Developing a new strategy to retain phosphoric acid (PA) to improve the performance and durability of high‐temperature proton exchange membrane fuel cell (HT‐PEMFC) remains a challenge. Here, a ...strategy for ion‐restricted catcher microstructure that incorporates PA‐doped multi‐quaternized poly(fluorene alkylene‐co‐biphenyl alkylene) (PFBA) bearing confined nanochannels is reported. Dynamic analysis reveals strong interaction between side chains and PA molecules, confirming that the microstructure can improve PA retention. The PFBA linked with triquaternary ammonium side chain (PFBA‐tQA) shows the highest PA retention rate of 95%. Its H2/O2 fuel cell operates within 0.6% voltage decay at 160 °C/0% RH, and it also runs over 100 h at 100 °C/49% RH under external humidification. This combination of high PA retention, and chemical and dimensional stability fills a gap in the HT‐PEMFC field, which requires strict moisture control at 90–120 °C to prevent acid leaching, simplifying the start‐up procedure of HT‐PEMFC without preheating.
With the cooperation of ion pair interaction for multi‐quaternized side chains with phosphoric acid (PA) and microstructure with nanochannels, the PFBA‐tQA tends to form ion‐restricted catcher microstructure, which efficiently improves PA retention under an external humidity environment. It can utilize water to promote ion conduction without PA loss and possesses grant advantages for fuel cells when worked under medium and high‐temperature regions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
As promising cathode for sodium‐ion batteries, Na+ Superionic Conductor (NASICON)‐type materials have attracted attention owing to their excellent structural stability, superior ionic conductivity, ...and small volume expansion. However, the vanadium‐based NASICON‐type cathode with the biotoxicity and exorbitant price of V element and the iron‐based cathode with low mean working voltage as well as the intrinsic poor electronic conductivity of polyanionic compounds hinder their practical applications. Herein, a double‐carbon‐layer decorated heterogeneous composite, Na3V2(PO4)3‐Na3Fe2(PO4)(P2O7) (NVFPP/C/G), is successfully prepared for addressing these limitations. Due to their synergistic effect, NVFPP/C/G exhibits excellent electrochemical performance in half‐cell system and superior full‐cell performance when matched with hard carbon anode. Furthermore, the phase composition, electrode kinetics, and phase transition are confirmed by combined analyses of slow scanning power X‐ray diffraction, high‐resolution transmission electron microscopy, cyclic voltammetry with various scan rates, galvanostatic intermittent titration technique, ex situ X‐ray photoelectron spectra, and in situ X‐ray diffraction. This study portends a promising strategy to utilize composite structure engineering for developing advanced polyanionic cathodes.
A double‐carbon‐layer decorated heterogeneous Na3V2(PO4)3‐Na3Fe2(PO4)(P2O7) composite is proposed as cathode for sodium‐ion batteries. Due to the synergistic effect, it exhibits excellent electrochemical performance in half‐cell system and superior full‐cell performance. The heterogeneous composite structure engineering strategy provides a new approach to design high‐performance polyanionic cathodes for batteries.
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Forest age is a crucial parameter for evaluating the state and potential of carbon sequestration in forest ecosystems. However, the lack of a time-series forest age will lead to an inability to ...capture forest disturbance and restoration history, resulting in increased uncertainty in estimating forest carbon sinks. To address this issue, we aimed to propose an integrated algorithm of forest age estimation based on forest disturbance and recovery history, using Zhejiang Province forests as an example. Based on the Google Earth Engine (GEE) platform, we first used random forest (RF) to estimate the forest age in 2004, and then integrated the LandTrendr algorithm with RF to detect the forest loss and gain year during 2005-2019, and finally derived and mapped the time-series forest age distribution from 2004 to 2019. The results show that: 1) the <inline-formula> <tex-math notation="LaTeX">{R}^{2} </tex-math></inline-formula> (<inline-formula> <tex-math notation="LaTeX">{\ge }0.6 </tex-math></inline-formula>) and the RMSE (<inline-formula> <tex-math notation="LaTeX">{\le }5 </tex-math></inline-formula> years) revealed that the constructed RF models could estimate forest age with high reliability; 2) the integrated algorithm of LandTrendr and RF effectively extracted the forest disturbance and recovery regions with overall accuracies (OAs) above 0.7, while the extracted forest area in Zhejiang Province has a net increase of 2206.86 km2 during 2005-2019; and 3) the forest age from 2004 to 2019 was still dominated by young- and middle-aged forests, with a shift in age dominance from 20-30 to 30-40 years old after 2013. This study provided an effective methodological idea for time-series forest age estimation and reliable basic data for estimating past and future forest carbon sinks.
To prepare an effective immune preparation to treat hepatitis B, hens were immunized with hepatitis B vaccines, and then anti-HBV egg yolk extraction （anti-HBV EYE） was refined from egg yolk by a ...dialyzable method. Its chemical characteristics were identified by ultraviolet spectrum, HPLC, Lowry analysis and pharmacopocia-raleted methods. The specific immunological activity was examined by leukocyte adherence inhibition （LAI） in vitro and delayed type hypersensitivity （DTH） in vivo. Anti-HBV EYE was a small dialyzable substance with molecular weight less than 12 kD containing 18 kinds of amino acids. The preparation could obviously inhibit LAI and DTH which was similar to hepatitis B virus-specific transfer factor of pig spleen. However, there were no similar effects observed in the nonspecific transfer factor （NTF） group, control egg yolk extraction （CEYE） group and hepatitis A virus （HAV） group. The results suggested that anti-HBV EYE contained hepatitis B virus-specific transfer factor （STF） and had the antigen-specific cell immune activity similar to PSHBV-TF. The STF obtained from egg yolk of the hens immunized with specific antigen, might be a potential candidate for immunoregulation in hepatitis B prevention and treatment.
B cells play an important role in the clearance of hepatitis B virus （HBV） and protection against reinfection. However, the functional characteristics of these cells that are associated with the ...outcome of chronic HBV infection remain unknown. We comprehensively investigated the frequency, phenotype, and function of peripheral B-cell subsets from CHB patients in different phases： immune tolerance （IT）, immune activation （IA）, immune clearance （IC）, responders with HBsAg seroconversion （resolved patients, RP）, and healthy controls （HC）. IA patients displayed lower percentages of peripheral blood memory B cells compared with the other groups. Overall polyclonal activation of B cells, indicated by higher levels of activation markers and secretion of IgG and IgM, was observed in IA patients. This B-cell hyperactivation could be induced by increased IFN-a and soluble CD40 ligands in IA patients. Notably, the expression of the co-stimulator molecule CD80 and serum HBsAb and the frequency of HBsAg-specific B cells were significantly decreased in IT, IA, and IC patients compared with HC subjects. More importantly, the B-cell hyperactivation, co-stimulatory molecule downregulation and HBsAg-specific B-cell impairment were reversed in RP patients. The reversal of B-cell hyperactivation and functional impairment is associated with HBsAg seroconversion in chronic hepatitis B patients.
The aim of this study was to evaluate the efficacy of mosaicplasty with tissue-engineered cartilage for the treatment of osteochondral defects in a pig model with advanced MR technique. Eight ...adolescent miniature pigs were used. The right knee underwent mosaicplasty with tissue-engineered cartilage for treatment of focal osteochondral defects, while the left knee was repaired via single mosaicplasty as controls. At 6, 12, 18 and 26 weeks after surgery, repair tissue was evaluated by magnetic resonance imaging （MRI） with the cartilage repair tissue （MOCART） scoring system and T2 mapping. Then, the results of MRI for 26 weeks were compared with findings of macroscopic and histologic studies. The MOCART scores showed that the repaired tissue of the tissue-engineered cartilage group was statistically better than that of controls （P 〈 0.001）. A significant correlation was found between macroscopic and MOCART scores （P 〈 0.001）. Comparable mean T2 values were found between adjacent cartilage and repair tissue in the experimental group （P 〉 0.05）. For zonal T2 value evaluation, there were no significant zonal T2 differences for repair tissue in controls （P 〉 0.05）. For the experimental group, zonal T2 variation was found in repair tissue （P 〈 0.05）. MRI, macroscopy and histology showed better repair results and bony incorporation in mosaicplasty with the tissue-engi- neered cartilage group than those of the single mosaicplasty group. Mosaicplasty with the tissue-engineered cartilage is a promising approach to repair osteochodndral defects. Morphological MRI and T2 mapping provide a non-invasive method for monitoring the maturation and integration of cartilage repair tissue in vivo.
Nest-like and multilayered-disk-like Bi2WO6 photocatalysts were synthesized through a hydrothermal strategy using thiourea and acetic acid as complexing agents. The nest-like Bi2WO6 showed excellent ...visible-light-driven photocatalytic performance, and it could decompose rhodamine B（RhB） within 100 minutes. This excellent performance resulted from its special microstructure and the relatively large surface area.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
9.
Study on fresh keeping techniques of separate flower by irradiation Zou Weimin; Zheng Shihuo; Li Xuejun (Guangdong Provincial Academy of Agricultural Sciences, Guangzhou (China). Inst. of Biotechnology)
Journal of Nuclear-Agricultural Sciences (China),
(Mar 1993), Volume:
14, Issue:
2
Journal Article
Mutagenic effects of C02 laser on broad bean Zou Weimin; Cao Jing (Guangdong Provincial Academy of Agricultural Sciences, Guangzhou (China). Inst. of Botany); Wu Yuyun
Guangdong Agricultural Sciences (China),
(Feb 1992)
1
Publication
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