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BEng Mechanical Engineering 03/01/2012 Article 1 BEng Mechanical Engineering 1.

Muon-spin Rotation

1.1 Muon A muon is a spin-1/2 particle. A particle physicist would think of a positive muon as a lepton, a heavy anti-electron [1]. 1. We should think of it as a light proton. 2. When implanted in a solid, the muon behaves as a microscopic magnetometer. 1.2

Muon Spin Rotation

SR, which stands for Muon spin rotation. This technique is performed on a number of types of organic materials, including [1]: 1. Organic superconductors 2. Colossal magneto-resistive materials 3. Organic ferromagnets 4. Conducting polymers 5. Liquid crystals Muons are fired at the sample, and almost instantaneously implant at interstitial sites [1]. SR gives direct information about local magnetic fields, making the technique very useful for studying magnetic materials and superconductors [1]. 2.

Aharonov-Bohm effect

The Aharonov-Bohm, sometimes called the Ehrenberg-Siday- Aharonov-Bohm effect is a quantum mechanical phenomenon by which a charged particle is affected by electromagnetic fields in regions from which the particle is excluded.The earliest form of this effect was predicted by Werner Ehrenberg and R.E. Siday and was later rediscovered by Aharonov and Bohm. The effect was predicted to arise from both magnetic fields and electric fields, but the magnetic version was easier to observe [2]. The most commonly described case is the Aharonov-Bohm solenoid effect; the wave function of a charged particle passing around a long solenoid experiences a phase shift [2]. This phase shift has been observed experimentally by its effect on interference fringes. 3.

Polymer-based devices for optical communications

3.1 Polymers Polymers are emerging as new alternative materials for optical communication devices. Two types of polymer-based devices for optical communications were developed [2]. One type is for ultra high-speed signal processing that uses nonlinear optical (NLO) polymers in such devices as electro-optic (EO) Mach-Zehnder (MZ) modulators and EO 2x2 switches [2]. The other is for

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BEng Mechanical Engineering 03/01/2012 WDM optical communications that use low-loss optical polymers in such devices as 1x2, 2x2, 4arrayed 2x2 digital optical switches (DOSs) and 16 x16 arrayed waveguide grating (AWG) routers [2]. 4.

Electro-static Micro Motors

4.1 Electro-static In electrostatics, charge need not be 'static' in the sense of unchanging. Instead 'static' implies that the dynamic coupling between electric and magnetic fields can be ignored. In electrostatics we study e-fields, voltage, and charge, but ignore any magnetic fields generated by the motion of these charges [2]. 4.2 Micro motors By analyzing several aspects of performance, including energy density, force density, size, constraints on motor-drive circuitry, motor topologies, and friction, we can prove that electrostatic machines have advantages as microfabrication processes achieve finer resolution, and, in fact, can exceed the energy and force density capabilities of conventional magnetic machines at small enough scales [3]. 4.3 Advantages of micro motors 1. In micro domain, the effect of electrostatic force is larger than that of electromagnetic force. 2. Electrostatic micro motor has a higher power per unit volume and efficiency. 3. Its structure is simple; it can be made sufficiently small. References: 1. Muon-spin Rotation [2005] available from: http://users.ox.ac.uk/~sjb/musr/musr.html 2. Aharonov-Bohm [2005] available from: http://md1.csa.com/Journal. 3. Electro-static Micro Motors [2006] available from: http://www.ieee.org/portal/site

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