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Tunable optical second-order sideband effects in a parity-time symmetric optomechanical system

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Science China(Physics,Mechanics & Astronomy) 2020年第11期63卷 51-58页

作者： Xing Xiao QingHong Liao nanrun zhou WenJie Nie YongChun Liu Department of Electronic Information Engineering Nanchang UniversityNanchang 330031China State Key Laboratory of Low-Dimensional Quantum Physics Department of PhysicsFrontier Science Center for Quantum InformationTsinghua UniversityBeijing 100084China Department of Applied Physics East China Jiaotong UniversityNanchang 330013China

We theoretically investigate the optical second-order sideband generation(OSSG)in an optical parity-time(PT)symmetric system,which consists of a passive cavity trapping the atomic ensemble and an active *** with the double-passive system,it is found that near the exceptional point(EP),the efficiency of the OSSG increases sharply not only for the blue probepump detuning resonant case but also for the red *** experimentally achievable parameters,we study the effect of the atomic ensemble on the efficiency of the OSSG in the PT-symmetric *** numerical results show that the efficiency of the OSSG is 30%higher than that of the first-order sideband,which is realized easily by simultaneously modulating the atom-cavity coupling strength and ***,the efficiency of the OSSG can also be tuned effectively by the pump power,and the efficiency is robust when the pump power is strong *** study may have some guidance for modulating the nonlinear optical properties and controlling light propagation,which may stimulate further applications in optical communications.

关键词： second-order sideband effects parity-time symmetry optomechanical system

Joint Optimization Scheme for the Reconfigurable Intelligent Surface-Assisted Untrusted Relay Networks

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China Communications 2023年第12期20卷 19-29页

作者： Lihua Gong Wei Xu Xiaoxiu Ding nanrun zhou Qibiao Zhu Department of Electronic Information Engineering Nanchang UniversityNanchang 330031China Shanghai Key Laboratory of Integrate Administration Technologies for Information Security School of Information Security EngineeringShanghai Jiao Tong UniversityShanghai 200240China

To further improve the secrecy rate,a joint optimization scheme for the reconfigurable intelligent surface(RIS)phase shift and the power allocation is proposed in the untrusted relay(UR)networks assisted by the *** eavesdropping on the UR is interfered by a source-based jamming *** the constraints of unit modulus and total power,the RIS phase shift,the power allocation between the confidential signal and the jamming signal,and the power allocation between the source node and the UR are jointly optimized to maximize the secrecy *** complex multivariable coupling problem is decomposed into three sub-problems,and the non-convexity of the objective function and the constraints is solved with semi-definite *** results indicate that the secrecy rate is remarkably enhanced with the proposed scheme compared with the equal power allocation scheme,the random phase shift scheme,and the no-RIS scheme.

关键词： iterative optimization physical layer security reconfigurable intelligent surface untrusted relay secrecy rate

Audio-Visual Underdetermined Blind Source Separation Algorithm Based on Gaussian Potential Function

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China Communications 2014年第6期11卷 71-80页

作者： ZHANG Ye CAO Kang WU Kangrui YU Tenglong zhou nanrun Department of Electronic Information Engineering Nanchang University National Engineering Laboratory for Disaster Backup and Recovery Beijing University of Posts and Telecommunications

Most existing algorithms for the underdetermined blind source separation(UBSS) problem are two-stage algorithm, i.e., mixing parameters estimation and sources estimation. In the mixing parameters estimation, the previously proposed traditional clustering algorithms are sensitive to the initializations of the mixing parameters. To reduce the sensitiveness to the initialization, we propose a new algorithm for the UBSS problem based on anechoic speech mixtures by employing the visual information, i.e., the interaural time difference(ITD) and the interaural level difference(ILD), as the initializations of the mixing parameters. In our algorithm, the video signals are utilized to estimate the distances between microphones and sources, and then the estimations of the ITD and ILD can be obtained. With the sparsity assumption in the time-frequency domain, the Gaussian potential function algorithm is utilized to estimate the mixing parameters by using the ITDs and ILDs as the initializations of the mixing parameters. And the time-frequency masking is used to recover the sources by evaluating the various ITDs and ILDs. Experimental results demonstrate the competitive performance of the proposed algorithm compared with the baseline algorithms.

关键词： underdetermined blind sourceseparation interaural time difference interaural level difference visual information Gaussian potential function

Physical Layer Security for Wireless and Quantum Communications

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ZTE Communications 2013年第3期11卷 1-2页

作者： Jinhong Yuan Yixian Yang nanrun zhou the School of Electrical Engineering and Telecom munications University of New South Wales Information Security Center Beijing University of Posts and Telecommunications the National Engineering Laboratory for Disaster Backup and Recovery National Key Laboratory for Network and Information Defense the School of Information Engineering Nanchang University

his special issue is dedicated to security problems in wireless and quan-turn communications. Papers for this issue were invited, and after peer review, eight were selected for publication. The first part of this issue comprises four papers on recent advances in physical layer security forwireless networks. The second Part comprises another four papers on quantum com- munications.

关键词： Security Physical Layer Security for Wireless and Quantum Communications

Chlorine-assisted recovery of performance loss in MAPbI3 solar cells caused by low purity of PbI2

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Chlorine-assisted recovery of performance loss in MAPbI3 sol...

Chlorine-assisted Recovery of Performance Loss in CH3NH3PbI3 Solar Cells Caused by Low Purity of PbI2

第六届新型太阳能电池材料科学与技术学术研讨会

作者： Minlin Jiang Zuo Wang Yi zhou nanrun zhou Lihua Gong Institute of Advanced Study Nanchang University School of Information Engineering Nanchang University

This work reports an exciting discovery that the performance loss in MAPbI solar cells due to low purity of PbI can be fully recovered by adding a small amount of Cl source(MACl). The averaged efficiency of MAPbI solar cells using low purity PbI2 is 14.16%, while that using high purity PbI is 16.39%. Excitingly, the averaged efficiency of MAPbI solar cells using low purity PbI is boosted to 16.58% by adding a small amount of MACl into MAPbI precursor, which is comparable to that from high purity PbI(Fig. 1) [1]. Results from SEM and XRD indicate that the morphologies and structures of MAPbI thin films are not affected by the purity of PbI2 and the addition of small amount of Cl source. Further investigations using open-circuit voltage decay(OCVD) and admittance spectroscopy(AS) reveal that low purity of PbI leads to lower electron lifetime due to higher defect density, while the addition of Cl can suppress the defect density, resulting into higher electron lifetime. This discovery may offer a great opportunity for fabricating low-cost, high-efficiency perovskite solar cells using low purity feedstocks, which would definitely expedite the development of environment-friendly perovskite solar cells.

关键词： perovskite solar cells MAPbI3 PbI2 admittance spectroscopy

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Chlorine-assisted Recovery of Performance Loss in CH3NH3PbI3...

第五届新型太阳能电池学术研讨会

作者： Minlin Jiang Yi zhou nanrun zhou Lihua Gong Guangyong Li Institute of Advanced Study Nanchang University School of Information Engineering Nanchang University The Department of Electrical and Computer Engineering University of Pittsburgh

This work reports an exciting discovery that the performance loss in MAPbI solar cells due to low purity of PbI can be fully recovered by adding a small amount of CHNHCl(MACl). The averaged efficiency of MAPbI solar cells using low purity PbI is 14.16%, while that using high purity PbI is 16.39%. Excitingly, the averaged efficiency of MAPbI solar cells using low purity PbI is boosted to 16.58% by adding a small amount of MACl into MAPbI precursor, which is comparable to that from high purity PbI. Results from SEM and XRD indicate that the morphologies and structures of MAPbI thin films are not affected by the purity of PbI and the addition of small amount of Cl source. Further investigations using open-circuit voltage decay(OCVD) and admittance spectroscopy(AS) reveal that low purity of PbI leads to lower electron lifetime due to higher defect density, while the addition of Cl can suppress the defect density, resulting into higher electron lifetime. This discovery may offer a process route for fabricating low-cost, high-efficiency perovskite solar cells using low purity feedstocks, which would definitely expedite the development of environment-friendly perovskite solar cells.

关键词： perovskite solar cells MAPbI3 PbI2 admittance spectroscopy

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基于随机分数梅林变换的非线性图像加密算法

计算机应用 2013年第10期33卷 2865-2867,2894页

作者：张文全张烨周南润南昌大学电子信息工程系南昌330031

为了消除线性加密系统的安全隐患,提出了一种基于随机分数梅林变换的非线性图像加密算法。结合对数—极坐标变换和随机分数傅里叶变换构造了随机分数梅林变换,随机化过程用到的实对称随机矩阵由线性同余函数生成。输入的实值图像经随机... 详细信息

为了消除线性加密系统的安全隐患,提出了一种基于随机分数梅林变换的非线性图像加密算法。结合对数—极坐标变换和随机分数傅里叶变换构造了随机分数梅林变换,随机化过程用到的实对称随机矩阵由线性同余函数生成。输入的实值图像经随机分数梅林变换非线性加密,得到便于存储和传输的实值密文。该算法增加了线性同余函数的3个参数作为密钥,与分数梅林变换相比,随机分数梅林变换的分数阶密钥的敏感性更强。数值模拟表明该算法有较强的抗攻击能力,密钥灵敏度高,具有良好的安全性。

关键词：图像加密分数梅林变换分数傅里叶变换线性同余非线性加密

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基于相位恢复和混沌图的多图像并行加密算法

计算机工程与应用 2012年第23期48卷 63-66页

作者：张文全薛侠周南润南昌大学电子信息工程系南昌330031

基于相位恢复算法提出了分数傅里叶变换域的多图像加密算法。一组图像作为复值图像的振幅部分分别采用不同分数阶傅里叶变换加密到一个混沌图上;通过非线性加密过程产生的相位密钥与明文相关,所提的加密算法可以抵抗已知明文攻击,选择... 详细信息

基于相位恢复算法提出了分数傅里叶变换域的多图像加密算法。一组图像作为复值图像的振幅部分分别采用不同分数阶傅里叶变换加密到一个混沌图上;通过非线性加密过程产生的相位密钥与明文相关,所提的加密算法可以抵抗已知明文攻击,选择明文攻击和选择密文攻击。通过混沌系统还原的混沌图可以独立解密所有图像,加密容量较大。仿真结果验证了该方法的可行性、有效性和安全性。

关键词：分数傅里叶变换多图像加密混沌图相位恢复

基于Matlab的数字图像处理综合设计性实验

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实验技术与管理 2018年第11期35卷 48-53页

作者：龚黎华朱启标周志洪周南润南昌大学电子信息工程系江西南昌330031 上海市信息安全综合管理技术研究重点实验室上海200240 上海交通大学网络空间安全学院上海200240

针对数字图像处理课程的实验教学,设计了一套以培养学生学习兴趣和科研能力为目标的综合设计性实验项目。该项目基于Matlab软件平台,对现有的数字图像处理课程中的综合性和设计性实验进行了深入研究与合理整合,形成具有创新实践特点的... 详细信息

针对数字图像处理课程的实验教学,设计了一套以培养学生学习兴趣和科研能力为目标的综合设计性实验项目。该项目基于Matlab软件平台,对现有的数字图像处理课程中的综合性和设计性实验进行了深入研究与合理整合,形成具有创新实践特点的综合设计性实验项目。教学实践的结果表明,具有创新性质的综合设计性实验项目的开展,有利于学生的实践动手能力和创新设计能力的培养。

关键词：数字图像处理实验项目图像加密 Matlab