一种简易的硫辅助方法制备多孔蜂窝状的铁超小原子簇和单原子Fe/g-C3N4

超小原子簇和单原子分散的活性位点(USCAD)催化剂由于其高原子利用率、高活性、高稳定性等优点,成为多相催化领域一个新兴的研究热点.USCAD通常由载体缺陷、配体和分子筛或金属有机框架的孔道和笼锚定.而制备高密度的USCAD催化剂需要载体上有足够的锚定位点.石墨相氮化碳(g-C3N4)具有高稳定性、高密度且均匀分散的氮原子,是制备USCAD催化剂的理想载体.但是传统热解法制备的金属/g-C3N4催化剂通常为块体结构,会导致金属物种被严重包覆,进而导致催化活性下降.加入固体模板可以制备得到多孔金属g-C3N4催化剂,但是后续复杂的除模板过程制约了其实际应用.因此,开发一种简易的无模板方法制备USCAD金属/g-C3N4催化剂具有重要意义.本工作开发了一种简易的硫辅助热解法制备得到蜂窝状结构的高密度(Fe载量为17.7wt%)USCADFe/g-C3N4催化剂.其多孔蜂窝状结构使催化剂能够暴露更多的USCADFe活性位点,增加了活性位点与反应物的可接近性.通过球差电镜和同步辐射X射线吸收技术证明了Fe物种的分散形式.硫辅助热解法只需要在热解铁盐/三聚氰胺前驱体中加入适量的硫源即可得到蜂窝状的USCAD Fe/g-C3N4催化剂.硫元素作为一种"牺牲载体"通过与铁离子配位促进铁物种在前驱体混合物中分散,经过高温煅烧后以SO2的形式释放而不残留在催化剂中,免除了后续的除模板过程.通过TG-MS,XPS和IR等手段证明了硫元素在热解过程中的状态变化.这种硫辅助热解法表现出非常好的普适性,改变硫源种类(硫脲、硫粉、硫氰酸铵)和铁盐种类都可以得到具有蜂窝状孔道结构的USCADFe/g-C3N4催化剂.将催化剂应用于高级氧化过程可以高效降解各种有机污染物(苯酚、亚甲基蓝、亚甲基橙、罗丹明B),催化剂性能远远优于文献报道的其它Fe基催化剂和传统热解法制备的Fe/g-C3N4催化剂.该硫辅助热解法为无模板法制备纳米多孔USCAD金属/g-C3N4催化剂开辟了一条简易可行的途径.

CO_(2)消除镓氢物种提升Ga_(2)O_(3)/SiO_(2)丙烷脱氢反应性能

丙烯是一种基础石油化工原料,在全球石油化工生产中占有重要地位.以丙烯为原料可生产许多石油化学品,如丙烯腈、环氧丙烷和聚丙烯等.经济快速发展带动了丙烯下游衍生物产业的发展,进而增加了对丙烯的需求量,因此尽管近年来丙烯产能逐年上升,丙烯产量与需求量之间仍存在较大缺口.传统的丙烯生产路径主要是石脑油蒸汽裂解和重质油催化裂化.然而,随着石油资源的短缺和页岩气的发展,丙烷脱氢作为一种直接生产丙烯的技术,成为丙烯生产领域的研究热点.近年来,镓基催化剂由于其较少的积碳和较高的催化活性受到了越来越多的关注.镓基催化剂在丙烷脱氢反应中的活性位点也得到了更多研究.在镓基催化剂中,镓氧化物具有丙烷脱氢活性,而丙烷脱氢反应过程中产生的镓氢(Ga^(δ+)-Hx)物种不稳定,且会造成丙烯选择性降低,导致丙烯产率降低.因此,反应过程中原位消除镓氢物种对于提高丙烷脱氢反应性能具有非常重要的意义.本文将CO_(2)作为温和氧化剂引入Ga_(2)O_(3)/SiO_(2)催化的丙烷脱氢反应中,促进不利的中间产物Ga^(δ+)-Hx的转化,再生丙烷脱氢的活性位点Ga^(3+)-O,从而提高催化性能.原位红外光谱实验结果表明,CO_(2)可有效消除Ga^(δ+)-Hx.在不同反应温度下,引入CO_(2)可显著提高Ga_(2)O_(3)/SiO_(2)催化丙烷脱氢的转化率,特别是选择性.反应4.5 h时,3Ga_(2)O_(3)/SiO_(2)催化丙烷脱氢的选择性从93%降低到89%;引入CO_(2)后,丙烯选择性可提高到并维持在93%.Ga_(2)O_(3)负载量由3 wt%提高到10 wt%时,引入CO_(2)仍可促进反应性能.当CO_(2):C3H8由0.5增加到3时,引入CO_(2)带来的反应性能提升基本相同.同时,引入CO_(2)大大减少反应过程中产生的积碳.本文对镓基催化剂丙烷脱氢活性中心的认识和提高丙烷脱氢反应性能提供了新方向.

Enhanced inhibitory control during re-engagement processing in badminton athletes:An event-related potential study

Purpose:The purpose of present study was to investigate the impact of sport experience on response inhibition and response re-engagement in expert badminton athletes during the stop-signal task and change-signal task.Methods:A total of 19 badminton athletes and 20 nonathletes performed both the stop-signal task and change-signal task.Reaction times(RTs)and event-related potentials were recorded and analyzed.Results:Behavioral results indicated that badminton athletes responded faster than nonathletes to go stimuli and to change signals,with faster change RTs and change-signal RTs,which take into consideration the variable stimulus onset time mean.During successful change trials in the change-signal task,the amplitudes of the event-related potential components N2 and P3 were smaller for badminton athletes than for nonathletes.Moreover,change-signal RTs and N2 amplitudes as well as change RTs and P3 amplitudes were significantly correlated in badminton athletes.A significant correlation was also found between the amplitude of the event-related potential component N1 and response accuracy to change signals in badminton athletes.Conclusion:Moderation of brain cortical activity in badminton athletes was more associated with their ability to rapidly inhibit a planned movement and re-engage with a new movement compared with nonathletes.The superior inhibitory control and more efficient neural mechanisms in badminton athletes compared with nonathletes might be a result of badminton athletes’ professional training experience.

Enhancement of hydrogenation kinetics and thermodynamic properties of ZrCo1-xCrx(x=0-0.1)alloys for hydrogen storage

The vacuum arc melting method was used to prepare ZrCo1-xCrx(x=0,0.025,0.05,0.075,0.1)alloys.Afterward,the crystal structure,hydrogenation kinetics,thermodynamic properties,and disproportionation performance of ZrCo1-xCrx(x=0-0.1)alloys were investigated.The x-ray diffraction spectra demonstrated that ZrCo1-xCrx(x=0-0.1)alloys contained ZrCo and ZrCo2 phases,and their corresponding hydrides consisted of ZrCoH3 and ZrH phases.The activation behaviors of Cr-substituted samples were significantly promoted.The activation time of ZrCo was 7715 s while that of ZrCo0.9Cr0.1 was 195 s.The improvement of kinetics can be attributed to the catalytic hydrogenation of ZrCr2.The activation energy for the hydrogenation of ZrCo was 44.88-kJ·mol^-1 H2 and decreased to 40.34-kJ·mol^-1 H2 for ZrCo0.95Cr0.05.The plateau pressure and width of the pressure-composition-temperature curves decreased slightly as Cr content increased.The extent of disproportionation of ZrCo was 83.68%after being insulated at 798 K for 10 h and decreased slightly to 70.52%for ZrCo0.9Cr0.1.The improvement of anti-disproportionation performance can be attributed to increase in the activation energy of disproportionation from 167.46-kJ·mol^-1 H2 for ZrCo to 168.28-kJ·mol^-1 H2 for ZrCo0.95Cr0.05.

Measurement Uncertainty of Blade Surface by Coordinates Measuring Machines in Rotation and Parallel Sampling Modes

This paper aims to investigate the measurement uncertainty of blade surface by coordinates measuring machines (CMMs) in different sampling modes.Two different sampling methods for the blade surface, which are the parallel mode and the rotation mode, are studied to examine their measurement uncertainty.The fundamental principles and operational processes of the two modes are presented and discussed.The measurements were performed on a twisted-face blade, and data processing was also conducted to fit the cross-section profile both of the base surface and back surface separately.Then the measurement uncertainties of two sampling methods were evaluated on different parts of the blade surface in terms of the surface profile’s curvature and twist rate.It is found that the measurement of blade surface by CMMs shows much uncertainty for both of the sampling modes because of the complexity of the blade surface.The back surface’s measurement uncertainty is larger than that of the base surface.The measurement uncertainty of cross-section profiles on the top blade surface is larger than that of the bottom blade surface.In addition, the difference between the measurement uncertainties of two sampling methods is small, especially for the base blade surface.The research means that both sampling methods can be a practical application choice for the measurement of blade surface by CMMs.

Study on the Third-order Nonlinear Optical Properties of bis(tetraethylammonium) bis(1,3-dithiole-2-thione-4,5-dithiolato)cadium

A dmit2- salt: bis(tetraethylammonium)bis(1,3-dithiole-2-thione-4,5-dithiolato)cadium (CADMIT) was synthesized. The Optical Kerr Effect (OKE) signal of its acetonitrile solution was measured by femtosecond optical Kerr gate technique. Using CS2 OKE signal as reference signal measured under identical conditions, the third-order optical nonlinear susceptibility, c(3), of the sample solution was obtained to be about 2.98 x 10-14 esu at the concentration of 1.57 x 10-3 M. The second-order hyperpolarizability of its molecular was estimated to be as large as 1.23 x 10-32 esu. Its response time was about 195 fs, which is believed to be the contribution from the delocalized electrons.

Prospects of sediment deposition at small watershed scale in the black soil region of Northeast China: A mini review

Sediment deposition is one of the most significant processes in small watersheds characterized by gentle long hillslopes in the black soil(Mollisol)region of Northeast China, as indicated by severe ephemeral gully and gully erosion on hillslopes and very low sediment concentrations in river systems.Few reviews have been conducted to summarize the related research in this region. The objectives of this review were to identify the potential factors influencing sediment deposition, review related studies, and propose future research needs in the black soil region of Northeast China. Sediment deposition is controlled by the deficit between sediment transport capacity of flow and sediment load. Hence, all factors affecting flow transport capacity and sediment load directly affect sediment deposition. For a specific small watershed, the change in slope gradient along the flow path is the key factor affecting sediment deposition. Shelterbelts, ridge tillage systems, terraces, grass strips, road distribution, ponds and reservoirs, and land-use patterns also influence the spatial distribution and rate of deposition. The trace method has been widely used to quantify sediment deposition in this region. The results of cesium-137(^(137)Cs),lead-210(^(210)Pb), and magnetic susceptibility reveal that serious deposition occurs on the back and foot slopes. Distinct deposition occurs in front of contour shelterbelts. Future studies should focus on the methodology, spatial and temporal variations, dominant influencing factors and their mechanisms, and the potential effects on land productivity within specific small watersheds and across the black soil region. This review provides insights into the sediment deposition process in small watersheds characterized by gentle, long hillslopes.

历史视角下劳动力市场的性别差异——2023年诺贝尔经济学奖学术贡献梳理与评价

劳动力市场是经济学研究的重要内容。克劳迪娅·戈尔丁基于历史追溯视角,运用大量经济史数据展示了女性参与劳动力市场的演变过程,对理解女性参与劳动力市场的模式以及劳动力市场的性别差异做出了开创性贡献。2023年诺贝尔经济学奖授予克劳迪娅·戈尔丁,表彰其研究成果增进了对女性劳动力市场结果的理解。

Weak SARS-CoV-2-specific responses of TIGIT-expressing CD8^(+)T cells in people living with HIV after a third dose of a SARS-CoV-2 inactivated vaccine

Background:T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains(TIGIT),an inhibitory receptor expressed on T cells,plays a dysfunctional role in antiviral infection and antitumor activity.However,it is unknown whether TIGIT expression on T cells influences the immunological effects of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)inactivated vaccines.Methods:Forty-five people living with HIV(PLWH)on antiretroviral therapy(ART)for more than two years and 31 healthy controls(HCs),all received a third dose of a SARS-CoV-2 inactivated vaccine,were enrolled in this study.The amounts,activation,proportion of cell subsets,and magnitude of the SARS-CoV-2-specific immune response of TIGIT^(+)CD4^(+)and TIGIT^(+)CD8^(+)T cells were investigated before the third dose but 6 months after the second vaccine dose(0W),4 weeks(4W)and 12 weeks(12W)after the third dose.Results:Compared to that in HCs,the frequency of TIGIT^(+)CD8^(+)T cells in the peripheral blood of PLWH increased at 12W after the third dose of the inactivated vaccine,and the immune activation of TIGIT^(+)CD8^(+)T cells also increased.A decrease in the ratio of both T naïve(T_(N))and central memory(T_(CM))cells among TIGIT^(+)CD8^(+)T cells and an increase in the ratio of the effector memory(T_(EM))subpopulation were observed at 12W in PLWH.Interestingly,particularly at 12W,a higher proportion of TIGIT^(+)CD8^(+)T cells expressing CD137 and CD69 simultaneously was observed in HCs than in PLWH based on the activation-induced marker assay.Compared with 0W,SARS-CoV-2-specific TIGIT^(+)CD8^(+)T-cell responses in PLWH were not enhanced at 12W but were enhanced in HCs.Additionally,at all time points,the SARS-CoV-2-specific responses of TIGIT^(+)CD8^(+)T cells in PLWH were significantly weaker than those of TIGIT-CD8^(+)T cells.However,in HCs,the difference in the SARS-CoV-2-specific responses induced between TIGIT^(+)CD8^(+)T cells and TIGIT-CD8^(+)T cells was insignificant at 4W and 12W,except at 0W.Conclusions:TIGIT expression on CD8^(+)T cells may hinder the T-cell immune response to a booster dose of an inactivated SARS-CoV-2 vaccine,suggesting weakened resistance to SARS-CoV-2 infection,especially in PLWH.Furthermore,TIGIT may be used as a potential target to increase the production of SARS-CoV-2-specific CD8^(+)T cells,thereby enhancing the effectiveness of vaccination.

Durable natural killer cell response after three doses of SARS-CoV-2 inactivated vaccine in HIV-infected individuals

Background:Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccine can induce a potent cellular and humoral immune response to protect against SARS-CoV-2 infection.However,it was unknown whether SARS-CoV-2 vaccination can induce effective natural killer(NK)cell response in people living with human immunodeficiency virus(PLWH)and healthy individuals.Methods:Forty-seven PLWH and thirty healthy controls(HCs)inoculated with SARS-CoV-2 inactivated vaccine were enrolled from Beijing Youan Hospital in this study.The effect of SARS-CoV-2 vaccine on NK cell frequency,phenotype,and function in PLWH and HCs was evaluated by flow cytometry,and the response of NK cells to SARS-CoV-2 Omicron Spike(SARS-2-OS)protein stimulation was also evaluated.Results:SARS-CoV-2 vaccine inoculation elicited activation and degranulation of NK cells in PLWH,which peaked at 2 weeks and then decreased to a minimum at 12 weeks after the third dose of vaccine.However,in vitro stimulation of the corresponding peripheral blood monocular cells from PLWH with SARS-2-OS protein did not upregulate the expression of the aforementioned markers.Additionally,the frequencies of NK cells expressing the activation markers CD25 and CD69 in PLWH were significantly lower than those in HCs at 0,4 and 12 weeks,but the percentage of CD16^(+)NK cells in PLWH was significantly higher than that in HCs at 2,4 and 12 weeks after the third dose of vaccine.Interestingly,the frequency of CD16^(+)NK cells was significantly negatively correlated with the proportion of CD107a^(+)NK cells in PLWH at each time point after the third dose.Similarly,this phenomenon was also observed in HCs at 0,2,and 4 weeks after the third dose.Finally,regardless of whether NK cells were stimulated with SARS-2-OS or not,we did not observe any differences in the expression of NK cell degranulation markers between PLWH and HCs.Conclusions:SARS-CoV-2 vaccine elicited activation and degranulation of NK cells,indicating that the inoculation of SARS-CoV-2 vaccine enhances NK cell immune response.

Comparative genomics reveals the diversification of triterpenoid biosynthesis and origin of ocotilloltype triterpenes in Panax

Gene duplication is assumed to be the major force driving the evolution of metabolite biosynthesis in plants.Freed from functional burdens,duplicated genes can mutate toward novelties until fixed due to selective fitness.However,the extent to which this mechanism has driven the diversification of metabolite biosynthesis remains to be tested.Here we performed comparative genomics analysis and functional characterization to evaluate the impact of gene duplication on the evolution of triterpenoid biosynthesis using Panax species as models.Wefound that whole-genome duplications(WGDs)occurred independently in Araliaceae and Apiaceae lineages.Comparative genomics revealed the evolutionary trajectories of triterpenoid biosynthesis in plants,which was mainly promoted by WGDs and tandem duplication.Lanosterol synthase(LAS)was likely derived from a tandemduplicate of cycloartenol synthase that predated the emergence of Nymphaeales.Under episodic diversifying selection,the LAS gene duplicates produced by g whole-genome triplication have given rise to triterpene biosynthesis in core eudicots through neofunctionalization.Moreover,functional characterization revealed that oxidosqualene cyclases(OSCs)responsible for synthesizing dammarane-type triterpenes in Panax species were also capable of producing ocotilloltype triterpenes.Genomic and biochemical evidence suggested that Panax genes encoding the above OSCs originated from the specialization of one OSC gene duplicate produced from a recent WGD shared by Araliaceae(Pg-b).Our results reveal the crucial role of gene duplication in diversification of triterpenoid biosynthesis in plants and provide insight into the origin of ocotillol-type triterpenes in Panax species.

Targeting cancer stem cell pathways for cancer therapy

Since cancer stem cells(CSCs)were first identified in leukemia in 1994,they have been considered promising therapeutic targets for cancer therapy.These cells have self-renewal capacity and differentiation potential and contribute to multiple tumor malignancies,such as recurrence,metastasis,heterogeneity,multidrug resistance,and radiation resistance.The biological activities of CSCs are regulated by several pluripotent transcription factors,such as OCT4,Sox2,Nanog,KLF4,and MYC.In addition,many intracellular signaling pathways,such as Wnt,NF-κB(nuclear factor-κB),Notch,Hedgehog,JAK-STAT(Janus kinase/signal transducers and activators of transcription),PI3K/AKT/mTOR(phosphoinositide 3-kinase/AKT/mammalian target of rapamycin),TGF(transforming growth factor)/SMAD,and PPAR(peroxisome proliferator-activated receptor),as well as extracellular factors,such as vascular niches,hypoxia,tumor-associated macrophages,cancer-associated fibroblasts,cancer-associated mesenchymal stem cells,extracellular matrix,and exosomes,have been shown to be very important regulators of CSCs.Molecules,vaccines,antibodies,and CAR-T(chimeric antigen receptor T cell)cells have been developed to specifically target CSCs,and some of these factors are already undergoing clinical trials.This review summarizes the characterization and identification of CSCs,depicts major factors and pathways that regulate CSC development,and discusses potential targeted therapy for CSCs.

Relationship between topography and the distribution of understory vegetation in a Pinus massoniana forest in Southern China

The poor growth of understory vegetation and the severe losses of soil and water in Pinus massoniana forests have recently become serious concerns in an area in southern China with eroded red soil.The influence of topography on the spatial distribution of vegetation,however,has received little attention.This study combined several multivariate analyses to discern the complicated relationship between understory vegetation and topography.Thirty-six plots(10 m×10 m)were sampled in a field survey of the vegetation and topography in the central red-soil region.The distributions of the understory vegetation differed significantly amongst the topographies.Most plants grew in gullies,and few grew on ridges.The low coverage(25.2%)and number of species(5 per plot)of the vegetation on ridges was due to serious soil erosion.Surface curvature and slope aspect were the first and second most important topographic factors,respectively,affecting the distribution of the vegetation.The relationship between topography and distribution could be described by a linear model.Surface curvature or slope aspect alone,however,could only explain 22.2-59.2%of the variance in distribution.The adaptation of vegetation to specific topographies should be considered for restorations of P.massoniana forests in the study area.The results of this study will be helpful for selecting potential sites for seeding and vegetation restoration to improve the ecology of the study area.Further studies will be needed to identify the mechanism of the distribution of the understory vegetation in these P.massoniana forests.

Is the runoff coefficient increasing or decreasing after ecological restoration on China’s Loess Plateau?

The“Grain for Green”project(GGP)was launched in 1999 on China’s Loess Plateau to reduce soil erosion,which had far-reaching impacts on the local eco-hydrological processes.In this study,we use monthly runoff depth and precipitation datasets spanning 1961 to 2015 for 16 primary basins of the plateau to reveal changes in runoff generation capacity before and after the GGP.We use a Budyko-based elasticity method to calculate the runoff depth(R_(1))and runoff coefficient(C_(1))exclusively attributable to land use/cover change.Results indicate that the mean annual runoff coefficients(Co)decline by 26%—76%from the periods 1961—1999 to 2000—2015.The annual observed runoff depth(Ro)and C_(0)for 75%of basins show significant downward trends during 1961—1999;after the implementation of the GGP,both annual Ro and annual Co for over 50%of basins show upward trends.The study further finds that the increase of erosive rainfall during the period 2000-2015,whose mean increasing rate reaches 4.6 mm/year,is the main reason for the upward trends of Ro and Co.After removing the effect of precipitation variation during this period,we find that 11 out of 16 basins show decreased trends for Cj,with the downward rate between 2.4%and 6.0%per year.The reduction rate in semi-arid areas is about four times the rate in semi-humid areas.The results remind us to consider the carrying capacity of local water resources when implementing soil and water conservation measures across the Loess Plateau.

Impacts of nano-scale pore structure and organic amine assembly in porous silica on the kinetics of CO_(2) adsorptive separation

Nano structure including pore structure and amine assembly is critical for improving sorption and desorption kinetics for adsorptive CO_(2) separation.The present work delineates(1)the influence of the nano-scale pore structure of amine-functionalized solid sorbents,and(2)effect of changing the assembly of amine molecules on surface of nano-porous SiO_(2) on the rates of adsorption and desorption of CO_(2).50PEI-MSN sorbent with inverted cone-shaped pores was prepared by using mesoporous silica nanospheres(MSN)with inverted cone-shaped pores for the loading of polyethyleneimine(PEI).Co-structure-directing(CSD)method was used to synthesize the sorbent with arranged amine assembly at nano-scale(2N-CSD).By comparison with 50PE卜SBA15 as a benchmark sorbent,both sorbents have improved sorption and desorption kinetics.There are significant effects of nano pore structure and amine assembly on the sorption and desorption kinetics.The inverted cone-shaped pores in MSN allow loading polymeric amines in their narrower ends and leaving larger pore mouths open for the transport of CO_(2);50PEI-MSN shows a maximum sorption rate of 81.4 mg·g^(-1)·min^(-1) with average sorption rate of 25.4mg·g^(-1)·min^(-1) at 80℃ which are 34%and 59%higher than the corresponding values for 50PEI-SBA15;a maximum desorption rate of 38.4mg·g^(-1)·min^(-1) with average desorption rate of 11.8 mg·g^(-1)·min^(-1) ramping from 30 to 95℃ which are 37%and 156%higher than the corresponding values for 50PEI-SBA15.The arranged monolayer-like amine assembly on surface of nanoporous SiO_(2) likely provides high amine sorption sites through improved accessibility of amine,and 2N-CSD shows a maximum sorption rate of 60.5 mg·g^(-1)·min^(-1),with average sorption rate of 12.8mg·g^(-1)·min^(-1) at 300C which are 108%and 205%higher than the corresponding values for 50PEI-SBA15;a lower maximum desorption rate of 9.7 mg g'1min"1 and average desorption rate of 9.8mg·g^(-1)·min^(-1) ramping from 30 to 95℃ which is 250%higher than the corresponding value for 50PEI-SBA15.The present work demonstrates the importance of tailoring nano-scale pore structure and amine assembly for significantly improving sorption and desorption kinetics of adsorptive CO_(2) separation.

A comprehensive review on coupled processes and mechanisms of soil-vegetation-hydrology, and recent research advances

Research on the coupling of soil,vegetation,and hydrological processes is not only a research hotspot in disciplines such as pedology,ecohydrology and Earth system science but also important for achieving sustainable development.However,scientists from different disciplines usually study the coupling mechanism of soil-vegetation-hydrological processes at very different space and time scales,and the mechanistic connections between different scales are quite few.This article reviewed research advances in coupled soil-vegetation-hydrological processes at different spatial scales—from leaf stomata to watershed and regional scales—and summarized the spatial upscaling methods and modeling approaches of coupled soil-vegetationhydrological processes.We identify and summarize the following coupling processes:(1)carbon-water exchange in leaf stomata and root-soil interface;(2)changes in soil aggregates and profile hydraulic properties caused by plant roots and water movement;(3)precipitation and soil moisture redistribution by plant canopy and root;(4)interactions between vegetation patches and local hydrological process;(5)links between plant community succession and soil development;and(6)links between watershed/regional water budget and vegetation phenology and production.Meanwhile,the limitations and knowledge gaps in the observations,mechanisms,scaling methods,and modeling approaches of coupled soil-vegetation-hydrological processes were analyzed.To achieve a deep integration of various coupling processes across different spatiotemporal scales,future work should strengthen multiscale,multifactor and multiprocess soil-vegetation-hydrology coupling observations and mechanism studies,develop new scaling methods,identify different feedback pathways,and take time-variable plant behavior and soil hydraulic properties into account during modeling.

Modification of YSZ fiber composites by Al_(2)TiO_(5) fibers for high thermal shock resistance

Yttria-stabilized zirconia(YSZ)fiber composites are highly efficient thermal insulating materials;however,the poor thermal shock resistance limits their versatile applications.In the present study,YSZ fiber was mixed directly with Al_(2)TiO_(5)fiber,which had an extremely low thermal expansion coefficient,to prepare YSZ–Al_(2)TiO_(5)(ZAT)fiber composites by compression molding and heat treatment.The minimum thermal expansion coefficient of the prepared ZAT fiber composites was measured to be 7.74×10^(−6)K^(−1),which was 26%lower than that of the YSZ fiber composites(10.42×10^(−6)K^(−1)).It was shown that the prepared ZAT fiber composites maintain the integrity after undergoing 51 thermal shock cycles between 1100℃and room temperature.Whereas,YSZ fiber composites burst immediately after only one thermal shock cycle under the same condition.In addition,the ZAT fiber composites also exhibit considerable mechanical and thermal insulating performance.

Graphene-like h-BN supported polyhedral NiS_(2)/NiS nanocrystals with excellent photocatalytic performance for removing rhodamine B and Cr(Ⅵ)

Human health is deteriorating due to the effluent containing heavy metal ions and organic dyes.Hence,photoreduction of Cr(Ⅵ)to Cr(Ⅲ)and degradation of rhodamine B(RhB)using a novel photocatalyst is particularly important.In this work,h-BN/NiS_(2)/NiS composites were prepared via a simple solvothermal method and a double Z-scheme heterojunction was constructed for efficiently removing RhB and Cr(Ⅵ).The 7 wt-%h-BN/NiS_(2)/NiS composites were characterized via a larger specific surface area(15.12 m^(2)·g^(−1)),stronger light absorption capacity,excellent chemical stability,and high yield of electrons and holes.The experimental result indicated that the photoreduction efficiency of the 7 wt-%h-BN/NiS_(2)/NiS photocatalyst achieved 98.5%for Cr(Ⅵ)after 120 min,which was about 3 times higher than that of NiS_(2)/NiS(34%).However,the removal rate of RhB by the 7 wt-%h-BN/NiS_(2)/NiS photocatalyst reached 80%.This is due to the double Z-scheme heterojunction formed between NiS_(2)/NiS and h-BN,which improved the charge separation efficiency and transmission efficiency.Besides,the influence of diverse photogenerated electron and hole scavengers upon the photoreduction of Cr(Ⅵ)was studied,the results indicated that graphene-like h-BN promoted transportation of photoinduced charges on the surface of the h-BN/NiS_(2)/NiS photocatalyst via the interfacial effects.

Measurement errors on sediment concentration from traditional runoff collection tanks and its correction possibility

Runoff plots are widely used worldwide to monitor water and soil losses.Sediment concentration in runoff collection tank is measured by stirring-sampling procedure,but this method may produce high measurement error due to the uneven mixing of collected sediments with water and soil particle deposition.This study aimed to identify the relationship between actual and measured sediment concentrations,so as to estimate the systematic error of sediment concentration measurement from runoff collection tank by traditional stirring-sampling procedure and the possibility to eliminate it.Four major soils including black soil,silt loess,clay loess,and purple soil in China were used to determine the correlation between the measured and designed sediment concentrations in laboratory.Tested sediment concentration was 1,2,5,8,10,20,50,80,100,200,500,800,and 1000 kg/m^(3),and total sediment-laden water volume was 50 L and 100 L.Five samples were collected successively from collection tank for each treatment and their sediment concentrations were measured by conventional oven-drying method.The results showed that all the measured sediment concentration values were smaller than the designed ones,but both the measured and designed values were linearly correlated significantly with determination coefficients greater than 0.8,generally.In the whole tested concentration range,the systematical error was-0.19 to-319.95 kg/m^(3) and relative error was 0.30%-84.5% for the 4 tested soils and 2 total sediment-laden water volumes.These results indicated a necessity and possibility to correct conventional sediment concentration measurement value.The result is usable to assess and correct the measurement error of sediment concentrations from traditional runoff plot.

Metabolic engineering of Yarrowia lipolytica for scutellarin production

Scutellarin related drugs have superior therapeutic effects on cerebrovascular and cardiovascular diseases.Here,an optimal biosynthetic pathway for scutellarin was constructed in Yarrowia lipolytica platform due to its excellent metabolic potential.By integrating multi-copies of core genes from different species,the production of scutellarin was increased from 15.11 mg/L to 94.79 mg/L and the ratio of scutellarin to the main by-product was improved about 110-fold in flask condition.Finally,the production of scutellarin was improved 23-fold and reached to 346 mg/L in fed-batch bioreactor,which was the highest reported titer for de novo production of scutellarin in microbes.Our results represent a solid basis for further production of natural products on unconventional yeasts and have a potential of industrial implementation.