Cochannel Interference Cancelling Effects of MSE Processing and Viterbi Decoding in On-Board Processing Satellites

This paper presents cochannel interference cancelling techniques in on-board processing satellite systems using orthogonal polarizations. The techniques, based on mean square error (MSE) criterion and convolutional coding/soft decision Viterbi decoding (SDVD), are introduced on board. The bit error rate (BER) is derived for the mixed detection of a desired signal and an undesired cochannel interference when the techniques are applied to binary phase shift keying (BPSK), and is compared to that of no compensation for the interference. Performance results, obtained theoretically, show that the techniques of both the MSE and SDVD processings realize excellent improvements of the BER, and the improvements become significant in a large interference environment.     

SEM studies of electrolytic manganese dioxide

Manganese dioxide is deposited on the anode from MnSO₄ solution (95°C) containing H₂SO₄ and another acid, such as HCl and HNO₃. X-ray diffraction reveals a γ-MnO₂ structure. Addition of 0.1 M HCl or HNO₃ to the MnSO₄ solution containing H₂SO₄ results in lower cell voltage. Scanning electron micrographs of these surface deposits show that, in the case of a MnSO₄ + H₂SO₄ solution, a so-called fibrous microstructure was observed and crystal size became greater when the hydrochloric acid was added up to about 0.1 M.     

Improvement of the superconducting magnetic levitation system forthe determination of the magnetic flux quantum

An improvement of the preliminary superconducting magnetic levitation system for the absolute determination of the magnetic flux quantum is described. This improvement includes the development of the flux-up method to determine the flux in terms of the Josephson voltage. The improvement is essential for the determination of the magnetic flux quantum as well as of the coil current, in terms of the Josephson voltage and quantized Hall resistance     

Behavior of polymers containing spiroorthoester or bicycloorthoester structure under EB and X-ray irradiation conditions

Reaction behavior of spiroorthoester and bicycloorthoester to EB and X-ray irradiations has been studied on the basis of infrared spectroscopic analysis. The polymers containing these functional groups showed markedly high sensitivity to EB and X-ray. The formations of C?O and ? OH after exposure indicate that these functional groups react through ring opening even in the absence of any cationic catalyst. In the high energy-induced reaction, sensitivity and post-irradiation polymerization effect were found to be greatly influenced by the polymer structure, different from those observed in the cation-induced reaction.     

Photocationic and radical polymerizations by novel N‐phenacylammonium salts

Novel N‐phenacylammonium salts [N‐(α‐benzoylbenzyl)‐, N‐(1‐benzoylethyl)‐, N‐phenacyl‐, pyrazinium, 3‐bromoquinolinium, benzothiazolium, or p‐cyanopyridinium hexafluoroantimonates] were synthesized by the reaction of α‐benzoylbenzyl bromide, 2‐bromopropiophenone or phenacylbromide, and the corresponding N‐hetero aromatic compound, followed by anion exchange with KSbF₆. These N‐phenacylammonium salts showed higher activity than previously reported N‐benzyl‐2‐cyanopyridinium hexafluoroantimonate in the photopolymerization of epoxides. Further, these N‐phenacylammonium salts served as photoradical and thermal cationic initiators as well as photocationic initiators. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3470–3476, 2004     

Polymerization of methyl methacrylate with metal acetylacetonates and triethylaluminum catalysts

Polymerization of methyl methacrylate (MMA) with metal acetylacetonates, especially vanadium (III) acetylacetonate [V(acac)₃], in combination with AIEt₃ was studied. V(acac)₃–AIEt₃ catalyst could initiate the polymerization of MMA, although other Mt(acac)_xs are also effective. It was found that the polymerization of MMA with V(acac)₃–AIEt₃ catalyst proceeded through a coordination mechanism, from the results of copolymerization with styrene and polymerization in the presence of radical inhibitors. The resulting polymers were found to form stereocomplexes in acetone. Based on these results, it is concluded that multi-active sites in the polymerization of MMA with V(acac)₃–AIEt₃ catalyst were produced.     

Radical copolymerization of ethylene and 2-phenyl-3-vinyloxirane

The radical copolymerization of ethylene and 2-phenyl-3-vinyloxirane was carried out under high pressure to obtain the corresponding copolymers. The structure of the obtained copolymers was discussed by the data of infrared and nuclear magnetic resonance.     

Synthesis and isolation of molybdenum atomic wires

One of the main challenges in nanoscience and nanotechnology consists in the production and isolation of metallic atomic-scale nanowires (Benzryadin, C. N.; Lau, A.; Tinkham, M. Q. Nature 2000, 404, 971-974; Zach, M. P.; Ng, K. H.; Penner, R. M. Science 2000, 290, 2120-2123; Nilius, N.; Wallis, T. M.; Ho, W. Science 2002, 297, 1853-1856.). Here we report a unique and controllable way of isolating individual atomic molybdenum (Mo) chains by their encapsulation inside double-walled carbon nanotubes, exhibiting inner diameters ranging from 0.6 to 0.8 nm. We have found that these individual atomic chains form spontaneously within the hollow core of tubes in the absence of any reducing agent. We believe that these atomic-scale nanowires could now be studied without suffering oxidation, so that their physical and chemical properties are elucidated.     

Carbon nanotubes with high bone-tissue compatibility and bone-formation acceleration effects

Carbon nanotubes (CNTs) have been used in various fields as composites with other substances or alone to develop highly functional materials. CNTs hold great interest with respect to biomaterials, particularly those to be positioned in contact with bone such as prostheses for arthroplasty, plates or screws for fracture fixation, drug delivery systems, and scaffolding for bone regeneration. Accordingly, bone-tissue compatibility of CNTs and CNT influence on bone formation are important issues, but the effects of CNTs on bone have not been delineated. Here, it is found that multi-walled CNTs adjoining bone induce little local inflammatory reaction, show high bone-tissue compatibility, permit bone repair, become integrated into new bone, and accelerate bone formation stimulated by recombinant human bone morphogenetic protein-2 (rhBMP-2). This study provides an initial investigational basis for CNTs in biomaterials that are used adjacent to bone, including uses to promote bone regeneration. These findings should encourage development of clinical treatment modalities involving CNTs.