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Modelling of urban ambient N,N-dimethylformamide concentrations in a small-scale synthetic leather industrial zone

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第5期12卷 374-389页

作者： Yu-mei wei wei-li tian Ying-yue ZHENG Qing-yu ZHANG Lei JIANG Zu-cheng WU Department of Envtronmental Engineering Zhejiang University Hangzhou 310027 China Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control Hangzhou 311202 China

A method to model small-scale ambient concentrations of N, N-dimethylformamide (DMF) in a synthetic leather industrial zone was developed. Longwan, a district of Wenzhou City in Southeast China, was selected as the study area. DMF emissions at the synthetic leather industrial zone were inventoried, during 2007, and an AMS/EPA regulatory model (AERMOD) was used to simulate DMF concentrations using 10 000 100 m×100 m grids for the 2006 period. In 2007, actual DMF concentrations were recorded at seven DMF monitoring stations, and were compared with simulated results for the same timeframe. Simulated DMF concentrations were predicted to be in the range of 0.012-2.31 mg/m3, which is similar to the range of the monitored dataset results. A large majority (93%) of relative errors (REs) between simulated and monitored concentrations ranged from 0.48% to 189.4%. While DMF emissions within factories did not exceed the regulated emission limit, simulations indicated that, in 2006, 20% of the daily average ambient DMF concentrations exceeded this limit. This Modelling method could be applied in evaluating regional atmospheric environmental capacities and human exposure to DMF.

关键词： N N-dimethylformamide (DMF) Geographic information system (GIS) Emission inventory AERMOD Small-scale

Force-position collaborative optimization of rope-driven snake manipulator for capturing non-cooperative space targets

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Chinese Journal of Aeronautics 2024年第9期37卷 369-384页

作者： Xiaofeng li Jian tian Cheng wei Xibin CAO School of Astronautics Harbin Institute of TechnologyHarbin 150001China Beijing Instiuteof Spacecraft System Engineering China Academy of Space TechnolgyBeijing 100094Chia

With the rapid development of space activities,non-cooperative space targets increase swiftly,such as failed satellites and upper stages,threating normal spacecrafts *** there are some problems in the capture process,such as excessive collision and fast tumbling of targets,manipulator with redundant Degrees of Freedom(DOFs)can be used to improve the compliance and therefore solve these *** Rope-Driven Snake Manipulator(RDSM)is a combina-tion of hyper-redundant DOFs and better compliance,and therefore it is suitable for capturing *** this paper,a snake manipulator mechanism is designed,and the complete kinematic model and system dynamic model considering RDSM,target and contact is ***,to obtain the configuration of joint with hyper-redundant DOFs,an improved motion dexterity index is pro-posed as the joint motion optimization ***,the force-position collaborative optimization index is designed to adjust active stiffness,and the impedance control method based on the modified index is used to capture the space ***,the proposed force-position collaborative opti-mization method is verified by virtual prototype *** results demonstrate that based on the proposed method,the collision force is reduced by about 25%compared to normal impe-dance control,showing higher safety.

关键词： Capturing non-cooperative spacetargets Rope-driven snakemanipu-lator Force-position collaborative optimization Redundant degrees of free-dom Active stiffness adjustment

A novel interpretable multilevel wavelet decomposition deep network for actual heartbeat classification

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Science China(Technological Sciences) 2024年第6期67卷 1842-1854页

作者： JIN YanRui li ZhiYuan tian YuanYuan wei XiaoYang liU Chengliang School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240China

Arrhythmias may lead to sudden cardiac death if not detected and treated in time.A supraventricular premature beat(SPB)and premature ventricular contraction(PVC)are important categories of arrhythmia ***,deep learning methods have been applied to the PVC/SPB heartbeats ***,most researchers have focused on time-domain information of the electrocardiogram and there has been a lack of exploration of the interpretability of the *** this study,we design an interpretable and accurate PVC/SPB recognition algorithm,called the interpretable multilevel wavelet decomposition deep network(IMWDDN).Wavelet decomposition is introduced into the deep network and the squeeze and excitation(SE)-Residual block is designed for extracting time-domain and frequency-domain ***,inspired by the idea of residual learning,we construct a novel loss function for the constant updating of the multilevel wavelet decomposition ***,the IMWDDN is evaluated on the Third China Physiological Signal Challenge Dataset and the MIT-BIH Arrhythmia *** comparison results show IMWDDN has better detection performance with 98.51%accuracy and a 93.75%F1-macro on average,and its areas of concern are similar to those of an expert diagnosis to a certain ***,the IMWDDN has good application value in the clinical screening of PVC/SPB heartbeats.

关键词： actual heartbeat classification electrocardiogram interpretable deep network multilevel discrete wavelet decomposition layer SE-Residual block

Resource-saving scheduling scheme for centralized target tracking in multiple radar system under automatic blanket jamming

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Chinese Journal of Aeronautics 2024年第5期37卷 349-362页

作者： Zhengjie li Yujie wei Junwei XIE Haowei ZHANG Yu tian Air and Missile Defense College Air Force Engineering UniversityXi’an 710051China Air Force Xi’an Flying College Xi’an 710300China Air and Missile Defense Institute Air Force Research InstituteBeijing 100085China School of Economics and Management Beihang UniversityBeijing 100191China

This paper investigates the problem of Joint Radar Node Selection and Power Allocation(JRNSPA)in the Multiple Radar System(MRS)in the blanket jamming *** radar node independently tracks moving target and subsequently transmits the raw observation data to the fusion center,which formulates a centralized tracking network *** order to establish a practical blanket jamming environment,we suppose that each target carries the self-defense jammer which automatically implements blanket jamming to the radar nodes that exceed the preset interception ***,the Predicted Conditional Cramer-Rao Lower Bound(PC-CRLB)is derived and utilized as the tracking accuracy *** at ensuring both the tracking performance and the Low Probability of Intercept(LPI)performance,the resource-saving scheduling model is formulated to minimize the transmit power consumption while meeting the requirements of tracking ***,the Modified Zoutendijk Method Of Feasible Directions(MZMFD)-based two-stage solution technique is adopted to solve the formulated non-convex optimization *** results show the effectiveness of the proposed JRNSPA scheme.

关键词： Multiple Radar System(MRS) Centralized target tracking Resource scheduling Blanket jamming Low Probability of Intercept(LPI)

Impact of Mo/Ni alloying on microstructural modulation and low-temperature toughness of high-strength low-alloy steel

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Journal of Iron and Steel Research International 2024年第7期31卷 1746-1762页

作者： wei liu Hong-li Zhao Bing-xing Wang Yong tian State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

The high-strength low-alloy steel plates with varying Ni/Mo contents were manufactured using the thermos-mechanical control *** investigation was conducted to explore the effect of Ni/Mo microalloying on microstructure evolution and mechanical properties of the *** results revealed that the increase in Ni content from 1 to 2 wt.%reduced the transition temperature of ferrite and the growth range of ferritic grain was narrowed,which promoted grain *** optimized combination of grain size,high-angle grain boundaries(HAGBs),and martensite-austenite(M-A)islands parameter contributed to the excellent impact toughness of S1 steel at-100℃(impact absorbed energy of 218.2 J at-100℃).As the Mo increases from 0 to 2 wt.%,the matrix structure changes from multiphase structure to granular bainite,which increases the average effective grain size to~4.62 pm and reduces HAGBs proportion to~36.22%.With these changes,the low-temperature impact toughness of S3 steel is *** addition,based on the analysis of the characteristics of crack propagation path,it was found that M-A islands with low content(~2.21%)and small size(~1.76 pm)significantly retarded crack propagation,and the fracture model of M-A islands with different morphologies was further ***,correlation between behaviour of delamination and toughness was further analysed by observing delamination size and impact energy parameters.

关键词： High-strength low-alloy steel Microstructural regulation Ni addition Mo addition Crack propagation Low-temperature toughness

Steady-state multiscale CFD simulation of a circulating fluidized bed riser

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Particuology 2024年第10期93卷 54-64页

作者： Zhaojie Ke Yujie tian Fei li Bona Lu wei Wang State Key Laboratory of Mesoscience and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China

Compared to transient simulation,steady-state simulation of circulating fluidized bed risers is more efficient,but is also harder to perform due to the complex scale-dependency of dense gas-solid *** this work,steady-state computational fluid dynamics(CFD)simulation of a riser is performed using the steady energy-minimization multi-scale(EMMS)*** is found that the steady state corresponds to an extremely large scale of length and time,thus the grid size required in steady-state simulation is larger than that in transient *** time-averaged two-fluid model(TFM)coupled with the steady-state EMMS/1M drag model enables a good prediction of the S-shaped,axial solids distribution and the choking transition,whereas the two-phase turbulence and solids stress models are important in predicting the radially core-annular distribution of *** far as we know,this is the first time that one can predict the choking transition in a steady-state CFD *** improvement may need an EMMS modeling of the time-averaged solid stresses.

关键词： Fluidization Drag force Steady state Simulation Mesoscale

Mortality weighting-based method for aggregate urban air risk assessment

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第9期12卷 702-709页

作者： Qing-yu ZHANG Guo-jin SUN wei-li tian Yu-mei wei Si-mai FANG Jin-feng RUAN Guo-rong SHAN Yao SHI Department of Environmental Engineering Zhejiang University Hangzhou 310058 China Department of Chemical Engineering Zhejiang University Hangzhou 310027 China Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control Hangzhou 311202 China College of Information University of International Business and Economic Beijing 100029 China

This paper deals with a mortality-weighted synthetic evaluation （MWSE） method for evaluating urban air risk. Sulphur dioxide （SO2）, nitrogen oxide （NOx）, and particulate matter （PMl0） were used as pollution indices. The urban area of Hangzhou, China is divided into 756 grid cells, with a resolution of 1 km× 1 km, and is evaluated using the MWSE and the air quality index （AQI）, a widely-used method to evaluate ambient air quality and air risk. In an evaluation of one day in April 2004, the surface areas categorized as levels Ⅰ and Ⅲ, as defined by the integrated air risk evaluation, were 27.3% and 3.3% lower, respectively, than grades Ⅰ and Ⅲ defined by the AQI evaluation. Meanwhile, the areas classified as level Ⅱ or above level Ⅲ by the integrated air risk evaluation were 55.1% and 101. 1% higher, respectively, than grade Ⅱ or above grade Ⅲ when using the AQI evaluation. From this comparison, we find that the MWSE method is more sensitive than the AQI method. The AQI method uses a single index to assess integrated air quality and is therefore unable to evaluate integrated air risks due to multiple pollutants. The MWSE method overcomes this problem, providing improved accuracy in air risk assessment.

关键词： Integrated air risk Mortality-weighted synthetic evaluation (MWSE) Air quality index (AQI) Air pollution

Robust adaptive radar beamforming based on iterative training sample selection using kurtosis of generalized inner product statistics

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Journal of Systems Engineering and Electronics 2024年第1期35卷 24-30页

作者： tian Jing ZHANG wei School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Electromagnetic Space Security Chengdu 610036China

In engineering application,there is only one adaptive weights estimated by most of traditional early warning radars for adaptive interference suppression in a pulse reputation interval(PRI).Therefore,if the training samples used to calculate the weight vector does not contain the jamming,then the jamming cannot be removed by adaptive spatial *** the weight vector is constantly updated in the range dimension,the training data may contain target echo signals,resulting in signal cancellation *** cope with the situation that the training samples are contaminated by target signal,an iterative training sample selection method based on non-homogeneous detector(NHD)is proposed in this paper for updating the weight vector in entire range *** principle is presented,and the validity is proven by simulation results.

关键词： adaptive radar beamforming training sample selection non-homogeneous detector electronic jamming jamming suppression

用新型钕系催化剂体系催化合成超高顺式-1,4-聚丁二烯橡胶

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合成橡胶工业 2024年第2期47卷 93-98页

作者：张秀慧董静李旭李伟天王凤刘恒张学全青岛科技大学高分子科学与工程学院/橡塑材料与工程教育部重点实验室/山东省橡塑材料与工程重点实验室山东青岛266042 中国石油石油化工研究院兰州化工研究中心兰州730060 长春工业大学化学工程学院长春130012

采用由改性新癸酸钕[(m-Nd(vers)_(3))]为主催化剂、三异丁基铝为助催化剂和氯源组成的催化体系研究了丁二烯的聚合反应行为,考察了三异丁基铝用量、氯源结构、聚合反应温度、催化剂用量等因素对丁二烯聚合活性、顺式-1,4-结构选择性和... 详细信息

采用由改性新癸酸钕[(m-Nd(vers)_(3))]为主催化剂、三异丁基铝为助催化剂和氯源组成的催化体系研究了丁二烯的聚合反应行为,考察了三异丁基铝用量、氯源结构、聚合反应温度、催化剂用量等因素对丁二烯聚合活性、顺式-1,4-结构选择性和聚合物分子量及其分布的影响。结果表明,使用m-Nd(vers)3/三异丁基铝/倍半乙基氯化铝体系催化丁二烯聚合可得到具有较高催化活性、超高顺式-1,4-结构(最高摩尔分数可达99.2%)、高分子量(数均相对分子质量为1.19×10^(5)~4.12×10^(5))和窄分子量分布(多分散性指数小于2.5)的聚丁二烯。

关键词：改性稀土钕催化剂丁二烯顺式-1,4-结构聚合活性三异丁基铝倍半乙基氯化铝数均相对分子质量