Multilayer stacked ultra-wideband perfect solar absorber and thermal emitter based on SiO2-InAs-TiN nanofilm structure.

In this paper, a broadband solar absorber is constructed and simulated based on the finite difference time domain method (FDTD). The modeled structure of the absorber consists of cyclic stacking of five absorber cells with different periods on refractory metal W, where a single absorber cell is composed of a three-layer SiO2-InAs-TiN square film. Due to the Fabry-Perot resonance and the surface plasmon resonance (SPR), an absorptivity greater than 90% within a bandwidth of 2599.5 nm was achieved for the absorber. Notably, one of these bands, 2001 nm, is a high-efficiency absorption with an absorption rate greater than 99%. The average absorption efficiency reaches 99.31% at an air mass of 1.5 (AM 1.5), and the thermal radiation efficiencies are 97.35% and 97.83% at 1000 K and 1200 K, respectively. At the same time, the structure of the absorber is also polarization-independent, and when the solar incidence angle is increased to 60°, it still achieves an average absorption of 90.83% over the entire wavelength band (280 nm to 3000 nm). The novelty of our work is to provide a design idea based on a unit structure with multiple cycles, which can effectively expand the absorption bandwidth of the absorber in the visible-near-infrared wavelengths. The excellent performances make the structure widely used in the field of solar energy absorption.

Influence of the first wave of COVID-19 on Chinese students' psychology and behavior: a case study approach.

During the first wave of COVID-19, China demonstrated a strong commitment to epidemic prevention and control. This case study focuses on Z University, which adopted closed management when the epidemic was serious, and examines the influence of COVID-19 on students' psychology and behavior through interviews with 10 students. The research reveals that while students perceive closed management during the epidemic as enhancing safety and promoting learning engagement to some extent, the epidemic also has adverse effects on their physical health, psychology, and social life. These impacts included deteriorating physical health, feelings of rebellion and depression regarding college life, alongside concerns and aspirations regarding future job stability. In the discussion, we suggest that higher education institutions can utilize this information to shape policies and procedures, particularly concerning mental health and risk communication, not only during the current pandemic but also in future emergency or disaster scenarios.

A novel highly dispersed calcium silicate hydrate nanosheets for efficient high-concentration Cu2+ adsorption.

Currently, the low cost and effective purification toward heavy metal ions in wastewater has garnered global attention. Herein, we used hydrothermal method to prepare highly dispersed calcium silicate hydrate in fluorite tailings. And the stacking thickness of calcium silicate hydrate layered morphology was less than 5 nm. For high concentration Cu2+ purification investigation in wastewater, we found that the equilibrium adsorption capacity reached 797.92 mg/g via the CSH with 3:2 Ca/Si molar ratio, be 1.43-21.8 times than that of reported data. Therein, the metal-metal exchange and deposition are the primary pathways for Cu2+ adsorption, and electrostatic attraction is the secondary pathway. And the relative ∼100 % removal rate of high-concentration Ni2+ and Cr3+ ions were confirmed via CSH prepared from different tailings. This method offers a cost-effective way to utilize tailings for preparing highly efficient adsorbents toward HMIs removal in wastewater.

Clay minerals/sodium alginate/polyethylene hydrogel adsorbents control the selective adsorption and reduction of uranium: Experimental optimization and Monte Carlo simulation study.

Clay minerals formations are potential geological barrier (host rocks) for the long-rerm storage of uranium tailing in deep geological repositories. However, there are still obstacles to the efficient retardation of uranium because of the competition between negatively charged regions at the clay minerals end face, surface and between layers, as well as low mineralization capacity. Herein, employing a simple method, we used sodium alginate (SA), an inexpensive natural polymer material, polyethylene (PE), and the natural clay minerals montmorillonite (Mt), nontronite (Nt), and beidellite (Bd) to prepare three hydrogel adsorbents, (denoted as Mt/PE-@SA, Nt/PE-@SA, and Bd/PE-@SA), respectively. The application of obtained hydrogel adsorbents further extends to uranium(VI) removal from aqueous. Due to the synergistic action of SA group and PE group, hydrogel adsorbents showed select adsorption and mineralization effect on uranium(VI), among which the maximum uranium(VI) adsorption capacity of Nt/PE-@SA was 133.3 mg·g-1 and Mt/PE-@SA exhibited strong selectivity for uranium(VI) in the presence of coexisting metal ions. Cyclic voltammetry studies indicated the mitigation and immobilization of uranium species onto adsorbents by both reduction and mineralization. Besides, the synergistic adsorption of SA and PE on clay minerals was hypothesized, and the idea was supported by structure optimizations results from Monte Carlo dynamics simulation (MCD). Three obtained hydrogel adsorbents structural model was constructed based on its physicochemical characterization, the low energy adsorption sites and adsorption energies are investigated using MCD simulation. The simulation results show that obtained hydrogel adsorbents have a strong interaction with uranium(VI), which ensures the high adsorption capacity of those materials. Most importantly, this work demonstrates a new strategy for preparing mineral-based hydrogel adsorbents with enough stability and provides a new perspective for uranium(VI) removal in complex environment.

MD-DFT Calculations on Dissociative Absorption Configurations of FOX-7 on (001)- and (101)-Oriented Crystalline Parylene Protective Membranes.

Crystalline poly-para-xylylene (parylene) has the potential for use as a protective membrane to delay the nucleation of explosives by separating the explosives and their decomposition products to decrease the explosive sensitivity. Here, molecular dynamics (MD) and density functional theory (DFT) techniques were used to calculate the dissociative adsorption configurations of 1,1-diamino-2,2-dinitroethylene (FOX-7) on (001)- and (101)-oriented crystalline parylene membranes. Based on the results of the calculations, this work demonstrates that the -NO2-π electrostatic interactions are the dominant passivation mechanism of FOX-7 on these oriented surfaces. FOX-7 can dissociatively adsorb on oriented parylene membranes due to the interactions between the LUMO of the toluene (or methyl) groups on parylene and the HOMO of the -NO2 (or -NH2) groups on FOX-7. The formation of a new intermolecular H-bond with the ONO group leads to FOX-7 decomposition via intramolecular C-NO2 bond fission and nitro-to-nitrite rearrangement. The most likely adsorption configurations are described in terms of the decomposition products, surface active groups of parylene, binding behaviors, and N charge transfer. Importantly, the (001)-oriented parylene AF8 membrane is promising for use as a protective membrane to passivate the high-energy -NO2 bonds during the dissociative adsorption of FOX-7. This study offers a new perspective on the development of protective membranes for explosives.

Ligand Engineering Enables Efficient Pure Red Tin-Based Perovskite Light-Emitting Diodes.

With increasing ecological and environmental concerns, tin (Sn)-based perovskite light-emitting diodes (PeLEDs) are competitive candidates for future displays because of their environmental friendliness, excellent photoelectric properties, and low-cost solution-processed fabrication. Nonetheless, their electroluminescence (EL) performance still lags behind that of lead (Pb)-based PeLEDs due to the fast crystallization rate of Sn-based perovskite films and undesired oxidation from Sn2+ to Sn4+ , leading to poor film morphology and coverage, as well as high density defects. Here, we propose a ligand engineering strategy to construct high-quality phenethylammonium tin iodide (PEA2 SnI4 ) perovskite films by using L-glutathione reduced (GSH) as surface ligands toward efficient pure red PEA2 SnI4 -based PeLEDs. We show that the hydrogen-bond and coordinate interactions between GSH and PEA2 SnI4 effectively reduce the crystallization rate of the perovskites and suppress the oxidation of Sn2+ and formation of defects. The improved pure red perovskite films not only show excellent uniformity, density, and coverage but also exhibit enhanced optical properties and stability. Finally, state-of-the-art pure red PeLEDs achieve a record external quantum efficiency of 9.32 % in the field of PEA2 SnI4 -based devices. This work demonstrates that ligand engineering represents a feasible route to enhance the EL performance of Sn-based PeLEDs.

Experimental Study of Dynamic Tensile Strength of Steel-Fiber-Reinforced Self-Compacting Concrete Using Modified Hopkinson Bar.

As a typical brittle material, the tensile strength of concrete is much lower than its compressive strength. The main failure mode of concrete buildings under explosive and impact loading is spalling, so it is crucial to understand the dynamic tensile performance of concrete. This paper presents an experimental study on the dynamic tensile strength of steel-fiber-reinforced self-compacting concrete (SFRSCC). Specimens of two different self-compacting concrete (SCC) mixes (C40 and C60) and four different fiber volume fractions (0.5%, 1.0%, 1.5%, and 2.0%) are fabricated. Dynamic tensile strengths of SFRSCC are obtained using a modified Hopkinson bar system. The relationships between the dynamic tensile strength of the corresponding SCC mix, the quasi-static compressive strength, and the fiber volume fraction are discussed. An empirical equation is proposed. It is shown that SFRSCC with high compressive strength has higher dynamic tensile strength than low-strength SFRSCC for the same fiber content, and the dynamic tensile strength of SFRSCC possesses an approximately linear relation with the fiber volume fraction. The mechanism underlying this fiber-reinforcement effect is investigated.

Dynamically changeable terahertz metamaterial absorbers with intelligent switch and high sensitivity and wide and narrow band perfect absorption.

In this work, we theoretically designed a dynamically changeable terahertz metamaterial absorber with intelligent switch and high sensitivity, wide band and narrow band perfect absorption based on the combination of Dirac semimetal (BDS) and vanadium dioxide (VO2). It features two methods for absorption adjustment: altering the Fermi energy level of BDS to modify the resonant frequency of the absorption peaks and utilizing the phase change of VO2 to regulate the absorption rate of the peaks. In addition, its rotational symmetric design ensures strong polarization-insensitivity. The simulation results demonstrate the presence of two narrowband absorption peaks and one mini-broadband absorption peak within the frequency range of 6.0-9.5 THz, all with absorption rates exceeding 90%. We provide an explanation of the absorption mechanism of the device, employing the relative impedance theory and localized surface plasmon resonance to analyze its electric field distribution. We also defined the refractive index sensitivity (S), which is SI = 378 GHz per RIU and SIII = 204 GHz per RIU. Our device possesses high sensitivity and two methods of adjusting absorption modes, which endow it with advantages in the fields of metamaterial absorbers, intelligent switch, and optical sensors.

Active thermally tunable and highly sensitive terahertz smart windows based on the combination of a metamaterial and phase change material.

A thermally tunable terahertz window based on the combination of a metamaterial and the phase change material VO2 is proposed. The window is composed of two vanadium oxide films with a SiO2 layer sandwiched between them. The thermochromic phase change properties of VO2 are the key to the functionality of the window. By controlling the temperature around the room temperature of 300 K, our material can be used as a smart window and it is able to regulate both the absorption and transmission of external terahertz waves in response to changes in temperature. The absorbance can be regulated by more than 90% and the transmittance by more than 80%. The switching characteristics of the window are explained by the insulator-metal transition that vanadium oxide undergoes during the heating process, while localized surface plasmon resonance explains the perfect absorption. In addition, the designed window is not only insensitive to polarised waves, but is thermally flexible and maintains excellent performance over a wide angular range of 0° to 40°. This design will have significant potential for applications in stealth technologies, thermal sensing and switching, and terahertz energy harvesting.

Mineralogy and phase transition mechanisms of atmospheric mineral particles: Migration paths, sources, and volatile organic compounds.

Inorganic mineral particles play an important role in the formation of atmospheric aerosols in the Sichuan Basin. Atmospheric haze formation is accompanied by the phase transition of mineral particles under high humidity and stable climatic conditions. Backward trajectory analysis was used in this study to determine the migration trajectory of atmospheric mineral particles. Furthermore, Positive matrix factorization (PMF) was used to analyze the sources of atmospheric mineral particles. The phase transition mechanisms of atmospheric mineral particles were studied using ion chromatography, inductively coupled plasma emission spectrometry, total organic carbon analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy coupled with energy dispersive spectrometry, and grand canonical Monte Carlo methods. Three migration and phase transition paths were identified for the mineral particles. Sources of atmospheric mineral particles included combustion, vehicle emissions, industrial emissions, agricultural sources, and mineral dust. The main mineral phases in atmospheric particles, calcite and dolomite, were transformed into gypsum, and muscovite may be transformed into kaolinite. The phase transition of mineral particles seriously affects the formation of aerosols and worsens haze. Typically, along the Nanchong-Suining-Neijiang-Zigong-Yibin path, calcite is converted into gypsum under the influence of man-made inorganic pollution gases, which worsen the haze conditions and cause slight air pollution for 3-5 days. However, along the Guangyuan-Mianyang-Deyang-Chengdu-Meishan-Ya'an path, anthropogenic volatile organic compounds (VOCs) hindered gypsum formation from dolomite. Furthermore, dolomite and VOCs formed stable adsorption systems (system energies from -0.41 to -4.76 eV, long bonds from 0.20 to 0.24 nm). The adsorption system of dolomite and m/p-xylene, with low system energy (-1.46 eV/-1.33 eV) and significant correlation (r2 = 0.991, p < 0.01), was the main cause of haze formation. Consequently, calcite gypsification and dolomite--VOC synergism exacerbated regional haze conditions. This study provides a theoretical reference for the mechanism of aerosol formation in basin climates.

High confidence plasmonic sensor based on photonic crystal fibers with a U-shaped detection channel.

In order to improve the performance of optical fiber sensing and expand its application, a photonic crystal fiber (PCF) plasmonic sensor with a U-shaped channel based on surface plasmon resonance (SPR) is proposed. We have studied the general influence rules of structural parameters such as the radius of the air hole, the thickness of the gold film and the number of U-shaped channels using COMSOL based on the finite element method. The dispersion curves and loss spectrum of the surface plasmon polariton (SPP) mode and the Y-polarization (Y-pol) mode as well as the distribution of the electric field intensity (normE) under various conditions are studied using the coupled mode theory. The maximum refractive index (RI) sensitivity achieved in the RI range of 1.38-1.43 is 24.1 µm RIU-1, which corresponds to a full width at half maximum (FWHM) of 10.0 nm, a figure of merit (FOM) of 2410 RIU-1 and a resolution of 4.15 × 10-6 RIU. The results show that the proposed sensor combines the SPR effect, which is extremely sensitive to changes in the RI of the surrounding medium and realizes real-time detection of the external environment by analyzing the light signal modulated by the sensor. In addition, the detection range and sensitivity can be extended by adjusting the structural parameters. The proposed sensor has a simple structure with excellent sensing performance, which provides a new idea and implementation method for real-time detection, long-range measurement, complex environment monitoring and highly integrated sensing, and has a strong potential practical value.

FTO-dependent m6A modification of Plpp3 in circSCMH1-regulated vascular repair and functional recovery following stroke.

Vascular repair is considered a key restorative measure to improve long-term outcomes after ischemic stroke. N6-methyladenosine (m6A), the most prevalent internal modification in eukaryotic mRNAs, functionally mediates vascular repair. However, whether circular RNA SCMH1 (circSCMH1) promotes vascular repair by m6A methylation after stroke remains to be elucidated. Here, we identify the role of circSCMH1 in promoting vascular repair in peri-infarct cortex of male mice and male monkeys after photothrombotic (PT) stroke, and attenuating the ischemia-induced m6A methylation in peri-infarct cortex of male mice after PT stroke. Mechanically, circSCMH1 increased the translocation of ubiquitination-modified fat mass and obesity-associated protein (FTO) into nucleus of endothelial cells (ECs), leading to m6A demethylation of phospholipid phosphatase 3 (Plpp3) mRNA and subsequently the increase of Plpp3 expression in ECs. Our data demonstrate that circSCMH1 enhances vascular repair via FTO-regulated m6A methylation after stroke, providing insights into the mechanism of circSCMH1 in promoting stroke recovery.

Regulation of Glial Function by Noncoding RNA in Central Nervous System Disease.

Non-coding RNAs (ncRNAs) are a class of functional RNAs that play critical roles in different diseases. NcRNAs include microRNAs, long ncRNAs, and circular RNAs. They are highly expressed in the brain and are involved in the regulation of physiological and pathophysiological processes of central nervous system (CNS) diseases. Mounting evidence indicates that ncRNAs play key roles in CNS diseases. Further elucidating the mechanisms of ncRNA underlying the process of regulating glial function that may lead to the identification of novel therapeutic targets for CNS diseases.

Comparison of microscopic adsorption characteristics of Zn(II), Pb(II), and Cu(II) on kaolinite.

In this research, kaolinite was used to investigate the comparative adsorption of copper, lead, and zinc ions through batch control experiments and first principles calculations. Different adsorption conditions were considered as the effect of solution acidity, initial concentration of ions, and contact shaking time. The adsorption system isotherms and kinetic studies were better agreed with the Langmuir and pseudo-second-order kinetic models. They reached adsorption equilibrium within two hours and maximum adsorption capacities of Zn(II), Pb(II), and Cu(II) on kaolinite were 15.515, 61.523, and 44.659 mg/g, respectively. In addition, the microscopic adsorption changes of Zn(II), Pb(II), and Cu(II) on kaolinite were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy with energy dispersive X-ray spectroscopy. The results showed that Zn(II), Pb(II), and Cu(II) were most likely to be adsorbed on the kaolinite surface. Furthermore, the adsorption mechanism of [Zn(OH)]+, [Pb(OH)]+, and [Cu(OH)]+ on the kaolinite (001) surface was systematically studied through first-principles density functional calculations. The adsorption characteristics of different ions were evaluated by calculating the adsorption energy of the equilibrium adsorption configuration, state density, and electron density. The adsorption energy of [Zn(OH)]+, [Pb(OH)]+, and [Cu(OH)]+ were - 0.49, - 1.17, and - 1.64 eV, respectively. The simulation results indicated that new hybrid orbitals were formed between the metal ions and O atoms on the kaolinite surface, with electron transfer occurring the adsorption processes. The charge transfer direction for [Pb(OH)]+ was opposite those for [Zn(OH)]+ and [Cu(OH)]+. [Zn(OH)]+ was more likely to form polydentate complexes with hydroxyl groups on the kaolinite surface than [Cu(OH)]+ and [Pb(OH)]+. This work further elucidated the interaction mechanism between the adsorption systems and provided fundamental theoretical support for the structural modification and optimization of kaolinite, such as increasing the layer spacing of kaolinite and introducing other active groups on its surface to improve the adsorption capacity of heavy metal ions in water treatment and soil remediation.

Effect of Siderophore DFOB on U(VI) Adsorption to Clay Mineral and Its Subsequent Reduction by an Iron-Reducing Bacterium.

Uranium mining and nuclear fuel production have led to significant U contamination. Past studies have focused on the bioreduction of soluble U(VI) to insoluble U(IV) as a remediation method. However, U(IV) is susceptible to reoxidation and remobilization when conditions change. Here, we demonstrate that a combination of adsorption and bioreduction of U(VI) in the presence of an organic ligand (siderophore desferrioxamine B, DFOB) and the Fe-rich clay mineral nontronite partially alleviated this problem. DFOB greatly facilitated U(VI) adsorption into the interlayer of nontronite as a stable U(VI)-DFOB complex. This complex was likely reduced by bioreduction intermediates such as the Fe(II)-DFOB complex and/or through electron transfer within a ternary Fe(II)-DFOB-U(VI) complex. Bioreduction with DFOB alone resulted in a mobile aqueous U(IV)-DFOB complex, but in the presence of both DFOB and nontronite U(IV) was sequestered into a solid. These results provide novel insights into the mechanisms of U(VI) bioreduction and the stability of U and have important implications for understanding U biogeochemistry in the environment and for developing a sustainable U remediation approach.

Mori Fructus Polysaccharides Attenuate Alcohol-Induced Liver Damage by Regulating Fatty Acid Synthesis, Degradation and Glycerophospholipid Metabolism in Mice.

Mori Fructus polysaccharides (MFP) are macromolecules extracted from Mori Fructus (MF), which has the biological activity of anti-liver damage. Our group found that MFP maybe down regulate the serum triglyceride level in mice with alcohol-induced liver damage, suggesting that MFP can regulate lipid metabolism, but its specific mechanism is still not clear. Fifty SPF-ICR male mice weighing 18-22 g were randomly divided into five groups, blank group, model group, bifendate group, MFPA1 group and MFPB1 group. The blood and liver tissues were taken from mice for nontargeted lipidomic analysis and histopathological examination after 7 day's treatment. The histopathological changes indicated that the normal liver cells were intact and regular, with orderly arrangement and distinct cell boundaries; the liver of model mice showed inflammatory infiltration, ballooning degeneration in the cells and small lipid drops; the liver of mice in the bifendate, MFPA1 and MFPB1 groups showed similar symptoms to those of model mice, but the lesions were less severe and the ballooning degeneration were reduced. Multivariate analysis of all lipids in the serum of five groups of mice showed there were obvious differences in lipid metabolism between the model group and the blank group. At the same time, seven kinds of differential lipids were precisely identified after screening, including prostaglandins, long-chain fatty acids, glycerophospholipids, acyl carnitines. In summary, alcohol intake and MFP intervention have significant effects on fatty acid synthesis, degradation and glycerophospholipid metabolism.

Untargeted lipidomics analysis of Mori Fructus polysaccharide on acute alcoholic liver injury in mice using ultra performance liquid chromatography-quadrupole-orbitrap-high resolution mass spectrometry.

ETHNOPHARMACOLOGICAL RELEVANCE: Mori Fructus (MF) is a traditional Chinese medicine with long application history, which has protective effects on liver diseases. Mori Fructus polysaccharide (MFP) is one of the active ingredients of MF and possesses therapeutic effects against acute alcoholic liver injury. Recent researches have reported that the therapeutic effects of MFP might be related to the regulation of several lipid metabolic pathways. However, the mechanism of lipid metabolism was still unclear. AIM OF THE STUDY: This study aimed to investigate the regulatory effect of MFP on lipid metabolism in mice with acute alcoholic liver injury, and to enrich the application of its hepatoprotective effect. MATERIALS AND METHODS: Fifty Specific Pathogen Free (SPF) Kunming (KM) male mice were divided into five groups randomly, including normal control group, model group, bifendate positive group (220 mg/ kg), MFPA1 group (50 mg/ kg) and MFPB1 group (50 mg/ kg). A model of acute alcoholic liver injury was established by treating the mice with ethanol. The liver sections were processed and histopathological changes was observed with hematoxylin and eosin staining. The secretion levels of biochemical indexes in the liver and serum were assayed by ELISA. The untargeted lipidomics analysis was performed on a Q Exactive Focus quadrupole orbitrap high resolution mass spectrometry coupled with a Dionex Ultimate 3000 RSLC (HPG) ultra-performance liquid chromatography (UPLC-Q-Orbitrap-HRMS) system (Thermo Fisher Scientific), with a HESI ionization source. RESULTS: It was observed that abnormal glutamic-pyruvic transaminase enzyme (ALT), glutamic-oxaloacetic aminotransferase (AST), triglyceride (TG), superoxide dismutase (SOD), and malondialdehyde (MDA) concentrations were ameliorated after irrigation of MFP or bifendate. Histopathology examination showed that intragastric infusion of MFP can be helpful in the repair of damaged liver in mice. The multivariate analysis of hepatic lipids showed segregation of ethanol-fed groups from the normal controls. After the comparison of mass spectra, 10 lipids were found to have different content in the normal control group and the model group. Differential lipids that were increased by ethanol exposure included fatty acids, phosphatidylcholine, and lyso-phosphatidylethanolamine, whereas lyso-phosphatidylcholine decreased. Among them, 4 lipids almost returned to the level of normal mice after MFP treatment. CONCLUSION: The therapeutic effect of MFP on acute alcoholic liver injury may be achieved by regulating a variety of metabolic pathways, including linoleic acid metabolism, α - linolenic acid metabolism, and glycerolphospholipid metabolism. These results revealed that MFP efficiently exerted hepatoprotective benefits, and its potential effect was associated with the amelioration of lipid metabolism.

Objective Findings on the K-Doped g-C3N4 Photocatalysts: The Presence and Influence of Organic Byproducts on K-Doped g-C3N4 Photocatalysis.

The thermal-condensation method is widely used for the synthesis of K-doped g-C3N4 photocatalysts, but the presence of organic byproducts in the resultant products is often overlooked in previous reports. Here, we demonstrated the universal presence of organic byproducts in K-doped g-C3N4 synthesized by typical thermal condensation of KOH/melamine, KOH/dicyandiamide, or KOH/urea. Taking the K-doped g-C3N4 photocatalysis for the degradation of dimethyl phthalate as an example, the negative influence of the organic byproducts on K-doped g-C3N4 photocatalysis was confirmed. Specifically, the organic byproducts can be gradually dissolved into the photocatalytic system of K-doped g-C3N4 as new and stable pollutants. Based on the solubility investigations on the byproducts in several solvents, hot-water washing was demonstrated to be a relatively effective approach to remove the organic byproducts from K-doped g-C3N4. The formation of organic byproducts during the synthesis of K-doped g-C3N4 could be ascribed to the fact that the presence of K salts in melamine, dicyandiamide, or urea molecules results in their insufficient thermal condensation into expected g-C3N4. The present work provides objective information about the K-doped g-C3N4 photocatalysts and reminds researchers about the influence of the organic byproducts on the applications of the other impurity-doped g-C3N4 photocatalysts.

Chemically modified mesoporous wood: a versatile sensor for visual colorimetric detection of trinitrotoluene in water, air, and soil by smartphone camera.

There is great interest in detection of the level of 2,4,6-trinitrotoluene (TNT) explosive due to its importance in public security and environmental protection fields. The conventional chemical sensors do not simultaneously realize simple, rapid, sensitive, selective, and direct detection of TNT in different medium without sample pretreatment. Here we present a modified wood-based chemical sensor for visual colorimetric detection of TNT in water, air, and soil. The natural wood undergoes a delignified process, which is further functionalized by 3-aminopropyltriethoxysilane (APTES). When TNT solutions are introduced, the wood-based sensor shows a colorimetric transition from light yellow to brown for naked-eye readout because of the generation of Meisenheimer complex between APTES and TNT. The photographs are collected by smartphone camera, and the RGB components are extracted to calculate the adjusted intensity for qualitative detection of TNT. This visual colorimetric sensor for TNT solution displays a linearity in the range of 0.01-5 mM with a limit of detection of 3 µM. In addition, by taking advantage of its inherent mesostructure, the wood-based sensor can be employed for visual detection of TNT vapor as well. Furthermore, it is also able to directly detect TNT in wet soil samples based on capillary action, in which TNT carried by water transports upward along the wood microchannel, triggering the generation of Meisenheimer complex. Graphical Abstract.

Capric Acid Hybridizing Fly Ash and Carbon Nanotubes as a Novel Shape-Stabilized Phase Change Material for Thermal Energy Storage.

Capric acid (CA) is one of the most promising phase change materials to be used in reducing the energy consumption of buildings due to its suitable phase change temperature and high latent heat. In this paper, a novel shape-stabilized phase change material (SSPCM) is fabricated by "hazardous waste" fly ash (FA) via simple impregnation method along with CA and carbon nanotubes (CNTs). In this composite, raw FA without any modification serves as the carrier matrix to improve structural strength and overcome the drawback of the leakage of liquid CA. Simultaneously, CNTs act as an additive to increase the thermal conductivity of composites. The results of leakage tests indicate that CA was successfully confined as 20 wt % in the composite. Then, various characterization techniques were adopted to investigate the structure and properties of the prepared SSPCM of CA/FA/CNT. Scanning electron microscopy and Fourier transform infrared spectroscopy results showed that CA was well adsorbed into the microstructure of FA, and there was no chemical interaction between the components of the composites. Thermogravimetric analysis results demonstrated that the SSPCM presented good thermal stability. Differential scanning calorimetry results indicated that the melting temperature and freezing temperature of CA/FA/CNT were 31.08 and 27.88 °C, respectively, and the latent heats of CA/FA/CNT during the melting and freezing processes were 20.54 and 20.19 J g-1, respectively. Moreover, compared to the CA and CA/FA, the heat transfer efficiency of CA/FA/CNT was significantly improved by doping 1, 3, 5, and 7 wt % of CNT. All of the results suggest that CA/FA/CNT possessed comfortable melting and freezing temperatures, excellent thermal stability, high latent heat value, and favorable thermal conductivity, and therefore, it is a suitable thermal storage material for building applications. Simultaneously, CA/FA/CNT can improve the comprehensive utilization level of FA.