Summary: A method to measure the Young's modulus of a single electrospun polyacrylonitrile (PAN) fiber is reported. The Young's modulus can be calculated from the force‐displacement curves obtained by the bending of a single fiber attached to an atomic force microscopy (AFM) cantilever. It is suggested that the high modulus of electrospun fibers is caused by the orientation of molecular chains, which is confirmed by wide‐angle X‐ray diffraction (WAXD) measurements. The communication will provide a basic understanding of the relationship between mechanical properties and structures of electrospun fibers.
A PAN fiber was attached to a contact mode cantilever to facilitate the measurement of force‐displacement curves and Young's modulus. 相似文献
The paper proposes a model for a cold rolling mill process in the full-film regime that uses lubricant emulsion sprayed on
at the entrance of the strip. The aim of the model is to forecast the reduction of strip thickness versus the flow rate of
lubricant given the other operation parameters. The model includes strip plastic deformation, lubricant flow and lubricant
viscosity depending on pressure. The mathematical problem is a free boundary one and a numerical procedure, applied to an
industrial plant, is presented with some results. 相似文献
This article proves a characterisation of the classical unital that is a generalisation of a characterisation proved in 1982
by Lefèvre-Percsy. It is shown that if is a Buekenhout-Metz unital with respect to a line in such that a line of not through meets in a Baer subline, then is classical. An immediate corollary is that if is a unital in PG such that is Buekenhout-Metz with respect to two distinct lines, then is classical.
Received 5 August 1999; revised 15 February 2000. 相似文献
Many problems in chemistry, physics and engineering requires the inversion of a Fredholm integral equation of first order. To find the solution of this problem one has to deal with ill-posed problem and special techniques have to be used. In this paper two of the most common methods, the Tikhonov regularization and the singular value decomposition, are compared when finding the solution of a model integral equation. The regularization parameter in the Tikhonov regularization and the dimension of the subspaces in the singular value decomposition were chosen using the L curve criterion. The analytical solution of the model integral equation was taken as a reference to analyze the results. The advantages of each method, with the presence of errors in the data, is presented and it is argumented the superiority of the singular value decomposition when dealing with this kind of problem. 相似文献
LetX be an integral projective curve andL ∃ Pica(X),M ∃ Picb (X) with h1(X, L)= h1(X, M) = 0 andL, M general. Here we study the rank of the multiplication map μL,M:H0(X,L)⊗H0(X,M)→H0(X,L⊗M). We also study the same problem whenL andM are rank 1 torsion free sheaves onX. Most of our results are forX with only nodes as singularities. 相似文献