PROPERTIES OF POLYURETHANE ELASTOMERS PREPARED FROM 1,1''''-ISO-PROPYLIDENE BIS(p-PHENYLENE-OXY) DI-PROPANOL-2, A POLYETHER (OR POLYESTER). AND 4, 4''''-DIPHENYLMETHANE DIISOCYANATE (MDI) BY ONE-STEP REACTION METHOD

Two new types of block polyurethane elastomers were prepared using two polyols polyethyleneadipate and PTHF respectively, and diisocyanate MDI extended with Dianol-33 (a new extender),by one step reaction and casting method. The properties of these polyurethane were studied by employing Instron infrared spectroscopy,DSC and wide angle X-ray diffraction etc.     

Functionalized heteropolyanions: high-valent metal nitrido fragments incorporated into a Keggin polyoxometalate structure

Three examples of nitrido-functionalized polyoxometalate species are reported, namely (n-Bu4N)4[PW11O39(OsN)] (1), (n-Bu4N)4[PW11O39(ReN)] (2), and (n-Bu4N)3[PW11O39(ReN)] (3), which feature the incorporation of [OsVI identical to N]3+, [ReVI identical to N]3+ and [ReVII identical to N]4+ fragments, respectively, into the framework of a Keggin-type heteropolyanion.     

Quasi-solitonic behavior of self-written waveguides created by photopolymerization

We investigated the condition of unique self-written channel and multichannel propagation inside bulk photopolymerizable materials. Light was introduced in the medium by a single-mode optical fiber. At a very low beam power of 5 muW , a unique uniform-channel waveguide without any broadening was obtained by polymerization. When the input power is increased to 100 muW , the guide becomes chaotic and multichannel. We connected two fibers separated by a 1-cm distance. The results open the door to studies of the optical and electro-optical properties of photopolymerized guides doped by nonlinear optical chromophores and to possible applications in integrated optical devices.     

The six principles for effective OR—Their relevance in the 90s

In 1974 in the UK, at a time of perceived anxiety in the OR community, the author enunciated six principles with the aim of helping to ensure the effectiveness, and thus survival, of in-house OR teams. The present paper explains the thinking on which these principles were based and explores how far they have stood the test of time, as well as their relevance today in a very different environment.     

Nuclear magnetic resonance study of In115 in B2-type PdIn

NMR measurements on In¹¹⁵ in B2-type PdIn from RT to 4.2°K are reported The low Knight shift is attributed to a reduction of the amount of s- character in wave functions at the In sites and not the density of states at the the Fermi level. The existence of a localized moment is considered.     

Effect of optical disorder and single defects on the expansion of a Bose-Einstein condensate in a one-dimensional waveguide

We investigate the one-dimensional expansion of a Bose-Einstein condensate in an optical guide in the presence of a random potential created with optical speckles. With the speckle the expansion of the condensate is strongly inhibited. A detailed investigation has been carried out varying the experimental conditions and checking the expansion when a single optical defect is present. The experimental results are in good agreement with numerical calculations based on the Gross-Pitaevskii equation.     

Bose-Einstein condensate in a random potential

An optical speckle potential is used to investigate the static and dynamic properties of a Bose-Einstein condensate in the presence of disorder. With small levels of disorder, stripes are observed in the expanded density profile and strong damping of dipole and quadrupole oscillations is seen. Uncorrelated frequency shifts of the two modes are measured and are explained using a sum-rules approach and by the numerical solution of the Gross-Pitaevskii equation.     

Control of the refractive index in photopolymerizable materials for (2+1)D solitary wave guide formation

We report an experimental and theoretical study on the optimization of (2+1)D self-written waveguide formation inside a photopolymerizable material. The accurate control of the refractive index value inside the bulk of the material during the polymerization process gives us the opportunity to define a virtual core and a virtual cladding for the system. The V value which characterizes the guidance properties of a fiber can be applied to this propagation. The control of the V value allows us to propagate single mode or multimode waveguides on a few centimeters. Numerical simulations of these waveguides based on a paraxial model including both photopolymerization and Kerr effect give very good agreement with our experimental results.