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期刊论文 33

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Precise semi-analytical inverse kinematic solution for 7-DOF offset manipulator with arm angle optimization

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 435-450 doi: 10.1007/s11465-021-0630-x

摘要: Seven-degree-of-freedom redundant manipulators with link offset have many advantages, including obvious geometric significance and suitability for configu-ration control. Their configuration is similar to that of the experimental module manipulator (EMM) in the Chinese Space Station Remote Manipulator System. However, finding the analytical solution of an EMM on the basis of arm angle parameterization is difficult. This study proposes a high-precision, semi-analytical inverse method for EMMs. Firstly, the analytical inverse kinematic solution is established based on joint angle parameterization. Secondly, the analytical inverse kinematic solution for a non-offset spherical–roll–spherical (SRS) redundant manipulator is derived based on arm angle parameterization. The approximate solution of the EMM is calculated in accordance with the relationship between the joint angles of the EMM and the SRS manipulator. Thirdly, the error is corrected using a numerical method through the analytical inverse solution based on joint angle parameterization. After selecting the stride and termination condition, the precise inverse solution is computed for the EMM based on arm angle parameterization. Lastly, case solutions confirm that this method has high precision, and the arm angle parameterization method is superior to the joint angle parameterization method in terms of parameter selection.

关键词: 7-DOF redundant manipulator     inverse kinematics     semi-analytical     arm angle     link offset    

Flow and heat transfer in compact offset strip fin surfaces

DONG Junqi, CHEN Jiangping, CHEN Zhijiu

《能源前沿(英文)》 2008年 第2卷 第3期   页码 291-297 doi: 10.1007/s11708-008-0061-y

摘要: Experimental studies of air-side heat transfer and pressure drop characteristics of offset strip fins and flat tube heat exchangers were performed. A series of tests were conducted for 9 heat exchangers with different fin space, fi

关键词: different     air-side     transfer     pressure     offset    

Effects of environmental media on the transmission of an inductive link in wireless microsystems

Lei DONG, Li-Feng WANG, Qing-An HUANG

《机械工程前沿(英文)》 2017年 第12卷 第4期   页码 554-556 doi: 10.1007/s11465-017-0450-1

摘要:

An inductive link between two magnetically coupled coils in wireless microsystems is modeled by considering an additional parasitic capacitive link to describe the effect of environmental media. With a system of inductor-capacitor passive wireless sensors, the effects of environmental media are studied theoretically and experimentally for the first time. Results suggest that the capacitive link is non-negligible when the distance between the two coupled coils is comparable with the coupling area, particularly when the environmental medium has a large dielectric constant.

关键词: capacitive link     monitoring correction     passive wireless sensor    

Contact of surfaces and contact characteristics of offset surfaces

CAO Lixin, GONG Hu, LIU Jian

《机械工程前沿(英文)》 2008年 第3卷 第3期   页码 318-324 doi: 10.1007/s11465-008-0067-5

摘要: Based on differential geometry, the contact problems of two surfaces are discussed in this paper. The relationship between the contact status of two surfaces and that of offset surfaces are also analyzed. For a 5-axis NC machining, some research such as optimization of cutter location and calculation of the geometrical cusp height are important. The research results indicate that the relative normal curvature is an important geometrical invariant for describing the contact state of two surfaces. For point contact two surfaces, the calculation equation for the second order remained error is given. For line contact two surfaces, the condition of the second order line contact is that the principal directions and curvatures of the two surfaces are the same along the contact curve. If two surfaces keep the second order line contact, their two offset surfaces will also keep the second order line contact, and their third order remained errors are also uniform with that of the two offset surfaces.

关键词: relative     important geometrical     relationship     geometrical invariant     calculation    

Polyhedral linkages obtained as assemblies of planar link groups

GÖkhan KİPER, Eres SÖYLEMEZ

《机械工程前沿(英文)》 2013年 第8卷 第1期   页码 3-9 doi: 10.1007/s11465-013-0363-6

摘要:

The study aims to devise means of obtaining polyhedral linkages for homothetic deployment of polyhedral shapes by embedding planar link groups in faces of the polyhedral shape of interest. The questions of which polyhedral shapes may be suitable for such a purpose and what are the compatibility conditions for spatially assembling planar link groups are addressed. Homohedral and tangential polyhedral shapes are found to be suitable for the task and some examples of linkages are worked out.

关键词: polyhedral linkages     homothety     homohedra     tangential polyhedra    

DFIG sliding mode control fed by back-to-back PWM converter with DC-link voltage control for variable

Youcef BEKAKRA,Djilani BEN ATTOUS

《能源前沿(英文)》 2014年 第8卷 第3期   页码 345-354 doi: 10.1007/s11708-014-0330-x

摘要: This paper proposes an indirect power control of doubly fed induction generator (DFIG) with the rotor connected to the electric grid through a back-to-back pulse width modulation (PWM) converter for variable speed wind power generation. Appropriate state space model of the DFIG is deduced. An original control strategy based on a variable structure control theory, also called sliding mode control, is applied to achieve the control of the active and reactive power exchanged between the stator of the DFIG and the grid. A proportional-integral-(PI) controller is used to keep the DC-link voltage constant for a back-to-back PWM converter. Simulations are conducted for validation of the digital controller operation using Matlab/Simulink software.

关键词: doubly fed induction generator (DFIG)     wind turbine     back-to-back pulse width modulation (PWM)     DC-link voltage     sliding mode control    

余弦忆导忆阻系统周期变化初值位移调控行为 Regular Papers

Mo CHEN, Xue REN, Hua-gan WU, Quan XU, Bo-cheng BAO

《信息与电子工程前沿(英文)》 2019年 第20卷 第12期   页码 1706-1716 doi: 10.1631/FITEE.1900360

摘要: 利用一种新型余弦忆导理想忆阻,构造一个四维忆阻系统。由于忆导函数特殊的非线性,忆阻系统具有沿忆阻内部状态变量坐标轴分布的线平衡点集(0, 0, 0, δ),且平衡点集稳定性随δ变化而周期性演化。数值仿真揭示了忆阻系统非线性、一维的初值位移调控行为,它不仅可由忆阻状态初值触发,也可由其他两个系统状态初值引发。特别地,在位移调控路线上,可以观测到多种具有不同位置和拓扑结构的共存吸引子。通过PSIM电路仿真对该特殊动力学特性进行了验证。

关键词: 初值位移调控;忆阻系统;忆导;线平衡点集    

Rosin side chain type catalyst-free vitrimers with high cross-link density, mechanical strength, and

《化学科学与工程前沿(英文)》 2023年 第17卷 第9期   页码 1267-1279 doi: 10.1007/s11705-022-2291-7

摘要: The emergence of vitrimer, a new class of polymer materials can address the problem of recyclability, reprocess ability and recyclability of thermosetting plastics. Rosin, a natural product, is an ideal raw material for the preparation of polymers in a more sustainable way. Nevertheless, due to the huge steric hindrance caused by the hydrogenated phenanthrene ring structure, the cross-link density of materials is frequently lowered. In this study, hydrogenated rosin was adopted for preparing hydrogenated rosin side-chain type diacids, which were reacted with mixed epoxy to obtain rosin side-chain type vitrimers. It was completely characterized by differential scanning calorimetry test, thermogravimetric analysis, shape memory test and self-healing test. The prepared vitrimers exhibited good self-healing properties, excellent heat resistance (Td = 352 °C) as well as high mechanical properties (tensile strength of 46.75 MPa). The tricyclic diterpene structure of rosin was introduced into the side chain in order to avoid the reduction of cross-link density resulting from the huge steric hindrance of the rigid tricyclic hydrophenylene skeleton. Vitrimers can undergo dynamic transesterification reaction without external catalysts due to the autocatalytic effect of tertiary amines from epoxy. Moreover, our work expanded the application field of rosin, increased the added value of rosin, and provided a novel method for preparing rosin-based vitrimers with ideal properties.

关键词: vitrimers     rosin     catalyst-free     high mechanical properties     dynamic transesterification reaction    

基于网络传输特性的链路重要性评价方法

姜禹,胡爱群,何明

《中国工程科学》 2009年 第11卷 第9期   页码 64-67

摘要:

提出了一种基于网络传输特性的链路重要性评价方法, 根据链路在网络所有节点相互通信的最短路径中的使用频度来评价链路重要性,最重要链路的使用频度最高。该方法不需要像目前的链路重要性评价方法那样进行链路收缩和删除,直接反映了链路对整个网络通信的贡献大小,可以判断通信网中任意两条链路的相对重要性。算法分析和实验仿真表明,文章算法克服了目前的评价方法存在的问题,给出了更直观合理的通信网链路重要性评价准则。

关键词: 通信网     链路重要性     最短路径     串联链路    

Impact of selection of DC base values and DC link control strategies on sequential AC-DC power-flow convergence

Shagufta KHAN,Suman BHOWMICK

《能源前沿(英文)》 2015年 第9卷 第4期   页码 399-412 doi: 10.1007/s11708-015-0374-6

摘要: This paper demonstrates the convergence of the integrated AC-DC power-flow algorithm as affected by the selection of different base values for the DC quantities and adoption of different control strategies for the DC link. For power-flow modeling of integrated AC-DC systems, the base values of the various DC quantities can be defined in several ways, giving rise to different sets of per-unit system equations. It is observed that different per-unit system models affect the convergence of the power-flow algorithm differently. In a similar manner, the control strategy adopted for the DC link also affects the power-flow convergence. The sequential method is used to solve the DC variables in the Newton Raphson (NR) power flow model, where AC and DC systems are solved separately and are coupled by injecting an equivalent amount of real and reactive power at the terminal AC buses. Now, for a majority of the possible control strategies, the equivalent real and reactive power injections at the concerned buses can be computed a-priori and are independent of the NR iterative loop. However, for a few of the control strategies, the equivalent reactive power injections cannot be computed a-priori and need to be computed in every NR iteration. This affects the performance of the iterative process. Two different per-unit system models and six typical control strategies are taken into consideration. This is validated by numerous case studies conducted on the IEEE 118-bus and 300-bus test systems.

关键词: AC-DC power-flow     Newton-Raphson method     high voltage direct current (HVDC) control strategy    

Removable Dyes—The Missing Link for In-Depth N-glycan Analysis via Multi-Method Approaches

Samanta Cajic,René Hennig,Valerian Grote,Udo Reichl,Erdmann Rapp,

《工程(英文)》 doi: 10.1016/j.eng.2023.02.016

摘要: As the roles of glycans in health and disease continue to be unraveled, it is becoming apparent that glycans’ immense complexity cannot be ignored. To fully delineate glycan structures, we developed an integrative approach combining a set of cost-effective, widespread, and easy-to-handle analytical methods. The key feature of our workflow is the exploitation of a removable fluorescent label—exemplified by 9-fluorenylmethyl chloroformate (Fmoc)—to bridge the gap between diverse glycoanalytical methods, especially multiplexed capillary gel electrophoresis with laser-induced fluorescence detection (xCGE-LIF) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Through the detailed structural analysis of selected, dauntingly complex N-glycans from chicken ovalbumin, horse serum, and bovine transferrin, we illustrate the capabilities of the presented strategy. Moreover, this approach “visualizes” N-glycans that have been difficult to identify thus far—such as the sulfated glycans on human immunoglobulin A—including minute changes in glycan structures, potentially providing useful new targets for biomarker discovery.

关键词: Glycoproteins     N-glycans     Reversible labeling     Hydrophilic interaction liquid chromatography     Capillary gel electrophoresis     Mass spectrometry    

一种有效的无线传感器网络失效链路定位方法 Article

Wen-yan CUI, Xiang-ru MENG, Bin-feng YANG, Huan-huan YANG, Zhi-yuan ZHAO

《信息与电子工程前沿(英文)》 2017年 第18卷 第5期   页码 689-707 doi: 10.1631/FITEE.1601247

摘要: 由于无线传感器网络中经常发生故障,网络故障管理对其维持正常运行状态非常重要。当前的故障定位方法通常先推断最有可能故障集,然后给出故障假设集。然而假设集中往往含有大量实际并未发生的故障。推断集中的冗余信息会大大加重故障推断的计算量,从而降低评估精度且增加故障定位时间。为了解决这个问题,本文提出了基于条件信息熵的冗余消除算法,该算法可以在保留核心信息的基础上消除大部分冗余信息。此外,还提出一种可以精确反映故障关系的概率关联故障模型,并为非确定性故障传播构建模型。通过一系列数学推导,本文将故障定位问题转化为覆盖件问题进行求解,并提出启发式算法推导故障假设集。在仿真环境和真实平台上验证了提出的方法相比现有故障定位方法的有效性。

关键词: 失效链路定位;冗余消除算法;覆盖集;无线传感器网络;网络诊断    

手机直连卫星,未来可期

Mitch Leslie

《工程(英文)》 2023年 第28卷 第9期   页码 4-6 doi: 10.1016/j.eng.2023.07.003

Research on the valveless piezoelectric pump with Y-shape pipes

ZHANG Jianhui, LU Jizhuang, XIA Qixiao

《机械工程前沿(英文)》 2007年 第2卷 第2期   页码 144-151 doi: 10.1007/s11465-007-0024-8

摘要: A piezoelectric pump with its Y-shape elements is presented. Two Y-shape pipes are fixed outside the chamber serving as an inlet and outlet, with the chamber and a piezoelectric vibrator being the actor. The pump has the potential to be miniaturized and integrated. Eddies occurring in the Y-shape elements are smaller, which is beneficial for the transport of living cells or long-link macromolecules. In this paper, the structure of the pump is first presented. Then, the equations on the change in volume and the mean pressure in the chamber are established, as well as the relation between the flow rate and the working frequency of the piezoelectric vibrator. Moreover, the relation between the mean pressure in the chamber and the working frequency of the piezoelectric vibrator is established. Finally, experiments are carried out to test the characteristics of the pump and to verify the correction of the theory on this pump.

关键词: chamber serving     beneficial     working frequency     long-link     correction    

协议分析仪2Mb/s高速信令处理模块

刘志辉

《中国工程科学》 2002年 第4卷 第2期   页码 79-85

摘要:

为了满足2 Mb/s高速信令的测试要求,开发了2 Mb/s高速信令协议分析仪信令处理模块。信令处理模块分为硬件系统和软件系统两部分。介绍了开发2 Mb/s高速信令协议分析仪的意义,使用2 Mb/s高速信令链路的优势,信令处理模块的设计原理和功能。介绍嵌入式处理器和实时操作系统的相关内容。

关键词: 协议分析仪     2 Mb/s高速信令     嵌入式处理器     实时操作系统    

标题 作者 时间 类型 操作

Precise semi-analytical inverse kinematic solution for 7-DOF offset manipulator with arm angle optimization

期刊论文

Flow and heat transfer in compact offset strip fin surfaces

DONG Junqi, CHEN Jiangping, CHEN Zhijiu

期刊论文

Effects of environmental media on the transmission of an inductive link in wireless microsystems

Lei DONG, Li-Feng WANG, Qing-An HUANG

期刊论文

Contact of surfaces and contact characteristics of offset surfaces

CAO Lixin, GONG Hu, LIU Jian

期刊论文

Polyhedral linkages obtained as assemblies of planar link groups

GÖkhan KİPER, Eres SÖYLEMEZ

期刊论文

DFIG sliding mode control fed by back-to-back PWM converter with DC-link voltage control for variable

Youcef BEKAKRA,Djilani BEN ATTOUS

期刊论文

余弦忆导忆阻系统周期变化初值位移调控行为

Mo CHEN, Xue REN, Hua-gan WU, Quan XU, Bo-cheng BAO

期刊论文

Rosin side chain type catalyst-free vitrimers with high cross-link density, mechanical strength, and

期刊论文

基于网络传输特性的链路重要性评价方法

姜禹,胡爱群,何明

期刊论文

Impact of selection of DC base values and DC link control strategies on sequential AC-DC power-flow convergence

Shagufta KHAN,Suman BHOWMICK

期刊论文

Removable Dyes—The Missing Link for In-Depth N-glycan Analysis via Multi-Method Approaches

Samanta Cajic,René Hennig,Valerian Grote,Udo Reichl,Erdmann Rapp,

期刊论文

一种有效的无线传感器网络失效链路定位方法

Wen-yan CUI, Xiang-ru MENG, Bin-feng YANG, Huan-huan YANG, Zhi-yuan ZHAO

期刊论文

手机直连卫星,未来可期

Mitch Leslie

期刊论文

Research on the valveless piezoelectric pump with Y-shape pipes

ZHANG Jianhui, LU Jizhuang, XIA Qixiao

期刊论文

协议分析仪2Mb/s高速信令处理模块

刘志辉

期刊论文