bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of the Substrate Geometry on Plasma Synthesis of DLC Coatings
Authors: Bobzin Kirsten , Bagcivan Nazlim , Goebbels Nico , Yilmaz Koray 
Published: May 2009

AbstractDiamond like carbon (DLC) coatings provide very good wear protection in application with machine elements like bearings, gears, shafts and chains. Ensuring the coating characteristics and reproducibility of DLC coatings on different geometries are major concerns in industrial application scale. Due to the change in the plasma intensity, the same coating process can result in different mechanical properties on different geometrical substrate shapes. In order to determine the influence of substrate geometry on the coating characteristics the plasma parameters, such as electron temperature and electron density should be determined. This study presents the effect of the substrate geometry on the plasma synthesis of hydrogen free (a‐C) and hydrogen containing (a‐C:H) DLC coatings deposited by magnetron sputter ion plating (MSIP) technology in an industrial coating facility. The electron temperature, plasma potential and electron density are determined by a Langmuir probe at two different substrate geometries, such that one of them has a planar and the other one has an angular surface, which corresponds to the geometries of a bearing and a gear, respectively. The adhesion and the mechanical characteristics, i.e. universal hardness and Young's modulus, of the DLC coatings are determined by scratch test and nanoindentation, respectively. The dependency of the mechanical characteristics on the plasma parameters for different geometrical surfaces is examined and the results are compared. The results show that depending on the plasma gas, either pure argon or mixture of argon and acetylene, the substrate geometry has a significant effect on mechanical properties and adhesion.
Deposition of Thin SiOx Films by Direct Precursor Injection in Atmospheric Pressure Microwave Torch (TIA)
Authors: Asad Syed Salman , Lavoute Jean Pierre , Dublanche‐Tixier Christelle , Jaoul Cédric , Chazelas Christophe , Tristant Pascal , Boisse‐Laporte Caroline 
Published: May 2009

AbstractAn axial injection torch (TIA, Torche à Injection Axiale) contained in an open air deposition chamber has been exploited to deposit thin silicon oxide films. The organosilicon precursor, tetramethylsilane (TMS), was injected directly in the plasma gas. A parametric study was carried out to study the effects of microwave power, precursor quantity and torch to substrate distance on the film deposition process. Inorganic films were obtained without the addition of oxygen in the system as the oxygen got incorporated in the plasma from the open air, as shown by optical spectroscopic studies on the plasma. The deposited films were characterised using different techniques like Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), elastic recoil detection analysis (ERDA), Rutherford backscattering spectroscopy (RBS) and nuclear resonance analysis (NRA). These analyses helped understanding the factors affecting the film deposition process. Results show that at short processing time, low microwave plasma power and precursor quantity at an optimised torch to substrate distance, thin non‐porous hydrogenated silicon oxide‐like films can be deposited at low substrate temperatures of around 370 K using this technique.
Measurements of Deposition Rate and Substrate Heating in a HiPIMS Discharge
Authors: West Glen , Kelly Peter , Barker Clara , Mishra Anurag , Bradley James 
Published: May 2009

AbstractThe thermal energy flux delivered to the substrate position was measured for continuous‐dc, pulsed dc‐ and high‐power impulse magnetron sputtering (HiPIMS) magnetron discharges at the same time‐averaged discharge powers. These values were subsequently normalised for measured deposition rates. Titanium coatings were grown under the same process conditions and analysed for alterations in crystal structure via X‐ray diffraction. The HiPIMS discharges were found to deliver a significantly lower normalised thermal energy flux to the substrate than both continuous‐dc and pulsed‐dc sputtering, which is of potential benefit in coating temperature‐sensitive substrates; whilst also enabling frequency‐dependent modification of film properties resulting from the ionised deposition flux inherent in this process.
Thickness Control of Coatings by Means of Modulated IR Radiometry
Authors: Macedo Francisco , Vaz Filipe , Fernandes Ana C. , Fotsing Jean L. Nzodoum , Gibkes Juergen , Pelzl Josef , Bein Bruno K. 
Published: May 2009

AbstractCoatings prepared by reactive magnetron sputtering of approximately equal thermal transport properties but differing coating thicknesses are analyzed by means of non‐contact non‐destructive modulated IR radiometry. For the quantitative interpretation, the measured thermal wave signals are calibrated, using the signals measured for a homogenous opaque solid of smooth surface. The relative minima of the inverse calibrated phase lag signals are interpreted with respect to the effective thermal transport properties and to the coating thickness using an inverse solution of the two‐layer thermal wave problem. Based on measurements of various coatings, the limitations of this thermal wave method and the errors of measurement for the coating thickness are discussed by comparing with microscopic measurements.
Deposition of TiO2‐Based Layer on Textile Substrate: Theoretical and Experimental Study
Authors: Bartoš Petr , Špatenka Petr , Volfová Lenka 
Published: May 2009

AbstractThis paper is aimed on both the experimental and the theoretical study of textile surface modification by the plasma‐enhanced chemical vapour deposition (PECVD). In the first part of this paper we describe experimental measurements of the layer profile that is deposited on the surface of a textile thread. The SEM photos of the TiO2‐based layer on fibres showed that the layer thickness changes significantly with the location of the fibre in the fabric. Although both the layer thickness and its profile are crucial quantities for many technical applications, the detailed description of the layer profile experimentally is almost impossible. Therefore, a computer model was developed that enable us to predict the layer structure on the surface of the thread in fabric. This computer model can be used effectively as a sub‐model in other areas of theoretical research.
Carbon Nanotubes Functionalized in Oxygen and Water Low Pressure Discharges used as Reinforcement of Polyurethane Composites
Authors: Zajíčková Lenka , Kučerová Zuzana , Buršíková Vilma , Eliáš Marek , Houdková Jana , Synek Petr , Maršíková Helena , Jašek Ondřej 
Published: May 2009

AbstractThe functionalization of multi‐walled CNTs in O2/Ar and H2O/Ar low pressure capacitive discharges was studied by XPS and FT‐IR. The pristine and functionalized CNTs were used as fillers in polyurethane paints. Successful plasma functionalization was confirmed by changes in atomic composition and chemical shift of the XPS atomic signals. The functionalization was indicated also by the shift of IR absorption peaks corresponding to the motion of carbon skeleton, especially the peak at about 1 560 cm−1. The presence of carbonyl was confirmed by IR absorption peak at 1 723 cm−1 only for O2/Ar plasma. The plasma functionalized CNTs increased significantly the universal and plastic hardness of the CNTs reinforced polyurethane as compared to the composites with pristine CNTs.
Morphology and Structure of C:Co, C:V, and C:Cu Nanocomposite Films
Authors: Berndt Markus , Krause Matthias , Abrasonis Gintautas , Mücklich Arndt , Munnik Frans , Kolitsch Andreas , Möller Wolfhard 
Published: May 2009

AbstractThe influence of transition metals (TM) type on the encapsulating carbon (C) medium during the growth of C:TM (TM = V, Co and Cu) composite films with a metal content of ∼30 at.‐% grown by ion beam co‐sputtering in the temperature range of RT‐500 °C is investigated by means of X‐ray diffraction, transmission electron microscopy and Raman spectroscopy. The nanostructure of both C:TM nanocomposite constituents is strongly affected by the TM type and the growth temperature. The nanoparticle size, shape, and phase depend on these parameters. Raman spectroscopy shows that all three metals enhance six‐fold ring clustering of the carbon phase independent of the nanoparticle type, size, shape and phase, and the effect is most pronounced at lower temperatures.
Systematic approach to incorporate human factors into a process plant design
Authors: Widiputri Diah Indriani , Löwe Katharina , Löher Heinz‐Josef 
Published: May 2009

AbstractDespite the increasing number of accidents in process industry caused by human error, there are still too few efforts devoted to this area. This is mainly caused by people's tendency to overestimate human's capability in interacting with their working environment and moreover by the unavailability of reliable analysis methods.Because of the current lack of adequate methods, human factors (HF) analysis is not widely performed in process industry. Some HF techniques developed in the process industry were examined regarding their practical applicability and were unfortunately proved to be unsuitable for an elaborate HF analysis. Therefore, a new approach was developed, which provides a systematic way in performing a qualitative HF analysis to achieve a safer operation and decrease the number of human failure events.HF consideration during the design of a process plant is the key to minimize accidents caused by human error in process industry. Thus, an approach to incorporate HF into design phase is described in this article, which can help achieving a safer operation as early as possible with minimized costs. © 2009 American Institute of Chemical Engineers Process Saf Prog 2009
The important role of pressure in supercritical fluid process development revealed by reaction calorimetry
Authors: Mantelis Charalampos A. , Meyer Thierry 
Published: May 2009

AbstractThe technique of reaction calorimetry adapted for use with reactions in supercritical fluids was used to study some safety aspects of the free‐radical dispersion polymerization of methyl methacrylate in scCO2. The reaction heat rate profile was found to change very little once the dispersion was well formed. Furthermore, it provided valuable information for the calculation of the maximum temperature attainable by the synthesis reaction (MTSR) in the case of a hypothetical cooling system failure. Finally, a series of failure scenarios demonstrated the importance of the pressure as far as the safety of the process is concerned, due to the particularity of the supercritical state of the solvent. It was found that the acceleration phase of the reaction is the most critical period, since a cooling system failure during this phase leaves very little time before the pressure overcomes the operational limit of the equipment and results in an accident. Hence, the utility and the importance of defining the reaction heat rate profile become obvious and several safety features have to be taken into consideration when designing a SCF process. © 2009 American Institute of Chemical Engineers Process Saf Prog 2009
Structure dependence of biological activities for primate cathelicidins
Authors: Tomasinsig Linda , Morgera Francesca , Antcheva Nikolinka , Pacor Sabrina , Skerlavaj Barbara , Zanetti Margherita , Tossi Alessandro 
Published: May 2009

AbstractWe have analysed the effects of variations in orang‐utan (ppy), rhesus macaque (mmu) and leaf eater (pob) monkey orthologues of the human cathelicidin LL‐37, on a range of relevant biological activities. These host defence peptides range in cationicity from +4 to +10, and while the more cationic pob and mmuRL‐37 are in a monomeric and unstructured form in bulk solution (F‐form), the human and ppyLL‐37 are in an aggregated/helical form (A‐form). The in vitro antibacterial activity depended strongly on both the structural form and the charge. F‐form peptides were more potent against Gram‐positive and ‐negative bacteria and less salt, medium or serum sensitive than A‐form ones. CD studies suggested that A‐ and F‐form peptides interact with LPS in different manners, but the ability to detoxify it did not correlate directly with either the charge or structure. Toxicity towards eukaryotic cells also showed a varied dependence on the peptides' physical characteristics. Haemolytic activity was similar for all the tested peptides while other cytotoxicity assays revealed the highly cationic, F‐form pobRL‐37 as the most toxic, followed by the A‐form human LL‐37. As shown with the human peptide, toxicity depended markedly on the nature and metabolic state of the target cell. Our results suggest that different evolutionary trajectories for each orthologue lead to distinct sets of physical characteristics, which significantly differentiates their biological activities. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Antimicrobial and cytotoxic activities of Malaysian endophytes
Authors: Ramasamy Kalavathy , Lim Siong Meng , Bakar Hamidah Abu , Ismail Noorliana , Ismail Maria Suhana , Ali Muhamad Fuad , Faizal Weber Jean‐Frédéric , Cole Anthony L. J. 
Published: May 2009

AbstractEndophytes, which are receiving increasing attention, have been found to be potential sources of bioactive metabolites following the discovery of paclitaxel producing endophytic fungi. In the present study, a total of 348 endophytes were isolated from different parts of 24 Malaysian medicinal plants. Three selected endophytes (HAB10R12, HAB11R3 and HAB21F25) were investigated for their antimicrobial and cytotoxic activities. For antimicrobial activity, HAB10R12 and HAB11R3 were found to be most active against bacteria and fungi, respectively. Their antimicrobial effects were comparable to, if not better than, a number of current commercial antibacterial and antifungal agents. Both HAB10R12 and HAB21F25 were found to be potential anticancer drug candidates, having potent activity against MCF‐7 and HCT116 cell lines and warrant further investigation. Copyright © 2009 John Wiley & Sons, Ltd.
Spin crossover in Fe(II) complexes: An ab initio study of ligand σ‐donation
Authors: Domingo Alex , Àngels Carvajal Maria , de Graaf Coen 
Published: May 2009

AbstractThe relative stability of high‐spin and low‐spin states has been studied in a series of Fe(II) complexes with model ligands of different σ donation strength. The natural (delocalized) orbitals are transformed to atomic‐like orbitals to analyze the multiconfigurational wave function in a valence bond picture. This analysis reveals a direct relation between the stabilization of the low‐spin state and the importance of the ligand‐to‐metal charge transfer in the σ orbitals. The multiconfigurational second‐order perturbation theory (CASPT2) energy dependence of the low‐spin state as function of the Fe‐ligand distance deviates significantly from coupled cluster (CCSD(T)) calculations. This is ascribed to the intrinsic multiconfigurational character of the wave function of the low‐spin state, invalidating the use of the simple closed‐shell reference in the coupled cluster calculations. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Cusps and derivatives for wave‐functions expanded in Slater orbitals: A density study
Authors: Reinhardt Peter , Hoggan Philip E. 
Published: May 2009

AbstractThis article recalls basic properties of Slater type Orbital (STO) basis sets, in particular, with respect to satisfying Kato's electron‐nucleus cusp condition. It is shown that a suitable starting point is the set of hydrogen‐like orbitals or, more flexibly, their generalization as Coulomb Sturmians. A case study is presented on the Hartree–Fock density obtained for a water molecule, N2, and CO2 showing that the nuclear cusp condition may be easily accounted for near the heavier nuclei, but only with difficulties at the hydrogen center. In particular, bond stretching affects the expected cusp condition on hydrogen atoms. Some indications are given on the improvement of STO basis sets. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Microscopic branching processes: The O + O2 reaction and its relaxed potential representations
Authors: Rampino Sergio , Skouteris Dimitris , Laganà Antonio 
Published: May 2009

AbstractAn analysis of the O3 DMBE potential energy surface is performed using unconventional contour maps. In this way alternative paths leading to the same products (microscopic branching) are singled out. The detailed J = 0 quantum probabilities and related mode selectivity and energy disposal obtained through an extensive computational campaign on the EGEE production Grid are interpreted in terms of the mentioned alternative reactive paths. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Molecular recognition in cation‐exchanged zeolites
Authors: Pidko Evgeny A. , van Santen Rutger A. 
Published: May 2009

AbstractThe concepts of confinement‐ and molecular recognition‐driven chemical reactivity of cation‐exchanged zeolites is illustrated by our recent results from periodic and cluster density functional theory (DFT) calculations. The reactivity of alkali‐earth‐ and alkaline‐exchanged low‐silica zeolites for selective photo‐oxidation of alkenes with molecular oxygen and for N2O4disproportionation is shown to be mainly due to the specific arrangement and the size of the cations in the zeolite cage. An attempt is made to separate the effects of basicity of the framework, the Lewis acidity of the extra‐framework cations and the electrostatic field in the zeolite cage as well as its geometrical properties for the respective reactions. The importance of the favorable adsorption fashion of the reagents controlled by noncovalent interactions with the microporous matrix is shown. The role of the weak interactions with the zeolite walls and the factors, which determine the preference for a particular adsorption mode, are discussed by the example of light alkanes adsorption to Mg‐ and Ca‐exchanged faujasites. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Phase behavior of ionic clusters down to nanoscale. A review of recent work
Authors: Rodrigues Pedro C. R. , Silva Fernandes Fernando M. S. 
Published: May 2009

AbstractAs finding an exact and manageable partition function for nanoclusters is a desirable but, so far, unattainable task, approximated treatments are proposed to explain and predict phase changes and phase coexistence at these size scales. In this article, a review of those approaches is presented, mainly focusing the authors work on the subject. The foundations and limitations of the proposed models are discussed and perspectives for extended treatments are given. The discussions are illustrated with new molecular dynamics simulations of unconstrained NaI and NaCl clusters. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Davydov's solitons in a homogeneous nucleotide chain
Authors: Lakhno Victor D. 
Published: May 2009

AbstractCharge transfer in homogeneous nucleotide chains is modeled on the basis of Holstein Hamiltonian. The path length of Davydov solitons in these chains is being studied. It is shown that in a dispersionless case, when the soliton velocity V is small, the path length grows exponentially as V decreases. In this case, the state of a moving soliton is quasisteady. In the presence of dispersion determined by the dependence Ω2 = Ω + Vκ2, the path length in the region 0 < V < V0 is equal to infinity. In this case, the phonon environment follows the charge motion. In the region V > V0, the soliton motion is accompanied by emission of phonons which leads to a finite path length of a soliton. The latter tends to infinity as V → V0 + 0 and V → ∞. The presence of dissipation leads to a finite soliton path length. An equilibrium velocity of soliton in an external electric field is calculated. It is shown that there is a maximum intensity of an electric field at which a steady motion of a soliton is possible. The soliton mobility is calculated for the stable or ohmic brunch. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
The effect of drug‐DNA interactions on the intercalation site formation
Authors: Miroshnychenko K. V. , Shestopalova A. V. 
Published: May 2009

AbstractThe problem of intercalation site formation in the undistorted B‐DNA of different length and sequence was considered. Three models of DNA intercalation targets were proposed that accounted for the binding features of intercalators ethidium, daunomycin and 9‐amino[N‐(2‐dimethylamino)ethyl]‐acridine‐4‐carboxamide (9‐amino‐DACA). The automated docking of ligands into the constructed DNA‐targets produced correct structures of complexes for ethidium and daunomycin when asymmetrically unwound DNA was used as target. To obtain the correct structure of 9‐amino‐DACA‐DNA complex, the manual docking was applied. The results of docking of ligands into different DNA‐targets indicate that, upon formation of the intercalation target, it is sufficient to take into account only the most significant unwinding in one particular helical step: in the intercalation step (for ethidium and 9‐amino‐DACA) or in the adjacent helical step (for daunomycin). The unwinding or overwinding of subsequent helical steps could be refined later during the optimization of the obtained intercalation complex. The unwinding of the DNA helical step on the large angle produces the 5′‐North/3′‐South asymmetry of sugar conformations in this step. The value of the total unwinding of the DNA in the intercalation complex was found to be dependent on the sequence and length of the DNA‐target. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Biocompatible Near‐Infrared Quantum Dots as Ultrasensitive Probes for Long‐Term in vivo Imaging Applications
Authors: Yong Ken‐Tye , Roy Indrajit , Ding Hong , Bergey Earl J. , Prasad Paras N. 
Published: May 2009

AbstractA facile synthesis method to produce monodisperse, biocompatible, lysine crosslinked mercaptoundecanoic acid (MUA) CdSe0.25Te0.75/CdS near‐infrared (NIR) quantum dots and use them as probes to study their long term in vivo distribution, clearance, and toxicity is presented. Large signal enhancements are demonstrated by these quantum dots, which enables their use as efficient and sensitive probes for live‐animal imaging. An important finding is that mice intravenously injected with ≈10.5 mg kg−1 of NIR QDs survive for more than three months without any apparent adverse effect to their health. Furthermore, it is determined that there is a significant reduction in the number of the QDs in the liver and spleen three months post injection. In addition, histological analysis of heart, kidney, liver, spleen, and lung tissue indicates that there are no acute toxic effects from these lysine cross‐linked MUA NIR QDs. This study suggests that these NIR QDs can be potentially used for long‐term targeted imaging and therapy studies in vivo.