What is claimed is:
1. An apparatus for measuring a characteristic of a specimen, comprising:
a probe for scanning a surface of the specimen in a noncontacting state;
vibrating means for vibrating the probe;
excitation field generating means for generating an amplitude modulation signal which is amplitude-modulated with a modulation frequency and a carrier frequency and producing an excitation field at the surface of the specimen on the basis of the generated amplitude modulation signal; and
measuring means for measuring a change in a vibration frequency of the probe according to the excitation field generated at the surface of the specimen.
2. The apparatus according to claim 1, wherein the measuring means measures a shift of the probe according to the excitation field generated on the surface of the specimen, and measures the change in the vibration frequency on the basis of the shift of the probe.
3. The apparatus according to claim 1, wherein the vibrating means includes a cantilever having a resonance frequency, and vibration signal generating means for generating a signal to vibrate the cantilever at a cantilever resonance frequency or a frequency near the cantilever resonance frequency, and
the measuring means senses a phase shift of a vibration frequency of the probe with respect to the vibration frequency of the signal generated at the vibration signal generating means.
4. The apparatus according to claim 1, wherein the vibrating means includes a cantilever having a resonance frequency and causes the cantilever to vibrate the probe at a cantilever resonance frequency or a frequency near the cantilever resonance frequency, and
the excitation field generating means uses a carrier frequency higher than the resonance frequency.
5. The apparatus according to claim 1, wherein the vibrating means includes a cantilever having a resonance frequency and causes the cantilever to vibrate the probe, and
the excitation field generating means uses a modulation frequency lower than {fraction (110)} of the resonance frequency.
6. The apparatus according to claim 2, wherein, of a signal representing the measured frequency shift or phase shift of the vibration of the probe, the measuring means measures a component synchronizing with a harmonic once or twice as high as the modulation frequency used in generating the amplitude modulation signal.
7. The apparatus according to claim 1, wherein the vibrating means includes a cantilever which vibrates the probe and has a spring constant at which the probe does not jump in the specimen.
8. The apparatus according to claim 1, wherein the vibrating means includes a cantilever which vibrates the probe and has a spring constant according to an excitation field at the specimen.
9. The apparatus according to claim 1, wherein the vibrating means includes a cantilever which supports the probe at one end and vibrates the probe and a vibrating piezoelectric element which supports the other end of the cantilever and vibrates the cantilever.
10. An apparatus for measuring a characteristic of a specimen, comprising:
a probe for scanning a surface of the specimen in a noncontacting state;
vibrating means for vibrating the probe;
excitation field generating means for generating an amplitude modulation signal which is amplitude-modulated with a modulation frequency and a carrier frequency and producing an excitation field at the surface of the specimen on the basis of the generated amplitude modulation signal; and
measuring means for measuring a force gradient induced to the probe by the excitation field generated at the surface of the specimen.
11. The apparatus according to claim 10, wherein the measuring means measures a phase shift of a vibration of the probe caused by the excitation field generated on the surface of the specimen, measures a modulation frequency component included in the phase shift, and measures the force gradient on the basis of the modulation frequency component.
12. The apparatus according to claim 10, wherein the vibrating means includes a cantilever having a resonance frequency, and vibration signal generating means for generating a signal to vibrate the cantilever at a cantilever resonance frequency or a frequency near the cantilever resonance frequency, and
the measuring means senses a phase shift of a vibration frequency of the probe with respect to the vibration frequency of the signal generated at the vibration signal generating means.
13. The apparatus according to claim 10, wherein the vibrating means includes a cantilever having a resonance frequency and causes the cantilever to vibrate the probe at a cantilever resonance frequency or a frequency near the cantilever resonance frequency, and
the excitation field generating means uses a carrier frequency higher than the resonance frequency.
14. The apparatus according to claim 10, wherein the vibrating means includes a cantilever having a resonance frequency and causes the cantilever to vibrate the probe, and
the excitation field generating means uses a modulation frequency lower than {fraction (110)} of the resonance frequency.
15. The apparatus according to claim 11, wherein, of a signal representing the measured phase shift of the vibration of the probe, the measuring means measures a component synchronizing with a harmonic once or twice as high as the modulation frequency used in generating the amplitude modulation signal.
16. The apparatus according to claim 10, wherein the vibrating means includes a cantilever which vibrates the probe and has a spring constant at which the probe does not jump in the specimen.
17. The apparatus according to claim 10, wherein the vibrating means includes a cantilever which vibrates the probe and has a spring constant according to a material of the specimen.
18. The apparatus according to claim 10, wherein the vibrating means includes a cantilever which vibrates the probe and has a spring constant according to an excitation field at the specimen.
19. The apparatus according to claim 10, wherein the vibrating means includes a cantilever which supports the probe at one end and vibrates the probe and a vibrating piezoelectric element which supports the other end of the cantilever and vibrates the cantilever.
20. An apparatus for measuring a characteristic of a magnetic recording head, comprising:
a probe for scanning a surface of the magnetic recording head in a noncontacting state;
vibrating means for vibrating the probe;
current generating means for generating an amplitude modulation current and applying the generated current to the magnetic recording head; and
measuring means for measuring a force gradient induced to the probe by the magnetic field generated at the surface of the magnetic recording head according to the application of the amplitude modulation current.
21. The apparatus according to claim 20, wherein the measuring means senses a phase shift of a vibration of the probe caused by the magnetic field generated by the magnetic recording head, measures a modulation frequency component included in the phase shift, and measures the force gradient on the basis of the modulation frequency component.
22. The apparatus according to claim 20, wherein the vibrating means includes a cantilever having a resonance frequency and vibrating signal generating means for generating a signal to vibrate the cantilever at a vibration frequency which is the resonance frequency or a frequency near the resonance frequency, and
the measuring means senses a phase shift of a vibration frequency of the probe with respect to the vibration frequency of the signal generated at the vibrating signal generating means.
23. The apparatus according to claim 20, further comprising force gradient image obtaining means for obtaining a force gradient image reflecting a distribution of the magnetic field generated by the magnetic recording head, on the basis of the force gradient measured by the measuring means at a plurality of measuring points on the magnetic recording head.
24. The apparatus according to claim 20, wherein the vibrating means includes a cantilever having a resonance frequency and causes the cantilever to vibrate the probe at a vibration frequency which is the resonance frequency or a frequency near the resonance frequency, and
the current generating means generates an amplitude modulation current according to an amplitude modulation signal including a modulation frequency of and a carrier frequency, the carrier frequency being higher than the resonance frequency.
25. The apparatus according to claim 20, wherein the vibrating means includes a cantilever having a resonance frequency and causes the cantilever to vibrate the probe, and
the current generating means generates a amplitude modulation current according to an amplitude modulation signal including a modulation frequency and a carrier frequency, the modulation frequency being lower than {fraction (110)} of the resonance frequency.
26. An apparatus for measuring a characteristic of a magnetic recording head, comprising:
a probe for scanning a surface of the magnetic recording head in a noncontacting state;
vibrating means for vibrating the probe;
signal generating means for generating an amplitude modulation signal on the basis of a carrier frequency and varying a value of the amplitude modulation signal by changing a value of the carrier frequency;
a head amplifier equivalent circuit for generating an amplitude modulation current to cause the magnetic recording head to operate on the basis of the amplitude modulation signal and applying the generated current to the magnetic recording head, the head amplifier equivalent circuit having an electrical characteristic equivalent to an actual head driving amplifier;
phase shift measuring means for measuring a phase shift of a vibration of the probe according to the magnetic field generated by the magnetic recording head; and
magnetic field frequency dependence measuring means for measuring a change in a value of the phase shift with respect to a change in the value of the amplitude modulation signal caused by the signal generating means as a magnetic field frequency dependence of the magnetic recording head.
27. The apparatus according to claim 26, further comprising:
current measuring means for measuring a value of the amplitude modulation current the head amplifier equivalent circuit applies to the magnetic recording head; and
current frequency dependence measuring means for measuring a change in the value of the amplitude modulation current with respect to a change in the value of the amplitude modulation signal caused by the signal generating means as a current frequency dependence of the magnetic recording head.
28. The apparatus according to claim 26, further comprising:
amplitude control means for controlling the signal generating means to change the value of the amplitude modulation signal such that the value of the amplitude modulation current is equal to a reference value, wherein
the magnetic field frequency dependence measuring means measures a change in the value of the modulation frequency with respect to a change in the value of the amplitude modulation signal caused by the signal generating means as a magnetic field frequency dependence of the magnetic recording head.
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. A quaternary oxide foam, comprising an open-cell foam comprising titanium oxide containing:
(a) a dopant metal comprising palladium,
(b) a dopant nonmetal,
(c) titanium, and
(d) oxygen,
wherein the dopant metal is present at a concentration of at most 2 wt. %, and wherein the open-cell foam comprises a pore size distribution having at least two peaks.
2. The quaternary oxide foam of claim 1, wherein the atomic ratio of titanium, oxygen and dopant nonmetal is 1:0.5-1.99:0.01-1.5.
3. The quaternary oxide foam of claim 1, wherein the atomic ratio of titanium, oxygen and dopant nonmetal is 1:1.9-1.99:0.01-0.1.
4. The quaternary oxide foam of claim 1, wherein the dopant nonmetal is nitrogen.
5. The quaternary oxide foam of claim 4, wherein the foam has a porosity of at least 90%.
6. The quaternary oxide foam of claim 4, wherein the foam has a porosity of 90-98%.
7. The quaternary oxide foam of claim 4, wherein the foam is monolithic with a longest dimension of at least 0.1 mm.
8. The quaternary oxide foam of claim 4, wherein the foam is monolithic with a longest dimension of at least 0.5 mm.
9. The quaternary oxide foam of claim 4, wherein the foam is monolithic with a longest dimension at least 1 mm.
10. The quaternary oxide foam of claim 4, wherein visible light will lose less than 75% of its intensity when passed through 1 cm of the foam.
11. The quaternary oxide foam of claim 4, wherein visible light will lose less than 50% of its intensity when passed through 1 cm of the foam.
12. A method of catalyzing a reaction, comprising:
exposing a quaternary oxide foam to light; and
contacting the quaternary oxide foam with a reactant, to form a product of the reaction;
wherein the quaternary oxide foam comprises an open-cell foam comprising titanium oxide containing:
(a) a dopant metal comprising palladium,
(b) a dopant nonmetal,
(c) titanium, and
(d) oxygen,
wherein the dopant metal is present at a concentration of at most 2 wt. %, and wherein the open-cell foam comprises a pore size distribution having at least two peaks.
13. A reactor, comprising:
(i) an inlet,
(ii) an outlet, and
(iii) a catalyst, fluidly connected to the inlet and the outlet,
wherein the catalyst comprises a quaternary oxide foam comprising an open-cell foam comprising titanium oxide containing:
(a) a dopant metal comprising palladium,
(b) a dopant nonmetal,
(c) titanium, and
(d) oxygen,
wherein the dopant metal is present at a concentration of at most 2 wt. %, and wherein the open-cell foam comprises a pore size distribution having at least two peaks.
14. A quaternary oxide foam, prepared by a method comprising:
impregnating an open-cell template foam with a liquid mixture; and
heating the impregnated open-cell foam, to form the quaternary oxide foam comprising titanium dioxide including a dopant metal and a dopant nonmetal;
wherein the liquid mixture contains
(a) the dopant metal comprising palladium,
(b) the dopant nonmetal, and
(c) titanium,
wherein the dopant metal is present in the quaternary oxide foam at a concentration of at most 2 wt. %, and wherein the open-cell foam comprises a pore size distribution having at least two peaks.