资源类型

期刊论文 1020

年份

2023 72

2022 79

2021 66

2020 75

2019 50

2018 43

2017 44

2016 43

2015 49

2014 50

2013 39

2012 41

2011 39

2010 46

2009 47

2008 39

2007 36

2006 28

2005 27

2004 26

展开 ︾

关键词

数学模型 13

模型试验 9

数值模拟 8

模型 7

COVID-19 4

不确定性 4

GM(1 3

计算机模拟 3

1)模型 2

DX桩 2

D区 2

Preissmann格式 2

SARS 2

TRIZ 2

Weibull分布 2

k-ε模型 2

临震信号 2

云模型 2

人员疏散 2

展开 ︾

检索范围：

排序： 展示方式：

Analysis of synergy degree and its influencing factors in hydropower EPC project management

Jiwei ZHU, Hua GAO, Jiangrui WANG

《工程管理前沿（英文）》 2021年 第8卷 第3期   页码 402-411 doi: 10.1007/s42524-020-0098-0

摘要： The use of engineering procurement construction (EPC) mode is currently a trend in hydropower engineering construction. The clarification of the internal relationship between hydropower EPC projects and the realization of synergy has great significance in improving management efficiency and implementation effect. In this work, a three-dimensional system and a system model of hydropower EPC project management synergy are constructed. The mechanism and factors that influence the degree of management synergy are analyzed on the basis of management synergy theory. Furthermore, the evaluation index system and the degree of synergy model are established, and grey relational analysis is utilized to identify the key factors that affect the synergy degree. Thus, this study aims to facilitate the hydropower EPC project management synergy, provide a quantitative method for synergy degree evaluation, and propose corresponding promotion strategies. Results show that the order degree of each subsystem presents a steady upward trend. Specifically, the order degree of the subsystem at the trial operation stage is low, which is the major restriction on the further improvement of the synergy degree of EPC project management. The key factors in improving the synergy level of hydropower EPC project management are mainly concentrated in the information and organization synergy subsystems, including the construction degree of information platform, the performance of functions, the timeliness of information transfer, and the functions of the information platform.

关键词： hydropower project     EPC mode     synergy degree model     grey relational analysis    

HTML PDF 收藏

Effect of fiber hybridization on energy absorption and synergy in concrete

Ahmadreza RAMEZANI, Mohammad Reza ESFAHANI

《结构与土木工程前沿（英文）》 2019年 第13卷 第6期   页码 1338-1349 doi: 10.1007/s17009-019-0558-2

摘要： In the present study, steel and polypropylene (PP) fibers have been utilized with the intent of obtaining hybrid fiber-reinforced concrete (HFRC) with desirable mechanical properties. An attempt has been made to scrutinize the properties of HFRC with the main concentration being on energy absorption characteristics of concrete and the efficacy of fiber hybridization in producing synergy. Accordingly, a total of 180 specimens, representing 20 different mixtures have been cast and evaluated through compressive, split tensile, and flexural tests. The relevant flexural toughness of the specimens was calculated using ASTM C1018, ASTM C1609, JSCE, and PCS methods, and the effectiveness of these methods was evaluated based on the experimental results. It was observed that steel fibers are more effective in the improvement of flexural toughness in the presence of PP fibers. Furthermore, synergy associated with the combination of fibers at different stages of deflection of the beam specimens was observed and analyzed.

关键词： hybrid fiber-reinforced concrete     synergy     toughness     steel fibers     polypropylene fibers    

HTML PDF 收藏

Numerical analysis on heat transfer enhancement by longitudinal vortex based on field synergy principle

WU Junmei, TAO Wenquan

《能源前沿（英文）》 2007年 第1卷 第3期   页码 365-369 doi: 10.1007/s11708-007-0055-1

摘要： Three-dimensional numerical simulation results are presented for a fin-and-tube heat transfer surface with vortex generators. The effects of the Reynolds number (from 800 to 2 000) and the attack angle (30º and 45º) of a delta winglet vortex generator are examined. The numerical results are analyzed on the basis of the field synergy principle to explain the inherent mechanism of heat transfer enhancement by longitudinal vortex. The secondary flow generated by the vortex generators causes the reduction of the intersection angle between the velocity and fluid temperature gradients. In addition, the computational evaluations indicate that the heat transfer enhancement of delta winglet pairs for an aligned tube bank fin-and-tube surface is more significant than that for a staggered tube bank fin-and-tube surface. The heat transfer enhancement of the delta winglet pairs with an attack angle of 45º is larger than that with an angle of 30º. The delta winglet pair with an attack angle of 45º leads to an increase in pressure drop, while the delta winglet pair with the 30º angle results in a slight decrease. The heat transfer enhancement under identical pumping power condition for the attack angle of 30º is larger than that for the attack angle of 45º either for staggered or for aligned tube bank arrangement.

关键词： computational     inherent mechanism     staggered     decrease     transfer surface    

HTML PDF 收藏

论正态云模型的普适性

李德毅,刘常昱

《中国工程科学》 2004年 第6卷 第8期   页码 28-34

摘要：

分布函数是分析随机现象的重要工具，正态分布是最重要的概率分布，在自然科学和社会科学中应用广泛；隶属函数是模糊集合的基石，正态隶属函数也有广泛的应用。但是，精确确定一个模糊概念的隶属函数已经成为模糊学应用的瓶颈。云模型把随机性和模糊性结合起来，用数字特征熵，揭示随机性与模糊性的关联性，并用来表示一个定性概念的粒度。正态云模型通过期望、熵和超熵构成的特定结构发生器，生成定性概念的定量转换值，体现概念的不确定性。这种特定结构不但放宽了形成正态分布的前提条件，而且把精确确定隶属函数放宽到构造正态隶属度分布的期望函数，因而更具有普遍适用性，更简单、直接地完成了定性与定量之间的相互转换过程。

关键词： 正态分布函数     隶属度     正态云模型     概念粒度     普适性    

HTML PDF 收藏

Enhanced synergy between Cu

Jingwei Zhang, Lingxin Kong, Yao Chen, Huijiang Huang, Huanhuan Zhang, Yaqi Yao, Yuxi Xu, Yan Xu, Shengping Wang, Xinbin Ma, Yujun Zhao

《化学科学与工程前沿（英文）》 2021年 第15卷 第3期   页码 666-678 doi: 10.1007/s11705-020-1982-1

摘要： As the substitution of common noble catalysts in the hydrogenation of carboxylic acid, a highly effective Cu-Ni/SiO catalyst was prepared by a novel stepwise ammonia evaporation method. Its performance in the gas-phase hydrogenation of acetic acid was further examined. With the introduction of Ni dopant, more stable Cu sites, which can adsorb more acetic acid, were formed due to the electron transfer from Cu to Ni. This makes more Cu sites available for hydrogen adsorption, which was suggested as the rate-determining step in acetic acid hydrogenation. A conversion of 99.6% was successfully achieved on this new Cu/SiO -0.5Ni catalyst, accompanied by the ethanol selectivity of 90%. The incorporation of nickel between copper nanoparticles enhances the synergistic effect between Cu and Cu . It also helps mitigate the aggregation of copper nanoparticles due to the Ostwald ripening effect induced by acetic acid and enhance the stability of copper catalyst in the conversion of carboxylic acid.

关键词： carboxylic acid     hydrogenation     copper     nickel     stability    

HTML PDF 收藏

An Evaluation Model for the Coordinated Development of a Circular Economy in China and Its Application

Ji-liang Zheng,Chen Zheng,Pan Chen,Ching Yuan Luk

《工程管理前沿（英文）》 2014年 第1卷 第4期   页码 364-371 doi: 10.15302/J-FEM-2014053

摘要： Energy-intensive industries (EIIs) are fundamental to the industrial development of China and are also the key industries of a circular economic infrastructure. It is worth paying attention to the coordinated development of a circular economy using EIIs due to the present interrelationship among EIIs. It is related to the optimization and comprehensive performance improvement of a circular economy. Based on the perspective of order parameter, this study uses economic and environmental subsystems to establish an evaluation model that examines the coordinated development of a circular economy within six main EIIs and an EII cluster from 2006 to 2011 in China. The result shows that the level of coordinated development in a circular economy among six EIIs differs and the level of coordinated development of circular economy among the EII cluster lags behind that of each EII examined. It also shows that the outside coordinated degree of EIIs is lower than the inside coordinated degree of each EII.

关键词： order parameter     coordinated degree evaluation     energy-intensive industry     circular economy    

HTML PDF 收藏

Homoharringtonine synergy with oridonin in treatment of t(8; 21) acute myeloid leukemia

Weina Zhang, Ying Lu, Tao Zhen, Xinjie Chen, Ming Zhang, Ping Liu, Xiangqin Weng, Bing Chen, Yueying Wang

《医学前沿（英文）》 2019年 第13卷 第3期   页码 388-397 doi: 10.1007/s11684-018-0624-1

摘要： Collaboration of c-KIT mutations with AML1–ETO (AE) has been demonstrated to induce t(8; 21) acute myeloid leukemia (AML). Targeted therapies designed to eliminate AE and c-KIT oncoproteins may facilitate effective treatment of t(8; 21) AML. Homoharringtonine (HHT) features activity against tumor cells harboring c-KIT mutations, whereas oridonin can induce t(8; 21) AML cell apoptosis and AE cleavage. Therefore, studies should explore the efficacy of combination therapy with oridonin and HHT in t(8; 21) AML. In this study, we investigated the synergistic effects and mechanism of oridonin combined with HHT in t(8; 21) AML cell line and mouse model. The two drugs synergistically inhibited cell viability and induced significant mitochondrial membrane potential loss and apoptosis. Oridonin and HHT induced significant downregulation of c-KIT and its downstream signaling pathways and promoted AE cleavage. HHT increased intracellular oridonin concentration by modulating the expressions of MRP1 and MDR1, thus enhancing the effects of oridonin. The combination of oridonin and HHT prolonged t(8; 21) leukemia mouse survival. In conclusion, oridonin and HHT exert synergistic effects against t(8; 21) leukemia and , thereby indicating that their combination may be an effective therapy for t(8; 21) leukemia.

关键词： AML1–ETO     c-KIT     homoharringtonine     oridonin     t(8     21) AML     synergistic effect    

HTML PDF 收藏

On the location of the secondary instantaneous poles in two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

《机械工程前沿（英文）》 2014年 第9卷 第1期   页码 34-40 doi: 10.1007/s11465-014-0290-1

摘要：

As the instant centers in planar mechanisms, the instantaneous poles (or instant poles, in brief) can be used for kinematic analysis in spherical mechanisms. One of the mandatory steps in this analysis is the determination of the location of these poles. This paper presents a theorem showing analytically that the locus of an unknown secondary instant pole in two-degree-of-freedom (2-DOF) spherical mechanisms is a great circle (GC). The exact location of the pole on its GC is obtained based on the configuration of the mechanism and velocity ratio of the two inputs. Moreover, using the results of the theorem, a geometrical technique is presented to determine the GC of the pole.

关键词： spherical mechanisms     instantaneous poles     great circle     angular velocity    

HTML PDF 收藏

Stiffness of a 3-degree of freedom translational parallel kinematic machine

null

《机械工程前沿（英文）》 2014年 第9卷 第3期   页码 233-241 doi: 10.1007/s11465-014-0312-z

摘要：

In this paper, a typical 3-degree of freedom (3-DOF) translational parallel kinematic machine (PKM) is studied and analyzed whose tool platform has only translations along X-, Y- and Z-axes. It consists of three limbs, each of which have arm and forearm with prismatic-revolute-revolute-revolute (PRRR) joints. Inverse kinematics analysis is carried out to find the slider coordinates and joint angles for a given position of tool platform. Stiffness modeling is done based on the compliance matrices of arm and forearm of each limb. Using the stiffness modeling the variations of minimum and maximum translational stiffness in the workspace are analyzed. For various architectural parameters of the 3-DOF PKM the tendency of variations on the minimum and maximum stiffness over the entire workspace is studied; and also the deflections of the tool platform along X, Y, and Z directions with respect to various forces are presented.

关键词： 3-DOF translational PKM     inverse kinematics     stiffness modeling     translational stiffness    

HTML PDF 收藏

Water resource conservation promotes synergy between economy and environment in China’s northern drylands

《环境科学与工程前沿（英文）》 2022年 第16卷 第3期 doi: 10.1007/s11783-021-1462-y

摘要：

•Considering evenness provides a more accurate assessment of sustainable development.

关键词： Water conservation     Environmental protection     Industry transformation     Evenness     Sustainable development     Dryland    

HTML PDF 收藏

A survey of instantaneous poles for a class of two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

《机械工程前沿（英文）》 2014年 第9卷 第4期   页码 344-353 doi: 10.1007/s11465-014-0320-z

摘要：

This paper is a detailed exploration of instantaneous poles for a class of two-degree-of-freedom (two-DOF) spherical mechanisms (SMs) with seven links or bars. For two-DOF SMs, the secondary instantaneous poles (the ones which cannot be found by direct inspection) must lie on the specified great circles. For many of these mechanisms, however, some of these great circles cannot be obtained by a direct application of Aronhold-Kennedy theorem. This paper presents geometrical and analytical techniques to locate these unknown great circles for three topologies of seven-bar two-DOF SMs.

关键词： spherical mechanisms     instantaneous poles     Aronhold-Kennedy theorem     great circles     pencil of meridian    

HTML PDF 收藏

investigation and analysis of heat transfer enhancement in channel by longitudinal vortex based on field synergy

TAO Wenquan, WU Junmei

《能源前沿（英文）》 2008年 第2卷 第1期   页码 71-78 doi: 10.1007/s11708-008-0001-x

摘要： 3-D numerical simulations were presented for laminar flow and heat transfer characteristics in a rectangular channel with vortex generators. The effects of Reynolds number (from 800 to 3 000), the attack angle of vortex generator (from 15° to 90°) and the shape of vortex generator were examined. The numerical results were analyzed based on the field synergy principle. It is found that the inherent mechanism of the heat transfer enhancement by longitudinal vortex can be explained by the field synergy principle, that is, the second flow generated by vortex generators results in the reduction of the intersection angle between the velocity and fluid temperature gradient. The longitudinal vortex improves the field synergy of the large downstream region of longitudinal vortex generator (LVG) and the region near (LVG); however, transverse vortex only improves the synergy of the region near vortex generator. Thus, longitudinal vortex can enhance the integral heat transfer of the flow field, while transverse vortex can only enhance the local heat transfer. The synergy angle decreases with the increase of Reynolds number for the channel with LVG to differ from the result obtained from the plain channel, and the triangle winglet performs better than the rectanglar one under the same surface area condition.

关键词： inherent mechanism     integral     surface     rectanglar     longitudinal    

HTML PDF 收藏

Error analysis and optimization of a 3-degree of freedom translational Parallel Kinematic Machine

null

《机械工程前沿（英文）》 2014年 第9卷 第2期   页码 120-129 doi: 10.1007/s11465-014-0300-3

摘要：

In this paper, error modeling and analysis of a typical 3-degree of freedom translational Parallel Kinematic Machine is presented. This mechanism provides translational motion along the Cartesian X-, Y- and Z- axes. It consists of three limbs each having an arm and forearm with prismatic-revolute-revolute-revolute joints. The moving or tool platform maintains same orientation in the entire workspace due to its joint arrangement. From inverse kinematics, the joint angles for a given position of tool platform necessary for the error modeling and analysis are obtained. Error modeling is done based on the differentiation of the inverse kinematic equations. Variation of pose errors along X, Y and Z directions for a set of dimensions of the parallel kinematic machine is presented. A non-dimensional performance index, namely, global error transformation index is used to study the influence of dimensions and its corresponding global maximum pose error is reported. An attempt is made to find the optimal dimensions of the Parallel Kinematic Machine using Genetic Algorithms in MATLAB. The methodology presented and the results obtained are useful for predicting the performance capability of the Parallel Kinematic Machine under study.

关键词： translational Parallel Kinematic Machine     error modeling     global error transformation index    

HTML PDF 收藏

Regional seismic-damage prediction of buildings under mainshock–aftershock sequence

Xinzheng LU, Qingle CHENG, Zhen XU, Chen XIONG

《工程管理前沿（英文）》 2021年 第8卷 第1期   页码 122-134 doi: 10.1007/s42524-019-0072-x

摘要： Strong aftershocks generally occur following a significant earthquake. Aftershocks further damage buildings weakened by mainshocks. Thus, the accurate and efficient prediction of aftershock-induced damage to buildings on a regional scale is crucial for decision making for post-earthquake rescue and emergency response. A framework to predict regional seismic damage of buildings under a mainshock–aftershock (MS–AS) sequence is proposed in this study based on city-scale nonlinear time-history analysis (THA). Specifically, an MS–AS sequence-generation method is proposed to generate a potential MS–AS sequence that can account for the amplification, spectrum, duration, magnitude, and site condition of a target area. Moreover, city-scale nonlinear THA is adopted to predict building seismic damage subjected to MS–AS sequences. The accuracy and reliability of city-scale nonlinear THA for an MS–AS sequence are validated by as-recorded seismic responses of buildings and simulation results in published literature. The town of Longtoushan, which was damaged during the Ludian earthquake, is used as a case study to illustrate the detailed procedure and advantages of the proposed framework. The primary conclusions are as follows. (1) Regional seismic damage of buildings under an MS–AS sequence can be predicted reasonably and accurately by city-scale nonlinear THA. (2) An MS–AS sequence can be generated reasonably by the proposed MS–AS sequence-generation method. (3) Regional seismic damage of buildings under different MS–AS scenarios can be provided efficiently by the proposed framework, which in turn can provide a useful reference for earthquake emergency response and scientific decision making for earthquake disaster relief.

关键词： regional seismic damage prediction     city-scale nonlinear time-history analysis     mainshock–aftershock sequence     multiple degree-of-freedom (MDOF) model     2014 Ludian earthquake    

HTML PDF 收藏

煤炭高效洁净化利用的研究

陈吟颖,王淑娟,陈昌和,徐旭常

《中国工程科学》 2011年 第13卷 第6期   页码 51-56

摘要：

通过分析我国目前煤炭利用的主要方式和存在的问题，分析对比国内外煤炭高效洁净化利用技术，研究高效洁净化利用技术对环境的影响程度，建立了煤炭高效洁净化利用指标体系，给出了评价煤炭高效洁净化利用程度的洁净化度、生态优化度、低碳度的概念并作出了相应的定量判据，最后提出了我国2030年、2050年煤炭高效洁净化利用的有效途径和发展战略。

关键词： 洁净煤发电     洁净化度     能源可持续发展综合指标     生态优化度     低碳度    

HTML PDF 收藏

标题 作者 时间 类型 操作

Analysis of synergy degree and its influencing factors in hydropower EPC project management

Jiwei ZHU, Hua GAO, Jiangrui WANG

期刊论文

Effect of fiber hybridization on energy absorption and synergy in concrete

Ahmadreza RAMEZANI, Mohammad Reza ESFAHANI

期刊论文

Numerical analysis on heat transfer enhancement by longitudinal vortex based on field synergy principle

WU Junmei, TAO Wenquan

期刊论文

论正态云模型的普适性

李德毅,刘常昱

期刊论文

Enhanced synergy between Cu

Jingwei Zhang, Lingxin Kong, Yao Chen, Huijiang Huang, Huanhuan Zhang, Yaqi Yao, Yuxi Xu, Yan Xu, Shengping Wang, Xinbin Ma, Yujun Zhao

期刊论文

An Evaluation Model for the Coordinated Development of a Circular Economy in China and Its Application

Ji-liang Zheng,Chen Zheng,Pan Chen,Ching Yuan Luk

期刊论文

Homoharringtonine synergy with oridonin in treatment of t(8; 21) acute myeloid leukemia

Weina Zhang, Ying Lu, Tao Zhen, Xinjie Chen, Ming Zhang, Ping Liu, Xiangqin Weng, Bing Chen, Yueying Wang

期刊论文

On the location of the secondary instantaneous poles in two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

期刊论文

Stiffness of a 3-degree of freedom translational parallel kinematic machine

null

期刊论文

Water resource conservation promotes synergy between economy and environment in China’s northern drylands

期刊论文

A survey of instantaneous poles for a class of two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

期刊论文

investigation and analysis of heat transfer enhancement in channel by longitudinal vortex based on field synergy

TAO Wenquan, WU Junmei

期刊论文

Error analysis and optimization of a 3-degree of freedom translational Parallel Kinematic Machine

null

期刊论文

Regional seismic-damage prediction of buildings under mainshock–aftershock sequence

Xinzheng LU, Qingle CHENG, Zhen XU, Chen XIONG

期刊论文

煤炭高效洁净化利用的研究

陈吟颖,王淑娟,陈昌和,徐旭常

期刊论文