The Colloid Chemical Approach to Nanostructured Materials

http://kristiankjaer.dk/krkj/Some_Publications/Principles_GIXD_n_Monolayers_Air-Water__PhysRep_vol_246_p_251-313_1994.pdf

Principles and applications of grazing incidence X-ray and neutron scattering from ordered molecular monolayers at the air-water interface

Design and characterization of crystalline thin film architectures at the air-liquid interface: simplicity to complexity.

Langmuir monolayers to study interactions at model membrane surfaces

Langmuir-Blodgett films

We have used synchrotron radiation to study organic monolayers on water (''Langmuir films''). At high monolayer pressures, lead stearate (Pb(C/sub 17/H/sub 35/COO)/sub 2/) shows a powder peak at 1.60 A/sup -1/, implying an area per unit cell of 17.8 A/sup 2/ if the lattice is triangular. The correlation length is about 250 A. Lignoceric acid (C/sub 23/H/sub 47/COOH) shows a similar peak even though no heavy ions are attached. When the pressure is reduced, the peak in lead stearate does not observably move or broaden; below the ''knee'' in the isotherm, however, the peak height decreases slowly with increasing area, implying a first-order melting transition.

X-ray diffraction studies of organic monolayers on the surface of water.

SINTER‐FORGED YBa2Cu3O7‐δ

High T{sub c} ceramic superconductors, as exemplified by YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, have recently gained widespread interest in the scientific community. To date, the preparation of this and related materials in powder form has involved, with few exceptions, solid state reaction techniques. The resulting equilibrated powders, which are rather unsinterable, have typically been formed into pellets and fired for subsequent physical measurements. The densities of such pellets are considerably below the theoretical prediction, and the development of more effective sintering processes would clearly be of great importance. In this communication the authors report a technique (sinter-forging) whereby nearly theoretically dense (>95% TD) samples of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} can be produced. Physical measurements revealed strong texturing and preferred crystallite orientation as well as significant anisotropy in the charge transport.

P. Georgopoulos

Papers

X-ray diffraction studies of organic monolayers on the surface of water.

SINTER‐FORGED YBa2Cu3O7‐δ

Sinter-forged YBa sub 2 Cu sub 3 O sub 7-. delta