Electro-optic polymers for high speed modulators

Different electro-optic polymer systems are analyzed with respect to their electro-optic activity, glass transition temperature (Tg) and photodefinable properties. The polymers tested are polysulfone (PS) and polycarbonate (PC). The electro-optic chromophore, tricyanovinylidenediphenylaminobenzene (TCVDPA),which was reported to have a highest photochemical stability [1] has been employed in the current work. Modified TCVDPA with bulky side groups has been synthesized, and a doubling of the electro-optic coefficient (r33) compared to the unmodified TCVDPA has been shown. The plasticizing effect of the chromophore, has been reduced by attaching it to the polymer backbone. SU8 (passive) and PC-TCVDPA (active) channel waveguides were fabricated by photodefinition technique and the passive waveguide losses were measured to be 5 dB/cm at 1550 nm

Photodefinable electro-optic polymers for high speed modulators

We present a series of polymeric electro-optic (EO) materials based on the tricyanovinylidenediphenylaminobenzene (TCVDPA) chromophore which exhibits an exceptionally high photostability combined with a high EO activity. The EO properties of these derivatives are given and the best result was obtained with the di-tBut derivative 2, which showed a nearly doubling effect of $r_{33}$ (14 pm/V to 25 pm/V), while increasing the concentration from 25 wt% to 37.5 wt%. A microring resonator design was made based on the PC-TCVDPA system. Waveguides were fabricated by photodefinition of inverted ridges in VSC, a negative epoxy based photoresist with low refractive index

Photodefinition of channel waveguide in electro-optic polymer

Polymers with optically active nonlinear chromophores have been shown to have a promising future in low cost and high speed electro–optic device applications. However, a main question of concern is the photochemical stability of the chromophores for long term application. The chromophore TCVDPA with a benzene bridge between a tricyanovinyl acceptor and an amino donor has been reported to have high photochemical stability combined with high electro-optic activity. In the current work direct waveguide definition of the host polymer SU-8, a negative photoresist, containing this chromophore by masked UV exposure followed by development, has been demonstrated. This was possible by utilizing the chromophore low absorption window in the UV region that allows crosslinking of the host polymer by exposing to UV light followed by thermal curing

Kinetic study of an on-chip isocyanate derivatization reaction by on-line nano-esi ms

A high-throughput method is presented for the study of reaction kinetics by nano- electrospray ionization mass spectrometry (nano-ESI MS). The reaction of propyl isocyanate (2), benzyl isocyanate (3), and toluene-2,4-diisocyanate (4) with 4-nitro-7- piperazino-2,1,3-benzoxadiazole (NBDPZ) (1) to yield the corresponding urea derivatives (5) was carried out in a continuous flow glass microchip. Real-time monitoring of the reactions was done by nano-ESI MS. Rate constants of 1.6 ␣ 104 M-1 min-1, 5.2 ␣ 104 M-1 min-1, and 2.5 ␣ 104 M-1 min-1 were determined for isocyanate 2, 3 and 4, respectively

Double and triple calix[4]arenis connected via the oxygen functions

New macrocyclic molecules are described containing two or three p-tert-butylcalix[4]arene subunits connected via their oxygen atoms. These macrocycles are available by two general methods which are capable of producing assemblies with bridges of varying rigidity and length

A transparent role of information systems within business processes: A case study

Service organisations still struggle with the adoption of a road to excellence. Evidence exists that processes and systems in service organisations are not always as advanced as in manufacturing organisations. Adding a quality smile to the face of the service provider will not solve the problems that are caused by defects in the underlying work processes and systems. Attention to the hardware in service organisations, i.e. to the service design, should instead create a more reliable process flow and time for the service staff to develop improvement activities and spend more time with customers. The way service organisations started to take excellence seriously is by making their processes transparent, eliminating undesired steps and deleting loops. In this paper the focus is on expanding this approach by adding information systems and information sources into a process map. This seems to be a promising approach for small and medium sized service organisations, without having to invest in expensive and rigid business process automation

The Organization of Two Soft (Cu2Ө, Ni2Ө) Metal Centers in Heterotrinuclear Complexes of a Macrocyclic Ligand by Cocomplexation with Ba2Ө

The short distances between the two transitionmetal centers in the trinuclear complexes 3 are caused by cocomplexation of Ba2Ө: Cu2Ө:...Cu2Ө 3.50, Ni2Ө ...Ni2Ө 3.42 Å. The macrocyclic ligand is formed as the complex 2 from o-phenylenediamine and 1 in the presence of Ba2Ө. Complexes 3, in turn, are obtained by treatment of 2 with copper or nickel acetate

Solvent systems containing diglycolamide-functionalized calix[4]arenes in room temperature ionic liquid for metal ion extraction: studies with simulated high-level wastes

The extraction of actinide ions such as Am(III), Pu(IV), Np(IV), U(VI) and Pu(VI) was studied from simulated high-level waste (SHLW) solutions using several diglycolamide-functionalised calix[4]arene (Calix-DGA) ligands dissolved in the room temperature ionic liquid (RTIL) [C8mim][NTf2]. The Calix-DGA ligands were three lower-rim functionalised ligands with varying alkyl substituents (L-I, L-II and L-III), an upper-rim functionalised ligand (L-IV) and an upper- and lower-rim functionalised ligand (L-V). The SHLW solutions used contained 0.5 M HNO3 and the extraction trend of the actinides was found out to be Am(III) > Pu(IV)∼Np(IV)≫ and the extraction efficiency of the Calix-DGA ligands for Am(III) being L-V>L-I>L-II>L-IV>L-III. Reasonably, good extraction of Am(III) was obtained with 5.0 × 10− 4 M ligand solutions suggesting that higher concentrations of the ligand can be used for a higher loading of the metal ions. The extraction of other metal ions representing fission products, structural materials and process chemicals was studied by Inductively Coupled Plasma –Atomic Emission Spectroscopy analysis. The extraction mechanism follows the cation-exchange mechanism often observed with RTIL-based extraction systems. Enthalpy changes were measured from van't Hoff plots and were found to be significantly different than those observed with tracer studies reported previously

Electrochemistry of potentially bioreductive alkylating quinones : Part 1. Electrochemical properties of relatively simple quinones, as model compounds of mitomycin- and aziridinylquinone-type antitumour agents

The influence of methyl-, hydroxy and amino substituents on the electrochemical behaviour of simple 1,4-naphtho-and 1,4-benzoquinones, model compounds of many quinoid antitumour agents, in aqueous media was studied. Significant changes in electrochemical behaviour were observed, potentially the result of a change in the electron density of the quinone moiety, pre- or post-protonation of substituents, hydrogen bond formation, tautomerization reactions and steric interactions between the quinone moiety and substituents. The information obtained was of benefit in the elucidation of the reduction mechanisms of quinoid antitumour agents such as aziridnylquinones and mitomycins