bluuebunny/crossref_metadata_2025_split 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

AbstractThe 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

AbstractAmorphous 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

AbstractLimited 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

AbstractImportant 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.
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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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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Ceramics from organometallic polymers
Authors: Peuckert Marcell , Vaahs Tilo , Brück Martin 
Published: December 2004

AbstractMaterials 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.
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.magnified image
Ion Beam Modified Polyimide
Authors: Davenas Joël , Boiteux Gisèle 
Published: December 2004

AbstractAltough 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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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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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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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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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).magnified image
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.magnified image
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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Langmuir–Blodgett membranes for separation and sensing
Authors: Tieke Bernd 
Published: December 2004

AbstractThe 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.magnified image
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. magnified image
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. magnified image
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. magnified image
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. magnified image
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. magnified image
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. magnified image
Organic materials for nonlinear optics
Authors: Kaino Toshikuni , Tomaru Satoru 
Published: December 2004

AbstractThis 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.
Organic Materials for Third‐Order Nonlinear Optics
Authors: Nalwa Hari Singh 
Published: December 2004

AbstractThe 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.
Hybrid Nanocomposite Materials—between inorganic glasses and organic polymers
Authors: Novak Bruce M. 
Published: December 2004

AbstractThe 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.
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. magnified image
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. magnified image
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. magnified image
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. magnified image
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. magnified image