The computer program based on our mathematical model of the plain knitting process can predicted the loop length and the course length, the yarn tensions in the plain knitting zone, the robbing back length on the course, the robbing back rate, the maximum yarn tension value and position. The effects of the frictional coefficient of yarn/knitting elements on the course length, the yarn tensions in the plain knitting zone, the robbing back length on the course, the robbing back rate, the maximum yarn tension value and position are analyzed theoretical. The results obtained are as follows. 1) The course length increases with the increase of the frictional coefficient. 2) The robbing back length and the robbing back rate decrease with the increase of the frictional coefficient. 3) The maximum tension value increases with the increase of the frictional coefficient.

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The structural development of poly(p-phenylene sulfide) (PPS) fibers was analyzed through in-situ wide angle X-ray diffraction and small angle X-ray scattering during CO₂ laser heated drawing. The in-situ measurements were carried out as a function of elapsed time after necking, achieving a high time resolution of 0.25 ms. The quasi-hexagonal phase appeared just after neck-drawing, and developed with increasing crystal orientation factor and decreasing long period and d-spacing within less than 1 ms after drawing. The crystallization induction time and the crystallization rate of the quasi-hexagonal phase obtained from the equatorial intensity profiles were 0.02 ms and 3.0 ms^-1. The crystal orientation factor continued to increase, and saturated about 0.95 at about 8 ms after necking. And after then, the quasi-hexagonal phase started to transform into orthorhombic crystal in several decades of milliseconds with the decreasing of fiber temperature.

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A diluted micro-fibrillated cellulose (MFC) dispersion with cationic polyacrylamide (C-PAM) aq. solution was casted and dried as a plausible model material of fiber-to-fiber bonds in paper containing C-PAM. Mechanical and dynamic mechanical properties of the MFC/C-PAM mixture sheets (MFC/C-PAM sheets) obtained were studied, comparing with those of papers containing C-PAM. The high density and Young's modulus of the MFC/C-PAM sheet, which was twice those of the paper without C-PAM, suggested higher consolidation and fully developed fibril-fibril bonds due to the quite small dimensions of MFC. A significant decrease in scattering coefficient of the MFC/C-PAM sheets accompanied by an increase of C-PAM content suggested that almost all of the C-PAM in the MFC/C-PAM sheets could locate surrounding fibril-fibril bonds. Tensile strength of MFC/C-PAM sheet was far larger than that of the paper without C-PAM. However, the strength increment of the MFC/C-PAM sheets with increasing C-PAM content was smaller than that expected from the difference of Young's modulus between MFC/C-PAM sheets and the papers containing C-PAM, partly because C-PAM itself is brittle. The dynamic mechanical properties of the MFC/C-PAM sheets were, on the whole, similar to those of the paper containing C-PAM, suggesting that the role of C-PAM on the mechanical property (or bonding) was minimal and the most of it was derived from fibril-fibril (hydrogen) bonding in the MFC/C-PAM sheets. Measurement of (dynamic) mechanical properties of the sheets consisted of MFC and various water soluble polymers could be used to evaluate the effects of the polymers on mechanical properties of papers when the polymers were used as dry strength agents.

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