PFC控制技术的一种改进方案

文章首先指出了目前ＰＦＣ所用控制技术的缺陷，然后提出了一各改进方案，并从理论分析和仿真验证的角度证明了改进方案的可行性和先进性。     

齿轮系统噪声预估及声诊断方法研究

通过对正常齿轮系统和故障齿轮系统振动信号的试验测试,提取了正常与故障齿轮的信号特征,以声学理论为基础,在系统运转的情况下分别在时域和频域对系统振动所产生的声压进行了模拟计算,并对正常情况、齿根裂纹故障情况(深度为3mm和5mm)、分度圆裂纹故障(深度为2mm和4mm)及齿面磨损情况下齿轮系统的辐射声压进行了比较分析,并与试验结果进行了对比验证。结果表明,利用声诊断方法不仅可以较好地对几种典型故障(类型,大小)进行初步定征和识别,在故障诊断领域有良好的应用前景,而且可以降低声压级测量的成本,有效避免环境噪声的影响。     

家具与“空间”的关系对家具设计的启示

家具和室内环境有着不可分割的关联性,彼此相互影响。本文从对室内设计的"空间"理论出发,着重分析空间理论中"空"的概念在家具中的表现,以及家具设计与空间环境之间的关系,并从柔性设计、美感等方面浅析"空间"理论对家具设计的启示。     

Biocontrol of postharvest gray and blue mold decay of apples with Rhodotorula mucilaginosa and possible mechanisms of action

The efficacy of Rhodotorula mucilaginosa against postharvest gray mold, blue mold and natural decay development of apples and the possible mechanisms involved were investigated. The decay incidence and lesion diameter of gray mold and blue mold of apples treated by R. mucilaginosa were significantly reduced compared with the control fruits, and the higher concentration of R. mucilaginosa, the better the efficacy of the biocontrol. R. mucilaginosa also significantly reduced the natural decay development of apples following storage at 20 °C for 35 days or at 4 °C for 45 days followed by 20 °C for 15 days. Germination and survival of spores of Penicillium expansum and Botrytis cinerea were markedly inhibited by R. mucilaginosa in an in vitro test. Rapid colonization of the yeast in apple wounds was observed whether stored at 20 °C or 4 °C. In apples, the activities of peroxidase (POD) and polyphenoloxidase (PPO) were significantly induced and lipid peroxidation (malondialdehyde (MDA) content) was highly inhibited by R. mucilaginosa treatment compared with those of the control fruits. All these results indicated that R. mucilaginosa has great potential for development of commercial formulations to control postharvest pathogens on fruits. Its modes of action were based on competition for space and nutrients with pathogens, inducement of activities of defense-related enzymes such as POD, PPO and inhibition of lipid peroxidation (MDA content) of apples, so as to enhance the resistance and delay the ripening and senescence of apples.     

汽车内衬零件复杂多工位连续模设计

汽车内衬零件的形状结构复杂、表面质量要求高、成形轮廓尺寸大,针对其成形过程中易出现滑移、回弹、起皱、拉裂等缺陷的问题,详细地分析了某款汽车内衬零件的冲压工艺性能,制定了包括冲孔、拉深、压凸包、翻边和弯曲等14个工位的成形工艺方案.为避免后期现场模具调试反复进行,在冲压工艺设计的前期,选择CAE分析软件对成形过程和质量缺...     

强威粉在天然橡胶汽车减震衬套胶料中的应用研究

研究强威粉在天然橡胶(NR)汽车减震衬套胶料中的应用。结果表明:强威粉属于纳米填料,与普通无机填料相比,强威粉对丁苯橡胶(SBR)基本配方胶料的补强性能较好,强威粉增量替代炭黑N770用于NR汽车减震衬套胶料中,胶料具有优异的强度性能、绝缘性能和减震性能,且原材料成本较低。强威粉适合用作减震和绝缘橡胶制品的填料。     

基于时频分布的齿轮系统辨识研究

采用时频分布方法在时频域对系统的非线性时变特性进行研究,识别了系统的动态固有特性,并与ARMA法和Hibert法进行比较,表明该方法是一种有效的齿轮系统辨识新方法。     

消声器法兰冲压工艺及翻孔翻边复合模设计

以汽车消声器法兰为研究对象,分析了零件冲压加工的最佳工艺方案.并根据零件形状设计了排样图,提出了零件翻孔翻边复合模的设计方法,阐述了模具工作过程和设计要点.实际生产表明:模具设计合理、实用.     

旋振筛的动力学分析及物料输送规律研究

对旋振筛进行动力学和运动学分析，得出振筛筛面空间运动轨迹是一条椭圆曲线，并对筛面上物料运动情况进行了研究，得到物料运动轨迹近似于一条螺线。通过实验测试验证了理论分析与实验结果的一致性。     

嵌段及接枝共聚物相容剂的研究与应用进展

重点介绍了嵌段及接枝共聚物相容剂的作用原理,综述了近年来我国嵌段及接枝共聚物相容剂的最新研究现状,最后指出了我国嵌段及接枝共聚物相容剂的发展方向。