软土地段斜交涵洞的受力分析与处治设计

文中详细分析了斜交涵洞端部的受力特点。计算结果表明,当斜交角度越大、涵底与地基土的摩擦系数越小时,推力及扭矩越大。笔者建议软土地段的涵洞应尽可能做成正交,工程实践表明,即使斜交,斜交角度尽量不超过20o。     

Cross-shelf circulation and phytoplankton distribution at the summertime New England shelfbreak front

We investigate aspects of the secondary (cross-shelf) circulation at the Middle Atlantic Bight shelfbreak front using high-resolution data collected on the New England Shelf in August 2002. The alongshore shelfbreak jet coincides with the front at the seaward edge of the cold pool (remnant winter shelf water) and there is a suggestion of a cross-stream convergence centered at the jet core. Despite indications of convergence we found no evidence of a surface subduction on the seaward side of the front. At depth 70 m near the shelfbreak there was a patch of chlorophyll, located within a local temperature–salinity maximum which, though significantly below the euphotic zone, appeared to be photo-acclimated and viable. The chlorophyll feature could be the result of a local subduction by a larger scale eddy circulation seaward of the front.Dye tracer experiments directly observed the convergence at the foot of the shelfbreak front and subsequent upwelling of bottom boundary layer water along the shoreward side of the shelfbreak front. But, we found no evidence that this upwelling influenced productivity at the front. Further, since there was no cross-shelf maximum in subsurface chlorophyll at the front, we conclude that this productivity is in general, sustained by a broadly distributed local vertical nutrient flux from an underlying nutrient reservoir.     

非机动车廊道布局规划——以杭州市非机动车交通发展战略规划为例

为使非机动车道网规划达到机非分流、便捷高效的目标,以杭州市为例,对廊道布局规划进行了探讨。在非机动车交通需求预测和流量分配的基础上,结合边界条件、用地性质和面积,进行非机动车慢行区划分;通过分析各类慢行区非机动车交通特征和组织策略,提出相应的廊道网络形态;进而根据非机动车出行高发区和换乘枢纽分布确定廊道布局的控制点,基于最短路径流量分配确定廊道布局的期望走廊,参照规划和现状道路条件确定廊道布局的具体路径,依据截面流量、规范推荐和公众意愿调查确定廊道布局的合理间距;最后在控制点、期望走廊、道路条件和廊道间距分析结果引导下,得到杭州市非机动车廊道布局方案,并验证了鼓励近距离出行的规划理念同时也符合交通需求预测分析的结果。     

降雨条件下固定目标防护暴露区的计算仿真

干扰暴露区的计算在现代电子战中有着极其重要的作用。但在实际应用中,干扰暴露区的计算常受到干扰样式、气象条件和自然环境引起的杂波、多径效应等诸多因素的影响。为此,将降雨衰减因子引入雷达方程,仅就固定目标防护问题中的干扰暴露区计算进行仿真研究,并针对不同情况进行对比。结果表明,该方法可提高干扰暴露区计算的准确性,为降雨条件下的战场仿真提供了新的途径。     

舰船总体区域设计技术研究

通过分析舰船总体功能,开展了舰船总体区域划分,给出了总体区域划分、分段区域划分的设计准则;从技术和管理角度阐明了区域设计的控制过程,并就区域施工设计向生产设计的信息传输进行了分析,给出了自动转化方案,为区域设计向区域建造的转化提供了技术基础。同时,在文中提出了模块化对象封装设计方法应作为舰船总体区域设计中的重点予以关注。     

黄墩大桥索塔锚固区传力途径和受力分析

为验证索塔锚固区设计的合理性,了解索力在锚固区的传递途径以及主要板件的受力特点,通过全真的实体有限元模型对黄墩大桥索塔锚固区进行了计算分析。计算结果显示:锚固区的索力传递途径明确,能适应斜拉桥的受力特点;钢横梁两端受压,中间受拉,除锚固板与腹板的连接焊缝附近有应力集中现象外,其余板件的应力值均小于材料屈服强度;混凝土塔壁主拉应力较小,配置普通钢筋即可,不必设置环向预应力筋;位于牛腿焊缝附近的剪力钉受力较大,通过加密调整后满足受力要求。上述结果表明黄墩大桥索塔锚固区设计合理、实用,能满足结构受力需要。     

乌江岩崩堵江航道整治方案试验研究

根据乌江岩崩堵江航道特点 ,采用河工模型与船模试验相结合方式进行整治方案研究 ,取得了良好效果 .本文简要介绍了模型设计、验证及方案试验情况 .该工程现已完成 ,岩崩航道的通航条件大为改善 ,整治效果显著 .     

四车道高速公路部分占用超车道交通控制区交通特性及通行能力研究

针对四车道高速公路部分占用超车道交通控制区开展研究,得到交通控制区各主要区段行车道和超车道上的流量分布曲线,换道方向与换道率曲线,速度分布曲线,标定 Greenshields 模型并据此确定各主要区段的道路通行能力. 研究结果表明：当交通量处于较低水平时,超车道的利用率较低,只有正常水平的20%左右,此时应对车道划分、车道设置及交通控制方式等进行优化调整;较低交通量水平下,交通控制区的平均车速、运行速度等均较高,宜使用运行速度作为限速值的取值依据;施工作业区段的道路通行能力只有正常路段的 89%左右,在保障交通安全的前提下应着力提高瓶颈路段的道路通行能力,并将瓶颈路段的断面通行能力作为是否进行强制分流的依据.     

The use of digital filter initialization to diagnose the mesoscale circulation and vertical motion in the California coastal transition zone

A dynamical method of initializing the primitive equations is tested and used to diagnose the three-dimensional circulation associated with jets and eddies as found in the California coastal transition zone (CTZ). The initialization method, referred to as digital filter initialization (DFI), was recently developed by [Monthly Weather Review 120 (1992) 1019] for use in an intermittent data assimilation system in the atmosphere. The ability of DFI to recover the mesoscale ageostrophic circulation associated with finite amplitude jets and eddies in the ocean is first demonstrated using control data produced by simulations with a primitive equation model. The DFI method is then applied to synoptic hydrographic data collected during several California CTZ surveys in the summer of 1988. The diagnostic results indicate the existence of jets, eddies, and filaments in the CTZ domain with maximum horizontal currents of the order of 0.6 m/s at the surface. Currents associated with such jets and filaments are coherent to a depth of over 500 m. The surface currents associated with a prominent cool filament are generally confluent, and weakly convergent on average, along the 270 km offshore extent of the filament. Meanders in the jet display convergence and downwelling upstream of pressure troughs and divergence and upwelling downstream of the troughs. Maximum vertical velocities at 100 m are of the order of 10 m/day. This result is consistent with independent estimates of subduction rates made from biological studies in this and similar coastal filaments in the CTZ program.     

物流企业在中国-东盟自由贸易区内运营财务核算问题研究

文章通过对当前物流企业财务核算体系存在的问题进行分析,探讨了加强物流企业在东盟自由贸易区内运营财务核算的必要性,提出了建立物流企业在东盟自由贸易区内运营财务核算的对策。