Surface elemental and structural analysis of ancient Indian punch-marked coins (600 to 200 BCE): insights into metallurgy and economic practices.

Punch-marked coins (PMCs) are the oldest coins in India and among the most widely circulated globally, often found in hoards that highlight their extensive use. This study utilizes X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to analyze the surface elemental composition and chemical properties of nine series (S-0 to S-VIII) of Janapada (S-0) and imperial PMCs (S-1 to S-VIII) dating from 600 to 200 BCE, housed in the Numismatic Society of India at BHU, Varanasi, based on the Gupta-Hardakar classification related to the PMCs. XRD results reveal four prominent diffraction peaks corresponding to metallic silver (Ag) in the face-centred cubic (fcc) phase, with a slight variation in d-spacing (∼ 0.

Photophysics of soret-excited tin(IV) porphyrins in solution.

The photophysics of low-chlorin tin(IV) tetraphenylporphyrin dihydroxide, a core building block for axially substituted supramolecular tin porphyrin constructs, has been studied in a variety of hydrogen-bonding, nonpolar, and aprotic polar solvents using steady-state, nanosecond, and femtosecond time-resolved emission, and femtosecond time-resolved absorption methods. In hydrogen-bonding solvents the metalloporphyrin exists as solvated monomers, and its Soret-excited S2 state in these solvents exhibits the expected linear energy gap law relationship with first-order population decay times in the 0.8 to 1.

Controlled synthesis, characterization, and application of iron oxide nanoparticles for oral delivery of insulin.

Impurity-free, controlled synthesis of iron oxide nanoparticle, in ultrapure water and chitosan, using laser ablation technique and its application for type II diabetes management through oral delivery of insulin-loaded iron oxide-chitosan nanocomposite is presented. The purity of the nanoparticle is monitored by laser-induced breakdown spectroscopy technique. The synthesized iron oxide nanoparticle was characterized by UV/Vis absorption spectroscopy, and morphological study was performed by scanning electron microscope.

Upconversion based tunable white-light generation in Ln:Y(2)O(3) nanocrystalline phosphor (Ln = Tm/Er/Yb).

We report the generation of efficient white light based on upconversion (UC) in Tm(3+)/Er(3+)/Yb(3+):Y(2)O(3) nanocrystalline phosphor synthesized by simple and cost effective solution combustion technique on 976 nm laser excitation. The calculated color coordinates (using 1931 CIE standard) for samples annealed at different temperatures vary from (0.16, 0.

Intense green and red upconversion emissions from Ho(3+) in presence of Yb(3+) in Li:TeO2 glass.

Weak visible emission is observed at 545 nm and 660 nm on 976 nm excitation of Ho(3+) ions doped in tellurite glass. Addition of ytterbium to the doped glass causes a large increase in intensity of the green and the red emissions. In addition to these two new emissions of Ho(3+) one in the blue and the other in the NIR region are also observed.

Judd-Ofelt analysis of Tm and energy transfer studies between Tm and Er codoped in lithium tellurite network.

Optical properties of Tm(3+) and Er(3+) and Tm(3+)+Er(3+) codoped tellurite glass have been studied using different wavelengths from a Ti-Sapphire laser as excitation source. The energy transfer from one rare earth to other on excitation with different wavelengths has been studied. The Judd-Ofelt theory has been used to calculate various optical parameters suitable for laser oscillation.