Search | Engineering

订阅投稿

首页学术期刊学术焦点学术视频工程成就工程前沿联系我们 English

资源类型

期刊论文 62

年份

2022 5

2021 7

2020 7

2019 5

2018 7

2017 2

2016 5

2015 4

2014 2

2013 5

2012 1

2011 1

2010 1

2009 2

2007 1

2006 1

2004 1

2002 1

2000 1

展开︾

关键词

L1₀FePt 1

AQAM 1

两弹一星 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

亚三角洲 1

交换 1

京津冀城市群 1

人为地形变化 1

共同李雅普诺夫函数 1

共赢博弈 1

农用地 1

分布式结构 1

切换拓扑 1

双目标渐进法 1

反演非对称 1

反馈回路 1

可调多波长选择路由器 1

垂直各向异性 1

多智能体系统 1

展开︾

检索范围：

排序：展示方式：

An improved delta-star switching scheme for reactive power saving in three-phase induction motors

P. RAJA,N. KUMARESAN,M. SUBBIAH

《能源前沿（英文）》 2014年第8卷第3期页码 364-370 doi: 10.1007/s11708-014-0324-8

摘要： It is proposed that a capacitor can be connected permanently across each phase winding of a three-phase induction motor along with the conventional delta-star switching, for further saving in VARh at reduced loads on the motor. The method of choosing a suitable value for the capacitor and the criteria to be adopted for calculating the power output at which the star to delta switching is to be made are also explained. The experimental results on a 3-phase, 4-pole, 415 V, 50 Hz, 3.3 kW induction motor verify the advantages in adding the capacitor to the phase winding of the motor. Compared to using only a single delta connected stator winding or a delta-star switching, the advantages of the proposed addition of a capacitor, are also demonstrated through a case study conducted on a 400 V, 250 kW motor. Any further improvement in grid side power factor can be achieved by employing a static synchronous compensator (STATCOM) of reduced VAR rating.

关键词： delta-star switching induction motor power factor steady-state analysis

HTML PDF 收藏

Stress induced polarization switching and coupled hysteretic dynamics in ferroelectric materials

Linxiang WANG, Roderick MELNIK, Fuzai LV

《机械工程前沿（英文）》 2011年第6卷第3期页码 287-291 doi: 10.1007/s11465-011-0230-2

摘要：

The dynamic responses of ferroelectric materials upon external mechanical and electrical stimulations are inherently nonlinear and coupled. In the current paper, a macroscopic differential model is constructed for the coupled hysteretic dynamics via modeling the orientation switching induced in the materials. A non-convex potential energy is constructed with both mechanic and electric field contributions. The governing equations are formulated as nonlinear ordinary differential equations by employing the Euler-Lagrange equation, and can be easily recast into a state space form. Hysteresis loops associated with stress induced polarization switching and butterfly-shaped behavior in ferroelectric materials are also successfully captured. The effects of mechanical loadings on the electrically induced switching are numerically investigated, as well as the mechanically-induced switching with various bias electric fields.

关键词： differential model state space electromechanical switching butterfly effects hysteresis

HTML PDF 收藏

Long-term trends of fine particulate matter and chemical composition in the Pearl River Delta Economic

Xuemei WANG,Weihua CHEN,Duohong CHEN,Zhiyong WU,Qi Fan

《环境科学与工程前沿（英文）》 2016年第10卷第1期页码 53-62 doi: 10.1007/s11783-014-0728-z

摘要： Understanding the trends in PM levels is essential for formulating clean air plans. This paper analyzes PM data from various published sources for the years 2000 to 2010 in the Pearl River Delta Economic Zone (PRDEZ). The long-term variation in PM mass concentration is analyzed. Results show that PM , organic carbon (OC), elemental carbon (EC), and show a similar trend, increasing before 2005 and then decreasing slightly. The annual average PM concentration ranges from 49.1 μg·m in 2000 to 64.3 μg·m in 2010, with a peak of 84.1 μg·m in 2004. None of these 11 years meets the new National Ambient Air Quality standard (NAAQS) for PM (35 μg·m ). Overall average concentrations of OC, EC, and are 13.0, 6.5, and 11.8 μg·m , respectively. and respectively have concentrations of 1.5 μg·m and 2.9 μg·m in 2000 and 6.4 μg·m and 5.3 μg·m in 2010, with a statistically significant average annual trend of+ 0.2 μg·m ·yr and+ 0.1 μg·m ·yr . In certain geographic regions, OC and EC contribute most of the PM , while in other regions secondary water-soluble ions are more important. In general, OC and are the dominant components of PM , contributing 20.6% and 18.6%, respectively. These results provide, for the first time, a better understanding of the long-term PM characteristics and trends, on a species-by-species basis, in the PRDEZ. The results indicate that PM abatement needs to prioritize secondary species.

关键词： long-term trends fine particulate matter chemical components Pearl River Delta Economic Zone (PRDEZ)

HTML PDF 收藏

Experimental investigation of a novel micro gas turbine with flexible switching function for distributed

Xiaojing LV, Weilun ZENG, Xiaoyi DING, Yiwu WENG, Shilie WENG

《能源前沿（英文）》 2020年第14卷第4期页码 790-800 doi: 10.1007/s11708-020-0691-2

摘要： Micro gas turbine (MGT) is widely used in small-scale distributed power systems because of its low emissions and fuel flexibility. However, the under-utilization of its exhaust heat and the low electric efficiency are the main bottlenecks that restrict its application. Additionally, the flexible switching between the power generated by the MGT and the power grid is also a key factor for keeping the secure operation of a distributed power station. Therefore, this paper conducted some experimental investigations of a 30 kW MGT to provide reference solutions for the above issues. This MGT is located at Shanghai Jiao Tong University (SJTU), which is designed by the Gas Turbine Research Institute of SJTU, and is manufactured by a turbo-machinery factory in Chongqing, China. The demonstration prototype is mainly composed of a single stage centrifugal compressor, a radial turbine, a combustor, a high-speed permanent magnet generator, and a control system. The results show that the MGT can achieve steady operation at a low rotational speed from 10000 r/min to 34000 r/min in the case of using oil lubricated bearings, which can greatly reduce the economic cost compared with the use of air bearings. At the same time, the ignition success rate of combustion chamber (CC) reaches 98% at a low rotational speed, and a wide range of stable combustion area can be obtained, because of the novel design method of combustor by referencing the way applied in an axial flow aero-engine. The MGT generating set can achieve functions, such as starting up, ignition, stable operation, loaded operation, grid-connection and stopping. This system also can realize flexibly switching from the start motor mode to the generator mode, and from grid-connected mode to off-grid mode, because the innovative multi-state switching control system is adopted. The above research work can make our state master independent intellectual property rights of micro gas turbine, rather than continue to be subject to the technological monopoly of the developed states, which can provide theoretical and experimental support for the industrialization of MGT in China.

关键词： gas turbine flexible switching system control system distributed power system emission test

HTML PDF 收藏

Toward deep impacts of BIM on education

Žiga TURK, Andreja ISTENIČ STARČIČ

《工程管理前沿（英文）》 2020年第7卷第1期页码 81-88 doi: 10.1007/s42524-019-0035-2

摘要： Building information models (BIM) provide a way to represent buildings and communicate about them. In teaching engineering, we also need representations of buildings and are communicating knowledge about them. While teaching engineering we refer to the very same real-world objects that have an explicit conceptualization in BIM. This explicit conceptualization did not exist in the age when design communication relied on drawings and documents. The question that this paper asks is this: due to BIM, communication in the industry has changed. Should communication of engineering knowledge – teaching – change as well and how? While much has been written about teaching BIM and incorporating BIM into the curricula, this paper is exploring the general impact of BIM on engineering education. It grounds earlier work (Turk, 2018) on insights from pedagogy. Five scenarios of the interplay between BIM-influenced engineering communication and teaching are presented. The paper argues that ignoring BIM may create a cognitive dissonance between academic learning and industrial work. We are finding that the impact of BIM is twofold: vertically there is a need to establish a reference between knowledge concepts (in teaching building) and information objects (in building information models). Horizontally BIM is an integration technology that allows for a more holistic design and planning. Both the language of individual courses as well as cross references and synergies among courses should change. A “T” style structure of the courses around BIM is proposed as a basis for integrated curriculum. Pedagogical approaches based on deep learning, model based learning and project based learning are suggested.

关键词： engineering education building information modelling engineering communication curriculum development

HTML PDF 收藏

Energy internet in the Yangtze River Delta: opportunities, challenges, and suggestions

Zheng YAN, Jiayi HU

《能源前沿（英文）》 2018年第12卷第4期页码 484-492 doi: 10.1007/s11708-018-0600-0

摘要：

Energy internet is an Internet of Things (IoT) based network, which combines the multi-energy flows and the information flows. In this review, the opportunities and the challenges posed to developing energy internet in the Yangtze River Delta are analyzed concerning detailed analysis of its advantages in various aspects and problems of its energy systems. Then the framework of energy internet in the Yangtze River Delta is constructed, according to which specific suggestions are also provided. This review is dedicated to helping the policy makers to draw the roadmap of future-oriented energy internet.

关键词： energy internet opportunities challenges suggestions the Yangtze River Delta

HTML PDF 收藏

“两弹一星”事业对中国社会发展的影响

苗东升

《中国工程科学》 2004年第6卷第7期页码 14-20

摘要：

从五个方面回顾和讨论了“两弹一星”及其后续发展航天工程对中国的巨大历史作用：为国家建设获得和平的国际环境提供必要保障；占领高新科技的世纪性制高点；日益凸显重大的经济和社会意义；培育宝贵的民族精神；获得建立合理的国际新秩序所必须的大国地位。

关键词：两弹一星航天科技开发太空共赢博弈

HTML PDF 收藏

A novel soft-switching twin arc pulse MAG welding inverter

WANG Zhenmin, XUE Jiaxiang, WANG Fuguang, HUANG Shisheng

《机械工程前沿（英文）》 2007年第2卷第2期页码 224-227 doi: 10.1007/s11465-007-0039-1

摘要： The high-speed double wire pulse metal gas arc (MAG) welding process possesses advantages of automation and high efficiency and quality. Thus, it attracts much more attention nowadays. To meet the requirements of the double wire pulse MAG welding process, a novel double wire pulse MAG welding inverter integrated with technologies, such as soft-switching, double closed loop control, and synchronic control, is produced. A complete performance test was done for the pulsed MAG welding power supply by using a computer testing platform. The results of the experiment indicate that the novel welding inverter has an excellent performance both in the dynamic and the static characteristics. Also, the synchronic control between the master inverter and the slave inverter is reliable.

关键词： high-speed control computer experiment indicate platform

HTML PDF 收藏

attribution for mercury deposition with an updated atmospheric mercury emission inventory in the Pearl River Delta

Jiajun Liu, Long Wang, Yun Zhu, Che-Jen Lin, Carey Jang, Shuxiao Wang, Jia Xing, Bin Yu, Hui Xu, Yuzhou Pan

《环境科学与工程前沿（英文）》 2019年第13卷第1期 doi: 10.1007/s11783-019-1087-6

摘要：

Estimated anthropogenic Hg emission was 11.9 tons in Pearl River Delta for 2014.

Quantifying contributions of emission sources helps to provide control strategies.

More attentions should be paid to Hg deposition around the large point sources.

Power plant, industrial source and waste incinerator were priorities for control.

A coordinated regional Hg emission control was important for controlling pollution.

关键词： Emission inventory Mercury deposition Pearl River Delta (PRD) Source attribution Control strategy

HTML PDF 收藏

Photochemical indicators of ozone sensitivity: application in the Pearl River Delta, China

Lyumeng Ye,Xuemei Wang,Shaofeng Fan,Weihua Chen,Ming Chang,Shengzhen Zhou,Zhiyong Wu,Qi Fan

《环境科学与工程前沿（英文）》 2016年第10卷第6期 doi: 10.1007/s11783-016-0887-1

摘要： The distribution of NO - and VOC-sensitive regimes in the PRD are identified. The effectiveness of six popular chemical indicators for discriminating O sensitivity regimes is evaluated. Threshold levels for HCHO/NO , H O /HNO , O /NO , O /NO , O /HNO were derived and verified. The indicators H O /HNO and H O /NO performed best and maintained relatively stable threshold levels. Surface O production has a highly nonlinear relationship with its precursors. The spatial and temporal heterogeneity of O -NO -VOC-sensitivity regimes complicates the control- decision making. In this paper, the indicator method was used to establish the relationship between O sensitivity and assessment indicators. Six popular ratios indicating ozone-precursor sensitivity, HCHO/NO , H O /HNO , O /NO , O /NO , O /HNO , and H O /NO , were evaluated based on the distribution of NO - and VOC-sensitive regimes. WRF-Chem was used to study a serious ozone episode in fall over the Pearl River Delta (PRD). It was found that the south-west of the PRD is characterized by a VOC-sensitive regime, while its north-east is NO -sensitive, with a sharp transition area between the two regimes. All indicators produced good representations of the elevated ozone hours in the episode on 6 November 2009, with H O /HNO being the best indicator. The threshold sensitivity levels for HCHO/NO , H O /HNO , O /NO , O /NO , O /HNO , and H O /NO were estimated to be 0.41, 0.55, 10.2, 14.0, 19.1, and 0.38, respectively. Threshold intervals for the indicators H O /HNO , O /NO , O /NO , O /HNO , and H O /NO were able to identify more than 95% of VOC- and NO -sensitive grids. The ozone episode on 16 November 16 2008 was used to independently verify the results, and it was found that only H O /HNO and H O /NO were able to differentiate the ozone sensitivity regime well. Hence, these two ratios are suggested as the most appropriate indicators for identifying fall ozone sensitivity in the PRD. Since the species used for indicators have seasonal variation, the utility of those indicators for other seasons should be investigated in the future work.

关键词： Ozone Pearl River Delta (PRD) Sensitivity regime Photochemical indicator Threshold levels

HTML PDF 收藏

Space view of the decadal variation for typical air pollutants in the Pearl River Delta (PRD) region

Zifeng WANG, Min SHAO, Liangfu CHEN, Minghui TAO, Liuju ZHONG, Duohong CHEN, Meng FAN, Yang WANG, Xinhui WANG

《环境科学与工程前沿（英文）》 2016年第10卷第5期 doi: 10.1007/s11783-016-0853-y

摘要： Spatial and temporal trends of the typical pollutants in PRD viewed from space. Comparisons of the satellite retrievals with the collocated in situ data are given. Among different MCs, the control measures applied in PRD are the most effective. The unique HCHO trends imply significant contribution from the biogenic origins. The Pearl River Delta (PRD) is one of the most industrialized, urbanized and populated regions in China, and thus has been long suffering from severe air pollutions. Space data provide a unique perspective for investigating the atmospheric environment at a regional scale. By utilizing multiple satellite retrievals from 2005 to 2013, this study presented, for the first time, the spatial patterns and temporal trends of typical air pollutants over PRD and its vicinity. As viewed from space, aerosol optical depth (AOD), NO2 and SO2 all had their higher values at the central part of PRD, and showed clear descending gradients as moving to the outskirt of this region. As to the inter-annual variation, all these pollutants had decreasing trends in PRD during the study period, which generally agreed with the relevant in situ measurements. However, the satellite retrievals differed from ground measurements when addressing NO2 and SO2 in the vicinity of PRD. This work also provides the inter-comparison among PRD and three other metropolitan clusters in China: PRD had relatively high AOD, moderate NO2 and low SO2 levels, and it was the only region achieving the effective reduction of NO2 and SO2 during last decade. Unlike the previous three pollutants, HCHO observed by satellite showed very special patterns: it had a relatively homogeneous spatial distribution over both of PRD and its vicinity, and presented an opposite increasing trend from 2005 to 2010. Moreover, PRD had the highest HCHO level among all the metropolitan clusters, hinting a considerable contribution of biogenic origins of HCHO in PRD.

关键词： The Pearl River Delta (PRD) Satellite monitoring Regional air quality Long-term trend HCHO

HTML PDF 收藏

An artificial intelligence enhanced star identification algorithm

Hao Wang, Zhi-yuan Wang, Ben-dong Wang, Zhuo-qun Yu, Zhong-he Jin, John L. Crassidis,roger@zju.edu.cn

《信息与电子工程前沿（英文）》 2020年第21卷第11期页码 1535-1670 doi: 10.1631/FITEE.1900590

摘要： An artificial intelligence enhanced algorithm is proposed for s in mode. A model based on Vgg16 is used in the artificial intelligence algorithm to classify star images. The training dataset is constructed to achieve the networks’ optimal performance. Simulation results show that the proposed algorithm is highly robust to many kinds of noise, including position noise, magnitude noise, false stars, and the tracker’s angular velocity. With a deep , the identification accuracy is maintained at 96% despite noise and interruptions, which is a significant improvement to traditional pyramid and grid algorithms.

关键词：星敏感器；姿态失锁；星图识别；卷积神经网络

HTML PDF 收藏

国内首台ATM交换机研制及其组网实践

雷振明

《中国工程科学》 2000年第2卷第2期页码 53-55

摘要：

国内首台ATM（异步转送方式）交换机BTC-9500的研制于1995年完成，并配合国内宽带试验网络的建设，进行了大量的组网试验、设计改进和发展工作。目前，该设备已经由国内最大的电信设备制造商之一——上海贝尔公司生产销售，并且用于装备中国电信宽带骨干网的全部核心节点。根据组网实践中发现的问题，提出了在同一个交换结构内同时实现ATM信元交换和IP数据报交换的方案，并在BTC-9500中予以实现，达到了大大节省设备、简化网络和提高网络速度的多重目的，将研究范围逐渐拓宽到更大的宽带通信领域，提出了对于新一代电信网络发展的一些看法。

关键词：通信交换异步转送方式（ATM）

HTML PDF 收藏

Gained switching-based fuzzy sliding mode control for a discrete-time underactuated robotic system with

Hui LI, Ruiqin LI, Jianwei ZHANG

《机械工程前沿（英文）》 2021年第16卷第2期页码 353-362 doi: 10.1007/s11465-020-0620-4

摘要： This study proposes a gained switching-based discrete-time sliding mode control method to address the chattering issue in disturbed discrete-time systems, which suffer from various unknown uncertainties. Through the new structure of the designed reaching law, the proposed method can effectively increase the convergence speed while guaranteeing chattering-free control. The performance of controlling underactuated robotic systems can be further improved by the adoption of fuzzy logic to perform adaptive online hyper-parameter tuning. In addition, an underactuated robotic system with uncertainties is studied to validate the effectiveness of the proposed reaching law. Results reveal the dynamic performance and robustness of the proposed reaching law in the studied system and prove the proposed method’s superiority over other state-of-the-art methods.

关键词： sliding-mode control robot control discrete-time uncertain systems fuzzy logic

HTML PDF 收藏

Neutralization against SARS-CoV-2 Delta/Omicron variants and B cell response after inactivated vaccination

《医学前沿（英文）》 doi: 10.1007/s11684-022-0954-x

摘要： Emerging SARS-CoV-2 variants have made COVID-19 convalescents susceptible to re-infection and have raised concern about the efficacy of inactivated vaccination in neutralization against emerging variants and antigen-specific B cell response. To this end, a study on a long-term cohort of 208 participants who have recovered from COVID-19 was conducted, and the participants were followed up at 3.3 (Visit 1), 9.2 (Visit 2), and 18.5 (Visit 3) months after SARS-CoV-2 infection. They were classified into three groups (no-vaccination (n = 54), one-dose (n = 62), and two-dose (n = 92) groups) on the basis of the administration of inactivated vaccination. The neutralizing antibody (NAb) titers against the wild-type virus continued to decrease in the no-vaccination group, but they rose significantly in the one-dose and two-dose groups, with the highest NAb titers being observed in the two-dose group at Visit 3. The NAb titers against the Delta variant for the no-vaccination, one-dose, and two-dose groups decreased by 3.3, 1.9, and 2.3 folds relative to the wild-type virus, respectively, and those against the Omicron variant decreased by 7.0, 4.0, and 3.8 folds, respectively. Similarly, the responses of SARS-CoV-2 RBD-specific B cells and memory B cells were boosted by the second vaccine dose. Results showed that the convalescents benefited from the administration of the inactivated vaccine (one or two doses), which enhanced neutralization against highly mutated SARS-CoV-2 variants and memory B cell responses. Two doses of inactivated vaccine among COVID-19 convalescents are therefore recommended for the prevention of the COVID-19 pandemic, and vaccination guidelines and policies need to be updated.

关键词： COVID-19 convalescent SARS-CoV-2 inactivated vaccination neutralizing antibody B cell response

HTML PDF 收藏

标题作者时间类型操作

An improved delta-star switching scheme for reactive power saving in three-phase induction motors

P. RAJA,N. KUMARESAN,M. SUBBIAH

期刊论文

Stress induced polarization switching and coupled hysteretic dynamics in ferroelectric materials

Linxiang WANG, Roderick MELNIK, Fuzai LV

期刊论文

Long-term trends of fine particulate matter and chemical composition in the Pearl River Delta Economic

Xuemei WANG,Weihua CHEN,Duohong CHEN,Zhiyong WU,Qi Fan

期刊论文

Experimental investigation of a novel micro gas turbine with flexible switching function for distributed

Xiaojing LV, Weilun ZENG, Xiaoyi DING, Yiwu WENG, Shilie WENG

期刊论文

Toward deep impacts of BIM on education

Žiga TURK, Andreja ISTENIČ STARČIČ

期刊论文

Energy internet in the Yangtze River Delta: opportunities, challenges, and suggestions

Zheng YAN, Jiayi HU

期刊论文

“两弹一星”事业对中国社会发展的影响

苗东升

期刊论文

A novel soft-switching twin arc pulse MAG welding inverter

WANG Zhenmin, XUE Jiaxiang, WANG Fuguang, HUANG Shisheng

期刊论文

attribution for mercury deposition with an updated atmospheric mercury emission inventory in the Pearl River Delta

Jiajun Liu, Long Wang, Yun Zhu, Che-Jen Lin, Carey Jang, Shuxiao Wang, Jia Xing, Bin Yu, Hui Xu, Yuzhou Pan

期刊论文

Photochemical indicators of ozone sensitivity: application in the Pearl River Delta, China

Lyumeng Ye,Xuemei Wang,Shaofeng Fan,Weihua Chen,Ming Chang,Shengzhen Zhou,Zhiyong Wu,Qi Fan

期刊论文

Space view of the decadal variation for typical air pollutants in the Pearl River Delta (PRD) region

Zifeng WANG, Min SHAO, Liangfu CHEN, Minghui TAO, Liuju ZHONG, Duohong CHEN, Meng FAN, Yang WANG, Xinhui WANG

期刊论文

An artificial intelligence enhanced star identification algorithm

Hao Wang, Zhi-yuan Wang, Ben-dong Wang, Zhuo-qun Yu, Zhong-he Jin, John L. Crassidis,roger@zju.edu.cn

期刊论文

国内首台ATM交换机研制及其组网实践

雷振明

期刊论文

Gained switching-based fuzzy sliding mode control for a discrete-time underactuated robotic system with

Hui LI, Ruiqin LI, Jianwei ZHANG

期刊论文

Neutralization against SARS-CoV-2 Delta/Omicron variants and B cell response after inactivated vaccination

期刊论文

关注我们