Constructions of Beyond-Birthday Secure PRFs from Random Permutations,Revisited

In CRYPTO 2019, Chen et al. showed how to construct pseudorandom functions (PRFs) from random permutations (RPs), and they gave one beyond-birthday secure construction from sum of Even-Mansour, namely SoEM22 in the single-key setting. In this paper, we improve their work by proving the multi-key security of SoEM22, and further tweaking SoEM22 but still preserving beyond birthday bound (BBB) security. Furthermore, we use only one random permutation to construct parallelizable and succinct beyond-birthday secure PRFs in the multi-key setting, and then tweak this new construction. Moreover, with a slight modification of our constructions of tweakable PRFs, two parallelizable nonce based MACs for variable length messages are obtained.     

Classical and Bayesian Inference of an Exponentiated Half-Logistic Distribution under Adaptive Type II Progressive Censoring

The point and interval estimations for the unknown parameters of an exponentiated half-logistic distribution based on adaptive type II progressive censoring are obtained in this article. At the beginning, the maximum likelihood estimators are derived. Afterward, the observed and expected Fisher’s information matrix are obtained to construct the asymptotic confidence intervals. Meanwhile, the percentile bootstrap method and the bootstrap-t method are put forward for the establishment of confidence intervals. With respect to Bayesian estimation, the Lindley method is used under three different loss functions. The importance sampling method is also applied to calculate Bayesian estimates and construct corresponding highest posterior density (HPD) credible intervals. Finally, numerous simulation studies are conducted on the basis of Markov Chain Monte Carlo (MCMC) samples to contrast the performance of the estimations, and an authentic data set is analyzed for exemplifying intention.     

O4对利用天顶散射光法测量大气组分含量的影响研究

通过实验证明是否考虑O₄的存在对利用天顶散射光测量大气组分含量的结果存在影响.介绍了天顶散射光的观测原理、实验仪器、测量方法、光谱处理以及浓度反演过程.用具体的实验数据说明考虑O₄在实验波段内的吸收能提高NO₂和O₃浓度反演结果的准确性.同时将观测得到的臭氧垂直柱密度与美国TOMS观测数据进行了对比. 关键词： 4')" href="#">O₄ 臭氧 天顶散射光 DOAS     

高生长速度条件下的“层片↔棒状”共晶转变机理研究

低速生长条件下, 共晶“层片↔棒状”转变只由两相的体积分数控制. 高速情况下, 这种转变有时亦发生, 其转变机理不清楚. 本文应用竞争生长准则, 结合高速生长条件下层片共晶和棒状共晶生长模型研究了生长速度引起的“层片↔棒状”转变机理. 结果显示: 体积分数在临界值附近很小的范围内, 生长速度和溶质配分系数的增大可引起“棒状→ 层片”共晶转变; 而当体积分数远离临界值时, 转变不发生. 生长速度名义上引起“层片↔棒状”共晶转变实际上是由生长速度变化引起的体积分数的变化导致的. 关键词： “层片↔棒状”共晶转变 竞争生长 生长速度 体积分数     

Structures and stabilities of the donor–acceptor complexes HXPY (X=Al,B; Y=H,F, OH)

The optimized geometries, complexation energies, etc. of HXPY (X?=?Al, B; Y?=?H, F, OH) donor–acceptor complexes have been investigated at the B3LYP/6-311+G(d,p), MP2/6-311+G(d,p) and/or CCSD(T)/6-311+G(d,p) levels. The results show that HBPY (Y?=?H, F, OH) is more stable than the corresponding HAlPY (Y?=?H, F, OH), F (or OH) substitution on phosphorus results in decreasing complex stability, and the stronger the electron-attracting nature of the substitution atom, the more stable the complex. Moreover, the thermodynamic and kinetic properties of the formation reaction of these donor–acceptor complexes were also examined within the temperature range 200–800?K using the general statistical thermodynamics and Eyring transition state theory with Wigner correction. It is concluded that the formation of HBPY is thermodynamically favoured over that of the corresponding HAlPY, especially at low temperature, and is kinetically favoured over that of the relevant HAlPY (Y?=?H, F, OH), especially at high temperature.     

生成超重核的熔合反应中的动力学形变效应

利用包含动力学势能面的双核模型对超重核的生成机制中的一些问题进行了研究。对双核系统的粒子交换势能面进行的计算结果表明,反应过程中原子核动力学形变对于粒子交换势能面的结构有显著的影响。进一步计算了生成超重核的熔合几率,结果显示,原子核的动力学形变导致内熔合位垒升高,进而明显降低了生成超重核的熔合几率。Some aspects in the fusion mechanism for the production of superheavy nuclei are investigated with the dinuclear system model with dynamical potential energy surface. The calculation results about the potential energy surface indicate that the inclusion of nuclear dynamical deformation affects the structure of potential energy surface significantly.The investigation on the fusion probability to synthesize superheavy nuclei indicates that the fusion probability decreases significantly due to the increase of the inner fusion barrier for the inclusion of the nuclear dynamical deformation.     

Morphology Development in Multi‐Component Polymer Blends: I Composition Effect on Phase Morphology in PP/PET Polymer Blends

The relationship of the phase morphology of polypropylene/polyethylene‐terephthalate (PP/PET) blends and their corresponding compatibilized blends with composition was investigated using digital image analysis. A diameter, d _g , was defined and calculated to discuss the phase morphology of this polymer blend system. A figure‐estimation method was introduced to determine the width of the distribution of d _g . Based on the method, it is proven that the distribution of d _g obeys a log‐normal distribution and consequently, the distribution width, σ was calculated. Further, a fractal dimension, D _f , was introduced to describe the distribution of main sizes of the particles of the dispersed phase. The results showed that, while d _g increased with the concentration of the dispersed phase, σ and D _f show different dependence relations on composition;σ increases monotonously but D _f shows a maximum at a PET content of 30%, indicating that, even though the whole size distribution is much broader, the distribution of the main body of size becomes more uniform when the content of PET is less than 30%.     

The mass of the nucleus148Dy

Usingγγ coincidences theEC(K)/β ⁺ ratio for theβ decay¹⁴⁸Dy→¹⁴⁸Tb has been determined.¹⁴⁸Dy has been produced through the irradiation of⁹³Nb with 249 MeV⁵⁸Ni ions. The mass of¹⁴⁸Dy has been deduced. With the help of knownQα values the masses of¹⁵²Er,¹⁵⁶Yb,¹⁶⁰Hf and¹⁶⁴W have been obtained. The experimental masses are compared with different current mass formulae.     

离散Lyapunov矩阵方程X—AXB=C的一种数值解法

本文提供了求解离散Lyapunov矩阵方程的一种数值解法。首先讨论了系数矩阵为三对角形矩阵的公式解法,然后通过相似变换,将该方法推广到一般情形。     

Gain Assisted Raman Induced Classical and Quantum Talbot Imaging

2D Raman generated classical and quantum Talbot imaging is proposed in a three-level gain assisted system. First, a 2D Raman induced grating (RIG) will be constructed by modulating transmission function in the weak probe channel using a strong control standing wave field. Furthermore, RIG will diffract a probe field, by shining a probing light beam on an optically generated lattice within a rubidium vapor cell. This study uses gain assisted Raman medium [Nature 406 , 277 (2000)] to examine classical and quantum Talbot imaging. In the case of Raman-induced classical imaging, the diffraction pattern repeats itself at planes with integer multiple Talbot lengths. Additionally, by taking into account entangled photon pairs, the scenario of Raman-induced quantum imaging is investigated. This study also looks at the RIG's amplitude and phase information with adjustable image size variation. As a result of the gain feature and zero absorption, this system is anticipated to be more suitable from the perspective of application. This analysis may pave the way for further research into the Talbot effect's nonlinear and quantum dynamical properties. Also, it provide a non-destructive, lensless method for imaging very cold atoms or molecules.