面包车尾部造型对其气动特性的影响

为了研究面包车气动特性的影响因素,以国产某小客车简化模型为研究对象,在对基础模型进行试验验证的基础上,通过数值模拟的方法,计算后风窗角度、背部角度和底部上翘角度改变以后面包车的气动阻力和升力,得到其变化规律,并把各种角度相互组合,得出最佳的尾部造型.模拟结果表明:上述3种因素对面包车的气动特性均有很大的影响,在设计过程...     

嵌入式Linux下的FRAM驱动程序设计

针对铁电存储器(FRAM)在基于ARM9的嵌入式Linux系统下设备节点的读写及应用问题,研究Linux系统的驱动设计,分析FRAM的工作原理和硬件特性,提出基于Linux系统标准驱动架构与铁电底层预处理、读写、控制等工作机制相结合的FRAM驱动程序设计与实现流程。底层实现采用内核级基于FRAM的寻址方式,结果证明了该驱动在相应数据存储、传输中的可行性与稳定性。     

匹配二级顺序增压系统的柴油机高原特性仿真

为了满足柴油机在海拔0～5500 m内功率输出要求,提出了二级顺序增压系统的方案.针对CA6DL2柴油机,根据高原功率恢复指标计算确定了增压系统参数并进行了低压级增压器的选型.利用循环模拟软件GT-Power进行了柴油机高原特性仿真计算.结果表明:发动机与二级顺序增压系统匹配良好,在保持平原输出功率不变的同时,海拔5 ...     

新型卡车CAN/LIN电气系统网络的研究

随着电子技术的高速发展和广泛应用,实现汽车电子化、智能化和网络化是现代汽车发展的必然趋势。根据某新型卡车的实际需求,研究并构建了CAN／LIN总线的卡车电气系统网络。在简要介绍了电气系统网络的组成与功能之后,分析了CAN、LIN总线的特点,并根据卡车的实际需求制定了相应的应用协议,最后给出了网络系统软硬件设计的具体方案。实际应用和测试结果表明,本系统具有良好的可靠性和稳定性。     

基于流角色检测P2P botnet

提出了一种基于流角色的实时检测P2P botnet的模型,该模型从流本身的特性出发,使其在检测P2P botnet时处于不同的角色,以发现P2P botnet的本质异常和攻击异常,同时考虑到了网络应用程序对检测的影响。为进一步提高检测精度,提出了一种基于滑动窗口的实时估算Hurst指数的方法,并采用Kaufman算法来动态调整阈值。实验表明,该模型能有效检测新型P2P botnet。     

DSC investigation of high-temperature aging of an Al-Mg 10 at% alloy

The characteristics of the aging process of a high-purity Al-Mg 10 at% alloy at 150°C were investigated by differential scanning calorimetry (DSC). Two transitions were detected after several days of aging and assigned to β' platelets and β rods. An effect of precipitation and dissolution of Guinier-Preston zones was detected too during DSC runs. DSC results were compared with transmission electron microscopy analysis.     

铌硼微合金化齿轮钢的晶粒尺寸及淬透性

研究了Nb-B微合金化20CrMoH渗碳齿轮钢的奥氏体晶粒长大规律及微合金化对其淬透性的影响。结果表明,添加0.04%Nb可以有效地细化奥氏体晶粒,并且在1050℃奥氏体化10h无混晶现象。此外,添加0.0008%B能够明显提高钢的淬透性,使淬透性不因晶粒细化及Nb(C,N)析出而降低。     

Effects of ambient temperature on firing behavior and unregulated emissions of spark-ignition methanol and liquefied petroleum gas/methanol engines during cold start

The effects of the ambient temperature on the firing behavior and the unregulated emissions (formaldehyde and unburned methanol emissions) of electronically controlled inlet port injection spark-ignition methanol and liquefied petroleum gas (LPG)/methanol engines during the cold start were investigated experimentally by means of a single-cycle fuel injection strategy. The test results indicated that the minimum amount of methanol injected per cycle to ensure the methanol engine reliable firing increases 86% with the reduction of the ambient temperature from 301 to 289 K. With the ambient temperature below 289 K, the methanol engine cannot be started reliably without the other assistant measures even with a large methanol injection. The LPG only played a part of start-aids in the LPG/methanol engine. Using additional LPG injected into the inlet port results in a reliable firing of the LPG/methanol engine at low ambient temperature during cold start. When the ambient temperature drops, the mass ratio of injected LPG/methanol for the reliable firing of the LPG/methanol engine during cold start increases rapidly. The maximum combustion pressure in the cylinder, the maximum instantaneous engine speed, and the formaldehyde emissions increase significantly and the unburned methanol decreases obviously with the rise of the ambient temperature.     

汽车涂装节能减排的新工艺技术

在介绍21世纪汽车涂装主题和汽车涂装能耗现状及国内外差距的基础上,推荐了2项成熟的、已获得工业应用的节能减排新工艺技术及管理经验,并为创建环境友好型、低碳经济型社会建言献策。     

我国汽车涂装与汽车涂料的现况及发展趋势(三)——创建绿色涂装车间

介绍我国汽车涂装与汽车涂料工业现况,谈了对绿色涂装概念的理解,推荐在进入21世纪以来获得工业应用的、革命性的10大绿色技术创新,并为创建环境友好型、低碳经济型社会建言献策。