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Air-bearing position optimization based on dynamic characteristics of ultra-precision linear stages

CHEN Xuedong, LI Zhixin

《机械工程前沿（英文）》 2008年第3卷第4期页码 400-407 doi: 10.1007/s11465-008-0060-z

摘要： Air-bearings are installed between the stator and the mover of ultra-precision linear stages to suppress vibration and mechanical contact. Spring-damping elements are used to emulate the complex interaction of the finite element model (FEM) developed in this paper and the system dynamic behaviors are analyzed. Through the experimental modal test, the validity and reliability of the model are proven. However, the dynamic characteristics including mode frequency, mode shape, and response amplitude are obviously changed with the position of air-bearings. The combined optimization method is used to optimize the air-bearings position. The best and worst positions are obtained using the dynamic characteristic analysis. The method can be generalized to the connection position of different components in manufacture elements and to implement the system dynamic characteristics optimization when the connection position can be changed.

关键词： manufacture different interaction air-bearings response amplitude

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Rolling-element bearings in China: From ancient times to the 20th century

Lie SUN,Ang LI

《机械工程前沿（英文）》 2016年第11卷第1期页码 33-43 doi: 10.1007/s11465-016-0373-2

摘要：

The development of rolling-element bearings in China has spanned a long period. Based on several typical and important cases, the present article reconstructs the history of rolling-element bearings in China by dividing it into four stages according to the various characteristics of the bearings. The first stage represents the origin of rolling bearings in China, which remains controversial because of several suspected races and cages that were likely the components of bearings more than a millennium ago. At the second stage, a type of simple roller bearing was used for astronomical instruments not later than the 13th century based on clear philological and physical evidence. A similar bearing was also applied to an abridged armillary in the 17th century. Another type of spherical thrust bearings with rolling elements, which is a key component of a traditional Chinese windmill, could support a rotating shaft that moves rotationally and at an angle. At the third stage, the Chinese began studying and using the so-called European-style bearing since the 17th century. Moreover, over the last 100 years, the modern rolling bearing industry was gradually established in China, particularly because of the technology transfer from the Soviet Union in the 1950s. At the fourth stage, the Chinese government initiated the relatively rapid development of bearing technology. The government launched the “bearing movement” from the 1950s to the 1960s to establish the modern bearing industry and to promote rolling bearings as replacement for traditional sliding bearings. Furthermore, a number of large professional factories and institutions in China have continually introduced advanced technology and equipment. At present, these companies and institutions play a significant role in the international bearing industry.

关键词： bearing movement rolling-element bearing China early rolling bearings technology transfer

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多孔质气体静压轴承在三轴转台设计中的应用

杜金名

《中国工程科学》 2005年第7卷第1期页码 65-68

摘要：

气体静压轴承广泛应用于航空、航天、精密电子工业中。三轴转台是高精度的测试设备，用来对惯性系统和惯性元件进行检定、标定以及建立相应的误差模型，它的测试精度直接影响航空、航天等飞行器的控制和导航。转台的检测精度与回转轴的回转精度有密切关系。多孔质气体静压轴承同其他节流形式的轴承相比具有很高的承载能力、静态刚度以及很好的阻尼效应。文章对多孔质气体静压轴承进行了理论分析，并同气体静压小孔节流轴承的静态性能进行了比较，结果表明，此类轴承的承载能力明显优于小孔节流轴承。

关键词：气体静压轴承多孔质小孔节流三轴转台

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Review of the damage mechanism in wind turbine gearbox bearings under rolling contact fatigue

Yun-Shuai SU, Shu-Rong YU, Shu-Xin LI, Yan-Ni HE

《机械工程前沿（英文）》 2019年第14卷第4期页码 434-441 doi: 10.1007/s11465-018-0474-1

摘要： Wind turbine gearbox bearings fail with the service life is much shorter than the designed life. Gearbox bearings are subjected to rolling contact fatigue (RCF) and they are observed to fail due to axial cracking, surface flaking, and the formation of white etching areas (WEAs). The current study reviewed these three typical failure modes. The underlying dominant mechanisms were discussed with emphasis on the formation mechanism of WEAs. Although numerous studies have been carried out, the formation of WEAs remains unclear. The prevailing mechanism of the rubbing of crack faces that generates WEAs was questioned by the authors. WEAs were compared with adiabatic shear bands (ASBs) generated in the high strain rate deformation in terms of microstructural compositions, grain refinement, and formation mechanism. Results indicate that a number of similarities exist between them. However, substantial evidence is required to verify whether or not WEAs and ASBs are the same matters.

关键词： rolling contact fatigue (RCF) white etching area (WEA) white etching crack (WEC) adiabatic shear band (ASB)

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新型SMA隔震支座动载性能试验研究

邓宗才,孙宏俊,刘春国,牛坤,邓洪亮

《中国工程科学》 2005年第7卷第12期页码 61-68

摘要：

以提高SMA利用率为目的，设计了几种不同形式的SMA橡胶支座并进行了耗能试验。研究了水平位移幅值、水平加载频率以及竖向荷载等因素对SMA橡胶支座水平刚度、耗能量以及阻尼等基本力学性能的影响，结果表明，新型的SMA橡胶支座均可有效提高橡胶支座的耗能性能和回复能力，并为SMA橡胶支座优化设计提供了依据。

关键词：形状记忆合金隔震支座初始刚度滞回耗能等效阻尼比

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Intercontinental transport of air pollution

Lin ZHANG,

《环境科学与工程前沿（英文）》 2010年第4卷第1期页码 20-29 doi: 10.1007/s11783-010-0014-7

摘要： There is an increasing interest on the intercontinental transport of air pollution among the three main emission regions at northern mid-latitudes: North America, Europe, and East Asia. Air pollutants with sufficient long lifetime can be transported from one continent to another. Observations from ground sites, aircraft and satellites have demonstrated this intercontinental-scale transport of air pollutants in the free troposphere. Numerical models have been applied to understand the pathways of the transport and the impact of intercontinental pollution transport. This paper reviews current observational evidence and modeling studies of intercontinental transport of ozone and its precursors, and the resulting impacts on air quality.

关键词： intercontinental transport ozone air pollution

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Health impacts of air pollution in China

《环境科学与工程前沿（英文）》 2021年第15卷第4期 doi: 10.1007/s11783-020-1367-1

摘要：

•Impacts of air pollution on various body systems health in China were highlighted.

关键词： Health impacts Air pollution China Advances

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Experimental investigation on desiccant air-conditioning system in India

Vijay MITTAL, B. Kant KHAN,

《能源前沿（英文）》 2010年第4卷第2期页码 161-165 doi: 10.1007/s11708-009-0070-5

摘要： An experimental investigation in India was presented to evaluate the performance and energy saving capacity of a desiccant air-conditioning system composed of a silica gel bed, a split type air-conditioner (1.0 ton refrigeration) installed in a room with a volume of 86.4 m, air ducts and a blower. The experiment was made in such a way that the percentages of return air, outdoor air and indoor air mixed with the air leaving the desiccant and desiccant bed thickness could be adjusted. Tests were conducted on several days with relatively similar ambient conditions. Under the test conditions in this experiment, a 7cm bed thickness is recommended with a maximum adsorption rate of 403g/h. The optimum percentages of air ratios were as follows: 10% of outdoor air, 10% of return air (mixed together at the desiccant bed inlet) and 80% of indoor air mixed with the dry air leaving the desiccant. The corresponding electricity saving was about 19%. As expected, simple economic analysis indicates that the desiccant air-conditioning is not viable for smaller cooling capacities.

关键词： air ratios ambient conditions desiccant air-conditioning silica gel

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Phenolic compounds removal by wet air oxidation based processes

Linbi Zhou, Hongbin Cao, Claude Descorme, Yongbing Xie

《环境科学与工程前沿（英文）》 2018年第12卷第1期 doi: 10.1007/s11783-017-0970-2

摘要： Wet air oxidation (WAO) and catalytic wet air oxidation (CWAO) are efficient processes to degrade organic pollutants in water. In this paper, we especially reviewed the WAO and CWAO processes for phenolic compounds degradation. It provides a comprehensive introduction to the CWAO processes that could be beneficial to the scientists entering this field of research. The influence of different reaction parameters, such as temperature, oxygen pressure, pH, stirring speed are analyzed in detail; Homogenous catalysts and heterogeneous catalysts including carbon materials, transitional metal oxides and noble metals are extensively discussed, among which Cu based catalysts and Ru catalysts were shown to be the most active. Three different kinds of the reactor implemented for the CWAO (autoclave, packed bed and membrane reactors) are illustrated and compared. To enhance the degradation efficiency and reduce the cost of the CWAO process, biological degradation can be combined to develop an integrated technology.

关键词： Wet air oxidation Catalytic wet air oxidation Phenolic compounds Heterogeneous catalysts Mechanism

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API-based assessment on urban air environment bearing capability in China

Jinnan WANG,Jing ZHANG,Hongqiang JIANG,Yaling LU

《环境科学与工程前沿（英文）》 2015年第9卷第6期页码 1049-1055 doi: 10.1007/s11783-014-0662-0

摘要： Given the complexity and time-consuming of the conventional environmental capacity based assessment on air environment carrying capacity; a new method for assessing urban air environment carrying capacity based on air pollution index (API) is presented. By using this new method, the air environmental bearing capability of 333 cities at the prefecture level and above is assessed. The results show that of the 333 cities 9.6% is of high bearing capability, 34.5% relatively high bearing capability, 52.6% medium bearing capability, 2.7% low capability, and 0.6% is of weak bearing capability; in terms of regional distribution, the western region is of relatively high air environment bearing capability, followed by north-eastern and eastern regions, and the ambient air quality in the middle region is quite poor; among the 12 urban agglomerations in key regions, Pearl River delta, west side of Taiwan Strait and Chengdu-Chongqing agglomerations are of relatively high carrying capacity while other agglomerations are of medium bearing capability. The assessment results imply that the existing air quality standard (GB3095-1996) is quite unsound.

关键词： air pollution index (API) air environment bearing capability key city assessment method

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Development of an integrated policy making tool for assessing air quality and human health benefits ofair pollution control

Xuezhen QIU,Yun ZHU,Carey JANG,Che-Jen LIN,Shuxiao WANG,Joshua FU,Junping XIE,Jiandong WANG,Dian DING,Shicheng LONG

《环境科学与工程前沿（英文）》 2015年第9卷第6期页码 1056-1065 doi: 10.1007/s11783-015-0796-8

摘要： Efficient air quality management is critical to protect public health from the adverse impacts of air pollution. To evaluate the effectiveness of air pollution control strategies, the US Environmental Protection Agency (US EPA) has developed the Software for Model Attainment Test-Community Edition (SMAT-CE) to assess the air quality attainment of emission reductions, and the Environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) to evaluate the health and economic benefits of air quality improvement respectively. Since scientific decision-making requires timely and coherent information, developing the linkage between SMAT-CE and BenMAP-CE into an integrated assessment platform is desirable. To address this need, a new module linking SMAT-CE to BenMAP-CE has been developed and tested. The new module streamlines the assessment of air quality and human health benefits for a proposed air pollution control strategy. It also implements an optimized data gridding algorithm which significantly enhances the computational efficiency without compromising accuracy. The performance of the integrated software package is demonstrated through a case study that evaluates the air quality and associated economic benefits of a national-level control strategy of PM . The results of the case study show that the proposed emission reduction reduces the number of nonattainment sites from 379 to 25 based on the US National Ambient Air Quality Standards, leading to more than US$334 billion of economic benefits annually from improved public health. The integration of the science-based software tools in this study enhances the efficiency of developing effective and optimized emission control strategies for policy makers.

关键词： air quality assessment human health benefit economic benefit air quality attainment assessment air pollution control strategy decision support system

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Clean air captures attention whereas pollution distracts: evidence from brain activities

《环境科学与工程前沿（英文）》 2023年第18卷第4期 doi: 10.1007/s11783-024-1801-x

摘要：

● We find air pollution distracts attention and reveal the neurocognitive mechanisms.

关键词： Air pollution Attention Disengagement Performance Event-related potential

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Investigation on regeneration and energy storage characteristics of a solar liquid desiccant air-conditioning

SHI Mingheng, DU Bin, ZHAO Yun

《能源前沿（英文）》 2007年第1卷第1期页码 85-90 doi: 10.1007/s11708-007-0008-8

摘要： Solar liquid desiccant air-conditioner is a new air-conditioning system in which liquid desiccant can be regenerated by solar energy and energy can be stored in the form of chemical energy in the liquid desiccant. In this paper regeneration and energy storage characteristics were studied theoretically and experimentally. Two criterion equations for heat and mass transfer in the regeneration process were obtained. The main factors that influence the regeneration process were analyzed. A principal solar liquid desiccant air-conditioning system under energy storage operating mode is proposed.

关键词： desiccant air-conditioning regeneration process air-conditioning system energy regeneration

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New developments in mobile air conditioning systems in China

Jiangping CHEN, Yu ZHAO, Zhaogang QI

《能源前沿（英文）》 2011年第5卷第1期页码 53-58 doi: 10.1007/s11708-010-0137-3

摘要： Global warming poses serious global concerns, and the mobile air conditioning (MAC) industry must be promoted to reduce greenhouse gas emissions. In this paper, the development of the MAC system and components for new energy vehicles, low global warming potential (GWP) refrigerants, methods to control refrigerant leakage, and new energy-saving technologies in China are introduced.

关键词： global warming potential mobile air conditioning (MAC) energy saving new developments

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tree-inspired network: a decision-tree-structured neural network for hierarchical fault diagnosis of bearings

《机械工程前沿（英文）》 2021年第16卷第4期页码 814-828 doi: 10.1007/s11465-021-0650-6

摘要： The fault diagnosis of bearings is crucial in ensuring the reliability of rotating machinery. Deep neural networks have provided unprecedented opportunities to condition monitoring from a new perspective due to the powerful ability in learning fault-related knowledge. However, the inexplicability and low generalization ability of fault diagnosis models still bar them from the application. To address this issue, this paper explores a decision-tree-structured neural network, that is, the deep convolutional tree-inspired network (DCTN), for the hierarchical fault diagnosis of bearings. The proposed model effectively integrates the advantages of convolutional neural network (CNN) and decision tree methods by rebuilding the output decision layer of CNN according to the hierarchical structural characteristics of the decision tree, which is by no means a simple combination of the two models. The proposed DCTN model has unique advantages in 1) the hierarchical structure that can support more accuracy and comprehensive fault diagnosis, 2) the better interpretability of the model output with hierarchical decision making, and 3) more powerful generalization capabilities for the samples across fault severities. The multiclass fault diagnosis case and cross-severity fault diagnosis case are executed on a multicondition aeronautical bearing test rig. Experimental results can fully demonstrate the feasibility and superiority of the proposed method.

关键词： bearing cross-severity fault diagnosis hierarchical fault diagnosis convolutional neural network decision tree