Negative refraction with little loss manipulated by the voltage and pulsed laser in double quantum dots

The paper demonstrates that negative refractive index can be achieved via tuning the tunneling rate between a double quantum dots(QDs) system by applying a bias voltage, and a pulsed laser. As the bias voltage being changed, the refraction index can be tunable to negative with the simultaneous negative permittivity and permeability. While the varying pulsed laser is applied to the double QDs system, moreover, the negative refractive index with little loss can be obtained. The flexible manipulation on a solid state system to realize negative refraction may give a new way for experimental research in the future.Comment: 10 pages, 6 figure

Two types of generalized integrable decompositions and new solitary-wave solutions for the modified Kadomtsev-Petviashvili equation with symbolic computation

The modified Kadomtsev-Petviashvili (mKP) equation is shown in this paper to be decomposable into the first two soliton equations of the 2N-coupled Chen-Lee-Liu and Kaup-Newell hierarchies by respectively nonlinearizing two sets of symmetry Lax pairs. In these two cases, the decomposed (1+1)-dimensional nonlinear systems both have a couple of different Lax representations, which means that there are two linear systems associated with the mKP equation under the same constraint between the potential and eigenfunctions. For each Lax representation of the decomposed (1+1)-dimensional nonlinear systems, the corresponding Darboux transformation is further constructed such that a series of explicit solutions of the mKP equation can be recursively generated with the assistance of symbolic computation. In illustration, four new families of solitary-wave solutions are presented and the relevant stability is analyzed.Comment: 23 page

Apical Sealing Ability of Bioceramic Paste and Mineral Trioxide Aggregate Retrofillings: A Dye Leakage Study

Introduction: This study compared the apical sealing ability of a bioceramic based root canalrepair filling material (iRoot FS) with mineral trioxide aggregate (MTA). Methods and materials: Forty single-canal teeth were prepared and randomly divided into two experimental groups (n=18) and two control groups (n=2). Teeth in experimental groups were retrofilled with either MTA or iRoot FS. After setting of the retrofillings, all roots were exposed to 0.2% Rhodamine B solution for 48 h and were then washed for 12 h before longitudinal sectioning. The extent of dye penetration was measured under fluorescence microscope. Results: The mean leakage values in MTA and iRoot FS samples were 35.63 and 35.15 µm, respectively. There was no significant differences between the two materials in this regard (P=0.584). Conclusion: According to dye leakage results, iRoot FS had similar apical sealing ability to MTA and might be considered as a promising root-end filling material