1. Apparatus comprising:
a tuning fork having first and second tines,
a first magnet disposed on said first tine, and
a second magnet disposed on said second tine,
wherein said magnets have anti-parallel magnetic moments, said tines are elongated in a particular direction, and said anti-parallel magnetic moments are oriented essentially along said direction.
2. The apparatus of claim 1, wherein said magnets comprise permanent magnets.
3. The apparatus of claim 1, wherein said magnets comprise electromagnets.
4. Apparatus comprising at least two apparatuses accordingly to claim 1, the tuning fork of one of said apparatuses being oriented so that a line through the tips of its tines is essentially perpendicular to the corresponding line of the tuning fork of another of said apparatuses.
5. The apparatus of claim 1, further including
a drive circuit for causing said apparatus to oscillate at or near its resonant frequency; and
a detection system of sensing changes in a parameter of said oscillation induced by the presence of a magnetic field.
6. The apparatus of claim 1, further including a vacuum enclosure, said apparatus being disposed within said enclosure.
7. The apparatus of claim 1, wherein said tuning fork comprises a piezoelectric material.
8. A magnetometer comprising:
a vacuum enclosure,
apparatus having a resonant frequency, said apparatus being disposed within said enclosure and including
a piezoelectric tuning fork having first and second tines, each of said tines having a surface on a free end thereof,
a first permanent magnet disposed on said free end surface of said first tine,
a second permanent magnet disposed on said free end surface of said second tine;
said tines being elongated in a particular direction and said magnets having anti-parallel magnetic moments that are oriented essentially along said direction,
a drive circuit for causing said apparatus to oscillate at or near said resonant frequency,
a detection system of sensing magnetic-field-induced changes in the frequency, amplitude or phase of said oscillation caused by the presence of a magnetic field having at least a component oriented parallel to the imaginary line joining the ends of said tines.
9. A method comprising the steps of:
locating apparatus in a magnetic field, the apparatus including a tuning fork having first and second tines, a first magnet disposed on the first tine, and a second magnet disposed on the second tine, Wherein said magnets have anti-parallel magnetic moments, said lines are elongated in a particular direction, and said anti-parallel magnetic moments are oriented essentially along said direction,
causing the apparatus to oscillate at or near its resonant frequency, and
detecting magnetic-field-induced changes in a parameter of the oscillation.
10. The method of claim 9, wherein the detecting step includes sensing changes in the frequency, phase or amplitude of the oscillation.
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 water resistant and ventilatory examining device for cloth comprising:
a first container (10) having two opposite open ends;
a second container (12) having a closed end and an open end;
means for combining the first container (10) and the second container (12), wherein the combining means is a ring-like member and has an upper ring formed on a top periphery of the member and a lower formed on a bottom periphery of the member such that the upper ring and the bottom ring are able to respectively engage with a bottom periphery of the first container and a top periphery of the second container in a watertight manner; and,
an air supply device (14) in connection with the second container (12) to supply air into the second container,
whereby after a cloth is sandwiched between the combining means and the first container (10), the first container (10) is filled with water and the second container (12) is supplied with air such that observation made to see if water seeps through the cloth and air passes through the cloth is able to test capabilities of the cloth.
2. The examining device as claimed in claim 1, wherein the air supply device (14) includes an air bulb (141), a tube (142) extending out of the air bulb (141) and a nozzle (143) formed on a free end of the tube (142) to engage with an air hole (120) defined in a side wall of the second container (12) such that squeezing the air bulb (141) is able to pump air into the second container (12).
3. The examining device as claimed in claim 1, wherein the upper ring (15a) has a first annular projection (151) and the lower ring has a second annular projection (152) to respectively engage with the bottom periphery of the first container (10) and the top periphery of the second container (12) in a watertight manner.
4. The examining device as claimed in claim 3, wherein the air supply device (14) includes an air bulb (141), a tube (142) extending out of the air bulb (141) and a nozzle (143) formed on a free end of the tube (142) to engage with an air hole (120) defined in a side wall of the second container (12) such that squeezing the air bulb (141) is able to pump air into the second container (12).
5. The examining device as claimed in claim 3, wherein the first container (10) has a first groove (11) defined in an outer periphery of the first container (10) to receive therein the first annular projection (151) and the second container (12) has a second groove (13) define in an outer periphery of the second container (12) to receive therein the second annular projection (152).
6. The examining device as claimed in claim 5, wherein the air supply device (14) includes an air bulb (141), a tube (142) extending out of the air bulb (141) and a nozzle (143) formed on a free end of the tube (142) to engage with an air hole (120) defined in a side wall of the second container (12) such that squeezing the air bulb (141) is able to pump air into the second container (12).
7. A water resistant and ventilatory examining device for cloth comprising:
a first container having two opposite open ends;
a second container having a closed end and an open end;
means for combining the first container and the second container, and,
an air supply device in connection with the second container to supply air into the second container,
whereby after a cloth is sandwiched between the combining means and the first container, the first container is filled with water and the second container is supplied with air such that observation made to see if water seeps through the cloth and air passes through the cloth is able to test capabilities of the cloth, wherein the combining means has a top ring (21) formed on a top periphery of the first container (20) and having a plurality of through holes (210) defined through the top ring (21), a bottom ring (23) formed on a bottom periphery of the second container (22) and having a plurality of threaded holes (230) corresponding to the through holes (210) of the top ring (21), a plurality of threaded bolts (251) extending through the through holes (210) and screwingly received into the threaded holes (230) and a plurality of nuts (252) engaging with the respective threaded bolts (251) to secure engagement between the first container (20) and the second container (22).
8. The examining device as recited in claim 7, wherein the air supply comprises an air bulb, a tube connected to and extending out of the air bulb, and a nozzle formed on a free end of the tube to engage with an air hole defined in a side wall of the second container such that squeezing the air bulb causes air to be pumped into the second container.