资源类型

期刊论文 436

会议视频 10

会议信息 1

会议专题 1

年份

2023 39

2022 57

2021 66

2020 29

2019 29

2018 31

2017 31

2016 34

2015 24

2014 8

2013 9

2012 9

2011 8

2010 7

2009 5

2008 4

2007 9

2006 8

2005 9

2004 5

展开 ︾

关键词

智能制造 4

复杂系统 3

2021全球十大工程成就 2

人工智能 2

信息物理融合系统 2

分布式系统 2

动态规划 2

复杂性 2

碳中和 2

神经网络 2

管理 2

系统工程 2

过程系统工程 2

鲁棒性 2

2R-1C模型；嵌入式系统；参数估计；非迭代方法；二次型 1

5G 1

9 + 2结构 1

Agent 1

展开 ︾

检索范围：

排序： 展示方式：

NEW ZEALAND DAIRY FARM SYSTEMS AND KEY ENVIRONMENTAL EFFECTS

Jiafa LUO, Stewart LEDGARD

《农业科学与工程前沿（英文）》 2021年 第8卷 第1期   页码 148-158 doi: 10.15302/J-FASE-2020372

摘要： This paper provides an overview of the range of dairy pasture grazing systems used in New Zealand (NZ), the changes with increased inputs over time and associated key environmental effects including nitrogen (N) leaching and greenhouse gas (GHG) emissions. NZ dairy farming systems are based on year-round grazing and seasonal milk production on perennial ryegrass/clover pasture where cows are rotationally grazed in paddocks. There was an increase in stocking rate on NZ dairy farms from 2.62 cows ha in 2000/2001 to 2.85 cows ha in 2015/2016. During the same period annual milk solids production increased from 315 to 378 kg·yr per cow. This performance has coincided with an increase in N fertilizer use (by 30%) and a twofold increase in externally-sourced feeds. Externally-sourced feeds with a low protein concentration (e.g., maize silage) can increase the efficiency of N utilization and potentially reduce N losses per unit of production. Off-paddock facilities (such as standoff or feed pads) are often used to restrict grazing during very wet winter conditions. A systems analysis of contrasting dairy farms in Waikato (largest NZ dairying region) indicates that the increased input would result in an increase in per-cow milk production but little change in efficiency of milk production from a total land use perspective. This analysis also shows that the increased inputs caused an 11% decrease in N footprint (i.e., N emissions per unit of milk production) and a 2% increase in C footprint (i.e., greenhouse gas (GHG) emissions per unit of milk production).

关键词： dairy farms     environmental impacts     grazing systems     intensification     mitigation    

HTML PDF 收藏

Error analysis of the parameters for non-coaxial grazing X-ray microscope

ZHAO Lingling, HU Jiasheng, LI Xiang

《机械工程前沿（英文）》 2007年 第2卷 第3期   页码 323-329 doi: 10.1007/s11465-007-0057-z

摘要： A non-coaxial grazing X-ray microscope, consisting of four spherical mirrors, is designed for diagnosis of inertial confinement fusion (ICF). The aberrations and imaging quality of the microscope are analyzed. To acquire excellent imaging quality, suitable tolerances for manufacturing and assembling the microscope are necessary. This paper researches the changes of Gauss parameters and aberrations due to component and subsystem parameters (such as the radius of the mirror, angle between mirrors, grazing angle, object distance, etc.). Here, spot diagrams and modulation transfer function (MTF) are first adopted to quantitatively evaluate the imaging quality of the microscope. Suitable manufacturing tolerances of components and assembly tolerances of the system are established on the basis of the discussion and analysis. A set of non-coaxial grazing X-ray microscopes is manufactured based on the tolerances. In site tests of ICF, the images with high resolution are obtained by the microscope.

关键词： non-coaxial     spherical     manufacturing     necessary     diagnosis    

HTML PDF 收藏

The ecological adaptability of cloned sheep to free-grazing in the Tengger Desert of Inner Mongolia,

Xinxin LI,Huijuan WANG,Guanghua SU,Zhuying WEI,Chunling BAI,Wuni-MENGHE,Yanhui HOU,Changqing YU,Shorgan BOU,Guangpeng LI

《农业科学与工程前沿（英文）》 2014年 第1卷 第3期   页码 191-200 doi: 10.15302/J-FASE-2014029

摘要： Since the birth of the first cloned sheep, somatic cell nuclear transfer technology has been successfully used to clone a variety of mammals. Cloned livestock have no apparent health risks, and the quality and safety of the cloned animal products are similar to non-cloned animals. The social behavior and environmental adaptability of postnatal cloned animals, especially when used for grassland farm production purposes, is unknown. In the present study, the cloned Dorper sheep equipped with GPS location devices were free-grazed in a harsh natural environment similar to conditions commonly experienced by Mongolian sheep. The main findings of this research were as follows. (1) Under free-grazing conditions, the cloned sheep showed excellent climatic and ecological adaptability. In extreme temperature conditions ranging from -30 to 40°C, the cloned sheep maintained acceptable body condition and behaved as other sheep. (2) The cloned sheep quickly adapted from a herd feeding strategy to the harsh environment and quickly exhibited a grazing regimen as other free-grazing sheep. (3) The cloned sheep exhibited free-grazing patterns and social behavior as other sheep. (4) The cloned sheep in the harsh environment thrived and produced healthy lambs. Overall, the cloned Dorper sheep exhibited excellent ecological adaptation, which is an important consideration for breeding meat sheep by cloning. The Dorper sheep readily adapted to the free-grazing conditions on the Mongolian plateau grassland, which attests to their ability to withstand harsh environmental conditions.

关键词： somatic cell nuclear transfer     free-grazing synchronization     Dorper sheep     cloned animal ecology    

HTML PDF 收藏

我国草原生产力

侯扶江,王春梅,娄珊宁,侯向阳,呼天明

《中国工程科学》 2016年 第18卷 第1期   页码 80-93 doi: 10.15302/J-SSCAE-2016.01.011

摘要：

分析我国草原植物生产和动物生产，比较国内外草原生产力。结果表明，在过去的30余年中，我国一部分草原产草量下降，局部变化不显著。世界草原对畜产品生产的贡献率为40.08 %，中等收入国家为67.35 %。全球24.1 %的牛肉和31.9 %的羊肉来自草原，低收入国家草原载畜量分别高出高收入国家和中等收入国家87.4 %和66.4 %，畜产品生产分别只有两者的37.3 %和71.9 %。适宜的放牧利用，可使我国的草原生产能力达到6.35×109畜产品单位（APU）；全国草原单纯依靠放牧每年可产肉2.959×106 t，占全国肉类总产量的3.5 %，占全国牛羊肉总产量的27.4 %。通过草原畜牧业的现代化转型可接近高收入国家水平，增产潜力约为50 %~200 %。

关键词： 草原生产力     产草量     放牧     载畜量     畜产品单位（APU）    

HTML PDF 收藏

Integrating space and time: a case for phenological context in grazing studies and management

Dawn M. BROWNING, Sheri SPIEGAL, Richard E. ESTELL, Andres F. CIBILS, Raul H. PEINETTI

《农业科学与工程前沿（英文）》 2018年 第5卷 第1期   页码 44-56 doi: 10.15302/J-FASE-2017193

摘要： In water-limited landscapes, patterns in primary production are highly variable across space and time. Livestock grazing is a common agricultural practice worldwide and a concern is localized overuse of specific pasture resources that can exacerbate grass losses and soil erosion. On a research ranch in New Mexico with average annual rainfall of 217 mm, we demonstrate with a quantitative approach that annual seasons vary greatly and examine foraging patterns in Angus-Hereford ( ) cows. We define five seasonal stages based on MODIS NDVI: pre-greenup, greenup, peak green, drydown and dormant, and examine livestock movements in 2008. Daily distance traveled by cows was greater and foraging area expanded during periods with higher precipitation. A regression model including minimum NDVI, rainfall and their interaction explained 81% of the seasonal variation in distance traveled by cows ( <0.01). Cows explored about 81 ha·d while foraging, but tended to explore smaller areas as the pasture became greener (greenup and peak green stages). Cows foraged an average of 9.7 h daily and spent more time foraging with more concentrated search patterns as pastures became greener. Our findings suggest that phenological context can expand the capacity to compare and integrate findings, and facilitate meta-analyses of grazing studies conducted at different locations and times of year.

关键词： GPS collars     Jornada Experimental Range     land-surface phenology     livestock movement     LTAR     MODIS NDVI     rangeland    

HTML PDF 收藏

利用六氟化硫示踪技术预估不同年龄阶段的放牧荷斯坦奶牛甲烷排放量

Steven J. Morrison, Judith McBride, Alan W. Gordon, Alastair R. G. Wylie, 闫天海

《工程（英文）》 2017年 第3卷 第5期   页码 753-759 doi: 10.1016/J.ENG.2017.03.018

摘要：

动物和日粮因素对牛肠道甲烷排放量影响的相关研究已经很普遍，但是关于放牧青年奶牛的甲烷排放量的可参考数据较少。本研究评估了荷斯坦奶牛在多年生黑麦草草地放牧时的生理状态对甲烷排放量的影响，分别进行了以下两个试验：试验1从2011年5月开始，为期11个星期，试验2从2011年8月开始，为期10个星期。在每个试验中，将荷斯坦奶牛分成三个处理组（每组12头），分别由小牛犊、一岁的母牛犊和妊娠母牛组成（平均年龄分别为8.5、14.5和20.5月龄）。在每个试验的最后一个星期利用六氟化硫示踪技术预估每头牛的甲烷排放量。干物质摄入量由代谢能需要量除以牧草中的代谢能含量计算而得。正如预期一样，活体重随年龄的增加而增加（P < 0.001），然而试验1中三个分组的体增重没有差异，试验2中的体增重随着年龄增加有不同程度的减少（P < 0.001）。在试验1中，妊娠母牛高于小牛犊的甲烷排放量（P < 0.001），而一岁母牛犊的甲烷排放量最高（g•d－1）。当用单位活体重、干物质摄入量和总能摄入量表示甲烷排放量时，一岁母牛犊比小牛犊和妊娠母牛的排放速率更高（P < 0.001）。在试验2中，甲烷排放量（g•d－1）随着年龄增加呈线性上升（P < 0.001），但是这种差异在一岁母牛犊和妊娠母牛中并不显著。妊娠母牛的甲烷/活体重的比值低于另外两组（P < 0.001），小牛犊的总能摄入量中甲烷能量输出的比值低于一岁母牛犊和妊娠母牛（P < 0.05）。根据所有数据建立甲烷排放量的预测方程。所有关系均为显著（P < 0.001），R²值的分布范围为0.630~0.682。这些模型表明：每增加1 kg活体重，甲烷排放量增加0.252 g•d－1；每增加1 kg•d－1干物质摄入量，甲烷排放量增加14.9 g•d－1；每增加1 MJ•d－1总能摄入量，甲烷能量输出增加0.046 MJ•d－1。当实际甲烷排放量不可测时，这些结果为我们提供了预估放牧母牛甲烷排放量的另一种方法。

关键词： 甲烷排放量     放牧奶牛     预测     六氟化硫示踪技术    

HTML PDF 收藏

Grassland ecology in China: perspectives and challenges

Deli WANG, Ling WANG, Jushan LIU, Hui ZHU, Zhiwei ZHONG

《农业科学与工程前沿（英文）》 2018年 第5卷 第1期   页码 24-43 doi: 10.15302/J-FASE-2018205

摘要： During the last few decades, there have been an increasing number of studies on grassland ecology in China, involving the classic ecology concepts or theories and the applicable ecological principles of grassland conservation or management. This paper reviews the main progress in the following aspects. (1) Research on grassland species adaptation and resistance, population dynamics and foraging behavior, and biodiversity and community stability. (2) Research on managed grassland ecosystems (grassland grazing ecology) including grazing effects on grassland ecosystem function and foraging behavior by large herbivores. (3) Global climate change and grassland processes and functioning. (4) Applied research on grassland restoration and ecosystem health assessments such as vegetation restoration, restoration of ecosystem functioning, and assessment methods. There have been significant advances in grassland ecology, including the functions of ecosystem biodiversity, the ecological stoichiometry mechanisms affecting grassland community stability, grazing regulation of plant diversity and nutrient cycling. Grassland ecologists have succeeded in making these advances through observational, experimental and theoretical studies. Nevertheless, there are still significant challenges for the grassland ecology research, including understanding of grassland spatial processes, grassland grazing and multi-functionality, integrated effects of global climate change across grassland areas, as well as the ecological methodology and experimental techniques in grassland ecology.

关键词： biodiversity     climate change     China     grazing     meadow     restoration     steppe    

HTML PDF 收藏

Grassland management practices in Chinese steppes impact productivity, diversity and the relationship

Yingjun ZHANG, Wenjie LU, Hao ZHANG, Jiqiong ZHOU, Yue SHEN

《农业科学与工程前沿（英文）》 2018年 第5卷 第1期   页码 57-63 doi: 10.15302/J-FASE-2017192

摘要： Grasslands are crucial parts of the terrestrial ecosystem, with an extremely high differentiation of productivity and diversity across spatial scales and land use patterns. The practices employed to manage grassland, such as grazing, haymaking, fertilization or reseeding, can improve the grassland condition. This study focuses on the changes in productivity and diversity and the relationship between them as affected by management practices. Productivity and diversity have unequivocally been altered in response to different management practices. When grazing intensity of a typical steppe increased from 1.5 to 9 sheep per hectare, both productivity and diversity declined. Higher grazing intensity (6 to 9 sheep per hectare) accelerated loss of diversity because of lower productivity. Productivity was significantly improved but diversity was lost by fertilizing. N fertilization also reduced the sensitivity of diversity to productivity. A similar response was found in mown grassland with increased productivity and diversity but their relationship was negatively affected. Mowing also slowed down the decline in diversity as productivity increased. Reseeding purple-flowered alfalfa led to an increased diversity, while yellow-flowered alfalfa increased productivity significantly. The negative productivity-diversity relationship was transformed to a positive one by reseeding alfalfa. These results enhance understanding of how productivity, diversity and their relationships change in response to altered grassland management practices, and support an integrated approach for improving both productivity and diversity.

关键词： diversity     fertilizing     grassland management practice     grazing     mowing     productivity     reseeding    

HTML PDF 收藏

LAND-USE INTENSIFICATION TRENDS IN THE RIO DE LA PLATA REGION OF SOUTH AMERICA: TOWARD SPECIALIZATION OR RECOUPLING CROP AND LIVESTOCK PRODUCTION

Paulo César DE FACCIO CARVALHO, Jean Víctor SAVIAN, Tomas DELLA CHIESA, William DE SOUZA FILHO, José Alfredo TERRA, Priscila PINTO, Amanda POSSELT MARTINS, Sebastian VILLARINO, Júlio Kuhn DA TRINDADE, Pedro Arthur DE ALBUQUERQUE NUNES, Gervasio PIÑEIRO

《农业科学与工程前沿（英文）》 2021年 第8卷 第1期   页码 97-110 doi: 10.15302/J-FASE-2020380

摘要： The Rio de la Plata region comprises central Argentina, Uruguay, and southern Brazil. Modern agriculture developed around 1900 with recent decades being characterized by the advance of cropping areas over native grasslands. Highly specialized agriculture has decoupled crop and livestock production but has succeeded in intensifying yields. However, significant losses of ecosystem services have been reported. Thus, questions have been raised on the sustainability of this pathway. A glance at world regions that have experienced similar trends suggests that an urgent course correction is needed. A major concern has been the lack of diversity in regions with highly specialized agriculture, promoting renewed interest in integrated crop-livestock systems (ICLS), not only because ICLS are more diverse than specialized systems, but also because they are rare examples of reconciliation between agroecosystem intensification and environmental quality. Consequently, this paper discusses alternatives to redesign multifunctional landscapes based on ICLS. Recent data provide evidence that recoupling crop and animal production increases the resilience of nutrient cycling functions and economic indicators to external stressors, enabling these systems to face climate-market uncertainty and reconcile food production with the provision of diverse ecosystem services. Finally, these concepts are exemplified in case studies where this perspective has been successfully applied.

关键词： grazing     integrated crop-livestock systems     mixed crops-livestock     Pampa    

HTML PDF 收藏

Current status and prospects of reliability systems engineering in China

《工程管理前沿（英文）》 2021年 第8卷 第4期   页码 492-502 doi: 10.1007/s42524-021-0172-2

摘要： This study provides a systematic overview of the advent and evolution of reliability systems engineering (RSE) in China, and the latest RSE development, that is, model-based RSE (MBRSE), is emphatically introduced. The establishment of the system architecture and conceptual models of MBRSE is first described. The fundamental theory and methodology of MBRSE are then elaborated, with a V-model as the core of this approach. The development of various MBRSE platforms and the effectiveness of their implementation over the past 30 years are presented. The prospective trends in the development of RSE in China are outlined.

关键词： reliability     effectiveness     model-based systems engineering     reliability systems engineering    

HTML PDF 收藏

Floating production storage and offloading systems’ cost and motion performance: A systems thinking application

Rini NISHANTH, Andrew WHYTE, V. John KURIAN

《工程管理前沿（英文）》 2018年 第5卷 第3期   页码 357-368 doi: 10.15302/J-FEM-2018022

摘要：

Floating production storage and offloading (FPSO) units increasingly represent a practical and economic means for deep-water oil extraction and production. Systems thinking gives a unique opportunity to seek a balance between FPSO technical performance(s), with whole-cost; stakeholder decision-making is charged to align different fit-for-use design specification options’ that address technical-motion(s), with respective life-cycle cost analyses (LCCA). Soft system methodology allows situation based analyses over set periods-of-time by diagnosing the problem-at-hand; namely, assessing the antecedents of life-cycle cost relative to FPSO sub-component design alternatives. Alternative mooring- component comparisons for either new-build hulls or refurbished hulls represent an initial necessary consideration to facilitate extraction, production and storage of deep-water oil reserves. Coupled dynamic analysis has been performed to generate FPSO motion in six degrees of freedom using SESAM DeepC, while life-cycle cost analysis (LCAA) studies give net-present-value comparisons reflective of market conditions. A parametric study has been conducted by varying wave heights from 4 – 8 m to understand FPSO motion behavior in the presence of wind and current, as well as comparing the motions of turreted versus spread mooring design alternatives. LCCA data has been generated to compare the cost of such different mooring options/hull conditions over 10 and 25-year periods. Systems thinking has been used to explain the interaction of problem variables; resultantly this paper is able to identify explicit factors affecting the choice of FPSO configurations in terms of motion and whole-cost, toward assisting significantly with the front-end engineering design (FEED) phase of fit-for-purpose configured FPSOs, in waters off Malaysia and Australia.

关键词： FPSO     LCCA     spread/turret-mooring     DeepC     cost     motion     soft-systems    

HTML PDF 收藏

TRANSFORMING CHINESE FOOD AND AGRICULTURE: A SYSTEMS PERSPECTIVE

《农业科学与工程前沿（英文）》 2023年 第10卷 第1期   页码 4-15 doi: 10.15302/J-FASE-2023493

摘要：

● The goals of Chinese food and agriculture have shifted from grain self-sufficiency to diversified goals, including protecting natural resources, reducing pollution and greenhouse gas emissions, and improving food safety and nutrition.

关键词： food systems     food security     nutrition     climate change    

HTML PDF 收藏

TRANSFORMATION OF FOOD SYSTEMS: HOW CAN IT BE FINANCED?

《农业科学与工程前沿（英文）》 2023年 第10卷 第1期   页码 109-123 doi: 10.15302/J-FASE-2023483

摘要：

● The analysis of financing for the transformation of food systems requires first a consideration of costs.

关键词： financial markets     food systems     development financing     consumer expenditures     public budgets     Sustainable Development Goals    

HTML PDF 收藏

Transition towards carbon-neutral electrical systems for China: Challenges and perspectives

《工程管理前沿（英文）》 2022年 第9卷 第3期   页码 504-508 doi: 10.1007/s42524-022-0220-6

关键词： carbon neutrality     power systems     electrification     renewable energy    

HTML PDF 收藏

Applying an Integrated Systems Perspective to the Management of Engineering Projects

Simon P. Philbin

《工程管理前沿（英文）》 2015年 第2卷 第1期   页码 19-30 doi: 10.15302/J-FEM-2015004

摘要： Engineering projects can be subject to significant complexity, which may result in a number of issues and challenges that need to be addressed throughout the project life-cycle. Traditionally projects have been viewed according to the so called “iron triangle,” i. e., achievement of project milestones according to schedule, cost and quality targets. While these targets are fundamentally important to the performance of engineering projects, it is possible to view projects on a systemic level in order to allow an adequate focus on all the underpinning factors that have the potential to influence the performance of projects. Consequently, a management framework has been developed that is based on an integrated systems perspective of engineering projects, where the performance of projects is a function of six contributing sub-systems that are: process, technology, resources, knowledge, culture and impact.

关键词： integrated systems perspective     engineering projects     management    

HTML PDF 收藏

标题 作者 时间 类型 操作

NEW ZEALAND DAIRY FARM SYSTEMS AND KEY ENVIRONMENTAL EFFECTS

Jiafa LUO, Stewart LEDGARD

期刊论文

Error analysis of the parameters for non-coaxial grazing X-ray microscope

ZHAO Lingling, HU Jiasheng, LI Xiang

期刊论文

The ecological adaptability of cloned sheep to free-grazing in the Tengger Desert of Inner Mongolia,

Xinxin LI,Huijuan WANG,Guanghua SU,Zhuying WEI,Chunling BAI,Wuni-MENGHE,Yanhui HOU,Changqing YU,Shorgan BOU,Guangpeng LI

期刊论文

我国草原生产力

侯扶江,王春梅,娄珊宁,侯向阳,呼天明

期刊论文

Integrating space and time: a case for phenological context in grazing studies and management

Dawn M. BROWNING, Sheri SPIEGAL, Richard E. ESTELL, Andres F. CIBILS, Raul H. PEINETTI

期刊论文

利用六氟化硫示踪技术预估不同年龄阶段的放牧荷斯坦奶牛甲烷排放量

Steven J. Morrison, Judith McBride, Alan W. Gordon, Alastair R. G. Wylie, 闫天海

期刊论文

Grassland ecology in China: perspectives and challenges

Deli WANG, Ling WANG, Jushan LIU, Hui ZHU, Zhiwei ZHONG

期刊论文

Grassland management practices in Chinese steppes impact productivity, diversity and the relationship

Yingjun ZHANG, Wenjie LU, Hao ZHANG, Jiqiong ZHOU, Yue SHEN

期刊论文

LAND-USE INTENSIFICATION TRENDS IN THE RIO DE LA PLATA REGION OF SOUTH AMERICA: TOWARD SPECIALIZATION OR RECOUPLING CROP AND LIVESTOCK PRODUCTION

Paulo César DE FACCIO CARVALHO, Jean Víctor SAVIAN, Tomas DELLA CHIESA, William DE SOUZA FILHO, José Alfredo TERRA, Priscila PINTO, Amanda POSSELT MARTINS, Sebastian VILLARINO, Júlio Kuhn DA TRINDADE, Pedro Arthur DE ALBUQUERQUE NUNES, Gervasio PIÑEIRO

期刊论文

Current status and prospects of reliability systems engineering in China

期刊论文

Floating production storage and offloading systems’ cost and motion performance: A systems thinking application

Rini NISHANTH, Andrew WHYTE, V. John KURIAN

期刊论文

TRANSFORMING CHINESE FOOD AND AGRICULTURE: A SYSTEMS PERSPECTIVE

期刊论文

TRANSFORMATION OF FOOD SYSTEMS: HOW CAN IT BE FINANCED?

期刊论文

Transition towards carbon-neutral electrical systems for China: Challenges and perspectives

期刊论文

Applying an Integrated Systems Perspective to the Management of Engineering Projects

Simon P. Philbin

期刊论文