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Preparation of Ultrafine Particles of Metals and Metal Borides in Microemulsions
Published in Promod Kumar, K. L. Mittal, Handbook of Microemulsion Science and Technology, 2018
Based on the 13 C NMR and UV-Vis spectrophotometric results, the following models can be proposed for the four systems investigated (Fig. 8). Both Co(II) and Ni(II) atoms are retained at the interface in the different systems. More than one hexanol molecule enters the first coordination shell of Ni(II) ions. Co(II) interacts with one hexanol molecule in the CTAB-hexanol-water microemulsions, whereas both decanol and Triton X-100 molecules enter its first coordination shell. The Fe(III) ions are strongly hydrated in the inner water cores, and no hexanol molecules are able to replace the strongly held water molecules with this highly charged ion. Finally, the CTA+ ions interact indirectly only with the positively charged complexes.
Collective Effects
Published in Volker Ziemann, ®, 2019
How do you have to adjust Equation 12.1 to calculate the space-charge tune shift for highly charged ion beams, such Ar10+ or Pb82+?
An Introduction to Crystal Structures
Published in Elaine A. Moore, Lesley E. Smart, Solid State Chemistry, 2020
Elaine A. Moore, Lesley E. Smart
Several important trends in the sizes of ions can be noted from the data in Table 1.10: The radii of ions within a group of the periodic table, such as the alkali metals, increase with atomic number, Z: as you go down the group, there are more electrons and the outer ones are further from the nucleus. In a series of isoelectronic cations, such as Na+, Mg2+, and Al3+, the radii decrease rapidly with increasing positive charges. The number of electrons is constant, but the nuclear charge increases pulling the electrons in, and the radii decrease. For pairs of isoelectronic anions, for example, F− and O2−, the radii increase with increasing charges because the more highly charged ion has a smaller nuclear charge. For elements with more than one oxidation state, for example, Ti2+ and Ti3+, the radii decrease as the oxidation state increases: in this case, the nuclear charge stays the same but the number of electrons that it acts on decreases. As you move across the periodic table, for a series of similar ions, such as the first row transition metal divalent ions (M2+), there is an overall decrease in radii. This is due to an increase in the nuclear charge across the table because electrons in the same shell do not screen the nucleus from each other very well. A similar effect is seen for the M3+ ions of the lanthanoids and this is known as the lanthanoid contraction. For transition metals, the spin state affects the ionic radii. The crystal radii increase with an increase in the coordination number—see examples Cu+ and Zn2+ in Table 1.10.
In situ aerosol acidity measurements using a UV–Visible micro-spectrometer and its application to the ambient air
Published in Aerosol Science and Technology, 2020
Myoseon Jang, Shiqi Sun, Ryan Winslow, Sanghee Han, Zechen Yu
In ISORROPIA, the activity coefficients of all inorganic species are treated as 1, while E-AIM calculates the activity coefficient of H+. The activity coefficient of ionic species, which is related to ionic strength based on the Debye-Hűckel relationship (Christ 1965; Rindelaub et al. 2016), will deviate from 1 and may largely affect the prediction of [H+] in ammonia-rich aerosol at low humidity levels. The original Debye–Hückel limiting law was derived to determine the activity coefficient of an ion in a dilute solution of known ionic strength and thus, deviations in the actual [H+] from the theoretically calculated [H+] occur at high concentrations, particularly with highly charged ion electrolytes. In recent studies, the data obtained using the Raman technique was incorporated with Debye–Hückel theory to estimate the H+ activity coefficient, γ(H+). Given the ionic strength of the inorganic solutions, γ(H+) ranged from 0.684-0.737 in the study by Rindelaub et al. (2016) and from 0.68 − 0.75 in the study by Craig et al. (2017). Both studies showed a relatively narrow range of γ(H+). The C-RUV technique in this study cannot provide γ(H+), but deals with the non-ideal response of indicator in the acidic media (Equation (10)). The non-ideality of H+ that is related to the excess acidity term (i.e., in Eq. 10) ranges from 0.77 (RH = 0.1) to 0.95 (RH = 0.8) with our C-RUV method.
AISHa mechanical study and commissioning
Published in Radiation Effects and Defects in Solids, 2019
Francesco Noto, Giuseppe Costa, Luigi Celona, Francesco Chines, Santo Gammino, Ornella Leonardi, Salvatore Marletta, Giuseppe Torrisi
The new AISHa source is designed as an intermediate step between the second-generation ECRIS (unable to provide the requested current and/or brightness) and the third-generation ECRIS (1) (too complex and expensive). It is intended to be a multipurpose device, operating at 18 GHz, in order to achieve higher plasma densities. It should provide enough versatility for the future needs of the hadron therapy, including the ability to run at larger microwave power to produce different species and highly charged ion beams. At the same time, the electrical power to be installed for its operation will be kept below 50 kW. This demand also implies the simplification of all ancillary systems including an oven for metallic ion beams, which permits the production of new beams for hadron therapy and for other applications (2, 3).