bluuebunny/crossref_metadata_2025 huggingface dataset:
Additive fabrication of nanostructures with focused soft X-rays
Authors: Späth Andreas , Tu Fan , Vollnhals Florian , Drost Martin , Krick Calderón Sandra , Watts Benjamin , Fink Rainer H. , Marbach Hubertus
Published: October 2016

In a novel approach a high-resolution soft X-ray microscope has been applied to generate metallic nanostructures by X-ray beam induced decomposition of precursor molecules supplied from the gas phase.
Synthesis and characterisation of cycloruthenated benzhydrazone complexes: catalytic application to selective oxidative cleavage of olefins to aldehydes
Authors: Manikandan Thimma Sambamoorthy , Ramesh Rengan , Semeril David
Published: October 2016

The synthesis and structural characterisation of cyclometalated ruthenium(ii) aroylhydrazone complexes have been described. The complexes were developed as effective catalysts for oxidative cleavage of olefin reactions.
Preparation of mechanical abrasion and corrosion resistant bulk highly hydrophobic material based on 3-D wood template
Authors: Wang Kaili , Dong Youming , Yan Yutao , Qi Chusheng , Zhang Shifeng , Li Jianzhang
Published: October 2016

BH-wood had low free energy microstructures extending throughout the whole volume, and possessed excellent mechanical abrasion and corrosion resistance.
Simultaneous and direct analysis of multiple types of organic contaminants in water based on a MOF decorated with a suitable quantity of Au nanoparticles, using SALDI-TOF MS
Authors: Niu Hongyun , Wang Saihua , Tan Yixin , Song Xiaowei , Cai Yaqi
Published: October 2016

Simultaneous, fast and sensitive analysis of multiple types of organic contaminants using SALDI-TOF MS was realized for the first time.
Soluble silicon patterns and templates: calcium phosphate nanocrystal deposition in collagen type 1
Authors: Birdi-Chouhan G. , Shelton R. M. , Bowen J. , Goldberg-Oppenheimer P. , Page S. J. , Hanna J. V. , Peacock A. , Wright A. J. , Grover L. M.
Published: October 2016

OSA interactsviaionic cross-linking to collagen molecules; free hydroxyl ions recruit CaP nano-precursors and aid nucleation within the fibrils.
Preparation and characterization of a luminescent carbon dots grafted CaSiO3:Eu3+ phosphor for ratiometric fluorescent oxygen sensing
Authors: Wang Li , Zhang Haoran , Zhou Xiaohua , Liu Yingliang , Lei Bingfu
Published: October 2016

In this work, we present a rapid, selective and highly sensitive sensor for the detection of oxygen based on ratiometric fluorescentcarbon dots (CDs) grafted CaSiO3:Eu3+.
Cucurbit[7]uril-threaded fluorene–thiophene-based conjugated polyrotaxanes
Authors: Idris M. , Bazzar M. , Guzelturk B. , Demir H. V. , Tuncel D.
Published: October 2016

The optical and thermal properties of fluorene–thiophene based conjugated polyelectrolytes are altered by threading with CB7.
In situ carbon-coating and Ostwald ripening-based route for hollow Ni3S4@C spheres with superior Li-ion storage performances
Authors: Ji Shaomin , Zhang Liguo , Yu Litao , Xu Xijun , Liu Jun
Published: October 2016

Uniform hollow carbon-coated polydymite microspheres, which display superior Li-ion storage performances, were synthesized via an Ostwald ripening-based hollowing route.
High-performance CuFe2O4 epitaxial thin films with enhanced ferromagnetic resonance properties
Authors: Zhang Ruyi , Liu Ming , Lu Lu , Mi Shao-Bo , Jia Chun-Lin , Wang Hong
Published: October 2016

CuFe2O4 epitaxial films with superior FMR properties compared with bulk material have been successfully fabricated for the first time.
A new multicomponent reaction for direct synthesis of primary γ-nitroamides
Authors: Montes D'Oca Caroline R. , da Silva Jessica C. , Guedes Esthefani P. , Montes D'Oca Marcelo G. , Santos Leonardo S. , Nachtigall Fabiane M. , Russowsky Dennis
Published: October 2016

The multicomponent synthesis of γ-nitroamides were achieved by the use of ammonium carbonate as reagent and catalyst.
The production of bio-jet fuel from Botryococcus braunii liquid over a Ru/CeO2catalyst
Authors: Zhang Kun , Zhang Xu , Tan Tianwei
Published: October 2016

In this study, the conversion fromBotryococcus brauniiliquid to bio-jet fuelviaa Ru/CeO2catalyst was conducted.
The effect of phenol functionality on the characteristic features and performance of fully aromatic polyester thin film composite nanofiltration membranes
Authors: Bera Anupam , Bhalani Dixit V. , Jewrajka Suresh K. , Ghosh Pushpito K.
Published: October 2016

The functionality of phenolic monomers affects the properties and performance of the fully aromatic TFC nanofiltration membrane.
Effect of length on the transport and magnetic properties of diradical substituted molecular wires
Authors: Shil Suranjan , Sarbadhikary Prodipta , Misra Anirban
Published: October 2016

Extended π-conjugated molecules are known to have interesting applications as conducting nanowires, memory devices, and diodes.
Zeolite based solid-phase extraction coupled with UPLC-Q-TOF-MS for rapid analysis of acetylcholinesterase binders from crude extract of Corydalis yanhusuo
Authors: Tao Yi , Jiang Yanhui , Li Weidong , Cai Baochang
Published: October 2016

A very convenient, sensitive and precise solid-phase extraction approach was established for extract and analysis of acetylcholinesterase binders from crude extract of Corydalis yanhusuo.
The preparation of high-quality water-soluble silicon quantum dots and their application in the detection of formaldehyde
Authors: Xu Xiaoling , Ma Shiyao , Xiao Xincai , Hu Yan , Zhao Dan
Published: October 2016

This paper reports the synthesis of water-soluble fluorescence silicon quantum dots (Si QDs) through a hydrothermal route with urea propyl triethoxysilane (UPTES) as the source of silicon and sodium citrate as the deoxidizer.
Continuous flow gas phase photoreforming of methanol at elevated reaction temperatures sensitised by Pt/TiO2
Authors: Caravaca A. , Daly H. , Smith M. , Mills A. , Chansai S. , Hardacre C.
Published: October 2016

Gas phase photoreforming of methanol using a Pt/TiO2 photocatalyst has been performed under flow conditions at elevated temperatures.
One-pot palladium-catalyzed synthesis of sulfonyl fluorides from aryl bromides
Authors: Davies Alyn T. , Curto John M. , Bagley Scott W. , Willis Michael C.
Published: October 2016

A mild, efficient synthesis of sulfonyl fluorides from aryl and heteroaryl bromides utilizing palladium catalysis is described.
Palladium(0)-catalyzed asymmetric C(sp3)–H arylation using a chiral binol-derived phosphate and an achiral ligand
Authors: Yang Lei , Melot Romain , Neuburger Markus , Baudoin Olivier
Published: October 2016

High enantioselectivities can be achieved using an appropriate chiral base/achiral ligand combination in Pd0-catalyzed C(sp3)–H activation.
Stretchable, adhesive and ultra-conformable elastomer thin films
Authors: Sato Nobutaka , Murata Atsushi , Fujie Toshinori , Takeoka Shinji
Published: October 2016

Low elastic modulus and thickness of free-standing thin films fabricated from thermoplastic elastomers show ultra-conformability and high adhesive strength to various surfaces.
Effect of coatings on the green electrode processing and cycling behaviour of LiCoPO4
Authors: Laszczynski Nina , Birrozzi Agnese , Maranski Krzysztof , Copley Mark , Schuster Manfred Erwin , Passerini Stefano
Published: October 2016

Natural compounds such as sucrose and Na-carboxymethyl cellulose enhance the cycling behavior of the high-voltage LiCoPO4 cathode material.
Narrow bandgap conjugated polymers based on a high-mobility polymer template for visibly transparent photovoltaic devices
Authors: Yuan Jianyu , Ford Michael , Ding Guanqun , Dong Huilong , Wang Ming , Han Lu , Li Youyong , Bazan Guillermo C. , Ma Wanli
Published: October 2016

In this contribution, starting from a high mobility polymer P2 with a regioregular D–A–D–A structure, we set out to further optimize the optical bandgap and energy levels for photovoltaic applications.
Blood clot initiation by mesoporous silica nanoparticles: dependence on pore size or particle size?
Authors: Chen Zihao , Li Fan , Liu Changjun , Guan Jing , Hu Xiao , Du Ge , Yao Xinpei , Wu Jimin , Tian Feng
Published: October 2016

The hemostatic efficiency of mesoporous silica nanoparticles depends on pore size more than particle size, and biocompatibility is more related to particle size.
Tools and limitations to study the molecular composition of synapses by fluorescence microscopy
Authors: Maidorn Manuel , Rizzoli Silvio O. , Opazo Felipe
Published: October 2016

The synapse is densely packed with proteins involved in various highly regulated processes. Synaptic protein copy numbers and their stoichiometric distribution have a drastic influence on neuronal integrity and function. Therefore, the molecular analysis of synapses is a key element to understand their architecture and function. The overall structure of the synapse has been revealed with an exquisite amount of details by electron microscopy. However, the molecular composition and the localization of proteins are more easily addressed with fluorescence imaging, especially with the improved resolution achieved by super-resolution microscopy techniques. Notably, the fast improvement of imaging instruments has not been reflected in the optimization of biological sample preparation. During recent years, large efforts have been made to generate affinity probes smaller than conventional antibodies adapted for fluorescent super-resolution imaging. In this review, we briefly discuss the current views on synaptic organization and necessary key technologies to progress in the understanding of synaptic physiology. We also highlight the challenges faced by current fluorescent super-resolution methods, and we describe the prerequisites for an ideal study of synaptic organization.
Mitochondrial form, function and signalling in aging
Authors: Amigo Ignacio , da Cunha Fernanda M. , Forni Maria Fernanda , Garcia-Neto Wilson , Kakimoto Pâmela A. , Luévano-Martínez Luis A. , Macedo Felipe , Menezes-Filho Sergio L. , Peloggia Julia , Kowaltowski Alicia J.
Published: October 2016

Aging is often accompanied by a decline in mitochondrial mass and function in different tissues. Additionally, cell resistance to stress is frequently found to be prevented by higher mitochondrial respiratory capacity. These correlations strongly suggest mitochondria are key players in aging and senescence, acting by regulating energy homeostasis, redox balance and signalling pathways central in these processes. However, mitochondria display a wide array of functions and signalling properties, and the roles of these different characteristics are still widely unexplored. Furthermore, differences in mitochondrial properties and responses between tissues and cell types, and how these affect whole body metabolism are also still poorly understood. This review uncovers aspects of mitochondrial biology that have an impact upon aging in model organisms and selected mammalian cells and tissues.
Correlation of angiotensin I-converting enzyme gene insertion/deletion polymorphism with rheumatic heart disease: a meta-analysis
Authors: Tian Yulong , Ge Zhongchun , Xing Yuliang , Sun Yan , Ying Jie
Published: October 2016

Rheumatic heart disease (RHD) is a serious cardiovascular disorder worldwide. Several articles have reported the effect of angiotensin I-converting enzyme gene insertion/deletion (ACE I/D) polymorphism in RHD risk. However, the results still remain inconsistent. The objective of the present study was to assess more precise estimations of the relationship between ACE I/D variant and RHD susceptibility. Relevant case–control studies published between January 2000 and 2016 were searched in the electronic databases. The odds ratio (OR) with its 95% confidence interval (CI) was employed to calculate the strength of the effect. A total of nine articles were retrieved, including 1333 RHD patients and 1212 healthy controls. Overall, our result did not detect a significant association between ACE I/D polymorphism and RHD risk under each genetic model (P > 0.05). Subgroup analysis by ethnicity showed no positive relationship in Asians as well (P > 0.05). With respect to the severity of RHD, our result found that the frequency differences between mitral valve lesion (MVL), combined valve lesion (CVL) and healthy controls were not significantly different. Furthermore, no significant association was found between female, male RHD patients and the controls regarding to the ACE I/D polymorphism. In conclusion, our result indicated that ACE I/D polymorphism might not be a risk factor for RHD progression based on the existing research results. Additional well-designed studies with larger samples are still needed to confirm these findings.
Fully distributed economic dispatch of distributed generators in active distribution networks considering losses
Authors: Kouveliotis‐Lysikatos Iasonas , Hatziargyriou Nikos
Published: October 2016

The increased complexity of the modern distribution system caused by the installation of a large number of distributed energy resources, dictates the necessity for novel, decentralised schemes for the grid operation. In this study, a fully distributed method for the economic dispatch (ED) problem is proposed that takes into account distribution losses. The solution is reached using only local computations and exchange of messages between adjacent nodes without the need of a central coordinating entity. The algorithm presents plug‐and‐play capabilities and is self‐triggered. More specifically, the ED is formulated as a resource allocation problem and a fully distributed algorithm is employed to acquire the solution that is based on the replicator equation model. It takes into account the technical constraints of the generators and it is extended in order to integrate the distributed calculation of active power losses using distributed estimation of the loss penalty factors. Guarantees for the convergence and optimality of the proposed algorithm are provided along with numerical results that demonstrate the effectiveness and efficiency of the algorithm.
Power‐dependent droop‐based control strategy for multi‐terminal HVDC transmission grids
Authors: Stamatiou Georgios , Bongiorno Massimo
Published: October 2016

The concept of voltage source converter based multi‐terminal high‐voltage direct current (MTDC) grids, represents both challenges and opportunities for the future of large power transfer and integration of renewable energy sources. For this kind of grids, the control aspect is of great importance, with voltage‐droop based methods considered as one of the most attractive solutions. All existing strategies are designed to maintain the level of voltage in the MTDC grid constant during unexpected events, thus sacrificing the power flow. The aim of this study is to propose a new droop controller structure that maintains the dc‐grid voltage close to the nominal value and at the same time tries to preserve the power flow in the dc grid, following events such as faults or disconnection of stations. The control scheme is presented and simulations are carried out in a four‐ and five‐terminal MTDC grid, proving the validity of the concept.
Validation study of an approximate 2014 European power‐flow model using PowerGAMA
Authors: Lie Arne Ø. , Rye Eirik A. , Svendsen Harald G. , Farahman Hossein , Korpås Magnus
Published: October 2016

This study presents a validation study of an approximated model of the European power system in 2014. A lightweight and open‐source power‐flow tool is used for this study. The tool and the model are publicly available and can be adapted to study future impact of large investments in the power system, specifically large‐scale integration of renewable energy. The input dataset is based on a prior work, but it has been substantially updated for 2014. To maintain all aspects of the model open‐source, only publicly available data was implemented. The modelling approach and simplifications are explained. Comparison of the simulation results with actual data on cross‐ border flows and energy mix for 2014 shows acceptable correlation. The model is able to capture main characteristics of the power system, such as reservoir handling, hydro pump pattern, and seasonal variation on cross‐ border flows.
Real‐time implementation of SPV system with DSTATCOM capabilities in three‐phase four‐wire distribution system
Authors: Shivam Shashwat , Hussain Ikhlaq , Singh Bhim
Published: October 2016

This study deals with a real‐time implementation of solar photovoltaic (SPV) grid integrated system possessing distributed static compensator (DSTATCOM) capabilities with three‐phase four‐wire voltage source converter (VSC) topology using least mean eighth control algorithm. The proposed system has an SPV array, a VSC, three single‐phase non‐linear loads connected to the grid and a ripple filter. The SPV and VSC together behave as a DSTATCOM and additionally supplies SPV power to the grid. The DSTATCOM reduces the total harmonic distortion of the grid currents, maintains the voltage of point of common coupling and improves the power factor. The maximum extraction of incident solar power on SPV array is achieved through an incremental conductance maximum power point tracking technique. The behaviour of the system is studied by developing a prototype with an SPV array simulator.
An efficient small size electromagnetic energy harvesting sensor for low‐DC‐power applications
Authors: Meddour Fayçal , Dibi Zohir
Published: October 2016

An efficient small size electromagnetic energy harvesting sensor for low‐DC‐power applications is proposed. The sensor consists of two main parts: a dual polarisation square patch antenna used to collect the RF energy at a central frequency of 2.45 GHz, and two voltage doublers rectifier circuit for the RF‐to‐DC conversion. The overall size of the design is 50 × 50 × 6.2 mm3. Firstly, the antenna is designed using high‐frequency structure simulator software; followed by the design of the rectifier circuit in advanced design system. After simulations, a sensor prototype is fabricated using F4B as the antenna substrate. Measurements show that the sensor achieves a comparatively high maximum measured efficiency of 41% for a power level of −10 dBm. The sensor has a simple structure, it is compact sized, light weight, and presents a high RF‐to‐DC conversion efficiency for low‐RF‐power levels which can be used to charge different low‐DC‐power devices.
Evaluation esthétique du profil cutané : une étude
transversale
Authors: Hélou Marwan EL , Kassis Adib , Haddad Robert , Ghoubril Joseph
Published: October 2016

Introduction : L’objectif de cette étude est d’identifier le profil le plus
attirant parmi sept photographies distribuées à trois groupes : orthodontistes, dentistes
et profanes. Matériels et méthodes : Deux photographies de profil d’un garçon
et d’une fille en classe I squelettique ont été modifiées de six façons différentes dans
le sens antéro-postérieur au niveau du maxillaire et/ou de la mandibule à l’aide du
logiciel Dolphin Imaging System®. Les participants, au nombre de 120, ont classé les
photographies de chaque sexe du plus au moins attirant. Résultats : Le profil
droit féminin et masculin ont été les mieux classés. Cependant, la protrusion des lèvres
chez la femme et la rétromaxillie chez l’homme sont tolérées. Discussion :
Nos résultats expriment l’opinion moyenne d’une société caucasienne, cela ne veut
pas dire que n’importe quel profil droit est perçu comme beau ou attirant, d’où
l’importance d’un plan de traitement individualisé prenant en considération l’esthétique
faciale de chaque patient.
Développement normal et pathologique de la mandibule.
Déductions pratiques en orthopédie maxillo-dento-faciale
Authors: Salagnac Jean-Michel
Published: October 2016

Introduction : La mandibule est composée de différentes unités qui ont leurs
propres particularités d’apparition, d’ossification de développement et leurs pathologies
spécifiques. Ces anomalies du développement doivent être bien connues des orthodontistes
pour éviter d’entreprendre des traitements orthopédiques ou orthodontiques voués à l’échec
et pour comprendre l’insuccès des traitements «conventionnels». Le bon développement de
chaque unité est indispensable pour que la mandibule acquiert un développement optimal et
occupe une place normale dans l’ensemble cranio-facial. La position de la mandibule dans
l’ensemble cranio-facial est aussi conditionnée par son implantation sur la base du crâne.
Matériels et méthodes : À partir d’une étude sémiologique détaillée et
d’une analyse radiologique structurale et architecturale tridimensionnelle de cas
cliniques, cet article étudie les différentes anomalies de développement des unités
mandibulaires et leurs répercussions sur l’ensemble cranio-facial. Résultats :
La connaissance de ces anomalies et cette méthode d’analyse permettent un dépistage
précoce, évitent d’entreprendre des traitements orthopédiques ou orthodontiques voués à
l’échec, permettent de comprendre l’insuccès des traitements «conventionnels», constituent
un guide thérapeutique orthopédico-chirurgical et permettent d’informer correctement les
patients. Les anomalies du développement et de positionnement de la mandibule sur la base
du crâne et leur retentissement sur l’équilibre squelettique cranio-facial sont bien mises
en évidence par l’analyse structurale et architecturale, précisant les différentes entités
cliniques de classes II et classes III squelettiques. Discussion : En
orthopédie maxillo-dento-faciale, devant une pathologie d’origine mandibulaire, il est
indispensable de faire une lecture radiographique attentive de chaque unité de la
mandibule, de rechercher les formes mineures des anomalies et d’apprécier la position de
la mandibule sur la base du crâne et par rapport aux structures avoisinantes : crâne,
rachis cervical, maxillaire.
Numerical study on the freely falling plate: Effects of density ratio and thickness-to-length ratio
Authors: Wang Y. , Shu C. , Teo C. J. , Yang L. M.
Published: October 2016

A numerical study on two-dimensional (2D) rectangular plates falling freely in water is carried out in the range of 1.2 ≤ ρs/f ≤ 5.0 and 1/20 ≤ β ≤ 1/4, where ρs/f is the solid-to-water density ratio and β is the plate thickness-to-length ratio. To study this problem, the immersed boundary-lattice Boltzmann flux solver in a moving frame is applied and validated. For the numerical result, a phase diagram is constructed for fluttering, tumbling, and apparent chaotic motions of the plate parameterized using ρs/f and β. The evolution of vortical structures in both modes is decomposed into three typical stages of initial transient, deep gliding, and pitching-up. Various mean and instantaneous fluid properties are illustrated and analyzed. It is found that fluttering frequencies have a linear relationship with the Froude number for all cases considered. Lift forces on fluttering plates are linearly dependent on the angle of attack α at the cusp-like turning point when α≥π/5. Hysteresis of the lift force on fluttering plates is observed and explained whilst the drag forces are the same when α has the same value. Meanwhile, the drag force in the tumbling motion may have a positive propulsive effect when the plate begins a tumbling rotation from α = π/2.
Effects of the tube diameter on the propagation of helium plasma plume via electric field measurement
Authors: Wu S. , Lu X. , Yue Y. , Dong X. , Pei X.
Published: October 2016

In this work, the dependence of the length of plasma plume, propagation velocity, electric field in the streamer head, and propagation mode transition on the tube diameter varied in the range of 0.07–4 mm is investigated for the first time. The atmospheric-pressure helium plasma plume, ignited by a positive pulsed direct current voltage with a pulse rising time of 60 ns, is confined inside a long glass tube. First, the decreased tube diameter results in the reduction of the length of plasma plume but the growth of aspect ratio of plasma plume. Second, as the tube diameter decreases, the average velocity of the propagation of plasma plume increases first, then reaches a maximum value at tube diameter of 1 mm, and finally decreases for the tube diameter decreasing further. Third, the electric field in the streamer head, determined by the method based on Stark polarization spectroscopy of He 447 nm line, increases monotonically from 9 kV/cm to 20 kV/cm with the tube diameter decreasing from 4 mm to 0.6 mm. Finally, when the tube diameter is further reduced to 0.07 mm, high-speed photography reveals that the propagation mode of the plasma plume transits from the plasma bullet to the continuous plasma column.
Static phase improvements in the LNE watt balance
Authors: Pinot P. , Espel P. , Liu Y. , Thomas M. , Ziane D. , Palacios-Restrepo M.-A. , Piquemal F.
Published: October 2016

This paper describes the mechanical and electrical modifications carried out on the LNE watt balance to reduce the noise level associated with the static phase. The mechanical improvements concern the home-made balance beam using flexure hinges as pivots of the force comparator. The electrical improvements involve the source used to servo-control the equilibrium position of the beam during the static phase. All these modifications have led to a significant improvement of the repeatability and reproducibility of the results of static phase measurements.
Versatile soft X-ray-optical cross-correlator for ultrafast applications
Authors: Schick Daniel , Eckert Sebastian , Pontius Niko , Mitzner Rolf , Föhlisch Alexander , Holldack Karsten , Sorgenfrei Florian
Published: October 2016

We present an X-ray-optical cross-correlator for the soft (>150 eV) up to the hard X-ray regime based on a molybdenum-silicon superlattice. The cross-correlation is done by probing intensity and position changes of superlattice Bragg peaks caused by photoexcitation of coherent phonons. This approach is applicable for a wide range of X-ray photon energies as well as for a broad range of excitation wavelengths and requires no external fields or changes of temperature. Moreover, the cross-correlator can be employed on a 10 ps or 100 fs time scale featuring up to 50% total X-ray reflectivity and transient signal changes of more than 20%.
X-ray excited luminescence of polystyrene-based scintillator loaded with LaPO4–Pr nanoparticles
Authors: Demkiv T. M. , Halyatkin O. O. , Vistovskyy V. V. , Gektin A. V. , Voloshinovskii A. S.
Published: October 2016

Polystyrene film nanocomposites of 0.3 mm thickness with embedded LaPO4-Pr nanoparticles (40 wt. %) have been synthesized. The luminescent and kinetic properties of these polystyrene composites with embedded LaPO4-Pr nanoparticles upon pulse X-ray excitation have been studied. The luminescence intensity of this polystyrene material significantly increases as it is loaded with inorganic LaPO4-Pr nanoparticles. Nanocomposite films reveal luminescence spectra typical for polystyrene activators (p-Terphenyl and POPOP) and two components of decay time kinetics of luminescence with 12 ns and 2.8 ns time constants, depending on nanoparticle sizes. The component with 12 ns decay constant arises due to the radiative transfer of the 5d-4f-emission of the Pr3+ ions in the LaPO4 nanoparticles to the polystyrene. The decay component with the time constant 2.8 ns originates from luminescence of polystyrene matrix excited by electrons emitted from nanoparticles due to the photoeffect. This nonradiative mechanism of energy transfer from nanoparticles to polystyrene matrices is determinative for nanoparticles, as their sizes are smaller than a mean free path of an electron.
Analytical approach to high harmonics spectrum in the nanobunching regime
Authors: Cherednychek Mykyta , Pukhov Alexander
Published: October 2016

With high-order harmonic generation (HHG) from plasma surfaces, it is possible to turn a laser pulse into a train of attosecond or even zeptosecond pulses in the backward radiation. These attosecond pulses may be several orders of magnitude higher than that of the laser pulse under appropriate conditions. We study this process in detail, especially the nanobunching of plasma electron density. We derive an analytical expression that describes the electron density profile and obtain a good agreement with particle-in-cell simulation results. We investigate the most efficient case of HHG at moderate laser intensity (I≈2×1020 W/cm2) on the over-dense plasma slab with an exponential profile pre-plasma. Subsequently, we calculate the spectra of a single attosecond pulse from the backward radiation using our expression for density shape in combination with the equation for the spectrum of nanobunch radiation.
Enhanced emissive and lasing characteristics of nano-crystalline MAPbBr3 films grown via anti-solvent precipitation
Authors: Lafalce E. , Zhang C. , Zhai Y. , Sun D. , Vardeny Z. V.
Published: October 2016

Control of the nano-scale crystal size distribution in films of organic-inorganic lead-tri-bromide perovskites is achieved through a recently reported solution-based, anti-solvent treatment method [H. Cho et al., Science 350, 1222 (2015)]. The treated films are shown to be high quality, optically smooth with excellent emissive and optical gain properties including higher photoluminescence yield and reduced threshold for laser action. The improved lasing is shown to originate from a synergistic combination of a reduction in waveguide losses and a decrease in the non-radiative decay rate of the excited state population, compared to untreated films. The net gain is increased by a factor of two upon anti-solvent treatment and reaches a respectable value of ≈300 cm−1.
Compositional inhomogeneities in AlGaN thin films grown by molecular beam epitaxy: Effect on MSM UV photodetectors
Authors: Pramanik Pallabi , Sen Sayantani , Singha Chirantan , Roy Abhra Shankar , Das Alakananda , Sen Susanta , Bhattacharyya A.
Published: October 2016

Ultraviolet (UV) MSM photodetectors (PD) based on AlGaN alloys find many applications, including flame sensing. In this work we investigate the dependence of AlGaN based photodetectors grown by MBE on the kinetics of growth. MSM photodetectors were fabricated in the interdigitated configuration with Ni/Au contacts having 400 μm finger length and 10 μm finger spacing. Bulk Al0.4Ga0.6N films were grown on to sapphire substrates using an AlN buffer layer. A series of PDs were developed using the Al0.4Ga0.6N films grown under different group III/V flux ratios ranging from stoichiometric conditions to much higher than unity. Upon testing, it was observed that the otherwise identical photodetectors show significant decrease in dark current as AlGaN deposition conditions change from stoichiometric to excess group III, due to reduction of unintentional incorporation of oxygen-related point defects. In addition, the intensity and spectral dependence of the photocurrent also change, showing an extended low energy tail for the former and a sharp and prominent excitonic peak for the latter. The optical transmission measurements indicate a variation in Urbach energy with deposition conditions of the AlGaN films, although they have the same absorption edge. While all samples show a single red-shifted photoluminescence peak at room temperature, upon cooling, multiple higher energy peaks appear in the photoluminescence (PL) spectra, indicating that the alloys contain complex compositional inhomogeneities. Two types of alloy fluctuations, determined by the growth conditions, have been identified that modulate the optoelectronic properties of AlGaN by changing the spatial localization of excitons, thereby altering their stability. We identified that growth under stoichiometric conditions leads to compositional inhomogeneities that play a detrimental role in the operation of MSM photodetectors, which reduces the sharpness of the sensitivity edge, while growth under excess metal conditions enhances it.
Size dependence of discrete change in magnetization in single crystal of chiral magnet Cr1/3NbS2
Authors: Tsuruta K. , Mito M. , Kousaka Y. , Akimitsu J. , Kishine J. , Togawa Y. , Inoue K.
Published: October 2016

The single crystal of a chiral magnet Cr1/3NbS2 exhibits discrete changes in magnetization (M) in response to changes in magnetic field (H) triggered by the formation of a chiral soliton lattice (CSL). In order to provide evidence of this phenomenon, the study of the size effect is indispensable. We investigated the effects of size on this phenomenon by the use of two single crystals, (A) and (B), whose crystal sizes along the c-axis were 110 μm and 60 μm, respectively. First, in (A), the large jumps of M observed in the process of decreasing H exhibited inconsistent features, whereas the largest and second-largest jumps in (B) exhibited reproducibility for both the value of H and the magnitude of the M jumps. This confirms that these large jumps do not originate from the Barkhausen effect, as this effect would result in M jumps appearing at random values of H. When the system size of a sample becomes smaller, the features of the Barkhausen effect are suppressed. Second, as for the successive jumps observed in the H region where the rapid change in M is entirely seen for both the samples, the number of observed M jumps for (B) is more than that for (A). Indeed, the number of the domain wall due to the 2π-soliton in the CSL increases, as the c-axis length of the single crystal increases. However, a series of M jumps must appear in a limited H region below the critical field of the order of 2 kOe. The greater the number of M jumps, the more difficult the detection of the M jump will be in the H resolution of the present setup. Thus, the effects of size on the M jumps observed in the present setup can be understood within the framework of the CSL formation.
Resonant frequencies of cantilevered sheets under various clamping configurations immersed in fluid
Authors: Shen Naijian , Chakraborty Debadi , Sader John E.
Published: October 2016

Immersion of an elastic cantilevered sheet in a fluid can strongly affect its dynamic response. While significant effort has been expended in studying slender cantilevered sheets, the behavior of wide sheets has received far less attention. Here we study the clamping configuration's effect on the vibrational dynamics of wide cantilever sheets of macroscopic size, which naturally generate inviscid flows. Three practically relevant clamping configurations are investigated: clamping into (i) a thin and rigid horizontal plate, (ii) a rigid vertical wall, and (iii) a rigid line. These are found to produce different resonant frequencies, as expected from the nonlocal flows generated by these cantilevers. The resulting formulas are joined to an existing expression for slender cantilevers, leading to a universal formula valid for all aspect ratios (cantilever length/width) and mode numbers; accuracy is verified using finite element analysis. This study is expected to be of practical value in a host of engineering applications, such as those that utilize fluid-structure interactions for energy harvesting and aerodynamic design.
Investigation on the crystallization mechanism difference between FINEMET® and NANOMET® type Fe-based soft magnetic amorphous alloys
Authors: Wang Yaocen , Zhang Yan , Takeuchi Akira , Makino Akihiro , Kawazoe Yoshiyuki
Published: October 2016

In this article, the atomic behaviors of Nb and P in Fe-based amorphous alloys during nano-crystallization process were studied by the combination of ab initio molecular dynamics simulations and experimental measurements. The inclusion of Nb is found to be tightly bonded with B, resulting in the formation of diffusion barrier that could prevent the over-growth of α-(Fe, Si) grains and the promotion of larger amount of α-(Fe, Si) participation. The P inclusion could delay the diffusion of the metalloids that have to be expelled from the α-(Fe, Si) crystallization region so that the grain growth could be reduced with fast but practically achievable heating rates. The combined addition of P and Nb in high Fe content amorphous alloys failed in exhibiting the potential of good magnetic softness with slow heating (10 K/min) annealing at various temperatures. The sample with optimum crystallization process with confined grain size was annealed at 653 K, with the grain size of 31 nm and a coercivity of ∼120 A/m, much too large to meet the application requirements and to be compared with the currently well-studied alloy systems. This attempt suggests that the inclusion of early transition metal elements might not be effective enough to suppress grain growth in crystallizing high Fe content amorphous alloys.
Measurements of slip length for flows over graphite surface with gas domains
Authors: Li Dayong , Wang Yuliang , Pan Yunlu , Zhao Xuezeng
Published: October 2016

We present the measurements of slip lengths for the flows of purified water over graphite surface covered with surface nanobubbles or nano/micropancakes, which can be produced after using high temperature water to replace low temperature water. The slip length values measured on bare graphite surface, nano/micropancake or nanobubble covered graphite surfaces are about 8 nm, 27 nm, and 63 nm, respectively. Our results indicate that the gaseous domains formed at the solid-liquid interface, including surface nanobubbles and nano/micropancakes, could act as a lubricant and significantly increase slip length.
Photocapacitance spectroscopy of InAlN nearly lattice-matched to GaN
Authors: Lugani L. , Py M. A. , Carlin J.-F. , Grandjean N.
Published: October 2016

We study the deep levels in InAlN nearly lattice-matched to GaN by photocapacitance spectroscopy. This technique allows the study of very deep levels having too slow thermal emission rates to be detected by other deep level spectroscopy techniques. We will identify a broad band of deep levels centered 1.7 eV below the InAlN conduction band edge. The deep level band is characterized by a negligible Franck-Condon shift and by a broadening parameter ΔE = 0.38 eV. Furthermore, we will show evidences for a second class of deep levels with optical ionization energy >2 eV, which will be attributed to previously reported oxygen-related DX centers.
A broadband configuration for static Fourier transform spectroscopy with bandpass sampling
Authors: Sardari Behzad , Davoli Federico , Özcan Meriç
Published: October 2016

In this work a new broadband static Fourier transform spectrometer (static-FTS) configuration based on the division of the spectrum into multiple narrow-bands is proposed. This configuration not only decreases the spectrometer size but also allows operation in the traditional spectrometer wavelength range, namely, 400 nm–1100 nm with 1 cm−1 or better resolution. This technique solves the Nyquist sampling rate issue and enables us to record high resolution spectrums with regular CCDs. An algorithm is developed to process the signal and calculate the Fourier transform of the recorded interferograms on the CCD camera.
Auxetic nanomaterials: Recent progress and future development
Authors: Jiang Jin-Wu , Kim Sung Youb , Park Harold S.
Published: October 2016

Auxetic materials (materials with negative Poisson's ratio) and nanomaterials have independently been, for many years, two of the most active research fields in material science. Recently, these formerly independent fields have begun to intersect in new and interesting ways due to the recent discovery of auxeticity in nanomaterials like graphene, metal nanoplates, black phosphorus, and others. Here, we review the research emerging at the intersection of auxeticity and nanomaterials. We first survey the atomistic mechanisms, both intrinsic and extrinsic, that have been found, primarily through atomistic simulations, to cause auxeticity in nanomaterials. We then outline the available experimental evidence for auxetic nanomaterials. In order to lay the groundwork for future work in this exciting area, we close by discussing several future prospects as well as the current challenges in this field.
Comment on “Are polynuclear superhalogens without halogen atoms probable? A high-level ab initio case study on triple-bridged binuclear anions with cyanide ligands” [J. Chem. Phys. 140, 094301 (2014)]
Authors: Díaz-Tinoco Manuel , Ortiz J. V.
Published: October 2016

For the vertical electron detachment energies of triply-bridged Mg2(CN)5− superhalides, the Outer Valence Green Function (OVGF) yields results similar to those of the coupled-cluster singles and doubles plus approximate triples, or CCSD(T), method. Invalid comparisons between states with different symmetry or localization properties underlie the assertion of Yin et al that OVGF produces large discrepancies with respect to CCSD(T) for several isomers of Mg2(CN)5−.
Si nanocrystals and nanocrystal interfaces studied by positron annihilation
Authors: Kujala J. , Slotte J. , Tuomisto F. , Hiller D. , Zacharias M.
Published: October 2016

Si nanocrystals embedded in a SiO2 matrix were studied with positron annihilation and photoluminescence spectroscopies. Analysis of the S- and W-parameters for the sample annealed at 800 °C reveals a positron trap at the interface between the amorphous nanodots and the surrounding matrix. Another trap state is observed in the 1150 °C heat treated samples where nanodots are in a crystalline form. Positrons are most likely trapped to defects related to dangling bonds at the surface of the nanocrystals. Passivation of the samples results on one hand in the decrease of the S-parameter implying a decrease in the open volume of the interface state and, on the other hand, in the strengthening of the positron annihilation signal from the interface. The intensity of the photoluminescence signal increases with the formation of the nanocrystals. Passivation of samples strengthens the photoluminescence signal, further indicating a successful deactivation of luminescence quenching at the nanocrystal surface. Strengthening of the positron annihilation signal and an increase in the photoluminescence intensity in passivated silicon nanocrystals suggests that the positron trap at the interface does not contribute to a significant extent to the exciton recombination in the nanocrystals.
Enhancing isolation of antenna arrays by simultaneously blocking and guiding magnetic field lines using magnetic metamaterials
Authors: Liu Zhaotang , Wang Jiafu , Qu Shaobo , Zhang Jieqiu , Ma Hua , Xu Zhuo , Zhang Anxue
Published: October 2016

In this article, we propose to enhance the isolation of antenna arrays by manipulating the near-field magnetic coupling between adjacent antennas using magnetic metamaterials (MMs). Due to the artificially designed negative or large permeability, MMs can concentrate or block the magnetic field lines where they are located, which allows us to tune the near-field magnetic coupling strengths between antennas. MMs can play a two-fold role in enhancing antenna isolation. On one hand, the magnetic fields can be blocked in gaps between adjacent antennas using MMs with negative permeability; on the other hand, the magnetic fields can be pulled towards the borders of the antenna array using MMs with large permeability. As an example, we demonstrated a four-element patch antenna array with split-ring resonators (SRR) integrated in the substrate. The measured results show that the isolation can be enhanced by more than 10 dB with the integration of SRRs, even if the gap between antennas is only about 0.082λ. This work provides an effective alternative to the design of high-isolation antenna arrays.
Band gap widening at random CIGS grain boundary detected by valence electron energy loss spectroscopy
Authors: Keller Debora , Buecheler Stephan , Reinhard Patrick , Pianezzi Fabian , Bissig Benjamin , Carron Romain , Hage Fredrik , Ramasse Quentin , Erni Rolf , Tiwari Ayodhya N.
Published: October 2016

Cu(In,Ga) Se2 (CIGS) thin film solar cells have demonstrated very high efficiencies, but still the role of nanoscale inhomogeneities in CIGS and their impact on the solar cell performance are not yet clearly understood. Due to the polycrystalline structure of CIGS, grain boundaries are very common structural defects that are also accompanied by compositional variations. In this work, we apply valence electron energy loss spectroscopy in scanning transmission electron microscopy to study the local band gap energy at a grain boundary in the CIGS absorber layer. Based on this example, we demonstrate the capabilities of a 2nd generation monochromator that provides a very high energy resolution and allows for directly relating the chemical composition and the band gap energy across the grain boundary. A band gap widening of about 20 meV is observed at the grain boundary. Furthermore, the compositional analysis by core-loss EELS reveals an enrichment of In together with a Cu, Ga and Se depletion at the same area. The experimentally obtained results can therefore be well explained by the presence of a valence band barrier at the grain boundary.
Three-dimensional ultra-broadband focusing flat mirror for airborne sound
Authors: Fan Xu-Dong , Zhu Yi-Fan , Liang Bin , Yang Jing , Yin Lei-lei , Yang Jun , Cheng Jian-Chun
Published: October 2016

We report the theoretical design, numerical simulation, and experimental demonstration of a flat mirror capable to efficiently focus the reflected sound in three-dimensional space within an ultra-broad band. The proposed mirror is implemented with a textured rigid surface, enabling simple design and easy fabrication. We analytically derive the distribution of geometric parameters needed for producing ultra-broadband focusing, and verify the performance of resulting mirror both numerically and experimentally. Furthermore, our scheme allows further extending of the working band by resizing individual elements. Our design with simplicity and capability may promote the application of focusing devices generally subject to limited bandwidth.
Delay time embedding of mass loss avalanches in a fusion plasma-oriented sandpile model
Authors: Bowie C. A. , Dendy R. O. , Hole M. J.
Published: October 2016

The sandpile paradigm is widely used to model aspects of the phenomenology of magnetically confined fusion (MCF) plasmas, including enhanced confinement, edge pedestals and, potentially, the impulsive energy and particle release process known as ELMing. Here we identify new points of contact between ELMing and the systemwide avalanches in a sandpile. We compare the quantified response [Calderon et al., Phys. Plasmas 20, 042306 (2014)] to increased fuelling of the time sequence of edge localised mode events in a series of similar Joint European Torus plasmas with the response to increased fuelling of the time sequence of systemwide avalanches in a sandpile model [Chapman et al., Phys. Rev. Lett. 86, 2814 (2001)] that has well established links to MCF plasma phenomenology. Both the probability density functions of inter-event time intervals, and delay time embeddings of event time sequences, at different fuelling rates, show common features and point to shared underlying physics.
Structural analysis of the epitaxial interface Ag/ZnO in hierarchical nanoantennas
Authors: Sanchez John Eder , Santiago Ulises , Benitez Alfredo , Yacamán Miguel José , González Francisco Javier , Ponce Arturo
Published: October 2016

Detectors, photo-emitter, and other high order radiation devices work under the principle of directionality to enhance the power of emission/transmission in a particular direction. In order to understand such directionality, it is important to study their coupling mechanism of their active elements. In this work, we present a crystalline orientation analysis of ZnO nanorods grown epitaxially on the pentagonal faces of silver nanowires. The analysis of the crystalline orientation at the metal-semiconductor interface (ZnO/Ag) is performed with precession electron diffraction under assisted scanning mode. In addition, high resolution X-ray diffraction on a Bragg-Brentano configuration has been used to identify the crystalline phases of the arrangement between ZnO rods and silver nanowires. The work presented herein provides a fundamental knowledge to understand the metal-semiconductor behavior related to the receiving/transmitting mechanisms of ZnO/Ag nanoantennas.