A numerical study of rock burst development and strain energy release

We consider rock burst to be a dynamic disaster similar to earthquakes, rapid land sliding, or coal mine gas dynamic disasters. Multi-scale mechanical principles imply the same mechanism of damage evolution proceeds the catastrophe. Damage may occur at various scales from a meso-scopic scale to a macroscopic, or engineering scale. Rock burst is a catastrophe at the scale of the engineering structure, such as a tunnel cross section or the work face of a long wall mine. It results from dynamic fracture of the structure where microscopic damage nucleates, expands, and finally propagates into a macroscopic sized fracture band. Rock burst must, therefore, undergo a relatively long development, or gestation, time before its final appearance. In this paper, a study of rock burst within a deeply buried tunnel by numerical methods is described. The results show that during rock burst gestation the distributed microscopic damage in the rock surrounding the tunnel localizes, intersects, and then evolves into a set of concentrated “V” shaped damage bands. These concentrated damage bands propagate in the direction of maximum shear as shearing slide bands take shape. Rock burst happens within the wedge separated by the shear bands from the native tunnel rock. An analysis of the wedge fracture shows that the unloading effects result in rock burst and rapid release of the strain energy. The implications for rock burst prediction in tunnels are that: (1) rock burst develops in the upper arch corners of in the tunnel cross section prior to developing in other zones, so good attention must be paid there; (2) all monitoring, prevention, and treatment of rock burst should be done during the gestation phase; (3) the shear bands contain abundant information concerning the physics and mechanics of the process and they are the foundation of physical and mechanical monitoring of acoustic emission, micro seismic events, stress, and the like. Thus a special study of the shearing mechanism is required.     

证券广播、信息处理系统的设计与实现

本文提出一种证券广播、信息处理系统，能实时的完成电脑证券系统的所有功能又无需上网。使用不同的接口．可应用于电脑系统和电视系统。本文主要从两个方面论述了该系统的原理，以W77E58为主芯片的证券信息广播服务器系统和以DALLS80C320为主要芯片的证券信息处理（接收、分析、交易）系统，并在此基础上，详细介绍了实现证券信息广播和接收、分析、交易的方法和原理。     

红外图像目标瞄准点测量和基于自适应Kalman滤波的瞄准点跟踪

前视红外图像(FLIR)包含有关目标形状的丰富信息,可据以识别目标的背景干扰,从而增强抗干扰能力,且可根据目标要害部的亮度特点及预定范围,确定并进而跟踪瞄准点,本文提出目标瞄准点的序贯相关测量与Kalman滤波相结合的跟踪方法,在用110帧红外序列图像目标瞄准点跟踪仿真研究中,获得令人满意的结果,本文给出仿真误差方差、误差曲线和代表性的跟踪照片。     

Computing aware scheduling in mobile edge computing system

Mobile edge computing (MEC) is an emerging technology recognized as an effective solution to guarantee the Quality of Service for computation-intensive and latency-critical traffics. In MEC system, the mobile computing, network control and storage functions are deployed by the servers at the network edges (e.g., base station and access points). One of the key issue in designing the MEC system is how to allocate finite computational resources to multi-users. In contrast with previous works, in this paper we solve this issue by combining the real-time traffic classification and CPU scheduling. Specifically, a support vector machine based multi-class classifier is adopted, the parameter tunning and cross-validation are designed in the first place. Since the traffic of same class has similar delay budget and characteristics (e.g. inter-arrival time, packet length), the CPU scheduler could efficiently scheduling the traffic based on the classification results. In the second place, with the consideration of both traffic delay budget and signal baseband processing cost, a preemptive earliest deadline first (EDF) algorithm is deployed for the CPU scheduling. Furthermore, an admission control algorithm that could get rid off the domino effect of the EDF is also given. The simulation results show that, by our proposed scheduling algorithm, the classification accuracy for specific traffic class could be over 82 percent, meanwhile the throughput is much higher than the existing scheduling algorithms.

     

铁电存储器FM31256在多用户多费率电能表中的应用

FM31256为14脚SOIC小封装,是一种具有12C总线的铁电存储器。本芯片在单个芯片中集成了两个不同的逻辑单元,即256k位（32k字节）铁电存储器单元和实时时钟（RTC）单元,此外还包括非易失性事件计数器、系统复位控制、看门狗计数器、可锁存的64位串行数据密码和用在早期电源失效或其他目的的通用比较器等。     

模糊聚类方法在医学病理图像分类中的应用

图象分割和对象提取是从图象处理到图象分析的关键步骤。本文将经典的模糊C-均值聚类算法和模糊测度和模糊积分结合起来,并将这两种算法应用于医学病理图象的分割。经典的模糊C-均值聚类算法采用欧式距离计算像素之间的相似度,本文中采用模糊测度和模糊积分计算像素之间的相似度,基于模糊测度和模糊积分的特点,这种计算方法可以提高计算的准确度。最后对两种算法的处理结果进行了比较,结果表明改进的模糊C-均值算法对医学病理图像的分割效果比原算法有所改进。     

利用现代分析仪器结合化学计量学软件开设化学动力学实验

开设了“紫外光谱法在线测量连串反应动力学过程”的综合性实验。使用DAD紫外光谱仪在线测量邻苯二甲酸二乙酯在碱性条件下水解的连串反应,该反应体系中各组分的光谱重叠严重。利用化学计量学中的目标试验-数值遗传算法(TT—NGA)优化搜索动力学参数,采用Delphi7．0编写了处理实验数据的辅助教学软件TTNGA．exe,在Windows系统下该软件可方便使用。用该软件处理测得的动力学-光谱矩阵可以快速方便地获得各组分的纯光谱,动力学曲线和反应级数及速率常数。该实验的开设,培养了学生使用现代分析仪器并利用计算机技术和数学知识解决化学问题的能力,取得了良好的教学效果。     

利用ITTFA解析磺胺甲基异噁唑的酸度分布-光谱矩阵数据

根据药物磺胺甲基异(口恶)唑水溶液随pH 值变化的分布曲线并结合其吸收光谱构成二维波谱矩阵,在无需数学模型的前提下,利用ITTFA 方法对其进行解析,获得该药物各型体的纯光谱和酸度分布曲线。基于各型体等吸收点原理构造初始迭代矢量,确保ITTFA 法能快速收敛于正确的唯一解。ITTFA 法解析出的相对分布曲线可根据质量平衡原理用最小二乘回归进行标准化,从而获得与实际情况一致的真实分布曲线,并进一步基于非线性最小二乘-参数优化法求解该药物的两步酸离解常数。     

Influences of friction drag on spontaneous condensation in water vapor supersonic flows

A mathematical model was developed to investigate the water vapor spontaneous condensation under supersonic flow conditions. A numerical simulation was performed for the water vapor condensable supersonic flows through Laval nozzles under different flow friction conditions. The comparison between numerical and experimental results shows that the model is accurate enough to investigate the supersonic spontaneous condensation flow of water vapor inside Laval nozzles. The influences of flow friction drag on supersonic spontaneous condensation flow of water vapor inside Laval nozzles were investigated. It was found that the flow friction has a direct effect on the spontaneous condensation process and therefore it is important for an accurate friction prediction in designing this kind of Laval nozzles. Supported by the National Natural Science Foundation of China (Grant No. 50676002), the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20040005008) and the Beijing Best Innovation Person Selecting Project (2006)     

Fractal model for simulation of frost formation and growth

A planar fractal model for simulation of frost formation and growth was proposed based on diffusion limited aggregation(DLA)model and the computational simulation was carried out in this paper.By changing the times of program running circulation and the ratio of random particles generated,the simulation figures were gained under different conditions.A microscope is used to observe the shape and structure of frost layer and a digital camera with high resolution is used to record the pattern of frost layer at...