染料影像重氮盐感光纸制备的研究

(续2002年第1期) 4 重氮盐感光纸性能的检测 4.1 感光速度 关于重氮感光纸的感光速度,一般是采用“阶梯法”,其误差较大。为了与日本理光高速重氮感光纸进行比较,我们采用了美国和日本的重氮感光纸测定标准(JIS P4505,1979)。用印相速度来对重氮感光纸的感光速度作相对比较。用下列公式计算:

高校照片档案的管理

照片档案是高校声像档案的重要组成部分,它数量多,历史久远,反映的内容涉及面广且丰富多彩,形成部门及人员多而不固定。

凹印技术新进展

Drupa 2004上,展示了许多凹印新技术,其中有一些属于凹印版滚筒制备领域.凹印版滚筒制备有3种技术:一是基于金刚石雕刻头的雕刻系统来自HellGravure与MDC Max Daetwyler,使用较久;二是Daetwyler的滚筒直接激光雕刻技术和Hell的新型激光雕刻解决方案;三是基于感光涂层激光成像与化学处理相结合的混合制备技术.Drupa 2004上展出的主要是第三种.

核-壳型聚合物乳液对照像性能的促进和稳定作用

人工合成聚合物被广泛应用于卤化银感光材料 ,改善其物理力学性能。经过试验发现 ,特殊设计 ,合成的核—壳型聚合物乳液用于卤化银感光材料涂层中 ,不仅能提高胶片的物理力学性能 ,对照像性能也能产生促进和稳定作用 ;在胶片的人工老化过程中 ,对照像性能 ,尤其是反差和感光度的衰退起到明显的抑制作用 ,特别适用于高感、高反差印刷制版胶片。在大量应用试验的基础上 。

Effect of Fe content on microstructure and mechanical properties of Cu-Fe-based composite coatings by laser induction hybrid rapid cladding

To select the proper composition and obtain an overall material?microstructure?property relationship for Cu?Fe alloy, theeffect of Fe content on microstructure and properties of Cu?Fe-based composite coatings by laser induction hybrid rapid claddingwas investigated. Microstructure characterization of the composite coatings was tested utilizing SEM, XRD and EDS. Microhardnessmeasurement was executed to evaluate the mechanical properties of the composite coatings. The results show that for low Fe content,the composite coating presents a feature that Fe-rich equiaxed dendrites are embedded in the Cu-rich matrix. With increasing Fecontent, the Fe-rich particles are dispersed in the Cu-rich matrix. With further increasing Fe content, large amounts of Cu-richparticles are homogeneously dispersed in the interdendrite of the Fe-rich matrix. Correspondingly, the average microhardness of thecomposite coatings increases gradually with the increase of Fe content and the microhardness of Cu14.5Fe83Si2C0.5 coating is muchtwice higher than that of the substrate.

One-step synthesis of fluorescent hydroxyls-coated carbon dots with hydrothermal reaction and its application to optical sensing of metal ions

Carbon dots (CDs) with average diameter of 3.1 ± 0.5 nm were facilely synthesized with candle soot through hydrothermal reaction in sodium hydroxide aqueous solution. The as-prepared CDs were covered with a lot of hydroxyls, possessed properties of good water-solubility, anti-photobleaching, salt tolerance, and low cytotoxicity, and had a fluorescence quantum yield (QY) of about 5.5%. The fluorescence of the hydroxyls-coated CDs could be selectively quenched by metal ions such as Cr3+, Al3+ and Fe3+, which is because these metals can easily combine with the hydroxyl groups on the surface of CDs and induce aggregation of hydroxyls-coated CDs. Experiments showed that the quenching of Cr3+ had a Sterm-Volmer constant of 1.03 × 107 M-1 with a liner range of 1.0-25.0 μM and detection limit of 60 nM (3σ).

Design of high-sensitivity metal-coated LPFG sensor based on material dispersion

A high-sensitivity metal-coated long-period fiber grating(LPFG) sensor based on material dispersion is designed.Based on the coupled mode theory,the influence of the material dispersion on the dual-peak characteristics of the metal-coated LPFG is studied.After considering the material dispersion,the jumping region of the dual-resonant-wavelength shifts toward the thinner film thickness,and the sensitivity of the dual-peak metal-coated LPFG sensor to liquid refractive index(RI) can be obtained to supply accurate parameter combinations.Experimentally,two kinds of silver-coated LPFGs with different film thicknesses and grating periods are fabricated to monitor the salt solution,and the sensitivities of these two sensors are compared.The experimental results are consistent with the theoretical analyses.