nanofibrous scaffolds produced by electrospinning have attracted much attention, recently. aligned and random nanofibrous scaffolds of poly (vinyl alcohol) (pva), poly (ε-caprolactone) (pcl) and nanohydroxyapatite  (nha) were fabricated by electrospinning method in this study. the composite nanofibrous scaffolds were subjected to detailed analysis. morphological investigations revealed that the...

nanofber  mats  of  poly(ε-caprolactone)/nanoclay  nanocomposites  were fabricated by electrospinning. the effects of the solution concentration and  the  nanoclay  content  of  nanocomposite  materials  on  the  fnal nanofber  structure were  investigated. morphology  and  diameter  of  the  nanofbers were studied using optical and scanning electron microscope. it was observed that the  poly(ε...

The enzymatic ring-opening copolymerization of ε-caprolactone (ε-CL) and β-lactam by using Candida antarctica lipase B (CAL-B) as catalyst was studied. Variation of the feed ratios of 25:75, 50:50, and 75:25 of ε-CL/β-lactam was performed. The products contain poly(ε-CL-co-β-lactam) and the homopolymers of poly(ε-CL) and poly(β-lactam). The structure of the copolymers was determined by MALDI-To...

Polymer-layered silicate nanocomposites belong to a new class of hybrid materials consisting of organic-synthetic polymer matrix and inorganic filler-layered structure clay minerals. The paper presents the results of FTIR, NMR, and SAXS studies of poly(ε-caprolactone)/sodium montmorillonite nanocomposites. We observed a correlation between the concentration of poly(ε-caprolactone) in nanocompos...

In this lecture, we will construct constant degree D vertex-expanders with expansion of (1 − ε)D (a.k.a. constant degree lossless expanders). This beautiful construction is due to Capalbo-ReingoldVadhan-Wigderson. Concretely, for every constant ε > 0 and every N , we will construct a bipartite graph (L,R,E), |L| = N , |R| = M = poly(ε)N), with left degree D = poly(1ε ), such that every subset S...

The crystallization behavior of poly(ε-caprolactone) (PCL) in a poly(vinylidene fluoride) (PVDF)/PCL blend as well as on a highly orientated PVDF substrate was studied by means of POM, DSC and TEM. The results show that the miscibility of the PVDF/PCL blend and the spherulitic morphology of PVDF varies with the blend ratio. For all the compositions, the pre-existing PVDF crystals accelerated th...

The copolymer based on Poly(3, 4-Ethylene dioxythiophen) and Poly(n-Vinylcarbazole) was characterized by FTIR Raman spectroscopy. temperature frequency evolutions of dielectric parameters are also plotted studied. dependence ε” the shows relaxation process for studied especially with frequencies about 1kHz temperatures: 90°C < T 118°C. values ε’ ∞ , ε’’ MAX time DC conductivity corresponding...

In this paper, we study the problem of L1-fitting a circle to a set of points in the plane, where the target function is the sum of distances of the points to the circle. We show an (1 + ε)-approximation algorithm, with running time O(n + poly(log n, 1/ε)), where poly(log n, 1/ε) is a constant degree polynomial in log n and 1/ε. This is the first subquadratic algorithm for this problem.