摊铺机熨平板动态特性分析与测试

为了提升摊铺机熨平板的振动响应效果,改善其动态特性,首先建立了熨平板的动力学模型,根据拉格朗日定理对运动微分方程进行了求解,并通过虚拟样机仿真技术研究了熨平板箱体振幅响应与振动器频率的关系.然后提出了利用薄膜压力传感器测量振捣锤对地压力的方法,研究振捣锤对沥青料的压力与振捣频率的关系.最后在模态叠加理论的基础上,提出熨平板振动形态的测试方法,绘制出不同工作条件下的熨平板振动形态.结果表明,振动器工作频率在30~40Hz范围时,熨平板箱体振幅响应较明显;振捣机构工作频率在15~20 Hz范围时,振捣锤对沥青混合料的压力较小;振捣频率为15 Hz、振动频率为40 Hz的工作条件下,熨平板振动形态最平整,从而可以提升沥青层的平整度和密实度.     

沥青混凝土摊铺机熨平机构的动力学实验研究

为研究沥青混凝土摊铺机的熨平板结构参数和其有关振动压实部件的运动参数的关系, 对国内新生产的一种摊铺机的熨平板机构进行了动力学实验研究－ 得到了在一种激振频率下前后压实梁及熨平板平台在不同受压介质刚度下的加速度信号和其变化特征等, 揭示了压实梁等在不同压实介质下的运动规律     

摊铺机自动调平熨平板运动学模型与特性

为了研究摊铺机的摊铺特性,提高摊铺平整度和弯道变坡控制精度,通过对配置自动调平系统摊铺机工作装置的作业机理和运动学分析,建立了摊铺机熨平板的运动学模型,确定了自动调平系统传感器安装位置、摊铺机作业速度、地面输入激励函数与熨平板输出响应之间的关系;采用正弦函数和阶跃函数分别模拟路面平整度激励和弯道变坡输入激励,建立了输出响应模型,应用Matlab软件在常用摊铺速度下进行了仿真研究。研究结果表明:调平系统传感器与熨平板后沿的安装距离越近,熨平板的随动性越好,变坡响应越快;安装距离越远,滤波效果越好,平整度越高;传感器的安装位置应在熨平板大臂的1/4~1/2之间,变坡控制要求高时取小值,平整度控制要求高时取大值,进行综合控制时取中间值。     

多功能摊铺机振捣压实机构动力学仿真

针对多功能摊铺机在工作过程中单偏心块振动器会产生水平力而影响摊铺质量的问题,提出了双偏心块振动器机构。建立了双偏心块振动压实机构4自由度振动系统的微分方程,对系统的固有频率进行了分析。基于现代控制理论,建立了压实机构的状态空间模型,利用MatLab/Simulink进行仿真,研究了振捣器、压实梁和振动器的参数变化对该系统动态特性的影响。理论分析和仿真结果表明双偏心块振动器机构既能平衡水平力,又能产生双倍的压实力;系统的固有频率将会随着熨平板质量的增加而减小;振捣器和压实梁的参数对熨平压实装置的影响很大,而     

沥青混凝土摊铺机熨平装置的动力学分析

为了解决沥青混凝土摊铺机熨平装置运动学模型存在的问题,分析了摊铺机的摊铺过程以及混合料与熨平板之间的作用关系。经过分析,认为摊铺过程中熨平板与混合料的作用面积并不一定是熨平板的全部面积,而是有可能部分接触,其面积大小为一个动态的变化过程,在此基础上,导出了熨平装置的动力学模型。     

提高沥青路面平整度的几个关键环节

介绍了摊铺机熨平板的浮动原理,分析了影响路面平整度的因素,对摊铺过程中自动找平装置的应用、摊铺机作业注意事项及关键环节进行了探讨。     

沥青混凝土摊铺机液压系统的常见故障

根据多年维修保养沥青混凝土摊铺机所积累的经验,对沥青混凝土摊铺机液压系统常见的液压油过热、螺旋布料器不能正常工作、熨平板提升困难、摊铺机跑偏或不行走和料斗不能正常合拢等故障进行了分析,供大家参考.     

公路施工中沥青路面摊铺机的应用分析

在公路的沥青路面施工中,经常出现铺层厚度不均、平整度较差、接缝明显等现象,这些现象跟摊铺机在施工作业中有着直接的关系。本文通过介绍摊铺机熨平板宽度的选定原则、摊铺厚度的确定,从而对摊铺机在施工中的正确规范操作方面的应用进行分析。     

控制沥青路面弯道摊铺质量方法的探讨

阐述了沥青混凝土摊铺机的工作原理及其对弯道摊铺的影响，介绍了浮动熨平板的运动学模型和弯道摊铺横坡控制的设计方法，并对弯道摊铺技术的试验研究进行了探讨。     

公路水泥混凝土路面轨模式摊铺机施工研究

轨模式摊铺机施工是由支撑在平底型轨道上的摊铺机将混凝土拌和物摊铺在基层上。摊铺机的轨道与模板是连在一起的,安装时同步进行。轨模式摊铺机施工混凝土路面包括施工准备、拌和与运输混凝土、摊铺与振捣、表面整修及养护等工作。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-