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The effects of different donors, acceptors, and electron bridges on various properties of novel organic electro-optic materials are investigated. We synthesized and systematically researched 12 chromophores with different donors including alkylaniline, bis(4-piperidinyl)phenyl, bis(N,N-diethyl)aniline, and julolidine derivatives and acceptors including tricyanofuran (TCF) or phenyl-trifluoromethyl-tricyanofuran (3F-TCF) and pentafluorobenzene-tricyanofuran (5F-TCF) linked together via isophorone derivatives as the bridges. We tested the thermodynamic characteristics, photophysical properties, DFT theoretical calculations, and electro-optical properties of 12 chromophores to summarize the relationship between the chromophore structure and performance. The results indicate that not the strongest donor pairs with the strongest acceptors exhibit the best performance, for example, chromophores C5 and D5 with strong bis(N,N-diethyl)aniline and julolidine donors exhibit the highest electro-optic coefficients (245 and 228 pm V−1), while they only modify with relatively weaker 5F-TCF acceptors. For weak alkylaniline, bis(4-piperidinyl)phenyl donors, the 3F-TCF acceptor can achieve the maximum electro-optic coefficient (151 and 189 pm V−1). [ABSTRACT FROM AUTHOR]

Featured Application: The work in this paper provides some basic theoretical and practical reference value for the energy and exergy analysis, calculation, process optimization, and energy conservation research of the hydrogen-based direct reduction shaft furnace process, which is helpful for promoting its further industrial application. The traditional production mode using coal as the main energy source is not conducive to the sustainable development of the iron and steel industry (ISI). The hydrogen-based direct reduction shaft furnace (HDRSF) process is a feasible technical route for promoting the green development of the ISI. However, there is a lack of comprehensive analysis with respect to the energy utilization and process flow of the HDRSF method. To address these issues, a systemic material–energy–exergy model of HDRSF is established. An improved HDRSF process incorporating waste heat recovery is also proposed, and energy consumption intensity and exergy intensity are used as assessment metrics. This study's findings indicate that the proposed waste heat recovery can considerably lower gas demand and energy consumption intensity, but exergy intensity has little effect. The reducing gas demand drops from 2083 m3 to 1557 m3, the energy consumption intensity drops from 2.75 × 107 kJ to 1.70 × 107 kJ, and the exergy intensity drops from 1.08 × 107 kJ to 1.05 × 107 kJ when the reducing gas temperature is 900 °C, H2:CO = 1:1; meanwhile, the recovery rate of waste heat reaches 40%. This study can serve as a reference for actual HDRSF process production. [ABSTRACT FROM AUTHOR]

We report the development of an optical feedback linear cavity-enhanced absorption spectroscopy instrument for HO2 detection using a distributed feedback (DFB) diode laser operating at 1506 nm. A direct and accurate method of reflectivity measurement based on the analysis of cavity mode signals was proposed. A differential circuit was used to judge the zero crossing point of the optical feedback cavity mode in the center of the frequency locking region, and shift the laser operating current to the non-resonant region. In this way, a ring-down signal was obtained with a time of 17.9 μs, corresponding to an effective absorption pathlength of 5.37 km. Combining the standing wave condition, the relationship between cavity length and drive voltage of the PZT mounted on the cavity rear mirror is translated into a correlation between the transmitted light wavenumber and the PZT voltage. The spectral resolution was improved from 290 MHz to 97 MHz by precisely tuning the PZT voltage. The achieved detection sensitivity of the system was 7 × 10− 10 cm− 1 with a data acquisition time of 10.6 s. The absorption spectrum of HO2 at 6638.205 cm− 1 was measured at a cell pressure of 50 mbar with a detection limit of 3.24 × 109 molecule/cm3. [ABSTRACT FROM AUTHOR]

Optical freciuency comb-based Fourier transform spectroscopy has the features of broad spectral bandwidth, high sensitivity, and multiplexed trace gas detection, which has valuable application potential in the fields of precision spectroscopy and trace gas detection. Here, we report the development of a mid-infrared Fourier transform spectrometer based on an optical frequency comb combined with a Herriott-type multipass cell. Using this instrument, the broadband absorption spectra of several important molecules, including methane, acetylene, water molecules and nitrous oxide, are measured by near real-time data acquisition in the 2800–3500 cm−1 spectral region. The achieved minimum detectable absorption of the instrument is 4.4xl0−8 cm−1·Hz−1//2 per spectral element. Broadband spectra of H2O are fitted using the Voigt profile multispectral fitting technique and the consistency of the concentration inversion is 1%. Our system also enables precise spectroscopic measurements, and it allows the determination of the spectral line positions and upper state constants of N2O in the (0002)–(1000) band, with results in good agreement with those reported by Toth [Appl. Opt. 30, 5289 (1991)]. [ABSTRACT FROM AUTHOR]

The denitrification efficiency of carbon‐based zero valent iron catalyst (C‐ZFe) for low‐temperature selective catalytic reduction (SCR) (<140°C) highly depends on the structural species of iron oxide (FexOy) and the physicochemical properties of the catalyst. In the study, we investigated the main factors affecting the low‐temperature denitrification efficiency of C‐ZFe such as temperature, iron content and O2. The results showed that the average NOX conversion was 72.6 % at 135°C when the space velocity was 459 h−1 and the mass ratio of carbon to iron was 15 % to 85 %. The surface morphology and structure of C‐ZFe were characterized by the surface area and pore size distribution measurements, X‐ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and X‐ray photoelectron spectroscopy (XPS). The results indicated that the iron on the catalyst surface was oxidized by O2 to Fe2O3, which could retain NO and then formed intermediate products. NO entered the mesoporous structure along C‐ZFe surface and proceeded a catalytic reduction reaction with the adjacent carbon. [ABSTRACT FROM AUTHOR]