Frequency-dependent losses on high-performance interconnections

This paper compares the major classes of chip-to-chip and on-chips interconnections used in high-performance computers and communication systems and reviews their electrical characteristics. Measurement results of dielectric loss are shown and the attenuation is compared for printed-circuit-board, glass-ceramic, thin-film, and on-chip wiring. Simulation results are shown with representative driver and receiver circuits, guidelines are given for when losses are significant, and predictions are made for the sustainable bandwidths on useful wiring lengths     

建立大坝安全网络管理系统

为进一步完善和提高我国水电厂大坝安全管理水平 ,简述了建立大坝安全网络管理系统的必要性和可行性 ,提出了大坝安全网络管理中心的工作职能以及系统建立的方法和步骤     

闪急沸腾喷雾场粒度分布特性的研究

用激光全息术测量了闪急沸腾喷雾场的粒度分布，并与常温雾场粒度分布进行了比较。结果表明，闪急沸腾喷雾场的粒度分布具有喷雾粒子直径小，喷注的轴向径向粒子分布均匀等特点。     

Optimal PN sequence design for quasisynchronous CDMA communicationsystems

Direct sequence (DS) code-division multiple-access (CDMA) is a modulation and multiple access technique currently being implemented in digital cellular mobile radio communication systems. The conventional quasisynchronous (QS) DS-CDMA communication system is generalized, and the problem of optimal spreading pseudonoise (PN) sequence design for new QS DS-CDMA communication systems is formulated. The classes of optimal PN sequences which have good pseudo-randomness and very small cross-correlation values for some range of offsets are designed by using a matrix-based approach. In contrast to the case of the other sequences, the optimal PN sequences produce small multiple-access interference (MAI) which is not affected by the number of users if there are sufficiently large number of users in the link. The new results are compared with the commonly used PN sequences to prove the superiority of our designed sequences, and the system performance of the QS-CDMA systems using different PN sequences are also evaluated     

水下通信中的异常声压监控网络系统设计

传统水下通信声压异常监控网络存在无法自主完成节点的投放和回收,存储监控盲区并且无法进行动态组网,不能对异常声压进行准确的监控等较大的缺陷;为此,设计并实现了一种新的水下异常声压监控系统,系统中的通信协议基于节点间的深度信息完成数据的转发,给出了系统中监控器、CC2430处理器、终端节点以及协调器节点的硬件设计原理并给出了系统采集数据的软件流程;系统中实现了对链路层的AODV路由协议进行改进,增强系统对异常声压的监控性能;测试结果说明,该系统获取的声压监测星座图明显优于传统系统,在不同的干扰类型下,发射信号使用PSK调制,载波中心频率是10kHz,采样率是50kHz,码率是2 000bit/s;实验结果表明:该种系统具有较低异常声压信号监控误差率,可对异常声压信道的传输特性进行较好的校正和补偿,具有较强稳定性。     

Phase composition of arc-melted alloys in the ternary systemCe–Al–Cu (Cu-poor portion)

The phase composition of arc-melted alloys in the ternary system Ce–Al–Cu (Cu-poor portion) in the as-cast state were investigated by X-ray powder diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM) techniques. The investigated composition region consists of 16 single-phase, 32 two-phase and 17 three-phase regions. In as-cast state, the solubilities of the solid solution phases were determined. The CeAlCu compound decomposes into three phases: Ce(Al_0.92Cu_0.08)₂, Ce(Al_0.4Cu_0.6)₅ and Ce₂AlCu₂ in as-cast state. Based on the constructed phase composition regions of the investigated alloys in the as-cast state, it reveals that the reported composition region of the bulk glass alloys in the Ce–Al–Cu system falls in the three-phase regions 15–17 with α-Ce₃Al as the common phase which is supposed to play an important role in the glass-forming process.     

准谐振软开关控制器IRIS4015的设计及应用

IRIS4015是一款专用准谐振软开关控制器，该芯片功能齐全，使用外围元件少，并具有完善的保护电路。文中详细介绍了该芯片的特点、功能，给出了其典型应用电路。     

Propriétés spectrales d’un laser semiconducteur soumis à une rétroaction optique externe

The rate equations of a semiconductor laser with external optical feedback are solved numerically. The method is applied to the case of simple optical feedback and to that of a high finesse external resonator. The spectral linewidth reduction, the damping of the relaxation oscillations and the influence of the resonant frequencies of the external resonator are discussed and compared for these two configurations.     

Effective Hybrid/Mixed Finite Elements for Folded-Plate Structures

A new formulation in which the assumed stress field is divided into membrane and bending stress fields is developed. A family of effective shell elements of hybrid/mixed finite element method that accounts for transverse shear deformations is proposed based on a modified Hellinger–Reissner variational principle. In this paper, the present shell elements possess different three-field assumptions, which are described by compatible displacement, incompatible displacement, and stress fields. Several benchmark problems are conducted to test both the accuracy and reliability of the proposed shell elements. Numerical analyses show that the present shell elements pass all the patch tests, do not contain any spurious zero energy modes, and have no lock phenomena even for very thin plate and shell. Further insight into the performance of the present shell elements is gained to demonstrate the high accuracy of the elements by several folded-plate structure problems. The numerical results demonstrate the validity, reliability, and applicability of the present elements. The present elements are valid for thick as well as thin shell structures.