Instrument well-timed

Sometimes the so-called problem could just be an artifact of the instruments being used to characterize or test the converter. That can be really embarrassing to find out, especially after alerting everybody from Design to Production Backtracking too many times, especially in the course of a single day, can become a rather overwhelming declaration of incompetence. So it is extremely important we understand our instrumentation well. 

These studies also revealed the difficulty in transfer of training sets between different NMR instruments without some type of standardization to minimize spectral variation. In many instances large data sets may be compiled from individual NMR experiments run over several months (if not years), as well as data collected on different instruments and from different groups. There is no guarantee that the performance of an NMR instrument over time, or different NMR instruments, are equivalent. Gislason and co-workers have recently reported a study on the protocol for transferring PLS methods between low field process NMR spectrometers in which they found that a piece-wise direct standardization methods for accurate model transfer. This study appears to be one of the few concerning instrumental transfer of chemometric models in NMR. The development of efficient methods that allow for accurate transfer and combination of NMR spectral data from a variety of sources is an important area for future research. 

To place these developments in perspective, some account will be given of the invention of magnetic resonance methods for condensed matter and of the various types of apparatus that were available, especially for MR where there has been substantial improvement in instrumentation with time. (We shall abbreviate nuclear magnetic resonance by NMR" and electron paramagnetic resonance by "EPR". We prefer the latter designation to electron spin resonance, because electron orbital as well as spin moments may be involved.) Since many readers may not be familiar with the principles of magnetic resonance, qualitative explanations of basic aspects are included. Emphasis will be on work in the United States, but some contributions from elsewhere will be mentioned. 

In the case of the third requirement, instrument manufacturers have developed highly specialized Magnetic Sector mass filter-based instruments and time-of-flight mass filter-based instruments. Quadrupole mass filter-based SIMS instruments are ineffective in this area because of their inability to provide the high mass resolution required. Fourier Transform Ion Cyclotron Resonance (FT-ICR) as well as Orbitrap mass filter-based instruments, on the other hand, show significant promise. Mass filters are discussed in Section 4.3.2.I. 

The specific results of well over 1 year of continued monitoring will be discussed in a second paper. It is pointed out here that the AEBIL monitoring system installed in the power plant for the above monitoring purposes has efficiently and continuedly performed during this time interval, with no instrumentation reliability problems. 

We are confident that any user of this combined evaluation technique, as well as the development of future test standards for manual ultrasonic testing will benefit from this result, because it allows a greater flexibility in the applicable method without loosing reliability. Often an expensive production of a reference block can be avoided and therefore testing costs are reduced. Since all calculations are performed by a PC, the operator can fully concentrate on his most important duty scanning the workpiece and observing the A-scan. Additional time will be saved for the test documentation, since all testing results are stored in the instrument s memory (the PC s hard drive) with full link to the Software World (Microsoft Word, Excel, etc.). 

A microwave pulse from a tunable oscillator is injected into the cavity by an anteima, and creates a coherent superposition of rotational states. In the absence of collisions, this superposition emits a free-mduction decay signal, which is detected with an anteima-coupled microwave mixer similar to those used in molecular astrophysics. The data are collected in the time domain and Fourier transfomied to yield the spectrum whose bandwidth is detemimed by the quality factor of the cavity. Hence, such instruments are called Fourier transfomi microwave (FTMW) spectrometers (or Flygare-Balle spectrometers, after the inventors). FTMW instruments are extraordinarily sensitive, and can be used to examine a wide range of stable molecules as well as highly transient or reactive species such as hydrogen-bonded or refractory clusters [29, 30]. 

NMR spectroscopy is always struggling for increased sensitivity and resolution, as well as more efficient use of the instrument time. To this end, numerous improvements of the simple inversion-recovery method have been proposed over the years. An early and unportant modification is the so-called fast mversion recovery... 

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