Investigation of Deuterium Isotope Effects in the Carbon Dioxide Reforming of Methaneto Syngas over Rhodium Catalysts

Deuterium isotope effects in the CO2-reforming of methane to syngas were firstinvestigated over SiO2-supported rhodium catalysts. Normal deuterium isotop effect was morenoticeable on the methane conversion reaction than on the CO formation reaction, while there wasno such effect on the CO2 conversion reaction. It can be concluded that the dissociation of the C-Hbond in methane is a key mp and some CO is formed by the reverse water-gas shift reaction.

Protocol for Brain Magnetic Resonance Imaging and Extraction of Imaging‑Derived Phenotypes from the China Phenobank Project

Imaging-derived phenotypes(IDPs)have been increasingly used in population-based cohort studies in recent years.As widely reported,magnetic resonance imaging(MRI)is an important imaging modality for assessing the anatomical structure and function of the brain with high resolution and excellent soft-tissue contrast.The purpose of this article was to describe the imaging protocol of the brain MRI in the China Phenobank Project(CHPP).Each participant underwent a 30-min brain MRI scan as part of a 2-h whole-body imaging protocol in CHPP.The brain imaging sequences included T1-magnetization that prepared rapid gradient echo,T2 fuid-attenuated inversion-recovery,magnetic resonance angiography,difusion MRI,and resting-state functional MRI.The detailed descriptions of image acquisition,interpretation,and post-processing were provided in this article.The measured IDPs included volumes of brain subregions,cerebral vessel geometrical parameters,microstructural tracts,and function connectivity metrics.

QUADRILATERAL FINITE ELEMENTS FOR PLANAR LINEAR ELASTICITY PROBLEM WITH LARGE LAME CONSTANT

In this paper, we discuss the quadrilateral, finite element approximation to the two-dimensional linear elasticity problem associated with a homogeneous isotropic elastic material. The optimal convergence of the finite element method is proved for both the L-2-norm and energy-norm, and in particular, the convergence is uniform with respect to the Lame constant lambda. Also the performance of the scheme does not deteriorate as the material becomes nearly incompressible, Numerical experiments are given which are consistent with our theory.

Responses of woody plant root and xylem sap ATP to soil drying

The ATP in roots and xylem sap of two woody plant species, Platycladus orientalis and Acacia auriculiformis, subjected to rapid and slow soil drying has been determined employing firefly luciferase ATP assay method (sensitivity is at 10-12 mol ATP L-1). The ATP levels in the two species were 1.6 nmol. gDW-1 and 0.6 nmol. gDW-1 in roots, and 5.6 μmol·m-3 and 8 μmol ·m-3 in xylem sap, respectively. When plants of P. orientalis and A. auriculiformis were subjected to rapid soil drying, respectively, as soil water content （SWC） decreased from the normal level ( 0.2.5 g·gDW-1) to 0.02 and 0.06 g·gDW-1, separately, plant water potential （ ψ ）dropped to - 4 and - 3.2 MPa, differently, the ATP in roots decreased 99.7% and 42%, respectively. When the rapidly dried soil was watered for up to 6 d, SWC and ψ, were found to recover to their normal levels, but ATP content in roots of P. orientalis and A. auriculiformis recovered by 10% and 23%, respectively. When plants

Root and xylem ABA changes in response to soil drying in two woody plants

Two woody plants, Platycladus orientalise (tolerant to drought) and Acacia auriculi-formis (sensitive to drought), have been subjected to rapid and slow soil drying. ABA levels in their roots and xylem sap have been determined using radioimmunoassay (RIA, sensitivity is 0.4 pmol per assay vial) with a monoclonal antibody against ( + )-ABA. ABA contents of P. orientalise and A. auriculiformis growing in well watered soil are 0.3 and 2.5 nmol-gDW-1 in

Stable direction recovery in single-index models with a diverging number of predictors

Large dimensional predictors are often introduced in regressions to attenuate the possible modeling bias. We consider the stable direction recovery in single-index models in which we solely assume the response Y is independent of the diverging dimensional predictors X when βτ 0 X is given, where β 0 is a p n × 1 vector, and p n →∞ as the sample size n →∞. We first explore sufficient conditions under which the least squares estimation β n0 recovers the direction β 0 consistently even when p n = o(√ n). To enhance the model interpretability by excluding irrelevant predictors in regressions, we suggest an e1-regularization algorithm with a quadratic constraint on magnitude of least squares residuals to search for a sparse estimation of β 0 . Not only can the solution β n of e1-regularization recover β 0 consistently, it also produces sufficiently sparse estimators which enable us to select "important" predictors to facilitate the model interpretation while maintaining the prediction accuracy. Further analysis by simulations and an application to the car price data suggest that our proposed estimation procedures have good finite-sample performance and are computationally efficient.

A TWO-STAGE ALGORITHM OF NUMERICAL EVALUATIONOF INTEGRALS IN NUMBER-THEORETIC METHODS

To improve the numerical evaluation of integrals in Number-Theoretic Methods, we give a two-stage algorithm. The main idea is that we distribute the points according to the variations of the quadrature on the subdomains to reduce errors. The simulations results are also given.

Active site of praseodymium orthovanadate catalyst in oxidative dehydrogenation of propane

The pure phase of praseodymium orthovanadate (PrVO\-4) has been prepared by the citrate method. The active site of PrVO\-4 was studied by ESR, NO_TPD, O\-2_TPD and 18 O\-2_isotope exchange methods. The results of ESR and NO_TPD confirmed the presence of V 4+ in the catalyst. 18 O\-2_isotope exchange was through a single exchange procedure. From the result of O\-2+TPD and the kinetic study of 18 O\-2_isotope exchange, one can reach a conclusion that the V 4+ species associated with oxygen vacancies are the site for O\-2 activation. The adsorbed O\-2 or O\+- are the active oxygen species in propane oxidative dehydrogenation.