Magnetic techniques

Another magnetic technique for the detection of free radicals uses an ordinary NMR instrument. It was discovered that if an NMR spectrum is taken during the course of a reaction, certain signals may be enhanced, either in a positive or negative... 

Safarikl. and Safarikova, M. (1999) Useof magnetic techniques for the isolation of cells. Journal of Chromatography B, 722 (1-2), 33-53. 

Hertzog, B.A., and Mathiowitz, E., Novel Magnetic Technique to Measure Bioadhesion. In Bioadhesive Drug Delivery Systems (E. Mathiowitz, D.E. Chickering, III, and C.-M. Lehr, eds.), Marcel Dekker, Inc., New York, 1999, pp. 147-173. 

PuP amongst compounds of metallic character, plutonium pnictides PuP, PuAs, PuSb are ferromagnetic. PuP has been studied not only by the magnetization technique but also by neutron diffraction specific heat and Powder polarized neutron... 

Another magnetic technique for the detection of free radicals uses an ordinary nmr instrument. It was discovered144 that if an nmr spectrum is taken during the course of a reaction, certain signals may be enhanced, either in a positive or negative direction others may be reduced. When this type of behavior, called chemically induced dynamic nuclear polarization145 (CIDNP), is found in the nmr spectrum of the product of a reaction, it means that at least a portion of that product was formed via the intermediacy of a free radical.146 For example, the question was raised whether radicals were intermediates in the exchange reaction between ethyl iodide and ethyllithium (2-39) ... 

Matsunaga (15) applied the magnetic techniques of Eischens and Selwood and the chemisorption and chemical techniques of Voltz and Weller to a series of chromia-alumina catalysts. He found that in the limit of low chromia contents, where Eischens and Selwood deduced a two-dimensional distribution of chromium ions, treatment with oxygen at 450°C. resulted in an average valence number of six for all of the chromium ions in the sample. 

Thermal GLC Diffusion Condensation Sorption GSC Sorption Volatili- zation LLC Distilla- tion Extraction LSC Ppt1 n Electro-deposition Crystallization Ring Oven Subli- mation Soln. Zone Refining Sieving Magnetic Techniques... 

Levine, S. (1856) Magnetic techniques for in vitro isolation of leucocytes, Science 123, 185. 

A new rapid mid-infrared spectroscopic method called diffuse reflectance infrared Fourier transform spectra (DRIFTS), coupled with chemometrics, has been developed by Janik, Merry, and Skjemstad (1998) and routinely applied to rapidly screen and compare crime scene samples (Figure 1.1). Added to these rapid methods and techniques are the use of rapid mass and volume magnetic susceptibility methods, which should also always be used before moving to the more costly methods (Figure 1.1). Mineral magnetic techniques are a relatively recent development (post-1971) and have now become a very powerful and widely used research tool to characterize natural materials in landscapes (e.g., Thompson and Oldfield 1986). 

It should be noted that the intermediate state was detected by a magnetic technique in MWO4 [13], and by a magnetooptical one in dysprosium orthoferrite [11]. 

The theory for the interpretation of the spectral properties of cobalt(II) is essentially known6-9, but no extensive compilation of experimental data is to our knowledge available. We want to fill this gap in the literature giving a comprehensive review of the ligand field interpretation of the electronic structure of high spin cobalt(II) complexes, as well as of the most common spectral and magnetic techniques which are used to characterize cobalt complexes. 

Another interesting example concerning exciton dynamics was also described by Kim and Weissman (83,84). They applied the transient magnetization technique to the study of the photoexcitation of phenazine doped with anthracene. In this system photo-excitation in the phenazine absorption region leads to a selectively populated phenazine triplet exciton which transfers the excitation to anthracene with conservation of polarization (27). The authors emphasized that the time dependence of the transient response requires further analysis, which must include an adequate quantum theoretical treatment on the evolution of the system shortly after excitation. One can expect that future refinement of this technique will lead to more exciting studies of the dynamics of triplet states and excitons in solid state. 

Williamson s magnetic technique employs a cylindrical Dewar filled with liquid helium, inside of which are the SQUID, which gauges the magnetic field, and another key... 

One task a chemist often handles is the separation of the components of a mixture based on one or more physical properties. This task is similar to sorting recyclable materials. You can separate glass bottles based on their color and metal cans based on their attraction to a magnet. Techniques used by chemists include filtration, which relies on particle size, and distillation and evaporation, which rely on differences in boiling point. 

Several polydentate N-ligands were shown to make macrocyclic poly aza complexes in the supercages of FAU-typc zeolites [7, 48]. In order to fully understand the coordination chemistry of Ni2 and Co2+, ESR, UV-VIS-NIR, Raman, and magnetic techniques were applied. The formation of [Co(II)cyclam]Y is clearly established, the cis... 

There are two magnetic techniques that can lead to particle size or particle size distribution one is a static method whereas the other is a resonance one. 

Deposits of metals from the vapor phase [2, 5, 6, 10] are especially useful for studies of very pure materials, where it is desired to correlate the structure and the electronic state of a solid with its catal3d ic activity. Metal deposits can be investigated by electron diffraction, conductivity measurements, and optical and magnetic techniques even while they are covered with a layer of adsorbed material or while actually participating in a catalytic process. 

---