1. A method for MR imaging of a patient comprising providing an MR magnet to generate a magnetic field to be applied to the patient;
generating an RF pulse in the magnetic field to be applied to the patient such that the imaged part of the patient generates an MR signal in response to the magnetic field and the RF pulse applied thereto;
acquiring MR signals from the part of the patient in a receive stage;
carrying out signal processing on the acquired signals by which an image is generated;
providing a plurality of surface electrodes attached to the skin of the patient at spaced positions on the skin for communicating electrical currents through the skin;
the surface electrodes each including a communication conductor for carrying the current;
wherein each of the surface electrodes comprises a conductive layer having a bottom surface attached to the skin, the conductive layer having a conductive location thereon connected to the communication conductor;
and reducing artifacts in the generated image by dividing the conductive layer into separate side by side sections where the separation into the side by side sections is arranged to reduce eddy currents which are induced in the surface electrodes when they are exposed to variations in the magnetic field and to RF pulses;
the side by side sections being divided so that all are connected through the layer to the conductive location to allow the current to be connected to the communication conductor.
2. The method according to claim 1 wherein the conductive layer is formed of a non-ferromagnetic conductive metal.
3. The method according to claim 1 wherein the conductive layer is formed of silver-silver chloride.
4. The method according to claim 1 wherein the sections are formed in the conductive layer by slits dividing each section from the next so that the eddy currents cannot bridge the slits.
5. The method according to claim 1 wherein the slits extend to the edge of the conductive layer.
6. The method according to claim 1 wherein the slits extend to a position spaced from the edge of the conductive layer.
7. The method according to claim 6 wherein the conductive location is arranged along one edge of the conductive layer and the layer is divided into sections generally transverse to the edge.
8. The method according to claim 1 wherein the conductive layer includes an adhesive layer on the bottom surface for adhesive attachment of the layer to the skin.
9. The method according to claim 1 wherein the adhesive layer forms an integral layer bridging the slits.
10. The method according to claim 1 wherein the conductive location is arranged in a central region of the layer and the conductive layer is divided into sections extending generally outwardly from the central region.
11. The method according to claim 1 wherein the sections extend generally radially from the central region.
12. The method according to claim 1 wherein the sections include at least parts which extend generally angularly around the central region.
13. The method according to claim 1 wherein there is provided a quick connection coupler so as to allow removal of the communication conductor during the MR imaging.
14. The method according to claim 13 wherein the quick connection coupler is arranged in the communication conductor at a position adjacent to the conductive location.
15. The method according to claim 14 wherein a length of a portion of the communication conductor between the conductive location and the quick connection coupler is arranged to minimize heating of the portion.
16. The method according to claim 1 wherein the electrode is a sensing electrode for use in sensing electrical signals within the body of the patient.
17. The method according to claim 1 wherein the electrode is arranged for use in applying electrical currents to the body of the patient.
18. A surface electrode to be attached to the skin of the patient for obtaining electrical signals for communicating electrical currents through the skin of the patient, the electrode being arranged to remain in place during an MR imaging method having a magnetic field, the electrode comprising:
a communication conductor for carrying the current;
a layer having a bottom surface arranged to be attached to the skin, the layer having a conductive location thereon connected to the communication conductor;
the layer being divided into separate side by side sections by slits in the layer arranged to reduce eddy currents which are induced in the surface electrodes when they are exposed to variations in the magnetic field;
the side by side sections being divided so that all are connected through the layer to the conductive location to allow the current to be connected to the communication conductor.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An induction heat treatment method for heating and quench-hardening a treatment object through induction heating, comprising:
a data acquiring step of heating and quench-hardening a sample of said treatment object to thereby acquire process data;
a storing step of storing, as said process data, power supply output transition data on transition of a power supply output outputted from a power supply for induction heating to an induction coil in order to heat the sample of said treatment object in said data acquiring step, temperature transition data on transition of temperature of the sample of said treatment object, and quenching timing data for specifying a quenching timing of the sample of said treatment object;
a checking step of checking said power supply output transition data and said quenching timing data as to validity based on said temperature transition data stored in said storing step; and
a mass production step of performing heat treatment of said treatment object in accordance with said power supply output transition data and said quenching timing data stored in said storing step and checked as to validity in said checking step, wherein
said data acquiring step includes
a temperature controlling step of adjusting the temperature of the sample of said treatment object, and
a quenching controlling step of adjusting said quenching timing, wherein
said temperature controlling step has
a heating step of heating the sample of said treatment object through induction heating,
a temperature-measuring-for-controlling-temperature step of acquiring temperature data on a heated portion of the sample of said treatment object included in said temperature transition data, and
a temperature adjusting step of outputting a temperature controlling signal to said power supply based on the temperature data acquired in said temperature-measuring-for-controlling-temperature step to control the power supply output to thereby adjust temperature for heating the sample of said treatment object, and wherein
said quenching controlling step has
a temperature-measuring-for-quenching step of acquiring temperature data on a portion away from the heated portion of the sample of said treatment object included in said temperature transition data, and
a quenching timing adjusting step of adjusting a heating time based on the temperature data acquired in said temperature-measuring-for-quenching step and outputting a quench-starting signal.
2. The induction heat treatment method according to claim 1, wherein
in said quenching timing adjusting step of said quenching controlling step, a diffusion length Dep of carbon for determining said quenching timing is obtained by following equations:
Dep=A\xd72(Dt)12
where D: diffusion constant of carbon in steel, t: holding time (second), A: correction coefficient;
D=D0 exp(\u2212QRT)
where D0: entropy term of diffusion constant, Q: activation energy, R: gas constant, T: absolute temperature (K); and
erf(A)=1\u22120.1573C1C2
where C1: solid solubility of C at 727\xb0 C., C2: solid solubility of C at arbitrary temperature.
3. The induction heat treatment method according to claim 1, wherein
in said quenching timing adjusting step of said quenching controlling step, a solution state of carbon for determining said quenching timing is obtained by following equations:
\u2202C(\u2202t)=D\u22022C(\u2202x2)
where D: diffusion constant of carbon in steel, C: carbon concentration (mass %), t: time (second), x: distance;
D=D0 exp(\u2212QRT)
where D0: entropy term of diffusion constant, Q: activation energy, R: gas constant, T: absolute temperature (K).