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The formation mechanism and the influence factor of residual stress in machining

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 265-269 doi: 10.1007/s11465-014-0311-0

摘要:

Residual stresses generated in cutting process have important influences on workpiece performance. The paper presents a method of theoretical analysis in order to explicate the formation mechanism of residual stresses in cutting. An important conclusion is drawn that the accumulated plastic strain is the main factor which determines the nature and the magnitude of surface residual stresses in the workpiece. On the basis of the analytical model for residual stress, a series of simulations for residual stress prediction during cutting AISI 1045 steel are implemented in order to obtain the influences of cutting speed, depth of cut and tool edge radius on surface residual stress in the workpiece. And these influences are explained from the perspective of formation mechanism of residual stress in cutting. The conclusions have good applicability and can be used to guide the parameters selection in actual production.

关键词: residual stress     analytical model     strain     plastic     cutting parameter    

Numerical investigation of the influence of kinetics and shape factor on barium sulfate precipitation

Zheng WANG, Zai-Sha MAO, Chao YANG, Qinghua ZHANG, Jingcai CHENG

《化学科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 272-281 doi: 10.1007/s11705-009-0023-x

摘要: The effect of kinetics and shape factor on barium sulfate precipitation in a continuous stirred tank has been investigated numerically through solving the standard momentum and mass transport equations in combination with the moment equations for crystal population balance. The numerical method was validated with the literature data. The simulated results include the distribution of the local supersaturation ratio in the reactor, the mean crystal size, and the coefficient of variation. The simulation results show that the value of shape factor used in the model affected greatly the mean crystal size and the moments of the crystal size distribution. The influence of the kinetic expressions on the simulation is also analyzed. It is important to investigate the relationship of the shape factor with the precipitator type and other operation conditions to obtain reliable simulation results and suitable kinetic equations of crystal nucleation and growth rates.

关键词: stirred tank     numerical simulation     precipitation     shape factor     crystal kinetics    

Factors influencing near infrared spectroscopy analysis of agro-products: a review

Xiao XU, Lijuan XIE, Yibin YING

《农业科学与工程前沿(英文)》 2019年 第6卷 第2期   页码 105-115 doi: 10.15302/J-FASE-2019255

摘要:

The near infrared (NIR) spectroscopy technique has wide applications in agriculture with the advantages of being nondestructive, sensitive, safe and rapid. However, there are still more than 40 error sources influencing the robustness and accuracy of its calibration and operation. Environmental, sample and instrument factors that influence the analysis are discussed in this review, including temperature, humidity and other factors that introduce uncertainty. Error sources from livestock products, fruit and vegetables, which are the most common objects in the field of NIR analysis, are also emphasized in the second part. In addition, studies utilizing different instruments, spectral pretreatments, variable selection methods, wavelength ranges, detection modes and calibration methods are tabulated to illustrate the complications they introduce and how they influence NIR analysis. It is suggested that large scale of data with abundant varieties can be used to build a more robust calibration model, in order to improve the robustness and accuracy of the NIR analytical model, and overcome problems caused by confining analysis to too many uniform samples.

关键词: agro-product     error source     influence factor     near infrared spectroscopy    

Mechanism of self-excited torsional vibration of locomotive driving system

Jianxin LIU, Huaiyun ZHAO, Wanming ZHAI

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 465-469 doi: 10.1007/s11465-010-0115-9

摘要: A single wheelset drive model and 2-DOFs torsional vibration model were established to investigate the self-excited torsional vibration of a locomotive driving system. The simulation results indicate that the self-excited torsional vibration occurs when the steady slip velocity is located at the descending slope of the adhesion coefficient curve. The principle of energy conservation was used to analyze the mechanism of the self-excited vibration. The factors affecting on the amplitude of the self-excited vibration are studied.

关键词: locomotive     driving system     self-excited torsional vibration     mechanism     influence factor    

Carbon emission analysis of a residential building in China through life cycle assessment

Yin ZHANG,Xuejing ZHENG,Huan ZHANG,Gaofeng CHEN,Xia WANG

《环境科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 150-158 doi: 10.1007/s11783-014-0684-7

摘要: In this paper, a quantitative life cycle model for carbon emission accounting was developed based on the life cycle assessment (LCA) theory. A residential building in Sino-Singapore Tianjin Eco-city (Tianjin, China) was selected as a sample, which had been constructed according to the concept of green environmental protection and sustainable development. In the scenario of this research, material production, construction, use and maintenance, and demolition phases were assessed by building carbon emission models. Results show that use and maintenance phase and material production phase are the most significant contributors to the life cycle carbon emissions of a building. We also analyzed some factor influences in LCA, including the thickness of the insulating layer and the length of building service life. The analysis suggest that thicker insulating layer does not necessarily produce less carbon emissions in the light of LCA, and if service life of a building increases, its carbon emissions during the whole life cycle will rise as well but its unit carbon emission will decrease inversely. Some advices on controlling carbon emissions from buildings are also provided.

关键词: life cycle assessment     carbon emission     factor influence analysis    

Identifying factors that influence soil heavy metals by using categorical regression analysis: A case

Jun Yang, Jingyun Wang, Pengwei Qiao, Yuanming Zheng, Junxing Yang, Tongbin Chen, Mei Lei, Xiaoming Wan, Xiaoyong Zhou

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-019-1216-2

摘要: A method was proposed to identify the main influence factors of soil heavy metals. The influence degree of different environmental factors was ranked. Parent material, soil type, land use and industrial activity were main factors. Interactions between some factors obviously affected soil heavy metal distribution. Identifying the factors that influence the heavy metal contents of soil could reveal the sources of soil heavy metal pollution. In this study, a categorical regression was used to identify the factors that influence soil heavy metals. First, environmental factors were associated with soil heavy metal data, and then, the degree of influence of different factors on the soil heavy metal contents in Beijing was analyzed using a categorical regression. The results showed that the soil parent material, soil type, land use type, and industrial activity were the main influencing factors, which suggested that these four factors were important sources of soil heavy metals in Beijing. In addition, population density had a certain influence on the soil Pb and Zn contents. The distribution of soil As, Cd, Pb, and Zn was markedly influenced by interactions, such as traffic activity and land use type, industrial activity and population density. The spatial distribution of soil heavy metal hotspots corresponded well with the influencing factors, such as industrial activity, population density, and soil parent material. In this study, the main factors affecting soil heavy metals were identified, and the degree of their influence was ranked. A categorical regression represents a suitable method for identifying the factors that influence soil heavy metal contents and could be used to study the genetic process of regional soil heavy metal pollution.

关键词: Soil     Heavy metal     Influencing factor     Categorical regression     Identification method    

Landscape of emerging and re-emerging infectious diseases in China: impact of ecology, climate, and behavior

null

《医学前沿(英文)》 2018年 第12卷 第1期   页码 3-22 doi: 10.1007/s11684-017-0605-9

摘要:

For the past several decades, the infectious disease profile in China has been shifting with rapid developments in social and economic aspects, environment, quality of food, water, housing, and public health infrastructure. Notably, 5 notifiable infectious diseases have been almost eradicated, and the incidence of 18 additional notifiable infectious diseases has been significantly reduced. Unexpectedly, the incidence of over 10 notifiable infectious diseases, including HIV, brucellosis, syphilis, and dengue fever, has been increasing. Nevertheless, frequent infectious disease outbreaks/events have been reported almost every year, and imported infectious diseases have increased since 2015. New pathogens and over 100 new genotypes or serotypes of known pathogens have been identified. Some infectious diseases seem to be exacerbated by various factors, including rapid urbanization, large numbers of migrant workers, changes in climate, ecology, and policies, such as returning farmland to forests. This review summarizes the current experiences and lessons from China in managing emerging and re-emerging infectious diseases, especially the effects of ecology, climate, and behavior, which should have merits in helping other countries to control and prevent infectious diseases.

关键词: infectious disease profile     emerging infectious diseases     influence factor    

耐污染反渗透/纳滤复合膜研究进展

秦嘉旭,张林,侯立安

《中国工程科学》 2014年 第16卷 第7期   页码 30-35

摘要:

膜污染防控是反渗透(RO)、纳滤膜研究的重要方向,是影响其应用的关键环节。本文总结了常见的反渗透膜污染类型,并对影响反渗透膜污染的关键因素进行分析;并重点综述了目前提高反渗透膜耐污性的方法,包括设计新型关键单体、表面物理改性、表面化学改性及共混改性等方法;最后对耐污染反渗透膜的研究进行了展望。

关键词: 反渗透膜     耐污染     影响因素     膜材料     改性方法    

Identifying spreading influence nodes for social networks

《工程管理前沿(英文)》   页码 520-549 doi: 10.1007/s42524-022-0190-8

摘要: The identification of spreading influence nodes in social networks, which studies how to detect important individuals in human society, has attracted increasing attention from physical and computer science, social science and economics communities. The identification algorithms of spreading influence nodes can be used to evaluate the spreading influence, describe the node’s position, and identify interaction centralities. This review summarizes the recent progress about the identification algorithms of spreading influence nodes from the viewpoint of social networks, emphasizing the contributions from physical perspectives and approaches, including the microstructure-based algorithms, community structure-based algorithms, macrostructure-based algorithms, and machine learning-based algorithms. We introduce diffusion models and performance evaluation metrics, and outline future challenges of the identification of spreading influence nodes.

关键词: complex network     network science     spreading influence     machine learning    

Role of the forkhead transcription factor FOXO-FOXM1 axis in cancer and drug resistance

null

《医学前沿(英文)》 2012年 第6卷 第4期   页码 376-380 doi: 10.1007/s11684-012-0228-0

摘要:

The forkhead transcription factors FOXO and FOXM1 have pivotal roles in tumorigenesis and in mediating chemotherapy sensitivity and resistance. Recent research shows that the forkhead transcription factor FOXM1 is a direct transcriptional target repressed by the forkhead protein FOXO3a, a vital downstream effector of the PI3K-AKT-FOXO signaling pathway. Intriguingly, FOXM1 and FOXO3a also compete for binding to the same gene targets, which have a role in chemotherapeutic drug action and sensitivity. An understanding of the role and regulation of the FOXO-FOXM1 axis will impact directly on our knowledge of chemotherapeutic drug action and resistance in patients, and provide new insights into the design of novel therapeutic strategy and reliable biomarkers for prediction of drug sensitivity.

关键词: FOXO3a     FOXM1     transcription factor     cancer     drug resistance     tumorigenesis    

LSSVM-based approach for refining soil failure criteria and calculating safety factor of slopes

Shiguo XIAO; Shaohong LI

《结构与土木工程前沿(英文)》 2022年 第16卷 第7期   页码 871-881 doi: 10.1007/s11709-022-0863-8

摘要: The failure criteria of practical soil mass are very complex, and have significant influence on the safety factor of slope stability. The Coulomb strength criterion and the power-law failure criterion are classically simplified. Each one has limited applicability owing to the noticeable difference between calculated predictions and actual results in some cases. In the work reported here, an analysis method based on the least square support vector machine (LSSVM), a machine learning model, is purposefully provided to establish a complex nonlinear failure criterion via iteration computation based on strength test data of the soil, which is of more extensive applicability to many problems of slope stability. In particular, three evaluation indexes including coefficient of determination, mean absolute percentage error, and mean square error indicate that fitting precision of the machine learning-based failure criterion is better than those of the linear Coulomb criterion and nonlinear power-law criterion. Based on the proposed LSSVM approach to determine the failure criterion, the limit equilibrium method can be used to calculate the safety factor of three-dimensional slope stability. Analysis of results of the safety factor of two three-dimensional homogeneous slopes shows that the maximum relative errors between the proposed approach and the linear failure criterion-based method and the power-law failure criterion-based method are about 12% and 7%, respectively.

关键词: slope stability     safety factor     failure criterion     least square support vector machine    

lncR-GAS5 upregulates the splicing factor to impair endothelial autophagy, leading to atherogenesis

《医学前沿(英文)》 2023年 第17卷 第2期   页码 317-329 doi: 10.1007/s11684-022-0931-4

摘要: Long noncoding RNAs (lncRNAs) play a critical role in the regulation of atherosclerosis. Here, we investigated the role of the lncRNA growth arrest-specific 5 (lncR-GAS5) in atherogenesis. We found that the enforced expression of lncR-GAS5 contributed to the development of atherosclerosis, which presented as increased plaque size and reduced collagen content. Moreover, impaired autophagy was observed, as shown by a decreased LC3II/LC3I protein ratio and an elevated P62 level in lncR-GAS5-overexpressing human aortic endothelial cells. By contrast, lncR-GAS5 knockdown promoted autophagy. Moreover, serine/arginine-rich splicing factor 10 (SRSF10) knockdown increased the LC3II/LC3I ratio and decreased the P62 level, thus enhancing the formation of autophagic vacuoles, autolysosomes, and autophagosomes. Mechanistically, lncR-GAS5 regulated the downstream splicing factor SRSF10 to impair autophagy in the endothelium, which was reversed by the knockdown of SRSF10. Further results revealed that overexpression of the lncR-GAS5-targeted gene miR-193-5p promoted autophagy and autophagic vacuole accumulation by repressing its direct target gene, SRSF10. Notably, miR-193-5p overexpression decreased plaque size and increased collagen content. Altogether, these findings demonstrate that lncR-GAS5 partially contributes to atherogenesis and plaque instability by impairing endothelial autophagy. In conclusion, lncR-GAS5 overexpression arrested endothelial autophagy through the miR-193-5p/SRSF10 signaling pathway. Thus, miR-193-5p/SRSF10 may serve as a novel treatment target for atherosclerosis.

关键词: lncR-GAS5     miR-193-5p     splicing factor SRSF10     autophagy     atherogenesis    

The calculation of equivalence factor for ecological footprints in China: a methodological note

Moucheng LIU,Wenhua LI,Dan ZAHNG,Ning SU

《环境科学与工程前沿(英文)》 2015年 第9卷 第6期   页码 1015-1024 doi: 10.1007/s11783-014-0670-0

摘要: The Ecological Footprint (EF), a physical indicator to measure the extent of humanity’s use of natural resources, has gained much attention since it was first used by Wackernagel and Rees in 1996. In order to appraise land area types with different levels of productivity, they introduced the concept of an equivalence factor. This relates to the average primary biomass productivities of different types of land (i.e. arable land, pasture, forest, water/fishery, built-up land and fossil energy land) to the regional average primary biomass productivity of all land types in a given year. Hence, the equivalence factor is an important parameter in the EF model and it directly affects the reliability of all results. Thus, this article calculates equivalence factors on the national and provincial levels in China based on Net Primary Production (NPP) from MODIS 1 km data in 2008. Firstly, based on the Light Utility Efficiency and CASA model, the NPP of different biologically productive lands of China and of different provinces was calculated. Secondly, China’s equivalence factor for 6 land area types was calculated based on NPP: arable land and built-up land has an equivalence factor of 1.71, forest and fossil energy land has a factor of 1.41, pasture has a factor of 0.44 and water/fishery 0.35; Finally, the equivalence factor of 6 land area types in different provinces was also calculated. The NPP of each ecosystem type varies along with the equivalence factor in different provinces. However, the ranking of the equivalence factors in different provinces remain the same, with that of arable land being the largest, and the water/fishery being the smallest.

关键词: ecological footprint     equivalence factor     net primary production     biological capacity     land types    

Heterogeneous influence of individuals’ behavior on mask efficacy in gathering environments

《工程管理前沿(英文)》   页码 550-562 doi: 10.1007/s42524-022-0193-5

摘要: Wearing masks is an easy way to operate and popular measure for preventing epidemics. Although masks can slow down the spread of viruses, their efficacy in gathering environments involving heterogeneous person-to-person contacts remains unknown. Therefore, we aim to investigate the epidemic prevention effect of masks in different real-life gathering environments. This study uses four real interpersonal contact datasets to construct four empirical networks to represent four gathering environments. The transmission of COVID-19 is simulated using the Monte Carlo simulation method. The heterogeneity of individuals can cause mask efficacy in a specific gathering environment to be different from the baseline efficacy in general society. Furthermore, the heterogeneity of gathering environments causes the epidemic prevention effect of masks to differ. Wearing masks can greatly reduce the probability of clustered epidemics and the infection scale in primary schools, high schools, and hospitals. However, the use of masks alone in primary schools and hospitals cannot control outbreaks. In high schools with social distancing between classes and in workplaces where the interpersonal contact is relatively sparse, masks can meet the need for prevention. Given the heterogeneity of individual behavior, if individuals who are more active in terms of interpersonal contact are prioritized for mask-wearing, the epidemic prevention effect of masks can be improved. Finally, asymptomatic infection has varying effects on the prevention effect of masks in different environments. The effect can be weakened or eliminated by increasing the usage rate of masks in high schools and workplaces. However, the effect on primary schools and hospitals cannot be weakened. This study contributes to the accurate evaluation of mask efficacy in various gathering environments to provide scientific guidance for epidemic prevention.

关键词: COVID-19     masks     behavioral heterogeneity     asymptomatic infection    

社会影响力分析——模型、方法和评价 Review

李侃, 张林, 黄河燕

《工程(英文)》 2018年 第4卷 第1期   页码 40-46 doi: 10.1016/j.eng.2018.02.004

摘要:

社会影响力分析(SIA)是一个广泛的研究领域,吸引了诸多研究者的兴趣。本文总结了SIA 相关的模型、方法和评价方面代表性的工作,并将SIA 模型归纳为两种类型:微观模型和宏观模型。微观模型考虑人与人之间的相互影响和影响的过程,而宏观模型认为每个人具有相同的传播概率和影响力。本文分析了包括影响最大化、影响最小化、影响流和个人影响力等的社会影响力分析方法;介绍了影响力评价指标,并分析了社会影响力评价模型。本文的目标是对社会影响力提供全面的分析,旨在辅助理解社会行为,为舆论影响提供理论基础,并揭示未来的研究方向和潜在的应用。

关键词: 社会影响力分析     在线社交网络     社会影响力分析模型     影响力评价    

标题 作者 时间 类型 操作

The formation mechanism and the influence factor of residual stress in machining

null

期刊论文

Numerical investigation of the influence of kinetics and shape factor on barium sulfate precipitation

Zheng WANG, Zai-Sha MAO, Chao YANG, Qinghua ZHANG, Jingcai CHENG

期刊论文

Factors influencing near infrared spectroscopy analysis of agro-products: a review

Xiao XU, Lijuan XIE, Yibin YING

期刊论文

Mechanism of self-excited torsional vibration of locomotive driving system

Jianxin LIU, Huaiyun ZHAO, Wanming ZHAI

期刊论文

Carbon emission analysis of a residential building in China through life cycle assessment

Yin ZHANG,Xuejing ZHENG,Huan ZHANG,Gaofeng CHEN,Xia WANG

期刊论文

Identifying factors that influence soil heavy metals by using categorical regression analysis: A case

Jun Yang, Jingyun Wang, Pengwei Qiao, Yuanming Zheng, Junxing Yang, Tongbin Chen, Mei Lei, Xiaoming Wan, Xiaoyong Zhou

期刊论文

Landscape of emerging and re-emerging infectious diseases in China: impact of ecology, climate, and behavior

null

期刊论文

耐污染反渗透/纳滤复合膜研究进展

秦嘉旭,张林,侯立安

期刊论文

Identifying spreading influence nodes for social networks

期刊论文

Role of the forkhead transcription factor FOXO-FOXM1 axis in cancer and drug resistance

null

期刊论文

LSSVM-based approach for refining soil failure criteria and calculating safety factor of slopes

Shiguo XIAO; Shaohong LI

期刊论文

lncR-GAS5 upregulates the splicing factor to impair endothelial autophagy, leading to atherogenesis

期刊论文

The calculation of equivalence factor for ecological footprints in China: a methodological note

Moucheng LIU,Wenhua LI,Dan ZAHNG,Ning SU

期刊论文

Heterogeneous influence of individuals’ behavior on mask efficacy in gathering environments

期刊论文

社会影响力分析——模型、方法和评价

李侃, 张林, 黄河燕

期刊论文