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Using a solution technique, tetraethylorthosilicate cross-linked hybrid polyvinyl alcohol) membrane was prepared. The membrane was further incorporated with 0, 10, 20, and 30 mass% of mesoporous carbon and the membranes thus obtained were designated as M-1, M-2, M-3, and M-4, respectively. The physico-chemical properties of these membranes were investigated using Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, differential scanning calorimetry, thermogravimetry analysis, and scanning electron microscopy. The effects of mesoporous carbon and feed composition on pervaporation performance of the membranes were systematically investigated. The membrane M-4 exhibited the highest separation factor of 4,082 with a flux of 1.93 x [10.sup.-2] kg/ m h at 30[degrees]C for 10 mass% of water in the feed. Total flux and flux of water are overlapping each other, manifesting that these membranes could be used to break the azeotropic point of water-isopropanol mixtures effectively. From the temperature dependent diffusion and permeation values, the Arrhenius activation parameters were estimated. The positive heat of sorption values was obtained for M-1, M-2, and M-3, suggesting that Henry's mode of sorption is predominant, giving an endothermic contribution. On the contrary, membrane M-4 exhibited negative [DELTA][H.sub.S] value suggesting that the sorption process was dominated by exothermic contribution., INTRODUCTION Pervaporation (PV) is a promising technique, which involves the phenomenon of both permeation and evaporation [1, 2], The technical feasibility of PV for mass transport mainly depends on membrane [...]

The ground state and low-lying excited states of the CCCN radical and its ions have been investigated systematically using the complete active space self-consistent field (CASSCF) and multi-configuration second-order perturbation theory (CASPT2) methods in conjunction with the ANO-RCC-TZP basis set. The calculated results show that the state [1.sup.2][Σ.sup.+] has the lowest CASPT2 energy among the electronic states. By means of the geometric optimization of this radical, it could be found that the molecule exhibits linear structure, with the bond lengths [R.sub.1] = 1.214 Å, [R.sub.2] = 1.363 Å, [R.sub.3] = 1.162 Å, which are very close to the experimental values. The calculated vertical excitation energies and the corresponding oscillator strengths show that there are three relatively strong peaks at energies 0.63, 4.04, and 5.49 eV, which correspond to the transitions [1.sup.2][Σ.sup.+] [right arrow] [1.sup.2]Π, [1.sup.2][Σ.sup.+] → [2.sup.2]Π, and [1.sup.2][Σ.sup.+] → [2.sup.2][Σ.sup.+], respectively. Additionally, the electronic configuration and the harmonic vibration frequencies of each state are also investigated. Key words: CCCN radical, ground state, low-lying excited states, complete active space self-consistent field, multi-configuration second-order perturbation theory. Nous etudions systematiquement le fondamental et les etats excites de basse energie du radical CCCN et de ses ions, en utilisant le champ auto-coherent d'espace actif complet (CASSCF) et la methode de perturbation du deuxieme ordre multiconfigurations (CASPT2) en conjonction avec l'ensemble de base ANO-RCC-TZP. Les resultats du calcul montrent que l'etat [1.sup.2][Σ.sup.+] a l'energie CASPT2 la plus basse parmi les etats electroniques. Par optimisation geometrique de ce radical, on trouve que la molecule a une structure lineaire avec une longueurs de liaison [R.sup.1] = 1.214 Å, [R.sup.2] = 1.363 Å et [R.sub.3] = 1.162 Å, qui sont tres pres des valeurs experimentales. Les energies d'excitation calculees et les valeurs correspondantes des forces d'oscillateur montrent qu'il y a trois raies assez fortes a 0.63, 4.04 et 5.49 eV, qui correspondent aux transitions [1.sup.2][Σ.sup.+] → [1.sup.2]Π, [1.sup.2][Σ.sup.+] → [2.sup.2]Π et [1.sup.2][Σ.sup.+] → [2.sup.2][Σ.sup.+], respectivement. Nous etudions egalement la configuration electronique et les frequences de vibration harmonique de chaque etat. [Traduit par la Redaction] Mots-cles: radical CCCN, niveau fundamental, etats excites de basse energie, champ auto-coherent d'espace actif complet, theorie de perturbation du second ordre multi-configurations., 1. Introduction With the development of astrophysics, the spectroscopic studies of hetero-atom doped carbon chain radical has received widespread attention in the past three decades. [1-10] As the earliest discovered [...]

Natural organic matter (NOM) is a highly active component of soils and sediments, and plays all important role in global C cycling. However, NOM has defied molecular-level structural characterization, owing to variations along the decomposition continuum and its existcnce as highly functionalized polyelectrolytes. We conducted a conrprehensivc systematic overview of spectral signatures and peak positions of major organic molecules that occur as part of NOM using near-edge x-ray absorption fine structure (NEXAFS) spectroscopy. The spectra of carbohydrates and amino sugars show resonances between 289.10 and 289.59 eV, attributed to 1s-3p/[[sigma].sup.*] transitions of O-alkyl (C-OH) moieties. They also exhibited distinct peaks between 288.42 and 288.74 eV, representing C 1s-[[pi].sup.*.sub.C=O] transition from COOH functionalities. Amino acids produced a strong signal around 288.70 eV which can be identified as a C [[pi].sup.*.sub.C=O] transition of carboxyl/carbonyl (COOH/ COO-) structures. Spectral features near 285.29 eV were ascribed to C [[pi].sup.*.sub.C=C] transition of ring structure of aromatic amino acids, while spectra between 287.14 and 287.86 eV were attributed to C [[pi].sup.*.sub.C-H] and C 1s-[[sigma].sup.*.sub.C-H/]3p Rydberg-like excitations from CH and C[H.sub.2] groups. Phenols and benzoquinone produced strong resonances between 285.08 and 285.37 eV, attributed to the [[pi].sup.*] orbital of C (C 1s-[[pi].sup.*.sub.C=C]) atoms connected to either C or H (C-H) in the aromatic ring. The next higher excitation common to both phenols and quinone appeared between 286.05 and 286.35 eV, and could be associated with C 1s[[pi].sup.*.sub.C=C] transitioxrs of aromatic C bonded to O atom in phenols, and to C 1s-[[pi].sup.*.sub.C=O] transitions from aromatic C connected to O atom (C-OH) in phenols or to a C=O in p-benzoquinone and some phenols with carbonyl structures, respectively. Nucleobases exhibited complex spectral features with pronounced resonances between 286.02 and 286.84 eV and between 288.01 and 288.70 eV. Molecular markers for black C (benzenecarboxylic acid and biphenyl-4,4'-dicarboxylic acid) exhibit sharp absorption bands between 285.01 and at 285.43 eV, possibly from C 1s-[[pi].sup.*.sub.C=C] transition characteristic of C-H sites or unsaturated C (C=C) on aromatic ring structures. These aromatic carboxylic acids also exhibit broad peaks between 288.35 and 288.48 eV, reflecting C [[pi].sup.*.sub.C=O] transition of carboxyl functional groups bonded to unsaturated C. This investigation provides a more comprehensive NEXAFS spectral library of biogeochemically relevant organic C compounds. The spectra of these reference organic compounds reveal distinct spectral features and peak positions at the C K-edge that arc characteristic of the molecular orbitals bonding C atoms. Detailed structural information can be derived from these distinctive spectral features that could be used to build robust peak assignment criteria to exploit the chemical sensitivity of NEXAFS spectroscopy for in situ molecular-level spatial investigation and fingerprinting of complex organic C compounds in environmental samples. Abbreviations: EDX, energy dispersive x-ray; NEXAFS, near-edge x-ray absorption fine structure spectroscopy; NOM, natural organic matter; SEM, scanning electron microscopy; STXM, scanning transmission x-ray microscopy; TEM transmission electron microscope: XPS, x-ray photoelectron spectroscopy. doi: 10.2136/sssaj2008.0228

The effect of carbon mixing on the perpendicular magnetization of magnetron sputtered FePt thin films on our newly developed underlayer of Pt/MgO(p) composite thin-film was studied using magnetic property measurement and X-ray diffraction, and TEM microscopy. Micromagnetic simulation was carried out to study the effect of texture on the perpendicular coercivity. Unlike a general expectation, the mixing of FePt with carbon led to a significant enhancement in the perpendicular magnetization. The maximum enhancement of perpendicular magnetization was observed at about 22 vol.% of carbon, where carbon amorphous film started to completely enclose the individual FePt grains. This was because the epitaxial growth and thus perpendicular texture of ordered FePt grains were maximized in the isolated grain structure due to a maximum relaxation of coherency strain for epitaxial growth. The simulation showed that the enhancement of perpendicular texture can largely increase the perpendicular coercivity of FePt:C thin film. Index Terms--Epitaxial growth, FePt:C magnetic thin films, perpendicular magnetization, texture.

High-resolution [delta][sup.13]C data of organic carbon from a continuous section of the Late Ordovician-Early Silurian reveal two positive [delta][sup.13]C excursions that are associated with the mass extinction in South China. The first stratigraphic [delta][sup.34]S measurements on pyrite tied to well-established biostratigraphy indicate a large perturbation of the sulfur cycle, consistent with major sea-level changes related to the glaciation. The elevated [delta][sup.34]S values of pyrites and a large, short-lived negative [delta][sup.34]S excursion of ~20[per thousand] associated with the decay of the glaciation suggest deep-water anoxia during the Hirnantian Stage, in contrast to the conventional view that the global oceans were oxygenated. We suggest that deep-water anoxia may have contributed to the Late Ordovician mass extinction in South China and possibly elsewhere.

For over a century, chemical transformations of benzene derivatives have been guided by the high selectivity for electrophilic attack at the ortho/para positions in electron-rich substrates and at the meta position in electron-deficient molecules. We have developed a copper-catalyzed arylation reaction that, in contrast, selectively substitutes phenyl electrophiles at the aromatic carbon--hydrogen sites meta to an amido substituent. This previously elusive class of transformation is applicable to a broad range of aromatic compounds.

We investigated carbon acquisition by the [N.sub.2]-fixing cyanobacterium Trichodesmium IMS101 in response to C[O.sub.2] levels of 15.1, 37.5, and 101.3 Pa (equivalent to 150, 370, and 1000 ppm). In these acclimations, growth rates as well as cellular C and N contents were measured. In vivo activities of carbonic anhydrase (CA), photosynthetic [O.sub.2] evolution, and C[O.sub.2] and HC[O.sup.-.sub.3] fluxes were measured using membrane inlet mass spectrometry and the [sup.14]C disequilibrium technique. While no differences in growth rates were observed, elevated C[O.sub.2] levels caused higher C and N quotas and stimulated photosynthesis and [N.sub.2] fixation. Minimal extracellular CA (eCA) activity was observed, indicating a minor role in carbon acquisition. Rates of C[O.sub.2] uptake were small relative to total inorganic carbon (Ci) fixation, whereas HC[O.sup.-.sub.3] contributed more than 90% and varied only slightly over the light period and between C[O.sub.2] treatments. The low eCA activity and preference for HC[O.sup.-.sub.3] were verified by the [sup.14]C disequilibrium technique. Regarding apparent affinities, half-saturation concentrations ([K.sub.1/2]) for photosynthetic [O.sub.2] evolution and HC[O.sup.-.sub.3] uptake changed markedly over the day and with C[O.sub.2] concentration. Leakage (C[O.sub.2] efflux : Ci uptake) showed pronounced diurnal changes. Our findings do not support a direct C[O.sub.2] effect on the carboxylation efficiency of ribulose-l,5-bisphosphate carboxylase/oxygenase (RubisCO) but point to a shift in resource allocation among photosynthesis, carbon acquisition, and [N.sub.2] fixation under elevated C[O.sub.2] levels. The observed increase in photosynthesis and [N.sub.2] fixation could have potential biogeochemical implications, as it may stimulate productivity in N-limited oligotrophic regions and thus provide a negative feedback on rising atmospheric C[O.sub.2] levels.

The number of biological/biomedical applications that require AMS to achieve their goals is increasing, and so is the need for a better understanding of the physical, morphological, and structural traits of high quality of AMS targets. The metrics of quality included color, hardness/ texture, and appearance (photo and SEM), along with FT-IR, Raman, and powder X-ray diffraction spectra that correlate positively with reliable and intense ion currents and accuracy, precision, and sensitivity of fraction modem ([F.sub.m]). Our previous method produced AMS targets of gray-colored iron--carbon materials (ICM) 20% of the lime and of graphite-coated iron (GCI) 80% of the time. The ICM was hard, its FT-IR spectra lacked the [sp.sup.2] bond, its Raman spectra had no detectable G' band at 2700 [cm.sup.-1], and it had more iron carbide ([Fe.sub.3]C) crystal than nanocrystalline graphite or graphitizable carbon (g-C). ICM produced low and variable ion current whereas the opposite was true for the graphitic GCI. Our optimized method produced AMS targets of graphite-coated iron powder (GCIP) 100% of the time. The GCIP shared some of the same properties as GCI in that both were black in color, both produced robust ion current consistently, their FT-IR spectra had the [sp.sup.2] bond, their Raman spectra had matching D, G, G', D+G, and D' bands, and their XRD spectra showed matching crystal size. GCIP was a powder that was easy to tamp into AMS target holders that also facilitated high throughput. We concluded that AMS targets of GCIP were a mix of graphitizable carbon and [Fe.sub.3]C crystal, because none of their spectra, FT-IR, Raman, or XRD, matched exactly those of the graphite standard. Nevertheless, AMS targets of GCIP consistently produced the strong, reliable, and reproducible ion currents for high-throughput AMS analysis (270 targets per skilled analyst/day) along with accurate and precise [F.sub.m] values.

The properties of long linear carbon clusters are investigated. A transition for long linear [C.sub.n] chains from essentially nonalternating cumulenic structures to bond length alternating acetylenic structures is observed.

A new 3D pulse sequence for NMR diffusion measurements in complex mixtures is presented. It is based on the constant-time (CT) HSQC experiment and combines diffusion delay with the carbon evolution time. This combination has great potential to obtain high resolution in the carbon dimension. When using classical sampling of the carbon dimension, maximal resolution would require a large number of time increments, leading to unrealistically long acquisition times. The application of computer-opthnized spectral aliasing allows one to reduce the number of time increments and the total acquisition time by 1-2 orders of magnitude by taking advantage of the information content of 1D carbon spectra, HSQC experiments, or both. With the new CT-HSQC-IDOSY experiment, the diffusion rates of the six anomers present in a 0.1 M [D.sub.2]O solution of glucose, maltose, and maltotriose could be obtained at natural abundance in 8 h with standard deviations below 5%.

The principles of protein design to create a peptide, denoted nano-1, that fold into an amphiphilic alpha-helix and coats carbon nanotubes are presented. Manipulating solution conditions that affect peptide-peptide interactions can control the size and morphology of the fibers.

Byline: David B. Redmond (1), Charles M. Quinn (1), Patrick W. Fowler (2) Abstract: Some new aspects of qualitative molecular-orbital theory are developed within the context of group theory and a symmetrized Huckel approximation. Conclusions concerning the eigenvalue sums for sets of eigenfunctions of the same symmetries, the occurrence of repetitions of symmetry-adapted projections and the relations between eigenvalues of I.sub.g and I.sub.u symmetries are exemplified using the .sub.120 cage structure of I.sub.h point symmetry. The implications of the orbit-by-orbit approach are outlined for larger clusters. Author Affiliation: (1) Departments of Mathematics and Chemistry, National University of Ireland, Maynooth, Co, Kildare, Ireland (2) Department of Chemistry, The University of Exeter, Stocker Road, Exeter, England, UK Article History: Registration Date: 29/09/2004

The flow-induced instability of double-walled carbon nanotubes (DWCNTs) based on Donnell's shell theory and the effects of the van der Waals (vdW) interaction on the instability are investigated. The comparison of Donnell's shell model with the Eulerian beam model has shown that Donnell's shell model has predicted more accurate results than the Eulerian beam model for DWCNTs.

A study reports on the first example of facile and clean perfluoroalkyl-aryl (C[F.sub.3]-Ar) reductive elimination from a Pd(II) complex under mild conditions. The role of Xantphos on Pd for the C[F.sub.3]-Ph bond formation is found to be critical and replacement of the Xantphos ligand on Pd with P[Ph.sub.3] or cis-chelating dppbz, dppe, dppp, and tmeda blocks the Are-C[F.sub.3] bond forming path.

The adsorption and desorption characteristics of [H.sub.2] and [D.sub.2] on porous carbons like a carbon molecular sieve (CMA T3A) are investigated. The results represent the first experimental observation of kinetic isotopes quantum molecular sieving in porous material due to the larger zero-point energy for the lighter [H.sub.2], resulting in slower adsorption/desorption kinetics compared with the heavier [D.sub.2].

Density functional theory (DFT) calculations are used to investigate C[O.sub.2] reforming of C[H.sub.4] on Ni(111). The computed energy barriers of the most favorable elementary reaction have identified the C[H.sub.4] activation into C[H.sub.3] and H as the rate-determining step of C[O.sub.2] reforming of C[H.sub.4] on Ni(111).

An isotopically enriched C homoepitaxial diamond layer of 6 plusmn 1 (mu)m thickness, grown on top of a brilliant cut diamond anyil by a microwave plasma chemical vapor deposition process for application as a pressure sensor is presented. A Calibration for the C Raman mode of this extremely thin epitaxial layer to 156 GPa using ruby fluorescence and the equation of state of copper as secondary pressure standards is provided.

The catalytic enantioselective Friedel-Crafts reactions of reactive ethenetricarboxylates and acyl-substituted methylenemalonates are investigated to study new substituents such as carboxyl and carbonyl groups. The secondary orbital interaction on approach of indole to the less hindered side of the 1-Cu(II)-ligand complex is used to explain enantioselectivity.

The investigation of the structural arrangement of the sp(super 2) phase in amorphous unhydrogenated carbon nitride (a-CN(sub x)) films and its effect on their physical properties were conducted. The analysis of these results in terms of the sp(super 2) phase in the layers, takes place when deposition was performed at higher laser intensities.

The atmospheric chemistry of (CF3)(sub 2)CHOCH3, a possible HCFC/HFC alternative, is studied with the help of a smog chamber/FT-IR technique. The troposperic lifetime of (CF3)(sub 2)CHOCH3 is estimated to be 2.0 months and the degradation mechanism of (CF3)(sub 2)CHOCH3 initiated by OH radicals is investigated using FT-IR spectroscopy at 298 K.

Structural and electrical properties of printed polymeric thin films and multilayers were designed to set up field-effect transistors. The design allowed a spacing of source and rain of 25 mum using a diluted carbon ink and polyaniline solution.

The study of contacting a connecting a carbon nanotorus (CNTR) with contacts of different degrees of transparency to shed light on the effects of the geometry and the chemistry of the contact on the transport properties of CNTR is carried out.

Controlled synthesis of the carbon nanoparticles (CNPs) comprising MW-CNTs and multishelled nanoparticles by the arc in water method is demonstrated. Results show that synthesis of CNPs by the arc in water method can be elaborately controlled.

A theoretical analysis of the operational characteristics of a carbon-nanotube-based three-terminal nanorelay is performed. It is shown that short range and van der Waals (VDW) have a significant impact on the characteristics of the relay and introduce design constraints.

Fluorinated amorphous carbon (a-C:F) films were deposited by radio frequency bias assisted microwave plasma electron cyclotron resonance chemical vapor deposition. Due to the short carrier lifetime, a pronounced blue shift of the photoluminescence spectrometer (PL) peak in a C:F film is observed.

Radical distribution functions (RLDS) characterized short range order in amorphous carbon thin films containing silicon and hydrogen (Si-ac:H). Thin film material properties were co-related to key radial distributions functions (RDF) characteristics.

Conjugate addition is a versatile reaction that allows the formation of new carbon-carbon or carbon-heteroatom bonds from a variety of acceptors and nucleophiles. The stereochemical outcome of the conjugate additions to enoates is shown to be dependent on the nature of the nucleophiles.

The results of potentiodynamic and transient potentiostatic measurements on the O2 reduction reaction (ORR) kinetics and on the CO adlayer oxidation in O2-saturated solution CO(sub ad)-covered Pt/Vulcan electrodes are described. The resulting data under fuel cell relevant conditions are presented.

The basic sorbents based on CaO are synthesized, characterized, and tested for the high capacity and selectivity for CO2 and selected gas mixtures simulating flue gas. The highly promising sorbents based on Cs/CaO, that demonstrated zero affinity for N2 and O2 and very low affinity for water, are obtained from the results.

2H and 13C NMR is used to study the orientional order and the molecular of the banana mesogen 4-chloro-1,3-phenylene bis{4,4'-(11-undecenyloxy)benzoyloxy}benzoate in its nematic phase. The comparison of (super 2)H and (super 13)C NMR helps in understanding the real structure of banana-shaped compounds in their mesophases.

The effects of sonolysis and thermal treatment conditions on chemical composition, magnetic properties, and particle size of Fe/Fe3C nanocrystalline material are investigated. It is seen that the nanocrystalline particles have a core-shell structure where a coating of Fe3C and carbon protects the body-centered cubic Fe in the core from oxidation.

The procedure to estimate the carbon-carbon bond distance in the naphthalene molecule is described. The procedure is easily performed and can be done either at home or in the classroom, with the restriction that the mass of the naphthalene must be determined using an analytical or a precise balance.

A two-minute overhead demonstration using a molecular model kit is employed for illustrating the unique binding of cyclopropane. It is reported that most model kits, much like an sp(super 3) hybridized carbon atom, resist forming 60-degree bond angles.

The coordination and haptotropic rearrangement of the Cr(CO)3 fragment on the (6,0) carbon nanotube sidewalls is investigated by the static and dynamic density functional theory calculations. An ab initio molecular dynamics simulations has been carried out to characterize the dynamics of the haptotropic rearrangement of Cr(CO)3 on the carbon nanotube sidewalls with the help of the Car-Parrinello (CP) method.

The spectral characterization of Pt supported on Al2O3, CeO2, and mixed CeO2-Al2O3 oxides with different CeO2 loadings shows the great influence of the type of the support and pretreatment temperature on the surface state of Pt and Ce. The results obtained by applying the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy of CO adsorption to the samples is presented.

The actuation mechanism of an electrochemical actuator was understood and associated parameters were determined by investigating the charge transfer dynamics on the surface of single-wall carbon nanotube sheets using in situ Raman spectroscopy. The impact of these findings on the suitability of such material for use in electrochemical devices such as actuators is emphasized.

The inert atmosphere composition in electric-arc discharge process was varied to control the temperature inside the production chamber, thereby affecting the diameter distribution of the nanotubes. It was also observed that the nanotube production rate and the size of bundles decrease with an increase of the argon percentage.

The generation of small Ni particles by the fragmentation of Ni tips during the growth process of vertically aligned carbon nanotubes at 500 degrees Celsius is reported. A phenomenological model for the secondary growth of carbon nanotubules is proposed.

An investigation was carried out on the diffusion of Cs in multiwalled carbon nanotubes (MWNTs) by probing the lateral distribution of Cs along the axes on the nanotubes following Cs deposition on the tips of aligned MWNTs, using photoelectron spectromicroscopy. The value of 2 x 10(super -12) cm (super 2)/s obtained is seven orders of magnitude smaller than that in graphite, although the local atomic structure of an intercalated MWNT is very similar to that of the intercalated graphite.

A method to prepare a well-ordered Co nanowire array, without contamination, on an anodic aluminum oxide (AAO) template, and the field emission properties of aligned carbon nanotubes (CNTs) fabricated by disproportionation of CO on the well-ordered Co nanowire array is reported. The report revealed that the electron field emission turned on at a field as low as 1.1 V/mu m and the enhancement factor was 3520 by assuming a CNT work function of 5 eV.

The field emission properties of thick films of carbon nanohorns are reported. The films show good field emission characteristics, a low turn-on field and good long-term stability due to the sharp horn-like structures.

A study was conducted to examine the growth mechanism of carbon nanocoils (CNC) to find out the effects of the catalyst constitution and the chemical vapor deposition (CVD) conditions. The result shows that the coils grow mainly from the interface of iron and indium tin oxide films.

A study was conducted, under normal gravity (1 G) and nongravity (0 G) conditions, to numerically investigate the dispersion process of typical carbon cluster synthesized by gas evaporation using dc arc, to clarify the effect of natural convection. The result reveals significant effects of natural convection on the cooling process of a carbon cluster in gas evaporation using dc arc.