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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    

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Mechanical properties and microstructure of multilayer graphene oxide cement mortar

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 1058-1070 doi: 10.1007/s11709-021-0747-3

摘要： This study reports on the effects of multilayer graphene oxide (MGO) on compressive strength, flexural strength, and microstructure of cement mortar. The cement mortar was prepared with type P. II. 52.5 Portland cement, standard sand, and MGO. Four mixes were prepared with inclusion of MGO (0%, 0.02%, 0.04%, and 0.06% by weight of cement). The testing result shows that the compressive of GO-cement mortar increased by 4.84%–13.42%, and the flexural strength increased by 4.37%–8.28% at 3 d. GO-cement mortar’s compressive strength and flexural strength at 7 d increased by 3.84%–12.08% and 2.54%–13.43%, respectively. MGO made little contribution to the increases of compressive strength and flexural strength of cement mortar at 28 d. The results of X-ray diffraction (XRD), scanning electron microscope (SEM), and nitrogen (N2) adsorption/desorption tests show that the types of hydration products and crystal grain size did not change after adding MGO. Still, it can help to improve the microstructure of the cement mortar via regulating hydration products and can provide more condensed cores to accelerate hydration. Furthermore, the regulating action of MGO for the microstructure of cement mortar at an early age was better than that at 28 d.

关键词： graphene oxide     cement     mortar     mechanical properties     microstructure    

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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    

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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    

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Hydration, microstructure and autogenous shrinkage behaviors of cement mortars by addition of superabsorbent

Beibei SUN, Hao WU, Weimin SONG, Zhe LI, Jia YU

《结构与土木工程前沿（英文）》 2020年 第14卷 第5期   页码 1274-1284 doi: 10.1007/s11709-020-0656-x

摘要： Superabsorbent Polymer (SAP) has emerged as a topic of considerable interest in recent years. The present study systematically and quantitively investigated the effect of SAP on hydration, autogenous shrinkage, mechanical properties, and microstructure of cement mortars. Influences of SAP on hydration heat and autogenous shrinkage were studied by utilizing TAM AIR technology and a non-contact autogenous shrinkage test method. Scanning Electron Microscope (SEM) was employed to assess the microstructure evolution. Although SAP decreased the peak rate of hydration heat and retarded the hydration, it significantly increased the cumulative heat, indicating SAP helps promote the hydration. Hydration promotion caused by SAP mainly occurred in the deceleration period and attenuation period. SAP can significantly mitigate the autogenous shrinkage when the content ranged from 0 to 0.5%. Microstructure characteristics showed that pores and gaps were introduced when SAP was added. The microstructure difference caused by SAP contributed to the inferior mechanical behaviors of cement mortars treated by SAP.

关键词： Superabsorbent Polymer     mechanical properties     hydration heat     autogenous shrinkage     microstructure    

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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    

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Effects of fiber curvature on the microstructure of the interfacial transition zone in fresh concrete

CHEN Huisu, SUN Wei, ZHAO Qingxin, L. J. Sluys, P. Stroeven

《结构与土木工程前沿（英文）》 2007年 第1卷 第1期   页码 99-106 doi: 10.1007/s11709-007-0010-6

摘要： The study on the interfacial transition zone (ITZ) of concrete has received lots of attention in the last decade. However, no information is available on the influence of the curvature of a rigid surface on the microstructure of ITZ. This paper employed computer simulation technology to study the influence of fiber curvature on the initial microstructure of ITZ in concrete. For the sake of simplification, the investigation was first focused on the mono-size spherical particle packing system around a cylindrical fiber with different diameters. An algorithm of serial cylindrical sectioning was developed. The curve of the solid volume fraction versus the distance to the surface of the fiber was used as a parameter to characterize the microstructure of the ITZ. Then, the influence of the ratio of fiber diameter to particle diameter on the initial ITZ s microstructure was studied. These curves were compared with the ones from flat aggregate surface on which mono-size spherical particles were packed. Furthermore, the multi-size spherical particles system was further investigated. The simulation results demonstrate that no matter whether the spherical particles system is mono-size or multi-size, the fresh ITZ s microstructure is irrelevant to the curvature of the fiber. The shape of the curve of solid volume fraction versus the distance from the surface of the fiber is similar to that around a flat aggregate surface. In all cases, the horizontal coordinates of the first peak of the curves are located at around half the mean weight diameter of the particles. The thickness of ITZ reduces slightly with the decrease in water/cement ratio. Therefore, one may use the ITZ s microstructure around a flat aggregate surface to represent the ITZ s microstructure around a cylindrical fiber in the fresh state, and vice versa.

关键词： diameter     initial microstructure     influence     surface     spherical particle    

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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    

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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    

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Compressive behavior and microstructure of concrete mixed with natural seawater and sea sand

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1347-1357 doi: 10.1007/s11709-021-0780-2

摘要： Noncorrosive reinforcement materials facilitate producing structural concrete with seawater and sea sand. This study investigated the properties of seawater and sea sand concrete (SSC), considering the curing age (3, 7, 14, 21, 28, 60, and 150 d) and strength grade (C30, C40, and C60). The compressive behavior of SSC was obtained by compressive tests and digital image correction (DIC) technique. Scanning electron microscope (SEM) and X-ray powder diffraction (XRD) methods were applied to understand the microstructure and hydration products of cement in SSC. Results revealed a 30% decrease in compressive strength for C30 and C40 SSC from 60 to 150 d, and a less than 5% decrease for C60 from 28 to 150 d. DIC results revealed significant cracking and crushing from 80% to 100% of compressive strength. SEM images showed a more compact microstructure in higher strength SSC. XRD patterns identified Friedel’s salt phase due to the chlorides brought by seawater and sea sand. The findings in this study can provide more insights into the microstructure of SSC along with its short- and long-term compressive behavior.

关键词： seawater and sea sand concrete     compressive strength     strain field     microstructure     hydration products    

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Effects of natural zeolite and sulfate ions on the mechanical properties and microstructure of plastic

《结构与土木工程前沿（英文）》 2022年 第16卷 第1期   页码 86-98 doi: 10.1007/s11709-021-0793-x

摘要： One of the strategic materials used in earth-fill embankment dams and in modifying and preventing groundwater flow is plastic concrete (PlC). PlC is comprised of aggregates, water, cement, and bentonite. Natural zeolite (NZ) is a relatively abundant mineral resource and in this research, the microstructure, unconfined strength, triaxial behavior, and permeability of PlC made with 0%, 10%, 15%, 20%, and 25% replacement of cement by NZ were studied. Specimens of PIC-NZ were subjected to confined conditions and three different confining pressures of 200, 350, and 500 kPa were used to investigate their mechanical behavior and permeability. To study the effect of sulfate ions on the properties of PlC-NZ specimens, the specimens were cured in one of two different environments: normal condition and in the presence of sulfate ions. Results showed that increasing the zeolite content decreases the unconfined strength, elastic modulus, and peak strength of PlC-NZ specimens at the early ages of curing. However, at the later ages, increasing the zeolite content increases unconfined strength as well as the peak strength and elastic modulus. Specimens cured in the presence of sulfate ions indicated lower permeability, higher unconfined strength, elastic modulus, and peak strength due to having lower porosity.

关键词： plastic concrete     sulfate resistance     natural zeolite     triaxial compression test     SEM     permeability    

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Differences in microstructure and properties between selective laser melting and traditional manufacturing

Bo SONG,Xiao ZHAO,Shuai LI,Changjun HAN,Qingsong WEI,Shifeng WEN,Jie LIU,Yusheng SHI

《机械工程前沿（英文）》 2015年 第10卷 第2期   页码 111-125 doi: 10.1007/s11465-015-0341-2

摘要：

Selective laser melting (SLM), as one of the additive manufacturing technologies, is widely investigated to fabricate metal parts. In SLM, parts are manufactured directly from powders in a layer-by-layer fashion; SLM also provides several advantages, such as production of complex parts with high three-dimensional accuracy, compared with other additive manufacturing technologies. Therefore, SLM can be applied in aeronautics, astronautics, medicine, and die and mould industry. However, this technique differs from traditional methods, such as casting and forging; for instance, the former greatly differs in terms of microstructure and properties of products. This paper summarizes relevant studies on metal material fabrication through SLM. Based on a work completed in Huazhong Univ. Sci Tech., Rapid Manuf. Center (HUST-RMC) and compared with characteristics described in other reported studies, microstructure, properties, dimensional accuracy, and application of SLM are presented.

关键词： selective laser melting     microstructure     performance     application    

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Correlation of chloride diffusion coefficient and microstructure parameters in concrete: A comparative

Yurong ZHANG, Shengxuan XU, Yanhong GAO, Jie GUO, Yinghui CAO, Junzhi ZHANG

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1509-1519 doi: 10.1007/s11709-020-0681-9

摘要： Permeability is a major indicator of concrete durability, and depends primarily on the microstructure characteristics of concrete, including its porosity and pore size distribution. In this study, a variety of concrete samples were prepared to investigate their microstructure characteristics via nuclear magnetic resonance (NMR), mercury intrusion porosimetry (MIP), and X-ray computed tomography (X-CT). Furthermore, the chloride diffusion coefficient of concrete was measured to explore its correlation with the microstructure of the concrete samples. Results show that the proportion of pores with diameters<1000 nm obtained by NMR exceeds that obtained by MIP, although the difference in the total porosity determined by both methods is minimal. X-CT measurements obtained a relatively small porosity; however, this likely reflects the distribution of large pores more accurately. A strong correlation is observed between the chloride diffusion coefficient and the porosity or contributive porosity of pores with sizes<1000 nm. Moreover, microstructure parameters measured via NMR reveal a lower correlation coefficient versus the chloride diffusion coefficient relative to the parameters determined via MIP, as NMR can measure non-connected as well as connected pores. In addition, when analyzing pores with sizes>50 µm, X-CT obtains the maximal contributive porosity, followed by MIP and NMR.

关键词： permeability     microstructure     NMR     MIP     X-CT    

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Calculating frictional force with considering material microstructure and potential on contact surfaces

XU Zhongming, HUANG Ping

《机械工程前沿（英文）》 2007年 第2卷 第4期   页码 474-477 doi: 10.1007/s11465-007-0082-y

摘要： A method based on the energy dissipation mechanism of an Independent Oscillator model is used to calculate the frictional force and the friction coefficient of interfacial friction. The friction work is calculated with considering the potential change of contact surfaces during sliding. The potential change can be gained by a universal adhesive energy function. The relationships between frictional force and parameters of a tribo-system, such as surface energy and microstructure of interfacial material, are set up. The calculation results of the known experimental data denote that the frictional force is nearly proportional to the surface energy of the material, nearly inversely proportional to the scaling length, and independent of the lattice constant. The results agree with that of adhesion friction equations. They also agree with the experimental results performed with an atomic-force microscope under the ultra high vacuum condition.

关键词： coefficient     dissipation mechanism     universal adhesive     interfacial     Independent Oscillator    

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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    

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标题 作者 时间 类型 操作

Recent advancements in optical microstructure fabrication through glass molding process

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

期刊论文

Mechanical properties and microstructure of multilayer graphene oxide cement mortar

期刊论文

Development of surface reconstruction algorithms for optical interferometric measurement

Dongxu WU, Fengzhou FANG

期刊论文

Precision glass molding: Toward an optimal fabrication of optical lenses

Liangchi ZHANG,Weidong LIU

期刊论文

Hydration, microstructure and autogenous shrinkage behaviors of cement mortars by addition of superabsorbent

Beibei SUN, Hao WU, Weimin SONG, Zhe LI, Jia YU

期刊论文

国外光纤光纤带和带状光缆技术的最新发展

刘良炎

期刊论文

Effects of fiber curvature on the microstructure of the interfacial transition zone in fresh concrete

CHEN Huisu, SUN Wei, ZHAO Qingxin, L. J. Sluys, P. Stroeven

期刊论文

成像光学工程面临的光学问题

潘君骅

期刊论文

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

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

期刊论文

Compressive behavior and microstructure of concrete mixed with natural seawater and sea sand

期刊论文

Effects of natural zeolite and sulfate ions on the mechanical properties and microstructure of plastic

期刊论文

Differences in microstructure and properties between selective laser melting and traditional manufacturing

Bo SONG,Xiao ZHAO,Shuai LI,Changjun HAN,Qingsong WEI,Shifeng WEN,Jie LIU,Yusheng SHI

期刊论文

Correlation of chloride diffusion coefficient and microstructure parameters in concrete: A comparative

Yurong ZHANG, Shengxuan XU, Yanhong GAO, Jie GUO, Yinghui CAO, Junzhi ZHANG

期刊论文

Calculating frictional force with considering material microstructure and potential on contact surfaces

XU Zhongming, HUANG Ping

期刊论文

真空光镊技术综述

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

期刊论文