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991.
We describe a method for solving the maximum likelihood estimate problem of a mixing distribution, based on an interior cutting plane algorithm with cuts through analytic centers. From increasingly refined discretized statistical problem models we construct a sequence of inner non-linear problems and solve them approximately applying a primal-dual algorithm to the dual formulation. Refining the statistical problem is equivalent to adding cuts to the inner problems. 相似文献
992.
993.
C. Driemeier K.P. Bastos G.V. Soares L. Miotti R.P. Pezzi I.J.R. Baumvol P. Punchaipetch G. Pant B.E. Gnade R.M. Wallace 《Applied Physics A: Materials Science & Processing》2005,80(5):1045-1047
HfSiO and HfSiON films with thicknesses compatible with the requirements for gate dielectrics alternatives to SiO2 in ultra-large scale integration silicon-based CMOSFET devices were deposited on an ultrathin HfSiO15N interfacial layer on Si(001). These structures were submitted to thermal processing routines typical of post-deposition annealing and dopant activation steps in fabrication technology, namely at 450 or 1000 °C, respectively, and in atmospheres of N2 and/or O2. N transport and loss were determined by nuclear reaction analysis, including sub-nanometric depth resolution profiling with narrow nuclear reaction resonances. The chemical states of N were accessed by angle-resolved X-ray photoelectron spectroscopy. After annealing at 450 °C, N is seen to be mobile, whereas the chemical environment of N is not changed at this temperature. Annealing at 1000 °C renders N mobile and its most abundant chemical state in near-surface regions is unstable. Annealing in O2 atmosphere promotes incorporation of O from the gas phase into the films, partly in exchange for N and O atoms and partly by net incorporation of oxygen in the films. The profiles of the newly incorporated O atoms are also determined with sub-nanometric depth resolution by narrow nuclear reaction resonance profiling. PACS 68.60.-p; 68.55.-a; 73.61.Ng; 73.40.Qv 相似文献
994.
Caio M. Paranhos Karim Dahmouche Soraia Zaioncz Bluma G. Soares Luiz A. Pessan 《Journal of polymer science. Part A, Polymer chemistry》2008,46(23):2618-2629
Poly(vinyl alcohol)/montmorillonite (PVA/MOM) hydrogels containing coacervated microparticles of sulfonated polyester (PES) were prepared by direct mixture of the components in water. The system was characterized by using differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), and dynamical mechanical analysis (DMA). The influence of PES and MOM on the microstructure of the nanocomposite hydrogels was established. The presence of PES causes a significant change on the crystallinity of PVA. Furthermore, the presence of MOM leads to a hierarchical nanostructure that also contributes to change the crystallinity of PVA. The results of structural investigation are correlated with the mechanical properties of the composites obtained by DMA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2618–2629, 2008 相似文献
995.
D. C. Menezes F. T. Vieira G. M. de Lima J. L. Wardell M.E. Corts M. P. Ferreira M. A. Soares A. Vilas Boas 《应用有机金属化学》2008,22(4):221-226
The in vitro antifungal activity of the dithiocarbamate organotin complexes [Sn{S2CN(CH2)4}2Cl2] ( 1 ), [Sn{S2CN(CH2)4}2Ph2] ( 2 ), [Sn{S2CN(CH2)4}Ph3] ( 3 ), [Sn{S2CN(CH2)4}2n‐Bu2] ( 4 ), [Sn{S2CN(CH2)4}Cy3] {Cy = cyclohexyl} ( 5 ), [Sn{S2CN(C2H5)2}2Cl2] ( 6 ), [Sn{S2CN(C2H5)2}2Ph2] ( 7 ), [Sn{S2CN(C2H5)2}Ph3] ( 8 ), [Sn{S2CN(C2H5)2}3Ph] ( 9 ) and [Sn{S2CN(C2H5)2}Cy3] ( 10 ) has been screened against Candida albicans (ATCC 18804), Candida tropicalis (ATCC 750) and resistant Candida albicans collected from HIV‐positive Brazilian patients with oral candidiasis. All compounds exhibited antifungal activities and complexes 3 and 8 displayed the best results. We have investigated the effect of compounds 1–10 on the cellular activity of the yeast cultures. Changes in mitochondrial function have not been detected. However, all drugs reduced ergosterol biosynthesis. Preliminary studies on DNA integrity indicated that the compounds do not cause gross damage to yeast DNA. The data suggest that these compounds share some mechanisms of action on cell membranes similar to that of polyene but not with azole drugs, normally used in Candida infections. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
996.
In this article, numerical ranges associated with operators on an indefinite inner product space are investigated. Boundary generating curves, corners, shapes and computer generations of these sets are studied. In particular, the Murnaghan-Kippenhahn theorem for the classical numerical range is generalized. 相似文献
997.
In industry, most of the process observations are assumed to come from a normal population, but usually we merely want to control the process mean value. It is thus sensible to find control statistics, which are ‘robust’ to monitor the process mean, giving the expected rate of false alarms whenever that mean is close to the target value, although not under a normal regime. Simulation studies for a few symmetric and asymmetric distributions allow us to suggest the total median as a robust median estimator. We shall here analyse such a robustness, as well as the robustness of the total median chart comparatively to the sample mean chart, whenever we want to control the mean value of a symmetric underlying parent. Some indication is also provided on the comparative out‐of‐control behaviour of the two charts. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
998.
Helio J. C. Barbosa Carlile C. Lavor Fernanda M. P. Raupp 《Annals of Operations Research》2005,138(1):189-202
In this paper we propose a hybrid genetic algorithm for minimizing molecular potential energy functions. Experimental evidence
shows that the global minimum of the potential energy of a molecule corresponds to its most stable conformation, which dictates
its properties. The search for the global minimum of a potential energy function is very difficult since the number of local
minima grows exponentially with molecule size. The proposed approach was successfully applied to two cases: (i) a simplified
version of more general molecular potential energy functions in problems with up to 100 degrees of freedom, and (ii) a realistic
potential energy function modeling two different molecules. 相似文献
999.
We present a method to factorize a second order elliptic boundary value problem in a circular domain, in a system of uncoupled first order initial value problems. We use a space invariant embedding technique along the radius of the circle, in a decreasing way. This technique is inspired in the temporal invariant embedding used by J.-L. Lions for the control of parabolic systems. The singularity at the origin for the initial value problems is studied. A formal calculation for more general star-shaped domains is presented. To cite this article: J. Henry et al., C. R. Acad. Sci. Paris, Ser. I 339 (2004). 相似文献
1000.
Gabrielle Viennet 《Probability Theory and Related Fields》1997,107(4):467-492
This paper investigates the problem of density estimation for absolutely regular observations. In a first part, we state
two important results: a new variance inequality and a Rosenthal type inequality. This allows us to study the ?
p
-integrated risk, p≧ 2, of a large class of density estimators including kernel or projection estimators. Under the summability condition on the
mixing coefficients ∑
k≧ 0
(k+1)
p− 2
β
k
<∞, the rates obtained are those known to be optimal in the independent setting.
Received: 17 October 1995 / In revised form: 26 October 1996 相似文献