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Meeting Expectations
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作者 Li Xiaoyang 《中国与非洲:英文版》 2019年第8期42-43,共2页
As it released data on Chinas economic performance in the first half (Hl) of 2019 on July 15, the National Bureau of Statistics (NBS) suggested that a solid foundation has been laid for the country to achieve its annu... As it released data on Chinas economic performance in the first half (Hl) of 2019 on July 15, the National Bureau of Statistics (NBS) suggested that a solid foundation has been laid for the country to achieve its annual growth targets as the economy maintained steady, resilient development. 展开更多
关键词 MEETING Expectations resilient DEVELOPMENT ECONOMIC PERFORMANCE
Effect of vertical stress rest period on deformation behaviour of unbound granular materials:Experimental and numerical investigations 预览
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作者 Ali Alnedawi Kali Prasad Nepal +1 位作者 Riyadh Al-Ameri Mohanad Alabdullah 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第1期172-180,共9页
Repeated load triaxial test is used to assess the deformation behaviour of unbound granular materials(UGMs)in flexible road pavements.Repeated load pulse characteristics(i.e.shape,loading period and rest period)are th... Repeated load triaxial test is used to assess the deformation behaviour of unbound granular materials(UGMs)in flexible road pavements.Repeated load pulse characteristics(i.e.shape,loading period and rest period)are the stress configurations used in the experimental set-up to simulate the passing axle loads.Some researchers and standard testing protocols suggest a rest period of varying durations after a loading phase.A thorough review of existing literature and practises has revealed that there is no agreement about the effect of the rest period of vertical stress pulse on the deformation behaviour of the UGMs.Therefore,the main objective of this study is to investigate the effect of repeated stress rest period on the deformation behaviour of UGMs experimentally.Experiments are conducted,both with and without rest period,using basalt and granite crushed rocks from Victoria,Australia.Furthermore,in order to gain insight into the effect of the rest period,finite element modelling is also developed.Both the experimental and modelling results show that the rest period has a noticeable effect on both resilient and permanent deformation behaviours of UGMs.It is,therefore,recommended to take extra precautions while adopting a particular standard testing protocol and to supplement the results by additional tests with different loading configurations. 展开更多
关键词 Flexible PAVEMENT Unbound GRANULAR materials(UGMs) Repeated load TRIAXIAL test Resilient MODULUS PERMANENT deformation Finite element modelling
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Cloud-based parallel power flow calculation using resilient distributed datasets and directed acyclic graph 预览
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作者 Dewen WANG Fangfang ZHOU Jiangman LI 《现代电力系统与清洁能源学报(英文)》 CSCD 2019年第1期65-77,共13页
With the integration of distributed generation and the construction of cross-regional long-distance power grids, power systems become larger and more complex.They require faster computing speed and better scalability ... With the integration of distributed generation and the construction of cross-regional long-distance power grids, power systems become larger and more complex.They require faster computing speed and better scalability for power flow calculations to support unit dispatch.Based on the analysis of a variety of parallelization methods, this paper deploys the large-scale power flow calculation task on a cloud computing platform using resilient distributed datasets(RDDs).It optimizes a directed acyclic graph that is stored in the RDDs to solve the low performance problem of the MapReduce model.This paper constructs and simulates a power flow calculation on a large-scale power system based on standard IEEE test data.Experiments are conducted on Spark cluster which is deployed as a cloud computing platform.They show that the advantages of this method are not obvious at small scale, but the performance is superior to the stand-alone model and the MapReduce model for large-scale calculations.In addition, running time will be reduced when adding cluster nodes.Although not tested under practical conditions, this paper provides a new way of thinking about parallel power flow calculations in large-scale power systems. 展开更多
关键词 Power flow calculation PARALLEL programming MODEL DISTRIBUTED memory-shared MODEL Resilient DISTRIBUTED datasets(RDDs) Directed ACYCLIC graph(DAG)
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Effect of freeze-thaw cycles on uniaxial mechanical properties of cohesive coarse-grained soils
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作者 QU Yong-long CHEN Guo-liang +3 位作者 NIU Fu-jun NI Wan-kui MU Yan-hu LUO Jing 《山地科学学报:英文版》 SCIE CSCD 2019年第9期2159-2170,共12页
Freeze-thaw cycles are closely related to the slope instability in high-altitude mountain regions. In this study, cohesive coarse-grained soils were collected from a high-altitude slope in the Qinghai–Tibet Plateau t... Freeze-thaw cycles are closely related to the slope instability in high-altitude mountain regions. In this study, cohesive coarse-grained soils were collected from a high-altitude slope in the Qinghai–Tibet Plateau to study the effect of cyclic freeze-thaw on their uniaxial mechanical properties. The soil specimens were remolded with three dry densities and three moisture contents. Then, after performing a series of freeze-thaw tests in a closed system without water supply, the soil specimens were subjected to a uniaxial compression test. The results showed that the stress-strain curves of the tested soils mainly performed as strain-softening. The softening feature intensified with the increasing dry density but weakened with an increase in freeze-thaw cycles and moisture content. The uniaxial compressive strength, resilient modulus, residual strength and softening modulus decreased considerably with the increase of freeze-thaw cycles. After more than nine freeze-thaw cycles, these four parameters tended to be stable. These parameters increased with the increase of dry density and decreased with the increasing moisture content, except for the residual strength which did not exhibit any clear variation with an increase in moisture content. The residual strength, however, generally increased with an increase in dry density. The soil structural damage caused by frozen water expansion during the freeze-thaw is the major cause for the changes in mechanical behaviors of cohesive coarse-grained soils. With results in this study, the deterioration effect of freeze-thaw cycles on the mechanical properties of soils should be considered during the slope stability analysis in high-altitude mountain regions. 展开更多
关键词 Freeze thaw cycles Residual STRENGTH Resilient MODULUS SOFTENING MODULUS UNIAXIAL COMPRESSIVE STRENGTH Slope stability
Composite anti-disturbance resilient control for Markovian jump nonlinear systems with general uncertain transition rate
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作者 Guangdeng ZONG Yankai LI Haibin SUN 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第2期97-114,共18页
In this paper,the issue of disturbance observer based resilient control is addressed for Markovian jump nonlinear systems with multiple disturbances and general uncertain transition rates.The disturbances are divided ... In this paper,the issue of disturbance observer based resilient control is addressed for Markovian jump nonlinear systems with multiple disturbances and general uncertain transition rates.The disturbances are divided into two parts:one has a bounded H2 norm,and the other is given by an exogenous system.The general uncertain transition rate matrix is composed of unknown elements and uncertain ones.The uncertain transition rate only has a known approximate range.First,the disturbance described by the exogenous system is estimated by a disturbance observer,and its estimation is used for the controller as feedforward compensation.Subsequently,by using the resilient control method,a composite anti-disturbance resilient controller is constructed to guarantee stochastic stability with L2-L∞ performance of the closed-loop systems.Subsequently,the Lyapunov stability method and linear matrix inequality technique are applied to obtain the controller gain.Finally,an application example is provided to illustrate the effectiveness of the proposed approach. 展开更多
关键词 COMPOSITE ANTI-DISTURBANCE control resilient CONTROLLER Markovian JUMP nonlinear systems general UNCERTAIN transition probabilities multiple disturbances L2-L∞ performance
MEETING EXPECTATIONS
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作者 Li Xiaoyang 《北京周报:英文版》 2019年第30期12-15,共4页
As it released data on China's economic performance in the first half (H1) of 2019 on July 15, the National Bureau of Statistics (NBS) suggested that a solid foundation has been laid for the country to achieve its... As it released data on China's economic performance in the first half (H1) of 2019 on July 15, the National Bureau of Statistics (NBS) suggested that a solid foundation has been laid for the country to achieve its annual growth targets as the economy maintained steady, resilient development. 展开更多
关键词 ECONOMIC PERFORMANCE NBS resilient
Characteristics of Vibration and Sound Radiation of Metro Resilient Wheel
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作者 Xin Zhou Jian Han +4 位作者 Yue Zhao Bing Wu Gong Cheng Shenghui Xu Xuesong Jin 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第4期195-206,共12页
Resilient wheels are extensively used in urban rail transit, especially for tramway systems, owing to its advantages in noise reduction. A new type of resilient wheel for a metro is designed, and its characteristics o... Resilient wheels are extensively used in urban rail transit, especially for tramway systems, owing to its advantages in noise reduction. A new type of resilient wheel for a metro is designed, and its characteristics of vibration and sound radiation, including the rolling noise of a resilient single wheel coupled with a track, are studied in this paper. A two-step research is presented. Firstly, laboratory experiments were conducted to obtain the vibration response of the designed resilient wheel under the radial excitation on its tread. Secondly, the rolling noise model of the resilient wheel coupled with a slab track used in a metro line is developed. The wheel model is based on the 3 D finite elementand boundary element methods and verified by using the experimental results obtained from the laboratory. The track vibration model is based on the wavenumber finite element method, and the track sound radiation is calculatedby using an e cient frequency-domain Rayleigh method. The interaction of the resilient wheel and the slab track is analyzed considering the measured wheel/rail roughness of the metro. The contribution of the resilient wheel to the reduction of wheel/rail system noise is analyzed. The results show that the resilient wheel can e ectively reduce the wheel/rail rolling noise by approximately 2 dB(A) to 3 dB(A), mainly because the radiated noise by the rail is reduced. In addition, the elastic modulus of the rubber has an important influence on the noise reduction of resilient wheels. 展开更多
关键词 Resilient WHEEL WHEEL/RAIL ROLLING noise Noise reduction Laboratory experiment FINITE ELEMENT and boundary ELEMENT methods
High-Speed Trains Automatic Operation with Protection Constraints:A Resilient Nonlinear Gain-based Feedback Control Approach 预览
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作者 Shigen Gao Yuhan Hou +2 位作者 Hairong Dong Sebastian Stichel Bin Ning 《自动化学报:英文版》 CSCD 2019年第4期992-999,共8页
This paper addresses the control design for automatic train operation of high-speed trains with protection constraints.A new resilient nonlinear gain-based feedback control approach is proposed,which is capable of gua... This paper addresses the control design for automatic train operation of high-speed trains with protection constraints.A new resilient nonlinear gain-based feedback control approach is proposed,which is capable of guaranteeing,under some proper non-restrictive initial conditions,the protection constraints control raised by the distance-to-go(moving authority)curve and automatic train protection in practice.A new hyperbolic tangent function-based model is presented to mimic the whole operation process of high-speed trains.The proposed feedback control methods are easily implementable and computationally inexpensive because the presence of only two feedback gains guarantee satisfactory tracking performance and closed-loop stability,no adaptations of unknown parameters,function approximation of unknown nonlinearities,and attenuation of external disturbances in the proposed control strategies.Finally,rigorous proofs and comparative simulation results are given to demonstrate the effectiveness of the proposed approaches. 展开更多
关键词 AUTOMATIC TRAIN operation high-speed TRAIN nonlinear GAIN feedback PROTECTION CONSTRAINT resilient control
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Resilient modulus prediction of soft low-plasticity Piedmont residual soil using dynamic cone penetrometer 预览
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作者 S.Hamed Mousavi Mohammed A.Gabr Roy H.Borden 《岩石力学与岩土工程学报:英文版》 CSCD 2018年第2期323-332,共10页
Dynamic cone penetrometer(DCP)has been used for decades to estimate the shear strength and stiffness properties of the subgrade soils.There are several empirical correlations in the literature to predict the resilient... Dynamic cone penetrometer(DCP)has been used for decades to estimate the shear strength and stiffness properties of the subgrade soils.There are several empirical correlations in the literature to predict the resilient modulus values at only a specific stress state from DCP data,corresponding to the predefined thicknesses of pavement layers(a 50 mm asphalt wearing course,a 100 mm asphalt binder course and a 200 mm aggregate base course).In this study,field-measured DCP data were utilized to estimate the resilient modulus of low-plasticity subgrade Piedmont residual soil.Piedmont residual soils are in-place weathered soils from igneous and metamorphic rocks,as opposed to transported or compacted soils.Hence the existing empirical correlations might not be applicable for these soils.An experimental programwas conducted incorporating field DCP and laboratory resilient modulus tests on“undisturbed”soil specimens.The DCP tests were carried out at various locations in four test sections to evaluate subgrade stiffness variation laterally and with depth.Laboratory resilient modulus test results were analyzed in the context of the mechanistic-empirical pavement design guide(MEPDG)recommended universal constitutive model.A new approach for predicting the resilient modulus from DCP by estimating MEPDG constitutive model coefficients(k1,k2 and k3)was developed through statistical analyses.The new model is capable of not only taking into account the in situ soil condition on the basis of field measurements,but also representing the resilient modulus at any stress state which addresses a limitation with existing empirical DCP models and its applicability for a specific case.Validation of the model is demonstrated by using data that were not used for model development,as well as data reported in the literature. 展开更多
关键词 DYNAMIC cone penetrometer(DCP) Resilient modulus Mechanistic-empirical pavement design guide(MEPDG) Residual SOILS SUBGRADE SOILS
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公共治理视阈下小城镇韧性发展研究 预览
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作者 郭文娟 《山西农业大学学报:社会科学版》 2018年第9期42-47,共6页
小城镇之路是国家新型城镇化的重要空间战略,良好的公共治理秩序是小城镇韧性发展的保障。当前小城镇公共治理格局下规划不科学、公共服务供求不匹配、市场竞争低效、社区组织松散导致“社会——生态”系统的工程、社会、经济、社区等... 小城镇之路是国家新型城镇化的重要空间战略,良好的公共治理秩序是小城镇韧性发展的保障。当前小城镇公共治理格局下规划不科学、公共服务供求不匹配、市场竞争低效、社区组织松散导致“社会——生态”系统的工程、社会、经济、社区等脆弱性危机,影响小城镇韧性发展。从现代公共治理逻辑入手,认为多元治理主体角色错位、越位、缺位,社会资本公共价值租值耗散是症结所在。厘清小城镇公共治理中多元主体角色边界和合作关系,提出小城镇韧性发展路径,是推进新型城镇化、培育乡村振兴增长极、实现全面小康的重要方面。 展开更多
关键词 小城镇 脆弱性 韧性 公共治理
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A Construction of 1-Resilient Boolean Functions with Good Cryptographic Properties
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作者 SHAN Jinyong HU Lei +1 位作者 ZENG Xiangyong LI Chunlei 《系统科学与复杂性学报:英文版》 SCIE EI CSCD 2018年第4期1042-1064,共23页
关键词 构造 性质 密码 代数学 非线性 布尔函数 修改 连续性
可恢复功能的装配式预应力钢框架性能化设计研究 被引量:4
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作者 张艳霞 张贺昕 +1 位作者 刘安然 李振兴 《建筑钢结构进展》 CSCD 北大核心 2017年第4期1-9,共9页
针对提出的可恢复功能的装配式预应力钢框架结构体系,依据已完成的梁柱节点、框架试验和整体结构的分析结果,结合我国现行建筑抗震设计规范,提出了腹板摩擦耗能的可恢复功能的装配式预应力钢框架"多遇地震无开口、无损伤,设防地震开口... 针对提出的可恢复功能的装配式预应力钢框架结构体系,依据已完成的梁柱节点、框架试验和整体结构的分析结果,结合我国现行建筑抗震设计规范,提出了腹板摩擦耗能的可恢复功能的装配式预应力钢框架"多遇地震无开口、无损伤,设防地震开口耗能且主体结构无损伤、罕遇地震主体结构损伤较小且仍能正常使用"的性能化设计目标,同时提出了性能化设计准则和设计流程,并通过设计算例验证了该方法的可行性,证明了提出的装配式预应力钢框架的结构响应估算方法具有一定的可靠性。 展开更多
关键词 可恢复功能的 装配式预应力钢框架 腹板摩擦耗能 性能化设计目标 性能化设计准则 设计流程
Participatory Early Warning Systems: Youth, Citizen Science,and Intergenerational Dialogues on Disaster Risk Reduction in Brazil
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作者 Victor Marchezini Rachel Trajber +3 位作者 De′bora Olivato Viviana Aguilar Mun?oz Fernando de Oliveira Pereira Andre′a Eliza Oliveira Luz 《国际灾害风险科学学报:英文版》 CSCD 2017年第4期390-401,共12页
Building national people-centered early warning systems(EWS) is strongly recommended by the United Nations International Strategy for Disaster Reduction(UNISDR). Most of the scientific literature is critical of the co... Building national people-centered early warning systems(EWS) is strongly recommended by the United Nations International Strategy for Disaster Reduction(UNISDR). Most of the scientific literature is critical of the conventional view of EWS as a linear model with a topdown approach, in which technological features are given more attention than human factors. It is argued that EWS should be people-centered, and used for risk prevention,with an emphasis on resilience, rather than only being triggered when a hazard occurs. However, both the UNISDR and the literature fail to say how a people-centered EWS should be built, and what steps are needed to put EWS into effect. This article examines the obstacles and measures required to promote people-centered EWS,with a focus on the situation in Brazil. After assessing the institutional vulnerability of EWS, we analyze some measures that can be taken to reduce institutional vulnerability,based on experiences with a participatory citizen science educational project that involved high school students.Some guidelines are developed for adopting a bottom-up approach towards achieving the four elements of EWS—risk knowledge, monitoring, communication of warnings,and response capability—with the help of school curricula. 展开更多
关键词 Brazil Capacity building CITIZEN science Disaster risk reduction Early WARNING systems Resilient SCHOOLS
大巴黎规划国际咨询中“都市农业”设计思想探析 预览
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作者 郑婕 吴坡 +1 位作者 张玉坤 张睿 《建筑节能》 CAS 2017年第7期52-55,共4页
大巴黎规划国际咨询会是在《京都议定书》之后,首次以解决大都市问题、探讨城市的可持续发展方式为中心的设计研究盛会。参会的规划师、建筑师们从促进城乡融合、加强景观与环境的连续性、减少相关资源消耗、实现食物的自给自足等不同... 大巴黎规划国际咨询会是在《京都议定书》之后,首次以解决大都市问题、探讨城市的可持续发展方式为中心的设计研究盛会。参会的规划师、建筑师们从促进城乡融合、加强景观与环境的连续性、减少相关资源消耗、实现食物的自给自足等不同角度出发,不约而同地都采用了都市农业设计策略。这些成果可为我国城镇化规划建设提供有益思路与借鉴。通过案例分析与归纳,总结各方案在实施都市农业策略过程中所采用的形式操作手法,以及处理相关环境、经济与社会问题的措施。借鉴大巴黎国际咨询的成果,提出在我国发展都市农业的步骤与原则。 展开更多
关键词 都市农业 大巴黎规划 生态城市 弹性
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现代电网的六个基本特性 预览 被引量:1
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作者 Don Tan Damir Novosel 《南方电网技术》 北大核心 2017年第10期2-9,共8页
最近的研究表明,世界人口和人均能源消费量在2050年将翻一番。与此同时,根据最近的报告电网正在老化。这就体现出电网现代化的强大动力、必要性和机遇。电网现代化意味着消费者、电网运营商/机构及环境是三赢局面。本文讨论了现代电... 最近的研究表明,世界人口和人均能源消费量在2050年将翻一番。与此同时,根据最近的报告电网正在老化。这就体现出电网现代化的强大动力、必要性和机遇。电网现代化意味着消费者、电网运营商/机构及环境是三赢局面。本文讨论了现代电网的六个基本特性:电子、分形、结构化、容错、弹性和异步。本文提出了一种独特可行的现代电网架构,可通过目前先进的技术实现。我们可以利用先进的电力电子与系统技术在发电、输电、配电和离网储能等方面以最优的管理手段来迎接世界对能源需求的挑战。 展开更多
关键词 现代电网 电力电子与系统技术 微电网 电子 分形 结构化 吝错 弹性 异步
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聚丙烯树脂不同类型的选用对药用聚丙烯瓶性能的影响 预览
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作者 张思远 《塑料包装》 CAS 2017年第3期54-57,共4页
比较不同类型聚丙烯树脂以及所制成的塑料瓶的检验结果,选用其中两种牌号的聚丙烯树脂进行配方组合,选取合适的配合比例,以期得到聚丙烯瓶的性能指标符合药用聚丙烯瓶的标准要求。通过5个牌号的聚丙烯树脂的选用,并按不同比例的配... 比较不同类型聚丙烯树脂以及所制成的塑料瓶的检验结果,选用其中两种牌号的聚丙烯树脂进行配方组合,选取合适的配合比例,以期得到聚丙烯瓶的性能指标符合药用聚丙烯瓶的标准要求。通过5个牌号的聚丙烯树脂的选用,并按不同比例的配方进行100mlPP瓶生产,经对100mlPP瓶理化检测,筛选出符合要求的配方,并找出聚丙烯树脂理化指标与瓶子理化指标的相关性。聚丙烯树脂的正己烷溶出物、IZOD耐冲击强度与聚丙烯塑料瓶的正己烷溶出物、抗跌性正相关,同类型聚丙烯的熔体流动速率(MRF)与“IZOD耐冲击强度”负相关,采用不同类型的聚丙烯树脂经合适的配比可以得到符合YBB00082002-2015标准的聚丙烯塑料瓶 展开更多
关键词 聚丙烯树脂 聚丙烯塑料瓶 正己烷溶出物 抗跌性 IZOD耐冲击强度 YBB00082002-2015标准
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走向美好城市的六大战略 被引量:1
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作者 约翰·弗里德曼(著) 冯革群(译) 《国际城市规划》 CSSCI 北大核心 2015年第6期1-4,共4页
为了建立一个更公平、宜居的城市世界,本文提出六个实现美好城市的战略:(1)学会生活在一个物质资源有限的世界(有限度的世界)之中;(2)致力于发展生态可持续和韧性的城市;(3)优先发展地方经济,并着眼于满足人的基本需求;(... 为了建立一个更公平、宜居的城市世界,本文提出六个实现美好城市的战略:(1)学会生活在一个物质资源有限的世界(有限度的世界)之中;(2)致力于发展生态可持续和韧性的城市;(3)优先发展地方经济,并着眼于满足人的基本需求;(4)设计一种核算体系,将使用价值的生产与具有市场价值的商品和服务的生产视作同等重要,而使用价值的直接生产更有利于宜居城市的发展;(5)通过培育城市精神,培养多元文化,打造差异社区和保护市民组织来创建富有活力的城市;(6)重建公民道德,并将其作为地方自治的品牌亮点,通过协商行动致力于营造富有活力的宜居城市空间。 展开更多
关键词 有限度的世界 生态可持续 韧性 国民核算体系 富有活力的宜居城市
Proposal of a Conceptual Model to Analyse the Influence of LARG Practices on Manufacturing Supply Chain Performance 预览 被引量:1
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作者 Susana G. Azevedo Helena Carvalho V. Cruz-Machado 《现代会计与审计》 2012年第2期 174-184,共11页
关键词 供应链管理 模型分析 制造业 绩效 环保性能 概念模型 测量系统 经营业绩
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浅谈强夯置换法在处理粉煤灰路基中的应用 预览
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作者 张照新 《城市道桥与防洪》 2011年第7期 192-193,208,共3页
以热电厂沉淀池粉煤灰段作为路基的处理方法在软地基处理中的应用在兰州地区尚属首例。在确保工程质量、确保工程工期、并最大可能地节省工程投资的前提下,尝试性地采用强夯换置法对粉煤灰段进行软基处理施工,取得了良好的社会效益和经... 以热电厂沉淀池粉煤灰段作为路基的处理方法在软地基处理中的应用在兰州地区尚属首例。在确保工程质量、确保工程工期、并最大可能地节省工程投资的前提下,尝试性地采用强夯换置法对粉煤灰段进行软基处理施工,取得了良好的社会效益和经济效益,相关经验可供类似工程参考。 展开更多
关键词 强夯置换 粉煤灰 静载试验 回弹模量 动力触探
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提高供应链柔性途径研究 预览 被引量:5
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作者 黄尚海 《物流科技》 2010年第1期 81-84,共4页
通过分析供应链风险产生的原因,企业可以通过提高供应链的柔性去降低供应链风险。有两种途径来达到这个目标:一是通过相关的措施来降低脆弱性;二是通过企业有效的反应来降低冲击产生的影响,从断裂中迅速恢复过来。
关键词 脆弱性 柔性 供应链风险 灵活性
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