A lanthanum-strontium manganite: HF absorption features in the 2–30 MHz frequency range

The RF magnetic response of a La_0.8Sr_0.2MnO₃ single crystal was studied in a frequency range from 2 to 30 MHz. The main contribution to the RF absorption in this range is related to the hysteresis losses. A new frequency-dependent anomaly in the HF absorption spectrum was observed and interpreted as being due to relaxation with a characteristic time above 10⁻⁷ s. The HF absorption measured as function of the field strength exhibits a sharp drop on approaching the saturation field, which makes the manganite studied a convenient material for the field and temperature sensors.     

In vitro activity of methanol extracts of plants used as spices against Mycobacterium tuberculosis and other bacteria

This study determined the phenolic composition of two thyme species (Lamiaceae), Origanum minutiflorum O. Schwarz and P.H. Davis and Thymbra spicata L. var. spicata, and assessed their antibacterial and antimycobacterial activities. “Kekik” is a collective term used in Turkey for plants that smell like thyme. O. minutiflorum, (locally “Sutculer kekigi”, endemic) and T. spicata var. spicata (locally “Karakekik”) are widely used in Turkey and are important export commodities.     

Magnetoresistance of nanobridges of lanthanum-strontium manganite

Nanobridges are fabricated from lanthanum-strontium anganite deposited on Si₃N₄ membranes perforated by a focused ion beam. The magnetoresistance is ≈9% in fields of ∼ kOe. Nonlinearity of the current-voltage characteristic of the bridges is observed, and it is found that the maximum of the resistance is shifted to lower temperatures from that of a control film sample of composition La_0.8Sr_0.2MnO₃. Pis’ma Zh. Tekh. Fiz. 25, 42–50 (May 26, 1999)     

单片机控制中频电源的新型起动法

介绍中频电源用单片机控制三桥臂的起动法,该法的优点:①可频繁起动,起动可基本无间隔;②可在全载全压下起动;③不受负载轻重的影响;④可适于更高频率的中频电源起动;⑤线路简单,成本低。     

Causal attributions of learning disabled children: Individual differences and their implications for persistence.

It has been shown that learning disabled (LD) children are likely to develop a maladaptive pattern of causal attributions. However, it is unclear whether LD children are more likely to differ from their peers in terms of a greater tendency to attribute their difficulties to insufficient ability or in terms of a greater tendency to blame external factors. The authors investigated this issue in 24 LD boys and 14 LD girls in Grades 3–5 and in 38 age-, sex-, race-, and IQ-matched normal controls. Ss were asked to complete scales assessing attributions for academic difficulties; 2 wks later, Ss were presented with a reading task for which persistence was measured. It was found that LD girls were significantly more likely than nondisabled girls to attribute their difficulties to insufficient ability, but girls did not differ in their tendency to attribute their difficulties to external factors. In contrast, LD boys were significantly more likely than nondisabled boys to attribute their difficulties to external factors, but they did not differ from nondisabled boys in their tendency to attribute their difficulties to insufficient ability. Although the tendency to blame one's ability was negatively related to reading task persistence, the tendency to attribute one's difficulties to external factors did not show this negative relation. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)