资源类型

期刊论文 311

会议视频 15

年份

2023 14

2022 15

2021 31

2020 19

2019 24

2018 11

2017 11

2016 14

2015 7

2014 24

2013 23

2012 15

2011 14

2010 25

2009 24

2008 10

2007 9

2006 3

2005 9

2004 1

展开 ︾

关键词

钢结构 10

钢箱梁 4

TRIP钢 3

三塔悬索桥 3

发展 3

可持续发展 3

低成本 2

创新 2

压力容器技术 2

双相钢 2

宝钢 2

应用 2

悬索桥 2

整体沉放 2

新技术 2

析出强化 2

泰州大桥 2

疲劳 2

碳中和 2

展开 ︾

检索范围:

排序: 展示方式:

water chemistry and ore mineralogy on the galvanic interactions between chalcopyrite and pyrite and steel

Asghar Azizi, Seid Ziaoddin Shafaei, Mohammad Noaparast, Mohammad Karamoozian

《化学科学与工程前沿(英文)》 2013年 第7卷 第4期   页码 464-471 doi: 10.1007/s11705-013-1356-z

摘要: The role of pH, solid content, water chemistry and ore mineralogy on the galvanic interactions between chalcopyrite and pyrite and low alloy steel balls were investigated in the grinding of Sarcheshmeh porphyry copper sulfide ore. All these factors strongly affect the galvanic current between the minerals and the steel during the grinding process. The galvanic current density decreased as the solution pH and percent solids increased. In addition, changing the water in the ball mill from tap to distilled water reduced the galvanic current between the minerals and the balls. Potentiodynamic polarization curves showed that pyrite and chalcopyrite demonstrated typical active-passive-transpassive anodic behavior in the grinding of copper ore. However, the nature of their transitions from the active to the passive state differed. This behavior was not seen in the grinding of pure minerals. In addition, an EDTA extraction technique was employed to quantify the amount of oxidized iron in the mill discharge. The amount of extractable iron was influenced by the same experimental factors and in the same way as the galvanic current.

关键词: steel ball     galvanic interaction     pyrite     chalcopyrite     polarization curves    

characterization of nanocrystalline ZrO2-7%Y2O3 powders for thermal barrier coatings by high-energy ball

Kirsten BOBZIN, Lidong ZHAO, Thomas SCHLAEFER, Thomas WARDA

《机械工程前沿(英文)》 2011年 第6卷 第2期   页码 176-181 doi: 10.1007/s11465-011-0220-4

摘要:

High-energy ball milling is an effective method to produce nanocrystalline oxides. In this study, a conventional ZrO2-7%Y2O3spray powder was ball-milled to produce nanocrystalline powders with high levels of crystalline disorders for deposition of thermal barrier coatings. The powder was milled both with 100Cr6 steel balls and with ZrO2-3%Y2O3 ceramic balls as grinding media. The milling time was varied in order to investigate the effect of the milling time on the crystallite size. The powders were investigated in terms of their crystallite sizes and morphologies by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that under given milling conditions the powder was already nanostructured after 40 min milling. The crystallite size decreased significantly with increasing milling time within first 120 min. After that, a further increase of milling time did not lead to a significant reduction of the crystallite size. Ball-milling led to lattice microstrains. Milling with the steel balls resulted in finer nano-sized crystal grains, but caused the contamination of the powder. The nano-sized crystal grains coarsened during the heat-treatment at 1250°C.

关键词: nanostrucured powders     yttria stabilized zirconia (YSZ)     high-energy ball milling     thermal barrier coatings    

Augmented hydrogen production by gasification of ball milled polyethylene with Ca(OH)

Giovanni Cagnetta, Kunlun Zhang, Qiwu Zhang, Jun Huang, Gang Yu

《环境科学与工程前沿(英文)》 2019年 第13卷 第1期 doi: 10.1007/s11783-019-1096-5

摘要:

PE ball milling pretreatment induces higher H2 production and purity by gasification.

Ca(OH)2 reacts at solid state with PE boosting H2 and capturing CO2.

Ca(OH)2 significantly reduces methanation side-reaction.

关键词: Hydrogen production     Gasification     Plastic waste     High energy ball milling    

Bioleaching of copper from pre and post thermally activated low grade chalcopyrite contained ball mill

Sandeep PANDA, Nilotpala PRADHAN, Umaballav MOHAPATRA, Sandeep K. PANDA, Swagat S. RATH, Danda S. RAO, Bansi D. NAYAK, Lala B. SUKLA, Barada K. MISHRA

《环境科学与工程前沿(英文)》 2013年 第7卷 第2期   页码 281-293 doi: 10.1007/s11783-013-0484-5

摘要: Bioleaching of a low grade chalcopyrite (ball mill spillage material) was tested for copper recovery in shake flasks. The original samples (as received) were thermally activated (600°C, 30 min) to notice the change in physico-chemical and mineralogical characteristics of the host rock and subsequently its effect on copper recovery. A mixed culture of acidophilic chemolithotrophic bacterial consortium predominantly entailing strain was used for bioleaching studies and optimization of process parameters of both original and thermally activated samples. Mineralogical characterization studies indicated the presence of chalcopyrite, pyrite in the silicate matrix of the granitic rock. Field emission scanning electron microscopy coupled with Energy dispersive spectroscopy (FESEM-EDS) and X-ray Fluorescence (XRF) analysis indicated mostly SiO . With pH 2, pulp density 10% w/v, inoculum 10% v/v, temperature 30°C, 150 r·min , 49% copper could be recovered in 30 days from the finest particle size (-1+ 0.75 mm) of the original spillage sample. Under similar conditions 95% copper could be recovered from the thermally activated sample with the same size fraction in 10 days. The study revealed that thermal activation leads to volume expansion in the rock with the development of cracks, micro and macro pores on its surface, thereby enabling bacterial solution to penetrate more easily into the body, facilitating enhanced copper dissolution.

关键词: ball mill spillage     thermal activation     bioleaching     copper    

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 28-36 doi: 10.1007/s11465-008-0007-4

摘要: This research focuses on the characteristics of how a ball-screw changes its temperature corresponding to the periodic change of the end-most heat source. Based on the theory of heat transfer, this paper supplies a numerical solution to the non-homogeneous equation of heat transfer through the group explicit (GE) finite difference approach. The temperature distribution for the ball-screw at different times and directions is shown. By simulating and modeling the temperature field and thermal deformation of the ball-screw under periodically varying heat sources, this paper describes the thermal dynamic characteristics of the ball-screw under such conditions. By testing the thermal dynamic characteristics of the ball-screw, the numerical solution is validated.

关键词: numerical solution     temperature corresponding     temperature distribution     end-most     ball-screw    

Effect of friction coefficients on the dynamic response of gear systems

BALL, Xuejun LI

《机械工程前沿(英文)》 2017年 第12卷 第3期   页码 397-405 doi: 10.1007/s11465-017-0415-4

摘要:

The inevitable deterioration of the lubrication conditions in a gearbox in service can change the tribological properties of the meshing teeth. In turn, such changes can significantly affect the dynamic responses and running status of gear systems. This paper investigates such an effect by utilizing virtual prototype technology to model and simulate the dynamics of a wind turbine gearbox system. The change in the lubrication conditions is modeled by the changes in the friction coefficients, thereby indicating that poor lubrication causes not only increased frictional losses but also significant changes in the dynamic responses. These results are further demonstrated by the mean and root mean square values calculated by the simulated responses under different friction coefficients. In addition, the spectrum exhibits significant changes in the first, second, and third harmonics of the meshing components. The findings and simulation method of this study provide theoretical bases for the development of accurate diagnostic techniques.

关键词: dynamic response     friction coefficient     wind loads     wind turbine gearbox    

Kinematic error separation on five-axis NC machine tool based on telescoping double ball bar

Min WANG, Jianzhong HU, Tao ZAN

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 431-437 doi: 10.1007/s11465-010-0110-1

摘要: The theory and algorithm of the homogeneous transformation matrix (HTM) method are applied in establishing the kinematic error model of five-axis machining tool with two-axis turntable. Based on this model, a new method for the kinematic error separation in five-axis numerical control (NC) machining tool is proposed. In this study, three types of simultaneous three-axis control motions are designed for each rotary axis to identify the deviations. In the measurement, two translational axes and one rotary axis are simultaneously controlled to keep a constant distance between the tool and the worktable. Telescoping double ball bar is used to measure the relative distance between the spindle and the worktable in the motion of NC machining tool. Finally, the value measured by telescoping double ball bar is substituted into the model to obtain kinematic error of NC machining tool. Comparison has confirmed that the proposed method is high precision and can be applied to effectively and conveniently measure the five-axis machining tool.

关键词: error modeling     error separation     telescoping double ball bar     five-axis numerical control (NC) machining tool    

Erratum to: One-step ball milling-prepared nano Fe

Xingguo Guo, Qiuying Wang, Ting Xu, Kajia Wei, Mengxi Yin, Peng Liang, Xia Huang, Xiaoyuan Zhang

《环境科学与工程前沿(英文)》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1258-5

Ball milling promoted direct liquefaction of lignocellulosic biomass in supercritical ethanol

Chunyan Yang, Xiaoliang Yuan, Xueting Wang, Kejing Wu, Yingying Liu, Changjun Liu, Houfang Lu, Bin Liang

《化学科学与工程前沿(英文)》 2020年 第14卷 第4期   页码 605-613 doi: 10.1007/s11705-019-1841-0

摘要: In the present work, ball milling was applied for the pretreatment of lignocellulose to obtain high conversion and bio-oil yield in supercritical ethanol. Ball milling substantially decreased the crystallinity and particle size of lignocellulose, thereby improving its accessibility in ethanol solvent. An increased bio-oil yield of 59.2% was obtained for the ball milled camphorwood sawdust at 300°C, compared with 39.6% for the original lignocellulose. Decreased crystallinity significantly benefited the conversion of the cellulose component from 60.8% to 91.7%, and decreased particle size was beneficial for the conversion of all components. The obtained bio-oil had a high phenolic content, as analyzed by gas chromatography-mass spectrometry. Methoxylation and retro-aldol condensation were observed during alcoholysis, and the reaction pathways of lignocellulose in supercritical ethanol were attributed to the action of free radicals.

关键词: ball milling     lignocellulose     supercritical ethanol     liquefaction     bio-oil    

One-step ball milling-prepared nano Fe

Xingguo Guo, Qiuying Wang, Ting Xu, Kajia Wei, Mengxi Yin, Peng Liang, Xia Huang, Xiaoyuan Zhang

《环境科学与工程前沿(英文)》 2020年 第14卷 第2期 doi: 10.1007/s11783-019-1209-1

摘要: • Nano Fe2O3 and N-doped graphene was prepared via a one-step ball milling method. • The maximum power density of Fe-N-G in MFC was 390% of that of pristine graphite. • Active sites like nano Fe2O3, pyridinic N and Fe-N groups were formed in Fe-N-G. • The improvement of Fe-N-G was due to full exposure of active sites on graphene. Developing high activity, low-cost and long durability catalysts for oxygen reduction reaction is of great significance for the practical application of microbial fuel cells. The full exposure of active sites in catalysts can enhance catalytic activity dramatically. Here, novel Fe-N-doped graphene is successfully synthesized via a one-step in situ ball milling method. Pristine graphite, ball milling graphene, N-doped graphene and Fe-N-doped graphene are applied in air cathodes, and enhanced performance is observed in microbial fuel cells with graphene-based catalysts. Particularly, Fe-N-doped graphene achieves the highest oxygen reduction reaction activity, with a maximum power density of 1380±20 mW/m2 in microbial fuel cells and a current density of 23.8 A/m2 at –0.16 V in electrochemical tests, which are comparable to commercial Pt and 390% and 640% of those of pristine graphite. An investigation of the material characteristics reveals that the superior performance of Fe-N-doped graphene results from the full exposure of Fe2O3 nanoparticles, pyrrolic N, pyridinic N and excellent Fe-N-G active sites on the graphene matrix. This work not only suggests the strategy of maximally exposing active sites to optimize the potential of catalysts but also provides promising catalysts for the use of microbial fuel cells in sustainable energy generation.

关键词: Microbial fuel cells     Air cathodes     Nano Fe2O3 and nitrogen-doped graphene     Oxygen reduction reaction    

动态变化滚珠丝杠进给系统的智能非同位控制策略

刘辉, 张俊, 赵万华

《工程(英文)》 2017年 第3卷 第5期   页码 641-647 doi: 10.1016/J.ENG.2017.04.007

摘要:
滚珠丝杠进给驱动系统由于其细长的螺旋主轴和部件之间连接部分的灵活性,具有变化的高阶动态特性,并且当采用直线光栅尺进行直接位置测量时,它还具有非同位控制的明显特征。长期以来,动态特性和非同位状况一直是运动和振动控制困难的根源,它们还会降低轴的运动精度。在本研究中,考虑到灵活性及其变化,我们建立了基于频率的子结构动态模型,并充分研究了动态特性对位置变化的依赖,开发出由模态特征修正器(MCM)和智能自适应调整算法(ATA)组成的控制策略。MCM 由峰值滤波器和陷波滤波器组成,从而将设备动态变为虚拟同位系统,且可以避免控制溢出。使用人工神经网络(ANN)作为平滑参数插值器,可以实时更新滤波器的参数,以便应对进给驱动系统的动态变化。我们已经在实际的进给驱动系统中验证了所提出策略的有效性和鲁棒性。

关键词: 滚珠丝杠进给驱动系统     变化高阶动态     非同位控制     模态特征修正器     智能自适应调整算法    

中国钢桥

潘际炎

《中国工程科学》 2007年 第9卷 第7期   页码 18-26

摘要:

介绍了我国钢桥的发展及国内外的钢桥比较;论述了建造钢桥的钢材及其要求的化学成分和物理力学性能。

关键词: 中国钢桥     钢材     钢桥设计     钢桥结构    

On braced trapezoidal corrugated steel shear panels: An experimental and numerical study

《结构与土木工程前沿(英文)》 2023年 第17卷 第3期   页码 396-410 doi: 10.1007/s11709-023-0934-5

摘要: In this study, a new system consisting of a combination of braces and steel infill panels called the braced corrugated steel shear panel (BCSSP) is presented. To obtain the hysteretic behavior of the proposed system, the quasi-static cyclic performances of two experimental specimens were first evaluated. The finite element modeling method was then verified based on the obtained experimental results. Additional numerical evaluations were carried out to investigate the effects of different parameters on the system. Subsequently, a relationship was established to estimate the buckling shear strength of the system without considering residual stresses. The results obtained from the parametric study indicate that the corrugated steel shear panel (CSSP) with the specifications of a = 30 mm, t = 2 mm, and θ = 90° had the highest energy dissipation capacity and ultimate strength while the CSSP with the specifications of a = 30 mm, t = 2 mm, and θ = 30° had the highest initial stiffness. It can thus be concluded that the latter CSSP has the best structural performance and that increasing the number of corrugations, corrugation angle, and plate thickness and decreasing the sub-panel width generally enhance the performance of CSSPs in terms of the stability of their hysteretic behaviors.

关键词: trapezoidal corrugated plate     steel shear panel     braced steel shear panel     experimental study     buckling resistance.    

Events and reaction mechanisms during the synthesis of an Al

M. ABDELLAHI, M. ZAKERI, H. BAHMANPOUR

《化学科学与工程前沿(英文)》 2013年 第7卷 第2期   页码 123-129 doi: 10.1007/s11705-013-1325-6

摘要: An Al O -TiB nanocomposite was successfully synthesized by the high energy ball milling of Al, B O and TiO . The structures of the powdered particles formed at different milling times were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Thermodynamic calculations showed that the composite formed in two steps via highly exothermic mechanically induced self-sustaining reactions (MSRs). The composite started to form at milling times of 9–10 h but the reaction was not complete. The remaining starting materials were consumed by increasing the milling time to 15 h. The XRD patterns of the annealed powders showed that aluminum borate is one of the intermediate products and that it is consumed at higher temperatures. Heat treatment of the 6-h milled sample at 1100 C led to a complete formation of the composite. Increasing the milling time to 15 h led to a refining of the crystallite sizes. A nanocomposite powder with a mean crystallite size of 35–40 nm was obtained after milling for 15 h.

关键词: ball milling     nanocomposite     Al2O3     TiB2    

宝钢纯净钢生产技术的进步

崔健,郑贻裕,朱立新

《中国工程科学》 2005年 第7卷 第6期   页码 21-26

摘要:

论述了钢中碳、氮、氧、磷、硫以及夹杂物控制方面的技术进步,讨论了IF钢、管线钢所达到的纯净度纵使水平。

关键词: 宝钢     纯净钢     IF钢     管线钢     炼钢    

标题 作者 时间 类型 操作

water chemistry and ore mineralogy on the galvanic interactions between chalcopyrite and pyrite and steel

Asghar Azizi, Seid Ziaoddin Shafaei, Mohammad Noaparast, Mohammad Karamoozian

期刊论文

characterization of nanocrystalline ZrO2-7%Y2O3 powders for thermal barrier coatings by high-energy ball

Kirsten BOBZIN, Lidong ZHAO, Thomas SCHLAEFER, Thomas WARDA

期刊论文

Augmented hydrogen production by gasification of ball milled polyethylene with Ca(OH)

Giovanni Cagnetta, Kunlun Zhang, Qiwu Zhang, Jun Huang, Gang Yu

期刊论文

Bioleaching of copper from pre and post thermally activated low grade chalcopyrite contained ball mill

Sandeep PANDA, Nilotpala PRADHAN, Umaballav MOHAPATRA, Sandeep K. PANDA, Swagat S. RATH, Danda S. RAO, Bansi D. NAYAK, Lala B. SUKLA, Barada K. MISHRA

期刊论文

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

期刊论文

Effect of friction coefficients on the dynamic response of gear systems

BALL, Xuejun LI

期刊论文

Kinematic error separation on five-axis NC machine tool based on telescoping double ball bar

Min WANG, Jianzhong HU, Tao ZAN

期刊论文

Erratum to: One-step ball milling-prepared nano Fe

Xingguo Guo, Qiuying Wang, Ting Xu, Kajia Wei, Mengxi Yin, Peng Liang, Xia Huang, Xiaoyuan Zhang

期刊论文

Ball milling promoted direct liquefaction of lignocellulosic biomass in supercritical ethanol

Chunyan Yang, Xiaoliang Yuan, Xueting Wang, Kejing Wu, Yingying Liu, Changjun Liu, Houfang Lu, Bin Liang

期刊论文

One-step ball milling-prepared nano Fe

Xingguo Guo, Qiuying Wang, Ting Xu, Kajia Wei, Mengxi Yin, Peng Liang, Xia Huang, Xiaoyuan Zhang

期刊论文

动态变化滚珠丝杠进给系统的智能非同位控制策略

刘辉, 张俊, 赵万华

期刊论文

中国钢桥

潘际炎

期刊论文

On braced trapezoidal corrugated steel shear panels: An experimental and numerical study

期刊论文

Events and reaction mechanisms during the synthesis of an Al

M. ABDELLAHI, M. ZAKERI, H. BAHMANPOUR

期刊论文

宝钢纯净钢生产技术的进步

崔健,郑贻裕,朱立新

期刊论文