The impact of the natural sciences on archaeology

This article reviews some of the applications of physics to the solution of archaeological problems. The use of magnetic, resistivity and electromagnetic surveying techniques for the location of buried features is described. Various methods of age determination are outlined while the problems associated with radiocarbon dating of organic material and thermoluminescent dating of pottery are discussed in detail. The techniques, including petrological examination, chemical analysis and isotopic analysis, employed in the physical examination of archaeological artefacts are described. Examples of the application of these techniques in establishing the source of the raw materials used in pottery, metal and stone implements and in elucidating the techniques of manufacture of pottery and metal objects are also given.     

Analysis of the procedure for filling cells for a quantum frequency standard based on Rb87 vapors

The effect of various physical processes on the replicability of cells for a quantum frequency standard based on Rb⁸⁷ was investigated. A replication accuracy of 2 · 10^–11 was obtained experimentally for the frequency of the spectral line of the gas cell.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 15, No. 1, pp. 27–32, January, 1972.     

Natural fluctuations in a quartz crystal oscillator with automatic gain control

A method is developed for calculation of natural fluctuations in oscillators with automatic gain control (AGC). As an example, a three-terminal capacitive transistor crystal oscillator is considered. It is shown that the AGC system permits stabilization of the amplitude and frequency of the oscillator output signal.     

Phenolic compounds,essential oil composition,and antioxidant activity of Angelica purpurascens (Avé-Lall.) Gill

In this study, methanol extracts (MEs) and essential oil (EO) of Angelica purpurascens (Avé-Lall.) Gill obtained from different parts (root, stem, leaf, and seed) were evaluated in terms of antioxidant activity, total phenolics, compositions of phenolic compound, and essential oil with the methods of 2,2-azino-bis(3ethylbenzo-thiazoline-6-sulfonic acid (ABTS•⁺), 2,2-diphenyl-1-picrylhydrazil (DPPH•) radical scavenging activities, and ferric reducing/antioxidant power (FRAP), the Folin–Ciocalteu, liquid chromatography−tandem mass spectrometry (LC−MS/MS), and gas chromatography-mass spectrometry (GC−MS), respectively. The root extract of A. purpurascens exhibited the highest ABTS•⁺, DPPH•, and FRAP activities (IC₅₀: 0.05 ± 0.0001 mg/mL, IC₅₀: 0.06 ± 0.002 mg/mL, 821.04 ± 15.96 µM TEAC (Trolox equivalent antioxidant capacity), respectively). Moreover, EO of A. purpurascens root displayed DPPH• scavenging activity (IC₅₀: 2.95 ± 0.084 mg/mL). The root extract had the highest total phenolic content (438.75 ± 16.39 GAE (gallic acid equivalent), µg/mL)). Twenty compounds were identified by LC−MS/MS. The most abundant phenolics were ferulic acid (244.39 ± 15.64 μg/g extract), benzoic acid (138.18 ± 8.84 μg/g extract), oleuropein (78.04 ± 4.99 μg/g extract), and rutin (31.21 ± 2.00 μg/g extract) in seed, stem, root, and leaf extracts, respectively. According to the GC−MS analysis, the major components were determined as α-bisabolol (22.93%), cubebol (14.39%), α-pinene (11.63%), and α-limonene (9.41%) among 29 compounds. Consequently, the MEs and EO of A. purpurascens can be used as a natural antioxidant source.     

Transition Metal Ion-binding Properties of a 14-Membered N2O2S2- Macrobicyclic Ligand

The selective liquid–liquid extraction of various transition metal cations from the aqueous phase to the organic phase was carried out using a 14-membered N₂O₂S₂-macrobicycle. Metal picrates such as Pb²⁺, Co²⁺, Zn²⁺, Ni²⁺,Cu²⁺ and Cd²⁺ were used in this extraction studies. It was found that the ligand showed moderate selectivity towards Pb²⁺ only among the other metals. The extraction constant (log K _ex) was determined to be 13.8 for Pb²⁺ complex.     

Novel experimental arrangement developed for direct fullerene analysis by electrospray time-of-flight mass spectrometry

A novel electrospray setup was found effective for direct analysis of fullerene solutions by electrospray (ES) mass spectrometry. The electrospray capillary needle used for the analysis is equipped with a thin metal (copper, platinum or stainless steel) wire installed inside the capillary. The wire tip protrudes slightly from the capillary end. In this configuration the high electrical field formed by the wire tip stimulates a specific electrospray mode with a fine spray originating from the tip. The correlation of the acquired mass spectra with the magnified view of the spray at the capillary tip was investigated. The effective formation of fullerene ions in both negative and positive ion modes was observed in mass spectra only in the specific case of the electrospray originating from the wire tip. The fullerene di-anions observed in the negative ES mass spectra provide evidence for the electrochemical nature of this process occurring at the ES capillary tip. Observation of fullerene ions in mass spectra obtained using the suggested electrospray arrangement is assumed to be a consequence of the fine spray originating from the sharp metal wire tip. In this case the liquid/metal interface is near the Taylor cone apex.