bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection and treatment of akathisia in advanced cancer patients during adjuvant analgesic therapy with tricyclic antidepressants: Case reports and review of the literature
Authors: Onishi Hideki , Yamamoto Wataru , Wada Makoto , Nishida Tomomi , Wada Mei , Sunagawa Yu , Miya Toshimichi , Kawanishi Chiaki , Narabayashi Masaru , Sasaki Yasutsuna
Published: October 2007

Objective:

There is substantial evidence that tricyclic antidepressants are effective in the management of chronic pain, including cancer pain. In oncological settings, these agents are used as adjuvant analgesic drugs. However, cases of akathisia due to tricyclic antidepressants used as adjuvant analgesic therapy have not previously been reported.

Case reports:

Two cancer patients experiencing chronic pain who were refractory to nonsteroidal anti-inflammatory drugs and opioids were prescribed amoxapine as an adjuvant analgesic therapy for neuropathic pain. These patients developed inner restlessness and restless physical movements after amoxapine was prescribed. Although symptoms were atypical, akathisia was suspected and discontinuation of amoxapine resolved the symptoms.

Results and significance of results:

Akathisia should be considered in patients receiving adjuvant analgesic therapy with tricyclic antidepressants. Early detection and appropriate treatment will relieve this distressing symptom. Restless movements involving parts of the body other than the legs may be the clue to the diagnosis.
Beam‐plasma interaction in randomly inhomogeneous plasmas and statistical properties of small‐amplitude Langmuir waves in the solar wind and electron foreshock
Authors: Krasnoselskikh V. V. , Lobzin V. V. , Musatenko K. , Soucek J. , Pickett J. S. , Cairns I. H.
Published: October 2007

A numerical model for wave propagation in an unstable plasma with inhomogeneities is developed. This model describes the linear interaction of Langmuir wave packets with an electron beam and takes into account the angular diffusion of the wave vector due to wave scattering on small‐amplitude density fluctuations, as well as suppression of the instability caused by the removal of the wave from the resonance with particles during crossing density perturbations of relatively large amplitude. Using this model, the evolution of the wave packets in inhomogeneous plasmas with an electron beam is studied. To analyze data obtained both in space experiments and numerical modeling, a Pearson technique was used to classify the spectral density distributions. It was shown that both experimental distributions obtained within the Earth's foreshock aboard the CLUSTER spacecraft and model distributions for the logarithm of wave intensity belong to Pearson type IV rather than normal. The main reason for deviations of empirical distributions from the normal one is that the effective number of regions where the waves grow is not very large and, as a consequence, the central limit theorem fails to be true under the typical conditions for the Earth's electron foreshock. For large amplitudes, it is suggested that power law tails can result from variations of wave amplitudes due to changes of group velocity in the inhomogeneous plasma, in particular due to reflection of waves from inhomogeneities.
Simulation of intense organized convective precipitation observed during the Arabian Sea Monsoon Experiment (ARMEX)
Authors: Das Someshwar , Ashrit R. , Moncrieff Mitchell W. , Das Gupta Munmun , Dudhia Jimy , Liu C. , Kalsi S. R.
Published: October 2007

We examine a deep precipitating system that formed over the west coast of India during 26–28 June 2002 producing heavy rainfall of 2–61 cm day−1. The system developed into a well‐marked low pressure area due to interaction between an eastward moving westerly trough and a westward moving monsoon low. We used the PSU/NCAR Mesoscale Model (MM5) to make 10‐day interactively nested simulations at 90, 30, and 10 km grid‐resolutions. We used observations from a special data set collected during an Arabian Sea Monsoon Experiment (ARMEX) conducted June–August, 2002. Nudging the observations produced a balanced atmosphere which, in turn, matched the location of vortex with cloud clusters observed from satellite. The simulated rainfall corresponded well with observations. We then use the simulated fields as forcing and boundary conditions for MM5 run in cloud‐system resolving mode at 2 km grid‐resolution to detail cloud‐clusters embedded within the monsoon disturbance. We examined the sensitivity to different physical parameterizations and also the effect of continuous nudging four dimensional data assimilation (FDDA) on the rainfall forecasts. While the simulation of the convective event improved with certain combinations of physical parameterizations, the rainfall was not forecasted at the correct location, no matter which parameterization was used, unless continuous FDDA was performed in all domains throughout the integrations. Finally, cloud‐cluster properties of the cloud‐system resolving simulations were compared with observations.
Magmatic fissures and their systems in Iceland: A tectonomagmatic model
Authors: Tentler Tatiana , Temperley Stephen
Published: October 2007

Volcanic systems in Iceland comprise a central volcano linked to magmatic fissures, whose subsurface architecture remains enigmatic. The surface dimensions and trends of active fissures show their spatial relation with fault systems. Structure of the Fremri‐Namur and Hengill volcanic systems was analyzed. The linear vent arrays marking recent fissures are tightly bound by vertical segmented faults, while normal faults accommodating extension are common on the flanks of the fissure swarm. Evidence of normal frictional slip on the fissure‐bounded faults suggests that failure occurred in response to subsidence with subsequent dilation. This is supported by inward tilting of strata adjacent to faults compatible with a downsag phase. We propose that magmatic fissures have vertical feeders with lateral offshoots extending along the rift zone. Their inflation/deflation during an eruptive cycle causes subsidence. Such magmatically generated faults can be subsequently modified by tectonic extension.
Compound effects of Antarctic sea ice on atmospheric pCO2 change during glacial–interglacial cycle
Authors: Kurahashi‐Nakamura T. , Abe‐Ouchi A. , Yamanaka Y. , Misumi K.
Published: October 2007

The cause of low atmospheric CO2 concentrations during the Last Glacial Maximum (LGM) is important for understanding the role of the carbon cycle in climatic variation. We used an ocean general circulation model, coupled with a biogeochemical model, to examine the effect of sea‐ice expansion in the Southern Ocean on atmospheric CO2 concentration. We newly considered a possible additional effect of sea‐ice expansion in reducing biological activity as well as the effect of reduced gas‐exchange. We propose that the new effect might have had an opposite operation and canceled the gas‐exchange effect. Although there are some uncertainties arising from the absence of explicit sea‐ice model in this study, these results suggest that sea‐ice expansion might be far from the principal mechanism for low CO2 concentration during the LGM.
Three‐dimensional distributions of S wave reflectors in the source region of the 2000 Western Tottori Earthquake
Authors: Doi Issei , Nishigami Kin'ya
Published: October 2007

We conducted a reflection analysis of the aftershock waveforms in the source region of the 2000 Western Tottori Earthquake. We obtained three‐dimensional distributions of S wave reflectors in the source region by using ∼9000 waveform traces. In the cross‐section projected along the mainshock fault plane, we found three major reflection zones at depths of 15–25 km, 30–40 km and 50–60 km. The first and second are thought to correspond to the Conrad and the Moho discontinuities. The depth of these reflective zones seems to change along the fault direction. Also, cross‐sections perpendicular to the fault plane show that the strengths of the reflected waves are different between the two sides of the fault plane. This result suggests that the mainshock fault plane is located at the boundary of medium properties and its near‐vertical downward extension in the lower crust.
Recent spatial and temporal variability and trends of sunshine duration over the Iberian Peninsula from a homogenized data set
Authors: Sanchez‐Lorenzo Arturo , Brunetti Michele , Calbó Josep , Martin‐Vide Javier
Published: October 2007

This paper describes the construction of a new data set of sunshine duration over the Iberian Peninsula (IP), based upon 72 monthly instrumental series covering the 1931–2004 period. Particular emphasis is placed upon the quality control, gap filling, and homogenization procedures. We also produced a gridded version (1° × 1° resolution, latitude, and longitude) of the homogenized data set covering the whole IP with 84 cells. We subsequently analyzed sunshine duration data in search of temporal variability, long‐term trends, and spatial differences over the IP. The analyses were carried out on the mean series calculated for the whole IP and for four subregions, at annual, seasonal, and monthly resolution. We defined the subregions using a principal component analysis applied to the sunshine duration data. The temporal evolution of the mean annual series for the whole IP shows a decrease in sunshine duration from the 1950s to the early 1980s, followed by a positive trend up to the end of the 20th century, which matches the “global dimming” and the subsequent and recent “brightening” described for other regions in international scientific literature. The most interesting seasonal significant trend for the IP series was found for summer (−0.9% per decade, over the 1951–2004 period); this trend is influenced by the months of July and August in two subregions. In addition, important trends ranging from +2.8 to +3.8% per decade were observed for the March series for all Mediterranean climate subregions.
Dobson total ozone series of Oxford: Reevaluation and applications
Authors: Vogler C. , Brönnimann S. , Staehelin J. , Griffin R. E. M.
Published: October 2007

We have reevaluated the original total ozone measurements made in Oxford between 1924 and 1957, with a view to extending backward in time the existing total ozone series from 1957 to 1975. The Oxford measurements are the oldest Dobson observations in the world. Their prime importance, when coupled with the series from Arosa (since 1926) and Tromsø (since 1935), is for increasing basic understanding of stratospheric ozone and dynamics, while in relation to studies of the recent ozone depletion they constitute a baseline of considerable (and unique) significance and value. However, the reevaluation was made difficult on account of changes to the instruments and wavelengths as the early data collection methods evolved, while unknowns due to the influence of aerosols and the possible presence of dioxides of sulphur and nitrogen created additional problems. Our reevaluation was based on statistical procedures (comparisons with meteorological upper air data and ozone series from Arosa) and also on corrections suggested by Dobson himself. The comparisons demonstrate that the data are internally consistent and of good quality. Nevertheless, as post‐1957 data were not assessed in this study, the series cannot be recommended at present for trend analysis, though the series can be used for climatological studies. By supplementing the Oxford data with other existing series, we present a European total ozone climatology for 1924–1939, 1950–1965, and 1988–2000 and analyze the data with respect to variables measuring the strength and the temperature of the polar vortex.
Feedbacks between fires and wind erosion in heterogeneous arid lands
Authors: Ravi Sujith , D'Odorico Paolo , Zobeck Ted M. , Over Thomas M. , Collins Scott L.
Published: October 2007

Shrub encroachment, a widespread phenomenon in arid landscapes, creates “islands of fertility” in degraded systems as wind erosion removes nutrient‐rich soil from intercanopy areas and deposits it in nearby shrub‐vegetated patches. These islands of fertility generally are considered to be irreversible. Recently, fire has been observed to alter this pattern of resource heterogeneity through the redistribution of nutrients from the fertile islands of burnt shrubs to the surrounding bare soil areas. Despite the recognized relevance of both fires and wind erosion to the structure and function of arid ecosystems, the interactions between these two processes remains poorly understood. This study tests the hypothesis that fire‐induced soil hydrophobicity developing in the soils beneath burned shrubs enhances soil erodibility by weakening the interparticle wet‐bonding forces. To test this hypothesis, the effects of grass and shrub fires on changes in soil erodibility and on the intensity of fire‐induced soil water repellency are compared at both the field and patch scales in heterogeneous arid landscapes. Higher water repellency was observed in conjunction with a stronger decrease in wind erosion threshold velocity around the shrubs than in grass‐dominated patches affected by fire, while neither water repellency nor changes in threshold velocity was noticed in the bare soil interspaces. Thus, fires are found to induce soil hydrophobicity and to consequently enhance soil erodibility in shrub‐vegetated islands of fertility. These processes create temporally dynamic islands of fertility and contribute to a decrease in resource heterogeneity in aridland ecosystems following fire.
Population level functional diversity in a microbial community revealed by comparative genomic and metagenomic analyses
Authors: Bhaya Devaki , Grossman Arthur R , Steunou Anne-Soisig , Khuri Natalia , Cohan Frederick M , Hamamura Natsuko , Melendrez Melanie C , Bateson Mary M , Ward David M , Heidelberg John F
Published: October 2007

In microbial mat communities of Yellowstone hot springs, ribosomal RNA (rRNA) sequence diversity patterns indicate the presence of closely related bacterial populations along environmental gradients of temperature and light. To identify the functional bases for adaptation, we sequenced the genomes of two cyanobacterial (Synechococcus OS-A and OS-B′) isolates representing ecologically distinct populations that dominate at different temperatures and are major primary producers in the mat. There was a marked lack of conserved large-scale gene order between the two Synechococcus genomes, indicative of extensive genomic rearrangements. Comparative genomic analyses showed that the isolates shared a large fraction of their gene content at high identity, yet, differences in phosphate and nitrogen utilization pathways indicated that they have adapted differentially to nutrient fluxes, possibly by the acquisition of genes by lateral gene transfer or their loss in certain populations. Comparisons of the Synechococcus genomes to metagenomic sequences derived from mats where these Synechococcus stains were originally isolated, revealed new facets of microbial diversity. First, Synechococcus populations at the lower temperature regions of the mat showed greater sequence diversity than those at high temperatures, consistent with a greater number of ecologically distinct populations at the lower temperature. Second, we found evidence of a specialized population that is apparently very closely related to Synechococcus OS-B′, but contains genes that function in the uptake of reduced ferrous iron. In situ expression studies demonstrated that these genes are differentially expressed over the diel cycle, with highest expression when the mats are anoxic and iron may be in the reduced state. Genomic information from these mat-specific isolates and metagenomic information can be coupled to detect naturally occurring populations that are associated with different functionalities, not always represented by isolates, but which may nevertheless be important for niche partitioning and the establishment of microbial community structure.
Visualization Summit 2007: Ten Research Goals for 2010
Authors: Burkhard Remo Aslak , Andrienko Gennady , Andrienko Natalia , Dykes Jason , Koutamanis Alexander , Kienreich Wolfgang , Phaal Robert , Blackwell Alan , Eppler Martin , Huang Jeffrey , Meagher Mark , Grün Armin , Lang Silke , Perrin Daniel , Weber Wibke , Vande Moere Andrew , Herr Bruce , Börner Katy , Fekete Jean-Daniel , Brodbeck Dominique
Published: October 2007

At the first international Visualization Summit, more than 100 international researchers and practitioners defined and assessed nine original and important research goals in the context of Visualization Science, and proposed methods for achieving these goals by 2010. The synthesis of the whole event is presented in the 10th research goal. This article contributes a building block for systemizing visualization research by proposing mutually elaborated research goals with defined milestones. Such a consensus on where to go together is only one step toward establishing visualization science in the long-term perspective as a discipline with comparable relevance to chemistry, mathematics, language, or history. First, this article introduces the conference setting. Second, it describes the research goals and findings from the nine workshops. Third, a survey among 62 participants about the originality and importance of each research goal is presented and discussed. Finally, the article presents a synthesis of the nine research goals in the form of a 10th research goal, namely ‘Visualizing Future Cities’. The article is relevant for visualization researchers, trend scouts, research programme directors who define the topics that get funds.
Temperature dependence of the microwave conductivity of a YBCuO film in the normal state
Authors: Gubin A. I. , Cherpak N. T. , Lavrinovich A. A. , Oganisian K. V.
Published: October 2007

The results of an experimental study of the fluctuation conductivity of an optimally doped YBa2Cu3O7−δ epitaxial film are presented. The results were obtained from measurements of the complex reflection coefficient of the sample at grazing incidence according to a method developed and implemented by the authors in the millimeter wavelength range. The results demonstrate good agreement with a theoretical model constructed in the framework of Gaussian theory for a frequency-limited fluctuational 2D microwave conductivity in the temperature interval 93–120K.
Temperature features of the magnetic interactions in manganese stannide
Authors: Virchenko V. A. , Tkachenko T. M. , Thomas M. F.
Published: October 2007

The features of the magnetic interactions in manganese stannide Mn1.66Fe0.02Sn with a structure of the B82 type are investigated on the basis of Mössbauer-effect measurements on the iron and tin atoms. The Curie temperature of this compound according to the Fe57 data is TC=265K, while for Sn119 it is TC=250K; both of these are higher than the value of TC determined by the Faraday method (240K). The participation of the tin atoms in the magnetic exchange interaction in MnII–Sn–MnII chains is confirmed. It is shown that effectively only three of the five manganese atoms occupying the trigonal–bipyramidal MnII positions nearest to a tin atom have any influence on the magnetic interactions at the tin nucleus. The magnetic fields at the nuclei of the manganese atoms in the trigonal–bipyramidal positions in MnII–Sn–MnII chains are significantly (2–2.5 times) larger than the field at the nuclei of the manganese atoms in the octahedral positions in MnI–MnI.
Step-like anomaly of the magnetic susceptibility in crystals with degenerate electronic energy bands
Authors: Mikitik G. P.
Published: October 2007

It is shown that the dependence of the magnetic susceptibility of electrons in a crystal on their chemical potential can take the form of a sharp step. This unusual anomaly of the magnetic susceptibility is possible only in the case of a certain type of degeneracy of two electronic energy bands at a point of the Brillouin zone of the crystal, and if the chemical potential is found in the vicinity of the degeneracy energy. In particular, such degeneracy of the bands takes place in crystals with the A-15 structure (e.g., in V3Si). The results can be used to explain the strong temperature dependence of the magnetic susceptibility observed in A-15 superconducting materials in the normal state.
Force of optical radiation pressure on a spheroidal metallic nanoparticle near a plasmon resonance
Authors: Grigorchuk N. I. , Tomchuk P. M.
Published: October 2007

The problem of finding the pressure force exerted by polarized light on a spheroidal metallic nanoparticle is solved theoretically. Analytical expressions for this force averaged over the period of the incident wave are obtained which relate it to the conductivity tensor of the particle. It is shown that the conservative and dissipative components of the pressure force depend substantially on the shape of the nanoparticle and on its orientation with respect to the direction of incidence of the radiation. The behavior of the pressure force near a plasmon resonance in a spheroidal metallic nanoparticle is investigated. The dependence of the frequency shift of the resonance peak of the radiation pressure on the shape of the particle is established, and it is found to be independent of the volume of the particle.
Optical absorption spectra in thin films of M2Ag1−xCuxI3(M=K,Rb,Cs) solid solutions
Authors: Miloslavsky V. K. , Yunakova O. N. , Kovalenko E. N.
Published: October 2007

A study is made of the excitonic absorption spectra of solid solutions of the system (KI)2–(1−x)AgI–xCuI. On the basis of the dependence of the parameters of the excitonic bands on the concentration x, it is established that solid solutions of the type K2Ag1−xCuxI3 are formed in the range 0≤x≤0.2. Substitution of Ag atoms by Cu atoms in the AgI42− tetrahedra, which form chains in the orthorhombic crystal K2AgI3, promotes the formation of quasi-1D exciton bands and spectra of the persistence type, according to the Onodera–Toyozawa classification, with a splitting off of the impurity band from the exciton band. Comparison with the results of studies of the excitonic spectra in solid solutions Rb2Ag1−xCuxI3 and Cs2Ag1−xCuxI3 attests to the appearance of the Rashba effect at small x and to qualitative agreement with the Onodera–Toyozawa theory.
Energy characteristics of boron impurity in Si∕Si1−xGex heterostructures with on-center and on-edge selective doping of quantum wells
Authors: Vainberg V. V. , Gudenko Yu. N. , Poroshin V. N. , Tulupenko V. N. , Cheng N. N. , Yang Z. P. , Mashanov V. , Wang K. Y.
Published: October 2007

It is shown experimentally that when an acceptor impurity is shifted from the center to the edge of the quantum wells in Si∕Si1−xGex heterostructures, the binding energy of the ground state of the impurity decreases and the radius of localization of the carriers increases.
Anomalous resistivity due to kink modes in a thin current sheet
Authors: Moritaka Toseo , Horiuchi Ritoku , Ohtani Hiroaki
Published: October 2007

The roles of microscopic plasma instabilities on the violation of the frozen-in constraint are investigated by examining the force balance equation based on explicit electromagnetic particle simulation for a thin current sheet. Wave-particle interactions associated with lower hybrid drift instability and drift kink instability (DKI) contribute to the wavy electric force term at the periphery of the current sheet and the wavy magnetic force term at the neutral sheet, respectively. In the linear growing phase of DKI, the wavy magnetic force term balances with the electric force term due to the dc electric field at the neutral sheet. It is concluded that the growth of DKI can create anomalous resistivity and result in the violation of the frozen-in constraint as well as the diffusion of current density.
Ab initio calculations of nitrogen oxide reactions: Formation of N2O2, N2O3, N2O4, N2O5, and N4O2 from NO, NO2, NO3, and N2O
Authors: Glendening Eric D. , Halpern Arthur M.
Published: October 2007

Ab initio computational methods were used to obtain ΔrHo, ΔrGo, and ΔrSo for the reactions 2NO⇌N2O2 (I), NO+NO2⇌N2O3 (II), 2NO2⇌N2O4 (III), NO2+NO3⇌N2O5 (IV), and 2N2O⇌N4O2 (V) at 298.15K. Optimized geometries and frequencies were obtained at the CCSD(T) level for all molecules except for NO, NO2, and NO3, for which UCCSD(T) was used. In all cases the aug-cc-pVDZ (avdz) basis set was employed. The electronic energies of all species were obtained from complete basis set extrapolations (to aug-cc-pV5Z) using five different extrapolation methods. The [U]CCSD(T)/avdz geometries and frequencies of the NxOy compounds are compared with literature values, and problems associated with the values and assignments of low-frequency modes are discussed. The standard entropies are compared with values cited in the NIST/JANAF tables [NIST-JANAF Thermochemical Tables, J. Phys. Chem. Ref. Data Monograph No. 9, 4th ed. edited by M. W. Chase, Jr. (American Chemical Society and American Institute of Physics, Woodbury, NY, 1988)]. With the exception of I, in which the dimer is weakly bound, and V, for which thermodynamic data appears to be lacking, the calculated standard thermodynamic functions of reaction are in good agreement with literature values obtained both from statistical mechanical and various equilibrium methods. A multireference-configuration interaction calculation (MRCI+Q) for I provides a De value that is consistent with previous calculations. The combined uncertainties of the NIST/JANAF values for ΔrHo, ΔrGo, and ΔrSo of II, III, and IV are discussed. The potential surface for the dissociation of N2O4 was explored using multireference methods. No evidence of a barrier to dissociation was found.
Interfacial colloidal sedimentation equilibrium. II. Closure-based density functional theory
Authors: Lu Mingqing , Bevan Michael A. , Ford David M.
Published: October 2007

In Part I [R. E. Beckham and M. A. Bevan, J. Chem. Phys. 127, 164708 (2007)], results were presented for the sedimentation equilibrium of concentrated colloidal dispersions using confocal scanning laser microscopy experiments, Monte Carlo (MC) simulations, and a local density approximation perturbation theory. In this paper, we extended the modeling effort on those systems to include nonlocal density functional theory (DFT), which is capable of predicting the microstructure of the sediment at length scales comparable to the colloidal particle dimension. Specifically, we use a closure-based DFT formulation to predict interfacial colloidal sedimentation equilibrium density profiles. The colloid-colloid and colloid-surface interactions were modeled with DLVO screened electrostatic potentials using parameters taken directly from the experimental work. The DFT profiles were compared to the experimental and MC results from Part I. Good agreement was found for relatively dilute interfacial colloidal fluids, but agreement was less satisfactory as interfacial layering became more pronounced for conditions approaching the onset of interfacial crystallization. We also applied DFT in an inverse sense using the measured colloid density profile to extract the underlying colloid-surface potential; this can be thought of as a microscopic analog to the well-known procedure of using the macroscopic (coarse-grained) density profile to extract the osmotic equation of state. For the dilute interfacial fluid, the inverse DFT calculations reproduced the true colloid-surface potential to within 0.5kT at all elevations.
Relationships between the single particle barrier hopping theory and thermodynamic, disordered media, elastic, and jamming models of glassy systems
Authors: Schweizer Kenneth S.
Published: October 2007

The predictions of the ultralocal limit of the activated hopping theory of highly viscous simple fluids and colloidal suspensions [K. S. Schweizer and G. Yatsenko, J. Chem. Phys. 127, 164505 (2007), preceding paper] for the relaxation time and effective activation barrier are compared with those of diverse alternative theoretical approaches and computer simulation. A nonlinear connection between the barrier height and excess pressure as empirically suggested by simulations of polydisperse repulsive force fluids is identified. In the dense normal and weakly dynamical precursor regime, where entropic barriers of hard spheres are nonexistent or of order the thermal energy, agreement with an excess entropy ansatz is found. In the random close packing or jamming limit, the barrier hopping theory predicts an essential singularity stronger than the free volume model, which is in agreement with the simplest entropic droplet nucleation and replica field theoretic approaches. Upon further technical simplification of the theory, close connections with renormalization group and nonperturbative memory function based studies of activated transport of a Brownian particle in a disordered medium can been identified. Several analytic arguments suggest a qualitative consistency between the barrier hopping theory and solid-state elastic models based on the high frequency shear modulus and a molecular-sized apparent activation volume. Implications of the analysis for the often high degeneracy of conflicting explanations of glassy dynamics are discussed.
Modeling of rf energy sensing and harvesting using the giant thermoelectric effect in carbon nanotubes
Authors: Dragoman M. , Dragoman D. , Plana R.
Published: October 2007

The paper presents the modeling of rf energy sensing and harvesting using the giant thermoelectric effect encountered in carbon nanotubes and proposes a harvester based on this principle. The rf energy is transformed into dc voltage, conferring to the harvesting device the property of self-powering and thus the portability, which is a prerequisite of ultradense wireless nodes that form advanced wireless sensor networks and, in principle, of any portable wireless device.
Interfacial colloidal sedimentation equilibrium. I. Intensity based confocal microscopy
Authors: Beckham Richard E. , Bevan Michael A.
Published: October 2007

This paper reports confocal microscopy measurements of inhomogeneous colloidal sedimentation equilibrium profiles near planar wall surfaces for conditions when colloid dimensions are comparable to the characteristic gravitational length scale. The intensity based confocal method developed in this work enables real-space measurements of one-dimensional density profiles of Brownian colloids without identifying many single colloid centers in large imaging volumes. Measured sedimentation equilibrium profiles for single-phase interfacial fluids and for coexisting inhomogeneous fluid and solid phases are in agreement with a perturbation theory and Monte Carlo simulations within the local density approximation. Monte Carlo simulated colloid scale density profiles display some minor differences with confocal images in terms of microstructural transitions involving the onset of interfacial crystallization and the precise elevation of the fluid-solid interface. These discrepancies are attributed to polydispersity unaccounted for in the analyses, sensitivity of the perturbation theory to the effective hard sphere size, and the influence of ensemble, system size, and box shape in Monte Carlo simulations involving anisotropic∕inhomogeneous solids. Successful demonstration of intensity based confocal microscopy provides a basis for future measurements of three-dimensional colloidal interactions, dynamics, and structure near surfaces.
Phase transition in bottom-up BaTiO3 films on Si
Authors: Kato Kazumi , Tanaka Kiyotaka , Suzuki Kazuyuki , Kayukawa Shingo
Published: October 2007

The phase transition was electrically investigated in (100)-oriented BaTiO3 thin and thick films deposited on Si substrate using double alkoxide solutions. Changes of the dielectric constant as a function of temperature in the range of −200–200°C indicate that the transition from paraelectric to ferroelectric phase takes place around at 100°C instead of 130°C for single crystals. The broad peak of the dielectric constant shifted to lower temperatures and the behavior was associated with the crystallinity, orientation degree, and microstructure of the films. A highly (100)-oriented columnar BaTiO3 thin film with thickness of 280nm exhibited two transitions at 0 and 100°C from orthorhombic to tetragonal and tetragonal to cubic, respectively, while the 1μm thick BaTiO3 film with a combined structure consisted of columnar and granular grains showed a transition at 105°C.
Intercalation of fullerite C60 with N2 molecules. An investigation by x-ray powder diffraction
Authors: Galtsov N. N. , Prokhvatilov A. I. , Dolgova G. N. , Cassidy D. , Gadd G. E. , Moricca S. , Sundqvist B.
Published: October 2007

The lattice parameter a of fullerite C60 intercalated with N2 molecules is investigated in the temperature interval 6–295K by x-ray diffraction. It is found that the interstitial molecular N2 has a considerable effect on both the orientational phase transition temperature Tc and the orientational glass formation temperature Tg. Hysteresis of a(T) in the Tc and Tg regions is detected, along with an abrupt change in volume over the region defining Tc. Complete intercalation of C60 with N2 molecules results in a 0.2% increase in the lattice parameter, which persists over the whole temperature range. Evidence is also obtained that the interstitial guest molecular N2 induces a slight deformation of the cubic symmetry of the C60 host lattice.
Conductivity anomaly of a nonuniform quasi-one-dimensional electron channel over liquid helium
Authors: Kovdrya Yu Z. , Nikolaenko V. A. , Smorodin A. V.
Published: October 2007

We have investigated experimentally the conductivity of a quasi-one-dimensional electron system in a conducting channel over liquid helium in the temperature interval 0.5–1.9K. It is established that for a number of substrates anomalies are observed on the curve of the conductivity versus the potential of the confining electric field (a sharp decrease of the conductivity). Such behavior of the conductivity is apparently due to variations of the potential along the conducting channel due to different kinds of nonuniformities.
Internal photoemission at interfaces of high-κ insulators with semiconductors and metals
Authors: Afanas’ev V. V. , Stesmans A.
Published: October 2007

Internal photoemission spectroscopy provides the most straightforward way to characterize the relative energies of electron states at interfaces of insulators with metals and semiconductors by measuring the spectral onset of electron/hole photoemission from one solid into another. The article reviews the application of this technique for characterization of advanced nanometer-thin insulators prospected to be used in microelectronic devices. Fundamental aspects and technical features of the internal photoemission experiments are discussed together with basic electronic properties of a number of investigated high-permittivity insulating films and their interfaces in semiconductor heterostructures. Significant differences are found in the electronic properties of nanometer-thin amorphous insulating layers as compared to the known bulk phase characteristics. The band alignment at the interfaces of these insulators with metals is found to be highly sensitive to the surface preparation procedures. By contrast, at semiconductor/oxide interfaces the parameters of occurring interlayers affect the energy barriers only marginally at least in the case of studied oxides with close bandgap width (5.6–5.9eV). The latter finding is in favor of the models describing the band offsets at semiconductor/insulator interfaces on the basis of the bulk density of electron states. Deviation of metal/oxide interfaces from this simple behavior is explained by (unintentional) formation of a polarization layer at the interface which may contain uncompensated charges and dipoles affecting the barrier height.
Integrable boundary value problems for elliptic type Toda lattice in a disk
Authors: Gürses Metin , Habibullin Ismagil , Zheltukhin Kostyantyn
Published: October 2007

The concept of integrable boundary value problems for soliton equations on R and R+ is extended to regions enclosed by smooth curves. Classes of integrable boundary conditions in a disk for the Toda lattice and its reductions are found.
Temperature scanning small angle x-ray scattering measurements of structural relaxation in type-III vitreous silica
Authors: Brüning R. , Levelut C. , Le Parc R. , Faivre A. , Semple L. , Vallee M. , Simon J.-P. , Hazemann J.-L.
Published: October 2007

The fictive temperature of vitreous silica containing approximately 900wtppm of hydroxyl groups was monitored with small angle x-ray scattering. The measurements were carried out during annealing and while scanning the temperature, with annealing temperatures ranging between 930 and 1330K. Fitting the data to the Adam-Gibbs-Fulcher equation by using the Tool-Narayanaswamy method yields a particularly simple thermorheological behavior for type-III vitreous silica. Unlike the general case for glass kinetics, including vitreous silica with low hydroxyl content, the relaxation time constant is nearly decoupled from the fictive temperature. This high degree of decoupling of the state of the glass and the relaxation rate agrees with the results of viscosity measurements. By improving the data analysis procedure, we have significantly increased the precision of the results, and it was possible to resolve changes of the activation energy of the relaxation processes to within 0.5%. This has made sample aging effects that had previously been undetectable visible.
Nonuniform structural degradation in porous organosilicate films exposed to plasma, etching, and ashing as characterized by x-ray porosimetry
Authors: Lee Hae-Jeong , Soles Christopher L. , Lin Eric K. , Wu Wen-li , Liu Youfan
Published: October 2007

X-ray porosimetry is used to characterize the porosity, the average film density, and the density of the wall material between the pores in ultralow-k films as a function of film thickness. These measurements are performed on films that have been plasma treated as well as plasma etched and an ashed to evaluate how these integration processes affect the pore characteristics of the interlayer dielectric. The damage, a decrease of porosity and an increase in the wall density, is strongly localized to the exposed surface of the film. The plasma etching and ashing tend to induce more surface damage than the plasma alone.
Novel x-ray multispectral imaging of ultraintense laser plasmas by a single-photon charge coupled device based pinhole camera
Authors: Labate L. , Giulietti A. , Giulietti D. , Köster P. , Levato T. , Gizzi L. A. , Zamponi F. , Lübcke A. , Kämpfer T. , Uschmann I. , Förster E.
Published: October 2007

Spectrally resolved two-dimensional imaging of ultrashort laser-produced plasmas is described, obtained by means of an advanced technique. The technique has been tested with microplasmas produced by ultrashort relativistic laser pulses. The technique is based on the use of a pinhole camera equipped with a charge coupled device detector operating in the single-photon regime. The spectral resolution is about 150eV in the 4–10keV range, and images in any selected photon energy range have a spatial resolution of 5μm. The potential of the technique to study fast electron propagation in ultraintense laser interaction with multilayer targets is discussed and some preliminary results are shown.
Feedback based simultaneous correction of imaging artifacts due to geometrical and mechanical cross-talk and tip-sample stick in atomic force microscopy
Authors: Shegaonkar Ajit C. , Salapaka Srinivasa M.
Published: October 2007

This paper presents a feedback scheme that simultaneously corrects, in real time, for the imaging artifacts caused by cantilever and photosensor misalignments as well as misinterpretations in relative lateral position of the tip with respect to the sample due to the tip-sample stick in atomic force microscopy (AFM). The optical beam bounce method, typically used in AFM for imaging, is sensitive to inaccuracies of cantilever geometry and the relative misalignment of the laser source, cantilever, and the laser sensitive diode from the intended design. These inaccuracies, which contribute to the geometrical cross-talk between the normal and the lateral signals, become prominent at the atomic and subnanometer scales, and thereby impede high resolution imaging studies. The feedback scheme accounts for these artifacts and makes imaging insensitive to, in fact, practically independent of these inaccuracies. This scheme counteracts the lateral twisting dynamics of the cantilever, and as a result, it avoids the misinterpretation problem of the relative lateral position of the cantilever tip from the sample and thereby avoids the corresponding imaging artifacts that are typically prominent in contact mode friction force microscopy (FFM). The feedback scheme consists of simultaneously regulating the normal as well as the lateral cantilever deflection signal at their respective set points. This not only removes the imaging artifacts due to geometrical misalignments, mechanical cross-talk, and irregular sliding but also the corresponding compensatory control signal gives a more accurate real time measure of the lateral interaction force between the sample and the cantilever as compared to the lateral deflection signal used in FFM. Experimental results show significant improvement, and in some cases, practical elimination of the artifacts. The design and implementation of a split piezoassembly needed for the lateral actuation for the feedback scheme are also presented.
Bulk Cr tips for scanning tunneling microscopy and spin-polarized scanning tunneling microscopy
Authors: Li Bassi A. , Casari C. S. , Cattaneo D. , Donati F. , Foglio S. , Passoni M. , Bottani C. E. , Biagioni P. , Brambilla A. , Finazzi M. , Ciccacci F. , Duò L.
Published: October 2007

A simple, reliable method for the preparation of bulk Cr tips for scanning tunneling microscopy (STM) is proposed and its potentialities in performing high-quality and high-resolution STM and spin-polarized STM (SP-STM) are investigated. Cr tips show atomic resolution on ordered surfaces. Contrary to what happens with conventional W tips, rest atoms of the Si(111)-7×7 reconstruction can be routinely observed, probably due to a different electronic structure of the tip apex. SP-STM measurements of the Cr(001) surface showing magnetic contrast are reported. Our results reveal that the peculiar properties of these tips can be suited in a number of STM experimental situations.
Refractive indices of layered semiconductor ferroelectrics TlInS2, TlGaS2, and TlGaSe2 from ellipsometric measurements limited to only layer-plane surfaces
Authors: Shim YongGu , Okada Wataru , Wakita Kazuki , Mamedov Nazim
Published: October 2007

The ternary layered Tl-contained semiconductor ferroelectrics TlInS2, TlGaS2, and TlGaSe2, exhibiting an incommensurate phase and a relaxor state with temperature, were approached down to 0.76eV at room temperature by spectroscopic phase modulated ellipsometry in a region below the energy gap of each material. By using both coherent and incoherent reflection modes on only the layer-plane surfaces, the refractive indices in the parallel- and perpendicular-to-the-layers directions of the light propagation were determined. Sellmeier single-oscillator form was used to fit the model data to the experimental intensities. The discrepancy between the model and experimental data was shown to be negligible. Besides, a self-consistent picture of the obtained refraction indices was emerging after the discussion based on the available data for the studied materials. The applied experimental approach was thus found to be quite effective for layered materials, and the obtained refractive indices might be used for database with high degree of confidence.
Magnetic field enhanced thermal conductivity in heat transfer nanofluids containing Ni coated single wall carbon nanotubes
Authors: Wright Brian , Thomas Dustin , Hong Haiping , Groven Lori , Puszynski Jan , Duke Edward , Ye Xiangrong , Jin Sungho
Published: October 2007

In this paper, we report that the thermal conductivity (TC) of heat transfer nanofluids containing Ni coated single wall carbon nanotube can be enhanced by applied magnetic field. A reasonable explanation for these interesting results is that Ni coated nanotubes form aligned chains under applied magnetic field, which improves thermal conductivity via increased contacts. On longer holding in magnetic field, the nanotubes gradually move and form large clumps of nanotubes, which eventually decreases the TC. When we reduce the magnetic field strength and maintain a smaller field right after TC reaches the maximum, the TC value can be kept longer compared to without magnetic field. We attribute gradual magnetic clumping to the gradual cause of the TC decrease in the magnetic field. We also found that the time to reach the maximum peak value of TC is increased as the applied magnetic field is reduced. Scanning electron microscopy images show that the Ni coated nantubes are aligned well under the influence of a magnetic field. Transmission electron microscopy images indicate that nickel remains attached onto the nanotubes after the magnetic field exposure.
Room temperature exchange bias and spin valves based on BiFeO3∕SrRuO3∕SrTiO3∕Si (001) heterostructures
Authors: Martin Lane W. , Chu Ying-Hao , Zhan Qian , Ramesh R. , Han Shu-Jen , Wang Shan X. , Warusawithana Maitri , Schlom Darrell G.
Published: October 2007

We report the growth and characterization of exchange bias and spin valve heterostructures based on the multiferroic antiferromagnet BiFeO3 on Si (001) substrates. Using Co0.9Fe0.1 as the ferromagnet, we demonstrate heterostructures with large negative exchange bias and negligible training (or a decrease in exchange bias field as a function of repeated magnetic cycling) at room temperature. We additionally report the manufacture of spin valve structures that have been found to have current in-plane magnetoresistance of over 2.25% at room temperature.
Submegahertz linewidth at 240GHz from an injection-locked free-electron laser
Authors: Takahashi Susumu , Ramian Gerald , Sherwin Mark S. , Brunel Louis-Claude , van Tol Johan
Published: October 2007

Radiation from an ultrastable 240GHz solid state source has been injected, through an isolator, into the cavity of the University of California, Santa Barbara millimeter-wave free-electron laser (FEL). High-power FEL emission, normally distributed among many of the cavity’s longitudinal modes, is concentrated into the single mode to which the solid state source has been tuned. The linewidth of the FEL emission is 0.5MHz, consistent with the Fourier transform limit for the 2μs pulses. This demonstration of frequency-stable, ultranarrow-band FEL emission is a critical milestone on the road to FEL-based pulsed electron paramagnetic resonance spectroscopy.
Diffusion-controlled charge injection model for organic light-emitting diodes
Authors: Li Ling , Meller Gregor , Kosina Hans
Published: October 2007

We present an compact model to describe the charge injection for organic light-emitting diodes. By identifying a critical distance where the concentration of carriers in the extended states equals that of the trapped carriers, we obtain a model for the injection current, which links the drift-diffusion and the multiple-trapping theories. This model yields the injection current as a function of electric field, temperature, and barrier height between metal and organic semiconductor. Good agreement with recent experimental data is observed. The effect of the field-dependent mobility on the injection current is also discussed.