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1.
The use of (certified) reference materials and quality control materials can form a suitable basis for evaluating measurement uncertainty of routine measurements. In particular when these materials are used for quality control purposes, it is not always evident how the quality control data can be used in the uncertainty budget of a routine measurement. Current guidance documents on the evaluation of measurement uncertainty and the use of reference materials treat this subject only in part, or in very generic terms. ISO/REMCO has established a new working group that will provide practical guidance and examples on how to use quality control data in the evaluation of measurement uncertainty. A short introduction to the subject is given.
相似文献
Adriaan M. H. van der VeenEmail: Phone: +31-15-2691733Fax: +31-15-2691670 |
2.
H. P. Zhang L. C. Yang L. J. Fu Q. Cao D. L. Sun Y. P. Wu R. Holze 《Journal of Solid State Electrochemistry》2009,13(10):1521-1527
Recent progress in studies of several types of core-shell structured electrode materials, including TiO2/C, Si/C, Si/SiO
x
, LiCoO2/C, and LiFePO4/C nanocomposites, including details of their preparation and their electrochemical performance is briefly reviewed. Results
clearly show that the coating shell can effectively prevent the aggregation of the nanosized cores, which are the electrochemically
active materials. In addition, the diffusion coefficients of lithium ions can be increased, and the reversibility of lithium
intercalation and deintercalation is improved. As a result, the cycling behavior is greatly improved. The reviewed results
suggest that core-shell nanocomposites are a good starting point for further development of new promising electrode materials.
相似文献
Y. P. WuEmail: |
R. Holze (Corresponding author)Email: |
3.
Lightweight polydicyclopentadiene (pDCPD) based aerogels were developed via a simple sol-gel processing and supercritical
drying method. The uniform pDCPD wet gels were first prepared at room temperature and atmospheric pressure through ring opening
metathesis polymerization (ROMP) incorporating homogeneous ruthenium catalyst complexes (Grubbs catalyst). Gelation kinetics
were significantly affected by both catalyst content and target density (i.e., solid content), while gel solvents also played
important role in determining the appearance and uniformity of wet gel and aerogel products. A supercritical carbon dioxide
(CO2) drying method was used to extract solvent from wet pDCPD gels to afford nanoporous aerogel solid. A variety of pDCPD based
aerogels were synthesized by varying target density, catalyst content, and solvent and were compared with their xerogel analogs
(obtained by ambient pressure solvent removal) for linear shrinkage and thermal conductivity value (1 atm air, 38 °C mean
temperature). Target density played a key role in determining porosity and thermal conductivity of the resultant pDCPD aerogel.
Differential scanning calorimetery (DSC) demonstrated that the materials as produced were not fully-crosslinked. The pDCPD
based aerogel monoliths demonstrated high porosities, low thermal conductivity values, and inherent hydrophobicity. These
aerogel materials are very promising candidates for many thermal and acoustic insulation applications including cryogenic
insulation.
相似文献
George L. GouldEmail: |
4.
Seven columns with embedded polar functionality were evaluated for use in liquid chromatography with a focus on molecular
shape recognition. Tests based on Standard Reference Material 869b Column Selectivity Test Mixture for Liquid Chromatography
and the Tanaka test indicate that only two of the phases are slightly shape selective at 20 °C. The shape recognition characteristics
of the phases appear to be directly related to the density of the embedded polar ligands and the temperature of the separation,
consistent with trends observed with conventional hydrocarbon phases.
Catherine Rimmer is a Research Chemist at the National Institute of Standards and Technology where she began as a National Research Council Postdoctoral Fellow. Her research efforts are currently directed towards an improved understanding of chromatographic processes to advance the “state of the art” in chemical metrology. 相似文献
Catherine A. RimmerEmail: |
Catherine Rimmer is a Research Chemist at the National Institute of Standards and Technology where she began as a National Research Council Postdoctoral Fellow. Her research efforts are currently directed towards an improved understanding of chromatographic processes to advance the “state of the art” in chemical metrology. 相似文献
5.
Xavier Fuentes-Arderiu 《Accreditation and quality assurance》2006,11(12):640-643
Protometrology is a new term recently proposed to designate the science of observation. As any field of knowledge needs a
terminological system, in this article a system of terms and definitions on protometrology, with examples belonging to clinical
laboratory sciences, is presented. This terminological system starts with the definitions of the two primitive concepts “object”
and “property”.
相似文献
Xavier Fuentes-ArderiuEmail: |
6.
This paper describes the COMAR database for certified reference materials (CRMs). The Web-based version of COMAR is freely
accessible via the Internet. COMAR was established to assist laboratories in finding the CRMs needed. The database is maintained
in a collaboration of the world’s major CRM producers. The planned changes in the database as agreed at the last COMAR council
meeting in Prague in May 2006 are indicated.
相似文献
Thomas SteigerEmail: |
7.
Michael Thompson 《Accreditation and quality assurance》2008,13(8):479-482
The currently recommended design of collaborative trials (interlaboratory method performance studies) is examined in relation
to the usefulness of the resulting statistics. It is suggested that larger experiments, without duplicate analysis, would
be more informative.
相似文献
Michael ThompsonEmail: |
8.
Hinne Hettema 《Foundations of Chemistry》2008,10(2):135-142
Michael Weisberg’s recent 2007 paper on the chemical bond makes the claim that the chemical notion of the covalent bond is
in trouble. This note casts doubts on that claim.
相似文献
Hinne HettemaEmail: |
9.
Vaporization enthalpies for the isomeric diazines were discussed within the context of recent measurements and estimation
techniques. It is suggested that pyridazine shows enigmatic behavior.
相似文献
Joel F. Liebman (Corresponding author)Email: |
10.
Daniela Aiello Luca Malfatti Tongjit Kidchob Rosario Aiello Flaviano Testa Iolinda Aiello Mauro Ghedini Massimo La Deda Tonino Martino Maria Casula Plinio Innocenzi 《Journal of Sol-Gel Science and Technology》2008,47(3):283-289
Highly fluorescent materials have been prepared by incorporation of a zinc complex in mesoporous silica thin films with ordered
pore structure. The zinc complex has been introduced into the mesoporous materials via impregnation in an ethanol solution.
The incorporation into the films has been monitored by UV–Vis, Fourier transform infrared spectroscopy and spectroscopic ellipsometry.
After 18 h of immersion in the doping solution the films showed strong blue emission, increase in the refractive index. Leaching
experiments performed by immersing the samples in ethanol or tetrahydrofuran have shown that the chromophore is retained in
the porous matrix.
相似文献
Plinio InnocenziEmail: |
11.
Guy Yardeni Israel Zilbermann Eric Maimon Haim Cohen Dan Meyerstein 《Research on Chemical Intermediates》2009,35(4):543-554
A new CeIII complex was synthesized by mixing the ligand “dioxocyclam” with CeIII ions at pH 8.0 and its redox properties were investigated.
相似文献
Dan Meyerstein (Corresponding author)Email: |
12.
René Dybkaer 《Accreditation and quality assurance》2007,12(12):661-663
Terminology within a small laboratory community can be informal without danger of misunderstanding, but communication with
a wider audience and not least in publications, needs unequivocal terms for defined concepts. As an example, the many meanings
of “concentration” are explored to present a systematic nomenclature, including a concept diagram.
相似文献
René Dybkaer |
13.
Stress generation and fracture in lithium insertion materials 总被引:1,自引:0,他引:1
A mathematical model that calculates volume expansion and contraction and concentration and stress profiles during lithium
insertion into and extraction from a spherical particle of electrode material has been developed. The maximum stress in the
particle has been determined as a function of dimensionless current, which includes the charge rate, particle size, and diffusion
coefficient. The effects of pressure-driven diffusion and nonideal interactions between the lithium and host material have
also been described. The model predicts that carbonaceous particles will fracture in high-power applications such as hybrid-electric
vehicle batteries.
相似文献
John ChristensenEmail: |
14.
Yan Gao Sabrina Reischmann Johannes Huber Tobias Hanke Rudolf Bratschitsch Alfred Leitenstorfer Stefan Mecking 《Colloid and polymer science》2008,286(11):1329-1334
Single semiconductor quantum dots were embedded into polymer particles with diameters below 0.1 μm by an emulsion polymerization
procedure or via a secondary dispersion approach. The photoluminescence properties of the nanocrystals are retained upon encapsulation,
as demonstrated by fluorescence confocal microscopy.
相似文献
Stefan MeckingEmail: |
15.
16.
The discovery and use of fluorescent proteins has revolutionized cellular biology. Despite the widespread use of visible fluorescent
proteins as reporters and sensors in cellular environments the versatile photophysics of fluorescent proteins is still subject
to intense research. Understanding the details of the photophysics of these reporters is essential for accurate interpretation
of the biological and biochemical processes illuminated by fluorescent proteins. Some aspects of the complex photophysics
of fluorescent proteins can only be observed and understood at the single-molecule level, which removes averaging inherent
to ensemble studies. In this paper we review how single-molecule emission detection has helped understanding of the complex
photophysics of fluorescent proteins.
相似文献
Vinod SubramaniamEmail: |
17.
Saad Alshehri John Burgess Colin D. Hubbard Christopher J. Jones Amit K. Das 《Transition Metal Chemistry》2008,33(4):417-420
The kinetics of substitution by alcohols and by aniline at [tris(3,5-dimethylpyrazolyl)hydroborato]molybdenum nitrosyl dihalides in toluene solution at 298.2 K and at atmospheric pressure
are reported and interpreted in terms of an associative mechanism.
相似文献
Colin D. HubbardEmail: |
18.
Marek Orlik 《Journal of Solid State Electrochemistry》2009,13(2):245-261
This review paper presents briefly the main concepts of nonlinear dynamics and their exemplary manifestations in selected
systems, including those important from the point of view of materials science. It is an extended version of the conference
presentation. The conditions of instabilities leading to spontaneous formation of dissipative structures are given. Principles
of nonlinear dynamics are illustrated with several examples from the homogeneous and heterogeneous and physical and chemical
systems: pattern formation in the convective motion of fluids subject to various kinds of driving forces, periodic precipitation
phenomena, oscillations, and pattern formation in the Belousov–Zhabotinski (BZ) reaction and the catalytic oxidation of thiocyanate
ions with hydrogen peroxide, as well as bistability and tristability in the electrochemical reduction of azide complexes of
nickel(II). The application of nonlinear dynamics in materials science is first exemplified by its role in polymerization
reactions. Such processes can either exhibit internal couplings leading to oscillations or can be coupled with the chemical
oscillatory process through, e.g., the covalent bonding of its catalyst to the polymer network. Other selected examples of
the application of nonlinear dynamics in materials science, referring to electrochemical processes, were briefly reviewed.
Nonlinear dynamics appears to be useful for designing new materials, including those at the nanoscale.
相似文献
Marek OrlikEmail: |
19.
Decision-making in the conformity assessment of exhaust gas analysers with due account of measurement uncertainty and limited sampling is considered. Risks of incorrect decisions where test results lie in the vicinity of a specification limit are assessed in terms of percentage probability and the costs of measurement and environmental consequences, with examples based on the metrological requirements on these analysers stipulated in the new EU Measurement Instrument Directive. An optimised uncertainty methodology is proposed for the first time in legal metrology based on quantitative testing of new instruments for type approval and initial verification, and gives valuable insight into traditional rules limiting uncertainty in conformity assessment in general. Further, an analysis of subsequent verification of exhaust gas analysers in use in society, leads to a new optimised uncertainty methodology based on attribute sampling.
相似文献
L. R. PendrillEmail: Phone: +46-33-165444Fax: +46-33-165620 |
20.
Michael Noyong Buelent Ceyhan Christof M. Niemeyer Ulrich Simon 《Colloid and polymer science》2006,284(11):1265-1273
The formation and the optical features of two-dimensional aggregates formed by DNA-directed immobilization and cross-linking of bifunctional DNA–gold nanoparticles at flat gold substrates are analyzed. The samples are structurally characterized by atomic force microscopy to evaluate the particle size, the particle densities, and the degree of aggregation. The optical characteristics determined by UV/visible measurements are correlated with the structural features observed.
相似文献
Ulrich SimonEmail: |