Experimental investigation on chilled cast iron tappet manufacturing processes parameters

Chilled cast iron tappet has a tendency microstructure of white, mottled and gray iron. The exact composition and other casting parameters, like pouring temperature, inoculation and coating, need to be determined for achieving the desired thickness of the chilled layer. Chilled cast iron finds applications in areas where improved hardness and wear resistance are required. Mottled cast iron has very poor machinability and high brittleness due to the presence of secondary cementite. These constitute the limitations for its use. The influence of inoculation, pouring temperature, coating thickness and chill plate on chilled depth was investigated. Taguchi design-of-experiments (DOE) are used for generating an optimal set of casting parameters to obtain a satisfactory chilled depth. Analysis of the effects of all the parameters on chilled depth has been carried out through a microstructure study.     

基于数字图像处理的印刷墨斑分析方法及应用研究

针对印刷品常遇到的墨斑问题,利用数字图像处理技术分析印刷墨斑,建立了印品墨斑的分析方法及分析模型。在此基础之上,将该方法应用到喷墨纸、新闻纸、铜版纸、双胶纸上,并对四种纸张的印刷墨斑进行分析,同时将该方法与人眼视觉评价体系进行相关性分析。结果表明:本文构建印刷墨斑的数学模型及方法很好地分析了印刷品的墨斑,并与人眼视觉评价结果有很好的相关性,其中,喷墨纸运用此方法效果最佳。     

基于小波细节能量的印刷墨斑评价方法及应用

目的针对印刷墨斑的评价和测量,构建基于小波细节能量的印刷墨斑评价方法及模型。方法以铜版纸印刷品的印刷墨斑为例,利用图像小波去噪后的细节能量求和作为印刷墨斑的评价指标,与人眼视觉评价体系做相关性分析,对比两者的评价结果。结果构建的小波细节能量墨斑模型比传统COV模型具有较高的精确度。传统模型的相关系数为0.2009,经小波细节能量处理后的相关系数最小为0.5256,相关系数得到明显提高。结论小波细节能量模型能够作为一种有效的方法代替人眼视觉进行印刷墨斑的评价与分析。     

纸张转印墨斑检测方法初探

利用IGT印刷适性仪,在不同印刷条件下探讨了新闻纸、单面涂布白纸板和铜版纸转印墨斑的变化规律.结果表明,两种新闻纸的优化印刷条件为:油墨量0.10 mL、印刷压力650 N、速度0.4 m/s;主客观判定结果有差异,最少墨量时客观判定效果好,中等墨量时主观判定效果较好.两种涂布白纸板的优化印刷条件为:油墨量0.35mL、印刷压力200 N、速度0.3 m/s;铜版纸优选出的印刷条件为:油墨量0.50 mL,印刷压力500 N,速度0.2m/s.2人组及4人组主观判定结果的相关性较强;3种客观判定方法中,光谱法与主观判定的一致性最好,PTS法次之,灰度法最差,光谱法和PTS法有望作为评价纸张转印墨斑的新方法.     

Polycistronic Artificial microRNA-Mediated Resistance to Cucumber Green Mottle Mosaic Virus in Cucumber

Cucumber green mottle mosaic virus (CGMMV), as a typical seed-borne virus, causes costly and devastating diseases in the vegetable trade worldwide. Genetic sources for resistance to CGMMV in cucurbits are limited, and environmentally safe approaches for curbing the accumulation and spread of seed-transmitted viruses and cultivating completely resistant plants are needed. Here, we describe the design and application of RNA interference-based technologies, containing artificial microRNA (amiRNA) and synthetic trans-acting small interfering RNA (syn-tasiRNA), against conserved regions of different strains of the CGMMV genome. We used a rapid transient sensor system to identify effective anti-CGMMV amiRNAs. A virus seed transmission assay was developed, showing that the externally added polycistronic amiRNA and syn-tasiRNA can successfully block the accumulation of CGMMV in cucumber, but different virulent strains exhibited distinct influences on the expression of amiRNA due to the activity of the RNA-silencing suppressor. We also established stable transgenic cucumber plants expressing polycistronic amiRNA, which conferred disease resistance against CGMMV, and no sequence mutation was observed in CGMMV. This study demonstrates that RNA interference-based technologies can effectively prevent the occurrence and accumulation of CGMMV. The results provide a basis to establish and fine-tune approaches to prevent and treat seed-based transmission viral infections.     

In-Plane Ordering of a Genetically Engineered Viral Protein Cage

Protein cages architectures can be used as nanoscale building blocks to fabricate higher order structures. We show here that in-plane ordering can be induced in films of a genetically engineered viral protein cage bound electrostatically to a planar surface. Surface pressure measurements were used to follow the kinetics of adsorption of the virus nanoparticle at the air-water interface for a range of sucrose and nanoparticle subphase concentrations. Atomic force microscope (AFM) images indicated that with optimal subphase conditions films transferred to solid supports exhibited regions of hexagonal packed 2-D arrays. Potential applications of these monolayer assemblies of protein cage architectures include their use as scaffolds to immobilize functional groups at a surface or as templates for building multilayer films.     

Quantification of banding on printed corrugated board using spatial frequency analysis

The human visual system has an exceptional ability to detect systematic print mottle. One type of systematic print mottle is banding on printed corrugated board, resulting in a disturbing print defect. A new method that quantifies banding on printed corrugated board is proposed. The method is based on spatial frequency analysis, and the degree of banding is determined using a band‐pass filter range adapted to fit the flute wavelength and orientation of the acquired image of the printed board. The results for B‐flute corrugated board gave a correlation coefficient of 0.98 between the technical measurements and the subjective ratings. Methods of quantifying the banding on the different types of corrugated board available on the market are discussed. Copyright © 2005 John Wiley & Sons, Ltd.     

多元复杂黄铜表面变色斑点初探

本文对多元复杂黄铜管材锻压前圈料表面变色斑点进行了研究。分析表明,变色斑点现象的出现与材料中夹杂（或夹渣）物的存在有必然联系。在复杂黄铜熔炼过程中采取措施控制铸锭或铸管夹杂（或夹渣）对提高黄铜管材质量具有重要作用。     

永磁铁氧体“花斑”现象的研究

以铁鳞作为原料是永磁铁氧体预烧料生产经常采用的方法，在永磁铁氧体产品的生产过程中，经常会遇到所谓的跑锶和“花斑”现象，严重影响产品的外观。本文阐述了永磁铁氧体跑锶和“花斑”现象产生的原因和形成机理，并采取有效的预烧工艺控制和二次添加技术，很好地解决了压坯和烧结体的“花斑”与水印现象。     

甘薯羽状斑驳病毒和甘薯褪绿矮化病毒复合侵染甘薯引起的细胞病理学研究

2011～2012年在浙江杭州连续发现感病甘薯植株具有甘薯病毒病SPVD的典型症状,透射电镜观察发现其叶片包含有长度为600—900nm,直径为12nm的线状病毒粒子。使用特异性引物进行RT—PCR扩增及测序,其病原为甘薯羽状癍驳病毒（Sweet potato feathery mottle virus,SPFMV）和甘薯褪绿矮化病毒（Sweet potato chlorotic stunt virus,SPCSV）复合侵染。运用透射电镜研究SPVD引起的细胞病理学变化,观察到叶肉细胞的细胞质中含有马铃薯Y病毒属特征性柱状内含体,其结构分类为Ⅳ型;线状病毒样粒子以束状平行排列成聚集体的方式存在于细胞质中;叶绿体伸出伪足状结构包裹线粒体。在维管束细胞的筛管和伴胞中观察到弯曲线状病毒样粒子形成的聚集体,其粒子排列交错,与叶肉细胞中平行排列的病毒样粒子聚集体不同,符合毛形病毒属特征。另外还在维管束和叶肉细胞结合的部位发现复合侵染的细胞病理学特征。本研究表明危害甘薯生产的SPVD已扩散蔓延到浙江省。