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21.
In the multiple-output regression context, Hallin et al. (Ann Statist 38:635–669, 2010) introduced a powerful data-analytical tool based on regression quantile regions. However, the computation of these regions, that are obtained by considering in all directions an original concept of directional
regression quantiles, is a very challenging problem. Paindaveine and Šiman (Comput Stat Data Anal 2011b) described a first elegant solution relying on linear programming techniques. The present paper provides another solution
based on the fact that the quantile regions can also be computed from a competing concept of projection regression quantiles, elaborated in Kong and Mizera (Quantile tomography: using quantiles with multivariate data 2008) and Paindaveine and Šiman (J Multivar Anal 2011a). As a by-product, this alternative solution further provides various characteristics useful for statistical inference. We
describe in detail the algorithm solving the parametric programming problem involved, and illustrate the resulting procedure
on simulated data. We show through simulations that the Matlab implementation of the algorithm proposed in this paper is faster than that from Paindaveine and Šiman (Comput Stat Data Anal
2011b) in various cases. 相似文献
22.
Gaëlle Le Fer Julien Babinot Davy‐Louis Versace Valrie Langlois Estelle Renard 《Macromolecular rapid communications》2012,33(23):2041-2045
We present a straightforward method to prepare amphiphilic graft copolymers consisting of hydrophobic poly(3‐hydroxyalkanoates) (PHAs) backbone and hydrophilic α‐amino‐ω‐methoxy poly(oxyethylene‐co‐oxypropylene) (Jeffamine®) units. Poly(3‐hydroxyoctanoate)‐co‐(3‐hydroxyundecenoate) (PHOU) was first methanolyzed to obtain the desired molar mass. The amino end groups of Jeffamine were converted into thiol by a reaction with N‐acetylhomocysteine thiolactone and subsequently photografted. This “one‐pot” functionalization prevents from arduous and time‐consuming functionalization of the hydrophilic precursor or tedious modifications of PHAs, thus simplifying the process. The amphiphilic nature of modified PHAs leads to water‐soluble copolymers exhibiting thermoresponsive behavior. 相似文献
23.
Davy JL Guigou-Carter C Villot M 《The Journal of the Acoustical Society of America》2012,131(6):4615-4624
The effect of the resilience of the steel studs on the sound insulation of steel stud cavity walls can be modeled as an equivalent translational compliance in simple models for predicting the sound insulation of walls. Recent numerical calculations have shown that this equivalent translational compliance varies with frequency. This paper determines the values of the equivalent translational compliance of steel studs which make a simple sound insulation theory agree best with experimental sound insulation data for 126 steel stud cavity walls with gypsum plaster board on each side of the steel studs and sound absorbing material in the wall cavity. These values are approximately constant as a function of frequency up to 400 Hz. Above 400 Hz they decrease approximately as a non-integer power of the frequency. The equivalent translational compliance also depends on the mass per unit surface area of the cladding on each side of the steel studs and on the width of the steel studs. Above 400 Hz, this compliance also depends on the stud spacing. The best fit approximation is used with a simple sound insulation prediction model to predict the sound insulation of steel stud cavity walls whose sound insulation has been determined experimentally. 相似文献
24.
An new program has been developed and implemented for data analysis of mass spectra obtained by use of the VG9000 glow-discharge mass spectrometer. The program, designed to run in a Windows 9X environment includes several tools for import and export of data, cluster generators, etc. An automated technique for the interpretation of mass spectra is also built into the program; this enables faster and operator-independent interpretation. When major interferences or not-well defined signals are involved, the automated technique might fail to find the correct result. Therefore, a manual, VG9000 software-like, bypass is at hand. A comparison of the different techniques and programs shows, in general, comparable results. An installable version of the software is available on the university FTP-server (ftp://PLASMA-FTP.uia.ac.be/ private/imsas/). 相似文献
25.
Analytical and Bioanalytical Chemistry - 相似文献
26.
27.
Davy L S Nieskens Francisco Ample-Navarro Maarten M M Jansen Daniel Curulla-Ferré Josep Ricart Hans Niemantsverdriet 《Chemphyschem》2006,7(5):1068-1074
The decomposition of acetylene on a Rh(100) single crystal was studied by a combination of experimental techniques [static secondary ion mass spectrometry (SSIMS), temperature-programmed desorption (TPD), and low-energy electron diffraction (LEED)] to gain insight into the reaction pathway and the nature of the reaction intermediates. The experimental techniques were combined with a computational approach using density functional theory (DFT). Acetylene adsorbs irreversibly on the Rh(100) surface and eventually decomposes to atomic carbon and gas-phase hydrogen. The combination of experimental and computational results enabled us to determine the most likely reaction pathway for the decomposition process. 相似文献
28.
Density functional theory (DFT) calculations have been performed to determine the interaction energy between a CO probe molecule and all atoms from the first three rows of the periodic table coadsorbed on Rh(100), Pd(100) and Ir(100) metal surfaces. Varying the coverage of CO or the coadsorbed atom proved to have a profound effect on the strength of the interaction energy. The general trend, however, is the same in all cases: the interaction energy becomes more repulsive when moving towards the right along a row of elements, and reaches a maximum somewhere in the middle of a row of elements. The absolute value of the interaction energy between an atom-CO pair ranges from about -0.40 eV (39 kJ mol(-1)) attraction to +0.70 eV (68 kJ mol(-1)) repulsion, depending on the coadsorbate, the metal and the coverage. The general trend in interaction energies seems to be a common characteristic for several transition metals. 相似文献
29.
30.
Ian C. Watson André Schumann Haoyang Yu Prof. Dr. Emma C. Davy Dr. Robert McDonald Dr. Michael J. Ferguson Prof. Dr. Christian Hering-Junghans Prof. Dr. Eric Rivard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(41):9678-9690
New N-heterocyclic olefins (NHOs) are described with functionalization on the ligand heterocyclic backbone and terminal alkylidene positions. Various PdII–NHO complexes have been formed and their use as pre-catalysts in Buchwald–Hartwig aminations was explored. The most active system for catalytic C−N bond formation between hindered arylamine and arylhalide substrates was accessed by combining a backbone methylated NHO with [Pd(cinnamyl)Cl]2 in the presence of NaOtBu as a base. In these active systems evidence suggests that catalysis is mediated by colloidal palladium metal, highlighting a different coordination ability of NHOs in comparison with commonly used N-heterocyclic carbene co-ligands. 相似文献