测量不确定度及其在化学计量中的应用实例

介绍了测量不确定度的评定方法及其在基准试剂纯度、干涉滤光片波长标准物质、锌合金成分标准物质中的应用实例。     

THE PROBABILISTIC PROPERTIES OF THE NONLINEAR AUTOREGRESSIVE MODEL WITH CONDITIONAL HETEROSKEDASTICITY

1.IntroductionTakeseriesmodelswithconditionalheteroskedasticityarewidelyappliedinmanyareassuchasfinancialeconomicsandeconometrics.Consequently,thereisagrowingthetheoreticalinterestinthesemodels.Inthispaper,weareexclusivelyinterestedinthefollowingnonlinearautoregressivemodelwithconditionalheteroskedasticityat=rk(Xt~1,...Iac~p,01) eth(Xt~1,'IXo~~l02)(1.1)withthefollowingassumptions(i){Et}isasequenceofindependelltideticallydistributedrandomvariableswithacommonalmenteveryWherepositivedenistyi…     

Tails of waiting times and their bounds

Tails of distributions having the form of the geometric convolution are considered. In the case of light-tailed summands, a simple proof of the famous Cramér asymptotic formula is given via the change of probability measure. Some related results are obtained, namely, bounds of the tails of geometric convolutions, expressions for the distribution of the 1st failure time and failure rate in regenerative systems, and others. In the case of heavy-tailed summands, two-sided bounds of the tail of the geometric convolution are given in the cases where the summands have either Pareto or Weibull distributions. The results obtained have the property that the corresponding lower and upper bounds are tailed-equivalent. This revised version was published online in June 2006 with corrections to the Cover Date.     

A strong uniqueness theorem for planar vector fields

This work establishes a strong uniqueness property for a class of planar locally integrable vector fields. A result on pointwise convergence to the boundary value is also proved for bounded solutions.Dedicated to Constantine Dafermos on his 60^th birthdayWork supported in part by CNPq, FINEP, FAPESP and a Research Incentive Fund grant of Temple University.     

Impedance of faradeic process with partial charge transfer

The electrochemical impedance of charge-transfer reaction involving the stages of adsorption and desorption of intermediate partially charged substance is analyzed theoretically in the frequency-potential plane in order to study the possibility for measuring the partial charge transfer. The simplest case of adsorption two-electron transfer, namely, the Langmuir adsorption with liner dependence of reaction rate on the coverage, is considered. It is assumed that the partial charge transfer is independent of the electrode potential.     

Regioselective replacement of nitro groups in 2,4,6-trinitrotoluene under the action of alkanethiols. Synthesis of ortho-(alkylthio)-substituted nitrotoluenes and their oxidation to sulfoxides and sulfones

The reactions of 2,4,6-trinitrotoluene with alkanethiols in the presence of K₂CO₃ (the molar ratio of the reactants is 1 : 1 : 1) in dipolar aprotic solvents result in selective replacement of the ortho-nitro group to form 2-alkylthio-4,6-dinitrotoluenes, which can be oxidized to the corresponding sulfoxides or sulfones. The second ortho-nitro group can be replaced under the action of one more equivalent of alkanethiol on sulfides as exemplified in PhCH₂SH.     

Synthetic approaches to homochiral bicyclo[5.2.1]decanes based on d-camphor

The Reformatsky reaction of bornanic enone (10-nor-1-vinylcamphor) with ethyl iodoacetate followed by iodocyclization afforded tricyclic iodolactone. Fragmentation of the latter initiated by HgO—I₂ gave rise to bicyclic iodoxolactone. Attempts to perform cyclization of this iodoxolactone analogously to intramolecular alkylation of CH-acids with halogen-containing electrophiles failed.     

抛射体运动方程的非近似解的一种求法

给出一种在考虑地球自转情况下求解抛射体运动方程的非近似解的较简便方法。     

Survival Probabilities for Discrete-Time Models in One Dimension

We consider survival probabilities for the discrete-time process in one dimension, which is known as the Domany–Kinzel model. A convergence theorem for infinite systems can be obtained in the nonattractive case.