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(1) Background--The rapid development of forest ecotourism has also brought environmental pollution and ecological damage. In order to better respond to the "Two Mountains" theory and implement the ecological civilization construction strategy, and promote the sustainable development of forest ecotourism industry, it is crucial to clarify and guide tourists' green purchasing behavior. Studying the formation mechanism of tourists' green purchase intention is helpful to the sustainable development of forest ecotourism. (2) Methods--The research hypotheses were proposed based on the theory of planned behavior (TPB), value-belief-norm theory (VBN) and their integrated framework. The research data came from the questionnaire survey of the tourists in Wuyishan National Park in Fujian Province in October 2023, and a total of 407 valid questionnaires were obtained. Then, a structural equation model was constructed to analyze the formation mechanism of tourists' green purchase intention. (3) Results--First, the theoretical model of the formation mechanism of green purchase intention constructed in this paper has strong explanatory power and predictive power for tourists' green purchase intention. The integration framework of TPB and VBN is effective in explaining and predicting the influencing factors and formation mechanism of tourists' green purchase intention. Second, in the hypothetical path designed according to TPB, the research results show that the green purchasing behavior attitude and subjective norms have a positive impact on tourists' green purchase intention, while the perceived behavior control has no significant impact on tourists' green purchase intention. In the hypothetical path designed according to the VBN theory, the research results show that altruism values have a significant positive impact on the awareness of consequence, the awareness of consequence has a significant positive impact on the attribution of responsibility, the attribution of responsibility has a significant positive impact on the moral norms, and the moral norms has a positive impact on the tourists' green purchase intention. This indicates that the formation of tourists' green purchase intention is influenced by the chain causal mechanism of the VBN theory. In the hypothetical path designed according to the TPB-VBN integrated framework, the research results show that the awareness of consequence has a positive impact on the perceived behavior control and green purchasing behavior attitude, and the subjective norms have a positive impact on the moral norms, which indicates that the interaction of TPB and VBN theory can further explain the formation mechanism of tourists' green purchase intention. Third, there is no significant difference in the green purchase intention of the tourists of different genders and ages, but there is a significant difference between the tourists with different education levels, and with the increase of education level, the green purchase in tention of the tourists increases significantly. (4) Conclusions and Discussions--In order to improve tourists' green purchase intention, the following policy suggestions are put forward: First, strengthen publicity and education, enrich publicity content and broaden publicity channels, so as to enhance tourists' ecological awareness and moral responsibility in purchasing green tourism products and services, and enhance their altruistic values. Second, improve the tourism market, explore the green, low-carbon and high-quality development of forest ecotourism, and enhance the green purchasing power of tourists. Enrich the product and service categories and improve the availability of green tourism products and services. Enterprises are encouraged to design and produce green tourism products to convey the concept of sustainable development of forest ecotourism. Third, create a good social atmosphere to form a collective and social green purchasing power, and enhance the sense of responsibility and model of tourists. Use a variety of means comprehensively to strengthen the social norms on the tourists' individual behavior constraints and guidance. Shape the collective and social forces of green purchasing behavior through publicity and education, institutional norms and public welfare activities. [ABSTRACT FROM AUTHOR]

• A combination strategy based on molecular design and post-synthetic modification was proposed to prepare conductive COF coating. • The prepared COF coating possess high polarity, excellent electrochemical performance and good durability. • EE-SPME technology based on the prepared COF coating can efficiently and quickly extract polar BPs. • A sensitive EE-SPME-GC–MS/MS method was developed for the detection of trace BPs in tea samples. Design and preparation of fiber coatings with excellent electrochemical performance and high polarity is significant for efficient extraction of polar targets in electro-enhanced solid-phase microextraction (EE-SPME). In this work, a combination strategy for structure regulation of covalent organic framework (COF) was proposed to fabricate a nitrogen-rich thiocarbamide linked COF coating (Thiocarbamide-TZ-DHTP) via molecular design and post-synthetic thiocarbamide conversion. The prepared COF coating possesses a large number of O, N, and S functional groups, which not only endow the coating with higher polarity but also significantly enhance its electrochemical performance. The COF coating was used for EE-SPME of polar bisphenols (BPs), demonstrating excellent enrichment efficiency and durability. Subsequently, coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS), a sensitive method was developed for determination of trace BPs. The established method possess wide linear ranges (2.0–800.0 ng L−1), good correlation coefficients (0.9985–0.9994) and low detection limits (0.1–2.0 ng L−1). Moreover, the established method had been successfully applied to detection of trace BPs in tea beverage with satisfactory recoveries (81.6 % to 118.6 %). This research provides a feasible pathway for preparing COF coating with excellent electrochemical performance and high polarity for EE-SPME. [ABSTRACT FROM AUTHOR]

Developing facile and general functionalization strategies to improve the durability of covalent organic framework (COF) coatings and their affinity for polar targets is of great significance for solid-phase microextraction (SPME) technology. In this work, a facile and general amidation strategy was developed for conversion from reversible (imine) to irreversible (amide) linkages in COF coatings. After the amidation, the durability of the obtained amide-linked covalent organic framework (Am-P-COF) coating was greatly improved, and the adsorption efficiency for polar aromatic amines (AAs) was also significantly increased. Moreover, this strategy is also applicable to the amidation of other two COF coatings, showing good general applicability. The obtained Am-P-COF coated fiber was used for SPME, and then coupled with gas chromatography tandem mass spectrometry (GC-MS/MS) to detect AAs. Under the optimal SPME conditions (extraction temperature: 50 °C, extraction time: 30 min, stirring rate: 600 rpm, pH: 8, NaCl concentration: 5.0 mg mL−1, desorption temperature: 290 °C and desorption time: 10 min), a detection method for trace AAs was established. The established method possess wide linear ranges (0.5–500.0 ng L−1), good correlation coefficients (0.9986–0.9993) and low detection limits (0.1–0.5 ng L−1). Moreover, the established method had also been successfully applied to detection of trace AAs in bottled tea beverage and plastic bags packed tea with satisfactory recoveries (83.5 %–116.8 %). This research provides a facile and general pathway for increasing the durability of COF coatings and affinity to the polar AAs. The detection method based on the obtained fibers possesses high sensitivity, satisfactory reproducibility and good precision. [Display omitted] • An amidation strategy of linkages in COF was developed for the functionalization of COF coatings. • The amidation strategy possess good general applicability for other different COF coating. • The amidation improves the durability of the COF coating and the absorption efficiency for polar AAs. • A sensitive SPME-GC-MS/MS method was developed for the detection of trace AAs in the beverages. [ABSTRACT FROM AUTHOR]

Rapid and convenient preparation of covalent organic framework (COF) coated fibers is of great significance to solid-phase microextraction (SPME) technology. In this work, a novel chemical preparation strategy was established for rapid fabrication of β -ketoenamine-linked COF coatings, in which clay-like starting materials of COFs were first wrapped on the fiber surface through self-viscosity and further fixed on the fiber in an oven via chemical bonding. Based on this strategy, four different COF (TpTph, TpPa-1, TpBD and TpTpb) coated fibers was fabricated within 1 h, which is very rapid compared to the recently reported research. Moreover, the strategy also demonstrates the good general applicability for COF fiber preparation. Subsequently, the TpTph coated fiber was used to develop a new SPME method for gas chromatography-tandem mass spectrometry (GC-MS/MS) of trace phthalic acid esters (PAEs) in environmental water. The developed analytical method compared to the previous SPME methods for PAEs based on other sorbents possesses low limits of detection (LODs, 0.02–0.08 ng L−1), and better or comparable precision (RSD ≤9.4%, n = 6), and relatively short extraction time. Furthermore, the trace PAEs (0.27–11.62 ng L−1) in the real water samples were successfully detected with recoveries of 82.2–117.5%. The above results indicates that the proposed fiber preparation strategy is reliable and opens a potential avenue for rapid and facile fabrication of COF coated fibers. [Display omitted] • A general strategy was developed for rapidly covalent immobilization of COF coatings. • The prepared fibers possess good extraction performance, excellent stabilities and working life. • The proposed SPME-GC-MS/MS method exhibited low detection limits for PAEs. [ABSTRACT FROM AUTHOR]

A facile and rapid strategy for preparation of covalent organic framework (COF) coated fibers at ambient temperature is urgently needed for solid-phase microextraction (SPME) technology. In this work, an in situ room-temperature rapid growth strategy was developed to high-efficiently fabricate imine-linked COF (TPB-DVA) coated fibers in as little as 30 min at room temperature, and the thickness of the coating reached 9 μm. The prepared TPB-DVA coated fiber offer high thermal and chemical stability, and outstanding service lifetime. Moreover, we generalize this strategy to other two imine-linked COF (TPB-DMTP and TFPB-TAPB) coated fibers and the fibers were fabricated at room temperature for 3 h and 12 h, respectively, which demonstrate the applicability of this strategy. Subsequently, a SPME-GC-MS/MS analytical method was developed for trace pyrethroids (PYs) detection, which exhibited high enhancement factors (EFs, 2700–13195), wide linear range (0.08–800 ng L−1), low limits of detection (LODs, 0.02–0.20 ng L−1), and good repeatability (RSD ≤ 8.5%, n = 6). Furthermore, the developed analytical method was applied to tea samples and trace PYs (1.31–4.32 ng L−1) were found with satisfactory recovery (80.2–119.8%). The above results demonstrated that the feasibility of the developed strategy for the facile and rapid fabrication of imine-linked COF coated fibers. [Display omitted] • The TPB-DVA coated fiber was fabricated within 30 min at room temperature by rapid in situ strategy. • This strategy demonstrate the general applicability for rapid fabrication of imine-linked COF coated fibers. • The developed SPME-GC-MS/MS analysis method for PYs in tea exhibited high sensitivity and low LOD. [ABSTRACT FROM AUTHOR]

Plant growth-promoting microbes (PGPMs) are documented to stimulate nitrification rates and reduce N 2 O emissions in acidic soils. These microbes play a role in the nitrogen (N) transformation process, although the specific functions and mechanisms by which they affect the gross N transformation are not well understood. In particular, the influence of PGPMs on the relative predominance of ammonia oxidizers in the nitrification process is still unclear. In this study, we conducted a 15N tracing experiment to reveal the impact of PGPM Bacillus velezensis SQR9 on gross N transformations in acidic soils, as well as the microbial pathways involved. SQR9 inoculation considerably enhanced the processes of soil gross mineralization and nitrification by 14.6 % and 29.5 %, respectively. This improvement was found to be associated with the soil's dissolved organic carbon (DOC) content and carbon-to‑nitrogen (C/N) ratio. SQR9 increased the abundance of ammonia-oxidizing bacteria (AOB), resulting in a substantial promotion of autotrophic nitrification, which occupied a dominant role (71.3–82.6 %) in the nitrification process. SQR9 significantly stimulated the proportion of AOB, indicating a transition from ammonia-oxidizing archaea (AOA) to AOB as the dominant ammonia oxidizers, hence promoting the gross nitrification rate. In conclusion, the heightened rates of N transformation are highly associated with the modification of the ammonia-oxidizer B. velezensis SQR9. Our findings offer an updated insight into how PGPMs cause N transformation and provide a theoretical basis for the sensible application of PGPMs in agricultural development. • SQR9 increases gross nitrification and mineralization rates in acidic soils. • SQR9 stimulates soil DOC and suppresses the C/N ratio to promote N transformation. • Autotrophic nitrification plays a dominant role in the nitrification process. • SQR9 increases the AOB contribution to nitrification to promote gross N transformation. [ABSTRACT FROM AUTHOR]

In this study, all‐optical organic–inorganic hybrid waveguide switches are proposed based on the photothermal effect of Au‐MOF composites. The embedded waveguide structure is directly defined using SiO2 grooves on a silicon substrate. Self‐synthesized Au‐MOF/PMMA and SiO2‐TiO2 network grafting PMMA are used as the core and cladding materials, respectively. The organic–inorganic hybrid shielding layer is formed using an oxygen ion etching process to avoid corrosion from the cladding solvent. A directional coupling switching structure is designed and fabricated. The switching time of the all‐optical device is 500 µs, the photothermal tuning sensitivity is 19.10 nm mW−1, the driving optical power consumption is 0.67 mW, and the extinction ratio is close to 9.83 dB. This technique is desirable for photothermal control of light in an all‐optical signal‐processing network. [ABSTRACT FROM AUTHOR]

The objective of this paper is to numerically investigate the thermodynamic effect during bubble collapse near a rigid boundary. A compressible fluid model is introduced to accurately capture the transient process of bubble shapes and temperature, as well as corresponding pressure, and velocity. The accuracy of the numerical model is verified by the experimental data of bubble shapes, and Keller-Kolodner equation as well as its thermodynamic equation. The results show that a bubble near the rigid boundary presents high-speed jet in collapse stage and counter jet in rebound stage, respectively. In the collapse stage, the bubble margin will shrink rapidly and do the positive work on the compressible vapor inside the bubble, then a significant amount of heat will be generated, and finally the generation of high-speed jet drives the low-temperature liquid outside the bubble to occupy the position of high-temperature vapor inside the bubble. In the rebound stage, the counter jet moving away from the rigid boundary takes part of heat away from the sub-bubble, which avoids the external work of the expansion of the sub-bubble and the temperature reduction caused by the dissipation effect of the vortex structure. In addition, the initial standoff has a significant effect on the thermodynamics of bubble oscillation. The temperature keeps increasing with the increase of the initial standoff in the collapse stage, while it shows a downward trend with the increase of the initial standoff in the rebound stage. That's because the high-speed jet and counter jet of bubble gradually disappear when the initial standoff increases, which is the important reason for the opposite evolution trend of temperature in collapse and rebound stage. [ABSTRACT FROM AUTHOR]

The objective of this paper was to investigate acoustic pressure waves and the transient flow structure emitted from the single bubble near an elastic boundary based on the particle image velocimetry (PIV). A combination of an electric-spark bubble generator and PIV were used to measure the temporal bubble shapes, transient flow structure, as well as the mid-span deflection of an elastic boundary. Results are presented for three different initial positions near an elastic boundary, which were compared with results obtained using a rigid boundary. A formula relating velocity and pressure was proposed to calculate the acoustic pressure contours surrounding a bubble based on the velocity field of the transient flow structure obtained using PIV. The results show the bubbles near the elastic boundary presented a "mushroom" bubble and an inverted cone bubble. Based on the PIV-measured acoustic pressure contours, a significant pressure difference is found between the elastic boundary and the underside of the bubble, which contributed to the formation of the "mushroom" bubble and inverted cone bubble. Furthermore, the bubbles had opposite migration direction near rigid and elastic boundaries, respectively. In detail, the bubble was repelled away from the elastic boundary and the bubble was attracted by the rigid boundary. The resultant force made up of a Bjerknes force and buoyancy force dominated the migration direction of the bubble. [ABSTRACT FROM AUTHOR]

An efficient and stable fiber coating is of great importance for solid-phase microextraction (SPME). In this study, carboxylated mesoporous carbon hollow spheres (MCHS-COOH) were developed as an efficient SPME coating of polar aromatic amines (AAs) for the first time. The MCHS-COOH coating material with high specific surface area (1182.32 m2 g−1), large pore size (10.14 nm), and rich oxygen-containing groups was fabricated via a facile H2O2 post-treatment. The as-prepared MCHS-COOH-coated fiber exhibited fast adsorption rate and excellent extraction properties, mainly due to its π–π interactions, hollow structure, and abundant affinity sites (carboxyl groups). Subsequently, coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS), a sensitive method with low limits of detection (0.08–2.0 ng L−1), a wide linear range (0.3–500.0 ng L−1), and good repeatability (2.0–8.8%, n = 6) was developed for the analysis of AAs. The developed method was validated against three river water samples, with satisfactory relative recoveries being obtained. The above results demonstrated that the prepared MCHS-COOH-coated fiber exhibited good adsorption capacity, suggesting a promising application to monitor trace polar compounds in real environment. [ABSTRACT FROM AUTHOR]

Accurate quantitative analysis of small molecule metabolites in biological samples is of great significance. Hydroxypolycyclic aromatic hydrocarbons (OH-PAHs) are metabolic derivatives of emerging pollutants, reflecting exposure to polycyclic aromatic hydrocarbons (PAHs). Macromolecules such as proteins and enzymes in biological samples will interfere with the accurate quantification of OH-PAHs, making direct analysis impossible, requiring a series of complex treatments such as enzymatic hydrolysis. Therefore, the development of matrix-compatible fiber coatings that can exclude macromolecules is of great significance to improve the ability of solid-phase microextraction (SPME) technology to selectively quantify small molecules in complex matrices and achieve rapid and direct analysis. We have developed an innovative coating with a stable macromolecular barrier using electrospinning and flexible filament winding (FW) technologies. This coating, referred to as the hollow fibrous covalent organic framework@polyionic liquid (F–COF@polyILs), demonstrates outstanding conductivity and stability. It accelerates the adsorption equilibrium time (25 min) for polar OH-PAHs through electrically enhanced solid-phase microextraction (EE-SPME) technology. Compared to the powder form, F–COF@polyILs coating displays effective non-selective large-size molecular sieving. Combining gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS/MS), we have established a simple, efficient quantitative analysis method for OH-PAHs with a low detection limit (0.008–0.05 ng L−1), wide linear range (0.02–1000 ng L−1), and good repeatability (1.0%–7.3 %). Experimental results show that the coated fiber exhibits good resistance to matrix interference (2.5%–16.7 %) in complex biological matrices, and has been successfully used for OH-PAHs analysis in human urine and plasma. FW technology realizes the transformation of the traditional powder form of COF in SPME coating to a uniform non-powder coating, giving its ability to exclude large molecules in complex biological matrices. A method for quantitatively detecting OH-PAHs in real biological samples was also developed. Therefore, the filament winding preparation method for F–COF@polyILs coated fibers, along with fibrous COFs' morphology control, has substantial implications for efficiently extracting target compounds from complex matrices. [Display omitted] • a novel electrospun filament winding strategy was proposed to directly prepare non-powder covalent organic frameworks. • This strategy built a solid phase microextraction (SPME) fiber coating with mechanically stable macromolecular barriers. • This coating overcame matrix effects in complex samples and simplify sample handling. • A sensitive electro-enhanced-SPME-GC-MS/MS method was developed for the detection of trace monohydroxy polycyclic aromatic hydrocarbons in biological samples. [ABSTRACT FROM AUTHOR]

Pipette tip solid-phase extraction (PT-SPE) as a miniaturized solid-phase extraction technique have a wide range of applications in the field of sample pretreatment. In this study, ionic covalent organic frameworks@cotton (iCOF@cotton) were facilely synthesized by mechanochemical grinding method only in half an hour, and used as the adsorbents of PT-SPE. The synthesized iCOF@cotton not only had high specific surface area, suitable pore structure and cationic charge groups of iCOF that can extract polar targets quickly, but also reduced the problem of high back pressure of PT-SPE by the addition of cotton, thus accelerating extraction time. Combined with high performance liquid chromatographic tandem mass spectrometry (HPLC-MS/MS), an efficient and sensitive method was established for detection of domoic acid (DA, a toxin produced by algae). Under the optimal conditions, the proposed analysis method displayed excellent analytical performance, including broad range of linearity (10–1000 pg mL−1), low limit of detection (LOD, 5 pg mL−1), high correlation coefficient (0.9993), satisfactory precision (RSDs ≤6.4 %). In addition, the developed method was applied to the detection of DA in marine samples, and detected trace DA (18.6 pg mL−1) with satisfactory recovery (85.7%–107.2 %). The above results indicated that the prepared iCOF@cotton have great potential as the adsorbents for PT-SPE. [Display omitted] • Ionic covalent organic frameworks@cotton were fast and conveniently synthesized by mechanochemistry methods. • Ionic covalent organic frameworks have abundant cationic charge groups and high adsorption capacity for domoic acid. • The cotton effectively reduced high back pressure in the pipette tip solid-phase extraction. • The method was successfully applied to the enrichment of domoic acid in marine samples. [ABSTRACT FROM AUTHOR]

• A novel piperazine-linked CuPc-MCOF with outstanding conductivity was obtained. • The obtained CuPc-MCOF as fiber coating has high chemical and thermal stability. • CuPc-MCOF exhibited multiple synergistic effects with CPs in EE-SPME process. • The method was used for determination of CPs in seawater and seafood samples. Conductive covalent organic frameworks (COFs) have received considerable attention and are critical in various applications such as electro-enhanced solid-phase microextraction (EE-SPME). In this work, a novel piperazine-linked copper-doped phthalocyanine metal covalent organic framework (CuPc-MCOF) was synthesized with good stability and high electrical conductivity. The synthesized CuPc-MCOF was then used as an EE-SPME coating material for extraction of five trace chlorophenols (CPs), including 2,4-dichlorophenol (2,4-DCP), 2,6-dichlorophenol (2,6-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,4,5-trichlorophenol (2,4,5-TCP) and 2,4,5,6-tetrachlorophenol (2,4,5,6-TCP), exhibiting excellent extraction performance because of various synergistic forces between CuPc-MCOF fibers and CPs. By combining EE-SPME with gas chromatography-tandem mass spectrometry (GC–MS/MS), a sensitive method for CPs detection was established with a low limit of detection (0.8–5 ng L−1) and good reproducibility (RSD≤8.4%, n = 3). This method was then successfully applied to the analysis of trace CPs in real samples of seawater and seafood. Results showed that the developed CuPc-MCOF coating material possessed superior extraction performance and potential application in extraction of trace polar pollutants from complex samples. [ABSTRACT FROM AUTHOR]