scholarly journals Overcoming the limitations of cutoffs for defining atomic coordination in multicomponent systems

2017 ◽  
Vol 39 (12) ◽  
pp. 705-710 ◽  
Author(s):  
Jonathan Higham ◽  
Richard H. Henchman
Author(s):  
Dennis Maher ◽  
David Joy ◽  
Peggy Mochel

A variety of standard specimens is needed in order to systematically investigate the instrumentation, specimen, data reduction and quantitation variables in electron energy-loss spectroscopy (EELS). Pure single element specimens (e.g. various forms of carbon) have received considerable attention to date but certain elements of interest cannot be prepared directly as thin films. Since studies of the first and second row elements in two- or multicomponent systems will be of considerable importance in microanalysis using EELS, there is a need for convenient standards containing these species. For many investigations a standard should contain the desired element, or elements, homogeneously dispersed through a suitable matrix and at an accurately known concentration. These conditions may be met by the technique of implantation.Silicon was chosen as the host lattice since its principal ionization energies, EL23 = 98 eV and Ek = 1843 eV, are well removed from the K-edges of most elements of major interest such as boron (Ek = 188 eV), carbon (Ek = 283 eV), nitrogen (Ek = 400 eV) and oxygen (Ek = 532 eV).


1978 ◽  
Vol 43 (9) ◽  
pp. 2387-2394 ◽  
Author(s):  
Libor Červený ◽  
Dana Plecháčová ◽  
Vlastimil Růžička

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 475
Author(s):  
Guijin Liu ◽  
Junjian Li ◽  
Shiming Deng

Solid multicomponent systems (SMS) are gaining an increasingly important role in the pharmaceutical industry, to improve the physicochemical properties of active pharmaceutical ingredients (APIs). In recent years, various processes have been employed for SMS manufacturing. Control of the particle solid-state properties, such as size, morphology, and crystal form is required to optimize the SMS formulation. By utilizing the unique and tunable properties of supercritical fluids, supercritical anti-solvent (SAS) process holds great promise for the manipulation of the solid-state properties of APIs. The SAS techniques have been developed from batch to continuous mode. Their applications in SMS preparation are summarized in this review. Many pharmaceutical co-crystals and solid dispersions have been successfully produced via the SAS process, where the solid-state properties of APIs can be well designed by controlling the operating parameters. The underlying mechanisms on the manipulation of solid-state properties are discussed, with the help of on-line monitoring and computational techniques. With continuous researching, SAS process will give a large contribution to the scalable and continuous manufacturing of desired SMS in the near future.


Author(s):  
Jordan J. Romvary ◽  
Giulio Ferro ◽  
Rabab Haider ◽  
Anuradha M. Annaswamy

2020 ◽  
Vol 153 (11) ◽  
pp. 114302
Author(s):  
Diletta Meroni ◽  
Angelo Monguzzi ◽  
Francesco Meinardi

2016 ◽  
Vol 848 ◽  
pp. 688-695
Author(s):  
Xiao Hong Xiao ◽  
Shi Chun Li

The bonds structure, atomic coordination situation and local cluster structure in SrBi2Ta2O9 were analyzed by means of the Atomic Environment Calculation (AEC), and then the SrBi2Ta2O9 crystal was decomposed into 20 pseudo-binary crystals with the crystal decomposition method. The chemical bonds properties, such as effective valence electron density and iconicity of the individual bond were calculated by the dielectric chemical bonds theory. And the correlation between chemical bonds properties and spontaneous polarization of the bismuth layered ferroelectrics was established. Finally, the spontaneous polarization in ferroelectric SrBi2Ta2O9 and other relevant ferroelectrics were calculated, which are in good agreement with the experimental values and other theoretical calculated values.


2016 ◽  
Vol 70 (12) ◽  
Author(s):  
Leonid Serafimov ◽  
Anastasia Frolkova

AbstractA method for the determination of vapor–liquid phase diagram structure of five-component systems based on the analysis of types and Poincare indexes of singular points of the geometric scan and full structure of the concentration simplex is proposed. Validity of the proposed method was demonstrated by vapor–liquid equilibrium modeling in five-component mixtures: ethanol + water + toluene + butanol + chlorbenzene and acetone + chloroform + ethanol + cyclohexane + water.


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