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This paper presents high quality YBa2Cu3O7-δ (YBCO) thin films on LaAlO3 substrate for microwave devices prepared by Pulsed Laser Deposition (PLD). The double-sided YBCO films cover a large area and have been optimized for key parameters relevant to microwave device applications, such as surface morphology and surface resistance (R s). This was achieved by improving target quality and increasing oxygen pressure during deposition, respectively. To evaluate the suitability of the YBCO films for microwave devices, a pair of microwave filters based on microstrip fabricated on films from this work and a commercial company were compared. The results show that the YBCO films in this work could completely meet the requirements for microwave devices.

Solving nonlinear partial differential equations have attracted intensive attention in the past few decades. In this paper, the Darboux transformation method is used to derive several positon and hybrid solutions for the (2+1)-dimensional complex modified Korteweg–de Vries equations. Based on the zero seed solution, the positon solution and the hybrid solutions of positon and soliton are constructed. The composition of positons is studied, showing that multi-positons of (2+1)-dimensional equations are decomposed into multi-solitons as well as the (1+1)-dimensions. Moreover, the interactions between positon and soliton are analyzed. In addition, the hybrid solutions of b-positon and breather are obtained using the plane wave seed solution, and their evolutions with time are discussed.

We give the bilinear form and n-soliton solutions of a (2+1)-dimensional [(2+1)-D] extended shallow water wave (eSWW) equation associated with two functions v and r by using Hirota bilinear method. We provide solitons, breathers, and hybrid solutions of them. Four cases of a crucial ϕ ( y ) , which is an arbitrary real continuous function appeared in f of bilinear form, are selected by using Jacobi elliptic functions, which yield a periodic solution and three kinds of doubly localized dormion-type solution. The first order Jacobi-type solution travels parallelly along the x axis with the velocity ( 3 k 1 2 + α , 0 ) on (x, y)-plane. If ϕ ( y ) = sn ( y , 3 / 10 ) , it is a periodic solution. If ϕ ( y ) = cn ( y , 1 ) , it is a dormion-type-I solutions which has a maximum ( 3 / 4 ) k 1 p 1 and a minimum − ( 3 / 4 ) k 1 p 1 . The width of the contour line is ln [ ( 2 + 6 + 2 + 3 ) / ( 2 + 6 − 2 − 3 ) ] . If ϕ ( y ) = sn ( y , 1 ) , we get a dormion-type-II solution (26) which has only one extreme value − ( 3 / 2 ) k 1 p 1 . The width of the contour line is ln [ ( 2 + 1 ) / ( 2 − 1 ) ] . If ϕ ( y ) = sn ( y , 1 / 2 ) / ( 1 + y 2 ) , we get a dormion-type-III solution (21) which shows very strong doubly localized feature on (x,y) plane. Moreover, several interesting patterns of the mixture of periodic and localized solutions are also given in graphic way.

We report combined magnetic susceptibility, dielectric constant, nuclear quadruple resonance (NQR) and zero-field nuclear magnetic resonance (NMR) measurements on single crystals of multiferroics CuBr$_2$. High quality of the sample is demonstrated by the sharp magnetic and magnetic-driven ferroelectric transition at $T_N=T_C\approx$ 74~K. The zero-field $^{79}$Br and $^{81}$Br NMR are resolved below $T_N$. The spin-lattice relaxation rates reveal charge fluctuations when cooled below 60~K. Evidences of an increase of NMR linewidth, a reduction of dielectric constant, and an increase of magnetic susceptibility are also seen at low temperatures. These data suggest an emergent instability which competes with the spiral magnetic ordering and the ferroelectricity. Candidate mechanisms are discussed based on the quasi-one-dimensional (1D) nature of the magnetic system.

Formation control and obstacle avoidance for multi-agent systems have attracted more and more attention. In this paper, the problems of formation control and obstacle avoidance are investigated by means of a consensus algorithm. A novel distributed control model is proposed for the multi-agent system to form the anticipated formation as well as achieve obstacle avoidance. Based on the consensus algorithm, a distributed control function consisting of three terms (formation control term, velocity matching term, and obstacle avoidance term) is presented. By establishing a novel formation control matrix, a formation control term is constructed such that the agents can converge to consensus and reach the anticipated formation. A new obstacle avoidance function is developed by using the modified potential field approach to make sure that obstacle avoidance can be achieved whether the obstacle is in a dynamic state or a stationary state. A velocity matching term is also put forward to guarantee that the velocities of all agents converge to the same value. Furthermore, stability of the control model is proven. Simulation results are provided to demonstrate the effectiveness of the proposed control.