bluuebunny/crossref_metadata_2025 huggingface dataset:
Personality trait differences in boys and girls with clinical or sub‐clinical diagnoses of conduct disorder versus antisocial personality disorder
Authors: Taylor Jeanette , Iacono William G.
Published: October 2006

This study tested differences in personality traits measured by the Multidimensional Personality Questionnaire (MPQ) in a community sample of adolescents with definite or probable conduct disorder (CD) diagnoses that did not progress to a diagnosis of antisocial personality disorder (ASPD) by early adulthood (n=43), those with definite or probable ASPD that persisted into early adulthood (n=68), or controls with neither a CD nor an ASPD diagnosis (n=716) to examine whether antisocial behaviour disorders that differed in course were associated with differences in personality traits. As expected, boys and girls with ASPD were significantly different from controls on constraint, and those with ASPD were significantly lower on constraint than those with only CD. The results suggest that individual differences in certain personality traits may contribute to differences in the type of antisocial behaviour disorder that emerges and thereby to the course of antisocial behaviour.
You: The Smart Patient
Authors: Beckwith Helen
Published: October 2006

You: The Smart Patient Michael F. Roizen and Mehmet C. Oz with the Joint Commission and Joint Commission Resources, 2006, 412 pages $ 14.95 softcover
Foundations in Nursing and Health Care: Profiles and Portfolios of Evidence
Authors: Henderson Lesley
Published: October 2006

Foundations in Nursing and Health Care: Profiles and Portfolios of Evidence, Ruth Pearce, 2003, 124 pages, £14 softcover
Extensional v. contractional origin for the southern Menderes shear zone, SW Turkey: tectonic and metamorphic implications
Authors: BOZKURT ERDİN
Published: October 2006

The southern Menderes Massif in southwest Turkey consists mainly of orthogneisses and overlying Palaeozoic–Middle Paleocene schists and marbles. The contact between the two distinct rock types is almost everywhere structural, herein named the southern Menderes shear zone: a S-facing, high-angle ductile shear zone that separates metamorphic rocks of differing grade. Although there is a consensus that the shear zone was associated with top-to-the-S–SSW shearing and is of Tertiary age, its origin and nature have been highly debated over the last decade. Some claim the contact is a thrust fault, while others have argued for an extensional shear zone. Integration of field and microstructural data (the identification of different fabrics, associated kinematics and overprinting relationships) with fission-track thermochronology and the P–T paths of the rocks above and below the shear zone, supports the conclusion that the southern Menderes shear zone is an extensional shear zone and not a thrust. The data are consistent with a model that the exhumation and cooling of the southern Menderes Massif occurred after a period of extensional deformation. Pervasive top-to-the-N–NNE high-temperature–medium-pressure ductile shear structures (D2 deformation) overprint an early HP event (D1 deformation). The subsequent top-to-the-S–SSW greenschist shear band foliation (D3 deformation) developed mostly around the orthogniess–schist contact and forms the most characteristic features of the massif. The top-to-the-N–NNE structures are attributed to the main Alpine constructional deformation that developed during back-thrusting of the Lycian nappes during the latest Palaeogene collision between the Sakarya continent and the Anatolide-Tauride platform across the Neotethyan Ocean. The top-to-the-S–SSW structures are interpreted to be the result of the exhumation of the massif during the activity of the southern Menderes shear zone. The presence of these two distinct fabrics with differing kinematics suggests that the southern Menderes shear zone operated as a top-to-the-N–NNE thrust fault during early Alpine contractional deformation but was later reactivated with an opposite sense of movement (top-to-the-S–SSW) during subsequent Oligocene–Miocene extensional collapse.
Tracheoesophageal compression associated with substernal goitre. Correlation of symptoms with cross-sectional imaging findings
Authors: Mackle T , Meaney J , Timon C
Published: October 2006

Objective: The aim of this study was to compare the subjective tracheoesophageal pressure symptoms associated with substernal goitres with objective cross-sectional radiographic measurements.

Design: Patients with substernal goitre were questioned regarding tracheoesophageal compression symptoms and these data were analysed for correlation with radiographic and intra-operative findings.

Results: Twenty-six patients were included. Patients with airway symptoms including dyspnoea, stridor and coughing were more likely to have significant tracheal narrowing on pre-operative computed tomography (CT) imaging. There was also a significant correlation between the perceived severity of lump sensation in the throat and the presence of tracheal and oesophageal displacement and retrotracheal extension of the thyroid mass.

Conclusion: Pre-operative CT measurements of tracheal and oesophageal displacement, retrotracheal extension and the degree of tracheal compression correlate well with the presence and severity of tracheoesophageal pressure symptoms. None of the radiographic findings that are exclusive to substernal goitre (percentage of substernal mass, goitre size at the level of the thoracic inlet, ratio of goitre size to the vertebral body at the thoracic inlet and retrosternal isthmus size) had any correlation with clinical symptoms in this study.
Tuppiap Qeqertaa (Tobias Island): a newly discovered island off northeast Greenland
Authors: Bennike Ole , Mikkelsen Naja , Forsberg Rene , Hedenäs Lars
Published: October 2006

The small island of Tuppiap Qeqertaa, formerly known as Tobias Ø or Tobias Island, is situated 80 km off the northeast Greenland coast. The island was discovered in 1993 and is approximately 2 km long and 1.5 km wide. Most of the island is covered by an ice cap that rises to 35 m above sea level, as determined by airborne laser scanning. High-quality geodetic GPS measurements determine the position of a small cairn erected on the island to 79°20′34.48′′ N, 15°46′31.23′′ W. Minor parts of the island are ice free, with small hills of gravel. Late Holocene shells of marine bivalves have been found and were presumably brought up by ice floe push. Shell fragments of southern extralimital marine invertebrates point to the presence of pre-Holocene deposits. Three species of moss are the only land plants that have been found on the island.
Accreditation as a regulatory option for Antarctic bioprospecting
Authors: Weber Melissa
Published: October 2006

The current lack of a specific policy regime for Antarctic biological prospecting (bioprospecting) has emerged as a focus of recent discussion. Consideration has been given to the interface of the Convention on Biological Diversity (CBD), the United Nations Convention on the Law of the Sea (UNCLOS) and the Antarctic Treaty System (ATS). This paper aims to introduce the potential for industry accreditation to address existing regulatory uncertainty. The Marine Stewardship Council (MSC) accreditation for sustainable fisheries and the accreditation scheme being developed for Antarctic tour operators provide examples of industry accreditation that interplay with the Antarctic Treaty System. Accreditation may provide an avenue for industry to promote legitimate activities, demonstrate willingness to comply with existing principles and established regulations while the perception of being over-regulated is potentially reduced. Accreditation may also serve as an interim solution while more binding measures are developed. While Antarctic bioprospecting accreditation is not without its limitations, it does provide an avenue for the Antarctic Treaty Consultative Parties (ATCPs) to engage industry stakeholders, clarify existing obligations and promote a regulatory initiative in conformity with the principles of the Antarctic Treaty System.
Risk Perception and Acceptance— One Process or Two?
Authors: Sokolowska Joanna
Published: October 2006

The experiments discussed here are aimed at determining whether risk perception and risk acceptance are two distinct psychological processes. This study is motivated by the idea of a double‐criterion model of choice. In particular, in line with risk‐value (R‐V) models, in which risk is treated as a primitive, it is tested whether risk is independent of aspirations and whether preferences depend on aspirations. In two experiments, 305 university students were presented with pairs of risky projects and were asked to compare their riskiness and select one. The aspiration level, defined as the target return on the project, was set through an explicit instruction. In Experiment 1, a within‐subject design was applied, and thus aspirations were set at two different levels. In Experiment 2, with a between‐subject design, two different aspiration levels were set for each group. The results indicate that risk ordering is insensitive to changes in aspirations, but preferences are sensitive to those changes. This supports distinctness of risk perception and risk acceptance. The findings are discussed in terms of the CPT and SP/A models and the R‐V approach. It appears that double‐criterion models provide better and psychologically sounder predictions of subjects' preferences.
Investigating the Mechanisms Underlying Affective Priming Effects Using a Conditional Pronunciation Task
Authors: Pecchinenda Anna , Ganteaume Christiane , Banse Rainer
Published: October 2006

Recently, using a conditional pronunciation task, De Houwer and Randell (2004) reported evidence of affective priming effects only when pronunciation depended on the semantic category of targets. Although these findings support the notion that spreading of activation is the mechanism underlying affective priming effects, an explanation in terms of postlexical mechanism could not be ruled out. To clarify this point, we conducted two experiments in which nouns for both the to‐be‐pronounced as well as the not‐to‐be pronounced targets were used and all stimuli were affectively valenced words. In Experiment 1, the to‐be‐pronounced targets were object‐words, and the not‐to‐be‐pronounced targets were person‐words, whereas in Experiment 2, the instructions were reversed. Results of experiment 1 showed affective priming effects only when pronunciation of target words was conditional upon their semantic category. Most importantly, affective priming effects were observed for both object‐words (Experiment 1) and person‐words (Experiment 2). These results are compatible with a spreading activation account, but not with a postlexical mechanism account of affective priming effects in the pronunciation task.
Composition and mixing of individual particles in dust and nondust conditions of north China, spring 2002
Authors: Yuan Hui , Zhuang Guoshun , Rahn Kenneth A. , Zhang Xingying , Li Yongliang
Published: October 2006

Individual particles were sampled in Beijing during the unusually strong dust storm of 20 March 2002 (DS) and a nondust day (NDS) and in Duolun, Inner Mongolia (DL), on a nondust day. Fourteen elements were measured in 500 particles of each by SEM‐EDX. The main components were clay, quartz, calcite, and sulfur. The mineral aerosol compositionally resembled loess. X‐Y plots of SiO2 versus SO3 and Al2O3 revealed a central core of clay, with lines radiating outward toward quartz, calcite, salts, and alumina. The core represented externally mixed clay particles, and the lines represented internally mixed clays and other components. Externally mixed particles (mostly clays) amounted to 65% of the total in DS, 60% in DL, and 50% in NDS. Saline minerals contributed considerable amounts of S, P, and Cl, especially in DS and DL, and could have come from dried salt lakes or saline soils in northern China and southern Mongolia. The strongest correlations of the 14 elements measured were within these salts, not within the aluminosilicate elements. Most Ca existed as calcite in DS and DL, but as CaSO4 in NDS. S was very abundant in many of the particles in NDS, while a few of these were unambiguously pollution S in DS. High CuO and Al2O3 were found in Duolun, probably from nearby pollution sources. Dust storm aerosol can interact with pollution gases and pollution aerosol during transport to Beijing, although such interactions appear to require longer transport times to observe. SEM photos showed that calcite could serve as a substrate for adsorbing SO2 or sulfuric acid and ammonium sulfate and allowing them to react and produce gypsum or mixed sulfates.
Variation of spherical harmonic power as a function of harmonic order for Earth's core and crustal magnetic field and for Mars' crustal field
Authors: Harrison Christopher G. A.
Published: October 2006

The variation of power of the spherical harmonics of Earth's magnetic field as a function of degree is well known. At Earth's surface the power decreases as a function of degree until the crustal component dominates. At the core surface, the spectrum is flat apart from the dipole term, and each degree contributes about equally to the power. However, as a function of order the power tends to decrease for high harmonic orders. These represent sources at low geographic latitudes, and so a field in which high‐order power is low represents one in which low‐latitude sources are weaker than high‐latitude sources. Thus the explanation for the reduction in power for high‐order harmonics in Earth's core field is that in the core, low‐latitude sources of the nondipole field are less intense than high‐latitude sources. Earth's crustal field is represented by harmonic degrees greater than 15 and also shows the power falling off as a function of order, implying that there is an increase in the intensity of magnetic anomalies from equator to poles. This can be explained if the magnetizations have been produced by a dipole field aligned along the spin axis because such a field is twice as strong at the poles as at the equator. For the Martian field there is no central dipole source, but there are strong crustal sources that were created when Mars had a planetary dynamo and presumably an axial dipolar field. Martian harmonics show the same pattern of variation as a function of order as those on Earth. One explanation for this is that these crustal sources were magnetized with a dipolar field aligned along the present spin axis, implying that there has not been much Martian polar wander since the crust was magnetized.
Interactive mapping on 3‐D terrain models
Authors: Bernardin T. , Cowgill E. , Gold R. , Hamann B. , Kreylos O. , Schmitt A.
Published: October 2006

We present an interactive, real‐time mapping system for use with digital elevation models and remotely sensed multispectral imagery that aids geoscientists in the creation and interpretation of geologic/neotectonic maps at length scales of 10 m to 1000 km. Our system provides a terrain visualization of the surface of the Earth or other terrestrial planets by displaying a virtual terrain model generated from a digital elevation model overlain by a color texture generated from orthophotos or satellite imagery. We use a quadtree‐based, multiresolution display method to render in real time high‐resolution virtual terrain models that span large spatial regions. The system allows users to measure the orientations of geologic surfaces and record their observations by drawing lines directly on the virtual terrain model. In addition, interpretive surfaces can be generated from these drawings and displayed to facilitate understanding of the three‐dimensional geometry of geologic surfaces. The main strength of our system is the combination of real‐time rendering and interactive mapping performed directly on the virtual terrain model with the ability to navigate the scene while changing viewpoints arbitrarily during mapping. User studies and comparisons with commercially available mapping software show that our system improves mapping accuracy and efficiency and also yields observations that cannot be made with existing systems.
Solar forced Dansgaard/Oeschger events?
Authors: Muscheler R. , Beer J.
Published: October 2006

It has been suggested that the strong climatic changes during the last ice age, the so‐called Dansgaard/Oeschger (D/O) events, could have been prompted by solar activity changes. This hypothesis is based on the apparent cyclic occurrence of the D/O events and the solar influence on climate during the Holocene on similar time scales. We test this hypothesis by comparing the 10Be and δ18O records from the GRIP ice core. A superimposed epoch analysis allows us to reduce the noise in the data and to extract estimates of solar activity changes in connection to the D/O events. This comparison does not provide convincing evidence for a persistent solar influence on these strong climatic oscillations during the last ice age.
Extension in the western Ross Sea region‐links between Adare Basin and Victoria Land Basin
Authors: Davey F. J. , Cande S. C. , Stock J. M.
Published: October 2006

Spreading in the Adare Basin off north‐western Ross Sea (43–26 Ma) and extension in the Victoria Land Basin (VLB, > 36 Ma) are used to constrain the pole of rotation for the Adare Basin, providing a rifting model for the region for the past 45 Ma. The offset from Northern Basin to VLB at about 74°S coincides with the linear Polar‐3 magnetic anomaly, inferred to be caused by a major 48 ‐ 34 Ma igneous intrusion. The style of extension apparently changed at about 34 Ma, with the end of intrusion at the Polar‐3 anomaly, a change from highly asymmetric extension in Adare Basin, and the onset of major subsidence on the flanks of VLB. Ductile lower crustal and lithospheric flow is proposed as the cause of the inferred thick crust underlying southern Adare Basin, and a result of the constraining of extension to the adjacent contiguous Northern Basin.
Can freezing cause floods on Mars?
Authors: Wang Chi‐yuen , Manga Michael , Hanna Jeffrey C.
Published: October 2006

Floodwaters on Mars likely originated from aquifers confined below a cryosphere. We use an analytical solution to examine freezing‐induced pressurization as a mechanism for releasing groundwater. The results suggest that freezing of an aquifer of global extent under the optimal conditions, i.e., perfectly confined and with low compressibility and high permeability relative to the terrestrial analogs, can release enough floodwaters to carve an individual outflow channel, but not to explain the large total flood volume required to form the all of the outflow channels. It can also produce discharges comparable to those required for carving the outflow channels by repeated floods.
Permafrost carbon: Stock and decomposability of a globally significant carbon pool
Authors: Zimov S. A. , Davydov S. P. , Zimova G. M. , Davydova A. I. , Schuur E. A. G. , Dutta K. , Chapin F. S.
Published: October 2006

The magnitude of future CO2‐induced climate warming is difficult to predict because of uncertainties in the role of ecosystems and oceans as CO2 sources and sinks. Siberia has extensive areas (1 × 106 km2) of deep (up to 90 m) deposits of organic‐rich frozen loess (wind‐blown silt) that accumulated during the Pleistocene but have not been considered in most global carbon (C) inventories. Similar deposits occur less extensively in Alaska. Recent warming at high latitudes causes this permafrost (permanently frozen ground) to thaw, raising questions about the fate of C in thawing permafrost. Here we show that Siberian loess permafrost contains a large organic C pool (∼450 GT—more than half the quantity in the current atmosphere) that decomposes quickly when thawed, and could act as a positive feedback to climate warming.
Indications of increasing land surface evaporation during the second half of the 20th century
Authors: Brutsaert Wilfried
Published: October 2006

It is generally agreed that the evaporation from pans has been decreasing for the past half century over many regions of the Earth. However, the significance of this negative trend, as regards terrestrial evaporation, is still somewhat controversial, and its implications for the global hydrologic cycle remain unclear. The controversy stems from the alternative views that these evaporative changes resulted, either from global radiative dimming, or from the complementary relationship between pan and terrestrial evaporation. Actually, these factors are not mutually exclusive but act concurrently. It is shown quantitatively that, if the presently available data records are taken at face value, despite global dimming, the observed decreases in pan evaporation are generally evidence of increased terrestrial evaporation in those regions. This is consistent with independent hydrologic budget calculations for several large river basins in the USA, and likely further evidence of an accelerating hydrologic cycle in many areas.
Theatres of Difference: The Politics of ‘Redistribution’ and ‘Recognition’ in the Plays of Contemporary Black and Asian Women Playwrights in Britain
Authors: Griffin Gabriele
Published: October 2006

Since the 1990s, there has been an extended debate among feminists and left-wing thinkers concerned with notions of justice and equality about the relationship between ‘redistribution’ and ‘recognition’ in contemporary politics. In this article, I examine the ways in which the issues of redistribution of resources and recognition are articulated in plays by contemporary Black and Asian women playwrights such as Rukhsana Ahmad, Tanika Gupta, Winsome Pinnock, and Zindika. I shall suggest that their theatre work, and experience of working in the theatre, produce a dynamic and interdependent model of the relation between redistribution and recognition that ultimately suggests the need for recognition as the continuing primary concern of Black and Asian communities in Britain. This is evident in the plays’ contents, the theatrical forms employed by Black and Asian women playwrights (often naturalistic and issue-based), and the funding and theatre policies with which they engage. These, as I shall argue, produce tensions between the collective identities which they hail, for instance, through the appellation ‘Black playwright’, and the individual identities the playwrights seek to assert, requiring negotiations between the empowering as well as constraining demands of collective identities and the post-‘cultural diversity’ aspirations of long-term theatre politics.
Living a Body Myth, Performing a Body Reality: Reclaiming the Corporeality and Sexuality of the Indian Female Dancer
Authors: Mitra Royona
Published: October 2006

This paper investigates the dilemma that has been projected upon Indian female dancers’ bodies by contemporary Indian audiences when female desire occupies the centrality of a performance and projects the female body as sexual, articulate and independent of the discipline and propriety of classicism. Locating this dilemma in the nationalist construction of Indian womanhood and femininity as ‘chaste’, this paper adopts Victor Turner's notions of liminal and liminoid phenomenon and Brechtian defamiliarization technique as a feminist strategy to construct a framework within which the contemporary Indian dancer can reclaim her sexuality in performance. To investigate the complex nationalist trope of chaste Indian womanhood, and to analyse the subversion of this trope by placing agency on the female body as sexual, I locate my argument in the discussion of The Silk Route: Memory of a Journey by Kinaetma Theatre, UK, which was performed in Kolkata in August 2004.
Qualification of a near backscattering imaging system on the National Ignition Facility
Authors: Mackinnon A. J. , Niemann C. , Piston K. , Holtmeier G. , McCarville T. , Jones G. , Reinbachs I. , Costa R. , Celeste J. , Griffith R. , Kirkwood R. K. , MacGowan B. J. , Glenzer S. H.
Published: October 2006

A near backscattering imaging diagnostic system has been implemented, qualified, and fielded on the first quad of beams on the National Ignition Facility [E. M. Campbell and W. J. Hogan, Plasma Phys. Controlled Fusion 41, B39 (1999)]. This diagnostic image diffusing scatter plates, placed around the final focus lenses on the NIF target chamber, to quantitatively measure the fraction of light backscattered outside of the incident cone of the focusing optics. The imaging system consists of a wide-angle lens coupled to a gated charged coupled device camera, providing 3mm resolution over a 2m field of view. To account for changes of the system throughput due to exposure to target debris the system was routinely calibrated in situ at 532 and 355nm using a dedicated pulsed laser source. The diagnostic and calibration methods will be described together with recent results from the NIF early light shots.
Limiting laws of linear eigenvalue statistics for Hermitian matrix models
Authors: Pastur L.
Published: October 2006

We study the variance and the Laplace transform of the probability law of linear eigenvalue statistics of unitary invariant Matrix Models of n×n Hermitian matrices as n→∞. Assuming that the test function of statistics is smooth enough and using the asymptotic formulas by Deift et al. [ Commun. Pure Appl. Math.52, 1325–1425 (1999)] for orthogonal polynomials with varying weights, we show first that if the support of the Density of States of the model consists of q≥2 intervals, then in the global regime the variance of statistics is a quasiperiodic function of n as n→∞ generically in the potential, determining the model. We show next that the exponent of the Laplace transform of the probability law is not, in general, 1∕2× variance, as it should be if the Central Limit Theorem would be valid, and we find the asymptotic form of the Laplace transform of the probability law in certain cases.
Uniformity assessment of key characteristics of quantum-dot infrared detectors: A prerequisite for focal plane arrays
Authors: Pal D. , Towe E.
Published: October 2006

We have studied some key characteristics of individual InAs∕GaAs quantum-dot infrared photodetectors in a linear array to assess their suitability for imaging applications. The dark current-voltage characteristics of the devices in the array are almost identical. Furthermore, the low-temperature (78K) photoresponse spectra are nearly identical for all devices. The average peak responsivity was about 1.03A∕W, while the average peak detectivity was about 2.16×109cmHz1∕2∕W. The standard deviations of these two metrics and those of other important parameters were relatively small. Uniformity of individual device characteristics over large arrays is an important prerequisite for high-quality imaging arrays.
N
log
N
method for hydrodynamic interactions of confined polymer systems: Brownian dynamics
Authors: Hernández-Ortiz Juan P. , de Pablo Juan J. , Graham Michael D.
Published: October 2006

A Brownian dynamics simulation technique is presented where a Fourier-based NlogN approach is used to calculate hydrodynamic interactions in confined flowing polymer systems between two parallel walls. A self-consistent coarse-grained Langevin description of the polymer dynamics is adopted in which the polymer beads are treated as point forces. Hydrodynamic interactions are therefore included in the diffusion tensor through a Green’s function formalism. The calculation of Green’s function is based on a generalization of a method developed for sedimenting particles by Mucha et al. [J. Fluid Mech. 501, 71 (2004)]. A Fourier series representation of the Stokeslet that satisfies no-slip boundary conditions at the walls is adopted; this representation is arranged in such a way that the total O(N2) contribution of bead-bead interactions is calculated in an O(NlogN) algorithm. Brownian terms are calculated using the Chebyshev polynomial approximation proposed by Fixman [Macromolecules 19, 1195 (1986); 19, 1204 (1986)] for the square root of the diffusion tensor. The proposed Brownian dynamics simulation methodology scales as O(N1.25logN). Results for infinitely dilute systems of dumbbells are presented to verify past predictions and to examine the performance and numerical consistency of the proposed method.
A novel gravity-induced flow transition in two-phase fluids
Authors: d’Avila M. A. , Shapley N. C. , Walton J. H. , Phillips R. J. , Powell R. L. , Dungan S. R.
Published: October 2006

Experimental results are reported that show a gravity-induced flow transition in well-mixed suspensions and emulsions, even when the buoyancy-driven velocity of isolated drops or particles is several orders of magnitude smaller than the imposed velocity. The experiments were conducted with emulsions of isooctane in water and suspensions of polymethyl-methacrylate particles in water. Both the drop and particle diameters were approximately 3–5μm, and concentrations of the dispersed phases ranged from dilute (2%) to concentrated (40%). The two-phase fluids were confined to a horizontal, concentric-cylinder apparatus in which the outer cylinder was rotated, and the velocity profiles were measured by nuclear magnetic resonance imaging. The results show that the flow transition is relatively insensitive to the volume fraction of the dispersed phase. The flow transition occurs because, although the buoyancy-driven velocity is relatively small on the length scale of the particle or drop dimension, the flow itself induces a slight variation in the suspension concentration and, hence, density. Although only on the order of 10−4g∕cm3, this density difference spans a macroscopic length scale, making the buoyancy effect competitive with the imposed flow. These arguments yield a dimensionless parameter that predicts very closely the nonequilibrium phase diagram generated by the experiments.
Polarization beam splitter based on a two-dimensional photonic crystal of pillar type
Authors: Ao Xianyu , Liu Liu , Wosinski Lech , He Sailing
Published: October 2006

Negatively and positively refractive behaviors are achieved in a two-dimensional photonic crystal of pillar type for TE and TM polarizations, respectively, at the same frequency. The photonic crystal is formed by a triangular lattice of silicon pillars of finite height on a silicon substrate. A polarization beam splitter based on such a photonic-crystal slab is demonstrated. Measurements at near infrared wavelengths indicate that two beams of different polarizations can be split with an extinction ratio of over 10dB in a wide wavelength range.
Extracting electron transfer coupling elements from constrained density functional theory
Authors: Wu Qin , Van Voorhis Troy
Published: October 2006

Constrained density functional theory (DFT) is a useful tool for studying electron transfer (ET) reactions. It can straightforwardly construct the charge-localized diabatic states and give a direct measure of the inner-sphere reorganization energy. In this work, a method is presented for calculating the electronic coupling matrix element (Hab) based on constrained DFT. This method completely avoids the use of ground-state DFT energies because they are known to irrationally predict fractional electron transfer in many cases. Instead it makes use of the constrained DFT energies and the Kohn-Sham wave functions for the diabatic states in a careful way. Test calculations on the Zn2+ and the benzene-Cl atom systems show that the new prescription yields reasonable agreement with the standard generalized Mulliken-Hush method. We then proceed to produce the diabatic and adiabatic potential energy curves along the reaction pathway for intervalence ET in the tetrathiafulvalene-diquinone (Q-TTF-Q) anion. While the unconstrained DFT curve has no reaction barrier and gives Hab≈17kcal∕mol, which qualitatively disagrees with experimental results, the Hab calculated from constrained DFT is about 3kcal∕mol and the generated ground state has a barrier height of 1.70kcal∕mol, successfully predicting (Q-TTF-Q)− to be a class II mixed-valence compound.
Chemical vapor deposition growth of carbon nanotubes on Si substrates using Fe catalyst: What happens at the nanotube∕Fe∕Si interface
Authors: Chakraborty Amit K. , Jacobs J. , Anderson C. , Roberts C. J. , Hunt Michael R. C.
Published: October 2006

Direct growth of carbon nanotubes (CNTs) on silicon is of great importance for their potential exploitation in the semiconductor industry. In this article we investigate the chemical vapor deposition growth of CNTs on Si substrates from ethylene precursor using an iron catalyst. We observe that CNTs are produced only at temperatures between 830 and 980°C, and within this narrow temperature window CNT yield initially increases with temperature to reach a maximum around 900°C and then declines. While the requirement of a minimum temperature to initiate CNT growth can be understood by considering the minimum energy necessary to activate the catalyst particles, characterization of the as-grown CNTs by atomic force microscopy and x-ray photoelectron spectroscopy reveals that a loss of catalyst is responsible for the observed decline in CNT yield above 900°C. However, unlike some previous reports suggesting surface silicide formation as the mechanism for catalyst loss, we find that either subsurface diffusion or evaporation is the mechanism for the loss of catalyst material in the current study.
Power-dependent switching of microwave signals in a ferrite-film nonlinear directional coupler
Authors: Ustinov Alexey B. , Kalinikos Boris A.
Published: October 2006

The authors report the realization of a microwave nonlinear directional coupler based on a ferrite film. It is a passive device for direct signal processing at microwave frequencies. The power-dependent switching of microwave signals is demonstrated. The switching is achieved through a differential nonlinear phase shift of the operating spin waves propagating in the ferrite film.
Synthesis and memory properties of a conjugated copolymer of fluorene and benzoate with chelated europium complex
Authors: Song Y. , Tan Y. P. , Teo E. Y. H. , Zhu Chunxiang , Chan D. S. H. , Ling Q. D. , Neoh K. G. , Kang E. T.
Published: October 2006

A conjugated copolymer of diethylhexylfluorene and europium complex-chelated benzoate (PF8Eu) was synthesized. The device based on an Al/PF8Eu/indium-tin-oxide sandwich structure exhibited nonvolatile, write-once read-many-times (WORM) memory behavior. The fluorene moiety served as the backbone and electron donor, while the europium complex served as the electron acceptor. The as-fabricated device was in its low conductivity state. After applying a voltage of ∼3V, the device underwent a transition to the high conductivity state, which could not be erased by a reverse bias. In the initial low conductivity state, the device showed a charge injection controlled current. At the high conductivity state, the current-voltage characteristics were dominated by a space-charge-limited current. The device had a switching time of ∼1μs and an on/off current ratio as high as 106. No degradation in device performance was observed after 107 read cycles at a read voltage of 1V under ambient conditions. The device also exhibited good stability under a constant 1V stress. Thus, the device based on PF8Eu is potentially useful as a WORM memory.
Dynamics of a two-dimensional upflowing mixing layer seeded with bubbles: Bubble dispersion and effect of two-way coupling
Authors: Climent E. , Magnaudet J.
Published: October 2006

The evolution and structure of a spatially evolving two-dimensional mixing layer seeded with small bubbles are numerically investigated. The one-way coupling approach is first employed to show that characteristics of bubble dispersion are dominated by the possibility for sufficiently small bubbles to be captured in the core of the vortices. A stability analysis of the ordinary differential equation system governing bubble trajectories reveals that this entrapment process is governed by the presence of stable fixed points advected by the mean flow. Two-way coupling simulations are then carried out to study how the global features of a two-dimensional flow are affected by bubble-induced disturbances. The local interaction mechanism between the two phases is first analyzed using detailed simulations of a single bubbly vortex. The stability of the corresponding fixed point is found to be altered by the collective motion of bubbles. For trapped bubbles, the interphase momentum transfer yields periodic sequences of entrapment, local reduction of velocity gradients, and eventually escape of bubbles. Similar mechanisms are found to take place in the spatially evolving mixing layer. The presence of bubbles is also found to enhance the destabilization of the inlet velocity profile and to shorten the time required for the rollup phenomenon to occur. The most spectacular effects of small bubbles on the large-scale flow are a global tilting of the mixing layer centerline towards the low-velocity side and a strong increase of its spreading rate. In contrast, no significant modification of the flow is observed when the bubbles are not captured in the large-scale vortices, which occurs when the bubble characteristics are such that the drift parameter defined in the text exceeds a critical value. These two contrasted behaviors agree with available experimental results.
Coupled diabatic potential energy surfaces for studying the nonadiabatic dynamics at conical intersections in angular resolved photodetachment simulations of OHF−→OHF+e−
Authors: Gómez-Carrasco Susana , Aguado Alfredo , Paniagua Miguel , Roncero Octavio
Published: October 2006

An energy-based method is proposed for the diabatization of the OH(Π2)+F(P2)→O(P3)+HF(Σ+1) reaction. It is demonstrated that the diabatic representation obtained is regularized, i.e., the residual derivative couplings do not present singularities at the conical intersections appearing along the reaction path. This method only requires the knowledge of the 1,2A″3 and 1A′3 eigenvalues and does not require any adjustable parameter. Thus, many convergence problems arising in other derivative-based diabatization methods are avoided, and the description of the configuration space along the reaction path is enormously simplified. Three-dimensional coupled diabatic energy surfaces are obtained by an interpolation procedure using ≈4000 accurate ab initio points. The angular resolved photodetachment cross sections are obtained in the diabatic and adiabatic representations using a wave packet method. An excellent agreement is obtained with recent experimental data [D. M. Neumark, Phys. Chem. Chem. Phys. 7, 433 (2005)] for high electron kinetic energies where only the triplet electronic states contribute.
Hexagonal pyramid shaped light-emitting diodes based on ZnO and GaN direct wafer bonding
Authors: Murai Akihiko , Thompson Daniel B. , Masui Hisashi , Fellows Natalie , Mishra Umesh K. , Nakamura Shuji , DenBaars Steven P.
Published: October 2006

The authors report on hexagonal pyramid shaped light-emitting diode (LED) based on ZnO and GaN wafer bonding. After direct wafer bonding of an n-type ZnO substrate to a III-nitride LED wafer, O-plane ZnO was selectively etched to form an electrode having a truncated hexagonal pyramid shape. This wafer bonded LED chip was evaluated with optical output power as a function of forward current and was 2.2 times higher than a conventional-type LED chip having thin Ni (5nm)∕Au (10nm) p-type electrode at forward current condition of 20mA.
Ferroelectric nanotubes fabricated using nanowires as positive templates
Authors: Alexe M. , Hesse D. , Schmidt V. , Senz S. , Fan H. J. , Zacharias M. , Gösele U.
Published: October 2006

The authors report on fabrication and electrical characterization of ferroelectric nanotubes and metal-ferroelectric-metal composite nanotubes using silicon and ZnO nanowires as positive templates. Nanotubes of high aspect ratio with a minimum inner diameter of about 100nm and a length ranging from 0.5μm to a few microns have been obtained by magnetron sputtering and/or pulsed laser deposition. Metal-ferroelectric one-dimensional structures were characterized by piezoelectric scanning probe microscopy, showing piezoelectric hysteresis loops and ferroelectric switching. The presented fabrication approach can be used to fabricate three-dimensional capacitors for ferroelectric nonvolatile memories as well as nanosize piezoelectric scanners and actuators.
Magnetoresistivity modulated response in bichromatic microwave irradiated two dimensional electron systems
Authors: Iñarrea J. , Platero G.
Published: October 2006

The authors analyze the effect of bichromatic microwave irradiation on the magnetoresistivity of a two dimensional electron system. The authors follow the model of microwave driven Larmor orbits in a regime where two different microwave lights with different frequencies are illuminating the sample (w1 and w2). The authors’ calculated results demonstrate that now the electronic orbit centers are driven by the superposition of two harmonic oscillatory movements with the frequencies of the microwave sources. As a result the magnetoresistivity response presents modulated pulses in the amplitude with a frequency of (w1−w2)∕2, whereas the main response oscillates with (w1+w2)∕2.
One-dimensional tunable photonic crystals with spin crossover material for the terahertz range
Authors: Mounaix P. , Freysz E. , Degert J. , Daro N. , Létard J.-F. , Kužel P. , Vigneras V. , Oyenhart L.
Published: October 2006

The authors use a spin crossover material as a defect inserted into a periodic structure of alternating layers of glass and air. A single defect mode of this Bragg filter designed for the submillimeter wavelength can be tuned over 15GHz by inducing the spin transition of the defect. This shows potential applications of spin crossover materials at terahertz frequencies.
Design of a highly magnified directional acoustic source based on the resonant cavity of two-dimensional phononic crystals
Authors: Wu Tsung-Tsong , Hsu Chung-Hao , Sun Jia-Hong
Published: October 2006

The authors report a design of a highly magnified directional acoustic source based on the planar resonant cavity of two-dimensional phononic crystals. The authors demonstrate that the order of the resonant mode and the reflective ratio of the double phononic crystal slab are the key factors to the magnified ratio of the directional acoustic amplifier. With properly designed mode and cavity width of the asymmetric phononic structure, the optimal magnified amplitude can be achieved by more than 86.5 times in comparison with the amplitude of the original line source freely radiating in water.
Contactless electroreflectance of GaN0.025As0.975−xSbx∕GaAs quantum wells with high Sb content (0.27⩽x⩽0.33): The determination of band gap discontinuity
Authors: Kudrawiec R. , Gupta J. A. , Motyka M. , Gladysiewicz M. , Misiewicz J. , Wu X.
Published: October 2006

Ga N 0.025 As 0.975 − x Sb x ∕ Ga As quantum wells (QWs) with x=0.27 and x=0.33 were investigated by contactless electroreflectance (CER) spectroscopy. CER features related to optical transitions between the ground and excited states were clearly observed, indicating that these QWs have type-I structures. By matching the QW transition energies with those obtained from theoretical calculations performed within the electron effective mass approximation the conduction band offset in these QWs is found to be close to 40%. The resulting conduction band discontinuities were found to be ∼200 and ∼150meV for the QWs with x=0.27 and x=0.33, respectively.
Intrinsic transport and contact resistance effect in C60 field-effect transistors
Authors: Matsuoka Yukitaka , Uno Koichi , Takahashi Nobuya , Maeda Akira , Inami Nobuhito , Shikoh Eiji , Yamamoto Yoshiyuki , Hori Hidenobu , Fujiwara Akihiko
Published: October 2006

The autors report size dependence of characteristics of C60 field-effect transistors (FETs). The transport properties of the channel and the contact resistance between the channel and electrodes are extracted from size dependence. Contact resistances are comparable to those of channel resistances, and the gate voltage dependence of contact resistance is greater than that of channel resistance even at linear region. Results show that the Schottky barriers between the channel and the electrodes still affect device characteristics in the on state of C60 FETs.
Analysis of transient phenomena of C60 field effect transistors
Authors: Miyadera Tetsuhiko , Nakayama Manabu , Saiki Koichiro
Published: October 2006

Transient current excited by application of step gate voltages was investigated for C60 field effect transistors (FETs). The measurements were continued during film growth and the decay curves were obtained as a function of C60 film thickness. The decay curve contains two different relaxation times. The fast decay could be explained in terms of channel resistance and gate insulator capacitance, while the slower decay relates with trapping processes of carriers. The slower decay observed for the larger mobility film implies that mobility is not an absolute figure for evaluating the performance of organic FETs.
Olive Oil Mill Wastewater Treatment by the Electro-Fenton Process
Authors: Bellakhal Nizar , Oturan Mehmet A. , Oturan Nihal , Dachraoui Mohamed
Published: October 2006

Environmental Context. The combination of the Fenton’s reagent with electrochemistry (the electro-Fenton process) represents an efficient method for wastewater treatment. This study describes the use of this process to clean olive oil mill wastewater, which is a real environmental problem in Mediterranean countries. Contrary to the conventional methods which reduce the pollution by removing the pollutants from the wastewater, the electro-Fenton process is shown to fully destroy (mineralize) olive oil mill wastes in water without previous extraction and without addition of chemical reagents.
Abstract. Treatment of olive oil mill wastewater is one of the most important environmental problems for Mediterranean countries. This wastewater contains many organic compounds like polyphenols, which are very difficult to treat by classical techniques. An advanced electrochemical oxidation process, the electro-Fenton process, has been used as a way of removing chemical oxygen demand and colour intensity from olive oil mill wastewater. Vanillic acid, which has been selected as a model compound, and olive oil mill wastewater have been completely mineralized by the electro-Fenton process with a carbon felt cathode, using Fe2+ ions as the catalyst.