bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional carbon nanotubes for high-quality charge transfer and moisture regulation through membranes: structural and functional insights
Authors: Gugliuzza Annarosa , Pingitore Valentino , Miriello Domenico , Drioli Enrico
Published: April 2015

Electrically-responsive breathable membranes through which assisted charge and moisture transport are achieved by selective donor–acceptor-site interactions involving functional carbon nanotubes.
Infrared spectra of small anionic water clusters from density functional theory and wavefunction theory calculations
Authors: Gong Zu-Yong , Duan Sai , Tian Guangjun , Jiang Jun , Xu Xin , Luo Yi
Published: April 2015

We performed systematic theoretical studies on small anionic water/deuterated water clusters W/D−n=2–6 at both density functional theory (B3LYP) and wavefunction theory (MP2) levels.
Low-temperature CO oxidation on CuO/CeO2catalysts: the significant effect of copper precursor and calcination temperature
Authors: Sun Shuaishuai , Mao Dongsen , Yu Jun , Yang Zhiqiang , Lu Guanzhong , Ma Zhen
Published: April 2015

The performance of CuO/CeO2catalysts for CO oxidation strongly depends on the type of copper precursor and the calcination temperature.
Simulated sunlight photocatalytic degradation of aqueous p-nitrophenol and bisphenol A in a Pt/BiOBr film-coated quartz fiber photoreactor
Authors: Jia Yanqin , Yang Yuxin , Guo Yingna , Guo Wan , Qin Qin , Yang Xia , Guo Yihang
Published: April 2015

Pt/BiOBr film-coated quartz fiber bundles were prepared by dip-coating combined with photodeposition, and their phase and chemical structures, electronic and optical properties, textural properties as well as morphologies were well-characterized.
Aza-nickelacycle key intermediate in nickel(0)-catalyzed transformation reactions
Authors: Ohashi Masato , Hoshimoto Yoichi , Ogoshi Sensuke
Published: April 2015

Oxidative cyclization of alkynes and imines with nickel(0) is a key step in multicomponent coupling and cycloaddition reactions to give nitrogen-containing organic compounds.
Mechanistic insights into the full hydrogenation of 2,6-substituted pyridine catalyzed by the Lewis acid C6F5(CH2)2B(C6F5)2
Authors: Zhao Jiyang , Wang Guoqiang , Li Shuhua
Published: April 2015

A computational study indicates that the pyridinium hydridoborate ion pair is the key intermediate for the full hydrogenation of 2,6-substituted pyridine catalyzed by the Lewis acid C6F5(CH2)2B(C6F5)2.
Strong effect of copper(ii) coordination on antiproliferative activity of thiosemicarbazone–piperazine and thiosemicarbazone–morpholine hybrids
Authors: Bacher Felix , Dömötör Orsolya , Chugunova Anastasia , Nagy Nóra V. , Filipović Lana , Radulović Siniša , Enyedy Éva A. , Arion Vladimir B.
Published: April 2015

Strong enhancement of antiproliferative activity in human cancer cell lines was found upon coordination of new hybrid ligands to copper(ii).
Potassium induced stitching of a flexible tripodal ligand into a bi-metallic two-dimensional coordination polymer for photo-degradation of organic dyes
Authors: Bhardwaj Vimal K.
Published: April 2015

A novel strategy for the stitching of a flexible tripodal ligand into a bimetallic two-dimensional coordination polymer was developed for photo-degradation of dyes.
Cyanide free contraction of disclosed 1,4-dioxane ring as a route to cobalt bis(dicarbollide) derivatives with short spacer between the boron cage and terminal functional group
Authors: Shmal'ko Akim V. , Stogniy Marina Yu. , Kazakov Grigorii S. , Anufriev Sergey A. , Sivaev Igor B. , Kovalenko Leonid V. , Bregadze Vladimir I.
Published: April 2015

The 1,4-dioxane derivative of cobalt bis(dicarbollide) reacts with dialkylsulfides and triphenylphosphine to give the corresponding sulfonium and phosphonium derivatives.
Chemical components from the haulm of Artemisia selengensis and the inhibitory effect on glycation of β-lactoglobulin
Authors: Li Xiaoming , Lu Yonglin , Deng Ronghua , Zheng Tiesong , Lv Lishuang
Published: April 2015

Artemisia selengensis (AS) has been traditionally used as both food and medicine for thousands of years in China.
A laser induced breakdown spectroscopy quantitative analysis method based on the robust least squares support vector machine regression model
Authors: Yang Jianhong , Yi Cancan , Xu Jinwu , Ma Xianghong
Published: April 2015

Data fluctuation in multiple measurements of Laser Induced Breakdown Spectroscopy (LIBS) greatly affects the accuracy of quantitative analysis. Our proposed method achieved better prediction accuracy and modeling robustness.
Monolithic optofluidic ring resonator lasers created by femtosecond laser nanofabrication
Authors: Chandrahalim Hengky , Chen Qiushu , Said Ali A. , Dugan Mark , Fan Xudong
Published: April 2015

Optofluidic ring resonator laser fabricated using 3-D femto-second laser writing technology.
Universal degradation performance of a high-efficiency AgBr/Ag2CO3 photocatalyst under visible light and an insight into the reaction mechanism
Authors: Yin Lu , Wang Zhen , Lu Lian , Wan Xiankai , Shi Huixiang
Published: April 2015

A AgBr/Ag2CO3 photocatalyst exhibited excellent photocatalytic activity and stability under visible light and a two-stage photocatalytic mechanism was proposed.
Superior plasmon absorption in iron-doped gold nanoparticles
Authors: Amendola Vincenzo , Saija Rosalba , Maragò Onofrio M. , Iatì Maria Antonia
Published: April 2015

Plasmon absorption can be increased up to 200% just by doping gold nanoparticles (nanospheres, nanoshells, nanorods,etc.) with iron. The benefits of alloying Au with Fe are observed in nanostructures larger than 70–100 nm and for iron contents of 10–20 atomic%. The increment is located in the red and near infrared part of the spectrum.
Silica–gold nanoparticles for atheroprotective management of plaques: results of the NANOM-FIM trial
Authors: Kharlamov Alexander N. , Tyurnina Anastasiya E. , Veselova Vera S. , Kovtun Olga P. , Shur Vladimir Y. , Gabinsky Jan L.
Published: April 2015

Photothermal therapy with nanoparticles is associated with a mean total atheroma volume reduction of 60.3 mm3 (p < 0.05) at 12 months with a target plaque burden of 37.8% (p < 0.05) which is below Glagov threshold and promising to revolutionize interventional vascular medicine.
Low voltage and high ON/OFF ratio field-effect transistors based on CVD MoS2 and ultra high-k gate dielectric PZT
Authors: Zhou Changjian , Wang Xinsheng , Raju Salahuddin , Lin Ziyuan , Villaroman Daniel , Huang Baoling , Chan Helen Lai-Wa , Chan Mansun , Chai Yang
Published: April 2015

Ultra high-k dielectric enables low-voltage enhancement-mode MoS2 transistor with high ON/OFF ratio, leading to low-power device.
Electrospun manganese–cobalt oxide hollow nanofibres synthesized via combustion reactions and their lithium storage performance
Authors: Hwang Soo Min , Kim So Yeun , Kim Jae-Geun , Kim Ki Jae , Lee Jong-Won , Park Min-Sik , Kim Young-Jun , Shahabuddin Mohammed , Yamauchi Yusuke , Kim Jung Ho
Published: April 2015

Electrospun hollow MnCo2O4and CoMn2O4fibres were synthesized through highly exothermic oxygen-mediated combustion reactions.
Guided formation of sub-5 nm interstitial gaps between plasmonic nanodisks
Authors: Son Jin Gyeong , Han Sang Woo , Wi Jung-Sub , Lee Tae Geol
Published: April 2015

To achieve a reliable formation of a surface-enhanced Raman scattering (SERS) sensor with evenly distributed hot spots on a wafer scale substrate, we propose a hybrid approach combining physical nanolithography for preparing Au nanodisks and chemical Au reduction for growing them.
A template-free method for stable CuO hollow microspheres fabricated from a metal organic framework (HKUST-1)
Authors: Zhang Suoying , Liu Hong , Liu Pengfei , Yang Zhuhong , Feng Xin , Huo Fengwei , Lu Xiaohua
Published: April 2015

Uniform CuO hollow microspheres were successfully achieved from a non-uniform metal organic framework by spherical aggregation and Ostwald ripening.
Gradual-order enhanced stability: a frozen section of electrospun nanofibers for energy storage
Authors: Ma Xinlei , Xue Mianqi , Li Fengwang , Chen Jitao , Chen Dong , Wang Xusheng , Pan Feng , Chen G. F.
Published: April 2015

The combination of electrospinning and a frozen section has been used to fabricate homodisperse nanoparticle electrodes with high electrochemical performances.
Resveratrol-based benzoselenophenes with an enhanced antioxidant and chain breaking capacity
Authors: Tanini Damiano , Panzella Lucia , Amorati Riccardo , Capperucci Antonella , Pizzo Elio , Napolitano Alessandra , Menichetti Stefano , d'Ischia Marco
Published: April 2015

One-pot selenenylation of resveratrol with Se(0) and SO2Cl2 leads to benzoselenophene derivatives with efficient Trolox-like antioxidant and chain breaking capacity.
Synthesis of new carolacton derivatives and their activity against biofilms of oral bacteria
Authors: Stumpp N. , Premnath P. , Schmidt T. , Ammermann J. , Dräger G. , Reck M. , Jansen R. , Stiesch M. , Wagner-Döbler I. , Kirschning A.
Published: April 2015

Carolacton, a secondary metabolite isolated from the extracts ofSorangium cellulosum, causes membrane damage and cell death in biofilms of different oral bacteria.
Asymmetric Michael addition reactions of nitroalkanes to 2-furanones catalyzed by bifunctional thiourea catalysts
Authors: Bai Zhushuang , Ji Ling , Ge Zemei , Wang Xin , Li Runtao
Published: April 2015

The first bifunctional thiourea catalyzed asymmetric Michael addition reactions of nitroalkanes to 2-furanones are described.
PNIPAM-based heteroarm star-graft quarterpolymers: synthesis, characterization and pH-dependent thermoresponsiveness in aqueous media
Authors: Iatridi Zacharoula , Lencina M. M. Soledad , Tsitsilianis Constantinos
Published: April 2015

We report the design of PSn(P2VP-b-PAA-g-PNIPAM)n heteroarm star-graft quarterpolymers, the thermoresponsiveness of which is strongly dependent on pH ionic strength, and their macromolecular features, e.g. arm number and grafting density.
A mechanistic study on the SHi reaction at tin atoms in a radical cascade reaction
Authors: Kamimura Akio , Yoshinaga Tatsuro , Noguchi Fumiaki , Miyazaki Koichiro , Uno Hidemitsu
Published: April 2015

A kinetic study on the intramolecular direct radical substitution reaction on tin atoms was undertaken.
A concise formal synthesis of platencin
Authors: Wang Jie , Sun Wang-Bin , Li Ying-Zi , Wang Xuan , Sun Bing-Feng , Lin Guo-Qiang , Zou Jian-Ping
Published: April 2015

A formal synthesis of platencin features an organocatalytic approach to the [2.2.2] bicycle, a radical reductive elimination, a Au-catalyzed rearrangement and a Rh-catalyzed hydrosilylation.
In vivo evaluation of an anticancer drug delivery system based on heparinized mesoporous silica nanoparticles
Authors: Wu Qiang , Li Ruifang , Zhao Chao , Ren Jiejie , Du Keyuan , Yin Baoqing , Fu Junmin , Qiu Xiangjun , Gao Chunsheng
Published: April 2015

MSNs-HP loaded with only a low amount of a drug (DOX0.3) achieve a similar antitumor efficacy to that of large doses of the drug (DOX2.0, 7-fold higher in dosage than DOX0.3).
Spin mixed charge transfer states of iridium complex Ir(ppy)3: transient absorption and time-resolved photoluminescence
Authors: Mehata Mohan Singh , Yang Yang , Qu Zong-Jing , Chen Jun-Sheng , Zhao Feng-Jiao , Han Ke-Li
Published: April 2015

Transient absorption and time-resolved PL together with quantum chemistry calculations demonstrated the existence of multiple low-lying metal-to-ligand charge transfer states of Ir(ppy)3.
Facile synthesis of CuS mesostructures with high photothermal conversion efficiency
Authors: Tan Lianjiang , Wu Zhongyu , Wang Xiaojing , Sun Jie
Published: April 2015

CuS nanoparticles with opposite charges are assembled and calcinated to produce mesostructures with high photothermal conversion efficiency for cancer therapy.
Computational simulation of CO2removal from gas mixtures by chemical absorbents in porous membranes
Authors: Fazaeli Reza , Razavi Seyed Mohammad Reza , Sattari Najafabadi Mehdi , Torkaman Rezvan , Hemmati Alireza
Published: April 2015

In this study chemical absorption of CO2from a N2/CO2gas mixture in tetramethylammonium glycinate ([N1111][Gly]) solution using hollow-fiber membrane contactors by employing the CFD (computational fluid dynamics) method was investigated.
Genetic incorporation of d-amino acids into green fluorescent protein based on polysubstrate specificity
Authors: Ma Hairong , Liu Nan , Shi Shaobo , Wang Shuzhen , Chen Yijun
Published: April 2015

A number of d-amino acids were genetically incorporated into green fluorescent protein, and the GFPuv mutant containing d-phenylalanine in the fluorophore at residue 66 was characterized.
Binding of a quaternary ammonium polymer-grafted-chitosan onto a chemically modified wool fabric surface: assessment of mechanical, antibacterial and antifungal properties
Authors: Hassan Mohammad Mahbubul
Published: April 2015

It is quite challenging to bind any chemical compound or polymer onto a wool fibre surface because of the lack of any functional groups available on its surface.
Screening of modified CaO-based catalysts with a series of dopants for the supercritical water gasification of empty palm fruit bunches to produce hydrogen
Authors: Sivasangar S. , Mastuli M. S. , Islam A. , Taufiq-Yap Y. H.
Published: April 2015

Catalytic supercritical water gasification of empty palm fruit bunches into hydrogen rich product gases.
Incorporation of cobalt ions into magnetoelectric gallium ferrite epitaxial films: tuning of conductivity and magnetization
Authors: Oh S. H. , Shin R. H. , Lefèvre C. , Thomasson A. , Roulland F. , Shin Y. , Kim D.-H. , Kim J.-Y. , Demchenko A. , Leuvrey C. , Mény C. , Jo W. , Viart N.
Published: April 2015

Doping Ga0.6Fe1.4O3 thin films with magnetic Co2+ ions leads to a strong reduction in the charge conduction and does not lead to any modification of the ferrimagnetic transition. This is absolutely comparable to that observed with Mg-doping.
Routes towards catalytically active TiO2doped porous cellulose
Authors: Wittmar Alexandra , Thierfeld Hanna , Köcher Steffen , Ulbricht Mathias
Published: April 2015

Cellulose–TiO2membranes with photocatalytic activity were prepared by non-solvent induced phase separation from cellulose solutions in ionic liquids or from cellulose acetate solutions in organic solvents followed by deacetylation.
Cuprous oxide microspheres on graphene nanosheets: an enhanced material for non-enzymatic electrochemical detection of H2O2 and glucose
Authors: Ding Junwei , Sun Wei , Wei Gang , Su Zhiqiang
Published: April 2015

Reduced graphene oxide nanosheets decorated with cuprous oxide microspheres show improved performances as a novel electrochemical sensor material.
Coordination-driven self-assembly: construction of a Fe3O4–graphene hybrid 3D framework and its long cycle lifetime for lithium-ion batteries
Authors: Ren Zhimin , Yu Siqi , Fu Xinxin , Shi Lin , Sun Chunxiao , Fan Chenyao , Liu Qi , Qian Guodong , Wang Zhiyu
Published: April 2015

A three-dimensional graphene framework with uniform distribution of hierarchical Fe3O4 spheres was prepared via a one-pot solvothermal method.
Experimental and theoretical evaluation of trans-3-halo-2-hydroxy-tetrahydropyran conformational preferences. Beyond anomeric interaction
Authors: Barbosa Thaís M. , Viesser Renan V. , Abraham Raymond J. , Rittner Roberto , Tormena Cláudio F.
Published: April 2015

Which analysis will explain the preferences of the substituents in the hydro-halo-tetrahydropyran rings? Is the anomeric effect essential to understand what is going on?
A simple growth method for Nb2O5 films and their optical properties
Authors: Dash J. K. , Chen L. , Topka Michael R. , Dinolfo Peter H. , Zhang L. H. , Kisslinger K. , Lu T.-M. , Wang G.-C.
Published: April 2015

Synthesis of Nb2O5 thin films from sputter deposited Nb films and its optical property.
Synthesis of benzofused 1,4-azaborinols via [4 + 2] annulation strategy and its application in indole synthesis
Authors: Chinnapattu Murugan , Sathiyanarayanan Kulathu Iyer , Iyer Pravin S.
Published: April 2015

The first general synthesis of benzofused 1,4-azaborinols via [4 + 2] annulation strategy and its application in indole synthesis.
Cobalt(ii) complexes with the quinolone antimicrobial drug oxolinic acid: structure and biological perspectives
Authors: Irgi Evgenia P. , Geromichalos George D. , Balala Sofia , Kljun Jakob , Kalogiannis Stavros , Papadopoulos Athanasios , Turel Iztok , Psomas George
Published: April 2015

The interaction of cobalt(ii)–oxolinato complexes with DNA and albumins was investigated with spectroscopic and physicochemical techniques and molecular docking calculations.
N-heterocyclic carbene-catalysed pentafluorophenylation of aldehydes
Authors: Du Guang-Fen , Xing Fen , Gu Cheng-Zhi , Dai Bin , He Lin
Published: April 2015

N-heterocyclic carbenes have been utilized as highly efficient organocatalysts to catalyse multifluorophenylation of aldehydes with fluorinated aryltrimethylsilanes to afford the corresponding adducts in 49–99% yields.
Enhanced electrochemical capabilities of lithium ion batteries by structurally ideal AAO separator
Authors: Ahn Yong-keon , Park Junwoo , Shin Dalwoo , Cho Sanghun , Park Si Yun , Kim Hyunjin , Piao Yuanzhe , Yoo Jeeyoung , Kim Youn Sang
Published: April 2015

Nanoporous anodic aluminium oxide (AAO) enables the direct utilization of lithium metal as an ideal anode, owing to a uniform current distribution. The electrochemical performance of the AAO separator is superior to commercial polypropylene, in terms of ionic conductivity, discharge capacity, and capacity fading.
Low-absorption, multi-layered scintillating material for high resolution real-time X-ray beam analysis
Authors: Pereira Antonio , Martin Thierry , Levinta Mariana , Dujardin Christophe
Published: April 2015

A novel multi-layered screen for X-ray beam analysis at high speed with a high imaging resolution capability. The route toward real-time beam corrections for synchrotron experiments is presented.
Single beam test (SBT) as a criterion for the resolution of holographic recording
Authors: Sobolewska Anna , Bartkiewicz Stanislaw
Published: April 2015

Formation of the willow structure resulting from irradiation of a single laser beam limits the resolution of holographic recording.
Reversible bonding by dimethyl‐methylphenylmethoxy siloxane – based stamping technique for reusable poly(dimethylsiloxane) microfluidic chip
Authors: Cao Hong Ha , Dinh Thi Hong Nhung , Hamdi Feriel S. , Couty Magdalèna , Martincic Emile , Woytasik Marion , Dufour‐Gergam Elisabeth
Published: April 2015

Reversible packaging is very desirable for microfluidic chips: it allows changing the chip upper cap when it is damaged, cleaning and reusing the chip bottom substrate. This latter case becomes even more attractive when integrated components are present on the substrate and have required a complex and expensive microfabrication process. The feasibility of poly(dimethylsiloxane) (PDMS)/PDMS and PDMS/glass reversible bonding is demonstrated using the stamping technique. Dimethyl‐methylphenylmethoxy siloxane (DMPMS), a type of silicone conformal coating, is used as an adhesive layer between the PDMS channel and the substrate (PDMS or glass). This technique is easy to perform as it only needs spin‐coating and thermal curing steps. The bond strength is suitable for high working flow rate/pressure of liquid in the channel (up to 500 μl/min and 200 kPa). The cycle ‘pealing/bonding’ of the cap can be repeated up to five times. In addition, an MTT cell proliferation assay has been performed and suggests the non‐cytotoxicity of DMPMS. Thus, the DMPMS‐stamping bonding technique opens new perspectives for PDMS biochips where plasma treatment is not possible such as functionalised surfaces.
Self-organisation and non-linear dynamics in driven magnetohydrodynamic turbulent flows
Authors: Dallas V. , Alexakis A.
Published: April 2015

Magnetohydrodynamic (MHD) turbulent flows driven by random, large-scale, mechanical and electromagnetic external forces of zero helicities are investigated by means of direct numerical simulations. It is shown that despite the absence of helicities in the forcing, the system is attracted to helical states of large scale condensates that exhibit laminar behaviour despite the large value of the Reynolds numbers examined. We demonstrate that the correlation time of the external forces controls the time spent on these states, i.e., for short correlation times, the system remains in the turbulent state while as the correlation time is increased, the system spends more and more time in the helical states. As a result, time averaged statistics are significantly affected by the time spent on these states. These results have important implications for MHD and turbulence theory and they provide insight into various physical phenomena where condensates transpire.
Preformed template fluctuations promote fibril formation: Insights from lattice and all-atom models
Authors: Kouza Maksim , Co Nguyen Truong , Nguyen Phuong H. , Kolinski Andrzej , Li Mai Suan
Published: April 2015

Fibril formation resulting from protein misfolding and aggregation is a hallmark of several neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases. Despite the fact that the fibril formation process is very slow and thus poses a significant challenge for theoretical and experimental studies, a number of alternative pictures of molecular mechanisms of amyloid fibril formation have been recently proposed. What seems to be common for the majority of the proposed models is that fibril elongation involves the formation of pre-nucleus seeds prior to the creation of a critical nucleus. Once the size of the pre-nucleus seed reaches the critical nucleus size, its thermal fluctuations are expected to be small and the resulting nucleus provides a template for sequential (one-by-one) accommodation of added monomers. The effect of template fluctuations on fibril formation rates has not been explored either experimentally or theoretically so far. In this paper, we make the first attempt at solving this problem by two sets of simulations. To mimic small template fluctuations, in one set, monomers of the preformed template are kept fixed, while in the other set they are allowed to fluctuate. The kinetics of addition of a new peptide onto the template is explored using all-atom simulations with explicit water and the GROMOS96 43a1 force field and simple lattice models. Our result demonstrates that preformed template fluctuations can modulate protein aggregation rates and pathways. The association of a nascent monomer with the template obeys the kinetics partitioning mechanism where the intermediate state occurs in a fraction of routes to the protofibril. It was shown that template immobility greatly increases the time of incorporating a new peptide into the preformed template compared to the fluctuating template case. This observation has also been confirmed by simulation using lattice models and may be invoked to understand the role of template fluctuations in slowing down fibril elongation in vivo.
Weakly relativistic plasma expansion
Authors: Fermous Rachid , Djebli Mourad
Published: April 2015

Plasma expansion is an important physical process that takes place in laser interactions with solid targets. Within a self-similar model for the hydrodynamical multi-fluid equations, we investigated the expansion of both dense and under-dense plasmas. The weakly relativistic electrons are produced by ultra-intense laser pulses, while ions are supposed to be in a non-relativistic regime. Numerical investigations have shown that relativistic effects are important for under-dense plasma and are characterized by a finite ion front velocity. Dense plasma expansion is found to be governed mainly by quantum contributions in the fluid equations that originate from the degenerate pressure in addition to the nonlinear contributions from exchange and correlation potentials. The quantum degeneracy parameter profile provides clues to set the limit between under-dense and dense relativistic plasma expansions at a given density and temperature.
Waveguide-integrated single- and multi-photon detection at telecom wavelengths using superconducting nanowires
Authors: Ferrari Simone , Kahl Oliver , Kovalyuk Vadim , Goltsman Gregory N. , Korneev Alexander , Pernice Wolfram H. P.
Published: April 2015

We investigate single- and multi-photon detection regimes of superconducting nanowire detectors embedded in silicon nitride nanophotonic circuits. At near-infrared wavelengths, simultaneous detection of up to three photons is observed for 120 nm wide nanowires biased far from the critical current, while narrow nanowires below 100 nm provide efficient single photon detection. A theoretical model is proposed to determine the different detection regimes and to calculate the corresponding internal quantum efficiency. The predicted saturation of the internal quantum efficiency in the single photon regime agrees well with plateau behavior observed at high bias currents.
Impact of yttria stabilized zirconia nanoinclusions on the thermal conductivity of n-type Si80Ge20 alloys prepared by spark plasma sintering
Authors: Lahwal Ali , Bhattacharya S. , He Jian , Wu Di , Peterson A. , Poon S. J. , Williams L. , Dehkordi A. Mehdizadeh , Tritt T. M.
Published: April 2015

Nanocomposites have become a new paradigm for thermoelectric research in recent years and have resulted in the reduction of thermal conductivity via the nano-inclusion and grain boundary scattering. In this work, we report the preparation and thermoelectric study of SiGe-yttria stabilized zirconia (YSZ) nanocomposites prepared by Spark Plasma Sintering (SPS). We experimentally investigated the reduction of lattice thermal conductivity (κL) in the temperature range (30–800 K) of n-type Si80Ge20P2 alloys with the incorporation of YSZ nanoparticles (20–40 nm diameter) into the Si-Ge matrix. These samples synthesized by using the SPS technique were found to have densities > 95% of the theoretical density. The thermal conductivity, at both low and high temperatures, was measured by steady state and laser flash techniques, respectively. At room temperature, we observed approximately a 50% reduction in the lattice thermal conductivity as result of adding 10% YSZ by volume to the Si80Ge20P2 host matrix. A phenomenological model developed by Callaway was used to corroborate both the temperature dependence and reduction of κL over the measured temperature range (30–800 K) of both Si80Ge20P2 and Si80Ge20P2 + YSZ samples. The observed κL is discussed and interpreted in terms of various phonon scattering mechanisms such as alloy disorder, the Umklapp phonon scattering, and boundary scattering. In addition, a contribution from the phonon scattering by YSZ nanoparticles was further included to account for the κL of Si80Ge20P2 + YSZ sample. The theoretical calculations are in reasonably good agreement with the experimental results for both the Si80Ge20P2 and Si80Ge20P2 + YSZ alloys.
Nonlinear study of an ion-channel guiding free-electron laser
Authors: Ouyang Zhengbiao , Zhang Shi-Chang
Published: April 2015

A nonlinear model and simulations of the output power of an ion-channel guiding free-electron laser (FEL) are presented in this paper. Results show that the nonlinear output power of an ion-channel guiding FEL is comparable to that of an axial guide magnetic field FEL. Compared to an axial guide magnetic field FEL, an ion-channel guiding FEL substantially weakens the negative effect of the electron-beam energy spread on the output power due to its advantageous focusing mechanism on the electron motion.
A compact broadband ion beam focusing device based on laser-driven megagauss thermoelectric magnetic fields
Authors: Albertazzi B. , d’Humières E. , Lancia L. , Dervieux V. , Antici P. , Böcker J. , Bonlie J. , Breil J. , Cauble B. , Chen S. N. , Feugeas J. L. , Nakatsutsumi M. , Nicolaï P. , Romagnani L. , Shepherd R. , Sentoku Y. , Swantusch M. , Tikhonchuk V. T. , Borghesi M. , Willi O. , Pépin H. , Fuchs J.
Published: April 2015

Ultra-intense lasers can nowadays routinely accelerate kiloampere ion beams. These unique sources of particle beams could impact many societal (e.g., proton-therapy or fuel recycling) and fundamental (e.g., neutron probing) domains. However, this requires overcoming the beam angular divergence at the source. This has been attempted, either with large-scale conventional setups or with compact plasma techniques that however have the restriction of short (<1 mm) focusing distances or a chromatic behavior. Here, we show that exploiting laser-triggered, long-lasting (>50 ps), thermoelectric multi-megagauss surface magnetic (B)-fields, compact capturing, and focusing of a diverging laser-driven multi-MeV ion beam can be achieved over a wide range of ion energies in the limit of a 5° acceptance angle.
Using atomic layer deposited tungsten to increase thermal conductivity of a packed bed
Authors: Van Norman Staci A. , Tringe Joseph W. , Sain John D. , Yang Ronggui , Falconer John L. , Weimer Alan W.
Published: April 2015

This study investigated the effective thermal conductivity (keff) of packed-beds that contained porous particles with nanoscale tungsten (W) films of different thicknesses formed by atomic layer deposition (ALD). A continuous film on the particles is vital towards increasing keff of the packed beds. For example, the keff of an alumina packed bed was increased by three times after an ∼8-nm continuous W film with 20 cycles of W ALD, whereas keff was decreased on a polymer packed bed with discontinuous, evenly dispersed W-islands due to nanoparticle scattering of phonons. For catalysts, understanding the thermal properties of these packed beds is essential for developing thermally conductive supports as alternatives to structured supports.
Lineshape analysis of coherent multidimensional optical spectroscopy using incoherent light
Authors: Ulness Darin J. , Turner Daniel B.
Published: April 2015

Coherent two-dimensional electronic spectroscopy using incoherent (noisy) light, I(4) 2D ES, holds intriguing challenges and opportunities. One challenge is to determine how I(4) 2D ES compares to femtosecond 2D ES. Here, we merge the sophisticated energy-gap Hamiltonian formalism that is often used to model femtosecond 2D ES with the factorized time-correlation formalism that is needed to describe I(4) 2D ES. The analysis reveals that in certain cases the energy-gap Hamiltonian is insufficient to model the spectroscopic technique correctly. The results using a modified energy-gap Hamiltonian show that I(4) 2D ES can reveal detailed lineshape information, but, contrary to prior reports, does not reveal dynamics during the waiting time.
Measurements of the energy spectrum of electrons emanating from solid materials irradiated by a picosecond laser
Authors: Di Stefano C. A. , Kuranz C. C. , Seely J. F. , Thomas A. G. R. , Drake R. P. , Keiter P. A. , Williams G. J. , Park J. , Chen H. , MacDonald M. J. , Rasmus A. M. , Wan W. C. , Pereira N. R. , Joglekar A. S. , McKelvey A. , Zhao Z. , Klein S. R. , Kemp G. E. , Jarrott L. C. , Krauland C. M. , Peebles J. , Westover B.
Published: April 2015

In this work, we present the results of experiments observing the properties of the electron stream generated laterally when a laser irradiates a metal. We find that the directionality of the electrons is dependent upon their energies, with the higher-energy tail of the spectrum (∼1 MeV and higher) being more narrowly focused. This behavior is likely due to the coupling of the electrons to the electric field of the laser. The experiments are performed by using the Titan laser to irradiate a metal wire, creating the electron stream of interest. These electrons propagate to nearby spectator wires of differing metals, causing them to fluoresce at their characteristic K-shell energies. This fluorescence is recorded by a crystal spectrometer. By varying the distances between the wires, we are able to probe the divergence of the electron stream, while by varying the medium through which the electrons propagate (and hence the energy-dependence of electron attenuation), we are able to probe the energy spectrum of the stream.
Instability saturation by the oscillating two-stream instability in a weakly relativistic plasma
Authors: Pal Barnali , Poria Swarup , Sahu Biswajit
Published: April 2015

The two-stream instability has wide range of astrophysical applications starting from gamma-ray bursts and pulsar glitches to cosmology. We consider one dimensional weakly relativistic Zakharov equations and describe nonlinear saturation of the oscillating two-stream instability using a three dimensional dynamical system resulting form a truncation of the nonlinear Schrodinger equation to three modes. The equilibrium points of the model are determined and their stability natures are discussed. Using the tools of nonlinear dynamics such as the bifurcation diagram, Poincaré maps, and Lyapunav exponents, existence of periodic, quasi-periodic, and chaotic solutions are established in the dynamical system. Interestingly, we observe the multistable behavior in this plasma model. The system has multiple attractors depending on the initial conditions. We also notice that the relativistic parameter plays the role of control parameter in the model. The theoretical results presented in this paper may be helpful for better understanding of space and astrophysical plasmas.
Consistent multi-internal-temperature models for vibrational and electronic nonequilibrium in hypersonic nitrogen plasma flows
Authors: Guy Aurélien , Bourdon Anne , Perrin Marie-Yvonne
Published: April 2015

In this work, a state-to-state vibrational and electronic collisional model is developed to investigate nonequilibrium phenomena behind a shock wave in an ionized nitrogen flow. In the ionization dynamics behind the shock wave, the electron energy budget is of key importance and it is found that the main depletion term corresponds to the electronic excitation of N atoms, and conversely the major creation terms are the electron-vibration term at the beginning, then replaced by the electron ions elastic exchange term. Based on these results, a macroscopic multi-internal-temperature model for the vibration of N2 and the electronic levels of N atoms is derived with several groups of vibrational levels of N2 and electronic levels of N with their own internal temperatures to model the shape of the vibrational distribution of N2 and of the electronic excitation of N, respectively. In this model, energy and chemistry source terms are calculated self-consistently from the rate coefficients of the state-to-state database. For the shock wave condition studied, a good agreement is observed on the ionization dynamics as well as on the atomic bound-bound radiation between the state-to-state model and the macroscopic multi-internal temperature model with only one group of vibrational levels of N2 and two groups of electronic levels of N.
Theoretical investigation of resonant frequencies of unstrapped magnetron with arbitrary side resonators
Authors: Yue Song , Zhang Zhao-chuan , Gao Dong-ping
Published: April 2015

In this paper, a sector steps approximation method is proposed to investigate the resonant frequencies of magnetrons with arbitrary side resonators. The arbitrary side resonator is substituted with a series of sector steps, in which the spatial harmonics of electromagnetic field are also considered. By using the method of admittance matching between adjacent steps, as well as field continuity conditions between side resonators and interaction regions, the dispersion equation of magnetron with arbitrary side resonators is derived. Resonant frequencies of magnetrons with five common kinds of side resonators are calculated with sector steps approximation method and computer simulation softwares, in which the results have a good agreement. The relative error is less than 2%, which verifies the validity of sector steps approximation method.
Note: Establishing α-particle radiation damage experiments using the Dalton Cumbrian Facility’s 5 MV tandem pelletron
Authors: Bower W. R. , Smith A. D. , Pattrick R. A. D. , Pimblott S. M.
Published: April 2015

Evaluating the radiation stability of mineral phases is a vital research challenge when assessing the performance of the materials employed in a Geological Disposal Facility for radioactive waste. This report outlines the setup and methodology for efficiently allowing the determination of the dose dependence of damage to a mineral from a single ion irradiated sample. The technique has been deployed using the Dalton Cumbrian Facility’s 5 MV tandem pelletron to irradiate a suite of minerals with a controlled α-particle (4He2+) beam. Such minerals are proxies for near-field clay based buffer material surrounding radioactive canisters, as well as the sorbent components of the host rock.
Graphene photodetector integrated on silicon nitride waveguide
Authors: Wang Jiaqi , Cheng Zhenzhou , Chen Zefeng , Xu Jian-Bin , Tsang Hon Ki , Shu Chester
Published: April 2015

We demonstrated a graphene photodetector integrated on silicon nitride waveguide. The photodetector worked in the photoconductor mode. The detection mechanisms of the device were based on photo-thermoelectric effect and bolometric effect. The waveguide absorption (0.025 dB/μm) with a chemical vapor deposition grown monolayer graphene on top was studied experimentally. The measurement agreed well with the simulation result. The Fermi level of the top layer graphene in the photodetector was analyzed by using the field-effect transport measurement. A maximum internal responsivity of 126 mA/W with dynamic response of 1 K Hz was achieved in the telecommunication band. The unique combination of graphene and silicon nitride integrated circuit can potentially lead to unprecedented nonlinear and optoelectronic applications.
Photoluminescence quantum yield of PbS nanocrystals in colloidal suspensions
Authors: Greben M. , Fucikova A. , Valenta J.
Published: April 2015

The absolute photoluminescence (PL) quantum yield (QY) of oleic acid-capped colloidal PbS quantum dots (QDs) in toluene is thoroughly investigated as function of QD size, concentration, excitation photon energy, and conditions of storage. We observed anomalous decrease of QY with decreasing concentration for highly diluted suspensions. The ligand desorption and QD-oxidation are demonstrated to be responsible for this phenomenon. Excess of oleic acid in suspensions makes the QY values concentration-independent over the entire reabsorption-free range. The PL emission is shown to be dominated by surface-related recombinations with some contribution from QD-core transitions. We demonstrate that QD colloidal suspension stability improves with increasing the concentration and size of PbS QDs.
Microstructure and magnetic properties of MFe2O4 (M = Co, Ni, and Mn) ferrite nanocrystals prepared using colloid mill and hydrothermal method
Authors: Wang Wei , Ding Zui , Zhao Xiruo , Wu Sizhu , Li Feng , Yue Ming , Liu J. Ping
Published: April 2015

Three kinds of spinel ferrite nanocrystals, MFe2O4 (M = Co, Ni, and Mn), are synthesized using colloid mill and hydrothermal method. During the synthesis process, a rapid mixing and reduction of cations with sodium borohydride (NaBH4) take place in a colloid mill then through a hydrothermal reaction, a slow oxidation and structural transformation of the spinel ferrite nanocrystals occur. The phase purity and crystal lattice parameters are estimated by X-ray diffraction studies. Scanning electron microscopy and transmission electron microscopy images show the morphology and particle size of the as-synthesized ferrite nanocrystals. Raman spectrum reveals active phonon modes at room temperature, and a shifting of the modes implies cation redistribution in the tetrahedral and octahedral sites. Magnetic measurements show that all the obtained samples exhibit higher saturation magnetization (Ms). Meanwhile, experiments demonstrate that the hydrothermal reaction time has significant effects on microstructure, morphologies, and magnetic properties of the as-synthesized ferrite nanocrystals.
Low temperature growth of Co2MnSi films on diamond semiconductors by ion-beam assisted sputtering
Authors: Nishiwaki M. , Ueda K. , Asano H.
Published: April 2015

High quality Schottky junctions using Co2MnSi/diamond heterostructures were fabricated. Low temperature growth at ∼300–400 °C by using ion-beam assisted sputtering (IBAS) was necessary to obtain abrupt Co2MnSi/diamond interfaces. Only the Co2MnSi films formed at ∼300–400 °C showed both saturation magnetization comparable to the bulk values and large negative anisotropic magnetoresistance, which suggests half-metallic nature of the Co2MnSi films, of ∼0.3% at 10 K. Schottky junctions formed using the Co2MnSi films showed clear rectification properties with rectification ratio of more than 107 with Schottky barrier heights of ∼0.8 eV and ideality factors (n) of ∼1.2. These results indicate that Co2MnSi films formed at ∼300–400 °C by IBAS are a promising spin source for spin injection into diamond semiconductors.
Influence of shear on globule formation in dilute solutions of flexible polymers
Authors: Radhakrishnan Rangarajan , Underhill Patrick T.
Published: April 2015

Polyelectrolytes, polymers in poor solvents, polymers mixed with particles, and other systems with attractions and repulsions show formation of globules/structures in equilibrium or in flow. To study the flow behavior of such systems, we developed a simple coarse-grained model with short ranged attractions and repulsions. Polymers are represented as charged bead-spring chains and they interact with oppositely charged colloids. Neglecting hydrodynamic interactions, we study the formation of compact polymer structures called globules. Under certain conditions, increase in shear rate decreases the mean first passage time to form a globule. At other conditions, shear flow causes the globules to breakup, similar to the globule-stretch transition of polymers in poor solvents.
Effects of interlayer growth condition on the transport properties of heterostructures with InGaN channel grown on sapphire by metal organic chemical vapor deposition
Authors: Zhang Yachao , Zhou Xiaowei , Xu Shengrui , Wang Zhizhe , Zhao Yi , Zhang Jinfeng , Chen Dazheng , Zhang Jincheng , Hao Yue
Published: April 2015

The effects of AlN interlayer growth condition on the properties of InAlN/InGaN heterostructures are investigated in detail. Since the properties of InGaN channel are different from the traditional GaN channel, two-step AlN interlayer is proposed, which is proven to be more suitable for the InGaN channel heterostructures than the interlayers grown at constant temperature. Test results show that two-step AlN interlayer can not only significantly improve the interface morphology between the InGaN channel and barrier layers but also make an effective protection of the high-quality InGaN channel. The electron mobility of the InAlN/InGaN heterostructure with two-step AlN interlayer achieves 890 cm2/V s with a high two-dimensional-electron-gas density of 1.78 × 1013 cm−2. The gratifying results indicate that the InGaN channel heterostructure with two-step interlayer is a promising candidate for microwave power devices.
Significant mobility enhancement in extremely thin highly doped ZnO films
Authors: Look David C. , Heller Eric R. , Yao Yu-Feng , Yang C. C.
Published: April 2015

Highly Ga-doped ZnO (GZO) films of thicknesses d = 5, 25, 50, and 300 nm, grown on 160-nm ZnO buffer layers by molecular beam epitaxy, had 294-K Hall-effect mobilities μH of 64.1, 43.4, 37.0, and 34.2 cm2/V-s, respectively. This extremely unusual ordering of μH vs d is explained by the existence of a very high-mobility Debye tail in the ZnO, arising from the large Fermi-level mismatch between the GZO and the ZnO. Scattering theory in conjunction with Poisson analysis predicts a Debye-tail mobility of 206 cm2/V-s at the interface (z = d), falling to 58 cm2/V-s at z = d + 2 nm. Excellent fits to μH vs d and sheet concentration ns vs d are obtained with no adjustable parameters.
Rapid bench-top fabrication of poly(dimethylsiloxane)/polystyrene microfluidic devices incorporating high-surface-area sensing electrodes
Authors: Sonney Sanjay , Shek Norman , Moran-Mirabal Jose M.
Published: April 2015

The development of widely applicable point-of-care sensing and diagnostic devices can benefit from simple and inexpensive fabrication techniques that expedite the design, testing, and implementation of lab-on-a-chip devices. In particular, electrodes integrated within microfluidic devices enable the use of electrochemical techniques for the label-free detection of relevant analytes. This work presents a novel, simple, and cost-effective bench-top approach for the integration of high surface area three-dimensional structured electrodes fabricated on polystyrene (PS) within poly(dimethylsiloxane) (PDMS)-based microfluidics. Optimization of PS-PDMS bonding results in integrated devices that perform well under pressure and fluidic flow stress. Furthermore, the fabrication and bonding processes are shown to have no effect on sensing electrode performance. Finally, the on-chip sensing capabilities of a three-electrode electrochemical cell are demonstrated with a model redox compound, where the high surface area structured electrodes exhibit ultra-high sensitivity. We propose that the developed approach can significantly expedite and reduce the cost of fabrication of sensing devices where arrays of functionalized electrodes can be used for point-of-care analysis and diagnostics.
Interaction of nickel and manganese in uptake, translocation and accumulation by the nickel-hyperaccumulator plant, Alyssum bracteatum (Brassicaceae)
Authors: Ghaderian S. Majid , Ghasemi Rasoul , Hajihashemi Faeze
Published: April 2015

Serpentine soils are often characterised by high concentrations of heavy metals, high plant diversity and endemism, and, in some cases, the presence of plants that hyperaccumulate nickel (Ni). Nickel uptake by hyperaccumulator plants could potentially be affected by other heavy metals in serpentine soils, such as manganese (Mn), which competes for uptake at roots. The present study investigated interactions between Ni and Mn in metal uptake, translocation and storage in a serpentine-endemic Ni-hyperaccumulator plant, Alyssum bracteatum (Brassicaceae), native to western Iran. The results based on a factorial treatment of seedlings using Ni and Mn and elemental analyses showed that whole shoot and root Ni concentrations were inversely correlated with Mn in the growing medium. Likewise, whole shoot and root Mn concentrations were inversely correlated with Ni in the medium, suggesting competition between Ni and Mn for uptake at roots. No evidence was found for competition between Ni and Mn for translocation between the roots and shoot.
From image processing to computer vision: plant imaging grows up
Authors: Dee Hannah , French Andrew
Published: April 2015

Image analysis is a field of research which, combined with novel methods of capturing images, can help to bridge the genotype–phenotype gap, where our understanding of the genotype has until now been leaps and bounds ahead of our ability to work with the phenotype. Methods of automating image capture in plant science research have increased in usage recently, as has the need to provide objective and highly accurate measures on large image datasets, thereby bringing the phenotype back to the centre of interest. In this special issue of Functional Plant Biology, we present some recent advances in the field of image analysis, and look at examples of different kinds of image processing and computer vision, which is occurring with increasing frequency in the plant sciences.