Materials Literature
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The Ericksen-Leslie theory In this chapter we shall discuss the continuum theory of nematic liquid crystals and some of its applications. Many of the most important physical phenomena exhibited by the nematic phase, such as its unusual flow properties or its response to electric and magnetic fields, can be studied by…
Optical properties The unique optical properties of the cholesteric phase were recognized by both Reinitzer and Lehmann at the time of their early investigations which culminated in the discovery of the liquid crystalline state. When white light is incident on a ‘planar’ sample (whose optic axis is perpendicular to th…
This is a new and greatly revised edition of Professor Chandrasekhar's classic book Liquid Crystals, first published in 1977. The subject of liquid crystals has grown into an exciting interdisciplinary research field with important practical applications. This book presents a systematic and self-contained treatment of…
The degradation of the electrochromic film of a-WO<SUB>3</SUB> was investigated from the equilibrium state of different driving voltage and the time dependent emf was also obtained in an open or short circuit of zero volts. Based on the mechanism of activation and the principal of chemical reaction kinetics, the corre…
SiO2 thin films (1000-Å thick) were sputter deposited on GaAs substrates as a buffer layer in order to alleviate a thermal mismatching problem between ZnO films and GaAs substrates. Thermal stability of sputter-deposited ZnO films (0.5–2.0 μm thick) was tested on such a buffered GaAs substrate with a postdeposition he…
It is argued that the optical conductivity of face-centred icosahedral (FCI) quasi-crystals is dominated by band-structure effects. What makes FCI quasi-crystals different from conventional metallic alloys is the high multiplicity (namely, 42) of their reciprocal lattice vectors, which allows a better match between th…
Visible electroluminescence (EL) has been obtained from porous silicon cathodically biased in an aqueous electrolyte containing either the persulphate or the peroxide ion. EL efficiencies of up to 0.1% have been obtained from porous silicon formed on both n-type and p-type substrates for the application of only a few…
Evidence is presented, through high-resolution electron microscopy images, for the open-end growth of carbon nanotubes. Terminations of incomplete layers of carbon, seen on the tube surfaces and cone tips, suggest that the extension and thickening of the tubes occur by the island growth of graphite basal planes on exi…
The elastic modulus E of diamond is often set equal to 1/s<SUB>11</SUB> equals 1050 GPa, which assumes that is does not vary much with orientation, and many authors use (upsilon) equals 0.2 as an appropriate average value of Poisson's ratio, which is incorrect. In fact, since the elastic constants of diamond are known…
Nickel metal catalysts composed of nanometer by micrometer strips have been produced with solid-state microfabrication techniques. The strips are actually the edges of nickelcatalyst thin films, which are sandwiched between separating support layers, which are also nanometers thick. These linear nanostructures constit…
Photoluminescence spectroscopy studies of low energy erbium and erbium/oxygen-implanted silicon-nitride waveguides are compared. Emission spectra show peaks at 1533 and 1548nm. The optimum annealing temperature is determined to be 1175°C, yielding lifetimes up to 7ms and a several decade intensity increase. Er implant…
Differential scanning calorimetry and x-ray diffractometry have been used to monitor reactions of the C15 Laves phase GdCo2 during constant-rate heating in a hydrogen atmosphere and to determine the enthalpy change of each reaction. The values of the enthalpy change ΔH of hydrogen absorption, hydrogen-induced amorphiz…
The decomposition of two dilute Cu–Co–Ti alloys is investigated by resistivity measurements, transmission electron microscopy, and analytical scanning transmission electron microscopy. The Cu–1%CoTi alloy shows a quasi-binary behaviour. Even after annealing at 950°C and quenching, “primary” CoTi precipitates are prese…
Pulsed laser irradiation is used to heat deeply buried damage layers in diamond. Over a small range of laser powers, damage annealing, formation of buried graphitic layers, and melting of diamond followed by its conversion upon cooling into graphite are observed. The diagnostics employed are channeling contrast micros…
We have studied and compared the optical properties of both porous Si and the chemically synthesized planar and cubic Si skeleton clusters. Broad photoluminescence with large Stokes shifts were observed at the visible region in both samples. Spectroscopic analysis suggests that the surface of porous Si is similar to a…
Reflection high-energy electron diffraction oscillations during pulsed laser ablation of ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathit{x}}$ on ${\mathrm{SrTiO}}_{3}$(100) substrates were measured. We have found for the first time that the oscillations are modulated by the laser-…
The (2\ifmmode\times\else\texttimes\fi{}1) reconstruction of the (111) surface of diamond has been characterized via a series of first principles molecular dynamics calculations. The reconstructed clean surface is found to consist of dimerized \ensuremath{\pi}-bonded chains with no buckling and to be stable against th…
The mixed ferrite Cu1−xTixFe2O4 (where x = 0 to 0.7) are prepared by the ceramic method. X-ray diffraction and IR absorption spectra in the range from 200 to 1000 cm−1 are used for analysing the compositions. It is observed that samples with x ≦ 0.4 exhibit spinel phase, whereas for x > 0.4 mixed phases of spinel and…
We have investigated the generation of the pretilt angles for nematic liquid crystal (5CB) aligned in the cells using rubbed polyimide (PI) films containing trifluoromethyl moieties as a function of rubbing strength (RS). In order to characterize the films, we have conducted an analysis of the surface atomic concentra…
252Cf plasma desorption mass spectrometry has been used in the characterization of more than 100 synthetic porphyrins ranging in mass from 614 u for tetraphenylporphyrin to over 2000 u for some porphyrin model systems. In virtually every case, 252Cf plasma desorption mass spectrometry yielded an intense ionized molecu…