Abstract: The invention concerns derivatives of calixarene having the formula: in which: R1 represents various hydrocarbon groups, R2 and R3 represent an alkyl, cycloalkyl or aryl group or a group having the formula: O(CH2)n[O(CH2)p]q OR4, or form a heterocyclic group with the nitrogen atom, and, n equals 6, 7 or 8. These derivatives can be used for extracting strontium from aqueous solutions.

Abstract: The invention relates to new calixarenes of formula: ##STR1## in which R.sup.1 represents a crown ether chain that includes at least two aryl or cycloalkyl rings,R.sup.2 is a hydroxyl or alkoxy group, or the two R.sup.2 groups together form a crown ether chain such as R.sup.1, and R.sup.3 represents a hydrogen atom or an alkyl group. The calixarenes are used to selectively extract caesium from aqueous solutions that notably have high concentrations of sodium.

Abstract: The invention relates to crown calix.vertline.4.vertline.arenes, their preparation process and their use for the selective extraction of cesium and actinides. These crown calixl4larenes comply with the formula: ##STR1## in which R.sub.1 represents a group of formula X(C.sub.2 H.sub.4 X).sub.m and X(C.sub.2 H.sub.4 X).sub.n YX(C.sub.2 H.sub.4 X).sub.n with X=O or N(R.sub.4), m=3, 4, 5 or 6, Y=cycloalkylene or arylene and n=1, 2 or 3. These crown.vertline.4.vertline.arenes, whose benzene nuclei are optionally substituted by alkyl groups, can be used as extractants, e.g. in liquid membrane form, for separating cesium from acid solutions containing sodium in a large quantity compared with the cesium quantity, e.g. irradiated fuel reprocessing plant effluents.

Abstract: Calix?4!arene compounds are disclosed that can be used as active components in a calcium sensitive sensor. The compounds exhibit strong calcium ion binding selectivity over sodium and potassium ions and they are stable during sterilization.

Abstract: A calix?4!arene compound, application of the compound as an active component in a calcium sensitive sensor, and a calcium sensitive sensor containing the compound. The sensor is not very sensitive to sodium and potassium ions.

Abstract: A resist film consisting of 5,11,17,23,29,35-hexachloromethyl-37, 38,39,40,41,42-hexamethoxycalix?6!arene sensitive to a high-energy beam and soluble to a solvent is formed on a substrate etchable by a dry etching, has a selective region thereof exposed to the high-energy beam, with a remaining region unexposed thereto, and developed to define a pattern on the substrate, as the remaining region is removed by the solvent, before the substrate with the pattern is subjected to the dry etching. A nanometric patterning and etching is permitted, with a reduced process time.