Using the curve moment and the PSO-SVM method to diagnose downhole conditions of a sucker rod pumping unit

Downhole working conditions of sucker rod pumping wells are automatically identified on a computer from the analysis of dynamometer cards. In this process, extraction of feature parameters and pattern classification are two key steps. The dynamometer card is firstly divided into four parts which include different production information according to the "four point method" used in actual oilfield production, and then the moment invariants for pattern recognition are extracted. An improved support vector machine (SVM) method is used for pattern classification whose error penalty parameter C and kernel function parameter g are optimally chosen by the particle swarm optimization (PSO) algorithm. The simulation results show the method proposed in this paper has good classification results.     

Characteristics of Convection Heat Transfer in Power-Law Fluid Saturated Porous Media Channel

幂律流体饱和多孔介质通道内对流换热特性

田兴旺¹,张琨¹,刘峰¹,王平²,徐士鸣²

（1.大连海洋大学 海洋与土木工程学院,辽宁 大连 116023;2.大连理工大学 能源与动力工程学院,辽宁 大连 116024）

摘 要：

基于Darcy-Brinkman-Forchheimer流动模型和局部非热平衡模型,考虑黏性耗散效应的影响,建立了幂律流体在多孔介质通道内流动传热的一般模型。推导出无量纲速度分布和流、固温度分布的计算表达式,并在恒热流边界条件下,利用经典的四阶Runge-Kutta法进行了自编程序的数值求解。模拟结果表明,无量纲的相间传热系数Bi、有效导热系数比k、达西数Da,布林克曼数Br、综合惯性参数F等表征参数对无量纲流、固温度分布有着较大的影响,同时发现不同幂律指数的流体对流动传热特性也有着重要的影响。

关键词：粘性耗散;幂律流体;多孔介质;局部非热平衡;数值模拟

     

Adaptability to geological faulted foundation of Hardfill dam

Hardfill dam is a new type of dam which has the advantages of low stress level and even stress distribution in a dam body, resulting in low demands to foundations. Based on 2D linear elastic and elasto-plastic calculations of gravity dam and Hardfill dam using finite element method (FEM), the stress distribution in a dam body and anti-sliding stabilization is analyzed on the geological faulted foundations with weak weathered rock and soft interlayers. It is concluded that Hardfill dams have better adaptability to geological faulted foundations than gravity dams and is more secure and economically sound.     

Crystal modification of rifapentine using different solvents

Rifapentine crystals with different habits were prepared by recrystallization from selected solvents, such as methanol, ethanol, chloroform, and acetic acid. Scanning electron microscopy, X-ray powder diffractometry, infrared spectrometry, and differential scanning calorimetry were used to investigate the physicochemical characteristics of the prepared crystals. The comparative dissolution behaviors of the newly developed crystals and of rifapentine without being treated were also studied. Results show that the newly developed crystals were different from each other with respect to physical properties but were identical chemically. Needle-shaped crystals were obtained from methanol, ethanol, and chloroform solvents, and the block-shaped crystals were obtained from acetic acid solvent. X-ray diffraction spectra and differential scanning calorimetry investigation on those developed crystals clearly indicate that rifapentine has different crystal structure modification. When the crystal was obtained from acetic acid, the change of crystal habit was originated from the crystal structure modification. The dissolution rate of newly developed crystals was found to be higher than that of rifapentine without being treated. However, the modified crystal obtained from acetic acid shows the lower dissolution rate than crystals obtained from other solvents.     

机械设备及自动化专业教学改革和实践

<正> 机械设备及自动化专业是我院省重点教学改革试点专业,经过了四年的教学改革和实践,完成了一届学生(95机电班)教学改革的试点工作,取得了教学改革的突出成果。1 根据市场经济需要,确立教学改革思路 随着微电子技术、计算机技术的迅猛发展和强力渗透,机械工程领域正在产生一场深刻的技术革命,表现为微电子技术、计算机技术、检测技术、自动控制技术、系统论、信息论等现代科学技术与机械技术的高度结合。这种高度结合的机电一体化产品大量涌现,促进了机械工程工业向高速、高效、高自动化方向发展。促使整个国民经济的飞跃发展。 我国改革开放逐步转入社会主义市场经济体制轨道,要求机械工程工业适应多品种、中小批量柔性自动化生产,以满足社会各方面的需求。苏南地区特别是常州地区,外向型经济的蓬勃发展,对机械工程的自动化提出了更高的要求。     

Electronic structures and properties of Ti, Zr and Hf metals

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From single- to multi-modal remote sensing imagery interpretation: a survey and taxonomy

Modality is a source or form of information. Through various modal information, humans can perceive the world from multiple perspectives. Simultaneously, the observation of remote sensing(RS) is multimodal. We observe the world macroscopically through panchromatic, Lidar, and other modal sensors.Multimodal observation of remote sensing has become an active area, which is beneficial for urban planning,monitoring, and other applications. Despite numerous advancements in this area, there has still ...     

NeuralReshaper: single-image human-body retouching with deep neural networks

<正>Semantic retouching of human bodies in images, such as increasing the height and slimming the body, has been long desired. However, the problem is essentially ill-posed because one should anticipate a set of articulated and nonrigid deformations of different body parts, given that the deformations are inherently three-dimensional.     

人工智能在化学逆合成中的应用（英文）

近年来,人们对通过人工智能（AI）技术解决化学逆合成预测问题产生了巨大的兴趣。与化学家和基于规则的专家系统进行的逆合成预测不同,AI驱动的逆合成预测自动从现成的实验数据集中学习化学知识,以预测反应和逆合成路径。这提供了解决许多传统挑战的机会,包括专业知识过于繁杂、路线的长度过大和计算成本高。本文描述了当前AI驱动的逆合成预测的概况。我们首先讨论了化学逆合成的数学定义,并回顾了这个问题中的研究挑战。然后,我们回顾相关的AI技术和最新进度,以实现逆合成预测。此外,我们提供了逆合成系统不同部分的全面分类,并调查了AI方法如何重塑每个子模块。最后,我们讨论了未来有希望的研究领域。     

Cleaning RFID data streams based on K-means clustering method

Currentlyradio frequency identification (RFID) technology has been widely used in many kinds of applications. Store retailers use RFID readers with multiple antennas to monitor all tagged items. However, because of the interference from environment and limitations of the radio frequency technology, RFID tags are identified by more than one RFID antenna, leading to the false positive readings. To address this issue, we propose a RFID data stream cleaning method based on K-means to remove those false positive readings within sampling time. First, we formulate a new data stream model which adapts to our cleaning algorithm. Then we present the preprocessing method of the data stream model, including sliding window setting, feature extraction of data stream and normalization. Next, we introduce a novel way using K-means clustering algorithm to clean false positive readings. Last, the effectiveness and efficiency of the proposed method are verified by experiments. It achieves a good balance between performance and price.