波浪对渤海近岸海冰冲击作用的数值模拟

海冰在波浪冲击作用下可能会发生断裂,通过数值模拟定量地描述波浪引起的海冰断裂对海工结构的运行安全以及分析海冰断裂处海水与大气之间的热交换有重要作用。该文利用建立的三维数值波浪水池,将海冰视为刚性平板,结合渤海冬季海冰、波浪的相关参数,研究海冰受波浪冲击的垂向冲击力、水平冲击力、弯矩和最大弯曲正应力随波高、冰长及冰厚的变化规律;并结合渤海海冰的弯曲强度,推断海冰发生断裂的极限参数,结果表明:在渤海海域某些特定条件下,海冰断裂极限波高、冰长和最小冰厚分别为0.504 m、4.273 m和0.098 m。     

一种基于ZigBee的分布式井盖监控系统

随着我国现代经济发展水平的不断提高,城市井盖数目逐渐增加。由于较多井盖被盗,致使路面形成陷阱,危害到过往车辆和行人安全。本文提出了一种基于ZigBee无线网络的智能安全监控系统,解决分布式布控困难、不能实时监控、成本较高的问题。融合GPRS网络,设计相应的嵌入式网关和Web服务器,实现了对缺失井盖的精确定位、自动报警功能。     

苎麻落麻纤维的PVC包覆处理研究

本文研究了PVC包覆处理对苎麻落麻纤维的吸水性、纤维表面状态、纤维单丝强度等的影响.与未处理的落麻纤维增强PP复合材料比较,包覆处理后落麻纤维增强PP复合材料的拉伸和弯曲强度较处理前提高了20%.     

介质覆层对共形PBG结构柱面微带天线性能的影响

设计出一种带有覆层的共形PBG结构柱面微带天线模型并和传统的覆层天线模型在工艺要求上做以对比,分析了所设计覆层PBG微带天线的增益、方向性系数以及效率,和PBG微带天线、传统微带天线进行比较,计算仿真结果表明覆层对微带天线的各项性能有着显著的提高。     

Integrated reliability or travel time and capacity or urban road network under ice and snowfall conditions

In order to evaluate and integrate travel time reliability and capacity reliability of a road network subjected to ice and snowfall conditions, the conceptions of travel time reliability and capacity reliability were defined under special conditions. The link travel time model (ice and snowfall based-bureau public road, ISB-BPR) and the path choice decision model (elastic demand user equilibrium, EDUE) were proposed. The integrated reliability was defined and the model was set up. Monte Carlo simulation was used to calculate the model and a numerical example was provided to demonstrate the application of the model and efficiency of the solution algorithm. The results show that the intensity of ice and snowfall, the traffic demand and supply, and the requirements for level of service (LOS) have great influence on the reliability of a road network. For example, the reliability drops from 65% to 5% when the traffic demand increases by 30%. The comprehensive performance index may be used for network planning, design and maintenance.     

Establishmen and vertification of an improved similitude law for dynamic ice force model test

To study the similitude laws for dynamic ice force model test which is a hot problem in ice mechanics.In this paper,a new modified similitude law for dynamic ice force model test is proposed based on ice-induced virbration theory and two reasonable assumptions.And the new law is vertified with an ice-induced pier virbration example.The numerical calculation results show that,firstly,the error of frequency factor between test value and theory value is small as well as that of displacement and velocity;Secondly,the time scale completely meet the similitude relation,the waveforms anastomotic well,and the phenomenon of offset and omit do not occur;Thirdly,as the damping ratio between prototype and model is nearly equal,the improved similitude law will still be applied.Therefore,the new modified similitude law is feasible to study dynamic ice force model test and can provide reference for the ice mechanics.     

Compressibility of fine-grained soils subjected to closed-system freezing and thaw consolidation

In order to investigate the effects of freezing and thawing on the compressibility of fine-grained soils, freezing and thawing tests and subsequent compression tests with fine-grained soils in an oedometer were carried out. During the freezing, a part of the soils is loosened and another part is over-consolidated under the freezing pressure ?E. The compression curves after the freezing and thaw consolidation are neither different from the normal consolidation curve nor from the rebound curve of an unfrozen soil, until the consolidation pressure ?z = ?E is arrived. Based on the experimental results, a theoretical model has been developed to predict the frost heaves, the thaw-settlements and the compressive deformations of fine-grained soils after the thaw consolidation. The theoretical results are very close to the experimental results.     

牡丹江长江屯站2009年1月冰坝特征及其成因分析

对牡丹江长江屯站2009年1月5~7日形成的冰坝的概况、河道特性、冰坝特征及成因进行分析,以期为冰坝预测及凌汛分析等相关研究提供参考。     

基于UG的芯套双动高速开关阀的仿真研究

运用UG软件对芯套双动阀进行了仿真研究,建立了芯套双动高速开关阀的模拟仿真模型,对阀进行了模拟仿真,并对影响阀性能的因素进行了研究。研究结果对高速开关阀的改进设计有一定的借鉴作用。     

封装板式冰蓄冷系统蓄能模糊建模与分析

针对冰蓄冷系统蓄能的非线性特性,将自适应神经网络应用于封装板式圆罐型蓄冰装置的蓄能初始化和释冷出口温度实时运行的模糊建模,进行了冰蓄冷系统蓄冷量的模糊建模,确定了实验影响因素载冷剂进口温度、载冷剂流速、蓄冷时间的隶属度函数和模糊推理规则.运用减法聚类法和网格法对模型进行初始化训练与运行对比,使蓄冷系统能够跟踪负荷情况.通过调控影响因素的参数,可以更合理地初始化设定蓄冷阶段的蓄冷量.利用该建模程序进行实时释冷出口温度模糊建模策略验证,模型运行平稳.冰蓄冷装置蓄能模糊控制性能的优化保证了蓄冷量与负荷相匹配,实时输出释冷出口温度,进而达到冰蓄冷空调系统优化及经济运行的目标.