First-principles study of ferroelectricity and isotope effects in H-bonded KH2PO4 crystals

By means of extensive first-principles calculations we studied the ferroelectric phase transition and the associated isotope effect in KH2PO4 (KDP)Comment: 16 pages, 10 figure

ВЫБОР ОБЩЕГО ИСТОЧНИКА СИГНАЛА ДЛЯ РЕГИОНАЛЬНОЙ СИСТЕМЫ СИНХРОНИЗАЦИИ ВРЕМЕНИ И ЧАСТОТЫ

In this article some results of comparative analysis of mostly used terrestrial radio signal sources are published. The aim of this observation is to utilize the sources signal as a common signal source in building Time and Frequency Synchronization System, according to common views algorithm. As a common sources digital TV broadcasting of (DVB-T2) signals and analog (Secam) TV signals were investigated. The correlation properties of this signals are investigated theoretically and practically. The list of equipment used in investigations: TV and FM signal receiver, digital oscilloscope, and software for calculation of inter- and autocorrelation functions and statistics. The correlational and statistical analysis proved that the signals of digital television format DVB-T2 can be effectively used as a general source for synchronization time and frequency scales by using common views algorithm.Анотаці

Isolation of an antimicrobial compound from Impatiens balsamina L. using bioassay-guided fractionation

By using brine shrimp (Artemia salina) lethality test-guided fractionation, a single bioactive compound (LC50=26 ppm) was isolated from the 95% ethanol extract of the dried aerial parts of Impatiens balsamina L. and subsequently identified as 2-methoxy-l,4-naphthoquinone (MNQ). The structure of MNQ was confirmed by UV, FT-IR, MS, and 1-and 2-D NMR spectroscopy. The antimicrobial activity of MNQ was evaluated using 12 bacterial and eight fungal strains. Five gram-positive and two gram-negative bacteria as well as all eight fungi (including multi-drug resistant strains) tested were highly sensitive to MNQ. A tea prepared according to traditional methods was found to contain sufficient MNQ to account for its antimicrobial properties. Copyrigh