bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cathode Current Density Distributions in High Power Impulse and Direct Current Magnetron Sputtering Modes
Authors: Clarke Gregory , Mishra Anurag , Kelly Peter J. , Bradley James W. 
Published: May 2009

AbstractDuring the operation of high power impulse magnetron sputtering discharges, peak currents in excess of 1 000 A may be observed, leading to large instantaneous power levels. To investigate this method of operation, a series of planar probes have been constructed that allow for the spatial and temporal variations of current across the surface of a cathode to be assessed. These measurements provide information on the flux of charged particles to and from the cathode whilst it is being sputtered. Under operating conditions that led to a peak current of 140 A, measured current densities varied spatially from ∼0.1 to 1.5 A · cm−2. By the use of a simple model, the measured current densities were used to predict the sputtering rate of the cathode, which allowed for the erosion profile and target lifetime to be estimated. The results suggest that, with regard to sputtering, operating in HiPIMS mode may be less energy efficient than operating in DC mode, but may achieve a higher target utilisation fraction.
Thermal Characterization and Optimization of a Plasma Downstream Reactor for Particle Surface Modification
Authors: Roth Christian , Spillmann Adrian , Sonnenfeld Axel , Rudolf von Rohr Philipp 
Published: May 2009

AbstractA plasma downstream reactor for the continuous treatment of dry, cohesive, and temperature sensitive powders is investigated by means of fiber optic temperature measurements. A method to determine the different heat flux terms (plasma heating, radiation, and convection) is introduced and applied to calculate the inner wall and neutral gas temperature at several positions within the reactor. By this means undesirable discharge regions downstream the plasma zone are found. Consequently, the thermal characterization of the reactor allows optimization of the reactor design to confine the plasma to the downer tube and to avoid undesirable temperature hot spots.
Optical Emission Spectroscopy Analysis of Ar/N2 Plasma in Reactive Magnetron Sputtering
Authors: Bousquet Angélique , Spinelle Laurent , Cellier Joël , Tomasella Eric 
Published: May 2009

AbstractThe ternary silicon carbide‐nitride SiCxNy presents very promising properties: hardness, low chemical reactivity, and resistance to oxidation. This material can be deposited by various processes, but reactive magnetron sputtering is one of the most versatile. In this paper, we investigated by optical emission spectroscopy an argon‐nitrogen plasma used with a silicon carbide target to deposit SiCxNy films. First, we observed the physical aspect of the discharge is modified not only with the injected atmosphere but also with target surface state, which highly influences the N2 dissociation rate. Then, we followed two species coming from target sputtering: CN and Si. This study confirms the target nitriding up to a certain N2 fraction. Finally, the OES information was related to the deposited film composition.
Silicon Oxide Barrier Coatings Deposited on Polymer Materials for Applications in Food Packaging Industry
Authors: Schneider Joachim , Akbar Muhammad Iqbal , Dutroncy Jerôme , Kiesler Dennis , Leins Martina , Schulz Andreas , Walker Matthias , Schumacher Uwe , Stroth Ulrich 
Published: May 2009

AbstractDeposition of SiOx layers by low‐pressure microwave plasmas is an excellent means to add missing barrier functionalities to cheap and material‐saving homo‐polymeric materials that will increasingly replace expensive multi‐layer polymer food packaging. SiOx coatings were deposited in an ECR plasma process on polyethyleneterephthalate (PET) foils using two different precursors, HMDSO and HMDSN. O2 transition rates of less than 1 cm3 (m−2·24 h−1·bar−1) were obtained for the best performing SiOx coatings deposited from O2/HMDSN gas mixtures. First ECR plasma deposition tests on polypropylene (PP) trays show the high barrier potential of SiOx coatings even on three‐dimensional polymer food packaging.
Investigation of Plasma Parameters in a VHF Plasma With Narrow Gap Under High Gaseous Pressure
Authors: Muta Hiroshi , Kishida Shinichi , Tanaka Masayoshi , Yamauchi Yasuhiro , Baba Tomoyoshi , Takeuchi Yoshiaki , Takatsuka Hiromu , Kawai Yoshinobu 
Published: May 2009

AbstractThe plasma parameters in a VHF plasma with a narrow gap under high gaseous pressure were experimentally investigated. As a result of the Langmuir probe measurement for hydrogen plasma with a gap length of 5 mm and a pressure of 1 torr, it was found that the electron temperature (∼10 eV) was high enough to promote the dissociation reaction of SiH4 molecules, and that a large amount of negative ions which could play a role in reducing the sheath potential were produced. On the other hand, the results of the ion measurement using a quadrupole mass spectrometer with an energy analyzer indicated that the highest produced ion was H and its incident energy to the substrate was low due to the collisions. These results suggest that the condition of high pressure and narrow gap are advantageous for the preparation of high‐quality µc‐Si thin films.
In Situ Diagnostics of RF Magnetron Sputtering of Nylon
Authors: Kousal Jaroslav , Hanuš Jan , Choukourov Andrei , Polonskyi Oleksandr , Biederman Hynek , Slavínská Danka 
Published: May 2009

AbstractPlanar RF magnetron was used for sputtering of nylon in Ar, N2 and their mixtures. The discharge plasma was monitored by mass spectrometry and optical emission spectroscopy. By means of these two diagnostic methods various carbon‐containing species were detected and their densities were found to increase with increasing portion of N2 in the discharge mixture. Moreover, it has been demonstrated that such species govern the deposition rate as well as chemical composition of the deposits determined both in situ and ex situ by FT‐IR spectroscopy and XPS.
Effect of Plasma Treatment on Polymer Track Membranes
Authors: Kravets Lyubov , Dmitriev Serguei , Dinescu Gheorghe , Lazea Andrada , Satulu Veronica 
Published: May 2009

AbstractThe effect of plasma treatment on the properties of poly(ethylene terephthalate) track membranes has been investigated. The influence of plasma treatment conditions and composition of plasma‐forming gas on basic membrane characteristics–pore size and shape, wettability, hydrodynamic, and electrochemical properties–were studied. It is shown that the plasma treatment of membranes can significantly improve their performance characteristics and give them a lot of useful properties.
DC Magnetron Sputtering Deposition of Titanium Oxide Nanoparticles: Influence of Temperature, Pressure and Deposition Time on the Deposited Layer Morphology, the Wetting and Optical Surface Properties
Authors: Dreesen Laurent , Cecchet Francesca , Lucas Stéphane 
Published: May 2009

AbstractTitanium dioxide nanoparticles were prepared on glass substrates by reactive DC magnetron sputtering. As highlighted by the atomic force microscopy characterization, we were able to control the nanoparticles' surface coverage and diameter by varying the deposition time and the total pressure, respectively. The titanium dioxide energy band gap, determined by using ultraviolet‐visible spectroscopy, depends on the total pressure but is quite independent on the deposition temperature. On the contrary, it is blue shifted when the pressure increases. Finally, the contact angles slightly decrease after ultraviolet illumination irrespective of the different deposition parameters, indicating an improvement of the hydrophilic properties of the adsorbed layer. After 21 h in dark, the contact angles are nearly identical to the ones before exposure to UV light: the samples do not keep their hydrophilic behaviour.
Plasma Enhanced Chemical Vapor Deposition on Particulate Solid‐State Materials for Improved Powder Processing
Authors: Sonnenfeld Axel , Roth Christian , Dimitrova Zorica , Spillmann Adrian , von Rohr Philipp Rudolf 
Published: May 2009

AbstractThe surface of fine lactose powder particulates was modified by direct‐plasma exposure in a radio frequency (RF) discharge, in a mixture of oxygen and hexamethyldisiloxane (HMDSO) diluted in argon. Besides, the RF power (100–500 W) and the HMDSO flow rate (0–68 sccm) at constant oxygen‐to‐HMDSO flow rate ratio of 10 was varied in this study. Apart from the relatively high pressure of 2 mbar, the plasma process adopted is very much alike the plasma enhanced chemical vapor deposition of silica‐like material descending from the plasma‐chemical reaction of oxygen and HMDSO. With respect to the processability of powders in production lines to be solely gravity‐driven, as for instance in the event of dye‐filling, compression ratios (based on the powder bulk and mass density) were measured for solely gravity‐driven filling of a graduated glass. A jolting volumeter was used to provide the compressibility of the compacted powder bulk. Higher compressibility of about 20% (improvement rate) was found for both experimental series: variation of HMDSO flow rate and variation of the discharge power. In both cases, an enhancement of the flowability of the powder was found to cause the compressibility improvement.
A Versatile System for Large Area Coating of Nanocomposite Thin Films
Authors: Schmittgens Ralph , Wolf Marcus , Schultheiss Eberhard 
Published: May 2009

AbstractA deposition system process in a vacuum environment has been designed to produce plasma generated nanoparticles of metals, alloys, or inorganic compounds. The system allows coating various substrates with nanoparticle films and with nanocomposite films made of nanoparticles in plasma generated matrix material. The system is composed of a modified gas flow sputter (GFS) source of a hollow cathode type that allows generating metal and inorganic composite particles through a gas phase condensation (GPC) process. A plasma‐enhanced chemical vapor deposition (PECVD) source is used to deposit matrix materials based on organic precursors. The PECVD is a 60 MHz driven pulsed discharge and allows obtaining high deposition rates and a wide variety of the matrix film characters in the range from inorganic compounds to plasma polymers through changes in source parameters and precursors. The design details of the vacuum system and of the plasma sources are reported and the deposition procedure is presented. First results on the generation of metal nanoparticles as a function of the principal discharge parameters of the GFS source are given.
Properties of WC‐CoCr Based Coatings Deposited by Different HVOF Thermal Spray Processes
Authors: Picas Josep A. , Punset Miquel , Baile M. Teresa , Martín Enric , Forn Antonio 
Published: May 2009

AbstractThe technology of high‐velocity oxygen fuel (HVOF) thermal spraying is today one of the more important processes used to apply carbide based coatings. HVOF spraying has been transforming from gas‐fuelled towards liquid‐fuelled systems. An apparent benefit from this development is to use low‐cost fuels such as kerosene. In this work a WC‐CoCr powder was thermally sprayed by three different variants of the high velocity oxy‐fuel process, in which the fuels were hydrogen and kerosene. This study was carried out in order to evaluate the influence of HVOF spray parameters on some coating properties. Investigations into the microstructural evolution of the coatings, using scanning electron microscopy and X‐ray diffraction, are presented along with results on their mechanical and tribological properties.
Mechanical Properties of Layers Obtained by DC‐Pulsed Plasma Nitriding on a Low‐Alloy Steel (AISI 4140)
Authors: Dutrey Luciano , De Las Heras Evangelina , Svoboda Hernán G. , Corengia Pablo A. 
Published: May 2009

AbstractAn industrial DC‐pulsed plasma nitriding (DCPPN) equipment was used to obtain samples of an AISI 4140 low‐alloy steel with five different configurations: substrate, substrate + diffusion zone, diffusion zone, substrate + diffusion zone + compound layer, and diffusion zone + compound layer. The microstructures of the samples were investigated by scanning electron microscopy and X‐ray diffraction. Microhardness and tensile tests were performed, and the fracture mechanisms for the different materials were finally analyzed and discussed. The DCPPN produced an increase in the elastic modulus as well as in the yield strengths, together with a pronounce ductility loss, associated to the brittle intergranular fracture surface due to the nitride precipitation in the grain boundaries.
Treatment of Hexatriacontane by Ar–O2 Remote Plasma: Formation of the Active Species
Authors: Mafra Marcio , Belmonte Thierry , Poncin‐Epaillard Fabienne , Maliska Ana , Cvelbar Urŏs 
Published: May 2009

AbstractTo follow the interaction with a heavy alkane, the hexatriacontane, and a remote argon–oxygen plasma, the O2 (b1Σ, v = 0 − X3Σ, v′ = 0) transition at 762 nm can be used. A strong correlation with the material transformation is observed and attributed to atomic oxygen whose recombination releases a quantity of heat that affects the treatment temperature.
Paramagnetic relaxation enhancements in unfolded proteins: Theory and application to drkN SH3 domain
Authors: Xue Yi , Podkorytov Ivan S. , Rao D. Krishna , Benjamin Nathan , Sun Honglei , Skrynnikov Nikolai R. 
Published: May 2009

AbstractSite‐directed spin labeling in combination with paramagnetic relaxation enhancement (PRE) measurements is one of the most promising techniques for studying unfolded proteins. Since the pioneering work of Gillespie and Shortle (J Mol Biol 1997;268:158), PRE data from unfolded proteins have been interpreted using the theory that was originally developed for rotational spin relaxation. At the same time, it can be readily recognized that the relative motion of the paramagnetic tag attached to the peptide chain and the reporter spin such as 1HN is best described as a translation. With this notion in mind, we developed a number of models for the PRE effect in unfolded proteins: (i) mutual diffusion of the two tethered spheres, (ii) mutual diffusion of the two tethered spheres subject to a harmonic potential, (iii) mutual diffusion of the two tethered spheres subject to a simulated mean‐force potential (Smoluchowski equation); (iv) explicit‐atom molecular dynamics simulation. The new models were used to predict the dependences of the PRE rates on the 1HN residue number and static magnetic field strength; the results are appreciably different from the Gillespie–Shortle model. At the same time, the Gillespie–Shortle approach is expected to be generally adequate if the goal is to reconstruct the distance distributions between 1HN spins and the paramagnetic center (provided that the characteristic correlation time is known with a reasonable accuracy). The theory has been tested by measuring the PRE rates in three spin‐labeled mutants of the drkN SH3 domain in 2M guanidinium chloride. Two modifications introduced into the measurement scheme—using a reference compound to calibrate the signals from the two samples (oxidized and reduced) and using peak volumes instead of intensities to determine the PRE rates—lead to a substantial improvement in the quality of data. The PRE data from the denatured drkN SH3 are mostly consistent with the model of moderately expanded random‐coil protein, although part of the data point toward a more compact structure (local hydrophobic cluster). At the same time, the radius of gyration reported by Choy et al. (J Mol Biol 2002;316:101) suggests that the protein is highly expanded. This seemingly contradictory evidence can be reconciled if one assumes that denatured drkN SH3 forms a conformational ensemble that is dominated by extended conformations, yet also contains compact (collapsed) species. Such behavior is apparently more complex than predicted by the model of a random‐coil protein in good solvent/poor solvent.
Fusion order controls expression level and activity of elastin‐like polypeptide fusion proteins
Authors: Christensen Trine , Amiram Miriam , Dagher Sue , Trabbic‐Carlson Kimberly , Shamji Mohammed F. , Setton Lori A. , Chilkoti Ashutosh 
Published: May 2009

AbstractWe have previously developed a method to purify recombinant proteins, termed inverse transition cycling (ITC) that eliminates the need for column chromatography. ITC exploits the inverse solubility phase transition of an elastin‐like polypeptide (ELP) that is fused to a protein of interest. In ITC, a recombinant ELP fusion protein is cycled through its phase transition, resulting in separation of the ELP fusion protein from other Escherichia coli contaminants. Herein, we examine the role of the position of the ELP in the fusion protein on the expression levels and yields of purified protein for four recombinant ELP fusion proteins. Placing the ELP at the C‐terminus of the target protein (protein‐ELP) results in a higher expression level for the four ELP fusion proteins, which also translates to a greater yield of purified protein. The position of the fusion protein also has a significant impact on its specific activity, as ELP‐protein constructs have a lower specific activity than protein‐ELP constructs for three out of the four proteins. Our results show no difference in mRNA levels between protein‐ELP and ELP‐protein fusion constructs. Instead, we suggest two possible explanations for these results: first, the translational efficiency of mRNA may differ between the fusion protein in the two orientations and second, the lower level of protein expression and lower specific activity is consistent with a scenario that placement of the ELP at the N‐terminus of the fusion protein increases the fraction of misfolded, and less active conformers, which are also preferentially degraded compared to fusion proteins in which the ELP is present at the C‐terminal end of the protein.
Quasi‐static contact problem with finitely many degrees of freedom and dry friction
Authors: Schmid F. 
Published: May 2009

AbstractA quasi‐static contact problem is considered for a nonlinear elastic system with finitely many degrees of freedom. The friction law of Coulomb is used to model friction and the friction coefficient may be anisotropic and may vary along the surface of the rigid obstacle. Existence is established following a time‐incremental minimization problem. Friction is artificially decreased to resolve the discontinuity arising from making and losing contact.
Processing Loaner Instruments in an Ambulatory Surgery Center
Authors: Huter‐Kunish Gloria G. 
Published: May 2009

AbstractLoaner instruments often do not arrive at receiving facilities in the time frame or the condition that is needed to use them safely. Their cleaning and decontamination status may be unknown. There may be no inventory of what has been loaned or information about processing requirements for the instrument's use. These situations can create problems for both the loaning facility and the receiving facility and must be addressed to reduce costs from damage to or loss of instruments.The use of documents and checklists to verify the cleaning, decontamination, and sterilization processes used allows ambulatory surgery centers to solve these problems, cut costs, and protect staff members and patients. AORN J 89 (May 2009) 861–866. © AORN, Inc, 2009.
Acute abdominal pain in women at an emergency department: Predictors of chronicity
Authors: Weijenborg Philomeen Th M , Gardien Kim , Toorenvliet Boudewijn R , Merkus Jos WS , ter Kuile Moniek M 
Published: May 2009

AbstractBackground: Persistence of pain after acute abdominal pain has been encountered but predictors of chronicity are insufficiently known.Aims: To assess the course of acute abdominal pain and to explore whether chronicity is predicted by baseline demographic and clinical variables.Methods: A follow‐up study was conducted on all consecutive women who had visited an emergency department of a secondary care teaching hospital for acute abdominal pain. After a mean of 2.3 years 115 women (58%) completed questionnaires.Results: At follow‐up 34 women (30%) still suffered from abdominal pain complaints for more than 3 months the past year. Low education level (Exp(B) = 4.21, p = 0.017) and having experienced abuse before the age of 16 (Exp(B) = 3.14, p = 0.016) were significantly and independently associated with chronicity. No other socio‐demographic or clinical factors predicted the outcome.Conclusion: At a 2.3 year follow‐up period nearly one third of all women with acute abdominal pain still suffered from pain. Low education level and abuse at younger age showed to be risk factors for pain persistence.
Estrogen receptor overexpression in malignant minor salivary gland tumors of the sinonasal tract
Authors: Luo Sheng‐Dean , Su Chih‐Ying , Chuang Hui‐Ching , Huang Chao‐Cheng , Chen Ching‐Mei , Chien Chih‐Yen 
Published: May 2009

ObjectivesTo identify the expression of estrogen receptors in malignant minor salivary gland tumors of the sinonasal tract.Study DesignCase series with chart review.Subjects and MethodsA retrospective review of a pathology database identified 17 patients with malignant salivary gland tumors between December 1987 and January 2006. Clinicopathologic data were collected, and immunohistochemical staining for estrogen receptor α and β was performed.ResultsAmong these malignant tumors, adenoid cystic carcinoma was the predominant histologic type. In addition to epistaxis and nasal obstruction, the headache, facial, or ocular symptoms were also commonly noted in this cohort. Seventy‐five percent of cases of adenoid cystic carcinoma were positive for estrogen receptor α. In contrast, only 17 percent of cases of adenoid cystic carcinoma were positive for estrogen receptor β.ConclusionMalignant minor salivary gland tumors of the sinonasal tract are rare disease entities. In the present series, adenoid cystic carcinoma was the most common form of tumor, but the prognosis was poor. Most of the cases were positive for expression of estrogen receptor α, which suggests that hormone therapy may have a role in the management of certain minor salivary gland tumors of the paranasal sinus and nasal cavity.
GEORGE CANNING AND THE SPANISH QUESTION, SEPTEMBER 1822 TO MARCH 1823
Authors: YAMADA NORIHITO 
Published: May 2009

ABSTRACTHarold Temperley's The foreign policy of Canning, 1822–1827 (1925) has been widely acknowledged as the standard work on George Canning's foreign policy in 1822–7. Since its publication, historians have accepted its central theme: that the principal aim of Canning's foreign policy in 1822–7 was to destroy the post-1815 system of great-power concert in Europe. Temperley's book is remarkable for its consistency, and his account of Canning's policy with regard to the Spanish crisis of 1822–3 – that Canning's main concern was not to prevent foreign intervention in Spain, but to weaken the power and authority of the Concert of Europe by exploiting differences among the European allies over the question of Spain – is certainly consistent with its central theme. This article re-examines Canning's diplomacy on the Spanish question from the start of his second tenure in the foreign office to the French invasion of Spain, and contends that its reality fits neither Temperley's account of this particular subject nor his general thesis on Canning's foreign policy. A careful examination of Canning's early diplomacy indicates that its primary object was to prevent foreign military intervention in Spain, and that it was not influenced by a supposed dislike of great-power concert.