Novel graphene/Sn and graphene/SnO_x hybrid nanostructures: Induced superconductivity and band gaps revealed by scanning probe measurements

Pá,linká,s, Andrá,s,Molná,r, Gyö,rgy,Magda, Gá,bor Zsolt,Hwang, Chanyong,Tapaszt&oacute,, Levente,Samuely, Peter,Szab&oacute,, Pavol,Osvá,th, Zoltá,n Elsevier 2017 Carbon Vol.124 No.-

<P>The development of functional composite nanomaterials based on graphene and metal nanoparticles (NPs) is currently the subject of intense research interest. In this study we report the preparation of novel type of graphene/Sn and graphene/SnOx (1 <= x <= 2) hybrid nanostructures and their investigation by scanning probe methods. First, we prepare Sn NPs by evaporating 7-8 nm tin on highly oriented pyrolytic graphite substrates. Graphene/Sn nanostructures are obtained by transferring graphene on top of the tin NPs immediately after evaporation. We show by scanning tunnelling microscopy (STM) and spectroscopy (STS) that tin NPs reduce significantly the environmental p-type doping of graphene. Furthermore, we demonstrate by low-temperature STM and STS measurements that superconductivity is induced in graphene, either directly supported by Sn NPs or suspended between them. Additionally, we prepare SnOx NPs by annealing the evaporated tin at 500 degrees C. STS measurements performed on hybrid graphene/SnOx nanostructures reveal the electronic band gap of SnOx NPs. The results can open new avenues for the fabrication of novel hybrid superconducting nanomaterials with designed structures and morphologies. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Evaluation of a membrane permeation system for biogas upgrading using model and real gaseous mixtures: The effect of operating conditions on separation behaviour, methane recovery and process stability

Nemest&oacute,thy, Ná,ndor,Bakonyi, Pé,ter,Szentgyö,rgyi, Eszter,Kumar, Gopalakrishnan,Nguyen, Dinh Duc,Chang, Soon Woong,Kim, Sang-Hyoun,Bé,lafi-Bak&oacute,, Katalin Elsevier 2018 JOURNAL OF CLEANER PRODUCTION Vol.185 No.-

<P><B>Abstract</B></P> <P>In this paper, the enrichment of methane by membrane technology was studied by employing (i) a model as well as (ii) a real biogas mixture produced on a laboratory-scale. Thereafter, the endurance of the process was tested at an existing biogas plant. The commercial gas separation module under investigation contained hollow fiber membranes with a polyimide selective layer. During the measurements, the effect of critical factors (including the permeate-to-feed pressure ratio and the splitting factor) was sought in terms of the (i) CH<SUB>4</SUB> content on the retentate-side and (ii) CH<SUB>4</SUB> recovery, which are important measures of biogas upgrading efficiency. The results indicated that a retentate with 93.8 vol% of CH<SUB>4</SUB> – almost biomethane (>95 vol% of CH<SUB>4</SUB>) quality – could be obtained using the model gas (consisting of 80 vol% of CH<SUB>4</SUB> and 20 vol% of CO<SUB>2</SUB>) along with 77.4% CH<SUB>4</SUB> recovery in the single-stage permeation system. However, in the case of the real biogas mixture, ascribed primarily to inappropriate N<SUB>2</SUB>/CH<SUB>4</SUB> separation, the peak methane concentration noted was only 80.7 vol% with a corresponding 76% CH<SUB>4</SUB> recovery. Besides, longer-term experiments revealed the adequate time-stability of membrane purification, suggesting such a process is feasible under industrial conditions for the improvement of biogas quality.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Membrane gas separation was applied for biogas enrichment. </LI> <LI> Polyimide membrane was investigated to deliver biomethane. </LI> <LI> Significant variables affecting membrane performance were evaluated. </LI> <LI> Process efficiency was dependent on gas composition (model vs. real biogas). </LI> <LI> The gas permeation was steady in longer-terms using real biogas mixture. </LI> </UL> </P>

Assessment via the modified gompertz-model reveals new insights concerning the effects of ionic liquids on biohydrogen production

Nemest&oacute,thy, Ná,ndor,Bakonyi, Pé,ter,R&oacute,zsenberszki, Tamá,s,Kumar, Gopalakrishnan,Ko&oacute,k, Lá,szl&oacute,Kelemen, Gá,bor,Kim, Sang-Hyoun,Bé,lafi-Bak Elsevier 2018 International journal of hydrogen energy Vol.43 No.41

<P><B>Abstract</B></P> <P>Lignocellulosic biofuel, in particular hydrogen gas production is governed by successful feedstock pretreatment, hydrolysis and fermentation. In these days, remarkable attention is paid to the use of ionic liquids to make the fermentable regions of lignocellulose biomass more accessible to the biocatalysts. Although these compounds have great potential for this purpose, their presence during the consecutive fermentation stage may pose a threat on process stability due to certain toxic effects. This, however, has not been specifically elaborated for dark fermentative biohydrogen generation. Hence, in this work, two common imidazolium-type ionic liquids (1-butyl-3-methylimidazolium acetate, ([bmim][Ac]) and 1-butyl-3-methylimidazolium chloride, ([bmim][Cl])) were employed in mixed culture biohydrogen fermentation to investigate the possible impacts related to their presence and concentrations. The batch assays were evaluated comparatively via the modified Gompertz-model based on the important parameters characterizing the process, namely the biohydrogen production potential, maximum biohydrogen production rate and lag-phase time.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The impact of imidazolium-type ionic liquids on biohydrogen formation was tested. </LI> <LI> The batch biohydrogen production process was evaluated kinetically. </LI> <LI> Both [bmim][Ac] and [bmim][Cl] affected the biohydrogen formation performance. </LI> <LI> The anion part of ionic liquids ([Ac]<SUP>-</SUP> vs. [Cl]<SUP>-</SUP>) demonstrated notable effect. </LI> </UL> </P>

OGLE-2013-BLG-0132Lb and OGLE-2013-BLG-1721Lb: Two Saturn-mass Planets Discovered around M-dwarfs

Mr&oacute,z, Przemek,Udalski, A.,Bond, I. A.,Skowron, J.,Sumi, T.,Han, C.,Szymań,ski, M. K.,Soszyń,ski, I.,Poleski, R.,Pietrukowicz, P.,Kozłowski, S.,Wyrzykowski, Ł.,Ulaczyk, K.,Abe, F.,Asak American Astronomical Society 2017 The Astronomical journal Vol.154 No.5

<P>We present the discovery of two planetary systems consisting of a Saturn-mass planet orbiting an M-dwarf, which were detected in faint microlensing events OGLE-2013-BLG-0132 and OGLE-2013-BLG-1721. The planetary anomalies were covered with high cadence by Optical Gravitational Lensing Experiment (OGLE) and Microlensing Observations in Astrophysics (MOA) photometric surveys. The light curve modeling indicates that the planet-to-host mass ratios are (5.15 +/- 0.28) x 10(-4) and (13.18 +/- 0.72) x 10(-4), respectively. Both events were too short and too faint to measure a reliable parallax signal and hence the lens mass. We therefore used a Bayesian analysis to estimate the masses of both planets: 0.29(-0.13) (+0.16) M-Jup (OGLE-2013-BLG-0132Lb) and 0.64(-0.31)(+0.35) M-Jup (OGLE-2013-BLG-1721Lb). Thanks to a high relative proper motion, OGLE-2013-BLG-0132 is a promising candidate for the high-resolution imaging follow-up. Both planets belong to an increasing sample of sub-Jupiter-mass planets orbiting M-dwarfs beyond the snow line.</P>

Hysteretic Faraday waves

Pé,rinet, Nicolas,Falc&oacute,n, Claudio,Chergui, Jalel,Juric, Damir,Shin, Seungwon American Physical Society 2016 Physical Review E Vol.93 No.6

Evolution of asexual and sexual reproduction in the aspergilli

Ojeda-L&oacute,pez, M.,Chen, W.,Eagle, C.E.,Gutié,rrez, G.,Jia, W.L.,Swilaiman, S.S.,Huang, Z.,Park, H.-S.,Yu, J.-H.,Cá,novas, D.,Dyer, P.S. CBS Fungal Biodiversity Centre 2018 Studies in mycology Vol.91 No.-

<P><I>Aspergillus nidulans</I> has long-been used as a model organism to gain insights into the genetic basis of asexual and sexual developmental processes both in other members of the genus <I>Aspergillus</I>, and filamentous fungi in general. Paradigms have been established concerning the regulatory mechanisms of conidial development. However, recent studies have shown considerable genome divergence in the fungal kingdom, questioning the general applicability of findings from <I>Aspergillus</I>, and certain longstanding evolutionary theories have been questioned. The phylogenetic distribution of key regulatory elements of asexual reproduction in <I>A. nidulans</I> was investigated in a broad taxonomic range of fungi. This revealed that some proteins were well conserved in the <I>Pezizomycotina</I> (<I>e.g.</I> AbaA, FlbA, FluG, NsdD, MedA, and some velvet proteins), suggesting similar developmental roles. However, other elements (<I>e.g.</I> BrlA) had a more restricted distribution solely in the <I>Eurotiomycetes</I>, and it appears that the genetic control of sporulation seems to be more complex in the aspergilli than in some other taxonomic groups of the <I>Pezizomycotina</I>. The evolution of the velvet protein family is discussed based on the history of expansion and contraction events in the early divergent fungi. Heterologous expression of the <I>A. nidulans abaA</I> gene in <I>Monascus ruber</I> failed to induce development of complete conidiophores as seen in the aspergilli, but did result in increased conidial production. The absence of many components of the asexual developmental pathway from members of the <I>Saccharomycotina</I> supports the hypothesis that differences in the complexity of their spore formation is due in part to the increased diversity of the sporulation machinery evident in the <I>Pezizomycotina</I>. Investigations were also made into the evolution of sex and sexuality in the aspergilli. <I>MAT</I> loci were identified from the heterothallic <I>Aspergillus</I> (<I>Emericella</I>) <I>heterothallicus</I> and <I>Aspergillus</I> (<I>Neosartorya</I>) <I>fennelliae</I> and the homothallic <I>Aspergillus pseudoglaucus</I> (=<I>Eurotium repens</I>). A consistent architecture of the <I>MAT</I> locus was seen in these and other heterothallic aspergilli whereas much variation was seen in the arrangement of <I>MAT</I> loci in homothallic aspergilli. This suggested that it is most likely that the common ancestor of the aspergilli exhibited a heterothallic breeding system. Finally, the supposed prevalence of asexuality in the aspergilli was examined. Investigations were made using <I>A. clavatus</I> as a representative ‘asexual’ species. It was possible to induce a sexual cycle in <I>A. clavatus</I> given the correct <I>MAT1-1</I> and <I>MAT1-2</I> partners and environmental conditions, with recombination confirmed utilising molecular markers. This indicated that sexual reproduction might be possible in many supposedly asexual aspergilli and beyond, providing general insights into the nature of asexuality in fungi.</P>

Hypersurface Constrained Elasticae in Lorentzian Space Forms

Garay, &Oacute,scar J.,Pá,mpano, Á,lvaro,Woo, Changhwa Hindawi Limited 2015 Advances in mathematical physics Vol.2015 No.-

<P>We study geodesics in hypersurfaces of a Lorentzian space formM1n+1(c), which are critical curves of theM1n+1(c)-bending energy functional, for variations constrained to lie on the hypersurface. We characterize critical geodesics showing that they live fully immersed in a totally geodesicM13(c)and that they must be of three different types. Finally, we consider the classification of surfaces in the Minkowski 3-space foliated by critical geodesics.</P>

The SAURON project – XIX. Optical and near‐infrared scaling relations of nearby elliptical, lenticular and Sa galaxies

Falc&oacute,n‐,Barroso, J.,van de Ven, G.,Peletier, R. F.,Bureau, M.,Jeong, H.,Bacon, R.,Cappellari, M.,Davies, R. L.,de Zeeuw, P. T.,Emsellem, E.,Krajnović,, D.,Kuntschner, H.,McDermid, R. Blackwell Publishing Ltd 2011 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.417 No.3

<P><B>ABSTRACT</B></P><P>We present ground‐based MDM Observatory <I>V</I>‐band and <I>Spitzer</I>/InfraRed Array Camera 3.6‐<IMG src='/wiley-blackwell_img/equation/MNR_19372_mu1.gif' alt ='inline image'/>m‐band photometric observations of the 72 representative galaxies of the SAURON survey. Galaxies in our sample probe the elliptical E, lenticular S0 and spiral Sa populations in the nearby Universe, both in field and cluster environments. We perform aperture photometry to derive homogeneous structural quantities. In combination with the SAURON stellar velocity dispersion measured within an effective radius (σ<SUB>e</SUB>), this allows us to explore the location of our galaxies in the colour–magnitude, colour–σ<SUB>e</SUB>, Kormendy, Faber–Jackson and Fundamental Plane scaling relations. We investigate the dependence of these relations on our recent kinematical classification of early‐type galaxies (i.e. slow/fast rotators) and the stellar populations. Slow rotator and fast rotator E/S0 galaxies do not populate distinct locations in the scaling relations, although slow rotators display a smaller intrinsic scatter. We find that Sa galaxies deviate from the colour–magnitude and colour–σ<SUB>e</SUB> relations due to the presence of dust, while the E/S0 galaxies define tight relations. Surprisingly, extremely young objects do not display the bluest (<I>V</I>−[3.6]) colours in our sample, as is usually the case in optical colours. This can be understood in the context of the large contribution of thermally pulsing asymptotic giant branch stars to the infrared, even for young populations, resulting in a very tight (<I>V</I>−[3.6])–σ<SUB>e</SUB> relation that in turn allows us to define a strong correlation between metallicity and σ<SUB>e</SUB>. Many Sa galaxies appear to follow the Fundamental Plane defined by E/S0 galaxies. Galaxies that appear offset from the relations correspond mostly to objects with extremely young populations, with signs of ongoing, extended star formation. We correct for this effect in the Fundamental Plane, by replacing luminosity with stellar mass using an estimate of the stellar mass‐to‐light ratio, so that all galaxies are part of a tight, single relation. The new estimated coefficients are consistent in both photometric bands and suggest that differences in stellar populations account for about half of the observed tilt with respect to the virial prediction. After these corrections, the slow rotator family shows almost no intrinsic scatter around the best‐fitting Fundamental Plane. The use of a velocity dispersion within a small aperture (e.g. <I>R</I><SUB>e</SUB>/8) in the Fundamental Plane results in an increase of around 15 per cent in the intrinsic scatter and an average 10 per cent decrease in the tilt away from the virial relation.</P>

OGLE-2016-BLG-0596Lb: A High-mass Planet from a High-magnification Pure-survey Microlensing Event

Mr&oacute,z, P.,Han, C.,Udalski, A.,Poleski, R.,Skowron, J.,Szymań,ski, M. K.,Soszyń,ski, I.,Pietrukowicz, P.,Kozłowski, S.,Ulaczyk, K.,Wyrzykowski, Ł.,Pawlak, M.,Albrow, M. D.,Cha, S.-M.,Ch American Institute of Physics 2017 The Astronomical journal Vol.153 No.4

<P>We report the discovery of a high mass ratio planet, q = 0.012, i.e., 13 times higher than the Jupiter/Sun ratio. The host mass has not yet been measured but can be determined or strongly constrained from adaptive optics imaging. The planet was discovered in a small archival study of high-magnification events in pure-survey microlensing data, which was unbiased by the presence of anomalies. The fact that it was previously unnoticed may indicate that more such planets lie in archival data and could be discovered by a similar systematic study. In order to understand the transition from predominantly survey+followup to predominately survey-only planet detections, we conduct the first analysis of these detections in the observational (s, q) plane. Here s is the projected separation in units of the Einstein radius. We find some evidence that survey+followup is relatively more sensitive to planets near the Einstein ring, but that there is no statistical difference in sensitivity by mass ratio.</P>

HPLC enantioseparation of &bgr;²-homoamino acids using crown ether-based chiral stationary phase

Berkecz, R&oacute,bert,Ilisz, Istvá,n,Misicka, Aleksandra,Tymecka, Dagmara,Fü,lö,p, Ferenc,Choi, Hee Jung,Hyun, Myung Ho,Pé,ter, Antal WILEY-VCH Verlag 2009 Journal of Separation Science Vol.32 No.7

<P>RP high-performance liquid chromatographic methods were developed for the enantioseparation of eleven unusual β<SUP>2</SUP>-homoamino acids. The underivatized analytes were separated on a chiral stationary phase containing (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid as chiral selector. The effects of organic (alcoholic) and acidic modifiers, the mobile phase composition and temperature on the separation were investigated. The structures of the substituents in the α-position of the analytes substantially influenced the retention and resolution. The elution sequence was determined in some cases: the S enantiomers eluted before the R enantiomers.</P>