bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermodynamically neutral Kubas-type hydrogen storage using amorphous Cr(iii) alkyl hydride gels
Authors: Morris Leah , Trudeau Michel L. , Reed Daniel , Book David , Antonelli David M.
Published: March 2015

We present chromium(iii) hydride gels that store 5.08 wt% H2 at 160 bar and 298 K with a measured enthalpy of H2 adsorption of +0.37 kJ mol−1 H2.
Comparing a series of 8-quinolinolato complexes of aluminium, titanium and zinc as initiators for the ring-opening polymerization of rac-lactide
Authors: Bakewell Clare , Fateh-Iravani Giovanna , Beh Daniel W. , Myers Dominic , Tabthong Sittichoke , Hormnirun Pimpa , White Andrew J. P. , Long Nicholas , Williams Charlotte K.
Published: March 2015

The preparation, characterization and properties of a series of 8-hydroxy quinolinolate complexes of Ti(iv), Al(iii) and Zn(ii) are presented. The complexes are active initiators for rac-lactide polymerizations: their performances are compared.
Synthesis, characterisation, and dehydrocoupling ability of zirconium complexes bearing hindered bis(amido)silyl ligands
Authors: Lummis Paul A. , McDonald Robert , Ferguson Michael J. , Rivard Eric
Published: March 2015

Electron-deficient zirconium complexes bearing bis(amido)silyl ligands have been synthesised, and their use in the catalytic dehydrocoupling of amine-boranes was explored.
Peripheral substitution as a tool for tuning electron-accepting properties of phthalocyanine analogs in intramolecular charge transfer
Authors: Cidlina Antonin , Novakova Veronika , Miletin Miroslav , Zimcik Petr
Published: March 2015

Efficiency of intramolecular charge transfer correlates with Hammett constants of peripheral substituents and the first reduction potential of tetrapyrazinoporphyrazines.
Positive onset potential and stability of Cu2O-based photocathodes in water splitting by atomic layer deposition of a Ga2O3buffer layer
Authors: Li Changli , Hisatomi Takashi , Watanabe Osamu , Nakabayashi Mamiko , Shibata Naoya , Domen Kazunari , Delaunay Jean-Jacques
Published: March 2015

The improved energy band alignment of Pt/TiO2/Ga2O3/Cu2O structure results in a positive onset potential of ∼1 Vvs.RHE and a stable cathodic photocurrent under appropriate TiO2deposition temperature.
A fast and switchable microfluidic mixer based on ultrasound-induced vaporization of perfluorocarbon
Authors: Bezagu Marine , Arseniyadis Stellios , Cossy Janine , Couture Olivier , Tanter Mickael , Monti Fabrice , Tabeling Patrick
Published: March 2015

We report here a remotely induced and switchable control of microfluidic mixing triggered by ultrasound. The method is based on localized vaporization of a perfluorocarbon (PFC) phase at the focal zone of a transducer leading to efficient mixing of two adjacent fluids.
Loss of pdr-1/parkin influences Mn homeostasis through altered ferroportin expression in C. elegans
Authors: Chakraborty Sudipta , Chen Pan , Bornhorst Julia , Schwerdtle Tanja , Schumacher Fabian , Kleuser Burkhard , Bowman Aaron B. , Aschner Michael
Published: March 2015

This study provides further support that altered metal homeostasis is a critical component of PD pathophysiology.
Facile, efficient, and environmentally friendly α- and aromatic regioselective chlorination of toluene using KHSO5 and KCl under catalyst-free conditions
Authors: Çimen Yasemin , Akyüz Seçkin , Türk Hayrettin
Published: March 2015

The nontoxic, green, safe, stable, and inexpensive reagents Oxone and KCl were employed in the non-catalyzed chlorination of toluene at room temperature.
A selective colorimetric chemosensor with an electron-withdrawing group for multi-analytes CN− and F−
Authors: Lee Hee Joo , Park Sung Jun , Sin Hyen Je , Na Yu Jeong , Kim Cheal
Published: March 2015

A colorimetric chemosensor with an electron-withdrawing group (–NO2) 1 for the detection of CN− and F− was developed.
Fabrication of flexible, transparent and conductive films from single-walled carbon nanotubes with high aspect ratio using poly((furfuryl methacrylate)-co-(2-(dimethylamino)ethyl methacrylate)) as a new polymeric dispersant
Authors: Lee Taeheon , Kim Byunghee , Kim Sumin , Han Jong Hun , Jeon Heung Bae , Lee Young Sil , Paik Hyun-jong
Published: March 2015

We synthesized p(FMA-co-DMAEMA) for the dispersion of SWCNTs while maintaining their high aspect ratios.
In situ fabrication of a perfect Pd/ZnO@ZIF-8 core–shell microsphere as an efficient catalyst by a ZnO support-induced ZIF-8 growth strategy
Authors: Lin Lu , Zhang Tong , Liu Haiou , Qiu Jieshan , Zhang Xiongfu
Published: March 2015

A ZnO support-induced strategy is presented for in situ fabrication of a Pd/ZnO@ZIF-8 core–shell catalyst, which performed with good size-selectivity, stability and anti-poisoning in the liquid hydrogenation of alkenes.
Raman study of laser-induced heating effects in free-standing silicon nanocrystals
Authors: Han Lihao , Zeman Miro , Smets Arno H. M.
Published: March 2015

The size-dependent temperatures of free-standing Si nanocrystals under laser illumination are determined by Raman spectroscopy.
Diastereoselective tandem reactions of substituted 3-sulfolenes with bis-vinyl ketones leading to highly functionalized bicyclic and tricyclic frameworks
Authors: Brant Michael G. , Friedmann Jordan N. , Bohlken Connor G. , Oliver Allen G. , Wulff Jeremy E.
Published: March 2015

Addition of substituted butadiene sulfones to substituted bis-vinyl ketones permits selective access to a broad range of structural types.
Copper loaded cross-linked poly(ionic liquid): robust heterogeneous catalyst in ppm amount
Authors: Pourjavadi Ali , Hosseini Seyed Hassan , Matloubi Moghaddam Firouz , Ayati Seyed Ebrahim
Published: March 2015

A novel heterogeneous copper catalyst was synthesized in which poly(1-vinyl imidazole-co-ionic liquid) was used as a solid heterogeneous support.
Copper–silver oxide nanowires grown on an alloy electrode as an efficient electrocatalyst for water oxidation
Authors: Huang Xing , Xie Minghao , Chen Yihan , Zong Qingshuang , Liu Ziyu , Jin Yong
Published: March 2015

An efficient oxygen-evolving electrode is facilely fabricated based on CuO–Ag2O nanowires grown in situ on an alloy substrate.
Novel conjugated Ag@PNIPAM nanocomposites for an effective antibacterial wound dressing
Authors: Gao Shengping , Ge Wei , Zhao Chunqiu , Cheng Chuansheng , Jiang Hui , Wang Xuemei
Published: March 2015

It is well known that nanosilver or silver ions could act as an effective antibacterial agent without the development of bacterial resistance but long term exposure may induce in vivo toxicity.
Synthesis of functionalized γ-lactones via a three-component cascade reaction catalyzed by consecutive N-heterocyclic carbene systems
Authors: Zhao Qian , Han Bo , Wang Biao , Leng Hai-Jun , Peng Cheng , Huang Wei
Published: March 2015

Two consecutive N-heterocyclic carbene (NHC) catalytic systems were combined in a one-pot cascade reaction for the assembly of aromatic aldehydes and 2-haloenals into a structurally complex γ-lactone backbone.
A green approach to crosslinked polymer microspheres with undoped methacrylate monomers and their potential application as dental restorative materials
Authors: Gu Xiangling , Song Xinfeng , Zhang Yancong , Sun Hanwen , Kong Xiang Zheng , Fu Chunhua , Cui Shuqin , Zhang Zhiqin
Published: March 2015

Pure polymer microspheres with undoped methacrylate monomers were prepared and firstly applied as organic fillers for dental restorative materials.
Green synthesis, photocatalytic and photoelectrochemical performance of an Au–Graphene nanocomposite
Authors: Khan Mohammad Ehtisham , Khan Mohammad Mansoob , Cho Moo Hwan
Published: March 2015

Visible light-induced photocatalytic degradation of pollutants using an Au–Graphene nanocomposite.
Effect of organic solvent and Brønsted acid on 5-hydroxymethylfurfural preparation from glucose over CrCl3
Authors: Yang Yan , Liu Wentao , Wang Ningning , Wang Haijun , Song Zhanxin , Li Wei
Published: March 2015

An investigation of the effect of solvent and Brønsted acid on the mechanism of 5-hydroxymethylfurfural preparation from glucose over CrCl3by experimental and computational study.
Conversion of fructose into 5-HMF: a study on the behaviour of heterogeneous cerium-based catalysts and their stability in aqueous media under mild conditions
Authors: Dibenedetto Angela , Aresta Michele , Pastore Carlo , di Bitonto Luigi , Angelini Antonella , Quaranta Eugenio
Published: March 2015

In this paper, we present the results of a study on 5-HMF production from fructose by means of heterogeneous catalysts in aqueous media.
Ball flower like manganese, strontium substituted hydroxyapatite/cerium oxide dual coatings on the AZ91 Mg alloy with improved bioactive and corrosion resistance properties for implant applications
Authors: Gopi D. , Murugan N. , Ramya S. , Shinyjoy E. , Kavitha L.
Published: March 2015

Mn, Sr-HAP/CeO2dual layer coated AZ91 Mg alloy will be a revolutionary potential material for orthopedic implants.
Stereocontrolled 1,2-cis glycosylation as the driving force of progress in synthetic carbohydrate chemistry
Authors: Nigudkar Swati S. , Demchenko Alexei V.
Published: March 2015

Recent developments in stereoselective 1,2-cisglycosylation that have emerged during the past decade are surveyed herein.
Et3B-mediated two- and three-component coupling reactions via radical decarbonylation of α-alkoxyacyl tellurides: single-step construction of densely oxygenated carboskeletons
Authors: Nagatomo Masanori , Kamimura Daigo , Matsui Yuki , Masuda Keisuke , Inoue Masayuki
Published: March 2015

We devised new radical-based two- and three-component coupling reactions of sugar derivatives, and realized one-step construction of contiguously substituted polyol structures.
Hierarchical donut-shaped LiMn2O4as an advanced cathode material for lithium-ion batteries with excellent rate capability and long cycle life
Authors: Sun Weiwei , Liu Huiqin , Peng Tao , Liu Yumin , Bai Gongxun , Kong Sen , Guo Shishang , Li Meiya , Zhao Xing-Zhong
Published: March 2015

In this work, we have demonstrated a facile approach to synthesize donut-shaped LiMn2O4comprising interpenetrating nanograins, and this material demonstrates excellent high-rate cycling reversibility.
Zn–Fe–ZIF-derived porous ZnFe2O4/C@NCNT nanocomposites as anodes for lithium-ion batteries
Authors: Wu Jiafeng , Song Yonghai , Zhou Rihui , Chen Shouhui , Zuo Li , Hou Haoqing , Wang Li
Published: March 2015

A promising anode material for LIBs was constructed based on the novel porous ZnFe2O4/C@NCNTs through a one-step pyrolysis of Zn–Fe–ZIF.
Pre-coating layered double hydroxide nanoparticles with albumin to improve colloidal stability and cellular uptake
Authors: Gu Zi , Zuo Huali , Li Li , Wu Aihua , Xu Zhi Ping
Published: March 2015

We introduced a new strategy of albumin pre-coating to effectively stabilise layered double hydroxide (LDH) nanoparticles for biomedical applications.
Solution-processed sodium hydroxide as the electron injection layer in inverted bottom-emission organic light-emitting diodes
Authors: Wang Danbei , Wu Yuanwu , Bi Ran , Zhang Hongmei , Zhao Dewei
Published: March 2015

Thin sodium hydroxide treated by blowing CO2 and water vapor in inverted organic light-emitting diodes exhibits improved efficiency.
Protein stability versus function: effects of destabilizing missense mutations on BRCA1 DNA repair activity
Authors: Gaboriau David C.A. , Rowling Pamela J.E. , Morrison Ciaran G. , Itzhaki Laura S.
Published: March 2015

Mutations in breast cancer susceptibility gene BRCA1 (breast cancer early-onset 1) are associated with increased risk of developing breast and ovarian cancers. BRCA1 is a large protein of 1863 residues with two small structured domains at its termini: a RING domain at the N-terminus and a BRCT (BRCA1 C-terminus domain) repeat domain at the C-terminus. Previously, we quantified the effects of missense mutations on the thermodynamic stability of the BRCT domains, and we showed that many are so destabilizing that the folded functional state is drastically depopulated at physiological temperature. In the present study, we ask whether and how reduced thermodynamic stability of the isolated BRCT mutants translates into loss of function of the full-length protein in the cell. We assessed the effects of missense mutants on different stages of BRCA1-mediated DNA repair by homologous recombination using chicken lymphoblastoid DT40 cells as a model system. We found that all of the mutations, regardless of how profound their destabilizing effects, retained some DNA repair activity and thereby partially rescued the chicken BRCA1 knockout. By contrast, the mutation R1699L, which disrupts the binding of phosphorylated proteins (but which is not destabilizing), was completely inactive. It is likely that both protein context (location of the BRCT domains at the C-terminus of the large BRCA1 protein) and cellular environment (binding partners, molecular chaperones) buffer these destabilizing effects such that at least some mutant protein is able to adopt the folded functional state.
SWIPT for wireless cooperative networks
Authors: Chu Zheng , Johnston Martin , Le Goff Stéphane
Published: March 2015

Simultaneous wireless information and power transfer (SWIPT) in wireless cooperative networks is studied, where multiple source–destination pairs establish a communication link via an energy harvesting (EH) relay. The relay employs a power splitting (PS) scheme to harvest the energy sent from each source, which it uses to forward the transmissions to the destinations. The total transmission rate maximisation problem is investigated subject to transmit power and EH constraints, which can be divided into each source–destination node’s transmission rate based on a non‐cooperative transmission strategy. This problem is addressed to obtain the optimal PS ratio and power allocation, and derive a closed‐form solution. Numerical results are also provided to validate the performance of this proposed scheme, which outperforms a scheme with a uniform PS ratio.
Geometric dilution of precision for bearing‐only passive location in three‐dimensional space
Authors: Zhong Yu , Wu Xiao Yan , Huang Shu Cai
Published: March 2015

Geometric dilution of precision (GDOP) is a measurement of localisation accuracy in bearing‐only passive location. However, the current GDOP expression is available only for two dimensions; while GDOP is widely adopted in spatial application, consequently, the explicit GDOP expression in three‐dimensional (3D) space using the Cauchy‐Binet formula is derived. The derived GDOP expression is used in two examples, which shows that the localisation accuracy is affected by both the number of sensors and the observation geometry.
Box‐folded four‐element MIMO antenna system for LTE handsets
Authors: Yang Lingsheng , Li Tao
Published: March 2015

A multiple‐input–multiple‐output (MIMO) antenna system for mobile handsets is presented. The proposed MIMO system consists of four identical box‐folded planar inverted‐F antenna. A broad operating band (1.84–2.69 GHz) with overall MIMO system dimensions of 136 × 68.8 × 6 mm3 and an element size of only 10 × 10 × 5 mm3 can be achieved. Lower than −14.2 dB isolation between any two of the elements has been obtained at the whole operating band. The correlation coefficient, radiation pattern and antenna gain are also studied.
Prediction unit pruning algorithm for inter‐prediction in high‐efficiency video coding
Authors: Kang Donggil , Park Sangsoo , Hong Youpyo
Published: March 2015

Inter‐prediction in high‐efficiency video coding (HEVC) provides higher coding efficiency at the expense of increased computational complexity compared with previous video coding standards. Presented is an efficient inter‐prediction algorithm based on prediction unit pruning to reduce the computational load. Experimental results show that the proposed algorithm achieves about 11% additional reduction in the inter‐mode decision time when applied to a coding unit pruning algorithm.
Low‐power, high‐speed dual modulus prescalers based on branch‐merged true single‐phase clocked scheme
Authors: Jia Song , Yan Shilin , Wang Yuan , Zhang Ganggang
Published: March 2015

A new design scheme intended to improve the performance of true single‐phase clocked (TSPC) dual modulus prescalers is presented. Two branches of TSPC D flip‐flops are merged to reduce both power and device count. An HSPICE simulation of the proposed scheme demonstrates the highest power efficiency and best power–delay product among the referenced designs.
Rapid wide‐field heterodyne interferometry with custom 2D CMOS camera
Authors: Zhang J. , See C.W. , Smith R.J. , Johnston N.S. , Pitter M.C. , Somekh M.G. , Light R.A.
Published: March 2015

A wide‐field pseudo‐heterodyne interference contrast microscope is described, which employs a complementary metal–oxide semiconductor (CMOS) phase‐sensitive camera. The use of multiple wells in the camera enables extremely rapid measurement of a full phase field at high resolution and the modulation frequency is not limited by the camera frame rate. The high data acquisition frequency allows the effects of microphonics to be frozen to mitigate the effect of low‐frequency disturbance.
Scene text detection method based on the hierarchical model
Authors: Zhou Gang , Liu Yuehu , Xu Liang , Jia Zhenhong
Published: March 2015

As an important step in text‐based information extraction systems, scene text detection has become a popular subject of research in recent years. In this study, the authors present a novel approach to robustly detect texts which are variable in scales, colours, fonts, languages and orientations in scene images. To segment candidate text connected components (CCs) from images, both local contrast and colour consistency are considered in superpixel level. To filter out the non‐text CCs, a hierarchical model is designed. This hierarchical model groups the CCs into three cascaded stages, and is equipped with a well‐designed classifier in each stage. Experimental results on the public ICDAR 2005 dataset and the MSRA‐TD500 dataset show that their approach obtains better performance than other state‐of‐the‐art methods.
Grafting pH‐sensitive poly[2‐(diethylamino)ethyl methacrylate] modification of vesicular silica with activator regenerated by electron transfer atom transfer radical polymerisation for controlled drug release
Authors: Liu Fangfang , Zhang Yan , Zhou Guowei
Published: March 2015

pH‐sensitive poly[2‐(diethylamino)ethyl methacrylate]‐modified vesicular silica (VS‐PDEAEMA) is prepared in different amounts of 2‐(diethylamino)ethyl methacrylate via activators regenerated by electron transfer for atom transfer radical polymerisation. The pH‐responsive polymer is successfully grafted onto the shell of vesicular silica (VS) and then characterised. The inner PDEAEMA layer became thick, while the outmost polymer thickness did not change as the monomer amount was increased. Pure VS and VS‐PDEAEMA are employed as supports for the loading and release of captopril. The release profiles of the captopril‐loaded samples are studied in phosphate buffer solution with different pH values (4.0, 6.0 and 7.4). The captopril release rate can be controlled by PDEAEMA‐functionalised carriers. Moreover, 31.5 and 70.0 wt% of captopril is released from the grafted polymer at pH 7.4 and 4.0, respectively. The modified VS can have potential applications in targeted drug delivery systems.
From simplicial Chern-Simons theory to the shadow invariant I
Authors: Hahn Atle
Published: March 2015

This is the first of a series of papers in which we introduce and study a rigorous “simplicial” realization of the non-Abelian Chern-Simons path integral for manifolds M of the form M = Σ × S1 and arbitrary simply connected compact structure groups G. More precisely, we will introduce, for general links L in M, a rigorous simplicial version WLOrig(L) of the corresponding Wilson loop observable WLO(L) in the so-called “torus gauge” by Blau and Thompson [Nucl. Phys. B 408(2), 345–390 (1993)]. For a simple class of links L, we then evaluate WLOrig(L) explicitly in a non-perturbative way, finding agreement with Turaev’s shadow invariant L.
Eggs and milk: Spinning spheres partially immersed in a liquid bath
Authors: Langley Kenneth R. , Maynes Daniel , Truscott Tadd T.
Published: March 2015

When a hard-boiled egg spins through a pool of milk on the kitchen counter, the milk rises up the sides of the egg and droplets are ejected. This phenomenon occurs when any partially submerged object whose radius increases upward from the fluid surface (e.g., spheres, inverted cones, and rings) spins in a liquid bath. The fluid ejects from the surface near the maximum radius in one of three ejection modes: jets, sheets, or sheet breakup. Additionally, a surprisingly large flow rate is induced by the spinning object. In this study, we used spheres to determine the effects of experimental parameters on the induced flow rate. We characterized the modes of ejection and measured the sheet breakup distance using high-speed imaging. The basis of our closed form analytical model utilizes an integral momentum boundary layer analysis both beneath the free surface and in the thin film attached to the sphere. We present criteria defining the transitions between ejection modes and the radius where liquid sheets break up in the sheet ejection regime. Criteria defining the transitions between ejection modes and the radius where liquid sheets break up in the sheet ejection regime shows good agreement with experiments.
Dispersion characteristics of planar grating with arbitrary grooves for terahertz Smith-Purcell radiation
Authors: Cao Miaomiao , Liu Wenxin , Wang Yong , Li Ke
Published: March 2015

In this paper, a novel method of getting the dispersion relations in planar grating with arbitrary grooves for terahertz Smith-Purcell radiation is investigated analytically. The continuous profile of the groove is approximately replaced by a series of rectangular steps. By making use of field matches method and the continuity of transverse admittance, the universal dispersion equation for grating with arbitrarily shaped grooves is derived. By solving the dispersion equation in presence of electron beam, the growth rate is obtained directly and the dependence on beam parameters is analyzed. Comparisons of the dispersion characteristics among some special groove shapes have been made by numerical calculation. The results show that the rectangular-step approximation method provides a novel approach to obtain the universal dispersion relation for grating with arbitrary grooves for Smith-Purcell radiation.
A droplet deformation and breakup model based on virtual work principle
Authors: Sichani Arash B. , Emami Mohsen D.
Published: March 2015

A new method of modeling the deformation and secondary breakup of a droplet is presented. The general formulation is based on the virtual work principle and potential flow assumption. To reach the final model, some approximations are made in the aerodynamic calculations including moderate Reynolds number of gas, Reg ∼ 1000, and high density ratio of liquid to gas phase, ρl/ρg ≫ 1. The dynamics of a drop is considered using two degrees of freedom. Two coupled ordinary differential equations are derived which describe time evolution of drop within both vibrational and bag regimes. The model is capable of keeping track of droplet deformation and distortion up to the onset of the bag rupture. The critical Weber number has been predicted with an error of around 20% as compared to the experimental data. The model performance is enhanced after a minor tuning, which result in the critical Weber number of 12.5. The predicted distortion quantities in lateral and longitudinal directions, as well as the drop profiles, are validated against experiments for bag and vibrational regimes. A good agreement is found between the computed results and experiments. Overall, achievements of the present work indicate a promising potential of the current approach for modeling droplet dynamics.
Magnetic field directed assembly of superstructures of ferrite-ferroelectric core-shell nanoparticles and studies on magneto-electric interactions
Authors: Srinivasan G. , Sreenivasulu G. , Benoit Crystal , Petrov V. M. , Chavez F.
Published: March 2015

Composites of ferromagnetic and ferroelectric are of interest for studies on mechanical strain mediated magneto-electric (ME) interactions and for useful technologies. Here, we report on magnetic-field-assisted-assembly of barium titanate (BTO)-nickel ferrite (NFO) core-shell particles into linear chains and 2D/3D arrays and measurements of ME effects in such assemblies. First, we synthesized the core-shell nano-particles with 50–600 nm BTO and 10–200 nm NFO by chemical self-assembly by coating the ferroic particles with complementary coupling groups and allowing them to self-assemble in the presence of a catalyst via the “click” reaction. The core-shell structure was confirmed with electron microscopy and scanning probe microscopy. We obtained superstructure of the core-shell particles by subjecting them to a magnetic field gradient that exerts an attractive force on the particles and align them toward the regions of high field strengths. At low particle concentration, linear chains were formed and they evolved into 2D and 3D arrays at high particle concentrations. Magnetoelectric characterization on unassembled films and assembled arrays has been performed through measurements of low-frequency ME voltage coefficient (MEVC) by subjecting the sample to a bias magnetic field and an ac magnetic field. The MEVC is higher for field-assembled samples than for unassembled films and is found to be sensitive to field orientation with a higher MEVC for magnetic fields parallel to the array direction than for magnetic fields perpendicular to the array. A maximum MEVC of 20 mV/cm Oe, one of the highest reported for any bulk nanocomposite, is measured across the array thickness. A model is provided for ME coupling in the superstructures of BTO-NFO particulate composites. First, we estimated the MEVC for a free-standing BTO-NFO core-shell particle and then extended the model to include an array of linear chains of the particles. The theoretical estimates are in qualitative agreement with the data.
Heterojunction metal-oxide-metal Au-Fe3O4-Au single nanowire device for spintronics
Authors: Reddy K. M. , Padture Nitin P. , Punnoose Alex , Hanna Charles
Published: March 2015

In this report, we present the synthesis of heterojunction magnetite nanowires in alumina template and describe magnetic and electrical properties from a single nanowire device for spintronics applications. Heterojunction Au-Fe-Au nanowire arrays were electrodeposited in porous aluminum oxide templates, and an extensive and controlled heat treatment process converted Fe segment to nanocrystalline cubic magnetite phase with well-defined Au-Fe3O4 interfaces as confirmed by the transmission electron microscopy. Magnetic measurements revealed Verwey transition shoulder around 120 K and a room temperature coercive field of 90 Oe. Current–voltage (I-V) characteristics of a single Au-Fe3O4-Au nanowire have exhibited Ohmic behavior. Anomalous positive magnetoresistance of about 0.5% is observed on a single nanowire, which is attributed to the high spin polarization in nanowire device with pure Fe3O4 phase and nanocontact barrier. This work demonstrates the ability to preserve the pristine Fe3O4 and well defined electrode contact metal (Au)–magnetite interface, which helps in attaining high spin polarized current.
Structural and magnetic properties of FeNi thin films fabricated on amorphous substrates
Authors: Tashiro T. Y. , Mizuguchi M. , Kojima T. , Koganezawa T. , Kotsugi M. , Ohtsuki T. , Takanashi K.
Published: March 2015

FeNi films were fabricated by sputtering and rapid thermal annealing on thermally amorphous substrates to realize the formation of an L10-FeNi phase by a simple method. Structural and magnetic properties of FeNi films were investigated by varying the annealing temperature. L10-FeNi superlattice peaks were not observed in X-ray diffraction patterns, indicating no formation of L10-ordered phase, however, the surface structure systematically changed with the annealing temperature. Magnetization curves also revealed a drastic change depending on the annealing temperature, which indicates the close relation between the morphology and magnetic properties of FeNi films fabricated on amorphous substrates.
Energy barrier analysis of Nd-Fe-B thin films
Authors: Goto R. , Okamoto S. , Kikuchi N. , Kitakami O.
Published: March 2015

The magnetization reversal mechanism of a permanent magnet has long been a controversial issue, which is closely related to the so-called coercivity problem. It is well known that the energy barrier for magnetization reversal contains essential information on reversal process. In this study, we propose a method to analyze the energy barrier function for the magnetization reversal. Preferentially (001) oriented Nd-Fe-B films with and without a Nd overlayer are used as model magnets. By combining the magnetic viscosity and time dependent coercivity measurements, the barrier function has been successfully evaluated. As a result, although the Nd-Fe-B films with and without Nd overlayer exhibit different magnetic behaviors, the power indices for their energy barrier are almost the same, suggesting that the magnetization reversal proceeds in a similar mode.
Exploring electrical conductivity anomalies across the martensite transition in Fe7Pd3 ferromagnetic shape memory alloys: Experiments and ab-initio calculations
Authors: Arabi-Hashemi A. , Mayr S. G.
Published: March 2015

Conductivity in Fe7Pd3 is characterized by an anomalous increase when traversing the face–centered–cubic (fcc) austenite to face–centered–tetragonal (fct) martensite transition, contrary to most other conventional and ferromagnetic shape memory alloys. Experiments on molecular– beam–epitaxy–grown single crystals indicate a resistivity change of ≈20% during the transformation on top of a quadratic temperature dependence reaching up to room temperature. The physical foundations of residual resistivity changes along the full Bain path are addressed by a Kubo– Greenwood approach within the framework of density functional theory. To do so, a concept to reliably extract the DC conductivities is proposed that yields reproducible results consistent with experiments. Finding that conductivity peaks in the fct phase, we identify a large density of states paired with high velocities at the Fermi level in the majority spin sub–bands in presence of minimum s–d electron scattering as underlying physical origin.
Dipole-dipole interaction and its concentration dependence of magnetic fluid evaluated by alternating current hysteresis measurement
Authors: Ota Satoshi , Yamada Tsutomu , Takemura Yasushi
Published: March 2015

Magnetic nanoparticles (MNPs) are used as therapeutic and diagnostic tools, such as for treating hyperthermia and in magnetic particle imaging, respectively. Magnetic relaxation is one of the heating mechanisms of MNPs. Brownian and Néel relaxation times are calculated conventional theories; however, the influence of dipole–dipole interactions has not been considered in conventional models. In this study, water-dispersed MNPs of different concentrations and MNPs fixed with an epoxy bond were prepared. dc and ac hysteresis loops for each sample were measured. With respect to both dc and ac hysteresis loops, magnetization decreased with the increase in MNP concentration because of inhibition of magnetic moment rotation due to dipole–dipole interactions. Moreover, intrinsic loss power (ILP) was estimated from the areas of the ac hysteresis loops. The dependence of ILP on the frequency of the magnetic field was evaluated for each MNP concentration. The peak frequency of ILP increased with the decrease in MNP concentration. These peaks were due to Brownian relaxation, as they were not seen with the fixed sample. This indicates that the Brownian relaxation time became shorter with lower MNP concentration, because the weaker dipole–dipole interactions with lower concentrations suggested that the magnetic moments could rotate more freely.
Formation of BiFeO3(110) films on ferromagnetic CoPt(111) electrode layer on glass substrates at reduced temperatures
Authors: Chang H. W. , Yuan F. T. , Yu Y. C. , Tu S. Y. , Lin P. C. , Wang C. R. , Yang A. B. , Tu C. S. , Jen S. U.
Published: March 2015

Structure, ferroelectric, and magnetic properties of BiFeO3 (110) films grown on 20-nm-thick ferromagnetic CoPt(111) buffered glass substrate at 350–550 °C have been studied. (110)-texture of BFO films is developed at the reduced temperature as low as 400–550 °C, but isotropic orientation is found at higher temperature of 600 °C. Low temperature deposition results in dense microstructure, fine grains, and smooth surface morphology, which are favorable for applications. BFO(110) films on CoPt(111) underlayer exhibit desired ferroelectric and magnetic properties. Electrical polarization (2Pr) of 96–137 μC/cm2 and coercive field (Ec) of 495–618 kV/cm for studied BFO (110) films are comparable to those grown on single crystal substrates. Moreover, exchange bias between BFO and CoPt is observed after a field cooling from 370 °C to room temperature (RT) at 2 kOe. Large exchange bias field of 155 Oe at RT and coercivity of 1631 Oe are obtained. The presented results provide useful information for the applications based on electric-magnetic interactions.
Low-temperature spray-deposited indium oxide for flexible thin-film transistors and integrated circuits
Authors: Petti Luisa , Faber Hendrik , Münzenrieder Niko , Cantarella Giuseppe , Patsalas Panos A. , Tröster Gerhard , Anthopoulos Thomas D.
Published: March 2015

Indium oxide (In2O3) films were deposited by ultrasonic spray pyrolysis in ambient air and incorporated into bottom-gate coplanar and staggered thin-film transistors. As-fabricated devices exhibited electron-transporting characteristics with mobility values of 1 cm2V−1s−1 and 16 cm2V−1s−1 for coplanar and staggered architectures, respectively. Integration of In2O3 transistors enabled realization of unipolar inverters with high gain (5.3 V/V) and low-voltage operation. The low temperature deposition (≤250 °C) of In2O3 also allowed transistor fabrication on free-standing 50 μm-thick polyimide foils. The resulting flexible In2O3 transistors exhibit good characteristics and remain fully functional even when bent to tensile radii of 4 mm.
Intense isolated attosecond pulse generation from relativistic laser plasmas using few-cycle laser pulses
Authors: Ma Guangjin , Dallari William , Borot Antonin , Krausz Ferenc , Yu Wei , Tsakiris George D. , Veisz Laszlo
Published: March 2015

We have performed a systematic study through particle-in-cell simulations to investigate the generation of attosecond pulse from relativistic laser plasmas when laser pulse duration approaches the few-cycle regime. A significant enhancement of attosecond pulse energy has been found to depend on laser pulse duration, carrier envelope phase, and plasma scale length. Based on the results obtained in this work, the potential of attaining isolated attosecond pulses with ∼100 μJ energy for photons >16 eV using state-of-the-art laser technology appears to be within reach.
Terahertz electromodulation spectroscopy of electron transport in GaN
Authors: Engelbrecht S. G. , Arend T. R. , Zhu T. , Kappers M. J. , Kersting R.
Published: March 2015

Time-resolved terahertz (THz) electromodulation spectroscopy is applied to investigate the high-frequency transport of electrons in gallium nitride at different doping concentrations and densities of threading dislocations. At THz frequencies, all structures reveal Drude transport. The analysis of the spectral response provides the fundamental transport properties, such as the electron scattering time and the electrons' conductivity effective mass. We observe the expected impact of ionized-impurity scattering and that scattering at threading dislocations only marginally affects the high-frequency mobility.
Excellent wear life of silicon nitride/tetrahedral amorphous carbon bilayer overcoat on functional tape heads
Authors: Yeo Reuben J. , Dwivedi Neeraj , Tripathy S. , Bhatia C. S.
Published: March 2015

Developing ultrathin and highly wear-resistant overcoats for magnetic tape heads is one of the current research areas of interest, because of its potential to delay pole tip recession and increase the operational lifetime of high areal density tape drives. Using optimized process conditions and an appropriate overcoat design, we report on the development of a ∼20 nm thick silicon nitride/tetrahedral amorphous carbon (Si/SiNx/ta-C) bilayer overcoat, where the ta-C film was deposited by a filtered cathodic vacuum arc process. The bilayer overcoat deposited on a functional tape head survived 40–50 × 106 m of testing with commercial tape media under standard industrial testing conditions. The excellent wear resistance of the overcoat was attributed to the generation of high (∼72%) sp3 carbon content and the formation of strong interfacial bonds, such as Si-C, C=N, nitrile, and (Al, Ti)N at the interfaces, as confirmed by various spectroscopic techniques. This study demonstrates the pivotal role of high sp3 carbon bonding combined with enhanced interfacial bonding in developing an ultrathin yet durable protective overcoat for magnetic tape heads.
Zero-field spin torque oscillation in Co2(Fe, Mn)Si with a point contact geometry
Authors: Yamamoto T. , Seki T. , Kubota T. , Yako H. , Takanashi K.
Published: March 2015

We show spin torque oscillation at zero external magnetic field using a point-contact giant magnetoresistance device with a highly spin-polarized Co2Fe0.4Mn0.6Si (CFMS) Heusler alloy. The device emitted a high rf power (Prf) signal with a narrow spectral linewidth of 3 MHz without external magnetic field. Depending on the applied current, mode changes were clearly observed, and a large Prf of 25.7 nW was achieved. The large Prf and the high coherency of oscillation are attributable to the combination of the high spin-polarization of CFMS and the advantages of point-contact geometry.
Investigations on Ni-Co-Mn-Sn thin films: Effect of substrate temperature and Ar gas pressure on the martensitic transformations and exchange bias properties
Authors: Machavarapu Ramudu , Jakob Gerhard
Published: March 2015

We report the effect of substrate temperature (TS) and Ar gas pressure (PD) on the martensitic transformations, magnetic and exchange bias (EB) properties in Heusler type Ni-Co-Mn-Sn epitaxial thin films. Martensitic transformation temperatures and EB fields at 5 K were found to increase with increasing TS. The observed maximum EB value of 320 Oe after field cooling in the film deposited at 650 ∘C is high among the values reported for Ni-Mn-Sn thin films which is attributed to the coexistence of ferromagnetic (FM) and antiferromagnetic (AF) phases in the martensitic state. In the case of PD variation, with increase in PD, martensitic transformation temperatures were increased and a sharp transformation was observed in the film deposited at 0.06 mbar. Magnetization values at 5 K were higher for increasing PD. These observations are attributed to the compositional shift. EB effect is also present in these films. Microstructural features observed using atomic force microscopy (AFM) shows a fine twinning and reduced precipitation with increase in PD, which is also confirmed from the scanning electron microscopy (SEM) images. EB effects in both series were confirmed from the training effect. Target ageing effect has been observed in the films deposited before and after ninety days of time interval. This has been confirmed both on substrate temperature and Ar gas pressure variations.
Unipolar resistive switching in planar Pt/BiFeO3/Pt structure
Authors: Katiyar Rajesh K. , Sharma Yogesh , Barrionuevo Diestra Danilo G. , Misra Pankaj , Kooriyattil Sudheendran , Pavunny Shojan P. , Morell Gerardo , Weiner Brad R. , Scott J. F. , Katiyar Ram S.
Published: March 2015

We report unipolar resistive switching suitable for nonvolatile memory applications in polycrystalline BiFeO3 thin films in planar electrode configuration with non-overlapping Set and Reset voltages, On/Off resistance ratio of ∼104 and good data retention (verified for up to 3,000 s). We have also observed photovoltaic response in both high and low resistance states, where the photocurrent density was about three orders of magnitude higher in the low resistance state as compared to the high resistance state at an illumination power density of ∼100 mW/cm2. Resistive switching mechanisms in both resistance states of the planar device can be explained by using the conduction filament (thermo-chemical) model.
High brightness angled cavity quantum cascade lasers
Authors: Heydari D. , Bai Y. , Bandyopadhyay N. , Slivken S. , Razeghi M.
Published: March 2015

A quantum cascade laser (QCL) with an output power of 203 W is demonstrated in pulsed mode at 283 K with an angled cavity. The device has a ridge width of 300 μm, a cavity length of 5.8 mm, and a tilt angle of 12°. The back facet is high reflection coated, and the front facet is anti-reflection coated. The emitting wavelength is around 4.8 μm. In distinct contrast to a straight cavity broad area QCL, the lateral far field is single lobed with a divergence angle of only 3°. An ultrahigh brightness value of 156 MW cm−2 sr−1 is obtained, which marks the brightest QCL to date.
Mechanically stretchable and tunable metamaterial absorber
Authors: Zhang Fuli , Feng Shuqi , Qiu Kepeng , Liu Zijun , Fan Yuancheng , Zhang Weihong , Zhao Qian , Zhou Ji
Published: March 2015

In this letter, we present experimental demonstration of a mechanically stretchable and tunable metamaterial absorber composed of dielectric resonator stacked on a thin conductive rubber layer. A near unity absorption is observed due to strong local field confinement around magnetic Mie resonance of dielectric resonator. Furthermore, the interspacing between unit cells is modulated dynamically under uniaxial stress. Owing to the decreases of longitudinal coupling between neighboring unit cells, the resonant absorption peak is reversibly tuned by 410 MHz, as the stain varies up to 180% along H field direction. On the contrary, the resonant absorption state is nearly independent on strain variation when external stress is applied along E field direction, due to the weak transverse interplaying. The mechanically tunable metamaterial absorber featured by flexibility paves a way forwards for actual application.
Potential of compost tea for suppressing plant diseases.
Authors: St. Martin C. C. G.
Published: March 2015

Numerous studies have demonstrated that water-based compost preparations, referred to as compost tea and compost-water extract, can suppress phytopathogens and plant diseases. Despite its potential, compost tea has generally been considered as inadequate for use as a biocontrol agent in conventional cropping systems but important to organic producers who have limited disease control options. The major impediments to the use of compost tea have been the less-than-desirable and inconsistent levels of plant disease suppression as influenced by compost tea production and application factors including compost source and maturity, brewing time and aeration, dilution and application rate and application frequency. Although the mechanisms involved in disease suppression are not fully understood, sterilization of compost tea has generally resulted in a loss in disease suppressiveness. This indicates that the mechanisms of suppression are often, or predominantly, biological, although physico-chemical factors have also been implicated. Increasing the use of molecular approaches, such as metagenomics, metaproteomics, metatranscriptomics and metaproteogenomics should prove useful in better understanding the relationships between microbial abundance, diversity, functions and disease suppressive efficacy of compost tea. Such investigations are crucial in developing protocols for optimizing the compost tea production process so as to maximize disease suppressive effect without exposing the manufacturer or user to the risk of human pathogens. To this end, it is recommended that compost tea be used as part of an integrated disease management system.
The heritage of autonomy in Carpathian Rus' and Ukraine's Transcarpathian region
Authors: Magocsi Paul Robert
Published: March 2015

As the Soviet Union disintegrated and eventually dissolved in 1991, many of its peoples, both so-called titular nationalities and national minorities, put forth demands for independence or, at the very least, self-rule for territories that were said to represent the national patrimony. Among the many peoples who put forward such demands were Carpatho-Rusyns, who, together with fellow citizens of other national backgrounds, demanded autonomy or self-rule for the region (oblast) of Transcarpathia in far western Ukraine. This essay examines from a historical perspective the question of autonomy or self-rule for Carpatho-Rusyns and for all or part of the territory they inhabit, historic Carpathian Rus'. The autonomy question in Carpathian Rus' is hardly new, but one that goes as far back as 1848.
Immune-modulating activities of polysaccharides extracted from brown algae Hizikia fusiforme
Authors: Jeong Sang Chul , Jeong Yong Tae , Lee Sang Myung , Kim Jin Hee
Published: March 2015

The immuno-modulating activities of seaweed (Hizikia fusiforme) extracts on murine macrophage and splenocyte were studied in vitro. Polysaccharide (HFP) exhibited the potential macrophage stimulating effects than water extract (HFW) such as NO production and enhanced pro-inflammatory cytokines on the Raw 264.7 cells and splenocytes. From the mono-sugar composition, HFP-associated fucose based on HFP of H. fusiforme acts as immune modulator.
Performance of and methanogenic communities involved in an innovative anaerobic process for the treatment of food wastewater in a pilot plant
Authors: Lee Seungyong , Lee Bowon , Han Gyuseong , Yoon Heechul , Kim Woong
Published: March 2015

In this study, dual-cylindrical anaerobic digesters were designed and built on the pilot plant scale for the improvement of anaerobic digestion efficiency. The removal efficiency of organics, biogas productivity, yield, and microbial communities was evaluated as performance parameters of the digester. During the stable operational period in the continuous mode, the removal efficiencies of chemical oxygen demand and total solids were 74.1 and 65.1%, respectively. Biogas productivities of 63.9 m3/m3-FWW and 1.3 m3/kg-VSremoved were measured. The hydrogenotrophic methanogen orders, Methanomicrobiales and Methanobacteriales, were predominant over the aceticlastic methanogen order, Methanosarcinaceae, probably due to the tolerance of the hydrogenotrophs to environmental perturbation in the field and their faster growth rate compared with that of the aceticlastics.