Measurement and analysis of earth's magnetic field based on low-magnetic field standards
The Cheongyang (CYG) observatory has been built to measure earth's magnetic field and to study prediction of earthquake and space weather. The equipments of the CYG observatory are a 3-axis fluxgate magnetometer, an overhauser effect proton magnetometer, a declination/inclination magnetometer and a data logger. A Cs-4He atomic magnetic resonance magnetometer was used to correct the measured data obtained by the proton magnetometer. All the measurement equipments were calibrated using magnetic field standard system maintained at KRISS. The Measurement results show a variation of the baselines less than 5 nT within one year, which is the most critical requirement criteria for joining the INTERMAGNET (International Real-time Magnetic Observatory Network).
Precise standard system for low dc magnetic field reproduction
A standard system for low magnetic fields has been developed at the Korea Research Institute of Standards and Science. The system consists of a precision solenoid, He–Cs atomic magnetic resonance magnetometer, and apparatus for three-axis compensation of the Earth’s magnetic field. The variations of the Earth’s magnetic field are automatically compensated within 0.1 nT/h by a Cs atomic magnetic resonance field controller. The solenoid reproduces a dc field that is uniform at better than 3×10−7 within ±2 cm around the center. The experimentally measured coil constant and temperature coefficient of the solenoid are 1.231 0596×10−3 T/A (25 °C) and 3.8×10−7/°C, respectively. The standard serves for the calibration of magnetometers and uniform field coils, and also supports experiments related to research in magnetic fields in the range of (0.02–1.2) mT with (2–10)×10−6 uncertainty.
The power of negativity : selected writings on the dialectic in Hegel and Marx
Part 1 The Philosophic Moment of Marxist-Humanism Part 2 Studies in Hegalian and Marxian Dialectics, 1956-63 Part 3 Theory and Practice at a Turning Point, 1964-71 Part 4 After Philosophy and Revolution: Hegel's Absolutes and Marx's Humanism, 1972-81 Part 5 The Changed World and the Need for Philosophic New Beginnings, 1982-87