Magnetic alignment

Barium carbonate of finely controlled particle size reacts in the soHd state when heated with iron oxide to form barium ferrites. Magnetically aligned barium ferrite [11138-11-7] powder can be pressed and sintered into a hard-core permanent magnet which is used in many types of small motors. Alternatively, ground up magnetic powder can be compounded into plastic strips which are used in a variety of appHances as part of the closure mechanism. 

Lowik D, Shklyarevskiy 10, Ruizendaal L et al (2007) A highly ordered material from magnetically aligned peptide amphiphile nanofiber assemblies. Adv Mater 19 1191-1195... 

Fischer, J. E., Zhou, W., Vavro, J., Llaguno, M. C., Guthy, C HaggenmueDer, R., Casavant, M. J., Walters, D. E. and Smalley R. E. (2003) Magnetically aligned single wall carbon nanotube films Preferred orientation and anisotropic transport properties./. Appl. Phys., 93, 2157-2163. 

Nieh MP, Raghunathan VA, Glinka CJ, Harroun TA, Pabst G, Katsaras J (2004) Magnetically alignable phase of phospholipid bicelle mixtures is a chiral nematic made up of wormlike micelles. Langmuir 20 7893-7897... 

Prosser RS, Hwang JS, Void RR (1998) Magnetically aligned phospholipid bilayers with positive ordering a new model membrane system. Biophys J 74 2405-2418... 

Alignment of CNTs markedly affects the electrical properties of polymer/CNT composites. For example, the nanocomposites of epoxy/MWCNTs with MWCNTs aligned under a 25 T magnetic field leads to a 35% increase in electric conductivity compared to those similar composites without magnetic aligned CNTs (Kilbride et al., 2002). Improvements on the dispersion and alignment of CNTs in a polymer matrix could markedly decrease the percolation threshold value. 

The advent of very high fields has allowed the observation of the magnetic alignment of proteins with the magnetic field, which has the potential of giving further information on mobility.63... 

Figure 4. X-ray fiber diagrams of ethoxy-substituted, hexamethylene-spacer poly(ester). a, Before magnetic alignment b, after magnetic alignment and c, fiber. Sample-to-film distance, 4.7 cm.

Chemical shifts can also vary within a molecule for instance, ethanol (CH3CH2OH) exhibits three proton NMR resonances and two 13C resonances. The lines in the proton NMR spectrum of ethanol are further split by spin-spin coupling ,/. When magnetic nuclei are close to each other in a molecule, the magnetic field at one nucleus is affected by the magnetic alignment of the others (see Fig. 3.5). Spin-spin coupling can reveal much detailed information about the relative positions of different nuclei in a molecule. 

Matthews MJ, Dresselhaus MS, Dresselhaus G, Endo M, Nishimura Y, Hiraoka T, Tamaki N. Magnetic alignment of mesophase pitch-based carbon fibers. Appl Phys Lett 1996 69 430-432. 

Attachment of magnetic nanoparticles to antibodies that label specific proteins, as shown in Fig. 8.6, is now a possibility [17], Once the particles bind to proteins through highly specific antibody protein complementarity the entire nanoassembly becomes magnetically aligned in the presence of an external magnetic field ... 

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