The London printings of the Chilean postage stamps between 1853 and 1862 were examined using analytical instruments available at the Smithsonian Institution. There are four broad major technical areas important to philatelic research: color science (colorimetry and luminescence), paper chemistry (composition, thickness, and roughness), ink chemistry (pigment and binder composition), and printin...

This paper describes the fabrication of polymer stamps using DNA nanostructure templates. This process creates stamps having diverse nanoscale features with dimensions ranging from several tens of nanometers to micrometers. DNA nanostructures including DNA nanotubes, stretched λ-DNA, two-dimensional (2D) DNA brick crystals with three-dimensional (3D) features, hexagonal DNA 2D arrays, and trian...

A technique for microcontact printing of thiols in liquid media is presented. Elastomeric poly(dimethyl siloxane) stamps are used to pattern gold surfaces with thiol-based self-assembled monolayers. The liquid (water in this case) has been used as an incompressible support and, advantageously, also acts as a medium in which alkylthiol ink molecules are poorly miscible. Consequently, we have bee...

The technique of electronic time-stamping allows a client to get an electronic proof of the existence of a document at a specific point in time. A simple way to achieve this is to produce a digital signature over the pair (document,time). Linked time-stamps have an advantage over these simple time-stamps because they construct a verifiable link between time-stamps. In this paper, we discuss how...

Time stamps are frequently used in multi-threaded applications, and provide a way for an application to determine order between events. We identify interactions between time stamps and transactional mechanisms that differ from the expected behaviour of using locks for mutual exclusion, and draft implementations that remove these differences.