1. A motor comprising:
first and second pole pieces on a first part of a motor, the first and second pole pieces having respective sets of teeth spaced regularly on respective faces of the first and second pole pieces;
at least one motor coil to at least in part effect motor motion between the first part of a motor and a second part of the motor when the at least one motor coil is driven, the respective sets of teeth of the first and second pole pieces magnetically interacting with corresponding sets of regularly spaced teeth on the second part of the motor when the at least one motor coil is driven;
first and second sensing coils coupled to the first and second pole pieces and arranged to detect changes in magnetic flux coupling between the teeth of the first pole piece and the second part of the motor, on the one hand, and between the teeth of the second pole piece and the second part of the motor, on the other hand; and
third and fourth sensing coils coupled to the first and second pole pieces and arranged to detect changes in magnetic flux coupling between the teeth of the first pole piece and the second part of the motor, on the one hand, and between the teeth of the second pole piece and the second part of the motor, on the other hand;
wherein the teeth on the first and second parts of the motor are arranged to produce a different variation period in the magnetic flux coupled through the third and fourth sensing coils than the magnetic flux coupled through the first and second sensing coils as a function of the relative positioning of the first part of the motor to the second part of the motor.
2. The motor of claim 1, wherein the first part of the motor is a stator and the second part of the motor is a cylindrical rotor having first and second cap pieces and an additional rotor segment, the corresponding sets of regularly spaced teeth comprising first and second sets of teeth on the first and second cap pieces, with the rotor segment comprising a set of regularly spaced teeth,
wherein the number of teeth on the first and second pole pieces is different from the number of teeth on the rotor segment.
3. The motor of claim 1, wherein the first part of the motor is a forcer and the second part of the motor is a platen having at least a planar portion, the corresponding sets of regularly spaced teeth spaced apart on the planar portion of the platen, wherein the first and second sensing coils sense flux through teeth spaced at a first distance, and the third and fourth sensing coils sense flux through another set of teeth spaced differently from the first distance.
4. The motor of claim 1, wherein the first part of the motor is a forcer and the second part of the motor is an essentially cylindrical bar, the corresponding sets of regularly spaced teeth inscribed about a portion of the circumference of the cylinder spaced apart along the linearly axis of the cylinder, with a second set of teeth inscribed about a different portion of the circumference having a different spacing along the linear axis of the cylinder, wherein the first and second sensing coils sense flux through teeth spaced at a first distance, and the third and fourth sensing coils sense flux the second set of teeth spaced differently from the first distance.
5. The motor of claim 2, wherein the set of teeth spaced at a first distance and the set of teeth spaced at the distance different from the first distance are arranged in non-parallel patterns.
6. The motor and sensor of claim 1, wherein the sensing coils are coupled to electronics to provide a signal corresponding to an absolute position measure of the rotor assembly.
7. The motor and sensor of claim 1, further comprising sensing electronics for processing signals from the sensing coils and electronics controlling current through the stator poles integrated with the sensing electronics.
8. The motor and sensor of claim 1, wherein waveforms driving the coils for electrically energizing are coordinated to prevent essentially simultaneous transitions of these waveforms.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A polysaccharide sponge comprising a crosslinked polysaccharide obtained by crosslinking a photoreactive polysaccharide, and having not less than 760 pores per an unit area (1 cm2) among which not less than 50% of said pores have a pore diameter of 10 to 50 m.
2. A polysaccharide sponge according to claim 1, wherein when being immersed in a largely excessive amount of distilled water at 24 C., said polysaccharide sponge still maintains a spongy structure even after the elapse of one hour.
3. A polysaccharide sponge producible by a process comprising the steps of:
(A) freezing a photoreactive polysaccharide solution; and
(B) irradiating the frozen photoreactive polysaccharide solution with light to crosslink the photoreactive polysaccharide, thereby obtaining the polysaccharide sponge.
4. A polysaccharide sponge producible by a process comprising the steps of:
(C) freeze-drying a photoreactive polysaccharide solution; and
(D) irradiating the freeze-dried product with light to crosslink the photoreactive polysaccharide, thereby obtaining the polysaccharide sponge.
5. A polysaccharide sponge according to any one of claims 1 to 4, wherein said polysaccharide is at least one compound selected from the group consisting of hyaluronic acid, chondroitin sulfate, heparin, heparan sulfate, keratan sulfate, chitin, chitosan, alginic acid and carboxymethyl cellulose.
6. A polysaccharide sponge according to any one of claims 1 to 5, wherein said photoreactive polysaccharide is a polysaccharide to which a photo-crosslinking group having cinnamic acid, substituted cinnamic acid, furyl acrylic acid or thiophene acrylic acid as a photoreactive residue, is bonded.
7. A process for producing a polysaccharide sponge, comprising the steps of:
(A) freezing a photoreactive polysaccharide solution; and
(B) irradiating the frozen photoreactive polysaccharide solution with light to crosslink the photoreactive polysaccharide, thereby obtaining the polysaccharide sponge.
8. A process for producing a polysaccharide sponge, comprising the steps of:
(C) freeze-drying a photoreactive polysaccharide solution; and
(D) irradiating the freeze-dried product with light to crosslink the photoreactive polysaccharide, thereby obtaining the polysaccharide sponge.
9. A process according to claim 7 or 8, wherein said polysaccharide is at least one compound selected from the group consisting of hyaluronic acid, chondroitin sulfate, heparin, heparan sulfate, keratan sulfate, chitin, chitosan, alginic acid and carboxymethyl cellulose.
10. A process according to any one of claims 7 to 9, wherein said photoreactive polysaccharide is a polysaccharide to which a photo-crosslinking group having cinnamic acid, substituted cinnamic acid, furyl acrylic acid or thiophene acrylic acid as a photoreactive residue, is bonded.
11. A photoreactive polysaccharide sponge comprising a photoreactive polysaccharide, and having not less than 760 pores per an unit area (1 cm2) among which not less than 50% of said pores have a pore diameter of 10 to 50 m.
12. A photoreactive polysaccharide sponge produced by freeze-drying a photoreactive polysaccharide solution.
13. A photoreactive polysaccharide sponge according to claim 11 or 12, wherein said polysaccharide is at least one compound selected from the group consisting of hyaluronic acid, chondroitin sulfate, heparin, heparan sulfate, keratan sulfate, chitin, chitosan, alginic acid and carboxymethyl cellulose.
14. A photoreactive polysaccharide sponge according to any one of claims 11 to 13, wherein said photoreactive polysaccharide is a polysaccharide to which a photo-crosslinking group having cinnamic acid, substituted cinnamic acid, furyl acrylic acid or thiophene acrylic acid as a photoreactive residue, is bonded.
15. A photoreactive polysaccharide comprising alginic acid to which a photo-crosslinking group having cinnamic acid or substituted cinnamic acid as a photoreactive residue, is bonded.
16. A photoreactive polysaccharide comprising carboxymethyl cellulose to which a photo-crosslinking group having cinnamic acid or substituted cinnamic acid as a photoreactive residue, is bonded.
17. A photoreactive polysaccharide comprising hyaluronic acid to which a photo-crosslinking group having furyl acrylic acid or thiophene acrylic acid as a photoreactive residue, is bonded.
18. A crosslinked polysaccharide produced by irradiating said photoreactive polysaccharide as claimed in any of claims 15 to 17 with light.