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41.
Tangjian Cheng Genpin Lv Yitao Li Hao Yun Lingfei Zhang Yongmao Deng Liping Lin Xiangjun Luo Junmin Nan 《大分子材料与工程》2021,306(7):2100086
The low dielectric polymer films have drawn great attention to the application as the dielectric insulating materials in high-frequency circuit boards, while the weak adhesion to the copper foils and the poor processability resulted from the fluorinated or rigid structures limited their high-frequency application. In this work, the low dielectric and high adhesive polyimide/fluorinated ethylene propylene (PI/FEP) nanocomposite film for high-frequency flexible circuit board application is developed. It is indicated that the fluorocarbon surfactants can significantly improve the dispersion of FEP in PI substrate, and thus, the PI/FEP nanocomposite film exhibits excellent mechanical properties, including the tensile strength increases to 46.6 MPa and the elongation at the break increases to 13.7%. Importantly, at the high-frequency of 10 GHz, the 60 wt% FEP filled PI nanocomposite film displays an ultralow dielectric loss (0.006) and a reduced dielectric constant (2.69). In addition, the high-frequency flexible circuit board with the PI/FEP film as the dielectric insulating layer has a high peel strength of 0.75 N mm−1, indicating this PI/FEP nanocomposite film can meet the requirements of the high-frequency flexible circuit board application. 相似文献
42.
Sheng-lian LUO Lin YUAN Li-yuan CHAI Xiao-bo MIN Yun-yan WANG Yan FANG Pu WANG 《中国有色金属学会会刊》2006,16(6):1431-1435
Biosorption of heavy metal ions, such as Cu2+, Cd2+ and Zn2+, was carried out using waste activated sludge from municipal sewage treatment plant as adsorption material, and the effects of parameters, such as pH value, temperature, reaction time and sorption duration, were studied in detail. The results indicate that the removal rates of Cu2+, Zn2+ and Cd2+ with low concentration are 96.47%, 80% and 90%, respectively, adsorbed by waste activated sludge. Little effect of dosage of activated sludge on the adsorption of Cu2+ and more effects on the adsorption of Zn2+ and Cd2+ are observed. Little effect of temperature is observed, while pH value and adsorption time exert important influence on the sorption process. The adsorption behaviors of heavy metal ions all have parabolic relationships with pH value. The optimum pH value is between 6 and 10, and the optimum adsorption time is 1 h. In single heavy metal ion system, the sorption processes of Cu2+, Zn2+ and Cd2+ are in accordance with Freundlich model, which indicates that it is suitable for the treatment of these three heavy metal ions using intermittent operation. In addition, the sorption capacity of the sludge for Cu2+ is preferential to the other two ions. 相似文献
43.
低熔点Cu-P基中间合金及其变质效果 总被引:3,自引:1,他引:3
利用差示扫描量热仪(DSC)、扫描电子显微镜(SEM)和金相显微镜等手段对Cu-P基中间合金进行了研究。结果表明,在二元共晶Cu-P中间合金中加入一定量的Sn可制成低熔点的Cu-16Sn-8P中间合金;在此基础上研制出一种熔点为630℃左右的低熔点的多元Cu-P基中间合金。与Cu-P中间合金相比,该低熔点多元Cu-P基中间合金对过共晶AI-24Si合金具有更好的变质效果。同时,该中间合金对ZL109合金也具有良好的变质效果。 相似文献
44.
半固态镁合金流变成形技术及装备 总被引:7,自引:4,他引:7
研究了镁合金半固态流变成形技术及装备,结果表明,多功能螺纹元件组合的双螺杆制浆装置制备的浆料晶粒细小(10~50μm),固相率可在5%~50%范围内调整,封闭式加热保温,快开快关控制的浆料存储与输送装置,较好地解决了浆料连续制备与间歇压铸的配套;生产的半固态压铸件,强度提高了20%以上。 相似文献
45.
消失模涂料对EPS裂解产物传输特性的影响 总被引:1,自引:0,他引:1
针对消失模铸造过程中EPS模样裂解产物,涂料性能对铸件质量的影响,介绍了一种消失模涂料对EPS裂解产物传输特性的测试仪器吸测试方法。讨论了消失模涂料厚度、涂层高温透气率、涂料组分对EPS裂解产物传输特性的影响。 相似文献
46.
In this paper, the author dipped surface vapor oxidized H13 steel specimens into 700℃ molten aluminum liquid for a certain period of time. Analyze the intermetallic phases formed on the H13 samples surface with optical microscope and X-ray diffraction method. The observation of immersion test sample's cross-section shows that Fe3O4 film will protect die substrate from molten aluminum erosion. The identification of the intermetallic phases reveals that they consist of 2parts, which is named as the composite layer and the compact layer. Further investigations are made in order to know the phase constituents of the 2 layers, they are Al8Fe2Si (outer composite layer), (AlCuMg) and Al5Fe2 (compact layer),respectively. The experimental results show that on the same specimen, a convex surface with bigger radius of curvature is more likely to be molten and the melting loss speed is also faster than a flat and smooth surface. The thickness of compact layer on a smooth surface is much bigger than that of the convex surface. Therefore, the author supposes the compact layer is favorable in stabilizing the die surface material from further melting loss, as their formation on the die surface, the melting loss speed will decrease. 相似文献
47.
48.
间甲基苯甲脒盐酸盐是农药和医药研究领域一个十分重要的原材料和中间体。间甲基苯甲脒盐酸盐的两步合成法是先以盐酸羟胺制备间甲基苯甲脒肟再通过加氢还原即可得到。在制备间甲基苯脒肟时,单因素考察了常规热反应、微波合成法、超声波合成法对间甲基苯脒肟产率的影响。并探索了一锅法合成间甲基苯甲脒盐酸盐的可行性。所得化合物由沸点、氢谱、质谱确认。实验结果表明:三种方式合成间甲基苯甲脒肟,其产率从大到小依次为:微波合成法>超声波合成法>常规热反应。本实验采用两步法合成间甲基苯甲脒盐酸盐的总产率为58.05%,采用一锅法合成间甲基苯甲脒盐酸盐的产率为78.19%。两步法和一锅法均可用于合成间甲基苯甲脒盐酸盐。 相似文献
49.
50.
蚕蛹蛋白纤维的阳离子改性及其漂白性能研究 总被引:1,自引:0,他引:1
研究了蚕蛹蛋白纤维经阳离子改性处理后,纤维中阳离子基团和改性剂用量的关系,对阳离子改性后蚕蛹蛋白纤维的H2O2漂白特性进行了探讨。结果表明:蚕蛹蛋白纤维经阳离子改性后漂白效果明显提高。改性纤维上的季铵正离子能加快溶液中HO2离子的吸附,在纤维内部进行“定点”漂白,从而提高纤维的漂白效果。 相似文献