bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of the Efficacy of a Psychological Treatment for Women Victims of Violence by their Intimate Male Partner
Authors: Crespo María , Arinero María
Published: March 2013

This study evaluates the long-term efficacy of a brief psychotherapeutic cognitive-behavioral program in group format for female victims of violence by their intimate partner. 53 battered women were randomized into one of two intervention programs: one including among others exposure technique (n = 28) and another one in which exposure procedures were substituted by communication skills training (n = 25). Additionally, both programs included: psycho-education, breath control, training to improve self-esteem, cognitive restructuring, problem-solving, planning pleasant activities, and relapse prevention. The treatment was carried out in 8 weekly sessions. Measures of posttraumatic symptoms, anxiety, depression, self-esteem and anger expression were analyzed at pre- and post-treatment, and at 1-, 3-, 6- and 12-months follow-ups. Results show a pronounced decrease of posttraumatic, depressive and anxiety symptoms, which maintained in the different measure moments, with scarce difference between the two programs. The results and their clinical implications are discussed.
Therapists' Verbal Behavior Analysis: A Descriptive Approach to the Psychotherapeutic Phenomenon
Authors: Froján M. Xesús , Montaño Montserrat , Calero Ana
Published: March 2013

This paper presents some preliminary results from a different approach to research on psychotherapeutic processes. As activity in psychotherapy is predominantly verbal, we propose a scientific study of therapists' verbal behavior from a behaviorist perspective. Data were obtained through observational analysis of the recordings of 16 clinical sessions involving 4 cases, all of which based on individual cognitive-behavioral therapy with adults, in the framework of private clinical practice in Spain. The analysis used a previously validated system of categories andThe Observer XTsoftware to register and code data. A descriptive analysis enabled us to identify several patterns of psychologists' verbal behavior, irrespective of the therapist and/or the case analyzed. Notable differences were also observed in clinicians' performance, which raises important questions about potential variables associated with therapeutic change. Finally, we discuss the strengths and weaknesses of the present research agenda, the development of which should lead to a fuller understanding of the psychotherapeutic phenomenon.
Psychometric Properties of the Social Phobia and Anxiety Inventory for Children in a Spanish Sample
Authors: Olivares José , Sánchez-García Raquel , López-Pina José Antonio , Rosa-Alcázar Ana Isabel
Published: March 2013

The objectives of the present study were to adapt and analyze the factor structure, reliability, and validity of the Social Phobia and Anxiety Inventory for Children (SPAI-C; Beidel, Turner, & Morris, 1995) in a Spanish population. The SPAI-C was applied to a sample of 1588 children and adolescents with ages ranging from 10 to 17 years. The confirmatory factor analysis (CFA) showed a four-factor structure: Public performance, Assertiveness, Fear and avoidance/escape in social encounters, and Cognitive and psychophysiological interferences. Internal consistency was high (.90) and test-retest reliability was moderate (.56). Significant differences were found in the variables sex and age, although the effect size was small in both variables and their interaction. Overall, the increase of the age value was inversely proportional to that of social anxiety measured with the SPAI-C; in participants of the same age, values were higher for girls than for boys. Results suggest that the Social Phobia and Anxiety Inventory For Children is a valid and reliable instrument to assess social anxiety in Spanish children and adolescents.
The Social Phobia Inventory: Screening and Cross-Cultural Validation in Spanish Adolescents
Authors: Garcia-Lopez Luis Joaquín , Bermejo Rosa Mª , Hidalgo Mª Dolores
Published: March 2013

Availability of brief, self-report measures to be used as screening instruments is crucial to detect correctly youth with social anxiety disorder and therefore, reach those otherwise under-detected and under-treated. A previous study revealed that the Social Phobia Inventory (SPIN) was potentially an appropriate measure for screening social anxiety among US adolescents. However, there is a lack of information concerning its properties as a screening test in other cultures and languages. This is the main objective of this study, although further validity of the scale is provided as well. The sample consisted of 192 adolescents (a sample composed of 114 subjects with a principal diagnosis of social anxiety disorder; and a group consisting of 78 subjects with no diagnosis of social phobia). Results suggest that the Social Phobia Inventory has demonstrated good psychometric properties and indeed may be used as a screening tool in Spanish-speaking adolescents.
Psychometric Properties of the Children's Depression Inventory in Community and Clinical Sample
Authors: Masip Anna Figueras , Amador-Campos Juan Antonio , Gómez-Benito Juana , Gándara Victoria del Barrio
Published: March 2013

The psychometric characteristics of the Children's Depression Inventory, CDI (Kovacs, 1992) in a sample of 1705 participants (792 boys and 913 girls) and a clinical sample of 102 participants (42 boys and 60 girls) between 10 and 18 years old are presented. Reliability coefficients range, for both samples, from .82 (test) to .84 (retest) in the community sample, and .85 (test, clinical sample); test-retest reliability is .81 in the community sample. The mean scores are similar to other Spanish and English ones. Girls score higher than boys. The cut-off point that best differentiates between depressive and community participants is 19, with a sensitivity of 94.7%, a specificity of 95.6%, a positive predictive value of .90, and a negative predictive value of .98.
Elaboration and Validation of the Athletes Idiocentric and Allocentric Profile Inventory (I-A Profile)
Authors: de Melo Gislane Ferreira , Giavoni Adriana
Published: March 2013

The athlete's psychological profile is one of the most studied areas in sport psychology, but there is no consensus in this area. The purpose of this study was to elaborate and validate a scale to measure and classify athletes into a Idiocentric-Alocentric profile. The method was split in two phases: a) Items elaboration and theoretical model and b) Validation. Qualitative analyses were performed during the first phase and factorial analysis and Cronbach's Alpha were used to validate the instrument. The final instrument was composed by 27 items and the factorial structure showed three factors for Idiocentrism (Self-Realization & Competitiveness, Hedonism, Team Emotional Distance and a second order factor – Idiocentrism Level) and one factor for the Alocentrism (Alocentrism Level). It was concluded that the pattern and consistency of the results indicate that this inventory could be used as a reliable research tool in Brazilian sports context.
Lerdahl and Jackendoff's Grouping Structure Rules in the Performance of a Hindemith Sonata
Authors: Ordoñana Jose A. , Laucirica Ana
Published: March 2013

In the last decades, musical cognitive psychology has intervened to build a bridge towards the comprehension of musical structures. The present paper studies the behavior of several students and music professionals in relation to grouping structure and it does so through the performance analysis of the first movement of Hindemith's sonata for flute and piano, according to the rules formulated by Lerdahl and Jackendoff, movement chosen because of its tonal ambiguity. The participants of this experiment are three medium level female Conservatory students. They performed the aforementioned piece after studying it for a whole trimester. The performance of the same piece by three professional musicians was also analyzed, using the appropriate commercial recordings for this purpose. This analysis includes the choice of group limits used in performance by both professionals and students and the comparison of both groups' results. Differences were observed in the placement of said limits by the different groups but all of them respected the set of rules formulated by Lerdahl and Jackendoff.
Goals during Adolescence and their Relationship with Antisocial Behavior
Authors: López-Romero Laura , Romero Estrella
Published: March 2013

In recent years, psychological research has emphasized the role of goals in adolescent development and, particularly, in the development of socially adapted lifestyles. Along those lines, the present study, analyzing data collected from a sample of 488 participants, explores: a) The structure of adolescent goals and their importance for young people, b) The relationship between adolescent goals and antisocial behavior and c) The role of gender in this relationship. The results show that adolescent goals are structured according to 6 factors: Social Recognition, Emancipation, Education, Physical-Athletic, Antisocial and Interpersonal-Familial. Educational and emancipative goals appear to be most important for young people. In addition, it has been found that there are significant correlations between certain types of goals and adolescent antisocial behavior, as well as significant gender differences. The data reflect the need to incorporate motivational dimensions into explanatory models of adolescent behavioral problems.
The Psychological Adjustment of Children with Asthma: Study of Associated Variables
Authors: Lima Lígia , Guerra Marina Prista , de Lemos Marina Serra
Published: March 2013

As part of a larger research project aimed to understand the impact of asthma in the psychological adjustment of children, this study focuses in the identification of factors associated with this process. The sample of this study consisted of 89 children, aged 8 to 12 with physician diagnosed asthma. To assess children's adjustment, the Portuguese versions of the following instruments were used: School-age Temperament Inventory (McClowry, 1995) Schoolagers Coping Strategies Inventory (Ryan-Wenger, 1990); Pediatric Quality of Life Inventory – PedsQL (Varni, Seid & Kurtin, 2001); The Self-perception Profile for Children (Harter, 1985), Child Behavior Checklist (Achenbach,1991); Social Skills Rating System (Gresham & Elliot, 1990). The results revealed that negative reactivity predicts the level of anxiety/depression, task persistence and perceived coping efficacy predicts social skills and that self-esteem is a significant predictor of the perceived quality of life. A significant proportion of shared variance was also found what seems to confirm the existence of multi-determination in the process of adjustment. The main conclusion is that two dimensions of temperament (negative reactivity and task persistence), as well as perceived coping efficacy and self-esteem, play a significant role in influencing the psychological adjustment of children with asthma.
Effects of Family Psychoeducation on Expressed Emotion and Burden of Care in First-Episode Psychosis: A Prospective Observational Study
Authors: González-Blanch César , Martín-Muñoz Vanessa , Pardo-García Gema , Martínez-García Obdulia , Álvarez-Jiménez Mario , Rodríguez-Sánchez José Manuel , Vázquez-Barquero José Luis , Crespo-Facorro Benedicto
Published: March 2013

The present study aimed to examine the levels and interactions of family burden (FB) and expressed emotion (EE) in first episode psychosis (FEP) patients and, secondly, to observe the potential change after a brief psychoeducational group intervention implemented in a real world clinical setting. Twenty-three key relatives of FEP patients received a brief psychoeducational group intervention. FB and EE were assessed before and after the intervention. EE-change and correlations between variables were examined. Half of the sample of key-relatives showed high levels of EE. No severe family burden was observed. FB and EE did not change after the intervention. Family subjective and objective burden were correlated with emotional overinvolvement, but not with criticism. Brief psychoeducational groups may not be sufficient to reduce FB and EE associated to the experience of caregiving for a family member with a first-episode psychotic disorder.
Effect of the EMDR Psychotherapeutic Approach on Emotional Cognitive Processing in Patients with Depression
Authors: Uribe Myrna Estela Rosas , Ramírez Ernesto O. López , Mena Ignacio Jarero
Published: March 2013

The current investigation, framed within the emotional cognitive science field, was conducted with three patients with major depression. They participated in a therapeutic process which involved EMDR (Eye Movement Desensitization and Reprocessing). Data were obtained in the clinical practice through a longitudinal one subject study design, including: emotional valence identification within affective priming experiments; and depressive emotional representation studies, the data of which was analyzed using multi-dimensional scaling. The first ones had the purpose of observing the therapeutic impact over the emotional cognitive bias mechanism regarding depresogenic words related to traumatic experiences; and the second, to analyze modifications on depressive schemata. The results showed that EMDR had a positive effect both on emotional cognitive processing and on long-term memory conceptual organization. In the discussion section, interesting remarks are made on the incorporation of emotional cognitive science tools to the EMDR clinical practice.
Psychiatric Patient Disposition Agreement Between the Emergency Physician and the Psychiatry Consultant
Authors: Chakravarthy Bharath , Menchine Michael , Thompson Daniel E. , Rajeev Sindhya , Santos Barbara-Jean
Published: March 2013

Background: Mental illness is prevalent, disabling, and costly. Emergency department (ED) visits for mental health-related reasons are on the increase. Aims: Determine the level of agreement between emergency physicians and psychiatrists regarding psychiatric patient disposition. Method: We conducted a prospective, observational study at a private university hospital ED from October 2008–April 2009 using a convenience sample of patients of all ages with psychiatric complaints who received formal psychiatric consultation during their ED visit. The emergency physician completed a data sheet prior to psychiatric consultation, assessing the likelihood of admission for psychiatric evaluation. We evaluated the positive predictive value (PPV) and negative predictive value (NPV) of the emergency physician admission decision for all patients before psychiatric consultation, compared with the patients’ actual disposition as determined by the consulting psychiatrist. Results: The study captured 230 subjects, 53% of whom were suicidal patients. 74% of patients were eventually admitted. The emergency physician decision to admit for inpatient psychiatric evaluation had a PPV of 87.3% (CI 81.4–91.9%) and an NPV of 66.7% (CI 52.9–78.6%) compared to the psychiatrist decision for the total sample, and a PPV of 90% (CI 82.4–95.1%) and an NPV of 69.6% (CI 47.1–86.8%) for suicidal patients. Additionally, the κ score, a measure of agreement between emergency physician disposition decision and psychiatrist disposition decision, was 0.530 (Cl 0.404–0.656). 95% of patients with an ED assessment of “definitely admit” were eventually admitted by the psychiatrist. Conclusion: Emergency physician disposition has a high PPV (87.3%) and a moderate NPV (66.7%) compared to psychiatrist disposition.
The Relationship Between Portrayals of Nonsuicidal Self-Injury, Attitudes, Knowledge, and Behavior
Authors: Radovic Sara , Hasking Penelope
Published: March 2013

Background: The high prevalence of nonsuicidal self-injury (NSSI) among young people has prompted research into why this may be a chosen coping strategy. One possibility is that the behavior is modeled from media depictions. Aims: The study examined the relationship between viewing films featuring NSSI and an individuals’ knowledge, attitudes toward, and engagement in NSSI. Method: 317 individuals (18–30 years) completed an online survey measuring these key variables. Results: Exposure to NSSI in film was related to history of NSSI; an even stronger relationship emerged when individuals identified with the character. Films increase knowledge and empathy toward those engaging NSSI, but they may also serve to trigger NSSI. Conclusions: Portrayal of NSSI in film could be designed to minimize imitation and to consider the potential to increase knowledge of NSSI among those with little exposure to the behavior. However, because films may also trigger NSSI, further work is needed to determine under what circumstances, and for which individuals, films exert a protective or harmful effect.
Teaching Words to Adolescents With Language Disabilities
Authors: Montgomery Judy K.
Published: March 2013

Vocabulary development occurs throughout our lives; thus, adolescents—a challenging population to teach or remediate—are simply in the middle of this word-acquisition process. Strategies for this age group must address word learning in creative ways. In this article, the author proposes three intervention strategies for adolescents with language disabilities that link to the Common Core State Standards, academic content expectations, and salient features of the English language.
Analysis of the control limit for rotor‐side converter of doubly fed induction generator‐based wind energy conversion system under various voltage dips
Authors: Xiao Shuai , Geng Hua , Zhou Honglin , Yang Geng
Published: March 2013

For the grid‐connected doubly‐fed induction generator (DFIG)‐based wind energy conversion system (WECS), many improved control algorithms have been developed for the rotor‐side converter (RSC) to suppress the overcurrents in the rotor‐side under voltage dips. However, such objective can hardly be achieved under severe grid fault conditions because of the limitation of RSCs output voltage. An analysis tool is proposed to estimate the the theoretical control limit of the RSC in suppressing the short‐circuit rotor currents during grid faults in this study. The tool is based on the optimisation theory and takes the practical constraints of the RSC into account. To execute the analysis, a simplified DFIG model with decoupled stator and rotor fluxes is presented, and the low‐voltage ride through (LVRT) problem can be formulated as an optimisation problem, which intends to suppress the rotor winding currents with voltage constraints. The Pontryagin's minimum principle is employed to solve the optimisation problem and the results can identify the control limit of the RSC. A case study based on a typical 1.5 MW DFIG‐based WECS under various grid voltage dips is carried out to validate the analytical method. The proposed method is also further verified by experimental tests on a scaled 3 KW DFIG system. The results are expected to help the manufacturers to assess and improve their RSC controllers or LVRT measures.
Design of a new reactor-like high temperature near ambient pressure scanning tunneling microscope for catalysis studies
Authors: (Feng) Tao Franklin , Nguyen Luan , Zhang Shiran
Published: March 2013

Here, we present the design of a new reactor-like high-temperature near ambient pressure scanning tunneling microscope (HT-NAP-STM) for catalysis studies. This HT-NAP-STM was designed for exploration of structures of catalyst surfaces at atomic scale during catalysis or under reaction conditions. In this HT-NAP-STM, the minimized reactor with a volume of reactant gases of ∼10 ml is thermally isolated from the STM room through a shielding dome installed between the reactor and STM room. An aperture on the dome was made to allow tip to approach to or retract from a catalyst surface in the reactor. This dome minimizes thermal diffusion from hot gas of the reactor to the STM room and thus remains STM head at a constant temperature near to room temperature, allowing observation of surface structures at atomic scale under reaction conditions or during catalysis with minimized thermal drift. The integrated quadrupole mass spectrometer can simultaneously measure products during visualization of surface structure of a catalyst. This synergy allows building an intrinsic correlation between surface structure and its catalytic performance. This correlation offers important insights for understanding of catalysis. Tests were done on graphite in ambient environment, Pt(111) in CO, graphene on Ru(0001) in UHV at high temperature and gaseous environment at high temperature. Atom-resolved surface structure of graphene on Ru(0001) at 500 K in a gaseous environment of 25 Torr was identified.
Origin of high piezoelectric response in A-site disordered morphotropic phase boundary composition of lead-free piezoelectric 0.93(Na0.5Bi0.5)TiO3–0.07BaTiO3
Authors: Maurya Deepam , Murayama M. , Pramanick A. , Reynolds W. T. , An Ke , Priya Shashank
Published: March 2013

Perovskite piezoelectric compositions near the morphotropic phase boundary (MPB) are known to exhibit high piezoelectric response. In lead-based ABO3 compound with B-site disorder, the origin of this enhancement has been associated with the presence of an intermediate monoclinic/orthorhombic state that bridges the adjacent ferroelectric rhombohedral and tetragonal phases. However, the origin of high piezoelectric response in lead-free ABO3 compounds with A-site disorder has not been conclusively established. We describe a microscopic model derived from comparative analyses of high resolution transmission electron microscopy and neutron diffraction that explains the origin of high piezoelectric response in lead-free MPB compositions of 0.93(Na0.5Bi0.5)TiO3–0.07BaTiO3. Direct observation of nanotwins with monoclinic symmetry confirmed the presence of an intermediate bridging phase that facilitates a pathway for polarization reorientation. Monoclinic distortions of an average rhombohedral phase are attributed to localized displacements of atoms along the non-polar directions.
Formation of a ZnO2 layer on the surface of single crystal ZnO substrates with oxygen atoms by hydrogen peroxide treatment
Authors: Kashiwaba Y. , Abe T. , Nakagawa A. , Niikura I. , Kashiwaba Y. , Daibo M. , Fujiwara T. , Osada H.
Published: March 2013

Formation of a ZnO2 layer by H2O2 treatment for single crystal ZnO (0001) substrates was studied. X-ray diffraction (XRD) peaks of ZnO2 with a pyrite structure were observed in XRD 2θ-ω scan patterns of the O-face of single crystal ZnO (0001) substrates with H2O2 treatment, but these peaks were not observed in patterns of the Zn-face of ZnO (0001) substrates with H2O2 treatment. XRD ω scan patterns of the ZnO (0002) plane of the O-face of single crystal ZnO (0001) substrates were broadened at the tail of the pattern by H2O2 treatment, but such broadening was not observed in that plane of the Zn-face. Grain structure of ZnO2 layers was clearly observed in atomic force microscopy (AFM) images for the O-face of ZnO (0001) substrates with H2O2 treatment. Spectra of X-ray photoelectron spectroscopy (XPS) of the O-face of ZnO (0001) substrates with H2O2 treatment showed a definite peak shift of the O 1s peak. It is thought that a pyrite structure of ZnO2 is easily formed around an O atom of the O-face of ZnO (0001) substrates. Results of XRD measurements, the AFM image, and XPS measurement of the H2O2-treated single crystal ZnO (101¯0) substrate that has oxygen atoms on the surface appeared to be the same as those of the O-face of ZnO (0001) substrates.
Theoretical study of the vibrational relaxation of the methyl radical in collisions with helium
Authors: Ma Qianli , Dagdigian Paul J. , Alexander Millard H.
Published: March 2013

We report a theoretical investigation of the relaxation of the umbrella vibrational mode (the ν2 mode) of the CH3 molecule in its ground \documentclass[12pt]{minimal}\begin{document}$\tilde{X}^2A_2^{\prime \prime }$\end{document}X̃2A2′′ electronic state in collisions with helium. We have calculated a four-dimensional potential energy surface (PES) for the interaction between CH3 with different umbrella displacements and a helium atom, using a restricted open-shell coupled-cluster method with inclusion of all single, double, and (perturbatively) triple excitations [RCCSD(T)]. With this PES we carried out full close-coupling scattering calculations including all CH3 umbrella-rotational levels with v2 ⩽ 3. To our knowledge, this work represents the first fully quantum calculations of ro-vibrational relaxation of a polyatomic. In more detail, we investigate propensities in the calculated ro-vibrational cross sections and the dependence on initial rotational excitation, as well as determining thermal rate constants. Overall, ro-vibrational relaxation is nearly two orders of magnitude less efficient than pure-rotational relaxation, with a noticeable dependence on the initial rotational level. We predict the room temperature v2 = 1 vibrational relaxation rate constant to be 5.4 × 10−12 cm3 molecule−1 s−1, compared to the rate constants for pure-rotational relaxation of the lower rotational levels (∼2.0 × 10−10 cm3 molecule−1 s−1).
Microscopic theory of singlet exciton fission. I. General formulation
Authors: Berkelbach Timothy C. , Hybertsen Mark S. , Reichman David R.
Published: March 2013

Singlet fission, a spin-allowed energy transfer process generating two triplet excitons from one singlet exciton, has the potential to dramatically increase the efficiency of organic solar cells. However, the dynamical mechanism of this phenomenon is not fully understood and a complete, microscopic theory of singlet fission is lacking. In this work, we assemble the components of a comprehensive microscopic theory of singlet fission that connects excited state quantum chemistry calculations with finite-temperature quantum relaxation theory. We elaborate on the distinction between localized diabatic and delocalized exciton bases for the interpretation of singlet fission experiments in both the time and frequency domains. We discuss various approximations to the exact density matrix dynamics and propose Redfield theory as an ideal compromise between speed and accuracy for the detailed investigation of singlet fission in dimers, clusters, and crystals. Investigations of small model systems based on parameters typical of singlet fission demonstrate the numerical accuracy and practical utility of this approach.
Increased mobility for layer-by-layer transferred chemical vapor deposited graphene/boron-nitride thin films
Authors: Nayfeh Osama M. , Glen Birdwell A. , Tan Cheng , Dubey Madan , Gullapalli Hemtej , Liu Zheng , Leela Mohana Reddy Arava , Ajayan Pulickel M.
Published: March 2013

Large-area chemical vapor deposited graphene/boron-nitride (G/BN) thin films are co-transferred layer-by-layer to silicon-di-Oxide (SiO2) substrates, and transistors are constructed and examined. Raman spectra and high resolution transmission electron microscopy imaging show films of high quality. The graphene/boron-nitride/SiO2 devices have a significantly increased peak electron/hole mobility of 3400/2200 cm2/Vs with a reduced effective doping density over reference graphene/SiO2 devices. The mobility dependence as a function of carrier density is compared with a physically based empirical model and is in agreement with the improvements due to a consistent reduction in the substrate induced phonon and impurity scattering and an improvement in the overall surface quality owed to the boron-nitride interlayer that separates the graphene from the SiO2. Large-area G/BN thin films are promising for future high performance thin film electronic devices.
Smoothing metallic glasses without introducing crystallization by gas cluster ion beam
Authors: Shao Lin , Chen Di , Myers Michael , Wang Jing , Tilakaratne Buddhi , Wijesundera Dharshana , Chu Wei-Kan , Xie Guoqiang , Zare Arezoo , Lucca Don A.
Published: March 2013

We show that 30 keV Ar cluster ion bombardment of Ni52.5Nb10Zr15Ti15Pt7.5 metallic glass (MG) can remove surface mountain-like features and reduce the root mean square surface roughness from 12 nm to 0.7 nm. X-ray diffraction analysis reveals no crystallization after cluster ion irradiation. Molecular dynamics simulations show that, although damage cascades lead to local melting, the subsequent quenching rate is a few orders of magnitude higher than the critical cooling rate for MG formation, thus the melted zone retains its amorphous nature down to room temperature. These findings can be applied to obtain ultra-smooth MGs without introducing crystallization.
On the equivalence between specific adsorption and kinetic equation descriptions of the admittance response in electrolytic cells
Authors: Evangelista Luiz Roberto , Lenzi Ervin Kaminski , Barbero Giovanni , Macdonald James Ross
Published: March 2013

The response of an electrolytic cell, in the shape of a slab, is analyzed in the framework of the Poisson-Nernst-Planck model in the limit of full dissociation. Two different types of boundary conditions on the electrodes are compared. One type describes the exchange of charges between the volume and the external circuit, in the form originally proposed by Chang and Jaffé and later extended to include specific adsorption, where the surface current density is proportional to the variation of the surface bulk density of ions with respect to the value of equilibrium. The other one describes the surface adsorption, in the limit of Langmuir. We show that in the simple case where the ions dissolved in the insulating liquid are identical in all the aspects, except for the sign of the charge, the two models are equivalent only if the phenomenological parameter entering the boundary condition of the Chang-Jaffé model, κ, is frequency dependent, and related to the adsorption coefficient, ka, in the form κ = iωτ/(1 + iωτ) ka, where τ is the desorption time and ω the circular frequency of the applied voltage, as proposed long ago by Macdonald.
Fractional diffusion-reaction stochastic simulations
Authors: Bayati Basil S.
Published: March 2013

A novel method is presented for the simulation of a discrete state space, continuous time Markov process subject to fractional diffusion. The method is based on Lie-Trotter operator splitting of the diffusion and reaction terms in the master equation. The diffusion term follows a multinomial distribution governed by a kernel that is the discretized solution of the fractional diffusion equation. The algorithm is validated and simulations are provided for the Fisher-KPP wavefront. It is shown that the wave speed is dictated by the order of the fractional derivative, where lower values result in a faster wave than in the case of classical diffusion. Since many physical processes deviate from classical diffusion, fractional diffusion methods are necessary for accurate simulations.
Comment on “Undamped electrostatic plasma waves” [Phys. Plasmas 19, 092103 (2012)]
Authors: Schamel Hans
Published: March 2013

The relevance of linear “corner modes” for the description of coherent electrostatic structures, as proposed by Valentini et al. [Phys. Plasmas 19, 092103 (2012)], is questioned. Coherency in their on-dispersion simulation is instead found to be caused by particle trapping in agreement with Schamel's nonlinear wave model [Phys. Plasmas 19, 020501 (2012)]. The revealed small amplitude structures are hence of cnoidal electron hole type exhibiting vortices in phase space. They are ruled by trapping nonlinearity rather than by linearity or quasi-linear effects, as commonly assumed. Arguments are presented, which give preference to these cnoidal hole modes over Bernstein-Greene-Kruskal modes. To fully account for a realistic theoretical scenario, however, at least four ingredients are mandatory. Several corrections of the conventional body of thought about the proper kinetic wave description are proposed. They may prove useful for the general acceptance of this “new” nonlinear wave concept concerning structure formation, updating several prevailing concepts such as the general validity of a linear wave Ansatz for small amplitudes, as assumed in their paper. It is conjectured that this nonlinear trapping model can be generalized to the vortex structures of similar type found in the more general setting of driven turbulence of magnetized plasmas. They appear as eddies in both, the phase and the position spaces, embedded intermittently on the Debye length scale.
Response to “Comment on ‘Undamped electrostatic plasma waves’” [Phys. Plasmas 20, 034701 (2013)]
Authors: Valentini F. , Perrone D. , Califano F. , Pegoraro F. , Veltri P. , Morrison P. J. , O'Neil T. M.
Published: March 2013

Numerical and experimental evidence is given for the occurrence of the plateau states and concomitant corner modes proposed in Valentini et al. [Phys. Plasmas 19, 092103 (2012)]. It is argued that these states provide a better description of reality for small amplitude off-dispersion disturbances than the conventional Bernstein-Greene-Kruskal or cnoidal states such as those proposed in Schamel [Phys. Plasmas 20, 034701 (2013)].
Marcus canonical integral for non-Gaussian processes and its computation: Pathwise simulation and tau-leaping algorithm
Authors: Li Tiejun , Min Bin , Wang Zhiming
Published: March 2013

The stochastic integral ensuring the Newton-Leibnitz chain rule is essential in stochastic energetics. Marcus canonical integral has this property and can be understood as the Wong-Zakai type smoothing limit when the driving process is non-Gaussian. However, this important concept seems not well-known for physicists. In this paper, we discuss Marcus integral for non-Gaussian processes and its computation in the context of stochastic energetics. We give a comprehensive introduction to Marcus integral and compare three equivalent definitions in the literature. We introduce the exact pathwise simulation algorithm and give the error analysis. We show how to compute the thermodynamic quantities based on the pathwise simulation algorithm. We highlight the information hidden in the Marcus mapping, which plays the key role in determining thermodynamic quantities. We further propose the tau-leaping algorithm, which advance the process with deterministic time steps when tau-leaping condition is satisfied. The numerical experiments and its efficiency analysis show that it is very promising.
Order parameter free enhanced sampling of the vapor-liquid transition using the generalized replica exchange method
Authors: Lu Qing , Kim Jaegil , Straub John E.
Published: March 2013

The generalized Replica Exchange Method (gREM) is extended into the isobaric-isothermal ensemble, and applied to simulate a vapor-liquid phase transition in Lennard-Jones fluids. Merging an optimally designed generalized ensemble sampling with replica exchange, gREM is particularly well suited for the effective simulation of first-order phase transitions characterized by “backbending” in the statistical temperature. While the metastable and unstable states in the vicinity of the first-order phase transition are masked by the enthalpy gap in temperature replica exchange method simulations, they are transformed into stable states through the parameterized effective sampling weights in gREM simulations, and join vapor and liquid phases with a succession of unimodal enthalpy distributions. The enhanced sampling across metastable and unstable states is achieved without the need to identify a “good” order parameter for biased sampling. We performed gREM simulations at various pressures below and near the critical pressure to examine the change in behavior of the vapor-liquid phase transition at different pressures. We observed a crossover from the first-order phase transition at low pressure, characterized by the backbending in the statistical temperature and the “kink” in the Gibbs free energy, to a continuous second-order phase transition near the critical pressure. The controlling mechanisms of nucleation and continuous phase transition are evident and the coexistence properties and phase diagram are found in agreement with literature results.
Influence of hydrogen on interstitial iron concentration in multicrystalline silicon during annealing steps
Authors: Karzel Philipp , Frey Alexander , Fritz Susanne , Hahn Giso
Published: March 2013

The influence of in-diffusing atomic H into an annealed multicrystalline silicon (mc-Si) wafer on the concentration of interstitial iron [Fei] was investigated. Neighboring wafers with similar initial [Fei] were annealed with and without in-diffusing H. In-diffusion was realized by exposing the samples to a microwave induced remote hydrogen plasma at 400 °C. [Fei] was detected based on lifetime measurements before and after dissociating the FeB complex. Surface passivation was achieved by a quinhydrone-methanol solution at room temperature to avoid further temperature steps or in-diffusion of H during surface passivation. From [Fei] measurements before and after the annealing steps with and without H, the influence of H alone on [Fei] could be accessed. The results were compared to previous experiments where the same SiNx:H layers were used as surface passivation for multiple [Fei] measurements of mc-Si samples before and after several anneals at 400 °C. It could be shown that a H plasma atmosphere has a strong additional effect on the reduction of [Fei] compared to temperature effects alone. A formation of H-Fei complexes associated with the passivation of the electrical activity of Fei could be shown to be improbable because no depassivation of Fei could be observed in subsequent annealing steps at 400 °C.
Two-port microwave calibration at millikelvin temperatures
Authors: Ranzani Leonardo , Spietz Lafe , Popovic Zoya , Aumentado José
Published: March 2013

In this work we introduce a system for 2-port microwave calibration at millikelvin temperatures operating at the coldest stage of a dilution refrigerator by use of an adapted thru-reflect-line algorithm. We show that this can be an effective tool for characterizing common 50 Ω microwave components with better than 0.1 dB accuracy at temperatures that are relevant to many current experiments in superconducting quantum information.
Particle simulation of collision dynamics for ion beam injection into a rarefied gas
Authors: Giuliano Paul N. , Boyd Iain D.
Published: March 2013

This study details a comparison of ion beam simulations with experimental data from a simplified plasma test cell in order to study and validate numerical models and environments representative of electric propulsion devices and their plumes. The simulations employ a combination of the direct simulation Monte Carlo and particle-in-cell methods representing xenon ions and atoms as macroparticles. An anisotropic collision model is implemented for momentum exchange and charge exchange interactions between atoms and ions in order to validate the post-collision scattering behaviors of dominant collision mechanisms. Cases are simulated in which the environment is either collisionless or non-electrostatic in order to prove that the collision models are the dominant source of low- and high-angle particle scattering and current collection within this environment. Additionally, isotropic cases are run in order to show the importance of anisotropy in these collision models. An analysis of beam divergence leads to better characterization of the ion beam, a parameter that requires careful analysis. Finally, suggestions based on numerical results are made to help guide the experimental design in order to better characterize the ion environment.
Synthesis and magnetic properties of core/shell FeO/Fe3O4 nano-octopods
Authors: Khurshid Hafsa , Chandra Sayan , Li Wanfeng , Phan M. H. , Hadjipanayis G. C. , Mukherjee P. , Srikanth H.
Published: March 2013

We report the synthesis and magnetic properties of core/shell FeO/Fe3O4 nanoparticles with an average size of 30 nm in a complex quasi-octopod shape. FeO nanoparticles were synthesized by a wet chemical synthesis route followed by partial oxidation to form core/shell structured FeO/Fe3O4 octopods. X-ray diffraction and transmission electron microscopy confirmed the presence of iron oxide phases and the formed core/shell FeO/Fe3O4 morphology. Magnetic measurements revealed two distinct temperatures corresponding to the thermally activated Verwey transition (TV ∼ 120 K) of the ferrimagnetic Fe3O4 shell and the Neel temperature (TN ∼ 230 K) of the antiferromagnetic FeO core. The nanoparticles exhibited a strong horizontal shift in the field-cooled hysteresis loop (the so-called exchange bias (EB) effect) accompanied by enhanced coercivity. The Meiklejohn-Bean model has been implemented to quantify the amount of frozen spins that locate at the interface between FeO and Fe3O4 and are responsible for the observed EB effect.
Ultraviolet irradiation induced polarization restoration in electrically fatigued ferroelectric polymer films
Authors: Fu Shaosong , Yu Hao , Hu Jinghang , Ding Shijin , Cheng Qian , Jiang Yulong , Zhu Guodong
Published: March 2013

Polarization fatigue is a kind of phenomenon usually observed in most ferroelectric films, which severely degrades the electrical performance of ferroelectric devices. How to restore those degraded polarization as well as how to improve fatigue endurance has been attracting much attention. Here, we report the observation of ultraviolet (UV) irradiation induced polarization restoration in ferroelectric polymer films. Large numbers of experiments indicate that the simultaneous application of UV irradiation and DC bias voltage will result in polarization restoration, which is dependent on both electrical polarity of DC bias and the UV intensity. Repeated fatigue and restoration measurements are also conducted. Based on fatigue mechanism in ferroelectric polymer films, UV-induced restoration is discussed.
Simulations of nanosecond-pulsed dielectric barrier discharges in atmospheric pressure air
Authors: Soo Bak Moon , Cappelli Mark A.
Published: March 2013

This paper describes simulations of nanosecond pulse plasma formation between planer electrodes covered by dielectric barriers in air at atmospheric pressure and 340 K. The plasma formation process starts as electrons detach from negative ions of molecular oxygen that are produced from the previous discharge pulse. An ionization front is found to form close to the positively biased electrode and then strengthens and propagates towards the grounded electrode with increasing gap voltage. Charge accumulation and secondary emission from the grounded electrode eventually lead to sheath collapse. One interesting feature is a predicted reversal in gap potential due to the accumulated charge, even when there is no reversal in applied potential. The simulation results are compared to recent measurement of mid-gap electric field under the same discharge conditions [Ito et al., Phys. Rev. Lett. 107, 065002 (2011)].
Modeling the motion and detection of particles in microcantilever sensor cells
Authors: Manning K. Y. , Butt N. R. , Alodhayb Abdullah , Saika-Voivod I. , Beaulieu L. Y.
Published: March 2013

Consideration of the dynamics of the liquid is often neglected in experiments carried out in flow-through microcantilever sensor cells. Thus, fluid dynamics simulations were performed showing that the geometry of the sensor cell and laminar nature of the flow may result in a highly uneven distribution of particulates throughout the cell, and hence an uneven detection rate at individual cantilevers in a multi-lever setup. Various strategies for diverting flow were tested in order to optimize particle capture rates. Additionally, DNA detection experiments were performed that validated our approximations in treating particle-cantilever interactions and provided a semi-quantitative relationship between simulated particle detection and actual cantilever deflections. The results point out the advantages of flow optimization, the need for calibration of individual cantilevers within a multi-lever cell, and the usefulness of simulation in achieving these goals.
Curvature aided long range propagation of short laser pulses in the atmosphere
Authors: Yedierler Burak
Published: March 2013

The pre-filamentation regime of propagation of a short and intense laser pulse in the atmosphere is considered. Spatiotemporal self-focusing dynamics of the laser beam are investigated by calculating the coupled differential equations for spot size, pulse length, phase, curvature, and chirp functions of a Gaussian laser pulse via a variational technique. The effect of initial curvature parameter on the propagation of the laser pulse is taken into consideration. A method relying on the adjustment of the initial curvature parameter can expand the filamentation distance of a laser beam of given power and chirp is proposed.
Two-dimensional energy transfer between self-assembled quantum dots modulated by an external electric field
Authors: Marques F. A. M. , Monte A. F. G.
Published: March 2013

Energy transfer processes between InAs/GaAs self-assembled quantum dots within an intrinsic region of a p-i-n device have been studied. Three emission peaks associated with quantum dots (QDs) energy states could be identified in the photoluminescence (PL) spectrum in such a way that the energy transfer between lateral QDs could be individualized for each state. Using the spatially resolved micro-PL technique, several scans have been performed in the whole range of QDs emissions at different values of direct applied bias Vb. Curves were fitted according to the diffusion theory, and the parameters associated with the energy transfer (L) were plotted as a function of Vb and the QD recombination energy. We found that the energy transfer between QDs is faster for lower energy states and increases, with different rates, for each QD energy state by increasing the direct applied bias. The energy transfer process has been associated with the carrier diffusion within the barriers. We also found that the energy transfer between QDs decreases linearly with the electron-hole recombination energy. From this result, we conclude that the energy transfer phenomenon occurs following a Gaussian distribution of diffusing carriers, in which the concentrations of electron-hole pairs far away from the origin are just enough to fill the lower energy states of QDs.
Physical properties of Cu2ZnSnS4 thin films deposited by spray pyrolysis technique
Authors: Seboui Zeineb , Cuminal Yvan , Kamoun-Turki Najoua
Published: March 2013

Thin films of Cu2ZnSnS4 (CZTS) were deposited on Pyrex substrates at various temperatures by spray pyrolysis technique from aqueous solution containing an economic stannous chloride (SnCl2) precursor for the tin and the effect of substrate temperature on the structural and opto-electronic properties was investigated. X-ray diffraction patterns and Raman spectroscopy reveal that all the CZTS films exhibited kesterite structure with preferential orientation along the (1 1 2) direction and some secondary phases. Also, they possessed different band gaps, which were found to lie between 1.52 and 1.81 eV, indicating that CZTS compound has absorbing properties favorable for applications in solar cell devices. Van der Pauw technique and Hall effect measurements were used to determine the electrical properties of CZTS films and the resistivity was of about 0.12 Ω cm for film grown at 280 °C.