bluuebunny/crossref_metadata_2025 huggingface dataset:
Bipolare Störungen als Komorbidität im Kindes- und Jugendalter – unterdiagnostiziert oder überinterpretiert?
Authors: Rothermel Boris , Poustka Luise , Banaschewski Tobias , Becker Katja
Published: March 2010

Einleitung: Die Angaben zur Prävalenz der komorbiden bipolaren affektiven Störung bei Kinder und Jugendlichen mit Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS) zwischen den USA und Deutschland unterscheiden sich deutlich. Methoden: Anhand der Kasuistik eines 14-jährigen Jungen mit Hyperkinetischer Störung des Sozialverhaltens und Hypomanie werden unterschiedliche Bewertungsmöglichkeiten der Symptomatik diskutiert sowie Diagnose und Therapie des Patienten dargestellt. Schlussfolgerungen: Weitere Untersuchungen bei Kindern und Jugendlichen mit ADHS und impulsiv-aggressiven Verhaltensweisen sind notwendig. In der Praxis sollte eine genaue Differenzierung der Symptome bezüglich einer komorbiden bipolaren Störung erfolgen.
Evidenzbasierte Gruppentherapie bei schizophrenen Psychosen
Authors: Schaub Annette
Published: March 2010

Psychotherapie als wesentliche Ergänzung der Psychopharmakotherapie spielt in der Behandlung schizophren erkrankter Patienten eine zentrale Rolle, da Defizite in der Krankheits- und Symptombewältigung (z. B. Behandlungs-Non-Adherence) sowie im sozialen Bereich auftreten. Familieninterventionen oder kognitiv-verhaltenstherapeutische Gruppen haben in der Kombination mit Pharmakotherapie in den letzten 30 Jahren an Bedeutung gewonnen und ihre Wirksamkeit konnte in kontrolliert randomisierten Studien belegt werden. Die Effizienz im Hinblick auf Training sozialer Kompetenzen, kognitive Rehabilitation und Psychoedukation sind derzeit weniger eindeutig. Therapieziele beziehen sich auf die Verbesserung des psychosozialen Funktionsniveaus und die Rückfallprophylaxe. Es ist derzeit nicht eindeutig geklärt, ob die Einzeltherapie der Gruppentherapie überlegen ist oder vielmehr beide Ansätze gleichwertig sind.
Compliance-Aufbau im Fokus der Schizophreniebehandlung
Authors: Vauth Roland , Stieglitz Rolf-Dieter
Published: March 2010

Mangelnde Pharmakotherapie-Compliance ist nach wie vor und trotz Einführung der atypischen Antipsychotika mit einem wesentlich günstigeren Wirkungs-/Nebenwirkungsprofil als das der typischen Antipsychotika eines der zentralsten Probleme der gegenwärtigen Versorgung schizophrener Störungen. Die Lücke zwischen Effektivität und Nutzen in der Behandlung der Schizophrenie erklärt sich vor allem hieraus. Die Folgen von Mal-Compliance für den Erkrankungsverlauf sind gravierend. Ausgehend von Daten zu Prävalenz von Mal-Compliance werden wichtige Befunde referiert zu Determinanten und theoretischen Vorstellungen, die Ausgangspunkt für nachhaltigere therapeutische Interventionen werden können. Die wichtigen Interventionstypen werden in ihrer differenziellen Wirksamkeit dargestellt.
Was passiert nach der stationären Stabilisierung mit komplex traumatisierten PTB-Patientinnen?
Authors: Rosner Rita , Henkel Christine , Ginkel Katharina , Mestel Robert
Published: March 2010

Bei Patienten mit Posttraumatischen Belastungsstörungen (PTB) und zusätzlicher komplexer Thematik erfolgt in Deutschland im stationären Setting überwiegend eine Stabilisierung. Angenommen wird dabei, dass die erfolgreich Stabilisierten in einer ambulanten Folgetherapie mit einem traumakonfrontativen Verfahren behandelt werden. Die hier vorliegende Arbeit hat zwei Ziele: Erstens soll eine quantitative Literaturübersicht zum Thema Stabilisierung und Konfrontation bei komplex Traumatisierten gegeben werden. Hier zeigte sich, dass Stabilisierung überwiegend kleine bis mittlere Effekte erzielt und dass kognitiv-verhaltenstherapeutische Interventionen insgesamt erfolgreicher erscheinen. Zweitens soll die Inanspruchnahme von Folgebehandlungen nach stationärer Stabilisierung erfasst werden. Dazu wurden 147 sexuell traumatisierte Frauen, die eine stationäre, vorwiegend stabilisierende integrative Behandlung erhielten, nachuntersucht. Während sich die allgemeine psychische Belastung am Ende des stationären Aufenthalts stark verbesserte, zeigten sich nur kleine bis mittlere Effekte im Bereich der posttraumatischen Symptomatik. Nur ein geringer Teil der Stichprobe erhielt eine Traumakonfrontation in den vier Jahren nach der stationären Behandlung. Daraus und aus der Literaturübersicht kann abgeleitet werden, dass das stationäre Setting für Traumabearbeitung genutzt werden sollte.
«Mein Kittauge hat mein Leben verpfuscht!»
Authors: Grocholewski Anja , Heinrichs Nina
Published: March 2010

Beschrieben wird ein 59-jähriger Mann, der seine angeborene, als psychisch belastend erlebte Ptosis (Augenlidschwäche) im Alter von 45 Jahren chirurgisch korrigieren ließ. Nach erfolgreicher Korrektur entwickelte der Patient eine ausgeprägte körperdysmorphe Symptomatik (KDS). Der Betroffene wurde testpsychologisch untersucht und es fand eine vertiefte Exploration statt. Klinisch relevante depressive Symptome konnten unter antidepressiver Medikation mit Mirtazapin nicht festgestellt werden, berichtet wurde allerdings trotz psychopharmakologischer Behandlung eine überdurchschnittlich hohe psychopathologische Belastung. Der globale Selbstwert war durchschnittlich stark ausgeprägt. Weitere vom Aussehen unabhängige soziale Ängste lagen nicht vor. Auffällig war die Wichtigkeit, die der Patient dem äußeren Erscheinungsbild zuschreibt sowie das Ausmaß, zu dem er seinen Selbstwert über sein physisches Erscheinungsbild definiert. Die Kasuistik deckt sich mit einem integrativen Störungsmodell, welches weniger das Vorhandensein eines tatsächlichen Makels, sondern eher psychische Faktoren als Hauptursache der Entwicklung und Aufrechterhaltung einer körperdysmorphen Störung postuliert.
Prevalence of Suicidal Ideation in Sri Lanka
Authors: Samaraweera Sudath , Sumathipala Athula , Siribaddana Sisira , Sivayogan S. , Bhugra Dinesh
Published: March 2010

Background: Suicidal ideation can often lead to suicide attempts and completed suicide. Studies have shown that Sri Lanka has one of the highest rates of suicide in the world but so far no studies have looked at prevalence of suicidal ideation in a general population in Sri Lanka. Aims: We wanted to determine the prevalence of suicidal ideation by randomly selecting six Divisional Secretariats (Dss) out of 17 in one district. This district is known to have higher than national average rates of suicide. Methods: 808 participants were interviewed using Sinhala versions of GHQ-30 and Beck’s Scale for Suicidal Ideation. Of these, 387 (48%) were males, and 421 (52%) were female. Results: On Beck’s Scale for Suicidal Ideation, 29 individuals (4%) had active suicidal ideation and 23 (3%) had passive suicidal ideation. The active suicidal ideators were young, physically ill and had higher levels of helplessness and hopelessness. Conclusions: The prevalence of suicidal ideation in Sri Lanka is lower than reported from the West and yet suicide rates are higher. Further work must explore cultural and religious factors.
News, Announcements, and IASP
Authors: Munson Juliane
Published: March 2010

The 13th European Symposium on Suicide and Suicidal Behaviour (ESSSB), entitled “Integrating Knowledge for an Interdisciplinary Approach to Suicidology and Suicide Prevention,” is taking place September 1–4, 2010, in Rome, Italy. The 13th ESSSB aims at investigating possible modalities and paths of communication, favoring aggregation and interplay at a more complex level of structurization of suicidology, with the ulimative scope of harmonizing its articulate development. This symposium is organized by the Universita degli Studi del Molise and is held under auspices of the International Association for Suicide Prevention (IASP).
Modeling of a mixed‐load fluvio‐deltaic system
Authors: Geleynse N. , Storms J. E. A. , Stive M. J. F. , Jagers H. R. A. , Walstra D. J. R.
Published: March 2010

Present‐day observations and classical classification schemes of alluvial deltas address feeder channel dynamics and multiple sediment fractions. However, high‐resolution physics‐based mathematical models have not been applied to address formation of both fluvio‐deltaic links (channels) and nodes (diffluences and confluences), and their stratigraphy. Here, we present a simulated delta system under riverine forcing that shows striking similarity to its counterparts recognized in field and laboratory studies. These findings include distinct shifts in river planimetrical mode and altimetry, deltaic mouth bar and distributary formation, lateral fining in migrating‐meander bend axes and fining‐upward patterns in passive delta‐plain distributaries.
Modulation of ionospheric conductance and electric field associated with pulsating aurora
Authors: Hosokawa K. , Ogawa Y. , Kadokura A. , Miyaoka H. , Sato N.
Published: March 2010

We present, for the first time, a quasiperiodic modulation of ionospheric parameters, associated with the occurrence of pulsating auroras, such as electron density, conductance, and electric field. In March 2008, simultaneous campaign‐based measurements of pulsating auroras were conducted over Tromsø (69.60°N, 19.20°E), Norway, using an all‐sky TV camera (ATV) and the European Incoherent Scatter (EISCAT) UHF system. During an interval within this campaign period, pulsating auroras, with periods of 8–17 s, were observed by the ATV in the morning local time sector (∼0500 MLT). In this interval, quasiperiodic oscillations were identified in the raw electron density obtained by EISCAT. The electron density at lower altitudes in the E region (95–115 km) was enhanced by a factor of 3–4 immediately after the optical pulsation became “on.” The height‐integrated Hall conductance was also elevated, by a factor of 1.5–2, almost in harmony with the electron density variation. The response of the electron density and Hall conductance to the appearance of the pulsating aurora was almost immediate. However, both did not decrease to the background level promptly after optical pulsation ceased. This was primarily because it took a few seconds for the electron density to decrease through recombination with ambient ions at these altitudes. Interestingly, electric field measurements performed by the remote antenna at Kiruna showed that redirection of the electric field occurred when the pulsating aurora was “on.” We propose a model in which the enhancement of Hall conductance within patches of the pulsating aurora caused charge accumulation at the edges of the patches, and the electric field was then modified by the resulting polarization electric field. An estimation of the electric field modulation with this model well reproduced the actual electric field observations carried out by EISCAT, which confirmed the validity of the model. These results imply that the ionization caused by high‐energy electron precipitation associated with a pulsating aurora has a significant effect on the ionospheric conductivity and current system. This modification of the ionosphere may facilitate characterization of the morphological features of pulsating auroras. In particular, modification of the electric field would affect the spatial structure of pulsating aurora patches, such as their motion and shapes.
Roles of atmospheric and land surface data in dynamic regional downscaling
Authors: Ray Deepak K. , Pielke Roger A. , Nair Udaysankar S. , Niyogi Dev
Published: March 2010

In studies dealing with the impact of land use changes on atmospheric processes, a key methodological step is the validation of simulated current conditions. However, regions lacking detailed atmospheric and land use data provide limited information with which to accurately generate control simulations. In this situation, the difference between baseline control simulations and different land use change simulations can be quite different owing to the quality of the atmospheric and land use data sets. Using multiple simulations at the Monteverde cloud forest region of Costa Rica as an example, we show that when a regional climate model is used to study the effect of land use change, it can produce distinctly different results at regional scales, depending on the amount of data available to run the climate simulations. We show that for the specific case of land use change impact studies, the simulation results are very sensitive to the prescribed atmospheric information (e.g., lateral boundary conditions) compared to the land use (surface boundary) information.
Influence of climate shifts on decadal variations of surface solar radiation in Alaska
Authors: Chiacchio Marc , Ewen Tracy , Wild Martin , Arabini Elena
Published: March 2010

From past studies it has been known that the Pacific Decadal Oscillation (PDO) shifted toward a positive mode in 1976 and a new climate regime occurred that produced a warming of the mean annual and seasonal temperatures and associated increases in cloud cover and precipitation in the North Pacific including Alaska. In this study, this climate shift is examined with regard to the variations in surface solar radiation before and after 1976 during the period 1961–2005. The results show greatest changes occurring in the southeast region in winter with a significant rise of 1.67% yr−1 during 1961–1975 before the shift and a nonsignificant decline of −1.07% yr−1 during 1977–1991 after the shift. In addition to the variations in solar radiation that occurred after 1976, the PDO and the solar radiation time series show common changes around 1989 and 1998. Thus, these two variables are compared to assess the strength of their relationship. The results show a good to moderate correlation with a maximum found in winter in Big Delta (interior region). The Pacific North American (PNA) circulation pattern is also strongly correlated with the solar radiation, with a maximum in winter in Anchorage (south‐central region). In addition, a close relationship is found between cloud cover and solar radiation, particularly in the south‐central and southwest regions. These results suggest that circulation patterns and associated cloud cover changes may play a large role, especially during wintertime, in the variations in the surface solar radiation in these regions of Alaska.
Estimated carbon residence times in three forest ecosystems of eastern China: Applications of probabilistic inversion
Authors: Zhang Li , Luo Yiqi , Yu Guirui , Zhang Leiming
Published: March 2010

Carbon residence time is one critical parameter for predicting future land carbon sink dynamics but has not been well quantified for many plant and soil pools. This study applied a probabilistic inverse analysis of multiple observations to estimate mean residence times of carbon among three forest ecosystems in eastern China. Three assimilation experiments were conducted with either net ecosystem exchange data from eddy‐flux measurements or six biometric and soil data (i.e., foliage biomass, fine root biomass, woody biomass, litterfall, soil organic carbon, and soil respiration) or all data to evaluate their relative effectiveness on estimation of carbon residence times of different pools in a terrestrial ecosystem model. Estimated mean residence times of carbon ranged from 2 to 10 months for metabolic litter and microbial biomass pools, from 1 to 3 years for foliage, fine root biomass, and structural litter pools, and from 17 to 1361 years for woody biomass, slow and passive soil organic matter pools at three forest sites. The residence times of carbon were longer for leaf, litter and microbes pools but shorter for fine root and wood pools in the young evergreen coniferous plantation at Qianyanzhou site than the two mature mixed forests at Changbaishan and Dinghushan sites. Carbon residence times were well constrained for three plant pools and slow soil organic matter by biometric and soil data, whereas residence times for metabolic and structural litter, and microbial biomass pools were constrained by daily net ecosystem exchange data. Overall, our study demonstrated that biometric, soil and net ecosystem exchange data are complementary in constraining mean residence times of an ecosystem model.
A Simple Nested Simulation for SED-ML
Authors: Bergmann Frank
Published: March 2010

This document describes a simple nested Simulation Experiment for SED-ML [1] that is easy to implement and will help to broaden what SED-ML is able to encode.
Nonlinear electrodynamics of vortex matter in hard superconductors (Review)
Authors: Voloshin I. F. , Fisher L. M. , Yampol’skiĭ V. A.
Published: March 2010

Nontrivial electrodynamic properties of vortex matter, which are due to a specific nonlinearity of the material equations, in hard superconductors are discussed: collapse of the transport current and the static magnetization of superconductors by an external orthogonal ac magnetic field; appearance of jumps in the time dependence of the electric field at the boundary of a sample as a result of nonlinear interaction of waves having different frequencies; specific staged penetration of an electromagnetic field into anisotropic superconductors. Nonlocal effects resulting in a large modification of nonlinear phenomena are also examined. Special attention is given to a discussion of the unique phenomenon of macroturbulent instability, associated with the flow of Abrikosov vortices, in hard superconductors. Most results presented are based on original experimental and theoretical investigations performed with the participation of the present authors.
Features of the temperature dependence and magnetic-field dependence of the critical current density close to the critical temperature in YBa2Cu3O7−δ thin films
Authors: Kovalchuk D. G. , Chornomorets M. P. , Ryabchenko S. M. , Pashitskii E. A. , Semenov A. V.
Published: March 2010

The temperature dependence of the critical density of superconducting current jc(τ) [τ=(1−T∕Tc), and Tc is the critical temperature] of two epitaxial c-oriented YBa2Cu3O7−δ thin films grown on LaAlO3 and SrTiO3 substrates has been investigated by the method of dynamic magnetic susceptibility. In both samples, the jc(τ) dependence has two sections with power dependences jc∼τ3∕2 and jc∼τ2 in the temperature region from 77K to Tc, with crossover between them. Measurements were made of the temperature dependences of the dynamic relaxation rate Q(τ) (magnetic flux creep), which turned out to be unconnected with the observed crossovers. It is shown that the observed features of jc(τ) are not caused, as was assumed earlier, by the limitation of the critical depairing current density in the interdislocation gaps of the interblock boundaries of YBa2Cu3O7−δ epitaxial thin films. Based on numerical calculations, it is shown that the existence of crossovers and the breakdown of H∕τ scaling detected in one of the samples (H is the dc magnetic field) in the jc(τ,H) magnetic-field dependences close to Tc can be explained by the manifestation of macroscopic inhomogeneity of the samples in the local values of the critical temperature Tc (Tc inhomogeneity). The absence of observable breakdown of the H∕τ scaling in the second sample is explained by the smaller width of the distribution over Tc in it by comparison with the first sample.
Experience in numerically modelling the mixed state of superconductors, applied to a study of the nonstationary Schrödinger equation
Authors: Filippov A. E.
Published: March 2010

Experience in numerically modelling superconducting systems has been used to investigate the behavior of a nonstationary wave function far from equilibrium. It is shown that normalization of the wave function plays the role of an efficient nonlocal interaction that causes the wave function to be localized in one of the wells even for an infinitesimal difference of their depths. This fundamentally differs from the solution of the Fokker-Planck equation, which in equilibrium depends exponentially on the energy and is virtually symmetrical for wells that are similar in depth. When a fluctuational (small) variation causes the relative depths to reverse, the wave function’s maximum tunnels to the other well. A transition in a one-well potential from an excited state to a lower state is also considered. It is shown that this is accompanied by the emission of a localized segment of an electromagnetic wave, which can be identified with a “photon.”
Spin-glassy behavior and exchange bias effect of hexagonal YMnO3 nanoparticles fabricated by hydrothermal process
Authors: Zheng H. W. , Liu Y. F. , Zhang W. Y. , Liu S. J. , Zhang H. R. , Wang K. F.
Published: March 2010

Magnetic properties of hexagonal YMnO3 nanoparticles were systematically investigated. It is found that zero-field cooled and field-cooled magnetization display divergences at low temperature and a spin-glass temperature of TSG of 43 K are undergone. The thermoremanent magnetization further confirms the spin-glass feature of the YMnO3, which is related to the surface effects resulting in uncompensated spin and suppression of antiferromagnetic order. In particular, the exchange-bias effect is attributed to an exchange coupling between an antiferromagnetic core and the spin-glassy shell or ferromagnetic surface spins of the nanoparticles, which depends on the cooling field, is very interesting for nanomagnetic devices applications.
Nitric acid oxidation of Si method at 120 °C: HNO3 concentration dependence
Authors: Imamura Kentaro , Takahashi Masao , Asuha  , Hirayama Yasuhiro , Imai Shigeki , Kobayashi Hikaru
Published: March 2010

Electrical characteristics and physical properties of 8–10 nm silicon dioxide (SiO2) films formed on Si (100) substrates by use of the nitric acid oxidation of Si method at ∼120 °C have been investigated. The atomic density of the SiO2 layer increases with the HNO3 concentration. Fourier transformed infrared absorption measurements show that the higher the HNO3 concentration, the higher the atomic density of the SiO2 layer. From the Fowler–Nordheim plots, the barrier height at the SiO2/Si interface is found to increase with the HNO3 concentration. The leakage current density flowing through the SiO2 layer decreases with the HNO3 concentration employed for the SiO2 formation. It is concluded that the higher atomic density leads to SiO2 band-gap widening and thus to the higher band discontinuity energy at the SiO2/Si interface, which in turn results in a decrease in the tunneling probability of charge carries through SiO2. The density of oxide fixed charges decreases with an increase in the HNO3 concentration. When postmetallization annealing is performed at 250 °C in hydrogen atmosphere on the SiO2 layer formed with 68 wt % HNO3, electrical characteristics become as good as those of a thermally grown SiO2 layer formed at 900 °C.
Solving the thermal stability problem at the HfO2/Si interface with previous N implantation
Authors: Carazzolle M. F. , Flüchter C. R. , de Siervo A. , Pancotti A. , Weier D. , Schürmann M. , Westphal C. , Landers R. , Kleiman G. G.
Published: March 2010

We report on the use of N implantation to produce thin, pure, uniform, and thermally stable Si3N4 buffer layers and HfO2 overlayers on Si(100) and Si(111) without silicide formation.
Field effect modulation of ionic conductance of cylindrical silicon-on-insulator nanopore array
Authors: Joshi Punarvasu , Smolyanitsky Alex , Petrossian Leo , Goryll Michael , Saraniti Marco , Thornton Trevor J.
Published: March 2010

Results demonstrating the field effect modulation of ionic transport through an array of cylindrical nanopores fabricated in silicon-on-insulator substrates are presented. Pronounced modulation of the conductance is observed at low electrolyte concentrations when the electric double layers within the nanopores are overlapping. A numerical model based on Brownian dynamics reproduces the measured data.
Atomistic analysis of phase segregation patterning in binary thin films using applied mechanical fields
Authors: Nieves Alex M. , Vitek V. , Sinno T.
Published: March 2010

The patterned compositional evolution in thin films of a binary alloy controlled by modulated stress fields is studied by employing Monte Carlo simulations. General features of stress-patterned phase segregation are probed using a binary Lennard-Jones potential in which the lattice misfit between the two components of the alloy is varied systematically. In general, patterning of the microstructure is found to be more robust in the low-mismatch binary systems because large lattice mismatch promotes plastic, and therefore, irreversible relaxation, during annealing. It is shown that some control over the relaxation process can be achieved by careful design of the applied thermal annealing history. Additional calculations have been performed using two other potentials for binary metallic systems, an embedded-atom method (EAM) potential for Cu–Ag and a modified embedded-atom method (MEAM) potential for Cu–Ni that represent examples of high and low-mismatched systems, respectively. The results obtained with generic Lennard-Jones potentials are in excellent agreement with those from the EAM and MEAM potentials suggesting that it is possible to derive general guidelines for accomplishing stress-patterned segregation in a variety of thin films of binary alloys.
The role of carriers in spin current and magnetic coupling for ZnO:Co diluted magnetic oxides
Authors: Chou H. , Lin C. P. , Hsu H. S. , Sun S. J.
Published: March 2010

The role of carriers in the electric conduction and magnetic coupling of diluted magnetic oxides is essential to the spin current formation. This study elucidates the conduction of electrons originating from oxygen vacancies and the magnetic coupling between major doped transition ions. The findings indicate that electrons may conduct in the conduction band or by hopping within discrete localized states. Furthermore, because d-orbital of doped transition ions overlap with these localized states, only hopping electrons contribute to magnetic coupling and spin current formation. Those electrons in the conduction band have no observable effect on magnetic coupling.
Zeeman polarimetry measurement for edge current density determination using Li-beam probe on JT-60U
Authors: Kamiya K. , Fujita T. , Kojima A. , Kubo H.
Published: March 2010

Zeeman polarimetry system using Li-beam probe has been developed for the edge current density measurement in the JT-60U tokamak, which measures the polarization angle α (related to the pitch angle of the magnetic field) by means of photoelastic modulators, etalons, and phase sensitive detection using digital lock-in amplifiers with the accuracy in the α of Δα∼0.1°. The diagnostic has 20-channel viewing chords covering the plasma peripheral region of normalized minor radius r/a∼0.8–1 with a spatial resolution of up to ∼1 cm. Li-beam injection with beam current of up to ∼5 mA has been achieved. A new tuning method of the wavelength for the etalon has been demonstrated, scanning the beam acceleration voltage and keeping a beam current constant during a single shot. The peak wavelength of the etalon is adjusted in the direction to both blue- and redshifts by changing the angle of incidence and increasing the temperature, respectively. Time evolution of the edge current density profile has been determined for the current ramp experiment in the Ohmically heated discharges. In addition, the edge current density profile with the local peak of jped∼0.15–0.25 MA/m2 at r/a∼0.9 has been identified in the H-mode plasma, which is correlated with large pressure gradient in the pedestal region.
Plasma enhanced chemical vapor deposition of wear resistant gradual a-Si1−x:Cx:H coatings on nickel-titanium for biomedical applications
Authors: Niermann Benedikt , Böke Marc , Schauer Janine-Christina , Winter Jörg
Published: March 2010

Plasma enhanced chemical vapor deposition has been used to deposit thin films with gradual transitions from silicon to carbon on Cu, Ni, stainless steel, and NiTi. Thus show low stress, elasticity, and wear resistance with excellent adhesion on all metals under investigation. Already at low Si concentrations of 10 at. % the intrinsic stress is considerably reduced compared to pure diamondlike carbon (DLC) films. The deposition process is controlled by optical emission spectroscopy. This technique has been applied to monitor the growth precursors and to correlate them with the film composition. The compositions of the films were determined by Rutherford backscattering spectroscopy and XPS measurements. Due to the elastic properties of the gradual transition and the excellent biocompatibility of DLC, the described film systems present a useful coating for biomedical applications.
Accurate implementation of leaping in space: The spatial partitioned-leaping algorithm
Authors: Iyengar Krishna A. , Harris Leonard A. , Clancy Paulette
Published: March 2010

There is a great need for accurate and efficient computational approaches that can account for both the discrete and stochastic nature of chemical interactions as well as spatial inhomogeneities and diffusion. This is particularly true in biology and nanoscale materials science, where the common assumptions of deterministic dynamics and well-mixed reaction volumes often break down. In this article, we present a spatial version of the partitioned-leaping algorithm, a multiscale accelerated-stochastic simulation approach built upon the τ-leaping framework of Gillespie. We pay special attention to the details of the implementation, particularly as it pertains to the time step calculation procedure. We point out conceptual errors that have been made in this regard in prior implementations of spatial τ-leaping and illustrate the manifestation of these errors through practical examples. Finally, we discuss the fundamental difficulties associated with incorporating efficient exact-stochastic techniques, such as the next-subvolume method, into a spatial leaping framework and suggest possible solutions.
Thermoelectricity and localized f-band control by dp-hybridization on the Ce1−xCuxSe2 compounds
Authors: Rhyee Jong-Soo , Cho Eunseog , Lee Kyu Hyoung , Lee Sang Mock , Kim Hyun-sik , Kwon Yong Seung
Published: March 2010

We measured the temperature-dependent thermal conductivity κ(T), Seebeck coefficient S(T), and electrical resistivity ρ(T) of the polycrystalline Ce1−xCuxSe2 (x=0.0, 0.1, 0.2, and 0.3) series compounds. The high temperature thermoelectric property measurements of Ce0.9Cu0.1Se2 have shown that the maximum thermoelectric figure-of-merit (ZT) reached up to 0.18 at 800 K due to the large Seebeck coefficient (S≈344 μV/K) and relatively low thermal conductivity (κ=0.71 W m−1 K−1). By increasing the Cu-doping concentration (x≥0.2), the ZT is lowered mainly due to increasing the thermal conductivity. From the band structure calculation, the high Seebeck coefficient for the Ce0.9Cu0.1Se2 compound is attributed to the localized Ce f-band near the Fermi level due to Cu d- and Se p-orbital hybridization. The localized f-band has been shifted to a higher energy from the Fermi level with increased Cu-doping concentration, which is consistent with the decrease in the Seebeck coefficient. This research proposes that the orbital hybridization control on the layered structure rare-earth dichalcogenides is promising for high ZT thermoelectric materials development.
Energy level decay and excited state absorption processes in dysprosium-doped fluoride glass
Authors: Gomes Laércio , Librantz André Felipe Henriques , Jackson Stuart D.
Published: March 2010

The primary excited state decay processes relating to the H613/2→H615/2∼3 μm laser transition in singly Dy3+-doped fluoride (ZBLAN) glass have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the F69/2, H67/2 energy levels at 1125 nm and F611/2, H69/2 energy levels at 1358 nm established that the energy levels above the H611/2 level, excluding the F49/2 level, are entirely quenched by multiphonon emission in ZBLAN glass. The H611/2 and H613/2 energy levels emit luminescence with peaks at ∼1700 and ∼2880 nm, respectively, but at low quantum (luminescence) efficiencies. The quantum efficiency of the H611/2 level and H613/2 level is ∼9×10−5 and ∼1.3×10−2, respectively, for [Dy3+]=0.5 mol % based on calculations of the radiative lifetimes using the Judd–Ofelt theory. Excited state absorption (ESA) was detected by monitoring the rise time of the 1700 nm luminescence after tuning the probe wavelength across the spectral range from 1100 to 1400 nm. As a result of nonradiative decay of the higher excited states, ESA contributes to the heating of ∼3 μm fiber lasers based on Dy3+-doped fluoride glass. For [Dy3+] up to 4 mol %, we found no evidence of energy transfer processes between Dy3+ ions that influence the decay characteristics of the H611/2 and H613/2 energy levels.
Cyanide-bridged RuxNi3-3x/2[Cr(CN)6]2⋅zH2O molecular magnets: Controlling structural disorder and magnetic properties by a 4d ion (ruthenium) substitution
Authors: Yusuf S. M. , Thakur N. , Kumar A. , Yakhmi J. V.
Published: March 2010

We report the effect of a 4d ion (Ru3+) substitution on structural disorder and magnetic ordering in the cyanide-bridged molecular magnets, RuxNi3-3x/2[Cr(CN)6]2⋅zH2O (0≤x≤0.5). Structural analysis, by employing Rietveld refinement of x-ray diffraction patterns, reveals a face centered cubic structure for all these compounds. In the present study, we have controlled the [Cr(CN)6] vacancies by substituting Ru at the Ni site and then the role of varying [Cr(CN)6] vacancies on the structural correlations and consequently on the magnetic properties has been investigated. We have succeeded in increasing the magnetic ordering temperature (TC) with increasing Ru concentration up to x=0.2. The IR spectra of the Ru doped compounds indicate the presence of Cr2+–C≡N–Ru4+ type sequences amounting to an additional structural disorder. The magnetic Bragg scattering in the neutron diffraction patterns is masked by a large diffuse scattering arising due to the structural disorder. The reverse Monte Carlo calculations quantify the total structural disorder, which enhances with increasing x. With x>0.2, a combined effect of the stronger magnetic interaction between the 3d/4d-3d spin carriers (due to reduction in vacancies) and the reduction in the average spin of the Ru/Ni site leads to a decrease in the TC. An antiferromagnetic coupling of Ru3+ (low spin, S=1/2) moments with both Ni2+ (S=1) and Cr3+ (S=3/2) moments is found. The present study thus gives a pathway for designing new molecular magnets by controlling vacancies, which leads to a tuning of the intertwined structural and magnetic properties.
Optimization of piezoelectric properties for [001]c poled 0.94Pb(Zn1/3Nb2/3)O3–0.06PbTiO3 single crystals
Authors: Xiang Yang , Zhang Rui , Cao Wenwu
Published: March 2010

The piezoelectric properties of [001]c poled 0.94Pb(Zn1/3Nb2/3)O3–0.06PbTiO3 single crystals were greatly enhanced by controlling their domain configurations. Contrary to the interpretation of charged domain walls being the main contributor to the piezoelectric enhancement, we found that smaller domain size and more neutral domain walls were the main contributors for the piezoelectric enhancement of these multidomain crystals. The properties of 109° neutral domain walls in 0.94Pb(Zn1/3Nb2/3)O3–0.06PbTiO3 single crystals were extracted by using a piezoelectric domain wall model.
Host and adsorbate dynamics in silicates with flexible frameworks: Empirical force field simulation of water in silicalite
Authors: Bordat Patrice , Cazade Pierre-André , Baraille Isabelle , Brown Ross
Published: March 2010

Molecular dynamics simulations are performed on the pure silica zeolite silicalite (MFI framework code), maintaining via a new force field both framework flexibility and realistic account of electrostatic interactions with adsorbed water. The force field is similar to the well-known “BKS” model [B. W. H. van Beest et al., Phys. Rev. Lett. 64, 1955 (1990)], but with reduced partial atomic charges and reoptimized covalent bond potential wells. The present force field reproduces the monoclinic to orthorhombic transition of silicalite. The force field correctly represents the hydrophobicity of pure silica silicalite, both the adsorption energy, and the molecular diffusion constants of water. Two types of adsorption, specific and weak unspecific, are predicted on the channel walls and at the channel intersection. We discuss molecular diffusion of water in silicalite, deducing a barrier to crossing between the straight and the zigzag channels. Analysis of the thermal motion shows that at room temperature, framework oxygen atoms incurring into the zeolite channels significantly influence the dynamics of adsorbed water.
Laser generated guided waves and finite element modeling for the thickness gauging of thin layers
Authors: Lefevre F. , Jenot F. , Ouaftouh M. , Duquennoy M. , Ourak M.
Published: March 2010

In this paper, nondestructive testing has been performed on a thin gold layer deposited on a 2 in. silicon wafer. Guided waves were generated and studied using a laser ultrasonic setup and a two-dimensional fast Fourier transform technique was employed to obtain the dispersion curves. A gold layer thickness of 1.33 μm has been determined with a ±5% margin of error using the shape of the two first propagating modes, assuming for the substrate and the layer an uncertainty on the elastic parameters of ±2.5%. A finite element model has been implemented to validate the data post-treatment and the experimental results. A good agreement between the numerical simulation, the analytical modeling and the experimentations has been observed. This method was considered suitable for thickness layer higher than 0.7 μm.
Permutability of Backlund transformations for N=2 supersymmetric sine-Gordon
Authors: Gomes J. F. , Ymai L. H. , Zimerman A. H.
Published: March 2010

The permutability of two Backlund transformations is employed to construct a nonlinear superposition formula and to generate a class of solutions for the N=2 super sine-Gordon model. We present explicitly the one and two soliton solutions.
Extraordinary transmission in the ultraviolet range from subwavelength slits on semiconductors
Authors: Vincenti M. A. , de Ceglia D. , Buncick M. , Akozbek N. , Bloemer M. J. , Scalora M.
Published: March 2010

In this paper, we describe a way to achieve the extraordinary transmission regime well into the UV range using subwavelength slits carved on semiconductor substrates. Unlike metals, the dielectric permittivity of typical semiconductors like GaAs or GaP is negative beginning in the extreme UV range (λ≤270 nm) and is characterized by large absorption. We show that the metallike response of bulk semiconductors exhibits surface plasmon waves that lead to extraordinary transmission in the UV and soft x-ray ranges, in spite of the large absorption. The importance of realistic material response versus perfect conductors is also discussed. We show that the use of perfect conductor boundary conditions can lead to field amplitudes that may be underestimated by several orders of magnitudes. These findings may be important in high resolution photolithography, near-field optical devices, and ultrahigh density optical storage in wavelength ranges, where it may not be possible to utilize more traditional plasmonic materials like noble metals.
Entropy change linked to the magnetic field induced martensitic transformation in a Ni–Mn–In–Co shape memory alloy
Authors: Recarte V. , Pérez-Landazábal J. I. , Kustov S. , Cesari E.
Published: March 2010

Experimental results on the temperature dependence of the entropy change induced by magnetic field in a Ni–Mn–In–Co ferromagnetic shape memory alloy have been analyzed. Different behaviors of the entropy change ΔS versus temperature have been observed, depending on the value of polarizing magnetic field. In addition, the magnetocaloric effect shows over certain temperature range, a limit value corresponding to the transformation entropy ΔStr. To explain the experimental results, a model, which takes into account the value of the martensitic transformation temperature shift and the transformation temperature range, has been proposed. The model allows to estimate the entropy change as a function of temperature and applied magnetic field from a few experimental data and therefore a first estimation of the refrigerant capacity of the system can be done.
A reconfigurable plasma antenna
Authors: Kumar Rajneesh , Bora Dhiraj
Published: March 2010

An experiment aimed at investigating the antenna properties of different plasma structures of a plasma column as a reconfigurable plasma antenna, is reported. A 30 cm long plasma column is excited by surface wave, which acts as a plasma antenna. By changing the operating parameters, e.g., working pressure, drive frequency, input power, radius of glass tube, length of plasma column, and argon gas, single plasma antenna (plasma column) can be transformed to multiple small antenna elements (plasma blobs). It is also reported that number, length, and separation between two antenna elements can be controlled by operating parameters. Moreover, experiments are also carried out to study current profile, potential profile, conductivity profile, phase relations, radiation power patterns, etc. of the antenna elements. The effect on directivity with the number of antenna elements is also studied. Findings of the study indicate that entire structure of antenna elements can be treated as a phased array broadside vertical plasma antenna, which produces more directive radiation pattern than the single plasma antenna as well as physical properties and directivity of such antenna can be controlled by operating parameters. The study reveals the advantages of a plasma antenna over the conventional antenna in the sense that different antennas can be formed by tuning the operating parameters.
Effect of composition and chemical bonding on the band gap and band offsets to Si of HfxSi1−xO2 (N) films
Authors: Geppert I. , Lipp E. , Brener R. , Hung S. , Eizenberg M.
Published: March 2010

The energy band gap, alignment with Si and the chemical bonding of 3–4 nm thick HfxSi1−xO2 films with 0≤x≤1 were investigated as a function of composition. Nitrogen was introduced by N plasma incorporation into HfxSi1−xO2 films with x=0.3, 0.5, and 0.7 grown on a SiO2/Si stack by metal-organic chemical vapor deposition. The structure of the dielectric films was characterized by high resolution transmission electron microscopy. X-ray photoelectron spectroscopy was used to determine the band gap, as well as the energy band alignment with Si and the chemical structure of the films. The amount of Si in the films and the incorporated N were found to influence the band gap and the band alignment with Si. The band gap was found to gradually decrease with the increase in Hf content, from a value of 8.9 eV (for pure SiO2) to a value of 5.3 eV (for pure HfO2). These changes were accompanied by a reduction of the valance band offset relative to the Si substrate, from a value of 4.8 eV (for pure SiO2) to a value of 1.5 eV (for pure HfO2). In addition, we have found that the presence of Hf–N bonds increases the conduction band offset from a value of 2.7 eV, which was obtained when only Hf–O bonds are present, to a value of 3.1 eV. The changes in the band structure and band alignment of Hf-silicate films are explained based on the chemical structure of the nitrided Hf-silicate films.
The optimal elastic flagellum
Authors: Spagnolie Saverio E. , Lauga Eric
Published: March 2010

Motile eukaryotic cells propel themselves in viscous fluids by passing waves of bending deformation down their flagella. An infinitely long flagellum achieves a hydrodynamically optimal low-Reynolds number locomotion when the angle between its local tangent and the swimming direction remains constant along its length. Optimal flagella therefore adopt the shape of a helix in three dimensions (smooth) and that of a sawtooth in two dimensions (nonsmooth). Physically, biological organisms (or engineered microswimmers) must expend internal energy in order to produce the waves of deformation responsible for the motion. Here we propose a physically motivated derivation of the optimal flagellum shape. We determine analytically and numerically the shape of the flagellar wave which leads to the fastest swimming for a given appropriately defined energetic expenditure. Our novel approach is to define an energy which includes not only the work against the surrounding fluid, but also (1) the energy stored elastically in the bending of the flagellum, (2) the energy stored elastically in the internal sliding of the polymeric filaments which are responsible for the generation of the bending waves (microtubules), and (3) the viscous dissipation due to the presence of an internal fluid. This approach regularizes the optimal sawtooth shape for two-dimensional deformation at the expense of a small loss in hydrodynamic efficiency. The optimal waveforms of finite-size flagella are shown to depend on a competition between rotational motions and bending costs, and we observe a surprising bias toward half-integer wave numbers. Their final hydrodynamic efficiencies are above 6%, significantly larger than those of swimming cells, therefore indicating available room for further biological tuning.
The ground X Σ1g+ electronic state of the cesium dimer: Application of a direct potential fitting procedure
Authors: Coxon John A. , Hajigeorgiou Photos G.
Published: March 2010

A collection of 16 544 fluorescence series spectroscopic line positions involving the A Σ1u+→X Σ1g+ transition in Cs2 has been analyzed by a modern direct potential fitting procedure to generate the first fully analytical potential energy function for the ground electronic state, and precise energy term values for the excited A Σ1u+ state. The potential function yields an accurate representation of spectroscopic data that span 99.24% of the well depth and the number of fitted parameters is significantly less than half the number of parameters determined in conventional Dunham analyses. A novel variant of the Morse/long-range potential model has been employed in the representation of the ground state potential, and a critical comparison has been made with an extended modified Lennard-Jones potential model. Proper account has been taken of the known long-range van der Waals form of the potential, and our final potential function is determined with constrained literature values of the C8 and C10 dispersion energy coefficients, along with a fitted value of C6=3.31(5)×107 cm−1 Å6=6870(100) a.u. The fitted dissociation energy (De) is compared with the precisely known value based on the recent analysis of data from a two-photon transfer process (STIRAP) in ultracold Cs atoms. It is concluded that hyperfine effects in the X Σ1g+ state are not negligible, and that the estimate of De=3649.84(7) cm−1 obtained in this work represents an effective dissociation limit lying between the two lowest hyperfine limits. Precise rotational and centrifugal distortion constants for the ground electronic state have also been calculated through conventional perturbation theory. These estimates are fully consistent with the derived potential function and the experimental spectroscopic information.
Note: Effects of several thermal glues used on temperature dependent Hall measurements
Authors: Rangel-Kuoppa Victor-Tapio , Chen Gang
Published: March 2010

The effects of four thermal glues (cry-con©, fixogum©, RS 503-357©, and silicon-high vacuum-grease from Leybold vacuum©) on temperature dependent Hall measurements on n-type silicon are tested. All thermal glues yielded the same results (resistivity, mobility, and charge carrier density) between 300 and 190 K. The use of RS 503-357© drastically distorts the expected results below 190 K, probably due to a phase transition and its latent heat, which affects the sample temperature during the phase transition. All the other thermal glues give reproducible results down to 100 K. Below 100 K, the use of cry-con©, fixogum©, and the silicon-high vacuum-grease from Leybold vacuum© yield decreasing mobility and charge carrier density and increasing resistivity, as temperature decreases, but with different magnitudes. This is explained as the thermal properties of each glue start to diverge. Fixogum© seems to give the best thermal conductivity, while the silicon-high vacuum grease from Leybold vacuum performs the worst below 100K. Crycon© has an intermediate behavior between these two former ones. Cooling speed plays an important role at these low temperatures.