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Push-Button Analysis Aids continued...

Relaxation time measurements
The spin-lattice relaxation time can be connected with a time scale for a spin's return to equilibrium with its surroundings after being externally excited from such a state. This time scale points to the magnetic couplings between the probe nucleus and its surroundings - which for our system has information about how quickly it is traversing those surroundings, as well as energy scales for the barriers in its way. The measurement consists of "exciting" the lithium spin system from its equilibrium state and then "querying" its state at various times along its return to equilibrium.

We discovered Origin™ v 5.0, which is a Windows-based technical graphics and data analysis software package from OriginLab Corporation, located in Northampton, Massachusetts. This software package provides several crucial advantages that make it ideally suited for this application. Origin provides a wide range of analytical capabilities including a Fast Fourier Transform function that allows us to view our results in frequency as well as time domain. It provides a wide range of graphing capabilities, allowing the user to adjust virtually any parameter of the graph simply by clicking on it with a mouse. Finally, Origin utilizes an extremely powerful programming language called LabTalk™ that provides access to virtually all functionality of the program.

Scripts automate analysis
Working with Origin application programmers, we developed a series of LabTalk scripts that largely automate the process of calculating spin lattice relaxation times, which in the past was a tedious manual process. Separate scripts were developed for each of the major stages of the analysis process: display buffer, baseline, clear channels and FFT. Separating each of these functions makes it possible for us to quickly review the data at each stage of the analysis process in order to check for anomalies. The treatment, one-by-one or in batch format, of each of the system's responses was made literally to be "push-button" type, with the help of Origin's graphical interface and scripting ability.

The scripts dramatically increase analysis speed. Our measurements have continued to some direct NMR diffusion measurements (a different kind of measurement from "T1") which are very valuable in any study of the conductivity of a material. It is one matter to hook up leads across a sample and measure its total conductivity, but quite another to isolate the motion of individual atomic species within, as we are working to do. Again, Origin's organization is helping us do that.

 

 

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