淤泥EPS颗粒混合轻质土抗剪强度的影响因素

在疏浚淤泥中添加固化材料和EPS颗粒,制作成淤泥EPS颗粒混合轻质土,既可以资源化利用疏浚淤泥,又可以减少软土的地基处理费用。通过直接剪切试验,获取了淤泥EPS颗粒混合轻质土的抗剪强度参数,即粘聚力与内摩擦角。研究发现:粘聚力随水泥添加量和龄期的增加而增加;在水泥添加量较小时,粘聚力随EPS添加量增加而增加,在水泥添加量较大时,粘聚力随EPS颗粒添加量增加而减小;水泥添加量、EPS颗粒添加量和龄期对内摩擦角的影响不显著,淤泥EPS颗粒混合轻质土的内摩擦角总体分布在20~°35°之间。     

平面交叉口间距对道路交通的影响

平面交叉口间距主要包括信号交叉口的间距、无信号接入间距以及支路与交叉口的间距。研究表明道路上的交通事故率、出行时间、延误随着交叉口、交通信号、接入密度的增加而增大。总结分析了平面交叉口间距对道路交通的影响,并给出了一些参考性的建议。     

高速网络用户接入认证技术研究

自网络诞生以来,认证（authentication）、授权（authorization）和计费（accounting）体制（AAA）成为其运营的基础.网络中各类资源的使用,都由认证,授权,计费来管理.随着网络规模的扩大,传统的认证方式已不能适应用户数量的急增和宽带业务多样化的要求,需要采用新方法对用户的接入进行控制和配置.因此,针对不同的网络环境,提出了不同的网络用户接入认证技术.通过分析和比较,阐明了各种高速网络用户接入认证技术的特点.     

Demand for rail travel to and from airports

Rail access to airports is becoming increasingly important for both train operators and the airports themselves. This paper reports analysis of inter-urban rail demand to and from Manchester and Stansted Airports and the sensitivity of this market segment to growth in air traffic and the cost and service quality of rail services. The estimated demand parameters vary in an expected manner between outward and inward air travellers as well as between airport users and general rail travellers. These parameters can be entered into the demand forecasting framework widely used in the rail industry in Great Britain to provide an appropriate means of forecasting for this otherwise neglected market segment. The novel features of this research, at least in the British context, are that it provides the first detailed analysis of aggregate rail flows to and from airports, it has disaggregated the traditional generalised time measure of rail service quality in order to estimate separate elasticities to journey time, service headway and interchange, and it has successfully explored departures from the conventional constant elasticity position.     

具有迟滞模拟记忆功能的奥迪盘式制动器可变线性模型

本文以奥迪１００盘式制动器为研究对象，建立了一种可模拟制动压力－力矩响应迟清点特性的可变线性模型，首先，介绍在ＪＦ－１３２型汽车制动器试验台上进行防抱制动器模拟试验的方法，其次，在获得大量试验数据的基础上，运用曲线拟合和优化技术，建立制动压力－力矩关系的线性模型，心滞模型为线笥模型，最后，在相同制动压力输入的前提下，把模型的理论计算民试验结果进行对比分析了模型的有效性和精确性。     

Pushing the CZMA Envelope: California: The First State to Litigate the New Federal Law

As noted often by the former California Coastal Commission Executive Director Peter Douglas, the history of how the California coast was saved is a great repository of untold stories. Although the Commission has had a dramatic and tangible impact on California's coastal geography, the public is largely unaware of many of its early accomplishments. This article begins to chronicle the rich stories of California's coastal legacy by telling the story of how the Commission utilized the Coastal Zone Management Act (CZMA) to prevent Southern Pacific Railroad from developing a seven-mile stretch of the Monterey Bay shoreline. In so doing, the Commission helped make possible the creation of the Monterey Peninsula Recreational Trail, a public bicycle and pedestrian path that has grown to sixteen miles in length and runs through the heart of John Steinbeck's world-famous Cannery Row. The controversy also was the subject of the first judicial challenge of a state's federal authority under the CZMA and precluded private commercial and residential development that would have dramatically altered the urban form of the Monterey Peninsula. It is important to tell the story as the Coastal Commission's role in this remarkable accomplishment has been almost completely overlooked.     

Economic Valuation of Coastal and Marine Resources: Bohol Marine Triangle,Philippines

This article provides results on the net benefits generated from the natural resources in the Bohol Marine Triangle (BMT) in the Philippines. The BMT spans over 112,000 ha and its coastal ecosystems are rich in biodiversity and provide economic opportunities to the coastal communities. With a 10% discount rate, the accumulated total net benefits for the BMT resources over a 10-year period is US$11.54 million. Tourism and the municipal fisheries are the most important direct use values of the coastal and marine resources of the BMT accounting for 44% and 39% of the total net benefits. Annual revenues attributed to ecosystems were as follows: coral reefs, US$1.26 million; beach/intertidal area, US$1.12 million; marine waters, US$646,501; mangrove, US$239,561; and seagrass, US$105,990. The large market values indicate the dependence of the local community on the BMT coastal and marine resources. In the same way, non-market values show the important life-support functions of coastal and marine ecosystems. The net benefits reflect the magnitude of potential losses due to improper management of coastal and marine resources in the BMT. This valuation highlights the importance of the coastal services to the BMT economy and draws attention to the benefits the local stakeholders derive from BMT coastal resources. Policy measures can now take into account these values to justify a sufficient investment in coastal management efforts to sustain the flow of coastal services in the interest of current and future generations.     

带回流线的全并联直供系统研究

根据带回流线的全并联直接供电系统的原理,推导出其电流分布及牵引网电压损失,并通过仿真验证了全并联对降低牵引网压损的有效性,同时从仿真结果定性地分析了全并联次数和全并联位置与牵引网电压损失的关系。     

温度对盐渍土抗剪强度和变形特性的影响

为了明确因冻结温度和结晶差异造成的温度对盐渍土抗剪强度和变形特性的影响，以高含盐量和不同盐分类型的盐渍土为研究对象开展试验研究。首先，选用青藏高原察尔汗-格尔木高速公路沿线采集的含盐量为10%~36%的氯盐含量高、硫酸盐含量低的盐渍土土样（HC-1，HC-2）和硫酸盐含量较高而氯盐含量较低的盐渍土土样（CS）3种高含盐量盐渍土作为试验土样，对3种土样进行冻结温度试验，验证其降温至-20℃时，土体不会发生冻结。其次，在5个不同控制温度（-20℃、-10℃、0℃、10℃和20℃）下，分别进行盐渍土直剪试验以得出温度与抗剪强度参数关系函数。最后，分析温度对抗剪强度和弹性模量的影响，同时，利用数值拟合建立考虑温度影响下的盐渍土抗剪强度和切线弹性模量公式。研究结果表明：当温度由20℃降低至-10℃，3种盐渍土的抗剪强度和初始切线弹性模量均增大后趋于峰值，而随温度继续降低至-20℃后，HC-1和HC-2土样指标呈下降趋势，CS土样各参数结果却趋于稳定；不同含盐类型的盐渍土，温度对其破坏比R_f的影响也不同；在温度由20℃降至-20℃的过程中，HC土样的R_f在-10℃出现峰值，且在较低荷载（100 kPa）下，呈现出先增大后减小的特点，在较高荷载（200，300，400 kPa）下呈现出先增大后趋缓的特点；CS土样的R_f在20℃~10℃、10℃~-10℃和-10℃~-20℃降温段呈现出先增大中趋缓后减小的分段式变化特点。     

基于数字信号处理的直接转矩控制研究

直接转矩控制因控制简单、具有优良的动静态特性，在电机控制中应用越来越广泛。但它在低速区的局限也较多。随着数字信号处（Digital Signal Processing，缩写DSP）技术的发展，使得改善其低速控制特性成为可能。文中简介了直棼转矩控制技术的特点、控制原理及难点，探讨了一种应用DSP技术的直接转矩控制方法。