ABSTRACT We present the binary residual map (BRM) as a convenient, qualitative, information‐rich representation of multiple fits or analyses in data analysis. The BRM focuses on and retains the signs of the residuals, not necessarily their magnitudes, where these residuals are color coded with one color selected for positive residuals and another for negative residuals. To form a BRM, color‐coded residuals from multiple fits obtained with multiple fit parameter values are stacked/displayed as a function of the fit parameter value. Importantly, when a series of residual values in a fit are either all positive or all negative, the color‐coded residuals appear as a colored block or run. In general, longer runs indicate poorer fitting. The BRM contains an enormous amount of information in a small space. Accordingly, it can be used to quickly identify where the values of a fit produce better or worse fits. In a qualitative way, it guides the selection of fit parameters. Gradient BRMs that take into account the magnitude of the residuals can also be created. We demonstrate the creation of BRMs and/or gradient BRMs from the Fourier denoising of X‐ray photoelectron spectroscopy (XPS) spectra using a Gauss–Hermite (GH) filter function positioned at a series of different cutoff frequencies in reciprocal space, fits to carbon Auger XPS spectra with polynomials of different orders, and XPS peak fitting. BRMs should also be useful for evaluating the fits of other types of data (not just XPS data).
ABSTRACT Inverse gas chromatography (IGC) was employed to investigate how the presence of hemicellulose influences surface properties and adsorption behavior of cellulose nanofibers. Two samples prepared under equivalent processing conditions were compared: cellulose rich nanofibers (CNFs) and nanofibers containing approximately 20 wt% hemicellulose (CNFp). Adsorption measurements were performed at infinite dilution using nonpolar and polar molecular probes at 40°C, 50°C, and 60°C. Dispersive and specific adsorption interactions were evaluated using the Hamieh approach, whereas the conventional Schultz method was applied as a complementary analysis. Although London dispersive interactions dominated the total adsorption free energy of all polar probes, the specific contribution revealed a temperature dependent contrast between the materials: CNFp exhibited higher magnitudes of specific adsorption free energy than CNFs for four of the seven polar probes at 40°C and for all seven at 50°C and 60°C, despite its less exothermic specific adsorption enthalpies. Both surfaces exhibited amphoteric behavior, with a greater affinity for the Lewis basic THF probe. The sensitivity analysis indicated that the absolute dispersive surface energy estimates were more dependent on the adopted molecular descriptors than the calculated specific adsorption free energies. Together with FTIR, zeta potential, and water contact angle measurements, the IGC results support the proposed hypothesis that the presence of hemicellulose modifies the surface adsorption environment of cellulose nanofibers, favoring the persistence of specific polar interactions, including possible contributions from hydrogen bonds, at elevated temperatures. These findings highlight the potential of tailoring nanofiber composition to control interfacial interactions in materials containing cellulose.
ABSTRACT Aluminium–air batteries are low cost and have a high theoretical capacity, but the discharge efficiency and metal utilisation are restricted by the self‐corrosion of aluminium‐anode in alkaline electrolyte. In this study, two Meldrum's acid derivatives, thiophenecarboxaldehyde Meldrum's acid (THMA) and p ‐tolualdehyde Meldrum's acid (TOMA), were synthesised and evaluated as corrosion inhibitors for aluminium in 3 M KOH solution. The structural compounds were validated using ATR‐FTIR, NMR and elemental analysis. At room temperature, after 6 h of immersion in 3 M KOH and various concentrations of inhibitors, the results revealed that inhibition efficiency increased with increasing inhibitor concentration, with maximum efficiency of 65.77% (THMA) and 63.99% (TOMA) at 2.5 mM. Weight‐loss measurements were conducted in triplicate ( n = 3), and the corrosion rate was reported as 0.00588 ± 0.00053 g cm −2 h −1 (TOMA) and 0.00559 ± 0.00016 (THMA; mean ± SD). THMA and TOMA were best described by the Freundlich and Langmuir isotherms, respectively, while Gibbs free‐energy values suggested mixed physical and chemical adsorption on the aluminium surface. Surface analyses demonstrated the formation of a protective layer that significantly reduced aluminium surface damage in alkaline media. RSM optimisation revealed optimal conditions at an inhibitor concentration of 0.51 mM, KOH concentration of 0.61 M and immersion time of 2.81 h, yielding predicted inhibition efficiencies of 81.90% (THMA) and 74.00% (TOMA). Pearson correlation analysis showed that immersion time is the most influential factor affecting inhibition efficiency, while machine learning modelling indicated that the random forest algorithm provided the most reliable prediction performance.
ABSTRACT Blue phosphorus is the metastable hexagonal allotrope of two‐dimensional phosphorus and a wide‐gap semiconductor of growing interest for post‐graphene electronics. Its surface composition at the atomic‐layer level remains uncharacterized, however, because experimental low‐energy ion scattering (LEIS) on the nm‐scale samples currently available is not yet feasible. We present a comprehensive azimuth‐resolved multi‐ion BCA survey of LEIS from free‐standing single‐layer blueP, designed from the outset as a practical protocol for the experimental campaigns that will follow once larger‐area samples become available. The simulations combine NLH interatomic potentials, auto‐calibrated Lindhard–Scharff electronic stopping, temperature‐dependent thermal vibrations, and Hagstrum ion‐survival; we check the kinematic and detector‐bookkeeping consistency of the framework against Si(100)/He + , where the simulated peak matches the analytical prediction to within 0.1% of the incident energy. The azimuthal scan of He + reproduces the sixfold periodicity that the P‐3m1 symmetry of the bilayer requires. The quantitative content of the scan (peak yields of 22.8% at the zigzag direction and 15.3% at the armchair direction against a blocked‐azimuth background below 0.4%, Wilson 95% upper bound at N = 900) gives a peak‐to‐trough contrast in excess of 50 that distinguishes blueP from orthorhombic black phosphorus and provides the reference numbers against which an experimental scan can be tested. Three further findings—kinematic discrimination among the noble gases (with Ar + kinematically forbidden beyond θ max = 50.83°), a ratiometric He + /Ne + vacancy probe, and an anti‐channelling temperature dependence—together specify a practical experimental protocol.
ABSTRACT Amorphous silicon thin films have attracted considerable attention for photovoltaic applications owing to their low material consumption and compatibility with low‐temperature fabrication processes. In this work, amorphous silicon films were deposited on indium tin oxide substrates by radio‐frequency magnetron sputtering. The structural, optical, and electrical properties of the films were systematically investigated using atomic force microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, photoluminescence (PL) spectroscopy, and current density–voltage measurements. The results indicate that the deposited films possess an amorphous structure. With increasing sputtering time, both the surface roughness and longitudinal resistance increase gradually, which is mainly attributed to the increase in film thickness. The PL spectra exhibit broad emission bands that are associated with Si 4+ ‐related oxide layers, while the observed redshift can be attributed to the formation of Si 2+ states resulting from incomplete oxidation of Si 0 . These findings provide valuable insights into the structural and electrical characteristics of amorphous silicon films and may contribute to the optimization of thin‐film silicon materials for photovoltaic and optoelectronic applications.
