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41.
本方法适合于铅精矿银含量在1000~2000g/t。此方法采用灰吹留铅1~2g左右,用硫氰酸钾滴定银量w1与灰渣配料二次试金,灰吹留铅0.5g左右,硝酸溶解定容,原子吸收测定渣中银量w2,两者之和即为最终测定值。实验中用与试样等量银粉和纯铅混合滴定,验证回收率及留铅干扰程度。 相似文献
42.
为了研究石灰岩和玄武岩集料的微纳观特征,利用原子力显微镜(AFM)测试了其表面纹理与黏附力,并导入SPSS软件校验了数据的稳定性和区分度,对比分析了石灰岩与玄武岩集料在微纳观特征上的异同.结果表明:AFM可有效测试集料的表面纹理,数据稳定性强,区分度高,但测试集料的黏附力时,数据的随机性大,存在着一定的误差;石灰岩表面纹理粗糙、黏附力峰值较高、分布比较随机,与沥青之间的黏结呈"散点式"分布,而玄武岩表面纹理光滑、具有流纹结构,黏附力峰值较低、分布比较均匀,与沥青之间的黏结呈"整体式"分布. 相似文献
43.
采用原子力显微镜(AFM)、动态剪切流变(DSR)试验,对比研究了SBS改性沥青与70~#沥青老化前后微观表面力学性能与宏观力学性能的变化.研究发现,室温下SBS改性沥青与70~#沥青微观表面均出现了类似蜂型的微观结构,且老化后蜂型结构聚集,70~#沥青表现更为突出;SBS改性沥青较70~#沥青微观力学性能更加稳定,从微观层面上证明了SBS改性沥青具有更好的抗老化性能,同时采用DSR试验对二者进行了对比研究,在宏观力学行为上也得出相同结论.对沥青微观表面杨氏模量与储存弹性模量进行线性回归拟合,结果显示二者显著相关,表明沥青微观表面杨氏模量对沥青储存弹性模量具有直接影响. 相似文献
44.
A. Sakaguchi K. Kawai T. Imanaka S. Endo M. Yamamoto 《The Science of the total environment》2010,408(22):5392-5398
The first results on the feasibility of using 236U to reconstruct the level and spatial distribution of close-in fallout deposition from the Hiroshima A-bomb are reported, coupled with the use of global fallout 137Cs and 239 + 240Pu. The results for global fallout 236U in soil samples (0-30 cm) from Ishikawa prefecture showed that the deposition density of 236U from the global fallout can be accurately evaluated using AMS. All deposited 236U, 137Cs and 239 + 240Pu appeared to have been recovered using 30-cm cores. It was also noted from the depth profiles for 236U/239 + 240Pu and 236U/137Cs ratios that the downward behavior of 236U in the soil was apparently similar to that of 239 + 240Pu, while the 137Cs was liable to be retained in upper layers compared with 236U and 239 + 240Pu. The accumulated levels were 1.78 × 1013 atoms m− 2 for 236U, 4340 Bq m− 2 for 137Cs and 141 Bq m− 2 for 239 + 240Pu. The ratios of 236U/137Cs and 236U/239 + 240Pu were (4.10 ± 0.12) × 109 and (1.26 ± 0.04) × 1011 atoms Bq− 1, respectively. Results of 236U, 137Cs and 239 + 240Pu measurements for the seven soil cores (0-30 cm) from Hiroshima were discussed on the basis of ratios of 236U/137Cs and 236U/239 + 240Pu by comparing with those from the background area in Ishikawa, indicating that the global fallout dominates the current level of 236U accumulation in soil in the Black-rain area around Hiroshima after the Hiroshima bomb, and the contribution of the close-in fallout 236U produced by the Hiroshima A-bomb seems difficult to observe. 相似文献
45.
Tzu-Kang Chin Ming-Wei Liao Tsong-Pyng Perng 《Journal of the American Ceramic Society》2022,105(10):6041-6048
A polysulfone (PSF) hollow fiber composed of interconnected nanofibers within its wall was employed as a template to deposit with a layer of TiO2 by atomic layer deposition. Direct nitridation of the TiO2-coated PSF hollow fiber at 800 and 1000°C was conducted, and a new hierarchical structure of TiOxN1−x and TiN@nitrogen-doped carbon hollow fibers, respectively, was formed. The PSF fiber served as the source of carbon and was directly transformed to a nitrogen-doped carbon fiber because the shape change was confined by the TiO2 coating. In the meantime, TiOxN1−x or TiN was formed after the nitridation of TiO2. X-ray photoelectron spectrometric analysis indicated that there was no chemical bonding between the nitridized coating and the carbon nanofibers. It implies that the nitridation of TiO2 and carbonization of PSF proceed independently and simultaneously in the nitridation process. Raman spectroscopic analysis also confirmed the formation of graphitic lattice and Ti–N bonding. Electrical measurement indicated that both fibers were highly conductive, with the electrical resistivity in the order of 10−5 Ω m, which is lower than those of amorphous carbon and graphite along the direction perpendicular to the basal plane. 相似文献
46.
Dendrimers are novel three dimensional, hyperbranched globular nanopolymeric architectures. Attractive features like nanoscopic size, narrow polydispersity index, excellent control over molecular structure, availability of multiple functional groups at the periphery and cavities in the interior distinguish them amongst the available polymers. Applications of dendrimers in a large variety of fields have been explored. Drug delivery scientists are especially enthusiastic about possible utility of dendrimers as drug delivery tool. Terminal functionalities provide a platform for conjugation of the drug and targeting moieties. In addition, these peripheral functional groups can be employed to tailor-make the properties of dendrimers, enhancing their versatility. The present review highlights the contribution of dendrimers in the field of nanotechnology with intent to aid the researchers in exploring dendrimers in the field of drug delivery. 相似文献
47.
Polymer brush coatings for combating marine biofouling 总被引:4,自引:0,他引:4
Wen Jing Yang Koon-Gee Neoh En-Tang Kang Serena Lay-Ming Teo Daniel Rittschof 《Progress in Polymer Science》2014
A variety of functional polymer brushes and coatings have been developed for combating marine biofouling and biocorrosion with much less environmental impact than traditional biocides. This review summarizes recent developments in marine antifouling polymer brushes and coatings that are tethered to material surfaces and do not actively release biocides. Polymer brush coatings have been designed to inhibit molecular fouling, microfouling and macrofouling through incorporation or inclusion of multiple functionalities. Hydrophilic polymers, such as poly(ethylene glycol), hydrogels, zwitterionic polymers and polysaccharides, resist attachment of marine organisms effectively due to extensive hydration. Fouling release polymer coatings, based on fluoropolymers and poly(dimethylsiloxane) elastomers, minimize adhesion between marine organisms and material surfaces, leading to easy removal of biofoulants. Polycationic coatings are effective in reducing marine biofouling partly because of their good bactericidal properties. Recent advances in controlled radical polymerization and click chemistry have also allowed better molecular design and engineering of multifunctional brush coatings for improved antifouling efficacies. 相似文献
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