摘要：This study presents two multimode stepped-impedance structures to design single-and dual-band filters. Transmission zeroes are introduced for the single-band filter by using dual-mode stepped-impedance resonators. The single-band filter with high selectivity is centered at 6.02 GHz and has a fractional bandwidth （FBW） of 25.6%. Four stubs （two low frequency and two high frequency ones） are connected to the rectangular patch in the center to construct a quadruple-mode resonator. The independent conditions of the center frequencies of the high and low bands of the resonator are analyzed. A dual-band filter, which operates at 1.53 GHz and 2.44 GHz with FWBs of 12.1% and 14.1%, respectively is designed. The single-and dual-band filters are both fabricated with double-sided YBCO films and they can be used in mobile and satellite communications.

摘要：Confined low dimensional charges with high density such as two-dimensional electron gas(2 DEG)at interfaces and charged domain walls in ferroelectrics show great potential to serve as functional elements in future ***,stabilization and control of low dimensional charges is challenging,as they are usually subject to enormous depolarization ***,we demonstrate a method to fabricate tunable charged interfaces with~77°,86°and 94°head-to-head polarization configurations in multiferroic Bi Fe O_(3) thin films by grain boundary *** adjacent grains are cohesively bonded and the boundary is about 1 nm in width and devoid of any amorphous ***,the polarization remains almost unchanged near the grain boundaries,indicating the polarization charges are well compensated,i.e.,there should be two-dimensional charge gas confined at grain *** the tilt angle of the grain boundaries enables tuning the angle of polarization configurations from 71°to 109°,which in turn allows the control of charge density at the grain *** general and feasible method opens new doors for the application of charged interfaces in next generation nanoelectronics.

摘要：由非平衡驱动的热传导通过物理接触传递内部的热能.描述热传导的数学方程是一个典型的偏微分方程.它广泛存在于各种工程问题中,例如粒子扩散、航天器设计和稀释制冷机运行.本文提出了一种显著优于经典算法的热传导量子算法,并在量子硬件上演示了热传导过程.作者通过一个辅助量子比特构造的对称系统来表示原始热传导系统,使得量子线路的复杂度减少到离散格点数量的对数多项式量级.与现有的基于Harrow-Hassidim-Lloyd的线性方程算法相比,本文的方法直接演化线性过程,不进行相位估计,避免相位估计涉及复杂的量子门操作和较大的输出误差,便于在目前的量子硬件实现,显示了该算法是实验友好特性.并且,作者在核自旋量子处理器上实现了两端恒温和绝热条件的一维热传导过程,温度的时空分布与理论预言很好的吻合.该算法可以自然地应用于可归约为热方程的物理过程.

摘要：quantum secure direct communication(QSDC)attracts much attention for it can transmit secret messages directly without sharing a *** this article,we propose a one-step QSDC protocol,which only requires to distribute polarization-spatial-mode hyperentanglement for one *** this QSDC protocol,the eavesdropper cannot obtain any message,so that this protocol is unconditionally secure in *** protocol is a two-way quantum communication and has high capacity for it can transmit two bits of secret messages with one pair of *** entanglement fidelities of both polarization and spatial-mode degrees of freedom being 0.98,the maximal communication distance of this onestep QSDC can reach about 216 *** can also be used to generate the *** this regard,the key generation rate is estimated about 2.5 times of that in the entanglement-based QKD with the communication distance of 150 *** the help of future quantum repeaters,this QSDC protocol can provide unconditionally secure communication over arbitrarily long distance.