[Objectives]To study the phosphorus removal performance of phosphate accumulating organisms(PAOs).[Methods]Activated sludge from domestic sewage treatment plant was used as the strain source,and phosphate accumulating...[Objectives]To study the phosphorus removal performance of phosphate accumulating organisms(PAOs).[Methods]Activated sludge from domestic sewage treatment plant was used as the strain source,and phosphate accumulating organisms were screened by plate streaking method and dilution coating plate method.Six kinds of excellent phosphate accumulating organisms were obtained by metachromatic granule staining experiment,total phosphorus experiment and simulated sewage phosphorus removal experiment to assist the observation of bac-terial morphology and experiment of phosphorus removal capacity.In addition,the influencing factors of phosphorus removal capacity(nitrogen source,trace metal ions)were analyzed.[Results]In the case of simulated sewage,the phosphorus removal rate of strain b was the highest,reaching 66.25%,while the phosphorus removal rate of strain e and f was about 10%lower than that of the phosphorus uptake experiment.[Conclusions]This study is expected to provide a theoretical reference for the gradual optimization of the screening method of phosphorus re-moval bacteria in domestic sewage treatment.展开更多
According to the deficiency of the strain accumulating and releasing curves and the previous models, the strain-accumulating rate of the strain accumulating and releasing model has been deduced based on the G-R relati...According to the deficiency of the strain accumulating and releasing curves and the previous models, the strain-accumulating rate of the strain accumulating and releasing model has been deduced based on the G-R relation and the empirical formula between energy release and earthquake magnitude, where the strain-accumulating rate is relative independent of the strain-releasing rate. Five typical areas in Chinese mainland are selected on the basis of the hypothesis on active tectonic block, and small earthquakes from 1970 are imported to calculate the annual strain-accumulating rates considering the completeness of historical seismic data. Having introduced the strain-accumulating rates into the amended model, present strain phases are got. According to the present stages in their own cycles, the future earthquake tendency of each sub-region is discussed.展开更多
The strata of Jurassic was divided into three tectonic sequences and eight se- quences of third rank,according to the developing feature of the tectonic inconformity and the transforming feature of the depositional sy...The strata of Jurassic was divided into three tectonic sequences and eight se- quences of third rank,according to the developing feature of the tectonic inconformity and the transforming feature of the depositional system tracts.Also the identification and the division of the base-level cycle of different period were carried through.Therefore three cycles of super period,eight cycles of long period,twenty-four cycles of middle period and some cycles of short period were identified.From the overall character of the coal-accu- mulation in the Mesozoic,we can see that the Yan'an formation is of the best nature of coal bearing.When the coal bearing systems of Jurassic were depositing,the Ordos area is the coal accumulating basin of terrene of large scale and located in the same tectonic unit.But the local structure of different part and the paleolandform are different in the basin which resulted in the difference of the depositional environment.So the layer number and the distribution of the thickness of the coal beds are different in the different part of the ba- sin.The coal-accumulating action migrated regularly along with the development,evolve- ment and migration of the depositional systems.The layer numbers of the coal beds, which can be mined,are more in the north and west fringe of the basin,whose distributing area is extensive,and they are more steady in the landscape orientation,also the total thickness is great.Therefore the nature of coal bearing and the coal-accumulating action of different part changed obviously in the space in Ordos area.展开更多
Glycogen accumulating organisms(GAOs) are closely related to the deterioration of enhanced biological phosphorus removal systems. However, the metabolic mechanisms that drive GAOs remain unclear. Here, the two-thirds ...Glycogen accumulating organisms(GAOs) are closely related to the deterioration of enhanced biological phosphorus removal systems. However, the metabolic mechanisms that drive GAOs remain unclear. Here, the two-thirds supernatant of a reactor were decanted following the anaerobic period to enrich GAOs. Long-term monitoring demonstrated that the system was stable and exhibited typical characteristics of GAOs metabolism. Acetate was completely consumed after 60 min of the anaerobic phase. The level of glycogen decreased from 0.20 to 0.14 g/gSS during the anaerobic phase, whereas the level of glycogen significantly increased to 0.21g/gSS at the end of the aerobic period. Moreover, there was almost no phosphate release and absorption in the complete periods, thus confirming the successful construction of a GAOs enrichment system. Microbial community analysis demonstrated that Ca. Contendobacter was among the core functional genera and showed the highest activity among all of the communities. Furthermore, our study is the first to identify the involvement of the ethyl-malonyl-CoA pathway in the synthesis of polyhydroxyvalerate via croR, ccr, ecm, mcd, mch and mcl genes. The Embden-Meyerhof-Parnas(EMP) pathway was preferentially used via glgP. Furthermore, the glyoxylate cycle was the main source of ATP under anaerobic conditions, whereas the tricarboxylic acid cycle provided ATP under aerobic conditions. aceA and mdh appeared to be major modulators of the glyoxylate pathway for controlling energy flow. Collectively, our findings not only revealed the crucial metabolic mechanisms in a GAOs enrichment system but also provided insights into the potential application of Ca. Contendobacter for wastewater treatment.展开更多
Lead concentrations in roots, stems and leaves of accumulating and non accumulating ecotypes of Sedum alfredii (Hance) were studied through a hydroponic experiment with different Pb concentrations supplied as Pb(...Lead concentrations in roots, stems and leaves of accumulating and non accumulating ecotypes of Sedum alfredii (Hance) were studied through a hydroponic experiment with different Pb concentrations supplied as Pb(NO 3) 2. Lead concentrations in leaves and stems of the accumulating ecotype were 4-9 times and 3-5 times those of the non accumulating ecotype, and Pb accumulated amounts in stems and leaves of the accumulating ecotype were 4-9 times and 8-11 times higher than those of the non accumulating ecotype, respectively. The results indicated that the accumulating ecotype had better ability to transport Pb from roots to shoots. The subcellular distributions of Pb in the root, stem and leaf tissues were studied using sucrose differential centrifugation. Approximately 50% of Pb contents was found to be associated with the cell wall fraction in stems of the accumulating ecotype and the percentage increased to 80% both in roots and leaves, no matter when plants were grown with different levels of Pb. The results indicated that the distribution of Pb on cell walls of the accumulating ecotype could mainly account for the high tolerance to Pb.展开更多
Temperature is an important physical factor, which strongly influences biomass and metabolic activity. In this study, the effects of temperature on the anoxic metabolism of nitrite （NO2） to nitrous oxide （N2O） by ...Temperature is an important physical factor, which strongly influences biomass and metabolic activity. In this study, the effects of temperature on the anoxic metabolism of nitrite （NO2） to nitrous oxide （N2O） by polyphosphate accumulating organisms, and the process of the accumulation of N2O （during nitrite reduction）, which acts as an electron acceptor, were investigated using 91% ：e 4% Candidatus Accumulibacterphosphatis sludge. The results showed that N2O is accumulated when Accumulibacter first utilize nitrite instead of oxygen as the sole electron acceptor during the denitrifying phosphorus removal process. Properties such as nitrite reduction rate, phosphorus uptake rate, N2O reduction rate, and polyhydroxyalkanoate degradation rate were all influenced by temperature variation （over the range from 10 to 30℃ reaching maximum values at 25℃）. The reduction rate of N2O by N2O reductase was more sensitive to temperature when N2O was utilized as the sole electron acceptor instead of NO2, and the N2O reduction rates, ranging from 0.48 to 3.53 N2O-N/（hr.g VSS）, increased to 1.45 to 8.60 mg N2O-N/（hr·g VSS）. The kinetics processes for temperature variation of 10 to 30℃ were （01 = 1.140-1.216 and θ2 = 1.139-1.167）. In the range of 10℃ to 30℃, almost all of the anoxic stoichiometry was sensitive to temperature changes. In addition, a rise in N2O reduction activity leading to a decrease in N2O accumulation in long term operations at the optimal temperature （27℃ calculated by the Arrhenius model）.展开更多
The objective of this work is to verify a hypothesis that nitrite accumulation comes from the metabolites of denitrification phosphate accumulating organisms (DPAOs),not denitrifying bacteria.On the precondition of th...The objective of this work is to verify a hypothesis that nitrite accumulation comes from the metabolites of denitrification phosphate accumulating organisms (DPAOs),not denitrifying bacteria.On the precondition of the restriction of denitrifying bacteria in anoxic phase,static experimental test was designed using NO3-as electron acceptor,effluent was removed after sedimentation in anaerobic phase,and the same concentration solution of PO43--P was returned,so that TOC was excluded and denitrification was inhibited in the next phases.A parallel experiment was carried out simultaneously with the normal anaerobic-anoxic progress.The results showed that,in static test,by keeping the normal growth of DPAO and inhibiting denitrification of denitrifying bacteria,P-release in anaerobic and P-uptake in anoxic phase proceeded normally.DPAO had obvious effect on P-removal and the P-removal efficiency was 69%.The effluent concentration of NO3--N and NO2--N was 7.62 mg/L and 6.05 mg/L respectively,compared with parallel experiments,and nitrogen removal rate was lower.No nitrite residue was found in parallel test.Therefore,it can confirm the hypothesis that the metabolites of DPAO are both nitrogen and nitrite when nitrate is taken as electron acceptor,and nitrite is subsequently converted to nitrogen by denitrifying bacteria.展开更多
Filamentous bacteria(FB)overgrowth is an important cause of sludge bulking in wastewater treatment plants(WWTPs).However,to date,methods for the cultivation and preservation of isolated FB in the laboratory have not b...Filamentous bacteria(FB)overgrowth is an important cause of sludge bulking in wastewater treatment plants(WWTPs).However,to date,methods for the cultivation and preservation of isolated FB in the laboratory have not been completely described.Furthermore,research on whether FB can function as phosphorus accumulating organisms(PAOs)is limited.In this study,a pure strain,a Pseudomonas putida PAO-1(P.putida PAO-1)isolate with phosphorus removal functions was isolated from the biofilm of an alternating anaerobic/aerobic biofilter(AABF),and its physiological characteristics were studied.Nitrate or nitrite could be used by the strain P.putida PAO-1 as electron acceptors for denitrification during phosphorus anoxic uptake,and 0.63 mg NO-3-N was consumed to reduce 1 mg soluble orthophosphate(SOP)by P.putida PAO-1.The strain P.putida PAO-1 consumed phosphorus within the optimal pH range of 6 to 8 and the temperature range of 25℃to 35℃.Cell deformity was a main morphological trait of the strain P.putida PAO-1,and it could elongate(with an elongation rate of 300%-500%)when it was subjected to oligotrophic or high-salt stress(15 g·L-1 NaCl).The findings in this study provide a microbiological reference for understanding the special characteristics of a denitrifying PAO.展开更多
A pot experiment was conducted with two rice genotypes having different Cd concentrationsin their grains to study the effect of soil Cd level on biomass, Cd and Fe, Zn, Cr andPb accumulation in different plant parts. ...A pot experiment was conducted with two rice genotypes having different Cd concentrationsin their grains to study the effect of soil Cd level on biomass, Cd and Fe, Zn, Cr andPb accumulation in different plant parts. Cd was added into soil to form 4 levels, i.e.,0, 0.5, 2.5 and 12.5mgkg-1, respectively. The results showed that the Cd-induced reductionin biomass accumulation varied in both genotypes and growth stages. The Cd-inducedreduction in biomass became less with the progress of growth, and Xiushui63, a genotypewith relatively higher grain Cd concentration, was more severely inhibited than Xiushui217,a relatively lower Cd concentration. Both Cd concentration and accumulation in thevarious plant parts increased substantially with the increase of Cd levels. The differencebetween two genotypes in Cd concentration and accumulation became more pronounced withincreased Cd level as well as prolonged duration of exposure. Xuishui63 had much greaterCd accumulation than Xiushui217, in particular at late growth stage. Xuishui63 had aremarkably higher Cd translocation of roots to shoots than Xiushui217 in all Cd levels.The effect of Cd addition on four microelement concentrations in straw and milled ricealso varied in genotypes and Cd levels. Without Cd addition, Xiushui63 was significantlylower than Xiushui217 in the concentrations of all four elements in straw, while the casewas just opposite in milled rice. Zn, Fe and Pb concentrations decreased in milled ricewith the increase of Cd level, although the reduction extent differed in two genotypes.The results indicated that Cd concentration in rice grain is primarily dependent on theshoot Cd concentration, which is in turn mainly determined by Cd translocation from rootsto shoots.展开更多
The influences of climate change on the velocity of dry matter accumulation of spring wheat and numerical simulation in arid and semi-arid regions under the condition of rainfalled agriculture or irrigated agriculture...The influences of climate change on the velocity of dry matter accumulation of spring wheat and numerical simulation in arid and semi-arid regions under the condition of rainfalled agriculture or irrigated agriculture were quantitatively analysed by using the field experimental data. The results showed that the velocity of dry matter accumulation of spring wheat was declined with the temperature rising. The accumulating velocity would be declined 4.9 - 14.0% in irrigated agriculture area when air temperature rose in 0.5-4.0℃ ; but in rainfalled agriculture regions, the velocity of dry matter accumulation would be increased with the soil moisture increasing when air temperature rose in 0.5-1.0℃ and decreased when the air temperature rose in 3.0-4.0 ℃ .展开更多
The X-ray crystal structures of C,C,N-triaryl-substituted imine compounds, which have methoxy or hydroxy group adjacent to the imino moiety, are reported and discussed in comparison with those of the precursor ketone ...The X-ray crystal structures of C,C,N-triaryl-substituted imine compounds, which have methoxy or hydroxy group adjacent to the imino moiety, are reported and discussed in comparison with those of the precursor ketone compounds, 1-(4-chlorobenzoyl)-2,7-dimethoxynaphthalene and 1-(4-chlorobenzoyl)-2-hydroxy-7-methoxynaphthalene. In crystals, three aromatic rings in a molecule of the methyl ether-retained imine compound are positioned almost perpendicularly to each other by giving non-coplanar spatial organization of the single molecular structure [dihedral angles: 85.32(18)° for C-linked phenyl ring and naphthalene ring;79.27(17)° for N-linked phenyl ring and naphthalene ring;84.78(17)° for C-linked phenyl ring and N-linked phenyl ring]. Spatial organization of the analogous methyl ether-cleaved imine compound has essentially same topology [dihedral angles 80.39(6)° for the C-linked phenyl ring and naphthalene ring;82.35(6)° for the N-linked phenyl ring and naphthalene ring;87.09(7)° for C- and N-linked phenyl rings]. These structural features of triarylimines apparently differ from those of the precursor ketones. Two aromatic rings in the methyl ether-cleaved ketone compound make smaller dihedral angle [58.10(6)°] by intramolecular hydrogen bond between ketonic carbonyl group and hydroxy group [2.5573(16) A] than that of the methyl ether-retained ketone [72.06(7)°]. In molecular packing, the methyl ether-retained imine forms tubular molecular alignments composed of R—S dimeric molecular pairs, whereas the methyl ether-retained ketone affords consecutively stacks of one configurated molecules.展开更多
Superhigh organosulfur coal has received considerable attention 'chemically as well as geologically,because from it we could get much useful chemical information for removing organosulfur from coal.By studying it,...Superhigh organosulfur coal has received considerable attention 'chemically as well as geologically,because from it we could get much useful chemical information for removing organosulfur from coal.By studying it, we could also find out the factors af-展开更多
Arsenic(As)pollution seriously threatens human and ecological health.Microalgal cell wall and extracellular polymeric substances(EPS)are known to interactwith As,but their roles in the As resistance,accumulation and s...Arsenic(As)pollution seriously threatens human and ecological health.Microalgal cell wall and extracellular polymeric substances(EPS)are known to interactwith As,but their roles in the As resistance,accumulation and speciation inmicroalgae remain unclear.Here,we used two strains of Chlamydomonas reinhardtii,namely CC-125(wild type)and CC-503(cell walldeficientmutant),to examine the algal growth,EPS synthesis,As adsorption,absorption and transformation under 10–1000μg/L As(III)and As(V)treatments for 96 h.In both strains,the As absorption increased after the EPS removal,but the growth,As adsorption,and transformation of C.reinhardtii declined.The CC-125 strain was more tolerant to As stress and more efficient in EPS production,As accumulation,and redox transformation than CC-503,irrespective of EPS presence or absence.Three-dimension excitation-emission matrix(3DEEM)and attenuated total reflectance infrared spectroscopy(ATR-IR)analyses showed that As was bound with functional groups in the EPS and cell wall,such as-COOH,NH and-OH in proteins,polysaccharides and amino acids.Together,this study demonstrated that EPS and cell wall acted as barriers to lower the As uptake by C.reinhardtii.However,the cell wall mutant strain wasmore susceptible to As toxicity due to lower EPS induction and higher As absorption.展开更多
Sucrose transporters(SUTs)play a crucial role in carbon allocation from the source leaf to the sink end,and the function of SUTs varies among family members.However,the genome-wide identifcation of the SUT superfamily...Sucrose transporters(SUTs)play a crucial role in carbon allocation from the source leaf to the sink end,and the function of SUTs varies among family members.However,the genome-wide identifcation of the SUT superfamily in Camellia oleifera is lacking,and their biological function remains elusive.In this study,four SUT genes-designated Co SUT1-4-were identifed in C.oleifera through a genome-wide analysis and classifed into three subfamilies.We used a combination of cis-acting elements analysis,mRNA quantifcation,histochemical analysis,and heterologous transformation to evaluate the expression profiles and functions of these SUTs.A key finding is that CoSUT4,localized on the plasma membrane,is highly expressed in mature leaves and the early stage of seed development in C.oleifera.In vitro culture of C.oleifera seed revealed the responsiveness of CoSUT4 to various exogenous hormones such as ABA and GA.CoSUT4 was able to restore the growth of the yeast strain SUSY7/ura3(a sucrose transport-defcient mutant)on sucrose-containing media and specifcally contributed to sucrose translocation and tissue growth in CoSUT4-overexpressed apple calli.In situ hybridization identifed chalazal nucellus and transfer cells as the action sites of CoSUT4 at the maternal-flial interface mediating sucrose transportation in oil tea seeds.CoSUT4 overexpression in Arabidopsis thaliana atsuc4 mutant restored the growth and seed yield defciencies of the mutant,leading to an increase in flled seeds and oil content.Additionally,CoSUT4 overexpression enhanced the drought and salt stress tolerance by augmenting sugar content.Overall,these fndings provide valuable insights into the function of SUTs and present promising candidates for the genetic enhancement of seed production in C.oleifera.展开更多
Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to ...Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to comprehending the developmental history and future trends of black soil,especially against the background of large-scale global cultivation and climate change.Although the importance of black soil formation and evolution cannot be ignored,the relevant research is still very scarce.In this study,a typical eight-meter-deep soil core was collected from the Keshan area of the Songnen Plain,Northeast China,where surface black soil developed on paleo-sediments.Using^(14)C dating,the formation age of the black soil was determined.Based on the characteristics of the geochemical composition,grain size and the magnetic susceptibility of the sediments,it was demonstrated that the black soil and its parent material originated from reworked loess.Furthermore,the mass transfer coefficient(τ)of some elements was determined,in order to explore the soil weathering process.By calculating the transported amount of alkaline and alkaline-earth elements,the weathering rate of parent material to black soil was found to be weak,at 0.16 kEq·ha^(-1)·year^(-1).Combining the results of dating and carbon density in the different layers of black soil,the accumulation rate of organic carbon was determined as follows:rapidly increasing in the initial period of 13.2-2.2 ka,reaching its maximum average value of 34.0 g·cm^(-2)·a^(-1)at 2.2-0.8 ka,then showing a decreasing trend with an average value of-77.5 g·cm^(-2)·a^(-1).Compared with regional climate change,Keshan black soil has developed under a colder and wetter climate during the Holocene.Predictably,ongoing global warming may lead to the degradation of black soils in the Songnen Plain,as well as in other regions.Our results will enrich geological knowledge of black soil formation and future evolutionary trends.展开更多
Friction rolling additive manufacturing(FRAM)is a solid-state additive manufacturing technology that plasticizes the feed and deposits a material using frictional heat generated by the tool head.The thermal efficiency...Friction rolling additive manufacturing(FRAM)is a solid-state additive manufacturing technology that plasticizes the feed and deposits a material using frictional heat generated by the tool head.The thermal efficiency of FRAM,which depends only on friction to generate heat,is low,and the thermal-accumulation effect of the deposition process must be addressed.An FRAM heat-balance-control method that combines plasma-arc preheating and instant water cooling(PC-FRAM)is devised in this study,and a temperature field featuring rapidly increasing and decreasing temperature is constructed around the tool head.Additionally,2195-T87 Al-Li alloy is used as the feed material,and the effects of heating and cooling rates on the microstructure and mechanical properties are investigated.The results show that water cooling significantly improves heat accumulation during the deposition process.The cooling rate increases by 11.7 times,and the high-temperature residence time decreases by more than 50%.The grain size of the PC-FRAM sample is the smallest,i.e.,3.77±1.03μm,its dislocation density is the highest,and the number density of precipitates is the highest,the size of precipitates is the smallest,which shows the best precipitation-strengthening effect.The hardness test results are consistent with the precipitation distribution.The ultimate tensile strength,yield strength and elongation of the PC-FRAM samples are the highest(351±15.6 MPa,251.3±15.8 MPa and 16.25%±1.25%,respectively)among the samples investigated.The preheating and water-cooling-assisted deposition simultaneously increases the tensile strength and elongation of the deposited samples.The combination of preheating and instant cooling improves the deposition efficiency of FRAM and weakens the thermal-softening effect.展开更多
The Electro–Hydrostatic Actuator(EHA)is applied to drive the control surface in flightcontrol system of more electric aircraft.In EHA,the Oil-Immersed Motor Pump(OMP)serves asthe core as a power assembly.However,the ...The Electro–Hydrostatic Actuator(EHA)is applied to drive the control surface in flightcontrol system of more electric aircraft.In EHA,the Oil-Immersed Motor Pump(OMP)serves asthe core as a power assembly.However,the compact integration of the OMP presents challenges inefficiently dissipating internal heat,leading to a performance degradation of the EHA due to ele-vated temperatures.Therefore,accurately modeling and predicting the internal thermal dynamicsof the OMP hold considerable significance for monitoring the operational condition of the EHA.In view of this,a modeling method considering cumulative thermal coupling was hereby proposed.Based on the proposed method,the thermal models of the motor and the pump were established,taking into account heat accumulation and transfer.Taking the leakage oil as the heat couplingpoint between the motor and the pump,the dynamic thermal coupling model of the OMP wasdeveloped,with the thermal characteristics of the oil considered.Additionally,the comparativeexperiments were conducted to illustrate the efficiency of the proposed model.The experimentalresults demonstrate that the proposed dynamic thermal coupling model accurately captured thethermal behavior of OMP,outperforming the static thermal parameter model.Overall,thisadvancement is crucial for effectively monitoring the health of EHA and ensuring flight safety.展开更多
Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N...Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status.The nitrogen nutrition index(NNI)has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application.The decline of NNI under water-limiting conditions has been documented,although the underlying mechanism governing this decline is not fully understood.This study aimed to elucidate the reason for the decline of NNI under waterlimiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments.Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N(75 and 225 kg N ha^(-1),low N and high N)and water(120 to 510 mm,W0 to W3)co-limitation treatments.Plant N accumulation,shoot biomass(SB),plant N concentration(%N),soil nitrate-N content,actual evapotranspiration(ET_a),and yield were recorded at the stem elongation,booting,anthesis and grain filling stages.Compared to W0,W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%,12.6to 24.8%,14 to 24.8%,and 16.8 to 24.8%at stem elongation,booting,anthesis,and grain filling,respectively,across the 2018-2021 seasons.This decline in NNI under water-limiting conditions stemmed from two main factors.First,reduced ET_(a) and SB led to a greater critical N concentration(%N_(c))under water-limiting conditions,which contributed to the decline in NNI primarily under high N conditions.Second,changes in plant%N played a more significant role under low N conditions.Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions,indicating co-regulation by SB and the soil nitrate-N content.However,this regulation was influenced by water availability.Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability.Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants,leading to a positive correlation between plant N accumulation and ET_(a)across the different water-N interaction treatments.Therefore,considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions.The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.展开更多
To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conduct...To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.展开更多
Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in c...Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in coal rocks.Inspired by the discovery of shale oil and gas,and guided by“the overall exploration concept of considering coal rock as reservoir”,breakthroughs in the exploration and development of coal-rock gas have been achieved in deep coal seams with favorable preservation conditions,thereby opening up a new development frontier for the unconventional gas in coal-rock reservoirs.Based on the data from exploration and development practices,a systematic study on the accumulation mechanism of coal-rock gas has been conducted.The mechanisms of“three fields”controlling coal-rock gas accumulation are revealed.It is confirmed that the coal-rock gas is different from CBM in accumulation process.The whole petroleum systems in the Carboniferous–Permian transitional facies coal measures of the eastern margin of the Ordos Basin and in the Jurassic continental facies coal measures of the Junggar Basin are characterized,and the key research directions for further developing the whole petroleum system theory of coal measures are proposed.Coal rocks,compared to shale,possess intense hydrocarbon generation potential,strong adsorption capacity,dual-medium reservoir properties,and partial or weak oil and gas self-sealing capacity.Additionally,unlike other unconventional gas such as shale gas and tight gas,coal-rock gas exhibits more complex accumulation characteristics,and its accumulation requires a certain coal-rock play form lithological and structural traps.Coal-rock gas also has the characteristics of conventional fractured gas reservoirs.Compared with the basic theory and model of the whole petroleum system established based on detrital rock formations,coal measures have distinct characteristics and differences in coal-rock reservoirs and source-reservoir coupling.The whole petroleum system of coal measures is composed of various types of coal-measure hydrocarbon plays with coal(and dark shale)in coal measures as source rock and reservoir,and with adjacent tight layers as reservoirs or cap or transport layers.Under the action of source-reservoir coupling,coal-rock gas is accumulated in coal-rock reservoirs with good preservation conditions,tight oil/gas is accumulated in tight layers,conventional oil/gas is accumulated in traps far away from sources,and coalbed methane is accumulated in coal-rock reservoirs damaged by later geological processes.The proposed whole petroleum system of coal measures represents a novel type of whole petroleum system.展开更多
基金Supported by Zhaoqing University Innovation and Entrepreneurship Training Program for College Students(202310580018).
文摘[Objectives]To study the phosphorus removal performance of phosphate accumulating organisms(PAOs).[Methods]Activated sludge from domestic sewage treatment plant was used as the strain source,and phosphate accumulating organisms were screened by plate streaking method and dilution coating plate method.Six kinds of excellent phosphate accumulating organisms were obtained by metachromatic granule staining experiment,total phosphorus experiment and simulated sewage phosphorus removal experiment to assist the observation of bac-terial morphology and experiment of phosphorus removal capacity.In addition,the influencing factors of phosphorus removal capacity(nitrogen source,trace metal ions)were analyzed.[Results]In the case of simulated sewage,the phosphorus removal rate of strain b was the highest,reaching 66.25%,while the phosphorus removal rate of strain e and f was about 10%lower than that of the phosphorus uptake experiment.[Conclusions]This study is expected to provide a theoretical reference for the gradual optimization of the screening method of phosphorus re-moval bacteria in domestic sewage treatment.
基金State Key Basic Research Development and Programming Project of China (G19980407) and Social Commonweal Research Project of the Ministry of Science and Technology (2002DIA10001).
文摘According to the deficiency of the strain accumulating and releasing curves and the previous models, the strain-accumulating rate of the strain accumulating and releasing model has been deduced based on the G-R relation and the empirical formula between energy release and earthquake magnitude, where the strain-accumulating rate is relative independent of the strain-releasing rate. Five typical areas in Chinese mainland are selected on the basis of the hypothesis on active tectonic block, and small earthquakes from 1970 are imported to calculate the annual strain-accumulating rates considering the completeness of historical seismic data. Having introduced the strain-accumulating rates into the amended model, present strain phases are got. According to the present stages in their own cycles, the future earthquake tendency of each sub-region is discussed.
基金National Basis Research Program of China(2003CB214608)
文摘The strata of Jurassic was divided into three tectonic sequences and eight se- quences of third rank,according to the developing feature of the tectonic inconformity and the transforming feature of the depositional system tracts.Also the identification and the division of the base-level cycle of different period were carried through.Therefore three cycles of super period,eight cycles of long period,twenty-four cycles of middle period and some cycles of short period were identified.From the overall character of the coal-accu- mulation in the Mesozoic,we can see that the Yan'an formation is of the best nature of coal bearing.When the coal bearing systems of Jurassic were depositing,the Ordos area is the coal accumulating basin of terrene of large scale and located in the same tectonic unit.But the local structure of different part and the paleolandform are different in the basin which resulted in the difference of the depositional environment.So the layer number and the distribution of the thickness of the coal beds are different in the different part of the ba- sin.The coal-accumulating action migrated regularly along with the development,evolve- ment and migration of the depositional systems.The layer numbers of the coal beds, which can be mined,are more in the north and west fringe of the basin,whose distributing area is extensive,and they are more steady in the landscape orientation,also the total thickness is great.Therefore the nature of coal bearing and the coal-accumulating action of different part changed obviously in the space in Ordos area.
基金supported by the National Natural Science Foundation of China (No.51678565)the Special Fund of China (No.AWS18J004)+1 种基金the Tianjin Natural Science Foundation (Nos.19JCYBJC_(2)3800, 19JCZDJC_(3)9800)the National Key R&D Program of China (No.2018YFD0800104)。
文摘Glycogen accumulating organisms(GAOs) are closely related to the deterioration of enhanced biological phosphorus removal systems. However, the metabolic mechanisms that drive GAOs remain unclear. Here, the two-thirds supernatant of a reactor were decanted following the anaerobic period to enrich GAOs. Long-term monitoring demonstrated that the system was stable and exhibited typical characteristics of GAOs metabolism. Acetate was completely consumed after 60 min of the anaerobic phase. The level of glycogen decreased from 0.20 to 0.14 g/gSS during the anaerobic phase, whereas the level of glycogen significantly increased to 0.21g/gSS at the end of the aerobic period. Moreover, there was almost no phosphate release and absorption in the complete periods, thus confirming the successful construction of a GAOs enrichment system. Microbial community analysis demonstrated that Ca. Contendobacter was among the core functional genera and showed the highest activity among all of the communities. Furthermore, our study is the first to identify the involvement of the ethyl-malonyl-CoA pathway in the synthesis of polyhydroxyvalerate via croR, ccr, ecm, mcd, mch and mcl genes. The Embden-Meyerhof-Parnas(EMP) pathway was preferentially used via glgP. Furthermore, the glyoxylate cycle was the main source of ATP under anaerobic conditions, whereas the tricarboxylic acid cycle provided ATP under aerobic conditions. aceA and mdh appeared to be major modulators of the glyoxylate pathway for controlling energy flow. Collectively, our findings not only revealed the crucial metabolic mechanisms in a GAOs enrichment system but also provided insights into the potential application of Ca. Contendobacter for wastewater treatment.
文摘Lead concentrations in roots, stems and leaves of accumulating and non accumulating ecotypes of Sedum alfredii (Hance) were studied through a hydroponic experiment with different Pb concentrations supplied as Pb(NO 3) 2. Lead concentrations in leaves and stems of the accumulating ecotype were 4-9 times and 3-5 times those of the non accumulating ecotype, and Pb accumulated amounts in stems and leaves of the accumulating ecotype were 4-9 times and 8-11 times higher than those of the non accumulating ecotype, respectively. The results indicated that the accumulating ecotype had better ability to transport Pb from roots to shoots. The subcellular distributions of Pb in the root, stem and leaf tissues were studied using sucrose differential centrifugation. Approximately 50% of Pb contents was found to be associated with the cell wall fraction in stems of the accumulating ecotype and the percentage increased to 80% both in roots and leaves, no matter when plants were grown with different levels of Pb. The results indicated that the distribution of Pb on cell walls of the accumulating ecotype could mainly account for the high tolerance to Pb.
基金supported by the National High Technology Research and Development Program (863) of China (No. 2012AA063406)the National Natural Science Foundation of China (No. 51008005)
文摘Temperature is an important physical factor, which strongly influences biomass and metabolic activity. In this study, the effects of temperature on the anoxic metabolism of nitrite （NO2） to nitrous oxide （N2O） by polyphosphate accumulating organisms, and the process of the accumulation of N2O （during nitrite reduction）, which acts as an electron acceptor, were investigated using 91% ：e 4% Candidatus Accumulibacterphosphatis sludge. The results showed that N2O is accumulated when Accumulibacter first utilize nitrite instead of oxygen as the sole electron acceptor during the denitrifying phosphorus removal process. Properties such as nitrite reduction rate, phosphorus uptake rate, N2O reduction rate, and polyhydroxyalkanoate degradation rate were all influenced by temperature variation （over the range from 10 to 30℃ reaching maximum values at 25℃）. The reduction rate of N2O by N2O reductase was more sensitive to temperature when N2O was utilized as the sole electron acceptor instead of NO2, and the N2O reduction rates, ranging from 0.48 to 3.53 N2O-N/（hr.g VSS）, increased to 1.45 to 8.60 mg N2O-N/（hr·g VSS）. The kinetics processes for temperature variation of 10 to 30℃ were （01 = 1.140-1.216 and θ2 = 1.139-1.167）. In the range of 10℃ to 30℃, almost all of the anoxic stoichiometry was sensitive to temperature changes. In addition, a rise in N2O reduction activity leading to a decrease in N2O accumulation in long term operations at the optimal temperature （27℃ calculated by the Arrhenius model）.
基金Sponsored by the Key Project of the National Natural Science Foundation of China (Grant No. 50638020)
文摘The objective of this work is to verify a hypothesis that nitrite accumulation comes from the metabolites of denitrification phosphate accumulating organisms (DPAOs),not denitrifying bacteria.On the precondition of the restriction of denitrifying bacteria in anoxic phase,static experimental test was designed using NO3-as electron acceptor,effluent was removed after sedimentation in anaerobic phase,and the same concentration solution of PO43--P was returned,so that TOC was excluded and denitrification was inhibited in the next phases.A parallel experiment was carried out simultaneously with the normal anaerobic-anoxic progress.The results showed that,in static test,by keeping the normal growth of DPAO and inhibiting denitrification of denitrifying bacteria,P-release in anaerobic and P-uptake in anoxic phase proceeded normally.DPAO had obvious effect on P-removal and the P-removal efficiency was 69%.The effluent concentration of NO3--N and NO2--N was 7.62 mg/L and 6.05 mg/L respectively,compared with parallel experiments,and nitrogen removal rate was lower.No nitrite residue was found in parallel test.Therefore,it can confirm the hypothesis that the metabolites of DPAO are both nitrogen and nitrite when nitrate is taken as electron acceptor,and nitrite is subsequently converted to nitrogen by denitrifying bacteria.
基金National Natural Science Foundation of China(No.21777024)National Key Research and Development Project,China(No.2019YFC0408503)。
文摘Filamentous bacteria(FB)overgrowth is an important cause of sludge bulking in wastewater treatment plants(WWTPs).However,to date,methods for the cultivation and preservation of isolated FB in the laboratory have not been completely described.Furthermore,research on whether FB can function as phosphorus accumulating organisms(PAOs)is limited.In this study,a pure strain,a Pseudomonas putida PAO-1(P.putida PAO-1)isolate with phosphorus removal functions was isolated from the biofilm of an alternating anaerobic/aerobic biofilter(AABF),and its physiological characteristics were studied.Nitrate or nitrite could be used by the strain P.putida PAO-1 as electron acceptors for denitrification during phosphorus anoxic uptake,and 0.63 mg NO-3-N was consumed to reduce 1 mg soluble orthophosphate(SOP)by P.putida PAO-1.The strain P.putida PAO-1 consumed phosphorus within the optimal pH range of 6 to 8 and the temperature range of 25℃to 35℃.Cell deformity was a main morphological trait of the strain P.putida PAO-1,and it could elongate(with an elongation rate of 300%-500%)when it was subjected to oligotrophic or high-salt stress(15 g·L-1 NaCl).The findings in this study provide a microbiological reference for understanding the special characteristics of a denitrifying PAO.
基金Zhejiang Provincial Natural Science Foundation(M303510)British Council(SHA/992/310),Science and Technology Department of Zhejiang Province(2003C32049)Science and Technology Bureau of Jiaxing,Zhej iang Province,China(0110,20021034)for their financial supports.
文摘A pot experiment was conducted with two rice genotypes having different Cd concentrationsin their grains to study the effect of soil Cd level on biomass, Cd and Fe, Zn, Cr andPb accumulation in different plant parts. Cd was added into soil to form 4 levels, i.e.,0, 0.5, 2.5 and 12.5mgkg-1, respectively. The results showed that the Cd-induced reductionin biomass accumulation varied in both genotypes and growth stages. The Cd-inducedreduction in biomass became less with the progress of growth, and Xiushui63, a genotypewith relatively higher grain Cd concentration, was more severely inhibited than Xiushui217,a relatively lower Cd concentration. Both Cd concentration and accumulation in thevarious plant parts increased substantially with the increase of Cd levels. The differencebetween two genotypes in Cd concentration and accumulation became more pronounced withincreased Cd level as well as prolonged duration of exposure. Xuishui63 had much greaterCd accumulation than Xiushui217, in particular at late growth stage. Xuishui63 had aremarkably higher Cd translocation of roots to shoots than Xiushui217 in all Cd levels.The effect of Cd addition on four microelement concentrations in straw and milled ricealso varied in genotypes and Cd levels. Without Cd addition, Xiushui63 was significantlylower than Xiushui217 in the concentrations of all four elements in straw, while the casewas just opposite in milled rice. Zn, Fe and Pb concentrations decreased in milled ricewith the increase of Cd level, although the reduction extent differed in two genotypes.The results indicated that Cd concentration in rice grain is primarily dependent on theshoot Cd concentration, which is in turn mainly determined by Cd translocation from rootsto shoots.
文摘The influences of climate change on the velocity of dry matter accumulation of spring wheat and numerical simulation in arid and semi-arid regions under the condition of rainfalled agriculture or irrigated agriculture were quantitatively analysed by using the field experimental data. The results showed that the velocity of dry matter accumulation of spring wheat was declined with the temperature rising. The accumulating velocity would be declined 4.9 - 14.0% in irrigated agriculture area when air temperature rose in 0.5-4.0℃ ; but in rainfalled agriculture regions, the velocity of dry matter accumulation would be increased with the soil moisture increasing when air temperature rose in 0.5-1.0℃ and decreased when the air temperature rose in 3.0-4.0 ℃ .
文摘The X-ray crystal structures of C,C,N-triaryl-substituted imine compounds, which have methoxy or hydroxy group adjacent to the imino moiety, are reported and discussed in comparison with those of the precursor ketone compounds, 1-(4-chlorobenzoyl)-2,7-dimethoxynaphthalene and 1-(4-chlorobenzoyl)-2-hydroxy-7-methoxynaphthalene. In crystals, three aromatic rings in a molecule of the methyl ether-retained imine compound are positioned almost perpendicularly to each other by giving non-coplanar spatial organization of the single molecular structure [dihedral angles: 85.32(18)° for C-linked phenyl ring and naphthalene ring;79.27(17)° for N-linked phenyl ring and naphthalene ring;84.78(17)° for C-linked phenyl ring and N-linked phenyl ring]. Spatial organization of the analogous methyl ether-cleaved imine compound has essentially same topology [dihedral angles 80.39(6)° for the C-linked phenyl ring and naphthalene ring;82.35(6)° for the N-linked phenyl ring and naphthalene ring;87.09(7)° for C- and N-linked phenyl rings]. These structural features of triarylimines apparently differ from those of the precursor ketones. Two aromatic rings in the methyl ether-cleaved ketone compound make smaller dihedral angle [58.10(6)°] by intramolecular hydrogen bond between ketonic carbonyl group and hydroxy group [2.5573(16) A] than that of the methyl ether-retained ketone [72.06(7)°]. In molecular packing, the methyl ether-retained imine forms tubular molecular alignments composed of R—S dimeric molecular pairs, whereas the methyl ether-retained ketone affords consecutively stacks of one configurated molecules.
文摘Superhigh organosulfur coal has received considerable attention 'chemically as well as geologically,because from it we could get much useful chemical information for removing organosulfur from coal.By studying it, we could also find out the factors af-
基金supported by the National Natural Science Foundation of China(Nos.32171623 and 31770548)the National Key Research and Development Program of China(Nos.2016YFD0800306 and 2017YFD0800305).
文摘Arsenic(As)pollution seriously threatens human and ecological health.Microalgal cell wall and extracellular polymeric substances(EPS)are known to interactwith As,but their roles in the As resistance,accumulation and speciation inmicroalgae remain unclear.Here,we used two strains of Chlamydomonas reinhardtii,namely CC-125(wild type)and CC-503(cell walldeficientmutant),to examine the algal growth,EPS synthesis,As adsorption,absorption and transformation under 10–1000μg/L As(III)and As(V)treatments for 96 h.In both strains,the As absorption increased after the EPS removal,but the growth,As adsorption,and transformation of C.reinhardtii declined.The CC-125 strain was more tolerant to As stress and more efficient in EPS production,As accumulation,and redox transformation than CC-503,irrespective of EPS presence or absence.Three-dimension excitation-emission matrix(3DEEM)and attenuated total reflectance infrared spectroscopy(ATR-IR)analyses showed that As was bound with functional groups in the EPS and cell wall,such as-COOH,NH and-OH in proteins,polysaccharides and amino acids.Together,this study demonstrated that EPS and cell wall acted as barriers to lower the As uptake by C.reinhardtii.However,the cell wall mutant strain wasmore susceptible to As toxicity due to lower EPS induction and higher As absorption.
基金supported by the National Natural Science Foundation of China(32071798)5·5 Engineering Research&Innovation Team Project of Beijing Forestry University,China(BLRC2023B08)。
文摘Sucrose transporters(SUTs)play a crucial role in carbon allocation from the source leaf to the sink end,and the function of SUTs varies among family members.However,the genome-wide identifcation of the SUT superfamily in Camellia oleifera is lacking,and their biological function remains elusive.In this study,four SUT genes-designated Co SUT1-4-were identifed in C.oleifera through a genome-wide analysis and classifed into three subfamilies.We used a combination of cis-acting elements analysis,mRNA quantifcation,histochemical analysis,and heterologous transformation to evaluate the expression profiles and functions of these SUTs.A key finding is that CoSUT4,localized on the plasma membrane,is highly expressed in mature leaves and the early stage of seed development in C.oleifera.In vitro culture of C.oleifera seed revealed the responsiveness of CoSUT4 to various exogenous hormones such as ABA and GA.CoSUT4 was able to restore the growth of the yeast strain SUSY7/ura3(a sucrose transport-defcient mutant)on sucrose-containing media and specifcally contributed to sucrose translocation and tissue growth in CoSUT4-overexpressed apple calli.In situ hybridization identifed chalazal nucellus and transfer cells as the action sites of CoSUT4 at the maternal-flial interface mediating sucrose transportation in oil tea seeds.CoSUT4 overexpression in Arabidopsis thaliana atsuc4 mutant restored the growth and seed yield defciencies of the mutant,leading to an increase in flled seeds and oil content.Additionally,CoSUT4 overexpression enhanced the drought and salt stress tolerance by augmenting sugar content.Overall,these fndings provide valuable insights into the function of SUTs and present promising candidates for the genetic enhancement of seed production in C.oleifera.
基金financially supported by the Science and Technology Innovation Foundation of the Command Center of Integrated Natural Resources Survey Center(KC20230002)the China Geological Survey Project(DD20230471,DD20220855 and DD20243282)+1 种基金the National Natural Science Foundation of China(41872100)the National Key R&D Plan(2022YFC2903402)。
文摘Black soil is essential for maintaining regional food security and promoting global agricultural production.Understanding the weathering process of parent material and the accumulation of organic carbon is crucial to comprehending the developmental history and future trends of black soil,especially against the background of large-scale global cultivation and climate change.Although the importance of black soil formation and evolution cannot be ignored,the relevant research is still very scarce.In this study,a typical eight-meter-deep soil core was collected from the Keshan area of the Songnen Plain,Northeast China,where surface black soil developed on paleo-sediments.Using^(14)C dating,the formation age of the black soil was determined.Based on the characteristics of the geochemical composition,grain size and the magnetic susceptibility of the sediments,it was demonstrated that the black soil and its parent material originated from reworked loess.Furthermore,the mass transfer coefficient(τ)of some elements was determined,in order to explore the soil weathering process.By calculating the transported amount of alkaline and alkaline-earth elements,the weathering rate of parent material to black soil was found to be weak,at 0.16 kEq·ha^(-1)·year^(-1).Combining the results of dating and carbon density in the different layers of black soil,the accumulation rate of organic carbon was determined as follows:rapidly increasing in the initial period of 13.2-2.2 ka,reaching its maximum average value of 34.0 g·cm^(-2)·a^(-1)at 2.2-0.8 ka,then showing a decreasing trend with an average value of-77.5 g·cm^(-2)·a^(-1).Compared with regional climate change,Keshan black soil has developed under a colder and wetter climate during the Holocene.Predictably,ongoing global warming may lead to the degradation of black soils in the Songnen Plain,as well as in other regions.Our results will enrich geological knowledge of black soil formation and future evolutionary trends.
基金supported by the National Natural Science Foundation of China(Nos.52275299,52105313)R&D Program of Beijing Municipal Education Commission(No.KM202210005036)+1 种基金Natural Science Foundation of Chongqing,China(No.CSTB2023NSCQ-MSX0701)National Defense Basic Research Projects of China(No.JCKY2022405C002).
文摘Friction rolling additive manufacturing(FRAM)is a solid-state additive manufacturing technology that plasticizes the feed and deposits a material using frictional heat generated by the tool head.The thermal efficiency of FRAM,which depends only on friction to generate heat,is low,and the thermal-accumulation effect of the deposition process must be addressed.An FRAM heat-balance-control method that combines plasma-arc preheating and instant water cooling(PC-FRAM)is devised in this study,and a temperature field featuring rapidly increasing and decreasing temperature is constructed around the tool head.Additionally,2195-T87 Al-Li alloy is used as the feed material,and the effects of heating and cooling rates on the microstructure and mechanical properties are investigated.The results show that water cooling significantly improves heat accumulation during the deposition process.The cooling rate increases by 11.7 times,and the high-temperature residence time decreases by more than 50%.The grain size of the PC-FRAM sample is the smallest,i.e.,3.77±1.03μm,its dislocation density is the highest,and the number density of precipitates is the highest,the size of precipitates is the smallest,which shows the best precipitation-strengthening effect.The hardness test results are consistent with the precipitation distribution.The ultimate tensile strength,yield strength and elongation of the PC-FRAM samples are the highest(351±15.6 MPa,251.3±15.8 MPa and 16.25%±1.25%,respectively)among the samples investigated.The preheating and water-cooling-assisted deposition simultaneously increases the tensile strength and elongation of the deposited samples.The combination of preheating and instant cooling improves the deposition efficiency of FRAM and weakens the thermal-softening effect.
基金supported by the National Key R&D Program of China(No.2021YFB2011300)the National Natural Science Foundation of China(Nos.52275044,U2233212)。
文摘The Electro–Hydrostatic Actuator(EHA)is applied to drive the control surface in flightcontrol system of more electric aircraft.In EHA,the Oil-Immersed Motor Pump(OMP)serves asthe core as a power assembly.However,the compact integration of the OMP presents challenges inefficiently dissipating internal heat,leading to a performance degradation of the EHA due to ele-vated temperatures.Therefore,accurately modeling and predicting the internal thermal dynamicsof the OMP hold considerable significance for monitoring the operational condition of the EHA.In view of this,a modeling method considering cumulative thermal coupling was hereby proposed.Based on the proposed method,the thermal models of the motor and the pump were established,taking into account heat accumulation and transfer.Taking the leakage oil as the heat couplingpoint between the motor and the pump,the dynamic thermal coupling model of the OMP wasdeveloped,with the thermal characteristics of the oil considered.Additionally,the comparativeexperiments were conducted to illustrate the efficiency of the proposed model.The experimentalresults demonstrate that the proposed dynamic thermal coupling model accurately captured thethermal behavior of OMP,outperforming the static thermal parameter model.Overall,thisadvancement is crucial for effectively monitoring the health of EHA and ensuring flight safety.
基金supported by the National Natural Science Foundation of China(51609247)the Henan Provincial Natural Science Foundation,China(222300420589,202300410553)+4 种基金the Central Public-interest Scientific Institution Basal Research Fund,China(FIRI2022-22)the Science&Technology Fundamental Resources Investigation Program,China(2022FY101601)the Science and Technology Project of Xinxiang City,Henan Province,China(GG2021024)the Major Special Science and Technology Project of Henan Province,China(221100110700)the Joint Fund of Science and Technology Research and Development Plan of Henan Province,China(Superior Discipline Cultivation)(222301420104)。
文摘Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status.The nitrogen nutrition index(NNI)has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application.The decline of NNI under water-limiting conditions has been documented,although the underlying mechanism governing this decline is not fully understood.This study aimed to elucidate the reason for the decline of NNI under waterlimiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments.Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N(75 and 225 kg N ha^(-1),low N and high N)and water(120 to 510 mm,W0 to W3)co-limitation treatments.Plant N accumulation,shoot biomass(SB),plant N concentration(%N),soil nitrate-N content,actual evapotranspiration(ET_a),and yield were recorded at the stem elongation,booting,anthesis and grain filling stages.Compared to W0,W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%,12.6to 24.8%,14 to 24.8%,and 16.8 to 24.8%at stem elongation,booting,anthesis,and grain filling,respectively,across the 2018-2021 seasons.This decline in NNI under water-limiting conditions stemmed from two main factors.First,reduced ET_(a) and SB led to a greater critical N concentration(%N_(c))under water-limiting conditions,which contributed to the decline in NNI primarily under high N conditions.Second,changes in plant%N played a more significant role under low N conditions.Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions,indicating co-regulation by SB and the soil nitrate-N content.However,this regulation was influenced by water availability.Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability.Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants,leading to a positive correlation between plant N accumulation and ET_(a)across the different water-N interaction treatments.Therefore,considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions.The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.
文摘To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.
基金Supported by the PetroChina Basic Project(2024DJ23)CNPC Science Research and Technology Development Project(2021DJ0101)。
文摘Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in coal rocks.Inspired by the discovery of shale oil and gas,and guided by“the overall exploration concept of considering coal rock as reservoir”,breakthroughs in the exploration and development of coal-rock gas have been achieved in deep coal seams with favorable preservation conditions,thereby opening up a new development frontier for the unconventional gas in coal-rock reservoirs.Based on the data from exploration and development practices,a systematic study on the accumulation mechanism of coal-rock gas has been conducted.The mechanisms of“three fields”controlling coal-rock gas accumulation are revealed.It is confirmed that the coal-rock gas is different from CBM in accumulation process.The whole petroleum systems in the Carboniferous–Permian transitional facies coal measures of the eastern margin of the Ordos Basin and in the Jurassic continental facies coal measures of the Junggar Basin are characterized,and the key research directions for further developing the whole petroleum system theory of coal measures are proposed.Coal rocks,compared to shale,possess intense hydrocarbon generation potential,strong adsorption capacity,dual-medium reservoir properties,and partial or weak oil and gas self-sealing capacity.Additionally,unlike other unconventional gas such as shale gas and tight gas,coal-rock gas exhibits more complex accumulation characteristics,and its accumulation requires a certain coal-rock play form lithological and structural traps.Coal-rock gas also has the characteristics of conventional fractured gas reservoirs.Compared with the basic theory and model of the whole petroleum system established based on detrital rock formations,coal measures have distinct characteristics and differences in coal-rock reservoirs and source-reservoir coupling.The whole petroleum system of coal measures is composed of various types of coal-measure hydrocarbon plays with coal(and dark shale)in coal measures as source rock and reservoir,and with adjacent tight layers as reservoirs or cap or transport layers.Under the action of source-reservoir coupling,coal-rock gas is accumulated in coal-rock reservoirs with good preservation conditions,tight oil/gas is accumulated in tight layers,conventional oil/gas is accumulated in traps far away from sources,and coalbed methane is accumulated in coal-rock reservoirs damaged by later geological processes.The proposed whole petroleum system of coal measures represents a novel type of whole petroleum system.
