电泵井振动监测及传输系统设计

潜油电泵机组是具有超细长转轴的复杂旋转机械,有复杂的生产及安装工艺,且采用了多级离心泵,在生产过程中会产生强大的振动源,测量并分析机组振动状况,是评估潜油电泵机组的运行状况、提高可靠性的重要手段。本文采用MMA3201振动加速度计监测振动状况,并采用4 mA²0 mA电流环将信号传输到井上MCU进行分析处理,根据监测和处理结果,适时提泵检修,采取合理的减振措施,延长潜油电泵的使用寿命。     

Laplacian group sparse modeling of human actions

Recently, many local-feature based methods have been proposed for feature learning to obtain a better high-level representation of human behavior. Most of the previous research ignores the structural information existing among local features in the same video sequences, while it is an important clue to distinguish ambiguous actions. To address this issue, we propose a Laplacian group sparse coding for human behavior representation. Unlike traditional methods such as sparse coding, our approach prefers to encode a group of relevant features simultaneously and meanwhile allow as less atoms as possible to participate in the approximation so that video-level sparsity is guaranteed. By incorporating Laplacian regularization the method is capable to ensure the similar approximation of closely related local features and the structural information is successfully preserved. Thus, a compact but discriminative human behavior representation is achieved. Besides, the objective of our model is solved with a closed-form solution, which reduces the computational cost significantly. Promising results on several popular benchmark datasets prove the efficiency and effectiveness of our approach.     

Detecting changes of the Yellow River Estuary via SAR images based on a local fit-search model and kernel-induced graph cuts

The Yellow River Estuary area of China is under great pressure from both human intervention and natural processes. For analysis of the changes in this area, this article presents a novel change-detection method based on a local fit-search model and kernel-induced graph cuts in multitemporal synthetic aperture radar images. Change detection involves assigning a label to every pixel. This task is naturally formulated in terms of energy minimization, which can be effectively solved by graph cuts. The difference image is transformed implicitly by a kernel function so that an alternative to complex modelling of the original data makes the piecewise constant model become applicable for graph cuts formulation. An issue is that graph cuts are sensitive to the initial estimate. The local fit-search model is proposed to approximate to the local histogram while selecting an optimal threshold for the initial labelling, which leads to an effective constraint for graph cuts and computational benefits as well. Visual and quantitative analyses obtained on the Yellow River Estuary data set confirm the effectiveness of the proposed method and that it outperforms the other state-of-the-art methods of change detection.     

基于逐次散射法的海洋-大气矢量辐射传输模式

首先推导了粗糙洋面双向偏振反射模型pBRDF(Bidirectional Polarized Reflectance Distribution Function),并将其与SOSVRT(Successive Order of Scattering Radiative Transfer)矢量辐射传输模式耦合,建立了海洋-大气耦合的矢量辐射传输模式,并对该耦合模式的模拟结果与前人模拟结果进行对比,验证了该耦合模式的可靠性与有效性。不同大气和洋面状态、不同高度的主平面内辐射强度和偏振度的模拟结果表明:pBRDF模型可以很好地模拟不同风速下洋面的偏振反射分布特征;洋面在特定角度具有很高的偏振度,并对大气顶的偏振辐射有很大影响。因此,该耦合模式可以更准确地处理辐射光谱在海洋-大气两种介质间的传输问题,对矢量辐射传输、大气遥感问题的研究有重要意义。     

浅谈多媒体教学以信息管理中心为例

高职教育的特点就是以适应社会需要为目标、以培养技术应用能力为主线设计学生的知识、能力、素质结构和培养方案,毕业生应具有基础理论知识适度、技术应用能力强、知识面较宽、素质高等特点.以“应用”为主旨来构建课程和教学内容体系.     

乙烯二聚制高纯丁烯－1技术经济评价

本文对生产高纯度丁烯－１的Ａｌｐｈａｂｎｔｏｌ工艺进行了技术经济评价，认为该工艺条件简单、反应条件温和，而且投资少，所以很适合事在发展中国家应用。     

A low‐profile antenna with circularly polarized reconfigurable and omnidirectional radiation patterns

A low profile circularly polarized (CP) antenna with reconfigurable polarization is designed and presented, which can radiate omnidirectional patterns that can be switched between left‐hand circularly polarized (LHCP) and right‐hand circularly polarized (RHCP). A pair of arc‐shaped complementary dipoles is acted as reconfigurable elements by bridging four pin diodes at the dipole arced arms. A meander phase shift line is employed to connected the arc dipole arms and plate cavity to adjust the phase relationship of two sources. The proposed antenna exhibits the omnidirectional radiation pattern by combining six identical elements placed in a circular array configuration. 24 p‐i‐n diodes are exploited to six elements, by manipulating the dc bias voltage across the diodes, the polarization state of the antenna can be switched. The patterns of the antenna are similar to that of a dipole, but its size is only about Φ0.87 × 0.029λ₀ at 5.8 GHz. The overlapped bandwidth of measured 3‐dB axial ratio (AR) and 10‐dB return loss is 5.724‐5.87 and 5.738‐5.91 GHz for two polarization states, which are right on the target of ISM band. It can be well adapted to medical diagnosis systems.     

基于MEMS电容式加速度计的闭环读出电路设计

设计了面向圆片级封装的一种闭环加速度计读出电路.在基于电容式微加速度计结构的读出电路设计中考虑了寄生电容对整个系统的影响.用MATLAB SIMULINK对所设计的读出电路进行了建模仿真.在仿真过程中分析了噪声、圆片级封装与普通封装的寄生参数及实际工艺中流水结构的不对称性的影响并进行了比较.结果表明,所设计传感器及读出电路的非线性误差在量程±20 gn范围内小于0.5％;圆片级封装的稳定时间在2 ms,小于普通封装的稳定时间;基于圆片级封装的对称性梳齿结构的输出电压灵敏度为328 mV/gn.     

冶炼不锈钢泡沫渣的实验研究

从理论上阐述冶炼不锈钢时熔渣的发泡机理。并根据上海三钢公司的情况，在2500Hz的中频感应炉上时熔渣进行发泡高度的实验，找出发泡性能较好的渣系，研究渣中各成分对发泡性能的影响。     

Fuzzy adaptive networks in machining process modeling: surface roughness prediction for turning operations

Due to the complexity of the machine tool structure and the cutting process, the dynamics of machining processes are still not completely understood. This is especially true due to the demand of high-speed machining to increase productivity. In order to model and control these complex processes, new approaches, which can represent complex phenomenon combined with learning ability, are needed. The combined neural–fuzzy approach appears to be ideally suited for this purpose. In this paper, the recently developed fuzzy adaptive network (FAN) is used to model surface roughness in turning operations. The FAN network has both the learning ability of neural network and linguistic representation of complex, not well-understood, vague phenomenon. Furthermore, it can continuously improve the initially obtained rough model based on the daily operating data. To illustrate this approach, a model representing the influences of machining parameters on surface roughness is established and then the model is verified by the use of the results of pilot experiments. Finally, a comparison with the results based on statistical regression is provided.