Electronic surface states of Cu(1 1 0) surface

Surface states are a unique and important class of quantum states that shave an important effect on the electronic properties of Cu(1 1 0) surface. The Cu(1 1 0) surface has been studied using ultraviolet photoemission spectroscopy (PES), inverse photoemission spectroscopy (IPES), and reflection anisotropy spectroscopy (RAS), and shows a resonance in the RAS spectra at 2.1 eV due to a transition between occupied and unoccupied surface states. The unoccupied surface state involved in the RAS transition at an energy of 1.7 eV at the point of the surface Brillouin zone has been investigated using IPES and the occupied surface state is seen in PES spectra at 0.45 eV below the Fermi level. The energy difference of the surface states, 2.15 eV, is a good match to the transition energy found in the RAS experiments.     

The zeta potential of PMMA in contact with electrolytes of various conditions: Theoretical and experimental investigation

Many unit operations required in microfluidics can be realised by electrokinetic phenomena. Electrokinetic phenomena are related to the presence of electrical surface charges of microfluidic substrates in contact with a liquid. As surface charges cannot be directly measured, the zeta potential is considered as the relevant parameter instead. PMMA is an attractive microfluidic substrate since micron‐sized features can be manufactured at low costs. However, the existence of PMMA surface charges is not well understood and the zeta potential data found in the literature show significant disagreement. In this article, we present a thorough investigation on the zeta potential of PMMA. We use computations of the potential distribution in the electrical double layer to predict the influence of various electrolyte parameters. The generated knowledge is compared to extensive experiments where we investigate the influence of ionic strength, pH, temperature and the nature of the electrolyte. Our findings imply that two different mechanisms influence the zeta potential depending on the pH value. We propose pure shielding in the acidic and neutral milieus while adsorption of co‐ions occurs along with shielding in the alkaline milieu.     

Nanosilica-bonded <Emphasis Type="Italic">N</Emphasis>-(propylsulfonyl) piperazine-<Emphasis Type="Italic">N</Emphasis>-sulfamic acid as recyclable catalyst for synthesis of 1,1′-(arylmethylene) diureas and 1,3,5-triazinane-2,4-dithiones

Nanosilica-bonded N-(propylsulfonyl) piperazine-N-sulfamic acid was easily prepared by functionalizing silica nanoparticles and characterized by thermogravimetric analysis, scanning electron microscopy, infrared (IR) spectroscopy, elemental analyses, and ion-exchange pH analysis. The catalytic activity of the functionalized nanosilica for preparation of 1,1′-(arylmethylene) diureas from reaction of aldehydes with urea derivatives was examined. The efficient effect of this catalyst led to preparation of 1,1′-(arylmethylene) diureas in high yield. The reaction of aldehydes with thiourea under the same reaction conditions afforded high yield of 1,3,5-triazinane-2,4-dithiones. Catalyst reusability, simple workup procedure, and short reaction time are other advantages of this protocol.     

Inverse photoemission spectroscopy of the unoccupied electronic structure of Na/Cu(110)

The unoccupied electronic states of Na thin films on a Cu(110) substrate have been measured by inverse photoemission spectroscopy (IPES). The IPES spectrum provides the intensity of the unoccupied states, which decreases with increasing Na coverage at off-normal incidence of the electron beam. The IPES spectra at 17 and 19 eV incident electron energies show a shift towards the Fermi level with increasing Na coverage for the peak at ∼7.8 eV.     

Optimization of fundamental parameters in routine production of 90Y-hydroxyapatite for radiosynovectomy

Hydroxyapatite was applied as a carrier adsorbing ⁹⁰Y³⁺ ions for ⁹⁰Y-HA colloid production. The radiopharmaceutical colloid was prepared by adding an acidic solution of ⁹⁰YCl₃ to HA suspension in saline solution. Effective parameters on labeling of ⁹⁰Y-HA were evaluated. Adsorption and cation-exchange properties were studied using inductively coupled plasma elemental analysis and N₂ adsorption–desorption isotherm method. Radionuclidic purity was over 99.9 %. Labeling yield and radiochemical purity were >99 %. Radiochemical purity was evaluated also in human albumin for 7 days at 37 °C. Biodistribution studies have shown complete retention of injected radioactivity at the administration site up to 72 h.     

Synthesis of phthalazine compounds using heterogeneous base catalyst based on silica nanoparticles obtained from rice husk

Research on Chemical Intermediates - In this study, the nanoparticles of amorphous silica were easily extracted from low-cost rice husk ash. They were functionalized with 3-(chloropropyl)...     

Microwave-induced high surface functionalization of multi-walled carbon nanotubes for long-term dispersion in water

Multi-walled carbon nanotubes (MWCNTs) were functionalized by monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) by a rapid microwave-assisted method. Surface functional groups and morphology of MWCNTs were analyzed by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy and transmission electron microscopy. The water dispersibility of samples was also measured over time and compared with that of MWCNT functionalized by ethylenediamine (EDA). Accordingly, the dispersibility was in the sequence MEA-MWCNTs > DEA-MWCNTs > TEA-MWCNTs > EDA-MWCNTs > pristine MWCNTs. The significant long-term dispersibility of MEA-MWCNTs was related to its exceptionally high surface functionalization (89.3 %) and lack of chemical bridging between adjacent MWCNTs. This strategy, along with the low-cost functionalizing agents, could pave the way for large-scale dispersion of CNTs in the polar solvents.