US4899111A
Expired / Lapsed
US
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Probe for high resolution NMR with sample reorientation
Assignee: CALIFORNIA A CORP OF, University of, Regents of
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Filing: 1988-08-03
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Granted: 1990-02-06
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Expires: 2008-08-03
Abstract
Abstract An improved NMR probe and method are described which substantially improve the resolution of NMR measurements made on powdered or amorphous or otherwise orientationally disordered samples. The apparatus mechanically varies the orientation of the sample such that the time average of two or more sets of spherical harmonic functions are zero.
Inventors
- 👤 Alexander Pines
- 👤 Ago Samoson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:33
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/30; G01R33/307
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
111 words
An apparatus for measuring the NMR spectra of a sample, said apparatus comprising: means for holding said sample in a magnetic field, the orientation of said sample being specified by a set of angles, Ω, said set of angles being measured with reference to the direction of said magnetic field; and orientation means for causing the orientation of said sample to change relative to said magnetic field, the orientation of said sample at time t being equal to Ω(t), wherein the time average of each of two different sets of spherical harmonic functions, Y lm , is substantially zero over the values Ω(t) realized during the time of said NMR measurement.
Claim 2
Independent Claim
111 words
An apparatus for measuring the NMR spectra of a sample, said apparatus comprising: means for holding said sample in a magnetic field, the orientation of said sample being specified by a set of angles, Ω, said set of angles being measured with reference to the direction of said magnetic field; and orientation means for causing the orientation of said sample to change relative to said magnetic field, the orientation of said sample at time t being equal to Ω(t), wherein the time average of each of two different sets of spherical harmonic functions, Y lm , is substantially zero over the values Ω(t) realized during the time of said NMR measurement.
Claim 3
Dependent Claim
57 words
The apparatus of claim 1 wherein said orientation means comprises: means for causing said sample holding means to spin about a sample axis; means for causing said sample axis to sweep out a cone having a predetermined opening angle, the axis of said cone being inclined at a predetermined angle to the direction of said magnetic field.
Claim 4
Dependent Claim
123 words
The apparatus of claim 2 wherein said sample holding means comprises a cylinder having an axial moment of inertia, I ax , and a transverse moment of inertia, I tr , said means for causing said sample holding means to spin comprises means for causing said cylinder to spin at an angular velocity of w 1 revolutions per second, and said means for causing said sample axis to sweep out a cone causes said axis to make one revolution on said cone every 1/w nut seconds wherein w 1 is substantially equal to (I tr -I ax )w nut cos(i 2 )/I ax , i 2 being the angle of inclination of the axis of said cone relative to said magnetic field direction.
Claim 5
Dependent Claim
36 words
The apparatus of claim 2 wherein the cosine of said opening angle is a zero of a first Legendre polynomial and the cosine of said angle of inclination is a zero of a second Legendre polynomial.
Claim 6
Dependent Claim
21 words
The apparatus of claim 4 wherein said first Legendre polynomial has order 2 and said second Legendre polynomial has order 4.
Claim 7
Dependent Claim
89 words
The apparatus of claim 2 wherein said sample holding means comprises a cylinder having a rounded end, said cylinder including impellers on the surface thereof, and wherein said means for causing said sample holding means to spin about a sample axis comprises: a frusto-conical stator having an axis inclined at said predetermined angle with respect to said magnetic field direction, and an opening angle equal to said predetermined opening angle, said stator further including means for engaging said rounded end; and means for directing air jets against said impellers.
Claim 8
Dependent Claim
21 words
The apparatus of claim 6 wherein said means for directing air jets comprises a plurality of inlet ports in said stator.
Claim 9
Dependent Claim
139 words
The apparatus of claim 2 wherein said sample holding means comprises a first cylinder having a compartment therein for holding said sample, the axis of said first cylinder being coincident with said sample axis, wherein said means for causing said sample holding means to spin comprises means for causing said first cylinder to spin about the axis thereof, and wherein said means for causing said sample axis to sweep out a cone comprises a second cylinder including means for holding said first cylinder such that the axis of said first cylinder is inclined at said opening angle with reference to the axis of said second cylinder, the axis of said second cylinder being inclined at said angle of inclination with reference to said magnetic field direction; and means for causing said second cylinder to spin about the axis thereof.
Claim 10
Independent Claim
107 words
A method for measuring the NMR spectra of a sample, said method comprising the steps of: placing said sample in a magnetic field, the orientation of said being specified by a set of angles Ω, said set of angles being measured with reference to the direction of said sample magnetic field; and causing said sample to move relative to said magnetic field such that the orientation of said sample at time t is equal to Ω(t), wherein the time average of each of two sets of spherical harmonic functions, Y lm , is substantially zero over the values Ω(t) realized during the time of said NMR measurement.
Claim 11
Independent Claim
107 words
A method for measuring the NMR spectra of a sample, said method comprising the steps of: placing said sample in a magnetic field, the orientation of said being specified by a set of angles Ω, said set of angles being measured with reference to the direction of said sample magnetic field; and causing said sample to move relative to said magnetic field such that the orientation of said sample at time t is equal to Ω(t), wherein the time average of each of two sets of spherical harmonic functions, Y lm , is substantially zero over the values Ω(t) realized during the time of said NMR measurement.
Claim 12
Dependent Claim
48 words
The method of claim 9 wherein said step of causing said sample to move comprises: spinning said sample about a sample axis; and causing said sample axis to pivot about a fixed end thereof between first and second angles with respect to the direction of said magnetic field.
Claim 13
Dependent Claim
34 words
The method of claim 10 wherein said step of causing said sample axis to pivot further comprises causing said sample axis to move at a constant angular velocity between said first and second angles.
Claim 14
Dependent Claim
55 words
The method of claim 10 wherein said step of causing said sample axis to pivot further comprises: causing said sample axis to dwell for a first time at said first angle; causing said sample axis to move to said second angle; and causing said sample to dwell for a second time at said second angle.
Claim 15
Dependent Claim
38 words
The method of claim 10 wherein said step of causing said sample axis to pivot further comprises causing said sample axis to move between said first and second angles at an angular velocity which varies sinusoidally with time.
Claim 16
Dependent Claim
58 words
The method of claim 9 wherein causing said sample to move relative to said magnetic field comprises: causing said sample to spin about a sample axis; causing said sample axis to sweep out a cone having a predetermined opening angle, the axis of said cone being inclined at a predetermined angle to the direction of said magnetic field.
Claim 17
Dependent Claim
36 words
The method of claim 14 wherein the cosine of said opening angle is a zero of a first Legendre polynomial and the cosine of said angle of inclination is a zero of a second Legendre polynomial.
Claim 18
Dependent Claim
21 words
The method of claim 15 wherein said first Legendre polynomial has order 2 and said second Legendre polynomial has order 4.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 1993-02-05 | 1993-08-07 | 1994-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-05 | 1997-08-07 | 1998-02-06 | $3760.00 | Window Closed / Lapsed |
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