Improved preprocessed Yaroslavsky filter based on shearlet features

An improved preprocessed Yaroslavsky filter (IPYF) is proposed to avoid the nick effects and obtain a better denoising result when the noise variance is unknown. Different from its predecessors, the similarity between two pixels is calculated by shearlet features. The feature vector consists of initial denoised results by the non-subsampled shearlet transform hard thresholding (NSST-HT) and NSST coefficients, which can help allocate the averaging weights more reasonably. With the correct estimated noise variance, the NSST-HT can provide good denoised results as the initial estimation and high-frequency coefficients contribute large weights to preserve textures. In case of the incorrect estimated noise variance, the low-frequency coefficients will mitigate the nick effect in cartoon regions greatly, making the IPYF more robust than the original PYF. Detailed experimental results show that the IPYF is a very competitive method based on a comprehensive consideration involving peak signal to noise ratio (PSNR), computing time, visual quality and method noise.     

镍基合金+WC激光熔覆层的显微组织形成机理及控制

采用光学显微镜、X射线衍射仪、扫描电子显微镜、能谱分析等手段对镍基合金+WC熔覆粉末颗粒的颗粒种类、颗粒粒径、不同种类颗粒的分布及镍基合金+WC激光熔覆层内各种组织的不均匀分布进行了研究。根据热平衡原理建立了熔覆材料颗粒半径、激光束功率密度和熔覆材料颗粒加热温度之间的定量关系式,提出通过控制各种熔覆材料颗粒大小来实现设计与控制送粉激光熔覆层的显微组织,并以WC与N i基自熔合金混合粉料为熔覆材料,对获得的熔覆层的显微组织进行分析,证明了所提出的熔覆层显微组织的设计与控制方法的可行性与实用性。     

冷连轧带材表面划痕研究

随着机械工业和国民经济各部门生产的发展和技术进步,对钢材产品质量的要求越来越高。对于冷连轧机高速生产过程中的划痕问题,文章在引入划痕综合判断标准新概念的基础上,探讨了划痕产生的机理,并分析了轧制速度、压下规程、张力制度、工作辊粗糙度等因素对划痕的影响,对于指导生产实践,治理划痕,提高产品质量,具有重要的实际意义。     

板坯加热炉出钢滑坡结构的优化设计

板坯加热炉中合理的出炉滑坡结构对减少钢坯划伤、配合炉门密封、减少钢坯对炉门及出炉辊道的冲击力都很重要。对中板厂滑坡结构的优化设计作了分析。     

750mm连续光亮退火线张力机的改进

本文介绍了用分散的静摩擦替代原来整体的滑动摩擦，解决传统摩擦方式建立张力易出现质量问题的张力机改进方法。     

便携式圆钢划痕在线检测仪

轧钢过程中,圆钢由于轧辊毛刺或其他固态颗粒通常会引起较长的划痕,造成极大的损失.针对这种情况,基于光纤反射原理,设计了一种便携式的划痕高温在线检测仪.检测仪通过2路光路反射信号的强度之差是否超过预定的阈值,来自动判断划痕是否存在,从而实现了划痕在高温下的在线检测.介绍了系统的构成框图、差分工作原理,光源驱动电路、光敏二极管接收电路以及单片机电路,并简要介绍了软件流程图.该系统体积小,重量轻,使用方便,具有较高的经济价值.     

16MnR钢换热器壳体开裂分析

采用光学金相显微镜、扫描电镜等测试方法对运行不足10个月即发生开裂的16MnR钢换热器壳体进行了分析。结果表明，换热器壳体开裂是由应力腐蚀造成的，内壁焊缝打磨处存在大量划痕以及残余应力是引起腐蚀开裂的主要因素。同时，焊接应力的存在和水质不良加速了裂纹的扩展。在分析的基础上提出了改进建议。     

电子产品生产中的临时性防护

分析了各种自然环境条件下的失效机理,较详细解释了电子设备临时性防护的主要途径,提出了注重质量意识、注重细节的质量观点。     

发动机引气管卡箍断裂原因分析

在发动机试车过程中,其引气管卡箍发生断裂。通过对该故障引气管卡箍进行外观检查、断口分析、表面微观检查、材质分析及卡箍应力分布计算,以确定引气管卡箍断裂性质及原因。结果表明:卡箍断裂性质为高周疲劳断裂,卡箍安装端折弯处转角较小与划痕所致的应力集中是导致卡箍过早发生疲劳断裂的主要原因,振动载荷也加速了该卡箍疲劳断裂故障发生;提出了在卡箍成型加工过程中避免划痕划伤基体及适当加大折弯处转角R的改进建议。     

Apoptotic pathways depend on the target enzymatic activity and not on the triggering agent

Molt-4 human leukemia cells were triggered to apoptosis by various agents with different mechanisms of action. Staurosporine, a protein kinase C (PKC) inhibitor; camptothecin, a topoisomerase I blocking drug; and tiazofurin, an inhibitor of inosine 5'-phosphate dehydrogenase (IMPDH), were used. Ultrastructural analysis showed morphologic changes characteristic of apoptosis that were very similar for all three agents. Nevertheless, DNA oligonucleosomic fragmentation was not detectable by agarose gel electrophoresis. However, a genomic DNA cleavage appeared after pulse-field gel electrophoresis (PFGE) in cells treated with these agents for 24 h. Furthermore, in situ nick translation (NT) showed a finely spotted nuclear labelling in staurosporine-treated cells and a compact fluorescence after camptothecin incubation. In tiazofurin-treated cells an intermediate pattern was found. Therefore, apoptotic agents with different mechanisms of action induced the formation of large genomic DNA fragments and very similar ultrastructural changes. Therefore, both phenomena and the closely related apoptosis progression depend on target cell machinery and not on the triggering agent.