燃气流量低频脉动下的火焰结构特征

针对一种可降低天然气高温燃烧过程中NOx生成量的脉动供燃料燃烧技术,研究了一个采用燃气流量脉动燃烧方式的射流扩散火焰。采用纹影和直接摄像手段观察了在燃气流量低频率(10Hz以下)脉动工况下的火焰特征及其变化,分析了火焰长度脉动特征和火焰内部结构的周期发展过程。研究发现:火焰内部结构的周期发展过程包括高速(波峰流量)燃气脉冲冲出、增长、燃气惯性冲出、回吸、低速(波谷流量)和高速燃气脉冲的分离、低速脉冲的增长等阶段。其中低速和高速燃气脉冲的分离是单火焰燃烧不稳定的原因。     

基于根移动方法的LQR控制器设计

阐述一种LQR控制器设计的新方法。根据哈密尔顿系统理论,深入研究了系统特征方程的闭环极点和加权矩阵的关系,给出了希望加权矩阵的确定方法。通过Matlab仿真实验,证明了根据极点的移动范围来确定LQR控制器的方法是可行的。     

A recovery method using recently updated record information in shared-nothing spatial database cluster

A shared-nothing spatial database cluster is system that provides continuous service even if some system failure happens in any node. So,an efficient recovery of system failure is very important. Generally,the existing method recovers the failed node by using both cluster log and local log. This method,however,cause several problems that increase communication cost and size of cluster log. This paper proposes novel recovery method using recently updated record information in shared-nothing spatial database cluster. The proposed technique utilizes update information of records and pointers of actual data. This makes a reduction of log size and communication cost. Consequently,this reduces reccvery time of failed node due to less processing of update operations.     

基于降维的堆积降噪自动编码机的表情识别方法

堆积降噪自动编码机是一种典型的深度学习模型,它能够刻画数据丰富的内在信息,具有较强的特征学习能力。基于主成分分析（principal component analysis,PCA）技术和堆积降噪自动编码机（stacked denoising autoen-coders,SDAE）模型,提出一种新的表情识别算法PCA＋SDAE。该算法对人脸图片进行裁剪及归一化等预处理,采用主成分分析技术对人脸特征进行线性降维,再利用堆积降噪自动编码机逐层进行特征学习并同时实现对人脸表情数据的非线性降维,可以得到更好的、维度更低的表情特征,并据此进行表情分类。对PCA＋SDAE算法的仿真测试实验结果表明,其综合性能比其他的基于深度学习模型的表情识别方法更好,同时与传统的非深度学习表情识别方法相比,它具有更高的表情识别正确率。     

Forecasting Interest Rates and Yield Spreads: The Informational Content of Implied Futures Yields and Best-fitting Forward Rate Models

Forecasts of interest rates for different maturities are essential for forecasts of asset prices. The growth of derivatives markets coupled with the development of complex theories of the term structure of interest rates have provided forecasters with a rich array of variables for predicting interest rates and yield spreads. This paper extends previous work on forecasting future interest rates and yield spreads using market data for T-bills, T-Notes, and Treasury Bond spot and futures contracts. The information conveyed in technical models that use market data is also assessed, using a recent innovation in interest rate modelling, the maximum smoothness approach. Forecasts from this model are compared with predicted yields and yield spreads derived from futures prices as well as with those of the random walk model. The results show some evidence of market segmentation, with more arbitrage evident for nearby maturities. Market participants appear to show a greater degree of consensus on short-term interest rates than on longer-term interest rates. There is some indication that forecasts from the futures markets are marginally better than those provided by those of the maximum-smoothness approach, consistent with the informational advantages of futures markets. Finally, futures and maximum-smoothness market forecasts are shown to outperform those of the random walk model.© 1997 John Wiley & Sons, Ltd.     

Fabrication and characterization of 3D scaffold using 3D plotting system

In this paper, we design and fabricate a 3D scaffold using rapid prototyping (RP) technology for tissue engineering. The scaffold should have a three-dimensional interconnected pore network. We fabricate a polycaprolactone (PCL) scaffold with interconnecting pores and uniform porosity for cell ingrowth using a 3D plotting system. In order to keep the three dimensional shape under mechanical loading while implanted, we design an oscillating nozzle system to increase elastic modulus and yield strength of PCL ...     

飞机草活性物质的提取及对有毒蓝藻的增殖抑制

飞机草(Eupatorium odoratum Linn.)活性物质对有毒蓝藻铜绿微囊藻(Microcystis aeruginosa Kutzing.var.minor.H.W.Liang.,记作:NIES298)和鱼害微囊藻(Microcystis ichthyoblabe Kutz.,记作:TAC95)具有增殖抑制作用.飞机草不同溶剂的浸提液时NIES298和TAC95的抑制效果:蒸馏水浸提比乙醇、丙酮抑制效果好.层析分离活性成分后,发现D3(Rf=0.524)的分离物对两种蓝藻的抑制作用非常明显,74μg/g时即己表现出抑制作用,并且随着飞机草浸提液使用剂量的加大,两种蓝藻的叶绿素a浓度明显低于起始值.     

Implementation of spatial touch system using time-of-flight camera

Recently developed timeofflight principle based depthsensing video camera technologies provide precise perpixel range data in addition to color video. Such cameras will find application in robotics and visionbased human computer interaction scenarios such as games and gesture input systems. Timeofflight principle range cameras are becoming more and more available. They promise to make the 3D reconstruction of scenes easier, avoiding the practical issues resulting from 3D imaging techniques based on triangulation or disparity estimation. A spatial touch system was presented which uses a depthsensing camera to touch spatial objects and details on its implementation, and how this technology will enable new spatial interactions was speculated.     

Transmit Antenna Selection with Power and Rate Allocation for Spatial Multiplexing in Distributed Antenna Systems

Introduction Future mobile and wireless applications will require significantly higher data rates and significantly-reduced costs per transmitted bit as compared to the third generation systems.However,single antenna sys-tems cannot meet the requirements …