Material transport from the nearshore to the basinal environment in the southern Baltic Sea: I. Processes and mass estimates

Processes involved in erosion, transport and deposition of cohesive materials are studied in a transect from shallow (16 m) to deep (47 m) water of the SW Baltic Sea. The wave- and current-induced energy input to the seabed in shallow water is high with strong variability and suspended matter concentrations may double within a few hours. Primary settling fluxes (from sedimentation traps) are less than 10 g m⁻² day⁻¹, whereas resuspension fluxes (evaluated from sedimentation flux gradients) are 15–20 times higher and the residence time for suspended matter in the water column is 1–2 days. Settling velocities of aggregates are on average six times higher than for individual particles resulting in an enhanced downward transport of organic matter. Wave-induced resuspension (four to six times per month) takes place with higher shear stresses on the bottom than current-induced resuspension (three to five times per month). The short residence time in the water column and the frequent resuspension events provide a fast operating benthic–pelagic coupling. Due to the high-energy input, the shallow water areas are nondepositional on time scales longer than 1–2 weeks. The sediment is sand partly covered by a thin fluff layer during low-energy periods. The presence of the fluff layer keeps the resuspension threshold very low (<0.023 N m⁻²) throughout the year. Evaluated from 3-D sediment transport modeling, transport from shallow to deep water is episodic. The net main directions are towards the Arkona Basin (5.5×10⁵ t per year) and the Bornholm Basin (3.7×10⁵ t per year). Energy input to the bottom in deep water is low and takes place much less frequently. Wave-induced resuspension occurs on average once per month. Residence time of particles (based on radioactive isotopes) in the water column is half a year and the sediment accumulation rate is 2.2 mm year⁻¹ in the Arkona Basin.     

轨道检查车技术的发展与应用

我国铁路实施提速战略对加强轨道动态检查力度、及时掌握轨道质量状态提出了更高要求.介绍国外铁路发达国家轨道检查车的技术特点,认为激光摄像测量技术已成为当前国际轨道检测技术发展的主流.提出我国轨道检查车的发展方向,阐述其应用情况.     

Longitudinal Tire Dynamics

This article begins with a brief review of the traditional concept of lateral relaxation length. The review illustrates that this concept yields a useful approximation which can be used with semi-empirical tire models which assume lateral forces are a function of steady-state slip angles. The article then presents an analogous derivation for longitudinal slip. Like its lateral counterpart, the derivation yields an approximation for transient longitudinal slip which can be used with tire models which assume longitudinal forces are a function of steady-state longitudinal slip. It is shown that, like the relaxation-length-based lateral slip angle, this formulation for longitudinal slip yields the ability to compute shear forces at the tire/road interface for either high or low speed applications, a necessary feature of simulations which support human in the loop driving simulation. Like traditional kinematically-based longitudinal slip, the transient formulation presented here is coupled with the wheel spin equation, and it shares the characteristic that it is very stiff compared to the equations of vehicle motion. This characteristic is a challenge impeding the real-time calculations required for driving simulation. The paper shows that local linearization of the wheel spin equations coupled with analytical solutions of the transient longitudinal slip formulation provide the basis for both insight into the longitudinal dynamics of the tire and for integrating the model in real-time.     

Cost assessment for abyssal seafloor waste isolation

We develop an integrated model for estimating the internal cost of abyssal seafloor waste isolation. The model captures the major economic, engineering, geographic and social factors that influence the management cost for sewage sludge and municipal incinerator ash. Considering five representative metropolitan areas and five proposed abyssal study sites, we apply this model to produce cost estimates for four deep-ocean waste delivery system concepts. The results show that the unit cost depends primarily on regional waste volume, the marine delivery system and transportation distance. Based on available data, the abyssal ocean option may be competitive with present land-based disposal costs in New York City. The option is less competitive in other metropolitan areas.     

宋丽关系与密州板桥镇

关于宋朝与高丽王朝的关系史,很多学者已作了大量的研究,但多是集中在两个国家总体上的政治经济文化交流,从地方史角度出发的不多,即使有也大多是对两浙地区比如明州(今浙江宁波)和杭州等地的宋丽关系史的考察,研究山东胶州地区中韩关系的则很少.对于山东胶州的问题也有人研究,李晓先生曾在<海交史研究>(1985年第1期)上发表过<山东胶州港兴衰问题初探>,介绍了胶州港在北宋前、宋金元初及明清两代的兴衰过程,不过,重点是在港口历史沿革,不在宋丽关系.所以本文拟以胶州(即宋朝历史上的密州板桥镇)为中心对宋丽关系作一初步探索,以就正于诸位前辈.     

转臂式轴箱定位装置等效刚度计算与分析

文章从能量守恒定律出发，结合转臂式轴箱定位装置的结构特点，通过分析其受力状况和运动几何关系，在充分合理简化的基础上，推导出通用的转臂式轴箱定位装置的垂向、纵向和横向等效刚度计算公式，并对我国典型动车组的转臂式轴箱等效定位刚度进行了计算。     

Benefits and challenges of controlling a LED AFS (adaptive front-lighting system) using fuzzy logic

The vehicular illumination system has undergone considerable technological advances in recent decades such as the use of a Light Emitting Diode (LED) Adaptive Front-lighting System (AFS), which represents an industry breakthrough in lighting technology and is rapidly becoming one of the most important innovative technologies around the world in the lighting community. This paper presents AFS control alternatives using fuzzy logic (types 1 and 2) to determine its operating parameters taking into consideration the road conditions in the state of São Paulo (Brazil). Fuzzy logic is a well-known extension of the conventional (Boolean) logic that enables the treatment of uncertainty present in the information through the definition of intermediary membership values between the “completely true” and the “completely false”. This technique or modeling strategy is particularly important when a multi-parameter decision must be taken or the decisions are based on the human knowledge. The results show the potential of the methodology proposed and its suitability for light control providing safer nighttime driving.     

青藏铁路冻土路基沉降变形预测

青藏铁路试验工程北麓河试验段冻土路基沉降变形现场试验研究表明:即使路基下冻土人为上限有所上升,冻土路基仍会产生较大的沉降变形。这种变形主要来自原天然上限以下高温—高含冰量冻土升温引起的压缩变形。路基下多年冻土的升温幅度、高含冰量冻土层厚度和路堤高度越大,路基的沉降变形量就越大。数值计算结果表明:在路堤填土满足临界高度,且考虑青藏高原年平均气温逐年上升的条件下,青藏铁路北麓河试验段冻土路基在未来50年内的总沉降量可能达到30 cm。因此,要控制冻土路基的沉降变形,必须采取主动降低多年冻土温度的工程措施,单纯靠增加路堤高度的传统方法不能解决问题,甚至适得其反。     

计算机联锁模拟培训系统

主要介绍了计算机联锁培训系统平台的研制开发。系统依靠计算机技术、控制技术、网络技术，完全模拟计算机联锁设备的显示界面与操作方法，做到与现实设备操作一致，使操作人员如同亲临现场，从而达到使电务工作者能进行培训、演练和开发的目的。     

皂河三线船闸闸室墙倒角砼表面质量控制措施

在倒角斜面砼的施工中如何降低砼表面的蜂窝、麻面、砂斑、砂线，一直是工程施工的一个难题。通过对皂河三线船闸闸室墙倒角施工工艺的改进，斜面砼表面质量得到了较好的控制。