冷却槽对自孕育法制备ZA92镁合金组织的细化作用

采用自孕育法制备新型的ZA92镁合金,研究了冷却槽对组织的细化作用,并对其机理进行了分析。结果表明:合金熔体内部的形核与冷却槽的激冷作用、熔体的流动速度及剪切力的大小有关,合适的冷却槽角度有利于晶粒的游离和增殖。熔体在流经冷却槽的过程中,其组织变化趋势为:粗大枝晶→细小枝晶→等轴晶→蔷薇状晶和近球状晶。冷却槽角度较大或较小均不利于组织的细化,当冷却槽角度在30~45°之间时,坯料组织的晶粒分布比较集中且细小,其平均晶粒尺寸在47.5~51.4μm之间。     

渗碳钢变温渗碳过程分析

以２０ＣｒＭｎＴｉ钢为例,建立了连续冷却渗碳模型;对变温渗碳质量进行了分析计算;对渗碳后的组织情况进行预测,从而对变温渗碳的可行性进行了理论论证．     

浮盖式蓄水屋顶隔热功效研究

描述蓄水屋机的演变过程,推荐隔热效果最优化的浮盖式方案,提出蓄水屋顶动态襄减的新见解,分析影响衰减的主要因素。     

New GOES imager algorithms for cloud and active fire detection and fire radiative power assessment across North, South and Central America

Vegetation fires are a key global terrestrial disturbance factor and a major source of atmospheric trace gases and aerosols. Therefore, many earth-system science and operational monitoring applications require access to repetitive, frequent and well-characterized information on fire emissions source strengths. Geostationary imagers offer important temporal advantages when studying rapidly changing phenomena such as vegetation fires. Here we present a new algorithm for detecting and characterising active fires burning within the imager footprints of the Geostationary Operational Environmental Satellites (GOES), including consideration of cloud-cover and calculation of fire radiative power (FRP), a metric shown to be strongly related to fuel consumption and smoke emission rates. The approach is based on a set of algorithms now delivering near real time (NRT) operational FRP products from the Meteosat Spinning Enhanced Visible and Infra-Red Imager (SEVIRI) imager (available from http://landsaf.meteo.pt/), and the GOES processing chain presented here is designed to deliver a compatible fire product to complete geostationary coverage of the Western hemisphere. Results from the two GOES imagers are intercompared, and are independently verified against the well regarded MODIS cloud mask and active fire products. We find that the detection of cloud and active fires from GOES matches that of MODIS very well for fire pixels having FRP > 30 MW, when the GOES omission error falls to less than 10%. The FRP of fire clusters detected near simultaneously by both GOES and MODIS have a bias of only 22 MW, and a similar bias is found when comparing near-simultaneous GOES East and GOES West FRP observations. However, many fire pixels having FRP < 30 MW remain undetected by GOES, probably unavoidably since it has a much coarser spatial resolution than MODIS. Adjustment using data from the less frequent but more accurate views obtained from high spatial resolution polar orbiting imagers could be used to bias correct regional FRP totals. Temporal integration of the GOES FRP record indicates that during the summer months, biomass burning combusts thousands of millions of tonnes of fuel daily across the Americas. Comparison of these results to those of the Global Fire Emissions Database (GFEDv2) indicate strong linear relationships (r² > 0.9), suggesting that the timely FRP data available from a GOES real-time data feed is likely to be a suitable fire emissions source strength term for inclusion in schemes aiming to forecast the concentrations of atmospheric constituents affected by biomass burning.     

莱钢2号连铸机及热送热装的改造

分析了连铸机改造前和高效改造后新老系统在控制上的特点 ,着重介绍了改造后控制系统硬件和软件特点 ,该系统投运后不仅解决了本连铸机的自动控制 ,而且完成了连铸 热送 轧钢生产线的顺利贯通。     

模糊PID控制在冷却水温控系统中的应用

针对上海光源冷却水温控系统中板式换热器的时变特性和系统大滞后特性,结合PID控制和模糊控制的优点,提出了以误差和误差变化率为输入信号的Fuzzy-PID复合控制器和以误差和响应时间为输入信号的模式选择开关控制器来实现冷却水温度控制策略。仿真实验和实际应用表明,该控制策略能够克服板式换热器时变特性和系统大滞后特性,对负载发生变化后能以较短的响应时间和较小的超调量使系统达到新的平衡,控制效果优于传统的PID控制。     

热轧带钢层流冷却系统的前馈-反馈控制及其优化

以热轧层流冷却系统为研究对象,对如何提高带钢卷取温度控制精度进行了研究;在带钢冷却模型的基础上,对预设定模块进行了前馈补偿;考虑模型的不确定性和大时滞特性,采用模糊Smith预估器提高了反馈控制的精度;结果证明所采用的这些措施大大提高了卷取温度的控制精度。     

基于MATLAB的化工课程设计软件开发

在MATLAB平台上开发化工原理课程设计软件。本文以冷却塔设计为例介绍了该软件的主要内容结构和功能 ,它具有操作简单、使用方便、效率高、数值稳定性好等特点 ,使计算结果可视化     

有限元法求解无定形料挤出制品水浴冷却温度场

应用传热学和有限元基本原理，用线性三角形单元数值求解了无定形料挤出制品水浴冷却的瞬态温度场，进而可求得冷却时间，以及所需冷却水槽的长度。通过两个算例与解析解、ANSYS数值模拟结果的比较，说明了文中算法的可行性与合理性。     

ⅢJ-99轴径向内冷一绝热氨合成塔内件的应用

本文介绍了ⅢJ- 99合成塔内件在我厂原DN 80 0系统中的应用。阐述了该内件的结构特点和在实际生产中的优点 ,并讨论原系统影响内件潜力发挥的制约因素。