Micro coil

For a manufacturer the difficulty is to estimate future developments or trends in NMR microscopy. Based on dedicated laboratory-made hardware developed by the NMR microscopy users and on their requests for new commercial hardware and software, the following topics could become more important micro-coil applications, multiple receiver systems and multi-coil arrangements, NMR microscopy at very high magnetic fields, MAS imaging and localized 1H MAS spectroscopy and localized single-shot 2D spectroscopy. There are no clear-cut distinctions between most of the individual topics, as will be discussed in the following sections. 

Micro-coils can be used to reach higher spatial resolutions, as a result of the increase in sensitivity of very small rf coils. The possible resolution in NMR... 

Fig. 2.1.13 Planar spiral micro-coil of 1.2 mm outer diameter (left), mounted as an exchangeable rf insert on a standard NMR microscopy probe (right) (Bruker-Biospin GmbH, Rheinstetten, Germany). The micro-coil is embedded, together with a glass sample holder, in a slotted PTFE holder.

A single cell layer of an excised piece of onion epidermis was selected as a test object for this micro-coil, (Figure 2.1.14), and an imaging experiment was carried out, similar to the one by Mansfield et al., who used a laboratory-made micro-coil probe and gradient system [31]. Other micro-coil types, e.g., volume coils or coils that are immersed into the objects, can be adapted to specific applications and mounted on commercial imaging probes. 

Motojima, S., Asakura, S., Kasemura, T., Takeuchi, S. and Iwanaga, H., Catalytic effects of metal carbides oxides and Ni single crystal on the vapor growth of micro-coiled carbon fibers, Carbon, 1996,34, (3), 289 296. 

Advances in micro-coil probes offer additional benefits in sensitivity for NMR detection of metabolites and are especially useful for mass limited samples (49-55). Apart from the small coil volume, their solenoidal geometry... 

Motojima S, Kagiya S, Iwanaga H (1996) Preparation of micro-coiled SiC and TiC fibres by vapour phase metallizing of micro-coiled carbon fibres. J Mater Sci 31 4641—4645... 

Motojima S, Hasegawa I, Iwanaga H (1995) Vapour growth of micro-coiled cermic fibres and their properties. J Phys IV 5 C5-1061—1068... 

Motojima S, Hamamoto T, Ueshima N, Kojima Y, Iwanaga H (1997) Preparation and properties of ceramic micro-coils by CVD process. In Allendorf MD, Bernard C (eds) Proceedings of the 14th international conference on chemical vapour deposition/Jointly held with the Euro CVD-11. Paris, France. Electrochemical Society, Pennington, NJ, pp433 139... 

Controlled delivery of all pushable fibered Micro coils (Cook, Boston Scientific and Cordis) 0.018 in. is possible by using a coaxial guide (4-6 F) and microcatheters [14]. In order to achieve cross sectional occlusion of the artery or vein, the micro coils must be delivered into a tight coil mass. To achieve this, a 0.016 pusher wire (Boston Scientific or Cordis) is used and the same weaving action is performed during deployment in order to nest/pack the microcoil into a tight coil mass (Fig. 3.3). 

The disadvantage of microballoon actuators is the low-step response. The other disadvantage is the plastic deformation of the membrane due to stretching at high load. The actuation can be based on micro coil, piezoelectric, electrostatic, and electromagnetic principle. 

The schematic of flap actuator is shown in Fig. 6. The actuator surface is supported at one end as cantilever support and the actuation takes place due to the external applied force at the other end. The disadvantage of micro coil, piezoelectric and electrostatic actuation is the large voltage requirement. Thus, the devices heat up leading to increase in temperature of the substrate with parasitic heat loss to the fluid. Magnetic... 

Kryostatschnitt micros coil condenser (Dimroth type... 

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