Changes of physical properties of nylon 6 woven fabrics dyed with disperse dye were studied for crease recovery, bending resistance (JIS), surface roughness and sensory evaluation.
As for crease recovery, untreated fabric had the highest of all, followed by blank-dyeing (control), dyed fabrics. The decrease of fabric crease recovery by dyeing and blank-dyeing was due to a decrease in the tensile recovery of the yarn.
Bending resistance and the frictional coefficient increased and surface roughness was disordered in dyed and control fabrics.
This tendency of the dyed fabric was stronger than that of the control. It was thought that the increase of bending resistance was because of the fiber compacted in the fabric structure by shrinkage of the fabrics. This phenomenon corresponds to the disorder of the surface roughness and the increase in the frictional coefficient of dyed and control fabrics.
A fairly high correspondence with the above mentioned tendency was seen in the sensory evaluation. In addition, it was found that changes in the physical properties of nylon 6 fabrics by dyeing processing were perceiveable by human touch.

抄録全体を表示

Thermoluminescence (TL), differential scanning calorimeter (DSC) and stress-strain (S-S) curve were studied for polypropylene (PP) fibers irradiated with ultraviolet (UV) rays.
As for the samples which were irradiated with UV rays for 2 to 8 hours, a TL peak was observed at about 110°C. By contrast, UV irradiation over 10 hours gave rise to an appearance of luminescence peak at around 160°C, which could be ascribed to the suitable crystals.
It seemed that the two types of PP crystal play an important role as a trap of the excited electron and released some of trapped electrons emitting thermoluminescence in the temperature range of crystalline dispersion and melting. Two endothermic peaks on DSC were observed. The intensity of the lower peak decreased with an increase of UV irradiation time, being correlated with the TL behavior.
The breaking point on S-S curve was shifted to the lower strain side by this UV irradiation almost along the curve of the unirradiated fiber, and reached the yielding point after UV irradiation for 8 hours.
TL was thus proved to be one of the useful techniques for investigation of UV degradation on fibers.

抄録全体を表示

【目的】拡張型心筋症における心室性不整脈とT-wave alternans(TWA)の関連,ならびにTWAに影響を及ぼす因子につき検討した.【方法】拡張型心筋症51例を対象にCambridge Heart社製CH2000を用いて,安静時と運動時心電図からalternans解析を行った.Cohenらの基準に従い陽性,陰性,判定不能とし,心機能,遅延電位,QT dispersionおよび心室頻拍の有無につき陽性,陰性群で比較した.また,TWAに影響を及ぼす因子についてロジスティック回帰分析を用いて検討した.【結果】陽性20例,陰性22例,判定不能9例であった.陽性群において左室拡張末期径は有意に大,心室頻拍は高率に認められた.遅延電位,QT dispersionについては2群間に有意差を認めなかった.ロジスティック回帰分析では,TWAの独立決定因子は心室頻拍であった.【総括】拡張型心筋症において心室頻拍とTWAに密接な関連が認められ,心室頻拍の存在在はTWAの独立決定因子と考えられた.

抄録全体を表示

The change in physical properties of nylon 6 fiber dyed with a disperse dye was investigated using stress-strain curves, dynamic viscoelastic measurements, differential scanning calorimetry, and densiy measurements.
The initial rise and stress of the yield point, which follows the slope of initial rise of the stress-strain curve, were greater for the dyed fiber than they were for the control. At the same time, it was observed that in the case of dyed fiber, the shrinkage in fiber length which occurred during processing was suppressed more and the crystallinity increased more, compared to the control. The phenomena might be closely related to each other.
The tendency mentioned above was much clearer in the case of fiber treated with a higher drawing ratio. Although the amount of dye molecules absorbed into the fiber was almost the same for all dyed specimens, the induced changes in properties varied with the drawing ratio. Therefore, it could be assumed that induced changes in properties were not only due to the existence of the dye molecules in the fiber, but also to the structural change produced during the dyeing process.
When the dyed fiber was compared with the control, it was found that the temperature at which the storage modulus E' begins to drop shifted to the lower side, and a higher storage modulus existed in the rubbery elastic state. These results suggest that the dyeing treatment gives rise to a kind of structual separation in the amorphous region, that is, some amorphous regions consisting of loose packing molecules relax to a much looser packing state and some amorphous regions of close packing molecules result in a much closer, higher enthalpic packing state or crystallization. In other words, the dye molecule during the dyeing process, in cooperation with the thermal activation in the wet state, might play an important role in accelerating the moleculer movement of the polymer chain in the amorphous state and lead to structual separation as described above.

抄録全体を表示

The effects of dyeing on the physical property of polypropylene fibers have been studied.
From the results of stress-strain measurements, the dyed fibers generally show a lower initial slope compared to the blank dyed reference fiber. This trend is much clearer in the case of fiber specimens with a higher draw ratio. Dyeing causes a higher fiber shrinkage than the blank dyeing. Therefore, the lower initial slope of the dyed fibers may be due to the higher degree of shrinkage. The data further suggersts that the dye molecules accelerate the relaxation of molecular orientation in the amorphous region of fiber structure during the dyeing process.
As for the secondary yield stress and breaking strain, on the other hand, the dyed fiber shows a larger value than the reference respectively, regardless of the draw ratio. The a_c peak of dynamic loss modulus, E″ for dyed fiber shifts to a higher temperature. This probably means that the number of crystalline defects decrease during the dyeing procedure. Thus the increases of the secondary yield stress and the breaking strain for the dyed fiber can be interpreted as a result of dyeing process inducing more perfect crystalline state.
However, considering that those changes, mentioned above, take place with a very small dye take-up in fiber, it seems more reasonable to think that a lower initial slope, a higher secondary yield stress and higher breaking strain for the dyed fibers are not solely due to the existence of dye molecule in fiber structure, but also to the structural changes in the amorphous and crystalline regions which are induced during the dyeing process.

抄録全体を表示

冷却というペナルティーを越えるまでに技術が育ったとき,超伝導は急速に実用化に至る.ここ約10年,超伝導技術は生命科学,環境をはじめ,次世代の通信,交通運輸,電力システムに及ぶ広い分野に向けてポテンシャルを蓄え,あちこちで水面から顔を出そうとしている.これには,冷却技術の著しい進歩によるペナルティー・ラインの低下による寄与も大きい.本稿では,まず高温超伝導出現以来のここ約10年における超伝導関連技術の展開を概観し,次いで21世紀の社会環境の変化と超伝導技術のかかわりについて考察する.

抄録全体を表示