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Elastic analysis of heterogeneous thick-walled spherical pressure vessels with parabolic varying properties

Keyhan KARAMI, Majid ABEDI, Mohammad ZAMANI NEJAD, Mohammad Hassan LOTFIAN

《机械工程前沿（英文）》 2012年 第7卷 第4期   页码 433-438 doi: 10.1007/s11465-012-0336-1

摘要：

On the basis of plane elasticity theory (PET), the displacement and stress components in a thick-walled spherical pressure vessels made of heterogeneous materials subjected to internal and external pressure is developed. The mechanical properties except the Poisson’s ratio are assumed to obey the parabolic variations throughout the thickness. Effect of material inhomogeneity on the elastic deformations and stresses is investigated. The analytical solutions and the solutions carried out through the FEM have a good agreement. The values used in this study are arbitrary chosen to demonstrate the effect of inhomogeneity on displacements, and stresses distributions.

关键词： thick-walled spherical vessels     heterogeneous materials     FGM     FEM     parabolic varying properties    

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Demonstration project of safe and efficient mining operations in extra-thick coal seam

Jinhui WANG

《工程管理前沿（英文）》 2017年 第4卷 第1期   页码 110-110 doi: 10.15302/J-FEM-2016063

摘要：
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Fixturing technology and system for thin-walled parts machining: a review

《机械工程前沿（英文）》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0711-5

摘要： During the overall processing of thin-walled parts (TWPs), the guaranteed capability of the machining process and quality is determined by fixtures. Therefore, reliable fixtures suitable for the structure and machining process of TWP are essential. In this review, the key role of fixtures in the manufacturing system is initially discussed. The main problems in machining and workholding due to the characteristics of TWP are then analyzed in detail. Afterward, the definition of TWP fixtures is reinterpreted from narrow and broad perspectives. Fixture functions corresponding to the issues of machining and workholding are then clearly stated. Fixture categories are classified systematically according to previous research achievements, and the operation mode, functional characteristics, and structure of each fixture are comprehensively described. The function and execution mode of TWP fixtures are then systematically summarized and analyzed, and the functions of various TWP fixtures are evaluated. Some directions for future research on TWP fixtures technology are also proposed. The main purpose of this review is to provide some reference and guidance for scholars to examine TWP fixtures.

关键词： thin-walled part (TWP)     fixture     machining     fixture categories     fixture function    

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Dynamical research on spherical micro actuator with piezoelectric ceramic stacks drivers

ZHANG Ruihua, CHEN Haichu

《机械工程前沿（英文）》 2007年 第2卷 第4期   页码 433-438 doi: 10.1007/s11465-007-0074-y

摘要： This paper develops a 30 mm × 30 mm × 50 mm spherical micro actuator driven by piezoelectric ceramic stacks (PZT), and analyzes its dynamic performances. First, the space coordinate relationship of the spherical micro actuator and a dynamic model are set up. Second, The Runge-Kutta arithmetic is used to calculate the dynamical parameters of the micro actuator; the SIMULINK module of MATLAB is used to build the dynamical simulating model and then simulate it. Third, an experimental sample of the spherical micro actuator is developed, a micromanipulator is integrated with a micro-gripper based on the sample spherical micro actuator, and the experimental research on the micro assembly is conducted between a micro shaft of 180 μm and a micro spindle sleeve of 200 μm. Finally, the characteristics of the spherical micro actuator influenced by the mass of the metal sphere of the micro actuator, driving signal frequency, friction coefficient of the contact surface between the metal sphere and the friction block of the micro driving unit are analyzed. The experimental results indicate that the rotation resolution of the micro actuator reaches 0.000 1°, the rotation positioning precision reaches 0.000 5°, and the maximum working frequency is about 1200 Hz. The experimental results validate the back rotation vibration model of the spherical micro actuator. The micromanipulator integrated by the spherical micro actuator can meet the requirements of precise micro operation and assembly for micro electro mechanical systems (MEMS) or other microelements in micro degree fields.

关键词： spherical     micro-gripper     friction coefficient     dynamic     frequency    

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Analysis on damage causes of built-in corridor in core rock-fill dam on thick overburden: A case study

Jia’ao YU; Zhenzhong SHEN; Zhangxin HUANG

《结构与土木工程前沿（英文）》 2022年 第16卷 第6期   页码 762-780 doi: 10.1007/s11709-022-0847-8

摘要： The stress state of the built-in corridor in core rock-fill dam on thick overburden is extremely complex, which may produce cracking and damage. The purpose of this paper was to investigate the effect of thick overburden on the stress and deformation of the built-in corridor in a rock-fill dam, and ascertain the damage causes of the corridor. The rationality of the analysis method for corridor with similar structure is another focus. The approach is based on finite-element method and the calculation result accuracy is verified by the field monitoring data. The improved analysis method for corridors with similar structure is proposed by comparing various corridor load calculation methods and concrete constitutive models. Results demonstrate that the damage causes of the corridor are the deformability difference between the overburden and concrete and the special structural form. And the calculation model considering dam construction process, contact between concrete and surrounding soil, and concrete damage plasticity can reasonably reflect the mechanical behavior of the corridor. The research conclusions may have a reference significance for the analysis of tunnels similar to built-in corridors.

关键词： thick overburden     built-in corridor     stress     deformation     causes for damage     concrete damaged plasticity    

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Position-varying surface roughness prediction method considering compensated acceleration in milling of thin-walled

《机械工程前沿（英文）》 2021年 第16卷 第4期   页码 855-867 doi: 10.1007/s11465-021-0649-z

摘要： Machined surface roughness will affect parts’ service performance. Thus, predicting it in the machining is important to avoid rejects. Surface roughness will be affected by system position dependent vibration even under constant parameter with certain toolpath processing in the finishing. Aiming at surface roughness prediction in the machining process, this paper proposes a position-varying surface roughness prediction method based on compensated acceleration by using regression analysis. To reduce the stochastic error of measuring the machined surface profile height, the surface area is repeatedly measured three times, and Pauta criterion is adopted to eliminate abnormal points. The actual vibration state at any processing position is obtained through the single-point monitoring acceleration compensation model. Seven acceleration features are extracted, and valley, which has the highest R-square proving the effectiveness of the filtering features, is selected as the input of the prediction model by mutual information coefficients. Finally, by comparing the measured and predicted surface roughness curves, they have the same trends, with the average error of 16.28% and the minimum error of 0.16%. Moreover, the prediction curve matches and agrees well with the actual surface state, which verifies the accuracy and reliability of the model.

关键词： surface roughness prediction     compensated acceleration     milling     thin-walled workpiece    

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Endostatin specifically targets both tumor blood vessels and lymphatic vessels

Wei Zhuo, Yang Chen, Xiaomin Song, Yongzhang Luo

《医学前沿（英文）》 2011年 第5卷 第4期   页码 336-340 doi: 10.1007/s11684-011-0163-5

摘要： Endostatin, a 20 kDa C-terminal fragment of collagen XVIII, was first identified as a potent angiogenic inhibitor. The anti-angiogenic function of endostatin has been well documented during the past decade. Recently, several studies demonstrated that endostatin also inhibits tumor lymphangiogenesis and lymphatic metastasis. However, the exact mechanism that endostatin executes its anti-angiogenic and anti-lymphangiogenic functions remains elusive. In the current mini-review, we briefly summarize recent novel findings, including the functions of endostatin targeting not only angiogenesis but also lymphangiogenesis, and the underlying mechanism by which endostatin internalization regulates its biological functions.

关键词： endostatin     angiogenesis     lymphangiogenesis     nystatin     internalization     tumor    

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An analytical method for calculating torsional constants for arbitrary complicated thin-walled cross-sections

DU Baisong, GE Yaojun, ZHOU Zheng

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 293-297 doi: 10.1007/s11709-007-0038-7

摘要： In this paper, an analytical method is proposed for calculating torsional constants for complicated thin-walled cross-sections with arbitrary closed or open rib stiffeners. This method uses the free torsional theory and the principle of virtual work to build governing equilibrium equations involving unknown shear flows and twisting rate. After changing the form of the equations and combining these two unknowns into one, torsional function, which is a function of shear flow, shear modulus, and twisting rate, is included in the governing equations as only one of the unknowns. All the torsional functions can be easily obtained from these homogeneous linear equations, and torsional constants can be easily obtained from the torsional functions. The advantage of this method is that we can easily and directly obtain torsional constants from the torsional functions, rather than the more sophisticated shear flow and twisting rate calculations. Finally, a complicated thin-walled cross-section is given as a valid numerical example to verify the analytical method, which is much more accurate and simpler than the traditional finite element method.

关键词： homogeneous     complicated thin-walled     numerical example     advantage     torsional function    

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Adsorption of toluene, ethylbenzene and xylene isomers on multi-walled carbon nanotubes oxidized by different

Fei YU, Jie MA, Yanqing WU

《环境科学与工程前沿（英文）》 2012年 第6卷 第3期   页码 320-329 doi: 10.1007/s11783-011-0340-4

摘要： Multi-walled carbon nanotubes (MWCNTs) were fabricated and oxidized by different concentrations of sodium hypochlorite (NaOCl) solutions. The untreated MWCNTs and modified MWCNTs were employed as adsorbents to study their characterizations and adsorption performance of toluene, ethylbenzene and xylene isomers (TEX) in an aqueous solution. The physicochemical properties of MWCNTs were greatly affected after oxidation, which influences TEX adsorption capacity. The 3% NaOCl-oxidized MWCNTs shows the greatest enhancement in TEX adsorption, followed by the 30% NaOCl. More interestingly, the 15% NaOCl-oxidized MWCNTs has lower adsorption capacities than untreated MWCNTs. The adsorption mechanism of TEX on treated MWCNTs is attributed to the combined action of hydrophobic interaction, π-π bonding interaction between the aromatic ring of TEX and the oxygen-containing functional groups of MWCNTs and electrostatic interaction. 3% NaOCl solution could not only introduce much oxygen-containing functional groups on MWCNTs, but also lead to less damage for the pore structure. This suggests that the CNTs-3% NaOCl is efficient adsorbent for TEX and that they may possess good potential for TEX removal in wastewater treatment.

关键词： adsorption     toluene     ethylbenzene and xylene isomers (TEX)     multi-walled carbon nanotube     surface oxidation    

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Improvement in growth yield of single-walled carbon nanotubes with narrow chirality distribution by pulse

Bin Xu, Toshiro Kaneko, Toshiaki Kato

《化学科学与工程前沿（英文）》 2019年 第13卷 第3期   页码 485-492 doi: 10.1007/s11705-019-1831-2

摘要： A pulse plasma chemical vapor deposition (CVD) technique was developed for improving the growth yield of single-walled carbon nanotubes (SWNTs) with a narrow chirality distribution. The growth yield of the SWNTs could be improved by repetitive short duration pulse plasma CVD, while maintaining the initial narrow chirality distribution. Detailed growth dynamics is discussed based on a systematic investigation by changing the pulse parameters. The growth of SWNTs with a narrow chirality distribution could be controlled by the difference in the nucleation time required using catalysts comprising relatively small or large particles as the key factor. The nucleation can be controlled by adjusting the pulse on/off time ratio and the total processing time.

关键词： single-walled carbon nanotubes     chirality-controlled synthesis     pulse plasma chemical vapor deposition    

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Vibration analysis of multi-walled carbon nanotubes embedded in elastic medium

Pattabhi R. BUDARAPU,Sudhir Sastry YB,Brahmanandam JAVVAJI,D. Roy MAHAPATRA

《结构与土木工程前沿（英文）》 2014年 第8卷 第2期   页码 151-159 doi: 10.1007/s11709-014-0247-9

摘要： We propose a method to estimate the natural frequencies of the multi-walled carbon nanotubes (MWCNTs) embedded in an elastic medium. Each of the nested tubes is treated as an individual bar interacting with the adjacent nanotubes through the inter-tube Van der Waals forces. The effect of the elastic medium is introduced through an elastic model. The mathematical model is finally reduced to an eigen value problem and the eigen value problem is solved to arrive at the inter-tube resonances of the MWCNTs. Variation of the natural frequencies with different parameters are studied. The estimated results from the present method are compared with the literature and results are observed to be in close agreement.

关键词： natural frequencies     multi-walled carbon nanotubes (MWCNTS)     elastic medium    

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Unified solution of limit loads of thick wall cylinder subject to external pressure considering strain

CHEN Changfu, XIAO Shujun, YANG Yu

《结构与土木工程前沿（英文）》 2007年 第1卷 第3期   页码 329-333 doi: 10.1007/s11709-007-0043-x

摘要： Based on the unified strength theory [1], a unified strength criterion for strain softening materials, such as concrete or rock, was derived, and the elastic and plastic limit loads of a thick-walled cylinder made of these materials subject to external pressure were also given. In addition, the influence of some factors on the limit loads of such cylinders as the ratio of the external radius to internal radius,/, the coefficient , which reflects the effect of medium principal stress and the normal stress of the relevant surface on the material destroy degree, the ratio of tensile strength to compressed strength of the material, , and the damage variable
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Development of a redundant anthropomorphic hydraulically actuated manipulator with a roll–pitch–yaw spherical

《机械工程前沿（英文）》 2021年 第16卷 第4期   页码 698-710 doi: 10.1007/s11465-021-0646-2

摘要： The demand for redundant hydraulic manipulators that can implement complex heavy-duty tasks in unstructured areas is increasing; however, current manipulator layouts that remarkably differ from human arms make intuitive kinematic operation challenging to achieve. This study proposes a seven-degree-of-freedom (7-DOF) redundant anthropomorphic hydraulically actuated manipulator with a novel roll–pitch–yaw spherical wrist. A hybrid series–parallel mechanism is presented to achieve the spherical wrist design, which consists of two parallel linear hydraulic cylinders to drive the yaw/pitch 2-DOF wrist plate connected serially to the roll structure. Designed as a 1R PRRR-1S PU mechanism (“R”, “P”, “S”, and “U” denote revolute, prismatic, spherical, and universal joints, respectively; the underlined letter indicates the active joint), the 2-DOF parallel structure is partially decoupled to obtain simple forward/inverse kinematic solutions in which a closed-loop subchain “R PRR” is included. The 7-DOF manipulator is then designed, and its third joint axis goes through the spherical center to obtain closed-form inverse kinematic computation. The analytical inverse kinematic solution is drawn by constructing self-motion manifolds. Finally, a physical prototype is developed, and the kinematic analysis is validated via numerical simulation and test results.

关键词： hydraulic manipulator     inverse kinematic     redundant design     spherical wrist    

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Synthesis and electrocatalytic property of cubic and spherical nanoparticles of cobalt platinum alloys

Xiaowei TENG, Hong YANG,

《化学科学与工程前沿（英文）》 2010年 第4卷 第1期   页码 45-51 doi: 10.1007/s11705-009-0308-0

摘要： This paper describes the morphological control and electrocatalytic property of CoPt nanoparticles. Both cubic and spherical CoPt nanoparticles were made using cobalt carbonyl and platinum 2,4-pentanedionate under different reaction temperatures in the presence of capping reagents, which included adamantanecarboxylic acid and hexadecylamine. Effects of heterogeneous species on shape of the CoPt nanoparticles were examined by replacing cobalt carbonyl with silver acetylacetonate. Our results suggest that the formation of different shapes of CoPt particles could be attributed to the affinity between cobalt and platinum, and the effects of capping agents. The size and shape dependent electrocatalytic properties of these nanoparticles were examined based on the direct methanol oxidation reaction.

关键词： spherical     2     4-pentanedionate     adamantanecarboxylic     acetylacetonate     electrocatalytic    

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A study on bearing characteristic and failure mechanism of thin-walled structure of a prefabricated subway

Lianjin TAO; Cheng SHI; Peng DING; Sicheng LI; Shang WU; Yan BAO

《结构与土木工程前沿（英文）》 2022年 第16卷 第3期   页码 359-377 doi: 10.1007/s11709-022-0816-2

摘要： In order to study the bearing performance of a new type of prefabricated subway station structure (PSSS), firstly, a three-dimensional finite element model of the PSSS was established to study the nonlinear mechanics and deformation performance. Secondly, the bearing mechanism of a PSSS was investigated in detail. Finally, the development law of damages to a thin-walled prefabricated component and the failure evolution mechanism of a PSSS were discussed. The results showed that this new type of the PSSS had good bearing capacity. The top arch structure was a three-hinged arch bearing system, and the enclosure structure and the substructure were respectively used as the horizontal and vertical support systems of the three-hinged arch structure to ensure the integrity and stability of the overall structure. Moreover, the tongue-and-groove joints could effectively transmit the internal force between the components and keep the components deformed in harmony. The rigidity degradation of the PSSS caused by the accumulation of damages to the spandrel, hance, arch foot, and enclosure structure was the main reason of its loss of bearing capacity. The existing thin-walled components design had significant advantages in weight reduction, concrete temperature control, components hoisting, transportation and assembly construction, which achieved a good balance between safety, usability and economy.

关键词： prefabricated subway station     thin-walled components     finite element analysis     bearing characteristic     failure mechanism    

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标题 作者 时间 类型 操作

Elastic analysis of heterogeneous thick-walled spherical pressure vessels with parabolic varying properties

Keyhan KARAMI, Majid ABEDI, Mohammad ZAMANI NEJAD, Mohammad Hassan LOTFIAN

期刊论文

Demonstration project of safe and efficient mining operations in extra-thick coal seam

Jinhui WANG

期刊论文

Fixturing technology and system for thin-walled parts machining: a review

期刊论文

Dynamical research on spherical micro actuator with piezoelectric ceramic stacks drivers

ZHANG Ruihua, CHEN Haichu

期刊论文

Analysis on damage causes of built-in corridor in core rock-fill dam on thick overburden: A case study

Jia’ao YU; Zhenzhong SHEN; Zhangxin HUANG

期刊论文

Position-varying surface roughness prediction method considering compensated acceleration in milling of thin-walled

期刊论文

Endostatin specifically targets both tumor blood vessels and lymphatic vessels

Wei Zhuo, Yang Chen, Xiaomin Song, Yongzhang Luo

期刊论文

An analytical method for calculating torsional constants for arbitrary complicated thin-walled cross-sections

DU Baisong, GE Yaojun, ZHOU Zheng

期刊论文

Adsorption of toluene, ethylbenzene and xylene isomers on multi-walled carbon nanotubes oxidized by different

Fei YU, Jie MA, Yanqing WU

期刊论文

Improvement in growth yield of single-walled carbon nanotubes with narrow chirality distribution by pulse

Bin Xu, Toshiro Kaneko, Toshiaki Kato

期刊论文

Vibration analysis of multi-walled carbon nanotubes embedded in elastic medium

Pattabhi R. BUDARAPU,Sudhir Sastry YB,Brahmanandam JAVVAJI,D. Roy MAHAPATRA

期刊论文

Unified solution of limit loads of thick wall cylinder subject to external pressure considering strain

CHEN Changfu, XIAO Shujun, YANG Yu

期刊论文

Development of a redundant anthropomorphic hydraulically actuated manipulator with a roll–pitch–yaw spherical

期刊论文

Synthesis and electrocatalytic property of cubic and spherical nanoparticles of cobalt platinum alloys

Xiaowei TENG, Hong YANG,

期刊论文

A study on bearing characteristic and failure mechanism of thin-walled structure of a prefabricated subway

Lianjin TAO; Cheng SHI; Peng DING; Sicheng LI; Shang WU; Yan BAO

期刊论文