Распределение примесных ионов в поверхностных слоях диэлектриков, модифицированных ионными пучками

The results of studies of impurity ions distribution in surface layers of dielectric modified by ion beams are presented. Depth profiles were measured by secondary ion mass spectrometry method. Computer simulations of the expected ion depth profile were carried out using the TRIM program. The alumina ceramic implanted with Ti ions at energy 50 keV and zirconium ceramic implanted with Al ions at energy 78 keV were investigated in our work

On the Role of Metal Contaminants in Catalyses with FeCl

Warning: Catalyzed N-, O-, and C-arylation reactions ascribed to FeCl3 can instead result from catalysis by trace quantities of copper salts.Fonds der Chemischen Industrie (Germany)National Institutes of Health (U.S.) (GM46059)National Institutes of Health (U.S.) (58160

Calixarene alpha-ketoacetylenes: versatile platforms for reaction with hydrazine nucleophile

Late stage diversification of calix[4]arenes and thiacalix[4]arenes with heterocycles remains a significant synthetic challenge and hampers further exploitation of the scaffolds. Here we describe the development of a short and facile synthetic route to conformationally diverse novel calix[4]arene and thiacalix[4]arene ynones using a palladium cross coupling approach (5% Pd(II) + 10% Cu(I)) with benzoyl chloride. Their successful conversion to heterocycles to afford pyrazoles was demonstrated through treatment with hydrazine. Functionalisation is calixarene conformation and linker independent enabling access to a library of structures

Gas-phase chemistry of molecular containers

The remarkable technical advances in mass spectrometry during the last decades, including soft ionisation techniques, the coupling of electrospray ionisation to flow reactors, and the broad scope of tandem mass spectrometric experiments applicable to mass-selected ions allow investigating the chemistry of molecular capsules in solution as well as in the absence of any environment. With these methods, mass spectrometry is capable of answering many questions starting from providing analytical characterisation data (elemental composition, stoichiometry, etc.) to structural aspects (connectivities, positions of building blocks in supramolecular complexes) and to the examination of solution and gas-phase reactivity including reactions inside molecular containers. The present article reviews this work with a focus rather on the chemical questions that can be answered than on the technical specialities of (tandem) mass spectrometry

Kamus Kependudukan

studi tentang kependudukan dan lingkungan hidup merupakan bidang kajian yang multidisiplin ilmu, baik eksakta maupun maupun noneksakta