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| 1 | DFT study of difference caused by catalyst supports in Pt and Pd catalysis of oxygen reduction reaction显示文摘Based on an experimental phenomenon that catalytic activity of Pt and Pd for oxygen reduction reaction (ORR) changes with catalyst supports from C to TiO2, density function theory (DFT) was used to elucidate the cause behind the difference in catalysis caused by catalyst supports. First, factors closely associated with the first electron transfer of the ORR were assessed in the light of quantum chemistry. Then intermediate (atomic oxygen, O) adsorption strength on the catalyst surface was calculated. The results show that, in terms of minimum energy difference, the best orbital symmetry match, and the maximum orbital overlap, TiO2 does bring about a very positive effect on catalysts Pd/TiO2 for the first electron transfer of the ORR. Especially, TiO2 remarkably expands the space size of Pd/TiO2 HOMO orbital and improves orbital overlap of Pd/TiO2 HOMO and O2 LUMO. The analysis of deformation density and partial density of state shows that the strong interaction between Pt and Ti leads to a strong adsorption of intermediate O on Pt/TiO2, but the strong interaction between Pd and surface O causes positive net charge of Pd and a weak adsorption of intermediate O on Pd/TiO2. Thus, the ORR can proceed more smoothly on Pd/TiO2 than Pt/TiO2 in every respect of maximum orbital overlap and rate delay by intermediate O. The research also discloses that several factors lead to less activity of TiO2-supported Pt and Pd catalysts than the C-supported ones for the ORR. These factors include the poor dispersion of Pt and Pd particles on TiO2, poor electric conduction of TiO2 carrier itself, and bigger energy difference between HOMO of TiO2-carried metallic catalysts and LUMO of O2 molecule due to electrons deeply embedded in the semiconductor TiO2 carrier. | LI Li WEI ZiDong ZHANG Yi QI XueQiang XIA MeiRong ZHANG Jie SHAO ZhiGang SUN CaiXin | 2009 | Science China Chemistry2009，52，5： | 6 |
| 2 | Channel morphologic processes of a highly sinuous bend approaching neck cutoff by bank erosion in the middle Yangtze River显示文摘The distal reach of the Lower Jingjiang River(LJR)in the middle of the Yangtze River consists of five adjacent bends,among which the Qigongling Bend is a U-shaped meander with a mean sinuosity of 2.2 and the narrowest neck 525 m in width.This bend is slowly approaching neck cutoff owing to progressive bank erosion.An abnormal phenomenon has occurred in this bend since the Three Gorges Reservoir(TGR)began to operate in 2003 which is erosion in the inner bank zone and deposition in the outer bank zone.This problem has not been fully understood because of the interplay of changes in water-sediment,bank erosion,and artificial bank revetment.In this study,aerial and remote sensing images,hydrological data,channel topography,and an existing bank erosion model are used to reveal channel morphodynamics of this bend and the trend of the potential neck cutoff induced by bank erosion.The study results show that the clear water released from the TGR has provided by forcefully eroded the point bar of inner bank but failed to scour the outer bank due to the protection of bank revetment since the 1990 s.Thus far,the outer bank zone near the bend apex has increasingly widened in conjunction with the formation of 2 emerging sand bars.Consequently,the thalweg of the main channel has laterally shifted toward the inner bank by roughly 800 m.More severely,the rate of bank retreat on the upstream side of the bend neck was about 4.5 m/yr in 2010-2019,but the downstream side of this neck was experienced slight deposition.Bank erosion could be accelerated by progressively increasing erosion and eventually trigger the occurrence of neck cutoff in the next few decades,thereby significantly altering the quasi-equilibrium regime of channel morphodynamics in the LJR. | Zhiwei Li Hanyuan Yang Junqiang Xia Meirong Zhou Shanshan Deng Yingzhen Wang | 2021 | International Journal of Sediment Research2021，36，4： | 5 |
| 3 | A DFT study on PtMo resistance to SO_2 poisoning显示文摘Pt is a catalyst in proton exchange membrane fuel cell (PEMFC), and its activity will be degraded in the air due to the existence of SOx impurities. On strategy is introducing of Mo into the Pt catalyst because it can improve the SOx -tolerance capacity. Based on the aforementioned phenomenon, a density function theory (DFT) study on SO x adsorbed on Pt(111) and PtMo(111) was performed to enhance Pt catalytic activity. The adsorption energy of adsorbed species, the net change, partial density of state (PDOS), and d-band center were calculated and analyzed comparatively. The results show that the presence of Mo-atom weakens the S-Pt bond strength and reduces the adsorption energies for SO2 , S and SO3 on PtMo(111). Moreover, the Mo atom weakens the effects of SO2 on the PtMo(111) electronic structure and makes the catalyst maintains its original electronic structure after SO2 adsorption as compared with Pt(111). | XIA MeiRong LIU Ying LI Li XIONG Kun QI XueQiang YANG LinJiang HU BaoShan XUE Yun WEI ZiDong | 2013 | Science China Chemistry2013，56，7： | 4 |
| 4 | Curcumin-incorporated 3D bioprinting gelatin methacryloyl hydrogel reduces reactive oxygen species-induced adipose-derived stem cell apoptosis and improves implanting survival in diabetic wounds显示文摘Background:Gelatin methacryloyl(GelMA)hydrogels loaded with stem cells have proved to be an effective clinical treatment for wound healing.Advanced glycation end product(AGE),interacting with its particular receptor(AGER),gives rise to reactive oxygen species(ROS)and apoptosis.Curcumin(Cur)has excellent antioxidant activity and regulates intracellular ROS production and apoptosis.In this study,we developed a Cur-incorporated 3D-printed GelMA to insert into adiposederived stem cells(ADSCs)and applied it to diabetic wounds.Methods:GelMA hydrogels with Cur were fabricated and their in vitro effects on ADSCs were investigated.We used structural characterization,western blot,ROS and apoptosis assay to evaluate the antioxidant and anti-apoptotic activity,and assessed the wound healing effects to investigate the mechanism underlying regulation of apoptosis by Cur via the AGE/AGER/nuclear factor-κB(NF-κB)p65 pathway.Results:A 10%GelMA scaffold exhibited appropriate mechanical properties and biocompatibility for ADSCs.The circular mesh structure demonstrated printability of 10%GelMA and Cur-GelMA bioinks.The incorporation of Cur into the 10%GelMA hydrogel showed an inhibitory effect on AGEs/AGER/NF-κB p65-induced ROS generation and ADSC apoptosis.Furthermore,Cur-GelMA scaffold promoted cell survival and expedited in vivo diabetic wound healing.Conclusions:The incorporation of Cur improved the antioxidant activity of 3D-printed GelMA hydrogel and mitigated AGE/AGER/p65 axis-induced ROS and apoptosis in ADSCs.The effects of scaffolds on wound healing suggested that Cur/GelMA-ADSC hydrogel could be an effective biological material for accelerating wound healing. | Sizhan Xia Tingting Weng Ronghua Jin Min Yang Meirong Yu Wei Zhang Xingang Wang Chunmao Han | 2022 | Burns & Trauma2022，10，1： | 4 |
| 5 | Effects of substrate and transfer on CVD-grown graphene over sapphire-induced Cu films显示文摘We differentiated the effects of Cu films deposited on single crystalline a-,r-,and c-plane sapphire substrates upon graphene films synthesized with atmospheric pressure chemical vapor deposition(CVD).The data illustrate that the realization of high-crystalline Cu film is dependent not only on the crystallinity of underlying substrate,but also on the symmetric match of crystallographic geometry between metal film and substrate.We also systematically investigated the effects of PMMA removal on the Raman ID/IG and IG/I2D values of transferred graphene.The results reveal that different PMMA removal methods do not alter the ID/IG values;instead,the residue of PMMA increases the IG/I2D values and the thermal decomposition of PMMA leads to higher IG/I2D values than the removal of PMMA with acetone.The effects of PMMA removal on variations of the Raman spectra are also discussed. | HU BaoShan WEI ZiDong AGO Hiroki JIN Yan XIA MeiRong LUO ZhengTang PAN QingJiang LIU YunLing | 2014 | Science China Chemistry2014，57，6： | 4 |
| 6 | Chromosome-level Genomes Reveal the Genetic Basis of Descending Dysploidy and Sex Determination in Morus Plants显示文摘Multiple plant lineages have independently evolved sex chromosomes and variable karyotypes to maintain their sessile lifestyles through constant biological innovation.Morus notabilis,a dioecious mulberry species,has the fewest chromosomes among Morus spp.,but the genetic basis of sex determination and karyotype evolution in this species has not been identified.In this study,three high-quality genome assemblies were generated for Morus spp.[including dioecious M.notabilis(male and female)and Morus yunnanensis(female)]with genome sizes of 301–329 Mb and were grouped into six pseudochromosomes.Using a combination of genomic approaches,we found that the putative ancestral karyotype of Morus species was close to 14 protochromosomes,and that several chromosome fusion events resulted in descending dysploidy(2n=2x=12).We also characterized a~6.2-Mb sex-determining region on chromosome 3.Four potential male-specific genes,a partially duplicated DNA helicase gene(named MSDH)and three Ty3_Gypsy long terminal repeat retrotransposons(named MSTG1/2/3),were identified in the Y-linked area and considered to be strong candidate genes for sex determination or differentiation.Population genomic analysis showed that Guangdong accessions in China were genetically similar to Japanese accessions of mulberry.In addition,genomic areas containing selective sweeps that distinguish domesticated mulberry from wild populations in terms of flowering and disease resistance were identified.Our study provides an important genetic resource for sex identification research and molecular breeding in mulberry. | Zhongqiang Xia Xuelei Dai Wei Fan Changying Liu Meirong Zhang Peipei Bian Yuping Zhou Liang Li Baozhong Zhu Shuman Liu Zhengang Li Xiling Wang Maode Yu Zhonghuai Xiang Yu Jiang Aichun Zhao | 2022 | Genomics, Proteomics & Bioinformatics2022，20，6： | 1 |
| 7 | Identifying the Zn-Co binary as a robust bifunctional electrocatalyst in oxygen reduction and evolution reactions via shifting the apexes of the volcano plot显示文摘The performance of an electrocatalyst is closely correlated with the binding strength of key oxygencontaining intermediates,i.e.,*OOH,*O and*OH,in the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Facile strategies to achieve favorable binding strength of these oxygen-containing species are urgently demanded,yet it still remains great challenges.Herein,the Zn-Co bimetallic isolation,which serves as an ideal model,is studied systematically by the density functional theory(DFT).Reaction activity volcano plots are built from 48 models,among them the ZnCoN6-gra(I)configuration is confirmed to be the most stable,featured of the strongest interaction with the oxygen-containing species.Optimal △G*O(free energy change of an atomic oxygen containing intermediate)is facilitated,which effectively drifts the volcano peaks of ORR and OER closer to each other,enabling promising bifunctional catalyst.Moreover,the small overpotential in the simulation of protonation and oxidation by hydroxy groups rationalizes the durability of the catalyst in both acid and alkaline media. | Jing Wang Rui Xu Yuling Sun Qian Liu Meirong Xia Yan Li Faming Gao Yufeng Zhao John S.Tse | 2021 | Journal of Energy Chemistry2021，30，4： | 1 |
| 8 | Two-dimensional modeling of channel evolution under the influence of large-scale river regulation works显示文摘In the middle and lower reaches of alluvial rivers, various kinds of river regulation projects affecting natural channel evolution often are distributed due to the requirements of flood control, navigation,and channel stability. However, the influence of large-scale river regulation works on fluvial processes is not fully known. Therefore, a two-dimensional(2D) morphodynamic model has been improved to address this problem. The new detailed procedure is presented in this paper:(i) First, each node in the study domain was labeled using a specified point code to distinguish the zones with or without regulation works;and(ii) second, a 2D model was improved to consider the effect of river regulation works. In the refined model, the modules of sediment transport and bed deformation were treated separately in different zones. In the unprotected zones, both bed deposition and erosion were likely to occur. In the protected zones, bed erosion could not occur owing to the protection provided by the river regulation works, unless there was a deposition layer newly formed over the previous simulation periods. The observed data of the years 2004 and 2008 were used to calibrate and verify the improved 2D morphodynamic model which was applied in a 68-km-long reach of the Middle Yangtze River. Satisfactory results were obtained indicating that the improved model can better simulate the process of sediment transport and the morphology adjustment in three central bars in the study reach. | Meirong Zhou Junqiang Xia Shanshan Deng Zhiwei Li | 2022 | International Journal of Sediment Research2022，37，4： | 0 |
| 9 | Variation in reach-averaged bankfull discharge in the Yellow River Estuary in recent years显示文摘The Yellow River Estuary(YRE)alternatively experienced channel aggradation and degradation during the period 1990-2016.To study the variation in flood discharge capacity during the process of river bed evolution,bankfull characteristic parameters were investigated on the basis of measured hydrological data and surveyed cross-sectional profiles,which was crucial for comprehending the processes and the key factors to cause these rapid changes.A reach-averaged method was presented in this study in order to calculate the characteristic bankfull parameters in the YRE,and this method integrated the geometric mean using the logarithmic transformation with a weighted mean based on the distance between the two successive sections.The reach-averaged bankfull parameters in the tail reach of the Yellow River Estuary(the Lijin-Xihekou reach)during the period 1990-2016 were then calculated.Calculated results indicated that the adoption of a concept of reach-averaged bankfull discharge was much more representative than the cross-sectional bankfull discharge,and the results also indicated that bankfull discharges decreased during the process of channel aggradation,and increased during the process of channel degradation.Finally,an empirical formula and a delayed response function were established between the reach-averaged bankfull discharge and the previous 4-year average fluvial erosion intensity during flood seasons,and both of them were adopted to reproduce the reach-averaged bankfull discharges,and calculated results showed high correlations(R^(2)>0.8)of these two methods. | Zhuoyuan YANG Junqiang XIA Meirong ZHOU Shanshan DENG Zenghui WANG Zhiwei LI | 2021 | Frontiers of Earth Science2021，15，3： | 0 |
| 10 | One-dimensional morphodynamic model for retrogressive erosion based on a sediment entrainment theory at high flow velocity显示文摘Retrogressive erosion is a high-speed erosion process that usually occurs during the rapid release of stored water in reservoirs built on sandy rivers.Retrogressive erosion has been utilized in the practice of reservoir sedimentation control,but accurate prediction of the bed deformation process by numerical models has rarely been reported.The current study presents a one-dimensional morphodynamic model for simulating the evolution process of retrogressive erosion induced by high-velocity flows on steep slopes.The governing equations apply a Cartesian coordinate system with a vertically oriented z axis.The bed surface gradient and friction terms in the flow equations include correction factors to take account of the effects of high slope on flow movement.The net vertical sediment flux term in the sediment transport and bed deformation equations is calculated using an equation of erosion velocity.Particularly,this equation is based on an empirical relation between the sediment entrainment rate and the Shields parameter in contrast to the traditional sediment transport capacity,and the critical Shields parameter is modified by taking into account the permeability of the sediment layer and the stability of particles on a slope.The feedback of scoured sediment on the flow movement is considered by additional terms in the governing equations.Flume experiments of retrogressive erosion in literature were simulated to validate the model.The temporal variations of the longitudinal profiles of the free surface and channel bed and the sediment transport rate were well predicted.The algorithm calculating sediment entrainment in the proposed model also was validated for an experiment measuring entrainment rate from the literature.More importantly,it was found that the morphodynamic model using the sediment transport capacity equation predicts the trend of cumulative erosion contrary to the measurements,while results of the proposed model can follow a similar trend with the observed data in the retrogressive erosion process. | Zenghui Wang Junqiang Xia Meirong Zhou Shanshan Deng Tao Li | 2021 | International Journal of Sediment Research2021，36，2： | 0 |
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