旋转导向工具多列块式滑动轴承载荷研究

多列块式径向滑动轴承是推靠式旋转导向工具轴承系统新近采用的一种轴承形式。为了研究近钻头端径向滑动轴承摩擦副的载荷特性,采用Augmented Lagrange摩擦接触非线性算法,考虑旋转导向工具几何非线性效应,利用ANSYS Workbench软件,进行了滑动轴承各列摩擦块的力学分析。对钻头压力为200 kN、翼肋推力分别为10和25 kN的2种载荷工况下摩擦副应力分析结果表明:选用材料满足载荷工况强度要求;轴承内、外圈各列摩擦块的最大应力分布以半周分界呈现2种变化规律,近翼肋和近钻头的2列摩擦块应力水平及分布受外载荷影响较大,近钻头列摩擦副的载荷明显高于其他3列;翼肋推力的增大导致内圈各列摩擦块在2种载荷工况下的最大应力比值达6倍以上,远高于外圈摩擦块,使内、外圈摩擦块的最高应力水平接近相等;轴承内圈近翼肋和近钻头的两列摩擦块在工作中承受较高应力幅的周期性交变载荷,易发生疲劳破坏。研究结果为推靠式旋转导向工具多列块式滑动轴承的设计与合理使用提供了理论支持。

一种有效的3D存储器内建自修复方案

与2D存储器相比,3D存储器能够提供更大的容量、更高的带宽、更低的延迟和功耗,但成品率低。为了解决这个问题,提出一种有效的3D存储器内建自修复方案。将存储阵列的每一行或每一列划分成几个行块或列块,在不同层的行块或列块之间进行故障单元的映射,使不同层同一行或同一列的故障在逻辑上映射到同一层中,从而使一个冗余行或冗余列能够修复更多的故障,大大增加了冗余资源利用率和故障修复率。实验结果表明,与其他修复方案相比,该方案的修复率更高,实现相同修复率所需的冗余资源更少,增加的面积开销几乎可忽略不计。

High Speed VCSEL-Based Parallel Optical Transmission Modules

Design and fabrication of a parallel optical transmitter are reported. The optimized 12 channel parallel optical transmitter,with each channel＇s data rate up to 3Gbit/s,is designed, assembled, and measured. A top-emitting 850nm vertical cavity surface emitting laser（VCSEL） array is adopted as the light source,and the VCSEL chip is directly wire bonded to a 12 channel driver IC. The outputs of the VCSEL array are directly butt coupled into a 12 channel fiber array. Small form factor pluggable （SFP） packaging technology is used in the module to support hot pluggable in application. The performance results of the module are demonstrated. At an operating current of 8mA, an eye diagram at 3Gbit/s is achieved with an optical output of more than 1mW.

Correlation-based subblock partition design for PTS approach

In order to exploit the capability of the peak-to-average power ratio（PAPR）reduction afforded by the partial transmit sequences （PTS）approach in orthogonal frequency division multiplexing（OFDM）systems, subblock partition schemes for the PTS approach are studied. The motivation is to establish the relationship between the subblock partition and the capability of PAPR reduction through the periodic autocorrelation functions （ACFs）of partial transmit sequences and the periodic cross-correlation functions（CCFs）of signal candidates.Let Q represent the variation of the square magnitudes of ACFs.It is found that the lower the Q-value is, the better PAPR performance can be achieved, which is introduced as a design criterion for subblock partition.Based on this criterion, four common partition methods are compared and an efficient partition strategy is proposed. It is shown that structured partition schemes with low computational complexity have a large Q-value, leading to a poor PAPR performance.The new strategy can be regarded as a trade-off between PAPR performance and computational complexity.The simulation results show that the strategy can achieve an optimal performance with a relatively low complexity and, moreover,does not increase the amount of side information.

EmEditor V3．34英文版

简单好用的文本编辑器，支持多种配置，自定义颜色、字体、工具栏、快捷键设置，可以调整行距，避免中文排列过于紧密，具有选择文本列块的功能（按ALT键拖动鼠标)，并允许无限撤消，重做，总之功能多多，使用方便。是替代记事本的最佳编辑器。

30Gbit/s Parallel Optical Receiver Module

A 30Gbit/s receptor module is developed with a CMOS integrated receiver chip（IC） and a GaAs-based 1 × 12 photo detector array of PIN-type. Parallel technology is adopted in this module to realize a high-speed receiver module with medium speed devices. A high-speed printed circuit board（PCB） is designed and produced. The IC chip and the PD array are packaged on the PCB by chip-on-board technology. Flip chip alignment is used for the PD array accurately assembled on the module so that a plug-type optical port is built. Test results show that the module can receive parallel signals at 30Gbit/s. The sensitivity of the module is - 13.6dBm for 10^-13 BER.

An Efficient Adaptive Failure Detection Mechanism for Cloud Platform Based on Volterra Series

Failure detection module is one of important components in fault-tolerant distributed systems,especially cloud platform.However,to achieve fast and accurate detection of failure becomes more and more difficult especially when network and other resources' status keep changing.This study presented an efficient adaptive failure detection mechanism based on volterra series,which can use a small amount of data for predicting.The mechanism uses a volterra filter for time series prediction and a decision tree for decision making.Major contributions are applying volterra filter in cloud failure prediction,and introducing a user factor for different QoS requirements in different modules and levels of IaaS.Detailed implementation is proposed,and an evaluation is performed in Beijing and Guangzhou experiment environment.

Research on Strong Earthquake Tendency on Active Tectonic Block Boundaries in the Chinese Mainland

Previous studies have shown that the active tectonic block boundaries in the Chinese mainland are the main belts and concentration areas of strong earthquakes occurring in the Chinese mainland.It is essential to carry out follow-up analysis of strong earthquake risk of active tectonic block boundaries.In this paper,we carry out the analysis on the tendency of strong earthquakes along each active tectonic block boundary from three aspects respectively,including the evolutionary characteristics of the Load/Unload Response Ratio time series,the probability method based on the log-normal distribution function,and variation of b value.The estimation of strong earthquake criticality on each active tectonic block boundary is done based on the evolutionary characteristics of the Load/Unload Response Ratio time series,the cumulative probability and conditional probability,and the decrease of the b value.Finally,according to the results of analyses on the above three aspects,the potential strong earthquake areas in the forthcoming 5 years in the Chinese mainland are discussed.

Design of Parallel Electrical Resistance Tomography System for Measuring Multiphase Flow

ERT(electrical resistance tomography) is effective method for visualization of multiphase flows,offering some advantages of rapid response and low cost,so as to explore the transient hydrodynamics.Aiming at this target,a fully programmable and reconfigurable FPGA(field programmable gate array)-based Compact PCI(peripheral component interconnect) bus linked sixteen-channel ERT system has been presented.The data acquisition system is carefully designed with function modules of signal generator module;Compact PCI transmission module and data processing module(including data sampling,filtering and demodulating).The processing module incorporates a powerful FPGA with Compact PCI bus for communication,and the measurement process management is conducted in FPGA.Image reconstruction algorithms with different speed and accuracy are also coded for this system.The system has been demonstrated in real time(1400 frames per second for 50 kHz excitation) with signal-noise-ratio above 62 dB and repeatability error below 0.7%.Static experiments have been conducted and the images manifested good resolution relative to the actual object distribution.The parallel ERT system has provided alternative experimental platform for the multiphase flow measurements by the dynamic experiments in terms of concentration and velocity.

Research on General Permutation Encryption Module Based on Chaos Theory

Replacement and substitution encryption are two basic types of encryption historically. The classical encryption algorithm has been compromised now, but they still can play special role for modem cryptnlogy. For example, in digital image encryption system, substitution can disrupt the original order of the images and eliminate the correlation of image information which not only can realize security of images, but also can resist intentional attack and destruction of clipping and noise. And transposition transformation is introduced into the design of block ciphers. The substitution has the feature of high efficiency and resistance, which makes it meet the specific requirements of encryption. So substitution cypher can be applied to modern encryption system.

Hypercube and Tetrahedron Algebra

Let D be an integer at least 3 and let H(D, 2) denote the hypercube. It is known that H(D, 2) is a Q-polynomial distance-regular graph with diameter D, and its eigenvalue sequence and its dual eigenvalue sequence are all {D-2i}D i=0. Suppose that denotes the tetrahedron algebra. In this paper, the authors display an action of ■ on the standard module V of H(D, 2). To describe this action, the authors define six matrices in Mat X(C), called A, A*, B, B*, K, K*.Moreover, for each matrix above, the authors compute the transpose and then compute the transpose of each generator of ■ on V.

A Network Partition Algorithm for Mining Gene Functional Modules of Colon Cancer from DNA Microarray Data

Computational analysis is essential for transforming the masses of microarray datainto a mechanistic understanding of cancer. Here we present a method for findinggene functional modules of cancer from microarray data and have applied it tocolon cancer. First, a colon cancer gene network and a normal colon tissue genenetwork were constructed using correlations between the genes. Then the modulesthat tended to have a homogeneous functional composition were identified by split-ting up the network. Analysis of both networks revealed that they are scale-free.Comparison of the gene functional modules for colon cancer and normal tissuesshowed that the modules’ functions changed with their structures.