Dalitz plot analysis of the decay D(+)-->K(-)pi(+)pi(+) and indication of a low-mass scalar Kpi resonance

We study the Dalitz plot of the decay D(+)-->K(-)pi(+)pi(+) with a sample of 15090 events from Fermilab experiment E791. Modeling the decay amplitude as the coherent sum of known Kpi resonances and a uniform nonresonant term, we do not obtain an acceptable fit. If we allow the mass and width of the K(*)(0)(1430) to float, we obtain values consistent with those from PDG but the chi(2) per degree of freedom of the fit is still unsatisfactory. A good fit is found when we allow for the presence of an additional scalar resonance, with mass 797+/-19+/-43 MeV/c(2) and width 410+/-43+/-87 MeV/c(2). The mass and width of the K(*)(0)(1430) become 1459+/-7+/-5 MeV/c(2) and 175+/-12+/-12 MeV/c(2), respectively. Our results provide new information on the scalar sector in hadron spectroscopy.     

Thermal Stability Evaluation of PA6/LLDPE/SEBS-g-DEM Blends

Summary: The thermal stability of a polyamide-6/low linear density polyethylene blend (PA6/LLDPE) was studied using thermal analysis techniques. The thermogravimetric studies carried out showed that when a diethyl maleate grafted styrene- ethylene/butadiene-styrene terpolymer (SEBS-g-DEM) is added to the PA6/LLDPE blend there is an actual enhancement of the thermal stability due to the increase in the interfacial area within the blend. The Invariant Kinetic Parameter method (IKP) proved to be a qualitative technique unfolding the type of degradation mechanisms taking place in the material vicinity. Nucleation and phase boundary reactions are the kinetic models of thermal decomposition with the most significant probability of occurring.     

Refractive index measurements of solid parahydrogen

Solid para-H2 is a promising gain medium for stimulated Raman scattering, due to its high number density and narrow Raman linewidth. In preparation for the design of a cw solid hydrogen Raman laser, we have made the first measurements, to our knowledge, of the index of refraction of a solid para-H2 crystal, in the wavelength range of 430-1100?nm. For a crystal stabilized at 4.4?K, this refractive index is measured to be n(p-H2)=1.130±0.001 at 514?nm. A slight, but significant, dependence on the final crystal-growth temperature is observed, with higher n(p-H2) at higher crystal-growth temperatures. Once a crystal is grown, it can be heated up to 10?K with no change in n(p-H2). The refractive index varies only slightly over the observed wavelength range, and no significant birefringence was observed.     

Preparation and characterization of 1-ethyl-3-methylimidazolium chloride–based gel polymer electrolyte in electrochemical double-layer capacitors

Journal of Solid State Electrochemistry - Electrochemical double-layer capacitors (EDLCs) have recently received an enormous attraction due to their ability to produce higher power density without...     

Parallel asynchronous focal plane array processing

A new approach to focal plane processing based on silicon injection mode devices is suggested. These devices provide a natural basis for parallel asynchronous focal plane image preprocessing. The simplicity and novel properties of the devices would permit an independent analog processing channel to be dedicated to every pixel. A laminar architecture built from arrays of the devices would form a two-dimensional (2-D) array processor with a 2-D array of inputs located directly behind the focal plane detector array. A 2-D image data stream would propagate in neuronlike asynchronous pulse coded form through the laminar processor. No multiplexing, digitization or serial processing would occur in the preprocessing stage. High performance is expected because approximately linear pulse coding has already been observed for input currents ranging over six orders of magnitude down to one picoampere with noise referred to input of about 10 femtoamperes. Very low power requirements suggest utility in space and in conjunction with very large arrays. Multispectral processing is possible because of compatibility with the cryogenic environment of high performance infrared detectors.     

Boronate affinity saccharide electrophoresis: a novel carbohydrate analysis tool

The incorporation of specialised carbohydrate affinity ligand methacrylamido phenylboronic acid in polyacrylamide gels for fluorophore-assisted carbohydrate electrophoresis greatly improved the effective separation of saccharides that show similar mobilities in standard electrophoresis. Polyacrylamide gel electrophoresis using methacrylamido phenylboronic acid in low loading (typically 0.5-1% dry weight) was unequivocally shown to alter retention of labelled saccharides depending on their boronate affinity. While conventional fluorophore-assisted carbohydrate electrophoresis of 2-aminoacridone labelled glucose oligomers showed an inverted parabolic migration, an undesired trait of small oligosaccharides labelled with this neutral fluorophore, boron affinity saccharide electrophoresis separation of these carbohydrates completely restored their predicted running order, based on their charge/mass ratio, and resulted in improved separation of the analyte saccharides. These results exemplify boron affinity saccharide electrophoresis as an important new technique for analysing carbohydrates and sugar-containing molecules.     

Highly Flexible Dielectric Films from Solution Processable Covalent Organic Frameworks**

Covalent organic frameworks (COFs) are known to be a promising class of materials for a wide range of applications, yet their poor solution processability limits their utility in many areas. Here we report a pore engineering method using hydrophilic side chains to improve the processability of hydrazone and β-ketoenamine-linked COFs and the production of flexible, crystalline films. Mechanical measurements of the free-standing COF films of COF-PEO-3 (hydrazone-linked) and TFP-PEO-3 (β-ketoenamine-linked), revealed a Young's modulus of 391.7 MPa and 1034.7 MPa, respectively. The solubility and excellent mechanical properties enabled the use of these COFs in dielectric devices. Specifically, the TFP-PEO-3 film-based dielectric capacitors display simultaneously high dielectric constant and breakdown strength, resulting in a discharged energy density of 11.22 J cm⁻³. This work offers a general approach for producing solution processable COFs and mechanically flexible COF-based films, which hold great potential for use in energy storage and flexible electronics applications.