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通过线性扫描伏安法研究了焦磷酸盐溶液体系中铜电极上电沉积锡镍合金的电化学行为,分析了各种镀液成分对电沉积锡镍合金的阴极过程与沉积层组成及表面形貌的影响。结果表明,焦磷酸钾作为主配位剂起配位金属离子,增大阴极极化的作用;辅助配位剂柠檬酸钠的加入可扩大光亮区的电流密度范围,促进锡镍共沉积;添加剂氯化铵使金属离子析出电位正移,对镍具有明显的去极化作用,有利于金属共沉积;糖精钠(光亮剂)对金属离子的析出具有均匀阻化作用。焦磷酸钾、柠檬酸钠和氯化铵添加量的改变会对锡、镍的相对析出速率产生一定的影响,也影响镀层的晶粒尺寸,而糖精钠对锡、镍离子的放电相对速率没有产生大的影响,因此在其使用范围内镀层的组成都较为稳定。 相似文献
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由于大量应用各种合成添加剂,实现了酸性光亮镀锡,有关电镀过程及光亮剂的作用机理已有不少研究报导.微分电容测量和其它方法研究表明,光亮剂强烈吸附在电极表面上,阻滞了锡的电沉积过程,使过电位大大增加,以致形成细微、光亮的镀层.光亮剂的作用或许是它们在电极表面上形成吸附膜,使锡离子穿越该膜的速度缓慢,导致电荷传递速度减慢;或者是阻滞沉积过程中某一化学转化步骤,如反应2Sn~+→Sn~(2+)+Sn等,也可导致整个过程的速度减慢、不同的添加 相似文献
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电镀锡合金两则 2 0 0 32 0 1 电镀光亮锡 -铜合金电解液提出了一种电镀光亮 Sn- Cu合金电解液。该电解液能在宽广的电流密度范围内形成光亮的锡 -铜合金镀层。镀液中含有一种有机磺酸、二价锡和二价铜的有机磺酸盐 ,一种分散剂和一种光亮剂。(欧洲专利 ) EP1 1 1 1 0 97A1 ( 2 0 0 1 - 0 6- 2 7) 2 0 0 32 0 2 电沉积金 -锡合金发明了一种相当稳定的弱酸性无氰电沉积 Au-Sn合金电解液。该电解液含有金和锡的氯化物作主盐 ;柠檬酸铵为缓冲剂 ;左旋抗坏血酸做稳定剂 ;此外还含有亚硫酸钠。实验结果表明 ,采用该电解液可以获得一系列组成… 相似文献
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通过添加光亮剂, 分别在AlCl3-氯化1-甲基3-乙基咪唑(AlCl3-EMIC)和MnCl2-AlCl3-EMIC离子液体中电沉积Al和Al-Mn镀层, 重点研究了光亮剂对镀层形貌、结构以及光亮性的影响, 探讨了镀层光亮的机理。采用扫描电镜(SEM)和X射线衍射(XRD)对镀层形貌和结构进行观察和分析, 以镀层对图案的反射能力大小对光亮度进行表征。结果表明, 添加光亮剂之后, 可以电沉积出具有镜面光亮的Al和Al-Mn镀层, 并且镀层的光亮度随光亮剂浓度的增加而增加。光亮Al镀层为具有择优取向生长的纳米晶体, 而光亮Al-Mn则是纳米尺寸的非晶颗粒。镀层光亮的产生是由于光亮剂细化了Al晶粒和Al-Mn非晶颗粒, 同时使Al晶体择优取向生长造成的。 相似文献
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光亮酸性镀铜添加剂的作用 总被引:2,自引:1,他引:1
本工作研究光亮酸性镀铜添加剂——2-巯基苯骈咪唑(M)、乙撑硫脲(N)、聚二硫二丙磺酸钠(Sp)和聚乙二醇(P)对铜电沉积过程的作用。实验结果表明:M、P对铜的沉积过程的阻化作用大,可能导致产生细晶粒的镀层;N具有整平效应,而Sp的存在淡N的整平效果更好;若上述四种添加剂在镀液中的含量适宜,则在一定的电流密度范围内铜沉积层呈现光亮,光亮区随N的含量而变,当N达到某一数值时获得光亮镀层的电流密度范围最大,整平能力也最佳。 相似文献
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It is much importance to develop novel multifunctional delivery systems for the combination therapy of drug and gene. In this work, a novel conjugate, polyethylene glycol‐polyethylenimine‐tetrachloroplatinum (IV) (PEG‐PEI‐Pt), with good abilities of antitumor and gene delivery was proposed by combining PEG (Mw 3400 Da), low molecular weight PEI (Mw 800 Da), and tetrachloroplatinum (IV). The antitumoral and gene transfection activities of PEG‐PEI‐Pt were analyzed in many tumor (A549, A375, HepG‐2, HuH‐7, and B16 cells) and normal (COS‐7 cells) cell lines. Similar to cisplatin (one platinum anticancer drug), PEG‐PEI‐Pt showed much higher sensitivity in tumor cells than in normal cells. More importantly, PEG‐PEI‐Pt had a potential to treat drug‐resistant tumors. Almost no transfection efficiency was observed for PEI (Mw 800 Da) and PEG‐PEI. Very interestingly, PEG‐PEI‐Pt could condense plasmid DNA efficiently, and exhibited good transfection efficiency in B16, HepG‐2, A375 and COS‐7 cells, comparable to even higher than PEI 25 kDa. In addition, PEG‐PEI‐Pt could also effectively deliver siRNA into the cytoplasm of tumor cells. With the good antitumoral and gene delivery abilities, PEG‐PEI‐Pt may have a great potential for combination therapy of drug and gene. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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Amphiphilic linear–hyperbranched polymer poly(ethylene glycol)–branched polyethylenimine–poly(ϵ‐caprolactone): synthesis,self‐assembly and application as stabilizer of platinum nanoparticles 下载免费PDF全文
Amphiphilic linear–hyperbranched polymer poly(ethylene glycol)–branched polyethylenimine–poly(?‐caprolactone) (PEG‐PEI‐PCL) was synthesized by progressively conjugating PEG (one chain) and PCL (multi‐chains) to PEI (hyperbranched architecture) with a yield of 87%. PEG‐PEI‐PCL forms nano‐sized uniform spherical micelles by self‐assembly in water. The micelles had an average diameter of 56 nm determined using dynamic light scattering and 35 nm observed from transmission electron microscopy images. PEG‐PEI‐PCL was used as a stabilizer of platinum nanoparticles (PtNPs) for the first time. The particle diameter of PEG‐PEI‐PCL‐stabilized PtNPs was 7.8 ± 1.4 nm. Amphiphilic (hydrophilic–hydrophilic–hydrophobic) and hyperbranched (linear–hyperbranched–grafted) structures enabled PtNPs to effectively stabilize and disperse in liquid‐phase synthesis. The highly disperse PtNPs in PEG‐PEI‐PCL micelles improved the catalytic activity for the reduction of 4‐nitrophenol with a catalytic yield of near 100%. © 2016 Society of Chemical Industry 相似文献
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Jian CHEN Jiding LI Xia ZHAN Xiaolong HAN Cuixian CHEN 《Frontiers of Chemical Science and Engineering》2010,4(3):300
This study investigated the effect of poly(ethylene glycol) (PEG) additive as a pore-former on the structure formation of membranes and their permeation properties connected with the changes in thermodynamic and kinetic properties in the phase inversion process. The membranes were prepared by using polyetherimide/N-methyl-2-pyrrolidone/PEG (PEI/NMP/PEG) casting solution and water coagulant. The resulting membranes, prepared by changing the ratio of PEG to PEI, were characterized by scanning electron microscope (SEM) observations, measurements of water flux and γ-globin rejection. The thermodynamic and kinetic properties of the membrane-forming system were studied through viscosity. The pore radius distribution curves were especially obtained by differential scanning calorimetry (DSC). Furthermore, the membranes were characterized for pure water flux and rejection of solute and by SEM observation. The filtration results agreed well with the SEM observations. As expected, PEG with a fixed molecular weight (PEG 600) acted as a pore forming agent, and membrane porosity increased as the PEG content of the casting solution increased. 相似文献
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Jian Chen Jiding Li Xia Zhan Xiaolong Han Cuixian Chen 《Frontiers of Chemical Engineering in China》2010,4(3):300-306
This study investigated the effect of poly (ethylene glycol) (PEG) additive as a pore-former on the structure formation of
membranes and their permeation properties connected with the changes in thermodynamic and kinetic properties in the phase
inversion process. The membranes were prepared by using polyetherimide/N-methyl-2-pyrrolidone/PEG (PEI/NMP/PEG) casting solution and water coagulant. The resulting membranes, prepared by changing
the ratio of PEG to PEI, were characterized by scanning electron microscope (SEM) observations, measurements of water flux
and γ-globin rejection. The thermodynamic and kinetic properties of the membrane-forming system were studied through viscosity.
The pore radius distribution curves were especially obtained by differential scanning calorimetry (DSC). Furthermore, the
membranes were characterized for pure water flux and rejection of solute and by SEM observation. The filtration results agreed
well with the SEM observations. As expected, PEG with a fixed molecular weight (PEG 600) acted as a pore forming agent, and
membrane porosity increased as the PEG content of the casting solution increased. 相似文献
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Polypiperazine-amide membranes were modified with poly(ethyleneimine) (PEI) by self-assembled method, through which PEI molecules were fixed on the membrane surface by ionic interaction. In the experiments, the PEI concentration ranged from 50 to 2000 mg·L?1 while the depositing time was fixed at 20 min. The results showed that low PEI concentration resulted in a slight increase of pure water flux, which was attributed to the enhanced membrane surface hydrophilicity. The PEI adsorption on membrane surface had less effect on the re-jections to neutral PEG and sucrose, but improved the rejections to divalent cationic ions and methylene blue as the result of reversion of the membrane surface charge from negative to positive according to the XPS analysis and zeta potential measurements. The membrane modified at PEI=1500 mg·L?1 exhibited high rejection to methylene blue (MB) and is potential to be applied in the treatment of effluents containing positively charged dyes. 相似文献
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用浊度法研究了聚合物对烷基苯磺酸钠与钙离子的相互作用的影响,不同聚合物,如聚乙烯亚胺(PEI)、聚乙烯吡咯烷酮(PVP)和聚乙二醇(PEG)在同一pH条件下的研究结果表明,PEI比后两能更好地抑制LAS钙盐的形成。同时一聚合物在不同pH条件下的研究发现,PEI只有在一个适当的pH范围内,即自身具有适当的电荷密度,才能很好地发挥其上述作用。在体系中存在一定量的AEO3条件下,也观察到了PEI在抑制 相似文献
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In this article, we report the surface modification of branched polyethyleneimine (PEI) for improved biocompatibility. PEIs with different surface functionalities were synthesized via covalent modification of the PEI amines, including neutralized PEI modified with acetic anhydride, negatively charged PEI modified with succinic anhydride, hydroxylated PEI modified with glycidol, and PEI–poly(ethylene glycol) (PEG) conjugates modified with both PEG and acetic anhydride. The modified PEI derivatives were characterized with 1H‐NMR, Fourier transform infrared spectroscopy, and ζ‐potential measurements. An in vitro cytotoxicity assay of mouse fibroblasts revealed that the biocompatibility of PEI was significantly improved after these modifications. The neutral and negatively charged PEIs were nontoxic at concentrations up to 200 μg/mL, whereas the pristine PEI was toxic to cells at concentrations as low as 10 μg/mL. The successfully modified PEIs with different surface charges and functionalities may provide a range of opportunities for various biomedical applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
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Through a dip‐coating technique, carbon membranes were produced from a polymer blend consisting of the thermally stable polymer polyetherimide (PEI) and the thermally labile polymer polyethylene glycol (PEG). The PEG/PEI carbon membranes were synthesized on an alumina support coated with an Al2O3 intermediate layer. The polymer blend ratio and carbonization temperature influenced the structure and permeation performance of the derived carbon membranes. The porosity of the PEG/PEI carbon membranes increased with higher PEG content in the blends. However, the derived carbon membranes tended to lose gas permeability with raising the carbonization temperatures. The carbon membranes were successfully optimized in order to achieve the highest CO2/CH4 and CO2/N2 selectivities. 相似文献
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Rongqiang Liao Shouhui Yi Manshuo Liu Wenling Jin Prof. Bo Yang 《Chembiochem : a European journal of chemical biology》2015,16(11):1622-1628
A targeting gene carrier for cancer‐specific delivery was successfully developed through a “multilayer bricks‐mortar” strategy. The gene carrier was composed of adamantane‐functionalized folic acid (FA‐AD), an adamantane‐functionalized poly(ethylene glycol) derivative (PEG‐AD), and β‐cyclodextrin‐grafted low‐molecular‐weight branched polyethylenimine (PEI‐CD). Carriers produced by two different self‐assembly schemes, involving either precomplexation of the PEI‐CD with the FA‐AD and PEG‐AD before pDNA condensation (Method A) or pDNA condensation with the PEI‐CD prior to addition of the FA‐AD and PEG‐AD to engage host–guest complexation (Method B) were investigated for their ability to compact pDNA into nanoparticles. Cell viability studies show that the material produced by the Method A assembly scheme has lower cytotoxicity than branched PEI 25 kDa (PEI‐25KD) and that the transfection efficiency is maintained. These findings suggest that the gene carrier, based on multivalent host–guest interactions, could be an effective, targeted, and low‐toxicity carrier for delivering nucleic acid to target cells. 相似文献