一种改进的调制分类器设计方案

通过比较几种常用调制分类器的优缺点,提出了一种新的调制分类器设计方案.它采用高效稳健的遗传算法,先筛选出一高质量的最小特征子集,再对RBF神经网络的隐层节点中心值进行进化优选.仿真结果证实了该方法的优越性.此外,还对调制分类器用于移动数字电视的研究方向提出了建议.     

基于DAB/DMB系统的模式检测及帧同步技术

针对数字多媒体广播(DAB/DMB)系统,提出了一种可实际应用的信号模式检测和时域帧同步技术,该方法是基于信号空符号的能量自适应检测方法(Energy-Based Detection,EBD).仿真结果显示其同步性能良好,可推广应用于其他具有多种传输模式的OFDM系统的模式检测及帧同步.与最大似然相关方法相比,实现复杂度低,硬件资源占用少.     

多用户MIMO-OFDM系统中一种子载波分配算法

介绍了多用户MIMO-OFDM系统中的Hungarian子载波分配算法,然后针对其计算复杂度过高的缺陷,提出一种局部最优的子载波分配算法,并与Hungarian子载波分配算法进行仿真比较。结果表明,该算法使系统总数据速率仅下降1．7％,而其计算复杂度却大幅减小,提高了资源分配的效率,符合高速无线系统资源实时分配的要求。     

势垒对称性对锆钛酸铅(PZT)薄膜铁电及光伏性能的影响

文章主要研究对称(ITO/PZT/ITO)与非对称(Pt/PZT/ITO)势垒结构对锆钛酸铅(PZT)薄膜铁电及光伏性能的影响.实验发现,势垒对称性差异直接影响材料电滞回线,ITO/PZT/ITO结构的剩余极化强度(Pr)更大,对称性更好,饱和度更高.测试光照与暗态时两种结构Pr的变化,结果显示两种结构的Pr均增大,分析光照时Pr增大的原因,发现两种结构的漏电流在光照时均明显变大,但两种结构的净极化强度(△P)在光照时表现出差异,即对于ITO/PZT/ITO结构光照时△P基本不变,而Pt/PZT/ITO结构光照△P变小.因此得出光照时△P的变化受势垒对称性的影响,但光照时Pr的增大主要源于漏电流的增加而非△P.此外还对两种结构的光伏性能进行了研究,发现势垒的对称性同样影响材料的光伏特性,Pt/PZT/ITO结构的开路电压和短路电流密度明显高于ITO/PZT/ITO结构.     

General Eight-Vertex Model and Braid Group Representation

The braid group representations (BGRs) corresponding to general eight-vertex model are obtained for the case in which the total spins are not conserved. A Yang-Baxterization scheme is applied to obtain from these BGRs.     

HEAVY ION COLLISION DYNAMICS IN FERMI DOMAIN (Ⅱ) DYNAMICS DEPENDENCE OF IMPACT PARAMETER

The peripheral collision mechanisms have been systemic ally studied via the Boltzmann-Uehling-Uhlenbeck theory in the Fermi domain for ²⁰Ne+²⁰Ne collision system.The characters of energy dependence and the intermediate mass fragment production in the process of incomplete deep inelastic collision were discussed.     

Cyclic Representation of the q-Deformed Heisenberg-Weyl Superalgebras and the q-Boson-Fermion Realization of Cyclic Represent at ion of Quantum Superalgebra Uqsl(m,n)

A cyclic representation of the q-deformed Heisenberg-Weyl superalgebras is constructed. By making use of this cyclic representation we study the cyclic representations,of quantum superalgebras in terms of their q-boson-fermion realizations with U_qsl(m, n) as an example. Two different q-boson-fermion realizations of U_qsl(m, n) are used and thus two inequivalent cyclic representations of U_qsl(m, n) are obtained.     

Yang-Baxterization and New Solutions Associated with SU(2) Tensorial Space Vj⊗V1/2*

By applying extended diagrammatic technique to SU(2) tensorial space V^j⊗V^1/2 new solutions of the correspondent braid group representations and their Yang-Baxterization are established. The explicit forms of the new solutions of Yang-Baxter equation for j = 1 are given. Through this example the general feature of this new type of solutions is figured out.     

辐射引发丙烯腈－丙烯酸甲酯－衣康酸三元沉淀共聚合

辐射引发丙烯腈－丙烯酸甲酯－衣康酸三元沉淀共聚合张志成,葛学武,葛敏,张健（中国科学技术大学应用化学系,合肥,２３００２６）关键词聚丙烯腈,超高分子量,辐射引发,沉淀共聚合制备高性能的碳纤维,首先要制备优良的丙烯腈基原丝（ＳＡＦ）．ＳＡＦ聚合物具有超...     

The Properties of Nuclear Collective Flow in the Intermediate and High Energy Heavy-ion Collisions

In this paper the static characteristic of the nuclear matter characterized by the interior pressure and the binding energy as a function of density is studied with different interactions.By taking into account both the momentum dependence potential and the nuclear medium effect,the dependence of the nuclear collective flow on the impact parameters and the bombarding energies is investigated systematically with BUU dynamical calculations.The nuclear equation of state is better understood by comparing the calculation results with the experiments.