Spécifications des algorithmes de triangulation de systèmes algébro-élémentairesSpecifications for triangulation algorithms of elementary-algebraic systems

We formalize worthwhile specifications for triangular elementary-algebraic systems in order to minimize the importance of the elementary part. An algorithmic application is given. To cite this article: A.-M. Bellido, V. Jalby, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 155–159     

Cesium,manganese and cobalt water–sediment transfer kinetics and diffusion into mangrove sediments inferred by radiotracer experiments

A study on the trace elements transfer from tidal water to mangrove sediments from Guanabara Bay (southeastern Brazil) was performed in laboratory microcosms. Sediment cores were covered with tidal water spiked with ¹³⁷Cs, ⁵⁴Mn and ⁵⁷Co during 5-h experiments, and water samples were taken at regular intervals to measure uptake kinetics at the sediment–water interface. At the end of the experiments, the uptake and diffusional penetration into the sediments was evaluated. Half-removal times from water to sediments were slightly higher for ¹³⁷Cs (3.4 ± 1.7 h) than observed for ⁵⁴Mn (2.3 ± 0.2 h) and ⁵⁷Co (2.6 ± 1.1 h). After these experiments, all radioisotopes presented decreasing activities with increasing sediment depth, being the distribution of ¹³⁷Cs indicative of higher diffusion within the upper 2 cm. This study on the removal of ¹³⁷Cs, ⁵⁴Mn and ⁵⁷Co from tidal water by mangrove sediments suggests that while ⁵⁷Co and ⁵⁴Mn presented closer behaviors, there was a slightly higher mobility of ¹³⁷Cs.     

Advances on structuring, integration and magnetic characterization of molecular nanomagnets on surfaces and devices

This critical review represents a concise revision of the different experimental approaches so far followed for the structuration of molecular nanomagnets on surfaces, since the first reports on the field more than ten years ago. Afterwards, a presentation of the different experimental approaches followed for their integration in sensors is described. Such work involves mainly two families of sensors and devices, microSQUIDs sensors and three-terminal devices for single-molecule detection. Finally the last section is devoted to a detailed revision of the different experimental techniques that can be used for the magnetic characterization of these systems on surfaces, ranging from magnetic circular dichroism to magnetic force microscopy. The use of these techniques to characterize other nanostructured magnetic materials, such as nanoparticles, is also revised. The aim is to give a broad overview of the last advances achieved with these techniques and their potential and evolution over the next years.     

ICP-AES法测定色漆可溶性金属含量

用ICP-AES法测定了色漆中的“可溶性”金属铬、镉、铅元素，考察了不同酸度对分析结果的影响，优化了测试条件。进行了回收率和精密度试验。并用原子吸收光谱国标方法进行对照，结果一致。     

A new method for the titrimetric determination of the ferricyanide ion

The direct titration of ferricyanide ions with the mercurous-thiocyanate system is studied, the influence of pH, thiocyanate concentration, time and temperature being considered. The standard deviation of the proposed method is 0.26 per cent.     

Homo- and heterodinuclear 2,2′-bipyrimidine-bridged complexes

[M(hfacac)₂(bpym)] complexes, where M = Co^II, Ni^II or Zn^II, hfacac = hexafluoroacetylacetonate and bpym = 2,2bipyrimidine; and [Cl₂M(bpym)M(hfacac)₂] complexes, where M = Co^II, Ni^II Mn^II or ZnII M = Ni^II; M = NiII or Zn^II and M = Zn^II; M = Ni^II and M = Co^II have been prepared and characterized by chemical analysis, conductance measurements, IR and electronic spectroscopies and magnetic susceptibility measurements (4.2–292K range). The dinuclear NiII–Ni^II, Co^II–Ni^II and Mn^II–Ni^II complexes are antiferromagnetic, with an intramolecular exchange parameter, J, of –2.3–8.9cm–1. Co^II and Mn^II are in a high spin state. The low temperature effect observed in monomers and in Ni^II–Zn^II dimers is considered a consequence of either an intermolecular antiferromagnetic interaction or the zero-field splitting in NiII.     

Synthesis,spectroscopic studies and magnetic properties of binuclear complexes of the first transition series cations bridged by 2,2′-bipyrimidine

Binuclear complexes [M₂Cl₄(-bpym)], where M = VO²⁺, Fe^II, Co^II or Cu^II and bpym = 2,2-bipyrimidine, and [M₂(hfacac)₄(-bpym)] complexes, where hfacac = hexafluoroacetylacetonate and M = Fe^II, Ni^II or Co^II have been synthesized and characterized by chemical analysis, conductance measurements, i.r., electronic and e.p.r spectroscopies and by magnetic susceptibility measurements (in the 4.2–291K range). Co^II and Fe^II are in a high spin state. [(VO)₂Cl₄(-bpym)] is paramagnetic, without significant interactions. [Fe₂Cl₄(-bpym)] shows a singular behaviour explained by an antiferromagnetic intradimer exchange and a ferromagnetic interdimer interaction. All other complexes are antiferromagnetic, with an intramolecular exchange parameter, J, varying from –3.3 cm^–1 for Co^II/math> to –109 cm^–1 for Cu^II.