J. Appl. Cryst.の発刊に際して

A comprehensive review on PEM water electrolysis

Economic Control of Quality of Manufactured Product.

Chromium occurrence in the environment and methods of its speciation.

Ultrathin metal films and particles on oxide surfaces: structural, electronic and chemisorptive properties

The crystal structures of strontium diformate in space groups P212121 (α form, 295 K), P41212 (β form, 334 and 540 K) and I41/amd (δ form, 605 K), and strontium fumarate in space groups Fddd (β form, 105 K) and I41/amd (α form, 293 K) have been determined from synchrotron X-ray powder diffraction data. Except for the α-strontium diformate, all the structures are based on a diamond-like Sr-ion arrangement, as in strontium acetylene dicarboxylate. The formate ions are disordered in the δ phase owing to steric hindrance. The fumarate ions are disordered over four (α) or two (β) symmetry-equivalent orientations. α-Strontium fumarate crystallizes with a unique 90° carboxylate dihedral angle, and is stable up to 773 K.

Structures of strontium diformate and strontium fumarate. A synchrotron powder diffraction study

On the possibility to improve the performance of flow injection analysis by deconvolution of spectrophotometric data.

A method is presented for trace-element analysis of lead and zinc by potentiometric stripping analysis (PSA) where both the glassy-carbon working electrode and the electrolyte are free of mercury. Analysis of zinc requires an activation of the glassy-carbon electrode. The activation is performed by pre-concentrating zinc on glassy carbon at −1400 mV(SCE) in a mercury-free electrolyte containing 0.1 M HCl and 2 ppm Zn2+, followed by stripping at approx. −1050 mV. A linear relationship between stripping peak areas, recorded in the derivative mode, and concentration was found in the range 0–2000 ppb.

Analysis of lead and zinc by mercury-free potentiometric stripping analysis

The influence of surface drift velocities on in situ scanning tunnelling microscopy (STM) experiment with atomic resolution is analysed experimentally and mathematically. Constant drift velocities much smaller than the speed of scanning can in many in situ STM experiments with atomic resolution result in an surface reconstraction. It is shown that a surface atomic structure can be distorted and observed as another atomic structure entirely owing to a velocity in the plane of the surface. The image can be resolved mathematically and the components of the drift velocity as well as the vectors of the non-distorted surface lattice can be determined. The calibration of distances can thus be carried out also when the image is influenced by drift. Results with gold surfaces and graphite surfaces are analysed and discussed.

Analysis and calibration of in situ scanning tunnelling microscopy images with atomic resolution influenced by surface drift phenomena

EURAMET and the European Commission ́s IMEP programmes [1, 2], together with the Institute of Reference Materials and Measurement [3], have elucidated the challenges related to reaching compliance between results for the same sample obtained in different laboratories (industrial and/or academic). Interlaboratory comparisons showed that customers had a high risk of receiving significantly different results from independent professional laboratories, which should not happen given the advanced technologies available in contemporary analytical chemistry laboratories. It was further demonstrated that results differed significantly not only when samples were analysed by different instruments and procedures but also when they were analysed by identical methods. It seemed that this was a genuine scientific issue that needed attention from scientists able to evaluate accepted statistical procedures. As a first approach, the celebrated EURACHEM/CITAC guide [4] to quantify uncertainty in analytical measurements and the VIM guide [5] allowed scientists to check the traceability of measurements by establishing uncertainty budgets for their methods. The introduction of the concept of ‘uncertainty’ is now a key factor in experimental work. Secondly, the concept of certified reference materials was introduced and is now an integral aspect of analytical chemistry and a growing industry, where certificated values for many analytes in various mixtures (matrices) are available. The latter approach has provided much greater confidence in many analytical methods. The philosophy of measurement is that the true amount of an analyte in a sample is not known but everyone makes a reliable estimate of the amount and the uncertainty of measurement is also estimated correctly. The result obtained as the mean value from results submitted by several laboratories is then announced as the consensus value. Right or wrong, the result represents the combined effort of all laboratories and all results have the same eligibility since they belong to the same distribution. With this philosophy of ‘consensus science’ in mind, it becomes possible to arrive at compliance or agreement between analytical results, an idea which also has significance beyond the analytical community itself. Consensus science should be discussed as a future framework for scientific methodology.

Jens Enevold Thaulov Andersen

Papers

Structures of strontium diformate and strontium fumarate. A synchrotron powder diffraction study

On the possibility to improve the performance of flow injection analysis by deconvolution of spectrophotometric data.

Analysis of lead and zinc by mercury-free potentiometric stripping analysis

Analysis and calibration of in situ scanning tunnelling microscopy images with atomic resolution influenced by surface drift phenomena

European analytical column no. 41.