科研成果

Confined fluids undergo substantial changes in terms of their physicochemical properties when the pore radius reduces to the nanometric scale and be comparable to the molecular size. Adsorptions, which are the corresponding changes in the concentration of a given fluid at the interface compared with the other contacting phase, strongly affect the vapour-liquid equilibrium (VLE), especially in nanopores. No published literature so far has been found to study the critical shifts of confined fluids with adsorptions in nanopores. In this study, first, the van der Waals (vdW) and Soave-Redlich-Kwong (SRK) equations of state (EOSs) are extended to calculate the VLE of confined fluids in nanopores. Second, a new empirical correlation is developed to calculate the fluid adsorption thickness in nanopores. Finally, two generalized analytical formulations, on a basis of the modified vdW and SRK EOSs, are initially proposed to calculate the shifts of critical temperatures and pressures by considering the fluid adsorptions in nanopores. All the extended EOSs, new adsorption correlation, and two generalized formulations have been validated to be accurate by comparing with the experimental or literature data. Overall, the critical properties of the confined fluids are found to shift more with adsorptions in nanopores. Moreover, the compressibility factors of the confined Lennard–Jones fluids are proven to be universal and independent of the pore radius effect.

To reduce the burden of storing and transmitting audio signals, they are often compressed with a lossy single-channel code. Because the high-frequency components are effectively truncated when using a low bitrate encoder, listeners may experience the sound as being uncomfortable, muffled, or dull. To compensate for the perceived degradation, bandwidth extension technology can be used to regenerate the missing high frequencies from the low-frequency components during the decoding process. In this paper the authors propose a bandwidth extension method based on Generative Adversarial Networks (GAN), which is used to estimate the relationship between the MDCT spectrum in the high-frequency part and the low-frequency part. It is evaluated by a discriminant network in the GAN to get a more natural result. A complete audio coding system was built by using AAC Low Complex as the single-channel core encoder with the proposed bandwidth extension method. To evaluate the audio quality decoded by the new system, a subjective evaluation experiment was carried out using the HE-AAC as the baseline system with the MUSHRA experimental method.

    While short-chain chlorinated paraffins (SCCPs) comprise a myriad of components whose physicochemical properties are extremely diverse, many previous studies characterized the SCCP mixtures collectively using a single set of physicochemical properties when modeling the global environmental fate and risk. In this work, we explore whether a discrepancy exists between simulations based on a single set of physicochemical properties and multiple component-specific ones in global fate and risk modeling, and the environmental condition (e.g., proximity to emission source vs. temperature) in which such a discrepancy is most notable. We simulated the environmental concentrations and compartmental distribution of SCCPs, using a mechanistic fugacity-based multimedia BETR-Global model. We observed a discrepancy between modeled concentrations based on a single and multiple sets of properties, which is more notable in regions with a low temperature and negligible emissions, e.g., the remote and cold background Arctic region. The modeled compartmental distribution differs slightly between simulations based on different sets of physicochemical properties. While using a single set of properties minimizes input data required for model-based evaluation of the risk of SCCPs, it tends to underestimate the environmental occurrence and risk in remote and cold regions, which are vulnerable and hence deserve a more conservative evaluation conclusion, and prevents us from drawing conclusions on which SCCP component is of greatest concern. The current work can be a relevant step towards improving the methodology for global environmental modeling and risk assessment of SCCPs and other complex halogenated chemical mixtures.

Graphene modified anatase/titanate nanosheets (G/A/TNS) synthesized through hydrothermal treatment were used for solar-light-driven photocatalytic degradation of a typical pharmaceutically active compound, sulfamethazine (SMT). The optimal material was synthesized with 0.5 wt% of graphene loading (G/A/TNS-0.5), which could efficiently degrade 96.1% of SMT at 4 h. G/A/TNS-0.5 showed enhanced photocatalytic activity compared with the neat anatase and unmodified anatase/titanate nanosheets (A/TNS). UV–vis diffuse reflection spectra indicated that G/A/TNS-0.5 had a lower energy band gap (Eg) of 2.8 eV than A/TNS (3.1 eV). The grafted graphene acted as an electron transfer mediator after photoexcitation, resulting in inhibition on rapid recombination of electron-hole pairs. More importantly, architecture of graphene and titanate nanosheets both with two-dimensional structures greatly facilitated the photoexcited electron transfer. •OH and 1O2 were the primary reactive oxygen species (ROS) to SMT degradation. Fukui index (f -) derived from density functional theory (DFT) calculation predicted the active sites on SMT molecule, and then SMT degradation pathway was proposed by means of intermediates identification and theoretical calculation. Furthermore, G/A/TNS-0.5 could be well reused and 90.5% of SMT was also degraded after five runs. The developed new photocatalysts show great potential for degradation of emerging organic contaminants through photocatalysis under solar light.

BACKGROUND: A growing amount of data suggests that n-3 (ω-3) polyunsaturated fatty acid (PUFA) intake may modify the genetic association with weight change. OBJECTIVES: We aimed to prospectively test interactions of habitual consumption of n-3 PUFAs or fish, the major food source, with overall genetic susceptibility on long-term weight change. DESIGN: Gene-diet interactions were examined in 11,330 women from the Nurses' Health Study (NHS), 6773 men from the Health Professionals Follow-Up Study (HPFS), and 6254 women from the Women's Health Initiative (WHI). RESULTS: In the NHS and HPFS cohorts, food-sourced long-chain n-3 PUFA intake showed directionally consistent interactions with genetic risk score on long-term changes in BMI (P-interaction = 0.01 in the HPFS, 0.15 in the NHS, and 0.01 in both cohorts combined). Such interactions were successfully replicated in the WHI, an independent cohort (P-interaction = 0.02 in the WHI and 0.01 in the combined 3 cohorts). The genetic associations with changes in BMI (in kg/m2) consistently decreased (0.15, 0.10, 0.07, and -0.14 per 10 BMI-increasing alleles) across the quartiles of long-chain n-3 PUFAs in the combined cohorts. In addition, high fish intake also attenuated the genetic associations with long-term changes in BMI in the HPFS (P-interaction = 0.01), NHS (P-interaction = 0.03), WHI (P-interaction = 0.10), and the combined cohorts (P-interaction = 0.01); and the differences in BMI changes per 10 BMI-increasing alleles were 0.16, 0.06, -0.08, and -0.18, respectively, across the categories (≤1, 1∼4, 4∼6, and ≥7 servings/wk) of total fish intake. Similar interactions on body weight were observed for fish intake (P-interaction = 0.003) and long-chain n-3 PUFA intake (P-interaction = 0.12). CONCLUSION: Our study provides replicable evidence to show that high intakes of fish and long-chain n-3 PUFAs are associated with an attenuation of the genetic association with long-term weight gain based on results from 3 prospective cohorts of Caucasians.