阻抗复合消声器的动态特性分析

VW - 0 2 2 7-B型空压机的噪声源 ,其空气动力性噪声最强。拟在空压机进气口安装阻抗复合消声器 ,本文针对由最优化设计方法获得的阻抗复合型消声器模型 ,在未对消声器实物加工之前 ,根据消声器的图纸及有关数据进行了有限元动力计算 ,从而初步了解消声器的动态特性。由此可避免消声器制造的盲目性及重复实验 ,为设计优良消声器提供新的有效途径。     

多目标、多水源和多用户水资源系统管理的专家系统决策模型

几乎所有的水资源系统都是以多目标、多水源和多用户等为特征，因此其开发与管理过程中的各种决策也都必须坚持这些原则。本文利用现代专家系统技术建立了一种水资源系统管理的专家系统决策模型。该水资源系统包含一个地面水库供水系统、两个城镇市政供水系统、３个农区灌溉系统以及一个沼泽生态系统。它最早源于英国７０年代初所提出的灌溉系统对策仿真的设想，后经国外其他学者的不断完善，最后形成一种接近于现实的简单而综合的水资源系统管理原型，并以对策仿真的形式建立了其ＬＯＴＵＳ模拟模型。该对策仿真模拟模型中的对策者是地面水源管理者（ＷＡＭ）、市政供水管理者（ＰＷＳＭ）以及三组不同农户（ＦＡＲＭＥＲＳ）。为了使该系统更趋完善且更符合我国国情，本文又另外引入了一个称之为系统总管的对策者（ＭＡＮＡＧＥＲ）。他主要负责该系统的全面运行，解决系统中各对策者之间的矛盾冲突，监控全系统的环境质量，尽可能使整个系统获得最佳的社会、经济与环境效益。这种对策仿真模拟模型的主要目的是培养参加对策仿真的各位对策者，或者说水资源系统中的有关各方，即不同角色，更加熟悉一般水资源系统运行与管理过程中的各个方面。本文利用应用于微机的ＶＰ－专家系统外壳建立了这种对策仿     

电动软轴式玻璃升降器导轨的设计及成形工艺研究

介绍了电动软轴式玻璃升降器的工作原理。针对某种轿车的玻璃升降器 ,介绍了升降器的机构约束方法 ,并用UGII软件对其运动过程进行了仿真 ,确定了玻璃升降器螺旋导轨的曲率及螺旋导程。由于螺旋导轨成形极其困难 ,对导轨的形状进行修改 ,将螺旋形导轨改为扭转的圆弧导轨。介绍了扭转圆弧导轨的几种成形方法     

虚拟现实技术在环境管理中的应用

简介虚拟现实技术的发展及其应用概况，对虚拟现实技术应用于环境管理的可行性及优越性进行了分析，并从区域环境规划、环境治理、环境决策、环境预测、环境数学与科研等方面对具体的应用进行了探讨。     

汽油泄漏的池火灾危害特性及安全间距研究

针对油料泄漏引起池火灾的危害特性,重点研究池火灾热辐射作用范围的影响因素以及油料储存设备设施的安全间距问题。通过对汽油泄漏池火灾的燃烧特性参数进行分析,重点研究了油池直径对安全间距的影响,并结合具体案例对汽油池火灾的热辐射危害范围进行了经验估算和CFD仿真模拟分析。结果表明:当油池直径从10 m增加到40 m时,热辐射通量增大了11倍;当油池直径大于40 m后,热辐射通量随油池直径的增加以0.25倍的速率稳定增长;案例火灾发生时,救援人员应在距离火源220 m以外的区域展开救援。该研究结果可为油料泄漏引发的池火灾事故救援提供参考。     

滇池流域水污染控制仿真系统研究

阐述了滇池流域水污染控制仿真系统开发目标。根据系统对各用户的服务功能将系统的构件分为3个层面，建立了流域非点源模拟模型、流域水资源模拟模型及湖泊水动力和污染生态动力学模型。     

连续包覆型腔内应力应变分布的三维有限元分析

连续包覆型腔几何形状复杂,材料在型腔内为三维变形过程,利用一般的解析方法很难得到型腔内的应力应变分布规律,采用有限元法对连续包覆型腔内材料的变形状态进行了分析,得出了型腔内的三维应力、应变分布,为包覆型腔的优化设计提高了理论依据。     

A simulation analysis of the migration and transformation of pollutants contained in landfill leachate

A dynamic composite model for a soil-water system that can be used to simulate the movement of leachate from a landfill. The composite model includes nine sub-models that trace water movement and the migration and transformation of five pollutants(organic N, NE4^- ,NO3^- , NO2^-, and Cl^ - ) in saturated and unsaturated soil. The model to simulate the movement of leachate from a landfill in Laogang Town,Shanghai City was used. In this application, the values for the model parameters were oblained by performing a laboratory simulation experimentof water movement and pollutant migration and transformation in soil columns. Soil and leachate obtained from the landfill site and its vicinitywere used in the laboratory experiments. The model was then used to simulate leachate movement and pollutant activity during the ten-year period when the landfill was in operation and in the twenty-year period following its closure. The simulation results revealed that the leachate migrated into the groundwater at the rate of 90-100 meters per year. This model can be applied in the design of future landfills in China for the purpose of assessing and forecasting leachate plumes.     

板料激光弯曲成形及其数值模拟

介绍了一种利用激光扫描板料时形成的不均匀温度场所诱发的热应力进行弯曲变形的技术。采用非耦合模型,用有限元法对成形过程中的三维瞬态温度场及形变场进行了数值模拟,定量地解释了板料激光弯曲的变形机理。文中还介绍了动态边界热流的引入方法及改进热弹塑有限元计算精度和收敛性的措施。模拟值与实测值吻合。     

Simulation of temporal and spatial change of N2O emissions in the Yangtze River Delta

A biogeochemical model(DNDC) is combined with a plant ecological model to estimate N2O emission from rice paddy fields in the Yangtze River Delta region. The model is driven by local meteorological, soil, and physiological data and is validated for 1999 and 2000 at a site in the region, which showed that the simulated N2O emissions agree fairly well with the observed data. This adds some confidence in the estimated N2O emissions during 1950 and 2000 in the Hangzhou Region. A significant correlation between the N2O emissions and the population for the Hangzhou Region is found, which is due to a combination of increased application of fertilizers and cultivated area.Such a correlation can not be established for the whole Yangtze River Delta region when the data of both urban and rural are as areincluded. However, when the data from the heavily urbanized areas are excluded, a significant correlation between population and N2O emissions emerges. The results show clearly that both the temporal and the spatial N2O emissions have significant positive relationship with population under traditional farming practice. These results have implications for suitable mitigation options towards a sustainable agriculture and environment in this region.