平面桁架结构稳定性实验装置的研制与应用

根据工程实际问题抽象简化,研制了平面桁架结构稳定性实验装置。此实验装置结构紧凑、操作方便。应用此装置开设的结构稳定性实验,因约束形式多种,杆件长度可变,从而形成了不同的力学模型和失稳形式,这对于加强学生综合实践能力培养、深化学生对结构稳定性的理解、评价和思考具有重要的意义。     

多普勒信号频域压缩算法中最佳时窗长的选择

研究基于短时傅里叶变换（STFT）的可变窗长的多普勒信号的频域压缩算法中最佳时窗长度的选择问题，提出了根据系统压缩倍数的要求及信号的局部平稳性，选择STFT时间窗长度的可变窗长的频压缩算法，并得到其简化的二窗法频域压缩算法，仿真结果表明，与固定窗长法相比，二窗法频域压缩算法克服了取固定窗长度时存在的偏差较大的问题，取得了比较满意的仿真结果。     

单双向交通组织衔接交叉口段的可变车道利用

基于交叉口附近车道交通流不对称的状况,分析可变车道的设置方法,提出可变标志板延后起亮和提前关闭时刻的计算方法,并采用2次排队长度、通行能力、延误等指标,综合评估可变车道的利用效用.以上海东方路浦三路为例,调查了早高峰时期交通需求和存在的问题,提出浦三路南段西侧车道利用可变车道的可行性,研究了可变车道设计、相位相序及配时策略、可变标志板的启动和停止与主信号关系.对提出的方案进行评估的结果表明,利用可变车道可以提高单双向交通组织衔接交叉口的通行能力,减少2次排队,降低延误约30%.     

碰撞检测技术研究

通过介绍影响碰撞检测的相关要素,阐述了可变时间片长度的碰撞检测问题,又提出了包围盒方法和距离跟踪算法;这些方法能有效的提高碰撞检测的速度,能较好的解决虚拟现实中的碰撞检测问题。     

基于可变队列长度固定优先级控制策略的话音 Ⅰ.数据单一信道复用系统性能模型

将可变队列长度固定优先级控制策略用于话音/数据单一信道复用系统,推导出了在此环境下的系统性能分析模型,该模型为话音/数据单一信道复用系统在可变队列长度固定优先级策略控制下的性能分析,以及多种控制策略的量化比较提供了方便有效的手段。     

面向变向交通组织的信号控制 交叉口进口短车道设置方法

为解决城市交通流的潮汐特性造成道路资源利用不合理的问题. 引入了交叉口进口道短车道的概念,探讨了有交叉口存在的城市道路变向交通组织方法,以可变车道短车道长度为自变量建立交叉口进口道通行能力模型,并利用VISSIM进行交通仿真检验该模型. 研究结果表明,文中建立的模型具有可行性,同时确定了模型中排队车辆车头间距的最优取值,分析模型可知可变车道长度在一定范围内增加时可以提高交叉口进口道的通行能力.     

WXG-4型圆盘旋光仪存在的问题及改进

本文阐述了WXG-4型圆盘旋光仪在实验测量旋光度时存在的问题和缺点。根据旋光仪的工作原理提出采用长度可变式样品管来测定旋光度的新方法。     

具有变时滞的细胞神经网络的全局指数稳定性

研究具有可变时滞的细胞神经网络的全局指数稳定性问题,得出了可变时滞的细胞神经网络全局指数稳定性的几个充分条件.在实际应用中,设计验证满足这些条件很方便,甚至无须知道时滞的具体形式.因而具有重要的理论意义和应用价值.       

可变自主系统中态势推理方法研究

针对可变自主系统在执行特殊任务的过程中需要实时准确地推理出当前环境态势,并为可变自主系统确定自主等级提供数据支持的问题,提出一个具有事件检测、威胁评估和冲突预测3层结构的态势推理模型.实现了基于模糊逻辑的事件检测方法、基于贝叶斯网络的威胁评估方法和基于模糊逻辑的冲突预测方法.结合具有可变自主系统的水面无人艇执行导航任务...     

可变导向车道作用机理与实例效果评价

针对现在大城市存在的信号交叉口非均衡转向交通状况,对可变导向车道实施效果进行评价. 以杭州市文二路/教工路交叉口为研究对象,在对可变导向车道作用机理进行理论分析的基础上,选取饱和度、停车延误、排队长度、停车次数作为评价指标,对该交叉口可变导向车道实施前后的效果进行定量化评价. 研究结果证实可变导向车道的实施用于应对不均衡转向交通流具有明显的效果.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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