Phase recording

Diphenyl-l,3,4-oxadiazole crystallization revealed two polymorphic forms (centrosymmetric and non-centrosymmetric) of the substance. Raman spectra of both phases recorded between 15 and 1700 cm-1 showed well-resolved internal modes and the external lattice vibrations below 200 cm-1, offering a fast tool for discrimination between different polymorphs. The internal modes were dominated by two groups, one around 1000 cm-1 and the second one between ca. 1500 and 1600 cm-1 <2003JST219>. 

Solutions and precipitates were analyzed on a Beckman Spectra-Span VI direct current plasma emission spectrophotometer (DCP), Precision for the Ca2 + analyses was 3% and for the Ba2 + 2% except for the most dilute samples In which It rose as high as 5%. Calcite mineralogy was determined on a Philips x-ray diffractometer calcite was the only phase recorded except In speed runs of under one hour In duration (not Included In this study) which produced vaterite. Details of analytic procedures are available In Pingitore and Eastman (30,31). 

Procedure Transfer 2.00 mL of each sample to separate test tubes, and equilibrate in the 37° water bath for at least 10 min. At the same time, equilibrate the Substrate Solution in the same water bath. At zero time, transfer 2.0 mL of the equilibrated Substrate Solution to the first sample tube, mix thoroughly, and return the tube to the 37° bath. Repeat the process for each sample. After exactly 30.0 min, transfer the test tube to a boiling water bath for 15 min, then remove and cool to room temperature. Add approximately 100 mg of Amberlite MB-1 Ion Exchange Resin to each tube, place the tubes on the shaker, and mix for at least 15 min. Filter the treated solution through a 0.45-p.m filter. Use a separate filter for each sample. Inject a 5-p.L portion of each filtered sample into a previously equilibrated high-performance liquid chromatograph equipped with an HPX 87C column (Biorad, or equivalent) and a differential refractometer. Filtered, degassed water is the mobile phase. Record the elution curve. 

Measurements made by using those solid detectors are conducted in three distinct phases recording, reading and erasing. This separation in different... 

Figure 12.8 STS spectra of tetracene/Ag(l 11), a-phase, recorded at two different positions inside the molecule.

Before developing a description of the clathrate synthesis mechanism we first note the large unit cell volume expansion for the NaSi Zintl phase recorded between 60 and 500 °C (Fig. 4.3). The thermal expansion coefficient has a remarkably high value (4.54 x that is comparable with ionic con-... 

If the sample (solution or mixture) is known to contain water, then not only should this information be recorded but also extreme care must be taken to ensure that the sampling method is compatible with water being present. Comments are provided in Section 5 regarding the removal of water and other volatile materials that can interfere with an analysis. Also, if a sample is seen to be made up of more than one phase, it is helpful to obtain spectra from each separated phase. Techniques such as filtration, decanting, and centrifuging should be used if practical to ensure representative sampling of a particular phase. Record the nature of the phase being... 

Fig. 26. Mo(llO) p(2x2) O. HREELS data for the Mo(llO) p(2x2)0 phase recorded for a crystal temperature T=110 K. The RW, the L-mode and the dipole active surface resonance are depicted as triangles, circles and diamonds, respectively. The solid triangles and the dots along (F H ) were measured with...

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