激光片光流动显示技术在高机动飞机布局设计中的应用

采用激光片光流动显示技术,针对某高机动布局飞机开展大迎角流动机理研究.结果表明激光片光流动显示技术具备捕捉复杂流动结构的能力,可以清晰观察双前翼布局大迎角下机头涡、第一前翼涡、第二前翼涡以及机翼涡等涡结构的生成、发展、融合等复杂流动结构的演化,并且揭示出涡结构扫略垂尾内侧使布局航向更加安定,偏转前翼将使旋涡绕流的涡心降低,造成布局升力提高,低头力矩增加.片光流动显示结果进一步表明,布局航向安定性不足,垂尾需要沿展向外移动,为布局深化设计提供了设计依据.     

Cryptanalysis and improvement of quantum broadcast communication and authentication protocol with a quantum one-time pad

The security of quantum broadcast communication(QBC) and authentication protocol based on Greenberger–Horne–Zeilinger(GHZ) state and quantum one-time pad is analyzed. It is shown that there are some security issues in this protocol.Firstly, an external eavesdropper can take the intercept–measure–resend attack strategy to eavesdrop on 0.369 bit of every bit of the identity string of each receiver without being detected. Meanwhile, 0.524 bit of every bit of the secret message can be eavesdropped on without being detected. Secondly, an inner receiver can take the intercept–measure–resend attack strategy to eavesdrop on half of the identity string of the other's definitely without being checked. In addition, an alternative attack called the CNOT-operation attack is discussed. As for the multi-party QBC protocol, the attack efficiency increases with the increase of the number of users. Finally, the QBC protocol is improved to a secure one.     

Implementation of Positive Operator-Valued Measure in Passive Faraday Mirror Attack

Passive Faraday-mirror(PFM) attack is based on imperfect Faraday mirrors in practical quantum cryptography systems and a set of three-dimensional Positive Operator-Valued Measure(POVM) operators plays an important role in this attack.In this paper,we propose a simple scheme to implement the POVM in PFM attack on an FaradayMichelson quantum cryptography system.Since the POVM can not be implemented directly with previous methods,in this scheme it needs to expand the states sent by Alice and the POVM operators in the attack into four-dimensional Hilbert space first,without changing the attacking effect by calculation.Based on the methods proposed by Ahnert and Payne,the linear-optical setup for implementing the POVM operators is derived.At last,the complete setup for realizing the PFM attack is presented with all parameters.Furthermore,our scheme can also be applied to realize PFM attack on a plug-and-play system by changing the parameters in the setup.     

利用奇、偶特征的正交几何构作的最优Cartesian认证码

利用奇、偶特征有限域上的正交几何构作出一类C artesian认证码,并且计算了它们的参数.并在假定按照等概率分布来选择编码规则下,求出了认证码的成功的模仿攻击概率和成功的替换攻击概率.作为一个推论,还得到了一些最优的C artesian认证码.     

An inviscid/viscous coupling approach for vortex flow field calculations

A new computational approach is developed for the analysis of vortex-dominated flow fields around highly swept wings at high angles of attack. In this approach an inviscid Euler technology is coupled with viscous models, similar to inviscid/boundary layer coupling. The viscous nature of the vortex core is represented by an algebraic model derived from the Navier–Stokes equations. The approach also accounts for the effects of the viscous shear layer near a wing surface through a modified surface boundary condition. The inviscid/viscous coupling consistently provides improved predictions of leading edge separation, vortex bursting and secondary vortex formation at relatively low computational cost. Results for several cases are compared with wind tunnel tests and other Euler and Navier-Stokes solutions.     

The Direction of Ring Fission of Unsymmetrically-substituted Succinic Anhydrides. 1. Interaction of α-Tetrahydrofurylsuccinic Anhydride with Benzylamine and 2,5-Xylidine

The reaction of -tetrahydrofurylsuccinic anhydride with amines proceeds regiospecifically at room temperature with the formation of N-substituted 2-(-tetrahydrofuryl)succinamic acids. On increasing the temperature the reaction direction is changed and the 3 isomer is mainly formed.     

Reaction of the dicobalt alkyne compound Co2(CO)6(μ-dmad) with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd). Spectroscopic properties, X-ray diffraction data, and thermal reactivity of the chelating isomer of Co2(CO)4(bpcd)(μ-dmad)

Treatment of Co₂(CO)₆(-dmad) (where dmad = dimethyl acetylenedicarboxylate) with the bidentate ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) in the presence of added Me₃NO affords the new alkyne compound Co₂(CO)₄(bpcd)(-dmad) in good yield. Both IR and ³¹P NMR spectroscopies indicate that the bpcd ligand is coordinated to a single cobalt center in a chelating fashion in solution. The solid-state structure of Co₂(CO)₄(bpcd)(-dmad) is identical to the solution structure Co₂(CO)₄(bpcd)(-dmad), as determined by X-ray diffraction analysis. Co₂(CO)₄(bpcd)(-dmad) crystallizes in the triclinic space group P-1, a = 10.7460(8) Å, b = 11.628(2) Å, c = 15.077(1) Å, = 95.831(9)°, = 91.205(7)°, = 101.526(9)°, V = 1834.7(3) ų, Z = 2, and d _calc = 1.514 g/cm³; R = 0.0489, R _w = 0.0528 for 2854 reflections with I > 3(I). The thermal reactivity of Co₂(CO)₄(bpcd)(-dmad) has been briefly explored by spectroscopic methods, and evidence is presented for the attack of one of the PPh₂ groups on an alkyne carbon atom in Co₂(CO)₄(bpcd)(-dmad) to from the zwitterionic hydrocarbyl compound Co₂(CO)₄(-²:²:¹:¹-(MeO₂C)=C(CO₂Me)PPh₂C=C(PPh₂)C(O)CH₂C(O)] upon thermolysis. The redox chemistry of both Co₂(CO)₄(bpcd)(-dmad) and Co₂(CO)₄[-²:²:¹:¹-(MeO₂C) C=C(CO₂Me)PPh₂C=C(PPh₂)C(O)CH₂C(O)] has been explored by cyclic voltammetery.     

NHCs as Neutral Donors towards Polyphosphorus Complexes

The first adducts of NHCs (=N-heterocyclic carbenes) with aromatic polyphosphorus complexes are reported. The reactions of [Cp*Fe(η⁵-P₅)] ( 1 ) (Cp*=pentamethyl-cyclopentadienyl) with IMe (=1,3,4,5-tetramethylimidazolin-2-ylidene), IMes (=1,3-bis(2,4,6-trimethylphenyl)-imidazolin-2-ylidene) and IDipp (=1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene) led to the corresponding neutral adducts which can be isolated in the solid state. However, in solution, they quickly undergo a dissociative equilibrium between the adduct and 1 including the corresponding NHC. The equilibrium is influenced by the bulkiness of the NHC. [Cp′′Ta(CO)₂(η⁴-P₄)] (Cp′′=1,3-di-tert-butylcyclopentadienyl) reacts with IMe under P atom abstraction to give an unprecedented cyclo-P₃-containing anionic tantalum complex. DFT calculations shed light onto the energetics of the reaction pathways.     

基于恶意攻击的多用户量子信令损伤模型及 诱骗态修复策略

本文提出了一个多用户量子信令传输系统,并详细阐述了信令在信道中的传输过程.研究了传输过程中信令受到第三方恶意攻击的损伤模型,并将诱骗态的思想引入量子信令安全的直接通信中,分析了采用不同光强来发送光脉冲,以克服光子数分裂攻击的问题,从而提高了信令传输的安全性.仿真结果表明,本文所提出的对多用户信令攻击的修复策略可有效地检测到光子数分裂数攻击,并增加了安全传输距离,从而保证信令传输过程安全有效的进行.