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O2 is black P structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of eight hydrogen peroxide molecules. O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.23 Å.
O2 is Cubic alpha N2-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is zero-dimensional and consists of two hydrogen peroxide molecules. O is bonded in a single-bond geometry to one O atom. The O–O bond length is 1.23 Å.
While Ni-rich Li[NixMnyCo1-x-y]O2 (NMC, x ? 0.8) compounds are considered the most promising cathode materials for high-energy lithium-ion batteries (LIBs), a significant challenge is the higher reactivities caused by the increased Ni content, especially under high-voltage operation conditions. In the present study, we synthesize three single-crystal NMC (SC-NMC) samples with the same particle size and morphology: LiNi0.8Mn0.1Co0.1O2 (NMC811), LiNi0.80Mn0.15Co0.05O2 (NMC80155) and LiNi0.85Mn0.10Co0.05O2 (NMC85105). By systematically varying the composition while controlling other properties, the role of each transition metal during air exposure, thermal treatment and long-term cycling is clearly demonstrated. We reveal that while higher Ni content leads to an overall increased reactivities, the presence of Mn provides a stabilizing effect on thermal, structural and chemical properties. In the absence of cycling-induced particle cracking, surface reconstruction is shown to be the dominating contributor to cathode capacity fade. Our study provides key insights needed for the development of better-performing Ni-rich NMC cathode materials.
Tabulated values of cavitation b-factor for helium, H2, N2, F2, O2, refrigerant 114, and H2O
Studying reaction N/plus/ plus O2 yields NO/plus/ plus O as function of collision energy using crossed beams
Nike-Apache rocket carrying radiometer for detection of O2 /a /1 Delta g//-/X /3 Sigma g plus// transition
Thermodynamic equilibrium constants of Fe-MgO-SiO2-O2 system reactions at one atmosphere and 900-1300 C
Data reduction procedures for determining free-stream and post-normal-shock flow conditions are presented. These procedures are applicable to flows of CO2, N2, O2, Ar, or mixtures of these gases and include the effects of dissociation and ionization. The assumption of thermochemical equilibrium free-stream and post-normal-shock flow is made. Although derived primarily to meet the immediate needs of an expansion tube of a hot gas radiation research facility, these procedures are applicable to any supersonic or hypersonic test facility using these gases or mixtures thereof. The data reduction procedures are based on combinations of three of the following flow parameters measured in the immediate vicinity of the test section: (1) stagnation pressure behind normal shock, (2) free-stream static pressure, (3) stagnation-point heat-transfer rate, (4) free-stream velocity, and (5) free-stream density. Thus, these procedures do not depend explicitly upon measured or calculated upstream flow parameters. The procedures are incorporated into a single computer program written in FORTRAN IV language. A listing of this computer program is presented, along with a description of the inputs required and a sample of the data printout.
Newly measured electron impact cross sections for excitation of the a 1 Delta g and b 1 Sigma g+ electronic states of O2 were employed to predict the absolute volume emission rates from these states under auroral conditions. A secondary electron electron flux typical of an IBC II nighttime aurora was used and the most important quenching processes were included in the calculations. The new excitation cross sections for the a 1 Delta g and b 1 Sigma g+ states are more than an order of magnitude larger than previous estimates, and lead to correspondingly greater intensities in the atmospheric and IR-atmospheric band systems. The calculated intensity ratios of the volume emission rates of 7621 A and 1.27 microns to that for 3914 A are smaller than obtained from aircraft observations and recent rocket experiments.
A kinetic analysis is presented of the data obtained in previously described kinetic experiments relating to the photoactivation of the Mn complex required for photosynthetic O2 evolution. The results obtained from the computer simulation of the derived kinetic model compare favorably with the experimentally derived values. They also suggest that photoactivation can be rationalized in terms of a two-quantum process.
A kinetic analysis is reported of the process of Mn photoactivation that the photosynthetic evolution of O2 requires. This process is investigated in Mn-deficient Anacystis nidulans cells. The implications are discussed of the results obtained.
Estimation of the aeronomically important cross section for the production of O(super 5 S super 0) by electron impact dissociation of O2 on the basis of recently published work of several groups. The cross section reaches a maximum value of 7 x 10 to the minus 18th sq cm plus or minus 50% at about 100 eV. The assumptions made in arriving at this cross section suggest several experiments which might be performed to further refine this estimate.
Study of the electron-impact excitation spectrum of O2 at 20 and 45 eV impact energies and at scattering angles ranging from 10 to 90 deg. The angular behavior of the differential scattering cross sections for excitation of the a super 1 delta sub g, b super 1 sigma sub g (+), B super 3 sigma sub u (-) states for the 9.97-eV ('longest' band) and the 10.29-eV ('second' band) transitions, for the broad feature at 6.1 eV energy-loss, and for elastic scattering is determined. The experimentally measured relative differential and integral cross sections for these processes are approximately normalized to the absolute scale. The intensities of the different transitions in optical and electron-impact spectra are compared, and the importance of spin-orbit coupling and exchange processes is discussed. It is found that the energy-loss feature at 6.1 eV in the electron-impact spectrum is mostly due to the excitation of the c super 1 sigma sub u (-) state, and not the A super 3 sigma sub u (+) state, as had been previously thought.
The rate constant (kl) of the reaction OH(v=o) + O3 yields HO2 + O2 measured over the temperature range 220 to 450 K at total pressures between 2 and 5 torr using ultraviolet fluorescent scattering for the detection of OH radicals. An Arrhenius expression was obtained, and the rate constant for the reaction HO2 + O3 yields OH + 2O2 was inferred to be less than 0.1 kl over the entire temperature interval.
Many properties of gaseous systems such as electromagnetic absorption and emission, sound dispersion and absorption, may be elucidated if the nature of collisions between the particles in the system is understood. A procedure for the calculation of the classical trajectories of two interacting diatomic molecules is described. The dynamics of the collision will be assumed to be that of two rigid rotors moving in a specified potential. The actual outcome of a representative sample of many trajectories at 298K was computed, and the use of these values at any temperature for calculations of various molecular properties will be described. Calculations performed for the O2 microwave spectrum are given to demonstrate the use of the procedure described.
A program to establish technology readiness of hydrogen-oxygen (H2-O2) auxiliary power units for use on board the space shuttle orbiter vehicle is discussed. Fundamental objectives include experimentally establishing an acceptable propellant flow control method, verification of combustor stability, and adequate thermal management. An initial APU configuration with recycled hydrogen flow has been studied and revised towards greater simplicity and scaling ease. The selected APU is a recuperated open-cycle, turbine-driven unit. Series flow of cryogenic hydrogen removes internally-generated heat and from the hydraulic system. Steady-state test of the combustor has been successful.
Newly measured electron impact cross sections for excitation of the a super 1 Delta sub g and b super 1 Sigma (plus) sub g electronic states of O2 have been employed to predict the absolute volume emission rates from these states under auroral conditions. A secondary electron flux typical of an IBC II nighttime aurora was used, and the most important quenching processes were included in the calculations. The new excitation cross sections for the a super 1 Delta sub g and b super 1 Sigma (plus) sub g states are more than an order of magnitude larger than previous estimates and lead to correspondingly greater intensities in the atmospheric and IR atmospheric band systems. The calculated intensity ratios of the volume emission rates of 7621 A and 1.27 micron to that for 3914 A are smaller than those obtained from aircraft observations and recent rocket experiments.
Dissociation continuum cross sections for N2 and O2 have been determined from previously measured total absorption and ionization cross sections. Several dissociation continuums were found for each molecule. Some of these continuums were attributed to specific dissociation products in which the dissociation products are in excited states. The upper-atmosphere emission rates resulting from these photodissociative excitation processes have been calculated for the N I 10,400-A and O I 1356-A lines. The results indicate, particularly for the oxygen line, that these photodissociative processes may be important in the dayglow.