ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Structural Studies of a Series of Organic Non-Linear Optical Materials (1997)

Cole, J. C. ; Cole, J. M. ; Cross, G. H. ; [et al.]

Copenhagen : International Union of Crystallography (IUCr)

Acta crystallographica 53 (1997), S. 812-821

add to mindlist on the mindlist

Details

ISSN: 1600-5740

Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001

Topics: Chemistry and Pharmacology , Geosciences , Physics

Notes: The crystal structures of {4-[bis(diethylamino)methylium]phenyl}dicyanomethanide (I), {4-[cyano(4-methylpiperidyl)methylium]phenyl } dicyanomethanide (II), {4-[cyano(1-pyrrolidinyl)methylium]phenyl}dicyanomethanide (IV) and (Z)-{4-[1,3-dicyano-3-(diethylamino)-2-propenylium]phenyl} dicyanomethanide have been determined by X-ray crystallography. Together with (Z)-{4-[1-cyano-3-(diethylamino)-2-propenylium]phenyl}dicyanomethanide [(III): Cole, J. C., Howard, J. A. K., Cross, G. H. & Szablewski, M. (1995). Acta Cryst. C51, 715–718], these compounds exhibit varying degrees of quinoidal characteristics and yet have predominantly zwitterionic ground state character. The presence of high dipole moments in the crystal can thus be inferred and are substantiated by measurements of high solution-state dipole moments. Negative solvatochromism (hypsochromism on increasing solvent polarity) confirms the zwitterionic character in at least two of the series.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1107/S010876819601525X

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Characterisation of Epoxy Resins for Microstereolithographic Rapid Prototyping (1999)

Chatwin, C. R. ; Farsari, M. ; Huang, S. ; [et al.]

Springer

The international journal of advanced manufacturing technology 15 (1999), S. 281-286

add to mindlist on the mindlist

Details

ISSN: 1433-3015

Keywords: Key words.Diffractive optics; Four-wave mixing; Microstereo-lithography; Optoelectronics; Photochemistry

Source: Springer Online Journal Archives 1860-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: Two epoxy resins are investigated using non-degenerate fourwave mixing. The materials assessed are optimised for use with a UV argon-ion laser. The holographic gratings were written at a wavelength of l= 351.1 nm for an irradiance range 0.5–3.0 W/cm 2 and read at l= 632.8 nm in order to compare the reactivity, curing speed, shrinkage and resolution of the resins. These experiments were carried out to prove the suitability of the photopolymerisation systems for use with a new microstereolithographic technique. This new technique exploits a spatial light modulator to create 3D components using a completely planer, layer-by-layer, process of exposure which is described herein. With this procedure it is possible to build components with dimensions in the range of 50 mm to 50 μm, and feature sizes as small as 5 μm with a resolution of 1 μm.