Investigation of high concentration effects of Sb and P in silicon by combination of SIMS and TEM

Summary The combination of SIMS, electrical resistance measurements and TEM was used for investigation of high concentration effects of Sb and P in silicon. For antimony implantation and annealing combined with and without preannealing were studied. The distributions and the precipitated fraction were determined by SIMS. TEM investigations showed that by preannealing at a temperature of 1150°C no dislocations but only precipitates are formed. Thus the precipitation kinetics for an isothermal case (1000°C) could be studied. The size distributions of precipitates were determined by image processing of plan view TEM micrographs. The kinetics of the precipitation process was simulated for the distribution function by a computer model and compared with experiments. A good agreement between experiment and simulation was obtained.For phosphorus, specimens implanted with medium and high doses were investigated. With medium doses small extrinsic dislocation loops (size 20–40 nm) were observed near the amorphous/cristalline boundary. The dislocation loops are formed by agglomeration of interstitial silicon atoms which are supersatured in the long range of the implantation profile.The coupled diffusion of high doses of P and low doses of Sb and B was studied. In the SIMS distributions enrichments of boron were observed. TEM measurements showed that they were correlating to a severe band of defects.SiP precipitates and large perfect dislocation half loops [mean radius (195±112) nm] were observed after annealing at 900°C for 120 min of implants with a dose of 5×10¹⁶ cm^–2 P. Because precipitation is occurring, simulation of phosphorus diffusion is at present not possible.

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Untersuchung von Hochkonzentrationseffekten von Sb und P in Silicium durch Kombination von SIMS und TEM

     

The synthesis of tetra-acrylamido-calix[4]arene capsules

Upper rim substituted tetra-acrylamido-calix[4]arenes have been synthesised using the palladium catalysed Heck reaction; the compounds display solvent dependent aggregation in solution to form dimeric capsules stabilised by only eight amide C=O-H-N hydrogen bonds and pi-pi interactions.     

A heterogeneous oscillator of the Belousov-Zhabotinskii-type in the bromate-malonic acid-cerium system induced by commercial ion-sensitive electrodes

In the title system we may induce oscillations under very special conditions near the borderline of the oscillating region by introducing ion-sensitive electrodes in the reaction mixture. The effect is caused by changing the conditions for oxygen transport via interface.

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Oscillations in the belousov-zhabotinskii system (BZR) catalysed by bis-bipyridine-silver complexes

A new catalytic ion couple [Ag(bipy)₂]⁺/[Ag(bipy)₂]²⁺ was found to catalyze the Belousov-Zhabotinskii reaction between bromate and malonic acid in sulfuric acid solution. Because of the insolubility of [Ag(bipy)₂]⁺ salts the reaction is not homogeneous. Oscillations could be observed to redox potential, the potentials of Ag⁺ and Br^? ion sensitive electrodes, and in light scattering caused by the periodic precipitation and dissolution of Ag^I complex.     

Modeling of two-phase flows with surface tension by finite pointset method (FPM)

A meshfree method for two-phase immiscible incompressible flows including surface tension is presented. The continuum surface force (CSF) model is used to include the surface tension force. The incompressible Navier–Stokes equation is considered as the mathematical model. Application of implicit projection method results in linear second-order partial differential equations for velocities and pressure. These equations are then solved by the finite pointset method (FPM), which is a meshfree and Lagrangian method. The fluid is represented as finite number of particles and the immiscible fluids are distinguished by the color of each particle. The interface is tracked automatically by advecting the color functions for each particle. Two test cases, Laplace's law and the Rayleigh–Taylor instability in 2D have been presented. The results are found to be consistent with the theoretical results.     

On the activation of valerolactam with triflic anhydride: the synthesis of omega-trifluorosulfonamido dipeptides using a transpeptidation reaction under mild conditions

The activation of valerolactam with triflic anhydride is studied in detail, initially producing an O-triflated lactam, which rearranges, following the addition of base at higher temperatures, to an N-triflated derivative. This reacts with a series of nucleophiles to produce esters and amides, which are formally dipeptides of omega-amino acids.     

The synthesis and conformation of oxygenated trianglimine macrocycles

The synthesis of series of D(2h) and C(2v) symmetric oxygenated aromatic dicarboxaldehydes, using dilithiation methodology, is described along with their reactivity in the [3+3] cyclocondensation reaction with (1R,2R)-diaminocyclohexane to give oxygenated trianglimine macrocycles. Macrocycles derived from C(2v) symmetric dialdehydes give macrocycles with a stereogenic aromatic plane with complete diastereocontrol, as a mixture of rotamers.     

Synthesis of calix[4]arene-based polycarboxylate ligands and their chemical immobilization onto controlled-pore glass

Three new calix[4]arene-based carboxylate ligands with an appended allyl function have been synthesized, chemically immobilized onto a controlled-pore glass (CPG), and the extracting ability of selected materials towards Sr²⁺ in solid-liquid extraction was examined. The calixarenes were characterized by elemental analysis, mass spectrometry, IR and NMR spectroscopy, and where appropriate by X-ray crystallography. Four functionalized CPGs were prepared by radical thiol addition of the corresponding 5-allylcalix[4]arenes to γ-mercaptopropyl-modified CPG. Analysis by ¹³C and ²⁹Si cross polarization/magic angle spinning (CP/MAS) NMR spectroscopy clearly showed the covalent fixation of the calix[4]arenes to CPG. The calix[4]arene phases were found to be stable up to 200 °C by simultaneous thermal analysis (STA). The extraction performance of the modified CPGs towards Sr²⁺ were found to be superior over the unmodified CPGs as demonstrated by radiotracing using the short-lived radio nuclide ⁸⁵Sr.     

Investigation of isomeric flavanol structures in black tea thearubigins using ultraperformance liquid chromatography coupled to hybrid quadrupole/ion mobility/time of flight mass spectrometry

Ultra performance liquid chromatography (UPLC) when coupled to ion mobility (IMS)/orthogonal acceleration time of flight mass spectrometry is a suitable technique for analyzing complex mixtures such as the black tea thearubigins. With the aid of this advanced instrumental analysis, we were able to separate and identify different isomeric components in the complex mixture which could previously not be differentiated by a conventional high performance liquid chromatography/tandem mass spectrometry. In this study, the difference between isomeric structures theasinensins, proanthocyanidins B‐type and rutin (quercetin‐3O‐rutinoside) were studied, and these are present abundantly in many botanical sources. The differentiation between these structures was accomplished according to their acquired mobility drift times differing from the traditional investigations in mass spectrometry, where calculation of theoretical collisional cross sections allowed assignment of the individual isomeric structures. The present work demonstrates UPLC–IMS‐MS as an efficient technology for isolating and separating isobaric and isomeric structures existing in complex mixtures discriminating between them according to their characteristic fragment ions and mobility drift times. Therefore, a rational assignment of isomeric structures in many phenolic secondary metabolites based on the ion mobility data might be useful in mass spectrometry‐based structure analysis in the future. Copyright © 2014 John Wiley & Sons, Ltd.