bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of electrical stimulation pattern on the force responses of paralyzed human quadriceps muscles
Authors: Scott Wayne B. , Lee Samuel C. K. , Johnston Therese E. , Binkley Jennifer , Binder‐MacLeod Stuart A.
Published: January 2007

Most studies examining the effect of electrical stimulation pattern on the force response of muscle have been done in able‐bodied persons. The purpose of this study was to examine the electrically elicited force responses of the paralyzed quadriceps femoris muscles of persons with spinal cord injuries (SCI) to see whether stimulation patterns that increase the force response in non‐paralyzed muscle will do so in paralyzed muscle. Thirteen subjects ranging in age from 11 to 24 years old with motor‐complete SCI were studied. Isometric muscle performance was tested using 6‐pulse constant‐frequency trains (CFTs), variable‐frequency trains (VFTs), and doublet‐frequency trains (DFTs) delivered at mean frequencies of 10, 20, 33, 50, and 100 HZ. In the non‐fatigued and fatigued condition, the VFT and DFT peak forces were greater than the CFT peak forces at 10 HZ. In addition, in the fatigued condition the 20‐HZ VFT peak forces were greater than the CFT peak forces, and there was a trend for the DFT peak forces to be greater than the CFT peak forces. In the non‐fatigued condition, the 33‐HZ and 50‐HZ DFT force–time integrals were greater than both the CFT and VFT force–time integrals. In the fatigued condition, there was no significant effect of train‐type on the force–time integrals. These results differ from those previously reported from studies using able‐bodied persons and indicate that findings from studies of the electrically elicited force responses of the muscles of able‐bodied persons do not apply to the paralyzed muscles of persons with SCI. Muscle Nerve, 2007
The 2D hydro‐mechanically coupled response of a rock mass with fractures via a mixed BEM–FEM technique
Authors: Fidelibus C.
Published: January 2007

This paper describes the essential features of a numerical technique for the simulation of the coupled fluid flow and deformation in a 2D assembly of poroelastic blocks and transmissive fractures. The boundary element method (BEM) is applied to each block to reduce Navier and diffusion equations to a set of integral equations involving block boundary terms, whereas a Galerkin weighted‐residuals finite element method (FEM) is applied to the fracture diffusion equations. In addition, fracture local equilibrium is rendered through spring‐like equations relating the stresses to the relative displacements of the fracture walls. A time‐marching process is implemented leading to an algebraic system where the right‐hand side vector is built based on the collected solutions of the previous time steps. The technique requires the meshing of the fracture network only. The accuracy of the results is adequate even with relatively coarse meshes without the resort to small time steps at the beginning of the simulation. It furnishes outputs that focus only on the salient features of the response. The efficiency of the technique is demonstrated through the illustration of the results of three examples. Copyright © 2007 John Wiley & Sons, Ltd.
The bridges of Königsberg—A historical perspective
Authors: Gribkovskaia Irina , Halskau Øyvind , Laporte Gilbert
Published: January 2007

The Bridges of Königsberg is one of the most famous problems in graph theory. In the summer of 2005, two of the authors visited Königsberg, now called Kaliningrad. This article provides geographical and historical information on Königsberg and its bridges, as well as updated information on the current day situation. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 49(3), 199–203 2007
Characterization of a corrinoid protein involved in the C1 metabolism of strict anaerobic bacterium Moorella thermoacetica
Authors: Das Amaresh , Fu Zheng‐Qing , Tempel Wolfram , Liu Zhi‐Jie , Chang Jessie , Chen Lirong , Lee Doowon , Zhou Weihong , Xu Hao , Shaw Neil , Rose John P. , Ljungdahl Lars G. , Wang Bi‐Cheng
Published: January 2007

The strict anaerobic, thermophilic bacterium Moorella thermoacetica metabolizes C1 compounds for example CO2/H2, CO, formate, and methanol into acetate via the Wood/Ljungdahl pathway. Some of the key steps in this pathway include the metabolism of the C1 compounds into the methyl group of methylenetetrahydrofolate (MTHF) and the transfer of the methyl group from MTHF to the methyl group of acetyl‐CoA catalyzed by methyltransferase, corrinoid protein and CO dehydrogenase/acetyl CoA synthase. Recently, we reported the crystallization of a 25 kDa methanol‐induced corrinoid protein from M. thermoacetica (Zhou et al., Acta Crystallogr F 2005; 61:537–540). In this study we analyzed the crystal structure of the 25 kDa protein and provide genetic and biochemical evidences supporting its role in the methanol metabolism of M. thermoacetia. The 25 kDa protein was encoded by orf1948 of contig 303 in the M. thermoacetica genome. It resembles similarity to MtaC the corrinoid protein of the methanol:CoM methyltransferase system of methane producing archaea. The latter enzyme system also contains two additional enzymes MtaA and MtaB. Homologs of MtaA and MtaB were found to be encoded by orf2632 of contig 303 and orf1949 of contig 309, respectively, in the M. thermoacetica genome. The orf1948 and orf1949 were co‐transcribed from a single polycistronic operon. Metal analysis and spectroscopic data confirmed the presence of cobalt and the corrinoid in the purified 25 kDa protein. High resolution X‐ray crystal structure of the purified 25 kDa protein revealed corrinoid as methylcobalamin with the imidazole of histidine as the α‐axial ligand replacing benziimidazole, suggesting base‐off configuration for the corrinoid. Methanol significantly activated the expression of the 25 kDa protein. Cyanide and nitrate inhibited methanol metabolism and suppressed the level of the 25 kDa protein. The results suggest a role of the 25 kDa protein in the methanol metabolism of M. thermoacetica. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Product or sum: comparative tests of Voigt, and product or sum of Gaussian and Lorentzian functions in the fitting of synthetic Voigt‐based X‐ray photoelectron spectra
Authors: Hesse R. , Streubel P. , Szargan R.
Published: January 2007

A comparative study for the fitting of X‐ray photoelectron spectra (XPS) using different model functions is presented. Synthetically generated test spectra using Gaussian/Lorentzian convolution and a real measured spectrum are fitted with the three commonly used models: product, sum and Gaussian/Lorentzian convolution functions. In these limited tests, it was found that the sum function is superior to the product function, particularly for low‐noise spectra. Copyright © 2007 John Wiley & Sons, Ltd.
Teachers' and prospective teachers' explanations of liquid‐state phenomena: A comparative study involving three European countries
Authors: Leite Laurinda , Mendoza José , Borsese Aldo
Published: January 2007

As contact with liquids occurs from an early stage in individuals' lives, children construct explanations for liquids and liquid‐state phenomena. These may differ from the accepted scientific explanations, interfere with formal teaching, and even persist until entry into higher education. The objective of this investigation is to compare student‐teachers' and in‐service science teachers' explanations for liquid‐state phenomena, in three European countries. Data were collected by means of a questionnaire applied to 195 Italian, Portuguese, and Spanish in‐service science teachers. Data analysis revealed poor performance among participants, showing low percentages of correct answers. In addition, no systematic differences were found between participants from the three countries, and teaching experience seems to minimize some of the conceptual difficulties showed by in‐service teachers. Globally, science education seems to have had a limited effect on student‐teachers' and in‐service science teachers' conceptions. We conclude that more attention should be paid to the liquid state in both initial and continuing teacher education programs so that teachers can understand more clearly liquid‐state phenomena and succeed in explaining them to their students. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 44: 349–374, 2007
Authentication traffics modeling and analysis in next generation wireless networks
Authors: Zhang Yan , Xiao Shaoqiu , Zhou Mingtuo , Fujise Masayuki
Published: January 2007

Access security is an indispensable component in the future generation wireless networks to enable the trusted communications. During the User Equipment (UE) access procedure, the authentication overhead analysis is able to provide insights in understanding the security management performance. To unify the model for analyzing the authentication traffics under different location management schemes, we introduce the concept location update inter‐arrival time. Furthermore, based on the UE's typical behavior, we propose a system model and define the metric number of User Authentication Request (UAR) in SGSN residence time to evaluate the authentication cost. Numerical results are illustrated to show the interaction between the parameters and the performance metrics. The sensitivity of call arrival process and the effects of location management schemes are also discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Nutrition in children with CRF and on dialysis
Authors: Rees Lesley , Shaw Vanessa
Published: January 2007

The objectives of this study are: (1) to understand the importance of nutrition in normal growth; (2) to review the methods of assessing nutritional status; (3) to review the dietary requirements of normal children throughout childhood, including protein, energy, vitamins and minerals; (4) to review recommendations for the nutritional requirements of children with chronic renal failure (CRF) and on dialysis; (5) to review reports of spontaneous nutritional intake in children with CRF and on dialysis; (6) to review the epidemiology of nutritional disturbances in renal disease, including height, weight and body composition; (7) to review the pathological mechanisms underlying poor appetite, abnormal metabolic rate and endocrine disturbances in renal disease; (8) to review the evidence for the benefit of dietetic input, dietary supplementation, nasogastric and gastrostomy feeds and intradialytic nutrition; (9) to review the effect of dialysis adequacy on nutrition; (10) to review the effect of nutrition on outcome.
Variables Affecting the Production of Standard Biodiesel
Authors: Mahajan Sonam , Konar Samir K. , Boocock David G. B.
Published: January 2007

Biodiesel is composed of fatty acid methyl esters, currently made from vegetable oils using basic catalysts. The oils must be reacted two or three times with methanol, in the presence of sodium methoxide to make products which meet the ASTM and European biodiesel standards. It is also believed that sodium hydroxide can never be used as the catalyst because it causes soap formation, which either lowers the yield or raises the acid number and makes product isolation difficult. Methods for producing standard biodiesel from low‐acid‐number soybean oil, in one chemical reaction using sodium hydroxide and a cosolvent, were recently reported. This study reports the effects of variables on the acid numbers and chemically bound glycerol contents of the products which led to the methods. These variables were the molar ratio of alcohol to oil, catalyst concentration, cosolvent volume, and reaction time. The alcohol‐to‐oil molar ratio must be at least 14, and the sodium hydroxide concentration should be at least 1.2 wt% (based on oil), to meet the necessary acid number and glycerol contents of the biodiesel. The volume of tetrahydrofuran cosolvent used must be 90–130% of that required to just create complete miscibility at the beginning of the reactions.
Endoscopic treatment of esthesioneuroblastoma: A minimally invasive approach combined with radiation therapy
Authors: Suriano Maria , De Vincentiis Marco , Colli Alessandro , Benfari Guido , Mascelli Alberto , Gallo Andrea
Published: January 2007

OBJECTIVE

In a retrospective analysis we discuss our experience in the treatment of olfactory neuroblastoma (ON), a rare tumor of the sinonasal tract.

STUDY DESIGN AND SETTING

Nine patients with olfactory neuroblastoma were treated at the Bolognini Hospital of Seriate and at the Department of Otolaryngology of “La Sapienza” University of Rome combining endoscopic surgery and postoperative radiation therapy. All patients were staged according to Kadish criteria. No chemotherapy was administered in any cases. Local radiation therapy was started postoperatively in all the cases.

RESULTS

All patients, over an average follow‐up which ranged from 26 through 60 months, are actually alive with non evidence of disease (NED).

CONCLUSIONS

Despite the short follow‐up in this small series of patients, we suggest endoscopic surgery combined with postoperative radiation therapy as an alternative to the conventional modalities of treatment for esthesioneuroblastoma in selected cases.

© 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.
Rhinitis medicamentosa: Electron microscopic changes of human nasal mucosa
Authors: Knipping Stephan , Holzhausen Hans Juergen , Goetze Gerrit , Riederer Andreas , Bloching Marc Boris
Published: January 2007

OBJECTIVE

Prolonged application of nasal vasoconstrictors causes rhinitis medicamentosa (RM). Nasal obstruction is induced by rebound swelling when the decongestive effect has disappeared. The aim of this study was to demonstrate ultrastructural changes in RM.

STUDY DESIGN AND SETTING

Tissue samples of inferior turbinates from 22 patients with RM and 10 patients without rhinitis were taken during nasal surgery. Ultrathin sections were investigated by using a transmission electron microscope (TEM).

RESULTS

The TEM findings revealed severe epithelial damages such as loss of ciliated cells. In the subepithelial region, the vascular endothelium showed gaps and ruptures of basal lamina.

CONCLUSION

RM is a drug‐induced damage of human nasal mucosa. Loss and destruction of ciliated epithelial cells are the morphologic correlation of the disturbed mucociliary clearance. In addition, vascular endothelium revealed ultrastructural changes. This could be caused by an increased vascular permeability with consecutive interstitial edema.

SIGNIFICANCE

This study demonstrated new morphological aspects of rhinitis medicamentosa.

© 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.
Extracts from The Cochrane Library: Antihistamines and/or decongestants for otitis media with effusion (OME) in children
Authors: Burton Martin J. , Rosenfeld Richard M.
Published: January 2007

The “Cochrane Corner” is a quarterly section in the Journal that highlights systematic reviews relevant to otolaryngology‐ head and neck surgery, with invited commentary to highlight implications for clinical decision making. This installment features a Cochrane Review entitled “Antihistamines and/or decongestants for otitis media with effusion (OME) in children,” which recommends against treatment because of no demonstrable benefits but significant potential for harm.

© 2007 American Academy of Otolaryngology‐Head and Neck Surgery Foundation. All rights reserved.
The effect of Egyptian honeybee propolis on the growth of Aspergillus versicolor and sterigmatocystin biosynthesis in Ras cheese
Authors: Aly Salwa A , Elewa Neimat A
Published: January 2007

Propolis is a natural product collected by honeybee workers. The product was tested for its antifungal effect against Aspergillus versicolor ATCC 12996 as well as biosynthesis of sterigmatocystin during ripening of Egyptian Ras cheese. The use of different concentrations of aqueous propolis extract 250, 500 and 1000 part per million (ppm) on the cheese surface was investigated. Mould growth and toxin production were completely inhibited at the highest concentration 1000 ppm, while the lower concentrations exhibited definite fungistatic activity during 90 days of ripening. Control cheese demonstrated that the amount of sterigmatocystin produced was proportional to the growth of Asp. versicolor during three months of ripening. It could be concluded that propolis concentration of 1000 ppm could prevent mould growth and sterigmatocystin production in Ras cheese. The economic as well as the public health importance of propolis as a natural preservative in cheese manufacture is discussed.
Alejandro Álvarez Situated: Subaltern Modernities and Modernisms that Subvert
Authors: LORCA ARNULF BECKER
Published: January 2007

Alejandro Álvarez's professional trajectory forces us to rethink the traditional modes of reading and writing the history of international law. Álvarez was central to the development of modern international law. He also happened to be a Latin American international lawyer. Should we interpret his work and life against the background of the intellectual and political history of Europe? Are the contexts that relate to the crisis of the European balance of power or the rise of nationalism the only ones that explain the emergence of a modern international legal discourse? This article situates Álvarez's scholarship within the intellectual, economic, and political history of Latin America. Interpreting Álvarez in the context of a genealogy of modernist Latin American thinkers illustrates the extent to which his work was part of a broader regional effort to appropriate European cultural artefacts in ways that granted them both a cosmopolitan and a distinctively Latin American character. Álvarez's modernism reinvented the meaning and uses of international law as a strategic foreign-policy tool in the interest of Latin American countries, a reinterpretation that contributed also to the construction of a Latin American identity and thought.
Prosecutor v. Naser Orić: The International Criminal Tribunal for the Former Yugoslavia Judgment of Srebrenica's Muslim Wartime Commander
Authors: BLUMENSTOCK TILMAN , PITTMAN WAYDE
Published: January 2007

In certain quarters of the former Yugoslavia, the ICTY judgment issued on 30 June 2006 in Prosecutor v. Naser Orić has been strongly criticized for meting out a two-year prison sentence to the Bosnian Muslim wartime commander of Srebrenica. After a short sketch of the factual background which the trial chamber considered to be the pivotal sentencing factor, this note focuses on the legal issues underlying his conviction for having failed to prevent the murder and cruel treatment of a number of Serb prisoners. In particular, the trial chamber's interpretation of the standard of ‘reason to know’ of these crimes deserves attention. The judgment also gave rise to other significant developments, such as the approach to repeated prosecutorial violations of its disclosure obligations and an important clarification regarding the scope and nature of crimes committed by subordinates of a superior.
9/11 as a European Event: the Novels
Authors: VERSLUYS KRISTIAAN
Published: January 2007

At the time of writing, more than 20 novels have been written that deal directly or indirectly with the events of 9/11. In broad outlines, they fall under four categories: the novel of recuperation, the novel of first-hand witnessing, the great New York novel, and the novel of the outsider. It is the last category of novels – written by non-Americans – that demonstrates the extent to which 11 September has penetrated deep into the European psyche and thus has become a European event. What is surprising is that the gap between the continents seems smaller in fiction than in politics. Even Luc Lang's onze septembre mon amour, a strident anti-American screed, is characterized by a sense of solidarity for the victims and for an alternative America, antithetical to the official one. In Frédéric Beigbeder's Windows on the World (a French novel with an English title), Europe and the US remain united in the overarching concept of the West, sharing a common destiny. In Ian McEwan's Saturday, finally, the events in the US have become part and parcel of the protagonist's existence, even though he lives thousands of miles away in the posh part of London.
Lost (and Found) in Translation: A Cultural History of Translators and Translating in Early Modern Europe
Authors: BURKE PETER
Published: January 2007

Attempting to combine cultural history with translation studies, this article examines translation between languages as a special case of a more general phenomenon, translation between cultures. It surveys printed translations made in Europe between 1500 and 1700, discussing which kinds of people translated which kinds of book from and into which languages. Particular attention is given to the reconstruction of the early modern ‘regime’ of translation, in other words the manner (free or literal, domesticating or ‘foreignizing’) in which translations were made.
Comparative Literature versus Translation Studies: Close Encounters of the Third Kind?
Authors: D'HULST LIEVEN
Published: January 2007

Translation has probably become the dominant means of communication between European literatures and, in consequence, may be considered a privileged object of study for Comparative Literature. Yet the complex nature of translation has hardly been recognized as an interlingual as well as an intralingual and intersemiotic operation. Translation between literatures covers two possible directions and should be labelled accordingly as either ‘intranslation’ or ‘extranslation’. In order to understand the complex roles all these translation forms have played during the history of European literatures and of European interliterary contacts, an explanatory model is needed that links the study of literatures and of interliterary relations: according to systems theory, literatures are to be understood as complex networks of relations that regulate both their internal structure and relations with other systems. Examples of translation figures and of translation flows help to show how translations contribute to the establishment of macro-European literary networks.
Carbon burial on river‐dominated continental shelves: Impact of historical changes in sediment loading adjacent to the Mississippi River
Authors: Allison Mead A. , Bianchi Thomas S. , McKee Brent A. , Sampere Troy P.
Published: January 2007

Seabed cores collected on the continental shelf adjacent to the Mississippi River show a direct temporal correlation between decreases in mass accumulation rate (factor of 2–3) and suspended sediment loads in the river. This mid 20th century decline is not apparent shelf‐wide due to sediment focusing and biological seabed mixing. Total organic carbon diagenetic loss rate across this sediment age interval is relatively uninterrupted when corrected for the non‐steady state mass flux. This suggests that organic carbon burial rates in oxic bottom water settings on river‐dominated continental margins are directly proportional to lithogenic flux. Variations in OM remineralization rates due to changes in the composition (marine vs. terrestrial) of the particulate OM flux at the sediment surface are a second‐order effect that cannot be distinguished in the bulk carbon sediment record at these oxic sites; although they may significantly alter the OM degradation‐induced CO2 flux to the overlying water column.
Tantalum carbonitride electrodes and the impact of interface chemistry on device characteristics
Authors: Schaeffer J. K. , Capasso C. , Gregory R. , Gilmer D. , Fonseca L. R. C. , Raymond M. , Happ C. , Kottke M. , Samavedam S. B. , Tobin P. J. , White B. E.
Published: January 2007

The intent of this research is to understand the role of interface chemistry on the effective work function and device characteristics of metal gate electrodes on hafnium dioxide (HfO2) gate dielectrics in metal oxide semiconductor field effect transistors. Since multiple factors, including crystal structure, preferred orientation, chemical composition, interface bonding, and reactions or interdiffusions, impact the effective work function, solid-solution carbonitrides of tantalum (TaCxN1−x) have been studied in an attempt to isolate the role of interface chemistry on the effective work function. Tantalum carbonitride films have been carefully deposited with similar Ta∕(C+N) ratios to understand how the substitution of N for C on the octahedral interstice in a face-centered-cubic tantalum lattice impacts device performance. Results indicate that the effective work function and device threshold voltage are reduced when the less electronegative carbon atom is substituted for the more electronegative nitrogen atom. This result is in qualitative agreement with the known relationship between metal electronegativity and effective work function and demonstrates the important role that sublattice elements in binary metal compounds have on the effective work function of the gate electrode.
Electron spin resonance study of as-deposited and annealed (HfO2)x(SiO2)1−x high-κ dielectrics on Si
Authors: Triplett B. B. , Chen P. T. , Nishi Y. , Kasai P. H. , Chambers J. J. , Colombo L.
Published: January 2007

Electron spin resonance measurements on 4 and 40nm thick (HfO2)0.6(SiO2)0.4 and (HfO2)0.4(SiO2)0.6 high-κ films on (100)Si wafers detected Pb0 and Pb1 defects at the dielectric/Si interface and verified their identities with g value mapping. Annealings of a 4nm thick (HfO2)0.6(SiO2)0.4 film in nitrogen at 800 and 1000°C monotonically lowered total interface states. In contrast, the same annealings monotonically increased the total interface states observed in 40nm thick films of both compositions. For the 4nm technologically relevant thickness, the annealed (HfO2)0.6(SiO2)0.4 composition on (100)Si had lower interface states than the (HfO2)0.4(SiO2)0.6 composition on (100)Si. After nitrogen annealing at 800°C, a third defect believed to be the EX, appears in larger quantities in the thicker 40nm films.
Reversible memory effects and acceptor states in pentacene-based organic thin-film transistors
Authors: Gu Gong , Kane Michael G. , Mau Siun-Chuon
Published: January 2007

Hysteresis is commonly seen in the current-voltage characteristics of organic thin-film transistors (OTFTs). In the absence of memory effects associated with the gate dielectric, the hysteresis in p-channel pentacene-based OTFTs, as measured in air and under illumination, was found to be dominated by trapped electrons in the semiconductor. The responsible acceptor-type traps have very long lifetimes. The immobile, previously stored negative charge requires extra holes to balance it, resulting in early establishment of the channel and extra drain current. This model is unique in that it explains the memory effect in terms of the electrostatic effect on the majority carrier population of trapped charge, opposite in sign to the majority carriers. The model is supported by drain current transient decay data. By studying the presence or absence of this effect and repeatedly measuring same devices on one substrate under various ambient and illumination conditions, we found that the responsible acceptor states are introduced by air exposure and illumination and that their formation, as well as the resulting memory effect, is reversible. Efforts were taken in the data analysis to separate the bias stress effect from the memory effect under study. The impact of this memory effect on OTFT measurement and application is discussed.
Shuttling of charge by a metallic sphere in viscous oil
Authors: Knutson C. R. , Edmond K. V. , Tuominen M. T. , Dinsmore A. D.
Published: January 2007

We measure the current transported by a microscopic metallic sphere shuttling charge through a fluid between two electrodes. Metallic spheres with diameters of 90–200μm were formed by emulsification of the alloy wood’s metal above its melting point in electrically insulating oil. Droplets of oil containing a single sphere in suspension were placed between two parallel electrodes. After a voltage was applied, the sphere conducted current through the oil by moving back and forth between the electrodes. The measured current was proportional to the voltage raised to a power that ranged between 3 for relatively high-viscosity silicone oil and slightly above 2 for hexadecane. The magnitude of the current and the frequency of the shuttling are well described across a broad range of parameters by a model that includes dissipation in the fluid at low Reynolds number. Discontinuous jumps in the conductance arise from the finite inertia of the particle, which leads to recoil from the electrodes at Stokes number of order ten.
Conductivity profile determination by eddy current for shot-peened superalloy surfaces toward residual stress assessment
Authors: Shen Y. , Lee C. , Lo C. C. H. , Nakagawa N. , Frishman A. M.
Published: January 2007

This paper demonstrates a swept high frequency eddy current (SHFEC) methodology that can determine near-surface conductivity deviation profiles of shot-peened superalloy surfaces, from which residual stress state can be assessed nondestructively. Our methodology is built around a laboratory-grade SHFEC hardware and a model-based SHFEC data inversion software, both described in this article. For the demonstration, a series of shot-peened Inconel 718 block specimens is prepared and examined by the proposed SHFEC inversion technique. The conductivity depth profiles of the samples under various shot peening intensities have been obtained by the inversion. Several sensitivity and consistency test results are given to support the reliability of the inverted conductivity profiles. The extreme near-surface regions (10–20μm) of the shot-peened surfaces are also examined by various microstructural characterization methods such as scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray diffraction, to examine our inversion results microscopically.
Magnetic and magnetoresistive properties of NiFe/Au/Co/Au multilayers with perpendicular anisotropy of Co layers
Authors: Urbaniak M. , Stobiecki F. , Szymański B. , Ehresmann A. , Maziewski A. , Tekielak M.
Published: January 2007

The giant magnetoresistance (GMR), magnetization reversal, and domain structure of magnetron sputtered spin valve [NiFe/Au/Co/Au]N multilayers consisting of ferromagnetic layers with alternating in-plane (NiFe) and out-of-plane (Co) magnetic anisotropy has been investigated. For 0.4<tCo<1.2 nm GMR dependencies characterized by a linear and almost nonhysteretic dependence of resistance on the magnetic field were found. Within the hysteretic range of the magnetization reversal of the Co layers, for N>3, the neighboring magnetic layers were observed to be coupled. This coupling is of magnetostatic origin. The effective coupling field, estimated from GMR dependencies, is of the order of 100 kA/m. Micromagnetic simulations confirm that the domain structure of Co layers influences the behavior of NiFe layers.
Substitution effects on the ferroelectric properties of BiFeO3 thin films prepared by chemical solution deposition
Authors: Kim Jong Kuk , Kim Sang Su , Kim Won-Jeong , Bhalla Amar S.
Published: January 2007

Ferroelectric properties of Cr-substituted BiFeO3 (BFCr) and Pb-cosubstituted BFCr films prepared by a chemical solution deposition method and annealed at 550°C in nitrogen have been studied. X-ray diffraction measurements revealed that the thin films were composed of a rhombohedrally distorted perovskite structure without secondary phases. The 5mol% Pb-cosubstituted BFCr films appeared to have superior ferroelectric properties to those of other BFCr films prepared by the same conditions. The remanent polarization (Pr) and the coercive field (Ec) of the 5mol% Pb-cosubstituted BFCr film were 62μC∕cm2 and 235kV∕cm, respectively, with a maximum applied field of 712kV∕cm. In addition, the film exhibited a fatigue-free behavior up to 1.45×1010 read/write cycles.
Total cross section exceeds transport cross section for quantum scattering from hard bodies at low and high wave numbers
Authors: De Roeck W. , Lakshtanov E. L.
Published: January 2007

The quantum scattering by smooth bodies is considered for small and large values of kd, with k the wave number and d the scale of the body. In both regimes, we prove that the forward scattering exceeds the backscattering. For high k, we need to assume that the body is strictly convex.
Fabrication and magnetic properties of FeCo alloy nanotube array
Authors: Li F. S. , Zhou D. , Wang T. , Wang Y. , Song L. J. , Xu C. T.
Published: January 2007

An array of FeCo nanotubes has been fabricated in the pores of porous anodic aluminum oxide templates. The morphology, structure, and composition of the nanotube array were characterized by transmission electron microscopy, x-ray diffraction, and atomic absorption spectroscopy. Magnetostatic energy analysis and transmission Mössbauer spectroscopy measurements were used to investigate the distribution of magnetic moments in nanotubes. Magnetization hysteresis loops indicate that, due to the unique shape of the nanotube, the nanotube array could be magnetized more easily by the field that is applied parallel to the axis of nanotubes.
An energy balance approach of the dynamics of drop impact on a solid surface
Authors: Attané P. , Girard F. , Morin V.
Published: January 2007

The description of physical mechanisms involved in the impact of a drop upon a dry, partially wettable substrate is still a matter of debate. One way to analyze the balance of these mechanisms is the development of an analytical one-dimensional (1D) model based upon the energy equation. The assimilation of the drop to a cylinder allows a reduction of the energy equation to a second-order differential equation. This paper proposes a semi-empirical description of viscous dissipation taking into account the rolling motion near the contact line. The dissipation due to the rolling motion is added to the calculated dissipation in the core of the droplet. We compare our model to previous ones using a large set of literature data covering a wide range of viscosity, velocity impact, and equilibrium contact angle values. The new dissipation description proposed is shown to supersede those described in previous 1D models. Our model closely predicts the maximum spread factor and the time at which it is obtained on the whole range of Ohnesorge and Weber numbers considered. It also distinguishes between deposition with a steady variation in the wetted area from deposition with advancing and receding phases. The main limitations of the model lie in its inability to reproduce the spread factor at the very beginning of the impact and the rebounding observed after a receding phase for very high values of the equilibrium contact angle.
Cold plasma brush generated at atmospheric pressure
Authors: Duan Yixiang , Huang C. , Yu Q. S.
Published: January 2007

A cold plasma brush is generated at atmospheric pressure with low power consumption in the level of several watts (as low as 4W) up to tens of watts (up to 45W). The plasma can be ignited and sustained in both continuous and pulsed modes with different plasma gases such as argon or helium, but argon was selected as a primary gas for use in this work. The brush-shaped plasma is formed and extended outside of the discharge chamber with typical dimension of 10–15mm in width and less than 1.0mm in thickness, which are adjustable by changing the discharge chamber design and operating conditions. The brush-shaped plasma provides some unique features and distinct nonequilibrium plasma characteristics. Temperature measurements using a thermocouple thermometer showed that the gas phase temperatures of the plasma brush are close to room temperature (as low as 42°C) when running with a relatively high gas flow rate of about 3500ml∕min. For an argon plasma brush, the operating voltage from less than 500V to about 2500V was tested, with an argon gas flow rate varied from less than 1000to3500ml∕min. The cold plasma brush can most efficiently use the discharge power as well as the plasma gas for material and surface treatment. The very low power consumption of such an atmospheric argon plasma brush provides many unique advantages in practical applications including battery-powered operation and use in large-scale applications. Several polymer film samples were tested for surface treatment with the newly developed device, and successful changes of the wettability property from hydrophobic to hydrophilic were achieved within a few seconds.
High-order electron-correlation methods with scalar relativistic and spin-orbit corrections
Authors: Hirata So , Yanai Takeshi , Harrison Robert J. , Kamiya Muneaki , Fan Peng-Dong
Published: January 2007

An assortment of computer-generated, parallel-executable programs of ab initio electron-correlation methods has been fitted with the ability to use relativistic reference wave functions. This has been done on the basis of scalar relativistic and spin-orbit effective potentials and by allowing the computer-generated programs to handle complex-valued, spinless orbitals determined by these potentials. The electron-correlation methods that benefit from this extension are high-order coupled-cluster methods (up to quadruple excitation operators) for closed- and open-shell species, coupled-cluster methods for excited and ionized states (up to quadruples), second-order perturbation corrections to coupled-cluster methods (up to triples), high-order perturbation corrections to configuration-interaction singles, and active-space (multireference) coupled-cluster methods for the ground, excited, and ionized states (up to active-space quadruples). A subset of these methods is used jointly such that the dynamical correlation energies and scalar relativistic effects are computed by a lower-order electron-correlation method with more extensive basis sets and all-electron relativistic treatment, whereas the nondynamical correlation energies and spin-orbit effects are treated by a higher-order electron-correlation method with smaller basis sets and relativistic effective potentials. The authors demonstrate the utility and efficiency of this composite scheme in chemical simulation wherein the consideration of spin-orbit effects is essential: ionization energies of rare gases, spectroscopic constants of protonated rare gases, and photoelectron spectra of hydrogen halides.
Cross-talk correction in atomic force microscopy
Authors: Hoffmann Á. , Jungk T. , Soergel E.
Published: January 2007

Commercial atomic force microscopes usually use a position-sensitive photodiode to detect the motion of the cantilever via laser beam deflection. This readout technique makes it possible to measure bending and torsion of the cantilever separately. A slight angle between the orientation of the photodiode and the plane of the readout laser beam, however, causes false signals in both readout channels. This cross-talk may lead to misinterpretation of the acquired data. We demonstrate this fault with images recorded in contact mode on periodically poled ferroelectric crystals and present a simple electronic circuit to compensate for it. This circuit can correct for cross-talk with a bandwidth of ∼1MHz suppressing the the false signal to ⪡1%.
Metal-organic vapor phase epitaxy and properties of AlInN in the whole compositional range
Authors: Hums C. , Bläsing J. , Dadgar A. , Diez A. , Hempel T. , Christen J. , Krost A. , Lorenz K. , Alves E.
Published: January 2007

The authors present a detailed study of Al1−xInxN layers covering the whole composition range of 0.09<x<1. All layers were grown on GaN on Si(111) templates using metal-organic vapor phase epitaxy. For 0.13<x<0.32 samples grow fully strained and without phase separation. At higher In concentrations, the crystalline quality starts to deteriorate and a transition to three-dimensional growth is observed. A comparison of their experimental data with theoretically predicted phase diagrams reveals that biaxial strain increases the stability of the alloy.
Phenomenological theory of the nematic to lamellar phase transition in lyotropic liquid crystals
Authors: Mukherjee Prabir K. , Bhattacharya Joydeep
Published: January 2007

A phenomenological theory is presented to describe the nematic to lamellar phase transition in lyotropic liquid crystals. The problem of the first or second order transition is explored by means of the variation of the surfactant concentration. The possibility of the tricritical point at the nematic to lamellar phase transition is discussed in a phenomenological way. The influence of the electrolyte on this transition is also discussed by varying the coupling between the electrolyte concentration variables and the order parameters. The theoretical prediction is found to be in good qualitative agreement with experimental results.
Nonlinear low noise particle-in-cell simulations of electron temperature gradient driven turbulence
Authors: Bottino A. , Peeters A. G. , Hatzky R. , Jolliet S. , McMillan B. F. , Tran T. M. , Villard L.
Published: January 2007

In this Letter, it is shown that global, nonlinear, particle-in-cell (PIC) simulations of electron temperature driven turbulence recover the same level of transport as flux-tube codes when the level of statistical noise, associated with the PIC discretization, is sufficiently small. An efficient measure of the signal-to-noise ratio, applicable to every PIC code, is introduced. This diagnostic provides a direct measure of the quality of PIC simulations and allows for the validation of analytical estimates of the numerical noise. Global simulations for values of ρe*<1∕450 (normalized electron gyroradius) show no evidence of a gyro-Bohm scaling.
Shaping of microwave pulses using phase-sensitive spin-wave amplifier
Authors: Serga A. A. , Schneider T. , Hillebrands B. , Kostylev M. P. , Slavin A. N.
Published: January 2007

It is shown that by introducing a phase shift between the signal microwave pulse and the double-frequency pumping pulse in a parametric spin-wave amplifier it is possible to effectively control the shape of the output microwave pulse. The observed pulse shaping results from the interference of a signal pulse with copropagating “idle” pulse parametrically excited by pumping and with the parasitic standing spin waves amplified by pumping from the thermal level. This interpretation is supported by the numerical simulation and by the results of a time-resolved Brillouin light scattering experiment.
Working principle of voltage controlled differential magnetic field sensor
Authors: Kim Hyeoungwoo , Islam Rashed A. , Priya Shashank
Published: January 2007

In this letter the authors present the experimental data illustrating the working mechanism of the high sensitivity differential magnetic field sensor. Further, the authors report for the data showing the possibility for realizing a voltage controlled magnetic field. The sensor works on the following principle. A constant voltage is applied to the ring section of the sensor at the resonance frequency which induces magnetic field in the dot section. If an external magnetic object is brought in the vicinity of the dot section, then the resulting differential magnetic field induces change in the voltage gain due to magnetoelectric effect.
Elucidation of the electron injection mechanism of evaporated cesium carbonate cathode interlayer for organic light-emitting diodes
Authors: Li Yang , Zhang De-Qiang , Duan Lian , Zhang Rui , Wang Li-Duo , Qiu Yong
Published: January 2007

Vacuum evaporated Cs2CO3 has been proven to be an efficient electron injection material for organic light-emitting diodes. In our study, an improved quartz crystal microbalance method has been adopted to investigate the electron injection mechanism of evaporated Cs2CO3. It is concluded that Cs2CO3 decomposes to metallic cesium during thermal evaporation and the thin layer of metallic cesium that is deposited onto the organic layer is responsible for the enhanced electron injection. The metallic cesium mechanism reveals that the function of the Cs2CO3 interlayer is independent of the cathode metal, which has also been verified by our experiments.
Atomic force nanolithography of InP for site control growth of InAs nanostructures
Authors: Fonseca-Filho H. D. , Prioli R. , Pires M. P. , Lopes A. S. , Souza P. L. , Ponce F. A.
Published: January 2007

A combination of atomic force nanolithography and metal organic vapor phase epitaxy has been used to control the nucleation of InAs nanostructures on InP substrates. Pits with controlled width and depth were produced on InP with the use of atomic force nanolithography. The number of nucleated nanostructures depends on the applied force and is independent of the geometry of the pits. Study shows that the density of crystalline defects introduced by nanoindentation is responsible for the number of nucleated nanostructures.
Negative differential resistance in La0.67Ca0.33MnO3−δ∕Nb–SrTiO3 p-n junction
Authors: Xiao Y. S. , Zhang X. P. , Zhao Y. G.
Published: January 2007

La 0.67 Ca 0.33 Mn O 3 − δ ∕ Nb – Sr Ti O 3  p-n junction was fabricated by pulsed laser deposition. The I-V curves of this junction show rectifying behavior. Negative differential resistance (NDR) was observed at low temperatures under large bias voltages and NDR becomes more remarkable with decreasing temperature. In addition to NDR, the I-V curves also show remarkable hysteresis. The results were explained in terms of the effect of local Joule heating on the phase separation in the strained ultrathin La0.67Ca0.33MnO3−δ thin film.
Frequency dependence of the nonlinear response in YBa2Cu3O7−x transmission lines
Authors: Mateu Jordi , Booth James C. , Moeckly Brian H.
Published: January 2007

The authors evaluate the frequency dependence of the nonlinear response in high-temperature superconductor YBa2Cu3O7−x thin films by simultaneously measuring the nonlinear intermodulation products and harmonic generation in broadband superconducting transmission lines at 76K. The frequencies of the two-tone incident signal are set to produce spurious signals from 1to21GHz. They extract a nonlinear term ∣ΔR2+jωΔL2∣ by applying a model of spurious signal generation in superconducting transmission lines to their measurement results. They found that this nonlinear term follows a linear dependence on frequency, indicating a dominant contribution of the nonlinear inductance ΔL2 over the nonlinear resistance ΔR2, (ωΔL2⪢ΔR2), for the superconducting nonlinear response.
Effects of thermal nitrided gate-oxide thickness on 4H silicon-carbide-based metal-oxide-semiconductor characteristics
Authors: Cheong Kuan Yew , Bahng Wook , Kim Nam-Kyun
Published: January 2007

The effects of thermal nitrided gate-oxide thickness on n-type 4H silicon-carbide-based metal-oxide-semiconductor characteristics have been reported. Seven different thicknesses of oxide (tox), ranging from 2to20nm, have been investigated. It has been shown that effective oxide charge (Qeff) and total interface-trap density (Nit) have demonstrated a cyclic trend as tox is increased. These observations have been explained in the letter. Correlations of Qeff and Nit with oxide breakdown field and current transport mechanism in these oxides have also been established and explained.
Subwavelength waveguide for visible light
Authors: Rybczynski J. , Kempa K. , Herczynski A. , Wang Y. , Naughton M. J. , Ren Z. F. , Huang Z. P. , Cai D. , Giersig M.
Published: January 2007

The authors demonstrate transmission of visible light through metallic coaxial nanostructures many wavelengths in length, with coaxial electrode spacing much less than a wavelength. Since the light frequency is well below the plasma resonance in the metal of the electrodes, the propagating mode reduces to the well-known transverse electromagnetic mode of a coaxial waveguide. They have thus achieved a faithful analog of the conventional coaxial cable for visible light.