Structural and optical properties of Cr doped AlN thin films before and after ions implantation

Thin films of Chromium (Cr) doped Aluminum Nitride (AlN) have been prepared by radio frequency magnetron sputtering technique at room temperature and pressure conditions in a Nitrogen (N) atmosphere. One of the samples was left as-deposited and the other was irradiated with proton at a fluence of 1x1014 ions/cm2 at a dose of 335 keV. The impact of ions doping on the structural and optical characteristics were investigated systematically. RBS and XRD were utilized to study the stoichiometry, thickness and structural information of the thin films respectively. FTIR was utilized to understand the bonding chemistry of the specimens. We concluded that the optical properties of the thin films have been changed selectively with irradiation leaving by structural unaltered.

Implementation of Molecular Visualization Program for Chemistry Learning

This study aims to investigate the implementation of molecular visualization programs for improving students’ understanding of concepts in chemical bonding. Chemistry learning in chemical bonding was conducted using molecular visualization program ACD/ChemSketch and Avogadro program. Several topics in chemical bonding include molecular geometry, polarity, bond angle, bond length, intermolecular forces and predicting boiling points. This study employs quasi-experimental research One Group Pretest – Posttest design. The subjects of this study were 46 students of undergraduate program in chemistry education department at Universitas Sanata Dharma. This study use test (pretest and pretest) and questionnaire to assess students’ perception of implementation of ACD/ChemSketch and Avogadro in chemistry learning. Implementation of ACD/ChemSketch and Avogadro in chemistry learning of chemical bonding gave an effect on students’ understanding based on paired t-test (sig < 0.05) and Kruskal-Wallis (sig < 0.05) test. The percentage of students is 45% with the medium N-gain category and 65% with the high N-gain category for ACD/ChemSketch program. It is 38.46% with the medium N-gain category and 61.54% with the high N-gain category for Avogadro program. Students show positive response to the implementation of ACD/ChemSketch and Avogadro program regarding their understanding, motivation and prospective skill for becoming teachers. Molecular visualization program helps the students to understand the chemical bonding topic.

Biocompatible chicken bone extracted dahllite/hydroxyapatite/collagen filler based polysulfone membrane for dialysis

In the current study, dahllite/hydroxyapatite/collagen filler extracted via calcination of wasted chicken bone was blended with PSf polymer to obtain highly biocompatible, and antifoulant hemodialysis membranes. FTIR and Raman spectroscopic analysis was done to obtain information about the bonding chemistry of the obtained filler. The intermolecular interaction that existed between dahllite/hydroxyapatite/collagen filler and pristine PSf was confirmed by Raman spectroscopic study. The PSf polymer exhibited a sponge-like structure owing to its high thickness and slow exchange with non-solvent in coagulation bath whilst the instantaneous de-mixing course produced finger-like capillaries in dahllite/hydroxyapatite/collagen filler based PSf membranes as exposed by SEM photographs. The presence of different wt. % of filler composition in the PSf matrix improved the mechanical strength as revealed by fatigue analysis. The hydrophilic character improved by 78% while leaching consistency adjusted to 0%–4%. Pure water permeation (PWP) flux improved by nine times. The pore profile improved with the addition of filler as revealed by hydrophilicity experiment, PWP flux, and SEM micrographs. Fouling evaluation results disclosed that filler based membranes showed 36% less adsorption of protein (BSA) solution together with more than 84% flux recovery ratio. The biocompatibility valuation analysis unveiled that membranes composed of filler showed extended prothrombin and thrombin coagulation times, reduced activation of fibrinogen mass, and less adhesion of plasma proteins in comparison with pristine PSf membrane. The adsorption capacity of fabricated membranes for urea and creatinine improved by 31% (in the case of urea) and 34% (in the case of creatinine) in contrast with pristine PSf membrane. The overall results showed that the M-3 membrane was optimized in terms of surface properties, protein adhesion, anticoagulation activity, and adsorption amount of urea and creatinine.

Unraveling the role of bonding chemistry in connecting electronic and thermal transport by machine learning

Electronic and thermal transport in materials originate from various forms of electron and ion interactions.

Arsenic adsorption on hematite facets: spectroscopy and DFT study

Surface bonding chemistry regulated by facet specific active sites is the intrinsic nature of facet-dependent arsenic adsorption on Fe2O3 facets.