RESUMO
Optically pumped magnetometers can provide functionality for bio-magnetic field detection and mapping. This has attracted widespread attention from researchers in the biomedical science field. Magnetocardiography has been proven to be an effective method for examining heart disease. Notably, vector magnetocardiography obtains more spatial information than the conventional method by only taking a component that is perpendicular to the chest surface. In this work, a spin-exchange-relaxation-free (SERF) magnetometer with a compact size of 14 mm × 25 mm × 90 mm was developed. The device has a high sensitivity of 25 fT/ Hz. Meanwhile, in the multichannel working mode, synchronous sensor manipulation and data acquisition can be achieved through our control software without additional data acquisition boards. Since a typical SERF magnetometer only responds to dual-axis magnetic fields, two sensors are orthogonally arranged to form a vector detection channel. Our system consists of seven channels and allows 7 × 9 vector MCG mapping by scanning. High-quality heart vector signals are measured, and P peak, QRS peak, and T peak can be distinguished clearly. To better demonstrate the vectorial information, a vector scatter plot form is also provided. Through a basic bio-electric current model, it demonstrates that triaxial MCG measurements capture a richer spatial current information than traditional uniaxial MCG, offering substantial diagnostic potential for heart diseases and shedding more light on the inversion of cardiac issues.
RESUMO
Nowadays development of industry and traffic are the main contributor to city air pollution in the city of GuangZhou, China. Conventional methods for investigating atmosphere potentially harmful element pollution based on sampling and chemical analysis are time and labor consuming and relatively expensive. Reflectance spectroscopy within the visible-near-infrared region of vegetation in city has been widely used to predict atmosphere constituents due to its rapidity, convenience and accuracy. The objective of this study was to examine the possibility of using leaves reflectance spectra of vegetation as a rapid method to simultaneously assess pollutant (S, Cd, Cu, Hg, Pb, XCl, XF) in the atmosphere of the Guangzhou area. This article has studied the spectral features of polluted leaf surface of Ficus microcarpa in 1985 and 1998. According to the analysis, comprehensive assessment for the change of atmospheric condition and degrees of pollution were given. This conclusion was confirmed by the monitored data got from chemical analysis. Future study with real remote sensing data and field measurements were strongly recommended.