Orientation-dependent bending properties of selectively-filled photonic crystal fibres

A selective-filling technique was demonstrated to improve the optical properties of photonic crystal fibres (PCFs). Such a technique can be used to fill one or more fluid samples selectively into desired air holes. The technique is based on drilling a hole or carving a groove on the surface of a PCF to expose selected air holes to atmosphere by the use of a micromachining system comprising of a femtosecond infrared laser and a microscope. The exposed section was immersed into a fluid and the air holes are then filled through the well-known capillarity action [1, 2]. Provided two or more grooves are fabricated on different locations and different orientation along the fibre surface, different fluids may be filled into different air-holes to form a hybrid fibre. As an example, we filled half of a pure-silica PCF by a fluid with n=1.480 by carving a rectangular groove on the fibre (Figure 1). Consequently, the half-filled PCF became a bandgap-guiding structure (upper half), resulted from a higher refractive index in the fluid rods than in the fibre core [3], and three bandgaps were observed within the wavelength range from 600 to 1700 nm. Whereas, the lower half (unfilled holes) of the fibre remains an air/silica index-guiding structure (Figure 1(b)). When the hybrid PCF is bent, its bandgaps gradually narrowed, resulted from the shifts of the bandgap edges. The bandgap edges had distinct bend-sensitivities when the hybrid PCF was bent toward different directions. Especially, the bandgaps are hardly affected when the half-filled PCF was bent toward the fluid-filled region. Such unique bend properties could be used to monitor simultaneously the bend directions and the curvature of the engineering structures

Selectively fluid-filled microstructured optical fibers and applications

A versatile technique based on micromachining is demonstrated to fill selectively one or several different types of fluids into desired air holes in a microstructured optical fiber (MOF). Unique optical properties and applications of the selective-filled MOF are investigated

Existence Theorem for Periodic Solutions of Higher Order Nonlinear Differential Equations

AbstractWe study the existence of periodic solutions to differential equations of the formL(x)+g(t,x,x′,…,x(m))=f(t) withL(x)=x(m)+am−1x(m−1)+···+a1x′

Modelling and Analysis of a Pest-Control Pollution Model with Integrated Control Tactics

A hybrid impulsive pest control model with stage structure for pest and Holling II functional response is proposed and investigated, in which the effects of impulsive pesticide input in the environment and in the organism are considered. Sufficient conditions for global attractiveness of the pest-extinction periodic solution and permanence of the system are obtained, which show that there exists a globally asymptotically stable pest-extinction periodic solution when the number of natural enemies released is more than some critical value, whereas the system can be permanent when the number of natural enemies released is less than another critical value. Furthermore, numerical simulations are carried out to illustrate our theoretical results and facilitate their interpretation

Regional Differences in Entrepreneurial Intention of College Students May Exacerbate Regional Economic Gap

Entrepreneurial intention is the basis and premise to start entrepreneurial activities and entrepreneurial activities affect regional economic. Based on the survey, this study tries to carry out grey incidence clustering model analyzing data of entrepreneurial intention of 1431 college students. At the same time, 13 cities’ economy of these relevant universities adopt grey incidence clustering model. The results show that the both grey incidence cluster are consistent, which means the economic environment has an impact on the entrepreneurial intention of college students in this region. In turn, the different level of entrepreneurial intention resulting in different entrepreneurial activities further affects this regional economy if entrepreneurship education doesn\u27t work well. We draw a number of implications for the theory and practice of regional entrepreneurial economy development