汽车天棚控制半主动悬架模型仿真与性能分析

该文对比研究了天棚控制半主动悬架的动力学性能。在建立线性被动悬架、传统非线性弹簧悬架和天棚控制半主动悬架动力学模型的基础上。利用MATLAB软件的SIMULINK工具箱对其进行仿真,获得车身加速度时域频域响应特性、轮胎动载荷及悬架动挠度的时域特性,并对仿真结果进行了对比分析。天棚控制半主动悬架的阻尼系数通过估算确定。结果表明。半主动悬架有效地改善了汽车的行驶平顺性和操纵稳定性,但其在衰减高频振动上仍存在不足。     

通过注册表监控实现木马检测

提出一种基于挂接系统服务的木马检测技术,通过对注册表进行实时监控,有效地实现了对已知和未知木马的检测。传统的基于特征码的检测技术,只能检测已知的特洛伊木马,基于挂接系统服务的技术,有效克服了上述缺陷,试验结果证明了其有效性和准确性。     

利用核心态钩挂技术防止代码注入攻击

为防止代码注入攻击,利用钩挂技术来监视有关的API函数调用十分必要。由于Windows NT系统中存在着严格的进程隔离机制,此种钩挂要在核心态下才有效。提出并讨论了实现此种技术的一种简便的方法。实践表明,在Windows XP系统条件下,利用它能够成功阻止木马利用代码注入实现攻击。     

Dynamic Changes in Reactive Oxygen Species in the Shoot Apex Contribute to Stem Cell Death in Arabidopsis thaliana

In monocarpic plants, stem cells are fated to die. However, the potential mechanism of stem cell death has remained elusive. Here, we reveal that the levels of two forms of reactive oxygen species (ROS), superoxide anion free radical (O2·−) and hydrogen peroxide (H₂O₂), show dynamic changes in the shoot apex during the plant life cycle of Arabidopsis thaliana. We found that the level of O2·− decreased and disappeared at four weeks after bolting (WAB), while H₂O₂ appeared at 3 WAB and showed a burst at 5 WAB. The timing of dynamic changes in O2·− and H₂O₂ was delayed for approximately three weeks in clv3-2, which has a longer lifespan. Moreover, exogenous application of H₂O₂ inhibited the expression of the stem cell determinant WUSCHEL (WUS) and promoted the expression of the developmentally programmed cell death (dPCD) marker gene ORESARA 1 (ORE1). These results indicate that H₂O₂ triggers an important signal inducing dPCD in stem cells. Given that O2·− plays roles in maintaining WUS expression and stem cell activity, we speculate that the dynamic shift from O2·− to H₂O₂ in the shoot apex results in stem cell death. Our findings provide novel insights for understanding ROS-mediated regulation during plant stem cell death.     

汽油在线优化调合系统在长岭石化的应用

长岭石化2011年原油实际加工能力达到1000×104t/a.引进霍尼韦尔油品调合技术和近红外在线检测技术,实施汽油在线优化调合项目.汽油在线调合技术方案是以调合规则(也称调合属性预测模型)为基础的多变量预测优化调合控制,结合在线分析仪提供的质量反馈校正,实现以成品油质量为控制目标的在线管道优化调合技术,包括调合优化控制(Open BPC)软件和调合比例控制(BRC)软件.该系统在保证成品汽油质量合格的前提下,平均调合完成一罐(5000m3)的时间由原来的2.5d缩短至1.5d;应用优化调合系统,用3.5×104m3的库容实现了8000m3/d的调合交库任务;93号和97号成品汽油的研究法辛烷值(RON)平均分别降低0.4和0.3个单位,减少了质量过剩,一次调合合格率由70％升至95％以上.2011年长岭石化汽油产量为135.5×104t,少添加MMT36.88t,节省费用686万元.     

七支点电动双轨悬挂起重机

介绍了七支点电动双轨悬挂起重机的主要技术参数及主要零部件设计,指出了该机的关键技术问题.该机的成功研制填补了我国起重设备在该领域的空白,为同类产品的设计提供经验.     

Friction stir scribe welding technique for dissimilar joining of aluminium and galvanised steel

Friction stir scribe technology, a derivative of friction stir welding, was applied for the dissimilar lap welding of an aluminium alloy and galvanised mild steel sheets. During the process, the rotating tool with a cobalt steel scribe first penetrated the top material – aluminium – and then the scribe cuts the bottom material – steel. The steel was displaced into the upper material to produce a characteristic hook feature. Lap welds were shear tested, and their fracture paths were studied. Welding parameters affected the welding features, including hook height, which turned out to be highly related to fracture position. Therefore, in this paper, the relationships among welding parameters, hook height, joint strength and fracture position are presented. In addition, the influence of zinc coating on joint strength was also studied.     

楔面动力卡盘夹紧效率特性研究

对楔面动力卡盘的夹紧效率特性进行了理论分析和实验研究,建立了楔面动力卡盘夹紧效率的数学模型,研究了夹紧传动机构摩擦系数、楔面角度、卡盘工作参数以及连续重复夹紧次数等参数对夹紧效率的影响规律,对卡盘的优化设计和应用以及夹紧力计算具有指导意义。     

天车自动控制系统主起升输出双通道保护

炼钢工序180 t遥控天车主要承担钢水罐的吊运和转炉兑铁水的任务。由于环境恶劣,加速了PLC模块和继电器的老化,导致PLC模块输出通道粘连、通道烧坏,主钩上极限保护失效、总电源无法停止复位等故障,引发过主副钩起升自动升降、溜钩等现象,给安全生产造成了极大的隐患。本文通过天车主起升的保护功能的可靠性、可行性进行综合分析,论证PLC双通道输出对天车主起升的保护作用。