The development of novel methods, scientific devices and means for measuring magnetic fields generated by ultra-low current is among promising directions in the development of medical equipment and instruments for geodetic surveys and space exploration. The present work is to develop a small sensor capable of detecting weak magnetic fields, which sources are biocurrents, radiation of far space objects and slight fluctuations of the geomagnetic field. Scientists estimate the strength of such magnetic fields as deciles of nanotesla. The key requirements for the sensors of ultra-low magnetic field are: resolution, noise level in the measurement channel, temperature stability, linearity and repeatability of the characteristics from one produced item to another. The aforementioned characteristics can be achieved by using planar technologies and microelectromechanical systems (MEMS) in such advanced sensors.The work describes a complete R&D cycle, from creating the computer model of the sensor under study to manufacturing of a working prototype. To assess the effect of the geometry and material properties, the Jiles–Atherton model is implemented which, unlike the majority of the models used, allows considering the non-linearity of the core, its hysteresis properties and influence of residual magnetization.The dimensions of the developed sensor are 40×20×5 mm, while the technology allows its further diminishment. The sensor has demonstrated the linearity of its properties in the range of magnetic field strength from 0.1 nT to 50 µT for a rms current of excitation of 1.25 mA at a frequency of 30 kHz. The average sensitivity for the second harmonic is 54 µV/nT.
Дана оценка динамики двух ледников Алтая-Томич (Катунский хребет) и Водопадный (Северо-Чуйский хребет) за период инструментальных наблюдений. Данные об изменении площади и объёма ледников с 1960-70-х годов до настоящего времени получены на основе архивных материалов: топографических карт, космических и радиолокационных съёмок, а также полевых исследований, выполненных авторами на этих ледниках в 2009-2011 гг. За исследуемый период площадь ледников сократилась на 19-25%, а объём-на 30-45%. Максимальная потеря льда произошла с середины 1990-х годов до настоящего времени. Установлена связь между интенсивностью ежегодной потери льда и средней летней температурой в ледниковой зоне Алтая. Estimates of dynamics of two Altai glaciers Tomich (Katun Ridge) and Vodopadny (North Chuisky Ridge) for the whole period of instrumental observations are shown in the paper. Data on changes of the glaciers' areas and volumes were obtained from the topographic maps, satellite images and author's field researches performed in 2009-2011. During the period of observations (1952-2012), the glacier areas decreased by 19-25%, and the volumes by 34-45%, and the maximum loss of ice took place since the mid-1990s up to present time. The annual rate of the ice loss has been linked to the average summer air temperature over the glacier area of Altai.
The paper deals with the fluxgate transducer intended for navigation and attitude control systems for moving vehicles. The finite element modeling of the half-sine and sawtooth pulse loads of various durations is performed for the proposed fluxgate configuration with regard to the properties of materials used.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.