On the Growth and Fixed Points of Solutions of Second Order Differential Equations with Meromorphic Coefficients

In this paper, we investigate the growth and fixed points of solutions and their 1st, 2nd derivatives, differential polynomial of second order linear differential equations with meromorphic coefficients, and obtain that the exponents of convergence of these fixed points are all equal to the order of growth.     

Vector Variational Inequalities for Nondifferentiable Convex Vector Optimization Problems

In this paper, we consider a nondifferentiable convex vector optimization problem (VP), and formulate several kinds of vector variational inequalities with subdifferentials. Here we examine relations among solution sets of such vector variational inequalities and (VP). Mathematics Subject classification (2000). 90C25, 90C29, 65K10 This work was supported by the Brain Korea 21Project in 2003. The authors wish to express their appreciation to the anonymous referee for giving valuable comments.     

Local duality theorem for q-ary 1-perfect codes

In this paper, we derive the relationship between local weight enumerator of q-ary 1-perfect code in a face and that in the orthogonal face. As an application of our result, we compute the local weight enumerators of a shortened, doubly-shortened, and triply-shortened q-ary 1-perfect code.     

On subnormal solutions of second order linear periodic differential equations

In this paper, we investigate the existence and the form of subnormal solution for a class of second order periodic linear differential equations, estimate the growth properties of all solutions, and answer the question raised by Gundersen and Steinbart.     

Transparent p‐NiO/n‐ZnO diodes used in circuit rectifiers

We report on the fabrication of a transparent photostable cell circuit composed of drive and resistor diodes which are face‐to‐face connected to each other with different device area. The diodes consisted of e‐beam evaporated p‐NiO on sputter‐deposited n‐ZnO for p/n diode formation on indium‐tin‐oxide glass. Our transparent diodes show photostable rectifying behavior, about 10³ on/off current ratio and even dynamic rectification at a maximum frequency of 100 Hz AC input signal in ambient light. The noticeable photo‐responsivity of the circuit was obtained only under ultraviolet (UV) light. We conclude that our transparent diode circuit is promising in enriching the field of transparent device electronics. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Long optically controlled delays in optical fibers

Optically controlled delay lines in optical fibers are demonstrated by use of the group-velocity control of signal pulses based on stimulated Brillouin scattering. We achieve continuous time delay within the range of 150 ns, much larger than the width of the 40 ns signal pulse, using cascaded fiber segments joined by unidirectional optical attenuators. In the meantime, we also observe a large amount of pulse broadening, which agrees well with a theoretical prediction based on linear theory.     

Integrated electro-optic platform using ferroelectric crystals with the point symmetry of orthorhombic mm2

We theoretically and numerically investigate the modulation efficiencies of integrated electro-optic (EO) modulators based on ferroelectric crystals with the point symmetry of orthorhombic mm2. An analytical expression describing the index-ellipsoid under the EO effect is derived, where all 5 non-zero linear EO coefficients of mm2-crystals are considered. As practical candidates for integrated EO platform, three mm2-crystals (KNbO₃, KTiOPO₄, and Ba₂NaNb₅O₁₅) that are well-established and commercially available are chosen for numerical simulations. The refractive-index (RI) changes caused by an external electric field applied to each crystal with an arbitrary direction are analyzed in detail for the given optical polarization states of input light wave. For each crystal, the modulation efficiency is evaluated in terms of the half-wave voltage required for a π-phase shift of input wave, which is compared with the established counterpart based on LiNbO₃. The results indicate that higher modulation efficiencies are achievable in the two schemes using KNbO₃ and Ba₂NaNb₅O₁₅ than those for other cases, meaning that either lower power-consuming or larger beam-window integrated EO devices are feasible.