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Basic Materials Engineering
Published in David A. Hansen, Robert B. Puyear, Materials Selection for Hydrocarbon and Chemical Plants, 2017
David A. Hansen, Robert B. Puyear
Polyvinyl Chloride (PVC). PVC is popular in the form of plastic pipe because of its easy-working properties. The material may be joined by either solvent bonding or hot-air welding. Because of its relatively poor solvent resistance and thermal stability, its service is usually restricted to handling water solutions, inorganic chemicals and specific organic compounds such as alcohols and straight-chain hydrocarbons. PVC has excellent resistance to inorganic acids and alkalis, and is one of the most resistant plastics for strong inorganic oxidizing agents such as chlorine water and dilute nitric acid. Its upper temperature limit is about 150°F(66°C).
Reconfigurable metamaterials for optoelectronic applications
Published in International Journal of Optomechatronics, 2020
In 2017, a design of plasmonic nanocavities integrated with a photonic-plasmonic hybrid circuit is applied for the near-field transportation signal in the nanocavity.[116] In 2018, a thin film phase modulator employing organic nonlinear optical molecules is proposed to act as coherent electric field detector for THz communication system.[117] A THz metamaterial based high electron mobility transistor (HEMT) is demonstrated to be capable of modulation depths up to 33% at 0.46 THz with all electrical control, and the modulation of THz radiation is up to 10 MHz.[66] It opens the avenue for metamaterial implanted into transistor fields. In 2020, a reconfigurable THz filter composed of ring-shaped and cross-shaped nanostructures is presented by Lin’s research group.[118] It was used to control the output frequency window for an indoor THz wireless communication system, which makes the data rates up to 100 Gb/s more possible. These results pave a way for the metamaterials to be used in the future optical communication with a cost-effective, flexible, and applicable approach.
Self-assembled molecular devices: a minireview
Published in Instrumentation Science & Technology, 2020
However, the transistor memory designed by the Tseng group[66] needs to add a charge storage layer between the gate dielectric and the organic semiconductor channel. In order to avoid this complex phenomenon, Wang et al.[38] designed a new diblock copolymer poly(3-hexylthiophene)-block-poly(pendentisoind igo) (P3HT44-B-PISOn) with donor (poly (3-hexylthiophene) (P3HT)) - acceptor (poly (pendentisoindigo) (PISO)). These devices do not need additional charge storage layers, and have the charge transport and storage characteristics of high-performance transistor memory, with the P3HT and PISO blocks acting as charge transport and storage element, respectively.
Liquid crystal elastomers: an introduction and review of emerging technologies
Published in Liquid Crystals Reviews, 2018
Sabina W. Ula, Nicholas A. Traugutt, Ross H. Volpe, Ravi R. Patel, Kai Yu, Christopher M. Yakacki
The effect of synthetic history was first examined in side-chain LCEs by Davis et al. in 1996 and later by Urayama et al. in 2009 [97,99]. It was then investigated in main-chain LCEs by Traugutt et al.[100] who showed that actuation, work capacity, dissipation, and elastic modulus are all dependent on the state of alignment during synthesis. The results demonstrated that actuation is significantly impacted, with i-PNEs achieving 66% to 126% strain and n-PNEs achieving 3% to 61% strain for paired networks with tailored crosslinking densities. This discrepancy is due to the order parameter of n-PNEs being lower than that of i-PNEs, with 0.37 < S < 0.50 for the former and S = 0.54 for the latter. Crosslinking density also affected the actuation abilities of the elastomers: i-PNEs actuated twice as much as their n-PNE counterparts at low crosslinking densities [100]. This might suggest that i-PNEs are more suitable for applications requiring large strain amplitudes. Conversely, n-PNEs demonstrated higher elastic modulus values and elastically recovered higher magnitudes of strain when stretched and released. However, it is more difficult to measure Tni via differential scanning calorimetry for n-PNEs, as the enthalpy well is not as distinct as in i-PNE networks [94,100,101]. Although the effect of synthetic history on side-chain LCEs has also been investigated, direct comparisons between side-chain and main-chain behavior cannot be made due to the inherent differences that arise from their chain conformations [99,102–106]. For both polymer architectures, the phase of the mesogens during synthesis plays an important role in the development of the elastomer’s macroscopic behavior. Therefore, it is encouraged that researchers identify the conditions under which polymerization occurs, as two identical chemistries could have different physical properties depending on their synthetic history.