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高速高冲击性小型增量式光电编码器的研制 被引量:9
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作者 陈赟 李秀茹 +1 位作者 张红胜 李艳茹 《电子测量与仪器学报》 CSCD 2013年第10期916-921,共6页
光电编码器作为一种角位移测量传感器广泛应用于多个领域中,根据光栅盘的编码方式主要分为绝对式和增量式2种。绝对式光电编码器多用于角度测量,增量式光电编码器多用作速度测量,由于器件的限制,高速、高冲击是增量式光电编码器的1个瓶... 光电编码器作为一种角位移测量传感器广泛应用于多个领域中,根据光栅盘的编码方式主要分为绝对式和增量式2种。绝对式光电编码器多用于角度测量,增量式光电编码器多用作速度测量,由于器件的限制,高速、高冲击是增量式光电编码器的1个瓶颈。结合材料的高低温性能和强度特性,采用CPLD硬件细分,设计了1种增量式光电编码器,该种光电编码器具有高速(转速为3 000 r/min)、高冲击性(峰值500 g)、超小型(外径为Φ27 mm,高度为15 mm)和较好的高低温(-40^+70℃)性能等优点。 展开更多
关键词 光电编码器 绝对式 增量式 高冲击性
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食用香精中的高冲击性香料 被引量:2
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作者 沈演炯 徐毓莉 《香料香精化妆品》 CAS 2003年第1期32-33,共2页
关键词 食用香精 高冲击性香料 香气阈值 特征香气 香料
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高冲击性香料在食品香精中的应用 被引量:1
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作者 安淑英 《食品安全导刊》 2017年第06X期126-127,共2页
调香师在研究食品香精的香气时,通常会用到一些香气极强、香气特征明显、在配方中用量很少、气质联用仪(GC-MS)也很难分析到的香料,我们称这些香料为高冲击性香料。高冲击性香料的巧妙应用,可以提高食品香精的像真度和自然的香气,提高... 调香师在研究食品香精的香气时,通常会用到一些香气极强、香气特征明显、在配方中用量很少、气质联用仪(GC-MS)也很难分析到的香料,我们称这些香料为高冲击性香料。高冲击性香料的巧妙应用,可以提高食品香精的像真度和自然的香气,提高食品香精的市场竞争力。同时,对研究食品香精也是一种技术的进步。因此,本文主要探讨高冲击性香料在食品香精中的应用,以供参考。 展开更多
关键词 高冲击性香料 食品香精 阈值
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Microstructural evolution and mechanical properties of duplex-phase Ti6242 alloy treated by laser shock peening
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作者 Pu-ying SHI Xiang-hong LIU +3 位作者 Yong REN Zeng TIAN Feng-shou ZHANG Wei-feng HE 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第8期2521-2532,共12页
The effects of laser shock peening(LSP)on the microstructural evolution and mechanical properties of the Ti6242 alloy,including the residual stress,surface roughness,Vickers microhardness,tensile mechanical response,a... The effects of laser shock peening(LSP)on the microstructural evolution and mechanical properties of the Ti6242 alloy,including the residual stress,surface roughness,Vickers microhardness,tensile mechanical response,and high-cycle fatigue properties,were studied.The results showed that the LSP induced residual compressive stresses on the surface and near surface of the material.The maximum surface residual compressive stress was−661 MPa,and the compressive-stress-affected depth was greater than 1000μm.The roughness and Vickers micro-hardness increased with the number of shocks,and the maximum hardness-affected depth was about 700μm after three LSP treatments.LSP enhanced the fraction of low-angle grain boundaries,changed the grain preferred orientations,and notably increased the pole density ofαphase on the near surface from 2.41 to 3.46.The surface hardness values of the LSP samples increased with the increase of the number of shocks due to work hardening,while the LSP had a limited effect on the tensile properties.The high-cycle fatigue life of the LSP-treated sample was significantly enhanced by more than 20%compared with that of the untreated sample,which was caused by the suppression of the initiation and propagation of fatigue cracks. 展开更多
关键词 duplex-phase Ti6242 alloy surface modification laser shock peening gradient microstructure high-cycle fatigue properties
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Effect of Sb on microstructure and mechanical properties in Mg-10Zn-5Al high zinc magnesium alloys 被引量:4
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作者 张金山 张照光 +2 位作者 张玉华 李山虎 刘雅丽 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第3期377-382,共6页
In view of high strength and poor impact toughness of the high-zinc magnesium alloys,the method of micro-alloying was adopted to improve the impact-toughness of Mg-10Zn-5Al high zinc magnesium alloys by adjusting the ... In view of high strength and poor impact toughness of the high-zinc magnesium alloys,the method of micro-alloying was adopted to improve the impact-toughness of Mg-10Zn-5Al high zinc magnesium alloys by adjusting the addition of Sb.The results show that:the dystectic Mg3Sb2 particles formed by Sb and Mg are distributed in the front of dendrite,restrain the growth of the secondary phase and then change the morphology of the secondary phases,which refines the matrix in some extent and improves the impact-toughness of the alloy significantly.But with further increase of Sb addition,Mg3Sb2 particles congregate and form needle-like Mg3Sb2 phase,which dissevers the matrix and leads to the reduction of the strength and impact-toughness of the alloys.Hence,the mechanical prosperities of ZA105 high zinc magnesium alloy are significantly improved with appropriate Sb addition,which provides a new way to extend the application fields of high zinc magnesium alloy. 展开更多
关键词 ZA105 high-zinc magnesium alloy mechanical properties secondary phase
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Combined effect of steel fibres and steel rebars on impact resistance of high performance concrete 被引量:9
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作者 陈相宇 丁一宁 C.Azevedo 《Journal of Central South University》 SCIE EI CAS 2011年第5期1677-1684,共8页
The impact properties of normal concrete (NC) and reinforced concrete (RC) specimens,steel fibre reinforced concrete (SFRC) specimens and RC+SFRC specimens with different steel fibre dosages were investigated with the... The impact properties of normal concrete (NC) and reinforced concrete (RC) specimens,steel fibre reinforced concrete (SFRC) specimens and RC+SFRC specimens with different steel fibre dosages were investigated with the drop-weight impact test recommended by ACI Committee 544.The results indicate that the number of blows to final failure is greatly increased by addition of steel fibres.Moreover,the combination of steel fibres and steel rebars demonstrates a significant positive composite effect on the impact resistance,which results in the improvement in impact toughness of concrete specimens.In the view of variation of impact test results,the two-parameter Weibull distribution was adopted to analyze the experimental data.It is proved that the probabilistic distributions of the blows to first crack and to final failure of six types of samples approximately follow two-parameter Weibull distribution. 展开更多
关键词 impact resistance high performance concrete FIBRE Weibull distribution
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Impingement capability of high-pressure submerged water jet: Numerical prediction and experimental verification 被引量:3
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作者 刘海霞 邵启明 +1 位作者 康灿 龚辰 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第10期3712-3721,共10页
At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet veloci... At jet pressures ranging from 80 to 120 MPa, submerged water jets are investigated by numerical simulation and experiment. Numerical simulation enables a systematic analysis of major flow parameters such as jet velocity, turbulent kinetic energy as well as void fraction of cavitation. Experiments facilitate an objective assessment of surface morphology, micro hardness and surface roughness of the impinged samples. A comparison is implemented between submerged and non-submerged water jets. The results show that submerged water jet is characterized by low velocity magnitudes relative to non-submerged water jet at the same jet pressure. Shear effect serves as a key factor underlying the inception of cavitation in submerged water jet stream. Predicted annular shape of cavity zone is substantiated by local height distributions associated with experimentally obtained footprints. As jet pressure increases, joint contribution of jet kinetic energy and cavitation is demonstrated. While for non-submerged water jet, impingement force stems exclusively from flow velocity. 展开更多
关键词 submerged water jet CAVITATION shear effect impingement test micro hardness surface morphology
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An Enhanced Physically Based Scour Model for Considering Jet Air Entrainment 被引量:2
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作者 Rafael Duarte Antonio Pinheiro Anton J. Schleiss 《Engineering》 SCIE EI 2016年第3期294-301,共8页
Based on systematic experiments on the influence of air entrainment on rock block stability in plunge pools impacted by high-velocity jets,this study presents adaptations of a physically based scour model.The modifica... Based on systematic experiments on the influence of air entrainment on rock block stability in plunge pools impacted by high-velocity jets,this study presents adaptations of a physically based scour model.The modifications regarding jet aeration are implemented in the Comprehensive Scour Model(CSM),allowing it to reproduce the physical-mechanical processes involved in scour formation concerning the three phases;namely,water,rock,and air.The enhanced method considers the reduction of momentum of an aerated jet as well as the decrease of energy dissipation in the jet diffusive shear layer,both resulting from the entrainment of air bubbles.Block ejection from the rock mass depends on a combination of the aerated time-averaged pressure coefficient and the modified maximum dynamic impulsion coefficient,which was found to be a constant value of 0.2 for high-velocity jets in deep pools.The modified model is applied to the case of the observed scour hole at the Kariba Dam,with good agreement. 展开更多
关键词 Air entrainmentUpliftRock scourDam safetyHigh-velocity jetsBlock stabilityScour assessment
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From Inert Knowledge to Activated Knowledge: Practical Ideas for Improving Student Learning
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作者 Enoch Hale 《Journal of Philosophy Study》 2013年第4期312-323,共12页
In this article, I argue for the integration of learner-centered, high impact practices for the typical day of instruction. In doing so, I build off of a general, but robust, theoretical framework designed to promote ... In this article, I argue for the integration of learner-centered, high impact practices for the typical day of instruction. In doing so, I build off of a general, but robust, theoretical framework designed to promote substantive self-reflection which orients the tactical suggestions for improving student learning. The recommendations are practical and easily adopted as resources for challenging students to develop general critical thinking skills and dispositions especially those addressing metacognition and questioning one's assumptions of knowledge and understanding. 展开更多
关键词 best teaching practices high impact strategies critical thinking KNOWLEDGE inert knowledge
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Hopkinson Tensile Tests of Flat Specimens
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作者 Ivo Dohnal, Miroslav Slais Milan Forejt Libor Mrna 《Journal of Mechanics Engineering and Automation》 2013年第9期560-565,共6页
The SHTBT (split Hopkinson tensile bar test) is used for the determination of mechanical material properties at high strain rates, in this case within 10^2-10^3 s^-1. The duration of impact loading is within the ran... The SHTBT (split Hopkinson tensile bar test) is used for the determination of mechanical material properties at high strain rates, in this case within 10^2-10^3 s^-1. The duration of impact loading is within the range of 40-100 μS. The principle of SHTBT is based on the measurement and evaluation of impact loading that is common in high strain rate processes. Strain gauges are usually used to record impact loading. In this case, cylindrical capacitance detectors were used. Plastic deformation of metallic materials and alloys is a complex process that depends on a number of factors with the effect of strain rate being of particular importance. Dynamical tests are used for determination of mechanical properties; therefore, SHTBT is often used for these experiments. The present paper deals with possibilities of testing device for flat bars adapted at Hopkinson test. The aim of this work is concentrated on strain rate influence on 1.4301 austenitic steel, too. 展开更多
关键词 Flat specimen STRESS-STRAIN strain rate SHTBT.
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Shock relations in gases of heterogeneous thermodynamic properties
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作者 HU ZongMin ZHOU Kai +2 位作者 PENG Jun LI JinPing JIANG ZongLin 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第7期1050-1057,共8页
Shock relations usually found in literatures are derived theoretically under the assumption of homogeneous thermodynamic properties, i.e., constant ratio of specific heats, γ. However, high temperature effects post a... Shock relations usually found in literatures are derived theoretically under the assumption of homogeneous thermodynamic properties, i.e., constant ratio of specific heats, γ. However, high temperature effects post a strong shock wave may result in thermodynamic heterogeneities and failure to the original shock relations. In this paper, the shock relations are extended to take account of high-temperature effects. Comparison indicates that the present approach is more feasible than other analytical approaches to reflect the influence of γ heterogeneity on the post-shock parameters. 展开更多
关键词 shock wave imperfect gas heterogeneous theoretical solution
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