Study on limited-flux coefficient to achieve spare transportation of heat-supply network

Limited-heating is one of the heating statuses which can meet the reliability requirement of those uninterrupted heat-users under the accidental status of heat-supply network.It requires the network to be provided with both ability of spare-structure and spare-transportation,and the later one is depended on the limited-flux coefficient.This paper investigates the relationship between the limited-flux coefficient and limited-heating coefficient of indirect connection system.The optimal value of the limited-flux coefficient is presented as well.     

分层分段直眼掏槽在石灰岩井筒爆破中的应用研究

主要介绍了复式三角形分层分段直眼掏槽、复式正方形分层分段直眼掏槽以及孔内微差分段直眼掏槽在石灰岩井简爆破中的对比试验情况。结果表明：复式正方形分层分段掏槽在试验井筒中有最佳的爆破效果，并应用现有岩石动力学的成果分析了这一试验结果的原因。此外，试验还表明最佳的炮孔深度接近于井筒的半径。     

低Fr数消能规律研究

通过试验研究找出了低佛氏数水跃消能与一般水跃消能规律的本质区别，得出了低佛氏数水跃在跃后段随着Fr数的减小而出现的水面波动能、断面流速分布、跃后段长度、底流速等水力要素的变化特点，分析了低Fr数水跃消能的一些工程措施。     

Numerical investigation of thermocapillary migration of the drop for large Marangoni numbers

An axisymmetric model is adopted to simulate the problem of unsteady drop thermocapillary motion for large Marangoni numbers. Front tracking methods are used in the investigation. It is found that the non-dimensional drop migration velocity will decrease with increasing Marangoni number. This agrees well with the experimental results obtained from the 4th Shen-Zhou space ship. In the meanwhile, this is also the first time for numerical simulations to verify the experimental phenomenon under large Marangoni numbers. Recommended by Prof. WANG ZhanGuo, Member of Editorial Committee of Science in China, Series E: Technological Sciences Supported by Chinese Academy of Sciencer Innovation Program and the National Natural Science Foundation of China (Grant Nos. G10502054, G10432060)     

一种基于RTP减少包丢失的控制算法及其在VoIP中的应用

本文首先考虑丢包率的控制方案，然后讨论VoIP网关对丢包率的监测，最后在简单带宽调整算法的基础上提出一种改进的控制算法——传输速率自适应调整算法，并将算法运用到VoIP系统中，提出一种自适应变速率语音编码器，来控制语音包的丢失。     

Composition and hardness of mullite coatings formed with direct current power supply on LY12 aluminum alloy surface

The surface modification of aluminum and its alloys using plasma technology is increasingly being investigated, Thick ceramic coatings with high hardness on aluminum alloys can be prepared successfully using a micro-plasma oxidation （MPO） technique. In this work, the composition, microstructure and elemental distribution of ceramic coatings formed by MPO on LY 12 almnlnum alloy and its hardness are investigated using XRD, EPMA and microhardness instruments. The results show that the ceramic coatings consist of mullite,γ-Al2O3 and a lot of amorphous matter. The content of silicon in the coatings increases from interface to the coatings, however, the content of aluminum decreases along this direction. The maximum hardness of ceramic coatings is up to 9.2 GPa.     

An Effective Method to Reduce Sensibility to CFO in OFDM

For orthogonal frequency-division multiplexing (OFDM) communication systems, the carrier frequency offset (CFO) in mobile radio channels distort the orthogonality between subcarriers resulting in intercarrier interference (ICI). This paper studies an efficient scheme termed all phase method to combat ICI. The method is implemented by introducing all phase concept into standard OFDM system. By numerical calculations, ICI coefficients with all phase method are much smaller than that of standard OFDM. Simultaneously, in the present of CFO, simulation results exhibit the proposed method makes more remarkable improvement in BER performance. Therefore, all phase method is effective to reduce sensibility to CFO.     

单端有源箝位DC—DC变换器

单端正激式及反激式变换器的性能，因采用了有源箝位／恢复技术而大大增强。其优点是效率高、对外干扰小、器件应力小。本文介绍了两种有源箝位电路拓扑，并对电路工作状态进行了分析，对磁化电流和负载电流之间的关系进行了推导。最后，对这种有源箝位的DCDC变换器的优点进行了归纳。     

频率特性有间断点的滤波器的全相位设计

本文提出了频率特性有间断点的滤波器伞相位设计方法，给出全相位数字滤波器与原FIR滤波器的结构，推导出了全相位数字滤波器的内插函数，并用实验证明全相位陷波器具有良好的陷波频率特性。