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New nonlinear stiffness actuator with predefined torque‒deflection profile

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0721-3

摘要： A nonlinear stiffness actuator (NSA) could achieve high torque/force resolution in low stiffness range and high bandwidth in high stiffness range, both of which are beneficial for physical interaction between a robot and the environment. Currently, most of NSAs are complex and hardly used for engineering. In this paper, oriented to engineering applications, a new simple NSA was proposed, mainly including leaf springs and especially designed cams, which could perform a predefined relationship between torque and deflection. The new NSA has a compact structure, and it is lightweight, both of which are also beneficial for its practical application. An analytical methodology that maps the predefined relationship between torque and deflection to the profile of the cam was developed. The optimal parameters of the structure were given by analyzing the weight of the NSA and the mechanic characteristic of the leaf spring. Though sliding friction force is inevitable because no rollers were used in the cam-based mechanism, the sliding displacement between the cam and the leaf spring is very small, and consumption of sliding friction force is very low. Simulations of different torque‒deflection profiles were carried out to verify the accuracy and applicability of performing predefined torque‒deflection profiles. Three kinds of prototype experiments, including verification experiment of the predefined torque‒deflection profile, torque tracking experiment, and position tracking experiment under different loads, were conducted. The results prove the accuracy of performing the predefined torque‒deflection profile, the tracking performance, and the interactive performance of the new NSA.

关键词： compliant actuator     nonlinear stiffness actuator     nonlinear spring     predefined torque−deflection profile    

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Pull-through capacity of bolted thin steel plate

Zhongwei ZHAO, Miao LIU, Haiqing LIU, Bing LIANG, Yongjing LI, Yuzhuo ZHANG

《结构与土木工程前沿（英文）》 2020年 第14卷 第5期   页码 1166-1179 doi: 10.1007/s11709-020-0641-4

摘要： The loading capacity in the axial direction of a bolted thin steel plate was investigated. A refined numerical model of bolt was first constructed and then validated using existing experiment results. Parametrical analysis was performed to reveal the influences of geometric parameters, including the effective depth of the cap nut, the yield strength of the steel plate, the preload of the bolt, and shear force, on the ultimate loading capacity. Then, an analytical method was proposed to predict the ultimate load of the bolted thin steel plate. Results derived using the numerical and analytical methods were compared and the results indicated that the analytical method can accurately predict the pull-through capacity of bolted thin steel plates. The work reported in this paper can provide a simplified calculation method for the loading capacity in the axial direction of a bolt.

关键词： bolted thin steel plate     refined numerical model     loading capacity     nonlinear spring element     analytical method    

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Iterative finite element model of nonlinear viscoplastic analyses for blended granular porous media

WU Yuching, ZHU Cimian

《结构与土木工程前沿（英文）》 2007年 第1卷 第4期   页码 464-473 doi: 10.1007/s11709-007-0063-6

摘要： The iterative finite element model, in which an element is used to represent a single particle, is generated to analyze the global behavior of multiple-material aggregates of materially nonlinear viscoplastic particles. The genera

关键词： nonlinear viscoplastic     iterative     behavior     multiple-material    

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Slope stability analysis based on a multigrid method using a nonlinear 3D finite element model

Yaoru LIU, Zhu HE, Bo LI, Qiang YANG

《结构与土木工程前沿（英文）》 2013年 第7卷 第1期   页码 24-31 doi: 10.1007/s11709-013-0190-1

摘要： The rigid-body limit equilibrium method cannot reflect the actual stress distribution in a rock mass, and the finite-element-based strength reduction method also has some problems with respect to convergence. To address these problems, a multi-grid method was adopted in this study to establish a structural grid for finite element computation and a slip surface grid for computing slope stability safety factors. This method can be used to determine the stability safety factor for any slip surface or slide block through a combination of nonlinear finite element analysis and limit equilibrium analysis. An ideal elastic–plastic incremental analysis method based on the Drucker–Prager yield criterion was adopted in the nonlinear finite element computation. Elasto-plastic computation achieves good convergence for both small load steps and large load steps and can increase computation precision to a certain extent. To increase the scale and accuracy of the computation, TFINE, a finite element parallel computation program, was used to analyze the influence of grid density on the accuracy of the computation results and was then applied to analysis of the stability of the Jinping high slope. A comparison of the results with results obtained using the rigid-body limit equilibrium method showed that the slope stability safety factors determined using finite element analysis were greater than those obtained using the rigid-body limit equilibrium method and were in better agreement with actual values because nonlinear stress adjustment was considered in the calculation.

关键词： slope     stability     multi-grid method     nonlinear     finite element method    

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Nonlinear finite element analysis of short-limbed wall

Zhi ZHANG, Qian GU, Shaomin PENG, Quanzhi CAI

《结构与土木工程前沿（英文）》 2009年 第3卷 第2期   页码 125-130 doi: 10.1007/s11709-009-0025-2

摘要： Combined with the actual project, this paper carries out a nonlinear finite element analysis on 2 groups, 6 short-limbed shear walls, through the finite element calculation software ANSYS. The stress-strain relation of the models, and the effects of the type of sections and the axial compression ratios on the models can be obtained, providing a reference for future design.

关键词： short-limbed wall (SLW)     nonlinear finite element     separate model     axial compression ratios    

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Study of an artificial boundary condition based on the damping-solvent extraction method

Qiang XU, Jianyun CHEN, Jing LI, Mingming WANG

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 281-287 doi: 10.1007/s11709-012-0167-5

摘要： A new artificial boundary condition for time domain analysis of a structure-unlimited-foundation system was proposed. The boundary condition was based on the damping-solvent extraction method. The principle of the damping-solvent extraction method was described. An artificial boundary condition was then established by setting two spring-damper systems and one artificial damping limited region. A test example was developed to verify that the proposed boundary condition and model had high precision. Compared with the damping-solvent extraction method, this boundary condition is easier to be applied to finite element method (FEM)-based numerical calculations.

关键词： damping-solvent extraction method     structure-unlimited-foundation system     spring-damper system     artificial damping limited region     finite element method    

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T形截面柱框架节点试验及非线性有限元分析

陈昌宏,黄莺,马乐为,吴敏哲,单建

《中国工程科学》 2007年 第9卷 第11期   页码 92-95

摘要：

对6个T形截面柱框架节点试件进行了试验，分别以梁截面高度、柱轴压比和节点区水平箍筋体积配箍率为变量参数，研究了节点区裂缝的形成与开展、节点的破坏机理；提出在低周期反复荷载作用下T形柱框架节点的裂缝呈反“K” 型，而不是类似于常规矩形节点的“X”型交叉裂缝，其受力机理偏于较陡的斜压杆受力模型；运用大型通用有限元软件ANSYS的二次开发语言APDL对T形截面柱节点进行非线性有限元分析，结果表明离散型非线性有限元模型计算结果与试验结果有很好的吻合。改变有限元程序参数使节点发生核心区剪压破坏，对节点裂缝的形成与开

关键词： T形节点     裂缝     破坏机理     ANSYS     非线性有限元    

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Analysis and characterization of wind-solar-constant torque spring hybridized model

Shantanu ACHARYA,Subhadeep BHATTACHARJEE

《能源前沿（英文）》 2014年 第8卷 第3期   页码 279-289 doi: 10.1007/s11708-014-0312-z

摘要： Solar and wind are the most promising renewable energy resources. But their unpredictable and varying nature prevents them from being used as the sole resource for power generation. This paper presents a model of wind and solar thermal hybrid power plant with a spring storage system which is expected to play an efficient role in combating with the drawbacks related to renewable power generation. In the proposed scheme, wind energy is harnessed by a hybrid vertical axis wind turbine, solar energy is utilized by a Stirling engine, and the surplus energy is stored in a winding spring. The paper discusses the working methodologies and analyses the performance of such 2.6 kW hybrid power plant model. It has been observed that the plant is capable of consistently generating 50% of its rated capacity irrespective of limitations in solar and wind resources.

关键词： hybrid vertical axis wind turbine     Stirling engine     solar-thermal energy     wind energy     constant torque spring    

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Back to the spring of Wuhan: facts and hope of COVID-19 outbreak

Guangbiao Zhou, Saijuan Chen, Zhu Chen

《医学前沿（英文）》 2020年 第14卷 第2期   页码 113-116 doi: 10.1007/s11684-020-0758-9

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Static balancing of planar articulated robots

Giuseppe QUAGLIA,Zhe YIN

《机械工程前沿（英文）》 2015年 第10卷 第4期   页码 326-343 doi: 10.1007/s11465-015-0355-9

摘要：

Static balancing for a manipulator’s weight is necessary in terms of energy saving and performance improvement. This paper proposes a method to design balancing devices for articulated robots in industry, based on robotic dynamics. Full design details for the balancing system using springs are presented from two aspects: One is the optimization for the position of the balancing system; the other is the design of the spring parameters. As examples, two feasible balancing devices are proposed, based on different robotic structures: The first solution consists of linkages and springs; the other consists of pulleys, cross mechanisms and (hydro-) pneumatic springs. Then the two solutions are compared. Pneumatic, hydro-pneumatic and mechanical springs are discussed and their parameters are decided according to the requirements of torque compensation. Numerical results show that with the proper design using the methodology presented in this paper, an articulated robot can be statically balanced perfectly in all configurations. This paper therefore provides a design method of the balancing system for other similar structures.

关键词： robotics     static balancing     pneumatic spring     mechanical spring     torque compensation    

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A perspective of “Nuclear Hot Spring” for long-term sustainable economy of the world

Yingzhong LU

《能源前沿（英文）》 2011年 第5卷 第4期   页码 349-357 doi: 10.1007/s11708-011-0168-4

摘要： The rapid growth of human economy in the late 20th century gave rise to great concern over sustainability of the world. A pessimistic “Full World Model” forecasts that human economy could not develop further. The nuclear fission (and fusion later), however, could release huge amount of energy to create sufficient useful material resources and turn the said pessimistic modelinto a new optimistic “Sustainable World Model”.The dilemma of nuclear energy (Military Giant vs. Civil Dwarf) jeopardizes its performance as a “Technologic Fixer”. According to Mother Nature’s teachings, the elimination of the root-causes of the design-based risk factors could solve this problem. Recent technology break-through from inherent safety to natural safety has been made in China. The proposed full-power natural circulation “Nuclear Hot Spring (NHS)” reactor could operate solely on natural forces without complex man-made coolant circulation equipment and human-operated control systems. The cheap, unlimited supply of energy from nuclear energy could change the geopolitics forever, and finally eliminate the root-causes of most international and regional conflicts.

关键词： natural safety reactor     full power natural circulation     sustainable world economy    

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Spectral reflectance indices as proxies for yield potential and heat stress tolerance in spring wheat

Caiyun LIU, Francisco PINTO, C. Mariano COSSANI, Sivakumar SUKUMARAN, Matthew P. REYNOLDS

《农业科学与工程前沿（英文）》 2019年 第6卷 第3期   页码 296-308 doi: 10.15302/J-FASE-2019269

摘要：

The application of spectral reflectance indices (SRIs) as proxies to screen for yield potential (YP) and heat stress (HS) is emerging in crop breeding programs. Thus, a comparison of SRIs and their associations with grain yield (GY) under YP and HS conditions is important. In this study, we assessed the usefulness of 27 SRIs for indirect selection for agronomic traits by evaluating an elite spring wheat association mapping initiative (WAMI) population comprising 287 elite lines under YP and HS conditions. Genetic and phenotypic analysis identified 11 and 9 SRIs in different developmental stages as efficient indirect selection indices for yield in YP and HS conditions, respectively. We identified enhanced vegetation index (EVI) as the common SRI associated with GY under YP at booting, heading and late heading stages, whereas photochemical reflectance index (PRI) and normalized difference vegetation index (NDVI) were the common SRIs under booting and heading stages in HS. Genome-wide association study (GWAS) using 18704 single nucleotide polymorphisms (SNPs) from Illumina iSelect 90K identified 280 and 43 marker-trait associations for efficient SRIs at different developmental stages under YP and HS, respectively. Common genomic regions for multiple SRIs were identified in 14 regions in 9 chromosomes: 1B (60–62 cM), 3A (15, 85–90, 101–105 cM), 3B (132–134 cM), 4A (47–51 cM), 4B (71–75 cM), 5A (43–49, 56–60, 89–93 cM), 5B (124–125 cM), 6A (80–85 cM), and 6B (57–59, 71 cM). Among them, SNPs in chromosome 5A (89–93 cM) and 6A (80–85 cM) were co-located for yield and yield related traits. Overall, this study highlights the utility of SRIs as proxies for GY under YP and HS. High heritability estimates and identification of marker-trait associations indicate that SRIs are useful tools for understanding the genetic basis of agronomic and physiological traits.

关键词： genome-wide association study (GWAS)     heat tolerance     spectral reflectance     spring wheat    

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Host protection against Omicron BA.2.2 sublineages by prior vaccination in spring 2022 COVID-19 outbreak

《医学前沿（英文）》 2023年 第17卷 第3期   页码 562-575 doi: 10.1007/s11684-022-0977-3

摘要： The Omicron family of SARS-CoV-2 variants are currently driving the COVID-19 pandemic. Here we analyzed the clinical laboratory test results of 9911 Omicron BA.2.2 sublineages-infected symptomatic patients without earlier infection histories during a SARS-CoV-2 outbreak in Shanghai in spring 2022. Compared to an earlier patient cohort infected by SARS-CoV-2 prototype strains in 2020, BA.2.2 infection led to distinct fluctuations of pathophysiological markers in the peripheral blood. In particular, severe/critical cases of COVID-19 post BA.2.2 infection were associated with less pro-inflammatory macrophage activation and stronger interferon alpha response in the bronchoalveolar microenvironment. Importantly, the abnormal biomarkers were significantly subdued in individuals who had been immunized by 2 or 3 doses of SARS-CoV-2 prototype-inactivated vaccines, supporting the estimation of an overall 96.02% of protection rate against severe/critical disease in the 4854 cases in our BA.2.2 patient cohort with traceable vaccination records. Furthermore, even though age was a critical risk factor of the severity of COVID-19 post BA.2.2 infection, vaccination-elicited protection against severe/critical COVID-19 reached 90.15% in patients aged ≥ 60 years old. Together, our study delineates the pathophysiological features of Omicron BA.2.2 sublineages and demonstrates significant protection conferred by prior prototype-based inactivated vaccines.

关键词： SARS-CoV-2     COVID-19     host response     bronchoalveolar lavage fluid (BALF)    

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铰接式自卸车橡胶弹簧悬架系统动力学仿真分析与实验研究

许志华,孙庆鸿,孙蓓蓓,马铸,李锁云,王华君

《中国工程科学》 2005年 第7卷 第9期   页码 34-39

摘要：

以AD250铰接式自卸车橡胶弹簧悬架系统为研究对象，运用虚拟样机技术，在不同载荷和车速下对其进行了动力学仿真分析，仿真结果与实验结果具有很好的一致性，表明所建模型是准确的；分析表明，前悬架橡胶弹簧刚度的非线性特性能满足前悬架在不同载荷下具有等支承频率，从而保持稳定的行使平顺性要求；而后悬架系统在轻载荷下较之重载荷时具有较高的支承频率。分析的结果为橡胶弹簧悬架系统进一步优化设计提供了理论支持。

关键词： 铰接式自卸车     悬架     橡胶弹簧     动力学     非线性    

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Comparative proteomic analysis of cold responsive proteins in two wheat cultivars with different tolerance to spring

Shujuan ZHANG,Guoqi SONG,Yulian LI,Jie GAO,Jiao WANG,Guiju CHEN,Haosheng LI,Genying LI,Zhendong ZHAO

《农业科学与工程前沿（英文）》 2014年 第1卷 第1期   页码 37-45 doi: 10.15302/J-FASE-2014008

摘要： Spring radiation frost (SRF) is a severe environmental stress which impairs wheat yield and productivity worldwide. To better understand the mechanism of wheat ( ) responding to SRF, a comparative proteomic analysis was performed to analyze the changes of the key proteins in two wheat cultivars Jimai22 and Luyuan301 with high and low tolerance to SRF respectively. A total of 43 differentially expressed proteins (DEPs) which mainly involved in carbohydrate metabolism, amino acid metabolism, resistance proteins and antioxidant enzymes, photosynthesis and cellular respiration proteins, cell-wall related proteins, protein translation/processing/degradation and signal transduction were isolated and identified by two-dimensional electrophoresis and MALDI-TOF-TOF MS. The results revealed that of the 21 DEPs in Jimai22 responding to the SRF, 13 DEPs were upregulated and 8 DEPs were downregulated, and that of the 22 DEPs in Luyuan301, 9 DEPs were upregulated and 13 DEPs were downregulated. These DEPs might be responsible for the stronger cold resistance of Jimai22 compared to Luyuan301. The expression pattern and function analysis of these DEPs were very significant to understanding the mechanism of the SRF responses in wheat.

关键词： common wheat     spring radiation frost     proteomic analysis     2-DE     MALDI-TOF-TOF MS    

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标题 作者 时间 类型 操作

New nonlinear stiffness actuator with predefined torque‒deflection profile

期刊论文

Pull-through capacity of bolted thin steel plate

Zhongwei ZHAO, Miao LIU, Haiqing LIU, Bing LIANG, Yongjing LI, Yuzhuo ZHANG

期刊论文

Iterative finite element model of nonlinear viscoplastic analyses for blended granular porous media

WU Yuching, ZHU Cimian

期刊论文

Slope stability analysis based on a multigrid method using a nonlinear 3D finite element model

Yaoru LIU, Zhu HE, Bo LI, Qiang YANG

期刊论文

Nonlinear finite element analysis of short-limbed wall

Zhi ZHANG, Qian GU, Shaomin PENG, Quanzhi CAI

期刊论文

Study of an artificial boundary condition based on the damping-solvent extraction method

Qiang XU, Jianyun CHEN, Jing LI, Mingming WANG

期刊论文

T形截面柱框架节点试验及非线性有限元分析

陈昌宏,黄莺,马乐为,吴敏哲,单建

期刊论文

Analysis and characterization of wind-solar-constant torque spring hybridized model

Shantanu ACHARYA,Subhadeep BHATTACHARJEE

期刊论文

Back to the spring of Wuhan: facts and hope of COVID-19 outbreak

Guangbiao Zhou, Saijuan Chen, Zhu Chen

期刊论文

Static balancing of planar articulated robots

Giuseppe QUAGLIA,Zhe YIN

期刊论文

A perspective of “Nuclear Hot Spring” for long-term sustainable economy of the world

Yingzhong LU

期刊论文

Spectral reflectance indices as proxies for yield potential and heat stress tolerance in spring wheat

Caiyun LIU, Francisco PINTO, C. Mariano COSSANI, Sivakumar SUKUMARAN, Matthew P. REYNOLDS

期刊论文

Host protection against Omicron BA.2.2 sublineages by prior vaccination in spring 2022 COVID-19 outbreak

期刊论文

铰接式自卸车橡胶弹簧悬架系统动力学仿真分析与实验研究

许志华,孙庆鸿,孙蓓蓓,马铸,李锁云,王华君

期刊论文

Comparative proteomic analysis of cold responsive proteins in two wheat cultivars with different tolerance to spring

Shujuan ZHANG,Guoqi SONG,Yulian LI,Jie GAO,Jiao WANG,Guiju CHEN,Haosheng LI,Genying LI,Zhendong ZHAO

期刊论文