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Alexandra FriedmanNina Perkas Yuri KoltypinAharon Gedanken 《Applied Surface Science》2012,258(7):2368-2372
The inner and the outer walls of hollow tubing with an inner diameter of 0.4-0.9 cm and an outer diameter of 0.6-1.3 cm were coated with silver nanoparticles (NPs) by a one-step process using ultrasound irradiation. The structure and morphology of the nanoparticles (NPs) inside the hollow tubing and on the outer surface were characterized using methods such as XRD, TEM, HR-TEM, and HRSEM. The inner surface of the tubing was found to be coated with more silver than the outer surface. The coating was done on tubing made of rubber, PVC, Teflon and polyethylene. Sonochemistry is demonstrated as a method for depositing nanoparticles on the inner wall of a tube. 相似文献
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Countercurrent chromatography (CCC) is a separation technique in which two immiscible liquid phases are used for the preparative purification of synthetic and natural products. In CCC the number of repetitive mixing and de-mixing processes, the retention of the stationary phase and the mass transfer between the liquid phases are significant parameters that influence the resolution and separation efficiency. Limited mass transfer is the main reason for peak broadening and a low number of theoretical plates along with impaired peak resolution in CCC. Hence, technical improvements with regard to column design and tubing modifications is an important aspect to enhance mixing and mass transfer. 相似文献
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In the present study, three different commercial bio-based polyamides (bio-PAs), namely polyamide 610 (PA610), polyamide 1010 (PA1010), and polyamide 1012 (PA1012), were processed by profile extrusion with an annular die. These aliphatic homopolyamides, also known as “green nylons”, are industrially produced by polycondensation reaction of diamines and dicarboxylic acids that are partially or fully obtained from naturally occurring castor oil. The profile-extruded bio-PA tubes were characterized and compared in terms of their thermal, thermomechanical, and mechanical properties and also water uptake. Resultant comparative evaluation indicated that both the methylene-to-amide (CH2/CONH) ratio and the crystallinity degree of the bio-PAs played the main role in determining the performance of the tubes. Due to significant differences in their CH2/CONH ratio, the PA610 tubes showed the highest thermal properties while the tubes made of PA1012 presented the highest flexibility and lowest water uptake. Interestingly, the fully bio-based PA1010 tubes offered the most balanced and enhanced engineering performance, which was ascribed to the high crystallinity achieved during profile extrusion. The here-developed bio-PA tubes can fulfil demanding technical requirements and these also certainly represent a sustainable answer to the rising demand for new high-performance biopolymers for engineering applications. 相似文献
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