There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Fundamentals and advances in magnesium alloy corrosion

Spinels with the formula of AB2O4 (where A and B are metal ions) and the properties of magnetism, optics, electricity, and catalysis have taken significant roles in applications of data storage, biotechnology, electronics, laser, sensor, conversion reaction, and energy storage/conversion, which largely depend on their precise structures and compositions. In this review, various spinels with controlled preparations and their applications in oxygen reduction/evolution reaction (ORR/OER) and beyond are summarized. First, the composition and structure of spinels are introduced. Then, recent advances in the preparation of spinels with solid-, solution-, and vapor-phase methods are summarized, and new methods are particularly highlighted. The physicochemical characteristics of spinels such as their compositions, structures, morphologies, defects, and substrates have been rationally regulated through various approaches. This regulation can yield spinels with improved ORR/OER catalytic activities, which can furth...

Spinels: Controlled Preparation, Oxygen Reduction/Evolution Reaction Application, and Beyond

Metal oxide nanoparticles are used in a wide range of commercial products, leading to an increased interest in the behavior of these materials in the aquatic environment. The current study focuses on the stability of some of the smallest ZnO nanomaterials, 4 ± 1 nm in diameter nanoparticles, in aqueous solutions as a function of pH and ionic strength as well as upon the adsorption of humic acid. Measurements of nanoparticle aggregation due to attractive particle−particle interactions show that ionic strength, pH, and adsorption of humic acid affect the aggregation of ZnO nanoparticles in aqueous solutions, which are consistent with the trends expected from Derjaguin−Landau−Verwey−Overbeek (DLVO) theory. Measurements of nanoparticle dissolution at both low and high pH show that zinc ions can be released into the aqueous phase and that humic acid under certain, but not all, conditions can increase Zn2+(aq) concentrations. Comparison of the dissolution of ZnO nanoparticles of different nanoparticle diameters...

Aggregation and Dissolution of 4 nm ZnO Nanoparticles in Aqueous Environments: Influence of pH, Ionic Strength, Size, and Adsorption of Humic Acid

Recovery of vanadium oxide from the steelmaking slag is of great interest for Swedish steel producers and technique for assessing the oxidation state of vanadium is crucial in optimization of the vanadium recovery. There is a large spread in the reported values of the published V2p3/2 binding energy values for various oxidation states of vanadium. Therefore extensive analysis of vanadium oxide standards was performed aiming to obtain reliable data as well as improved methods for preparation of representative oxide standards. Powdered oxide standards of V2O5, VO2, V2O3 and VO of purity better than 99% were chosen. In as-received state all of the standards are covered by a thin layer of vanadium pentoxide that does not allow accurate evaluation of XPS spectra for vanadium oxides in lower oxidation states. Therefore different methods for obtaining of representative surface for vanadium oxide standards were tested. The experimental results show high-sensitivity of vanadium oxide standards to argon ion etching. Hence, a method to obtain representative surface chemical compositions of standards by special heat-treatment is proposed. Such approach was developed using preparation chamber (furnace) attached to the XPS instrument. The annealing was performed in vacuum at defined temperatures from 400 to 900oC for 4-24 hours; the annealing parameters were selected based on thermodynamic equilibrium data for vanadium oxides. Experimental fitting parameters (peak position E and full width of half maximum of the peak FWHM) for vanadium V2p3/2 and oxygen O1s peaks are thus obtained for stoichiometric vanadium oxides.

Stoichiometric vanadium oxides studied by XPS

https://www.researchgate.net/profile/Alfonso_Perez/publication/280568894_Selective_band_gap_manipulation_of_graphene_oxide_by_its_reduction_with_mild_reagents/links/55ba627a08aec0e5f43e9c48.pdf

Selective band gap manipulation of graphene oxide by its reduction with mild reagents

Surface composition of the steel powders pre-alloyed with manganese

http://publications.lib.chalmers.se/records/fulltext/209426/local_209426.pdf

Influence of temperature on the atmospheric corrosion of the Mg-Al alloy AM50

http://publications.lib.chalmers.se/records/fulltext/241311/local_241311.pdf

Lars Nyborg

Papers

Stoichiometric vanadium oxides studied by XPS

Selective band gap manipulation of graphene oxide by its reduction with mild reagents

Surface composition of the steel powders pre-alloyed with manganese

Influence of temperature on the atmospheric corrosion of the Mg-Al alloy AM50

Influence of Coolant Flow Rate on Tool Life and Wear Development in Cryogenic and Wet Milling of Ti-6Al-4V