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Mechatronic design of a novel linear compliant positioning stage with large travel range and high out-of-plane

Hua LIU, Xin XIE, Ruoyu TAN, Lianchao ZHANG, Dapeng FAN

《机械工程前沿（英文）》 2017年第12卷第2期页码 265-278 doi: 10.1007/s11465-017-0453-y

摘要：

Most of the XY positioning stages proposed in previous studies are mainly designed by considering only a single performance indicator of the stage. As a result, the other performance indicators are relatively weak. In this study, a 2-degree-of-freedom linear compliant positioning stage (LCPS) is developed by mechatronic design to balance the interacting performance indicators and realize the desired positioning stage. The key parameters and the coupling of the structure and actuators are completely considered in the design. The LCPS consists of four voice coil motors (VCMs), which are conformally designed for compactness, and six spatial leaf spring parallelograms. These parallelograms are serially connected for a large travel range and a high out-of-plane payload capacity. The mechatronic model is established by matrix structural analysis for structural modeling and by Kirchhoff’s law for the VCMs. The sensitivities of the key parameters are analyzed, and the design parameters are subsequently determined. The analytical model of the stage is confirmed by experiments. The stage has a travel range of 4.4 mm× 7.0 mm and a 0.16% area ratio of workspace to the outer dimension of the stage. The values of these performance indicators are greater than those of any existing stage reported in the literature. The closed-loop bandwidth is 9.5 Hz in both working directions. The stage can track a circular trajectory with a radius of 1.5 mm, with 40 mm error and a resolution of lower than 3 mm. The results of payload tests indicate that the stage has at least 20 kg out-of-plane payload capacity.

关键词： mechatronic design linear compliant positioning stage large travel range high out-of-plane payload capacity spatial parallelogram voice coil motor sensitivity analysis

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Understanding network travel time reliability with on-demand ride service data

Xiqun (Michael) CHEN, Xiaowei CHEN, Hongyu ZHENG, Chuqiao CHEN

《工程管理前沿（英文）》 2017年第4卷第4期页码 388-398 doi: 10.15302/J-FEM-2017046

摘要： Travel time reliability is of increasing importance for travelers, shippers, and transportation managers because traffic congestion has become worse in major urban areas in recent years. To better evaluate the urban network-wide travel time reliability, five indices based on the emerging on-demand ride service data are proposed: network free flow time rate (NFFTR), network travel time rate (NTTR), network planning time rate (NPTR), network buffer time rate (NBTR), and network buffer time rate index (NBTRI). These indices take into account the probability distribution of the travel time rate (i.e., travel time spent for the unit distance, in min/km) of each origin-destination (OD) pair in the road network. We use real-world data extracted from DiDi-Chuxing, which is the largest on-demand ride service platform in China. For demonstrative purposes, the network-wide travel time reliability of Beijing is analyzed in detail from two dimensions of time and space. The results show that the road network is more unreliable in AM/PM peaks than other time periods, and the most reliable time period is the early morning. Additionally, we can find that the central region is more unreliable than other regions of the city based on the spatial analysis results. The proposed network travel time reliability indices provide insights for the comprehensive evaluation of the road network traffic dynamics and day-to-day travel time variations.

关键词： network travel time reliability on-demand ride services travel time rate OD

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Appraisal of coastal recreational resources in Qingdao by travel cost method

Jingmei LI , Tieying LIU , Yuanyuan ZHANG , Lei LI ,

《环境科学与工程前沿（英文）》 2009年第3卷第3期页码 341-347 doi: 10.1007/s11783-009-0038-z

摘要： This paper serves to appraise the monetary cost of coastal recreational resources in Qingdao using the travel cost method (TCM), which is typically used in developed countries. The total revenue produced by Qingdao’s coastal recreational resources is about RMB 5.51×10 annually, based on questionnaires given at Qingdao’s major tourist destinations. These questionnaires establish correlation functions that factor in the number of tourists, travel expenses, etc. The data processing software named Eviews was used to determine the tourist demand regression curve and to calculate their residual and actual travel expenses. The results of this study can provide a scientific basis for applicable industries interested in development and management decision-making. Therefore, this study assesses the reasonable usage of coastal recreational resources.

关键词： coastal recreational resources travel cost method (TCM) regression analysis Qingdao China

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Range of ecological impact of highway construction in the Longitudinal Range-Gorge Region, China

Jie LIU, Fan CHEN, Haiqing GENG, Xinxin QIU, Binbin CAI,

《环境科学与工程前沿（英文）》 2010年第4卷第3期页码 349-360 doi: 10.1007/s11783-010-0027-2

摘要： The major features of different road sections were identified. Methods quantitatively determining the ecological impact of highway construction were discussed, and a demonstration was presented. The Dabao highway (from Dali to Baoshan) and the Sixiao highway (from Simao to Xiaomengyang) passing through the Longitudinal Range-Gorge Region were used as examples in this paper. For the normal road sections having no important species to protect, a method of ecosystem health assessment was introduced to calculate the overall range of the ecological impact of highway construction. For the road sections having plants or soils of interest, indexes were selected and the range of impact was determined using mathematical methods such as regression analysis and variance analysis. The range of impact on animal populations was also discussed in terms of the minimum living areas required by animal populations and the fragmentation caused by highway construction. The results indicate that the zones impacted by highway construction were composed of both regular and anomalous figures, the range of impacts for different landforms of the two sample highways were substantially different; highway construction had dramatic effects on roadside ecosystem health; the impact on soil factors of farmland was greater than 200 m, and the distance may exceed 1000 m when important large animals were considered.

关键词： range of impact quantitative analysis highway construction Longitudinal Range-Gorge Region

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导航卫星双向伪距时间同步

谭述森

《中国工程科学》 2006年第8卷第12期页码 70-74

摘要：

针对卫星导航系统时间同步需求，提出了导航卫星双向伪距时间同步的理论根据，并就4种基本同步方法（双向无线电伪距同步方法, 星地双向激光伪距同步方法,双向卫星中继无线电伪距同步方法, 双向地球站中继无线电伪距同步方法）与应用进行了分析，与目前国际导航卫星时间同步通用方法相比,具有精度高, 方法简单，设备负担轻特点。

关键词：导航卫星伪距时间同步

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Middle East respiratory syndrome coronavirus: current situation and travel-associated concerns

null

《医学前沿（英文）》 2016年第10卷第2期页码 111-119 doi: 10.1007/s11684-016-0446-y

摘要：

The emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 brought back memories of the occurrence of severe acute respiratory syndrome coronavirus (SARS-CoV) in 2002. More than 1500 MERS-CoV cases were recorded in 42 months with a case fatality rate (CFR) of 40%. Meanwhile, 8000 cases of SARS-CoV were confirmed in six months with a CFR of 10%. The clinical presentation of MERS-CoV ranges from mild and non-specific presentation to progressive and severe pneumonia. No predictive signs or symptoms exist to differentiate MERS-CoV from community-acquired pneumonia in hospitalized patients. An apparent heterogeneity was observed in transmission. Most MERS-CoV cases were secondary to large outbreaks in healthcare settings. These cases were secondary to community-acquired cases, which may also cause family outbreaks. Travel-associated MERS infection remains low. However, the virus exhibited a clear tendency to cause large outbreaks outside the Arabian Peninsula as exemplified by the outbreak in the Republic of Korea. In this review, we summarize the current knowledge about MERS-CoV and highlight travel-related issues.

关键词： coronavirus MERS Middle East respiratory syndrome

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Applying the multi-zone model in predicting the operating range of HCCI engines

Ming JIA, Maozhao XIE, Zhijun PENG,

《能源前沿（英文）》 2010年第4卷第3期页码 414-423 doi: 10.1007/s11708-010-0108-8

摘要： In this paper, a multi-zone model is developed to predict the operating range of homogeneous charge compression ignition (HCCI) engines. The boundaries of the operating range were determined by knock (presented by ringing intensity), partial burn (presented by combustion efficiency), and cycle-to-cycle variations (presented by the sensitivity of indicated mean effective pressure to initial temperature). By simulating an HCCI engine fueled with iso-octane, the knock and cycle-to-cycle variations predicted by the model showed satisfactory agreement with measurements made under different initial temperatures and equivalence ratios; the operating range was also well reproduced by the model. Furthermore, the model was applied to predict the operating range of the HCCI engine under different engine speeds by varying the intake temperatures and equivalence ratios. The potential to extend the operating range of the HCCI engine through two strategies, i.e., variable compression ratio and intake pressure boosting, was then investigated. Results indicate that the ignition point can be efficiently controlled by varying the compression ratio. A low load range can be extended by increasing the intake temperature while reducing the compression ratio. Higher intake temperatures and lower compression ratios can also extend the high load range. Boosting intake pressure is helpful in controlling the combustion of the HCCI engine, resulting in an extended high load range.

关键词： homogeneous charge compression ignition (HCCI) engine multi-zone operating range

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Accelerated degradation of orange G over a widepH range in the presence of FeVO

Xiaoxia Ou, Jianfang Yan, Fengjie Zhang, Chunhua Zhang

《环境科学与工程前沿（英文）》 2018年第12卷第1期 doi: 10.1007/s11783-018-1013-3

摘要： In this study, FeVO was prepared andused as Fenton-like catalyst to degrade orange G (OG) dye. The removalof OG in an aqueous solution containing 0.5 g·L FeVO and 15 mmol·L hydrogen peroxide at pH 7.0 reached 93.2%. Similar rates were achievedat pH 5.7 ( = 0.0471 min ), pH 7.0 ( = 0.0438 min ), and pH 7.7 ( = 0.0434 min ). The FeVO catalyst successfullyovercomes the problem faced in the heterogeneous Fenton process, i.e.,the narrow working pH range. The data for the removal of OG in FeVO systems containing H O conform to the Langmuir–Hinshelwood model ( = 0.9988),indicating that adsorption and surface reaction are the two basicmechanisms for OG removal in the FeVO –H O system. Furthermore, the irradiationof FeVO by visible light significantly increasesthe degradation rate of OG, which is attributed to the enhanced ratesof the iron cycles and vanadium cycles.

关键词： Azo dye Degradation FeVO₄ Kinetics Advanced oxidation processes

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面向精密增材制造的大范围柔性伺服系统

Zhen Zhang, Peng Yan, Guangbo Hao

《工程（英文）》 2017年第3卷第5期页码 708-715 doi: 10.1016/J.ENG.2017.05.020

摘要：

本文主要介绍可用于微立体光固化（MSL）工艺的基于分布柔度簧片的大范围柔性纳米伺服系统的设计、开发和控制。作为这一高精度工艺的使能技术，本文设计了一种兼具毫米级运动行程和纳米级运动精度的紧凑型台式柔性纳米运动系统。由于在运行中无需装配和维护，这种柔性运动系统非常适合苛刻的操作条件。从机械设计的角度来看，镜像对称布局和适当的冗余约束对于抑制寄生运动至关重要。本文对此系统进行了详细的有限元分析（FEA），分析结果表面系统具有满意的机械特征。通过纳米运动系统的动力学模型辨识，本文设计了实时控制策略，并将其应用在一体加工的原型系统中。实验验证了面向MSL 工艺过程的轨迹跟踪性能。所提出的纳米伺服运动系统具有毫米级的工作范围，圆轨迹跟踪误差约为80 nm（均方根值）。

关键词：精密增材制造微立体光固化纳米定位分布柔度簧片

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超声速客机计划再次登上历史舞台

Sean O’Neill

《工程（英文）》 2022年第10卷第3期页码 1-3 doi: 10.1016/j.eng.2022.01.004

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Future urban transport management

《工程管理前沿（英文）》页码 534-539 doi: 10.1007/s42524-023-0255-3

摘要： The incorporation of disruptive innovations into the transportation industry will inevitably cause major upheavals in the transportation sector. However, existing research lacks systematic theories and methodologies to represent the underlying characteristics of future urban transport systems. Furthermore, emerging modes in urban mobility have not been sufficiently studied. The National Natural Science Foundation of China (NSFC) officially approved the Basic Science Center project titled “Future Urban Transport Management” in 2022. The project members include leading scientists and engineers from Beijing Jiaotong University, Beihang University, and Beijing Transport Institute. Based on a wide range of previous projects by the consortium on urban mobility and sustainable cities, this project will encompass transdisciplinary and interdisciplinary research to explore critical issues affecting future urban traffic management. It aims to develop fundamental theories and methods based on social and technological developments in the near future and explores innovative solutions to implement alongside these emerging developments in urban mobility.

关键词： future urban transport management travel behavior characteristics transportation operations transportation emergency management transportation decision intelligence

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Kd-tree and quad-tree decompositions for declustering of 2D range queries over uncertain space

Ahmet SAYAR,Süleyman EKEN,Okan ÖZTÜRK

《信息与电子工程前沿（英文）》 2015年第16卷第2期页码 98-108 doi: 10.1631/FITEE.1400165

摘要： We present a study to show the possibility of using two well-known space partitioning and indexing techniques, kd trees and quad trees, in declustering applications to increase input/output (I/O) parallelization and reduce spatial data processing times. This parallelization enables time-consuming computational geometry algorithms to be applied efficiently to big spatial data rendering and querying. The key challenge is how to balance the spatial processing load across a large number of worker nodes, given significant performance heterogeneity in nodes and processing skews in the workload.

关键词： Kd tree Quad tree Space partitioning Spatial indexing Range queries Query optimization

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近程毫米波合成孔径辐射计被动测距原理

王本庆,李兴国

《中国工程科学》 2010年第12卷第3期页码 95-99

摘要：

毫米波合成孔径技术利用了物体自身辐射电磁波的相位信息，采用很少阵元就能实现实时成像，但目前合成孔径技术只是限于亮温成像，缺少了目标的距离信息，这对于目标探测与识别很不利。提出在近程条件下合成孔径被动测距原理和相应的双正交傅立叶变换算法，并给出了近程距离分辨率公式，近程成像的特点是成像公式中存在二次相位因子，而且距离分辨率和距离的平方成反比。毫米波合成孔径被动成像可以同时得到物体辐射的亮温分布和距离分布，能够有效克服离焦引起的图像模糊，对图像的反降晰和目标识别具有重要意义。

关键词：毫米波辐射计合成孔径近程成像被动测距 BFT

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An experimental study for optimization of high range water reducing superplasticizer in self compacting

Rahul DUBEY, Pardeep KUMAR

《结构与土木工程前沿（英文）》 2013年第7卷第1期页码 62-71 doi: 10.1007/s11709-013-0192-z

摘要： Concrete is extensively used construction material in the infrastructure development industry. With increase in technical knowhow, the need of research for high performance concretes such as self-compacting concrete (SCC) has increased in the last decade. The adaptability of SCC is due to its fluidic behavior in fresh state. However, to develop SCC using indigenous materials, the lack of standardized mix design procedures is the biggest impediment. Although with the advent of chemical admixtures, it is possible to achieve concrete with high fluidity, but at the same time durability issues require more attention. To have these fresh state properties SCC mixes are typically designed with high powder contents, and chemical admixtures. Proportioning and optimization of these materials is a key issue in the mix design of SCC. This paper focuses mainly on experimental study to optimize dosages of superplasticizer for mortar of SCC and then in concrete mixture itself.

关键词： self-compacting concrete (SCC) fresh properties superplasticizer optimization compressive strength