I. Détermination expérimentale et essai d'attribution des vibrations externes actives en infrarouge dans quelques carbonates métalliques a l'état cristallin

The absorption spectra of nine metal carbonates in powder form have been measured in the région 15 — 800 μ. On the basis of the expérimental results and of the possible coupling between vibrations of the same class, we propose to identify all the bands measured in the far infrared with external vibrations. The number of bands for the différent carbonates is considered to indicate the coupling intensity.Les spectres d'absorption de neuf carbonates métalliques étudiés à l'état de poudre dans la région 15 — 800 μ environ permettent une interprétation des vibrations externes. En nous aidant des données expérimentales, qui manquaient jusqu'alors, et en adoptant le principe du couplage entre les vibrations de même symétrie, nous proposons des identifications de toutes les bandes observées dans l'infrarouge lointain avec des vibrations externes. En passant d'un carbonate à un autre, la variation du nombre des bandes permet, à notre sens, de préciser l'intensité du couplage précité

II. — Détermination expérimentale et essai d'attribution des vibrations actives en infrarouge de quelques carbonates basiques métalliques à l'état cristallin

The absorption spectra of four basic carbonates in the powder state have been studied between 2 and 150 μ and enable to give assignment to the différent vibrations. It is however difficult to obtain a clear distinction between internal and external vibrations and the structural complexity of these elements leads to a global study of the spectrum. Any generalization is to proscribe in the study of basic salts.Les spectres d'absorption de 4 carbonates basiques, étudiés à l'état de poudre entre 2 et 150 μ, permettent de donner une attribution aux différentes vibrations. Toutefois, une distinction nette entre les vibrations internes et externes est difficile, une étude globale du spectre a été imposée par la complexité de structure de ces corps. Toute généralisation est à éviter dans l'étude des sels basiques

A Case Study In Evidence-Based DSL Evolution

International audienceDomain-specific languages (dsls) can significantly increase productivity and quality in software construction. However, even dsl programs need to evolve to accomodate changing requirements and circumstances. How can we know if the design of a dsl supports the relevant evolution scenarios on its programs? We present an experimental approach to evaluate the evolutionary capabilities of a dsl and apply it on a dsl for digital forensics, called DERRIC. Our results indicate that the majority of required changes to DERRIC programs are easily expressed. However, some scenarios suggest that the dsl design can be improved to prevent future maintenance problems. Our experimental approach can be considered first steps towards evidence-based dsl evolution

Triton X-100 concentration effects on membrane permeability of a single HeLa cell by scanning electrochemical microscopy (SECM)

Changes in HeLa cell morphology, membrane permeability, and viability caused by the presence of Triton X-100 (TX100), a nonionic surfactant, were studied by scanning electrochemical microscopy (SECM). No change in membrane permeability was found at concentrations of 0.15 mM or lower during an experimental period of 30 to 60 min. Permeability of the cell membrane to the otherwise impermeable, highly charged hydrophilic molecule ferrocyanide was seen starting at concentrations of TX100 of about 0.17 mM. This concentration level of TX100 did not affect cell viability. Based on a simulation model, the membrane permeability for ferrocyanide molecules passing though the live cell membrane was 6.5 ± 2.0 × 10-6 m/s. Cells underwent irreversible permeabilization of the membrane and structural collapse when the TX100 concentration reached the critical micelle concentration (CMC), in the range of 0.19 to 0.20 mM. The impermeability of ferrocyanide molecules in the absence of surfactant was also used to determine the height and diameter of a single living cell with the aid of the approach curve and probe scan methods in SECM