地下柴油发电站机房的通风与降温设计

介绍了柴油发电机组的几种换热方式与发热量的构成。强调了采用通风降温时,换热器的热风不能排入机房,应直接排入排风道,再由耐高温风机排至室外。通过实例说明了这种降温方式最小进排风量的计算方法。介绍了目前工程中存在的几个共性问题,并提出了解决方法。     

水文学法在水土流失问题研究中的应用

本文根据4年多的研究成果,分析了用水文学法研究水土流失问题的可行性,介绍了水文学法研究水土流失的方法步骤,并与经验公式法研究成果进行对比,以供参考.     

聚合物与水气交替联驱提高采收率试验研究

采用三种不同沉积韵律平面模型试验研究水驱后聚合物与水气交替联驱提高原油采收率的驱替特征。结果表明,聚合物与水气交替联驱对正韵律油藏提高采收率效果很好;对反韵律油藏和复合韵律油藏也有不同程度提高采收率效果。通过分析两种不同韵律砂岩油藏水气交替提高采收率矿场试验成功实例,认为聚合物与水气交替联驱法可综合发挥两种方法的优势,在类似油藏中比单一方法有更好的提高采收率效果。     

Temperature- and dc bias field- dependent piezoelectric effect of soft and hard lead zirconate titanate ceramics

The dc bias field-dependent piezoelectric coefficient d ₃₃ of lead zirconate titanate ceramics (PZT5, PZT8 and P5H) were determined by a quasi-static method. It was found that piezoelectric coefficient d ₃₃ was almost independent of positive dc bias field for PZT8 and PZT5 ceramics, while for P5H ceramic an obvious decrease of coefficient d ₃₃ was observed under positive dc bias field. On the other hand, the temperature-dependent piezoelectric response for PZT ceramics were investigated by both quasi-static and resonance methods. The piezoelectric coefficient d ₃₃ was found to increase with increasing temperature for both PZT5 and PZT8 ceramics. For P5H ceramics, coefficient d ₃₃ showed a first decreasing and then increasing tendency with respect to temperature. These results were discussed in terms of intrinsic and extrinsic contributions to piezoelectric response.     

广东电网光传输色散受限系统研究

随着电网业务的不断拓展,电力通信传输系统的传输速率越来越高、距离越来越长。如何在高速率长距离的情况下,保证传输信号的质量已经成为当务之急。文章介绍了高速率、长距离情况下的光传输色散受限系统,并结合广东电网的实际线路,对色散补偿技术进行实例分析,解决了现网中出现的一些线路故障,为今后电力专网工程建设和维护提供技术指导。     

"电机与拖动"课程教学改革的探索

"电机与拖动"是自动化专业的一门专业基础课,在专业课学习过程中起着承上启下的作用,其教学质量好坏直接影响到许多后续课程的学习.从提高学生的主动性,调整教学内容,创新教学方法,丰富教学手段等方面介绍了课程教学改革的思路和具体措施,并在教学实践中进行了尝试,取得了较好的效果.     

Spectral efficiency of distributed antenna system with random antenna layout

The downlink capacity potential of a distributed antenna system (DAS) with random antenna layout is investigated. A low complexity sub-optimal power allocation scheme among transmit antennas is proposed. Simulation results show that with the same antenna density DAS outperforms a co-located antenna system (CAS) in terms of average and outage spectral efficiency.     

Wireless capsule endoscopy video segmentation using an unsupervised learning approach based on probabilistic latent semantic analysis with scale invariant features

Since wireless capsule endoscopy (WCE) is a novel technology for recording the videos of the digestive tract of a patient, the problem of segmenting the WCE video of the digestive tract into subvideos corresponding to the entrance, stomach, small intestine, and large intestine regions is not well addressed in the literature. A selected few papers addressing this problem follow supervised leaning approaches that presume availability of a large database of correctly labeled training samples. Considering the difficulties in procuring sizable WCE training data sets needed for achieving high classification accuracy, we introduce in this paper an unsupervised learning approach that employs Scale Invariant Feature Transform (SIFT) for extraction of local image features and the probabilistic latent semantic analysis (pLSA) model used in the linguistic content analysis for data clustering. Results of experimentation indicate that this method compares well in classification accuracy with the state-of-the-art supervised classification approaches to WCE video segmentation.