bluuebunny/crossref_metadata_2025 huggingface dataset:
Lithographically fabricated gold nanowire waveguides for plasmonic routers and logic gates
Authors: Gao Long , Chen Li , Wei Hong , Xu Hongxing
Published: May 2018

A lithographic fabrication method is developed to fabricate gold nanowire networks with low surface plasmon propagation loss, in which plasmonic routers and logic gates are realized.
High pressure-assisted low-loading asymmetric organocatalytic conjugate addition of nitroalkanes to chalcones
Authors: Cholewiak Agnieszka , Adamczyk Kamil , Kopyt Michał , Kasztelan Adrian , Kwiatkowski Piotr
Published: May 2018

A highly enantioselective and relatively fast (1–5 h) Michael reaction with substantial reduction of organocatalyst loading (0.2–1 mol%) was developed under high-pressure conditions (up to 9 kbar) and at room temperature.
Bio-based oil gelling agent for effective removal of oil spills from the surface of water
Authors: Lv Peng , Yang Sudong , Ma Peng-Cheng
Published: May 2018

A wheat-bran-based hybrid material is developed and employed as an oil gelling agent to remove oil spills from the surface of water.
Growth promotion of vertical graphene on SiO2/Si by Ar plasma process in plasma-enhanced chemical vapor deposition
Authors: Sui Yanping , Chen Zhiying , Zhang Yanhui , Hu Shike , Liang Yijian , Ge Xiaoming , Li Jing , Yu Guanghui , Peng Songang , Jin Zhi , Liu Xinyu
Published: May 2018

This study investigates the growth promotion of vertically oriented graphene in plasma-enhanced chemical vapor deposition through Ar plasma treatment.
Synthesis of toluene-4-sulfonic acid 2-(2-thiophen-2-yl-phenanthro[9,10-d]imidazol-1-yl)-ethyl ester and its application for sensitive determination of free fatty acids in ginkgo nut and ginkgo leaf by high performance liquid chromatography with fluorescence detection
Authors: Dong Xiuli , Liu Xueying , Chen Xiangming
Published: May 2018

A highly sensitive HPLC-FL method to determine fatty acids was developed utilizing TSTPE as a novel fluorescent labeling reagent.
Mad honey: uses, intoxicating/poisoning effects, diagnosis, and treatment
Authors: Ullah Sana , Khan Shahid Ullah , Saleh Tawfik A. , Fahad Shah
Published: May 2018

Honey has been used as a folk medicine since 2100 BC; however, mad honey is different from normal natural or commercially available honey as it is contaminated with grayanotoxins, which leads to intoxication/poisoning upon consumption.
Oxygen release from metal oxide for repeated hydrogen regeneration by proton irradiation with polyvinylpyrrolidone
Authors: Seo Keumyoung , Lim Taekyung , Jeong Sang-Mi , Ju Sanghyun
Published: May 2018

The reduction of a 3D microporous NiOx structure, used as a metal oxide catalyst, was performed by proton irradiation with polyvinylpyrrolidone (PVP) for hydrogen regeneration.
Zein regulating apatite mineralization, degradability, in vitro cells responses and in vivo osteogenesis of 3D-printed scaffold of n-MS/ZN/PCL ternary composite
Authors: Ru Jiangying , Wei Qiang , Yang Lianqing , Qin Jing , Tang Liangchen , Wei Jie , Guo Lieping , Niu Yunfei
Published: May 2018

Zein regulating apatite mineralization, degradability, cells responses and osteogenesis of 3D-printed scaffold of n-MS/ZN/PCL ternary composite.
Porous MnFe2O4-decorated PB nanocomposites: a new theranostic agent for boosted T1/T2 MRI-guided synergistic photothermal/magnetic hyperthermia
Authors: Zhou Xi , Lv Xiaolin , Zhao Wen , Zhou Tiantian , Zhang Shupeng , Shi Zhan , Ye Shefang , Ren Lei , Chen Zhiwei
Published: May 2018

We synthesized a new theranostic agent of porous MnFe2O4-decorated PB nanocomposites for boosted T1/T2 MRI-guided synergistic photothermal/magnetic hyperthermia.
Formation of different shell structures in lithium-rich layered oxides and their influence on electrochemical properties
Authors: Cao Kai , Wang Kangping , Shen Taotao , Wang Wenlou , Chen Dongming
Published: May 2018

An ultra-thin spinel Li4Mn5O12 shell layer on the surface of lithium-rich oxide particles was investigated.
Crumpled graphene-encapsulated sulfur for lithium–sulfur batteries
Authors: Hu Xianfei , Leng Kaitong , Zhang Cuijuan , Luo Jiayan
Published: May 2018

Sulfur encapsulated in crumpled reduced graphene oxide shows high performance as a cathode for lithium–sulfur batteries.
Defect management and efficient photocatalytic water oxidation reaction over Mg modified SrNbO2N
Authors: Sun Xiaoqin , Liu Gang , Xu Xiaoxiang
Published: May 2018

Although SrNbO2N has a promising band gap of ∼1.8 eV for solar water splitting, its photocatalytic activity is generally very poor under ordinary conditions, we have managed to improve this by Mg modifications.
Large-scale synthesis of porous carbon via one-step CuCl2 activation of rape pollen for high-performance supercapacitors
Authors: Liu Simin , Liang Yeru , Zhou Wan , Hu Wenqiang , Dong Hanwu , Zheng Mingtao , Hu Hang , Lei Bingfu , Xiao Yong , Liu Yingliang
Published: May 2018

Sustainable synthesis methods for the production of porous carbon with appropriate structural properties for use as supercapacitor electrodes are in high demand.
Metal oxide nanoprism-arrays assembled in N-doped carbon foamy nanoplates that have efficient polysulfide-retention for ultralong-cycle-life lithium–sulfur batteries
Authors: Yao Lu , Dong Xinwei , Zhang Chaoran , Hu Nantao , Zhang Yafei
Published: May 2018

A novel ordered structure based on ZnO nanoprism-arrays was fabricated for ultralong-cycle-life Li–S batteries.
PdNi alloy decorated 3D hierarchically N, S co-doped macro–mesoporous carbon composites as efficient free-standing and binder-free catalysts for Li–O2 batteries
Authors: Ren Xiangzhong , Huang Moujie , Luo Shan , Li Yongliang , Deng Libo , Mi Hongwei , Sun Lingna , Zhang Peixin
Published: May 2018

PdNi/N, S co-doped porous carbon on carbon paper delivers superior electrochemical performance as an electrode for Li–O2 batteries.
Response to the Letter to the Editor From Moncrieff (2017) Regarding de Wit et al. (2016), “Characteristics of Auditory Processing Disorders: A Systematic Review”
Authors: de Wit Ellen , Steenbergen Bert , Visser-Bochane Margot I. , van der Schans Cees P. , van Dijk Pim , Luinge Margreet R.
Published: May 2018

Purpose

The purpose of this letter is to respond to Moncrieff's (2017) letter to the editor, “Response to de Wit et al., 2016, ‘Characteristics of Auditory Processing Disorders: A Systematic Review,’” published in May 2017 by the
Journal of Speech, Language, and Hearing Research.

Conclusion

We believe that our original conclusions are valid given the limited evidence that is currently available about the etiology of auditory processing disorders (APD). The focus of our systematic review was to identify the characteristics of children with a diagnosis of APD or a suspicion of APD. The results of our study showed that the characteristics of these children are not specific or limited to the auditory modality but are multimodal instead. In our view, it is incorrect to use the diagnosis APD, because there is not necessarily a specific auditory deficit in a large group of children suffering from listening difficulties. Before we start using any new diagnoses, a better insight into how bottom-up and top-down processes are precisely involved in listening needs to be developed. In addition, more insight is needed with respect to the similarities and differences between the different developmental disorders of children.
Highly sensitive resonant pressure sensor based on mode‐localisation effect
Authors: Hu Zongda , Zhao Qi
Published: May 2018

A novel micro‐silicon resonant pressure sensor with two mechanically coupled resonators is presented. When pressure acts on the diaphragm, the perturbed stress will cause stiffness perturbation, leading to mode‐localisation phenomenon. Therefore, pressure can be sensed by measuring the amplitude ratio shift. This novel structure is achieved by fabrication on silicon‐on‐insulator wafer. The measured result shows that the relative amplitude ratio shift (86,819.9 ppm/kPA) is 197.5 times higher than the shift in resonance frequency (439.6 ppm/kPA).
Endobronchial Ultrasound in Suspected Non-Malignant Mediastinal Lymphadenopathy
Authors: Eickhoff L. , Golpon H. , Zardo P. , Suhling H. , Welte T. , Jonigk D. , Gottlieb J. , Fuehner T.
Published: May 2018

Background Endobronchial ultrasound (EBUS) bronchoscopy with transbronchial needle aspiration (TBNA) is a well-established tool in mediastinal staging in lung cancer and gains importance in exploration of non-malignant lymphadenopathy. The aim of this study was to evaluate the role of EBUS-TBNA in suspected non-malignant diseases.

Methods A retrospective, single-center, observation analysis of endobronchial ultrasound bronchoscopy procedures was performed in a university medical center between March 2013 and July 2015. All patients with suspected non-malignant mediastinal lymphadenopathy were included. Cytopathological and microbiological results of EBUS were compared to clinical diagnosis 6 months after procedure and performance of EBUS was contrasted to malignant indications.

Results During study period, 333 EBUS bronchoscopies in 315 patients with mediastinal lymphadenopathy were performed. 111 out of 315 (35 %) patients had neither primary signs nor history of a malignant disease, categorised as patients with suspected non-malignant disease. 245 lymph nodes were sampled (median size 15 mm [IQR10 – 19]). Preferred station for TBNA was lymph node station 7 (38 %). Cytopathological findings revealed non-specific inflammation (n = 81; 70 %), carcinoma (n = 7; 6 %), epithelioid cell granulomas (n = 20; 17 %). 7 samples (6 %) were non-representative. Microbiologic testing of lymph nodes identified 3 infections (Mycobacteria tuberculosis [n = 2] and Nocardia nova [n = 1]) relevant to antibiotic therapy. Minor adverse events were observed in 9 out of 115 (8 %) patients. Sensitivity of EBUS-TBNA intervention in suspected non-malignant disease was 76 % and specificity 96 %.

Conclusions EBUS-TBNA revealed a specific cause for suspected non-malignant lymphadenopathy in one-third of cases and was associated with excellent specificity. Predominant specific causes were granuloma, besides from tumor. In 3 patients pathogen could be isolated by TBNA.
Pflegerischer Bedarf bei geriatrischen Dialysepatienten
Authors: Essomé Dagmar , Reichardt Michael , Wiegard-Szramek Ina
Published: May 2018

Die Alterung der Gesellschaft verändert das Aufgabenspektrum der Pflege in der Nephrologie. „Waren 2014 noch 27 % der Bevölkerung mindestens 60 Jahre alt, so
werden es 2030 voraussichtlich 35 % der Bevölkerung sein. […] Die fortschreitende Alterung der Gesellschaft zeigt sich besonders deutlich anhand der wachsenden
Zahl der Hochbetagten. 2014 lebten gut 4,5 Millionen Menschen in Deutschland, die mindestens 80 Jahre alt waren. Ihre Zahl wird in den kommenden Jahrzehnten
kontinuierlich steigen und 2050 etwa 9,9 Millionen erreichen“ 1. Der QIN Jahresbericht für 2015 zeigt auf, dass das Alter bei
Dialysebeginn für Hämodialysepatienten im Mittel bei 67,8 Jahren und für Peritonealdialysepatienten bei 61,0 Jahren lag 2.
Training Effects of Alternated and Pulsed Currents on the Quadriceps Muscles of Athletes
Authors: Oliveira Pedro , Modesto Karenina , Bottaro Martim , Babault Nicolas , Durigan João
Published: May 2018

The aim of the study was to evaluate the effects of 6 weeks training with different neuromuscular electrical stimulation (NMES) currents (medium alternated and low-frequency pulsed current) on muscle architecture and neuromuscular performance of competitive athletes. A double-blind controlled and randomized experimental study was carried out with 33 athletes (22.2±2.6 yrs, 74.7±9.8 kg, 176.8±6.0 cm), divided into 3 groups: mid-frequency current (MF, n=12), pulsed current (PC, n=11) and the control group (CG, n=10). Quadriceps maximal voluntary peak torque (PT) and corresponding vastus lateralis electromyographic activity, evoked torque (PT-NMES), vastus lateralis muscle thickness, fascicle length, pennation angle, and level of discomfort were assessed before and after the interventions. NMES training was performed 3 times per week and consisted of 18 sessions, 15 min/session, 6 s duration in each contraction interspersed with 18 s rest. After the training period, muscle thickness increased in the MF and PC groups (p<0.05). PT-NMES increased only in the PC group (p<0.05). All currents produced similar levels of discomfort (p>0.05). Quadriceps NMES training applied through alternated or pulsed currents produced similar effects in architecture and neuromuscular performance in competitive athletes.
Pilot Study of the Gait Deviation Index in Quantifying Overweight Children's Mobility
Authors: Liu Xue-Cheng , Hainsworth Keri , Simpson Pippa , Lyon Roger , Tassone Channing , Weisman Steven
Published: May 2018

Childhood obesity in the United States has more than tripled in the past three decades. Differences in lower extremity kinematics between obese and nonobese children during walking have been investigated, but the validity of using the gait deviation index (GDI) for measuring gait in obese children has not been explored. Nine obese children (13.9 ± 2.4 years old) with a body mass index of 33.3 ± 3.5 participated in the study. Reflective markers were placed on all children in a widely used standard lower extremity marker configuration. All participants walked along a 20-foot walkway at a self-selected speed. The kinematic and kinetic measurements for all children were taken, and the GDI for each subject was calculated. The mean ± standard deviation (SD) GDI of the nine obese children was 88.5 ± 12, which was significantly lower than the GDI of the typically developing children (100 ± 10, p < 0.002). There were no statistically significant correlations between the GDI and the Pediatric Quality of Life (PedsQL) Total score or PedsQL Physical Functioning score. Obese children had a significantly increased anterior pelvic tilt, hip flexion, hip adduction, hip adduction moment, knee flexion, knee valgus, and plantar flexion in stance phase (p < 0.05). While in swing phase, obese children had increased hip adduction and knee varus. The kinematic differences may reveal lower limb mal-alignment in obese children during walking. Overall, the GDI can play a major role in evaluating gait pathology in obese children. Future studies will increase the sample size to further evaluate the correlation between the GDI and functional outcomes.
Compensation of the sheath effects in cylindrical floating probes
Authors: Park Ji-Hwan , Chung Chin-Wook
Published: May 2018

In cylindrical floating probe measurements, the plasma density and electron temperature are overestimated due to sheath expansion and oscillation. To reduce these sheath effects, a compensation method based on well-developed floating sheath theories is proposed and applied to the floating harmonic method. The iterative calculation of the Allen-Boyd-Reynolds equation can derive the floating sheath thickness, which can be used to calculate the effective ion collection area; in this way, an accurate ion density is obtained. The Child-Langmuir law is used to calculate the ion harmonic currents caused by sheath oscillation of the alternating-voltage-biased probe tip. Accurate plasma parameters can be obtained by subtracting these ion harmonic currents from the total measured harmonic currents. Herein, the measurement principles and compensation method are discussed in detail and an experimental demonstration is presented.
Breakdown characteristics of atmospheric dielectric barrier discharge in gas flow condition
Authors: Fan Zhihui , Yan Huijie , Wang Yuying , Liu Yidi , Guo Hongfei , Ren Chunsheng
Published: May 2018

Experimental investigations of the breakdown characteristics of plate-to-plate dielectric barrier discharge excited by an AC source at different gas flow conditions are carried out. The ignition voltage for the appearance of the very first discharge filament and the breakdown voltage in each discharge half cycle in continuous operation are examined. As revealed by the results of the indoor air experiment, the ignition voltage manifests a monotonous increase with the increase in the gas flow rate, while the breakdown voltage has a marked decline at the low gas flow rate and increases slightly as the gas flow rate is higher than 10 m/s. As regards the obvious decreases in the ignition voltage and breakdown voltage, the decrease in the humidity with the increase in the gas flow rate plays a dominant role. As regards the increase in breakdown voltage, the memory effect from the preceding discharge is considered. The losses of metastable particles, together with particles having high translational energy in the gas flow, are considered to be the most critical factors.
Note: 4-bounce neutron polarizer for reflectometry applications
Authors: Nagy B. , Merkel D. G. , Jakab L. , Füzi J. , Veres T. , Bottyán L.
Published: May 2018

A neutron polarizer using four successive reflections on m = 2.5 supermirrors was built and installed at the GINA neutron reflectometer at the Budapest Neutron Centre. This simple setup exhibits 99.6% polarizing efficiency with 80% transmitted intensity of the selected polarization state. Due to the geometry, the higher harmonics in the incident beam are filtered out, while the optical axis of the beam remains intact for easy mounting and dismounting the device in an existing experimental setup.
Optical rotation based chirality detection of enantiomers via weak measurement in frequency domain
Authors: Li Dongmei , Guan Tian , Liu Fang , Yang Anping , He Yonghong , He Qinghua , Shen Zhiyuan , Xin Meiguo
Published: May 2018

A transmission optical rotation detection scheme based on a weak measurement was proposed for the chirality detection of enantiomers. In this transmission weak measurement system in the frequency domain, the optical activity of the chiral liquid sample was estimated with the central wavelength shift, by modifying the preselected polarization state with the optical rotation (OR). The central wavelength shift of output spectra is sensitive to the OR angle but immune to the interference of the refractive index change caused by measuring circumstances. Two isomers of chiral amino acid acquired opposite responses with this system, and a resolution of 2.17 × 10−9 mol/ml for Proline detection could be obtained. Such a resolution is about 2 orders of magnitude higher than that of common methods, which shows a high sensitivity. This proposed weak measurement scenario suggested an approach to polarimetry and provided a way to accurately assess molecular chirality.
Scattering characteristics of electromagnetic waves in time and space inhomogeneous weakly ionized dusty plasma sheath
Authors: Guo Li-xin , Chen Wei , Li Jiang-ting , Ren Yi , Liu Song-hua
Published: May 2018

The dielectric coefficient of a weakly ionised dusty plasma is used to establish a three-dimensional time and space inhomogeneous dusty plasma sheath. The effects of scattering on electromagnetic (EM) waves in this dusty plasma sheath are investigated using the auxiliary differential equation finite-difference time-domain method. Backward radar cross-sectional values of various parameters, including the dust particle radius, charging frequency of dust particles, dust particle concentration, effective collision frequency, rate of the electron density variation with time, angle of EM wave incidence, and plasma frequency, are analysed within the time and space inhomogeneous plasma sheath. The results show the noticeable effects of dusty plasma parameters on EM waves.
Effect of the screened Coulomb disorder on magneto-transport in Weyl semimetals
Authors: Ji Xuan-Ting , Lu Hai-Zhou , Zhu Zhen-Gang , Su Gang
Published: May 2018

The observation of negative longitudinal magnetoresistivity (NLMR) in Weyl semimetals has gained strong support in recent experiments. It is believed that charged impurities play an important role in the measurement of NLMR. We thus employ a screened Coulomb disorder to model charged impurities and derive a general screening length depending on the magnetic field, chemical potential and temperature. We study the magneto-transport in a two-node Weyl semimetal in which the intra-valley scattering and the inter-valley scattering can be explored simultaneously. We also calculate the effect of the misalignment of the external electric field and the magnetic field on the longitudinal and transverse magnetoconductivities, recovering the experimental observations. We show that the former (latter) is suppressed (enhanced) sensitively with the density of the impurity. This feature makes it hard to observe the NLMR in experiments in the heavy doping case. These results may be exploited to explain the sample-dependent observation of NLMR and deepen our understanding of magneto-transport in Weyl semimetals.
Ellipsometry-based combination of isothermal sorption-desorption measurement and temperature programmed desorption technique: A probe for interaction of thin polymer films with solvent vapor
Authors: Efremov Mikhail Yu. , Nealey Paul F.
Published: May 2018

An environmental chamber equipped with an in situ spectroscopic ellipsometer, programmatic vapor pressure control, and variable temperature substrate holder has been designed for studying polymer coating behavior during an exposure to a solvent vapor and also for probing the residual solvent in the film afterwards. Both sorption-desorption cycle at a constant temperature and temperature programmed desorption (TPD) of the residual solvent manifest themselves as a change of the film thickness. Monitoring of ellipsometric angles of the coating allows us to determine the thickness as a function of the vapor pressure or sample temperature. The solvent vapor pressure is precisely regulated by a computer-controlled pneumatics. TPD spectra are recorded during heating of the film in an oil-free vacuum. The vapor pressure control system is described in detail. The system has been tested on 6-170 nm thick polystyrene, poly(methyl methacrylate), and poly(2-vinyl pyridine) films deposited on silicon substrates. Liquid toluene, water, ethanol, isopropanol, cyclohexane, 1,2-dichloroethane, and chlorobenzene were used to create a vapor atmosphere. Typical sorption-desorption and TPD curves are shown. The instrument achieves sub-monolayer sensitivity for adsorption studies on flat surfaces. Polymer-solvent vapor systems with strong interaction demonstrate characteristic absorption-desorption hysteresis spanning from vacuum to the glass transition pressure. Features on the TPD curves can be classified as either glass transition related film contraction or low temperature broad contraction peak. Typical absorption-desorption and TPD dependencies recorded for the 6 nm thick polystyrene film demonstrate the possibility to apply the presented technique for probing size effects in extremely thin coatings.
Nearly defect-free dynamical models of disordered solids: The case of amorphous silicon
Authors: Atta-Fynn Raymond , Biswas Parthapratim
Published: May 2018

It is widely accepted in the materials modeling community that defect-free realistic networks of amorphous silicon cannot be prepared by quenching from a molten state of silicon using classical or ab initio molecular-dynamics (MD) simulations. In this work, we address this long-standing problem by producing nearly defect-free ultra-large models of amorphous silicon, consisting of up to half a million atoms, using classical MD simulations. The structural, topological, electronic, and vibrational properties of the models are presented and compared with experimental data. A comparison of the models with those obtained from using the modified Wooten-Winer-Weaire bond-switching algorithm shows that the models are on par with the latter, which were generated via event-based total-energy relaxations of atomistic networks in the configuration space. The MD models produced in this work represent the highest quality of amorphous-silicon networks so far reported in the literature using MD simulations.
Theoretical prediction of crystallization kinetics of a supercooled Lennard-Jones fluid
Authors: Gunawardana K. G. S. H. , Song Xueyu
Published: May 2018

The first order curvature correction to the crystal-liquid interfacial free energy is calculated using a theoretical model based on the interfacial excess thermodynamic properties. The correction parameter (δ), which is analogous to the Tolman length at a liquid-vapor interface, is found to be 0.48 ± 0.05 for a Lennard-Jones (LJ) fluid. We show that this curvature correction is crucial in predicting the nucleation barrier when the size of the crystal nucleus is small. The thermodynamic driving force (Δμ) corresponding to available simulated nucleation conditions is also calculated by combining the simulated data with a classical density functional theory. In this paper, we show that the classical nucleation theory is capable of predicting the nucleation barrier with excellent agreement to the simulated results when the curvature correction to the interfacial free energy is accounted for.
Pressure dependence of structural properties of ice VII: An ab initio molecular-dynamics study
Authors: Futera Zdenek , English Niall J.
Published: May 2018

The observed anomalous self-diffusivity of ice VII in the region of 10 GPa at ∼400 K has been suggested to arise from a change in proton-hopping mechanism involving a transition from ionic-defect-driven diffusivity to that dominated by diffusion of rotational defects. Here, we report ab initio molecular dynamics to study the structural, hydrogen bonding, electronic, vibrational, and Raman properties of ice VII at this temperature and between 5 and 20 GPa to elucidate any possible hints of intramolecular strain that may serve as precursor events for proton hopping to unfold. We determine such equilibrium properties to be in reasonable agreement with experimental Raman spectra, although we do not detect any water-dissociation and proton-hopping events per se, owing to still-large water-dissociation free-energy barriers.
Connectionist agent-based learning in bank-run decision making
Authors: Huang Weihong , Huang Qiao
Published: May 2018

It is of utter importance for the policy makers, bankers, and investors to thoroughly understand the probability of bank-run (PBR) which was often neglected in the classical models. Bank-run is not merely due to miscoordination (Diamond and Dybvig, 1983) or deterioration of bank assets (Allen and Gale, 1998) but various factors. This paper presents the simulation results of the nonlinear dynamic probabilities of bank runs based on the global games approach, with the distinct assumption that heterogenous agents hold highly correlated but unidentical beliefs about the true payoffs. The specific technique used in the simulation is to let agents have an integrated cognitive-affective network. It is observed that, even when the economy is good, agents are significantly affected by the cognitive-affective network to react to bad news which might lead to bank-run. Both the rise of the late payoffs, R, and the early payoffs, r, will decrease the effect of the affective process. The increased risk sharing might or might not increase PBR, and the increase in late payoff is beneficial for preventing the bank run. This paper is one of the pioneers that links agent-based computational economics and behavioral economics.
Enhancement and control of laser wakefields via a backward Raman amplifier
Authors: Ludwig J. D. , Masson-Laborde P.-E. , Hüller S. , Rozmus W. , Wilks S. C.
Published: May 2018

The Backward Raman Amplifier (BRA) is proposed as a possible scheme for improving laser driven plasma wakefields. One- and two-dimensional particle-in-cell code simulations and a 3-Wave coupling model are presented and compared to demonstrate how the BRA can be applied to the laser wakefield accelerator (LWFA) in the non-relativistic regime to counteract limitations such as pump depletion and diffraction. This article provides a discussion on optimal parameters for the combination of BRA and LWFA and a prescription for a BRA pump frequency chirp to ensure coupling beyond the particle dephasing limit. Simulation results demonstrate a reduction or alleviation of the effects of diffraction and an increase in wake amplitude and sustainability and provide direct insights into new methods of controlling plasma wakes in LWFA and other applications.
Structural stability, enhanced magnetic, piezoelectric, and transport properties in (1-x)BiFeO3–(x)Ba0.70Sr0.30TiO3 nanoparticles
Authors: Sharma Subhash , Singh Vikash , Anshul Avneesh , Siqueiros J. M. , Dwivedi R. K.
Published: May 2018

Multiferroic samples with composition (1-x)BiFeO3-(x)(Ba0.70Sr0.30)TiO3 (BFO-BST) were synthesized using a sol-gel route to study the effect of BST doping on structural, transport, and magnetic properties in BiFeO3 (BFO). X-ray diffraction studies with Rietveld analysis revealed that a phase transition occurred from rhombohedral (R3c) (0.0 ≤ × ≤ 0.15) to tetragonal (P4 mm) for x = 0.20 and nanocrystalline nature confirmed by transmission electron microscopy measurements. Piezoelectric properties improved as x increased from x = 0.0 (58 pC/N) to x = 0.20 (112 pC/N) increasing distortion in the crystal structure as evinced by Williamson-Hall analysis. Ferromagnetism was observed in doped BFO, different from the antiferromagnetic ordering in bulk BFO, indicating the noteworthy size effects and Fe-O-Fe bond angle variations in the magnetic ordering of BFO. An improvement in ferroelectric properties is observed with doping of BST compared to pristine BFO. Thermally activated conduction behavior occurred at low and high temperature regions as revealed by temperature dependent dc resistivity measurement. Effective improvements in dielectric response, meaning high dielectric constant with a low dielectric loss, were found in the doped samples.
Less is more: Sampling chemical space with active learning
Authors: Smith Justin S. , Nebgen Ben , Lubbers Nicholas , Isayev Olexandr , Roitberg Adrian E.
Published: May 2018

The development of accurate and transferable machine learning (ML) potentials for predicting molecular energetics is a challenging task. The process of data generation to train such ML potentials is a task neither well understood nor researched in detail. In this work, we present a fully automated approach for the generation of datasets with the intent of training universal ML potentials. It is based on the concept of active learning (AL) via Query by Committee (QBC), which uses the disagreement between an ensemble of ML potentials to infer the reliability of the ensemble’s prediction. QBC allows the presented AL algorithm to automatically sample regions of chemical space where the ML potential fails to accurately predict the potential energy. AL improves the overall fitness of ANAKIN-ME (ANI) deep learning potentials in rigorous test cases by mitigating human biases in deciding what new training data to use. AL also reduces the training set size to a fraction of the data required when using naive random sampling techniques. To provide validation of our AL approach, we develop the COmprehensive Machine-learning Potential (COMP6) benchmark (publicly available on GitHub) which contains a diverse set of organic molecules. Active learning-based ANI potentials outperform the original random sampled ANI-1 potential with only 10% of the data, while the final active learning-based model vastly outperforms ANI-1 on the COMP6 benchmark after training to only 25% of the data. Finally, we show that our proposed AL technique develops a universal ANI potential (ANI-1x) that provides accurate energy and force predictions on the entire COMP6 benchmark. This universal ML potential achieves a level of accuracy on par with the best ML potentials for single molecules or materials, while remaining applicable to the general class of organic molecules composed of the elements CHNO.
Agents' beliefs and economic regimes polarization in interacting markets
Authors: Cavalli F. , Naimzada A. K. , Pecora N. , Pireddu M.
Published: May 2018

In the present paper, a model of a market consisting of real and financial interacting sectors is studied. Agents populating the stock market are assumed to be not able to observe the true underlying fundamental, and their beliefs are biased by either optimism or pessimism. Depending on the relevance they give to beliefs, they select the best performing strategy in an evolutionary perspective. The real side of the economy is described within a multiplier-accelerator framework with a nonlinear, bounded investment function. We study the effect of market integration, in particular, of the financialization of the real market. We show that strongly polarized beliefs in an evolutionary framework can introduce multiplicity of steady states, which, consisting in enhanced or depressed levels of income, reflect and reproduce the optimistic or pessimistic nature of the agents' beliefs. The polarization of these steady states, which coexist with an unbiased steady state, positively depends on that of the beliefs and on their relevance. Moreover, with a mixture of analytical and numerical tools, we show that such static characterization is inherited also at the dynamical level, with possibly complex attractors that are characterized by endogenously fluctuating pessimistic and optimistic prices and levels of national income, with the effect of having several coexisting business cycles. This framework, when stochastic perturbations are included, is able to account for stylized facts commonly observed in real financial markets, such as fat tails and excess volatility in the returns distributions, as well as bubbles and crashes for stock prices.
A financial market model with two discontinuities: Bifurcation structures in the chaotic domain
Authors: Panchuk Anastasiia , Sushko Iryna , Westerhoff Frank
Published: May 2018

We continue the investigation of a one-dimensional piecewise linear map with two discontinuity points. Such a map may arise from a simple asset-pricing model with heterogeneous speculators, which can help us to explain the intricate bull and bear behavior of financial markets. Our focus is on bifurcation structures observed in the chaotic domain of the map's parameter space, which is associated with robust multiband chaotic attractors. Such structures, related to the map with two discontinuities, have been not studied before. We show that besides the standard bandcount adding and bandcount incrementing bifurcation structures, associated with two partitions, there exist peculiar bandcount adding and bandcount incrementing structures involving all three partitions. Moreover, the map's three partitions may generate intriguing bistability phenomena.
Modeling temperature dependent singlet exciton dynamics in multilayered organic nanofibers
Authors: de Sousa Leonardo Evaristo , de Oliveira Neto Pedro Henrique , Kjelstrup-Hansen Jakob , da Silva Filho Demétrio Antônio
Published: May 2018

Organic nanofibers have shown potential for application in optoelectronic devices because of the tunability of their optical properties. These properties are influenced by the electronic structure of the molecules that compose the nanofibers and also by the behavior of the excitons generated in the material. Exciton diffusion by means of Förster resonance energy transfer is responsible, for instance, for the change with temperature of colors in the light emitted by systems composed of different types of nanofibers. To study in detail this mechanism, we model temperature dependent singlet exciton dynamics in multilayered organic nanofibers. By simulating absorption and emission spectra, the possible Förster transitions are identified. Then, a kinetic Monte Carlo model is employed in combination with a genetic algorithm to theoretically reproduce time-resolved photoluminescence measurements for several temperatures. This procedure allows for the obtainment of different information regarding exciton diffusion in such a system, including temperature effects on the Förster transfer efficiency and the activation energy of the Förster mechanism. The method is general and may be employed for different systems where exciton diffusion plays a role.
Reconstruction of the static magnetic field of a magnetron
Authors: Krüger Dennis , Köhn Kevin , Gallian Sara , Brinkmann Ralf Peter
Published: May 2018

The simulation of magnetron discharges requires a quantitatively correct mathematical model of the magnetic field structure. This study presents a method to construct such a model on the basis of a spatially restricted set of experimental data and a plausible a priori assumption on the magnetic field configuration. The example in focus is that of a planar circular magnetron. The experimental data are Hall probe measurements of the magnetic flux density in an accessible region above the magnetron plane [P. D. Machura et al., Plasma Sources Sci. Technol. 23, 065043 (2014)]. The a priori assumption reflects the actual design of the device, and it takes the magnetic field emerging from a center magnet of strength mC and vertical position dC and a ring magnet of strength mR, vertical position dR, and radius R. An analytical representation of the assumed field configuration can be formulated in terms of generalized hypergeometric functions. Fitting the ansatz to the experimental data with a least square method results in a fully specified analytical field model that agrees well with the data inside the accessible region and, moreover, is physically plausible in the regions outside of it. The outcome proves superior to the result of an alternative approach which starts from a multimode solution of the vacuum field problem formulated in terms of polar Bessel functions and vertical exponentials. As a first application of the obtained field model, typical electron and ion Larmor radii and the gradient and curvature drift velocities of the electron guiding center are calculated.
Linearly polarized photoluminescence of anisotropically strained c-plane GaN layers on stripe-shaped cavity-engineered sapphire substrate
Authors: Kim Jongmyeong , Moon Daeyoung , Lee Seungmin , Lee Donghyun , Yang Duyoung , Jang Jeonghwan , Park Yongjo , Yoon Euijoon
Published: May 2018

Anisotropic in-plane strain and resultant linearly polarized photoluminescence (PL) of c-plane GaN layers were realized by using a stripe-shaped cavity-engineered sapphire substrate (SCES). High resolution X-ray reciprocal space mapping measurements revealed that the GaN layers on the SCES were under significant anisotropic in-plane strain of −0.0140% and −0.1351% along the directions perpendicular and parallel to the stripe pattern, respectively. The anisotropic in-plane strain in the GaN layers was attributed to the anisotropic strain relaxation due to the anisotropic arrangement of cavity-incorporated membranes. Linearly polarized PL behavior such as the observed angle-dependent shift in PL peak position and intensity comparable with the calculated value based on k·p perturbation theory. It was found that the polarized PL behavior was attributed to the modification of valence band structures induced by anisotropic in-plane strain in the GaN layers on the SCES.
Micromagnetic evaluation of the dissipated heat in cylindrical magnetic nanowires
Authors: Fernandez-Roldan Jose Angel , Serantes David , del Real Rafael P. , Vazquez Manuel , Chubykalo-Fesenko Oksana
Published: May 2018

Magnetic nanowires (NWs) are promising candidates for heat generation under AC-field application due to their large shape anisotropy. They may be used for catalysis, hyperthermia, or water purification treatments. In the present work, we theoretically evaluate the heat dissipated by a single magnetic nanowire, originated from the domain wall (DW) dynamics under the action of an AC-field. We compare the Permalloy NWs (which demagnetize via the transverse wall propagation) with the Co fcc NWs whose reversal mode is via a vortex domain wall. The average hysteresis loop areas—which are proportional to the Specific Absorption Rate (SAR)—as a function of the field frequency have a pronounced maximum in the range 200 MHz–1 GHz. This maximum frequency is smaller in Permalloy than that in Co and depends on the nanowire length. A simple model related to the nucleation and propagation time and DW velocity (higher for the vortex than for the transverse domain wall) is proposed to explain the non-monotonic SAR dependence on the frequency.
A possible structural signature of the onset of cooperativity in metallic liquids
Authors: Dai R. , Ashcraft R. , Kelton K. F.
Published: May 2018

It is widely, although not universally, believed that there must be a connection between liquid dynamics and the structure. Previous supporting studies, for example, have demonstrated a link between the structural evolution in the liquid and kinetic fragility. Here, new results are presented that strengthen the evidence for a connection. By combining the results from high-energy synchrotron X-ray scattering studies of containerlessly processed supercooled liquids with viscosity measurements, an accelerated rate of structural ordering beyond the nearest neighbors in the liquid is demonstrated to correlate with the temperature at which the viscosity transitions from Arrhenius to super-Arrhenius behavior. This is the first confirmation of predictions from several recent molecular dynamics studies.
The maximal negative ion of the time-dependent Thomas-Fermi and the Vlasov atom
Authors: Chen Li , Siedentop Heinz
Published: May 2018

We show that an atom of atomic number Z described by the time-dependent Thomas-Fermi equation or the Vlasov equation cannot bind more than 4Z electrons.
Adsorption of flexible polymer chains on a surface: Effects of different solvent conditions
Authors: Martins P. H. L. , Plascak J. A. , Bachmann M.
Published: May 2018

Polymer chains undergoing a continuous adsorption-desorption transition are studied through extensive computer simulations. A three-dimensional self-avoiding walk lattice model of a polymer chain grafted onto a surface has been treated for different solvent conditions. We have used an advanced contact-density chain-growth algorithm, in which the density of contacts can be directly obtained. From this quantity, the order parameter and its fourth-order Binder cumulant are computed, as well as the corresponding critical exponents and the adsorption-desorption transition temperature. As the number of configurations with a given number of surface contacts and monomer-monomer contacts is independent of the temperature and solvent conditions, it can be easily applied to get results for different solvent parameter values without the need of any extra simulations. In analogy to continuous magnetic phase transitions, finite-size-scaling methods have been employed. Quite good results for the critical properties and phase diagram of very long single polymer chains have been obtained by properly taking into account the effects of corrections to scaling. The study covers all solvent effects, going from the limit of super-self-avoiding walks, characterized by effective monomer-monomer repulsion, to poor solvent conditions that enable the formation of compact polymer structures.
Influence of the aggregate state on band structure and optical properties of C60 computed with different methods
Authors: Pal Amrita , Arabnejad Saeid , Yamashita Koichi , Manzhos Sergei
Published: May 2018

C60 and C60 based molecules are efficient acceptors and electron transport layers for planar perovskite solar cells. While properties of these molecules are well studied by ab initio methods, those of solid C60, specifically its optical absorption properties, are not. We present a combined density functional theory–Density Functional Tight Binding (DFTB) study of the effect of solid state packing on the band structure and optical absorption of C60. The valence and conduction band edge energies of solid C60 differ on the order of 0.1 eV from single molecule frontier orbital energies. We show that calculations of optical properties using linear response time dependent-DFT(B) or the imaginary part of the dielectric constant (dipole approximation) can result in unrealistically large redshifts in the presence of intermolecular interactions compared to available experimental data. We show that optical spectra computed from the frequency-dependent real polarizability can better reproduce the effect of C60 aggregation on optical absorption, specifically with a generalized gradient approximation functional, and may be more suited to study effects of molecular aggregation.
A tungsten-rhenium interatomic potential for point defect studies
Authors: Setyawan Wahyu , Gao Ning , Kurtz Richard J.
Published: May 2018

A tungsten-rhenium (W-Re) classical interatomic potential is developed within the embedded atom method interaction framework. A force-matching method is employed to fit the potential to ab initio forces, energies, and stresses. Simulated annealing is combined with the conjugate gradient technique to search for an optimum potential from over 1000 initial trial sets. The potential is designed for studying point defects in W-Re systems. It gives good predictions of the formation energies of Re defects in W and the binding energies of W self-interstitial clusters with Re. The potential is further evaluated for describing the formation energy of structures in the σ and χ intermetallic phases. The predicted convex-hulls of formation energy are in excellent agreement with ab initio data. In pure Re, the potential can reproduce the formation energies of vacancies and self-interstitial defects sufficiently accurately and gives the correct ground state self-interstitial configuration. Furthermore, by including liquid structures in the fit, the potential yields a Re melting temperature (3130 K) that is close to the experimental value (3459 K).
Argon-plasma-controlled optical reset in the SiO2/Cu filamentary resistive memory stack
Authors: Kawashima T. , Yew K. S. , Zhou Y. , Ang D. S. , Zhang H. Z. , Kyuno K.
Published: May 2018

We show that resistive switching in the SiO2/Cu stack can be modified by a brief exposure of the oxide to an Ar plasma. The set voltage of the SiO2/Cu stack is reduced by 33%, while the breakdown voltage of the SiO2/Si stack (control) is almost unchanged. Besides, the Ar plasma treatment suppresses the negative photoconductivity or optical resistance reset effect, where the electrically formed filamentary conductive path consisting of Cu-ion and oxygen-vacancy clusters is disrupted by the recombination of the oxygen vacancies with nearby light-excited oxygen ions. From the enhanced O-H peak in the Fourier-transform infrared spectrum of the plasma-treated oxide, it is proposed that the Ar plasma has created more oxygen vacancies in the surface region of the oxide. These vacancies in turn adsorb water molecules, which act as counter anions (OH-) promoting the migration of Cu cations into the oxide and forming a more complete Cu filament that is less responsive to light. The finding points to the prospect of a control over the optical resistance reset effect by a simple surface treatment step.