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A modified pulse charging method for lithium-ion batteries by considering stress evolution, chargingtime and capacity utilization

Yanfei ZHAO, Bo LU, Yicheng SONG, Junqian ZHANG

《结构与土木工程前沿（英文）》 2019年第13卷第2期页码 294-302 doi: 10.1007/s11709-018-0460-z

摘要： The stress evolution, total charging time and capacity utilization of pulse charging (PC) method are investigated in this paper. It is found that compared to the conventional constant current (CC) charging method, the PC method can accelerate the charging process but will inevitably cause an increase in stress and a decrease in capacity. The charging speed for PC method can be estimated by the mean current. By introducing stress control, a modified PC method called the PCCC method, which starts with a PC operation followed by a CC operation, is proposed. The PCCC method not only can accelerate charging process but also can avoid the stress raising and capacity loss occurring in the PC method. Furthermore, the optimal pulsed current density and switch time in the PCCC method is also discussed.

关键词： fast charging method pulse charging stress evolution charging time capacity utilization

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Non-invasive continuous blood pressure monitoring: a review of current applications

null

《医学前沿（英文）》 2013年第7卷第1期页码 91-101 doi: 10.1007/s11684-013-0239-5

摘要：

Blood pressure monitoring has come a long way from the initial observations made by Reverend Hales in the 18th century. There are none that deny the importance of monitoring perioperative blood pressure; however, the limited ability of the current prevalent technology (oscillometric blood pressure monitoring) to offer continuous blood pressure measurements leaves room for improvement. Invasive monitoring is able to detect beat-to-beat blood pressure measurement, but the risks inherent to the procedure make it unsuitable for routine use except when this risk is outweighed by the benefits. This review focuses on the discoveries which have led up to the current blood pressure monitoring technologies, and especially the creation of those offering non-invasive but continuous blood pressure monitoring capabilities, including their methods of measurement and limitations.

关键词： non-invasive blood pressure monitoring continuous blood pressure monitoring invasive blood pressure monitoring Riva-Rocci technique oscillometric Pe?áz technique arterial tonometry pulse transit time

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Performance-based seismic assessment of a historical masonry arch bridge: Effect of pulse-like excitations

《结构与土木工程前沿（英文）》页码 855-869 doi: 10.1007/s11709-023-0972-z

摘要： Seismic analysis of historical masonry bridges is important for authorities in all countries hosting such cultural heritage assets. The masonry arch bridge investigated in this study was built during the Roman period and is on the island of Rhodes, in Greece. Fifteen seismic records were considered and categorized as far-field, pulse-like near-field, and non-pulse-like near-field. The earthquake excitations were scaled to a target spectrum, and nonlinear time-history analyses were performed in the transverse direction. The performance levels were introduced based on the pushover curve, and the post-earthquake damage state of the bridge was examined. According to the results, pulse-like near-field events are more damaging than non-pulse-like near-field ground motions. Additionally the bridge is more vulnerable to far-field excitations than near-field events. Furthermore, the structure will suffer extensive post-earthquake damage and must be retrofitted.

关键词： masonry arch bridges seismic behavior modal properties pulse-like records nonlinear time history analysis

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System and prospects of China’s intercity rail transit technology

Ming GONG

《机械工程前沿（英文）》 2018年第13卷第2期页码 323-328 doi: 10.1007/s11465-018-0463-4

摘要：

City clusters and metropolitan areas in China are flourishing in the midst of the deepening urbanization in the country, thereby resulting in the emergence of intercity rail transit. Intercity railways connect mainline and urban railways for an integrated regional transportation system that underpins and leads the development of city clusters and metropolitan areas. This study explores the development mode and service characteristics of intercity rail transit, as well as proposes overviews on this system and prospects of its future technology in China.

关键词： intercity rail transit city cluster technical demand technology system

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Coupling analysis of passenger and train flows for a large-scale urban rail transit system

《工程管理前沿（英文）》 2023年第10卷第2期页码 250-261 doi: 10.1007/s42524-021-0180-2

摘要： Coupling analysis of passenger and train flows is an important approach in evaluating and optimizing the operation efficiency of large-scale urban rail transit (URT) systems. This study proposes a passenger–train interaction simulation approach to determine the coupling relationship between passenger and train flows. On the bases of time-varying origin–destination demand, train timetable, and network topology, the proposed approach can restore passenger behaviors in URT systems. Upstream priority, queuing process with first-in-first-serve principle, and capacity constraints are considered in the proposed simulation mechanism. This approach can also obtain each passenger’s complete travel chain, which can be used to analyze (including but not limited to) various indicators discussed in this research to effectively support train schedule optimization and capacity evaluation for urban rail managers. Lastly, the proposed model and its potential application are demonstrated via numerical experiments using real-world data from the Beijing URT system (i.e., rail network with the world’s highest passenger ridership).

关键词： urban rail transit coupling analysis passenger–train interaction large-scale simulation

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Esophageal pulse oximetry is more accurate and detects hypoxemia earlier than conventional pulse oximetry

null

《医学前沿（英文）》 2012年第6卷第4期页码 406-410 doi: 10.1007/s11684-012-0217-3

摘要：

The esophagus is perfused directly by prominent arteries and may provide a more consistent tissue source for pulse oximetry. The goal of this study was to evaluate the sensitivity and accuracy of an esophageal pulse oximetry probe on patients during controlled hypoxemia in comparison to measurements obtained with conventional pulse oximetry (SpulseO₂). Forty-five ASA I–II adult patients were included in this prospective observational study. Nellcor digital oximetric probes were placed on finger tips for SpulseO₂ before anesthesia. After tracheal intubation, an esophageal probe was placed in the lower segment of the esophagus for esophageal oximetric monitoring (SoesO₂). All patients were disconnected from the breathing circuit to establish a controlled hypoxemia, and were re-connected to the breathing circuit and ventilated with 100% oxygen immediately when SoesO₂ dropped to 90%. Matched SoesO₂ and SpulseO₂ readings were recorded when SoesO₂measurements were at 100%, 95%, 90% and the lowest reading. The time for SoesO₂ and SpulseO₂ to drop from 100% to 95%, 90% and return to 100% was recorded. Oxygen saturation from arterial blood samples (SartO₂) was also measured at each time point respectively. The linear correlation coefficient of the regression analysis between SartO₂ and SoesO₂ was 0.954. The mean±2SD of the difference was 0.3%±4.3% for SoesO₂vs. SartO₂ and 6.8%±5.6% for SpulseO₂vs. SartO₂ (P<0.001). The 95% confidence interval for the absolute difference between SoesO₂ and SartO₂ was 0.3% to 0.7% and 6.2% to 7.4% between SpulseO₂ and SartO₂. The time to reach 90% saturation measured with SoesO₂ was approximately 94 seconds earlier than the SpulseO₂ (P<0.001). In conclusion, SoesO₂ is more accurate and enables earlier detection of hypoxemia when compared to conventional pulse oximetry during hypoxemia for patients undergoing general anesthesia.

关键词： esophageal pulse oximetry conventional pulse oximetry hypoxemia

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Study of Sustainable Urban Rail Transit Development Model in China

Wen-wu Yang

《工程管理前沿（英文）》 2014年第1卷第2期页码 195-201 doi: 10.15302/J-FEM-2014026

摘要： As the grand urbanization rapidly progresses in China, Chinese government launches a magnificent urban rail transit development plan as the key part of the preferential public transportation strategy. It is very necessary to establish a viable public private partnership model for urban rail construction. The philosophy of transit-oriented-development （TOD） is discussed in this study by reviewing Hong Kong Railway+ Property development model which is proved very successful in mass transit rail development in Hong Kong. This paper examines current practice of urban transit as of conventional public transport infrastructure in China and looks into ways of getting over the bureaucratic and technologic hurdles in order to generating synergy value and opportunity of rail oriented urban development. Taking the TOD and public-private-partnership (PPP) study of Shenzhen metro line 6 as an example, the sustainable urban rail development model is introduced and elaborated. It concludes that the sustainable urban rail transit shall be able to energize the great potential of rail and urban development at macro, meso and micro levels, through effective integration of administration and technology resources, and generation of win-win scenarios among government, metro company, people and stakeholders.

关键词： urban rail transit Railway+ Property(R+P) sustainability transit oriented development private public partnership

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Development of New Modality Municipal Public Transportation for Guangzhou—Group Rapid Transit System

Ru-jiang Zhao,Wung Hee Moh

《工程管理前沿（英文）》 2015年第2卷第4期页码 378-390 doi: 10.15302/J-FEM-2015061

摘要： As one of the primary business centers of China, Guangzhou has been undergoing rapid growth and expansion. Over the past decade, the Guangzhou Municipality Government has significantly upgraded its transport infrastructure, especially with the highly beneficial expansion of its Subway Mass Rapid Transit (MRT) system. Positive steps have also been taken to continue planning the construction of new roads, a Bus Rapid Transit (BRT) system and other transportation facilities. Further administrative and regulatory measures have also been implemented to control the situation, such as the banning of motorcycles from the central city area and the limitation of new automobile registrations. However, Guangzhou continues to face serious challenges of traffic congestion in and around the city center owing to further intensification of its population with economic growth. The need to ease Guangzhou’s stretched public transportation resources, and at the same time to support the realization of its “Eastward Advance” strategy, presents a unique challenge and opportunity to develop an advanced high-efficiency public transportation modality for Guangzhou, viz. the Group Rapid Transit (GRT) involving the use of automation-guided (driverless) smart-vehicles. This paper outlines the PRT/GRT (PRT: Personal Rapid Transit) smart-vehicle modality and also puts forth a proposal of Guangzhou’s first GRT route as the city’s first dedicated transportation link to the scenic landscape of the Eastern Tourism Zone. This GRT route will help in diffusing the city’s traffic congestion as well as support the effectuation of Guangzhou’s “Eastern Expansion” strategy, supplementing the ongoing expansion of the Guangzhou Municipality’s subway MRT networks.

关键词： public transportation system innovative city transportation Subway Mass Rapid Transit (MRT) Bus Rapid Transit (BRT) Group Rapid Transit (GRT) Personal Rapid Transit (PRT)

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Energy-saving operation approaches for urban rail transit systems

Ziyou GAO, Lixing YANG

《工程管理前沿（英文）》 2019年第6卷第2期页码 139-151 doi: 10.1007/s42524-019-0030-7

摘要： With the accelerated urbanization in China, passenger demand has dramatically increased in large cities, and traffic congestion has become serious in recent years. Developing public urban rail transit systems is an indispensable approach to overcome these problems. However, the high energy consumption of daily operations is an emerging issue due to increased rail transit networks and passenger demands. Thus, reducing the energy consumption and operational cost by using advanced optimization methodologies is an urgent task for operation managers. This work systematically introduces energy-saving approaches for urban rail transit systems in three aspects, namely, train speed profile optimization, utilization of regenerative energy, and integrated optimization of train timetable and speed profile. Future research directions in this field are also proposed to meet increasing passenger demands and network-based urban rail transit systems.

关键词： urban rail transit energy saving speed profile optimization regenerative energy train timetable

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Dynamic analysis of rail transit elevated bridge with ladder track

He XIA, Yushu DENG, Yongwei ZOU, Guido DE ROECK, Geert DEGRANDE

《结构与土木工程前沿（英文）》 2009年第3卷第1期页码 2-8 doi: 10.1007/s11709-009-0001-x

摘要： In this paper, a dynamic analysis model of an elevated bridge with ladder tracks under moving train load is established. The whole process of a train running through an elevated bridge at different speeds is simulated. The dynamic responses of the elevated bridge with ladder track and the running safety and comfort index of train vehicles are evaluated. Compared with the dynamic responses of an elevated bridge with ordinary non-ballasted slab track, the ladder track’s effect on reducing the vibration of an elevated bridge is analyzed. The analysis results show that the ladder track has good vibration reduction characteristics as compared to ordinary non-ballasted track.

关键词： rail transit elevated bridge ladder track dynamic response

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CORRECTION to: Energy-saving operation approaches for urban rail transit systems

Ziyou GAO, Lixing YANG

《工程管理前沿（英文）》页码 698-698 doi: 10.1007/s42524-019-0047-y

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论城市轨道交通的衔接与发展

闫平

《中国工程科学》 2009年第11卷第1期页码 92-96

摘要：

我国城市公共交通领域已经进入了一个快速发展的建设时期，以北京城市轨道交通规划为例，分析当前我国城市轨道交通在规划、建设及运营方面存在的问题，借鉴国际大都市轨道交通在规划、建设、运营方面的轨道交通方式、客流出行换乘方便、整合既有各种资源、交通带动城市发展的经验，提出了应建立综合协调机制、完善轨道交通规划、打造综合交通枢纽的优化原则，以及利用国有铁路资源实现轨道交通换乘与衔接具体建议。

关键词：城市轨道交通衔接与发展调整建议

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Improvement in growth yield of single-walled carbon nanotubes with narrow chirality distribution by pulse

Bin Xu, Toshiro Kaneko, Toshiaki Kato

《化学科学与工程前沿（英文）》 2019年第13卷第3期页码 485-492 doi: 10.1007/s11705-019-1831-2

摘要： A pulse plasma chemical vapor deposition (CVD) technique was developed for improving the growth yield of single-walled carbon nanotubes (SWNTs) with a narrow chirality distribution. The growth yield of the SWNTs could be improved by repetitive short duration pulse plasma CVD, while maintaining the initial narrow chirality distribution. Detailed growth dynamics is discussed based on a systematic investigation by changing the pulse parameters. The growth of SWNTs with a narrow chirality distribution could be controlled by the difference in the nucleation time required using catalysts comprising relatively small or large particles as the key factor. The nucleation can be controlled by adjusting the pulse on/off time ratio and the total processing time.

关键词： single-walled carbon nanotubes chirality-controlled synthesis pulse plasma chemical vapor deposition

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Characteristics and energy distribution of modulated multi-pulse injection modes based diesel HCCI combustion

LIU Bin, SU Wanhua, WANG Hui, HUANG Haozhong

《能源前沿（英文）》 2007年第1卷第4期页码 420-427 doi: 10.1007/s11708-007-0061-7

摘要： Cycle fuel energy distribution and combustion characteristics of early in-cylinder diesel homogenous charge compression ignition (HCCI) combustion organized by modulated multi-pulse injection modes are studied by the engine test.

关键词： combustion compression homogenous in-cylinder modulated multi-pulse

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High frequency group pulse electrochemical machining

WU Gaoyang, ZHANG Zhijing, ZHANG Weimin, TANG Xinglun

《机械工程前沿（英文）》 2007年第2卷第3期页码 293-296 doi: 10.1007/s11465-007-0051-5

摘要： In the process of machining ultrathin metal structure parts, the signal composition of high frequency group pulse, the influence of frequency to reverse current, and the design of the cathode in high frequency group pulse electrochemical machining (HGPECM) are discussed. The experiments on process were carried out. Results indicate that HGPECM can greatly improve the characteristics of the inter-electrode gap flow field, reduce electrode passivation, and obtain high machining quality. The machining quality is obviously improved by increasing the main pulse frequency. The dimensional accuracy reaches 30 40 ?m and the roughness attained is at 0.30 0.35 ?m. High frequency group pulse electrochemical machining can be successfully used in machining micro-parts.

关键词： HGPECM process machining quality passivation inter-electrode