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《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0735-x
关键词: electromechanical-hydraulic hybrid actuator (EMHA) integration transmission mechanisms power assistance energy efficiency working characteristics
Choosing configurations of transmission line tower grounding by back flashover probability value
Dmitry KUKLIN
《能源前沿(英文)》 2016年 第10卷 第2期 页码 213-226 doi: 10.1007/s11708-016-0398-6
关键词: grounding transmission line tower back flashover probability FDTD method
FOOD SYSTEMS TRANSFORMATION: CONCEPTS, MECHANISMS AND PRACTICES
《农业科学与工程前沿(英文)》 2023年 第10卷 第1期 页码 1-3 doi: 10.15302/J-FASE-2023491
Gripping mechanisms in current wood harvesting machines
D. GOUBET, J. C. FAUROUX, G. GOGU
《机械工程前沿(英文)》 2013年 第8卷 第1期 页码 42-61 doi: 10.1007/s11465-013-0358-3
This paper focuses on the structural synthesis of gripping mechanisms used in the mechanization of the harvesting process. The importance of the gripping function in current devices like harvesting heads is underlined. This function is performed with several typical mechanisms which are listed and described in this article. This study distinguishes two kinds of planar gripping mechanisms mainly used in opening and closing the rollers: five concentric and two lateral ones. Both kinds have advantages and drawbacks. So a third kind of hybrid mechanism has been designed in order to orientate the axis of the rollers during gripping motion in order to combine concentric and lateral gripping advantages. Two planar and one spatial existing mechanisms are described. The last part of this paper presents a structural synthesis of such a spatial parallel mechanism by using the structural parameters and the general formulae established by the third author. Nine kinematic diagrams of spatial parallel mechanisms are provided.
关键词: structural synthesis parallel mechanisms gripping mechanisms wood harvesting harvesting head
Recent development on innovation design of reconfigurable mechanisms in China
Wuxiang ZHANG, Shengnan LU, Xilun DING
《机械工程前沿(英文)》 2019年 第14卷 第1期 页码 15-20 doi: 10.1007/s11465-018-0517-7
关键词: innovation design reconfigurable mechanisms metamorphic mechanisms origami-derived mechanisms development trends
null
《医学前沿(英文)》 2018年 第12卷 第1期 页码 76-83 doi: 10.1007/s11684-017-0609-5
Tuberculosis (TB) has remained an ongoing concern in China. The national scale-up of the Directly Observed Treatment, Short Course (DOTS) program has accelerated the fight against TB in China. Nevertheless, many challenges still remain, including the spread of drug-resistant strains, high disease burden in rural areas, and enormous rural-to-urban migrations. Whether incident active TB represents recent transmission or endogenous reactivation has helped to prioritize the strategies for TB control. Evidence from molecular epidemiology studies has delineated the recent transmission of ( ) strains in many settings. However, the transmission patterns of TB in most areas of China are still not clear. Studies carried out to date could not capture the real burden of recent transmission of the disease in China because of the retrospective study design, incomplete sampling, and use of low-resolution genotyping methods. We reviewed the implementations of molecular epidemiology of TB in China, the estimated disease burden due to recent transmission of strains, the primary transmission of drug-resistant TB, and the evaluation of a feasible genotyping method of strains in circulation.
关键词: tuberculosis recent transmission molecular epidemiology China
CROP DIVERSITY AND SUSTAINABLE AGRICULTURE: MECHANISMS, DESIGNS AND APPLICATIONS
《农业科学与工程前沿(英文)》 2021年 第8卷 第3期 页码 359-361 doi: 10.15302/J-FASE -2021417
Intensive monoculture agriculture has contributed greatly to global food supply over many decades, but the excessive use of agricultural chemicals (fertilizers, herbicides and pesticides) and intensive cultivation systems has resulted in negative side effects, such as soil erosion, soil degradation, and non-point source pollution[1]. To many observers, agriculture looms as a major global threat to nature conservation and biodiversity. As noted in the Global Biodiversity Outlook 4[2], the drivers associated with food systems and agriculture account for around 70% and 50% of the projected losses by 2050 of terrestrial and freshwater biodiversity, respectively[3].
In addition, agricultural development and modernization of agriculture has led to a decline in the total number of plant species upon which humans depend for food[4]. Currently, fewer than 200 of some 6000 plant species grown for food contribute substantially to global food output, and only nine species account for 67% of total crop production[3]. The global crop diversity has declined in past decades.
Crop species diversity at a national scale was identified as one of the most important factors that stabilize grain production at a national level[5]. A group of long-term field experiments demonstrated that crop diversity also stabilizes temporal grain productivity at field level[6]. Therefore, maintaining crop diversity at both national and field levels is of considerable importance for food security at national and global scales.
Crop diversity includes temporal (crop rotation) and spatial diversity (e.g., intercropping, agroforestry, cultivar mixtures and cover crops) at field scale. Compared to intensive monocultures, diversified cropping systems provide additional options to support multiple ecosystem functions. For instance, crop diversity may increase above- and belowground biodiversity, improve yield stability, reduce pest and disease damage, reduce uses of chemicals, increase the efficiency of the use land, light water and nutrient resources, and enhance stress resilience in agricultural systems.
To highlight advances in research and use of crop diversity, from developing and developed countries, we have prepared this special issue on “Crop Diversity and Sustainable Agriculture” for Frontiers of Agricultural Sciences and Engineering, mainly focusing on intercropping.
Intercropping, growing at least two crops at the same time as a mixture, for example, in alternate rows or strips, is one effective pathway for increasing crop diversity at the field scale. Over recent decades, there have been substantial advances in terms of understanding of processes between intercropped species and applications in practice. There are 10 articles in this special issue including letters, opinions, review and research articles with contributions from Belgium, China, Denmark, France, Germany, Greece, Italy, the Netherlands, Spain, Switzerlands, UK, and Mexico etc.
The contributors are internationally-active scientists and agronomists contributing to intercropping research and extension. For example, Antoine Messean is coordinator of the EU H2020 Research project DiverIMPACTS “Diversification through rotation, intercropping, multiple cropping, promoted with actors and value chains towards sustainability”. Eric Justes is coordinator of the EU H2020 Research project ReMIX “Redesigning European cropping systems based on species mixtures”. Maria Finckh has worked on crop cultivar mixture and organic agriculture over many years. Henrik Hauggaard-Nielsen has outstanding expertise in intercropping research and applications, moving from detailed studies on species interactions in intercropping to working with farmers and other stakeholders to make intercropping work in practical farming. In addition to these established scientists, young scientists who have taken an interest in intercropping also contribute to the special issue, including Wen-Feng Cong, Yixiang Liu, Qi Wang, Hao Yang and others.
The first contribution to this special issue addresses how to design cropping systems to reach crop diversification, with Wen-Feng Cong and coworkers ( https://doi.org/10.15302/J-FASE-2021392) considering that it is necessary to optimize existing and/or design novel cropping systems based on farming practices and ecological principles, and to strengthen targeted ecosystem services to achieve identified objectives. In addition, the design should consider regional characteristics with the concurrent objectives of safe, nutritious food production and environmental protection.
The benefits of crop diversification have been demonstrated in many studies. Wen-Feng Cong and coworkers describe the benefits of crop diversification at three scales: field, farm, and landscape. Hao Yang and coauthors reviewed the multiple functions of intercropping. Intercropping enhances crop productivity and its stability, it promotes efficient use of resources and saves mineral fertilizer, controls pests and diseases of crops and reduces the use of pesticides. It mitigates climate change by sequestering carbon in soil, reduces non-point source pollution, and increases above- and belowground biodiversity of other taxa at field scale ( https://doi.org/10.15302/J-FASE-2021398).
Eric Justes and coworkers proposed the “4C” framework to help understand the role of species interactions in intercropping ( https://doi.org/10.15302/J-FASE-2021414). The four components are competition, complementary, cooperation (facilitation) and compensation, which work often simultaneously in intercropping. Hao Yang and coworkers used the concept of diversity effect from ecology to understand the contribution of complementarity and selection effects to enhanced productivity in intercropping. The complementarity effect consists of interspecific facilitation and niche differentiation between crop species, whereas the selection effect is mainly derived from competitive processes between species such that one species dominates the other ( https://doi.org/10.15302/J-FASE-2021398). Also, Luis Garcia-Barrios and Yanus A. Dechnik-Vazquez dissected the ecological concept of the complementarity and selection effects to develop a relative multicrop resistance index to analyze the relation between higher multicrop yield and land use efficiency and the different ecological causes of overyielding under two contrasting water stress regimes ( https://doi.org/10.15302/J-FASE-2021412).
Odette Denise Weedon and Maria Renate Finckh found that composite cross populations, with different disease susceptibilities of three winter wheat cultivars, were moderately resistant to brown rust and even to the newly emerged stripe rust races prevalent in Europe since 2011, but performance varied between standard and organic management contexts ( https://doi.org/10.15302/J-FASE-2021394).
Comparing the performance of intercrops and sole crops is critical to make a sound evaluation of the benefits of intercropping and assess interactions between species choice, intercrop design, intercrop management and factors related to the production situation and pedoclimatic context. Wopke van der Werf and coworkers review some of the metrics that could be used in the quantitative synthesis of literature data on intercropping ( https://doi.org/10.15302/J-FASE-2021413).
Interspecific interactions provide some of the advantages of intercropping, and can be divided into above- and belowground interactions. Aboveground interactions can include light and space competition, which is influenced by crop species traits. Root exudates are also important in interspecific interactions between intercropped or rotated species. Qi Wang and coworkers estimated the light interception of growth stage of maize-peanut intercropping and corresponding monocultures, and found that intercropping has higher light interception than monoculture, and increasing plant density did not further increase light interception of intercropping ( https://doi.org/10.15302/J-FASE-2021403). Yuxin Yang and coworkers reported that the root exudates of fennel (Foeniculum vulgare) can reduce infection of tobacco by Phytophthora nicotianae via inhibiting the motility and germination of the spores of the pathogen ( https://doi.org/10.15302/J-FASE-2021399).
Focusing on the application of intercropping, Wen-Feng Cong and coworkers formulated species recommendations for different regions of China for different crop diversity patterns and crop species combinations. These authors also suggested three steps for implementing crop diversification on the North China Plain. Although there are multiple benefits of crop diversification, its extension and application are hindered by various technical, organizational, and institutional barriers along value chains, especially in Europe. Based on the findings of the European Crop Diversification Cluster projects, Antoine Messéan and coworkers suggested that there needs to be more coordination and cooperation between agrifood system stakeholders, and establish multiactor networks, toward an agroecological transition of European agriculture ( https://doi.org/10.15302/J-FASE-2021406). In addition, Henrik Hauggaard-Nielsen and coworkers report the outcomes of a workshop for participatory research to overcome the barriers to enhanced coordination and networking between stakeholders ( https://doi.org/10.15302/J-FASE-2021416).
Intercropping, though highly effective in labor-intensive agriculture, may be difficult to implement in machine-intensive, large-scale modern agriculture because appropriate large equipment is not commercially available for planting and harvesting various crop mixtures grown with strip intercropping[6]. Thus, the appropriate machinery will need to be developed for further practical application in large-scale agriculture.
As the guest editors, we thank all the authors and reviewers for their great contributions to this special issue on “Crop Diversity and Sustainable Agriculture”. We also thank the FASE editorial team for their kind supports.
Antibiotic resistome mostly relates to bacterial taxonomy along a suburban transmission chain
《环境科学与工程前沿(英文)》 2022年 第16卷 第3期 doi: 10.1007/s11783-021-1466-7
• The α-diversities of resistome were lower in manure and compost than in soils.
关键词: Antibiotic resistance genes Resistome Bacterial taxonomy Transmission chain
Planet position errors in planetary transmission: Effect on load sharing and transmission error
Miguel IGLESIAS, Alfonso FERNáNDEZ, Ana DE-JUAN, Ramón SANCIBRIáN, Pablo GARCíA
《机械工程前沿(英文)》 2013年 第8卷 第1期 页码 80-87 doi: 10.1007/s11465-013-0362-7
In this paper an advanced model of spur gear transmissions developed by the authors is used to study the influence of carrier planet pin hole position errors on the behaviour of the transmission. The model, initially conceived for external gear modeling, has been extended with internal meshing features, and thus increasing its capabilities to include planetary transmission modeling. The new features are presented, along with the summary of the model general approach. The parameters and characteristics of the planetary transmission used in the paper are introduced. The influence of carrier planet pin hole position errors on the planet load sharing is studied, and several static cases are given as examples in order to show the ability of the model. Tangential and radial planet pin hole position errors are considered independently, and the effect of the load level is also taken into account. It is also given attention to the effect on the transmission error of the transmission. Two different configurations for the planetary transmission are used, attending to the fixed or floating condition of the sun, and the differences in terms of load sharing ratio are shown.
关键词: gear planetary epicyclic transmission load sharing transmission error
Eliminating mother-to-child transmission of HBV: progress and challenges in China
Wenzhan Jing, Jue Liu, Min Liu
《医学前沿(英文)》 2020年 第14卷 第1期 页码 21-29 doi: 10.1007/s11684-020-0744-2
关键词: hepatitis B virus mother-to-child transmission progress challenge
Rongrit CHATTHAWORN,Surachai CHAITUSANEY
《信息与电子工程前沿(英文)》 2015年 第16卷 第10期 页码 871-882 doi: 10.1631/FITEE.1500049
关键词: Adaptive tabu search Renewable energy generation Robust optimization Transmission expansion planning
《环境科学与工程前沿(英文)》 2021年 第15卷 第3期 doi: 10.1007/s11783-021-1386-6
• Aerosol transmission is an indispensable route of COVID-19 spread.
关键词: SARS-CoV-2 COVID-19 Environmental factor Aerosol transmission Epidemiologic characteristic
Mass transport mechanisms within pervaporation membranes
Yimeng Song, Fusheng Pan, Ying Li, Kaidong Quan, Zhongyi Jiang
《化学科学与工程前沿(英文)》 2019年 第13卷 第3期 页码 458-474 doi: 10.1007/s11705-018-1780-1
关键词: pervaporation membrane mass transport mechanisms physical mechanism chemical mechanism
Baicheng HUANG, Kegong TIAN
《农业科学与工程前沿(英文)》 2020年 第7卷 第2期 页码 218-226 doi: 10.15302/J-FASE-2020324
Emergent coronaviruses (CoVs) such as SARS-CoV and MERS-CoV have posed great threats to public health worldwide over the past two decades. Currently, the emergence of SARS-CoV-2 as a pandemic causes greater public health concern. CoV diversity is due to the large size and replication mechanisms of the genomes together with having bats as their optimum natural hosts. The ecological behavior and unique immune characteristics of bats are optimal for the homologous recombination of CoVs. The relationship of spatial structural characteristics of the spike protein, a protein that is critical for recognition by host receptors, in different CoVs may provide evidence in explaining the coevolution of CoVs and their hosts. This information may help to enhance our understanding of CoV evolution and thus provide part of the basis of preparations for any future outbreaks.
关键词: bat coronavirus evolution host receptor spike protein transmission
Reliability analysis of urban gas transmission and distribution system based on FMEA and correlation
Su LI,Weiguo ZHOU
《能源前沿(英文)》 2014年 第8卷 第4期 页码 443-448 doi: 10.1007/s11708-014-0336-4
关键词: gas transmission and distribution system risk evaluation reliability analysis failure mode and effects analysis (FMEA) correlation operator
标题 作者 时间 类型 操作
Design and characteristic research of a novel electromechanical-hydraulic hybrid actuator with two transmissionmechanisms
期刊论文
Choosing configurations of transmission line tower grounding by back flashover probability value
Dmitry KUKLIN
期刊论文
Recent development on innovation design of reconfigurable mechanisms in China
Wuxiang ZHANG, Shengnan LU, Xilun DING
期刊论文
Recent transmission of Mycobacterium tuberculosis in China: the implication of molecular epidemiology
null
期刊论文
Planet position errors in planetary transmission: Effect on load sharing and transmission error
Miguel IGLESIAS, Alfonso FERNáNDEZ, Ana DE-JUAN, Ramón SANCIBRIáN, Pablo GARCíA
期刊论文
Eliminating mother-to-child transmission of HBV: progress and challenges in China
Wenzhan Jing, Jue Liu, Min Liu
期刊论文
An approach for evaluating the impact of an intermittent renewable energy source on transmission expansion
Rongrit CHATTHAWORN,Surachai CHAITUSANEY
期刊论文
Aerosol transmission, an indispensable route of COVID-19 spread: case study of a department-store cluster
期刊论文
Mass transport mechanisms within pervaporation membranes
Yimeng Song, Fusheng Pan, Ying Li, Kaidong Quan, Zhongyi Jiang
期刊论文
Interspecies transmission and evolution of the emerging coronaviruses: perspectives from bat physiology
Baicheng HUANG, Kegong TIAN
期刊论文