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- Yang, Huiqing, et al.
(författare)
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Protic Quaternary Ammonium Ionic Liquids for Catalytic Conversion of CO2 into Cyclic Carbonates : A Combined Ab Initio and MD Study
- 2018
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Ingår i: Industrial & Engineering Chemistry Research. - : AMER CHEMICAL SOC. - 0888-5885 .- 1520-5045. ; 57:21, s. 7121-7129
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Tidskriftsartikel (refereegranskat)abstract
- The mechanism of CO2 fixation catalyzed by protic hydroxyl-functionalized quaternary ammonium ionic liquids (ILs) is investigated by two different models, the Single-IL model and the Double-IL model. The relative sequence of catalytic activity calculated by the Single-IL model is contradictory with the experimental result. The situation is totally varied when the Double-IL model is utilized. In this system, ILs are not limited to the catalyst but solvent. The ILs are incorporated into the catalytic system to consider the solvent effect rather than by the existing solvent model. When the solvent effect is included, it is better to distinguish the catalytic activity of three ILs. According to the noncovalent interaction and the atoms in molecules analysis, the highest catalytic activity of tris(2-hydroxyethyl)ammonium bromide ([HTEA]Br) is attributed to its strongest nucleophilic attack and moderate hydrogen bond interaction between IL and reactant. It is necessary to consider the interaction between ILs to get a reliable result. Moreover, the solvent effect aroused by ILs should be carefully considered.
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| 2. |
- Feng, Zhenhua, et al.
(författare)
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Multicore-Fiber-Enabled WSDM Optical Access Network With Centralized Carrier Delivery and RSOA-Based Adaptive Modulation
- 2015
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Ingår i: IEEE PHOTONICS JOURNAL. - : Institute of Electrical and Electronics Engineers (IEEE). - 1943-0655. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- We proposed and experimentally demonstrated a wavelength-space division multiplexing (WSDM) optical access network architecture with centralized optical carrier delivery utilizing multicore fibers (MCFs) and adaptive modulation based on reflective semiconductor amplifier (RSOA). In our experiment, five of the outer cores are used for undirectional downstream (DS) transmission only, whereas the remaining outer core is utilized as a dedicated channel to transmit upstream (US) signals. Optical carriers for US are delivered from the optical line terminal (OLT) to the optical network unit (ONU) via the inner core and then transmitted back to the OLT after amplification and modulation by the RSOA in the colorless ONU side. The mobile backhaul (MB) service is also supported by the inner core. Wavelengths used in US transmission should be different from that of the MB in order to avoid the Rayleigh backscattering effect in bidirectional transmission. With quadrature phase-shift keying-orthogonal frequency-division multiplexing (QPSK-OFDM) modulation format, the aggregation DS capacity reaches 250 Gb/s using five outer cores and ten wavelengths, and it can be further scaled to 1 Tb/s using 20 wavelengths modulated with 16 QAM-OFDM. For US transmission, 2.5 Gb/s QPSK-OFDM transmission can be achieved just using a low-bandwidth RSOA, and adaptive modulation is applied to the RSOA to further enhance the US data rate to 3.12 Gb/s. As an emulation of high-speed MB transmission, 48 Gb/s inphase and quadrature (IQ) modulated popularization division multiplexing (PDM)-QPSK signal is transmitted in the inner core of MCF and coherently detected in the OLT side. Both DS and US optical signals exhibit acceptable performance with sufficient power budget.
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