Drought,as the most catastrophic abiotic stress,poses a significant threat to the growth and development of plants.Among the mechanisms employed by plants to cope with drought-induced stress,abscisic acid(ABA)which is...Drought,as the most catastrophic abiotic stress,poses a significant threat to the growth and development of plants.Among the mechanisms employed by plants to cope with drought-induced stress,abscisic acid(ABA)which is the sesquiterpene hormone,occupies a pivotal role.A hypothesis has emerged that the exogenous application of ABA can positively influence the terpenoid content of Lavandula angustifolia cv Hidcote essential oil(EO),thereby conferring enhanced resilience to drought stress.A randomized complete block design experiment was conducted with three replicationsandfour irrigation regimes,including I4[30%-40%of field capacity(FC)],I3(50%-60%FC),I2(70%-80%FC),andI1(90%-100%FC)as control.Application of ABAspraying included three concentrations,A3(30μmol·L^(-1)ABA),A2(15μmol·L^(-1)ABA),and A1 as control(distilled water).Results revealed that drought significantly affected all studied traits except for relative water content(RWC)and shoot dry mass.The ABA impact application on the observed traits was found to be dependent upon the level of drought to which the plants were exposed.Specifically,the highest levels of flavonoid content,total antioxidant activity,peroxidase(POX)activity,and EO percentage were observed under I4A2 conditions.Conversely,the highest levels of superoxide dismutase(SOD)and catalase(CAT)activity,and proline were recorded under I4A3 conditions,while the highest EO yield was obtained under I3A2 conditions.Analysis of the EO revealed that there were common indicative compounds across the varying levels of droughtandABAapplication,including linalool,camphor,borneol,bornyl formate,andcaryophyllene oxide.Theproduction pattern ofmonoterpene and sesquiterpene compounds demonstrated a distinct trend,with the highest concentration of monoterpene hydrocarbon compounds(average of 12.92%)being observed in the I2A3 treatment group,andthe highest concentration of oxygenatedmonoterpenecompounds(average of 64.76%)being recorded in the I1A1 group.Conversely,the most significant levels of sesquiterpene hydrocarboncompounds(14.98%)andoxygenated sesquiterpene compounds(10.46%)were observed in the I4A3 and I4A1 groups,respectively,showing the efficacy of monoterpenes and sesquiterpenes from the action of ABA under drought conditions.The observed results indicated that the concentration of oxygenated monoterpene compounds decreases with an increase in drought level.Conversely,the application of ABA at any given drought level appears to resulted in increased concentrations of oxygenated monoterpene compounds in the same conditions.It may be concluded that plants under high-stress drought conditions allocate more terpene precursors to the production of sesquiterpene hydrocarbon compounds,aided by ABA with the same properties.展开更多
Background As an indigenous livestock species on the Tibetan Plateau,Tibetan sheep exhibit remarkable adaptability to low temperatures and nutrient-scarce environments.During the cold season,Tibetan sheep are typicall...Background As an indigenous livestock species on the Tibetan Plateau,Tibetan sheep exhibit remarkable adaptability to low temperatures and nutrient-scarce environments.During the cold season,Tibetan sheep are typically managed under two feeding regimes:barn feeding(BF)and traditional grazing(TG).However,the molecular mechanisms underlying their adaptation to these distinct management strategies remain unclear.This study aimed to investigate the adaptive strategies of rumen function in Tibetan sheep to cold-season feeding regimes by integrating analyses of rumen morphology,microbiome,metabolome,and transcriptome.Twelve healthy Tibetan sheep with similar body weights were assigned into two groups(BF vs.TG).At the end of the experiment,rumen tissues were subjected to histological observation.Multi-omics techniques were employed to evaluate the effects of cold-season feeding regimes on rumen function in Tibetan sheep.Results The ruminal papilla height,width,and muscular thickness were significantly higher in BF group.The relative abundances of Actinobacteria and Succiniclasticum were significantly elevated in the rumen of BF group,whereas Rikenellaceae,Gracilibacteria,and Lachnospiraceae showed higher abundances in the TG group.Metabolomic analysis identified 19 differential metabolites between the two groups,including upregulated compounds in BF group(fumaric acid,maltose,L-phenylalanine,and L-alanine)and TG group(e.g.,phenylacetic acid,salicyluric acid and ferulic acid).These metabolites were predominantly enriched in phenylalanine metabolism,alanine,aspartate and glutamate metabolism,and phenylalanine,tyrosine and tryptophan biosynthesis pathways.Additionally,210 differentially expressed genes(DEGs)were identified in rumen epithelium:100 upregulated DEGs in the BF group were enriched in nutrient metabolism-related pathways(e.g.,fatty acid degradation and PPAR signaling pathway),while 110 upregulated DEGs in the TG group were associated with immune-related pathways(e.g.,p53 signaling pathway and glutathione metabolism).Conclusions Among these,we observed distinct rumen functional responses to different cold-season feeding regimes in Tibetan sheep and revealed energy allocation strategies mediated by host-microbe interactions.In the BF group,Tibetan sheep adopted a"metabolic efficiency-priority"strategy,driving rumen microbiota to maximize energy capture from high-nutrient diets to support host growth.In contrast,the TG group exhibited an"environmental adaptation-priority"strategy,where rumen microbiota prioritized cellulose degradation and anti-inflammatory functions,reallocating energy toward homeostasis maintenance at the expense of rumen development and growth performance.展开更多
Semiconductor electronic devices are prone to charge accumulation during production and transportation,which usually causes device breakdown.Ionizers are widely used for electrostatic elimination,and utilizing semicon...Semiconductor electronic devices are prone to charge accumulation during production and transportation,which usually causes device breakdown.Ionizers are widely used for electrostatic elimination,and utilizing semiconductor silicon for the discharge needle material in ionizers can effectively prevent metal contamination.To investigate the discharge characteristics of silicon needles and their mode modulation mechanism,this study has established an experimental platform for silicon needle-plate discharge under positive polarity voltage.Discharge pulse parameters and optical signals were measured at varying electrode spacings.The experimental results reveal that silicon needle discharge progresses through four regimes:the spontaneous streamer,the periodic streamer,the cluster streamer,and the glow discharge.Among these,the pulse amplitude is most uniform and stable in the periodic streamer regime.In addition,shorter-gap discharge exhibits higher pulse amplitude and repetition frequency but is easier to transition into the filament regime.The formation process of a single pulse is closely related to the field strength in the ionization region near the needle tip.Hence,parameters such as the pulse rising edge time and falling edge time show minimal variation with voltage.The amount of charge generated per unit time is primarily influenced by the repetition frequency.Consequently,the electrostatic ionizer produces the highest,most stable,and most uniform charges if it operates in the periodic streamer regime.展开更多
This study explores the combination of ultrasound technology with a detection algorithm to categorize flow regimes in bubble columns used for aeration in aquaculture.An ultrasonic velocity profiler is used to obtain t...This study explores the combination of ultrasound technology with a detection algorithm to categorize flow regimes in bubble columns used for aeration in aquaculture.An ultrasonic velocity profiler is used to obtain the standard deviation of the bubble velocity distributed throughout the column.The bubble velocity data for three known flow regimes were used to develop a probability density function(PDF)classification model.The experimental apparatus consisted of a circular tank equipped with a bubble generator and gas hold-up monitoring systems.The flow regimes of the experimental fluid were determined,and the classification was conducted via the PDF method.The results demonstrate that the classification accuracy is not lower than that of traditional machine learning methods.展开更多
Marginal seas,as transitional zones,are closely connected to the open ocean and adjacent coastal systems.Their circulations often exhibit strong oscillatory behavior that shapes heat and salt transport,nutrient cyclin...Marginal seas,as transitional zones,are closely connected to the open ocean and adjacent coastal systems.Their circulations often exhibit strong oscillatory behavior that shapes heat and salt transport,nutrient cycling,and regional ocean-atmosphere interactions.However,the characteristics and underlying dynamics of these oscillations remain insufficiently understood.Using the unique three-layer alternating circulation in the South China Sea as an example,we show that the system undergoes a pronounced regime transition from 1993-2008 to 2009-2018.This transition is closely linked to the phase change of the Pacific Decadal Oscillation.Specifically,upper-layer cyclonic circulation intensifies during the pre-2009 but weakens during the post-2009 period,while the middle-layer anticyclonic circulation exhibits the opposite pattern.In contrast,the deep-layer circulation strengthens substantially during the post-20o9 period.These regime transitions arise from the interplay of surface wind forcing,the external exchanging current with the Pacific,and topographically modulated internal vertical coupling.The decadal trend of the upper-layer circulation is primarily wind-driven.The weakening of middle-layer circulation during pre-2oo9 is governed by pressure torque influenced by the upperlayer,whereas its post-2009 strengthening is attributed to vortex stretching associated with enhanced deep intrusion from the Pacific and a stronger deep-layer circulation.The findings clarify the oscillatory nature of South China Sea layered circulation under climate variability and highlight its role in regulating regional mass transport and ocean-atmosphere interaction.展开更多
[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon （CToc）, a...[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon （CToc）, active carbon （CA） and mineralized carbon （CM） were analyzed, and carbon pool active （A）, carbon pool active index （A/）, carbon pool index （CPI） and carbon pool management index （CPMi） for each treat- ment were calculated. [Result] Compared with the unfertilized treatment （CK）, CToc, CA, CM and the available ratio of soil carbon were increased in the treatment of re- turning early season and late season rice straws to field. With the same nutrient application, CToc, CA and the available ratio of soil carbon in the field with straw re- turned to field were higher than that of straw incineration and no straw returning, and the change in soil CA content was more significant. The difference in CPMI be- tween different treatments reached significant or very significant level, and the value was in the order of straw directly returned to field 〉 straw returned to field after in- cineration 〉 no straw returned to field. [Conclusion] This study provided theoretical bases for the increase of soil CA content and soil fertility in double rice fields.展开更多
[Objective] The aim was to find a suitable weaning regime, including weaning period and weaning feed, for Angui//a mormorata glass eels. [Method] A weaning processing experiment was conducted indoor in fiberglass tank...[Objective] The aim was to find a suitable weaning regime, including weaning period and weaning feed, for Angui//a mormorata glass eels. [Method] A weaning processing experiment was conducted indoor in fiberglass tanks, two kinds of artificial feeds （eel grower powder feed and eel grower piece feed） were selected as weaning diets against a control group fed on natural food （minced octopus flesh）, two weaning periods, 5 and 15 d, were introduced in weaning experiment. [Result] The growth rate and survival rate of the groups with 15-day＇s weaning period were higher than that of the groups with 5-day＇s weaning period, revealing that a 20% increase every 3 d from 0% to 100% in the proportion of grower paste in the minced octopus flesh during weaning is suitable for A. mormorata glass eels. [Conclusion] A. mormorata glass eels can be weaned from natural food to the commer- cially available eel grower feeds over a certain weaning period, and of the artificial feeds with same ingredients and nutrient, A. mormorata glass eels accepted powder feed more readily over 28 d than piece feed.展开更多
This study investigates the influence of different curing regimes on the microstructure and macro properties of ultra-high performance fiber reinforced cementitious composite （UHPFRCC）, and aims to discover whether ...This study investigates the influence of different curing regimes on the microstructure and macro properties of ultra-high performance fiber reinforced cementitious composite （UHPFRCC）, and aims to discover whether it is possible to produce qualified UHPFRCC using different curing regimes. A control mix of UHPFRCC is prepared. The mechanical performance and the short-term durability of the UHPFRCC matrix under three curing regimes are studied. In addition, the microstructures of the UHPFRCC matrix with different curing conditions are analyzed by combining scanning electron microscopy （SEM） and mercury intrusion porosimetry （MIP）. The results explore how different UHPFRCC curing regimes affect its microstructure and how the microstructure affects its macro behavior. Heat and steam curing for 3 d is succeeded to produce the UHPFRCC with nearly the same mechanical properties and durability as those of the 90 d standard curing. However, the heat cured UHPFRCC does not show great resistance to chloride-ion penetration.展开更多
Field irrigation experiments were conducted in the Hetao Irrigation District of Inner Mongolia,China,to study the effects of irrigation regimes on salt leaching in the soil profile.The data were used to calibrate and ...Field irrigation experiments were conducted in the Hetao Irrigation District of Inner Mongolia,China,to study the effects of irrigation regimes on salt leaching in the soil profile.The data were used to calibrate and validate the HYDRUS-1D model.The results demonstrated that the model can accurately simulate the water and salt dynamics in the soil profile.The HYDRUS-1D model was then used to simulate 15 distinct irrigation scenarios.The results of the simulation indicated that irrigation amount did not have a significant effect on soil water storage but that increases in irrigation amount could accelerate salt leaching.However,when the irrigation amount was larger than 20 cm,the acceleration was not obvious.Compared with irrigating only once,intermittent irrigation had a better effect on increasing soil water storage and salt leaching,but excessive irrigation times and intervals did not improve salt leaching.In addition,we found that the irrigation regime of 20 cm,irrigated twice at 1-d intervals,might significantly increase salt leaching in the plough layer and decrease the risks of deep seepage and groundwater contamination.展开更多
Based on the field-survey prototype hydrology data in typical years, the effect during the running periods of different dispatch modes of the Three Gorges Reservoir on the water regimes in Dongting Lake area is compar...Based on the field-survey prototype hydrology data in typical years, the effect during the running periods of different dispatch modes of the Three Gorges Reservoir on the water regimes in Dongting Lake area is comparatively analyzed. The results are shown as follows. （1） The influence periods are from 25 May to 10 June, from 1 July to 31 August, from 15 September to 31 October and from December to the next April, among which the influence of the water-supplement dispatch in the dry season is not very sensitive. （2） During the period under the pre-discharge dispatch, the runoff volume slightly increases as well as both the average water level and the highest water level rise in the usual year. While in the wet and dry years, the average increase in the runoff volume is 40.25×1 08 m3 and the average rises of the average water level and the highest water level are both 1.06 m. （3） As for the flood-storage dispatch, the flood volume increases slightly, in the dry and wet years, the flood volume, the average water level and the highest water level averagely reduce by 444.02×108 m3, 2.64 m and 1.42 m respectively. （4） Under the water-storage dispatch, the runoff volume slightly in- creases and the water level heightens in a sort in the usual year. And in the dry and wet years the average decreases in the runoff volume, the average water leve/and the highest water levels are respectively 185.27×108 m3, 3.13 m and 2.14 m. （5） During the period under the water-supplement dispatch, the runoff volume, the average water level and the highest water levels averagely decline by 337.7×108 m3, 1.89 m and 2.39 m respectively in the usual and wet years. However, in the dry year, the runoff volume increases as well as the average and highest water levels slightly go up.展开更多
A synthesis is given in this paper on late Mesozoic deformation pattern in the zones around the Ordos Basin based on lithostratigraphic and structural analyses. A relative chronology of the late Mesozoic tectonic stre...A synthesis is given in this paper on late Mesozoic deformation pattern in the zones around the Ordos Basin based on lithostratigraphic and structural analyses. A relative chronology of the late Mesozoic tectonic stress evolution was established from the field analyses of fault kinematics and constrained by stratigraphic contact relationships. The results show alternation of tectonic compressional and extensional regimes. The Ordos Basin and its surroundings were in weak N-S to NNE-SSW extension during the Early to Middle Jurassic, which reactivated E-W-trending basement fractures. The tectonic regime changed to a multi-directional compressional one during the Late Jurassic, which resulted in crustal shortening deformation along the marginal zones of the Ordos Basin. Then it changed to an extensional one during the Early Cretaceous, which rifted the western, northwestern and southeastern margins of the Ordos Basin. A NW-SE compression occurred during the Late Cretaceous and caused the termination of sedimentation and uplift of the Ordos Basin. This phased evolution of the late Mesozoic tectonic stress regimes and associated deformation pattern around the Ordos Basin best records the changes in regional geodynamic settings in East Asia, from the Early to Middle Jurassic post-orogenic extension following the Triassic collision between the North and South China Blocks, to the Late Jurassic multi-directional compressions produced by synchronous convergence of the three plates （the Siberian Plate to the north, Paleo-Pacific Plate to the east and Lhasa Block to the west） towards the East Asian continent. Early Cretaceous extension might be the response to collapse and lithospheric thinning of the North China Craton.展开更多
A field experiment was conducted from 1999 to 2002 to compare and evaluate the effects of nutrient and water regimes on paddy soil quality by investigating soil chemical and microbiological parameters. Four nutrient r...A field experiment was conducted from 1999 to 2002 to compare and evaluate the effects of nutrient and water regimes on paddy soil quality by investigating soil chemical and microbiological parameters. Four nutrient regimes, a control, chemical fertilizers only (CF), chemical fertilizers with swine manure (SM), and chemical fertilizers with wheat straw (WS), and two soil moisture regimes, continuous waterlogging (CWL) and alternate wetting and drying (AWD), were investigated. With SM and WS total organic carbon and total nitrogen in the paddy soil were significantly higher (P < 0.05) than those with CF. A similar effect for organic amendments was observed in the soil light fraction organic C (LFOC), water-soluble carbohydrates (WSC), and water-soluble organic C (WSOC). CWL, in particular when swine manure was incorporated into the paddy soil, markedly decreased soil redox potential (Eh) and increased total active reducing substances (ARS). Meanwhile, as compared to CF, SM and WS significantly (P < 0.05) increased soil microbial biomass C (MBC) and mineralizable carbon, with differences in AWD being higher than CWL. In addition, SM and WS treatments significantly (P < 0.05) improved rice above-ground biomass and grain yield, with AWD being greater than CWL. Thus, for ecologically sustainable agricultural management of paddy soils, long-term waterlogging should be avoided when organic manure was incorporated into paddy soil.展开更多
Peak discharge plays an important role in triggering channelized debris flows.The rainfall regimes and rainfall characteristics have been demonstrated to have important influences on peak discharge.In order to explore...Peak discharge plays an important role in triggering channelized debris flows.The rainfall regimes and rainfall characteristics have been demonstrated to have important influences on peak discharge.In order to explore the relationship between rainfall regimes and peak discharge,a measuring system was placed at the outlet of a small,debris flow-prone catchment.The facility consisted of an approximately rectangular stilling basin,ending with a sharp-crested weir.Six runoff events were recorded which provided a unique opportunity for characterizing the hydrological response of the debris flow-prone catchment.Then,a rainfall–runoff model was tested against the flow discharge measurements to have a deep understanding of hydrological response.Based on the calibrated rainfall-runoff model,twelve different artificially set rainfall patterns were regarded as the input parameters to investigate the effect of rainfall regimes on peak discharge.The results show that the rainfall patterns have a significant effect on peak discharge.The rainfall regimes which have higher peak rainfall intensity and peak rainfall point occur at the later part of rainfall process are easy to generate larger peak discharge in the condition of the same cumulative rainfall and duration.Then,in order to explore the relationship between rainfall characteristics and peak discharge under different cumulative precipitation and different duration,167 measured rainfall events were also collected.On the basis of rainfall depth,rainfall duration,and maximum hourly intensity,all the rainfall events were classified into four categories by using K-mean clustering.Rainfall regime 1 was composed of rainfall events with a moderate mean P(precipitation),a moderate D(duration),and a moderate I60(maximum hourly intensity).Rainfall regime 2 was the group of rainfall events with a high mean P,long D.Rainfall regime 3,however,had a low P and a long D.The characteristic of Rainfall regime 4 was high I60 and short duration with large P.The results show that the rainfall regime 2 and 4 are easier to generate peak discharge as the rainfall intensity plays an important role in generating peak discharge.The results in this study have implications for improving peak discharge prediction accuracy in debris flow gully.展开更多
Compared with the classical Markov repairable system, the Markov repairable system with stochastic regimes switching introduced in the paper provides a more realistic description of the practical system. The system ca...Compared with the classical Markov repairable system, the Markov repairable system with stochastic regimes switching introduced in the paper provides a more realistic description of the practical system. The system can be used to model the dynamics of a repairable system whose performance regimes switch according to the external conditions. For example, to satisfy the demand variation that is typical for the power and communication systems and reduce the cost, these systems usually adjust their operating regimes. The transition rate matrices under distinct operating regimes are assumed to be different and the sojourn times in distinct regimes are governed by a finite state Markov chain. By using the theory of Markov process, Ion channel theory, and Laplace transforms, the up time of the system are studied. A numerical example is given to illustrate the obtained results. The effect of sojourn times in distinct regimes on the availability and the up time are also discussed in the numerical example.展开更多
In this paper, ocean-atmosphere coupled regimes are identified on the basis of SVD analysis, cluster analysis and composite analysis. The coupled regimes in cold seasons are identified as the clusters of the ocean-atm...In this paper, ocean-atmosphere coupled regimes are identified on the basis of SVD analysis, cluster analysis and composite analysis. The coupled regimes in cold seasons are identified as the clusters of the ocean-atmosphere coupled states in a low dimensional phase space spanned by the first four SVD modes. Three coupled regimes are found. The first two coupled regimes reflect the ENSO episodes and the accompanying PNA patterns. The third regime, i.e., EAWM regime, is characterized by the strong EAWM activity and the specific SST anomaly. The composite analysis gives further evidences to the identification of EAWM regime and also demonstrates the dynamical process of its formation. The anomaly pattern of the tropical Pacific SSTA in the strong EAWM year differs significantly from that of the La Nina year.展开更多
Freshwater shallow lakes typically exhibit two alternative stable states under certain nutrient loadings:macrophyte-dominated and phytoplankton-dominated water regimes.An ecosystem regime shift from macrophytes to phy...Freshwater shallow lakes typically exhibit two alternative stable states under certain nutrient loadings:macrophyte-dominated and phytoplankton-dominated water regimes.An ecosystem regime shift from macrophytes to phytoplankton blooming typically reduces the number of species of invertebrates and fishes and results in the homogenization of communities in freshwater lakes.We investigated how microbial biodiversity has responded to a shift of the ecosystem regime in Dianchi Lake,which was previously fully covered with submerged macrophytes but currently harbors both ecological states.We observed marked divergence in the diversity and community composition of bacterioplankton between the two regimes.Although species richness,estimated as the number of operational taxonomic units and phylogenetic diversity(PD),was higher in the phytoplankton dominated ecosystem after this shift,the dissimilarity of bacterioplankton community across space decreased.This decrease in beta diversity was accompanied by loss of planktonic bacteria unique to the macrophyte-dominated ecosystem.Mantel tests between bacterioplankton community distances and Euclidian distance of environmental parameters indicated that this reduced bacterial community differentiation primarily reflected the loss of environmental niches,particularly in the macrophyte regime.The loss of this small-scale heterogeneity in bacterial communities should be considered when assessing long-term biodiversity changes in response to ecosystem regime conversions in freshwater lakes.展开更多
Based on 9 sheets of 1：50,000-scale regional geological survey and guided by the theory of metallogenic systems and integrated analyses of the structural and metallogenic features, this paper hereby puts forward the ...Based on 9 sheets of 1：50,000-scale regional geological survey and guided by the theory of metallogenic systems and integrated analyses of the structural and metallogenic features, this paper hereby puts forward the composite metallogenic systems of the Weihai area, Shandong Province, aiming at solving the problems on the origins and ore-controlling structures of the numerous deposits in the area. Its scientific significance is reflected in the following three aspects： （1） The basic features of the composite metallogenic systems can be recognized, which consist of two types： the Proterozoic metamorphic-hydrothermal metallogenic system and the Mesozoic magmatic-hydrothermal metallogenic system （i.e. the Indosinian-early Yanshanian contact metasomatic metallogenic series and the mid-late Yanshanian magmatic-hydrothermal metallogenic series）. The two series display arcuate and NW-right lateral arrangements and a N-S parallel zonal distribution respectively, with the corresponding mineral assemblages being Au＋Ag＋Pb＋Zn, etc.; and Cu＋Mo＋Fe, Au＋Ag＋Cu＋Pb- Zn＋Mo＋Co-Ni＋sulfides＋silicides＋K-feldspar, etc. （2） The composite metallogenic systems may be used to interpret the complicated genetic relations of the deposits. Through analyses of the relations between the three main metallogenic intervals and their corresponding source rock series （the Jingshan and Rongcheng groups; the Wendong super-unit and the early-middle Yanshanian Weideshan super-unit; and the mid-late Yanshanian Weideshan and Laoshan super-units） as well as a case study of the Fanjiabu gold deposit, we have distinguished the consanguinity between the contact metasomatic （skarn-type） metallogenic series and the magmatic-hydrothermal metallogenic series as well as the noncognate superposition between the two and the metamorphic-hydrothermal metallogenic system. （3） The composite metallogenic systems are easily related to the evolution of continental dynamic regimes. The formation of the metamorphic-hydrothermal metallogenic system has undergone transformations of three different types of tectono-dynamic regimes from extension→compression→ shearing; that of the contact metasomatic （skarn-type） metallogenic system from compression→extension→compression; and that of the magmatic-hydrothermal metallogenic system from extension →subductive compression of the Pacific Plate. The evolutions of the three types are all attributed to the opening-closing or divergence-convergence of the paleocontinent, and all their mineralization corresponds to the interval of transformation from the end of convergence to early integration of the Weihai paleocontinent. All these will benefit our deeper study of the dynamics of continental metallogenic processes.展开更多
14C-tracer technique and closed incubation method were used to study straw 14C decomposition and distribution in different fractions of newly formed humus under different moisture regimes. Decomposition of straw 14C w...14C-tracer technique and closed incubation method were used to study straw 14C decomposition and distribution in different fractions of newly formed humus under different moisture regimes. Decomposition of straw 14C was faster during the initial days, and slower thereafter. Decay rate constants of straw 14C varied from 3.29x10-3 d-1 to 7.06x10-3 d-1. After 112 d incubation, the amount of straw 14C mineralized was 1.17～1.46 times greater in submerged soils than in upland soils. of the soil residual 14C, 9.08%～15.73%was present in humic acid (HA) and 31.01%～37.62% in fulvic acid (FA). Submerged condition favored the formation of HA, and HA/FA ratio of newly formed humus (labelled) was greater in submerged soils than in upland soils. Clay minerals affected the distribution of straw 14C in different humus fractions. Proportion of 14C present in HA to 14C remaining in soil was greater in Vertisol than in Ultisol.展开更多
Composition, morphology, and structure of hydration products in hardened pastes of three kinds of blended cement（cement-silica fume, cement-quartz powder and cement-silica fume-quartz powder） hydrated under differen...Composition, morphology, and structure of hydration products in hardened pastes of three kinds of blended cement（cement-silica fume, cement-quartz powder and cement-silica fume-quartz powder） hydrated under different curing regimes（standard curing, 90 ℃ steam curing, 200 ℃ and 250 ℃ autoclave curing） were investigated by X-ray diffraction and field emission scanning electron microscope equipped with EDAX system. Results showed that the main hydration products in three kinds of hardened pastes under standard curing condition are all C-S-H gels, CH, and AFt. Under 90 ℃ steam curing condition, the main hydration products of cement-silica fume and cement-silica fume-quartz powder are C-S-H gels, whereas those of cement-quartz powder are C-S-H and CH. Under 200 or 250 ℃ autoclave curing condition, no obvious crystallized CH phase is found in hardened pastes of three kinds of blended cement, and C-S-H gels are transformed into one or more crystalline phases such as tobermorite, jennite, and xonotlite. The chemical composition and morphology of these crystalline phases depend on the composition of mixture and autoclave temperature.展开更多
Experimental investigation was conducted to study the flow regimes and discharge characteristics of plasma electrohydrodynamic atomization （EHDA） for decane （CloH22） under pulsed applied negative voltage. The expe...Experimental investigation was conducted to study the flow regimes and discharge characteristics of plasma electrohydrodynamic atomization （EHDA） for decane （CloH22） under pulsed applied negative voltage. The experimental parameters were set as the flow rate of decane from 0 mL/min to 10 mL/min and the DC charging voltage from DC 0 V to 12 V with a pulse repetition rates of 200 Hz. The flow regime of decane was observed and the volume-to-electrical charge ratio was measured. Unlike a conventional EHDA system, the results show that a corona discharge was initiated at the edge of the hollow electrode at a specific corona on-set voltage of -17 kV or -20 kV in the case with or without decane flow, respectively. This phenomenon was defined as plasma EHDA.展开更多
基金We appreciate the financial support of this work by Gorgan University of Agricultural Sciences and Natural Resources from Golestan Province(Grant No.9413184180).
文摘Drought,as the most catastrophic abiotic stress,poses a significant threat to the growth and development of plants.Among the mechanisms employed by plants to cope with drought-induced stress,abscisic acid(ABA)which is the sesquiterpene hormone,occupies a pivotal role.A hypothesis has emerged that the exogenous application of ABA can positively influence the terpenoid content of Lavandula angustifolia cv Hidcote essential oil(EO),thereby conferring enhanced resilience to drought stress.A randomized complete block design experiment was conducted with three replicationsandfour irrigation regimes,including I4[30%-40%of field capacity(FC)],I3(50%-60%FC),I2(70%-80%FC),andI1(90%-100%FC)as control.Application of ABAspraying included three concentrations,A3(30μmol·L^(-1)ABA),A2(15μmol·L^(-1)ABA),and A1 as control(distilled water).Results revealed that drought significantly affected all studied traits except for relative water content(RWC)and shoot dry mass.The ABA impact application on the observed traits was found to be dependent upon the level of drought to which the plants were exposed.Specifically,the highest levels of flavonoid content,total antioxidant activity,peroxidase(POX)activity,and EO percentage were observed under I4A2 conditions.Conversely,the highest levels of superoxide dismutase(SOD)and catalase(CAT)activity,and proline were recorded under I4A3 conditions,while the highest EO yield was obtained under I3A2 conditions.Analysis of the EO revealed that there were common indicative compounds across the varying levels of droughtandABAapplication,including linalool,camphor,borneol,bornyl formate,andcaryophyllene oxide.Theproduction pattern ofmonoterpene and sesquiterpene compounds demonstrated a distinct trend,with the highest concentration of monoterpene hydrocarbon compounds(average of 12.92%)being observed in the I2A3 treatment group,andthe highest concentration of oxygenatedmonoterpenecompounds(average of 64.76%)being recorded in the I1A1 group.Conversely,the most significant levels of sesquiterpene hydrocarboncompounds(14.98%)andoxygenated sesquiterpene compounds(10.46%)were observed in the I4A3 and I4A1 groups,respectively,showing the efficacy of monoterpenes and sesquiterpenes from the action of ABA under drought conditions.The observed results indicated that the concentration of oxygenated monoterpene compounds decreases with an increase in drought level.Conversely,the application of ABA at any given drought level appears to resulted in increased concentrations of oxygenated monoterpene compounds in the same conditions.It may be concluded that plants under high-stress drought conditions allocate more terpene precursors to the production of sesquiterpene hydrocarbon compounds,aided by ABA with the same properties.
基金funded by the Chief Scientist Program of Qinghai Province(2024-SF-102)the Joint Special Project of Sanjiangyuan National Park(LHZX-2023-02).
文摘Background As an indigenous livestock species on the Tibetan Plateau,Tibetan sheep exhibit remarkable adaptability to low temperatures and nutrient-scarce environments.During the cold season,Tibetan sheep are typically managed under two feeding regimes:barn feeding(BF)and traditional grazing(TG).However,the molecular mechanisms underlying their adaptation to these distinct management strategies remain unclear.This study aimed to investigate the adaptive strategies of rumen function in Tibetan sheep to cold-season feeding regimes by integrating analyses of rumen morphology,microbiome,metabolome,and transcriptome.Twelve healthy Tibetan sheep with similar body weights were assigned into two groups(BF vs.TG).At the end of the experiment,rumen tissues were subjected to histological observation.Multi-omics techniques were employed to evaluate the effects of cold-season feeding regimes on rumen function in Tibetan sheep.Results The ruminal papilla height,width,and muscular thickness were significantly higher in BF group.The relative abundances of Actinobacteria and Succiniclasticum were significantly elevated in the rumen of BF group,whereas Rikenellaceae,Gracilibacteria,and Lachnospiraceae showed higher abundances in the TG group.Metabolomic analysis identified 19 differential metabolites between the two groups,including upregulated compounds in BF group(fumaric acid,maltose,L-phenylalanine,and L-alanine)and TG group(e.g.,phenylacetic acid,salicyluric acid and ferulic acid).These metabolites were predominantly enriched in phenylalanine metabolism,alanine,aspartate and glutamate metabolism,and phenylalanine,tyrosine and tryptophan biosynthesis pathways.Additionally,210 differentially expressed genes(DEGs)were identified in rumen epithelium:100 upregulated DEGs in the BF group were enriched in nutrient metabolism-related pathways(e.g.,fatty acid degradation and PPAR signaling pathway),while 110 upregulated DEGs in the TG group were associated with immune-related pathways(e.g.,p53 signaling pathway and glutathione metabolism).Conclusions Among these,we observed distinct rumen functional responses to different cold-season feeding regimes in Tibetan sheep and revealed energy allocation strategies mediated by host-microbe interactions.In the BF group,Tibetan sheep adopted a"metabolic efficiency-priority"strategy,driving rumen microbiota to maximize energy capture from high-nutrient diets to support host growth.In contrast,the TG group exhibited an"environmental adaptation-priority"strategy,where rumen microbiota prioritized cellulose degradation and anti-inflammatory functions,reallocating energy toward homeostasis maintenance at the expense of rumen development and growth performance.
基金financially supported by Wuxi Yanping Electronic Technology Co.Ltd.
文摘Semiconductor electronic devices are prone to charge accumulation during production and transportation,which usually causes device breakdown.Ionizers are widely used for electrostatic elimination,and utilizing semiconductor silicon for the discharge needle material in ionizers can effectively prevent metal contamination.To investigate the discharge characteristics of silicon needles and their mode modulation mechanism,this study has established an experimental platform for silicon needle-plate discharge under positive polarity voltage.Discharge pulse parameters and optical signals were measured at varying electrode spacings.The experimental results reveal that silicon needle discharge progresses through four regimes:the spontaneous streamer,the periodic streamer,the cluster streamer,and the glow discharge.Among these,the pulse amplitude is most uniform and stable in the periodic streamer regime.In addition,shorter-gap discharge exhibits higher pulse amplitude and repetition frequency but is easier to transition into the filament regime.The formation process of a single pulse is closely related to the field strength in the ionization region near the needle tip.Hence,parameters such as the pulse rising edge time and falling edge time show minimal variation with voltage.The amount of charge generated per unit time is primarily influenced by the repetition frequency.Consequently,the electrostatic ionizer produces the highest,most stable,and most uniform charges if it operates in the periodic streamer regime.
基金supported by the Center of Excellence on Instru-mentation Technology and Automation(CEITA),Department of Instru-mentation and Electronics Engineering,Faculty of Engineering,King Mongkut’s University of Technology North Bangkok,Thailand。
文摘This study explores the combination of ultrasound technology with a detection algorithm to categorize flow regimes in bubble columns used for aeration in aquaculture.An ultrasonic velocity profiler is used to obtain the standard deviation of the bubble velocity distributed throughout the column.The bubble velocity data for three known flow regimes were used to develop a probability density function(PDF)classification model.The experimental apparatus consisted of a circular tank equipped with a bubble generator and gas hold-up monitoring systems.The flow regimes of the experimental fluid were determined,and the classification was conducted via the PDF method.The results demonstrate that the classification accuracy is not lower than that of traditional machine learning methods.
基金supported by the National Natural Science Foundation of China(42376024and 42450181)the Science and Technology Development Fund,Macao SAR(File/Project no.001/2024/SKL)+2 种基金supported by the Centre for Regional Oceans in the University of Macao(SP2025-00005-CRO)CORE,which is a joint research center for ocean research between Laoshan Laboratory and HKUSTsubstantially supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region,China(AoE/P-601/23-N and GRF 16310724).
文摘Marginal seas,as transitional zones,are closely connected to the open ocean and adjacent coastal systems.Their circulations often exhibit strong oscillatory behavior that shapes heat and salt transport,nutrient cycling,and regional ocean-atmosphere interactions.However,the characteristics and underlying dynamics of these oscillations remain insufficiently understood.Using the unique three-layer alternating circulation in the South China Sea as an example,we show that the system undergoes a pronounced regime transition from 1993-2008 to 2009-2018.This transition is closely linked to the phase change of the Pacific Decadal Oscillation.Specifically,upper-layer cyclonic circulation intensifies during the pre-2009 but weakens during the post-2009 period,while the middle-layer anticyclonic circulation exhibits the opposite pattern.In contrast,the deep-layer circulation strengthens substantially during the post-20o9 period.These regime transitions arise from the interplay of surface wind forcing,the external exchanging current with the Pacific,and topographically modulated internal vertical coupling.The decadal trend of the upper-layer circulation is primarily wind-driven.The weakening of middle-layer circulation during pre-2oo9 is governed by pressure torque influenced by the upperlayer,whereas its post-2009 strengthening is attributed to vortex stretching associated with enhanced deep intrusion from the Pacific and a stronger deep-layer circulation.The findings clarify the oscillatory nature of South China Sea layered circulation under climate variability and highlight its role in regulating regional mass transport and ocean-atmosphere interaction.
基金Supported by the National Key Technology R&D Program during the Eleventh Five-year Plan Period,China(2006BAD02A04)the Key Technology R&D Program of Jiangxi Province,China(2009BNA03800)~~
文摘[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon （CToc）, active carbon （CA） and mineralized carbon （CM） were analyzed, and carbon pool active （A）, carbon pool active index （A/）, carbon pool index （CPI） and carbon pool management index （CPMi） for each treat- ment were calculated. [Result] Compared with the unfertilized treatment （CK）, CToc, CA, CM and the available ratio of soil carbon were increased in the treatment of re- turning early season and late season rice straws to field. With the same nutrient application, CToc, CA and the available ratio of soil carbon in the field with straw re- turned to field were higher than that of straw incineration and no straw returning, and the change in soil CA content was more significant. The difference in CPMI be- tween different treatments reached significant or very significant level, and the value was in the order of straw directly returned to field 〉 straw returned to field after in- cineration 〉 no straw returned to field. [Conclusion] This study provided theoretical bases for the increase of soil CA content and soil fertility in double rice fields.
基金Supported by Xiamen Marine Research and Development Institute [K10102(1)]~~
文摘[Objective] The aim was to find a suitable weaning regime, including weaning period and weaning feed, for Angui//a mormorata glass eels. [Method] A weaning processing experiment was conducted indoor in fiberglass tanks, two kinds of artificial feeds （eel grower powder feed and eel grower piece feed） were selected as weaning diets against a control group fed on natural food （minced octopus flesh）, two weaning periods, 5 and 15 d, were introduced in weaning experiment. [Result] The growth rate and survival rate of the groups with 15-day＇s weaning period were higher than that of the groups with 5-day＇s weaning period, revealing that a 20% increase every 3 d from 0% to 100% in the proportion of grower paste in the minced octopus flesh during weaning is suitable for A. mormorata glass eels. [Conclusion] A. mormorata glass eels can be weaned from natural food to the commer- cially available eel grower feeds over a certain weaning period, and of the artificial feeds with same ingredients and nutrient, A. mormorata glass eels accepted powder feed more readily over 28 d than piece feed.
基金The Scholarship Supported by the China Scholarship Councilthe Technical Research Program from NV Bekaert SA of Belgiumthe National Natural Science Foundation of China(No.50908047)
文摘This study investigates the influence of different curing regimes on the microstructure and macro properties of ultra-high performance fiber reinforced cementitious composite （UHPFRCC）, and aims to discover whether it is possible to produce qualified UHPFRCC using different curing regimes. A control mix of UHPFRCC is prepared. The mechanical performance and the short-term durability of the UHPFRCC matrix under three curing regimes are studied. In addition, the microstructures of the UHPFRCC matrix with different curing conditions are analyzed by combining scanning electron microscopy （SEM） and mercury intrusion porosimetry （MIP）. The results explore how different UHPFRCC curing regimes affect its microstructure and how the microstructure affects its macro behavior. Heat and steam curing for 3 d is succeeded to produce the UHPFRCC with nearly the same mechanical properties and durability as those of the 90 d standard curing. However, the heat cured UHPFRCC does not show great resistance to chloride-ion penetration.
基金supported by the National"Twelfth Five-Year"Plan for Science & Technology Support Program(2011BAD25B07)the State Natural Science Fund(51279142)the Fundamental Research Fund for the Central Universities of the Ministry of Science and Technology,China.(2012206020206)
文摘Field irrigation experiments were conducted in the Hetao Irrigation District of Inner Mongolia,China,to study the effects of irrigation regimes on salt leaching in the soil profile.The data were used to calibrate and validate the HYDRUS-1D model.The results demonstrated that the model can accurately simulate the water and salt dynamics in the soil profile.The HYDRUS-1D model was then used to simulate 15 distinct irrigation scenarios.The results of the simulation indicated that irrigation amount did not have a significant effect on soil water storage but that increases in irrigation amount could accelerate salt leaching.However,when the irrigation amount was larger than 20 cm,the acceleration was not obvious.Compared with irrigating only once,intermittent irrigation had a better effect on increasing soil water storage and salt leaching,but excessive irrigation times and intervals did not improve salt leaching.In addition,we found that the irrigation regime of 20 cm,irrigated twice at 1-d intervals,might significantly increase salt leaching in the plough layer and decrease the risks of deep seepage and groundwater contamination.
基金National Natural Science Foundation of China, No.41071067 Program of the Key Discipline Construction of the Physical Geography in Hunan Province
文摘Based on the field-survey prototype hydrology data in typical years, the effect during the running periods of different dispatch modes of the Three Gorges Reservoir on the water regimes in Dongting Lake area is comparatively analyzed. The results are shown as follows. （1） The influence periods are from 25 May to 10 June, from 1 July to 31 August, from 15 September to 31 October and from December to the next April, among which the influence of the water-supplement dispatch in the dry season is not very sensitive. （2） During the period under the pre-discharge dispatch, the runoff volume slightly increases as well as both the average water level and the highest water level rise in the usual year. While in the wet and dry years, the average increase in the runoff volume is 40.25×1 08 m3 and the average rises of the average water level and the highest water level are both 1.06 m. （3） As for the flood-storage dispatch, the flood volume increases slightly, in the dry and wet years, the flood volume, the average water level and the highest water level averagely reduce by 444.02×108 m3, 2.64 m and 1.42 m respectively. （4） Under the water-storage dispatch, the runoff volume slightly in- creases and the water level heightens in a sort in the usual year. And in the dry and wet years the average decreases in the runoff volume, the average water leve/and the highest water levels are respectively 185.27×108 m3, 3.13 m and 2.14 m. （5） During the period under the water-supplement dispatch, the runoff volume, the average water level and the highest water levels averagely decline by 337.7×108 m3, 1.89 m and 2.39 m respectively in the usual and wet years. However, in the dry year, the runoff volume increases as well as the average and highest water levels slightly go up.
基金funded by Sino-Probe 08-01the National Natural Science Foundation of China(grant No40572120)
文摘A synthesis is given in this paper on late Mesozoic deformation pattern in the zones around the Ordos Basin based on lithostratigraphic and structural analyses. A relative chronology of the late Mesozoic tectonic stress evolution was established from the field analyses of fault kinematics and constrained by stratigraphic contact relationships. The results show alternation of tectonic compressional and extensional regimes. The Ordos Basin and its surroundings were in weak N-S to NNE-SSW extension during the Early to Middle Jurassic, which reactivated E-W-trending basement fractures. The tectonic regime changed to a multi-directional compressional one during the Late Jurassic, which resulted in crustal shortening deformation along the marginal zones of the Ordos Basin. Then it changed to an extensional one during the Early Cretaceous, which rifted the western, northwestern and southeastern margins of the Ordos Basin. A NW-SE compression occurred during the Late Cretaceous and caused the termination of sedimentation and uplift of the Ordos Basin. This phased evolution of the late Mesozoic tectonic stress regimes and associated deformation pattern around the Ordos Basin best records the changes in regional geodynamic settings in East Asia, from the Early to Middle Jurassic post-orogenic extension following the Triassic collision between the North and South China Blocks, to the Late Jurassic multi-directional compressions produced by synchronous convergence of the three plates （the Siberian Plate to the north, Paleo-Pacific Plate to the east and Lhasa Block to the west） towards the East Asian continent. Early Cretaceous extension might be the response to collapse and lithospheric thinning of the North China Craton.
基金1Project supported by the Knowledge Innovative Program of the Chinese Academy of Sciences (No. KZCX2-413) andthe National High Technology Research and Development Program of China (863 Program) (No. 2002AA601012).
文摘A field experiment was conducted from 1999 to 2002 to compare and evaluate the effects of nutrient and water regimes on paddy soil quality by investigating soil chemical and microbiological parameters. Four nutrient regimes, a control, chemical fertilizers only (CF), chemical fertilizers with swine manure (SM), and chemical fertilizers with wheat straw (WS), and two soil moisture regimes, continuous waterlogging (CWL) and alternate wetting and drying (AWD), were investigated. With SM and WS total organic carbon and total nitrogen in the paddy soil were significantly higher (P < 0.05) than those with CF. A similar effect for organic amendments was observed in the soil light fraction organic C (LFOC), water-soluble carbohydrates (WSC), and water-soluble organic C (WSOC). CWL, in particular when swine manure was incorporated into the paddy soil, markedly decreased soil redox potential (Eh) and increased total active reducing substances (ARS). Meanwhile, as compared to CF, SM and WS significantly (P < 0.05) increased soil microbial biomass C (MBC) and mineralizable carbon, with differences in AWD being higher than CWL. In addition, SM and WS treatments significantly (P < 0.05) improved rice above-ground biomass and grain yield, with AWD being greater than CWL. Thus, for ecologically sustainable agricultural management of paddy soils, long-term waterlogging should be avoided when organic manure was incorporated into paddy soil.
基金financially supported by the National Natural Science Foundation of China (Grant No. 41772276)Key R&D project of Zhejiang Province (Grant No. 2017C03006)China Postdoctoral Science Foundation (Grant No. 2019M652083)
文摘Peak discharge plays an important role in triggering channelized debris flows.The rainfall regimes and rainfall characteristics have been demonstrated to have important influences on peak discharge.In order to explore the relationship between rainfall regimes and peak discharge,a measuring system was placed at the outlet of a small,debris flow-prone catchment.The facility consisted of an approximately rectangular stilling basin,ending with a sharp-crested weir.Six runoff events were recorded which provided a unique opportunity for characterizing the hydrological response of the debris flow-prone catchment.Then,a rainfall–runoff model was tested against the flow discharge measurements to have a deep understanding of hydrological response.Based on the calibrated rainfall-runoff model,twelve different artificially set rainfall patterns were regarded as the input parameters to investigate the effect of rainfall regimes on peak discharge.The results show that the rainfall patterns have a significant effect on peak discharge.The rainfall regimes which have higher peak rainfall intensity and peak rainfall point occur at the later part of rainfall process are easy to generate larger peak discharge in the condition of the same cumulative rainfall and duration.Then,in order to explore the relationship between rainfall characteristics and peak discharge under different cumulative precipitation and different duration,167 measured rainfall events were also collected.On the basis of rainfall depth,rainfall duration,and maximum hourly intensity,all the rainfall events were classified into four categories by using K-mean clustering.Rainfall regime 1 was composed of rainfall events with a moderate mean P(precipitation),a moderate D(duration),and a moderate I60(maximum hourly intensity).Rainfall regime 2 was the group of rainfall events with a high mean P,long D.Rainfall regime 3,however,had a low P and a long D.The characteristic of Rainfall regime 4 was high I60 and short duration with large P.The results show that the rainfall regime 2 and 4 are easier to generate peak discharge as the rainfall intensity plays an important role in generating peak discharge.The results in this study have implications for improving peak discharge prediction accuracy in debris flow gully.
基金supported by the National Natural Science Foundation of China (71071020 60705036)Beijing Excellent Doctoral Dissertation Instructor Project of Humanities and Social Sciences(yb20091000701)
文摘Compared with the classical Markov repairable system, the Markov repairable system with stochastic regimes switching introduced in the paper provides a more realistic description of the practical system. The system can be used to model the dynamics of a repairable system whose performance regimes switch according to the external conditions. For example, to satisfy the demand variation that is typical for the power and communication systems and reduce the cost, these systems usually adjust their operating regimes. The transition rate matrices under distinct operating regimes are assumed to be different and the sojourn times in distinct regimes are governed by a finite state Markov chain. By using the theory of Markov process, Ion channel theory, and Laplace transforms, the up time of the system are studied. A numerical example is given to illustrate the obtained results. The effect of sojourn times in distinct regimes on the availability and the up time are also discussed in the numerical example.
文摘In this paper, ocean-atmosphere coupled regimes are identified on the basis of SVD analysis, cluster analysis and composite analysis. The coupled regimes in cold seasons are identified as the clusters of the ocean-atmosphere coupled states in a low dimensional phase space spanned by the first four SVD modes. Three coupled regimes are found. The first two coupled regimes reflect the ENSO episodes and the accompanying PNA patterns. The third regime, i.e., EAWM regime, is characterized by the strong EAWM activity and the specific SST anomaly. The composite analysis gives further evidences to the identification of EAWM regime and also demonstrates the dynamical process of its formation. The anomaly pattern of the tropical Pacific SSTA in the strong EAWM year differs significantly from that of the La Nina year.
基金Supported by the National Natural Science Foundation of China(Nos.U1202231,31225004)the National Science Foundation for Young Scientists of China(No.31200383)
文摘Freshwater shallow lakes typically exhibit two alternative stable states under certain nutrient loadings:macrophyte-dominated and phytoplankton-dominated water regimes.An ecosystem regime shift from macrophytes to phytoplankton blooming typically reduces the number of species of invertebrates and fishes and results in the homogenization of communities in freshwater lakes.We investigated how microbial biodiversity has responded to a shift of the ecosystem regime in Dianchi Lake,which was previously fully covered with submerged macrophytes but currently harbors both ecological states.We observed marked divergence in the diversity and community composition of bacterioplankton between the two regimes.Although species richness,estimated as the number of operational taxonomic units and phylogenetic diversity(PD),was higher in the phytoplankton dominated ecosystem after this shift,the dissimilarity of bacterioplankton community across space decreased.This decrease in beta diversity was accompanied by loss of planktonic bacteria unique to the macrophyte-dominated ecosystem.Mantel tests between bacterioplankton community distances and Euclidian distance of environmental parameters indicated that this reduced bacterial community differentiation primarily reflected the loss of environmental niches,particularly in the macrophyte regime.The loss of this small-scale heterogeneity in bacterial communities should be considered when assessing long-term biodiversity changes in response to ecosystem regime conversions in freshwater lakes.
基金the National Natural Science Foundation of China （Grants 40272051 , 40572063） the Key Foundation of National Natural Science in China （Grant 40234051）.
文摘Based on 9 sheets of 1：50,000-scale regional geological survey and guided by the theory of metallogenic systems and integrated analyses of the structural and metallogenic features, this paper hereby puts forward the composite metallogenic systems of the Weihai area, Shandong Province, aiming at solving the problems on the origins and ore-controlling structures of the numerous deposits in the area. Its scientific significance is reflected in the following three aspects： （1） The basic features of the composite metallogenic systems can be recognized, which consist of two types： the Proterozoic metamorphic-hydrothermal metallogenic system and the Mesozoic magmatic-hydrothermal metallogenic system （i.e. the Indosinian-early Yanshanian contact metasomatic metallogenic series and the mid-late Yanshanian magmatic-hydrothermal metallogenic series）. The two series display arcuate and NW-right lateral arrangements and a N-S parallel zonal distribution respectively, with the corresponding mineral assemblages being Au＋Ag＋Pb＋Zn, etc.; and Cu＋Mo＋Fe, Au＋Ag＋Cu＋Pb- Zn＋Mo＋Co-Ni＋sulfides＋silicides＋K-feldspar, etc. （2） The composite metallogenic systems may be used to interpret the complicated genetic relations of the deposits. Through analyses of the relations between the three main metallogenic intervals and their corresponding source rock series （the Jingshan and Rongcheng groups; the Wendong super-unit and the early-middle Yanshanian Weideshan super-unit; and the mid-late Yanshanian Weideshan and Laoshan super-units） as well as a case study of the Fanjiabu gold deposit, we have distinguished the consanguinity between the contact metasomatic （skarn-type） metallogenic series and the magmatic-hydrothermal metallogenic series as well as the noncognate superposition between the two and the metamorphic-hydrothermal metallogenic system. （3） The composite metallogenic systems are easily related to the evolution of continental dynamic regimes. The formation of the metamorphic-hydrothermal metallogenic system has undergone transformations of three different types of tectono-dynamic regimes from extension→compression→ shearing; that of the contact metasomatic （skarn-type） metallogenic system from compression→extension→compression; and that of the magmatic-hydrothermal metallogenic system from extension →subductive compression of the Pacific Plate. The evolutions of the three types are all attributed to the opening-closing or divergence-convergence of the paleocontinent, and all their mineralization corresponds to the interval of transformation from the end of convergence to early integration of the Weihai paleocontinent. All these will benefit our deeper study of the dynamics of continental metallogenic processes.
文摘14C-tracer technique and closed incubation method were used to study straw 14C decomposition and distribution in different fractions of newly formed humus under different moisture regimes. Decomposition of straw 14C was faster during the initial days, and slower thereafter. Decay rate constants of straw 14C varied from 3.29x10-3 d-1 to 7.06x10-3 d-1. After 112 d incubation, the amount of straw 14C mineralized was 1.17～1.46 times greater in submerged soils than in upland soils. of the soil residual 14C, 9.08%～15.73%was present in humic acid (HA) and 31.01%～37.62% in fulvic acid (FA). Submerged condition favored the formation of HA, and HA/FA ratio of newly formed humus (labelled) was greater in submerged soils than in upland soils. Clay minerals affected the distribution of straw 14C in different humus fractions. Proportion of 14C present in HA to 14C remaining in soil was greater in Vertisol than in Ultisol.
基金Funded by the National Natural Science Foundation of China(Nos.51272193,51372183,51072150)Program for New Century Excellent Talents in University(No.NCET-10-0660)the National Key Research Projects(No.2016YFB0303501)
文摘Composition, morphology, and structure of hydration products in hardened pastes of three kinds of blended cement（cement-silica fume, cement-quartz powder and cement-silica fume-quartz powder） hydrated under different curing regimes（standard curing, 90 ℃ steam curing, 200 ℃ and 250 ℃ autoclave curing） were investigated by X-ray diffraction and field emission scanning electron microscope equipped with EDAX system. Results showed that the main hydration products in three kinds of hardened pastes under standard curing condition are all C-S-H gels, CH, and AFt. Under 90 ℃ steam curing condition, the main hydration products of cement-silica fume and cement-silica fume-quartz powder are C-S-H gels, whereas those of cement-quartz powder are C-S-H and CH. Under 200 or 250 ℃ autoclave curing condition, no obvious crystallized CH phase is found in hardened pastes of three kinds of blended cement, and C-S-H gels are transformed into one or more crystalline phases such as tobermorite, jennite, and xonotlite. The chemical composition and morphology of these crystalline phases depend on the composition of mixture and autoclave temperature.
基金supported by Toyota Motor Corporat.ion, Science and Technology Commission of Shanghai Municipality of China (No. 09ZR1421200)Shanghai Maritime University of China (No. 2008462)
文摘Experimental investigation was conducted to study the flow regimes and discharge characteristics of plasma electrohydrodynamic atomization （EHDA） for decane （CloH22） under pulsed applied negative voltage. The experimental parameters were set as the flow rate of decane from 0 mL/min to 10 mL/min and the DC charging voltage from DC 0 V to 12 V with a pulse repetition rates of 200 Hz. The flow regime of decane was observed and the volume-to-electrical charge ratio was measured. Unlike a conventional EHDA system, the results show that a corona discharge was initiated at the edge of the hollow electrode at a specific corona on-set voltage of -17 kV or -20 kV in the case with or without decane flow, respectively. This phenomenon was defined as plasma EHDA.
