Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 8

年份

2023 1

2018 1

2015 1

2012 2

2006 1

2001 1

2000 1

展开︾

关键词

加速度传感器 1

变面积 1

比容 1

氟钽酸钾钠还原 1

电容 1

钽电容器 1

钽粉 1

展开︾

检索范围：

排序：展示方式：

Analysis and design of pulse frequency modulation dielectric barrier discharge for low power applications

Tang-tang GUO,Xing-liang LIU,Shi-qiang HAO,Chi ZHANG,Xiang-ning HE

《信息与电子工程前沿（英文）》 2015年第16卷第3期页码 249-258 doi: 10.1631/FITEE.1400185

摘要： For low power dielectric barrier discharge (DBD) used in small-size material treatment or portable devices, highstep transformer parasitic capacitance greatly influences the performance of the resonant converter as it is of the same order of magnitude as the equivalent capacitance of DBD load. In this paper, steady-state analysis of the low power DBD is presented, considering the inevitable parasitic capacitance of the high-step transformer. The rectifier-compensated first harmonic approximation (RCFHA) is applied to linearize the equivalent load circuit of DBD at low frequency and the derived expressions are accurate and convenient for the analysis and design of the power supply. Based on the proposed linear equivalent load circuit, the influence of transformer parasitic capacitance on the key parameters, including the frequency range and the applied electrode voltage, is discussed when the power is regulated with pulse frequency modulation (PFM). Also, a design procedure is presented based on the derived expressions. A prototype is constructed according to the design results and the accuracy of the design is verified by experimental results.

关键词： Dielectric barrier discharge Rectifier-compensated first harmonic approximation Parasitic capacitance Power converter design

HTML PDF 收藏

novel method of plotting sensor sensitivity field and image reconstruction algorithm for electrical capacitance

CHEN De-yun, YANG Cong-jing, ZHENG Gui-bin, YU Xiao-yang, SUN Li-juan

《机械工程前沿（英文）》 2006年第1卷第2期页码 242-247 doi: 10.1007/s11465-006-0008-0

摘要： Sensor sensitivity field in electrical capacitance tomography is affected by the distribution of multiphase medium, which is the peculiarity of soft field. This brings great difficulty for image reconstruction. To improve the quality of image reconstruction, it is important to analyze the distribution of the sensitivity field. In this article, using the finite element method, we expound a kind of novel plotting pattern to field, which is the distribution of sensitivity field through computer simulation. From experiments and results of sensitivity field analysis, a novel method of image reconstruction based on genetic algorithms is presented. The finite element model is correct and simulation result is fine by adopting unequal interval plotting patterns. At the same time, the result of image reconstruction has high precision.

关键词： multiphase unequal interval capacitance tomography pattern sensitivity

HTML PDF 收藏

Parasitic rotation evaluation and avoidance of 3-UPU parallel mechanism

Haibo QU, Yuefa FANG, Sheng GUO

《机械工程前沿（英文）》 2012年第7卷第2期页码 210-218 doi: 10.1007/s11465-012-0317-4

摘要：

Based on the prototype of 3-UPU (universal-prismatic-universal joint) parallel mechanism proposed by Tsai [ ], the parasitic rotation evaluation is performed and calculated the bound of instability of SNU Seoul National University 3-UPU parallel mechanism. Through analysis of the terminal constraint system of the 3-UPU parallel mechanism, the equation about the parasitic rotation and limited clearance is presented. Then the norm of possible parasitic rotation is employed to evaluate the mechanism stability with limited clearance. The higher this number the worst is the pose, the lower it is the best it is. And the contour atlas of parasitic rotation is obtained, which can be used for further analysis and design. With the practice experiment result of SUN 3-UPU parallel mechanism, we find it’s bound of instability, which indicates there will appear the parasitic rotation when the number exceeds the bound. Finally, the method for avoidance of possible parasitic motions is presented by adding redundantly actuated limbs.

关键词： parallel mechanism 3-UPU (universal-prismatic-universal joint) parasitic motions limited clearance redundantly actuated limbs

HTML PDF 收藏

Harvesting biomechanical energy in the walking by shoe based on liquid metal magnetohydrodynamics

Dan DAI, Jing LIU, Yixin ZHOU

《能源前沿（英文）》 2012年第6卷第2期页码 112-121 doi: 10.1007/s11708-012-0186-x

摘要： A liquid metal magnetohydrodynamics generation system (LMMGS) was proposed and demonstrated in this paper for collecting parasitic power in shoe while walking. Unlike the conventional shoe-mounted human power harvesters that use solid coil and gear mechanism, the proposed system employs liquid metal (Ga In Sn ) as energy carrier, where no moving part is requested in magnetohydrodynamics generators (MHGs). While walking with the LMMGS, the foot alternately presses the two liquid metal pumps (LMPs) which are respectively placed in the front and rear of the sole. As a result, the liquid metal in the LMPs (LMP I and II) is extruded and flows through the MHGs (MHG I and II) in which electricity is produced. For a comparison, three types of LMMGSs (LMMGS A, B and C) were built where all the parts are the same except for the LMPs. Furthermore, performances of these LMMGSs with different volume of injected liquid metal were tested respectively. Experimental results reveal that both the output voltage and power of the LMMGS increase with the volume of injected liquid metal and the size of the LMPs. In addition, a maximum output power of 80 mW is obtained by the LMMGS C with an efficiency of approximately 1.3%. Given its advantages of no side effect, light weight, small size and reliability, The LMMGS is well-suited for powering the wearable and implantable micro/nano device, such as wearable sensors, drug pumps and so on.

关键词： human energy harvesting liquid metal wearable magnetohydrodynamics generator parasitic power in shoe

HTML PDF 收藏

变面积结构微机械电容式加速度传感器

李宝清,陆德仁,王渭源

《中国工程科学》 2000年第2卷第2期页码 36-40

摘要：

文章首次报道了一种基于面积可变电容结构的微机械加速度传感器。质量块呈栅状结构，由悬臂梁支撑。两组交叉放置的定电极位于质量块的正下方。在惯性力的作用下，质量块呈平行于衬底水平移动，引起由质量块的栅与定电极的叉指构成的差分电容变化。通过测量差分电容的变化，可以得到加速信号的大小。理论分析表明加速度响应信号随面积呈线性变化，而与质量块及定电极的间距无关。加速度传感器的制作采用了基于金属电镀的准LIGA技术，设计量程为20m/s²。测量结果表明，加速度传感器量程为20m/s²，灵敏度为58.1mV/(m·s^-2)，非线性为4%FS。讨论了器件线性度不够理想的原因。

关键词：电容加速度传感器变面积

HTML PDF 收藏

世界钽粉生产工艺的发展

何季麟

《中国工程科学》 2001年第3卷第12期页码 85-89

摘要：

论述了国内外电容器级高压钽粉、中压钽粉、高比容钽粉的生产工艺发展过程。在钽粉生产工艺发展过程中，各种先进的装备被应用，各钽粉生产厂家围绕着钽粉比容的提高，杂质含量的降低，物理性能的优化等综合性能的改善，不断开发出新工艺、新技术，使钽粉适应并推动着钽电容器的发展。

关键词：钽粉钽电容器比容氟钽酸钾钠还原

HTML PDF 收藏

Fast forward kinematics algorithm for real-time and high-precision control of the 3-RPS parallel mechanism

Yue WANG, Jingjun YU, Xu PEI

《机械工程前沿（英文）》 2018年第13卷第3期页码 368-375 doi: 10.1007/s11465-018-0519-5

摘要：

A new forward kinematics algorithm for the mechanism of 3-RPS (R: Revolute; P: Prismatic; S: Spherical) parallel manipulators is proposed in this study. This algorithm is primarily based on the special geometric conditions of the 3-RPS parallel mechanism, and it eliminates the errors produced by parasitic motions to improve and ensure accuracy. Specifically, the errors can be less than 10^-6 . In this method, only the group of solutions that is consistent with the actual situation of the platform is obtained rapidly. This algorithm substantially improves calculation efficiency because the selected initial values are reasonable, and all the formulas in the calculation are analytical. This novel forward kinematics algorithm is well suited for real-time and high-precision control of the 3-RPS parallel mechanism.

关键词： 3-RPS parallel mechanism forward kinematics numerical algorithm parasitic motion

HTML PDF 收藏

Boron and nitrogen co-doped porous carbon derived from sodium alginate enhanced capacitive deionization for water purification

《化学科学与工程前沿（英文）》 2023年第17卷第12期页码 2014-2024 doi: 10.1007/s11705-023-2346-4

摘要： Capacitive deionization can alleviate water shortage and water environmental pollution, but performances are greatly determined by the electrochemical and desalination properties of its electrode materials. In this work, B and N co-doped porous carbon with micro-mesoporous structures is derived from sodium alginate by a carbonization, activation, and hydrothermal doping process, which exhibits large specific surface area (2587 m²·g^‒1) and high specific capacitance (190.7 F·g^‒1) for adsorption of salt ions and heavy metal ions. Furthermore, the materials provide a desalination capacity of 26.9 mg·g⁻¹ at 1.2 V in 500 mg·L^‒1 NaCl solution as well as a high removal capacity (239.6 mg·g^‒1) and adsorption rate (7.99 mg·g^‒1·min^‒1) for Pb²⁺ with an excellent cycle stability. This work can pave the way to design low-cost porous carbon with high-performances for removal of salt ions and heavy metal ions.

关键词： capacitance deionization porous carbon B/N co-doping heavy metal ions water purification