资源类型

期刊论文 77

会议视频 1

年份

2023 5

2022 6

2021 8

2020 10

2019 5

2018 3

2017 7

2016 5

2015 3

2014 2

2013 1

2012 5

2011 1

2010 6

2008 2

2007 2

2006 2

2005 2

1999 1

展开 ︾

关键词

微波遥感 2

无源微地震 2

60 GHz；封装天线；共面波导馈电环形谐振器；玻璃集成无源器件；超表面天线；小型化天线 1

BFT 1

CAP1400 1

GVG农情采样系统 1

Gibbs抽样 1

HPR1000 1

HY-2A卫星 1

Laplacian特征映射 1

MCMC模拟 1

PCB缺陷检测 1

PIM源定位 1

TMA 1

Weibull分布 1

mcr 1

个人热管理 1

主动源面波 1

主动视觉 1

展开 ︾

检索范围：

排序： 展示方式：

基于重要性采样的TOA与FOA无源定位算法 Article

Rui-rui LIU, Yun-long WANG, Jie-xin YIN, Ding WANG, Ying WU

《信息与电子工程前沿（英文）》 2017年 第18卷 第8期   页码 1167-1179 doi: 10.1631/FITEE.1601657

摘要： 最大似然类的无源定位方法可以达到较高的定位精度，但其计算量非常大。由于时频参数联合定位模型本身的非线性和非凸性非常大，繁重的计算量在TOA与FOA联合定位系统中表现尤为明显。本文针对这一问题，通过Pincus全局最优理论和蒙特卡洛重要性采样技术降低了最大似然类定位算法的计算复杂度，并且保证算法可以收敛到全局最优解。本文主要的贡献是构建了一个高斯分布的概率密度函数来近似原始的代价函数方便后续的采样，我们称之为重要性函数。该方法所带来性能上的提升是因为选择了最优的重要性函数并且Pincus保证算法收敛到全局最小值。这一处理大大降低了计算量，由于算法进行了泰勒级数展开，需要初始估计值。通过采样处理并且对样本进行加权，本文算法对初始估计值具有良好的鲁棒性。最后，实验证明本文所提算法可以达到克拉美罗限，且性能要优于现有算法。

关键词： 无源定位；到达时间；到达频率；蒙特卡洛重要性采样；最大似然估计    

HTML PDF 收藏

Diffusive gradients in thin films using molecularly imprinted polymer binding gels for in situ measurements of antibiotics in urban wastewaters

Ying Cui, Feng Tan, Yan Wang, Suyu Ren, Jingwen Chen

《环境科学与工程前沿（英文）》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1290-5

摘要： Abstract • Selective molecularly imprinted polymer (MIP) binding gel was prepared. • MIP-DGT showed excellent uptake performance for antibiotics. • In situ measurement of antibiotics in wastewaters via MIP-DGT was developed. • The MIP-DGT method was robust, reliable, and highly sensitive. Urban wastewater is one of main sources for the introduction of antibiotics into the environment. Monitoring the concentrations of antibiotics in wastewater is necessary for estimating the amount of antibiotics discharged into the environment through urban wastewater treatment systems. In this study, we report a novel diffusive gradient in thin films (DGT) method based on molecularly imprinted polymers (MIPs) for in situ measurement of two typical antibiotics, fluoroquinolones (FQs) and sulfonamides (SAs) in urban wastewater. MIPs show specific adsorption toward their templates and their structural analogs, resulting in the selective uptake of the two target antibiotics during MIP-DGT deployment. The uptake performance of the MIP-DGTs was evaluated in the laboratory and was relatively independent of solution pH (4.0–9.0), ionic strength (1–750 mmol/L), and dissolved organic matter (DOM, 0–20 mg/L). MIP-DGT samplers were tested in the effluent of an urban wastewater treatment plant for field trials, where three SA (sulfamethoxazole, sulfapyridine, and trimethoprim) and one FQ (ofloxacin) antibiotics were detected, with concentrations ranging from 25.50 to 117.58 ng/L, which are consistent with the results measured by grab sampling. The total removal efficiency of the antibiotics was 80.1% by the treatment plant. This study demonstrates that MIP-DGT is an effective tool for in situ monitoring of trace antibiotics in complex urban wastewaters.

关键词： Diffusive gradients in thin films     Molecularly imprinted polymers     Selective uptake     Antibiotics     Passive sampling    

HTML PDF 收藏

Numerical simulation and experimental research on the wheel brush sampling process of an asteroid sampler

《机械工程前沿（英文）》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0732-0

摘要： To examine the environmental characteristics of the microgravity force and the weathered layer on an asteroid surface, a symmetric wheel brush asteroid sampler is proposed for the collection of particles on the asteroid surface. To study the influence of the wheel brush rotation speed on the sampling efficiency and the driving torque required for the wheel brush, the contact dynamics model between particles and sampling wheel brushes is established and a simulation and experimental verification of the sampling process are conducted. The parameter calibration of the sampled particles is studied first, and the calibrated particle parameters are used in the numerical simulation of the sampling process. The sampling results and the particle stream curves are obtained for the working conditions of different rotation speeds, and the effects of different parameter settings on the sampling efficiency are analyzed. In addition, a set of rotating symmetrical sampling wheel brush devices is built for the ground test, and the dynamic torque sensor is used to test the torque change of the wheel brush during the sampling process. The relationship between the speed of the wheel brush and the driving torque of the wheel brush motor is determined by comparing the simulation results with the test results. Results indicate that when the rotating speed of the wheel brush is faster, the sampling efficiency is higher, and the driving torque required for the sampling wheel brush is greater. Moreover, a numerical simulation analysis of the sampling process of the wheel brush sampler in a microgravity environment is conducted to determine the optimal speed condition, and the brushing test of the wheel brush sampler in the microgravity environment is verified with the drop tower method. This research proposes the structural optimization design and motor selection of a wheel brush asteroid sampler, which provides important reference value and engineering significance.

关键词： asteroid sampling     wheel brush sampler     discrete element method     parameter calibration     experimental research    

HTML PDF 收藏

Mechanistic insight into the biofilm formation and process performance of a passive aeration ditch (PAD

《环境科学与工程前沿（英文）》 2022年 第16卷 第7期 doi: 10.1007/s11783-021-1494-3

摘要：

• A Passive Aeration Ditch was developed to treat decentralized wastewater.

关键词： Decentralized wastewater     Passive aeration ditch     Biofilm formation     C/N ratio     Salinity     Model simulation    

HTML PDF 收藏

Numerical modeling and performance evaluation of passive convergence-permeable reactive barrier (PC-PRB

《环境科学与工程前沿（英文）》 2023年 第17卷 第11期 doi: 10.1007/s11783-023-1731-z

摘要：

● A 2D finite-element solute transport model, PRB-Trans, is developed.

关键词： Passive convergence-permeable reactive barrier     Numerical modeling     Hydraulic behavior assessment     Pollutant treatment performance evaluation     Influential factors analysis    

HTML PDF 收藏

Investigation on sampling artifacts of particle associated PAHs using ozone denuder systems

Kai LIU, Fengkui DUAN, Kebin HE, Yongliang MA, Yuan CHENG

《环境科学与工程前沿（英文）》 2014年 第8卷 第2期   页码 284-292 doi: 10.1007/s11783-013-0555-7

摘要： Polycyclic aromatic hydrocarbons (PAHs) are complex organic compounds which are identified as significant carcinogenic to human health. PAHs (mainly in particle phase) are susceptible to atmospheric oxidant gases, especially ozone, nitrogen oxides (NO ), hydroxyl radical (OH), and could be degraded on filters during sampling process, leading to an underestimation of ambient PAH concentrations. The goal of this work was to investigate particle associated PAHs sampling artifacts caused by ozone in summer of Beijing. Comparative sampling systems were operated simultaneously during the whole campaign, one with activated carbon ozone denuder, the other being set as conventional sampling system. Activated carbon denuder was testified to be highly efficient to eliminate ozone from air stream. In general, nine particle-bound PAHs observed from conventional sampler were all lower than those from ozone denuder system. The total PAHs (particle phase) concentration was averagely underestimated by 35.9% in conventional sampling procedure. Benzo[a]pyrene (BaP) had the highest percentage of mass loss. Ambient temperature was founded to have influences on PAHs sampling artifacts. High temperature can increase loss of particle associated PAHs during sampling.

关键词： particle associated polycyclic aromatic hydrocarbons (PAHs)     ozone     denuder     sampling artifacts    

HTML PDF 收藏

A sampling method based on URL clustering for fast web accessibility evaluation

Meng-ni ZHANG,Can WANG,Jia-jun BU,Zhi YU,Yu ZHOU,Chun CHEN

《信息与电子工程前沿（英文）》 2015年 第16卷 第6期   页码 449-456 doi: 10.1631/FITEE.1400377

摘要： When evaluating the accessibility of a large website, we rely on sampling methods to reduce the cost of evaluation. This may lead to a biased evaluation when the distribution of checkpoint violations in a website is skewed and the selected samples do not provide a good representation of the entire website. To improve sampling quality, stratified sampling methods first cluster web pages in a site and then draw samples from each cluster. In existing stratified sampling methods, however, all the pages in a website need to be analyzed for clustering, causing huge I/O and computation costs. To address this issue, we propose a novel page sampling method based on URL clustering for web accessibility evaluation, namely URLSamp. Using only the URL information for stratified page sampling, URLSamp can efficiently scale to large websites. Meanwhile, by exploiting similarities in URL patterns, URLSamp cluster pages by their generating scripts and can thus effectively detect accessibility problems from web page templates. We use a data set of 45 web sites to validate our method. Experimental results show that our URLSamp method is both effective and efficient for web accessibility evaluation.

关键词： Page sampling     URL clustering     Web accessibility evaluation    

HTML PDF 收藏

Parametric control of structural responses using an optimal passive tuned mass damper under stationary

Min-Ho CHEY, Jae-Ung KIM

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 267-280 doi: 10.1007/s11709-012-0170-x

摘要： In this study, the structural control strategy utilizing a passive tuned mass damper (TMD) system as a seismic damping device is outlined, highlighting the parametric optimization approach for displacement and acceleration control. The theory of stationary random processes and complex frequency response functions are explained and adopted. For the vibration control of an undamped structure, the optimal parameters of a TMD, such as the optimal tuning frequency and optimal damping ratio, to stationary Gaussian white noise acceleration are investigated by using a parametric optimization procedure. For damped structures, a numerical searching technique is used to obtain the optimal parameters of the TMD, and then the explicit formulae for these optimal parameters are derived through a sequence of curve-fitting schemes. Using these specified optimal parameters, several different controlled responses are examined, and then the displacement and acceleration based control effectiveness indices of the TMD are examined from the view point of RMS values. From the viewpoint of the RMS values of displacement and acceleration, the optimal TMDs adopted in this study shows clear performance improvements for the simplified model examined, and this means that the effective optimization of the TMD has a good potential as a customized target response-based structural strategy.

关键词： tuned mass damper     parametric optimization     passive control     white noise     earthquake excitation    

HTML PDF 收藏

Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault

Hamed HABIBI, Hamed RAHIMI NOHOOJI, Ian HOWARD

《机械工程前沿（英文）》 2017年 第12卷 第3期   页码 377-388 doi: 10.1007/s11465-017-0431-4

摘要：

Power maximization has always been a practical consideration in wind turbines. The question of how to address optimal power capture, especially when the system dynamics are nonlinear and the actuators are subject to unknown faults, is significant. This paper studies the control methodology for variable-speed variable-pitch wind turbines including the effects of uncertain nonlinear dynamics, system fault uncertainties, and unknown external disturbances. The nonlinear model of the wind turbine is presented, and the problem of maximizing extracted energy is formulated by designing the optimal desired states. With the known system, a model-based nonlinear controller is designed; then, to handle uncertainties, the unknown nonlinearities of the wind turbine are estimated by utilizing radial basis function neural networks. The adaptive neural fault tolerant control is designed passively to be robust on model uncertainties, disturbances including wind speed and model noises, and completely unknown actuator faults including generator torque and pitch actuator torque. The Lyapunov direct method is employed to prove that the closed-loop system is uniformly bounded. Simulation studies are performed to verify the effectiveness of the proposed method.

关键词： wind turbine nonlinear model     maximum power tracking     passive fault tolerant control     adaptive neural control    

HTML PDF 收藏

Dilution sampling and analysis of particulate matter in biomass-derived syngas

Xiaoliang WANG, Curtis ROBBINS, S. Kent HOEKMAN, Judith C. CHOW, John G. WATSON, Dennis SCHUETZLE

《环境科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 320-330 doi: 10.1007/s11783-011-0347-x

摘要： Thermochemical biomass gasification, followed by conversion of the produced syngas to fuels and electrical power, is a promising energy alternative. Real-world characterization of particulate matter (PM) and other contaminants in the syngas is important to minimize damage and ensure efficient operation of the engines it powers and the fuels created from it. A dilution sampling system is demonstrated to quantify PM in syngas generated from two gasification plants utilizing different biomass feedstocks: a BioMax 15 Biopower System that uses raw and torrefied woodchips as feedstocks, and an integrated biorefinery (IBR) that uses rice hulls and woodchips as feedstocks. PM mass concentrations in syngas from the IBR downstream of the purification system were 12.8–13.7 μg·m , which were significantly lower than the maximum level for catalyst protection (500 μg·m ) and were 2–3 orders of magnitude lower than those in BioMax 15 syngas (2247–4835 μg·m ). Ultrafine particle number concentration and PM chemical constituents were also much lower in the IBR syngas than in the BioMax 15. The dilution sampling system enabled reliable measurements over a wide range of concentrations: the use of high sensitivity instruments allowed measurement at very low concentrations (~1 μg·m ), while the flexibility of dilution minimized sampling problems that are commonly encountered due to high levels of tars in raw syngas (~1 g·m ).

关键词： dilution source sampling     syngas characterization     biomass gasification     ultrafine particles    

HTML PDF 收藏

Recent developments in passive interconnected vehicle suspension

Wade A. SMITH, Nong ZHANG,

《机械工程前沿（英文）》 2010年 第5卷 第1期   页码 1-18 doi: 10.1007/s11465-009-0092-z

摘要： This paper presents an overall review on the historical concept development and research advancement of passive hydraulically interconnected suspension (HIS) systems. It starts with an introduction to passive HIS systems and their various incarnations developed over many decades. Next, a description is provided of a recently proposed multidisciplinary approach for the frequency-domain analysis of vehicles fitted with an HIS. The experimental validation and applications of the method to both free and forced vibration analysis are discussed based on a simplified, roll-plane half-car model. A finite-element-method-based approddach for modelling the transient dynamics of an HIS vehicle is also briefly outlined. In addition, recent work on the investigation of NVH associated with HIS-equipped vehicles is mentioned. Discussion is then provided on future work to the further understanding of HIS and its applications. The paper concludes that interconnected suspension schemes can provide much greater flexibility to independently specify modal stiffness and damping parameters – a characteristic unique among passive suspensions. It points out that there is a need for system optimisation, and there are troublesome NVH issues that require solutions. It suggests that further research attention and effort be paid to NVH issues and system level optimisation to gain a greater understanding of HIS and to broaden its applications.

关键词： interconnected suspensions     rollover prevention     vehicle dynamics     ride comfort     multibody system dynamics     hydraulic system dynamics    

HTML PDF 收藏

Moving target detection in the cepstrum domain for passive coherent location (PCL) radar

Ji-chuan LI,Xiao-de LU,Hui ZHANG,Peng-cheng YANG,Yu LIU,Mao-sheng XIANG

《信息与电子工程前沿（英文）》 2015年 第16卷 第9期   页码 785-795 doi: 10.1631/FITEE.1500036

摘要： A cepstrum moving target detection (CEPMTD) algorithm based on cepstrum techniques is proposed for passive coherent location (PCL) radar systems. The primary cepstrum techniques are of great success in recognizing the arrival times of static target echoes. To estimate the Doppler frequencies of moving targets, we divide the radar data into a large number of segments, and reformat these segments into a detection matrix. Applying the cepstrum and the Fourier transform to the fast and slow time dimensions respectively, we can obtain the range information and Doppler information of the moving targets. Based on the CEPMTD outlined above, an improved CEPMTD algorithm is proposed to improve the detection performance. Theoretical analyses show that only the target’s peak can be coherently added. The performance of the improved CEPMTD is initially validated by simulations, and then by experiments. The simulation results show that the detection performance of the improved CEPMTD algorithm is 13.3 dB better than that of the CEPMTD algorithm and 6.4 dB better than that of the classical detection algorithm based on the radar cross ambiguity function (CAF). The experiment results show that the detection performance of the improved CEPMTD algorithm is 1.63 dB better than that of the radar CAF.

关键词： Moving target detection     Cepstrum techniques     Cross ambiguity function (CAF)     Passive coherent location (PCL) radar    

HTML PDF 收藏

A state-of-the-art review of solar passive building system for heating or cooling purpose

Arun Kumar NANDA,C K PANIGRAHI

《能源前沿（英文）》 2016年 第10卷 第3期   页码 347-354 doi: 10.1007/s11708-016-0403-0

摘要： The major portion of energy in a building is consumed by heating, ventilating, and air-conditioning (HVAC). The traditional heating and cooling systems contribute greatly to the emission of greenhouse gases, especially carbon dioxide. Four different ways, i.e., Trombe wall, solar chimney, unglazed transpired solar façade, and solar roof, are adopted for solar heating. Similarly, two major ways, i.e., evaporative cooling and building integrated evaporative cooling are adopted for cooling of the building. Therefore, an attempt has been made in this paper to compile the developments of solar heating and cooling technologies in a building.

关键词： HVAC     heating     cooling     solar heating     carbon dioxide (CO2) emissions    

HTML PDF 收藏

Unified methodology for site-characterization and sampling of highway runoff

Jy S. WU, Craig J. ALLAN,

《环境科学与工程前沿（英文）》 2010年 第4卷 第1期   页码 47-58 doi: 10.1007/s11783-010-0003-x

摘要： Hydrology, roadway traffic conditions, and atmospheric deposition are three essential data categories for the planning and implementation of highway-runoff monitoring and characterization programs. Causal variables pertaining to each data category could be site specific but have been shown to correlate with runoff pollutant loads. These data categories were combined to derive statistical relationships for characterization and prioritization of the respective pollutant loads at highway runoff sites. Storm runoff data of total suspended solids (TSS), total dissolved solid (TDS), chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN) and total phosphorus (TP) collected from three highway sites in Charlotte, North Carolina, USA, were used to illustrate the development of site-specific highway-runoff pollutant loading models. This unified methodology provides a basis for initial assessment of the pollutant-constituent loads from highway runoff using hydrologic component variables. Improved reliability is achievable when additional traffic and/or atmospheric component variables are incorporated into the basic hydrologic regression model. In addition, operational guidance is suggested for implementing highway-runoff monitoring programs that are subject to sampling and resources constraints.

关键词： highway runoff     pollutant loads     regression models     non-point source pollution     storm water permit    

HTML PDF 收藏

单站无源定位可观测性评述

邓新蒲

《中国工程科学》 2007年 第9卷 第11期   页码 54-62

摘要：

可观测性分析是单观测器无源定位首先要研究的问题，只有当目标状态 (位置、速度等)是完全可观测的，定位和跟踪问题才能有可靠的、唯一的解。从几何方法、代数方程方法、线性系统方法3方面来阐述单站测角无源定位的状态可观性问题，讨论测频单站无源定位问题的可观测性和定量的可观测性，并对近年来这一领域的相关文献的分析方法和结论进行评述。

关键词： 无源定位     TMA     可观测性    

HTML PDF 收藏

标题 作者 时间 类型 操作

基于重要性采样的TOA与FOA无源定位算法

Rui-rui LIU, Yun-long WANG, Jie-xin YIN, Ding WANG, Ying WU

期刊论文

Diffusive gradients in thin films using molecularly imprinted polymer binding gels for in situ measurements of antibiotics in urban wastewaters

Ying Cui, Feng Tan, Yan Wang, Suyu Ren, Jingwen Chen

期刊论文

Numerical simulation and experimental research on the wheel brush sampling process of an asteroid sampler

期刊论文

Mechanistic insight into the biofilm formation and process performance of a passive aeration ditch (PAD

期刊论文

Numerical modeling and performance evaluation of passive convergence-permeable reactive barrier (PC-PRB

期刊论文

Investigation on sampling artifacts of particle associated PAHs using ozone denuder systems

Kai LIU, Fengkui DUAN, Kebin HE, Yongliang MA, Yuan CHENG

期刊论文

A sampling method based on URL clustering for fast web accessibility evaluation

Meng-ni ZHANG,Can WANG,Jia-jun BU,Zhi YU,Yu ZHOU,Chun CHEN

期刊论文

Parametric control of structural responses using an optimal passive tuned mass damper under stationary

Min-Ho CHEY, Jae-Ung KIM

期刊论文

Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault

Hamed HABIBI, Hamed RAHIMI NOHOOJI, Ian HOWARD

期刊论文

Dilution sampling and analysis of particulate matter in biomass-derived syngas

Xiaoliang WANG, Curtis ROBBINS, S. Kent HOEKMAN, Judith C. CHOW, John G. WATSON, Dennis SCHUETZLE

期刊论文

Recent developments in passive interconnected vehicle suspension

Wade A. SMITH, Nong ZHANG,

期刊论文

Moving target detection in the cepstrum domain for passive coherent location (PCL) radar

Ji-chuan LI,Xiao-de LU,Hui ZHANG,Peng-cheng YANG,Yu LIU,Mao-sheng XIANG

期刊论文

A state-of-the-art review of solar passive building system for heating or cooling purpose

Arun Kumar NANDA,C K PANIGRAHI

期刊论文

Unified methodology for site-characterization and sampling of highway runoff

Jy S. WU, Craig J. ALLAN,

期刊论文

单站无源定位可观测性评述

邓新蒲

期刊论文