基于CM8870小型程控交换机设计

给出基于CM8870双音多频解码器的小型程控交换机设计。简单介绍了双音多频信号组成与CM8870解码器芯片的结构与功能,对CM8870解码器的收号过程进行了详细说明。最终给出了利用SM8951单片机作为交换机控制器控制小型交换机进行通信的完整电路设计。该设计经实现后证实系统可靠、稳定,能够顺利完成交换机的电路交换功能。     

Copper stress migration at narrow metal finger with wide lead

Copper stress migration (SM) at narrow metal finger connected with wide lead is investigated in this work. Voiding phenomenon is explored with respect to specific failure site. Metal geometric factors including lead width, lead length and finger length are also discussed in terms of SM failure rates. Meanwhile, in order to study the failure mechanism, a finite element analysis (FEA) is conducted to evaluate the influences from vacancy migration path, hydrostatic stress gradient and different metal geometries. As a result, a characterization regarding SM at narrow metal finger with wide lead is obtained for the reference of reliability assessment and process improvement.     

带消息填充的 29 步 SM3 算法原根和伪碰撞攻击简

基于中间相遇攻击技术,提出了一种针对密码杂凑函数SM算法的原根攻击和伪碰撞攻击方法,给出了从第1步开始的带消息填充的29步SM3算法的原根攻击和伪碰撞攻击。结果表明：对于29步SM3算法的原根攻击的时间复杂度为2254;对于29步SM3伪碰撞攻击的时间复杂度为2125。说明从第1步开始的带消息填充的29步SM3算法不能抵抗原根攻击和伪碰撞攻击。     

Microstructure and thermal expansion properties of invar-type Cu-Zn-Al shape memory alloys

The effects of grain size, volume fraction of the α (fcc) phase in the β (bcc) matrix, and thermal stability on low thermal expansion (LTE) properties of Cu-Zn-Al shape memory (SM) alloys induced by cold rolling were investigated by dilatometry, optical microscopy, differential scanning calorimetry, and electrical conductivity measurements. The alloys with the larger grains showed a superior two-way memory (TWM) effect, wider LTE temperature intervals with excellent thermal stability under 80°C. The α+β two-phase alloys also exhibited a good combination of cold workability and LTE properties. These results suggest that the Cu-Zn-Al alloys with high electrical conductivity of about 20% International Annealed Copper Standard (%IACS) have high potential as a new class of Invar alloys that can be applied in various fields.     

Block mapping spatial modulation scheme for MIMO systems

In this paper,a block mapping spatial modulation(BMSM)scheme is proposed to increase the transmit rate of multiple-input multiple-output(MIMO)wireless communication systems.In the BMSM scheme,the information to be transmitted is mapped into different combinations of transmit antenna indices and distinct constellation symbols at each time instant.Multiple transmit antennas are activated,which is different from spatial modulation(SM)and generalised spatial modulation(GSM)techniques,and also the information bi...     

基于DEJD模型的人口寿命预测及SM债券定价

人口老龄化背景下的长寿风险,将会给国家养老保障体系带来极大的经济负担.如何度量和管理长寿风险,己成为近年来世界各国关注和研究的焦点.本文基于我国人口死亡率数据,在Lee-Carter模型的基础上,引入DEJD模型刻画时间序列因子的跳跃不对称性,并证实了 DEJD模型比Lee-Carter模型在拟合时间序列因子时更为有效...     

PHS网络优化中短信自动派障系统的设计与实现

介绍了短信自动派障系统的操作流程以及软硬件结构.实验表明该系统可以提高基站在网运营率;缩短故障基站的故障时间.     

Tests of the standard model and search for new physics using flavor

The vast amount of flavor physics data available to date allows probing the presence of physics beyond the standard model through precision measurements of CP violating and CP conserving processes involving B, D, and K mesons. The information extracted from these measurements allows the characterization of physics beyond the standard model in a complementary way with respect to the direct searches at the Tevatron and the LHC. We review the status of the search for new physics with flavor-related observables. We discuss the status of the unitarity triangle analysis beyond the standard model: the inclusion of the recent measurements of B_s decays from the Tevatron experiments point to a discrepancy from the standard model expectation. In addition, we discuss the impact of O(Λ_QCD/m_b) corrections to the perturbative calculation of charmless hadronic B decays. These corrections can explain the puzzling values of direct CP asymmetries in B→Kπ decays within the standard model. These corrections cannot explain values of sin2β lower than the standard model value, as observed in b→s penguin decays. We conclude with the perspectives of the next generation of flavor-physics experiments, the precision they can reach and their phenomenological impact.