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Volume 53, Issue 12
Displaying 1-12 of 12 articles from this issue
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Takaaki Ishigure, Eisuke Nihei, Yasuhiro Koike1997 Volume 53 Issue 12 Pages 520-525
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSThis paper describes the high speed transmission characteristics of the perdeuterated poly methyl methacrylate (PMMA-d8) base graded-index (GI) polymer optical fiber (POF). The PMMA-d8 base GI POF was obtained by the interfacial-gel polymerization technique. We succeeded in I Gb/s 160m transmission at 650-nm wavelength in the 160-m GI POF link. In general, the possible transmission distance of the PMMA POF link is limited to approximately 100m because of high attenuation. However, substitution of hydrogen atoms in the polymer for deuterium atoms decreases the intrinsic absorption loss. The total attenuation of the PMMA-d8 base GI POF at 650-nm wavelength was about 60dB/km which is approximately half of the attenuation of PMMA base GI POF. Therefore the low-loss PMMA-d8 base GI POF enables longer distance communication. We also analyzed the dispersion property of the PMMA-d8 base GI POF by utilizing WKB method in which both modal and material dispersion were taken into consideration. It was clarified that approximately 2Gb/s transmission can be achieved by the PMMA-d8 base GI POF with 200-m length when 650-nm wavelength is adopted as the signal wavelength. The PMMA-d8 base fiber has two optical windows of light transmission which are located around 650-680-nm and 780-nm wavelengths. As the material dispersion decreases with increasing the signal wavelength, the use of the light source operating at 780nm is effective for higher bit rate transmission. It was also confirmed that the PMMA-d8 base GI POF can transmit about 3Gb/s for 200m when the signal wavelength is 780nm. These experimental and theoretical results indicate that the PMMA-d8 base GI POF could be one of the promising candidate of the physical layers in the high speed multimedia network.View full abstractDownload PDF (1037K) -
Zheng Song, Kenji Hisada, Isao Tabata, Teruo Hori1997 Volume 53 Issue 12 Pages 526-532
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSAcetylcelluloses with different degrees of acetyl substitution (DS) were prepared by removing a part of the acetyl substituents from a commercial cellulose acetate in acidic conditions. First, the solubility of the prepared acetylcellulose was investigated in some organic solvents and their aqueous mixtures. The acetylcellulose samples with different DS were then treated in a buffer solution of pH 4.5 containing a commercial cellulase (from Trichoderma viride) for given times. Both the supernatant solution and/or the residue which existed as precipitates after the cellulase treatment were analyzed by means of viscosity measurements, high performance liquid chromatography, gel permeation chromatography, glucose detection and so on.
With the acetylcellulose having higher DS (>2.20), no direct evidence that it had been degraded by the cellulase were obtained. On the other hand, with the acetylcelluloses covering DS range from 0.58 to 2.19, the cleavage of the polymer chains occured to the extent depending on the DS. For DS=0.58_??_1.08, free glucose molecules were detected and its amount decreased clearly with increasing DS.
In conclusion, it was proved that cellulase undergoes the degradation of acetylcellulose, that had never been reported.View full abstractDownload PDF (596K) -
Kwan-Jun Jeon, Kaname Katsuraya, Yutaro Kaneko, Toru Mimura, Toshiyuki ...1997 Volume 53 Issue 12 Pages 533-539
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSTo elucidate the action mechanism of bioactive sulfated polysaccharides which exhibited anticoagulant and antiviral activities, interactions of an anticoagulant polysaccharide heparin (Hep) with polylysine (PL) which can be regarded as a model compound for an anticoagulant protein antithrombin-III, respectively, were examined by NMR spectroscopy. It was found that a gellike complex was formed by the ionic interaction of Hep with PL. Since in 1H NMR spectra of the mixture of Hep and PL, absorptions due to the lysine side chain appeared as two species which were due to excess free polylysine and gellike complex, the proportion of the complex was determined. The proportion of the gellike complex was affected by _??_w of heparin and polylysine, molar ratio, pH, concentration, temperature, and time. Maximal amount of the gellike complex was attained with Hep having 3×103 Da and PL having 10×103 Da.View full abstractDownload PDF (489K) -
Hyungjoong Jeon, Hiroshi Ito, Takeshi Kikutani, Norimasa Okui1997 Volume 53 Issue 12 Pages 540-548
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSHigh-speed melt spinning of poly (ethylene terephthalate) was performed using a nozzle with extraordinary large diameter of 5mm. A metallic porous filter was set in the nozzle to maintain high extrusion pressure. The structure of the as-spun fibers was compared with the fibers prepared using an ordinary nozzle. The molecular orientation of fibers spun at low take-up velocities, where orientation-induced crystallization did not take place, increrased by enlarging the nozzle diameter. The orientation-induced crystallization started at lower take-up velocities because of enhanced molecular orientation. On the other hand, the structure of crystallized fibers obtained at high take-up velocities was characterized by high crystallinity and relatively low molecular orientation. The on-line measurement of spinline velocity for the take-up velocity of 5km/min revealed that, in comparison with the spinning with ordinary nozzle, the spinline velocity increased more steeply near the spinneret and the solidification of the spinline occurred at a position closer to the spinneret. The solidification temperature, i. e. the crystallization temperature, estimated from the measured velocity profile also increased by enlarging the nozzle diameter. These changes were attributed to increase in temperature difference between center and surface of the spinline, which might lead to the stress concentration and the promotion of orientation-induced crystallization in the skin layer.View full abstractDownload PDF (1161K) -
F. Katzenberg, H. Liebertz, J. Petermann1997 Volume 53 Issue 12 Pages 549-554
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSThis paper reports the possibility to produce highly uniaxially oriented thin films of thermoplastic polymers by friction transfer onto smooth, rigid substrates. The resulting degree of orientation and thickness of these films depends on parameters such as sliding rate, pressure and substrate temperature. Moreover, an uniaxial orientation in the friction contact area of the sliding polymer bar takes place, too. This gives the possibility, to uniaxially orient nanometer thin layers on the surface of non-oriented polymer bulk material.View full abstractDownload PDF (2469K) -
Christopher J., G. Plummer, Hans-Henning Kausch1997 Volume 53 Issue 12 Pages 555-564
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSOriented films of PTFE, UHMWPE and Vectra, TM prepared by friction transfer, have been investigated using transmission electron microscopy (TEM) and atomic force microscopy (AFM), and the results have been compared. These techniques can provide molecular resolution of the internal structure and the sample surface respectively, with certain limitations. Molecular imaging with AFM has the advantage of not being limited to crystallographic planes showing strong Bragg reflections and belonging to zones whose axis is parallel to the observation direction. On the other hand, high-resolution AFM images generally correspond to very restricted sample areas (typically≤200nm2), so that large numbers of images may be necessary to obtain a reasonable representation of a heterogeneous sample surface.View full abstractDownload PDF (7954K) -
Takashi Itoh, Masato Hashimoto1997 Volume 53 Issue 12 Pages 565-569
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSPoly (p-phenylene terephthalamide) fibers (Kevlar 29 and 49) were thin-sectioned or treated with a mixed solvent of sulfuric-acid/water (SAW) to be observed in transmission and/or scanning electron microscopes. Microfibrillar and pleated-band morphology existed in Kevlar 29 and 49 fibers, while the skin-core structure was confirmed only in Kevlar 29 fiber. A microfibril ca. 100nm thick is composed of several tens of needle-shaped microcrystals 10_??_20nm thick, being pleated with a period of 500_??_600nm along the fiber axis. Hydrogen-bonding or crystal structure in the core region was considered to be more ordered than that in the skin region in the case of Kevlar 29 fiber. Orientation of microcrystals in each microfibril was incoherent although b-axis orientation mainly distributed around the radial direction. Such tendency is more prominent for Kevlar 29 fiber which was finally suggested to assume the hierarchical morphology of “pleated-microcrystal band”.View full abstractDownload PDF (3625K) -
YUJI MATSUMOTO1997 Volume 53 Issue 12 Pages P402-P406
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSDownload PDF (1814K) -
TAKAYUKI OKAYAMA1997 Volume 53 Issue 12 Pages P407-P411
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSDownload PDF (1221K) -
JUNTA EGAWA1997 Volume 53 Issue 12 Pages P412-P415
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSDownload PDF (779K) -
SHOGO KACHI, TETSUO AOYAGI1997 Volume 53 Issue 12 Pages P416-P420
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSDownload PDF (927K) -
TAKEYUKI MATSUO1997 Volume 53 Issue 12 Pages P425-P426
Published: December 10, 1997
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSDownload PDF (1224K)
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