomeric rubbers to high–modulus materials.
Sol‐gel processing of transition‐metal alkoxides for electronics
Authors: Lee G. Rob , Crayston Joe A.
Published: December 2004

High‐temperature superconductors, ferroelectric materials, electrochromic films, and semiconductors are just some of the materials which can be produced from transition‐metal alkoxides using the sol–gel method. The method itself is outlined, the control of the various parameters, such as choice of precursor and medium, and stabilizing ligands, is discussed, and applications over a broad area of materials science are presented.
Dendrimeric silanes
Authors: van der Made Alexander W. , van Leeuwen Piet W. N. M. , de Wilde Janine C. , Brandes Raymond A. C.
Published: December 2004

Silane dendrimers have potential for applications such as stable micelles, building blocks for nanotechnology, X‐ray beam scattering and cores for star‐branched polymers. The Figure shows a first generation silane dendrimer in which the unsaturated terminal groups (the starting points for the production of the second generation) can be seen. The synthesis and properties of these species are discussed.

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Electrochemical muscles: Micromachining fingers and corkscrews
Authors: Smela Elisabeth , Inganäs Olle , Pei Qibing , Lundström Ingemar
Published: December 2004

Millimeter‐scale polymer “fingers” are reported, in which the volume changes of the conjugated polymer polypyrrole that occur in response to electrochemical reduction or oxidation are used to create electrically controlled mechanical actuators. The short bilayer gold and polypyrrole fingers in the Figure can be made to curl by reducing the polypyrrole. The primitive fabrication technique used to make these fingers points the way to the microminiaturization of these artificial muscles.

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The multiple tunnel junction and its application to single‐electron memories
Authors: Nakazato Kazuo , Ahmed Haroon
Published: December 2004

Single‐electron memories and single‐electron logic circuits are two devices that can be constructed from multiple tunnel junctions (MTJs). The electrical characteristics of this basic building block are described, and the fabrication of very small MTJ devices is outlined. The simple structure of the MTJ and the low power consumption and small size of MTJ devices could open up a new era in electron device technology, with devices being constructed from materials completely different from those used in the present semiconductor industry.
Absolute calibration of microwave loss in ESR spectrometers
Authors: Glarum Sivert H. , Ramirez Arthur P. , Haddon Robert C.
Published: December 2004

Studies of field‐dependent microwave losses are useful for the detection and characterization of superconducting materials. The measurements are made in a conventional ESR spectrometer, but until now the data interpretation has been mainly qualitative. A calibration procedure using just a frequency counter, DC voltmeter, and ball bearing is decribed. This allows a quantitative determination of magnetic losses to ∼ 5% accuracy without the need to determine the cavity Q, power level, or field strength.
The zeolate ligand: From hydrolysis to capped semiconductor nanoclusters
Authors: Ozin Geoffrey A.
Published: December 2004

Visualizing the void spaces in zeolites as multidentate multisite macroligands, termed “zeolate ligands”, can lead to new insights. This concept is introduced, the structure, bonding, and reactivity patterns of the zeolate ligand are described and set in the context of the different approaches used to synthesize “capped” nanometer‐dimension semiconductor materials. Finally, the process of depositing epitaxial layers of a II–VI semiconductor on a planar substrate is compared with the intrazeolite topotactic procedure of assembling a II–VI semiconductor nanocluster lattice on the curved internal surface of a zeolite.
New nanocomposites based on “tailor dressed” magnetic particles in a polypyrrole matrix
Authors: Bidan Gérard , Jarjayes Olivier , Fruchart Jean Marc , Hannecart Etienne
Published: December 2004

Nanometer‐sized magnetic particles can be included into polypyrrole to produce composites by means of a novel method involving ferrofluids, in which a magnetic core such as γ‐Fe2O3 is surrounded by an anionic complexing shell (see Figure). This organic coating, leading to the formation of a macroanion, allows the ion to act as a classical doping ion during the polymerization.

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Two‐layer light‐emitting diodes based on sexithiophene and derivatives
Authors: Horowitz Gilles , Delannoy Philippe , Bouchriha Habib , Deloffre Françoise , Fave Jean‐Louis , Garnier Francis , Hajlaoui Riadh , Heyman Michel , Kouki Fayçal , Valat Pierre , Wintgens VÉRonique , Yassar Abderrahim
Published: December 2004

The performance of oligothiophene‐based organic LEDs can be dramatically improved (by up to four orders of magnitude) by using a two‐layer device made of unsubstituted sexithiophene (6T) and a substituted 6T (see Fig.), although the substituted 6T materials do not produce electroluminescence in single‐layer devices. Yellow emission with a quantum yield of 0.15% has been achieved.

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The First sulfur‐containing twin‐DCNQI‐type acceptor
Authors: González Mar , De Miguel Pilar , Martin Nazario , Segura Jose Luis , Seoane Carlos , Orti Enrique , Viruela Rafael , Viruela Pedro M.
Published: December 2004

The search for new electron acceptors and electron donors can facilitated by the use of semiempirical calculations. Here, in a combined experimental and theoretical study the first twin‐DCNQI‐type acceptor is synthesized (see Fig.) and characterized and calculations are used to assess the structural features which should lead to the desired properties.

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Reversible charge transfer complexes between molecular oxygen and poly(3‐alkylthiophene)s
Authors: Abdou Mohamed S. A. , Orfino Frank P. , Xie Zi W. , Deen M. Jamal , Holdcroft Steven
Published: December 2004

The interaction of poly(3‐hexylthiophene), P3HT, with oxygen has been investigated. Evidencein the form of UV–vis absorption, electron paramagnetic resonance data, and a field effect conductivity analysis of a polymer‐based field effect transistor–is presented for the existence of a reversible charge transfer complex between P3HT and oxygen. Oxygen‐sensor applications can be foreseen for thin film transistors incorporating P3HT.
A novel method for the preparation of magnetic nanoparticles in a polypyrrole powder
Authors: Nguyen My T. , Diaz Arthur F.
Published: December 2004

A magnetic polymer composite containing γ‐Fe2O3 nanoparticles and prepared from poly(pyrrole‐N‐propylsulfonate) by a simple reaction with aqueous NH4OH is described. The results of physical characterization by X‐ray powder diffraction and an investigation of the magnetic properties are presented. Such composites incorporating particles of metal oxides are of interest for electromagnetic interference shielding and microwave absorbing applications.
Cost 501, third round
Authors: Schubert Florian
Published: December 2004

The European Concerted Action Research Programs began in 1971. COST 501, which concentrates on materials problems in gas turbines, coal combustion and gasification, and diesel engines, is now entering its third round. The work package concept of the technical program is introduced and highlights of the second round are described. COST 501 provides a good illustration of what can be achieved in long‐term collaborative research with realistic technical targets that are periodically defined by the industries involved.
Characterizing Materials with Cyclic Voltammetry
Authors: Rusling James F. , Suib Steven L.
Published: December 2004

Cyclic voltammetry (CV) is a dynamic electrochemical method for measuring redox events. This summary of recent developments in the use of CV in materials science will be particularly useful for newcomers to the field. Following an introduction to the principles of CV, the current status of investigations of various types of materials are considered : microporous materials, semiconductors. polymer electrode coatings–with a view towards applications in sensors and catalysis–and surfactant films.
On the electronic and vibronic structure of PIC‐aggregates
Authors: Scherer Philipp O. J.
Published: December 2004

Intermolecular excitonic interactions in one‐dimensional molecular aggregates are strong enough to delocalize the electronic excitation coherently over a large number of milecules. Model calculations usually make a number of assumptions, for example that only te nearest neighbor molecules are involved or that te dipole–dipole coupling has a dependence of 1/R3. Here, the electronic structure of the PIC excitations is investigated on the basis of quatum chemical calculations, allowing the validity of the assumptions to be assessed.
Ferromagnetic order in the sulfur‐containing nitronyl nitroxide radical, 2‐(4‐thiomethyl)phenyl‐4,4,5,5‐tetramethylimidazoline‐l‐oxyl‐3‐oxide, NIT(SMe)Ph
Authors: Caneschi Andrea , Ferraro Fabrizio , Gatteschi Dante , le Lirzin Antoine , Novak Miguel A. , Rentschler Eva , Sessoli Roberta
Published: December 2004

Low‐temperature magnetic measurements on powdered samples of the title nitronyl nitroxide radical (see figure) are reported. Evidence for ferromagnetic order with a Tc of ca. 0.2 K is found. It is proposed that the diffuse electronic cloud of the sulfur atom in the radical substituent generates sufficiently strong ferromagnetic interactions even at large distances.

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Dielectric relaxation processes in an antiferroelectric liquid crystal
Authors: de la Fuente M. Rosario , Merino Santos , González Yolanda , Jubindo Miguel A. Pérez , Ros Blanca , Puértolas José A. , Castro Miguel
Published: December 2004

The dielectric properties in a liquid crystal exhibiting ferro, ferri, and antiferroelectric mesophases have been studied. The dielectric response, although complex, allows the characterization of teh various phase transitions in the material. The modes corresponding to the antiferroelectric mesophases are found to be particularly complex and cannot be interpreted on the basis of previously published theories.
Lateral deposition of polypyrrole lines over insulating gaps. Towards the development of polymer‐based electronic devices
Authors: Kranz Christine , Ludwig Markus , Gaub Herrmann E. , Schuhnrann Wolf Gang
Published: December 2004

Molecular wires connecting gold electrodes separated by a 100 μm insulating gap (see Figure) have been produced using a novel method for the microstructured deposition of polypyrrole lines on conducting substrates. The scanning electrochemical microscope used to deposit the lines is described and a microelectrochemical transitor produced using the technique presented.

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Graphene in 3‐dimensions: Towards graphite origami
Authors: Ebbesen Thomas W. , Hiura Hidefumi
Published: December 2004

The systematic construction of graphite structures (for example see Figure and Cover picture) is within reach. These structures are formed accidentally on the surface of HOPG graphite due to the friction exerted by the tip of an atomic force microscope but could also be designed “to order”. The origin of the structures and various approaches for their design are discussed.

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Non‐classical donor–acceptor chromophores for second order nonlinear optics
Authors: Wong Man Shing , Bosshard Christian , Pan Feng , Günter Peter
Published: December 2004

Optoelectronic components require materials with large second‐order nonlinearities. Recently, various types of non‐classical chromophores have been developed, in the hope that they have improved physical properties for materials formation. The main research directions and latest developments reviewed here include multi‐dipolar chromophoric assemblies, multiple donor and acceptor chromophores, non‐rod‐shaped dipolar chromophores, and non‐conjugated donor‐acceptor chromophores, in which the charge transfer process is through space instead of the π‐conjugated bridge.
Intramolecular electron transfer phenomena in purely organic mixed‐valence high‐spin ions: A triplet anion case
Authors: Sedó Josep , Ruiz Daniel , Vidal‐Gancedo José , Rovira Concepció , Bonvoisin Jacques , Launay Jean‐Pierre , Veciana Jaume
Published: December 2004

A purely organic mixed‐valence high‐spin species in which the existence of an electron transfer process has been clearly established by NIR spectroscopy is reported. Since magnetic coupling and electron transfer are by no means independent of each other the opportunity to study the first organic material to exhibit both phenomena is of particular interest.