从河床演变观点评荆江碾子湾河道的整治

长江下荆江河段的碾子湾河道长度只有２８ｋｍ,分布着严重碍航的碾子湾浅滩,藕池口浅滩,石首锐弯与被泥沙沉积的石首港。１９８０年以来碾子湾河道发生严重的侵蚀与沉积。１９９５年２月至３月因碾子湾浅滩严重沉积使航道恶化,断航达２９天,约５００多艘江轮与６万多名旅客相继滞留在碾子湾河道上,在长江中游近代航运史上实属罕见。本文从近４０多年来碾子湾的河床演变和鱼尾洲护岸工程角度评述碾子湾道与石首港恶化的原因,这     

高速公路中通道桥的设置

阐述了高速公路中通道的设置原则、设置条件、设置要求,同时提出通道设置时应注意的问题,从而保证通道设置的合理性、科学性和经济性。     

High speed rail passenger segmentation and ticketing channel preference

A multi-channel strategy for the purposes of marketing and ticketing has been widely employed in various fields, including the transportation industry, yet few transportation studies have investigated ticket channel-related issues. This study thus adopts Taiwan High Speed Rail (THSR) as a case study to identify passengers’ perceptions regarding key factors that affect the channel preference through which they receive their services, particularly across a four-stage ticket purchasing process, including information enquiry, booking, payment, and ticket pick-up. To investigate these key factors, we base the framework of our research model upon customers’ perceived value perspective, adopting a multinomial logit model to examine the influence of channel attributes on HSR passengers’ preferences. The relationship among the decisions made by these passengers at each ticket purchasing stage is also examined. The findings of our study demonstrate that perceived risk, perceived benefit, and perceived ease of use are critical factors influencing passengers’ channel preference throughout the ticket-purchasing process. Perceptual differences are proven to exist due to various demographic factors and trip characteristics. The conclusions of this study have implications for THSR management to design appropriate ticketing channel services for certain types of passengers and can also be generally applied to multiple distribution channels in conventional railway system and intercity bus services.     

改善航道条件促进沿江经济发展

本文在分析长江航运发展现状的基础上,阐述了影响长江航道,尤其是江苏段航道发展的因素,提出了提高长江下游江苏段航道通航效率的对策。     

Matching biological traits to environmental conditions in marine benthic ecosystems

The effects of variability in environmental conditions on species composition in benthic ecosystems are well established, but relatively little is known about how environmental variability relates to ecosystem functioning. Benthic invertebrate assemblages are heavily involved in the maintenance of ecological processes and investigation of the biological characteristics (traits) expressed in these assemblages can provide information about some aspects of functioning. The aim of this study was to establish and explore relationships between environmental variability and biological traits expressed in megafauna assemblages in two UK regions. Patterns of trait composition were matched to environmental conditions and subsets of variables best describing these patterns determined. The nature of the relationships were subsequently examined at two separate scales, both between and within the regions studied. Over the whole area, some traits related to size, longevity, reproduction, mobility, flexibility, feeding method, sociability and living habit were negatively correlated with salinity, sea surface temperature, annual temperature range and the level of fishing effort, and positively associated with fish taxon richness and shell content of the substratum. Between the two regions, reductions in temperature range and shell content were associated with infrequent relative occurrences of short-lived, moderately mobile, flexible, solitary, opportunistic, permanent-burrow dwelling fauna and those exhibiting reproductive strategies based on benthic development. Relationships between some traits and environmental conditions diverged within the two regions, with increases in fishing effort and shell content of the substratum being associated with low frequencies of occurrence of moderately mobile and moderately to highly flexible fauna within one region, but high frequencies in the other. These changes in trait composition have implications for ecosystem processes, with, for example, reductions in permanent-burrow dwellers within one of the regions potentially compromising the ability of the assemblages to process and store chemicals and waste products. However, the connections between environmental conditions and trait composition are complex and incorporate many factors. Experimental investigations will be necessary to determine the extent and consequences of these important relationships.     

Houston-Galveston Navigation Channel: Blueprint for the Beneficial Uses of Dredge Material

The beneficial uses of dredge material from the Houston-Galveston Navigation Channel (HGNC) to create large-scale wetlands represents a blueprint for other large U.S. ports. The port authority's interagency coordination team, the Beneficial Uses Group (BUG), successfully developed an innovative 50-year plan to deal with dredge material disposal from the channel widening and maintenance project. The creation of intertidal wetlands will initiate the restoration of the United States' second most productive estuary, in concert with the Galveston Bay National Estuary Plan, while capturing increasingly scarce government financing for port maintenance and improvement operations. An overview of the various beneficial uses of dredge material in the HGNC enlarging project is presented with a detailed investigation of the Bayport Demonstration Marsh. The HGNC project is analyzed as a prototype for successful extensive wetland creation ventures, and several key design criteria for similar large-scale marsh creation projects are given.     

客运专线通信系统可靠性测试探讨

概述客运专线联调联试的通信系统可靠性测试,介绍传输系统、GSM-R系统、调度系统、数据网、综合视频监控系统的传输网络结构。通过功能测试,给出传输系统保护倒换过程对调度系统、GSM-R系统、数据网、视频监控系统业务的影响,以及调度系统、GSM-R系统的2Mb/s通道保护倒换对业务的影响,验证客运专线通信系统的可靠性。     

ECC路由不通导致传输网元脱管故障分析及排除

嵌入式控制通道（ECC,）,用于SDH网元间通信,传送TMN信息,实现网管对非网关网元的管理。通过对一例ECC路由不通导致传输网元脱管的故障进行分析,了解ECC原理,掌握ECC故障处理的方法和技巧。     

时间扩展畸变信道中鱼雷宽带自导的最佳检测器

介绍了为解决畸变信中鱼雷宽带自导信号检测问题而研究的副本相关检测器和副本相关积分检测器,并绫出了其检测性能的理论分析和对比试验结果,研究结果表明,在时间扩展畸变信道中,副本相关积分器具有稳健的,最佳的检测性能。     

西安铁路枢纽通信骨干传输网的建设研究

根据西安铁路枢纽通信网络存在的问题分析,结合通信传输技术的发展,确立采用OTN技术搭建枢纽骨干传输网。通过分析枢纽内的传输系统容量,确定了骨干网的系统规模。结合枢纽现状确定骨干节点设置,根据传输业务内容确定保护方式、波道分配。调查既有光缆资源,明确统光纤运用,构建起西安枢纽的骨干传输网,改善了枢纽内的传输条件,提高了通信网运行的可靠性。