bluuebunny/crossref_metadata_2025 huggingface dataset:
Porträt Catrin Gekle
Authors: Otto Volkmar
Published: March 2016

Catrin Gekle hatte schon eine steile Karriere in der Modebranche hinter sich, als sie ihre Begeisterung für die Gesundheitswirtschaft entdeckte. Heute verantwortet sie beim evangelischen Klinikverbund Ategris den Bereich Veränderungsmanagement und Marketing. Ihr Leitsatz ist: “Man muss die Chancen einer Krise nutzen, mutig neue Wege gehen und so Perspektiven schaffen – für Patienten und Mitarbeiter gleichermaßen!”
Informationstechnologie im Krankenhaus
Authors: Thalmayr Maria
Published: March 2016

Verbandsnachrichten der FKT - Fachvereinigung Krankenhaustechnik (e. V.). Diese Seiten sind nur als PDF-Dokument verfügbar.
Senior-Experten unter neuer Leitung
Authors: Thalmayr Maria
Published: March 2016

Verbandsnachrichten der FKT - Fachvereinigung Krankenhaustechnik (e. V.). Diese Seiten sind nur als PDF-Dokument verfügbar.
Vergütungs­analyse
Authors: Thalmayr Maria
Published: March 2016

Verbandsnachrichten der FKT - Fachvereinigung Krankenhaustechnik (e. V.). Diese Seiten sind nur als PDF-Dokument verfügbar.
1.2 C—C Bond Formation by Hetarene C—H Activation
Authors: Nakao Y.
Published: March 2016

Heteroaromatic compounds play key roles in pharmaceuticals, agrochemicals, and materials, and the development of efficient synthetic methods to access differently substituted hetarenes is therefore an important issue in organic synthesis. To circumvent the limitations associated with classical protocols to form hetaryl—carbon bonds, metal-catalyzed hetarene C—H activation followed by C—C bond-forming reactions has been developed extensively in recent decades. These transformations allow the construction of C—C bonds between hetaryl moieties and all the three differently hybridized carbons to result in alkylation, alkenylation, acylation, alkynylation, etc. of a diverse range of hetarenes irrespective of their electronic characters. This chapter deals with C—C bond formation by hetarene C—H activation achieved by transition-metal catalysis.
Choosing E-commerce Strategies: A Case Study of eBay.vn Partnership
Authors: Le-Nguyen Khuong , Guo Yue
Published: March 2016

The case uses the story of one of the leading e-commerce firms in Vietnam to introduce students to concepts and models of e-commerce, and in particular, to help students get familiar with cultural, ethical and legal issues in doing cross-border e-commerce. After solving the top three challenges in doing e-commerce in Vietnam within the past 9 years – enabling a reliable and secured online transaction, building customers’ trust in buyers and providing an effective shipping service, the CEO needed to consider whether he should expand his proven successful domestic ecosystem extensively or build a completely new one to serve his company's strategic move: doing cross-border e-commerce in Southeast Asia where there exist established players in the highly competitive and technology savvy market. Such a key strategic event occurred in early 2014.
A passive terahertz video camera based on lumped element kinetic inductance detectors
Authors: Rowe Sam , Pascale Enzo , Doyle Simon , Dunscombe Chris , Hargrave Peter , Papageorgio Andreas , Wood Ken , Ade Peter A. R. , Barry Peter , Bideaud Aurélien , Brien Tom , Dodd Chris , Grainger William , House Julian , Mauskopf Philip , Moseley Paul , Spencer Locke , Sudiwala Rashmi , Tucker Carole , Walker Ian
Published: March 2016

We have developed a passive 350 GHz (850 μm) video-camera to demonstrate lumped element kinetic inductance detectors (LEKIDs)—designed originally for far-infrared astronomy—as an option for general purpose terrestrial terahertz imaging applications. The camera currently operates at a quasi-video frame rate of 2 Hz with a noise equivalent temperature difference per frame of ∼0.1 K, which is close to the background limit. The 152 element superconducting LEKID array is fabricated from a simple 40 nm aluminum film on a silicon dielectric substrate and is read out through a single microwave feedline with a cryogenic low noise amplifier and room temperature frequency domain multiplexing electronics.
Electron-bombarded 〈110〉-oriented tungsten tips for stable tunneling electron emission
Authors: Yamada T. K. , Abe T. , Nazriq N. M. K. , Irisawa T.
Published: March 2016

A clean tungsten (W) tip apex with a robust atomic plane is required for producing a stable tunneling electron emission under strong electric fields. Because a tip apex fabricated from a wire by aqueous chemical etching is covered by impurity layers, heating treatment in ultra-high vacuum is experimentally known to be necessary. However, strong heating frequently melts the tip apex and causes unstable electron emissions. We investigated quantitatively the tip apex and found a useful method to prepare a tip with stable tunneling electron emissions by controlling electron-bombardment heating power. Careful characterizations of the tip structures were performed with combinations of using field emission I–V curves, scanning electron microscopy, X-ray diffraction (transmitted Debye-Scherrer and Laue) with micro-parabola capillary, field ion microscopy, and field emission microscopy. Tips were chemically etched from (1) polycrystalline W wires (grain size ∼1000 nm) and (2) long-time heated W wires (grain size larger than 1 mm). Heating by 10-40 W (10 s) was found to be good enough to remove oxide layers and produced stable electron emission; however, around 60 W (10 s) heating was threshold power to increase the tip radius, typically +10 ± 5 nm (onset of melting). Further, the grain size of ∼1000 nm was necessary to obtain a conical shape tip apex.
Iterative diagonalization of the non-Hermitian transcorrelated Hamiltonian using a plane-wave basis set: Application to sp-electron systems with deep core states
Authors: Ochi Masayuki , Yamamoto Yoshiyuki , Arita Ryotaro , Tsuneyuki Shinji
Published: March 2016

We develop an iterative diagonalization scheme in solving a one-body self-consistent-field equation in the transcorrelated (TC) method using a plane-wave basis set. Non-Hermiticity in the TC method is well handled with a block-Davidson algorithm. We verify that the required computational cost is efficiently reduced by our algorithm. In addition, we apply our plane-wave-basis TC calculation to some simple sp-electron systems with deep core states to elucidate an impact of the pseudopotential approximation to the calculated band structures. We find that a position of the deep valence bands is improved by an explicit inclusion of core states, but an overall band structure is consistent with a regular setup that includes core states into the pseudopotentials. This study offers an important understanding for the future application of the TC method to strongly correlated solids.
Free surface liquid films of binary mixtures. Two-dimensional steady structures at off-critical compositions
Authors: Bribesh Fathi A. M. , Madruga Santiago
Published: March 2016

We present steady non-linear solutions of films of confined polymer blends deposited on a solid substrate at off-critical concentrations with a free deformable surface. The solutions are obtained numerically using a variational form of the Cahn-Hilliard equation in the static limit, which allows for internal diffuse interfaces between the two components of the mixture. Existence of most of the branches of non-linear solutions at off-critical concentrations can be predicted from the knowledge of the branching points obtained with a linear stability analysis plus the non-linear solutions at critical concentrations. However, some families of solutions are found not to have correspondence at critical compositions. We take a value for surface tension that allows strong deformations at the sharp free upper surface. Varying the average composition and the length and thickness of the films we find a rich morphology of static films in the form of laterally structure films, layered films, droplets on the substrate, droplets at the free surface, and checkerboard structures. We show that laterally structured solutions are energetically favorable over homogeneous and other structured solutions within the whole spinodal region and even close to the absolute stability binodal boundary.
Coupled optical and electrical study of thin-film InGaAs photodetector integrated with surface InP Mie resonators
Authors: Fu Dong , Liu Jietao , Song Jiakun , Yu Hailong , Zhang Zuyin , Wang Wenbo , Xu Yun , Song Guofeng , Wei Xin
Published: March 2016

High-index dielectric and semiconductor nanostructures with characteristics of low absorption loss and artificially controlled scattering properties have grasped an increasing attention for improving the performance of thin-film photovoltaic devices. In this work, combined optical and electrical simulations were performed for thin-film InP/In0.53Ga0.47As/InP hetero-junction photodetector with periodically arranged InP nano-cylinders in the in-coupling configuration. It is found that the carefully designed InP nano-cylinders possess strongly substrate-coupled Mie resonances and can effectively couple incident light into the guided mode, both of which significantly increase optical absorption. Further study from the electrical aspects shows that enhancement of external quantum efficiency is as high as 82% and 83% in the configurations with the optimized nano-cylinders and the optimized period, respectively. Moreover, we demonstrate that the integration of InP nano-cylinders does not degrade the electrical performance, since the surface recombination is effectively suppressed by separating the absorber layer where carriers generate and the air/semiconductor interface. The comprehensive modeling including optical and electrical perspectives provides a more practical description for device performance than the optical-only simulation and is expected to advance the design of thin-film absorber layer based optoelectronic devices for fast response and high efficiency.
CAMEA—A novel multiplexing analyzer for neutron spectroscopy
Authors: Groitl Felix , Graf Dieter , Birk Jonas Okkels , Markó Márton , Bartkowiak Marek , Filges Uwe , Niedermayer Christof , Rüegg Christian , Rønnow Henrik M.
Published: March 2016

The analyzer detector system continuous angle multiple energy analysis will be installed on the cold-neutron triple-axis spectrometer RITA-2 at SINQ, PSI. CAMEA is optimized for efficiency in the horizontal scattering plane enabling rapid and detailed mapping of excitations. As a novelty the design employs a series of several sequential upward scattering analyzer arcs. Each arc is set to a different, fixed, final energy and scatters neutrons towards position sensitive detectors. Thus, neutrons with different final energies are recorded simultaneously over a large angular range. In a single data-acquisition many entire constant-energy lines in the horizontal scattering plane are recorded for a quasi-continuous angular coverage of about 60°. With a large combined coverage in energy and momentum, this will result in a very efficient spectrometer, which will be particularly suited for parametric studies under extreme conditions with restrictive sample environments (high field magnets or pressure cells) and for small samples of novel materials. In this paper we outline the concept and the specifications of the instrument currently under construction.
Classification of weld defect based on information fusion technology for radiographic testing system
Authors: Jiang Hongquan , Liang Zeming , Gao Jianmin , Dang Changying
Published: March 2016

Improving the efficiency and accuracy of weld defect classification is an important technical problem in developing the radiographic testing system. This paper proposes a novel weld defect classification method based on information fusion technology, Dempster–Shafer evidence theory. First, to characterize weld defects and improve the accuracy of their classification, 11 weld defect features were defined based on the sub-pixel level edges of radiographic images, four of which are presented for the first time in this paper. Second, we applied information fusion technology to combine different features for weld defect classification, including a mass function defined based on the weld defect feature information and the quartile-method-based calculation of standard weld defect class which is to solve a sample problem involving a limited number of training samples. A steam turbine weld defect classification case study is also presented herein to illustrate our technique. The results show that the proposed method can increase the correct classification rate with limited training samples and address the uncertainties associated with weld defect classification.
Improvement of immunoassay detection system by using alternating current magnetic susceptibility
Authors: Kawabata R. , Mizoguchi T. , Kandori A.
Published: March 2016

A major goal with this research was to develop a low-cost and highly sensitive immunoassay detection system by using alternating current (AC) magnetic susceptibility. We fabricated an improved prototype of our previously developed immunoassay detection system and evaluated its performance. The prototype continuously moved sample containers by using a magnetically shielded brushless motor, which passes between two anisotropic magneto resistance (AMR) sensors. These sensors detected the magnetic signal in the direction where each sample container passed them. We used the differential signal obtained from each AMR sensor’s output to improve the signal-to-noise ratio (SNR) of the magnetic signal measurement. Biotin-conjugated polymer beads with avidin-coated magnetic particles were prepared to examine the calibration curve, which represents the relation between AC magnetic susceptibility change and polymer-bead concentration. For the calibration curve measurement, we, respectively, measured the magnetic signal caused by the magnetic particles by using each AMR sensor installed near the upper or lower part in the lateral position of the passing sample containers. As a result, the SNR of the prototype was 4.5 times better than that of our previous system. Moreover, the data obtained from each AMR sensor installed near the upper part in the lateral position of the passing sample containers exhibited an accurate calibration curve that represented good correlation between AC magnetic susceptibility change and polymer-bead concentration. The conclusion drawn from these findings is that our improved immunoassay detection system will enable a low-cost and highly sensitive immunoassay.
Coupled-cluster based basis sets for valence correlation calculations
Authors: Claudino Daniel , Gargano Ricardo , Bartlett Rodney J.
Published: March 2016

Novel basis sets are generated that target the description of valence correlation in atoms H through Ar. The new contraction coefficients are obtained according to the Atomic Natural Orbital (ANO) procedure from CCSD(T) (coupled-cluster singles and doubles with perturbative triples correction) density matrices starting from the primitive functions of Dunning et al. [J. Chem. Phys. 90, 1007 (1989); ibid. 98, 1358 (1993); ibid. 100, 2975 (1993)] (correlation consistent polarized valence X-tuple zeta, cc-pVXZ). The exponents of the primitive Gaussian functions are subject to uniform scaling in order to ensure satisfaction of the virial theorem for the corresponding atoms. These new sets, named ANO-VT-XZ (Atomic Natural Orbital Virial Theorem X-tuple Zeta), have the same number of contracted functions as their cc-pVXZ counterparts in each subshell. The performance of these basis sets is assessed by the evaluation of the contraction errors in four distinct computations: correlation energies in atoms, probing the density in different regions of space via 〈rn〉 (−3 ≤ n ≤ 3) in atoms, correlation energies in diatomic molecules, and the quality of fitting potential energy curves as measured by spectroscopic constants. All energy calculations with ANO-VT-QZ have contraction errors within “chemical accuracy” of 1 kcal/mol, which is not true for cc-pVQZ, suggesting some improvement compared to the correlation consistent series of Dunning and co-workers.
Surface induced magnetization reversal of MnP nanoclusters embedded in GaP
Authors: Lacroix Christian , Lambert-Milot Samuel , Desjardins Patrick , Masut Remo A. , Ménard David
Published: March 2016

We investigate the quasi-static magnetic behavior of ensembles of ferromagnetic nanoparticles consisting of MnP nanoclusters embedded in GaP(001) epilayers grown at 600, 650, and 700 °C. We use a phenomenological model, in which surface effects are included, to reproduce the experimental hysteresis curves measured as a function of temperature (120–260 K) and direction of the applied field. The slope of the hysteresis curve during magnetization reversal is determined by the MnP nanoclusters size distribution, which is a function of the growth temperature. Our results show that the coercive field is very sensitive to the strength of the surface anisotropy, which reduces the energy barrier between the two states of opposite magnetization. Notably, this reduction in the energy barrier increases by a factor of 3 as the sample temperature is lowered from 260 to 120 K.
Efficient estimators for likelihood ratio sensitivity indices of complex stochastic dynamics
Authors: Arampatzis Georgios , Katsoulakis Markos A. , Rey-Bellet Luc
Published: March 2016

We demonstrate that centered likelihood ratio estimators for the sensitivity indices of complex stochastic dynamics are highly efficient with low, constant in time variance and consequently they are suitable for sensitivity analysis in long-time and steady-state regimes. These estimators rely on a new covariance formulation of the likelihood ratio that includes as a submatrix a Fisher information matrix for stochastic dynamics and can also be used for fast screening of insensitive parameters and parameter combinations. The proposed methods are applicable to broad classes of stochastic dynamics such as chemical reaction networks, Langevin-type equations and stochastic models in finance, including systems with a high dimensional parameter space and/or disparate decorrelation times between different observables. Furthermore, they are simple to implement as a standard observable in any existing simulation algorithm without additional modifications.
Carbon dioxide in an ionic liquid: Structural and rotational dynamics
Authors: Giammanco Chiara H. , Kramer Patrick L. , Yamada Steven A. , Nishida Jun , Tamimi Amr , Fayer Michael D.
Published: March 2016

Ionic liquids (ILs), which have widely tunable structural motifs and intermolecular interactions with solutes, have been proposed as possible carbon capture media. To inform the choice of an optimal ionic liquid system, it can be useful to understand the details of dynamics and interactions on fundamental time scales (femtoseconds to picoseconds) of dissolved gases, particularly carbon dioxide (CO2), within the complex solvation structures present in these uniquely organized materials. The rotational and local structural fluctuation dynamics of CO2 in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimNTf2) were investigated by using ultrafast infrared spectroscopy to interrogate the CO2 asymmetric stretch. Polarization-selective pump probe measurements yielded the orientational correlation function of the CO2 vibrational transition dipole. It was found that reorientation of the carbon dioxide occurs on 3 time scales: 0.91 ± 0.03, 8.3 ± 0.1, 54 ± 1 ps. The initial two are attributed to restricted wobbling motions originating from a gating of CO2 motions by the IL cations and anions. The final (slowest) decay corresponds to complete orientational randomization. Two-dimensional infrared vibrational echo (2D IR) spectroscopy provided information on structural rearrangements, which cause spectral diffusion, through the time dependence of the 2D line shape. Analysis of the time-dependent 2D IR spectra yields the frequency-frequency correlation function (FFCF). Polarization-selective 2D IR experiments conducted on the CO2 asymmetric stretch in the parallel- and perpendicular-pumped geometries yield significantly different FFCFs due to a phenomenon known as reorientation-induced spectral diffusion (RISD), revealing strong vector interactions with the liquid structures that evolve slowly on the (independently measured) rotation time scales. To separate the RISD contribution to the FFCF from the structural spectral diffusion contribution, the previously developed first order Stark effect RISD model is reformulated to describe the second order (quadratic) Stark effect—the first order Stark effect vanishes because CO2 does not have a permanent dipole moment. Through this analysis, we characterize the structural fluctuations of CO2 in the ionic liquid solvation environment, which separate into magnitude-only and combined magnitude and directional correlations of the liquid’s time dependent electric field. This new methodology will enable highly incisive comparisons between CO2 dynamics in a variety of ionic liquid systems.
Kinetic Monte Carlo simulations for birefringence relaxation of photo-switchable molecules on a surface
Authors: Tavarone Raffaele , Charbonneau Patrick , Stark Holger
Published: March 2016

Recent experiments have demonstrated that in a dense monolayer of photo-switchable dye methyl-red molecules the relaxation of an initial birefringence follows a power-law decay, typical for glass-like dynamics. The slow relaxation can efficiently be controlled and accelerated by illuminating the monolayer with circularly polarized light, which induces trans-cis isomerization cycles. To elucidate the microscopic mechanism, we develop a two-dimensional molecular model in which the trans and cis isomers are represented by straight and bent needles, respectively. As in the experimental system, the needles are allowed to rotate and to form overlaps but they cannot translate. The out-of-equilibrium rotational dynamics of the needles is generated using kinetic Monte Carlo simulations. We demonstrate that, in a regime of high density and low temperature, the power-law relaxation can be traced to the formation of spatio-temporal correlations in the rotational dynamics, i.e., dynamic heterogeneity. We also show that the nearly isotropic cis isomers can prevent dynamic heterogeneity from forming in the monolayer and that the relaxation then becomes exponential.
Tracking mechanical and morphological dynamics of regenerating Hydra tissue fragments using a two fingered micro-robotic hand
Authors: Veschgini M. , Gebert F. , Khangai N. , Ito H. , Suzuki R. , Holstein T. W. , Mae Y. , Arai T. , Tanaka M.
Published: March 2016

Regeneration of a tissue fragment of freshwater polyp Hydra is accompanied by significant morphological fluctuations, suggesting the generation of active forces. In this study, we utilized a two fingered micro-robotic hand to gain insights into the mechanics of regenerating tissues. Taking advantage of a high force sensitivity (∼1 nN) of our micro-hand, we non-invasively acquired the bulk elastic modulus of tissues by keeping the strain levels low (ε < 0.15). Moreover, by keeping the strain at a constant level, we monitored the stress relaxation of the Hydra tissue and determined both viscous modulus and elastic modulus simultaneously, following a simple Maxwell model. We further investigated the correlation between the frequency of force fluctuation and that of morphological fluctuation by monitoring one “tweezed” tissue and the other “intact” tissue at the same time. The obtained results clearly indicated that the magnitude and periodicity of the changes in force and shape are directly correlated, confirming that our two fingered micro-hand can precisely quantify the mechanics of soft, dynamic tissue during the regeneration and development in a non-invasive manner.
Magnetically launched flyer plate technique for probing electrical conductivity of compressed copper
Authors: Cochrane K. R. , Lemke R. W. , Riford Z. , Carpenter J. H.
Published: March 2016

The electrical conductivity of materials under extremes of temperature and pressure is of crucial importance for a wide variety of phenomena, including planetary modeling, inertial confinement fusion, and pulsed power based dynamic materials experiments. There is a dearth of experimental techniques and data for highly compressed materials, even at known states such as along the principal isentrope and Hugoniot, where many pulsed power experiments occur. We present a method for developing, calibrating, and validating material conductivity models as used in magnetohydrodynamic (MHD) simulations. The difficulty in calibrating a conductivity model is in knowing where the model should be modified. Our method isolates those regions that will have an impact. It also quantitatively prioritizes which regions will have the most beneficial impact. Finally, it tracks the quantitative improvements to the conductivity model during each incremental adjustment. In this paper, we use an experiment on Sandia National Laboratories Z-machine to isentropically launch multiple flyer plates and, with the MHD code ALEGRA and the optimization code DAKOTA, calibrated the conductivity such that we matched an experimental figure of merit to +/−1%.
Temperature induced modification of the mid-infrared response of single-walled carbon nanotubes
Authors: Shuba Mikhail V. , Paddubskaya Alesia G. , Kuzhir Polina P. , Maksimenko Sergey A. , Valusis Gintaras , Poklonski Nikolai A. , Bellucci Stefano , Kenanakis George , Kafesaki Maria
Published: March 2016

The temperature dependences of the absorbance spectra of thin free-standing single-walled carbon nanotube (SWCNT) films were studied in the infrared range (700–6200 cm−1) while heating the air from 300 to 575 K. The observed temperature variation in the infrared absorbance spectra has been explained by two different physical factors. The first one is the strong temperature dependence of the conductivity of p-type doped semiconducting SWCNTs. The second one is the temperature dependence of electron relaxation time of intraband electron transitions in metallic SWCNTs. The possibility of the separation of contributions from the interband and intraband transitions to the infrared spectra of SWCNT films has been demonstrated.
Temperature dependent electron delocalization in CdSe/CdS type-I core-shell systems: An insight from scanning tunneling spectroscopy
Authors: Kundu Biswajit , Chakrabarti Sudipto , Pal Amlan J.
Published: March 2016

Core-shell nanocrystals having a type-I band-alignment confine charge carriers to the core. In this work, we choose CdSe/CdS core-shell nano-heterostructures that evidence confinement of holes only. Such a selective confinement occurs in the core-shell nanocrystals due to a low energy-offset of conduction band (CB) edges resulting in delocalization of electrons and thus a decrease in the conduction band-edge. Since the delocalization occurs through a thermal assistance, we study temperature dependence of selective delocalization process through scanning tunneling spectroscopy. From the density of states (DOS), we observe that the electrons are confined to the core at low temperatures. Above a certain temperature, they become delocalized up to the shell leading to a decrease in the CB of the core-shell system due to widening of quantum confinement effect. With holes remaining confined to the core due to a large offset in the valence band (VB), we record the topography of the core-shell nanocrystals by probing their CB and VB edges separately. The topographies recorded at different temperatures representing wave-functions of electrons and holes corresponded to the results obtained from the DOS spectra. The results evidence temperature-dependent wave-function delocalization of one-type of carriers up to the shell layer in core-shell nano-heterostructures.
Effect of resonant magnetic perturbations on three dimensional equilibria in the Madison Symmetric Torus reversed-field pinch
Authors: Munaretto S. , Chapman B. E. , Nornberg M. D. , Boguski J. , DuBois A. M. , Almagri A. F. , Sarff J. S.
Published: March 2016

The orientation of 3D equilibria in the Madison Symmetric Torus (MST) [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)] reversed-field pinch can now be controlled with a resonant magnetic perturbation (RMP). Absent the RMP, the orientation of the stationary 3D equilibrium varies from shot to shot in a semi-random manner, making its diagnosis difficult. Produced with a poloidal array of saddle coils at the vertical insulated cut in MST's thick conducting shell, an m = 1 RMP with an amplitude br/B ∼ 10% forces the 3D structure into any desired orientation relative to MST's diagnostics. This control has led to improved diagnosis, revealing enhancements in both the central electron temperature and density. With sufficient amplitude, the RMP also inhibits the generation of high-energy (>20 keV) electrons, which otherwise emerge due to a reduction in magnetic stochasticity in the core. Field line tracing reveals that the RMP reintroduces stochasticity to the core. A m = 3 RMP of similar amplitude has little effect on the magnetic topology or the high-energy electrons.
Analysis of a picosecond ultrasonic method for measurement of stress in a substrate
Authors: Dai J. , Mukundhan P. , Kim C. , Maris H. J.
Published: March 2016

We report on a method for determining the stress near the surface of a crystal that is partly transparent. A pump light pulse is applied to the sample to set up a stress near to the sample surface. This stress relaxes and launches a strain pulse into the sample. The propagation of this strain pulse can be monitored by means of a time-delayed optical probe pulse. The reflectivity of this probe light pulse contains a component which varies periodically with the time delay. We show how the period of this component can be precisely extracted from the data, how the period can be used to determine the stress in the sample, and the sensitivity of the technique for stress measurements.
Communication: GAIMS—Generalized Ab Initio Multiple Spawning for both internal conversion and intersystem crossing processes
Authors: Curchod Basile F. E. , Rauer Clemens , Marquetand Philipp , González Leticia , Martínez Todd J.
Published: March 2016

Full multiple spawning is a formally exact method to describe the excited-state dynamics of molecular systems beyond the Born-Oppenheimer approximation. However, it has been limited until now to the description of radiationless transitions taking place between electronic states with the same spin multiplicity. This Communication presents a generalization of the full and ab initio multiple spawning methods to both internal conversion (mediated by nonadiabatic coupling terms) and intersystem crossing events (triggered by spin-orbit coupling matrix elements) based on a spin-diabatic representation. The results of two numerical applications, a model system and the deactivation of thioformaldehyde, validate the presented formalism and its implementation.
Design of an adjustable polarization-independent and wideband electromagnetic absorber
Authors: He Yun , Jiang Jianjun , Chen Mi , Li Shicai , Miao Ling , Bie Shaowei
Published: March 2016

An adjustable polarization-independent electromagnetic absorber based on a frequency-selective surface is proposed for both C and X microwave-band applications. The design using a symmetric fan-shaped pattern significantly reduces the sensitivity to different polarizations of normal incident microwaves. To achieve adjustability, PIN diodes are connected between patterned unit cells. By incorporating inductors into the metal patterns, an S-shaped series bias provides the bias voltage to PIN diodes. By tuning the working states of the diodes, an adjustable absorption performance from 4.6 to 13 GHz is achieved for both transverse electric and transverse magnetic polarizations in normal incidence.
Numerical investigation of shock interaction with one-dimensional transverse array of particles in air
Authors: Mehta Y. , Jackson T. L. , Zhang J. , Balachandar S.
Published: March 2016

In this paper, we present numerical simulations of shock propagation in air over a one-dimensional transverse array of particles. Simulations are carried out by varying the particle spacing and shock Mach number. We compute the unsteady inviscid drag coefficient as a function of time and make relevant comparisons to that for a single particle. We find that deviations in the drag coefficient in time from that of a single particle can be correlated to the acoustic-particle interaction time. Finally, we investigate and classify the interaction of the bow shocks in front of the transverse array of particles.
New insights into the red and green pigments in the illuminated foral charter of Setubal (1515) by combined use of μ-Raman and X-ray fluorescence spectrometry
Authors: Guerra M. , Carvalho M. L. , Le Gac A. , Manso M. , Mortari C. , Longelin S. , Pessanha S.
Published: March 2016

The richly decorated foral charter attributed by D. Manuel I of Portugal, in 1515, to the village of Setubal, was studied using Energy Dispersive X-ray Fluorescence spectrometry and Raman micro-spectroscopy. An in situ characterization of the pigments used in the production of this masterpiece showed a very different pigment palette choice when compared to other similar Manueline charters. The red and green pigments are particularly puzzling, as the widely used mercury- and copper-based pigments, vermillion and malachite, respectively, were not found in the illuminated frontispiece. Instead, the cheaper lead-based pigment minium was used in the King's flag, while a mixture of copper sulfates was found for the green color, identified by means of micro-Raman spectroscopy. This result led to a new look at the conception that only one Royal workshop existed for the elaboration of Manueline foral charters.
Towards a feasible implementation of quantum neural networks using quantum dots
Authors: Altaisky Mikhail V. , Zolnikova Nadezhda N. , Kaputkina Natalia E. , Krylov Victor A. , Lozovik Yurii E. , Dattani Nikesh S.
Published: March 2016

We propose an implementation of quantum neural networks using an array of quantum dots with dipole-dipole interactions. We demonstrate that this implementation is both feasible and versatile by studying it within the framework of GaAs based quantum dot qubits coupled to a reservoir of acoustic phonons. Using numerically exact Feynman integral calculations, we have found that the quantum coherence in our neural networks survive for over a hundred ps even at liquid nitrogen temperatures (77 K), which is three orders of magnitude higher than current implementations, which are based on SQUID-based systems operating at temperatures in the mK range.
A solid-state dielectric elastomer switch for soft logic
Authors: Chau Nixon , Slipher Geoffrey A. , O'Brien Benjamin M. , Mrozek Randy A. , Anderson Iain A.
Published: March 2016

In this paper, we describe a stretchable solid-state electronic switching material that operates at high voltage potentials, as well as a switch material benchmarking technique that utilizes a modular dielectric elastomer (artificial muscle) ring oscillator. The solid-state switching material was integrated into our oscillator, which self-started after 16 s and performed 5 oscillations at a frequency of 1.05 Hz with 3.25 kV DC input. Our materials-by-design approach for the nickel filled polydimethylsiloxane based switch has resulted in significant improvements over previous carbon grease-based switches in four key areas, namely, sharpness of switching behavior upon applied stretch, magnitude of electrical resistance change, ease of manufacture, and production rate. Switch lifetime was demonstrated to be in the range of tens to hundreds of cycles with the current process. An interesting and potentially useful strain-based switching hysteresis behavior is also presented.
Influence of phonon reservoir on photon blockade in a driven quantum dot-cavity system
Authors: Gao Bo , Zhu Jia-pei , Li Gao-xiang
Published: March 2016

We theoretically investigate the influence of the phonon bath on photon blockade in a simultaneously driven dot-cavity system. An optimal condition for avoiding two-photon excitation of a cavity field is put forward which can be achieved by modulating the phase difference and the strengths of the driving fields. The second-order correlation function and the mean photon number of the cavity field are discussed. In the absence of phonon effect, the strong photon blockade in a moderate quantum dot (QD)-cavity coupling regime occurs, which can be attributed to the destructive quantum interference arisen from different transition paths induced by simultaneously driving the dressed QD-cavity system. The participation of acoustic-phonon reservoir produces new transition channels for the QD-cavity system, which leads to the damage of destructive interference. As a result, the photon blockade effect is hindered when taking the electron-phonon interaction into account. It is also found that the temperature of the phonon reservoir is disadvantageous for the generation of photon blockade.
Reduced contact resistance in top-contact organic field-effect transistors by interface contact doping
Authors: Hou Ji-Ling , Kasemann Daniel , Widmer Johannes , Günther Alrun A. , Lüssem Björn , Leo Karl
Published: March 2016

Emerging organic integrated electronics require capability of high speed and the compatibility with high-resolution structuring processes such as photolithography. When downscaling the channel length, the contact resistance is known to limit the performance of the short channel devices. In this report, orthogonal photolithography is used for the patterning of the source/drain electrodes of the organic field-effect transistors (OFETs) as well as the interface dopant insertion layers for further modifications of the contact resistance. Bottom-gate top-contact pentacene OFETs with different thicknesses of the p-dopant 2,2′-(perfluoronaphthalene-2,6-diylidene)dimalononitrile under the Au electrodes show a significant decrease in threshold voltage from −2.2 V to −0.8 V and in contact resistance from 55 kΩ cm to 10 kΩ cm by adding a 1 nm thin dopant interlayer. The influence of doping on charge carrier injection is directly visible in the temperature-dependent output characteristics and a charge-transfer activation energy of ∼20 meV is obtained. Our results provide a systematic study of interface contact doping and also show the connection between interface contact doping and improved charge carrier injection by the activation of charge transfer process.
Lead nitrate hydroxide: A strong second-order optical nonlinearity acentric crystal with high laser damage thresholds
Authors: Reshak A. H.
Published: March 2016

A comprehensive theoretical calculation for the complex first-order linear and the second-order non-linear optical dispersion of acentric lead nitrate hydroxide (Pb16(OH)16(NO3)16) single crystals was performed based on the experimental crystallographic data obtained by Chang et al. [Inorg. Chem. 53, 3320–3325 (2014)]. Calculations show an energy band gap of about 3.70 eV, in close agreement to the measured one (3.78 eV). The energy gap value confirms that the Pb16(OH)16(NO3)16 single crystal exhibits an exceptional laser damage threshold. The complex first-order linear optical dispersion helps to get deep insight into the electronic structure and reveals the existence of considerable anisotropy, negative uniaxial anisotropy, and positive birefringence. The calculated second harmonic generation of Pb16(OH)16(NO3)16 at wavelength (λ = 1064 nm) shows a good agreement with the reported measured value. In addition, the microscopic first hyperpolarizability was obtained at the static limit and at the wavelength 1064 nm.
Systematic study of Ge1−xSnx absorption coefficient and refractive index for the device applications of Si-based optoelectronics
Authors: Tran Huong , Du Wei , Ghetmiri Seyed A. , Mosleh Aboozar , Sun Greg , Soref Richard A. , Margetis Joe , Tolle John , Li Baohua , Naseem Hameed A. , Yu Shui-Qing
Published: March 2016

The absorption coefficient and refractive index of Ge1−xSnx alloys (x from 0% to 10%) were characterized for the wavelength range from 1500 to 2500 nm via spectroscopic ellipsometry at room temperature. By applying physical models to fit the obtained data, two empirical formulae with extracted constants and coefficients were developed: (1) Absorption coefficient. The absorption regarding Urbach tail, indirect and direct bandgap transitions were comprehensively taken into account; (2) refractive index. The Sellmeier coefficients associated with dispersion relationship were extracted. In these formulae, the Sn composition and strain percentage were the input parameters, by inputting which the spectral absorption coefficient and spectral refractive index can be obtained. Since the absorption coefficient is key information to determine the performance of the photodetectors including operation wavelength range, responsivity, and specific detectivity, and the refractive index is very useful for the design of the anti-reflection coating for photodetectors and the layer structure for waveguides, the developed formulae could simplify the optoelectronic device design process due to their parameter-based expressions.
Current crowding in two-dimensional black-phosphorus field-effect transistors
Authors: Wang Q. , Tao X. , Yang L. , Gu Y.
Published: March 2016

By combining electrical measurements, scanning Kelvin probe microscopy, and numerical electrical simulations, we find significant current crowding in two-dimensional (2D) black phosphorus field-effect transistors. This current crowding can lead to localized Joule heating close to the metal contacts, and it is consistent with the features of the device failure observed in this study. Importantly, by considering both Schottky and resistive Ohmic contact models, we find that the commonly used transmission-line model, in general, significantly underestimates the extent of the current crowding. These findings, which are likely to be relevant in other 2D materials, suggest the need to take into account the current crowding effect in designing 2D devices.
Magneto-transport and domain wall scattering in epitaxy L1 MnAl thin film
Authors: Luo Linqiang , Anuniwat Nattawut , Dao Nam , Cui Yishen , Wolf Stuart A. , Lu Jiwei
Published: March 2016

This work demonstrated two different kinds of magneto-transport behaviors in epitaxial L10 MnAl film as a function of temperature. The magneto-resistance ratio (MR) was negative and exhibited evident enhancement in the resistivity at coercive fields above 175 K. The MR enhancement was attributed to the increase in the magnetic domain walls based on the quantitative correlation between the domain density and the resistivity. Below 175 K, the MR was positive and showed a quadratic dependence on the external magnetic field, which implied that the MR was dominated by Lorentz effects.
A first-principles study on the mechanism of screening depolarizing field in two-dimensional BaTiO3 nanosheets
Authors: Gao Haigen , Yue Zhenxing , Li Longtu
Published: March 2016

A first-principles method is employed to study the mechanism of screening depolarizing field in two-dimensional BaTiO3 nanosheets. The geometric structures and ferroelectric properties show that the low-dimensional BaTiO3 with thickness m = 3 is a freestanding ultrathin film. Therefore, the scale of BaTiO3 nanosheets is defined as m = 1 and 2. The stable domain period corresponding to m = 1, 2, and 3 is 2, 2, and 6, respectively. When m = 1 and 2, only the spontaneous polarizations perpendicular to the surfaces are observed, and they are ∼6 and 15 μC/cm2, respectively. This indicates that the depolarizing field still has an effect on spontaneous polarizations. The difference in macroscopic charge density distribution between ferroelectric and paraelectric phases reveals that a dipole is formed at the ferroelectric domain wall, which leads to a decrease in the depolarizing field in the direction [001]. As a consequence, the critical thickness disappears.
The mechanical properties of stored red blood cells measured by a convenient microfluidic approach combining with mathematic model
Authors: Wang Ying , You Guoxing , Chen Peipei , Li Jianjun , Chen Gan , Wang Bo , Li Penglong , Han Dong , Zhou Hong , Zhao Lian
Published: March 2016

The mechanical properties of red blood cells (RBCs) are critical to the rheological and hemodynamic behavior of blood. Although measurements of the mechanical properties of RBCs have been studied for many years, the existing methods, such as ektacytometry, micropipette aspiration, and microfluidic approaches, still have limitations. Mechanical changes to RBCs during storage play an important role in transfusions, and so need to be evaluated pre-transfusion, which demands a convenient and rapid detection method. We present a microfluidic approach that focuses on the mechanical properties of single cell under physiological shear flow and does not require any high-end equipment, like a high-speed camera. Using this method, the images of stretched RBCs under physical shear can be obtained. The subsequent analysis, combined with mathematic models, gives the deformability distribution, the morphology distribution, the normalized curvature, and the Young's modulus (E) of the stored RBCs. The deformability index and the morphology distribution show that the deformability of RBCs decreases significantly with storage time. The normalized curvature, which is defined as the curvature of the cell tail during stretching in flow, suggests that the surface charge of the stored RBCs decreases significantly. According to the mathematic model, which derives from the relation between shear stress and the adherent cells' extension ratio, the Young's moduli of the stored RBCs are also calculated and show significant increase with storage. Therefore, the present method is capable of representing the mechanical properties and can distinguish the mechanical changes of the RBCs during storage. The advantages of this method are the small sample needed, high-throughput, and easy-use, which make it promising for the quality monitoring of RBCs.
Surface morphology and magnetic property of wrinkled FeGa thin films fabricated on elastic polydimethylsiloxane
Authors: Zhang Shuanglan , Zhan Qingfeng , Yu Ying , Liu Luping , Li Huihui , Yang Huali , Xie Yali , Wang Baomin , Xie Shuhong , Li Run-Wei
Published: March 2016

We investigated the surface morphology and the magnetic property of wrinkled Fe81Ga19 (FeGa) thin films fabricated in two different processes onto elastic polydimethylsiloxane (PDMS) substrates. The films obtained by directly depositing Ta and FeGa layers on a pre-strained PDMS substrate display a sinusoidally wrinkled surface and a weak magnetic anisotropy. The wavelength and amplitude of the sinusoidal morphology linearly increase with the metallic layer thickness, while the magnetic anisotropy decreases with increasing FeGa thickness. The other films grown by depositing FeGa layer on a wrinkled Ta/PDMS surface show a remarkable uniaxial magnetic anisotropy. The strength of magnetic anisotropy increases with increasing FeGa thickness. The magnetic anisotropy can be ascribed to the surface anisotropy, the magnetostrictive anisotropy, and the shape anisotropy caused, respectively, by the magnetic charges on wavy morphology, the residual mechanical stress, and the inhomogeneous thickness of FeGa films.