A quantum circuit design of AES requiring fewer quantum qubits and gate operations

Advanced Encryption Standard (AES) is one of the most widely used block ciphers nowadays, and has been established as an encryption standard in 2001. Here we design AES-128 and the sample-AES (S-AES) quantum circuits for deciphering. In the quantum circuit of AES-128, we perform an affine transformation for the SubBytes part to solve the problem that the initial state of the output qubits in SubBytes is not the |0>^⊗8 state. After that, we are able to encode the new round sub-key on the qubits encoding the previous round sub-key, and this improvement reduces the number of qubits used by 224 compared with Langenberg et al.’s implementation. For S-AES, a complete quantum circuit is presented with only 48 qubits, which is already within the reach of existing noisy intermediate-scale quantum computers.     

冲角工况下列车车轮损伤机理研究

曲线通过和蛇行运动时将会在轮轨间产生一定的冲角,为探究列车车轮在冲角工况下的损伤机理,利用JD-1轮轨模拟试验机对列车车轮进行滚动接触疲劳试验.结果表明:在冲角工况下车轮试件磨痕的不同区域存在不同的损伤机理,按损伤机理的不同可以将其分为塑性堆积区、疲劳损伤区和磨损区三个区域.在应力发生剧烈变化且应力方向由高应力区指向低应力区的区域将会出现材料的塑性堆积,并且在堆积处产生疲劳裂纹.滚动接触下的疲劳裂纹可以萌生于表面和亚表面,在较强应力作用下,车轮材料的晶粒发生了明显的细化,在横截面上呈现出纤维状组织.     

Convolutional Neural Network Approach for Multispectral Facial Presentation Attack Detection in Automated Border Control Systems

Automated border control systems are the first critical infrastructure point when crossing a border country. Crossing border lines for unauthorized passengers is a high security risk to any country. This paper presents a multispectral analysis of presentation attack detection for facial biometrics using the learned features from a convolutional neural network. Three sensors are considered to design and develop a new database that is composed of visible (VIS), near-infrared (NIR), and thermal images. Most studies are based on laboratory or ideal conditions-controlled environments. However, in a real scenario, a subject’s situation is completely modified due to diverse physiological conditions, such as stress, temperature changes, sweating, and increased blood pressure. For this reason, the added value of this study is that this database was acquired in situ. The attacks considered were printed, masked, and displayed images. In addition, five classifiers were used to detect the presentation attack. Note that thermal sensors provide better performance than other solutions. The results present better outputs when all sensors are used together, regardless of whether classifier or feature-level fusion is considered. Finally, classifiers such as KNN or SVM show high performance and low computational level.     

Nucleophilic Activation of Sulfur Hexafluoride by N-Heterocyclic Carbenes and N-Heterocyclic Olefins: A Computational Study

Sulfur hexafluoride (SF₆) is considered as a potent greenhouse gas, whose effective degradation is challenging. Here we report a computational study on the nucleophilic activation of sulfur hexafluoride by N-heterocyclic carbenes and N-heterocyclic olefins. The result shows that the activation of SF₆ is both thermodynamically and kinetically favorable at mild condition using NHOs with fluoro-substituted azolium and sulfur pentafluoride anion being formed. The Gibbs free energy barrier during the activation of SF₆ has a linear relationship with the energy of HOMO of substrates, which could be a guideline for applying those compounds that feature higher energy in HOMO to activate SF₆ in high efficiency.     

大环多胺金属模拟酶催化水解梭曼机理研究

为解决生物酶在战场应用环境中易失活且环境耐受性差的问题,我们合成了大环多胺双锌模拟酶配合物-2,6-双{[双(2-羟乙基)氨基]甲基}-4-甲基酚(Zn L2).Zn L2对GD(Soman,梭曼)具有较高的催化活性,能够实现多次催化循环,并且在Zn L2与GD化学计量比为(0.56∶1)的条件下水解率为100%.使用高效液相色谱-质谱与核磁共振确定催化产物为甲氟膦酸酯、甲氟膦酸、甲基膦酸频哪酯与甲基膦酸,说明Zn L2水解GD为双平行反应,反应途径分别为GD的P—F与P—O键的断裂.建立在实验的基础上,使用密度泛函理论(DFT)的B3LYP方法,从P—O与P—F键断裂这两个平行反应方向对催化过程进行计算.计算结果表明:Zn L2上Ot末端醇盐作为一个碱试剂去激活水分子,使其成为羟基并作为亲核试剂进攻中心磷原子,形成一个五配位的磷酰中间体,通过进一步亲核进攻水解中间体形成最终P—O与P—F键断裂产物.Zn L2催化GD水解的活化能为分别为5.6 kcal/mol(P—F键断裂)和11.5 kcal/mol(P—O键断裂),说明P—O键断裂过程是GD酶促水解反应的速控步骤.     

Multiple re-configurable intelligent surfaces based physical layer eavesdropper detection for V2I communications

Inspired by the promising potential of re-configurable intelligent surface (RIS)-aided transmission in achieving the vision of 6th Generation (6G) network, we analyze the security model for a vehicular-to-infrastructure (V2I) network by considering multiple RISs (M-RIS) on buildings to act as passive relays at fixed distances from a source. In addition, multiple eavesdroppers are presented in the vicinity of the intended destination. Our aim is to enhance the secrecy capacity (SC) and to minimize secrecy outage probability (SOP) in presence of multiple eavesdroppers with the help of M-RIS in V2I communications. We propose a key-less physical layer security using beam-forming by exploiting M-RIS. The proposed approach assumes the concept of detecting eavesdroppers before the information can be transmitted via beam-forming by utilizing M-RIS. The results reveal that with consideration of M-RIS and beam-forming, the achievable SC and SOP performance is significantly improved while imposing minimum power consumption and fewer RIS reflectors.     

俯仰振荡三角翼前缘涡破碎的流动显示

前缘后掠角为６５°和７０°的两个平板三角翼作俯仰振荡运动，前缘涡破碎的流动显示实验研究在南京航空航天大学１米低速风洞中进行。俯仰振荡运动的攻角范围为０°～６０°，折合频率为０．０３和０．０６。采用四氯化钛发烟技术显示前缘涡核轨迹及涡破碎位置。流动显示图形采用相位锁定照相记录。实验结果表明大幅俯仰振荡三角翼的动态涡破碎的弦向位置明显滞后于相应攻角下的静态位置，此滞后量随折合频率增加而增大。本文也根据测得的涡破碎位置随攻角变化曲线讨论了涡破碎位置的传播速度     

细长体背风面横向非对称分离的研究

用数值模拟方法研究了超声速情况下，无限长细长体背风面的涡结构。数值模拟的出发方程和计算格式分别为全Ｎ－Ｓ方程和二阶空间精度的ＴＶＤ格式。数值结果给出了圆锥、半球柱体和椭圆锥在不同攻角下的流场结果。结果表明圆锥在攻角α＝１５°，２０°和２５°时背风面呈现明显的稳定非对称横向分离，而半球柱体和椭圆锥在３２．５°和２５°时背风面均未出现非对称的横向分离结构。     

Study of the aerodynamic stability of a blunt cone with a side flap in a hypersonic flow

The stationary and time-dependent aerodynamic coefficients of a slender blunt cone with a flap located near the base section of the model are experimentally investigated. The freestream parameters (M_∞ = 6, Re _L = 0.88 × 10⁷, and γ = 1.4) ensured a turbulent regime of flow over the conical surface and the flap. At high angles of attack (α ～ 10°) laminar-turbulent transition is observable in the separation zone on the leeward side of the body. Emphasis is placed on the determination of the trimming angles of attack for different positions of the center of rotation and the static and dynamic stability coefficients (the model oscillation damping coefficient).     

前体非对称涡高风速烟雾显示技术

通过在细长旋成体模型机身的不同位置设置出烟孔，使用新型发烟装置对模型注入雾化油 滴，采用激光片光法在常规风洞中高风速(60m/s)条件下得到清晰、完整而稳定的截面涡 结构图像. 并通过同状态标定法和等比例网格法发展了简易涡位定量测量技术，为前体非对 称涡Re数效应的研究提供了重要的技术平台.