Shields

About: Shields is a research topic. Over the lifetime, 1456 publications have been published within this topic receiving 10896 citations.

A new approach to calculate the shielding factor of magnetic shields comprising nonlinear ferromagnetic materials under arbitrary disturbances

Abstract: To enable the realization of ultra-low magnetic fields for scientific and technological research, magnetic shielding is required to create a space with low residual magnetic field and high shielding factors. The shielding factors of magnetic shields are due to nonlinear material properties, the geometry and structure of the shields, and the external magnetic fields. Magnetic shielding is used in environments full of random realistic disturbances, resulting in an arbitrary and random external magnetic field, and in this case, the shielding effect is hard to define simply by the shielding factors. A new method to simulate and predict a dynamic internal space magnetic field wave is proposed based on the Finite Element method (FEM) combined with the Jiles-Atherton (JA) model. By simulating the hysteresis behavior of the magnetic shields and establishing a dynamic model, the new method can simulate dynamic magnetic field changes inside magnetic shields as long as the external disturbances are known. The shielding factors under an AC external field with a sine wave and certain frequencies are calculated to validate the feasibility of the new method. A real-time wave of internal magnetic flux density under an AC triangular wave external field is simulated directly with the new method versus a method that splits the triangular wave into several sine waves by a Fourier transform, divides the shielding factors, and then adds the quotients together. Moreover, real-time internal waves under some arbitrary fields are measured. Experimental internal magnetic flux density waves of a 4-layer magnetically shielded room (MSR) at the Harbin Institute of Technology (HIT) fit the simulated results well, taking experimental errors into account.

Sputtering device and formation of coating using this device

Abstract: PROBLEM TO BE SOLVED: To prolong the interval of maintenance by heating and controlling a sticking preventing shield and a target shield. SOLUTION: In this device, a substrate 3 is heated and controlled, e.g. to >=200 deg.C by a heating heater 5, and simultaneously, a target shield 6 and a sticking preventing shield 7 are heated by a heater 8. The temps. of the shields at this time are controlled by a temp. controlling unit 10 so as to be regulated to the ones increased by radiation from plasma and the heater 5 in the process of coating formation or above. After the temps. are stabilized, electric power is fed from a power source 11, and sputtering is executed. After the coating is formed to a required coating thickness, the feed of the electric power is stopped, but, the heating control is continued as it is till the following coating forming stage. In this way, the shields are always heated, by which the temp. changes of the shields are eliminated, and the peeling of the stuck coating with different expansion coefficients is prevented to suppress the increase of particles, so that the exchanging period of the shields can be prolonged.

Temperature control apparatus for electrode type boilers

Abstract: 668,661. Fluid-pressure servomotor-control systems. G.W.B. ELECTRIC FURNACES, Ltd. Nov. 15, 1950 [Nov. 28, 1949], No. 30489/49. Class 135 [Also in Groups XI and XXXV] In an electrical type water boiler the electrodes 4 are provided with insulating shields 10 and are carried by a hydraulic piston 7, movement of the shields being under the control of an electrically operated pump 13 and electrically operated valve 15, the pump and valve being operated by a thermostat 17 to maintain the water temperature within predetermined limits. The thermostat 17 comprises a "low" contact and "high" contact, the closure of the "low" contact causing operation of the pump 13 to raise the shields, exposing more of the electrodes and thereby increasing the temperature of the water, and closure of the "high" contact causing the valve 15 to be opened so that the shields are allowed to fall and the temperature of the water is decreased. In the event of failure of the control apparatus, or should the temperature of the water rise excessively, a second thermostat 24 is adapted to operate a relay 25 to switch off the main supply to the electrodes.

Magnetic vacuum systems and devices for use with superconducting-based computing systems

Abstract: Magnetic shields and magnetic shielding systems are described. The excessive spatial demands of known mu-metal/cryoperm and superconducting shielding systems are reduced by a new multi-piece shield construction approach. A complete magnetic shielding system for use with superconducting-based computing systems, such as superconducting quantum computing systems, is also described. This complete system may include mu-metal/cryoperm shields and superconducting shields using either compensatory magnetic fields, expulsion by temperature gradients, or a combination of the two.