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 164

会议视频 8

年份

2023 12

2022 15

2021 16

2020 13

2019 17

2018 7

2017 14

2016 7

2015 9

2014 6

2013 2

2012 4

2011 6

2010 2

2009 7

2008 4

2007 6

2006 2

2005 1

2004 3

展开︾

关键词

光纤通信 3

人工智能 2

光纤传感技术 2

波分复用 2

神经网络 2

AF/PSTM 1

ANSYS 1

LMS 1

NNI 1

PIC16F877A 1

PSTM图像分解 1

PSTM数值模拟 1

PSTM消假像 1

Q值监测 1

RS—485总线 1

UNI 1

VO₂薄膜 1

Weibull分布杂波 1

XeF(C-A)激光 1

展开︾

检索范围：

排序：展示方式：

提高光流估计性能的渐进性高斯多维预滤波方法的研究

付昀,徐维朴

《中国工程科学》 2004年第6卷第12期页码 56-61

摘要：

基于光流计算方法统一框架理论，研究了一种利用高斯多维滤波器的渐进性和时空性提高光流估计性能的有效方法。在保持现有光流计算方法的前提下，通过调节时间维和空间维的方差参数，改变时空预滤波和光滑效果，突出时间混叠和光流主信息，从而提高重构视频序列的信噪比。试验中以标准的Flower Garden和Football序列的前50帧作为参考图像序列，以LK算法为参考光流算法。结果显示，滤波窗口为5×5时的最佳时间方差参数为0.4，最佳空间方差参数为［1.6，2.0］；加入高斯多维预滤波前后利用光流场重构图像的平均峰值信噪比PSNR提高2.572dB，提高幅度为13.6%。

关键词：光流计算高斯多维滤波峰值信噪比运动估计

HTML PDF 收藏

Application of metal oxides-based nanofluids in PV/T systems: a review

《能源前沿（英文）》 2022年第16卷第3期页码 397-428 doi: 10.1007/s11708-021-0758-8

摘要： Having the wide application of metal oxides in energy technologies, in recent years, many researchers tried to increase the performance of the PV/T system by using metal oxide-based nanofluids (NFs) as coolants or optical filters or both at the same time. This paper summarizes recent research activities on various metal oxides (Al₂O₃, TiO₂, SiO₂, Fe₃O₄, CuO, ZnO, MgO)-based NFs performance in the PV/T system regarding different significant parameters, e.g., thermal conductivity, volume fraction, mass flowrate, electrical, thermal and overall efficiency, etc. By conducting a comparative study among the metal oxide-based NFs, Al₂O₃/SiO₂-water NFs are mostly used to achieve maximum performance. The Al₂O₃-water NF has a prominent heat transfer feature with a maximum electrical efficiency of 17%, and a maximum temperature reduction of PV module of up to 36.9°C can be achieved by using the Al₂O₃-water NF as a coolant. Additionally, studies suggest that the PV cell’s efficiency of up to 30% can be enhanced by using a solar tracking system. Besides, TiO₂-water NFs have been proved to have the highest thermal efficiency of 86% in the PV/T system, but TiO₂ nanoparticles could be hazardous for human health. As a spectral filter, SiO₂-water NF at a size of 5 nm and a volume fraction of 2% seems to be very favorable for PV/T systems. Studies show that the combined use of NFs as coolants and spectral filters in the PV/T system could provide a higher overall efficiency at a cheaper rate. Finally, the opportunities and challenges of using NFs in PV/T systems are also discussed.

关键词： metal oxide nanofluids (NFs) nanoparticles (NPs) optical filter PV/T systems solar energy

HTML PDF 收藏

Development of surface reconstruction algorithms for optical interferometric measurement

Dongxu WU, Fengzhou FANG

《机械工程前沿（英文）》 2021年第16卷第1期页码 1-31 doi: 10.1007/s11465-020-0602-6

摘要： Optical interferometry is a powerful tool for measuring and characterizing areal surface topography in precision manufacturing. A variety of instruments based on optical interferometry have been developed to meet the measurement needs in various applications, but the existing techniques are simply not enough to meet the ever-increasing requirements in terms of accuracy, speed, robustness, and dynamic range, especially in on-line or on-machine conditions. This paper provides an in-depth perspective of surface topography reconstruction for optical interferometric measurements. Principles, configurations, and applications of typical optical interferometers with different capabilities and limitations are presented. Theoretical background and recent advances of fringe analysis algorithms, including coherence peak sensing and phase-shifting algorithm, are summarized. The new developments in measurement accuracy and repeatability, noise resistance, self-calibration ability, and computational efficiency are discussed. This paper also presents the new challenges that optical interferometry techniques are facing in surface topography measurement. To address these challenges, advanced techniques in image stitching, on-machine measurement, intelligent sampling, parallel computing, and deep learning are explored to improve the functional performance of optical interferometry in future manufacturing metrology.

关键词： surface topography measurement optical interferometry coherence envelope phase-shifting algorithm

HTML PDF 收藏

Precision glass molding: Toward an optimal fabrication of optical lenses

Liangchi ZHANG,Weidong LIU

《机械工程前沿（英文）》 2017年第12卷第1期页码 3-17 doi: 10.1007/s11465-017-0408-3

摘要：

It is costly and time consuming to use machining processes, such as grinding, polishing and lapping, to produce optical glass lenses with complex features. Precision glass molding (PGM) has thus been developed to realize an efficient manufacture of such optical components in a single step. However, PGM faces various technical challenges. For example, a PGM process must be carried out within the super-cooled region of optical glass above its glass transition temperature, in which the material has an unstable non-equilibrium structure. Within a narrow window of allowable temperature variation, the glass viscosity can change from 10⁵ to 10¹² Pa·s due to the kinetic fragility of the super-cooled liquid. This makes a PGM process sensitive to its molding temperature. In addition, because of the structural relaxation in this temperature window, the atomic structure that governs the material properties is strongly dependent on time and thermal history. Such complexity often leads to residual stresses and shape distortion in a lens molded, causing unexpected changes in density and refractive index. This review will discuss some of the central issues in PGM processes and provide a method based on a manufacturing chain consideration from mold material selection, property and deformation characterization of optical glass to process optimization. The realization of such optimization is a necessary step for the Industry 4.0 of PGM.

关键词： precision glass molding optical lens constitutive modeling optimization manufacturing chain Industry 4.0

HTML PDF 收藏

国外光纤光纤带和带状光缆技术的最新发展

刘良炎

《中国工程科学》 2001年第3卷第9期页码 86-94

摘要：

综合介绍了近年国外关于低衰耗的色散补偿光纤，非零色散位移光纤，用于恶劣环境的碳涂覆和氮化硅涂覆光纤的研究；光纤带制造技术包括光纤带的结构、涂层、性能、生产工艺，大芯数光纤带状光缆包括层绞式松管、中心松管式、骨架式、干缆芯带状光缆的设计制造技术的最新进展。

关键词：光纤通信低衰耗光纤光纤带光纤带状光缆

HTML PDF 收藏

成像光学工程面临的光学问题

潘君骅

《中国工程科学》 2000年第2卷第3期页码 32-35

摘要：

文章简单论述了现代成像光学主要领域的情况，指出非球面反射系统是发展的必然趋势。讨论了加工与检验方面的基本情况及应着重深人研究的问题。对镜坯材料也提了一点看法。

关键词：成像光学非球面反射镜光学设计光学加工与检验

HTML PDF 收藏

Effects of critical geometric parameters on the optical performance of a conical cavity receiver

Hu XIAO, Yanping ZHANG, Cong YOU, Chongzhe ZOU, Quentin FALCOZ

《能源前沿（英文）》 2019年第13卷第4期页码 673-683 doi: 10.1007/s11708-019-0630-2

摘要： The optical performance of a receiver has a great influence on the efficiency and stability of a solar thermal power system. Most of the literature focuses on the optical performance of receivers with different geometric shapes, but less research is conducted on the effects of critical geometric parameters. In this paper, the commercial software TracePro was used to investigate the effects of some factors on a conical cavity receiver, such as the conical angle, the number of loops of the helical tube, and the distance between the focal point of the collector and the aperture. These factors affect the optical efficiency, the maximum heat flux density, and the light distribution in the conical cavity. The optical performance of the conical receiver was studied and analyzed using the Monte Carlo ray tracing method. To make a reliable simulation, the helical tube was attached to the inner wall of the cavity in the proposed model. The results showed that the amount of light rays reaching the helical tube increases with the increasing of the conical angle, while the optical efficiency decreases and the maximum heat flux density increases. The increase in the number of loops contributed to an increase in the optical efficiency and a uniform light distribution. The conical cavity receiver had an optimal optical performance when the focal point of the collector was near the aperture.

关键词： parabolic collector conical cavity receiver critical geometric parameters optical performance

HTML PDF 收藏

Implicit Heaviside filter with high continuity based on suitably graded THB splines

《机械工程前沿（英文）》 2022年第17卷第1期页码 14-14 doi: 10.1007/s11465-021-0670-2

摘要： The variable density topology optimization (TO) method has been applied to various engineering fields because it can effectively and efficiently generate the conceptual design for engineering structures. However, it suffers from the problem of low continuity resulting from the discreteness of both design variables and explicit Heaviside filter. In this paper, an implicit Heaviside filter with high continuity is introduced to generate black and white designs for TO where the design space is parameterized by suitably graded truncated hierarchical B-splines (THB). In this approach, the fixed analysis mesh of isogeometric analysis is decoupled from the design mesh, whose adaptivity is implemented by truncated hierarchical B-spline subjected to an admissible requirement. Through the intrinsic local support and high continuity of THB basis, an implicit adaptively adjusted Heaviside filter is obtained to remove the checkboard patterns and generate black and white designs. Threefold advantages are attained in the proposed filter: a) The connection between analysis mesh and adaptive design mesh is easily established compared with the traditional adaptive TO method using nodal density; b) the efficiency in updating design variables is remarkably improved than the traditional implicit sensitivity filter based on B-splines under successive global refinement; and c) the generated black and white designs are preliminarily compatible with current commercial computer aided design system. Several numerical examples are used to verify the effectiveness of the proposed implicit Heaviside filter in compliance and compliant mechanism as well as heat conduction TO problems.

关键词： topology optimization truncated hierarchical B-spline isogeometric analysis black and white designs Heaviside filter

HTML PDF 收藏

Recent advancements in optical microstructure fabrication through glass molding process

Tianfeng ZHOU,Xiaohua LIU,Zhiqiang LIANG,Yang LIU,Jiaqing XIE,Xibin WANG

《机械工程前沿（英文）》 2017年第12卷第1期页码 46-65 doi: 10.1007/s11465-017-0425-2

摘要：

Optical microstructures are increasingly applied in several fields, such as optical systems, precision measurement, and microfluid chips. Microstructures include microgrooves, microprisms, and microlenses. This paper presents an overview of optical microstructure fabrication through glass molding and highlights the applications of optical microstructures in mold fabrication and glass molding. The glass-mold interface friction and adhesion are also discussed. Moreover, the latest advancements in glass molding technologies are detailed, including new mold materials and their fabrication methods, viscoelastic constitutive modeling of glass, and microstructure molding process, as well as ultrasonic vibration-assisted molding technology.

关键词： optical microstructure microgroove microlens glass molding process single-point diamond cutting

HTML PDF 收藏

Anovel approach of noise statistics estimate using H∞ filter in target tracking

Xie WANG,Mei-qin LIU,Zhen FAN,Sen-lin ZHANG

《信息与电子工程前沿（英文）》 2016年第17卷第5期页码 449-457 doi: 10.1631/FITEE.1500262

摘要： Noise statistics are essential for estimation performance. In practical situations, however, a priori information of noise statistics is often imperfect. Previous work on noise statistics identification in linear systems still requires initial prior knowledge of the noise. A novel approach is presented in this paper to solve this paradox. First, we apply the H∞ filter to obtain the system state estimates without the common assumptions about the noise in conventional adaptive filters. Then by applying state estimates obtained from the H∞ filter, better estimates of the noise mean and covariance can be achieved, which can improve the performance of estimation. The proposed approach makes the best use of the system knowledge without a priori information with modest computation cost, which makes it possible to be applied online. Finally, numerical examples are presented to show the efficiency of this approach.

关键词： Noise estimate H∞ filter Target tracking

HTML PDF 收藏

Isolation and application of an ibuprofen-degrading bacterium to a biological aerated filter for the

Bingjie Xu, Gang Xue, Xing Yang

《环境科学与工程前沿（英文）》 2018年第12卷第5期 doi: 10.1007/s11783-018-1080-5

摘要：

• An ibuprofen-degrading strain, Serratia marcescens BL1, was isolated and identified.

• The effects of various factors on ibuprofen degradation by BL1 were evaluated.

• Strain BL1 was applied to a laboratory-scale biological aerated filter system.

• Strain BL1 was stable in both static tests and in the biological aerated filter system.

关键词： Ibuprofen Biological aerated filter Degrading bacterium Serratia marcescens

HTML PDF 收藏

真空光镊技术综述 Special Feature on Precision Measurement and Inst

Nan LI, Xun-min ZHU, Wen-qiang LI, Zhen-hai FU, Meng-zhu HU, Hui-zhu HU

《信息与电子工程前沿（英文）》 2019年第20卷第5期页码 655-673 doi: 10.1631/FITEE.1900095

摘要：光镊技术自上世纪七十年代由阿瑟·阿什金开创以来，作为捕获和操纵中性粒子的通用工具，已在分子生物学、纳米技术和实验物理学等领域得到广泛研究和应用。基于光镊技术的传感与精密测量系统，通过激光束悬浮传感单元，而非与装置固连，相比传统固态传感器，无机械耗散。此外，与液体或空气介质中的光镊系统不同，在真空中运作的光镊系统可实现传感单元与环境的完全隔离。基于上述优势，基础物理学和应用物理学领域科学家对真空光镊开展了大量研究。本文回顾了真空光镊技术的基本概念和发展历史，帮助读者全面了解该领域。

关键词：光镊；真空光阱；激光冷却

HTML PDF 收藏

Rapid transaction to load variations of active filter supplied by PV system

M. BENADJA,S. SAAD,A. BELHAMRA

《能源前沿（英文）》 2014年第8卷第3期页码 335-344 doi: 10.1007/s11708-014-0325-7

摘要： This paper deals with the analysis and control of a photovoltaic (PV) system connected to the main supply through a Boost converter and shunt active filter supplied by a PV system providing continuous supply of nonlinear load in variation. A robust control of a PV system connected to the grid while feeding a variable nonlinear load is developed and highlighted. This development is based on the control of the Boost converter to extract the maximum power from the PV system using the Perturb and Observe (P and O) algorithm in the presence of temperature and illumination. The proposed modeling and control strategy provide power to the variable nonlinear load and facilitates the transfer of power from solar panel to the grid while improving the quality of energy (harmonic currents compensation, power factor compensation and dc bus voltage regulation). Validation of the developed model and control strategy is conducted using power system simulator Sim-Power System Blockset Matlab/Simulink. To demonstrate the effectiveness of the shunt active filter to load changes, the method of instantaneous power ( theory) is used to identify harmonic currents. The obtained results show an accurate extraction of harmonic currents and perfect compensation of both reactive power and harmonic currents with a lower THD and in accordance with the IEEE-519 standard.

关键词： solar panels maximum power point tracking (MPPT) DC/DC converter (Boost) shunt active filter instantaneous power control power quality harmonics imbalances reactive energy

HTML PDF 收藏

Effect of biological activated carbon filter depth and backwashing process on transformation of biofilm

Wanqi Qi, Weiying Li, Junpeng Zhang, Xuan Wu, Jie Zhang, Wei Zhang

《环境科学与工程前沿（英文）》 2019年第13卷第1期 doi: 10.1007/s11783-019-1100-0

摘要：

We studied BAC biofilm during the process of initial operation and backwash.

Microbial diversity decreased gradually with the increase of BAC filter depth.

Proteobacteria dominated at the phylum level among the BAC biofilm samples.

α-proteobacteria increased about 10% in all carbon filter depth after backwash.

关键词： Biological activated carbon Biofilm Community structure Carbon filter depth High-throughput sequencing

HTML PDF 收藏

Ceramic water filter for point-of-use water treatment in developing countries: Principles, challenges

Haiyan Yang, Shangping Xu, Derek E. Chitwood, Yin Wang

《环境科学与工程前沿（英文）》 2020年第14卷第5期 doi: 10.1007/s11783-020-1254-9

摘要： • CWF is a sustainable POU water treatment method for developing areas. • CWF manufacturing process is critical for its filtration performance. • Simultaneous increase of flow rate and pathogen removal is a challenge. • Control of pore size distribution holds promises to improve CWF efficiency. • Novel coatings of CWFs are a promising method to improve contaminant removal. Drinking water source contamination poses a great threat to human health in developing countries. Point-of-use (POU) water treatment techniques, which improve drinking water quality at the household level, offer an affordable and convenient way to obtain safe drinking water and thus can reduce the outbreaks of waterborne diseases. Ceramic water filters (CWFs), fabricated from locally sourced materials and manufactured by local labor, are one of the most socially acceptable POU water treatment technologies because of their effectiveness, low-cost and ease of use. This review concisely summarizes the critical factors that influence the performance of CWFs, including (1) CWF manufacturing process (raw material selection, firing process, silver impregnation), and (2) source water quality. Then, an in-depth discussion is presented with emphasis on key research efforts to address two major challenges of conventional CWFs, including (1) simultaneous increase of filter flow rate and bacterial removal efficiency, and (2) removal of various concerning pollutants, such as viruses and metal(loid)s. To promote the application of CWFs, future research directions can focus on: (1) investigation of pore size distribution and pore structure to achieve higher flow rates and effective pathogen removal by elucidating pathogen transport in porous ceramic and adjusting manufacture parameters; and (2) exploration of new surface modification approaches with enhanced interaction between a variety of contaminants and ceramic surfaces.

关键词： Point-of-use water treatment Ceramic water filter Bacterial removal Surface modification Water quality