US5224775A
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Method and apparatus for modulated differential analysis
Assignee: TA Instruments Inc
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Filing: 1992-03-02
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Granted: 1993-07-06
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Expires: 2012-03-02
Abstract
Abstract The present invention relates to differential analytical techniques for determining the composition, phase, structure, identification or other properties of a material that undergoes a transition as function of a driving variable. As applied to differential scanning calorimetric analysis (DSC), the preferred embodiment comprises: (1) heating a sample of the material with a linear temperature ramp that is modulated with a sinusoidal heating rate oscillation; and (2) deconvoluting the resultant heat flow signal into rapidly reversible and non-rapidly reversible components.
Inventors
- 👤 Michael Reading
- 👤 Brian K. Hahn
- 👤 Benjamin S. Crowe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:25
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/18; G01N25/20; G01N25/48; G01N25/4806; G01N25/4826; G01N25/4833; G01N25/4846; G01N25/4866
Claims Analysis
Total Claims: 60
Claim 1
Independent Claim
126 words
A method for analyzing a material that undergoes a transition as a function of temperature comprising the steps of: (a) selecting an underlying rate of change of the temperature; (b) selecting a modulation function; (c) selecting a modulation frequency; (d) selecting a modulation amplitude; (e) placing a sample of the material in an apparatus for detecting differential changes in a characterizing physical parameter of the sample with respect to a reference as a function of the temperature of the sample; (f) varying the temperature of the sample according to the selected underlying rate of change of the temperature, the selected modulation function, the selected modulation frequency and the selected modulation amplitude; and (g) recording a differential signal representative of differential changes in the characterizing physical parameter.
Claim 2
Independent Claim
126 words
A method for analyzing a material that undergoes a transition as a function of temperature comprising the steps of: (a) selecting an underlying rate of change of the temperature; (b) selecting a modulation function; (c) selecting a modulation frequency; (d) selecting a modulation amplitude; (e) placing a sample of the material in an apparatus for detecting differential changes in a characterizing physical parameter of the sample with respect to a reference as a function of the temperature of the sample; (f) varying the temperature of the sample according to the selected underlying rate of change of the temperature, the selected modulation function, the selected modulation frequency and the selected modulation amplitude; and (g) recording a differential signal representative of differential changes in the characterizing physical parameter.
Claim 3
Dependent Claim
27 words
The method of claim 1, further comprising the step of deconvoluting the signal representative of the characterizing differential physical parameter to compute at least one deconvoluted signal.
Claim 4
Dependent Claim
30 words
The method of claim 2, further comprising the step of adjusting the frequency of the modulation of the temperature of the sample according to the at least one deconvoluted signal.
Claim 5
Dependent Claim
30 words
The method of claim 2, further comprising the step of adjusting the amplitude of the modulation of the temperature of the sample according to the at least one deconvoluted signal.
Claim 6
Dependent Claim
31 words
The analytical method of claim 2, further comprising the step of controlling the underlying rate of change of the temperature of the sample according to the at least one deconvoluted signal.
Claim 7
Dependent Claim
13 words
The method of claim 1, wherein the modulation function is a sinusoidal oscillation.
Claim 8
Dependent Claim
30 words
The method of claim 1, wherein the modulation function is selected from the group of modulation functions consisting of square waves, sawtooth waves, triangular waves, pulse waves, and combinations thereof.
Claim 9
Dependent Claim
13 words
The method of claim 1, wherein the modulation function is a polynomial wave.
Claim 10
Dependent Claim
23 words
The method of claim 1, further comprising deconvoluting the signal representative of the characterizing physical parameters into rapidly reversible and non-rapidly reversible components.
Claim 11
Dependent Claim
23 words
The method of claim 9, wherein the modulation frequency is selected to improve the separation between the rapidly reversible and non-rapidly reversible signals.
Claim 12
Dependent Claim
23 words
The method of claim 9, wherein the modulation amplitude is selected to improve the separation between the rapidly reversible and non-rapidly reversible signals.
Claim 13
Dependent Claim
13 words
The method of claim 1, wherein the characterizing physical parameter is heat flow.
Claim 14
Dependent Claim
13 words
The method of claim 1 wherein the characterizing physical parameter is sample weight.
Claim 15
Dependent Claim
21 words
The method of claim 1, further comprising deconvoluting the signal representative of the characterizing physical parameter using a discrete Fourier transform.
Claim 16
Dependent Claim
33 words
The method of claim 1, further comprising deconvoluting the signal representative of the characterizing physical parameter using a polynomial expression containing the rate of change of the temperature in at least one term.
Claim 17
Dependent Claim
28 words
The method of claim 1, further comprising deconvoluting the signal representative of the physical parameter by determining the envelope of the signal representative of the characterizing physical parameter.
Claim 18
Dependent Claim
127 words
An analytical apparatus comprising: (a) means for varying the temperature of a sample at an underlying rate of change; (b) means for selecting a modulation function, a modulation frequency and a modulation amplitude; (c) means for modulating the temperature of the sample according to the selected modulation function, modulation frequency and modulation amplitude; (d) means for detecting a signal representative of differential changes in a characterizing physical parameter of a sample with respect to a reference as a function of the temperature, as the temperature is varied according to the underlying rate of change of the temperature, and modulated according to the modulation function, the modulation frequency and the modulation amplitude; and (e) means for recording the signal representative of differential changes in the characterizing physical parameter.
Claim 19
Dependent Claim
127 words
An analytical apparatus comprising: (a) means for varying the temperature of a sample at an underlying rate of change; (b) means for selecting a modulation function, a modulation frequency and a modulation amplitude; (c) means for modulating the temperature of the sample according to the selected modulation function, modulation frequency and modulation amplitude; (d) means for detecting a signal representative of differential changes in a characterizing physical parameter of a sample with respect to a reference as a function of the temperature, as the temperature is varied according to the underlying rate of change of the temperature, and modulated according to the modulation function, the modulation frequency and the modulation amplitude; and (e) means for recording the signal representative of differential changes in the characterizing physical parameter.
Claim 20
Dependent Claim
14 words
The analytical apparatus of claim 17, wherein the characterizing physical parameter is heat flow.
Claim 21
Dependent Claim
14 words
The analytical apparatus of claim 17, wherein the characterizing physical parameter is sample weight.
Claim 22
Dependent Claim
14 words
The analytical apparatus of claim 17, wherein the apparatus is a Differential Scanning Calorimeter.
Claim 23
Dependent Claim
50 words
The analytical apparatus of claim 17, wherein the apparatus is selected from the group of differential analysis apparatus consisting of a Pressure Differential Calorimeter, a Differential Thermal Analysis apparatus, a Pressure Differential Thermal Analysis apparatus, a Differential Photocalorimeter, a Pressure Differential Photocalorimeter, a Differential Thermogravimeter, and a Pressure Differential Thermogravimeter.
Claim 24
Dependent Claim
12 words
The analytical apparatus of claim 17, wherein the modulation function is sinusoidal.
Claim 25
Dependent Claim
31 words
The analytical apparatus of claim 17, wherein the modulation function is selected from the group of modulation functions consisting of square waves, sawtooth waves, triangular waves, pulse waves, and combinations thereof.
Claim 26
Dependent Claim
29 words
The analytical apparatus of claim 17, further comprising means for deconvoluting the signal representative of differential changes in the characterizing physical parameter into rapidly reversible and non-rapidly reversible components.
Claim 27
Dependent Claim
30 words
The analytical apparatus of claim 24, wherein said means for deconvoluting the signal representative of differential changes in the characterizing physical parameter comprises means for carrying out discrete Fourier transforms.
Claim 28
Dependent Claim
51 words
The analytical apparatus of claim 24, wherein said means for deconvoluting the signal representative of differential changes in the physical parameter comprises means for fitting the signal to a polynomial expression containing the rate of change of the driving variable in at least one of the terms of the polynomial expression.
Claim 29
Independent Claim
140 words
A method for analyzing a material that undergoes a transition as a function of a driving variable comprising the steps of: (a) placing a sample of the material in an apparatus for detecting differential changes in a characterizing physical parameter of the sample with respect to a reference as a function of the driving variable; (b) varying the driving variable at an underlying rate of change modulated by a modulation function, said modulation function having a preselected modulation frequency and a preselected modulation amplitude; (c) monitoring a differential signal representative of differential changes in the characterizing physical parameter; (d) controlling the underlying rate of change of the driving variable according to changes in the differential signal representative of differential change in the characterizing physical parameter; and (e) recording the differential signal representative of differential changes in the characterizing physical parameter.
Claim 30
Independent Claim
140 words
A method for analyzing a material that undergoes a transition as a function of a driving variable comprising the steps of: (a) placing a sample of the material in an apparatus for detecting differential changes in a characterizing physical parameter of the sample with respect to a reference as a function of the driving variable; (b) varying the driving variable at an underlying rate of change modulated by a modulation function, said modulation function having a preselected modulation frequency and a preselected modulation amplitude; (c) monitoring a differential signal representative of differential changes in the characterizing physical parameter; (d) controlling the underlying rate of change of the driving variable according to changes in the differential signal representative of differential change in the characterizing physical parameter; and (e) recording the differential signal representative of differential changes in the characterizing physical parameter.
Claim 31
Dependent Claim
27 words
The method of claim 27, further comprising the step of deconvoluting the signal representative of the characterizing differential physical parameter to compute at least one deconvoluted signal.
Claim 32
Dependent Claim
13 words
The method of claim 27, wherein the modulation function is a sinusoidal oscillation.
Claim 33
Dependent Claim
30 words
The method of claim 27, wherein the modulation function is selected from the group of modulation functions consisting of square waves, sawtooth waves, triangular waves, pulse waves, and combinations thereof.
Claim 34
Dependent Claim
27 words
The method of claim 27, further comprising deconvoluting the signal representative of the characterizing physical parameter and the driving variable into rapidly reversible and non-rapidly reversible components.
Claim 35
Dependent Claim
11 words
The method of claim 27, wherein the driving variable is temperature.
Claim 36
Dependent Claim
13 words
The method of claim 32, wherein the characterizing physical parameter is heat flow.
Claim 37
Dependent Claim
13 words
The method of claim 32, wherein the characterizing physical parameter is sample weight.
Claim 38
Dependent Claim
21 words
The method of claim 27, further comprising deconvoluting the signal representative of the characterizing physical parameter using a discrete Fourier transform.
Claim 39
Independent Claim
117 words
A method for analyzing a material that undergoes a transition as a function of pressure comprising the steps of: (a) selecting an underlying rate of change of pressure; (b) selecting a modulation function; (c) selecting a modulation frequency; (d) selecting a modulation amplitude; (e) placing a sample of the material in an apparatus for detecting differential changes in a characterizing physical parameter of the sample with respect to a reference as a function of pressure; (f) varying the pressure according to the selected underlying rate of change of pressure, the selected modulation function, the selected modulation frequency and the selected modulation amplitude; and (g) recording a differential signal representative of differential changes in the characterizing physical parameter.
Claim 40
Independent Claim
117 words
A method for analyzing a material that undergoes a transition as a function of pressure comprising the steps of: (a) selecting an underlying rate of change of pressure; (b) selecting a modulation function; (c) selecting a modulation frequency; (d) selecting a modulation amplitude; (e) placing a sample of the material in an apparatus for detecting differential changes in a characterizing physical parameter of the sample with respect to a reference as a function of pressure; (f) varying the pressure according to the selected underlying rate of change of pressure, the selected modulation function, the selected modulation frequency and the selected modulation amplitude; and (g) recording a differential signal representative of differential changes in the characterizing physical parameter.
Claim 41
Dependent Claim
27 words
The method of claim 36, further comprising the step of deconvoluting the signal representative of the characterizing differential physical parameter to compute at least one deconvoluted signal.
Claim 42
Dependent Claim
27 words
The method of claim 37, further comprising the step of adjusting the frequency of the modulation of the pressure according to the at least one deconvoluted signal.
Claim 43
Dependent Claim
27 words
The method of claim 37, further comprising the step of adjusting the amplitude of the modulation of the pressure according to the at least one deconvoluted signal.
Claim 44
Dependent Claim
28 words
The analytical method of claim 37, further comprising the step of controlling the underlying rate of change of the pressure according to the at least one deconvoluted signal.
Claim 45
Dependent Claim
13 words
The method of claim 36, wherein the modulation function is a sinusoidal oscillation.
Claim 46
Dependent Claim
30 words
The method of claim 36, wherein the modulation function is selected from the group of modulation functions consisting of square waves, sawtooth waves, triangular waves, pulse waves, and combinations thereof.
Claim 47
Dependent Claim
13 words
The method of claim 36, wherein the modulation function is a polynomial wave.
Claim 48
Dependent Claim
26 words
The method of claim 36, further comprising deconvoluting the signal representative of the characterizing physical parameter and the pressure into rapidly reversible and non-rapidly reversible components.
Claim 49
Dependent Claim
23 words
The method of claim 44, wherein the modulation frequency is selected to improve the separation between the rapidly reversible and non-rapidly reversible signals.
Claim 50
Dependent Claim
23 words
The method of claim 44, wherein the modulation amplitude is selected to improve the separation between the rapidly reversible and non-rapidly reversible signals.
Claim 51
Dependent Claim
21 words
The method of claim 36, further comprising deconvoluting the signal representative of the characterizing physical parameter using a discrete Fourier transform.
Claim 52
Dependent Claim
33 words
The method of claim 36, further comprising deconvoluting the signal representative of the characterizing physical parameter using a polynomial expression containing the rate of change of the pressure in at least one term.
Claim 53
Dependent Claim
28 words
The method of claim 36, further comprising deconvoluting the signal representative of the physical parameter by determining the envelope of the signal representative of the characterizing physical parameter.
Claim 54
Dependent Claim
124 words
An analytical apparatus comprising: (a) means for varying the pressure on a sample at an underlying rate of change; (b) means for selecting a modulation function, a modulation frequency and a modulation amplitude; (c) means for modulating the pressure according to the selected modulation function, modulation frequency and modulation amplitude; (d) means for detecting a signal representative of differential changes in a characterizing physical parameter of a sample with respect to a reference as a function of the pressure, as the pressure is varied according to the underlying rate of change of the pressure, and modulated according to the modulation function, the modulation frequency and the modulation amplitude; and (e) means for recording the signal representative of differential changes in the characterizing physical parameter.
Claim 55
Dependent Claim
124 words
An analytical apparatus comprising: (a) means for varying the pressure on a sample at an underlying rate of change; (b) means for selecting a modulation function, a modulation frequency and a modulation amplitude; (c) means for modulating the pressure according to the selected modulation function, modulation frequency and modulation amplitude; (d) means for detecting a signal representative of differential changes in a characterizing physical parameter of a sample with respect to a reference as a function of the pressure, as the pressure is varied according to the underlying rate of change of the pressure, and modulated according to the modulation function, the modulation frequency and the modulation amplitude; and (e) means for recording the signal representative of differential changes in the characterizing physical parameter.
Claim 56
Dependent Claim
12 words
The analytical apparatus of claim 50, wherein the modulation function is sinusoidal.
Claim 57
Dependent Claim
31 words
The analytical apparatus of claim 50, wherein the modulation function is selected from the group of modulation functions consisting of square waves, sawtooth waves, triangular waves, pulse waves, and combinations thereof.
Claim 58
Dependent Claim
29 words
The analytical apparatus of claim 50, further comprising means for deconvoluting the signal representative of differential changes in the characterizing physical parameter into rapidly reversible and non-rapidly reversible components.
Claim 59
Dependent Claim
29 words
The analytical apparatus of claim 50, wherein said means for deconvoluting the signal representative of differential changes in the characterizing physical parameter comprises means for carrying out Fourier transforms.
Claim 60
Dependent Claim
50 words
The analytical apparatus of claim 50, wherein said means for deconvoluting the signal representative of differential changes in the physical parameter comprises means for fitting the signal to a polynomial expression containing the rate of change of the pressure in at least one of the terms of the polynomial expression.
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