Direct resolution

Nesbitt D J 1994 Fligh-resolution, direct infrared-laser absorption-spectroscopy in slit supersonic ]ets—intermolecular forces and unimolecular vibrational dynamics in clusters Ann. Rev. Phys. Chem. 45 367-99... 

Many experimental methods may be distinguished by whether and how they achieve time resolution—directly or indirectly. Indirect methods avoid the requirement for fast detection methods, either by detemiining relative rates from product yields or by transfonuing from the time axis to another coordinate, for example the distance or flow rate in flow tubes. Direct methods include (laser-) flash photolysis [27], pulse radiolysis [28]... 

Tsong, T, T. (1979). Quantitative atom-probe and field ion microscope studies at atomic resolution. Direct Imaging of Atoms in Crystals and Molecules Nobel Symposium 47, The Royal Swedish Academy of Sciences, 7-15. 

Comparison of the Optimized Density and Density/Temperature Separations. It is instructive to compare the results of the separations of the eight component mixture illustrated in Figures 6 and 10. Because a threshold CRF (CRF-4) was employed for both the density and density/temperature separations, the minimum resolution (directly related to Smjn) was similar as expected, with slight differences attributable to the (minor) errors in predicting solute retention. 

Vongvilai P, Angelin M, Larsson R, Ramstrom O (2007) Dynamic combinatorial resolution direct asymmetric lipase-mediated screening of a dynamic nitroaldol library. Angew Chem Int... 

Until quite recently the isolation of optically active seienoxides has been limited to those contained in steroids (isolated as diastereoisomeis). < The difficulty in obtaining these compounds was attributed to the racemization through the achiral hydrated intermediates. Simple optically active sel enoxides (S-11% ee) were first prepared by kinetic resolution. Direct oxidation of selenides to seienoxides was first reported using optically active oxaziridine derivatives under anhydrous conditions, but the extent of the asymmetric induction was somewhat unsatisfactory with methyl phenyl selenide as substrate (8-9% Recently much improved enantiomeric excesses (45-73%) were achieved with new oxaziridine reagents such as (70). An attempt at the asymmetric oxidation of more bulky selenides was independently carried out using Bu OCl in the presence of (-)-2-octanol (equation 55), but resulted in unsatisfactory enantioselectivities (ee 1%). Much better results were obtained by the oxidation of p-oxyalkyl aryl selenides (ee 18-40% equation 56) 27 gjyj selenides (ee 1-28%) using... 

In the subsequently developed techniques, the HSCCC effluent is directly introduced into the MS to preserve the peak resolution. Direct HSCCC-MS techniques have many advantages over the HSCCC-TSP method as follows ... 

The USP Convention membership, at its April 2000 Quinquennial Meeting, adopted resolutions directing USP to explore in the next 5 years ... 

Hansen MAE, Smedsgaard J. Automated work-flow for processing high-resolution direct infusion electrospray ionization mass spectral fingerprints. Metabolomics 2007 3 41-54. 

The CoE resolution directs QRM to the quality management system for preparation stating ... 

Of course, the objective is to resolve the solutes, not merely separate them, and Figure 4.10 tells us nothing about the degree of peak resolution that can be expected. The resolution will depend on the carrier-gas flow and the colunm physical parameters because the peak widths and thus the theoretical plate height influence the observed resolution. In order to characterize peak resolution across a range of column temperatures, we must either perform a series of experiments and measure resolution directly, consbuct an empirical mathematical model by fitting curves to a smaller dataset, or find a model that encompasses the additional variables and requires a minimum amount of experimental data. 

Very recently, a tuneable CO2 laser has been combined with an AFM to form an aperture-less nearfield imaging system to obtain contrast in infrared absorption on a scale of about 100 nm [299]. However, the tuneable range of the CO2 laser is limited to a region of the IR spectrum that is not particularly informative for most IR chromophores ( 2300 cm ). For many applications coupling of a tuneable IR diode laser to an infrared microscope [300] is more attractive. Hammiche et al. [301] have used a Wollaston resistive thermometer as a photothermal probe to record IR spectra of polymers. Anderson [302] has indicated that an AFM/FTIR microscope without specialised tips can provide surface topography and chemical mapping at high spatial resolution. Direct infrared detection at a surface with the use of an AFM was tested both with filter and FTIR spectrometers (Fig. 5.6). Nowadays, IR spectroscopy at... 

Carbon replicas [427] are formed by the evaporation of a thin layer of carbon in a vacuum evaporator. Metal shadowing, at an angle of 20 to 45° to the specimen surface is performed while the specimen is in the evaporator. The highest resolution direct replica material is carbon/platinum (C/Pt). After evap-... 

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