bluuebunny/crossref_metadata_2025 huggingface dataset:
‘Gratuitous Assistance’? The West End Theatre Industry, Late Victorian Charity, and Patterns of Theatrical Fundraising
Authors: Hindson Catherine
Published: February 2014

London's theatre industry and charity culture have been closely connected since the mid-nineteenth century. In this article Catherine Hindson explores the nature of this relationship in the later years of the century. Focusing on a charity bazaar held at the Royal Albert Hall in June 1899 to raise funds for the Charing Cross Hospital, she argues that extra-theatrical occasions staged for charity organizations were firmly located within the stage culture of the day. Rather than peripheral occasions, high-profile, public charity events functioned as significant forces in the reputation and success of the West End theatre industry and its personnel. They held cultural, social, and economic potential for theatrical performers and represent a key factor in the improvement in the moral and social status of the stage in this period. Catherine Hindson is Senior Lecturer in Theatre and Performance Studies at the University of Bristol. She has published widely on popular performance between 1820 and 1930 and is currently completing a monograph on the actress, the West End stage, and charity between 1880 and 1930.
Karolos Koun in the 1930s and the Birth of Modernist Shakespeare in Greece
Authors: Glytzouris Antonis
Published: February 2014

The author aims in this article is to highlight a significant moment in the history of the reception of Shakespeare in modern Greek theatre. The article outlines the main developments in the perception of Shakespeare's work in Greece from the mid-nineteenth century until the Second World War, and examines Karolos Koun's early experiments in Shakespearean production. Koun's initiatives were diametrically opposed to local theatre traditions, which emphasized psychological or historical realism and pictorial or spectacular illusion. The use of non-realistic stage conventions such as masks and simple, abstract and allusive settings, flamboyant costumes, stylized acting, and the fact that all roles were played by young boys demonstrate the significance of Koun's contribution to a modernist Shakespeare in Greece, culminating in his Romeo and Juliet with the Royal Shakespeare Company at Stratford in 1967. Antonis Glytzouris is Associate Professor in the School of Drama at the Aristotle University Thessaloniki, and is author of Stage Direction in Greece: the Rise and Consolidation of the Stage Director in Modern Greek Theatre (Herakleio: Crete University Press, 2011), among other publications.
Activity pattern of the neotropical marsupialDidelphis auritain south-eastern Brazilian Atlantic Forest
Authors: Ferreira Mariana Silva , Vieira Marcus Vinícius
Published: February 2014

Nocturnal activity is generally presumed, but rarely evaluated in studies of tropical small mammals. When evaluated, activity is frequently presented as a fixed pattern, but actually it is the influence of biotic and abiotic factors on individuals. We investigated effects of age, sex, minimum temperature, reproductive and climatic seasons on activity ofDidelphis aurita(Didelphimorphia, Didelphidae) in an Atlantic Forest area in south-eastern Brazil from June 2009 to December 2010. We captured 37 individuals, 51 times (28 females and 23 males). Activity ofD. auritawas mostly nocturnal, but some individuals were active during the day (12%, N = 6). Nocturnal activity was bimodal, more prevalent in adults than juveniles, and different from most neotropical marsupials. Contrary to expectations, individuals ofD. auritawere more active at colder temperatures, which indicates that low temperatures do not limit foraging behaviour.
Probability increment based swarm optimization for combinatorial optimization with application to printed circuit board assembly
Authors: Zeng Kehan , Tan Zhen , Dong Mingchui , Yang Ping
Published: February 2014

A novel swarm intelligence approach for combinatorial optimization is proposed, which we call probability increment based swarm optimization (PIBSO). The population evolution mechanism of PIBSO is depicted. Each state in search space has a probability to be chosen. The rule of increasing the probabilities of states is established. Incremental factor is proposed to update probability of a state, and its value is determined by the fitness of the state. It lets the states with better fitness have higher probabilities. Usual roulette wheel selection is employed to select states. Population evolution is impelled by roulette wheel selection and state probability updating. The most distinctive feature of PIBSO is because roulette wheel selection and probability updating produce a trade-off between global and local search; when PIBSO is applied to solve the printed circuit board assembly optimization problem (PCBAOP), it performs superiorly over existing genetic algorithm and adaptive particle swarm optimization on length of tour and CPU running time, respectively. The reason for having such advantages is analyzed in detail. The success of PCBAOP application verifies the effectiveness and efficiency of PIBSO and shows that it is a good method for combinatorial optimization in engineering.
Transport of Intensity Phase Reconstruction Revisited
Authors: Lubk A. , Guzzinati G. , Clark L. , Verbeeck J.
Published: February 2014

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.
Kritische Debatte zur Generalistischen Pflegeausbildung
Authors: Sahmel Karl-Heinz
Published: February 2014

Das „Eckpunktepapier zur Vorbereitung eines Entwurfes eines neuen Pflegeberufegesetzes“ soll ein Gesamtkonzept darstellen und zugleich wesentliche Aspekte eines neuen Gesetzes aufweisen. Über grundlegende Aspekte der Qualifikation in der Pflege sollte auch weiterhin ergebnisoffen diskutiert werden.
Lebenslanges Lernen in der Pflege
Authors: Haselhorst Alexander
Published: February 2014

Lehr-Lern-Arrangements können Selbstlernkompetenzen bereits in der Pflegeausbildung fördern, die in den Pflegeweiterbildungen vertieft werden können. In diesem Beitrage soll geklärt werden, inwieweit Lehr-Lern-Arrangements im Rahmen der Aus- und Weiterbildung von Pflegekräften ein Lebenslanges Lernen ermöglichen können. Es werden sowohl die zum Lebenslangen Lernen erforderlichen Kompetenzen beschrieben, als auch die Unterrichts- und Sozialformen dargestellt, mit denen Selbstlernkompetenzen gefördert werden können.
Quantitative Tissue Ph Measurement during Cerebral Ischemia Using Amine and Amide Concentration-Independent Detection (AACID) with MRI
Authors: McVicar Nevin , Li Alex X , Gonçalves Daniela F , Bellyou Miranda , Meakin Susan O , Prado Marco AM , Bartha Robert
Published: February 2014

Tissue pH is an indicator of altered cellular metabolism in diseases including stroke and cancer. Ischemic tissue often becomes acidic due to increased anaerobic respiration leading to irreversible cellular damage. Chemical exchange saturation transfer (CEST) effects can be used to generate pH-weighted magnetic resonance imaging (MRI) contrast, which has been used to delineate the ischemic penumbra after ischemic stroke. In the current study, a novel MRI ratiometric technique is presented to measure absolute pH using the ratio of CEST-mediated contrast from amine and amide protons: amine/amide concentration-independent detection (AACID). Effects of CEST were observed at 2.75 parts per million (p.p.m.) for amine protons and at 3.50 p.p.m. for amide protons downfield (i.e., higher frequency) from bulk water. Using numerical simulations and in vitro MRI experiments, we showed that pH measured using AACID was independent of tissue relaxation time constants, macromolecular magnetization transfer effects, protein concentration, and temperature within the physiologic range. After in vivo pH calibration using phosphorus (31P) magnetic resonance spectroscopy (31P-MRS), local acidosis is detected in mouse brain after focal permanent middle cerebral artery occlusion. In summary, our results suggest that AACID represents a noninvasive method to directly measure the spatial distribution of absolute pH in vivo using CEST MRI.
Unconventional upright layer orientation and considerable enhancement of proton–electron conductivity in Dion–Jacobson perovskite thin films
Authors: Nakajima Tomohiko , Kobayashi Kiyoshi , Shinoda Kentaro , Tsuchiya Tetsuo
Published: February 2014

Excimer-laser-assisted metal organic deposition is a straightforward process for growing uniaxially oriented Dion–Jacobson perovskite thin films.
Three-dimensional nano-biointerface as a new platform for guiding cell fate
Authors: Liu Xueli , Wang Shutao
Published: February 2014

The recent explorations of three-dimensional nano-biointerfaces for cell-related fundamental biological studies and advanced biomedical applications are reviewed.
Electrochemical mineral scale prevention and removal on electrically conducting carbon nanotube – polyamide reverse osmosis membranes
Authors: Duan Wenyan , Dudchenko Alexander , Mende Elizabeth , Flyer Celeste , Zhu Xiaobo , Jassby David
Published: February 2014

Electrically charged carbon nanotube composite reverse osmosis membranes have been demonstrated to prevent CaSO4 scaling during brackish water desalination.
Application of a three-dimensional (3D) particle tracking method to microfluidic particle focusing
Authors: Winer Michael H. , Ahmadi Ali , Cheung Karen C.
Published: February 2014

This work represents the first implementation of a defocusing-based three-dimensional (3D) particle tracking technique for microfluidic particle focusing applications.
Microfluidic spinning of micro- and nano-scale fibers for tissue engineering
Authors: Jun Yesl , Kang Edward , Chae Sukyoung , Lee Sang-Hoon
Published: February 2014

Microfluidic-based spinning techniques for producing micro- and nano-scale fibers, and their potential applications to tissue engineering are reviewed.
Efficient visible light-mediated cross-dehydrogenative coupling reactions of tertiary amines catalyzed by a polymer-immobilized iridium-based photocatalyst
Authors: Yoo Woo-Jin , Kobayashi Shū
Published: February 2014

A polymer-supported Ir-based visible light photocatalyst was developed, and was evaluated as a heterogeneous catalyst for the aerobic phosphonylation reaction ofN-aryl tetrahydroisoquinolines.
More than just a GPCR ligand: structure-based discovery of thioridazine derivatives as Pim-1 kinase inhibitors
Authors: Li Wei , Wan Xiaobo , Zeng Fanqi , Xie Yuting , Wang Yanli , Zhang Wei , Li Li , Huang Niu
Published: February 2014

A structure-based hierarchical virtual screening method was employed to identify a GPCR ligand, thioridazine, as a Pim-1 kinase inhibitor.
Redox sulfur chemistry of the copper chaperone Atox1 is regulated by the enzyme glutaredoxin 1, the reduction potential of the glutathione couple GSSG/2GSH and the availability of Cu(i)
Authors: Brose Jens , La Fontaine Sharon , Wedd Anthony G. , Xiao Zhiguang
Published: February 2014

Grx1 binds Cu(i) with femtomolar affinity and catalyses reversible redox sulfur chemistry of Atox1 with direction regulated by the cell potential and Cu(i) availability.
Molecular design for a cybotactic nematic phase
Authors: Nishiya Wataru , Takanishi Yoichi , Yamamoto Jun , Yoshizawa Atsushi
Published: February 2014

We propose two molecular designs for a cybotactic nematic (Ncyb) phase. The U-shaped compound exhibits a skewed Ncyb phase, whereas the rod-like compound possessing a terminal hydroxyl group shows a normal Ncyb phase.
GLCE regulates PC12 cell neuritogenesis induced by nerve growth factor through activating SMAD/ID3 signalling
Authors: Li Jie , Fang Jianping , Qin Yi , Liao Wenfeng , Liu Hailing , Zhou Yifa , Ding Kan
Published: February 2014

Neurodevelopment is orchestrated by a series of growth factor–HS (heparan sulfate) interactions which are involved in neuritogenesis. GLCE (glucuronic acid epimerase) is a critical enzyme involved in HS synthesis, which converts GlcA (D-glucuronic acid) into IdoA (L-iduronic acid). However, the function of GLCE in neuritogenesis is largely unknown. In the present study we showed that GLCE depletion caused arrested PC12 cell growth and promoted the cell neuritogenesis and differentiation induced by NGF (nerve growth factor). PC12 cell growth was boosted by overexpression of GLCE, and neuritogenesis was impaired when GLCE depletion was rescued. Interestingly, overexpression of wild-type GLCE with Y168A and Y222A mutations led to enhanced PC12 cell growth and attenuated the neuritogenesis triggered by GLCE silencing. We showed further that GLCE depletion blocked SMAD1/5/8 phosphorylation; however, this signalling could be restored by GLCE or the mutation of its active enzymatic site. In addition, the downstream effector of SMAD1/5/8, ID3 (inhibitor of DNA binding/differentiation 3) was induced by GLCE. ID3 silencing inhibited PC12 cell growth and induced cell neuritogenesis and differentiation. In addition, ectopic expression of ID3 partially rescued the phenotype caused by GLCE silencing. The results of the present study suggest that GLCE plays a key role in PC12 cell growth and neuritogenesis through SMAD/ID3 signalling.
A Sociolinguistic Investigation of the Speech of African American Preschoolers
Authors: Bleile Ken M. , Wallach Hillary
Published: February 2014

In this study we attempted to investigate aspects of the sociolinguistic environment of African American preschoolers. Specifically, preschool teachers were asked to identify African American preschoolers who "have trouble speaking." Subsequently, speech-language pathologists analyzed samples of the children’s speech to isolate the speech patterns that may have corresponded to the teacher’s judgments. Subjects included 27 children who were enrolled in an inner city Head Start program. Head Start teachers belonging to the same race and community as the children acted as judges. The analysis yielded a number of speech patterns that distinguished the children judged to have trouble speaking from children judged to have no difficulties in speaking.
Semi-Structured Listening Experience (Listening Training) in Hearing Aid Fitting: Influence on Dichotic Listening
Authors: Lavie Limor , Attias Joseph , Karni Avi
Published: February 2014

Purpose

In this study, the authors tested whether training with amplified, clear speech in regular room acoustics would result in larger perceptual gains of auditory processing in elderly hearing aid users.

Method

Elderly participants with hearing impairment (N= 36, ages 64–88) were fitted with bilateral hearing aids and were randomly assigned to 2 unequal groups. Study group participants were provided with 7 sessions (1 month) of individual listening training during which a free conversation was conducted, with the aim of stimulating the amplified ears with verbal auditory input. The control group participants were fitted with hearing aids without training. Auditory processing changes were assessed through the use of dichotic listening tasks.

Results

During hearing aid use, dichotic listening scores—tested without the hearing aids—improved in both groups, mainly in the non-dominant ears. The overall dichotic performance was significantly higher in the study group, and the main effect of auditory training was manifested in the scores of the dominant ear.

Conclusions

Hearing aid use may improve auditory processing performance as tested in unaided conditions. Listening training has an additional beneficial effect on the dominant ear—that is, the ear with the lesser potential for improvement. Listening training in elderly adults presumably enhanced the acclimatization process by better recruiting the potential for auditory plasticity and improving attention recruitment.
The Diagnostic Accuracy of Two Tense Measures for Identifying 3-Year-Olds With Language Impairment
Authors: Guo Ling-Yu , Eisenberg Sarita
Published: February 2014

Purpose

The authors of this study investigated the diagnostic accuracy of the Finite Verb Morphology Composite (FVMC; Bedore & Leonard, 1998) and the Tense and Agreement Productivity Score (TAPS; Hadley & Short, 2005) in identifying 3-year-olds with language impairment (LI).

Method

Eighteen pairs of 3-year-olds with and without LI participated in the current study. The FVMC and the TAPS were computed from 100- and 50-utterance language samples.

Results

The FVMC and TAPS demonstrated higher diagnostic accuracy in the 100-utterance samples than in the 50-utterance samples. For 100-utterance samples, when children's age or severity was not considered, the FVMC showed a slight advantage over the TAPS in diagnostic accuracy. However, when children's age or severity was considered, the opposite pattern was observed.

Conclusion

Both the FVMC and TAPS can be used to differentiate 3-year-olds with and without LI. To reliably identify 3-year-olds with LI by using tense measures, language samples with at least 100 utterances are recommended.
Potential energy surface fitting by a statistically localized, permutationally invariant, local interpolating moving least squares method for the many-body potential: Method and application to N4
Authors: Bender Jason D. , Doraiswamy Sriram , Truhlar Donald G. , Candler Graham V.
Published: February 2014

Fitting potential energy surfaces to analytic forms is an important first step for efficient molecular dynamics simulations. Here, we present an improved version of the local interpolating moving least squares method (L-IMLS) for such fitting. Our method has three key improvements. First, pairwise interactions are modeled separately from many-body interactions. Second, permutational invariance is incorporated in the basis functions, using permutationally invariant polynomials in Morse variables, and in the weight functions. Third, computational cost is reduced by statistical localization, in which we statistically correlate the cutoff radius with data point density. We motivate our discussion in this paper with a review of global and local least-squares-based fitting methods in one dimension. Then, we develop our method in six dimensions, and we note that it allows the analytic evaluation of gradients, a feature that is important for molecular dynamics. The approach, which we call statistically localized, permutationally invariant, local interpolating moving least squares fitting of the many-body potential (SL-PI-L-IMLS-MP, or, more simply, L-IMLS-G2), is used to fit a potential energy surface to an electronic structure dataset for N4. We discuss its performance on the dataset and give directions for further research, including applications to trajectory calculations.
Misfit strain driven cation inter-diffusion across an epitaxial multiferroic thin film interface
Authors: Sankara Rama Krishnan P. S. , Morozovska Anna N. , Eliseev Eugene A. , Ramasse Quentin M. , Kepaptsoglou Demie , Liang Wen-I. , Chu Ying-Hao , Munroe Paul , Nagarajan V.
Published: February 2014

Cation intermixing at functional oxide interfaces remains a highly controversial area directly relevant to interface-driven nanoelectronic device properties. Here, we systematically explore the cation intermixing in epitaxial (001) oriented multiferroic bismuth ferrite (BFO) grown on a (001) lanthanum aluminate (LAO) substrate. Aberration corrected dedicated scanning transmission electron microscopy and electron energy loss spectroscopy reveal that the interface is not chemically sharp, but with an intermixing of ∼2 nm. The driving force for this process is identified as misfit-driven elastic strain. Landau-Ginzburg-Devonshire-based phenomenological theory was combined with the Sheldon and Shenoy formula in order to understand the influence of boundary conditions and depolarizing fields arising from misfit strain between the LAO substrate and BFO film. The theory predicts the presence of a strong potential gradient at the interface, which decays on moving into the bulk of the film. This potential gradient is significant enough to drive the cation migration across the interface, thereby mitigating the misfit strain. Our results offer new insights on how chemical roughening at oxide interfaces can be effective in stabilizing the structural integrity of the interface without the need for misfit dislocations. These findings offer a general formalism for understanding cation intermixing at highly strained oxide interfaces that are used in nanoelectronic devices.
Thermoelectric transport in indium and aluminum-doped lead selenide
Authors: Evola E. G. , Nielsen M. D. , Jaworski C. M. , Jin H. , Heremans J. P.
Published: February 2014

We present galvanomagnetic and thermomagnetic properties of bulk PbSe doped by substituting the donor elements In and Al for Pb. Although prominent resonant level effects are not seen, lightly doped samples display a high thermoelectric figure of merit (zT) in excess of 1.2 at 600 K, a temperature corresponding well to automotive waste heat recovery applications. This material's high zT is achieved without the use of nanostructuring or the relatively rare element Te. Phonon drag contributions to thermopower appear at temperatures below 30 K in Al-doped samples.
Melting processes of oligomeric α and β isotactic polypropylene crystals at ultrafast heating rates
Authors: Ji Xiaojing , He Xuehao , Jiang Shichun
Published: February 2014

The melting behaviors of α (stable) and β (metastable) isotactic polypropylene (iPP) crystals at ultrafast heating rates are simulated with atomistic molecular dynamics method. Quantitative information about the melting processes of α- and β-iPP crystals at atomistic level is achieved. The result shows that the melting process starts from the interfaces of lamellar crystal through random dislocation of iPP chains along the perpendicular direction of lamellar crystal structure. In the melting process, the lamellar crystal gradually expands but the corresponding thickness decreases. The analysis shows that the system expansion lags behind the crystallinity decreasing and the lagging extents for α- and β-iPP are significantly different. The apparent melting points of α- and β-iPP crystals rise with the increase of the heating rate and lamellar crystal thickness. The apparent melting point of α-iPP crystal is always higher than that of β-iPP at differently heating rates. Applying the Gibbs-Thomson rule and the scaling property of the melting kinetics, the equilibrium melting points of perfect α- and β-iPP crystals are finally predicted and it shows a good agreement with experimental result.
Integrated fiducial sample mount and software for correlated microscopy
Authors: McJunkin Timothy R. , Trowbridge Tammy L. , Wright Karen E. , Scott Jill R.
Published: February 2014

A novel sample mount design with integrated fiducial marks and software for assisting operators in easily and efficiently locating points of interest established in previous analytical sessions is described. The sample holder and software were evaluated with experiments to demonstrate the utility and ease of finding the same points of interest in two different microscopy instruments. Also, numerical analysis of expected errors in determining the same position with errors unbiased by a human operator was performed. Based on the results, issues related to acquiring reproducibility and best practices for using the sample mount and software were identified. Overall, the sample mount methodology allows data to be efficiently and easily collected on different instruments for the same sample location.
Large-eddy simulation of offshore wind farm
Authors: Yang Di , Meneveau Charles , Shen Lian
Published: February 2014

A hybrid numerical capability is developed for the simulation of offshore wind farms, in which large-eddy simulation is performed for the wind turbulence, and a potential flow based method is used for the simulation of the ocean wave field. The wind and wave simulations are dynamically coupled. The effect of wind turbines on the wind field is represented by an actuator disk model. This study focuses on the effect of wind-seas, and the turbine motion is treated as negligibly small. A variety of fully-developed and fetch-limited wind-sea conditions and turbine spacings are considered in the study. Statistical analyses are performed for the simulation results, with a focus on the mean wind profile, kinetic energy budget in the wind field, and the wind turbine power extraction rate. The results indicate that the waves have appreciable effect on the wind farm performance. The wind turbines obtain a higher wind power extraction rate under the fully developed wind-sea condition compared with that under the fetch-limited condition. This higher extraction rate is caused by the faster propagating waves and the lower sea-surface resistance on the wind when the wind-seas are fully developed. The wave-induced difference can be as high as 8% with the commonly used turbine spacing in commercial land-based wind farms, sx = 7 (with sx being the ratio of streamwise turbine spacing to the turbine diameter). Such level of difference is noteworthy considering the previous understanding that direct wave-induced disturbance to the wind field decays exponentially away from wave surface.
Coloration and oxygen vacancies in wide band gap oxide semiconductors: Absorption at metallic nanoparticles induced by vacancy clustering—A case study on indium oxide
Authors: Albrecht M. , Schewski R. , Irmscher K. , Galazka Z. , Markurt T. , Naumann M. , Schulz T. , Uecker R. , Fornari R. , Meuret S. , Kociak M.
Published: February 2014

In this paper, we show by optical and electron microscopy based investigations that vacancies in oxides may cluster and form metallic nanoparticles that induce coloration by extinction of visible light. Optical extinction in this case is caused by generation of localized surface plasmon resonances at metallic particles embedded in the dielectric matrix. Based on Mie's approach, we are able to fit the absorption due to indium nanoparticles in In2O3 to our absorption measurements. The experimentally found particle distribution is in excellent agreement with the one obtained from fitting by Mie theory. Indium particles are formed by precipitation of oxygen vacancies. From basic thermodynamic consideration and assuming theoretically calculated activation energies for vacancy formation and migration, we find that the majority of oxygen vacancies form just below the melting point. Since they are ionized at this temperature they are Coulomb repulsive. Upon cooling, a high supersaturation of oxygen vacancies forms in the crystal that precipitates once the Fermi level crosses the transition energy level from the charged to the neutral charge state. From our considerations we find that the ionization energy of the oxygen vacancy must be higher than 200 meV.
Practical and fast quantum random number generation based on photon arrival time relative to external reference
Authors: Nie You-Qi , Zhang Hong-Fei , Zhang Zhen , Wang Jian , Ma Xiongfeng , Zhang Jun , Pan Jian-Wei
Published: February 2014

We present a practical high-speed quantum random number generator, where the timing of single-photon detection relative to an external time reference is measured as the raw data. The bias of the raw data can be substantially reduced compared with the previous realizations. The raw random bit rate of our generator can reach 109 Mbps. We develop a model for the generator and evaluate the min-entropy of the raw data. Toeplitz matrix hashing is applied for randomness extraction, after which the final random bits are able to pass the standard randomness tests.
Dynamics of a thermo-responsive microgel colloid near to the glass transition
Authors: Di Xiaojun , Peng Xiaoguang , McKenna Gregory B.
Published: February 2014

In a previous study, we used diffusing wave spectroscopy (DWS) to investigate the aging signatures of a thermo-sensitive colloidal glass and compared them with those of molecular glasses from the perspective of the Kovacs temperature-jump, volume recovery experiments [X. Di, K. Z. Win, G. B. McKenna, T. Narita, F. Lequeux, S. R. Pullela, and Z. Cheng, Phys. Rev. Lett. 106, 095701 (2011)]. In order to further look into the glassy behavior of colloidal systems, we have synthesized a new core/shell particle with lower temperature sensitivity and studied the aging signatures of concentrated systems, again following Kovacs’ protocol. Similar signatures of aging to those observed previously were seen in this new system. Moreover, a systematic study of the temperature dependence of the dynamics of the new system for different weight concentrations was performed and the dynamic fragility index m was determined. We have also explored the use of the properties determined from the DWS measurements to obtain macroscopic rheological parameters – storage modulus G′(ω) and loss modulus G″(ω) – using a generalized Stokes-Einstein approach. The micro-rheological and macro-rheological values are in reasonable agreement.
Two-dimensional percolation phenomena of single-component linear homopolymer brushes
Authors: Norizoe Yuki , Jinnai Hiroshi , Takahara Atsushi
Published: February 2014

Percolation phenomena of homopolymer brushes on a planar substrate are simulated using the molecular Monte Carlo method in 3 dimensions. The grafted polymers are isolated from each other at extremely low grafting density, whereas a continuous polymer layer covers the whole substrate when the density rises to extremely high values. This indicates that percolation clusters of the grafted polymers, bridging both the edges of the substrate, appear at an intermediate density. We construct phase diagrams of this percolation phenomenon. Critical phenomena at the transition are also studied.
Ab initio density matrix renormalization group study of magnetic coupling in dinuclear iron and chromium complexes
Authors: Harris Travis V. , Kurashige Yuki , Yanai Takeshi , Morokuma Keiji
Published: February 2014

The applicability of ab initio multireference wavefunction-based methods to the study of magnetic complexes has been restricted by the quickly rising active-space requirements of oligonuclear systems and dinuclear complexes with S > 1 spin centers. Ab initio density matrix renormalization group (DMRG) methods built upon an efficient parameterization of the correlation network enable the use of much larger active spaces, and therefore may offer a way forward. Here, we apply DMRG-CASSCF to the dinuclear complexes [Fe2OCl6]2− and [Cr2O(NH3)10]4+. After developing the methodology through systematic basis set and DMRG M testing, we explore the effects of extended active spaces that are beyond the limit of conventional methods. We find that DMRG-CASSCF with active spaces including the metal d orbitals, occupied bridging-ligand orbitals, and their virtual double shells already capture a major portion of the dynamic correlation effects, accurately reproducing the experimental magnetic coupling constant (J) of [Fe2OCl6]2− with (16e,26o), and considerably improving the smaller active space results for [Cr2O(NH3)10]4+ with (12e,32o). For comparison, we perform conventional MRCI+Q calculations and find the J values to be consistent with those from DMRG-CASSCF. In contrast to previous studies, the higher spin states of the two systems show similar deviations from the Heisenberg spectrum, regardless of the computational method.
Theory of open quantum systems with bath of electrons and phonons and spins: Many-dissipaton density matrixes approach
Authors: Yan YiJing
Published: February 2014

This work establishes a strongly correlated system-and-bath dynamics theory, the many-dissipaton density operators formalism. It puts forward a quasi-particle picture for environmental influences. This picture unifies the physical descriptions and algebraic treatments on three distinct classes of quantum environments, electron bath, phonon bath, and two-level spin or exciton bath, as their participating in quantum dissipation processes. Dynamical variables for theoretical description are no longer just the reduced density matrix for system, but remarkably also those for quasi-particles of bath. The present theoretical formalism offers efficient and accurate means for the study of steady-state (nonequilibrium and equilibrium) and real-time dynamical properties of both systems and hybridizing environments. It further provides universal evaluations, exact in principle, on various correlation functions, including even those of environmental degrees of freedom in coupling with systems. Induced environmental dynamics could be reflected directly in experimentally measurable quantities, such as Fano resonances and quantum transport current shot noise statistics.
Conical intersection seam and bound resonances embedded in continuum observed in the photodissociation of thioanisole-d3
Authors: Han Songhee , Lim Jeong Sik , Yoon Jun-Ho , Lee Jeongmook , Kim So-Yeon , Kim Sang Kyu
Published: February 2014

Herein, the multi-dimensional nature of the conical intersection seam has been experimentally revealed in the photodissociation reaction of thioanisole-d3 (C6H5SCD3) excited on S1, giving C6H5S·(${\rm \tilde A}$Ã or ${\rm \tilde X}$X̃) +·CD3 products. The translational energy distribution of the nascent·CD3 fragment, reflecting the relative yields of the C6H5S·(${\rm \tilde A}$Ã) and C6H5S·(${\rm \tilde X}$X̃) products, was measured at each S1 vibronic band using the velocity map ion imaging technique. Direct access of the reactant flux to the conical intersection seam leads to the increase of the nonadiabatic transition probability resulting in sharp resonances in the ${\rm \tilde X/\tilde AC}_6 {\rm H}_5 {\rm S}$X̃/ÃC6H5S·product branching ratio at several distinct S1 vibronic bands. The nature of the S1 vibronic bands associated with such dynamic resonances was clarified by the mass-analyzed threshold ionization spectroscopy. The bound state embedded in continuum generated by the conical intersection is observed as a distinct dynamic resonance, revealing the nature of the nuclear motion responsible for the nonadiabatic coupling of two potential energy surfaces at the conical intersection. The multi-dimensional facets of the conical intersection seam in terms of its detailed structure and dynamic role are discussed with the aid of theoretical calculations.
A family of random walks with generalized Dirichlet steps
Authors: De Gregorio Alessandro
Published: February 2014

We analyze a class of continuous time random walks in \documentclass[12pt]{minimal}\begin{document}$\mathbb {R}^d,d\ge 2,$\end{document}Rd,d≥2, with uniformly distributed directions. The steps performed by these processes are distributed according to a generalized Dirichlet law. Given the number of changes of orientation, we provide the analytic form of the probability density function of the position \documentclass[12pt]{minimal}\begin{document}$\lbrace \underline{\bf X}_d(t),t>0\rbrace$\end{document}{X̲d(t),t>0} reached, at time t > 0, by the random motion. In particular, we analyze the case of random walks with two steps. In general, it is a hard task to obtain the explicit probability distributions for the process \documentclass[12pt]{minimal}\begin{document}$\lbrace \underline{\bf X}_d(t),t>0\rbrace$\end{document}{X̲d(t),t>0}. Nevertheless, for suitable values for the basic parameters of the generalized Dirichlet probability distribution, we are able to derive the explicit conditional density functions of \documentclass[12pt]{minimal}\begin{document}$\lbrace \underline{\bf X}_d(t),t>0\rbrace$\end{document}{X̲d(t),t>0}. Furthermore, in some cases, by exploiting the fractional Poisson process, the unconditional probability distributions of the random walk are obtained. This paper extends in a more general setting, the random walks with Dirichlet displacements introduced in some previous papers.
Microstructure evolution and magnetic properties of FeB/Pt multilayers and FeBPt composite films
Authors: Su Hao , Schwarm Samuel C. , Martens Richard L. , Gupta Subhadra
Published: February 2014

Comparisons of microstructural evolution and magnetic properties were made of a FeB12/Pt10/[FeB1.2/Pt1]15/Ta5 nm multilayered structure with a FeB12/Pt10/FeBPt33/Ta5 nm co-deposited structure. The Ta capping layer was used to protect the films from oxidation. Both these samples were sputtered in the same planetary deposition system onto thermally oxidized silicon substrates. They both represent layer-by-layer deposition, with the second type of deposition having atomically fine layers, more than an order of magnitude finer than the first type. The samples were annealed at a range of times, temperatures, and vacuum conditions. X-ray diffraction (XRD), transmission electron microscopy, and alternating gradient magnetometry were employed to characterize the structural and magnetic properties, respectively. Significant differences were observed between the two types of structures. A maximum coercivity of 8.9 kOe was seen for the atomically fine multilayer, about 10% more than that for the coarse multilayer. XRD analysis confirmed that both the coarse and fine multilayers were in the L10 phase after annealing. Our results indicate that the co-deposited film, which is really composed of atomically fine multilayers, is superior to the coarse multilayered FeB/Pt for the formation of L10-phase FePt.
Theoretical study on collision dynamics of H+ + CH4 at low energies
Authors: Gao Cong-Zhang , Wang Jing , Wang Feng , Zhang Feng-Shou
Published: February 2014

In this work we make an investigation on collision dynamics of H+ + CH4 at 30 eV by using time-dependent density functional theory coupled with molecular dynamics approach. All possible reactions are presented based on 9 incident orientations. The calculated fragment intensity is in nice agreement with experimental results. The mechanism of reaction transition for dissociation and proton exchange processes is explained by the intra-molecule energy transfer. However, the energy loss of the proton is in poor agreement with experimental results. The discrepancy is attributed to the mean-field treatment of potential surface. We also studied the dependence on initial velocity of both proton and methane. In addition, we find that for dynamical evolution a different self-interaction correction (SIC) may lead to different results, but with respect to the position of rainbow angle, average-density SIC seems to have reasonable correction.
Performance evaluation of GaN light-emitting diodes using transferred graphene as current spreading layer
Authors: Chandramohan S. , Bok Ko Kang , Han Yang Jong , Deul Ryu Beo , Katharria Y. S. , Yong Kim Taek , Jin Cho Byung , Hong Chang-Hee
Published: February 2014

This study elucidates the correlation among conductivity of graphene and interface aspects in GaN light-emitting diodes (LEDs). Using a multilayer graphene of low sheet resistance, it is demonstrated that graphene alone can make ohmic contact with p-GaN without necessitating additional interlayer. Large-area blue LED with relatively low contact resistance in the order of 10−2 ohm-cm2 and improved forward voltage of 3.2 ± 0.1 V was realized irrespective of the use of the interlayer. The results from parallel evaluation experiments performed by varying the layer numbers of graphene with ultrathin NiOx interlayer revealed that the poor lateral conductivity of monolayer or few layer graphene can be well compensated by the interlayer. A combination of three layer graphene and NiOx offered device with enhanced electro-optical performance. But the Schottky barrier associated with the inadequate adhesion of transferred graphene dominates all the benefits and becomes a major bottleneck preventing the formation of low resistance stable ohmic contact.
Frequency and amplitude modulations in crystal resonators due to transient thermal effects
Authors: Cui Jing , Du Jianke , Wang Ji , Yang Jiashi
Published: February 2014

We show through a theoretical analysis that when a crystal resonator is subjected to a transient temperature change, in addition to the known frequency shift or modulation, there always exists an accompanying amplitude modulation. The theory for small fields superposed on finite initial fields is employed and reduced to an ordinary differential equation with a time-dependent coefficient. An approximate analytical solution is obtained. The solution shows that the frequency modulation is a first-order effect, and the amplitude modulation is a second-order effect. The results are useful to the understanding and design optimization of crystal resonators.
A particle image velocimetry study of the flow physics generated by a thin lamina oscillating in a viscous fluid
Authors: Jalalisendi Mohammad , Panciroli Riccardo , Cha Youngsu , Porfiri Maurizio
Published: February 2014

In this paper, we study the flow physics produced by a thin rigid lamina oscillating in an otherwise quiescent viscous fluid. Particle image velocimetry (PIV) is used to extract the flow kinematics, which is, in turn, utilized to reconstruct the pressure distribution around the lamina through the integration of Navier-Stokes equations. The hydrodynamic loading experienced by the lamina is ultimately estimated from PIV data to investigate added mass and fluid damping phenomena. Experiments are conducted for varying Reynolds and Keulegan-Carpenter numbers to elucidate the relative weight of inertial, convective, and viscous phenomena on the resulting flow physics. In agreement with prior numerical studies, experimental results demonstrate that increasing the Reynolds and the Keulegan-Carpenter numbers results into the formation of coherent structures that are shed at the edges of the lamina and advected by the flow. This phenomenon is associated with nonlinearities in the hydrodynamic loading, whereby fluid damping is found to increase nonlinearly with the oscillation of the lamina.
Enhancing the Cu2ZnSnS4 solar cell efficiency by back contact modification: Inserting a thin TiB2 intermediate layer at Cu2ZnSnS4/Mo interface
Authors: Liu Fangyang , Sun Kaiwen , Li Wei , Yan Chang , Cui Hongtao , Jiang Liangxing , Hao Xiaojing , Green Martin A.
Published: February 2014

In this work, TiB2 thin films have been employed as intermediate layer between absorber and back contact in Cu2ZnSnS4 (CZTS) thin film solar cells for interface optimization. It is found that the TiB2 intermediate layer can significantly inhibit the formation of MoS2 layer at absorber/back contact interface region, greatly reduces the series resistance and thereby increases the device efficiency by short current density (Jsc) and fill factor boost. However, introducing TiB2 degrades the crystal quality of absorber, which is detrimental to device performance especially Voc. The careful control of the thickness of TiB2 intermediate layer is required to ensure both MoS2 with minimal thickness and CZTS absorber with large grain microstructure according to the absorber growth process.
Crucial role of implanted atoms on dynamic defect annealing in ZnO
Authors: Azarov A. Yu. , Wendler E. , Kuznetsov A. Yu. , Svensson B. G.
Published: February 2014

Processes of defect formation in radiation hard semiconductors exhibiting efficient dynamic annealing are different from those in amorphizible ones, and the latter are generally more well-studied. In the present work, we investigate structural disorder in wurtzite ZnO, which is a radiation hard material, implanted with different ions at room temperature and 15 K. The sample analysis was undertaken by Rutherford backscattering/channeling spectrometry performed in-situ without changing the sample temperature. The fluence dependence of bulk disorder exhibits the so-called IV-stage evolution, where the high fluence regime is characterized by both a strong influence on the damage build-up by the ion type and a reverse temperature effect. A straightforward methodology is demonstrated to differentiate between the contributions of pure ballistic and ion-defect reaction processes in the damage formation.
In situ measurement of CuPt alloy ordering using strain anisotropy
Authors: France Ryan M. , McMahon William E. , Kang Joongoo , Steiner Myles A. , Geisz John F.
Published: February 2014

The optical and electrical properties of many III-V alloys change with the degree of CuPt atomic ordering, which is very sensitive to growth conditions. The bulk ordered alloy is elongated along the normal to the ordered planes, and is asymmetrically strained when coherent to a cubic substrate. Here, we demonstrate in situ measurement of the anisotropic strain due to ordering using two-dimensional wafer curvature. The measurement is sensitive to bulk anisotropies, and so is complementary to other in situ measurements that are sensitive to surface anisotropies. Using ab initio calculations, we determine a maximum strain anisotropy of 0.27% between [110] and [1¯10] when perfectly ordered single-variant GaInP2 is coherent to a (001) cubic substrate. We relate the in situ measurement of strain anisotropy on various GaInP2 samples to ex situ measurements of the order parameter to validate the measurement and confirm the capability to predict material properties. The measurement monitors change in ordering during growth, useful for quickly determining the growth condition dependence of ordering or monitoring order-disorder transitions. More generally, this measurement technique could, in principle, be used to monitor phase changes in any epitaxial system for which the strain anisotropy of the two phases differs.
New route to the fabrication of nanocrystalline diamond films
Authors: Varshney Deepak , Palomino Javier , Gil Jennifer , Resto Oscar , Weiner Brad R. , Morell Gerardo
Published: February 2014

Nanocrystalline diamond (NCD) thin films offer applications in various fields, but the existing synthetic approaches are cumbersome and destructive. A major breakthrough has been achieved by our group in the direction of a non-destructive, scalable, and economic process of NCD thin-film fabrication. Here, we report a cheap precursor for the growth of nanocrystalline diamond in the form of paraffin wax. We show that NCD thin films can be fabricated on a copper support by using simple, commonplace paraffin wax under reaction conditions of Hot Filament Chemical Vapor Deposition (HFCVD). Surprisingly, even the presence of any catalyst or seeding that has been conventionally used in the state-of-the-art is not required. The structure of the obtained films was analyzed by scanning electron microscopy and transmission electron microscopy. Raman spectroscopy and electron energy-loss spectroscopy recorded at the carbon K-edge region confirm the presence of nanocrystalline diamond. The process is a significant step towards cost-effective and non-cumbersome fabrication of nanocrystalline diamond thin films for commercial production.
Temperature dependence of the energy bandgap of two-dimensional hexagonal boron nitride probed by excitonic photoluminescence
Authors: Du X. Z. , Frye C. D. , Edgar J. H. , Lin J. Y. , Jiang H. X.
Published: February 2014

Hexagonal boron nitride (hBN) is an emerging material for the exploration of new physics in two-dimensional (2D) systems that are complementary to graphene. Nanotubes with a diameter (∼60 nm) that is much larger than the exciton binding energy in hBN have been synthesized and utilized to probe the fundamental optical transitions and the temperature dependence of the energy bandgap of the corresponding 2D hBN sheets. An excitonic transition at 5.901 eV and its longitudinal optical phonon replica at 5.735 eV were observed. The excitonic emission line is blue shifted by about 130 meV with respect to that in hBN bulk crystals due to the effects of reduced dimensionality. The temperature evolution of the excitonic emission line measured from 300 to 800 K revealed that the temperature coefficient of the energy bandgap of hBN nanotubes with large diameters (or equivalently hBN sheets) is about 0.43 meV/0K, which is a factor of about 5 times smaller than the theoretically predicted value for the transitions between the π and π* bands in hBN bulk crystals and 6 times smaller than the measured value in AlN epilayers with a comparable energy bandgap. The observed weaker temperature dependence of the bandgap than those in 3D hBN and AlN is a consequence of the effects of reduced dimensionality in layer-structured hBN.