Field widening

Studies of atmospheric properties using IR spectroscopy techniques have been reported in the literature for nearly 100 years. This paper presents a brief historical review of the development of this area of science and discusses the common features of spectrographic instruments. Two state of the art instruments on opposite ends of the measurement spectrum are described. The first is a fast response iri situ sensor for the measurement of the exchange of CO2 between the atmosphere and the earth s surface. The second is a rocketborne field-widened spectrometer for upper atmosphere composition studies. The thesis is presented that most improvements in current measurement systems are due to painstakingly small performance enhancements of well understood system components. The source, optical and thermal control components that allow these sensors to expand the state of the art are detailed. Examples of their application to remote canopy photosynthesis measurement and upper atmosphere emission studies are presented. 

Rocketborne Field-Widened Interferometer-Spectrometer. The rocket-borne field-widened interferometer-spectrometer (RBFWI) is an example of an instrument that uses emission techniques to make broad-band spectral measurements in the 2 - 7.5 pm spectral region in the upper atmosphere. Figure 10 illustrates the concept of this cryogenically-cooled instrument developed at Utah State University under an Air Force Geophysics Laboratory contract. 

Figure 12. Theoretical maximum solid angle for a standard Michelson system as a function of resolving power compared to field-widened interferometer operating point.

Table I. Rocketborne Field-Widened Interferometer-Spectrometer...

The Field Widened interferometer spectrometer described herein was developed under a contract from the Air Force Geophysics Laboratory. We acknowledge the major contributions of Ralph Haycock, Alan Thurgood and Val King of Utah State University in the sensor development and of Ron Straka of AFGL for contract support. The authors especially wish to thank Glenn Allred for his role in editing this paper. 

G.C. Kennedy, suggesting that the quadruple point (gypsum—anhydrite— bassanite—H2O) is near 600 MPa (6 kbar) and 130°C, with the bassanite field widening in temperature at higher pressures. Zen (1965) estimated from thermochemical calculations and chemographic analysis that the quadruple point should be near 900 MPa (9 kbar) and 170°C. Solubility and phase-transformation experiments (Zen, 1965 Kinsman, 1974) indicate that bassanite is metastable at 0.101 MPa (1 atm.) and temperatures of 25—70°C. The conclusion of Goodman (1957) from petrographic examination that... 

Derivatization or polymerization of CDs open new fields, widening considerably the application possibilities limited by the factors mentioned in the previous points. 

Figure 5.24. Field-widened interferometer designed by Bouchareine and Connes [29]. The movable rear-silvered mirror is translated in a direction perpendicular to that of a conventional Michelson interferometer, so that the OPD is increased by increasing the distance traveled through the prism. (Originally reproduced from [29], by permission of the author.)...

The preparation of 5-ACETYL-l,2,3,4,5-PENTAMETHYLCYCLO-PENTADIENE is of value in the synthesis of pentamethyleyclo-pentadiene and many pentamethylcyclopentadienyl metal carbonyl derivatives that are more soluble in organic solvents than those derived from cyclopentadiene. Simple preparations of 5,6-DIHYDRO-2-PYRAN-2-0NE and 2-//-PYRAN-2-ONE make these hitherto rather inaccessible intermediates available for cycloaddition and other reactions. The already broad scope of the Michael reaction has been widened further by including an efficient preparation of ETHYL (E)-3-NITROACRYLATE. Workers in the field of heterocyclic chemistry will find a simplified method for the preparation of 2,3,4,5-TETRA-HYDROPYRIDINE of help. 

The development and the recent increase in availability of the scanning electron microscope with its considerable depth of field and reduced beam intensity has widened the range of samples which can be examined... 

The occurrence of the moganite-type phase in PON confirms that moganite is really a new structure type in AX2 compounds. The molar volumes at ambient of the three phases, cristobalite, moganite, and quartz (22.58, 21.05, and 20.64 cm3, respectively) follow the same trend as in silica. The smaller size of the P02N2 tetrahedron relative to that of Si04 (cf. Table VI) widens the pressure fields of stability, so that PON appears to be very useful to shed light on the detailed behavior of silica, which is still ill defined. 

These and several other researchers extended the methodology with the aim to widen functionality, using dopant molecules and silicon precursors derivatized with organic moities giving place to a vast class of hybrid organic-inorganic organosilica nanocomposites capable to meet numerous, advanced requirements in fields as diverse as catalysis,... 

The various special ENDOR techniques summarized in Sect. 4 widen the field of applications considerably. They allow investigations either of complex, oriented spin systems, or of paramagnetic centers in randomly oriented large molecules. The ENDOR techniques are particularly useful to study biochemical systems, which are often characterized by very poorly resolved powder EPR spectra. 

---