Effect of the composition on the phase size in immiscible blends with the viscosity ratio close to unity

The influence of the composition and interfacial tension on the phase size in immiscible polymer blends with a viscosity ratio close to unity has been investigated with poly(methyl methacrylate)/poly(ethylene terephthalate) blends and data from various works. For all the blends considered, the dispersed particle diameter (d) is proportional to the interfacial tension of the system. When the dispersed‐phase content (?) is below 1%, there is minimal change of d with increasing ?. When ? is between 1 and 20%, d is proportional to ?^0.4. It seems that the processing conditions do not influence the morphology significantly for blend systems with a viscosity ratio close to unity.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1791–1799, 2003     

A new characterization of sub-μm parallel multilevelinterconnects and experimental verification

This paper describes the generation of a new universal design chart for submicron multilevel interconnection and its verification using test-structures. This has been developed to give the precise interconnect-capacitance for parallel submicron multilevel interconnections. Parasitic effects of a passivation film (Si₃N₄) on the interconnect capacitance have been also studied. The results of the test-structures designed have shown an excellent agreement with the design-chart with a maximum error of 8%. Furthermore, a simple propagation delay and response voltage model to a step voltage input have been developed incorporating the parallel-interconnect capacitance model. The new model is based on a lossy-transmission line equation and demonstrates an excellent agreement with RC lumped circuit simulations, resulting in a new simple and accurate prediction method for interconnect delay for use in VLSI timing design     

Determination of organotin compounds in polyvinyl chloride toys

Organotin compounds in polyvinyl chloride toys were determined by GC/MS after ethyl derivatization with sodium tetraethylborate. The samples were 12 balls, 12 soft toys, 10 food toys and 13 face masks for children. Monooctyltin, dioctyltin and trioctyltin compounds were found in all face masks at the levels of 74.8-917 micrograms/g. 474-3,960 micrograms/g and 1.0-213 micrograms/g, respectively. They also were detected in 6 balls, 4 soft toys and 1 food toy. Monomethyltin and dimethyltin compounds were found in 8 face masks at the levels of 40.9-227 micrograms/g and 222-1,450 micrograms/g, respectively. Monobutyltin and dibutyltin (DBT) compounds were found in 1 ball, 3 food toys and 5 face masks. In particular, 1 ball and 4 face masks contained toxic DBT at the levels of 527-999 micrograms/g.     

The action modes of an extracellular beta-1,3-glucanase isolated from Bacillus clausii NM-1 on beta-1,3-glucooligosaccharides

The mode of action of an extracellular -1,3-glucanase from Bacillus clausii NM-1 on beta-1,3-3glucooligosaccharides and their alditols was studied. The enzyme could not hydrolyze laminaribiose or laminaritriose. beta-1,3-Glucooligosaccharides higher than laminarihexaose were rapidly hydrolyzed, while laminaritetraose was slowly hydrolyzed. The k(cat)/K(m) ratios for a series of beta-1,3-glucooligosaccharides from laminaritetraose to laminariheptaose showed that the substrate binding site of the enzyme covered a wide range of beta-1,3-glucooligosaccharides having six glucose residues. The action pattern of the enzyme on the alditols corresponding to each laminarioligosaccharide suggested that the catalytic site of the enzyme existed between the third and fourth glucose residue from the non-reducing terminal. The value of k(cat)/K(m) also suggested that the sixth binding position contributed to the catalytic efficiency and stability.     

OTDR in optical transmission systems using Er-doped fiber amplifiers containing optical circulators

Fault location in optical amplifier transmission systems is described. Optical time-domain reflectometry (OTDR) cannot be used for an optical transmission line containing traditional Er-doped fiber amplifiers (EDFAs) because they contain optical isolators. The authors propose an OTDR scheme that uses new EDFAs containing optical circulators and return transmission lines. The new EDFAs support both OTDR and digital signal transmission. A 280.9 km transmission line containing three of the proposed EDFAs was constructed and tested. Experimental results demonstrated the feasibility of OTDR fault location and 1.8-Gb/s digital signal transmission.<>     

Design and Performance of WDM Transmission Systems at 6.3 Mbits/s

One- and two-way 6.3 Mbit/s optical transmission systems employing wavelength-division-multiplexing (WDM) are designed for application to telephone networks. Multiplexing at two wavelengths, 1200 and 1300 nm, as well as that at 810 and 890 nm, is found to be effective after taking the application fields and present fabrication techniques for optical multiplexers into account. Requirements for optical multiplexers are clarified through SNR design in which crosstalk is dealt with effectively. Optical multiplexers composed of newly developed dielectric multilayer thin-film filters are designed to meet the systems' requirements, and good transmission quality is confirmed for the systems by experiments.     

Experimental study on the concentration process of trace element through a food chain from the viewpoint of nutrition ecology

This paper describes the importance of a food chain to estimate the concentration of heavy metals from the viewpoint of nutrition ecology.The experiments were performed to investigate the effects of the following experimental conditions on the uptake of heavy metals by a predator, using ¹³⁷Cs as a tracer; ration size per day, feeding interval and the change in weight of the predator fish. Top minnows (Oryzias latipes) were used as preys and Golden astro (Astronotus ocellatus) as predators. The preys were raised without feeding in an aquarium and the predators were fed top minnows.The set of results showed that (1) the concentration of a metal in predator fish increased with the ration size, (2) the feeding interval had no effect on the uptake of the metal by fish under the experimental conditions performed, and (3) the concentration in the growing fish was suppressed increasing in value with the increase of its weight. They suggest the importance of generalization of the experimental food conditions when the study on the concentration process of heavy metals through a food chain is performed. The paper also deals with the compartment model applied to the concentration process of the metal by a fish. The theoretical results depicted well the experimental ones.     

Low-loss 4 × 4 optical matrix switch for fibre-optic communication

A low-loss and high-repeatability 4 × 4 optical matrix switch fabricated by using rhombic glass-block switch elements is described. The maximum loss was 1.3 dB and the crosstalk was less than ?55 dB, with a switching delay of less than 18 ms.     

Gallium-67 scanning in the differentiation of maxillary sinus carcinoma from chronic maxillary sinusitis

Gallium-67 scans of 25 patients in whom the clinical symptoms and radiographic findings were suggestive of either maxillary sinus carcinoma or chronic sinusitis proved to be valuable in the differentiation between the two disease processes. Those patients with carcinoma had positive scans, while those with sinusitis had either negative or only weakly positive scans.