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期刊论文 20

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关键词

CO2管道;离岸CCUS;海底管道;管道腐蚀;管道断裂;泄漏监测 1

PIC16F877A 1

RS—485总线 1

dsPIC30F4012 1

k-最近邻分类 1

主成分分析 1

云计算;侧信道攻击;信息泄露;多执行体架构;虚拟机切换;虚拟机迁移 1

光纤通信 1

图像分析 1

图像预处理 1

接触冲刷 1

控制 1

油气储运 1

泄漏 1

泄漏检测与定位 1

流网 1

海底碳封存;环境地质;CO2泄露;灾害风险;监测技术 1

漏电保护 1

现场可编程门阵列(FPGA);泄漏功率;电源门控;晶体管级电路设计 1

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Numerical and experimental analyses of methane leakage in shield tunnel

《结构与土木工程前沿(英文)》   页码 1011-1020 doi: 10.1007/s11709-023-0956-z

摘要: Tunnels constructed in gas-bearing strata are affected by the potential leakage of harmful gases, such as methane gas. Based on the basic principles of computational fluid dynamics, a numerical analysis was performed to simulate the ventilation and diffusion of harmful gases in a shield tunnel, and the effect of ventilation airflow speed on the diffusion of harmful gases was evaluated. As the airflow speed increased from 1.8 to 5.4 m/s, the methane emission was diluted, and the methane accumulation was only observed in the area near the methane leakage channels. The influence of increased ventilation airflow velocity was dominant for the ventilation modes with two and four fans. In addition, laboratory tests on methane leakage through segment joints were performed. The results show that the leakage process can be divided into “rapid leakage” and “slight leakage”, depending on the leakage pressure and the state of joint deformation. Based on the numerical and experimental analysis results, a relationship between the safety level and the joint deformation is established, which can be used as guidelines for maintaining utility tunnels.

关键词: shield tunnel     harmful gas leakage     numerical analysis     laboratory test    

Effects of leakage and friction on the miniaturization of a Wankel compressor

Yilin ZHANG, Wen WANG

《能源前沿(英文)》 2011年 第5卷 第1期   页码 83-92 doi: 10.1007/s11708-010-0125-7

摘要: This paper presents a numerical simulation of the performance of a meso-scale Wankel compressor and discusses the factors affecting its miniaturization. The discussion is related to the effect of leakage and friction on the design limit (cooling capacity and dimension) of the meso Wankel compressor. In the simulation, the main leakage comes from the gaps between the rotor and the endplates as well as between the seal apex and the cylinder. The largest friction originates from the clearance among the end face of the eccentric shaft, the end faces of the rotor, and the endplates. The decreasing cooling capacity of the meso Wankel compressor increases the proportion of leakage to displacement and causes the coefficient of performance COP and the mechanical efficiency to decrease. The rational design cooling capacity limit for the meso-scale Wankel compressor is approximately 4 W.

关键词: meso-scale     Wankel compressor     leakage     friction    

Cohesive zone model-based analyses of localized leakage of segmentally lined tunnels

《结构与土木工程前沿(英文)》 2023年 第17卷 第4期   页码 503-521 doi: 10.1007/s11709-023-0927-4

摘要: This paper presents a novel approach for simulating the localized leakage behavior of segmentally lined tunnels based on a cohesive zone model. The proposed approach not only simulates localized leakage at the lining segment, but also captures the hydromechanically coupled seepage behavior at the segmental joints. It is first verified via a tunnel drainage experiment, which reveals its merits over the existing local hydraulic conductivity method. Subsequently, a parametric study is conducted to investigate the effects of the aperture size, stratum permeability, and spatial distribution of drainage holes on the leakage behavior, stratum seepage field, and leakage-induced mechanical response of the tunnel lining. The proposed approach yields more accurate results than the classical local hydraulic conductivity method. Moreover, it is both computationally efficient and stable. Localized leakage leads to reduced local ground pressure, which further induces outward deformation near the leakage point and slight inward deformation at its diametrically opposite side. A localized stress arch spanning across the leakage point is observed, which manifests as the rotation of the principal stresses in the adjacent area. The seepage field depends on both the number and location of the leakage zones. Pseudostatic seepage zones, in which the seepage rate is significantly lower than that of the adjacent area, appear when multiple seepage zones are considered. Finally, the importance of employing the hydromechanical coupled mechanism at the segment joints is highlighted by cases of shallowly buried tunnels subjected to surface loading and pressure tunnels while considering internal water pressure.

关键词: segmentally lined tunnel     localized leakage     cohesive element     hydraulic behavior     numerical modeling    

Long-term settlement behavior of ground around shield tunnel due to leakage of water in soft deposit

Huaina WU, Yeshuang XU, Shui-long SHEN, Jin-chun CHAI

《结构与土木工程前沿(英文)》 2011年 第5卷 第2期   页码 194-198 doi: 10.1007/s11709-011-0105-y

摘要: The lining of shield tunnel is usually composed of segments, in which the joints, cracks, and the grouting holes (hereafter called lining deficit) exist. During the long-term running, soils and groundwater may leak from these kinds of lining deficit. The leaking of soil and groundwater causes the long-term ground loss around tunnel and thus results in the settlement of ground surface. This paper aims to analyze the impact of the leakage of groundwater through segments on the long-term settlement of ground surface. The adopted analytical method is based on the theory of groundwater seepage by using numerical simulation. The analyzed results show that settlement of ground surface increases gradually with the increase of the leaked volume of tunnel segments. When the leaked volume was unevenly distributed, differential settlement occurred locally. Comparative analysis by changing the leaked volume was conducted. The results reveal that there is a linear relationship between settlement and leaked volume when the leaked volume was controlled within the allowable limit.

关键词: lining deficit     leakage of water     shield tunnel     settlement     soft deposit    

A building unit decomposition model for energy leakage by infrared thermography image analysis

Yan SU, Fangjun HONG, Lianjie SHU

《能源前沿(英文)》 2020年 第14卷 第4期   页码 901-921 doi: 10.1007/s11708-020-0679-y

摘要: A quantitative energy leakage model was developed based on the thermography image data measured for both external and internal building surfaces. The infrared thermography images of both surfaces of doors, windows, and walls of an office building in the Hengqin Campus of University of Macao were taken at various times in a day for four seasons. The transient heat flux for sample units were obtained based on measurements of the seasonal transient local temperature differences and calculations of the effective thermal conductivity from the multiple-layer porous medium conduction model. Effects of construction unit types, orientations, and seasons were quantitatively investigated with unit transient orientation index factors. The corresponding electric energy consumption was calculated based on the air conditioning system coefficient of performance of heat pump and refrigerator cycles for different seasons. The model was validated by comparing to the electric meter records of energy consumption of the air conditioning system. The uncertainties of the predicted total building energy leakage are about 14.7%, 12.8%, 12.4%, and 15.8% for the four seasons, respectively. The differences between the predicted electric consumption and meter values are less than 13.4% and 5.4% for summer and winter, respectively. The typical daily thermal energy leakage value in winter is the highest among the four seasons. However, the daily electric energy consumption by the air conditioning system in summer and autumn is higher than that in winter. The present decomposition model for energy leakage is expected to provide a practical tool for quantitative analysis of energy leakage of buildings.

关键词: heat conductivity     heat coefficient     heat &fllig     ux     infrared thermography     thermal image    

Aggravation of membrane fouling and methane leakage by a three-phase separator in an external anaerobic

Chao Pang, Chunhua He, Zhenhu Hu, Shoujun Yuan, Wei Wang

《环境科学与工程前沿(英文)》 2019年 第13卷 第4期 doi: 10.1007/s11783-019-1131-6

摘要:

The existence of three-phase separator did not affect COD removal in the EAnCMBR.

The existence of three-phase separator aggravated methane leakage of EAnCMBR.

The existence of three-phase separator aggravated membrane fouling rate of EAnCMBR.

Start-up of EAnCMBR equipped three-phase separator was slightly delayed.

关键词: Anaerobic membrane bioreactor     Three-phase separator     Membrane fouling     Methane leakage     Sludge property    

在现场可编程门阵列中用于降低泄漏功率的动态电源门控 Research Article

Hadi JAHANIRAD

《信息与电子工程前沿(英文)》 2023年 第24卷 第4期   页码 582-598 doi: 10.1631/FITEE.2200084

摘要: 现场可编程门阵列(FPGA)器件由于其低设计成本和可重构性,在电子系统中得到广泛应用。在手持电子系统等电池受限的应用中,低功耗FGPA的需求很大。在现代集成电路技术中,泄漏功率几乎相当于动态功率,因此降低泄漏功率可以显著节省能耗。我们提出一种基于静态随机存取存储器(SRAM)的FPGA高效架构,其中每个模块定义了两种模式(活动模式和休眠模式)。在休眠模式下,模块消耗超低泄漏功率。当模块输出对新输入向量的评估时,模块模式由休眠模式动态改变为活动模式。在产生正确的输出后,该模块返回到休眠模式。所提电路设计在活动模式和休眠模式下都降低了泄漏功耗。通过在FPGA-SPICE软件上实现北卡罗来纳州微电子中心(MCNC)基准电路,将所提出的低泄漏FPGA体系结构与最先进的体系结构进行比较。仿真结果表明,休眠模式下泄漏功耗降低约95%。此外,与以往的最佳设计相比,总功耗(泄漏功耗+动态功耗)降低15%以上。平均面积开销(4.26%)小于其他电源门控设计。

关键词: 现场可编程门阵列(FPGA);泄漏功率;电源门控;晶体管级电路设计    

Leakage location system for oil pipeline on basis of stress wave detection

WANG Bangfeng, CHEN Renwen

《机械工程前沿(英文)》 2008年 第3卷 第3期   页码 307-312 doi: 10.1007/s11465-008-0047-9

摘要: An online monitoring system was developed for rapidly determining the exact location of the holing position in an oil pipeline by monitoring and analyzing the characteristics of the strain wave caused by the hole. The system has a master-slaver computer structure based on a remote wireless network. The master system takes charge of managing and controlling the whole system, identifying the holing stress wave, and calculating the holing position. The slaver system is responsible for sampling the strain wave signal from the pipeline. The characteristics of the strain wave signal are extracted by a Hilbert-Huang transform based on a signal processing approach. The exact holing position can be obtained by a time delay locating method with stress wave characteristics. The experimental results of the in-service pipeline show that the average locating error of the system is less than 10 m, the accuracy ratio for the holing alarm is more than 90%, and the time that the system takes to respond to the leakage is less than 10 s.

利用机器视觉技术对化工厂管道进行自动视觉泄漏检测与定位 Reiew

Mina Fahimipirehgalin, Emanuel Trunzer, Matthias Odenweller, Birgit Vogel-Heuser

《工程(英文)》 2021年 第7卷 第6期   页码 758-776 doi: 10.1016/j.eng.2020.08.026

摘要:

在大型化工厂中,输送液体的管道的泄漏是一个重要的问题。管道的破损不仅会影响工厂的正常运行,同时也增加了维护成本。此外,还会使操作人员的生命安全受到威胁。因此,管道泄漏的检测与定位是维护和状态监测中的关键任务。近年来,大型工厂利用红外(IR)相机进行泄漏检测。红外相机可捕捉温度比周围环境温度高(或低)的液体泄漏。本文针对化工厂中的管道泄漏,提出了一种基于红外视频数据和机器视觉技术的检测与定位方法。由于所提出的方法是以视觉技术为基础,无需考虑泄漏液体的物理性质,因此其适用于任何类型的液体(水、油等)泄漏检测。在本方法中,首先对后续帧进行减影和分块处理,然后对每一分块进行主成分分析,提取特征;接着将分块内所有减影帧都转换为特征向量(作为块分类的依据),根据特征向量,采用k-最近邻算法将块分为正常(无泄漏)和异常(泄漏)两类;最后在各异常块上确定泄漏的位置。本文使用了两种不同格式的数据集(由红外相机拍摄的实验室工厂演示装置的视频图像组成)对上述方法进行评估。结果表明,本文提出的利用红外视频进行管道泄漏检测与定位的方法前景可观,具有较高的检测精度以及合理的检测时间。本文最后讨论了该方法在工厂进行实际推广的可能性及局限性。

关键词: 泄漏检测与定位     图像分析     图像预处理     主成分分析     k-最近邻分类    

Modeling and analysis of magnetic dipoles in weak magnetic field

WANG Zhaoxia, ZHANG Weimin, LIU Hongguang

《机械工程前沿(英文)》 2008年 第3卷 第2期   页码 222-225 doi: 10.1007/s11465-008-0028-z

摘要: The magnetic leakage field distribution resulting from linear defects of a tube sample in the geomagnetic field is modeled according to the magnetic dipole theory. The formula to compute the normal component of the weak magnetic field is deduced based on the spatial distribution of the magnetic dipole. The shape and characteristics of the zero line (an important criterion for magnetic memory testing) of the normal field is analyzed under different longitudinal magnetizations. Results show that the characteristics of the zero line should be considered when the metal magnetic memory testing method is used to find and locate the defect.

关键词: geomagnetic     theory     important criterion     magnetic leakage     normal component    

矿井低压电网选择性漏电保护系统总体设计与实现

孙玉坤,朱志莹,黄振跃,唐平

《中国工程科学》 2012年 第14卷 第7期   页码 93-97

摘要:

设计了一款以dsPIC30F4012为主控制器、PIC16F877A为从处理器的新型主从式选择性漏电保护系统。该系统在总开关处采用附加直流源检测原理检测是否发生漏电,在分支开关处使用零序功率方向检测原理判断发生漏电故障线路,给出了保护系统的硬件框图和软件流程图,并且采用速度更快的RS—485总线及光纤传输技术,实现了矿井低压电网漏电保护的瞬动性。实验结果验证了该保护系统的优越性能。

关键词: 漏电保护     选择性     dsPIC30F4012     PIC16F877A     RS—485总线     光纤通信    

接触冲刷发展过程模拟研究

陈建生,刘建刚,焦月红

《中国工程科学》 2003年 第5卷 第7期   页码 33-39

摘要:

为研究堤基接触冲刷渗透破坏机理,对粘土层与砂砾石层之间各种成因的粗糙面或缝隙渗透性用光滑裂隙的渗透性代替,地层整体的渗透性由裂隙、砾石层和砂砾石层的渗透性决定,以细砂的起动速度为判别标准,通过分时段的稳定流计算,接触面附近的细砂从出渗口开始流出,出渗口附近的渗透系数首先增大,然后逐步向内部发展,以垂直河岸方向的发展最为迅速,甚至形成贯通性集中渗漏通道。

关键词: 接触冲刷     起动速度     流网     集中渗漏通道    

Experimental study of pollution effect on the behavior of high voltage insulators under alternative current

Hani BENGUESMIA, Nassima M’ZIOU, Ahmed BOUBAKEUR

《能源前沿(英文)》 2021年 第15卷 第1期   页码 213-221 doi: 10.1007/s11708-017-0479-1

摘要: In this paper, the impact of the conductivity and the distribution of pollution on the behavior of the high voltage insulator cap and pin 1512L, artificially polluted is described. An experimental model in form of a disc is proposed. This experimental model reproduces the real model which is the 1512L insulator. Besides, a comparative study is presented. For this comparative study, different solutions are adopted to s`imulate the pollution (containing NaCl+ distilled water) that has different conductivities for a discontinuous distribution of the pollution on the insulator under an AC voltage. Furthermore, the influence of the pollution on the flashover voltage and the leakage current is studied. Finally, the behavior of real and experimental model of the insulator is investigated.

关键词: 1512L insulator     circular model     artificial pollution     flashover     leakage current     discontinuous pollution     high voltage    

Performance improvement of a pulse tube cryocooler with a single compressor through cascade utilization of cold energy

Xuming LIU, Xiafan XU, Biao YANG, Xiaotong XI, Liubiao CHEN, Junjie WANG, Yuan ZHOU

《能源前沿(英文)》 2021年 第15卷 第2期   页码 345-357 doi: 10.1007/s11708-020-0708-x

摘要: The high-frequency pulse tube cryocooler (HPTC) has been attracting increasing and widespread attention in the field of cryogenic technology because of its compact structure, low vibration, and reliable operation. The gas-coupled HPTC, driven by a single compressor, is currently the simplest and most compact structure. For HPTCs operating below 20 K, in order to obtain the mW cooling capacity, hundreds or even thousands of watts of electrical power are consumed, where radiation heat leakage accounts for a large proportion of their cooling capacity. In this paper, based on SAGE10, a HPTC heat radiation calculation model was first established to study the effects of radiation heat leakage on apparent performance parameters (such as temperature and cooling capacity), and internal parameters (such as enthalpy flow and gas distribution) of the gas-coupled HPTC. An active thermal insulation method of cascade utilization of the cold energy of the system was proposed for the gas-coupled HPTC. Numerical simulations indicate that the reduction of external radiation heat leakage cannot only directly increase the net cooling power, but also decrease the internal gross losses and increase the mass and acoustic power in the lower-temperature section, which further enhances the refrigeration performance. The numerical calculation results were verified by experiments, and the test results showed that the no-load temperature of the developed cryocooler prototype decreased from 15.1 K to 6.4 K, and the relative Carnot efficiency at 15.5 K increased from 0.029% to 0.996% when substituting the proposed active method for the traditional passive method with multi-layer thermal insulation materials.

关键词: radiation heat leakage     active thermal insulation     cascade utilization     cold energy     performance improvement     cryocooler    

Adaptive robust beamformer formulti-pair two-way relay networks with imperfect channel state information

Jin WANG,Feng SHU,Ri-qing CHEN,Yu-di CUI,Yu CHEN,Jun LI

《信息与电子工程前沿(英文)》 2016年 第17卷 第3期   页码 265-280 doi: 10.1631/FITEE.1500134

摘要: In wideband multi-pair two-way relay networks, the performance of beamforming at a relay station (RS) is intimately related to the accuracy of the channel state information (CSI) available. The accuracy of CSI is determined by Doppler spread, delay between beamforming and channel estimation, and density of pilot symbols, including transmit power of pilot symbols. The coefficient of the Gaussian-Markov CSI error model is modeled as a function of CSI delay, Doppler spread, and signal-to-noise ratio, and can be estimated in real time. In accordance with the real-time estimated coefficients of the error model, an adaptive robust maximum signal-to-interferenceand- noise ratio (Max-SINR) plus maximum signal-to-leakage-and-noise ratio (Max-SLNR) beamformer at an RS is proposed to track the variation of the CSI error. From simulation results and analysis, it is shown that: compared to existing non-adaptive beamformers, the proposed adaptive beamformer is more robust and performs much better in the sense of bit error rate (BER); with increase in the density of transmit pilot symbols, its BER and sum-rate performances tend to those of the beamformer of Max-SINR plus Max-SLNR with ideal CSI.

关键词: Multi-pair two-way relay     Adaptive robust beamformer     Channel state information (CSI)     Maximum signal-to-interference-and-noise ratio (Max-SINR)     Maximum signal-to-leakage-and-noise ratio (Max-SLNR)    

标题 作者 时间 类型 操作

Numerical and experimental analyses of methane leakage in shield tunnel

期刊论文

Effects of leakage and friction on the miniaturization of a Wankel compressor

Yilin ZHANG, Wen WANG

期刊论文

Cohesive zone model-based analyses of localized leakage of segmentally lined tunnels

期刊论文

Long-term settlement behavior of ground around shield tunnel due to leakage of water in soft deposit

Huaina WU, Yeshuang XU, Shui-long SHEN, Jin-chun CHAI

期刊论文

A building unit decomposition model for energy leakage by infrared thermography image analysis

Yan SU, Fangjun HONG, Lianjie SHU

期刊论文

Aggravation of membrane fouling and methane leakage by a three-phase separator in an external anaerobic

Chao Pang, Chunhua He, Zhenhu Hu, Shoujun Yuan, Wei Wang

期刊论文

在现场可编程门阵列中用于降低泄漏功率的动态电源门控

Hadi JAHANIRAD

期刊论文

Leakage location system for oil pipeline on basis of stress wave detection

WANG Bangfeng, CHEN Renwen

期刊论文

利用机器视觉技术对化工厂管道进行自动视觉泄漏检测与定位

Mina Fahimipirehgalin, Emanuel Trunzer, Matthias Odenweller, Birgit Vogel-Heuser

期刊论文

Modeling and analysis of magnetic dipoles in weak magnetic field

WANG Zhaoxia, ZHANG Weimin, LIU Hongguang

期刊论文

矿井低压电网选择性漏电保护系统总体设计与实现

孙玉坤,朱志莹,黄振跃,唐平

期刊论文

接触冲刷发展过程模拟研究

陈建生,刘建刚,焦月红

期刊论文

Experimental study of pollution effect on the behavior of high voltage insulators under alternative current

Hani BENGUESMIA, Nassima M’ZIOU, Ahmed BOUBAKEUR

期刊论文

Performance improvement of a pulse tube cryocooler with a single compressor through cascade utilization of cold energy

Xuming LIU, Xiafan XU, Biao YANG, Xiaotong XI, Liubiao CHEN, Junjie WANG, Yuan ZHOU

期刊论文

Adaptive robust beamformer formulti-pair two-way relay networks with imperfect channel state information

Jin WANG,Feng SHU,Ri-qing CHEN,Yu-di CUI,Yu CHEN,Jun LI

期刊论文