Miracle-dz/UniFAR-FTUs huggingface dataset:
Molecular Oxygen Reduction in PEM Fuel Cells: Evidence for the Simultaneous Presence of Two Active Sites in Fe-Based Catalysts

Three catalysts for the electroreduction of oxygen have been prepared by pyrolyzing between 400 and 1000 °C two iron precursors (Fe acetate or Fe porphyrin) adsorbed on a synthetic carbon made from the pyrolysis of PTCDA (perylene tetracarboxylic dianhydride) in a H2/NH3/Ar atmosphere. One Fe loading (0.2 wt %) has been used for the catalyst made from the salt precursor. Two Fe loadings (0.2 and 2.0 wt %) have been used for the catalyst made from the porphyrin precursor. These three catalysts have been analyzed by ToF SIMS and RDE (or GDE) in order to find correlations between ions detected by ToF SIMS and the catalytic activity. These correlations provide information about the number and the structure of the catalytic sites, which are active in these materials. By following the variation of FeNxCy+ ions, it is found that (i) two different catalytic sites exist simultaneously in all catalysts made with the Fe salt or the Fe porphyrin; (ii) one site, named FeN4/C, is at the origin of three families of FeNx.
Synthesis in Pure Ethanol and Characterization of Nanosized Calcium Phosphate Fluoroapatite

A fluoridated calcium phosphate CPF powder was synthesized in anhydrous ethanol starting from Ca(OEt)2, H3PO4, and NH4F reagents. Two other materials, CP and CF, were also obtained without, respectively, the fluoride and the phosphate source to understand the mechanism of formation of the CPF solid. The vacuum-dried precipitate CF was fully crystallized and identified as calcium fluoride CaF2. In contrast, the vacuum-dried precipitates CPF and CP, which have Ca/P ratios close to 1.67, were amorphous to XRD. The amorphous sample CPF had the same chemical composition as that of a fluoroapatite Ca10(PO4)6F2 compound. The XPS spectroscopy showed that this amorphous solid CPF was homogeneous and was not a mixture of Ca9(PO4)6 and CaF2 phases. The thermal behavior was studied by TGA, DTA, XRD, SEM, and IR spectroscopy. The analyses confirmed the homogeneity of the amorphous CPF precipitate, which crystallized, at 460 °C into a pure fluoroapatite phase. The starting nanosized CPF powder has shown its high reacti.
Climate change and population genetic structure of marine species

Climate change influences populations by reducing or extirpating local populations, by disrupting patterns of migration and by shifting geographical distributions. These events can affect genetic population structure in several ways. Molecular markers have been used in numerous population genetic and phylogeographical studies of marine species and have detected population responses to climate change in the last few decades, such as range expansions, adaptative shifts and declines or increases in abundance. Little is known, however, about the molecular and physiological basis of adaptive responses to climate change in marine Mediterranean species. The Mediterranean Sea ecosystem is a ‘living laboratory’ with native species that are challenged by environmental change and by invasive species and a ‘gene-climate’ approach should be adopted as a way of focusing on the relationship between climate warming and genetic diversity.
Comparison of the Resuspension Behavior Between Liquid and Solid Aerosols

Resuspension of an aerosol from solid surfaces is an important phenomenon. The resuspension behaviors of solid aerosols and liquid aerosols are not necessarily the same. A whole solid particle detaches from the surface when the removal force is sufficient, while a portion of a droplet may detach even if the removal force is insufficient to detach the whole droplet. The objective of this article is to compare the resuspension behaviors between liquid and solid aerosols from a solid surface. Polystyrene particles and glycerol in micron sizes were generated and deposited on substrates. Two types of experiments, centrifugal detachment and vibrational resuspension, were carried out. In the centrifuge experiment, a constant removal force field was provided. Larger droplets split into smaller portions during detachment. In terms of the fraction remaining, the adhesion of the liquid aerosol has the same order of magnitude to that of the solid particle. A theoretical analysis analogous to the case of pendent drop was carried out, and the theoretical prediction agreed well with the experimental result. In the vibration experiment, a sinusoidal force field was applied. A same fraction of the solid particle detached with a much smaller force in vibration experiment than in the centrifuge experiment, whereas no resuspension was observed for liquid droplets. The adhesive forces of the liquid and solid aerosols have the same order of magnitude in the centrifuge case, but in the vibration case their adhesive forces have much greater difference. It poses a necessity for further investigation. Copyright 2013 American Association for Aerosol Research
Investigation on FTIR Spectrum of Barium Titanate Ceramics Doped with Alkali Ions

Additives play an important role in improving the properties of ferroelectric barium titanate. Barium titanate ceramics doped with alkali were prepared. These additives replaced other cations and changed the structure of the crystal. The interaction between different ions in the material affected the related vibration of the crystal lattices. Fourier transformation infrared spectroscopy(FTIR) measurement was carried out in order to investigate the effect. Absorption peaks of doped barium titanate ceramics were different from that of pure barium titanate. The corresponding absorption peak shifted to a higher wave number when the Ti-O bonds were enhanced. On the other hand, the absorption peak moved to a lower frequency when Ti-O octahedrons were distorted.
Silver nanoparticles: green synthesis, self-assembled nanostructures and their application as SERS substrates

In this paper, silver nanoparticles were synthesized using citrus peel extracts from species such as Citrus sinensis (orange fruit, AgNP-Ora), Citrus reticulata (tangerine fruit, AgNP-Tan), and Citrus aurantifolia (lemon fruit, AgNP-Lem). The absorption spectra of the AgNP-Ora and AgNP-Tan colloids show localized surface plasmon resonance (LSPR) bands at 445 and 423 nm, respectively. For the same synthesis method, a low intensity LSPR band for AgNP-Lem is observed, indicating a low yield of this reaction. However, the transmission electron microscopy images show that the colloid prepared using lemon extract also presents AgNP larger than 5 nm (5–55 nm), which exhibit plasmonic properties. The synthesized silver nanoparticles are spherical in shape and are highly crystalline, and they were self-assembled on NH2-modified glass slides, forming AgNP aggregate substrates for all the three prepared silver colloids. We also explored the SERS activity of the AgNP substrates using 10−6 mol L−1 solutions of 4-aminobenzenethiol, rhodamine 6G, and methylene blue as Raman probe molecules. It was possible to detect with a high signal-to-noise ratio the SERS spectral pattern of all probe molecules on AgNP substrates. This simple, low cost, and greener method for synthesizing silver nanoparticles may be valuable in future studies about SERS sensor development and can be extended to catalytic applications.
Cryofixation of plant tissues without pretreatment

Root tips from Sorghum and Dahlia were frozen without cryoprotection by dipping into nitrogen slush, rapid immersion in liquid propane and by the high‐pressure method. Structural preservation of the samples was studied using freeze‐fracture (FF) and freeze‐substitution (FS) techniques for electron microscopy. It was found that most of the organelles were disrupted by freezing in nitrogen slush and that only the boundary beween the cytoplasm and the vacuole remained visible. If the samples were frozen by rapid immersion in liquid propane, small membraneous organelles, such as dictyosomes, were preserved in peripheral regions of the rhizodermal cells up to 10 μm below the surface of the tissue. Specimens frozen by the high‐pressure freezing technique showed good ultrastructural preservation throughout the tissues up to a depth of more than 100 μm.
Morphology of a TiO2 Photocatalyst (Degussa, P-25) Consisting of Anatase and Rutile Crystalline Phases

Abstract The TiO 2 powder (Degussa, P-25), which is a standard material in the field of photocatalytic reactions, contains anatase and rutile phases in a ratio of about 3 : 1. Transmission electron microscopy showed that the anatase and rutile particles separately form their agglomerates. The average sizes of the anatase and rutile elementary particles are 85 and 25 nm, respectively. Diffuse reflectance spectra of the TiO 2 powder were successfully traced by physically mixing pure anatase and rutile particles in a ratio of 3 : 1. By the HF treatment of the TiO 2 powder, pure rutile particles were isolated. All these results indicate that the rutile phase does not exist as an overlayer on the surface of anatase particles, but it exists separately from anatase particles. We also found that photocatalytic oxidation of naphthalene is inefficient on pure anatase and rutile powders. However, the reaction is very efficient on the P-25 powder, as well as on a mixture of pure anatase and rutile particles. Under the conditions of the photocatalytic reactions, the anatase and rutile agglomerates are considered to be decomposed, and the anatase and rutile particles are in contact, leading to a synergy effect.
Control of micro- and nanopatterns of octadecyltrimethoxysilane monolayers using nanoimprint lithography and atmospheric chemical vapor deposition

Octadecyltrimethoxysilane (OTMS) self-assembled monolayers have been grafted on micrometric and nanometric areas of SiO2∕Si substrates using a process combining nanoimprint lithography and atmospheric chemical vapor deposition. The optimization of the process has lead to monolayer square patterns of OTMS with lateral sizes ranging from 2μm down to 50nm. Their coverage uniformity extends on several square millimeters. Their coverage density can be accurately tuned by the deposition time.
Voltammetry in (toluene)3-tetrabutylammonium tetrafluoroborate, a novel liquid hydrocarbon electrolyte

Etude de la reduction de perylene, pyrene, naphtacene et anthraquinone sur une electrode de platine recouverte de mercure, dans le toluene-tetrafluoroborate de tetrabutyl ammonium (rapport molaire 3:1)
The influence of surface and sub-surface application methods for pig slurry on herbage yields and nitrogen recovery

Experiments were conducted on a grassland site at Wrest Park, Silsoe, Bedfordshire between 1987 and 1989, to compare herbage yields from slurry applied by deep and shallow injection, low trajectory and conventional vacuum tanker methods. Slurry application rates for all spreaders were calibrated at 86 ± 5 t ha-1, an equivalent of c. 200 kg NH4+-N ha-1 applied in autumn or in spring. As expected, herbage yields following spring applications were higher than from autumn applications, with average mineral fertilizer equivalents of 122 and 89 kg N ha-1 respectively. Yields from the conventional and low trajectory spreaders showed no consistent differences. However, in both years, first cut yields from plots were significantly lower (P < 0·05) where slurry had been injected than where surface applications had been used by an average of 0·7 t DM ha-1. Subsequent cuts in 1988 demonstrated higher residual effects from injection so that annual total yields were similar from all slurry applications irrespective of spreader type. Analysis of N content revealed high N levels in herbage from deep injection plots. Mean concentrations of N in the herbage, expressed as a percentage of the dry matter, were 1·43 for surface treatments and 1·79 for deep injection in 1988, and 1·84 for surface treatments, 2·13 for shallow injection and 2·68 for deep injection in 1989.
Analyse de la distribution de valeur dans la filière laitière

Depuis dix ans, le prix du lait d’industrie paye aux producteurs diminue. En reponse a cette situation preoccupante, l’etude «distribution de valeur en filiere» propose des elements d’analyse et des pistes concretes pour ameliorer le retour de valeur aux producteurs. Quelle que soit la filiere agricole, les prix payes au producteur different fortement selon le circuit de vente, la differenciation du produit (differencie versus generique) percue par le consommateur et aussi par le distributeur, et la forme de gouvernance qui lie le producteur a l’acheteur. Les regles de fixation des marges par la grande distribution et les transformateurs ne sont pas transparentes. Les asymetries d’information entre les differents acteurs jouent en defaveur du producteur. Plus les producteurs et les transformateurs reussissent a differencier leurs produits et a convaincre les consommateurs de payer plus cher, plus la part de la valeur prelevee par les distributeurs augmente. De plus, les excedents et les produits a faible valeur ajoutee pesent sur la valeur globale de la filiere. L’etude met en lumiere l’impact de la structure de gouvernance sur le retour de valeur aux producteurs. La demande des consommateurs pour des prix «equitables pour les paysans» augmente et pourrait bientot peser suffisamment sur l’image des transformateurs et des distributeurs pour les convaincre d’integrer systematiquement cet aspect dans leurs criteres de performance.
Real-Time Measurement of Correlated Size and Composition Profiles of Individual Atmospheric Aerosol Particles

In this paper, the unique real-time measurement capabilities of aerosol time-of-flight mass spectrometry (ATOFMS) for characterizing atmospheric aerosol particles are demonstrated. ATOFMS is used to obtain the aerodynamic size and chemical composition of individual aerosol particles sampled directly into the instrument from outdoors. Such measurements are made in-situ by combining a unique dual-laser aerodynamic particle sizing system to size and track individual particles through the instrument and laser desorption/ionization time-of-flight mass spectrometry to obtain correlated single particle composition data. At typical ambient concentrations, the size and chemical composition of 50−100 particles per minute can be measured (up to 600 per minute at high particle concentrations). Presented here for the first time are compositionally resolved particle size distributions of ambient aerosol particles, showing definitive size/composition correlations. A goal of these studies is to ultimately couple data obt.
The electronic spectrum of silicon methylidyne (SiCH), a molecule with a silicon–carbon triple bond in the excited state

The A 2Σ+–X 2Πi transition of jet-cooled silicon methylidyne, SiCH, has been recorded by laser-induced fluorescence in the 850–600 nm region. The radical was produced in an electric discharge using tetramethylsilane as the precursor. Fifteen cold bands of SiCH and 16 bands of SiCD have been assigned vibrationally, giving the upper state frequencies as v2′=715/558 cm−1 and v3′=1168/1127 cm−1 for SiCH/SiCD. Rotational analysis of the 000 and 303 bands for each isotopomer has given the following molecular structures: r0″(Si–C)=1.692 52(8), r0″(C–H)=1.0677(4), r0′(Si–C)=1.6118(1), and r0′(C–H)=1.0625(5) A. The silicon–carbon bond length in the X 2Π ground state of SiCH (electron configuration …σ2π3) is typical for a Si=C double bond; in the A 2Σ+ excited state (…σ1π4) it corresponds to a triple bond. This work provides the first experimental measurement of the length of the carbon–silicon triple bond.
Barbiturates with hydrogen-bonded layer and framework structures

Four N–H⋯OC bonded structures for 5,5-substituted derivatives of barbituric acid are reported, which are distinct from the eight fundamental types that have been previously described. The N–H⋯OC-bonded layer structures L-4, L-5 and L-6 are present in crystal polymorphs of 5-(2-bromoallyl)-5-isopropyl barbituric acid (L-4: 1, noctal), 5,5-dichlorobarbituric acid (L-6: 2a, L-5: 2b) and 5,5-dibromobarbituric acid (L-5: 3a). The monoclinic polymorph (3b) of the dibromo compound contains the framework F-2. In each case, the essential building block consists of two molecules which are doubly N–H⋯OC-bonded via a central R22(8) ring. The L-4 structure is closely related to the common 1D ladder topology C-4. It serves also as a building unit for the L-5 sandwich structure. The essential rings of L-4 and L-6 have the same graph-set descriptor R66(28) but are topologically distinct from one another. In the F-2 framework, ten molecules are linked together to give an L-shaped R1010(48) ring. The IR spectra of the crystal forms 1, 2a–b and 3a–b are discussed and a previously established classification scheme correlating the H-bonding of barbiturates with their IR characteristics is extended.
Microarrays, Genexpressionsanalyse und Bioinformatik

In den letzten Jahren wurden grose Fortschritte bei der Entwicklung von Ultrahochdurchsatz-Techniken zur Datenerfassung in den Biowissenschaften erzielt. Schnelle Sequenzierungstechniken ermoeglichten die nahezu vollstaendige Entschluesselung des menschlichen Genoms und einiger weiterer Modellorganismen. Der naechste konsequente Schritt in Richtung auf ein hollistisches Verstaendnis des synergischen Zusammenspiels der molekularen Bestandteile des Organismus im Rahmen der funktionellen Genomik ist die Entschluesselung des Transkriptoms und des Proteoms. Eine hierfuer geeignete Technik, besonders zur parallelen Massendatenerfassung der RNA-Mengen sehr vieler Gen-Transkripte, ist die in den letzten Jahren weiter perfektionierte Microarray-Technik. Die Auswertung der hierbei anfallenden sehr grosen Datenmengen stellt die Wissenschaft vor Probleme, denen durch eine weitergehende Automatisierung, auch des Auswertungsprozesses, begegnet wird.
DECOMPOSITION IN AN OMBROTROPHIC BOG AND A MINEROTROPHIC FEN IN MINNESOTA

Using mass-loss and CO2-evolution techniques, we evaluated the decomposition of peat in an ombrotrophic bog in northern Minnesota. We also compared decomposition potentials, using uniform material (cellulose), between the bog and a nearby minerotrophic fen. Mass loss decreased with increasing depth in the peat due to environmental and substrate limitations. Mass-loss from cellulose was greater in the fen than in the bog.
Arsenobetaine and other arsenic species in mushrooms

Arsenic species in arsenic accumulating mush- rooms (Sarcosphaera coronaria, Laccaria amethystina, Sarcodon imbricatum, Entoloma lividum, Agaricus haemorrhoidaius, Agaricus placomyces, Lycoperdon perlatum) were determined. HPLC/ICP MS and ion-exchange chromatogra- phy–instrumental neutron activation analysis (NAA) combinations were used. The remarkable accumulator Sarcosphaera coronaria (up to 2000 mg As kg−1 dry wt) contained only methylarsonic acid, Entoloma lividum only arsenite and arsenate. In Laccaria amethystina dimethylarsinic acid was the major arsenic compound. Sarcodon imbricatum and the two Agaricus sp. were found to contain arsenobetaine as the major arsenic species, a form which had previously been found only in marine biota. Its identification was confirmed by electron impact MS.
Submicron Dispersions of Hexosomes Based on Novel Glycerate Surfactants

Glycerate-based surfactants are a new class of swelling amphiphiles which swell to a finite degree with water. Among this class of surfactants, oleyl (cis-octadec-9-enyl) glycerate is very similar in structure to a well characterized mesophase-forming lipid, glyceryl monooleate (GMO). Despite the similar structural characteristics, a subtle change in connectivity of the ester bond substantially alters the binary surfactant-water phase behaviour. Whereas the phase behaviour of GMO is diverse and dominated by cubic phases, the phase behaviour of oleyl glycerate and a terpenoid analogue phytanyl (3,7,11,15-tetramethyl-hexadecane) glycerate is much simplified. Both exhibit an inverse hexagonal phase (H-II), which is stable to dilution with excess water, and an inverse micellar phase (L-II) at ambient temperatures. The inverse hexagonal phases formed by oleyl glycerate and phytanyl glycerate have been characterized using SAXS. Analogous to GMO cubosomes, the inverse hexagonal phase of phytanyl glycerate has been dispersed to form hexagonally facetted particles, termed hexosomes, whose structure has been verified using cryo-TEM.
Computational Fluid Dynamics Simulation of Three-Dimensional Liquid Flow and Mass Transfer on Distillation Column Trays

This paper presents a three-dimensional computational fluid dynamics (CFD) model for describing the liquid-phase flow and concentration distribution on a distillation column tray. Both volume fractions of gas and liquid as well as the interfacial forces and the interphase mass-transfer item Sc are considered in modeling. Simulations of three-dimensional liquid flow and the concentration distribution were carried out on both a single tray and all trays of a distillation column with 10 sieve trays under total reflux. The simulations were performed by using software Star-CD. The prediction by the present model for liquid flow on a single tray was confirmed by the experimental measurement reported by Solari and Bell (AIChE J. 1986, 32, 640) and the simulation by Gesit et al. (AIChE J. 2003, 49, 910) on a 1.22-m-diameter sieve tray. The predicted overall column efficiency resulting from the concentration distribution on each tray for the cyclohexane−heptane separation in a 10-tray distillation column under tot.
Vibrational relaxation on metal surfaces : molecular-orbital theory and application to CO/Cu(100)

A nonempirical theory of vibrational relaxation at metal surfaces via nonadiabatic coupling to conduction electrons is presented. Using a single determinant Hartree–Fock (HF) description of the electronic states of the system, an expression for the lifetime of an excited vibration is obtained. Under certain additional assumptions, all the quantities necessary to calculate the lifetime can be obtained from the results of ab initio HF calculations on cluster models of the adsorbate‐metal system. As a practical test of this procedure, the lifetime of the excited v=1 vibrational state of CO on Cu(100) is calculated using clusters of 6, 10, and 14 copper atoms. Results ranging between 1.1 and 3.5 ps are obtained, with our preferred procedure yielding 1.7 ps for the largest cluster, in good agreement with experiment. Extensions of this approach may also be valuable for treating other nonadiabatic phenomena at metal surfaces.
CRYSTAL ORIENTATION ANISOTROPY OF EPITAXIAL Pb(Mg1/3Nb2/3)O3-PbTiO3 THICK FILMS GROWN BY MOCVD

ABSTRACT (100), (110), and (111)-oriented epitaxial Pb(Mg1/3Nb2/3)O3 PbTiO3 (PMN-PT) films with a thickness of 2–3 μm were grown on (100) c SrRuO3//(100)SrTiO3, (110) c SrRuO3//(110)SrTiO3, and (111) c SrRuO3//(111)SrTiO3 substrates, respectively, by pulsed-metalorganic chemical vapor deposition (MOCVD). Epitaxial films with different three crystal orientations were successfully grown on these substrates irrespective of PT content. Relative dielectric constant, ϵr, took the maximum at PT content around 0.40 for all orientations. Remanent polarization, P r, and coercive field, E c, increased with increasing PT content, and had a small peak at PT content around 0.45 and increased again. Longitudinal field-induced strain also showed the maximum against the PT content for all crystal orientations. However, PT content took maximum longitudinal field-induced strain was 0.40 for {100} orientation, while was 0.45 for {110} and {111} orientations. In addition, its absolute value of longitudinal field-induced strain was much smaller than reported ones for sintered bodies and single crystals. The large crystal anisotropy on electrical properties reported for the single crystal was hardly observed even in epitaxially grown films. This suggests the electrical properties were strongly influenced by the stress from the substrate.