兆河闸钢闸门安全复核

文章分析了兆河闸钢闸门存在的问题,对闸门的结构进行了安全复核:兆河闸钢闸门已不能安全运行。     

基于故障树与模糊理论的天然气门站安全评价

城市天然气门站安全状况的好坏,直接影响到整个城市天然气系统的安全运行,为此运用故障树分析法与模糊理论对城市天然气门站的安全状况进行了分析。通过对站内危险因素的分析,建立门站系统的失效故障树,得到引起天然气门站主要系统失效的28个主要事件,建立了门站安全评价指标体系。利用模糊综合评判理论对门站安全状况进行了定量分析,利用专家评分法对指标进行了评分,利用层次分析法计算了各指标层次相对权重;通过模糊理论得出门站安全等级,并给出了相应的日常安全工作重点。用该方法对常州市天然气门站进行安全评价,得出安全等级为Ⅱ级,这与门站实际运行状况相符,说明用该方法对门站进行安全评价是有效、可靠的,能够为城市天然气门站安全管理提供依据。     

通过原子和腔共振相互作用实现Bell门的方案

提出一个在腔QED中用两个三能级原子和单模腔共振的相互作用实现Bell门的方案.基于目前的腔QED技术本方案可以被实现.     

Tensile properties with or without heat dispersion of automotive needlepunched carpets made up of two layers of different materials

Tensile properties of automotive needlepunched carpets made up of two layers of different materials （a fabric layer and a foam layer） in their thermoforming temperatures ranges with or without heat dispersion were discussed. Effects of forming temperature, extensile speed and fiber orientation on the tensile properties were studied based on an orthogonal experiment design. The experimental results show that automotive carpets are rate-dependent anisotropic materials and more strongly depend on forming temperature than the extensile speed and fiber orientation. Furthermore, contributions of the fabric layer and the foam layer to the overall tensile performance were investigated by comparing the tensile results of single fabric layer with those of the overall carpet. Both the fabric layer and the foam layer show positive effects on the overall tensile strength which is the combination of the two layers＇ tensile strength and independent of temperature, extensile speed and fiber orientation On the other hand, their influences on the overall deformation are relatively complicated.     

Gate oxide punching thru mechanism in plasma dry etching

The punching thru mechanism of gate oxide (thickness about 15A) was investigated. Because of the thin thickness of gate oxide, gate oxide punching thru may easily happen during the plasma process. It was found that what caused the punching thru was not only the selectivity of poly-silicon/oxide but also the pattern topography. We used the basic SRAM pattern to check this topography effect, and found that gate oxide located at the narrow spacing of two parallel serpentine lines was the most easily punched thru. What caused the topography effect was the starvation of oxygen in these places which were induced by the residue of poly-silicon and enhanced by electron shading effect. So, to solve the issue of gate oxide punching thru, firstly the selectivity should be enough, secondly we should pay attention to the etching pattern topography. Supported by the National High-Tech Research and Development Program of China (“863” Project) (Grant No. 2006AA843134) and the National Basic Research Program of China ("973" Project) (Grant No. 2007CB935302)     

应用于等离子显示驱动的高压集成电路工艺

介绍了等离子显示板(PDP)扫描驱动集成电路(IC)的结构和工作原理,提出了一种与2.0 μm标准CMOS工艺完全兼容的新型高压BCD工艺.设计了新型场氧作厚栅HV pMOS器件和薄栅氧HV nVDMOS器件,开发了一种新型的PDP扫描驱动集成电路.采用此工艺可以节省三个光刻版、两次注入（HV N阱和PDA）和一次氧化工艺,有效地降低工艺复杂度和生产成本.最终流片和测试结果表明,HV nVDMOS和HV pMOS管的耐压均超过165 V,达到系统设计要求.当电源电压为90 V、负载为200 pF时,PDP扫描驱动芯片的上升沿和下降沿时间分别为165和30 ns,这充分验证了芯片具有很强的驱动电流能力     

汽车链发动机总成试验及磨损特性

通过汽车发动机总成试验,研究了汽车链的磨损机制和磨损伸长率,分析了销轴和套筒磨损表面的微观形貌和滚子材料的金相组织,探讨了汽车链主要零件的塑性变形和磨损表面的循环特性,并通过联结牢固度的压出力试验阐述了汽车链过盈配合表面的微动磨损现象及其原因。结果表明,销轴和套筒磨损表面的磨损机制以疲劳磨损为主,同时伴有磨粒磨损和粘着磨损;经过3000 h高速试验,链板和滚子产生了以往少见的较大塑性变形,滚子磨损表面产生了循环硬化,并且过盈配合表面产生了严重的微动磨损。     

不同强度侧风对轿车气动特性影响的瞬态数值模拟研究

为研究典型轿车在不同强度侧风影响下的气动特性,通过用户自定义函数实现计算网格的动态更新和侧面入口速度随时间的变化,动态模拟了汽车行驶通过一个侧风速度随时间不断增强的区域,对不同强度侧风下汽车的气动特性进行了瞬态数值模拟研究。研究结果表明,阻力、侧倾力矩和纵倾力矩受侧风影响不大,而升力、侧向力和横摆力矩受侧风的影响显著。随着侧风的增大,升力、侧向力和横摆力矩明显增大,严重影响了汽车的行驶稳定性。     

汽车小活塞硬质阳极氧化工艺的优化

采用自制的脉冲恒流电源装置,研究了汽车小活塞的脉冲恒流硬质阳极氧化工艺,通过改变工艺参数,得到了较佳工艺方案。结果表明:在槽液浓度为25%(质量比)、氧化温度为-10~-8℃、电流密度为3A/dm2、氧化90 m in的条件下制备出的硬质氧化膜组织致密,表面最大硬度可达558 HV,膜层厚度为70~90μm。该优化工艺较原工艺氧化时间少用30 m in,氧化膜厚度增加了20~50μm,氧化膜层硬度最大提高了256 HV。     

基于FPGA和LMD18200的步进电机控制系统

提出了一种控制步进电机的设计方法,结合MCU、FPGA和增量型编码器构成了一个完整的运动控制平台。系统由总线接口单元、闭环控制单元、PWM脉宽调制单元和LMD18200驱动单元组成。实践表明,利用LMD18200驱动逻辑能够使步进电机高效稳定地运行,有效降低了电机运行中的噪声和起动、停止时的振动,使用效果好于大部分常规步进电机驱动方法。