辽河油田超稠油三元复合吞吐影响因素研究

针对辽河油田曙一区超稠油井吞吐轮次高、吞吐效果逐渐变差的特点,提出了超稠油三元复合吞吐采油工艺技术。通过11管人造岩心物理模拟驱替实验,开展了超稠油三元复合吞吐影响因素研究。实验结果表明：水蒸汽注入量、CO2注入量及表面活性剂使用质量分数对工艺效果均有影响。其研究结果对优化超稠油三元复合吞吐施工工艺及施工参数有重要的指导意义。     

Carreau两段黏度模型应用于苯乙烯-丁二烯-苯乙烯嵌段共聚物/高岭土改性沥青的研究

采用流变学方法研究了苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)/高岭土改性沥青的流变性能,并用Carreau两段黏度模型对流变性能进行了模拟.结果表明,在实验温度范围内,基质沥青为简单牛顿流体,SBS改性沥青为非牛顿流体;SBS改性沥青存在着2个剪切变稀区域,且星形SBS改性沥青较线型SBS改性沥青的2个剪切变稀区域更为明显,随着SBS用量的增加,剪切变稀越明显.在低频区,Carreau两段黏度模型模拟曲线与实验曲线重合;随着SBS含量的增加或加入高岭土,第一时间参数值增大,高岭土与SBS的预先共混促使SBS在改性沥青中的表观份数有所增加.     

ScienceWord+PagePlayer模式电子教案设计与实现——《多面体和棱柱》课题教案制作

随着教学办公自动化的发展,针对"Word+PowerPoint模式"电子教案模式中的一些不足,应用ScienceWord和PagePlayer设计制作的电子教案不仅能够方便制作出各种几何图形,还能快速制作出各种教学需要的特效文字,实现更简便高效的电子教案制作。     

Evaluating MODIS data for mapping wildlife habitat distribution

Habitat distribution models have a long history in ecological research. With the development of geospatial information technology, including remote sensing, these models are now applied to an ever-increasing number of species, particularly those located in areas in which it is logistically difficult to collect habitat data in the field. Many habitat studies have used data acquired by multi-spectral sensor systems such as the Landsat Thematic Mapper (TM), due mostly to their availability and relatively high spatial resolution (30 m/pixel). The use of data collected by other sensor systems with lower spatial resolutions but high frequency of acquisitions has largely been neglected, due to the perception that such low spatial resolution data are too coarse for habitat mapping. In this study we compare two models using data from different satellite sensor systems for mapping the spatial distribution of giant panda habitat in Wolong Nature Reserve, China. The first one is a four-category scheme model based on combining forest cover (derived from a digital land cover classification of Landsat TM imagery acquired in June, 2001) with information on elevation and slope (derived from a digital elevation model obtained from topographic maps of the study area). The second model is based on the Ecological Niche Factor Analysis (ENFA) of a time series of weekly composites of WDRVI (Wide Dynamic Range Vegetation Index) images derived from MODIS (Moderate Resolution Imaging Spectroradiometer – 250 m/pixel) for 2001. A series of field plots was established in the reserve during the summer–autumn months of 2001–2003. The locations of the plots with panda feces were used to calibrate the ENFA model and to validate the results of both models. Results showed that the model using the seasonal variability of MODIS-WDRVI had a similar prediction success to that using Landsat TM and digital elevation model data, albeit having a coarser spatial resolution. This suggests that the phenological characterization of the land surface provides an appropriate environmental predictor for giant panda habitat mapping. Therefore, the information contained in remotely sensed data acquired with low spatial resolution but high frequency of acquisitions has considerable potential for mapping the habitat distribution of wildlife species.     

无线局域网的构建

随着无线网络技术的日趋成熟,无线网络的应用越来越广泛,详细地介绍了无线局域网的几种标准,无线网络构建的六种方案,以及在无线网络中常见的几种安全问题的解决方案。     

气相反应产物中固相沉积始现的反应温度点计算

许多气相反应不希望出现固相产品,如燃烧过程不希望有积碳。本文研究气相反应产物在什么条件下出现固体。根据Gibbs自由能最小等热力学原理,提出1种将化学反应平衡和固体饱和蒸汽压数据相结合,求气相反应产物中固相沉积始现的反应温度点的计算方法。举出氯硅烷氢化等7个体系的算例。结果表明:本法与传统的Gibbs自由能最小法结果相同;在同样的进料条件下,每个体系均存在1个固相沉积的温度范围。本文确定的这种温度范围对探讨气体反应的固相沉积现象具有很好的指导意义,所选算例得出:SiHCl_3氢化等4个体系有2个沉积温度点(TD_1,TD_2),即这些平衡体系有2个沉积的温度转折点,如果不希望有沉积,就必须使进料温度小于TD_1或者大于TD_2;而CH_4部分氧化等3个体系只有1个沉积温度点TD,此类平衡体系如果不希望有沉积,进料温度就应大于TD。     

WGZ75/39-6 型煤粉炉冷态试验分析

介绍了湘潭钢铁公司热电厂６＃锅炉进行冷态试验的情况,同时说明了煤粉锅炉冷态试验的内容、方法．详细分析了试验中所出现的问题和结果,探讨了影响炉内空气动力场的有关因素,就如何组织良好的炉内空气动力场结构,保证燃料喷入炉膛后迅速着火和燃烬,防止炉内结渣,使该锅炉在最佳运行工况下运行,提高锅炉的效率,提供了改进措施．     

集成光学用单模磁光波导薄膜

采用双层（ＢｉＡｌ）ＹＩＧ膜结构来制作单模磁光波导。通过改变外延生长工艺来调节两层薄膜的折射率，可在一定波导的厚度范围内实现单模传输。Ｘ射线衍射测量表明薄膜质量良好，且易磁化方向平行膜面，最后利用棱镜耦合，观察了波导中的暗ｍ线。     

OFDM无线通信中高峰均比及其抑制算法研究

凭借很强的抗符号间干扰(ISI)和抗衰落能力,采用正交频分信道的OFDM技术的无线通信越来越受到人们的重视。但是作为一种多载波调制方式,OFDM技术同样存在着高峰均比(PAPR)的问题,高的PAPR会导致信号畸变,造成子信道间的相互干扰,从而影响OFDM的性能。针对此,重点介绍了OFDM系统中的PAPR比问题的概念,并对降低PAPR的主要算法进行了论述。     

On the Sum Rate Capacity of MIMO Broadcast Channels in Cognitive Radio Networks with Interference Power Constraints

This paper investigates the sum rate capacity of MIMO broadcast channels (MIMO-BCs) in cognitive radio networks. A suboptimal user-selection algorithm is proposed to achieve a large sum rate capacity with reduced complexity. This algorithm consists of two steps. First, zero-forcing beamforming is utilized as a downlink precoding technique that precancels inter-user interference. Second, singular value decomposition is applied to the channel matrices of all the secondary users and only consider the singular vectors corresponding to the maximum singular values. The proposed user-selection algorithm chooses singular vectors which are nearly orthogonal to each other and nearly orthogonal to the vector of primary users. With this algorithm, the sum rate capacity of MIMO-BCs in CR networks with interference power constraints and transmit power constraints is derived. We formulate the sum rate capacity as a multi-constraint optimization problem and develop an algorithm to solve the problem in its equivalent form. Finally, numerical simulations are conducted to corroborate our theoretical results in flat Rayleigh fading environments. It is shown that the proposed algorithms are capable of achieving a large sum rate capacity with a very low complexity.