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Flexible Silica aerogel has a broad application prospect in the field of oil-water separation due to its low density and high porosity. However, its poor mechanical properties limit its application and it is a challenge to improve its mechanical properties while maintaining its excellent oil absorption capacity. In this work, we add silica sol to the silica source system formed by vinyltrimethoxysilane (VTMS) and vinylmethyl dimethoxysilane (VMDMS) to prepare silica sol-reinforced flexible silica aerogels by ambient pressure drying. The introduction of silica sol provides more -OH groups that can be used as condensation sites. The hydrolysis products of VTMS and VMDMS undergo dehydration condensation reaction with these exposed -OH groups and co-polymerize, resulting in a more robust three-dimensional porous structure. Silica sol- reinforced vinyl flexible silica aerogel is prepared with excellent mechanical properties. Its maximum strain can reach 80 % in 10 compression-decompression cycles without destroying its structure. Its hydrophobic angle was 145.7 °. Most particularly, compared to conventional flexible aerogel,when the silica sol-reinforced vinyl flexible silica aerogel is used in oil-water separation applications, it does not need to be dried after absorbing oil but only mechanically squeezed to expel the absorbed organic solvent. It can be reused hundreds of times, which greatly improves the efficiency of oil-water separation. • Progress and research directions of flexible silica aerogels are discussed. • The maximum compression of the aerogels can reach 80 % and the water contact angle can reach 145.7°. • The prepared flexible aerogels still has excellent mechanical properties after oil absorption. • Various methods for oil-water separation using flexible aerogels are proposed. [ABSTRACT FROM AUTHOR]

• Bactrocera dorsalis is an invasive agricultural pest with strong flight capability. • This study is a novel approach in quantification of JH in flight muscle using HPLC. • JH titer varies with age and sex, increases flight activity and higher post-flight. • Females have higher JH titers than males for ovarian and flight muscle development. • JH and flight activity have a mutually reinforcing relationship. The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is considered a major economic threat in many regions worldwide. In order to better understand the flight capacity of B. dorsalis and its physiological basis, the functions and regulatory roles of juvenile hormone (JH) in the flight muscle of B. dorsalis were studied under a controlled environment. JH titer of B. dorsalis varied with age and sex. Females have higher JH titers and better flight capabilities than males, given that the increase in JH also corresponded to the ovarian development and maturation in females. The flight duration and distance of both males and females increased with the gradual increase of JH titer after adult emergences. Both JH titer and flight capability peaked in 15-d-old adult and declined subsequently with age. Flight activity stimulated the production of JH as adults flown for 24 h on the flight mills have the highest JH titers compare to adults flown on shorter flight durations. Adults treated with 0.5 µg and 5 µg of JH III were able to fly long durations and long distances, nevertheless when JH titer was too low or too high, it would restrict the flight ability of the fly. The mutual reinforcement of JH and flight activity provides fundamental understanding on the physiological aspects of the flight capability and dispersal, which facilitates strategies for the long-term control of this destructive pest. [ABSTRACT FROM AUTHOR]

The flow behavior of high-temperature ash (HTA) and low-temperature ash (LTA) of high calcium coal in the heating process was investigated systematically. By means of the heating stage microscope, the behavioral changes of samples were studied visually. The composition and mineral matters transformations of HTA and LTA samples were analyzed by X-ray fluorescence and X-ray diffraction. The results show that the original composition of HTA sample is different from that of LTA sample. In addition, the HTA and LTA samples experience the shrinkage, fusion and spreading processes in succession. However, the volume change of HTA sample is different from that of LTA sample. The volume of LTA sample shows a slow change at the temperature lower than 800 °C, while the volume of HTA sample is unchanged. In the temperature range of 800°C–1100 °C, the remarkable shrinkage of HTA and LTA samples are demonstrated. The formation of srebrodolskite and gehlenite attributes to this volume change. Moreover, the sharp shrinkage of HTA and LTA samples is indicated at 1100°C–1300 °C. This is caused by the formation of eutectics. Because of the diverse content and species of mineral matters in LTA sample, the volume change of LTA sample is more remarkable than that of HTA sample. The maximal shrinkages of LTA and HTA sample are 57% and 53%, respectively. • The flow behavior of HTA and LTA samples was investigated. • The mineral matters transformations of HTA and LTA samples were illustrated. • The LTA sample show the slow shrinkage in the lower temperature. • The formation of srebrodolskite and gehlenite attributes to change at 800°C–1100 °C. • The maximal shrinkages of LTA and HTA sample are 57% and 53%, respectively. [ABSTRACT FROM AUTHOR]

Silica aerogels are attractive oil-absorbing agents due to their low density, high porosity. However, how to discharge the oil which adsorbed by silica aerogels is a difficult issue. To address this challenge, new separation strategies with high efficiency are needed. In this study, we prepared the temperature and pH dual response flexible silica aerogel have temperature response and pH response effect, which can change its wettability by adjusting temperature or pH. On the one hand, the temperature and pH responsive flexible silica aerogel can be used to adsorb water at the temperature below 34.73 °C or pH > 7. On the other hand, it can adsorb oil at a temperature above 34.73 °C or pH < 7. The automatic desorption of oil can be achieved without consuming additional energy and damaging the pore structure. Therefore, the sample could continuously adsorb and filtrate efficiently and realize the recovery of oil and adsorption materials. [Display omitted] • Temperature and PH dual response flexible silica aerogel was prepared by introducing isopropylacrylamide and sodium alginate. • Maximum strain of the sample is high as 80% and the size can be recoverable completely without destruction of internal and external structures. • The sample can change its wettability by adjusting temperature or pH to adsorb water at the temperature below 30°C or pH>7 and adsorb oil at a temperature above 34.73°C or pH<7. • The sample can realize automatic desorption of oil without consuming additional energy and damaging the pore structure. It has great prospects in the filtration and adsorption of oil/water separation. [ABSTRACT FROM AUTHOR]

The metal-oxide-semiconductor high-electron-mobility transistors (MOS HEMTs) have been demonstrated and compared with the conventional unpassivated AlGaN/GaN HEMTs. 20 nm SiO 2 layer deposited by PECVD (plasma enhanced chemical vapor deposition) is used as a gate-insulator in the SiO 2 /AlGaN/GaN MOS HEMT. We present empirical evidence that MOS HEMTs outperforms the conventional HEMTs with DC performance. The piezotronic effect is then introduced to modulate the drain current of HEMTs by applying external stresses on the devices. The saturated drain currents of the HEMT devices decrease under in-plane tensile strain which is resulted from the piezoelectric polarization effect at the AlGaN/GaN interface. Working mechanism of the piezotronic effect modulating properties of 2DEG (two dimensional electron gases) and electrical transportation behavior of the HEMT devices are conducted via the band energy profile in the AlGaN/GaN heterstructure. 3D strain model is also induced to simulate and illustrate the proposed working mechanism further. This study provides in-depth comprehension into working principle of the piezotronic effect modulating physical properties of 2DEG in AlGaN/GaN hetero structures as well as guidance for the potential application in HEMT and MEMS/NEMS devices. [ABSTRACT FROM AUTHOR]

Li-S batteries, though promising for long-distance electrical vehicles, are still not practically viable mainly due to the short cycling life arising from the polysulfide shuttle. Herein, we demonstrate a Li/polysulfide battery with 3D nitrogen-doped reduced graphene oxide (rGO)/carbon nanotube (CNT) hybrid aerogel as the binder-free and self-standing host for liquid polysulfide-containing catholyte. Hetero-dopants of nitrogen and CNT additives are found to significantly improve the electrochemical performances due to the abundant active catholyte/electrolyte interfaces, high rate charge-transfer paths, and spatially uniform depositing/stripping of reactants. The final hybrid aerogel achieves long cycling stability (0.11% capacity fading rate for 400 cycles) and high rate capability (767 mAh/g sulfur at 2 C rate) at a high areal sulfur loading weight of ~6 mg/cm 2 . [ABSTRACT FROM AUTHOR]

With enhanced light output efficiencies, InGaN/GaN micro-disk LED has received intensive attentions recently. Combining isotropic and anisotropic dry etching processes, an innovative semi-floating InGaN/GaN micro-disk LED array is fabricated, which shows remarkable light intensity enhancement up to 150% compared to the broad-base LED. A systematic study of micro-spectrums and Poisson-Schrodinger coupling self-consistent calculation reveal that there is non-uniform residual stress distribution on the micro-disk LED. Along micro-disk center to micro-disk edge, as the Si substrate is etched off, the in-plane tensile stress in the GaN layer reduces, while the compressive stress in InGaN layer increases gradually. This gradient stress distribution has caused a non-uniform piezo-phototronic effect in the micro-disk LED, which in turn results in a maximum wavelength shift of 16 meV for the light emitted along micro-disk center to micro-disk edge. This study not only opens research of flexo-optoelectronic effect, e.g. non-uniform piezo-phototronic effect, in complex micro/nano optoelectronic/electronic devices, but also provides important guidance for the significant enhancement of light emission efficiency in micro-disk LEDs. An innovative semi-floating InGaN/GaN micro-disk LED array is fabricated by combining the isotropic and anisotropic dry etching processes. It has a significant intensity increase reaching up to 150% compared to broad-base LED. For the first time, we reveal non-uniform piezo-phototronic effect in complex micro optoelectronic devices through spatial micro-spectrums and Poisson-Schrodinger coupling self-consistent calculation, which caused by the gradient in-plane stress distribution with the lift-off of Si substrate. Image 1 • Semi-floating InGaN/GaN/Si micro-disk LED arrays are fabricated by combining isotropic and anisotropic etching processes. • Semi-floating micro-disk LEDs show an enhanced light intensity up to 150% compared to broad-base LEDs. • Non-uniform piezo-phototronic effect has been formed in the micro-disk LED caused by the gradient stress distribution. [ABSTRACT FROM AUTHOR]

Abstract: Phase equilibria for the K2O–Al2O3–H2O system were investigated at 40°C. In the concentrated alkali region of the phase diagram, only the equilibrium solid-phase K2O·Al2O3·3H2O was found besides KOH·H2O. This is different from the fact of the similar system Na2O–Al2O3–H2O. Two invariant points with their respective equilibrium solid pairs (Al2O3·3H2O versus K2O·Al2O3·3H2O and K2O·Al2O3·3H2O versus KOH·H2O) were identified with their corresponding compositions. These findings can provide a significant database for the removal of alumina from the concentrated alkali solution that was produced in the cleaner manufacturing process for chromium compounds. [Copyright &y& Elsevier]

The fusibility characteristics and flow properties of the biomass and biomass-coal ash samples were investigated in this paper. Ash fusibility of the biomass-coal blended samples was evaluated systematically. The mineral matters variation and liquidus temperature of the biomass-coal blended samples were demonstrated by FactSage. The results show that the ash fusion temperature of biomass-coal blended samples decreases and then increases with the increasing content of biomass (straw). The ash fusion temperature reaches the minimum when straw content is 50%. Moreover, the liquidus temperature reflected in the phase diagram can predict the variation of ash fusion temperature well. Furthermore, the flow properties of high temperature ash (HTA) and low temperature ash (LTA) straw samples at different atmosphere were observed using the heating stage microscope. In the heating process, the HTA and LTA straw samples show the similar variation: shrinkage, fusion and spreading. However, the volume changes of the HTA and LTA straw samples are different considerably attributing to the mineral matters variation. It was revealed that the volume change of HTA and LTA straw samples is not obvious at the lower temperature. For the LTA straw sample in air atmosphere, the maximal volume change is obtained. • The flow behavior of straw ashes at different atmosphere was investigated using heating stage microscope. • For LTA straw sample in air atmosphere, the volume change reaches the maximum. • The atmosphere has greater influence on the HTA straw sample. • The duration time of fusion process in the vacuum atmosphere is longer. • The ash fusion temperature of the blended samples reaches the minimum when the straw content is 50%. [ABSTRACT FROM AUTHOR]

We propose a new method for fabricating large-scale uniform high-quality submicron inverted pyramid pit arrays by laser interference lithography (LIL), combined with dry etching and wet etching. In this process, uniform photoresist dot arrays are fabricated by LIL for 2-inch wafer. Dry etching is used to ensure the formation of the fluorocarbon organic polymer (FOP) mask layer. Wet etching parameters are investigated in details and inverted pyramid pits with {111} sidewalls are formed by anisotropic wet etching. Using this method, we have successfully produced uniform high-quality inverted pyramid pit arrays with the average size of 240 nm and the period of 450 nm. The size of pits can be tailored between 200 nm and 400 nm and the size deviation of inverted pyramid pits is 6.7% over the whole 2-inch wafer. This method offers a simple, less time consuming and cost-effective process of micro-nano pattern fabrication. Besides, GeSi QDs are quantitatively investigated by a nucleation model which shows GeSi QDs are preferentially grown at the tip of inverted pyramid pit and four intersection lines of two {111} planes inside the pit. • Fabricating submicron inverted pyramid pit arrays by laser interference lithography. • The mask layer of wet etch is fluorocarbon organic polymer caused by dry etch. • The size deviation of prepared patterns is 6.7% over 2-inch wafer. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highest yield (74%) of CNCs were obtained by mathematical orthogonal experiment design. • One-step hybrid preparation of CNCs/SiO 2 aerogel is a relatively innovative idea. • The adsorption capacity of CNCs/SiO 2 aerogel for MB is slightly higher than other similar materials. • The removal rate of MB adsorbed by aerogels remained above 60% after 5 adsorption cycles. Using cheap sodium silicate as raw material, a novel composite aerogel of self-assembled cellulose nanocrystals (CNCs)/SiO 2 was successfully prepared by freeze-drying method, which can effectively to adsorb methylene blue (MB) pollutants in water and reduce the burden on the water environment. By investigating the effects of mass fraction of sulfuric acid, hydrolysis temperature, hydrolysis time and liquid–solid ratio on hydrolysis yield, the maximum CNCs yield (74%) obtained from orthogonal experiment was designed. The morphology, important functional groups and key structural elements of the aerogel were characterized by SEM, FTIR and XPS, respectively. Meanwhile, the mesoporous structure of the aerogel was analyzed by BET test, and it was found that its specific surface area could reach 440.715 m2/g. Besides, the adsorption results for MB showed that the Langmuir isotherm model and the pseudo-second order model can better fit the experimental data well with a maximum adsorption capacity of 190.85 mg/g. Adsorption thermodynamics study reveals that the adsorption process is spontaneous and endothermic. Hence, the findings of this research offer a more market application prospect for the composite aerogel, and provide a certain reference basis for the dye wastewater treatment. [ABSTRACT FROM AUTHOR]

Preparation of high specific surface area activated carbon from rice husk for the removal of ofloxacin from medical wastewater. The optimum conditions for the preparation of activated carbon were a nitrogen doping ratio of 1:1:4 and an activation temperature of 800 °C (AC). The samples were characterised by N 2 adsorption isotherms, BET, FT-IR, TGA, XPS and SEM. The data showed that the specific surface area of AC was up to 1818.20 m2 g−1 with a total pore volume of 1.12 cm3 g−1. AC formed N-containing functional groups on the surface and had good thermal stability. Scientific batch experiment studies were conducted to investigate the effect of pH, initial concentration, temperature and coexisting ions on the ofloxacin adsorption. The q e reached a maximum value of 780 ± 20 mg g−1 and maintained a removal efficiency of 51.1% after four regeneration cycles. The adsorption equilibrium data and the adsorption process were well represented by Langmuir model and general-order kinetic model, respectively. Thermodynamic studies of adsorption had shown that the adsorption process was autogenous and endothermic. Possible adsorption mechanisms for this material were also analysed. Finally, treatment of synthetic medical wastewater with AC resulted in a high removal rate of 98.3%. The superior adsorption properties combined with ease of preparation, ease of separation and excellent regeneration properties, make this material potentially effective for the removal ofloxacin from real medical wastewater. [Display omitted] • Optimal preparation conditions for N-doped AC were studied. • The maximum sorption capacity of AC was 780 mg g−1. • Various mechanisms for efficient adsorption of N-doped AC were analyzed. • Removal of ofloxacin from synthetic medical wastewater. [ABSTRACT FROM AUTHOR]

The growth technology of GaN-based light-emitting-diodes (LEDs) greatly restricts their preparation of vertical structure. Now we can get GaN-based LEDs structure on silicon (Si) substrate, which makes us a big step forward in the preparation of vertical GaN-based LEDs. Herein, we report the fabrication of vertical GaN-based LEDs through a chemical etching process to removing Si substrate combing with inductively coupled plasma reactive ion etching (ICP-RIE) to remove the un-doped buffer followed by copper (Cu) electroplating technology. By collecting photoluminescence (PL) and Raman scattering spectra of the GaN-based epitaxial structure, it is confirmed that the residual strain between the epitaxial structure and growth substrate is effectively released. The corresponding electroluminescence (EL) measurement of the vertical GaN-based LEDs was conducted by using a probing test with an optical power meter, showing a good electrical property and optical property. The vertical GaN-based LEDs have better output power and better heat dissipation capacity. This research proposes a low-cost method to fabricate freestanding and high performance vertical GaN-based LEDs. • High power vertical structure LED is fabricated by removing the Si substrate and preparing new copper substrate by electroplating. • After removing the substrate, the whole work was carried out on a very thin epitaxial film. • In this experiment, a good epitaxial film was still obtained after ICP etching. • Without high temperature and high-pressure processing, electroplating can avoid damaging the materials. • This study offers great promise for new optoelectronic device configurations and future flexible photonic devices. [ABSTRACT FROM AUTHOR]