Flexing motion

Second, since neither rotation about the C2-C3 bond nor ring flexing motion can be effected and the P-endo hydrogen (H) at C3 cannot be forced to a 180° dihedral angle with respect to chlorine (Cl) at C2, only syn (cis or suprafacial) is possible. 

Slender spirochaetes often exhibit a flexing motion and this may be the result of a twisting of the protoplasmic cylinder, produced in reaction to the... 

Piezoelecttic impulse ink-jet printers ate especially sensitive to bubbles in the ink. A bubble in the firing chamber absorbs some of the comptessional force from the flexing of the chamber wall and reduces drop volume and drop velocity, thereby affecting print quaHty. Because of the limited range of motion of the crystal, bubbles ate not readily ejected, and the loss of print quaHty owing to their presence is persistent. 

Oil-canning The property of a panel that flexes past a theoretical equilibrium point, and then returns to the original position. This motion is analogous to the bottom of a metal oilcan when pressed and released. Part flexing can cause stress, fracturing, or undesirable melting of thin-sectioned, flat parts. 

A nonlinear molecule consisting of N atoms can vibrate in 3N — 6 different ways, and a linear molecule can vibrate in 3N — 5 different ways. The number of ways in which a molecule can vibrate increases rapidly with the number of atoms a water molecule, with N = 3, can vibrate in 3 ways, but a benzene molecule, with N = 12, can vibrate in 30 different ways. Some of the vibrations of benzene correspond to expansion and contraction of the ring, others to its elongation, and still others to flexing and bending. Each way in which a molecule can vibrate is called a normal mode, and so we say that benzene has 30 normal modes of vibration. Each normal mode has a frequency that depends in a complicated way on the masses of the atoms that move during the vibration and the force constants associated with the motions involved (Fig. 2). 

In the glassy amorphous state polymers possess insufficient free volume to permit the cooperative motion of chain segments. Thermal motion is limited to classical modes of vibration involving an atom and its nearest neighbors. In this state, the polymer behaves in a glass-like fashion. When we flex or stretch glassy amorphous polymers beyond a few percent strain they crack or break in a britde fashion. 

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