PM2.5 and PM10 samples were collected at four major cities in the Pearl River Delta （PRD）, South China, during winter and summer in 2002. Six water-soluble ions, Na^＋, NH4＋, K^＋, Cl^-, NO3^- and SO4^2- were measu...PM2.5 and PM10 samples were collected at four major cities in the Pearl River Delta （PRD）, South China, during winter and summer in 2002. Six water-soluble ions, Na^＋, NH4＋, K^＋, Cl^-, NO3^- and SO4^2- were measured using ion chromatography. On average, ionic species accounted for 53.3% and 40.5% for PM2.5 and PM10, respectively in winter and 39.4% and 35.2%, respectively in summer. Secondary ions such as sulfate, nitrate and ammonium accounted for the major part of the total ionic species. Sulfate was the most abundant species followed by nitrate. Overall, a regional pollution tendency was shown that there were higher concentrations of sulfate, nitrate and ammonium in Guangzhou City than those in the other PRD cities. Significant seasonal variations were also observed with higher levels of species in winter but lower in summer. The Asian monsoon system was favorable for removal and diffusion of air pollutants in PRD in summer while highly loading of local industrial emissions tended to deteriorate the air quality as well. NO3^-/SO4^2- ratio indicated that mobile sources have considerably contribution to the urban aerosol, and stationary sources should not be neglected. Besides the primary emissions, complex atmospheric reactions under favorable weather conditions should be paid more attention for the control of primary emission in the PRD region.展开更多
This work examines the influence of preparation methods on the physicochemical properties and catalytic performance of MnOx‐CeO2 catalysts for selective catalytic reduction of NO by NH3 (NH3‐SCR) at low temperature....This work examines the influence of preparation methods on the physicochemical properties and catalytic performance of MnOx‐CeO2 catalysts for selective catalytic reduction of NO by NH3 (NH3‐SCR) at low temperature. Five different methods, namely, mechanical mixing, impregnation,hydrothermal treatment, co‐precipitation, and a sol‐gel technique, were used to synthesizeMnOx‐CeO2 catalysts. The catalysts were characterized in detail, and an NH3‐SCR model reaction waschosen to evaluate the catalytic performance. The results showed that the preparation methodsaffected the catalytic performance in the order: hydrothermal treatment > sol‐gel > co‐precipitation> impregnation > mechanical mixing. This order correlated with the surface Ce3+ and Mn4+ content,oxygen vacancies and surface adsorbed oxygen species concentration, and the amount of acidic sitesand acidic strength. This trend is related to redox interactions between MnOx and CeO2. The catalystformed by a hydrothermal treatment exhibited excellent physicochemical properties, optimal catalyticperformance, and good H2O resistance in NH3‐SCR reaction. This was attributed to incorporationof Mnn+ into the CeO2 lattice to form a uniform ceria‐based solid solution (containing Mn‐O‐Cestructures). Strengthening of the electronic interactions between MnOx and CeO2, driven by thehigh‐temperature and high‐pressure conditions during the hydrothermal treatment also improved the catalyst characteristics. Thus, the hydrothermal treatment method is an efficient and environment‐friendly route to synthesizing low‐temperature denitrification (deNOx) catalysts.展开更多
Accurate determination of the atmospheric particulate matter mass concentration and chemical composition is helpful in exploring the causes and sources of atmospheric enthalpy pollution and in evaluating the rationali...Accurate determination of the atmospheric particulate matter mass concentration and chemical composition is helpful in exploring the causes and sources of atmospheric enthalpy pollution and in evaluating the rationality of environmental air quality control strategies.Based on the sampling and chemical composition data of PM2.5 in different key regions of China in the CARE-China observation network,this research analyzes the environmental air quality data released by the China National Environmental Monitoring Centre during the studied period to determine the changes in the particulate matter mass concentration in key regions and the evolution of the corresponding chemical compositions during the implementation of the Action Plan for Prevention and Control of Air Pollution from 2013-2017.The results show the following.(1)The particulate matter mass concentration in China showed a significant downward trend;however,the PM2.5 annual mass concentration in 64%of cities exceeds the New Chinese Ambient Air Quality Standard(CAAQS)GradeⅡ(GB3095-2012).The region to the east of the Taihang Mountains,the Fenhe and Weihe River Plain and the Urumqi-Changji regions in Xinjiang,all have PM2.5 concentration loading that is still high,and heavy haze pollution occurred frequently in the autumn and winter.(2)During the heavy pollution in the autumn and winter,the concentrations of sulfate and organic components decreased significantly.The mean SO42-concentration in PM2.5 decreased by 76%,12%,81%and 38%in Beijing-Tianjin-Hebei(BTH),the Pearl River Delta(PRD),the Sichuan-Chongqing region(SC)and the Fenhe and Weihe River Plain,respectively.The mean organic matter(OM)concentration decreased by 70%,44%,48%and 31%,respectively,and the mean concentration of NH4+decreased by 68%,1.6%,38%and 25%,respectively.The mean elemental carbon(EC)concentration decreased by 84%and 20%in BTH and SC,respectively,and it increased by 61%and 11%in the PRD and Fenhe and Weihe River Plain,respectively.The mean concentration of mineral and unresolved chemica展开更多
Continuous observation data collected over the whole year of 2004 on a cropland surtace m Tongyu, a senti-arid area of northeastern China （44°25＇N, 122°52＇E）, have been used to investigate the variations...Continuous observation data collected over the whole year of 2004 on a cropland surtace m Tongyu, a senti-arid area of northeastern China （44°25＇N, 122°52＇E）, have been used to investigate the variations of surface albedo and soil thermal parameters, including heat capacity, thermal conductivity and thermal diffusivity, and their relationships to soil moisture. The diurnal variation of surface albedo appears as a U shape curve on sunny days. Surface albedo decreases with the increase of solar elevation angle, and it tends to be a constant when solar elevation angle is larger than 40°. So the daily average surface albedo was computed using the data when solar elevation angle is larger than 40° Mean daily surface albedo is found to decrease with the increase of soil moisture, showing an exponential dependence on soil moisture. The variations of soil heat capacity are small during Julian days 90 300. Compared with the heat capacity, soil thermal conductivity has very gentle variations during this period, but the soil thermal diffusivity has wide variations during the same period. The soil thermal conductivity is found to increase as a power function of soil moisture. The soil thermal diffusivity increases firstly and then decreases with the increase of soil moisture.展开更多
The FAIR principles have been widely cited,endorsed and adopted by a broad range of stakeholders since their publication in 2016.By intention,the 15 FAIR guiding principles do not dictate specific technological implem...The FAIR principles have been widely cited,endorsed and adopted by a broad range of stakeholders since their publication in 2016.By intention,the 15 FAIR guiding principles do not dictate specific technological implementations,but provide guidance for improving Findability,Accessibility,Interoperability and Reusability of digital resources.This has likely contributed to the broad adoption of the FAIR principles,because individual stakeholder communities can implement their own FAIR solutions.However,it has also resulted in inconsistent interpretations that carry the risk of leading to incompatible implementations.Thus,while the FAIR principles are formulated on a high level and may be interpreted and implemented in different ways,for true interoperability we need to support convergence in implementation choices that are widely accessible and(re)-usable.We introduce the concept of FAIR implementation considerations to assist accelerated global participation and convergence towards accessible,robust,widespread and consistent FAIR implementations.Any self-identified stakeholder community may either choose to reuse solutions from existing implementations,or when they spot a gap,accept the challenge to create the needed solution,which,ideally,can be used again by other communities in the future.Here,we provide interpretations and implementation considerations(choices and challenges)for each FAIR principle.展开更多
A laboratory scale experiment of composting in a forced aeration system using pig manure with cornstalks was carried out to investigate the effects of both phosphogypsum and dicyandiamide （DCD, C2 H4 N4 ） as additiv...A laboratory scale experiment of composting in a forced aeration system using pig manure with cornstalks was carried out to investigate the effects of both phosphogypsum and dicyandiamide （DCD, C2 H4 N4 ） as additives on gaseous emissions and compost quality. Besides a control, there were three amended treatments with different amounts of additives. The results indicated that the phosphogypsum addition at the rate of 10% of mixture dry weight decreased NH3 and CH4 emissions significantly during composting. The addition of DCD at the rate of 0.2% of mixture dry weight together with 10% of phosphogypsum further reduced the N20 emission by affecting the nitrification process. Reducing the phosphogypsum addition to 5% in the presence of 0.2% DCD moderately increased the NH3 emissions but not N20 emission. The additives increased the ammonium content and electrical conductivity significantly in the final compost. No adverse effect on organic matter degradation or the germination index of the compost was found in the amended treatments. It was recommended that phosphogypsum and DCD could be used in composting for the purpose of reducing NH3 , CH4 and N20 emissions.0ptimal conditions and dose of DCD additive during composting should be determined with different materials and composting systems in further study.展开更多
Based on observations of urban mass concentration of fine particulate matter smaller than 2.5 μm in diameter （PM2.5）, ground meteorological data, vertical measurements of winds, temperature, and relative humidity ...Based on observations of urban mass concentration of fine particulate matter smaller than 2.5 μm in diameter （PM2.5）, ground meteorological data, vertical measurements of winds, temperature, and relative humidity （RH）, and ECMWF reanalysis data, the major changes in the vertical structures of meteorological factors in the boundary layer （BL） during the heavy aerosol pollution episodes （HPEs） that occurred in winter 2016 in the urban Beijing area were analyzed. The HPEs are divided into two stages： the transport of pollutants under prevailing southerly winds, known as the transport stage （TS）, and the PM2.5 explosive growth and pollution accumulation period characterized by a temperature inversion with low winds and high RH in the lower BL, known as the cumulative stage （CS）. During the TS, a surface high lies south of Beijing, and pollutants are transported northwards. During the CS, a stable BL forms and is characterized by weak winds, temperature inversion, and moisture accumulation. Stable atmospheric stratifica- tion featured with light/calm winds and accumulated moisture （RH 〉 80%） below 250 m at the beginning of the CS is closely associated with the inversion, which is strengthened by the considerable decrease in near-surface air temperat- ure due to the interaction between aerosols and radiation after the aerosol pollution occurs. A significant increase in the PLAM （Parameter Linking Aerosol Pollution and Meteorological Elements） index is found, which is linearly re- lated to PM mass change. During the first 10 h of the CS, the more stable BL contributes approximately 84% of the explosive growth of PM2.5 mass. Additional accumulated near-surface moisture caused by the ground temperature de- crease, weak turbulent diffusion, low BL height, and inhibited vertical mixing of water vapor is conducive to the sec- ondary aerosol formation through chemical reactions, including liquid phase and heterogeneous reactions, which fur- ther increases the PM2.5 concentration levels. Th展开更多
With the development of nuclear energy, large amounts of radionuclides are inevitably released into the natural environment. It is necessary to eliminate radionuclides from wastewater for the protection of environment...With the development of nuclear energy, large amounts of radionuclides are inevitably released into the natural environment. It is necessary to eliminate radionuclides from wastewater for the protection of environment. Nanomaterials have been considered as the potential candidates for the effective and selective removal of radionuclides from aqueous solutions under complicated conditions because of their high specific surface area, large amounts of binding sites, abundant functional groups, pore-size controllable and easily surface modification. This review mainly summarized the recent studies for the synthesis, fabrication and surface modification of novel nanomaterials and their applications in the efficient elimination and solidification of radionuclides,and discussed the interaction mechanisms from batch experiments, spectroscopy analysis and theoretical calculations. The sorption capacities with other materials, advantages and disadvantages of different nanomaterials are compared, and at last the perspective of the novel nanomaterials is summarized.展开更多
We investigated the seasonal and spatial ozone variations in China by using three-year surface ozone observation data from the six Chinese Global Atmosphere Watch(GAW)stations and tropospheric column ozone data from s...We investigated the seasonal and spatial ozone variations in China by using three-year surface ozone observation data from the six Chinese Global Atmosphere Watch(GAW)stations and tropospheric column ozone data from satellite retrieval over the period2010–2012. It is shown that the seasonal ozone variations at these GAW stations are rather different, particularly between the western and eastern locations. Compared with western China, eastern China has lower background ozone levels. However, the Asian summer monsoon(ASM) can transport photochemical pollutants from the southern to the northern areas in eastern China, leading to a northward gradual enhancement of background ozone levels at the eastern GAW stations. Over China, the tropospheric column ozone densities peak during spring and summer in the areas that are directly and/or indirectly affected by the ASM, and the peak time lags from the south to the north in eastern China. We also investigated the regional representativeness of seasonal variations of ozone at the six Chinese GAW stations using the yearly maximum tropospheric column month as indicator.The results show that the seasonal variation characteristics of ozone revealed by the Chinese GAW stations are typical, with each station having a considerable large surrounding area with the ozone maximum occurring at the same month. Ozone variations at the GAW stations are influenced by many complex factors and their regional representativeness needs to be investigated further in a broader sense.展开更多
The aim of this study was to uncover ways to mitigate greenhouse gas（GHG） emissions and reduce energy consumption during the composting process. We assessed the effects of different aeration rates（0, 0.18, 0.36, an...The aim of this study was to uncover ways to mitigate greenhouse gas（GHG） emissions and reduce energy consumption during the composting process. We assessed the effects of different aeration rates（0, 0.18, 0.36, and 0.54 L/（kg dry matter（dm）·min）） and methods（continuous and intermittent） on GHG emissions. Pig feces and corn stalks were mixed at a ratio of 7：1. The composting process lasted for 10 weeks, and the compost was turned approximately every 2 weeks. Results showed that both aeration rate and method significantly affected GHG emissions. Higher aeration rates increased NH3 and N2O losses,but reduced CH4 emissions. The exception is that the CH4 emission of the passive aeration treatment was lower than that of the low aeration rate treatment. Without forced aeration,the CH4 diffusion rates in the center of the piles were very low and part of the CH4 was oxidized in the surface layer. Intermittent aeration reduced NH3 and CH4 losses, but significantly increased N2 O production during the maturing periods. Intermittent aeration increased the nitrification/denitrification alternation and thus enhanced the N2 O production. Forced aeration treatments had higher GHG emission rates than the passive aeration treatment. Forced aeration accelerated the maturing process, but could not improve the quality of the end product. Compared with continuous aeration, intermittent aeration could increase the O2 supply efficiency and reduced the total GHG emission by 17.8%, and this reduction increased to 47.4% when composting was ended after 36 days.展开更多
With increasing demands for clean and sustainable energy, the advantages of high power density, high efficiency, and long life expectancy have made supercapacitors one of the major emerging devices for electrochemical...With increasing demands for clean and sustainable energy, the advantages of high power density, high efficiency, and long life expectancy have made supercapacitors one of the major emerging devices for electrochemical energy storage and power supply. However, one of the key challenges for SCs is their limited energy density, which has hindered their wider application in the field of energy storage. Despite significant progress has been achieved in the fabrication of high-energy density positive electrodes materials, negative electrode materials with high capacitance and a wide potential window are relatively less explored. In this review, we introduced some new negative electrode materials except for common carbon-based materials and what's more, based on our team's work recently, we put forward some new strategies to solve their inherent shortcoming as electrode material for SCs.展开更多
Although the combination of electrochemistry and homogeneous catalysis has proven to be a powerful strategy for achieving a diverse array of novel transformations,some challenges such as controlling the diffusion of c...Although the combination of electrochemistry and homogeneous catalysis has proven to be a powerful strategy for achieving a diverse array of novel transformations,some challenges such as controlling the diffusion of catalyst-related species and the instability of catalysts at electrodes remain to be overcome.Herein,we review recent advances in electrochemical homogeneous catalysis,focusing on electrochemical noble-transition-metal catalysis,photoelectrochemical catalysis,and electrochemical enantioselective catalysis.The topics discussed include:(1)how the noblemetal catalystworks in the presence of cathodic hydrogen evolution,(2)how the photocatalyst gets enhanced redox property,and(3)how the enantioselectivity is regulated in a catalytic electrochemical reaction.展开更多
Lithium-ion batteries have emerged as the best portable energy storage device for the consumer electronics market. Recent progress in the development of lithium- ion batteries has been achieved by the use of selected ...Lithium-ion batteries have emerged as the best portable energy storage device for the consumer electronics market. Recent progress in the development of lithium- ion batteries has been achieved by the use of selected anode materials, which have driven improvements in performance in terms of capadty, cyclic stability, and rate capability. In this regard, research focusing on the design and electrochemical performance of full cell lithium-ion batteries, utilizing newly developed anode materials, has been widely reported, and great strides in development have been made. Nanostructured anode materials have contributed largely to the development of full cell lithium-ion batteries. With this in mind, we summarize the impact of nanostructured anode materials in the performance of coin cell full lithium-ion batteries. This review also discusses the challenges and prospects of research into full cell lithium-ion batteries.展开更多
The structure of the boundary layer affects the evolution of ozone(O3), and research into this structure will provide important insights for understanding photochemical pollution.In this study, we conducted a one-mont...The structure of the boundary layer affects the evolution of ozone(O3), and research into this structure will provide important insights for understanding photochemical pollution.In this study, we conducted a one-month observation(from June 15 to July 14, 2016) of the boundary layer meteorological factors as well as O3 and its precursors in Luancheng County,Shijiazhuang(37°53′N, 114°38′E). Our research showed that photochemical pollution in Shijiazhuang is serious, and the mean hourly maximum and mean 8-hr maximum O3 concentrations are 97.9 ± 26.1 and 84.4 ± 22.4 ppbV, respectively. Meteorological factors play a significant role in the formation of O3. High temperatures and southeasterly winds lead to elevated O3 values, and at moderate relative humidity(40%–50%) and medium boundary layer heights(1200–1500 m), O3 production sensitivity occurred in the transitional region between volatile organic compounds(VOC) and nitrogen oxides(NOx) limitations,and the O3 concentration was the highest. The vertical profiles of O3 were also measured by a tethered balloon. The results showed that a large amount of O3 was stored in the residual layer, and the concentration was positively correlated with the O3 concentration measured the previous day. During the daytime of the following day, the contribution of O3 stored in the residual layer to the boundary layer reached 27%± 7% on average.展开更多
Self-healing superhydrophobic polyvinylidene fluoride/Fe3O4@polypyrrole （F- PVDF/FeBO4@PPyx） fibers with core-sheath structure were successfully fabricated by electrospinning of a PVDF/Fe3O4 mixture and in situ chem...Self-healing superhydrophobic polyvinylidene fluoride/Fe3O4@polypyrrole （F- PVDF/FeBO4@PPyx） fibers with core-sheath structure were successfully fabricated by electrospinning of a PVDF/Fe3O4 mixture and in situ chemical oxidative polymerization of pyrrole, followed by chemical vapor deposition with fluoroalkyl silane. The F-PVDF/Fe3O4@PPy0.075 fiber film produces a superhydrophobic surface with self-healing behavior, which can repetitively and automatically restore superhydrophobicity when the surface is chemically damaged. Moreover, the maximum refection loss （Ru） of the F-PVDF/Fe304@PPy0.075 fiber film reaches -21.5 dB at 16.8 GHz and the RL below -10 dB is in the frequency range of 10.6-16.5 GHz with a thickness of 2.5 mm. The microwave absorption performance is attributed to the synergetic effect between dielectric loss and magnetic loss originating from PPy, PVDF and Fe3O4. As a consequence, preparing such F-PVDF/Fe3O4@PPyx fibers in this manner provides a simple and effective route to develop multi-functional microwave absorbing materials for practical applications.展开更多
An intensive and persistent regional ozone pollution event occurred over eastern China from 25 June to 5 July 2017.73 out of 96 selected cities,most located in the Beijing-TianjinHebei and the surrounding area(BTHS),s...An intensive and persistent regional ozone pollution event occurred over eastern China from 25 June to 5 July 2017.73 out of 96 selected cities,most located in the Beijing-TianjinHebei and the surrounding area(BTHS),suffered severe ozone pollution.A north-south contrast ozone distribution,with higher ozone(199±33μg/m3)in the BTHS and lower ozone(118±25μg/m^3)in the Yangtze River Delta(YRD),was found to be dominated by the position of the West Pacific Subtropical High(WPSH)and mid-high latitude wave activities.In the BTHS,the positive anomalies of geopotential height at 500 hPa and temperature at the surface indicated favorable meteorological conditions for local ozone formation.Prevailing northwesterly winds in the mid-high troposphere and warm advection induced by weak southerly winds in the low troposphere resulted in low-moderate relative humidity(RH),less total cloud cover(TGC),strong solar radiation and high temperatures.Moreover,southerly winds prevailing over the BTHS aggravated the pollution due to regional transportation of O3 and its precursors.On one hand,the deep sinking motion and inversion layer suppressed the dispersion of pollutants.On the other hand,O3-rich air in the upper layer was maintained at night due to temperature inversion,which facilitated O3 vertical transport to the surface in the next-day morning due to elevated convection.Generally,temperature,UV radiation,and RH showed good correlations with O3 in the BTHS,with rates of 8.51(μg/m^3)/℃(within the temperature range of 20-38℃),59.54(μg/m^3)/(MJ/m^2)and-1.93(μg/m^3)/%,respectively.展开更多
Aging is characterized by a progressive deterioration of physiological integrity,leading to impaired functional ability and ultimately increased susceptibility to death.It is a major risk factor for chronic human dise...Aging is characterized by a progressive deterioration of physiological integrity,leading to impaired functional ability and ultimately increased susceptibility to death.It is a major risk factor for chronic human diseases,including cardiovascular disease,diabetes,neurological degeneration,and cancer.Therefore,the growing emphasis on “healthy aging” raises a series of important questions in life and social sciences.In recent years,there has been unprecedented progress in aging research,particularly the discovery that the rate of aging is at least partly controlled by evolutionarily conserved genetic pathways and biological processes.In an attempt to bring full-fledged understanding to both the aging process and age-associated diseases,we review the descriptive,conceptual,and interventive aspects of the landscape of aging composed of a number of layers at the cellular,tissue,organ,organ system,and organismal levels.展开更多
Aims spatial distribution patterns of species reflect not only the ecological processes but also the habitat features that are related to species distribution.in karst topography,species distribution patterns provide ...Aims spatial distribution patterns of species reflect not only the ecological processes but also the habitat features that are related to species distribution.in karst topography,species distribution patterns provide more specific information about their environments.The objectives of this study are as follows:(i)to analyse and explain the spatial distribution patterns of conspecific trees in an old-growth subtropical karst forest;(ii)to investigate pattern changes at different spatial scales;(iii)to test the spatial pattern similarity(or dissimilarity)between trees at different abundances,diameter at breast height classes,canopy layers and different functional groups(shade tolerance and seed dispersal mode);(iv)to examine whether habitat heterogeneity has an important effect on the species spatial distribution.Methods The spatial distributions of woody species with≥20 individuals in a 1-ha subtropical karst forest plot at maolan in southwestern China were quantified using the relative neighbourhood densityΩbased on the average density of conspecific species in a circular neigh-bourhood around each species.Important Findingsaggregated distribution is the dominant pattern in the karst forest,but the ratio of aggregated species in total species number decreases with an increase in spatial scale.less abundant species are more aggregated than most abundant species.aggregation is weaker in larger diameter classes,which is consistent with the prediction of self-thinning.seed dispersal mode influences spatial patterns,with species dispersed by animals being less aggregated than those dispersed by wind and gravity.other species functional traits(e.g.shade tolerance)also influence the species spatial distributions.moreover,differences among species habitat associations,e.g.with rocky outcrops,play a significant role in species spatial distributions.These results indicate that habitat heterogeneity,seed dispersal limitation and self-thinning primarily contribute to the species spatial distributions in this subtropical k展开更多
With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel(CA) with highly enhanced thermal conductivity(TC) in vertical...With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel(CA) with highly enhanced thermal conductivity(TC) in vertical planes was successfully obtained by constructing a vertically aligned silicon carbide nanowires(SiC NWs)/boron nitride(BN) network via the ice template-assisted strategy. The unique network structure of SiC NWs connected to BN ensures that the TC of the composite in the vertical direction reaches 2.21 W m^(-1) K^(-1) at a low hybrid filler loading of 16.69 wt%, which was increased by 890% compared to pure epoxy(EP). In addition, relying on unique porous network structure of CA, EP-based composite also showed higher TC than other comparative samples in the horizontal direction. Meanwhile, the composite exhibits good electrically insulating with a volume electrical resistivity about 2.35 × 10^(11) Ω cm and displays excellent electromagnetic wave absorption performance with a minimum reflection loss of-21.5 dB and a wide effective absorption bandwidth(<-10 dB) from 8.8 to 11.6 GHz. Therefore, this work provides a new strategy for manufacturing polymer-based composites with excellent multifunctional performances in microelectronic packaging applications.展开更多
基金Project supported by the National Natural Science Founding of China(No.20347003,40121303)the Research Grants Council of Hong Kong(No.PolyU5038/01E,PolyU5145/03E)the Area of Strategic Development on Atmospheric and Urban Air Pollution of The Hong Kong Polytechnic University(No.A516,A510).
文摘PM2.5 and PM10 samples were collected at four major cities in the Pearl River Delta （PRD）, South China, during winter and summer in 2002. Six water-soluble ions, Na^＋, NH4＋, K^＋, Cl^-, NO3^- and SO4^2- were measured using ion chromatography. On average, ionic species accounted for 53.3% and 40.5% for PM2.5 and PM10, respectively in winter and 39.4% and 35.2%, respectively in summer. Secondary ions such as sulfate, nitrate and ammonium accounted for the major part of the total ionic species. Sulfate was the most abundant species followed by nitrate. Overall, a regional pollution tendency was shown that there were higher concentrations of sulfate, nitrate and ammonium in Guangzhou City than those in the other PRD cities. Significant seasonal variations were also observed with higher levels of species in winter but lower in summer. The Asian monsoon system was favorable for removal and diffusion of air pollutants in PRD in summer while highly loading of local industrial emissions tended to deteriorate the air quality as well. NO3^-/SO4^2- ratio indicated that mobile sources have considerably contribution to the urban aerosol, and stationary sources should not be neglected. Besides the primary emissions, complex atmospheric reactions under favorable weather conditions should be paid more attention for the control of primary emission in the PRD region.
基金supported by the National Natural Science Foundation of China (No. 21507130)the Open Project Program of Beijing National Laboratory for Molecular Sciences (No. 20140142)+3 种基金the Open Project Program of Chongqing Key Laboratory of Environmental Materials and Remediation Technology from Chongqing University of Arts and Sciences (No. CEK1405)the Open Project Program of Jiangsu Key Laboratory of Vehicle Emissions Control (No. OVEC001)the Open Project Program of Chongqing Key Laboratory of Catalysis and Functional Organic Molecules from Chongqing Technology and Business University (1456029)the Chongqing Science & Technology Commission (Nos. cstc2016jcyj A0070, cstc2014pt-gc20002, cstckjcxljrc13)~~
文摘This work examines the influence of preparation methods on the physicochemical properties and catalytic performance of MnOx‐CeO2 catalysts for selective catalytic reduction of NO by NH3 (NH3‐SCR) at low temperature. Five different methods, namely, mechanical mixing, impregnation,hydrothermal treatment, co‐precipitation, and a sol‐gel technique, were used to synthesizeMnOx‐CeO2 catalysts. The catalysts were characterized in detail, and an NH3‐SCR model reaction waschosen to evaluate the catalytic performance. The results showed that the preparation methodsaffected the catalytic performance in the order: hydrothermal treatment > sol‐gel > co‐precipitation> impregnation > mechanical mixing. This order correlated with the surface Ce3+ and Mn4+ content,oxygen vacancies and surface adsorbed oxygen species concentration, and the amount of acidic sitesand acidic strength. This trend is related to redox interactions between MnOx and CeO2. The catalystformed by a hydrothermal treatment exhibited excellent physicochemical properties, optimal catalyticperformance, and good H2O resistance in NH3‐SCR reaction. This was attributed to incorporationof Mnn+ into the CeO2 lattice to form a uniform ceria‐based solid solution (containing Mn‐O‐Cestructures). Strengthening of the electronic interactions between MnOx and CeO2, driven by thehigh‐temperature and high‐pressure conditions during the hydrothermal treatment also improved the catalyst characteristics. Thus, the hydrothermal treatment method is an efficient and environment‐friendly route to synthesizing low‐temperature denitrification (deNOx) catalysts.
基金supported by the Ministry of Science and Technology National Key Research and Development Program (Grant No. 2017YFC0210000)the Fundamental Heavy Pollution Cause and Governance Research Project (Grant No. DQGG0101)the Beijing Municipal Science and Technology Commission Capital Blue Sky Action and Cultivation Project (Grant No. Z181100005418014)
文摘Accurate determination of the atmospheric particulate matter mass concentration and chemical composition is helpful in exploring the causes and sources of atmospheric enthalpy pollution and in evaluating the rationality of environmental air quality control strategies.Based on the sampling and chemical composition data of PM2.5 in different key regions of China in the CARE-China observation network,this research analyzes the environmental air quality data released by the China National Environmental Monitoring Centre during the studied period to determine the changes in the particulate matter mass concentration in key regions and the evolution of the corresponding chemical compositions during the implementation of the Action Plan for Prevention and Control of Air Pollution from 2013-2017.The results show the following.(1)The particulate matter mass concentration in China showed a significant downward trend;however,the PM2.5 annual mass concentration in 64%of cities exceeds the New Chinese Ambient Air Quality Standard(CAAQS)GradeⅡ(GB3095-2012).The region to the east of the Taihang Mountains,the Fenhe and Weihe River Plain and the Urumqi-Changji regions in Xinjiang,all have PM2.5 concentration loading that is still high,and heavy haze pollution occurred frequently in the autumn and winter.(2)During the heavy pollution in the autumn and winter,the concentrations of sulfate and organic components decreased significantly.The mean SO42-concentration in PM2.5 decreased by 76%,12%,81%and 38%in Beijing-Tianjin-Hebei(BTH),the Pearl River Delta(PRD),the Sichuan-Chongqing region(SC)and the Fenhe and Weihe River Plain,respectively.The mean organic matter(OM)concentration decreased by 70%,44%,48%and 31%,respectively,and the mean concentration of NH4+decreased by 68%,1.6%,38%and 25%,respectively.The mean elemental carbon(EC)concentration decreased by 84%and 20%in BTH and SC,respectively,and it increased by 61%and 11%in the PRD and Fenhe and Weihe River Plain,respectively.The mean concentration of mineral and unresolved chemica
基金the National Basic Research Program of China (973Program, 2006CB500401).
文摘Continuous observation data collected over the whole year of 2004 on a cropland surtace m Tongyu, a senti-arid area of northeastern China （44°25＇N, 122°52＇E）, have been used to investigate the variations of surface albedo and soil thermal parameters, including heat capacity, thermal conductivity and thermal diffusivity, and their relationships to soil moisture. The diurnal variation of surface albedo appears as a U shape curve on sunny days. Surface albedo decreases with the increase of solar elevation angle, and it tends to be a constant when solar elevation angle is larger than 40°. So the daily average surface albedo was computed using the data when solar elevation angle is larger than 40° Mean daily surface albedo is found to decrease with the increase of soil moisture, showing an exponential dependence on soil moisture. The variations of soil heat capacity are small during Julian days 90 300. Compared with the heat capacity, soil thermal conductivity has very gentle variations during this period, but the soil thermal diffusivity has wide variations during the same period. The soil thermal conductivity is found to increase as a power function of soil moisture. The soil thermal diffusivity increases firstly and then decreases with the increase of soil moisture.
基金The work of A.Jacobsen,C.Evelo,M.Thompson,R.Cornet,R.Kaliyaperuma and M.Roos is supported by funding from the European Union’s Horizon 2020 research and innovation program under the EJP RD COFUND-EJP N°825575.The work of A.Jacobsen,C.Evelo,C.Goble,M.Thompson,N.Juty,R.Hooft,M.Roos,S-A.Sansone,P.McQuilton,P.Rocca-Serra and D.Batista is supported by funding from ELIXIR EXCELERATE,H2020 grant agreement number 676559.R.Hooft was further funded by NL NWO NRGWI.obrug.2018.009.N.Juty and C.Goble were funded by CORBEL(H2020 grant agreement 654248)N.Juty,C.Goble,S-A.Sansone,P.McQuilton,P.Rocca-Serra and D.Batista were funded by FAIRplus(IMI grant agreement 802750)+12 种基金N.Juty,C.Goble,M.Thompson,M.Roos,S-A.Sansone,P.McQuilton,P.Rocca-Serra and D.Batista were funded by EOSClife H2020-EU(grant agreement number 824087)C.Goble was funded by DMMCore(BBSRC BB/M013189/)M.Thompson,M.Roos received funding from NWO(VWData 400.17.605)S-A.Sansone,P.McQuilton,P.Rocca-Serra and D.Batista have been funded by grants awarded to S-A.Sansone from the UK BBSRC and Research Councils(BB/L024101/1,BB/L005069/1)EU(H2020-EU 634107H2020-EU 654241,IMI(IMPRiND 116060)NIH Data Common Fund,and from the Wellcome Trust(ISA-InterMine 212930/Z/18/ZFAIRsharing 208381/A/17/Z)The work of A.Waagmeester has been funded by grant award number GM089820 from the National Institutes of Health.M.Kersloot was funded by the European Regional Development Fund(KVW-00163).The work of N.Meyers was funded by the National Science Foundation(OAC 1839030)The work of M.D.Wilkinson is funded by Isaac Peral/Marie Curie cofund with the Universidad Politecnica de Madrid and the Ministerio de Economia y Competitividad grant number TIN2014-55993-RMThe work of B.Magagna,E.Schultes,L.da Silva Santos and K.Jeffery is funded by the H2020-EU 824068The work of B.Magagna,E.Schultes and L.da Silva Santos is funded by the GO FAIR ISCO grant of the Dutch Ministry of Science and CultureThe work of G.Guizzardi is supported by the OCEAN Project(FUB).M.Courtot received funding from the I
文摘The FAIR principles have been widely cited,endorsed and adopted by a broad range of stakeholders since their publication in 2016.By intention,the 15 FAIR guiding principles do not dictate specific technological implementations,but provide guidance for improving Findability,Accessibility,Interoperability and Reusability of digital resources.This has likely contributed to the broad adoption of the FAIR principles,because individual stakeholder communities can implement their own FAIR solutions.However,it has also resulted in inconsistent interpretations that carry the risk of leading to incompatible implementations.Thus,while the FAIR principles are formulated on a high level and may be interpreted and implemented in different ways,for true interoperability we need to support convergence in implementation choices that are widely accessible and(re)-usable.We introduce the concept of FAIR implementation considerations to assist accelerated global participation and convergence towards accessible,robust,widespread and consistent FAIR implementations.Any self-identified stakeholder community may either choose to reuse solutions from existing implementations,or when they spot a gap,accept the challenge to create the needed solution,which,ideally,can be used again by other communities in the future.Here,we provide interpretations and implementation considerations(choices and challenges)for each FAIR principle.
基金supported by the National Natural Science Foundation of China(No.40971177)the National Key Technology R&D Program(No.2012BAD14B01,2012BAD14B03)+1 种基金the Sino-German Cooperation Project of Recycling of Organic Residues from Agricultural and Municipal Residues in China(No.BMBF,FKZ0330847)the Chinese Universities Scientific Fund
文摘A laboratory scale experiment of composting in a forced aeration system using pig manure with cornstalks was carried out to investigate the effects of both phosphogypsum and dicyandiamide （DCD, C2 H4 N4 ） as additives on gaseous emissions and compost quality. Besides a control, there were three amended treatments with different amounts of additives. The results indicated that the phosphogypsum addition at the rate of 10% of mixture dry weight decreased NH3 and CH4 emissions significantly during composting. The addition of DCD at the rate of 0.2% of mixture dry weight together with 10% of phosphogypsum further reduced the N20 emission by affecting the nitrification process. Reducing the phosphogypsum addition to 5% in the presence of 0.2% DCD moderately increased the NH3 emissions but not N20 emission. The additives increased the ammonium content and electrical conductivity significantly in the final compost. No adverse effect on organic matter degradation or the germination index of the compost was found in the amended treatments. It was recommended that phosphogypsum and DCD could be used in composting for the purpose of reducing NH3 , CH4 and N20 emissions.0ptimal conditions and dose of DCD additive during composting should be determined with different materials and composting systems in further study.
基金Supported by the National Key Project of the Ministry of Science and Technology of China(2016YFC0203306)Basic Scientific Research Project of the Chinese Academy of Meteorological Sciences(2016Z001)
文摘Based on observations of urban mass concentration of fine particulate matter smaller than 2.5 μm in diameter （PM2.5）, ground meteorological data, vertical measurements of winds, temperature, and relative humidity （RH）, and ECMWF reanalysis data, the major changes in the vertical structures of meteorological factors in the boundary layer （BL） during the heavy aerosol pollution episodes （HPEs） that occurred in winter 2016 in the urban Beijing area were analyzed. The HPEs are divided into two stages： the transport of pollutants under prevailing southerly winds, known as the transport stage （TS）, and the PM2.5 explosive growth and pollution accumulation period characterized by a temperature inversion with low winds and high RH in the lower BL, known as the cumulative stage （CS）. During the TS, a surface high lies south of Beijing, and pollutants are transported northwards. During the CS, a stable BL forms and is characterized by weak winds, temperature inversion, and moisture accumulation. Stable atmospheric stratifica- tion featured with light/calm winds and accumulated moisture （RH 〉 80%） below 250 m at the beginning of the CS is closely associated with the inversion, which is strengthened by the considerable decrease in near-surface air temperat- ure due to the interaction between aerosols and radiation after the aerosol pollution occurs. A significant increase in the PLAM （Parameter Linking Aerosol Pollution and Meteorological Elements） index is found, which is linearly re- lated to PM mass change. During the first 10 h of the CS, the more stable BL contributes approximately 84% of the explosive growth of PM2.5 mass. Additional accumulated near-surface moisture caused by the ground temperature de- crease, weak turbulent diffusion, low BL height, and inhibited vertical mixing of water vapor is conducive to the sec- ondary aerosol formation through chemical reactions, including liquid phase and heterogeneous reactions, which fur- ther increases the PM2.5 concentration levels. Th
基金supported by the Science Challenge Project (TZ2016004)the National Natural Science Foundation of China (21836001, 21876048)
文摘With the development of nuclear energy, large amounts of radionuclides are inevitably released into the natural environment. It is necessary to eliminate radionuclides from wastewater for the protection of environment. Nanomaterials have been considered as the potential candidates for the effective and selective removal of radionuclides from aqueous solutions under complicated conditions because of their high specific surface area, large amounts of binding sites, abundant functional groups, pore-size controllable and easily surface modification. This review mainly summarized the recent studies for the synthesis, fabrication and surface modification of novel nanomaterials and their applications in the efficient elimination and solidification of radionuclides,and discussed the interaction mechanisms from batch experiments, spectroscopy analysis and theoretical calculations. The sorption capacities with other materials, advantages and disadvantages of different nanomaterials are compared, and at last the perspective of the novel nanomaterials is summarized.
基金supported by the LAC/CMA(No.2017B02)the National Natural Science Foundation of China(No.41330422)the Special Fund for Meteorological Research in the Public Interest(No.GYHY201206015)
文摘We investigated the seasonal and spatial ozone variations in China by using three-year surface ozone observation data from the six Chinese Global Atmosphere Watch(GAW)stations and tropospheric column ozone data from satellite retrieval over the period2010–2012. It is shown that the seasonal ozone variations at these GAW stations are rather different, particularly between the western and eastern locations. Compared with western China, eastern China has lower background ozone levels. However, the Asian summer monsoon(ASM) can transport photochemical pollutants from the southern to the northern areas in eastern China, leading to a northward gradual enhancement of background ozone levels at the eastern GAW stations. Over China, the tropospheric column ozone densities peak during spring and summer in the areas that are directly and/or indirectly affected by the ASM, and the peak time lags from the south to the north in eastern China. We also investigated the regional representativeness of seasonal variations of ozone at the six Chinese GAW stations using the yearly maximum tropospheric column month as indicator.The results show that the seasonal variation characteristics of ozone revealed by the Chinese GAW stations are typical, with each station having a considerable large surrounding area with the ozone maximum occurring at the same month. Ozone variations at the GAW stations are influenced by many complex factors and their regional representativeness needs to be investigated further in a broader sense.
基金supported by the National Natural Science Foundation of China (No. 41201282)part of the Chinese National Science and Technology Support Program (2012BAD14B01/06/18)Leshan Normal University Foundation Z1159
文摘The aim of this study was to uncover ways to mitigate greenhouse gas（GHG） emissions and reduce energy consumption during the composting process. We assessed the effects of different aeration rates（0, 0.18, 0.36, and 0.54 L/（kg dry matter（dm）·min）） and methods（continuous and intermittent） on GHG emissions. Pig feces and corn stalks were mixed at a ratio of 7：1. The composting process lasted for 10 weeks, and the compost was turned approximately every 2 weeks. Results showed that both aeration rate and method significantly affected GHG emissions. Higher aeration rates increased NH3 and N2O losses,but reduced CH4 emissions. The exception is that the CH4 emission of the passive aeration treatment was lower than that of the low aeration rate treatment. Without forced aeration,the CH4 diffusion rates in the center of the piles were very low and part of the CH4 was oxidized in the surface layer. Intermittent aeration reduced NH3 and CH4 losses, but significantly increased N2 O production during the maturing periods. Intermittent aeration increased the nitrification/denitrification alternation and thus enhanced the N2 O production. Forced aeration treatments had higher GHG emission rates than the passive aeration treatment. Forced aeration accelerated the maturing process, but could not improve the quality of the end product. Compared with continuous aeration, intermittent aeration could increase the O2 supply efficiency and reduced the total GHG emission by 17.8%, and this reduction increased to 47.4% when composting was ended after 36 days.
基金supported by the National Natural Science Foundation of China(Grant Nos.51173212&21273290)the National Basic Research Program of China("973"Project)(Grant No.2015CB932304)+4 种基金the Natural Science Foundations of Guangdong Province(Grant Nos.S2013020012833&S2013030013474)Fundamental Research Fund for the Central Universities(Grant No.13lgpy51)SRF for ROCS,SEM(Grant No.[2012]1707)the Project of High Level Talents in Higher School of Guangdong Province,and Open-End Fund of Key Laboratory of Functional Inorganic Material Chemistry(Heilongjiang University)Ministry of Education,and the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120171110043)
文摘With increasing demands for clean and sustainable energy, the advantages of high power density, high efficiency, and long life expectancy have made supercapacitors one of the major emerging devices for electrochemical energy storage and power supply. However, one of the key challenges for SCs is their limited energy density, which has hindered their wider application in the field of energy storage. Despite significant progress has been achieved in the fabrication of high-energy density positive electrodes materials, negative electrode materials with high capacitance and a wide potential window are relatively less explored. In this review, we introduced some new negative electrode materials except for common carbon-based materials and what's more, based on our team's work recently, we put forward some new strategies to solve their inherent shortcoming as electrode material for SCs.
基金supported by the National Science Foundation of China(nos.22071105 and 22031008)the Qinglan Project of Jiangsu Education Department.
文摘Although the combination of electrochemistry and homogeneous catalysis has proven to be a powerful strategy for achieving a diverse array of novel transformations,some challenges such as controlling the diffusion of catalyst-related species and the instability of catalysts at electrodes remain to be overcome.Herein,we review recent advances in electrochemical homogeneous catalysis,focusing on electrochemical noble-transition-metal catalysis,photoelectrochemical catalysis,and electrochemical enantioselective catalysis.The topics discussed include:(1)how the noblemetal catalystworks in the presence of cathodic hydrogen evolution,(2)how the photocatalyst gets enhanced redox property,and(3)how the enantioselectivity is regulated in a catalytic electrochemical reaction.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21273290 and 21476271）, the Natural Science Foundation of Guangdong Province （Nos. S2013030013474 and 2014KTSCX004） and the Science and Technology Plan Project of Guangdong Province （Nos. 2014B101123002, 2014B050505001 and 2015B010118002）. We thank the Middle School Student Talent Plan.
文摘Lithium-ion batteries have emerged as the best portable energy storage device for the consumer electronics market. Recent progress in the development of lithium- ion batteries has been achieved by the use of selected anode materials, which have driven improvements in performance in terms of capadty, cyclic stability, and rate capability. In this regard, research focusing on the design and electrochemical performance of full cell lithium-ion batteries, utilizing newly developed anode materials, has been widely reported, and great strides in development have been made. Nanostructured anode materials have contributed largely to the development of full cell lithium-ion batteries. With this in mind, we summarize the impact of nanostructured anode materials in the performance of coin cell full lithium-ion batteries. This review also discusses the challenges and prospects of research into full cell lithium-ion batteries.
基金supported by the National Key R&D Program of China(Nos.2017YFC0210000 and 2016YFC0203100)State Key Laboratory of Atmospheric Chemistry,Chinese Meteorological Administration(LAC/CMA)(No.2017A01)+4 种基金the Young Talent Project of the Center for Excellence in Regional Atmospheric Environment,Chinese Academy of Sciences(CAS)(No.CERAE201802)the National Natural Science Foundation of China(Nos.41705113,41877312 and 41675124)the National research program for key issues in air pollution control(No.DQGG0101)Beijing Major Science and Technology Project(No.Z181100005418014)Postgraduate Research and Practice Innovation Program of Jiangsu Province(No.SJCX18_0327)
文摘The structure of the boundary layer affects the evolution of ozone(O3), and research into this structure will provide important insights for understanding photochemical pollution.In this study, we conducted a one-month observation(from June 15 to July 14, 2016) of the boundary layer meteorological factors as well as O3 and its precursors in Luancheng County,Shijiazhuang(37°53′N, 114°38′E). Our research showed that photochemical pollution in Shijiazhuang is serious, and the mean hourly maximum and mean 8-hr maximum O3 concentrations are 97.9 ± 26.1 and 84.4 ± 22.4 ppbV, respectively. Meteorological factors play a significant role in the formation of O3. High temperatures and southeasterly winds lead to elevated O3 values, and at moderate relative humidity(40%–50%) and medium boundary layer heights(1200–1500 m), O3 production sensitivity occurred in the transitional region between volatile organic compounds(VOC) and nitrogen oxides(NOx) limitations,and the O3 concentration was the highest. The vertical profiles of O3 were also measured by a tethered balloon. The results showed that a large amount of O3 was stored in the residual layer, and the concentration was positively correlated with the O3 concentration measured the previous day. During the daytime of the following day, the contribution of O3 stored in the residual layer to the boundary layer reached 27%± 7% on average.
基金The work is supported by the National Natural Sdence Foundation of China （Nos. 51273008, 51473008, and 21103006）, Beijing Natural Science Foundation （No. 2132030） and the National Basic Research Program of China （No. 2012CB933200）.
文摘Self-healing superhydrophobic polyvinylidene fluoride/Fe3O4@polypyrrole （F- PVDF/FeBO4@PPyx） fibers with core-sheath structure were successfully fabricated by electrospinning of a PVDF/Fe3O4 mixture and in situ chemical oxidative polymerization of pyrrole, followed by chemical vapor deposition with fluoroalkyl silane. The F-PVDF/Fe3O4@PPy0.075 fiber film produces a superhydrophobic surface with self-healing behavior, which can repetitively and automatically restore superhydrophobicity when the surface is chemically damaged. Moreover, the maximum refection loss （Ru） of the F-PVDF/Fe304@PPy0.075 fiber film reaches -21.5 dB at 16.8 GHz and the RL below -10 dB is in the frequency range of 10.6-16.5 GHz with a thickness of 2.5 mm. The microwave absorption performance is attributed to the synergetic effect between dielectric loss and magnetic loss originating from PPy, PVDF and Fe3O4. As a consequence, preparing such F-PVDF/Fe3O4@PPyx fibers in this manner provides a simple and effective route to develop multi-functional microwave absorbing materials for practical applications.
基金supported by a grant from the National Key R&D Plan(Quantitative Relationship and Regulation Principle between Regional Oxidation Capacity of Atmospheric and Air Quality 2017YFC0210003)the National Natural Science Foundation of China(No.41505133&41775162)+1 种基金the National Research Program for Key Issues in Air Pollution Control(DQGG0101)the Beijing Major Science and Technology Project 510(No.Z181100005418014)。
文摘An intensive and persistent regional ozone pollution event occurred over eastern China from 25 June to 5 July 2017.73 out of 96 selected cities,most located in the Beijing-TianjinHebei and the surrounding area(BTHS),suffered severe ozone pollution.A north-south contrast ozone distribution,with higher ozone(199±33μg/m3)in the BTHS and lower ozone(118±25μg/m^3)in the Yangtze River Delta(YRD),was found to be dominated by the position of the West Pacific Subtropical High(WPSH)and mid-high latitude wave activities.In the BTHS,the positive anomalies of geopotential height at 500 hPa and temperature at the surface indicated favorable meteorological conditions for local ozone formation.Prevailing northwesterly winds in the mid-high troposphere and warm advection induced by weak southerly winds in the low troposphere resulted in low-moderate relative humidity(RH),less total cloud cover(TGC),strong solar radiation and high temperatures.Moreover,southerly winds prevailing over the BTHS aggravated the pollution due to regional transportation of O3 and its precursors.On one hand,the deep sinking motion and inversion layer suppressed the dispersion of pollutants.On the other hand,O3-rich air in the upper layer was maintained at night due to temperature inversion,which facilitated O3 vertical transport to the surface in the next-day morning due to elevated convection.Generally,temperature,UV radiation,and RH showed good correlations with O3 in the BTHS,with rates of 8.51(μg/m^3)/℃(within the temperature range of 20-38℃),59.54(μg/m^3)/(MJ/m^2)and-1.93(μg/m^3)/%,respectively.
基金supported by the National Natural Science Foundation of China(31871380,32000500,32070730,32170756,32170804,81330008,81671377,81725010,81725010,81872874,81921006,81922027,81971312,81991512,82030041,82103167,82122024,82125009,82125011,82130044,91749126,91949101,91949207,92049302)the National Key Research and Development Program of China(2017YFA0506400,2018YFA0800200,2018YFA0800700,2018YFA0900200,2018YFC2000100,2018YFC2000400,2018YFE-0203700,20192ACB70002,2019YFA0802202,2020YFA0113400,2020YFA0803401,2020YFA0804000,2020YFC2002800,2020YFC-2002900,2021ZD0202401)+11 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA16010100,XDA16010603,XDA16020400,XDB29020000,XDB39000000,XDB39000000,XDB39030300)the China Association for Science and Technology(2021QNRC001)the Beijing Municipal Science and Technology Commission(Z200022)the Natural Science Foundation of Shanghai(21JC1406400)the Key Programs of the Jiangxi ProvinceChina(20192ACB70002)the“Shu Guang”Project supported by the Shanghai Municipal Education Commission and Shanghai Education Development Foundation(19SG18)the Shanghai Sailing Program(22YF1434300)the Research Project of Joint Laboratory of University of Science and Technology of China and Anhui Mental Health Center(2019LH03)the Fundamental Research Funds for the Central Universities(WK2070210004)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(YESS20210002)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2022083)。
文摘Aging is characterized by a progressive deterioration of physiological integrity,leading to impaired functional ability and ultimately increased susceptibility to death.It is a major risk factor for chronic human diseases,including cardiovascular disease,diabetes,neurological degeneration,and cancer.Therefore,the growing emphasis on “healthy aging” raises a series of important questions in life and social sciences.In recent years,there has been unprecedented progress in aging research,particularly the discovery that the rate of aging is at least partly controlled by evolutionarily conserved genetic pathways and biological processes.In an attempt to bring full-fledged understanding to both the aging process and age-associated diseases,we review the descriptive,conceptual,and interventive aspects of the landscape of aging composed of a number of layers at the cellular,tissue,organ,organ system,and organismal levels.
基金One Hundred Talents Program of the Chinese Academy of Sciences to J.N.National Basic Research Program(973)of the China Ministry of Science and Technology(2006CB403207).
文摘Aims spatial distribution patterns of species reflect not only the ecological processes but also the habitat features that are related to species distribution.in karst topography,species distribution patterns provide more specific information about their environments.The objectives of this study are as follows:(i)to analyse and explain the spatial distribution patterns of conspecific trees in an old-growth subtropical karst forest;(ii)to investigate pattern changes at different spatial scales;(iii)to test the spatial pattern similarity(or dissimilarity)between trees at different abundances,diameter at breast height classes,canopy layers and different functional groups(shade tolerance and seed dispersal mode);(iv)to examine whether habitat heterogeneity has an important effect on the species spatial distribution.Methods The spatial distributions of woody species with≥20 individuals in a 1-ha subtropical karst forest plot at maolan in southwestern China were quantified using the relative neighbourhood densityΩbased on the average density of conspecific species in a circular neigh-bourhood around each species.Important Findingsaggregated distribution is the dominant pattern in the karst forest,but the ratio of aggregated species in total species number decreases with an increase in spatial scale.less abundant species are more aggregated than most abundant species.aggregation is weaker in larger diameter classes,which is consistent with the prediction of self-thinning.seed dispersal mode influences spatial patterns,with species dispersed by animals being less aggregated than those dispersed by wind and gravity.other species functional traits(e.g.shade tolerance)also influence the species spatial distributions.moreover,differences among species habitat associations,e.g.with rocky outcrops,play a significant role in species spatial distributions.These results indicate that habitat heterogeneity,seed dispersal limitation and self-thinning primarily contribute to the species spatial distributions in this subtropical k
基金financial support from National Natural Science Foundation of China(21704096,51703217)the China Postdoctoral Science Foundation(Grant No.2019M662526)financial support from Taif University Researchers Supporting Project Number(TURSP-2020/135),Taif University,Taif,Saudi Arabia。
文摘With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel(CA) with highly enhanced thermal conductivity(TC) in vertical planes was successfully obtained by constructing a vertically aligned silicon carbide nanowires(SiC NWs)/boron nitride(BN) network via the ice template-assisted strategy. The unique network structure of SiC NWs connected to BN ensures that the TC of the composite in the vertical direction reaches 2.21 W m^(-1) K^(-1) at a low hybrid filler loading of 16.69 wt%, which was increased by 890% compared to pure epoxy(EP). In addition, relying on unique porous network structure of CA, EP-based composite also showed higher TC than other comparative samples in the horizontal direction. Meanwhile, the composite exhibits good electrically insulating with a volume electrical resistivity about 2.35 × 10^(11) Ω cm and displays excellent electromagnetic wave absorption performance with a minimum reflection loss of-21.5 dB and a wide effective absorption bandwidth(<-10 dB) from 8.8 to 11.6 GHz. Therefore, this work provides a new strategy for manufacturing polymer-based composites with excellent multifunctional performances in microelectronic packaging applications.
