macromolecular assembly, 1573 tungsten-halogen lamp, 1573 tunnelling, 1573 turbidimetric titration, 1574 turbidity, in light scattering , 1574 turnover frequency in catalysis , 1574 twisted intramolecular charge transfer, 1574 two-dimensional chromatography, 1574 two-photon excitation, 1575 two-photon photochromism, 1575 two-photon process, 1575 two-site immunoradiometric assay, 1575 ultimate capacity in solvent extraction , 1576 ultrafiltrate, 1576 ultrafiltration, 1576 ultrasonic detector in gas chromatography , 1576 ultraviolet, 1577 umpire sample, 1577 umpolung, 1577 unactivated adsorption process, 1578 uncertainty of measurement, 1578 uniaxial pressing, 1578uniaxial sample, 1578 unified atomic mass unit, 1578 uniform corrosion, 1579 uniform polymer, 1579 uniformly labelled, 1579 uniformly labelled tracer, 1579 unit cell, 1580 unit (item/portion/individual) in analytical chemistry , 1580 unit of measurement , 1580 unit system, 1580 universal calibration in chromatography , 1581 universal detector in chromatography , 1581 unperturbed dimensions in polymers , 1581 unreactive, 1581 unstable, 1581 unstable film, 1582 unstable ion in mass spectrometry, 1582 upconversion, 1582 upfield, 1582 uphill transport in membrane processes , 1583 upper critical solution temperature, 1583 upper limit of measurement in atmospheric trace component analysis , 1583 upstream in membrane processes , 1583 uptake, 1584 ureides, 1584 urethanes (urethans), 1584 uronic acids, 1584 uronium salts, 1585