[en] An unseeded surfactant-free styrene emulsion polymerization is employed to prepare core-crosslinked particles with poly (ethylene oxide) monomethyl ether (mPEO) macro-revesible addition fragmentation chain transfer (RAFT) agent as both the stabilizer and the control agent. The pegylated amphiphilic macro-RAFT agent (mPEO5000-TTC) was synthesized via coupling poly(ethylene oxide) monomethyl ether with a hydrophobic dodecyl trithiocarbonate chain and utilized to form the micelles and control the polymerization and crosslinking of styrene in aqueous solution. The FTIR, 1H NMR, TEM (transmission electron microscopy), dynamic light scattering (DLS) were used to clarify the structure and morphology of nanoparticle. The thermal performance of nanoparticles was measured by TGA (thermogravimetric analysis). The results showed that with the increasing of concentration monomer, the produced size of particles enlarged and then tended to be maximum, while the thermal stability was decreased comparative to the mPEO precursor. The thermal stability of crosslinked particles reflected lower than that of uncrosslinked, which is elucidated with formation and collapse of micelles and micro-phase separation. (paper)

[en] Two-dimensional (2D) photodetecting materials have shown superior performances over traditional materials (e.g., silicon, perylenes), which demonstrate low responsivity (R) (<1 AW${}^{-<!--\; ???\; -->1}$), external quantum efficiency (EQE) (<100%), and limited detection bandwidth. Recently, 2D indium selenide (InSe) emerged as high-performance active material in field-effect transistors and photodetectors, whose fabrication required expensive and complex techniques. Here, it is shown for the first time how molecular functionalization with a common surfactant molecule (didodecyldimethylammonium bromide) (DDAB) represents a powerful strategy to boost the (opto)electronic performances of InSe yielding major performance enhancements in phototransistors, Schottky junctions, and van der Waals heterostructures via a lithography-compatible fabrication route. The functionalization can controllably dope and heal vacancies in InSe, resulting in ultrahigh field-effect mobility (10${}^3$ cm${}^2$ V${}^{-<!--\; ???\; -->1}$ s${}^{-<!--\; ???\; -->1}$) and photoresponsivity (10${}^6$ A W${}^{-<!--\; ???\; -->1}$), breaking the record of non-graphene-contacted 2D photodetectors. The strategy towards the molecular doping of 2D photodetecting materials is efficient, practical, up-scalable, and operable with ultra-low power input, ultimately paving the way to next-generation 2D opto-electronics. (© 2021 Wiley-VCH GmbH)

[en] Highlights: • Siderite is effective to activate PDS to degrade sulfadiazine. • The role of singlet oxygen under different pH value is investigated. • The staged kinetic fitting describes the role of ROS. • The unique intermediate caused by ¹O₂ is illustrated. Occurring naturally siderite (FeCO₃) was used as the heterogeneous catalyst to activate peroxodisulfate (PDS) for the degradation of sulfadiazine under different initial pH values. The findings of this system exhibited various ROS (e.g. ¹O₂, SO₄⁻ and OH) present during a wide range of pH values. Among them, ¹O₂ could significantly facilitate the initial degradation rate, and the increased pH enhanced the role of ¹O₂. The factors including initial pH values, siderite dosage, PDS concentration, initial contaminants concentration, and water matrix were discussed. The role of each ROS was investigated through quenching test and electron paramagnetic resonance (EPR). Furthermore, the comprehensive degradation process was proposed based on the LC-MS results. And the cycle test demonstrates the reusability of siderite at a pH of 3. Accordingly, this study is of great significance for understanding the degradation of such sulfonamide pollutants in the siderite/PDS system.

[en] In this paper, a novel variable camber guide vane (VCGV) actuated with a shape memory alloy (SMA) plate is proposed to achieve active real-time control. An analytical model is proposed to describe the relationship of SMA plates with different thicknesses between the deflection angle and temperature. Then, a numerical model of the VCGV is established to design the shape of the VCGV. Moreover, experiments of this actuator and VCGV are conducted to explore the variation of deflection angles over time for the VCGV. Results show that the deflection angle of the VCGV can be actively controlled from 0° to 8.2°. This work is expected to widen the applications of SMAs in variable guide vanes. (paper)

[en] To achieve high measurement accuracy without the restriction of fringe number, a high-accuracy phase shifting retrieval approach based on phase shifts search (PSS) is proposed. Firstly, by setting the search conditions related to the phase shifts and using the PSS method to obtain the phase shifts between the phase shifting interferograms, subsequently, the phase distribution of the sample can be accurately obtained by using the obtained phase shifts. To our knowledge, the proposed method has the highest accuracy among the multi-step arbitrary phase shifting algorithms, and it is not limited to the number of fringes and the distribution of phase shifts between the interferograms. In the case of sparse fringes, the phase can still be retrieved with high accuracy, which proves that the proposed method is a high accuracy method with fewer constraints and wider applications. The feasibility and superiority of this method are proved by the simulation analysis and experiment. (paper)

[en] Highlights: • Siderite effectively activate H₂O₂ to produce ·OH over a wide pH values range. • Siderite has a high potential to remove micropollutants (MPs) in subsurface with H₂O₂. • The detailed kinetic fitting describes the influence of parameters. • The role of lattice Fe(Ⅱ) in activating H₂O₂ is demonstrated. Siderite is a conventional mineral of sedimentary rock and can activate H₂O₂ to produce hydroxyl radicals (·OH). Bisphenol A (BPA), 2,4-dichlorophenoxyacetic acid (2,4-D), and sodium sulfadiazine are selected as typical micropollutants to be degraded in a siderite-activated H₂O₂ system. To determine the influence of solution chemistry on siderite-activated Fenton-like reactions, the amount of ·OH was quantified by using benzoic acid as a probe molecule, and then, kinetic fitting was used to analyze the reaction rate. The results showed that in the range of pH values from 3 to 9, the dissolved Fe²⁺ and the lattice Fe(Ⅱ) of siderite activate H₂O₂ to generate ·OH. An increase in siderite dosage and H₂O₂ concentration favored the generation of ·OH, but higher siderite dosage and H₂O₂ concentration suppressed the production rate. The inhibition order of anions on the generation of ·OH was confirmed as follows $C{l}^{-}$ > $N{O}_3^{-}$ > $S{O}_4^{2-}$. Little difference was observed in the presence of Ca²⁺ and Mg²⁺, while the presence of Mn²⁺ significantly promoted the production of ·OH. The suppression of humic acid (HA) became more serious as the HA concentration increased. Cycling experiments proved that the system could still produce ·OH in four cycles, although the production rate experienced a slight decrease. The experimental results suggested the role of siderite in the degradation of organic pollution in the process of in-situ soil and groundwater remediation.

[en] Highlights: • The new constructing 170 GHz/ 30 MW EC H&CD upper launcher of CFETR was briefly introduced. • A 3D visual quasi-optical design tool for the CFETR UL has been developed. • The focusing mirror of the quasi-optical system is designed as a mirror with two specific principal curvature radii. • The spot size of the multi-beam was optimized, which was converged in the resonance layer. • The heat loads on the focusing mirrors and steering mirror were analyzed. The China Fusion Engineering Test Reactor (CFETR) is the next-generation device for China magnetic controlled fusion program. A high power (36 MW) and continuous millimeter-wave injected by two Upper Launchers (ULs) are planned for Electron Cyclotron Heating and Current Drive (EC H&CD) in CFETR. A 3D visual quasi-optical design tool for the UL has been developed based on MATLAB that is capable of accurate visualization of beam propagations and the evaluations of quasi-optical system layout in the UL. One UL has two identical sets of quasi-optical modules, each one is mainly composed of nine fixed focusing mirrors and one flat steering mirror. By using the design tool to optimize the quasi-optical system for the UL, the minimum concentration radius (∼ 110 mm) of the nine mm-wave beams is obtained at the resonance layer. The evaluation results of the peak heat load on the FMs and SM obtained were 0.71 MW/m² and 1.46 MW/m², respectively.

[en] Pressure effects on the liner temperature of a syngas model combustor are studied by experimental and numerical methods, with an attempt to analyze the influence mechanism. The model combustor, fueled with 10 MJ/Nm"3 coal-derived syngas, is installed in a pressurized test-rig. Several diffusion flames with thermal powers up to 180 kw at pressures within 0.1–0.35 MPa are studied using a variety of measurement techniques. The liner temperature varies monotonically along the flow direction, and the maximum temperature appears around the dilution holes. Moreover, the liner temperature increases in the dilution zone but decreases in the primary zone with the increase of operating pressure, when the combustor exit temperature is maintained at 1073 K. Then, the combustion behaviors of the model combustor within pressure range of 0.1–2.0 MPa are simulated using CFD method, and the computed liner temperatures of testing cases agree well with the experimental data. The liner temperature varies approximately from −20 K to 150 K depending on locations when the pressure rises from 0.1 MPa to 2.0 MPa. It shows notable variation with operating pressure under low pressure conditions. However, as the operating pressure continues to increase, its impact on the liner temperature and the maximum temperature turns out to be very small. In order to explain the influence mechanism of operating pressure on the linear temperature, its effects on the flame structure, the liner heat flux, the convection and radiation are analyzed under different pressures. This study could be valuable for predicting and analyzing temperature distribution of the liner of gas turbine combustor. - Highlights: • The liner temperature of a combustor is studied within pressure range of 0.1–2.0 MPa. • The liner temperature increases with pressure in rear but deceases in head zones. • Peak temperature increases and flame is longer and narrower under higher pressure. • Nu augmentation ratio reduces and tends steady with pressure increase. • Radiation intensity of the liner tends to be steady under high pressure

[en] Highlights: • Constructed a multi-source data fusion model • Determined the list and distribution of potentially contaminated sites (PCS) in China • Presented an integrated assessment methodology for management of PCS • The methodology experimented successfully in China and offers a step towards ranking assessment of PCS globally. Ranking assessment of potentially contaminated sites (PCS) provides a great quantity of information (namely the risk screening list) that is usually examined by environmental managers, and therefore reduces the cost of risk management in terms of site investigation. Here we propose an integrated assessment methodology to establish a risk screening list of PCS in China using the Choquet integral correlation coefficient (ICC), which takes the uncertainty and interaction of PCS attributes into explicit account. The proposed method globally considers the importance and ordered positions of PCS attributes while reflecting their overall ranking. The model evaluation and actual validation results demonstrate the success in PCS ranking by the proposed method, which is superior to other methods such as the intuitionistic fuzzy multiple attribute decision-making, the technique for order preference by similarity to an ideal solution, and the weighted average. The resulting spatial distribution of Choquet ICC indicates that high-attention PCS in China are mainly located in Guangdong, Jiangsu, Zhejiang, and Shandong Provinces. This study is the first attempt to conduct a ranking assessment of PCS across China. The proposed assessment method based on Choquet ICC offers a step towards establishing a risk screening list of PCS globally.

[en] Highlights: • Emissions of a syngas combustor are studied within pressure range of 0.1–2.0 MPa. • NO_x shows parabolic profiles with pressure when primary T_a_d is below 1800 K. • NO_x keeps a power-law with pressure when primary T_a_d is above 1800 K. • Premixed burning mode and steam dilution show advantage in pollutant reducing. • NO_x emissions extremely increase with slight NH_3 existence in syngas. - Abstract: Pressure effects on NO_x and CO emissions of a model syngas combustor were experimentally and numerically studied. The validated numerical method was employed to analyze pressure effects on the combustor emissions such as different mixing levels and extra reactant addition. The model combustor, fueled with 10 MJ/N m"3 coal-derived syngas, was installed in a pressurized test-rig, and emissions were measured within 0.1–0.35 MPa. Based on the flow, temperature and species fields calculated by the CFD method, a chemical reactor network (CRN) model was established. With a detailed chemical scheme, the emissions calculated by the CRN model agreed well with experimental results. The model was then employed to calculate emissions within pressure range from 0.1 to 2.0 MPa, with the adiabatic flame temperature in the primary zone varied from 1477 to 2317 K. The calculated NO_x and CO emissions generally showed exponential relationship with the operating pressure, except that the NO_x emission decreased at higher pressure when the primary adiabatic flame temperature was lower than 1800 K. Through the analyses of the NO_x formation pathways, it was found that the higher pressure would generally enhance the N_2O pathway, which dominated NO_x formation at low temperature, but NO_x emission concentration through N_2O pathway decreased with pressure above 1.0 MPa at low temperature, which could explain the NO_x emission behavior. The CRN modeling method was applied to analyze the effects of pressure on emission behaviors under the different mixing modes and with the extra reactant such as H_2O and NH_3 in fuel. Premixed and steam dilution burning modes showed better performance on reducing emissions at elevated pressures. NH_3 could obviously increase the emission levels, especially at low pressure. Comprehensive understanding of the relationship between the emissions and the operating pressure in full pressure range was obtained, which could be valuable for the predicting and analyzing the syngas combustor pollutant emissions.