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Output tracking control of mobile manipulators based on dynamical sliding-mode control

WUYuxiang, FENG Ying, HU Yueming

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 110-115 doi: 10.1007/s11465-007-0019-5

摘要： A dynamical sliding-mode controller is devised to track the output of mobile manipulators. During the investigation, firstly a reduced dynamic model considering the dynamics of the driving motor is developed for mobile manipulators. Then, the system is decomposed into four lower-dimensional subsystems by means of diffeomorphism and nonlinear input transformation. Moreover, a design method of the dynamical sliding-mode controller that is applied to the output tracking of mobile manipulators is proposed. The simulation results indicate that the dynamical sliding-mode controller can not only track the given trajectory correctly but also reduce the chattering of sliding-mode control system considerably.

关键词： lower-dimensional     nonlinear     trajectory     tracking     diffeomorphism    

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Simulation of flow excursion and thermal siphon under natural circulation condition with lower pressureand lower quality

WANG Jianjun, YANG Xingtuan, JIANG Shengyao

《能源前沿（英文）》 2008年 第2卷 第2期   页码 169-173 doi: 10.1007/s11708-008-0044-z

摘要： The simulation of flow excursion was conducted under HRTL-5 condition. The mechanism analysis and the simulation of thermal siphon process were also performed. The result shows that the computer code can be used to simulate the static instability of a natural circulation system and the simulation of flow excursion almost conforms to the experiment result.

关键词： HRTL-5     experiment     circulation     simulation     thermal    

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Dynamic fate modeling of γ-hexachlorocyclohexane in the lower reaches of the Liao River

LIU Zhenyu, YANG Fenglin, QUAN Xie, ZHANG Xiaohong

《环境科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 166-171 doi: 10.1007/s11783-007-0029-x

摘要： A QWASI model dependent on temperature is parameterized to describe the long-term fate of persistent organic pollutants (POPs) in the Liao River. The model parameters, namely fugacity capacity, degradation rate, and transfer coefficient, are profoundly affected by temperature. This model is used to simulate the fate of γ-hexachlorocyclohexane (γ-HCH) in the lower reaches of the Liao River from 1998 to 2008. Modeling results show that γ-HCH fugacity capacities in air, water, and sediment increase as temperature decreases, and the transfer and transformation rate coefficients increase as temperature increases. The variations of transfer and transformation parameter values depend on fugacity capacities, and transfer and transformation coefficients simultaneously. The performance of the model is evaluated by comparing the predicted and observed concentrations in the water and sediment of the Liao River. The predicted values agree well with the observed value in the order of magnitude, in most cases within the factor of 3. It is believed that the model is appropriate for simulating the long term fate of POPs in the Liao River.

关键词： coefficient     POPs     temperature     sediment increase     dependent    

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Does financial development lower energy intensity?

Philip Kofi ADOM, Michael Owusu APPIAH, Mawunyo Prosper AGRADI

《能源前沿（英文）》 2020年 第14卷 第3期   页码 620-634 doi: 10.1007/s11708-019-0619-x

摘要： The growth-induced effects of financial development have been well-established in the empirical literature, as well as the significance of financial development to energy demand behavior. However, the empirical evidence on the relationship between financial development and energy intensity remains sparse in the literature. Given the multifaceted nature of the effects of financial development, the proposed relationship seems a complex one and warrants an empirical investigation. Using the case of Ghana, this study provides an empirical answer to the question: does financial development lower energy intensity? To provide solid grounds for either rejection or acceptance of the null hypothesis, this study performed several robustness checks. Generally, the evidence revealed that financial development lowers energy intensity. Further, the results revealed that the price of energy, trade liberalization and industry structure play significant roles. These results have important implications for the design of macro energy efficiency policies and the creation of a ‘Green Bank’.

关键词： financial development     energy intensity     energy efficiency     Ghana    

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Correction to: Effect of undercut on the lower bound stability of vertical rock escarpment using finite

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0035-5

摘要： Correction to: Effect of undercut on the lower bound stability of vertical rock escarpment using finite element and power cone programming

关键词： finite element power     stability rock escarpment    

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Natural ecological water demand in the lower Heihe River

FU Xinfeng, HE Hongmou, JIANG Xiaohui, WANG Guoqing, YANG Shengtian

《环境科学与工程前沿（英文）》 2008年 第2卷 第1期   页码 63-68 doi: 10.1007/s11783-008-0022-z

摘要： The ecological environment in the lower Heihe River has been deteriorating due to large water consumption in the upper and middle reaches, and less available water downstream. To restore the ecological environment in the lower Heihe River, the ecological water demand should be guaranteed. The natural vegetation area in the lower Heihe River was first obtained through the interpretation of remote sensing images taken in 1998. Based on the analysis for the Quota of the natural ecological water demand in the lower Heihe River and the determination of the natural ecological water demand calculation method, the ecological water demand in the lower Heihe River was calculated. Finally, the natural ecological water demand in the lower Heihe River under the current situation was calculated with the groundwater storage volume change method, Aweliyongrufe method and the measured water volume method. In comparison, the natural ecological water demand in the lower Heihe River is 3.91–4.05 × 10 m.
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潜在用于单侧膝受伤患者的传感引导步态同步下肢外骨骼 Research Articles

王东海1,2

《信息与电子工程前沿（英文）》 2022年 第23卷 第6期   页码 920-936 doi: 10.1631/FITEE.2000465

摘要：

本文展示了一种可潜在帮助单侧膝受伤患者正常行走的传感引导步态同步下肢外骨骼系统。外骨骼能够减轻人体体重对受伤膝下肢的负载，并维持与健康侧下肢行走步态摆动相同步。传感引导步态同步系统集成了人体传感网络，它能感知健康侧下肢的运动步态。基于测量的关节角度轨迹引导，安装电机的髋关节在行走中提起腿杆，并将膝受伤步态和健康步态以半周期延时进行同步。实验验证了下肢外骨骼的效果。本文比较了健康腿和膝受伤腿的测量关节角度轨迹、仿真的膝受力、人机交互力等方面，结果说明髋关节安装电机受控制的下肢外骨骼能够将受伤腿和体重支撑外骨骼的融合步态与健康腿步态进行同步。

关键词： 传感引导；下肢外骨骼；人体传感网络；步态同步；体重支撑    

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Bearing and uplift capacities of under-reamed piles in soft clay underlaid by stiff clay using lower-bound

Mantu MAJUMDER, Debarghya CHAKRABORTY

《结构与土木工程前沿（英文）》 2021年 第15卷 第2期   页码 537-551 doi: 10.1007/s11709-021-0708-x

摘要： Ensuring a safe foundation design in soft clay is always a challenging task to engineers. In the present study, the effectiveness of under-reamed piles in soft clay underlaid by stiff clay is numerically studied using the lower-bound finite element limit analysis (LB FELA). The bearing and uplift capacities of under-reamed piles are estimated through non-dimensional factors and , respectively. These factors increased remarkably and marginally compared to and of the piles without bulbs when the bulb is placed in stiff and soft clay, respectively. For a given ratio of undrained cohesion of stiff to soft clay ( / ), the factors and moderately increased with the increase in the length-to-shaft-diameter ratio ( / ) and adhesion factors in soft clay ( ) and stiff clay ( ). The variation of radial stress along the pile–soil interface, distribution of axial force in the under-reamed piles, and state of plastic shear failure in the soil are also studied under axial compression and tension. The results of this study are expected to be useful for the estimation of the bearing and uplift capacities of under-reamed piles in uniform clay and soft clay underlaid by stiff clay.

关键词： bearing capacity     uplift capacity     under-reamed pile     clay     limit analysis    

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Effect of undercut on the lower bound stability of vertical rock escarpment using finite element and

Shuvankar DAS; Debarghya CHAKRABORTY

《结构与土木工程前沿（英文）》 2022年 第16卷 第8期   页码 1040-1055 doi: 10.1007/s11709-022-0841-1

摘要： In the present study, the stability of a vertical rock escarpment is determined by considering the influence of undercut. Lower bound finite element limit analysis in association with Power Cone Programming (PCP) is applied to incorporate the failure of rock mass with the help of the Generalized Hoek-Brown yield criterion. The change in stability due to the presence of undercut is expressed in terms of a non-dimensional stability number (σci/γH). The variations of the magnitude of σci/γH are presented as design charts by considering the different magnitudes of undercut offset (H/vu and wu/vu) from the vertical edge and different magnitudes of Hoek-Brown rock mass strength parameters (Geological Strength Index (GSI), rock parameter (mi,), Disturbance factor (D)). The obtained results indicate that undercut can cause a severe stability problem in rock mass having poor strength. With the help of regression analysis of the computed results, a simplified design equation is proposed for obtaining σci/γH. By performing sensitivity analysis for an undisturbed vertical rock escarpment, we have found that the undercut height ratio (H/vu) is the most sensitive parameter followed by GSI, undercut shape ratio (wu/vu), and mi. The developed design equation as well as design charts can be useful for practicing engineers to determine the stability of the vertical rock escarpment in the presence of undercut. Failure patterns are also presented to understand type of failure and extent of plastic state during collapse.

关键词： undercut     vertical escarpment     stability     Hoek-Brown yield criterion     PCP    

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引海水冲刷河口治理黄河下游

林秉南,周建军,张仁

《中国工程科学》 2000年 第2卷 第4期   页码 25-33

摘要：

提出引海水5000～1 500m3/s在利津注入黄河冲刷河口。冲刷后，在利津将产生3.3～7.9m的水面跌差，可制止黄河河口延伸的溯源淤积作用上延，并诱发其上游产生溯源冲刷。估计可使艾山以下河道得到冲深。因挟沙海水的密度大于渤海环境水体的密度，咸浑水进入渤海时可形成异重流，将泥沙输去远方；而且断流期间河口还可能蚀退；因此引海水流量足够时，可使河口不外延或外延缓慢。从长远看，河口侵蚀基准面得到降低后，可以使黄河下游的淤积面均得到降低。这对缓解黄河下游河道持续淤高的局面和减少河口改道的风险都是有利的。

黄河下游额定冲沙水占黄河水资源总量很大比例，大量抽取淡水会增加下游的淤积。引海水冲刷河口，可 以增加河口地区从黄河抽取淡水的数量。这样抽取的淡水是冲沙水的一部分，不受用水分配额度的限制，对河 口地区的发展具有重要意义。引海水冲刷口门段，可向渤海注入大量咸浑水、有利于改进渤海的环境生态条件。 当然，引海水冲刷时须解决河道和引海水渠道的咸水外渗问题。

关键词： 引海水冲刷     黄河下游     悬河     水资源利用    

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High cadmium pollution risk on vegetable amaranth and a selection for pollution-safe cultivars to lower

Yihui ZHOU, Meng XUE, Zhongyi YANG, Yulian GONG, Jiangang YUAN, Chunyan ZHOU, Baifei HUANG

《环境科学与工程前沿（英文）》 2013年 第7卷 第2期   页码 219-230 doi: 10.1007/s11783-012-0469-9

摘要： A pot experiment was carried out by growing 29 different genotypes ( spp.) of vegetable amaranth under low- (0.12 mg·kg ) and middle- (0.40 mg·kg ) cadmium (Cd) exposure. The result showed that amaranth was vulnerable to cadmium (Cd) contamination in soil. Variations of Cd concentrations in both roots and edible parts among genotypes were significant ( <0.001) in both treatments. Cd concentrations in edible parts of the tested genotypes grown under low- and middle-Cd levels were significantly correlated ( <0.01), implying that Cd-accumulating property of amaranth is genotype-dependent. Differences in Cd chemical forms between cv. Nanxingdayemashixian (cv. Nan), a selected typical pollution-safe cultivar (Cd-PSC), and cv. Pennongjianyexian (cv. Pen), a selected typical non-Cd-PSC, under different Cd exposure conditions were compared. It was found that the alternation of Cd in F (Cd form extracted by 1 mol·L NaCl) may be a key factor in regulating Cd accumulation of different amaranth genotypes and that the protein-binding Cd is considered to be associated with Cd translocation. The results indicated that amaranth is capable of enduring high level of Cd pollution when grown as vegetable crop, and accordingly, consuming vegetable amaranth would bring high health risk. Therefore, adopting Cd-PSC strategy would help reducing the risk of Cd pollution in amaranth. In this study, cv. Nan was identified as a Cd-PSC and recommended to be applied production practice.

关键词： Amaranth     Cadmium (Cd)     Cd accumulation     pollution-safe cultivar (PSC)     Cd chemical forms     health risk    

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Three-dimensional stability analysis of the dam foundation at Baise

XU Qianjun, LI Xu, CHEN Zuyu

《结构与土木工程前沿（英文）》 2007年 第1卷 第2期   页码 217-221 doi: 10.1007/s11709-007-0026-y

摘要： It is usually difficult to determine the actual safety factors of rock masses in an ordinary two-dimensional stability analysis if the safety factors of the different cross sections in the rock mass vary significantly. In addition to the actual slope, arch dam abutment, and the actual foundation of a high building, another example is that the different cross sections of the foundation in the monolith of a gravity dam vary significantly, just like the condition at the overflow dam in the Baise project. A three-dimensional stability analysis method based on the upper-bound theorem was employed to solve this problem. The parameters used in the analysis were obtained from geomechanics tests, as well as continuity simulations of the randomly distributed joints. Two failure patterns against sliding are analyzed. One pattern is the foundation slide along deep-seated planes which were determined by calculations. The other pattern is the foundation slide along the planes across the bottom of the high steps in the foundation pit. The results indicate that a special overflow dam monolith can be considered to be safe in case of considering the three dimensional effect. However, a key wall with a depth of 5m must be constructed at the upper side of this monolith in order to ensure the safety of the foundation.

关键词： ordinary two-dimensional     randomly     monolith     three-dimensional stability     different    

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Review of human–robot coordination control for rehabilitation based on motor function evaluation

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0684-4

摘要： As a wearable and intelligent system, a lower limb exoskeleton rehabilitation robot can provide auxiliary rehabilitation training for patients with lower limb walking impairment/loss and address the existing problem of insufficient medical resources. One of the main elements of such a human–robot coupling system is a control system to ensure human–robot coordination. This review aims to summarise the development of human–robot coordination control and the associated research achievements and provide insight into the research challenges in promoting innovative design in such control systems. The patients’ functional disorders and clinical rehabilitation needs regarding lower limbs are analysed in detail, forming the basis for the human–robot coordination of lower limb rehabilitation robots. Then, human–robot coordination is discussed in terms of three aspects: modelling, perception and control. Based on the reviewed research, the demand for robotic rehabilitation, modelling for human–robot coupling systems with new structures and assessment methods with different etiologies based on multi-mode sensors are discussed in detail, suggesting development directions of human–robot coordination and providing a reference for relevant research.

关键词： human–robot coupling     lower limb rehabilitation     exoskeleton robot     motor assessment     dynamical model     perception    

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一种新型自主下肢外骨骼助行机器人的研制 Special Feature on Intelligent Robats

Yong HE, Nan LI, Chao WANG, Lin-qing XIA, Xu YONG, Xin-yu WU

《信息与电子工程前沿（英文）》 2019年 第20卷 第3期   页码 318-329 doi: 10.1631/FITEE.1800561

摘要： 目前，外骨骼被广泛应用于下肢运动障碍患者的步行辅助。现有外骨骼机器人大部分采用欠驱动模式，导致一系列使用问题，如行走过程中步行干扰和不自然步态。提出一种新型智能自主下肢外骨骼(Auto-LEE)，旨在改善穿戴式助行器用户体验，扩大应用范围。与传统外骨骼不同，Auto-LEE有10个自由度，所有关节都由直流电机独立驱动，使机器人能在无外部支撑下保持平衡行走。此外，在设计中采用模块化结构理念，在控制系统中考虑多模态人机交互。为验证机器人自主平衡双足行走能力，对比3种常用步态规划算法，初步实现行走实验。

关键词： 下肢；外骨骼；自平衡；双足行走；模块化设计    

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A hybrid deep learning model for robust prediction of the dimensional accuracy in precision milling of

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0688-0

摘要： The use of artificial intelligence to process sensor data and predict the dimensional accuracy of machined parts is of great interest to the manufacturing community and can facilitate the intelligent production of many key engineering components. In this study, we develop a predictive model of the dimensional accuracy for precision milling of thin-walled structural components. The aim is to classify three typical features of a structural component—squares, slots, and holes—into various categories based on their dimensional errors (i.e., “high precision,” “pass,” and “unqualified”). Two different types of classification schemes have been considered in this study: those that perform feature extraction by using the convolutional neural networks and those based on an explicit feature extraction procedure. The classification accuracy of the popular machine learning methods has been evaluated in comparison with the proposed deep learning model. Based on the experimental data collected during the milling experiments, the proposed model proved to be capable of predicting dimensional accuracy using cutting parameters (i.e., “static features”) and cutting-force data (i.e., “dynamic features”). The average classification accuracy obtained using the proposed deep learning model was 9.55% higher than the best machine learning algorithm considered in this paper. Moreover, the robustness of the hybrid model has been studied by considering the white Gaussian and coherent noises. Hence, the proposed hybrid model provides an efficient way of fusing different sources of process data and can be adopted for prediction of the machining quality in noisy environments.

关键词： precision milling     dimensional accuracy     cutting force     convolutional neural networks     coherent noise    

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标题 作者 时间 类型 操作

Output tracking control of mobile manipulators based on dynamical sliding-mode control

WUYuxiang, FENG Ying, HU Yueming

期刊论文

Simulation of flow excursion and thermal siphon under natural circulation condition with lower pressureand lower quality

WANG Jianjun, YANG Xingtuan, JIANG Shengyao

期刊论文

Dynamic fate modeling of γ-hexachlorocyclohexane in the lower reaches of the Liao River

LIU Zhenyu, YANG Fenglin, QUAN Xie, ZHANG Xiaohong

期刊论文

Does financial development lower energy intensity?

Philip Kofi ADOM, Michael Owusu APPIAH, Mawunyo Prosper AGRADI

期刊论文

Correction to: Effect of undercut on the lower bound stability of vertical rock escarpment using finite

期刊论文

Natural ecological water demand in the lower Heihe River

FU Xinfeng, HE Hongmou, JIANG Xiaohui, WANG Guoqing, YANG Shengtian

期刊论文

潜在用于单侧膝受伤患者的传感引导步态同步下肢外骨骼

王东海1,2

期刊论文

Bearing and uplift capacities of under-reamed piles in soft clay underlaid by stiff clay using lower-bound

Mantu MAJUMDER, Debarghya CHAKRABORTY

期刊论文

Effect of undercut on the lower bound stability of vertical rock escarpment using finite element and

Shuvankar DAS; Debarghya CHAKRABORTY

期刊论文

引海水冲刷河口治理黄河下游

林秉南,周建军,张仁

期刊论文

High cadmium pollution risk on vegetable amaranth and a selection for pollution-safe cultivars to lower

Yihui ZHOU, Meng XUE, Zhongyi YANG, Yulian GONG, Jiangang YUAN, Chunyan ZHOU, Baifei HUANG

期刊论文

Three-dimensional stability analysis of the dam foundation at Baise

XU Qianjun, LI Xu, CHEN Zuyu

期刊论文

Review of human–robot coordination control for rehabilitation based on motor function evaluation

期刊论文

一种新型自主下肢外骨骼助行机器人的研制

Yong HE, Nan LI, Chao WANG, Lin-qing XIA, Xu YONG, Xin-yu WU

期刊论文

A hybrid deep learning model for robust prediction of the dimensional accuracy in precision milling of

期刊论文