bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural diversity of halocarbonyl molybdenum and tungsten PNP pincer complexes through ligand modifications
Authors: Aguiar Sara R. M. M. de , Stöger Berthold , Pittenauer Ernst , Allmaier Günter , Veiros Luis F. , Kirchner Karl
Published: July 2016

A comparative study of a series of halocarbonyl Mo(ii) and W(ii) complexes featuring PNP pincer ligands based on a 2,6-diaminopyridine scaffold is presented.
Negatively charged Ir(iii) cyclometalated complexes containing a chelating bis-tetrazolato ligand: synthesis, photophysics and the study of reactivity with electrophiles
Authors: Fiorini Valentina , Zacchini Stefano , Raiteri Paolo , Mazzoni Rita , Zanotti Valerio , Massi Massimiliano , Stagni Stefano
Published: July 2016

The synthesis, the reactivity toward electrophiles and use for Ir(iii) based soft salts of new anionic Ir(iii) complexes containing a bis-tetrazolato ligand are described herein.
Giant spin–phonon bottleneck effects in evaporable vanadyl-based molecules with long spin coherence
Authors: Tesi L. , Lunghi A. , Atzori M. , Lucaccini E. , Sorace L. , Totti F. , Sessoli R.
Published: July 2016

The smaller the ligand the slower the low temperature magnetization dynamics of the crystals of vanadyl complexes.
N-Heterocyclic olefins as ancillary ligands in catalysis: a study of their behaviour in transfer hydrogenation reactions
Authors: Iturmendi Amaia , García Nestor , Jaseer E. A. , Munárriz Julen , Sanz Miguel Pablo J. , Polo Victor , Iglesias Manuel , Oro Luis A.
Published: July 2016

Ir(i) complexes featuring an N-heterocyclic olefin ligand (NHO) have been tested in the transfer hydrogenation reaction; this representing the first example of the use of NHOs as ancillary ligands in catalysis.
Mesogenic gold complexes showing aggregation-induced enhancement of phosphorescence in both crystalline and liquid-crystalline phases
Authors: Yamada Shigeyuki , Rokusha Yuki , Kawano Ryo , Fujisawa Kaori , Tsutsumi Osamu
Published: July 2016

Mesogenic Au complexes with a biphenyl core were synthesized as new AIEgens, and their thermodynamic and photophysical properties were discussed. Similar to Au complexes with a phenyl core which have been reported previously, the complexes with a short alkoxy chain formed dimers in the crystal form. However, the complexes with a long alkoxy chain formed two-dimensional layer structures through multiple intermolecular interactions in both the crystalline and liquid-crystalline (LC) phases. The present Au complexes showed a high thermochemical stability against thermal decomposition and a high thermodynamic stability of the LC phase. Moreover, these materials exhibited intensive phosphorescence with a large quantum yield (∼66%) in the crystals. In the crystal and LC phase with a layer structure, the phosphorescence intensity was enhanced only on aggregation. Thus, these mesogenic Au complexes can be expected to be useful as phosphorescent AIEgens.
Real-time assessment of nanoparticle-mediated antigen delivery and cell response
Authors: Cunha-Matos Carlota A. , Millington Owain R. , Wark Alastair W. , Zagnoni Michele
Published: July 2016

Single-cell microfluidics enables real-time monitoring of nanomaterial–cell interaction dynamics.
Biomimetic design of protic lipidic ionic liquids with enhanced fluidity
Authors: O'Brien Richard A. , Zayas Manuel Sanchez , Nestor Stephen T. , Gaitor Jamie C. , Paul Lauran M. , Edhegard Forrest A. , Minkowicz Samuel , Sykora Richard E. , Sheng Yinghong , Michael Scott F. , Isern Sharon , Mirjafari Arsalan
Published: July 2016

Synthesis of low-melting protic ionic liquids with C16–C20 side chains via the S-alkylation of the methimazole ring.
Organoselenium-catalyzed vicinal dichlorination of unsaturated phosphonates
Authors: Zeng Xianghua , Gong Chunhua , Zhang Junyong , Xie Jingli
Published: July 2016

An efficient organoselenium-catalyzed vicinal dichlorination of unsaturated phosphonates was developed under mild conditions.
Selective glucose conversion to 5-hydroxymethylfurfural (5-HMF) instead of levulinic acid with MIL-101Cr MOF-derivatives
Authors: Herbst Annika , Janiak Christoph
Published: July 2016

MOFs are also making progress in catalytic biomass transformation, here in the 5-HMF production with increased yield from glucose in low boiling solvents.
Native and engineered promoters in natural product discovery
Authors: Myronovskyi Maksym , Luzhetskyy Andriy
Published: July 2016

Transcriptional activation of biosynthetic gene clusters.
Biotinylated carboxymethyl chitosan/CaCO3 hybrid nanoparticles for targeted drug delivery to overcome tumor drug resistance
Authors: Wu Jin-Long , He Xiao-Yan , Jiang Pei-Yuan , Gong Meng-Qing , Zhuo Ren-Xi , Cheng Si-Xue
Published: July 2016

A tumor targeted nano-sized self-assembled drug delivery system could efficiently co-deliver an anti-cancer drug and a drug resistance inhibitor to tumor cells and achieve an improved therapeutic efficiency through inhibition of P-gp function.
Preparation of pharmaceutical co-crystals through sustainable processes using supercritical carbon dioxide: a review
Authors: Pando Concepción , Cabañas Albertina , Cuadra Isaac A.
Published: July 2016

The preparation of pharmaceutical co-crystals using supercritical CO2 (scCO2) is reviewed.
Photoisomerization and optical properties of a subphthalocyanine–azobenzene–subphthalocyanine triad
Authors: Shi Maohu , Zhao Yue , Xu Haijun , Mack John , Yin Luan , Wang Xiaoyong , Shen Zhen
Published: July 2016

A novel subPc–AB–subPc triad exhibits on–off switching of the fluorescence emission intensity upon reversible trans ↔ cis photoisomerization of the azobenzene moiety. NMR spectroscopy provides additional evidence for the conformational change.
What determines the volume transition temperature of UCST acrylamide–acrylonitrile hydrogels?
Authors: Augé Amélie , Zhao Yue
Published: July 2016

The positive thermosensitivity of a hydrogel composed of acrylamide and acrylonitrile was investigated, and the parameters that determine the hydrogel's volume transition temperature were identified.
Synthesis of silsesquioxane-based element-block amphiphiles and their self-assembly in water
Authors: Yusa S. , Ohno S. , Honda T. , Imoto H. , Nakao Y. , Naka K. , Nakamura Y. , Fujii S.
Published: July 2016

The self-assembly of silsesquioxane-based amphiphiles in water was investigated.
Investigation on polyvinyl-alcohol-based rapidly gelling hydrogels for containment of hazardous chemicals
Authors: Yuan Le , Ren Lijun , Tian Xingtao , Huang Zhiping , Xiao YanHua , Wei Sichen , Wang Zhihua
Published: July 2016

PVA-based rapidly gelling hydrogels were prepared in situ for the containment of hazardous chemicals.
Efficient perovskite light-emitting diodes by film annealing temperature control
Authors: Liang Junqing , Zhang Yongqiang , Guo Xiaoyang , Gan Zhihong , Lin Jie , Fan Yi , Liu Xingyuan
Published: July 2016

A bright perovskite light-emitting diode has been fabricated through film annealing temperature control.
Analysis of contact area between water and irregular fibrous surface for prediction of wettability
Authors: Yuan Yue , Choi Seong-O , Kim Jooyoun
Published: July 2016

A characterization method was developed, which visualizes the wetted solid area fraction (fs) of the Cassie–Baxter model on a roughened surface.
Temperature dependent solubility of gold nanoparticle suspension/solutions
Authors: Powell J. A. , Schwieters R. M. , Bayliff K. W. , Herman E. N. , Hotvedt N. J. , Changstrom J. R. , Chakrabarti A. , Sorensen C. M.
Published: July 2016

We present measurements of the temperature dependence of thermally reversible solubility for a nanoparticle (NP) suspension/solution.
N-heterocyclic carbene induced reductive coupling of phosphorus tribromide. Isolation of a bromine bridged P–P bond and its subsequent reactivity
Authors: Waters Jordan B. , Everitt Thomas A. , Myers William K. , Goicoechea Jose M.
Published: July 2016

Thermal treatment of a 1:1 adduct of phosphorus tribromide and 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene (IPr) results in the formation of a reduced phosphorus-containing dimer, which can be employed to access a range of low oxidation state compounds.
Unexpected highly reversible topotactic CO2 sorption/desorption capacity for potassium dititanate
Authors: Zheng Qianwen , Huang Liang , Zhang Yu , Wang Junya , Zhao Chen-Zi , Zhang Qiang , Zheng Weijie , Cao Dapeng , O'Hare Dermot , Wang Qiang
Published: July 2016

Potassium dititanate (K2Ti2O5) was revealed to possess an unexpected, highly reversible CO2 sorption/desorption capacity at ca. 750 °C, which is promising as a high-temperature CO2 adsorbent for sorption enhanced hydrogen production (SEHP) processes.
Effect of an auxiliary acceptor on D–A–π–A sensitizers for highly efficient and stable dye-sensitized solar cells
Authors: Gao Yuting , Li Xing , Hu Yue , Fan Yeli , Yuan Jianyong , Robertson Neil , Hua Jianli , Marder Seth R.
Published: July 2016

As one of the promising photovoltaic technologies, high performance metal-free dye-sensitized solar cells (DSSCs) have been explored due to the fact that they can be potentially produced using low-cost materials, their color can be tuned and they exhibit reasonable stability.
One-step synthesis of glycoprotein mimics in vitro: improvement of protein activity, stability and application in CPP hydrolysis
Authors: Cui Yuecheng , Li Zhenhua , Wang Lei , Liu Feng , Yuan Yuqi , Wang Hongwei , Xue Lulu , Pan Jingjing , Chen Gaojian , Chen Hong , Yuan Lin
Published: July 2016

Glycoprotein mimics producedin vitroby one-step conjugation of glycopolymer and pyrophosphatase have improved bioactivity and stability for potential biomedical applications.
Fourfold in-plane magnetic anisotropy of magnetite thin films grown on TiN buffered Si(001) by ion-assisted sputtering
Authors: Prieto Pilar , de la Figuera Juan , Martín-García Laura , Prieto José Emilio , Marco José F.
Published: July 2016

Fourfold in-plane magnetic anisotropy observed in stoichiometric and nonstoichiometric magnetite thin films grown on TiN buffered Si(001), which is relevant for their incorporation in devices.
SLM localised SC‐FDMA performance evaluation based on 30 GHz channel measurement for 5G
Authors: Khelil A. , Slimani D. , Talbi L. , LeBel J.
Published: July 2016

A performance evaluation of selective mapping localised single carrier frequency division multiple access technique (SLM LSC‐FDMA) is presented over channel measured at 30 GHz. These measurements were taken between three buildings under non‐line‐of‐sight (NLOS) for a propagation path length of 183 m. Simulation results present a peak‐to‐average power ratio gain of 3.78 dB for the proposed scheme over localised orthogonal frequency division multiple access system and an acceptable bit error rate with and without high power amplifier compared with LSC‐FDMA. These results show an improvement of the transmission efficiency under NLOS outdoor scenario at 30 GHz. Hence, these results suggest the use of SLM LSC‐FDMA wave form for fifth generation mobile communication at 30 GHz.
Integrated modelling of medical emergency response process for improved coordination and decision support
Authors: Milis George , Kolios Panayiotis , Van Melick Gaby , Staykova Toni , Helsloot Ira , Ellinas Georgios , Panayiotou Christos , Polycarpou Marios
Published: July 2016

The medical emergency response comprises a domain with complex processes, encompassing multiple heterogeneous entities, from organisations involved in the response to human actors to key information sources. Due to the heterogeneity of the entities and the complexity of the domain, it is important to fully understand the individual processes in which the components are involved and their inter‐operations, before attempting to design any technological tool for coordination and decision support. This work starts with the gluing together and visualisation of the interactions of involved entities into a conceptual model, along the identified five workspaces of emergency response. The modelling visualises the domain processes, in a way that reveals the necessary communication and coordination points, the required data sources and data flows, as well as the required decision support needs. Work continues with the identification and modelling of the event‐driven discrete‐time‐based dynamics of the emergency response processes and their compositions, using Petri nets as the modelling technique. Subsequently, an integrated model of the process is presented, which facilitates the parallelisation of the tasks undertaken in an emergency incident.
High‐performing orthogonal frequency division multiplexing precoding scheme for OOBE suppression
Authors: You Zihao , Lu I‐Tai , Li Wenhao
Published: July 2016

Presented in this study is a novel precoding scheme for orthogonal frequency division multiplexing systems to suppress the out‐of‐band emission (OOBE). The scheme suppresses the OOBE by making the transmitted signal satisfy the continuous derivative property and the notched frequency (NF) property, which have been proposed separately in some existing schemes. Unlike most of the continuous derivative related schemes that require iterative decoders, authors’ scheme employs a non‐iterative decoder. Numerical results show that their proposed scheme achieves superior OOBE suppression than the other non‐iterative continuous derivative precoding schemes and NF schemes. Computational complexity, peak‐to‐average power ratio, and bit error rate are also analysed.
Coverage improvement in femtocell networks via efficient utility pricing
Authors: Shafiei‐Kordshouli Maryam , Zeinalpour‐Yazdi Zolfa , Ramezanian Rasoul
Published: July 2016

Employing femtocell technology noticeably improves both the indoor coverage and the overall cellular network's capacity. In the downlink scenario, when macrocell users (MUs) are far from the macro base station (MBS) and close to the femto access points (FAPs), the transmitted signals of FAPs to their users cause severe interference on MUs. One solution to overcome this issue is serving MUs by neighbouring FAPs. Generally femtocells are selfish and have no desire to allocate their resources to MUs. In this study, a framework to motivate femtocells to share their free resources with MUs is proposed. In this framework, the femtocells are assumed to belong to a specific unit. The unit encourages and manages the femtocells to share their resources, and in exchange receives a monetary utility from the MBS, and as a result improves the performance of the network. A computationally‐efficient algorithm is proposed, which approximates the complete search algorithm, and their solutions coincide with each other in many cases. After FAPs assignment, the authors try to allocate the optimal power to MUs served by each femtocell to further improve their coverage probability through a bargaining game. The simulation results verify the performance of the proposed model and confirm the coverage improvement obtained in the network.
Rateless space–time block code for mitigating pilot contamination effects in multi‐cell massive MIMO system with lossy links
Authors: Alqahtani Ali H. , Sulyman Ahmed Iyanda , Alsanie Abdulhameed
Published: July 2016

Massive multiple‐input multiple‐output (MIMO) is a breakthrough wireless transmission technique proposed for future wireless standards due to its spectrum and energy efficiencies. However, pilot contamination constitutes a particularly significant impairment in multi‐cell systems that utilise reciprocity‐based channel estimation. This phenomenon results from the non‐orthogonality of the pilot sequences in different cells. Given a large number of antennas employed in massive MIMO systems, conventional channel estimation schemes cannot mitigate this problem effectively without high computational complexity. In this study, a simple rateless space–time block code (RSTBC) is employed in the downlink transmission of a lossy multi‐cell massive MIMO system to mitigate the effects of signal‐to‐interference‐and‐noise ratio (SINR) degradation resulting from pilot contamination. Specifically, a robust optimisation problem is formulated to maximise the minimum downlink SINR among all users. Simulation and analytical results for large numbers of antenna elements at the base station (BS) are provided to demonstrate the usefulness of the proposed scheme. The SINR and spectral efficiency analyses indicate that RSTBC can effectively mitigate downlink SINR degradation that is caused by pilot contamination. Experimental results for the proposed scheme are also included for a 2 × 2 MIMO system, and it agrees closely with the simulation.
Improving physical layer security in untrusted relay networks: cooperative jamming and power allocation
Authors: Lv Lu , Chen Jian , Yang Long , Kuo Yonghong
Published: July 2016

The inherent broadcast characteristics of wireless medium make wireless data transmission difficult to be shielded from unintended recipients. As such, secure communication over wireless channels becomes a critical issue in the design of wireless networks. In this study, the authors study cooperative jamming and power optimisation in untrusted relay networks to improve physical layer security. By exploiting the direct link, a source‐based jamming (SBJ) scheme is proposed to hinder the untrusted relay from intercepting the confidential message. Considering the total power budget, a power allocation strategy is also proposed to optimally determine the power of source and untrusted relay as well as the power of information and jamming signals. Furthermore, to evaluate the secrecy performance of the proposed SBJ scheme with the power allocation strategy, tight lower bound of ergodic secrecy capacity and asymptotic secrecy outage probability are derived in closed form. Simulation verifies the advantages of the proposed SBJ scheme and the power allocation strategy.
Decentralised control method for DC microgrids with improved current sharing accuracy
Authors: Yang Jie , Jin Xinmin , Wu Xuezhi , Acuna Pablo , Aguilera Ricardo P. , Morstyn Thomas , Agelidis Vassilios G.
Published: July 2016

A decentralised control method that deals with current sharing issues in dc microgrids (MGs) is proposed in this study. The proposed method is formulated in terms of ‘modified global indicator’ concept, which was originally proposed to improve reactive power sharing in ac MGs. In this work, the ‘modified global indicator’ concept is extended to coordinate dc MGs, which aims to preserve the main features offered by decentralised control methods such as no need of communication links, central controller or knowledge of the microgrid topology and parameters. This global indicator is inserted between current and voltage variables by adopting a virtual capacitor, which directly produces an output current sharing performance that is less relied on mismatches of the multi‐bus network. Meanwhile, a voltage stabiliser is complementary developed to maintain output voltage magnitude at steady state through a shunt virtual resistance. The operation under multiple dc‐buses is also included in order to enhance the applicability of the proposed controller. A detailed mathematical model including the effect of network mismatches is derived for analysis of the stability of the proposed controller. The feasibility and effectiveness of the proposed control strategy are validated by simulation and experimental results.
Bi-directional conversion between microwave and optical frequencies in a piezoelectric optomechanical device
Authors: Vainsencher Amit , Satzinger K. J. , Peairs G. A. , Cleland A. N.
Published: July 2016

We describe the principles of design, fabrication, and operation of a piezoelectric optomechanical crystal with which we demonstrate bi-directional conversion of energy between microwave and optical frequencies. The optomechanical crystal has an optical mode at 1523 nm co-located with a mechanical breathing mode at 3.8 GHz, with a measured optomechanical coupling strength gom/2π of 115 kHz. The breathing mode is driven and detected by curved interdigitated transducers that couple to a Lamb mode in suspended membranes on either end of the optomechanical crystal, allowing the external piezoelectric modulation of the optical signal as well as the converse, the detection of microwave electrical signals generated by a modulated optical signal. We compare measurements to theory where appropriate.
The QTP family of consistent functionals and potentials in Kohn-Sham density functional theory
Authors: Jin Yifan , Bartlett Rodney J.
Published: July 2016

This manuscript presents the second, consistent density functional in the QTP (Quantum Theory Project) family, that is, the CAM-QTP(01). It is a new range-separated exchange-correlation functional in which the non-local exchange contribution is 100% at large separation. It follows the same basic principles of this family that the Kohn-Sham eigenvalues of the occupied orbitals approximately equal the vertical ionization energies, which is not fulfilled by most of the traditional density functional methods. This new CAM-QTP(01) functional significantly improves the accuracy of the vertical excitation energies especially for the Rydberg states in the test set. It also reproduces many other properties such as geometries, reaction barrier heights, and atomization energies.
Spin relaxation of radicals in cryptochrome and its role in avian magnetoreception
Authors: Worster Susannah , Kattnig Daniel R. , Hore P. J.
Published: July 2016

Long-lived spin coherence and rotationally ordered radical pairs have previously been identified as key requirements for the radical pair mechanism of the avian magnetic compass sense. Both criteria are hard to meet in a biological environment, where thermal motion of the radicals creates dynamic disorder and drives efficient spin relaxation. This has long been cited as a major stumbling block of the radical pair hypothesis. Here we combine Redfield relaxation theory with analytical solutions to a rotational diffusion equation to assess the impact of restricted rotational motion of the radicals on the operation of the compass. The effects of such motions are first investigated generally in small, model systems and are then critically examined in the magnetically sensitive flavin-tryptophan radical pair that is formed photochemically in the proposed magnetoreceptor protein, cryptochrome. We conclude that relaxation is slowest when rotational motion of the radicals within the protein is fast and highly constrained; that in a regime of slow relaxation, the motional averaging of hyperfine interactions has the potential to improve the sensitivity of the compass; and that consideration of motional effects can significantly alter the design criteria for an optimal compass. In addition, we demonstrate that motion of the flavin radical is likely to be compatible with its role as a component of a functioning radical-pair compass, whereas the motion of the tryptophan radical is less ideal, unless it is particularly fast.
Coarse-grained models using local-density potentials optimized with the relative entropy: Application to implicit solvation
Authors: Sanyal Tanmoy , Shell M. Scott
Published: July 2016

Bottom-up multiscale techniques are frequently used to develop coarse-grained (CG) models for simulations at extended length and time scales but are often limited by a compromise between computational efficiency and accuracy. The conventional approach to CG nonbonded interactions uses pair potentials which, while computationally efficient, can neglect the inherently multibody contributions of the local environment of a site to its energy, due to degrees of freedom that were coarse-grained out. This effect often causes the CG potential to depend strongly on the overall system density, composition, or other properties, which limits its transferability to states other than the one at which it was parameterized. Here, we propose to incorporate multibody effects into CG potentials through additional nonbonded terms, beyond pair interactions, that depend in a mean-field manner on local densities of different atomic species. This approach is analogous to embedded atom and bond-order models that seek to capture multibody electronic effects in metallic systems. We show that the relative entropy coarse-graining framework offers a systematic route to parameterizing such local density potentials. We then characterize this approach in the development of implicit solvation strategies for interactions between model hydrophobes in an aqueous environment.
3D printing of gas jet nozzles for laser-plasma accelerators
Authors: Döpp A. , Guillaume E. , Thaury C. , Gautier J. , Ta Phuoc K. , Malka V.
Published: July 2016

Recent results on laser wakefield acceleration in tailored plasma channels have underlined the importance of controlling the density profile of the gas target. In particular, it was reported that the appropriate density tailoring can result in improved injection, acceleration, and collimation of laser-accelerated electron beams. To achieve such profiles, innovative target designs are required. For this purpose, we have reviewed the usage of additive layer manufacturing, commonly known as 3D printing, in order to produce gas jet nozzles. Notably we have compared the performance of two industry standard techniques, namely, selective laser sintering (SLS) and stereolithography (SLA). Furthermore we have used the common fused deposition modeling to reproduce basic gas jet designs and used SLA and SLS for more sophisticated nozzle designs. The nozzles are characterized interferometrically and used for electron acceleration experiments with the Salle Jaune terawatt laser at Laboratoire d’Optique Appliquée.
Development of a fluorescence based flux sensor for thin film growth and nanoparticle deposition
Authors: De Roo Bert , Vervaele Mattias , Rajala Markku , Miller Toni , Guillon Herve , Seo Jin Won , Locquet Jean-Pierre
Published: July 2016

An optical flux sensor, based on the fluorescence properties of materials and nanoparticles, has been developed to control the deposition rate in thin film deposition systems. Using a simple diode laser and a photomultiplier tube with a light filter, we report the detection of gallium atoms and CdSe-ZnS quantum dots. This setup has a high sensitivity and reproducibility.
Observation of thermally driven field-like spin torque in magnetic tunnel junctions
Authors: Bose Arnab , Shukla Amit Kumar , Konishi Katsunori , Jain Sourabh , Asam Nagarjuna , Bhuktare Swapnil , Singh Hanuman , Lam Duc Duong , Fujii Yuya , Miwa Shinji , Suzuki Yoshishige , Tulapurkar Ashwin A.
Published: July 2016

We report the thermally driven giant field-like spin-torque in magnetic tunnel junctions (MTJ) on application of heat current from top to bottom. The field-like term is detected by the shift of the magneto-resistance hysteresis loop applying temperature gradient. We observed that the field-like term depends on the magnetic symmetry of the MTJ. In asymmetric structures, with different ferromagnetic materials for free and fixed layers, the field-like term is greatly enhanced. Our results show that a pure spin current density of the order of 109 A/m2 can be produced by creating a 120 mK temperature difference across 0.9 nm thick MgO tunnelling barrier. Our results will be useful for writing MTJ and domain wall-based memories using thermally driven spin torque.
Effects of antimony (Sb) on electron trapping near SiO2/4H-SiC interfaces
Authors: Mooney P. M. , Jiang Zenan , Basile A. F. , Zheng Yongju , Dhar Sarit
Published: July 2016

To investigate the mechanism by which Sb at the SiO2/SiC interface improves the channel mobility of 4H-SiC MOSFETs, 1 MHz capacitance measurements and constant capacitance deep level transient spectroscopy (CCDLTS) measurements were performed on Sb-implanted 4H-SiC MOS capacitors. The measurements reveal a significant concentration of Sb donors near the SiO2/SiC interface. Two Sb donor related CCDLTS peaks corresponding to shallow energy levels in SiC were observed close to the SiO2/SiC interface. Furthermore, CCDLTS measurements show that the same type of near-interface traps found in conventional dry oxide or NO-annealed capacitors are present in the Sb implanted samples. These are O1 traps, suggested to be carbon dimers substituted for O dimers in SiO2, and O2 traps, suggested to be interstitial Si in SiO2. However, electron trapping is reduced by a factor of ∼2 in Sb-implanted samples compared with samples with no Sb, primarily at energy levels within 0.2 eV of the SiC conduction band edge. This trap passivation effect is relatively small compared with the Sb-induced counter-doping effect on the MOSFET channel surface, which results in improved channel transport.
Application of the coincidence counting technique to DD neutron spectrometry data at the NIF, OMEGA, and Z
Authors: Lahmann B. , Milanese L. M. , Han W. , Gatu Johnson M. , Séguin F. H. , Frenje J. A. , Petrasso R. D. , Hahn K. D. , Jones B.
Published: July 2016

A compact neutron spectrometer, based on a CH foil for the production of recoil protons and CR-39 detection, is being developed for the measurements of the DD-neutron spectrum at the NIF, OMEGA, and Z facilities. As a CR-39 detector will be used in the spectrometer, the principal sources of background are neutron-induced tracks and intrinsic tracks (defects in the CR-39). To reject the background to the required level for measurements of the down-scattered and primary DD-neutron components in the spectrum, the Coincidence Counting Technique (CCT) must be applied to the data. Using a piece of CR-39 exposed to 2.5-MeV protons at the MIT HEDP accelerator facility and DD-neutrons at Z, a significant improvement of a DD-neutron signal-to-background level has been demonstrated for the first time using the CCT. These results are in excellent agreement with previous work applied to DT neutrons.
Generation of 2N + 1-scroll existence in new three-dimensional chaos systems
Authors: Liu Yue , Guan Jian , Ma Chunyang , Guo Shuxu
Published: July 2016

We propose a systematic methodology for creating 2N + 1-scroll chaotic attractors from a simple three-dimensional system, which is named as the translation chaotic system. It satisfies the condition a12a21 = 0, while the Chua system satisfies a12a21 > 0. In this paper, we also propose a successful (an effective) design and an analytical approach for constructing 2N + 1-scrolls, the translation transformation principle. Also, the dynamics properties of the system are studied in detail. MATLAB simulation results show very sophisticated dynamical behaviors and unique chaotic behaviors of the system. It provides a new approach for 2N + 1-scroll attractors. Finally, to explore the potential use in technological applications, a novel block circuit diagram is also designed for the hardware implementation of 1-, 3-, 5-, and 7-scroll attractors via switching the switches. Translation chaotic system has the merit of convenience and high sensitivity to initial values, emerging potentials in future engineering chaos design.
Thin film versus paper-like reduced graphene oxide: Comparative study of structural, electrical, and thermoelectrical properties
Authors: Okhay Olena , Gonçalves Gil , Tkach Alexander , Dias Catarina , Ventura Joao , Ribeiro da Silva Manuel Fernando , Valente Gonçalves Luís Miguel , Titus Elby
Published: July 2016

We report fabrication of reduced graphene oxide (rGO) films using chemical reduction by hydrazine hydrate and rGO paper-like samples using low temperature treatment reduction. Structural analysis confirms the formation of the rGO structure for both samples. Current-voltage (I–V) measurements of the rGO film reveal semiconductor behavior with the maximum current value of ∼3 × 10−4A. The current for the rGO paper sample is found to be, at least, one order of magnitude higher. Moreover, bipolar resistance switching, corresponding to memristive behavior of type II, is observed in the I–V data of the rGO paper. Although precise values of the rGO film conductivity and the Seebeck coefficient could not be measured, rGO paper shows an electrical conductivity of 6.7 × 102 S/m and Seebeck coefficient of −6 μV/ °C. Thus, we demonstrate a simplified way for the fabrication of rGO paper that possesses better and easier measurable macroscopic electrical properties than that of rGO thin film.
Structural and optical properties of silicon rich oxide films in graded-stoichiometric multilayers for optoelectronic devices
Authors: Palacios-Huerta L. , Cabañas-Tay S. A. , Cardona-Castro M. A. , Aceves-Mijares M. , Domínguez-Horna C. , Morales-Sánchez A.
Published: July 2016

Silicon nanocrystals (Si-ncs) are excellent candidates for the development of optoelectronic devices. Nevertheless, different strategies are still necessary to enhance their photo and electroluminescent properties by controlling their structural and compositional properties. In this work, the effect of the stoichiometry and structure on the optical properties of silicon rich oxide (SRO) films in a multilayered (ML) structure is studied. SRO MLs with silicon excess gradually increased towards the top and bottom and towards the center of the ML produced through the variation of the stoichiometry in each SRO layer were fabricated and confirmed by X-ray photoelectron spectroscopy. Si-ncs with three main sizes were observed by a transmission electron microscope, in agreement with the stoichiometric profile of each SRO layer. The presence of the three sized Si-ncs and some oxygen related defects enhances intense violet/blue and red photoluminescence (PL) bands. The SRO MLs were super-enriched with additional excess silicon by Si+ implantation, which enhanced the PL intensity. Oxygen-related defects and small Si-ncs (<2 nm) are mostly generated during ion implantation enhancing the violet/blue band to become comparable to the red band. The structural, compositional, and luminescent characteristics of the multilayers are the result of the contribution of the individual characteristics of each layer.
Carrier dynamics and Coulomb-enhanced capture in III-nitride quantum heterostructures
Authors: David Aurelien , Hurni Christophe A. , Young Nathan G. , Craven Michael D.
Published: July 2016

A detailed study of the small-signal response of III-Nitride quantum well (QW) light-emitting diodes is presented, in which the electrical and optical responses are simultaneously measured. A complete transport-recombination model is introduced to account for measurements. This allows for a proper evaluation of the recombination lifetime and for the accurate quantification of thermionic carrier escape from the QW. Further, a yet-unreported carrier capture mechanism is identified and quantified; it increases with the carrier density in the QW and bears the signature of a Coulomb in-scattering process.
A broadband bi-stable flow energy harvester based on the wake-galloping phenomenon
Authors: Alhadidi A. H. , Daqaq M. F.
Published: July 2016

Linear wake-galloping flow energy harvesters have a narrow frequency bandwidth restricted to the lock-in region, where the vortex shedding frequency is close to the natural frequency of the harvester. As a result, their performance is very sensitive to variations in the flow speed around the nominal design value. This letter demonstrates that the lock-in region of a wake-galloping flow energy harvester can be improved by exploiting a bi-stable restoring force. To demonstrate the enhanced performance, the response behavior of a bi-stable piezoelectric cantilever harvester is evaluated in a wind tunnel. A Von Kármán vortex street is generated by placing a rectangular rod in the windward direction of the harvester and the voltage response of the harvester is evaluated as a function of the wind speed. It is shown that, compared to the linear design, bi-stability can be used to improve the steady-state bandwidth considerably.
Metal-nanotube composites as radiation resistant materials
Authors: González Rafael I. , Valencia Felipe , Mella José , van Duin Adri C. T. , So Kang Pyo , Li Ju , Kiwi Miguel , Bringa Eduardo M.
Published: July 2016

The improvement of radiation resistance in nanocomposite materials is investigated by means of classical reactive molecular dynamics simulations. In particular, we study the influence of carbon nanotubes (CNTs) in an Ni matrix on the trapping and possible outgassing of He. When CNTs are defect-free, He atoms diffuse alongside CNT walls and, although there is He accumulation at the metal-CNT interface, no He trespassing of the CNT wall is observed, which is consistent with the lack of permeability of a perfect graphene sheet. However, when vacancies are introduced to mimic radiation-induced defects, He atoms penetrate CNTs, which play the role of nano-chimneys, allowing He atoms to escape the damaged zone and reduce bubble formation in the matrix. Consequently, composites made of CNTs inside metals are likely to display improved radiation resistance, particularly when radiation damage is related to swelling and He-induced embrittlement.
Equivalent circuit representation of hysteresis in solar cells that considers interface charge accumulation: Potential cause of hysteresis in perovskite solar cells
Authors: Seki Kazuhiko
Published: July 2016

If charge carriers accumulate in the charge transport layer of a solar cell, then the transient response of the electric field that originates from these accumulated charges results in hysteresis in the current-voltage (J-V) characteristics. While this mechanism was previously known, a theoretical model to explain these J-V characteristics has not been considered to date. We derived an equivalent circuit from the proposed hysteresis mechanism. By solving the equivalent circuit model, we were able to reproduce some of the features of hysteresis in perovskite solar cells.
Organic-inorganic proximity effect in the magneto-conductance of vertical organic field effect transistors
Authors: Khachatryan B. , Greenman M. , Devir-Wolfman A. H. , Tessler N. , Ehrenfreund E.
Published: July 2016

Vertical organic field effect transistors having a patterned source electrode and an a-SiO2 insulation layer show high performance as a switching element with high transfer characteristics. By measuring the low field magneto-conductance under ambient conditions at room temperature, we show here that the proximity of the inorganic a-SiO2 insulation to the organic conducting channel affects considerably the magnetic response. We propose that in n-type devices, electrons in the organic conducting channel and spin bearing charged defects in the inorganic a-SiO2 insulation layer (e.g., O2 = Si+·) form oppositely charged spin pairs whose singlet-triplet spin configurations are mixed through the relatively strong hyperfine field of 29Si. By increasing the contact area between the insulation layer and the conducting channel, the ∼2% magneto-conductance response may be considerably enhanced.
Temperature induced complementary switching in titanium oxide resistive random access memory
Authors: Panda D. , Simanjuntak F. M. , Tseng T.-Y.
Published: July 2016

On the way towards high memory density and computer performance, a considerable development in energy efficiency represents the foremost aspiration in future information technology. Complementary resistive switch consists of two antiserial resistive switching memory (RRAM) elements and allows for the construction of large passive crossbar arrays by solving the sneak path problem in combination with a drastic reduction of the power consumption. Here we present a titanium oxide based complementary RRAM (CRRAM) device with Pt top and TiN bottom electrode. A subsequent post metal annealing at 400°C induces CRRAM. Forming voltage of 4.3 V is required for this device to initiate switching process. The same device also exhibiting bipolar switching at lower compliance current, Ic <50 μA. The CRRAM device have high reliabilities. Formation of intermediate titanium oxi-nitride layer is confirmed from the cross-sectional HRTEM analysis. The origin of complementary switching mechanism have been discussed with AES, HRTEM analysis and schematic diagram. This paper provides valuable data along with analysis on the origin of CRRAM for the application in nanoscale devices.
Assessing sea level-rise risks to coastal floodplains in the Kakadu Region, northern Australia, using a tidally driven hydrodynamic model
Authors: Bayliss Peter , Saunders Kate , Dutra Leo X. C. , Melo Lizandra F. C. , Hilton James , Prakash Mahesh , Woolard Fletcher
Published: July 2016

The low-lying coastal floodplains of the Kakadu Region in tropical northern Australia encompass World Heritage Kakadu National Park and are highly vulnerable to future sea level-rise (SLR) and extreme weather events, yet there are no modelling tools to assess potential impacts of saltwater inundation (SWI) on freshwater ecosystems and to evaluate future management options. A tidally driven hydrodynamic model was developed to simulate the frequency and extent of SWI in the Kakadu Region for the following four mean SLR scenarios: 0m (present-day, 2013); 0.14m (2030); 0.70m (2070); and 1.1m (2100). Simulations were undertaken at 60-m spatial resolution using October dry-season tides, and a digital elevation model (0.10-m vertical resolution) constructed from LiDAR point cloud data was used to resolve coastal and river-system terrains. Model outputs (maximum extent and frequency of SWI) were used to assess potential loss of freshwater floodplains for each scenario at a park-wide scale and for three case-study areas that differ in tidal influence. Results show little loss by 2030 (–3%), a possible threshold effect by 2070 (–42%) and ameliorating after 2100 (–65%). Although freshwater floodplains further from the coast showed least exposure to simulated SLR, indicating potential refuge areas, all floodplains on Kakadu will be exposed to SWI by 2132 (+117 years).
Dietary selection by goats and the implications for range management in the Chihuahuan Desert: a review
Authors: Mellado M.
Published: July 2016

Field studies characterising the forage resources of mixed-breed goats on Chihuahuan Desert rangelands were reviewed and the principal sources of variation in their diet choices discussed. Goats eat a varied diet comprising at least 126 plant species in this landscape. Goats are highly selective feeders, changing their diet from predominantly forbs (8–64%) to browse (35–88%). Graminoids make up only ~5% of the diet, but grasses could be important dietary components on rangelands in good condition. Feed intakes range between 0.8% and 3.4% of bodyweight, depending on the season. DM digestibility of forage selected by goats ranges between 44% and 65%. Annual crude protein (CP) in forages selected by goats varies from 80 to 160 g CP kg–1 DM. Overall, pregnant and lactating goats manage to ingest food that contains higher amounts of CP and lower amounts of cell wall than non-pregnant, non-lactating goats. Goats not adapted to severe shortage of forage select a diet that does not match their nutritional requirements and fetal losses occur. Goat kids select higher quality diets than do mature goats (94.5 vs 88.5 g CP kg–1 DM). Granadina goats eat ~20% more shrubs, including 3-fold more Larrea tridentata (DC) Cav., than Nubian goats. Goats with severely eroded incisors avoid grasses, focusing on tender-leaved shrubs. During the rainy season, bucks select mainly shrubs (78% of the diet) and avoid grasses (1.7% of the diet), whereas does rely heavily on forbs (about one-third of their diet). Alternating use of grazing grounds increases shrub ingestion by 25%. No evidence exists indicating that food choice by goats in this arid environment is biased towards forages with lower secondary compounds. It is concluded that the flexible, broad-scale and opportunistic feeding behaviour of goats make them an effective animal to sustainably exploit the forage resources of the Chihuahuan Desert.
Extending experiences of voluntary action by association
Authors: Khalighinejad Nima , Haggard Patrick
Published: July 2016

Significance

In everyday life, people feel in control of their voluntary actions and their outcomes. This “sense of agency” could reflect hard-wired brain signals for volition, or could be acquired by repeated association between a goal-directed action and another event. By pairing voluntary actions of one hand with involuntary movements of the other hand, we showed that key aspects of agency experience can transfer from voluntary to involuntary movements. Our results explain why one can feel fully in control of one’s actions even when they are performed automatically, without focal conscious attention. We suggest that sense of agency depends on a metacognitive signal that is relatively nonspecific. Our findings could guide acquisition of voluntary control using neuroprosthetics and brain–machine interfaces.
Saturation scanning of ubiquitin variants reveals a common hot spot for binding to USP2 and USP21
Authors: Leung Isabel , Dekel Ayelet , Shifman Julia M. , Sidhu Sachdev S.
Published: July 2016

Significance

Although ubiquitin (Ub) interactions are essential to cell physiology, there is a paucity of functional data on how Ub recognizes the diverse enzymes in the Ub proteasome system. We subjected two high-affinity Ub variants (Ubvs) to saturation scanning analysis to obtain comprehensive information on how they interact with Ub-specific proteases (USPs). Our data reveal the molecular details of how individual Ubv side chains mediate weak but specific interactions with these proteases. We find that the enzymes are recognized by similar functional epitopes on the Ubvs, and that these epitopes interact with a region that is conserved across the human USP family, suggesting that Ub may interact with many USPs by using a common core functional epitope.
Are the surface Fermi arcs in Dirac semimetals topologically protected?
Authors: Kargarian Mehdi , Randeria Mohit , Lu Yuan-Ming
Published: July 2016

Significance

In recent years there has been a surge of interest in quantum materials with topologically protected properties that are robust against the effects of disorder and other perturbations. An interesting example is the newly discovered three-dimensional analog of graphene, called Dirac semimetals. These were expected to have highly unusual conducting states on their surfaces. We show here that the surface states of Dirac semimetals do not exhibit the expected topological robustness and, quite generally, get deformed into states that are of a rather different character. Our theoretical results not only have conceptual importance in the field of topological quantum materials but also make clear predictions that can be tested in several experiments.
Humans are sensitive to attention control when predicting others’ actions
Authors: Pesquita Ana , Chapman Craig S. , Enns James T.
Published: July 2016

Significance

This study documents that human social understanding involves not only knowing where someone else is attending, but also sensitivity to how the other’s attention has been directed. The experiments reveal that humans are sensitive to subtle differences in bodily cues that occur when someone else’s attention is controlled by an internal choice vs. an external signal. This finding brings William James’ longstanding distinction between reflexive and voluntary attention squarely into the realm of a modern topic: reading others’ minds through action observation.