Tuning rods

The probe tuning rods are long extensions of the variable capacitors located at the top of the probe, near the probe coil. The capacitors are delicate and there are two ends of the travel of the knob If any force at all is applied at the end of the travel, the capacitor will break. This will usually require that the probe be sent back to the manufacturer for repair, a process requiring a week or two and costing many thousands of dollars. For this reason many NMR labs do not allow users to tune the probe ... 

Rod growth dynamics also depend upon the identity of the phosphonic acid. The effectiveness of the phosphonic acid in promoting rod growth depends critically on its steric bulk, or the length of its alkyl chain. Shorter-chain phosphonic acids, such as HPA, more effectively promote rod growth compared to longer-chain phosphonic acids, such as tetradecylphosphonic acid (TOPA). Combinations of longer-and shorter-chain phosphonic acids can be used to readily tune rod aspect ratios and control shape evolution dynamics. 

Fig. 9 Photograph of two narrowbore probeheads. a aluminium jacket sealing the double helix used for thermo stating b high pressure vessel c platform carrying the autoclave d capacitors e capacitor platforms f tuning rods g high pressure connector h thermocouple i BNC connector j Pt-100 connector k copper tubing and 1 widebore adapter.

Figure 2. Photograph of two narrowbore probeheads a) aluminum jacket sealing the double helix used for thermostating, b) high pressure vessel, e) platform carrying the autoclave, d) capacitors, c) capacitor platforms, f) tuning rods, g) high pressure connector, h) thermocouple, i) BNC connector, j) Pt-100 connector, k) copper tubing, I) widebore adapter.

A. Gole and C. J. Murphy, Biotin-streptavidin-induced aggregation of gold nanorods Tuning rod-rod orientation, Langmuir, 21(23), 10756-10762 (2005). 

In aqueous media, they assemble into spherical capsules capable of encapsulating Nile Red with remarkably low CMC values (2 x 10 M for G1 and 3 x 10 M for G2). Similarly, the size of the aggregate derived from a related dendron-rod-dendron copolymer, composed of a phenylene vinylene rod capped on each end by amphiphilic polyether dendrons, could be tuned in the melt state by modifying the generation level of the dendron (Fig. 11.28 Lee et al. 2002). 

Woolfson and coworkers described impressively the design of peptide fibers based on a-helical coiled-coil building blocks [107], By programming at the amino acid sequence level, the fibers could be fine-tuned from thick rigid rods to thinner,... 

Figure 5. phE (dark line) and PIE measured by a QMS tuned to mass 44 (light line) accompanying the fracture of fused silica rod in three point bend Time t = 0 is chosen to coincide with the onset of phE, which corresponds closely to the onset of fracture. (Reproduced with permission from Langford, S. C. Dickinson, J. T. Jensen, L. C. J. Vac. Sci. Technol. A. in press. Copyright 1989 American Vacuum Society.)... 

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