某加宽桥梁桥梁动载试验

桥梁的动力性能是评价桥梁运营状况和承载能力的重要指标之一。现对某扩宽桥梁的加宽部分进行了桥梁动载试验,测定桥梁结构的自振特性。用以验证设计理论、计算方法的合理性;评价桥跨结构在动荷载作用下的工作性能;判别桥跨结构是否处于安全振动工作状态;预测桥梁运营状况,为桥梁管理提供技术依据。并为以后同类桥梁检测及试验提供一定经验。     

某钢筋混凝土双曲拱桥静载试验与分析

桥梁检测是保证桥梁安全运营的重要手段。在桥梁检测项目中，静载试验能够了解桥梁实际工作状态和承载能力，提供直接可靠的应力应变数据。通过对某钢筋混凝土双曲拱桥进行静载试验，对应变、挠度进行了分析，并对实验结果和有限元计算结果进行了对比分析，试验荷载作用下的应变校验系数介于0．8～1．06。实验结果为该桥提供了准确的技术状况评定，从而为该桥梁的正常运营及加固改造维修提供了可靠的试验数据支持。     

某箱形连续梁桥静动载试验与分析

在桥梁检测项目中,静载试验能够了解桥梁实际工作状态和承载能力,提供直接可靠的应力应变数据。动载试验能够测得桥梁的刚度和整体性。通过对某钢筋混凝土箱型连续梁桥进行动静载试验,对应变、挠度和频率进行分析,并对实验结果和有限元计算结果进行对比分析,实验结果为该桥提供了准确的技术状况评定,从而为该桥梁的正常运营及加固改造维修提供了可靠的试验数据支持。     

钢筋混凝土箱形拱桥的安全状态评定——以甘青公路享堂大通河大桥加固工程为例

随着交通负荷的加大,许多桥梁都出现超负荷运营的状况。为正确评价桥梁的安全状态,给桥梁运营养护部门提供决策依据,往往需要进行一些必要项目的检测。通过介绍上承式箱形拱桥的检查检测过程,描述了常规桥梁检查检测的内容和方法。     

厦门市角嵩路连续梁桥静动载试验研究

对厦门市角嵩路连续梁桥进行了成桥静力和动力荷载试验及分析,通过现场静动力荷载试验,测得其各种力学指标和性能指标,并与理论计算的结果及相应规范要求进行比较,从而对桥梁整体性能和结构安全做出评价,以确保桥梁主体结构处于完好的技术状态和良好的使用状态,保证桥梁投入使用后的安全运营.试验结果表明,该桥设计和施工质量优良,桥梁工作状态和各项力学性能满足规范和设计要求.     

关头坝大桥振动监测系统

为了对关头坝大桥的结构健康状态和安全寿命作出正确评估,如实反映大桥的结构安全状态和运营安全信息,建立了桥梁振动监测系统.通过对大桥进行结构危险性分析,确定7个监测断面,布置14个3轴加速度传感器.设计了关头坝大桥振动监测系统数据采集及传输模块,此模块由12位精度模数转换芯片、89C52、RS232、DS1216等芯片组成,完成一次数据采集共需约5 ms.设计了大桥数据采集与分析管理系统,可对监测数据进行分析评估,为桥梁的养护、维修与管理提供决策.监测数据结果表明:桥梁振动监测系统可以实时地对桥梁结构状态进行监测与评估,为大桥在特殊气候、特殊交通条件下或运营状况严重异常时触发预警信号.目前,该系统正在为大桥的运营、管理和维护提供决策依据,对确保大桥的安全运营发挥着重要作用.     

某既有桥梁加固后动载试验分析研究

在桥梁承载能力评定中,动载试验能了解结构自身的动力特性以及结构抵抗受迫振动和突发荷载作用的能力,通过工程实例介绍了动载试验的基本方法,对既有桥梁加固后进行模态测试和行车试验,以试验依据判断结构的实际工作状态,也为桥梁后期运营使用提供科学的指导依据.     

基于吊杆损伤的斜靠式拱桥动力特性仿真分析

借用MIDAS/Civil有限元程序,对吊杆的不同损伤状态进行了仿真,分析对比了桥梁完好状态和不同吊杆损伤情况下的桥梁动力特性,这对正确认识斜靠式拱桥在不同状态下的结构动力特征,合理评价桥梁运营阶段的健康状况提供了参考和基础性数据.     

基于静载试验的桥梁评价技术研究

如何应用静载试验对桥梁的运营承载能力进行合理评价始终是桥梁检测的一个重点。本文通过静力荷载试验,依据试验结果对该桥的工作状态做出了合理的评价。通过采取有针对性的限制措施,延长桥梁的使用寿命。     

某拱桥加固后静力荷载试验

为了解小凌河大桥加固后的结构性能,对大桥进行了静载试验,测定了结构的强度和刚度,并将实测值与理论计算值进行对比分析,结果表明桥梁的工作状态符合设计要求,工作性能稳定。同时为以后桥梁的安全运营提供了必要的技术参数。     

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.     

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.     

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the