薄壁零件高速铣削动态切削力

通过微元铣削力与瞬时未变形切屑厚度之间的线性关系,提出了螺旋圆柱铣刀的瞬时切削力模型。在此基础上,采用两自由度弹性-阻尼系统,建立了适合薄壁零件的综合考虑刀具子系统和工件子系统动态特性的动态铣削力模型。最后通过实际测量数据与模型计算数据的对比,验证了提出的动态铣削力模型的有效性。

力动态视角下汉语致役类动结式的语义建构及认知理据

汉语致役类动结式具有语力动态性,其结构简练而寓意丰富。从Talmy的力动态模型和认知转喻视角考察汉语致役类动结式的语义建构及认知理据,研究发现:(1)致役类动结式致事力量可源于恒力、力量转换和外力;(2)致役类动结式可分为恒力致役类动结式、力量转换致役类动结式以及外力致役类动结式;(3)致役类动结式“力量来源”的语义建构与动结式底层论元之间的指称关系紧密;(4)致役类动结式多样“力量来源”的理据是认知转喻,即在事件理想认知模型中,致役类动结式“使因事件”中的“致事”或“役事”代替整个事件,实现部分代整体的认知转喻路径。

电动注塑机用滚珠丝杠副的动态应力分析

通过建立电动注塑机用滚珠丝杠副接触角等结构参数以及速度和加速度的动态受力模型,利用螺母和丝杠的速度关系,得到二者之间加速度的关系。应用赫兹应力公式推导出螺母侧和丝杠侧的接触应力公式,并进一步分析了接触角等结构参数以及速度和加速度对丝杠副接触应力的影响。结果表明,对于电动注塑机用滚珠丝杠副,速度的增大会造成接触应力的明显增加,加速度的增加也会造成接触应力的增加。

特种减摇装置的升力模型优化

减摇鳍是一种特种减摇装置,它在船舶减摇装置中占有重要地位,本文首先对低航速减摇鳍在水中运动所受的作用力进行分析。其次,利用计算流体力学仿真软件Fluent对减摇鳍在低航速状况下进行仿真分析,并利用Matlab拟合出低航速减摇鳍的动态升力模型。最后,对拟合出的动态升力公式进行验证。结果分析表明:拟合出的动态升力公式可以很好的反应减摇鳍在低航速海况下进行主动拍击过程所产生的升力,可以为舰船在低航速海况下设计减摇控制系统提供一定的参考。

力动态理论视角下儿童言语行为语力的个案研究

学龄前儿童言语的社会互动性较弱,具有以自我为中心的特点,但这并不意味着儿童言语行为不具有语力。相反,在对话互动过程中,儿童能够通过话语向听话人(家长、老师、同伴等)施加力的作用,促使听话人的状态发生变化。本文基于Leonard Talmy (2000)的力动态理论,对一名4岁5月龄的汉语儿童的言语行为语力进行个案研究,以阐释对话中话论转换时儿童言语行为的语力动态变化过程。本研究发现,儿童的言语行为主要包括阻止式、否认式、称赞式、指令式、协商式和陈述式,并有相应的语力标记。本文通过语力–动态模型分析儿童言语行为的语力,较为直观地展现了儿童言语行为在交际中的作用过程,有助于增进我们对儿童语言能力发展和语言习得过程的认识,从而为认知语用学研究提供一定的研究启示。

R铣刀加工高温合金GH706动态铣削力建模

采用机械力学模型,在综合考虑前刀面剪切效应和后刀面犁切效应的基础上建立了R铣刀动态铣削力模型。通过高温合金GH706的铣削力实验,对动态铣削力系数进行标定。利用Matlab科学计算软件对一个铣削周期内的铣削力进行数值仿真,计算与实验结果对比表明,模型有效、预测精确。R铣刀动态铣削力的研究,为高温合金GH706切削稳定性领域的研究奠定了理论基础。

亲子关系和家庭学习环境对初中生复原力的影响研究

复原力是个体面对压力困境时恢复的能力,提高初中生的复原力水平有利于学生从困境和挫折中更快地恢复,且能有益于改善其学业成绩,提高心理健康水平,实现个人的可持续发展。运用2016年对中国广西、贵州、辽宁、云南和重庆五个省区市7个县的1763名初中生调查数据,了解当前初中生的复原力水平,进一步根据生态系统理论、复原力动态模型及系统模型,分析家庭环境中的亲子关系和家庭学习环境对初中生复原力的影响及其机制。研究通过回归分析以及中介效应检验,结果表明:(1)亲子关系、家庭学习环境对初中生的复原力水平有显著的预测作用;(2)自尊在亲子关系、家庭学习环境对复原力的影响中起部分中介作用,即积极的亲子关系、良好的家庭学习环境能够通过加强初中生的自我肯定、减少其自我否定来提高其复原力水平。据此,提出提高初中生复原力水平的相关建议。

儿童语用发展取效行为的语力探讨——以认知语言学为视角

认知语言学与语用学关系密切,语用学无论是在方法论上还是在理论上都对认知语言学起到导向作用。在儿童语用发展取效行为的力-动态模型中,儿童语用发展取效研究中的语力被赋予了更加清晰合理的定义,我们将其定义为:在言语互动中,通过话语交际意图(目的)、社会域因素,儿童向受话人(父母、看护人、同伴等)实施力量,旨在借助于力的作用使受话人的状态发生变化,突显力-动态模型的语用特点,为从认知角度研究儿童语用发展指明方向,重新定位儿童语用发展。

双稳定器预弯曲钻具组合防斜特性动力学评价方法

直井的防斜打快一直以来都是钻井领域的难题。预弯曲底部钻具组合防斜打直技术利用预弯曲结构引导钻具组合变形产生较大的动态降斜力,可实现动力学防斜打快目的。然而预弯曲钻具组合防斜特性的动力学定量评价仍是难题。针对双稳定器预弯曲底部钻具组合,笔者在Jansen建立的动力学模型的基础上建立钻头处动态侧向力模型,将仿真得出的A截面处的涡动轨迹数据应用到动态侧向力计算中,最终通过涡动轨迹图、动态侧向力分布时程图和平均动态侧向力对此类钻具的防斜特性进行快速且直观的评价。最后通过编制的计算机程序对不同井斜角和转速条件下的防斜特性进行了仿真计算,仿真结果表明:(1)随井斜角增大,降斜力增大;(2)随转速提升,钻具防斜特性可分为稳定降斜、不稳定降斜及丧失降斜能力3个阶段;(3)在不同井斜角下,第一、第二临界转速随井斜角增大而增大。

言语行为之语力视角浅析苔丝的悲剧

在《伯德家的苔丝》中,苔丝被刻画成一位天生丽质、美丽纯洁的女性。尽管在性格上她是那么的完美,聪明、可爱、勤劳善良,然而当她在无知的情况下被亚雷克侵犯后,等待苔丝的不是社会的同情和怜悯,而是人们的异样眼光和唾弃。苔丝和克莱尔之间的言语行为折射出社会和世人对她的无情。言语行为中存在着语力,讲话者通过话语对听话者实施了一个力,这个力能够克服并改变听话者的状态。社会文化因素(礼貌因素、身份认同感、真诚、讲话双方社会地位等)不仅影响语力,同时又能体现一个时代的社会道德。文章将借助语力——动态模型,从语力的视角对《苔丝》中的言语行为进行社会文化因素和语力之间关系的分析,进一步揭示苔丝悲剧产生的原因。

言语行为中取效行为和取效效果的认知研究

取效行为因其不确定性而成为言语行为理论的薄弱之环。本文继承取效效果的概念，从认知语言学的视角对其定义进行重新梳理，在此基础上利用Talmy的力动态模型对言语行为中的取效行为进行图式性描述和分类．并选取《红楼梦》中的案例进行运用分析和证明，得出的结论如下：（1）取效效果是听者的认知过程，它包括说者发出话语行为、听者接收后通过语言理解机制进行理解并作出相应反应。取效效果决定取效行为，而取效行为可以作为取效效果分析的依据；（2）取效行为有4种分类。本文从理论上弥补言语行为理论的不足，在实践中证明认知语言学的阐释力度，为力动态模型与言语行为理论的结合做出实践上的尝试。

力动态视角下汉语“使”字句的语义构建——一项基于语料的调查

本研究基于Wolff提出的力动态模型,结合莫言14部小说中的200条语料探讨“使”字句的深层语义构建与表层表达之间的关系,并进一步对这一语义组成成分的原型和非原型构建进行阐释。研究结果表明:(1)相同的表层元素“使”在深层语义上可以构建致使、使能、阻止三类不同的语义元素;(2)深层语义构建的致使类、使能类和阻止类原型的主要特征为致使结果产生或未产生的确定性。这一调查旨在验证和发展Wolff对致使构式语义构建的研究,也为认知语言学面临的“同一形式多种用法”的挑战提供一个新的视角。

“A BECAUSE B”构式的“力动态-注意”认知识解模型

本文基于Talmy(2015)认知系统交叉模型为'A BECAUSE B'构式提出了一个'力动态–注意'认知识解模型。根据这一模型,本文将注意系统和力动态系统相结合,动态考察了'A BECAUSE B'构式在语义构建中的三个层级及其互动过程。笔者发现,该构式含有三大语义范畴:(1)力动态作用下对抗或和谐类'致使义',包括三类基本模式:BECAUSE-致使型、 BECAUSE-阻止型以及BECAUSE-使能型;(2)力动态条件下各种'结果义'及其实现状态;(3)整个语义构建过程中注意分布与突显。这一发现解决了以往研究中受因事件和使因事件表征顺序与语义突显问题,澄清了该构式既构建概念框架又表达概念内容的双重作用,阐释了'A BECAUSE B'构式的力动态内涵及其突显意义,并进一步否定了Fodor(1983)提出的'自治模块'说。

四旋翼无人飞行器驱动系统设计与性能测试

针对动四旋翼无人飞行器的高动态、高效率驱动问题,对四旋翼无人飞行器驱动系统的硬件设计、动态模型、能量效率等方面进行了研究,提出了一种基于ATmega88微控制器及I2C总线技术的多旋翼飞行器驱动系统,利用升力测试平台对驱动系统的动态性能与能量效率进行了测试,通过系统辨识实验建立了PWM-旋翼升力动态模型,并分析了供电电压对模型参数和系统效率的影响。实验结果表明,该驱动系统带宽大于10 rad/s,且在每个旋翼300克升力输出时效率高达9 g/W,完全满足四旋翼无人飞行器的设计需要。

Dynamic recrystallization kinetics of as-cast AZ91D alloy

The flow behavior and dynamic recrystallization（DRX） behavior of an as-cast AZ91 D alloy were investigated systematically by applying the isothermal compression tests in temperature range of 220-380 ℃ and strain rate range of 0.001-1 s^-1.The effect of temperature and strain rate on the DRX behavior was discussed.The results indicate that the nucleation and growth of dynamic recrystallized grains easily occur at higher temperatures and lower strain rates.To evaluate the evolution of dynamic recrystallization,the DRX kinetics model was proposed based on the experimental data of true stress-true strain curves.It was revealed that the volume fraction of dynamic recrystallized grains increased with increasing strain in terms of S-curves.A good agreement between the proposed DRX kinetics model and microstructure observation results validates the accuracy of DRX kinetics model for AZ91 D alloy.

Constitutive model for concrete subjected to impact loading

To better design and analyze concrete structures, the mechanical properties of concrete subjected to impact loadings are investigated. Concrete is considered to be a two-phase composite made up of micro-cracks and solid parts which consist of coarse aggregate particles and a cement mortar matrix. The cement mortar matrix is assumed to be elastic, homogeneous and isotropic. Based on the Moil-Tanaka concept of average stress and the Eshelby equivalent inclusion theory, a dynamic constitutive model is developed to simulate the impact responses of concrete. The impact compression experiments of concrete and cement mortar are also carried out. Experimental results show that concrete and cement mortar are rate-dependent. Under the same impact velocity, the load-carrying capacity of concrete is higher than that of cement mortar. Whereas, the maximum strain of concrete is lower than that of cement mortar. Regardless of whether it is concrete or cement mortar, with the increase in the impact velocity, the fragment size of specimens after experiment decreases.

Dynamic mechanical properties and constitutive equations of 2519A aluminum alloy

To analyze the effects of strain rate and temperature on the flow stress of 2519A aluminum alloy, the dynamic mechanical properties of 2519A aluminum alloy were measured by dynamic impact tests and quasi-static tensile tests. The effects of strain rate and temperature on the microstructure evolution were investigated by optical microscopy （OM） and transmission electron microscopy （TEM）. The experimental results indicate that 2519A aluminum alloy exhibits strain-rate dependence and temperature susceptibility under dynamic impact. The constitutive constants for Johnson--Cook material model were determined by the quasi-static tests and Hopkinson bar experiments using the methods of variable separation and nonlinear fitting. The constitutive equation seems to be consistent with the experimental results, which provides reference for mechanical characteristics and numerical simulation of ballistic performance.

Habitat evaluation for target species following deep-water channel project in the Yangtze River

In order to optimize the design of a 12.5 m deepwater channel project and protect the ecological environment, it is necessary to study the habitat evaluation of species in the engineered area. A coupled eco-hydrodynamic model, which combines a hydrodynamic model （ADCIRC） and a habitat suitability index （HSI） model is developed for target fish （Coilia nasus） and benthos （Corbicula fluminea） in the Yangtze River in order to predict the ecological changes and optimize the regulation scheme. Based on the existing research concerning the characteristics of Coilia nasus and Corbicula fluminea, the relationship between the target species and water environment factors is established. The verification results of tidal level, velocity and biological density show that the proposed coupling model performs well when predicting ecological suitability in the studied region. The results indicate a slight improvement in the potential habitat availability for the two species studied as the natural hydraulic conditions change after the deep-water channel regulation works.

Features of pipe transportation of paste-like backfilling in deep mine

Based on the pipe transportation of paste-like backfilling system of a certain deep coal mine,its dynamics process was simulated and analyzed.A two-dimensional dynamic model of extraordinary deep and lone pipe was built by GAMBIT,on the basis of which the simulation was done by implicit solver of FLUENT 2ddp.The results show that hydraulic loss of pipe transportation is less than the pressure produced by gravity,which means the backfilling material can flow by itself.When the inlet velocity is 3.2 m/s,the maximum velocity of 4.10 m/s is at the elbow and the maximum velocity in the horizontal pipe is 3.91 m/s,which can both meet the stability requirement.The results of the simulation are proved to be reliable by the residual monitor plotting of related parameter,so it can be concluded that the system of pipe transportation is safe.

COUPLED PHYSICAL-ECOLOGICAL MODELLING IN THE CENTRAL PART OF JIAOZHOU BAY Ⅱ. COUPLED WITH AN ECOLOGICAL MODEL

Sharples’ 1 D physical model employing tide wind driven turbulence closure and surface heating cooling physics, was coupled with an ecological model with 9 biochemical components: phytoplankton, zooplankton, shellfish, autotrophic and heterotrophic bacterioplankton, dissolved organic carbon (DOC), suspended detritus and sinking particles to simulate the annual evolution of ecosystem in the central part of Jiaozhou Bay. The coupled modeling results showed that the phytoplankton shading effect could reduce seawater temperature by 2℃, so that photosynthesis efficiency should be less than 8%; that the loss of phytoplankton by zooplankton grazing in winter tended to be compensated by phytoplankton advection and diffusion from the outside of the Bay; that the incident irradiance intensity could be the most important factor for phytoplankton growth rate; and that it was the bacterial secondary production that maintained the maximum zooplankton biomass in winter usually observed in the 1990s, indicating that the microbial food loop was extremely important for ecosystem study of Jiaozhou Bay.