声纳湿端数据远传DWDM光电交换模块设计

声纳的应用极其广泛,海洋渔业以及军事应用使得声纳技术得到了大力发展。声纳湿端数据传输的可靠性、实时性是声纳系统性能得到保障的前提。为此设计一用于声纳湿端数据远传的DWDM光电交换模块。在该模块中,使用以太网交换芯片和两个DWDM光模块对数据进行多路转发并实现光通路的冗余备份,提升了系统可靠性的同时使网络拓扑更为灵活。由于DWDM光模块可将电信号转换为波长可选定的光信号,故通过若干该模块协同使用,可实现多路光信号复用即同时传输多条声纳水下阵缆的数据。经实际开发与测试,该模块以太网业务性能指标符合设计需求,且该模块已在某声纳工程项目中得到了应用,并可为其他领域数据远传工程应用提供设计参考。     

On m- $$\sigma$$ σ -embedded subgroups of finite groups

Acta Mathematica Hungarica - Let $$\sigma =\{\sigma_i |i\in I\}$$ be some partition of the set of all primes $$\mathbb{P}$$ and G be a finite group. A group is said to be $$\sigma$$ -primary if it...     

低汉明重量序列的分布

数n的汉明重量是指n的二进制字符串表达式中数字1的个数,用Ham(n)来表示.低汉明重量序列在密码系统和编码理论中有非常广泛的应用.本文建立了低汉明重量数的序列表达式,并且利用指数和的上界以及Erd?s-Turán不等式证明低汉明重量序列的均匀分布性质,从而确保密码算法的随机性和运算效率.     

Sensitivity of Exponents of Three-Power Laws to Hybrid Ratio in Weighted HUHPM

The sensitivity of exponents of three-power laws for node degree, node strength and edged weight to hybrid ratio are studied analytically and numerically in the weighted harmonious unifying hybrid preferential model （HUHPM）, which is extended from an-weighted hybrid preferential attachment model we proposed previously [Chin. Phys. Lett. 22 （2005）719]. Our weighted HUHPMs plus the Barrat-Barthelemy-Vespignani model and the traffic-driven evolution model, respectively, are taken as two typical examples for demonstration and application of the HUHPM.     

纳米晶复合永磁材料的交换耦合相互作用和磁性能

本介绍了纳米磁性材料晶粒交换耦合相互作用的有关理论。采用不同模型讨论了晶粒交换耦合相互作用对纳米单相软磁材料、永磁材料及双相复合永磁材料磁性能的影响。简述了用δM（H）曲线和不可逆磁导率的变化研究晶粒交换耦合相互作用及反磁化过程的方法。讨论了合金分配比、添加元素、制备及热处理工艺对磁体硬磁性能的影响。从理论和实验两方面分析、研究了纳米复合永磁材料的反磁化过程和矫顽力机制。     

Involutive Solutions and Commutator Representations of the Dirac Hierarchy

ConsidertheDiracspectralproblemwherep,qaretwopotentials,Aisaspectralparameter.L*isaninjectivehomomorphism.ThefunctionalgradientVA=(2RR,ri-of)TofeigenvalueAwithrespecttop,qsatisfiesarecalledtheLenard'soperatorpairof(1).Theorem1LetG(1)(x),G(z)(x)betwoarbitarysmoothfunctions,G=(G(1),G(2))".ThenthefollowingoperatorequationwithrespecttoV=V(G),possessestheoperatorsolutionwhereL.'-jisthecommutator;L=L(p,q),K,Jaredefinedby(1)l(4)respectively.ProofSubstitute(6)into(5),directlycalculate.Defin…     

Subbarrier Complete Fusion-Fission Reactions of 16)O+232Th

We have succeeded in isolating the complete arising from complete fusion-fission in terms of the fragment folding angle technique,and measured complete fusion-fission cross sections and fragment angular distributions for the ¹⁶O+²³²Th system in the center-of-mass energies between 72.61 and 80.11 MeV.The observed fission excitation function is in quite good agreement with the expectation of the coupled-channels theory.However,the measured fragment angular distributions are more anisotropic than the predictions of both the saddle-point transition-state model and scission model.     

苄基保护甘露糖羧酸酯的NMR研究

应用NMR技术研究了1-0-(3,5-二硝基苯甲酰基)-2、3、4、6-四-0-苄基-D-吡喃甘露糖的α、β异构体的构型和糖环上碳氢归属情况,总结了苄基保护甘露糖羧酸酯构型的确证方法及影响糖环上碳氢化学位移的一些规律;并对其它13种四苄基甘露糖羧酸酯的NMR谱进行了研究,提供了这些化合物的¹³C和¹H NMR数据.     

准坐标下完整力学系统的非Noether守恒量——Hojman定理的推广

利用时间不变的无限小变换下的Lie对称性，研究准坐标下完整力学系统的一类新守恒量.建立系统的运动微分方程，给出无限小变换下的Lie对称性确定方程.将Hojman定理推广，并举例说明结果的应用. 关键词： 准坐标 完整力学系统 Lie对称性 非Noether守恒量 Hojman定理     

Effects of Si doping on the structural and electrical properties of Ge2Sb2Te5 films for phase change random access memory

The effects of Si doping on the structural and electrical properties of Ge₂Sb₂Te₅ film are studied in detail. Electrical properties and thermal stability can be improved by doping small amount of Si in the Ge₂Sb₂Te₅ film. The addition of Si in the Ge₂Sb₂Te₅ film results in the increase of both crystallization temperature and phase-transition temperature from face-centered cubic (fcc) phase to hexagonal (hex) phase, however, decreases the melting point slightly. The crystallization activation energy reaches a maximum at 4.1 at.% and then decreases with increasing dopant concentration. The electrical conduction activation energy increases with the dopant concentration, which may be attributed to the increase of strong covalent bonds in the film. The resistivity of Ge₂Sb₂Te₅ film shows a significant increase with Si doping. When doping 11.8 at.% of Si in the film, the resistivity after 460 °C annealing increases from 1 to 11 mΩ cm compared to the undoped Ge₂Sb₂Te₅ film. Current-voltage (I-V) characteristics show Si doping may increase the dynamic resistance, which is helpful to writing current reduction of phase-change random access memory.