@article {2556, title = {An Accurate Equation of State for Fluids and Solids}, journal = {Journal of Physical Chemistry B}, volume = {113}, number = {35}, year = {2009}, note = {ISI Document Delivery No.: 487EETimes Cited: 0Cited Reference Count: 52Parsafar, G. A. Spohr, H. V. Patey, G. N.}, month = {Sep}, pages = {11977-11987}, type = {Article}, abstract = {A simple functional form for a general equation of state based on an effective near-neighbor pair interaction of an extended Lennard-Jones (12,6,3) type is given and tested against experimental data for a wide variety of fluids and solids, Computer simulation results for ionic liquids are used for further evaluation. For fluids, there appears to be no upper density limitation on the equation of state, The lower density limit for isotherms near the critical temperature is the critical density. The equation of state gives a good description of all types of fluids, nonpolar (including long-chain hydrocarbons), polar, hydrogen-bonded, and metallic, at temperatures ranging from the triple point to the highest temperature for which there is experimental data. For solids, the equation of state is very accurate for all types considered, including covalent, molecular, metallic, and ionic systems. The experimental pvT data available for solids does not reveal any pressure or temperature limitations. An analysis of the importance and possible underlying physical significance of the terms in the equation of state is given.}, keywords = {400 DEGREES C, COMPRESSED LIQUIDS, DENSE FLUIDS, HIGH-PRESSURES, linear isotherm regularity, PVT PROPERTIES, SODIUM-CHLORIDE, TEMPERATURE, THERMODYNAMIC PROPERTIES, UNIVERSAL EQUATION}, isbn = {1520-6106}, url = {://000269252700022}, author = {Parsafar, G. A. and Spohr, H. V. and Patey, G. N.} } @article {2474, title = {Spectrum of Excess Partial Molar Absorptivity. I. Near Infrared Spectroscopic Study of Aqueous Acetonitrile and Acetone}, journal = {Journal of Physical Chemistry B}, volume = {113}, number = {35}, year = {2009}, note = {ISI Document Delivery No.: 487EETimes Cited: 4Cited Reference Count: 22Koga, Yoshikata Sebe, Fumie Minami, Takamasa Otake, Keiko Saitow, Ken-ichi Nishikawa, Keiko}, month = {Sep}, pages = {11928-11935}, type = {Article}, abstract = {We study the mixing schemes or the molecular processes occurring in aqueous acetonitrile (ACN) and acetone (ACT) by near-infrared spectroscopy (NIR). Both solutions (any other aqueous solutions) are not free from strong and complex intermolecular interactions. To tackle such a many-body problem, we first use the concept of the excess molar absorptivity, epsilon(E), which is a function of solute mole fraction in addition to that of wavenumber, nu. The plots of F E calculated from NIR spectra for both aqueous solutions against nu showed two clearly separated bands at 5020 and 5230 cm(-1); the former showed negative and the latter positive peaks. At zero and unity mole fractions of solute, epsilon(E) is identically zero independent of v. Similar to the thermodynamic excess functions, both negative and positive bands grow in size from zero to the minimum (or the maximum) and back to zero, as the mole fraction varies from 0 to 1. Since the negative band{\textquoteright}s nu-locus coincides with the NIR spectrum of ice, and the positive with that of liquid H2O, we suggest that on addition of solute the "ice-likeness" decreases and the "liquid-likeness" increases, reminiscent of the two-mixture model for liquid H2O. The modes of these variations, however, are qualitatively different between ACN-H2O and ACT-H2O. The former ACN is known to,let as a hydrophobe and ACT as a hydrophile from Our previous thermodynamic studies. To see the difference more clearly, we introduced and calculated the excess partial molar absorptivity of ACN and ACT, epsilon(E)(N), and epsilon(E,)(T) respectively. The mole fraction dependences of epsilon(E)(N) and epsilon(E)(T) show qualitatively different behavior and are consistent with the detailed mixing schemes elucidated by our earlier differential thermodynamic studies. Furthermore, we found in the H2O-rich region that the effect of hydrophobic ACN is acted on the negative band at 5020 cm(-1), while that of hydrophilic ACT is on the positive high-energy band. Thus, the present method of analysis adds more detailed insight into the difference between a hydrophobe and a hydrophile in their effects on H2O.}, keywords = {2-DIMENSIONAL CORRELATION SPECTROSCOPY, 25-DEGREES-C, CHEMICAL-POTENTIALS, ENTHALPIES, ENTROPIES, HYDROGEN-BONDS, MIXTURES, NON-ELECTROLYTES, TEMPERATURE, WATER}, isbn = {1520-6106}, url = {://000269252700016}, author = {Koga,Yoshikata and Sebe, F. and Minami, T. and Otake, K. and Saitow, K. and Nishikawa, K.} } @article {2620, title = {Structural and dynamical properties of ionic liquids: The influence of charge location}, journal = {Journal of Chemical Physics}, volume = {130}, number = {10}, year = {2009}, note = {ISI Document Delivery No.: 420IFTimes Cited: 8Cited Reference Count: 31Spohr, H. V. Patey, G. N.}, month = {Mar}, pages = {11}, type = {Article}, abstract = {The properties of ionic liquids depend on the chemical structure of the constituent ions. An important difference between molten inorganic salts and room temperature ionic liquids (RTILs) is that in RTILs the charge is frequently not located at the center of mass. This paper describes a molecular dynamics investigation of the influence of charge location on the structure and transport properties of ionic liquids. The model considered consists of univalent spherical ions with the cation charge moved away from its center of mass. It is shown that the charge location has an important influence on the liquid properties. As the charge is moved off center, the electrical conductivity initially increases, and the shear viscosity decreases. However, when the charge exceeds a certain displacement, this behavior is reversed. With further charge displacement, the conductivity decreases sharply and the viscosity increases rapidly. This behavior reversal can be traced to the formation of directional ion pairs that are present in sufficient numbers, and have lifetimes sufficiently long to strongly influence the liquid properties. We suggest that the influence of directional ion pairing can explain what appear to be anomalously low conductivities and high viscosities observed for some RTILs. The rotational and reorientational motions of the cations are examined, and shown to be strongly influenced by ion-pair formation when the charge is far off center. The temperature dependence of the transport properties is considered for selected systems, and deviations from Arrhenius behavior are found to be most important for the conductivity. Based on our results, this possibly indicates that directional ion pairs create an additional "barrier" to charge transport in some ionic liquids.}, keywords = {ANION, DIFFUSION, electrical conductivity, HYDROGEN-BONDS, liquid metals, liquid structure, liquid theory, molecular dynamics method, MOLECULAR-DYNAMICS, PHYSICOCHEMICAL PROPERTIES, pressure, TEMPERATURE, TRANSPORT-PROPERTIES, VISCOSITIES, VISCOSITY}, isbn = {0021-9606}, url = {://000264281800024}, author = {Spohr, H. V. and Patey, G. N.} } @article {2539, title = {Very slow expansion of an ultracold plasma formed in a seeded supersonic molecular beam of NO}, journal = {Physical Review A}, volume = {79}, number = {6}, year = {2009}, note = {ISI Document Delivery No.: 466XZTimes Cited: 2Cited Reference Count: 35Morrison, J. P. Rennick, C. J. Grant, E. R.}, month = {Jun}, pages = {7}, type = {Article}, abstract = {The double-resonant laser excitation of nitric oxide, cooled to 1 K in a seeded supersonic molecular beam, yields a gas of approximate to 10(12) molecules per cubic centimeter in a single selected Rydberg state. This population evolves to produce prompt free electrons, and a durable cold plasma of electrons and intact NO+ ions. This plasma travels with the molecular beam through a field-free region to encounter a grid. The atomic weight of the expansion gas controls the beam velocity and hence the flight time from the interaction region to the grid. Monitoring electron production as the plasma traverses this grid measures its longitudinal width as a function of flight time. Comparing these widths to the width of the laser beam that defines the initial size of the illuminated volume allows us to gauge the rate of expansion of the plasma. We find that the plasma created from the evolution of a Rydberg gas of NO expands at a small but measurable rate, and that this rate of expansion accords with the Vlasov equations for an initial electron temperature of T-e approximate to 7 K.}, keywords = {3-BODY RECOMBINATION, COMPOUNDS, ELECTRONS, GASES, laser cooling, molecular beams, molecule-photon collisions, NEUTRAL PLASMAS, NITROGEN, Photoexcitation, PLASMA, plasma collision processes, positive ions, RATES, RYDBERG ATOMS, Rydberg states, STATES, TEMPERATURE, TEMPERATURES, VACUUM, Vlasov equation}, isbn = {1050-2947}, url = {://000267700100086}, author = {Morrison, J. P. and Rennick, C. J. and Grant, E. R.} } @article {2342, title = {A novel functional polymer with tunable LCST}, journal = {Macromolecules}, volume = {41}, number = {14}, year = {2008}, note = {ISI Document Delivery No.: 326NJTimes Cited: 13Cited Reference Count: 44Zou, Yuquan Brooks, Donald E. Kizhakkedathu, Jayachandran N.}, month = {Jul}, pages = {5393-5405}, type = {Article}, abstract = {Poly(N-[(2,2-dimethyl-1,3-dioxolane)methyl]acrylamide) (PDMDOMA), a novel thermo-responsive polymer containing pendant dioxolane groups was synthesized via atom transfer radical polymerization (ATRP). Water soluble PDMDOMAs with controlled molecular weight and narrow molecular weight distribution were obtained. GPC-MALLS and MALDI-TOF-MS analysis verified the controlled nature of polymerization. It was found that an aqueous solution of PDMDOMA has a lower critical solution temperature (LCST) around 23 degrees C. The LCST of PDMDOMA was finely tuned over a wide temperature range by the partial hydrolysis of the acid labile dioxolane side group to form diol moieties (PDMDOMA diols). Unlike the traditional way of controlling LCST by copolymerization, the advantage of this method is that a series of thermo-responsive polymers with different LCST can be prepared from a single batch of polymer with comparable molecular weight profiles. The LCST of the resulting PDMDOMA diols increased almost linearly up to 28 mol \% of diol in the copolymer and the LCST disappeared above 43 mol \% diol content. The diol moiety generated during the hydrolysis was further oxidized to create aldehyde functionalities along the polymer backbone (PDMDOMA-aldehyde). The NMR analysis indicates that the aldehyde groups in the polymer exist in equilibrium with their covalent hydrates in water. The presence and reactivity of aldehyde groups on the PDMDOMA-aldehyde was verified by reaction with propylamine and aniline. The LCST of PDMDOMA-aldehyde did not change significantly compared to the precursor diol polymer. However, the propylamine or aniline derivatives showed a dramatic decrease in the LSCT possibly due to an increase in the hydrophobic character. The LCST of PDMDOMA-propylamine and PDMDOMA-aniline derivatives depends on the composition and nature of the attached groups. The structure of PDMDOMA and its derivatives were fully characterized by H-1, C-13, and 2D HMQC NMR, GPC-MALLS, and MALDI-TOF-MS.}, keywords = {2-(2-METHOXYETHOXY)ETHYL METHACRYLATE, AQUEOUS-SOLUTIONS, N-ISOPROPYLACRYLAMIDE, OLIGO(ETHYLENE GLYCOL) METHACRYLATE, POLYMERS, PROTEINS, SMART, SOLID TUMORS, STIMULI-RESPONSIVE POLYMERS, TEMPERATURE, TRANSFER RADICAL POLYMERIZATION}, isbn = {0024-9297}, url = {://000257665900045}, author = {Zou, Y. Q. and Brooks, D. E. and Kizhakkedathu, J. N.} } @article {1601, title = {A pentagonal pyramidal zirconium imido complex for catalytic hydroamination of unactivated alkenes}, journal = {Organometallics}, volume = {25}, number = {17}, year = {2006}, note = {ISI Document Delivery No.: 070PZTimes Cited: 66Cited Reference Count: 40Thomson, Robert K. Bexrud, Jason A. Schafer, Laurel L.}, month = {Aug}, pages = {4069-4071}, type = {Article}, abstract = {The first, isolable group 4 imido complexes capable of promoting intramolecular olefin hydroamination for the preparation of N-containing heterocycles are presented. The structurally characterized 6-coordinate bis(amidate)-supported zirconium imido complex is a rare example of distorted-pentagonal-pyramidal geometry.}, keywords = {ALKYNE HYDROAMINATION, allenes, AMIDATE COMPLEXES, BIS(AMIDATE) TITANIUM PRECATALYST, C-H ACTIVATION, HYDROAMINATION, INTERMOLECULAR HYDROAMINATION, INTRAMOLECULAR, REACTIVITY, TEMPERATURE, TI(NME2)(4)}, isbn = {0276-7333}, url = {://000239536800007}, author = {Thomson, R. K. and Bexrud, J. A. and Schafer, L. L.} } @article {984, title = {Coulomb collisional processes in space plasmas; relaxation of suprathermal particle distributions}, journal = {Planetary and Space Science}, volume = {52}, number = {10}, year = {2004}, note = {ISI Document Delivery No.: 858UKTimes Cited: 4Cited Reference Count: 38}, month = {Aug}, pages = {923-933}, type = {Article}, abstract = {Nonequilibrium distributions of space plasmas are often characterized by extended high-energy tails. This paper provides a detailed analysis of the relaxation of such isotropic nonequilibrium plasmas. We consider an energetic charged species dilutely dispersed in a fully ionized plasma, which acts as a heat bath at equilibrium. The minor constituent is referred to as a "test particle" and collisions between test particles are not included. We study the approach to equilibrium with a finite difference method of solution of the Fokker-Planck equation appropriate for collisions between charged particles. The solution of the Fokker-Planck equation is also presented formally as an expansion in the eigenfunctions of the Fokker-Planck operator. The main objective of the paper is the calculation of the energy-dependent relaxation times of the distribution function. A strong energy dependence for these relaxation times is anticipated since, for Coulomb collisions, the Rutherford cross-section varies with relative speed g as g(-4). Analogous results for neutral species are presented for comparison in the following paper. (C) 2004 Elsevier Ltd. All rights reserved.}, keywords = {ELECTRON VELOCITY DISTRIBUTION, equations, GAS, H+, KINETIC-MODEL, NUMERICAL-METHODS, POLAR WIND, relaxation, SOLAR-WIND, TEMPERATURE, TRANSITION}, isbn = {0032-0633}, url = {://000224217300004}, author = {Shizgal, B. D.} } @article {910, title = {Synthesis of well-defined environmentally responsive polymer brushes by aqueous ATRP}, journal = {Macromolecules}, volume = {37}, number = {3}, year = {2004}, note = {ISI Document Delivery No.: 771TWTimes Cited: 102Cited Reference Count: 56}, month = {Feb}, pages = {734-743}, type = {Article}, abstract = {Functionalized anionic polystyrene latex particles with ATRP initiators were synthesized by surfactant-free shell-growth emulsion polymerization of styrene and 2-(2{\textquoteright}-chloropropionato)ethyl acrylate (HEA-Cl). N-Isopropylacrylamide (NIPAM) was polymerized from these particles by surface-initiated aqueous ATRP using PMDETA/CuCl and HMTETA/CuCl catalysts to synthesize poly(N-isopropylacrylamide) (PNIPAM) brushes. The grafted latexes were characterized for molecular weight of the PNIPAM chains, grafting density, and hydrodynamic thickness of the grafted polymer layer. Molecular weights of the grafted PNIPAM chains depended on the monomer concentration, concentration of copper(II) complex, and the presence of external initiator in the reaction medium. M-n of the grafted chains increases with increase in the monomer concentration and decreases with addition of copper(II) complex and external initiator. The HMTETA/CuCl catalyst produces higher molecular weight chains than PMDETA/CuCl. Molecular weights from similar to50 000 to 800 000 with low polydispersities, between 1.25 and 1.4, were achieved. The grafting density of PNIPAM on the surface increases with increasing monomer concentration and decreases with addition of copper(II) catalyst and external initiator. Block copolymerization of N,N-dimethylacrylamide from PNIPAM-grafted latex demonstrated that the chains are terminated with a chlorine atom, and the grafting reactions are taking place by the ATRP mechanism. The hydrodynamic thickness (HT) of the grafted PNIPAM layer scales as DP0.66 (where DP = degree of polymerization) at constant grafting density (chains/nm(2)). The HT values for PNIPAM brushes are sensitive to temperature and salt concentration. Since the transition from extended coil to collapsed structure occurs over a range of temperature and salt concentration, it follows a second-order transition, as predicted by theory. The thickness of the collapsed brush is sensitive to the type of stimulus used to induce the phase transition.}, keywords = {GLOBULE TYPE TRANSITIONS, INTERFACES, N-DIMETHYLACRYLAMIDE) BRUSHES, PARTICLES, POLY(N, POLY(N-ISOPROPYLACRYLAMIDE), PROTEIN, SILICA, SURFACE-INITIATED POLYMERIZATIONS, TEMPERATURE, TRANSFER RADICAL POLYMERIZATION}, isbn = {0024-9297}, url = {://000188803000010}, author = {Kizhakkedathu, J. N. and Norris-Jones, R. and Brooks, D. E.} } @article {5190, title = {Ion fragmentation in an electrospray ionization mass spectrometer interface with different gases}, journal = {Rapid Communications in Mass Spectrometry}, volume = {15}, number = {4}, year = {2001}, note = {ISI Document Delivery No.: 405PTTimes Cited: 12Cited Reference Count: 43}, pages = {249-257}, type = {Article}, abstract = {Nitrogen, argon, and krypton are used as curtain gases in an electrospray ionization mass spectrometer in an attempt to study the effect of these gases on the extent of ion fragmentation between the orifice and the skimmer of the interface region. A previously published collision model predicts that the degree of ion fragmentation increases with increasing mass of the curtain gas. However, the fragmentation yields are found to be the opposite to that expected. It is believed that the reversed trend with argon and krypton is caused by condensation of the gases within the free jet expansion between the orifice and the skimmer. A condensation parameter can be used to predict the degree of clustering of gases within a free jet expansion. When the condensation parameter is minimized, the predicted trend of fragmentation with mass is observed. Copyright (C) 2001 John Wiley \& Sons, Ltd.}, keywords = {CONDENSATION, FREE-JET EXPANSIONS, INDUCED DISSOCIATION, LIQUID-HELIUM CLUSTERS, MYOGLOBIN, PERFORMANCE, PROTEIN IDENTIFICATION, SPECTROSCOPY, TECHNOLOGY, TEMPERATURE}, isbn = {0951-4198}, url = {://000167168800002}, author = {Schneider, B. S. and Douglas, D. J. and Chan, D. D. Y.} } @article {4885, title = {Prediction of the thermal conductivity of gases based on the Rainwater-Friend theory and a new corresponding states function}, journal = {Physica a-Statistical Mechanics and Its Applications}, volume = {275}, number = {1-2}, year = {2000}, note = {ISI Document Delivery No.: 270GXTimes Cited: 14Cited Reference Count: 52}, month = {Jan}, pages = {48-69}, type = {Article}, abstract = {The Rainwater-Friend theory is used for the evaluation of the initial density dependence of the thermal conductivity of the noble gases using accurate realistic potentials. This theory, which was originally developed for spherically symmetric potentials, is adapted for the calculation of the initial density dependence of the translational contribution of the thermal conductivity of polyatomic gases. The internal state contribution is evaluated using a combination of Mason-Monchick theory and hard-sphere Enskog theory. At high density, beyond the range of the Rainwater-Friend theory, a deviation thermal conductivity function has been presented. With the help of this function, an easily usable corresponding-states function for the calculation of the thermal conductivity of supercritical gases has been developed, which is valid over a wide temperature range and for pressures up to 400 MPa. (C) 2000 Elsevier Science B.V. All rights reserved.}, keywords = {ARGON, CARBON-DIOXIDE, high-pressure thermal conductivity, INITIAL DENSITY-DEPENDENCE, NOBLE-GASES, PHYSICAL-PROPERTIES, POLYATOMIC GASES, POTENTIAL-ENERGY CURVE, Rainwater-Friend theory, second, TEMPERATURE, thermal conductivity, thermal conductivity virial coefficient, TRANSPORT-PROPERTIES, ZERO DENSITY}, isbn = {0378-4371}, url = {://000084528200005}, author = {Najafi, B. and Araghi, R. and Rainwater, J. C. and Alavi, S. and Snider, R. F.} } @article {4861, title = {Speciation of key arsenic metabolic intermediates in human urine}, journal = {Analytical Chemistry}, volume = {72}, number = {21}, year = {2000}, note = {ISI Document Delivery No.: 369XXTimes Cited: 187Cited Reference Count: 45}, month = {Nov}, pages = {5172-5177}, type = {Article}, abstract = {Biomethylation is the major human metabolic pathway for inorganic arsenic, and the speciation of arsenic metabolites is essential to a better understanding of arsenic metabolism and health effects. Here we describe a technique for the speciation of arsenic in human urine and demonstrate its application to the discovery of key arsenic metabolic intermediates, monomethylarsonous acid (MMA(III)) and dimethylarsinous acid (DMA(III)), in human urine. The study provides a direct evidence in support of the proposed arsenic methylation pathway in the human. The finding of MMA(III) and DMA(III) in human urine, along with recent studies showing the high toxicity of these arsenicals, suggests that the usual belief of arsenic detoxification by methylation needs to be reconsidered, The arsenic speciation technique is based on ion pair chromatographic separation of arsenic species on a 3-mum particle size column at 50 degreesC followed by hydride generation atomic fluorescence detection. Speciation of MMA(III), DMA(III), arsenite (As-III), arsenate (As-V), monomethylarsonic acid(MMA(V)), and dimethylarsinic acid (DMA(V)) in urine samples is complete in 6 min with detection limits of 0.5-2 mug/L. There is no need for any sample pretreatment. The capability of rapid analysis of trace levels of arsenic species, which resulted in the findings of the key metabolic intermediates, makes the technique useful for routine arsenic speciation analysis required for toxicological and epidemiological studies.}, keywords = {ATOMIC FLUORESCENCE DETECTION, BLACKFOOT DISEASE, DRINKING-WATER, EXCRETION, EXPOSURE, INGESTION, METHYLATION, PERFORMANCE LIQUID-CHROMATOGRAPHY, SEPARATION, TEMPERATURE}, isbn = {0003-2700}, url = {://000165094000012}, author = {Le, X. C. and Lu, X. F. and Ma, M. S. and Cullen, W. R. and Aposhian, H. V. and Zheng, B. S.} } @article {4364, title = {Improved initial density dependence of the viscosity and a corresponding states function for high pressures}, journal = {Physica a-Statistical Mechanics and Its Applications}, volume = {260}, number = {1-2}, year = {1998}, note = {ISI Document Delivery No.: 135WLTimes Cited: 24Cited Reference Count: 50}, month = {Nov}, pages = {31-48}, type = {Article}, abstract = {The initial density correction to gaseous viscosity using accurate realistic potentials of the noble gases is evaluated using the Rainwater-Friend theory. It is shown that this theory works satisfactorily for densities up to about 2 mol dm(-3). Due to the superimposability of the noble gas potential functions, a universal function of the reduced second viscosity virial coefficient is obtained over the entire reduced temperature range. At densities beyond the range of the theory, a variant of the excess viscosity is developed, by which the viscosity of the different gases can be easily calculated above the critical temperature for pressures up to 900 MPa. The accuracy of this method is within the experimental uncertainties. (C) 1998 Elsevier Science B.V. All rights reserved.}, keywords = {11 POLYATOMIC GASES, ARGON, COEFFICIENT, COEFFICIENTS, EQUILIBRIUM, high-pressure excess viscosity, NOBLE-GASES, ORGANIC VAPORS, PHYSICAL-PROPERTIES, Rainwater-Friend theory, second viscosity virial, TEMPERATURE, THERMAL-CONDUCTIVITY, TRANSPORT-PROPERTIES, VISCOSITY}, isbn = {0378-4371}, url = {://000076825600004}, author = {Najafi, B. and Ghayeb, Y. and Rainwater, J. C. and Alavi, S. and Snider, R. F.} } @article {3847, title = {Characteristics of an inductively coupled argon plasma operating with organic aerosols .3. Radial spatial profiles of solvent and analyte species}, journal = {Journal of Analytical Atomic Spectrometry}, volume = {11}, number = {1}, year = {1996}, note = {ISI Document Delivery No.: TR267Times Cited: 11Cited Reference Count: 28}, month = {Jan}, pages = {43-52}, type = {Article}, abstract = {The effect of organic solvent load on the radial emission profiles for Mg I, Mg a C I, C-2, and CN was measured. The three dimensional information reveals the observation zones where the emission intensity of these species is proportional to solvent load and plasma excitation conditions.}, keywords = {ATOMIC EMISSION-SPECTROMETRY, EXCITATION, INDUCTIVELY COUPLED ARGON PLASMA, INTENSITY RATIOS, ORGANIC SOLVENT, radial spatial profiles, SOLVENT PLASMA LOAD, TEMPERATURE}, isbn = {0267-9477}, url = {://A1996TR26700006}, author = {Weir, D. G. and Blades, M. W.} } @article {3743, title = {Monitoring of the formation and removal of bulk, surface, and interfacial carrier traps on silicon(100)}, journal = {Canadian Journal of Physics}, volume = {74}, year = {1996}, note = {ISI Document Delivery No.: WU206Times Cited: 8Cited Reference Count: 177th Canadian Semiconductor Technology ConferenceAUG 14-18, 1995OTTAWA, CANADANatl Res Council CanadaSuppl. 1}, pages = {S233-S238}, type = {Proceedings Paper}, abstract = {An RF probe was used to monitor the steady-state photo-generated carrier concentration in silicon with and without an oxide layer. The changes in this steady-state concentration during exposure to gaseous molecular and atomic species such as He, H-2, O-2, H, and O at temperatures between 25 and 450 degrees C are interpreted in terms of changes in the bulk silicon, interface, and exposed surface. The initial experiments established the relationship between the carrier concentration and the RF-probe signal, and distinguished between changes in the bulk, and on silicon surfaces and interfaces. It was found that in the case of hydrogen, bulk passivation and depassivation by H-2 can be observed only at elevated temperatures, with or without an oxide layer. H-atom depassivation can be observed at all temperatures and is irreversible at room temperature. The formation of an oxide layer by exposure to O atoms at 25 and 450 degrees C was followed, and the oxides formed were then treated in an attempt to create an SiO2/Si interface with an acceptable density of interfacial states.}, keywords = {111 SI-SIO2 INTERFACE, ATOMIC-HYDROGEN, H-2, KINETICS, PASSIVATION, PB CENTERS, SI/SIO2 INTERFACE, STATES, TEMPERATURE}, isbn = {0008-4204}, url = {://A1996WU20600047}, author = {Li, H. J. and Ogryzlo, E. A.} } @article {3812, title = {Vibrational nonequilibrium in a supersonic expansion with reaction: Application to O-2-O}, journal = {Journal of Chemical Physics}, volume = {104}, number = {10}, year = {1996}, note = {ISI Document Delivery No.: TX780Times Cited: 27Cited Reference Count: 127}, month = {Mar}, pages = {3579-3597}, type = {Review}, abstract = {The hypersonic expansion of O-2 through a nozzle is considered. The steady nonequilibrium vibrational distribution function of O-2, and the nonequilibrium forward reaction rate coefficient for the dissociation of O-2 are calculated theoretically. In the first instance, the vibrational relaxation of O-2 in the absence of reaction is examined in the temperature range 500-2500 K. The master equation for the vibrational populations, coupled to the steady one-dimensional conservation equations is solved numerically. The vibrational population obtained in this way, is compared to the distribution calculated using either a Treanor model or a Boltzmann distribution characterized by a vibrational temperature. The transition probabilities between O-2 vibrational levels employed take into account the vibrational anharmonicity, and the anisotropic intermolecular potential. For the temperature range 2500-5000 K, the vibrational relaxation including dissociation and recombination is studied. The reactive probabilities that are required for this calculation were obtained from the model of Kiefer and Hajduk [Chem. Phys. 38, 329 (1979)]. (C) 1996 American Institute of Physics.}, keywords = {CHEMICAL-KINETICS, CROSS-SECTIONS, DIATOMIC, DISSOCIATION, HF-HF COLLISIONS, OSCILLATOR, POTENTIAL-ENERGY SURFACE, RATE CONSTANTS, SELF-RELAXATION, STATE, TEMPERATURE}, isbn = {0021-9606}, url = {://A1996TX78000021}, author = {Shizgal, B. D. and Lordet, F.} } @article {3449, title = {ELECTROSTATIC EFFECTS ON THE ADSORPTION AND CARBODIIMIDE-MEDIATED COUPLING OF FERRICHROME-A TO AMINE-MODIFIED SILICA}, journal = {Journal of Colloid and Interface Science}, volume = {174}, number = {2}, year = {1995}, note = {ISI Document Delivery No.: RV175Times Cited: 2Cited Reference Count: 26}, month = {Sep}, pages = {480-489}, type = {Article}, abstract = {The adsorption behavior and carbodiimide-mediated coupling were examined for a carboxyl-containing cyclic hexapeptide, ferrichrome A (FeA), on amine-modified silica beads. Adsorption decreased with increasing salt concentration and no adsorption was observed in 100 mM sodium chloride. Ferrichrome A in water adsorbs to amine-modified silica beads to a maximum surface concentration of 1.69 mg/m(2), corresponding to an area per molecule of 104 Angstrom(2); this adsorption is fully reversed by addition of salt. Carboxyl groups on the FeA were coupled to amine groups on silane-modified silica using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) to promote formation of a peptide bond. Ferrichrome A coupled in this way to the silica beads is not washed off in high salt. The isotherms of FeA coupled irreversibly to the beads as a function of solution concentration of FeA were measured using a constant EDC:FeA mole ratio of 50:1 and a constant EDC concentration of 20 mM. There were significant differences between the coupling and adsorption isotherms, particularly at low solution concentrations of FeA. Electrophoretic mobility measurements of the silica beads to which varying amounts of FeA had been covalently bound showed the surface was positively charged at all peptide surface concentrations. The results are consistent with a model of the surface in which FeA is coupled to a porous layer of oligomeric aminosilane through a reaction which is strongly influenced by electrostatic interactions between the surface and reagents. (C) 1995 Academic Press, Inc.}, keywords = {BINDING, TEMPERATURE}, isbn = {0021-9797}, url = {://A1995RV17500024}, author = {Melzak, K. A. and Janzen, J. and Brooks, D. E.} } @inbook {3448, title = {Modification of silica with a covalently attached antigen for use in immunosorbent assays}, booktitle = {Proteins at Interfaces Ii - Fundamentals and Applications}, series = {Acs Symposium Series}, volume = {602}, year = {1995}, note = {ISI Document Delivery No.: BE38NTimes Cited: 2Cited Reference Count: 35Proceedings PaperSymposium on Proteins at Interfaces II - Fundamentals and Applications, at the 207th National Meeting of the American-Chemical-SocietyMAR 13-17, 1994SAN DIEGO, CAAmer Chem Soc, Div Colloid \& Surface Sci1155 SIXTEENTH ST NW, WASHINGTON, DC 20036}, pages = {420-433}, publisher = {Amer Chemical Soc}, organization = {Amer Chemical Soc}, address = {Washington}, abstract = {This paper describes the preparation and characterization of a silica surface with a covalently coupled antigen, and gives an example of the use of the modified silica in immunosorbent assays. Silica beads and slides were cleaned with chromic acid and modified with 3-aminopropyltriethoxysilane. The carboxyl groups of a cyclic hexapeptide antigen, ferrichrome A, were coupled to the amine-modified silica using 1-ethyl,3,3-dimethylaminopropyl cabodiimide to promote formation of a peptide bond. Modified slides and beads were characterized with a combination of X-ray photoelectron spectroscopy and particle electrophoresis measurements, with the amount of ferrichrome A adsorbed of coupled to the beads being determined by solution depletion measurements.}, keywords = {TEMPERATURE, XPS}, isbn = {0097-61560-8412-3304-7}, url = {://A1995BE38N00030}, author = {Melzak, K. A. and Brooks, D. E.}, editor = {Horbett, T. A. and Brash, J. L.} } @inbook {3334, title = {One and two-dimensional solid-state NMR investigations of the three-dimensional structures of zeolite-organic sorbate complexes}, booktitle = {Zeolites: A Refined Tool for Designing Catalytic Sites}, series = {Studies in Surface Science and Catalysis}, volume = {97}, year = {1995}, note = {ISI Document Delivery No.: BE46VTimes Cited: 2Cited Reference Count: 25Proceedings PaperInternational Zeolite SymposiumOCT 15-20, 1995QUEBEC CITY, CANADASARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, pages = {1-10}, publisher = {Elsevier Science Publ B V}, organization = {Elsevier Science Publ B V}, address = {Amsterdam}, keywords = {3-DIMENSIONAL BONDING CONNECTIVITIES, FORM, LATTICE, NATURAL-ABUNDANCE, PARA-XYLENE, TEMPERATURE, ZSM-5}, isbn = {0-444-82130-9}, url = {://A1995BE46V00001}, author = {Fyfe, C. A. and Grondey, H. and Diaz, A. C. and Kokotailo, G. T. and Feng, Y. and Huang, Y. and Wongmoon, K. C. and Mueller, K. T. and Strobl, H. and Lewis, A. R.}, editor = {Bonneviot, L. and Kaliaguine, S.} } @article {2908, title = {THE EQUILIBRIUM PAIR DISTRIBUTION FUNCTION OF A GAS - ASPECTS ASSOCIATED WITH THE PRESENCE OF BOUND-STATES}, journal = {Journal of Chemical Physics}, volume = {99}, number = {11}, year = {1993}, note = {ISI Document Delivery No.: MJ902Times Cited: 1Cited Reference Count: 36}, month = {Dec}, pages = {9111-9121}, type = {Article}, abstract = {At thermal equilibrium the momentum distribution of atoms in a gas is usually assumed to be Maxwellian, whether classically or quantally. However, if an atom is bound in a diatomic molecule, the atom{\textquoteright}s momentum distribution is non-Maxwellian. This paper explores the consequent singlet and pair particle distribution functions in a gas having both unbound atoms and bound pairs of atoms. Comment is made on the range of behavior associated with whether the chemical equilibrium constant for diatom formation is small or large. Calculations of distribution functions and their moments for atoms which are members of dimers are presented for some specific model potentials.}, keywords = {2ND, DIMER, formation, INITIAL DENSITY DEPENDENCE, KINETIC-THEORY, PHASE-SPACE SUBDIVISION, POTENTIALS, TEMPERATURE, THERMAL-CONDUCTIVITY, TRANSPORT-PROPERTIES, VIRIAL-COEFFICIENT, VISCOSITY}, isbn = {0021-9606}, url = {://A1993MJ90200074}, author = {Rainwater, J. C. and Snider, R. F.} } @article {7259, title = {TEMPORAL EMISSION AND ABSORPTION CHARACTERISTICS OF SILVER, LEAD AND MANGANESE IN FURNACE ATOMIZATION PLASMA EXCITATION SPECTROMETRY}, journal = {Journal of Analytical Atomic Spectrometry}, volume = {7}, number = {7}, year = {1992}, note = {ISI Document Delivery No.: JY532Times Cited: 15Cited Reference Count: 37}, month = {Oct}, pages = {1039-1046}, type = {Article}, abstract = {The temporal behaviour of the signal measured for Ag, Pb and Mn in furnace atomization plasma excitation spectrometry was studied using atomic emission and atomic absorption spectrometry. Analyte was deposited both on the wall and on the r.f. electrode with and without the r.f. power applied. Analyte condensation on the r.f. electrode is observed when no plasma is formed. When the plasma is formed inside the furnace it heats the electrode such that, for Ag and Pb, condensation is not observed except for large amounts of analyte. For Ag and Mn, the appearance temperatures and peak temperatures are not significantly affected by the plasma relative to the response obtained using a graphite furnace. For Pb, appearance and peak temperatures are shifted significantly earlier. For Pb, atom formation may be effected by the presence of CO in the gas phase generated from oxidation of the graphite furnace wall and electrode. The role of carbon in atom formation was studied by depositing the sample on both tungsten and graphite electrodes.}, keywords = {ASCORBIC-ACID, ATOMIC-ABSORPTION, DOUBLE PEAKS, ELECTROTHERMAL ATOMIZATION, FAPES, FURNACE ATOMIZATION PLASMA EXCITATION SPECTROMETRY, GRAPHITE FURNACE, GRAPHITE-FURNACE, LEAD AND MANGANESE SIGNALS, MECHANISMS, silver, SURFACE, TEMPERATURE, vaporization}, isbn = {0267-9477}, url = {://A1992JY53200002}, author = {Hettipathirana, T. D. and Blades, M. W.} } @article {6826, title = {INTERACTION OF MUONIUM WITH OXYGEN ON SILICA POWDER SURFACES}, journal = {Hyperfine Interactions}, volume = {65}, number = {1-4}, year = {1990}, note = {ISI Document Delivery No.: EZ856Times Cited: 10Cited Reference Count: 215TH INTERNATIONAL CONF ON MUON SPIN ROTATION RELAXATION AND RESONANCEAPR 09-12, 1990OXFORD, ENGLAND}, pages = {811-817}, type = {Proceedings Paper}, abstract = {Results of the first mu-SR studies using Merck FO Optipur silica powder, which contains paramagnetic impurities at the ppb level and has a surface area of 610 +/- 20 m2/g, are reported. Above 20 K, the transverse field muonium relaxation rate is roughly constant at 0.5 mu-s-1. Upon the addition of oxygen at ppm levels, the relaxation rate increases linearly with O2 concentration in the temperature range from 40-100 K yielding two-dimensional depolarization rate constants on the order of 10(-4) cm2 molecule-1 s-1. As the temperature is increased further, both oxygen and muonium desorb from the surface yielding a three-dimensional rate constant at 300 K of 3.1(3) x 10-10(-10) cm3 molecule-1 s-1, in agreement with the gas phase value. Longitudinal field measurements suggest that MuO2 is formed and is able to spin exchange with other oxygen molecules.}, keywords = {TEMPERATURE}, isbn = {0304-3843}, url = {://A1990EZ85600009}, author = {Kempton, J. R. and Marzke, R. F. and Fleming, Donald G. and Gonzalez, A. C. and Leung, S. K. and Pan, J. J. and Percival, P. W. and Senba, M. and Tempelmann, A.} }