Using Genetic Algorithms (GAs) is a powerful tool to get solution to large scale design optimization problems. This paper used GA to solve complicated design optimization problems in two different applications. The ai...Using Genetic Algorithms (GAs) is a powerful tool to get solution to large scale design optimization problems. This paper used GA to solve complicated design optimization problems in two different applications. The aims are to implement the genetic algorithm to solve these two different (nested) problems, and to get the best or optimization solutions.展开更多
A novel d!sphase supplying supported liquid membrane (DSSLM), containing supplying feed phase andsupplying stripping phase tor transport behavior ot NI(Ⅱ), have been studied. The supplying supported feed phase in...A novel d!sphase supplying supported liquid membrane (DSSLM), containing supplying feed phase andsupplying stripping phase tor transport behavior ot NI(Ⅱ), have been studied. The supplying supported feed phase included feed solution and di(2-ethyhexyl) phosphoric acid (HDEHP) as the carrier in kerosene, and supplying stripping phase included HDEHP as the cartier in kerosene and HC1 as the stripping agent. The effects of volume ratio of membrane solution to feed solution (O/F), pH, initial concentration of Ni(Ⅱ) and ionic strength in the feedsolution, volume ratio of membrane solution to stripping solution (O/S), concentration of H2SO4 solution, HDEHP concentration in the supplying stripping phase on transport of Ni(/I), the advantages of DSSLM compared to the traditional supported liquid membrane (SLM), the system stability, the reuse of membrane solution and the reten- tion of membrane phase were studied. Experimental results indicated that the optimum transpgrt of Ni(Ⅱ) was oh-tained when H2SO4 concentration was 2.00 mol'L-', HDEHP concentration was 0.120 mol·L-1, and O/S was 4· 1 in the supplying stripping phase, O/F was 1 : 10 and pH was 5.20 in the supplying feed phase. The ionic strength in supplying feed phase had no obvious effect on transport of Ni(Ⅱ). When initial Ni(Ⅱ) concentration was 2.00x 10-4 mol/L, the transport percentage of Ni(Ⅱ) was up to 93.1% in 250 min. The kinetic equation was deduced in terms of the law of mass diffusion and the interface chemistry.展开更多
In current China, the main problem existing in the rural public goods supplying system is the unbalanced condition of public goods supply, and the chief reason for which is unitary system of supply main body. Thus the...In current China, the main problem existing in the rural public goods supplying system is the unbalanced condition of public goods supply, and the chief reason for which is unitary system of supply main body. Thus the leading countermeasure for comer of public goods supply is to reform the present unitary rural public goods supplying system, to strengthen functional transfer of rural grass-roots directive organization, to adopt diversified mode and provide public goods on the base of overall planning of urban and rural areas and to implement unitary and diversified supplying strategy. In this way, supplying efficiency of the rural public goods will be improved.展开更多
The changes in grain-filling, starch accumulation and activity of enzymes associated with starch synthesis in two different hybrid rice varieties were analyzed at different N supplying dates (earlier-date-emphasized...The changes in grain-filling, starch accumulation and activity of enzymes associated with starch synthesis in two different hybrid rice varieties were analyzed at different N supplying dates (earlier-date-emphasized, mean-date-emphasized and later-date- emphasized). The results showed that the N application of later-date-emphasized could promote grain-filling rate, increase grain weight and amylopectin content. The peak of activity in three enzymes of ADPglusoce pyriphosphorylase (ADPG), starch synthesis enzyme (SSS) and starch branching enzyme (SBE) in grains of two different rice varieties was not changed obviously, but the mean and maximum activity of these three enzymes changed, and the changes of SSS and ADPG were bigger than that of SBE as N supplying date changed. The N application of earlier-date-emphasized increased SSS activity and the N application of later-date-emphasized increased ADPG and SBE activities. The mean SSS activity during whole grain-filling period, and ADPG and SBE activities at middle and late period of grain-filling were significantly or very significantly correlated with grain-filling rate and accumulating rate of amylose and amylopectin. Both of ADPG and SBE played an equal important role in the changes of amylose and amylopectin content. The N application of later-date-emphasized increased amylose and amylopectin accumulating rate.展开更多
Transgression networks in metropolitan centers need to supply a large quantity of power in a reliable manner to vital loads that are located within. A transmission network supplying such an important area must have a ...Transgression networks in metropolitan centers need to supply a large quantity of power in a reliable manner to vital loads that are located within. A transmission network supplying such an important area must have a high standard of reliability. Therefore, those transmission systems require a special form of redundancy in order to prevent sustained outages after severe contingencies such as multiple faults. This paper outlines different forms of redundancy, and the fundamental options for designing a metropolitan network based on different forms of redundancy are illustrated. Relative merits and drawbacks of network designs based on each form of redundancy are also shown.展开更多
A pot experiment was conducted to study the effects of magnesium on carbon and nitrogen metabolism of soybean at different nitrogen supplying levels. The results showed that the effects of magnesium at low nitrogen ra...A pot experiment was conducted to study the effects of magnesium on carbon and nitrogen metabolism of soybean at different nitrogen supplying levels. The results showed that the effects of magnesium at low nitrogen rate on N content, soluble protein, soluble sugar contents were not alike at different growth stage, although nodule dry weights raised, the yield and protein content of seeds decreased, however, the oil content was improved. The application of magnesium at medium and high nitrogen supplying levels promoted the uptake of N effectively, increased the soluble protein and soluble sugar contents, but the nodule dry weights of application magnesium at medium nitrogen supplying level decreased and the yield increased only a little despite the improved quality. Application of magnesium at high nitrogen supplying level raised nodule dry weights and soybean yield significantly, the quality of seeds was also improved.展开更多
Although many biological methods are used to determine soil nitrogen supplying capacity, there are certain differences in the results for different types of soils and various ways of measurement due to the complexity ...Although many biological methods are used to determine soil nitrogen supplying capacity, there are certain differences in the results for different types of soils and various ways of measurement due to the complexity of soil N conformation, the high variance of soil and microorganism, and the difference of environment. Therefore, it is not clear about which biologic incubation method is better for calcareous soil. In this study, pot experiments were performed by using 25 different calcareous surface soil samples on the Loess Plateau and taking the N uptake of wheat and corn with leaching soil initial nitrate and without leaching in pot experiments as the control to investigate the difference of eight biological incubation methods for reflecting soil nitrogen supply capacity. The eight biological methods are waterlogged incubation, aerobic incubation for 2 weeks and for 4 weeks, dry-wet alternation aerobic incubation for 2 weeks, long-term alternate leaching aerobic incubation (and N mineralization potential, No), short-term leaching aerobic incubation, microbial biomass carbon (Bc), and microbial biomass nitrogen (BN) method, respectively. Among these methods, the dry-wet alternation aerobic incubation and aerobic incubation for 4 weeks were the modification of the method of aerobic incubation for 2 weeks according to the actual farmland moisture. The results showed that the correlation coefficients between these methods and crop uptake N with leaching soil initial nitrate were 0.530, 0.700, 0.777, 0.768, 0.764 (and 0.790, No), 0.650, 0.555, and 0.465, respectively (r0.05 = 0.369, r0.0l = 0.505). While without leaching soil initial nitrate, their coefficients were 0.351, 0.963, 0.962, 0.959, 0.825 (and0.812, No), 0.963, 0.289, and 0.095, respectively (r0.05 = 0.369, r0.01 = 0.505). In conclusion, excluding the soil initial nitrate, the correlation coefficients between the eight methods and crop uptake N were, from high to low, N0, aerobic incubation for 4 weeks, dry-wet alternation aerobic incubation for 2 weeks, and long-term alternate leaching aerobic incubation, while including the soil initial nitrate the correlation coefficients between them increased significantly and the values were all beyond 0.950 for these four methods, including aerobic incubation for 2 weeks and for 4 weeks, dry-wet alternation aerobic incubation for 2 weeks and short-term leaching aerobic incubation. The waterlogged incubation method, Bc and BN in the calcareous soil, had lower correlation coefficient with crop uptake nitrogen compared with other methods. Thus, dry-wet alternation aerobic incubation for 2 weeks was a better index for evaluating calcareous soil N supply capacity due to some other methods having disadvantages and not suitable for the actual farmland characteristics.展开更多
THE age of 24 is often regarded as the prime of life - in which young people make the most of their time in college and plan their dream job. But for Li Qiang, the age of 24 means a turning point in his career. An aut...THE age of 24 is often regarded as the prime of life - in which young people make the most of their time in college and plan their dream job. But for Li Qiang, the age of 24 means a turning point in his career. An auto mechanic with five years of experience in the trade in Shijiazhuang, north China's Hebei Province, Li was re- cently promoted as the head of a team of 10 mechanics in a car repair workshop, "1 failed the entrance exam for high school and had to attend a vocational school. I never expected this choice could lead me to the career of my interest." Li told ChinAfrica.展开更多
The extensively built long-distance water transmission pipelines have become the main water sources for urban areas. To ensure the reliability and safety of the water supply, from the viewpoint of overall management, ...The extensively built long-distance water transmission pipelines have become the main water sources for urban areas. To ensure the reliability and safety of the water supply, from the viewpoint of overall management, it would be necessary to establish a system of information management for the pipeline. The monitoring, calculating and analyzing functions of the system serve to give controlling instructions and safe operating rules to the automatic equipment and technician, making sure the resistance coefficient distribution along the pipeline is reasonable; the hydraulic state transition is smooth when operating conditions change or water supply accidents occur, avoiding the damage of water hammer. This paper covered the composition structures of the information management system of long-distance water transmission pipelines and the functions of the subsystems, and finally elaborated on the approaches and steps of building a mathematics model for the analysis of dynamic hydraulic status.展开更多
Bacterial biofilms,especially those caused by multidrug-resistant bacteria,have emerged as one of the greatest dangers to global public health.The acceleration of antimicrobial resistance to conventional an-tibiotics ...Bacterial biofilms,especially those caused by multidrug-resistant bacteria,have emerged as one of the greatest dangers to global public health.The acceleration of antimicrobial resistance to conventional an-tibiotics and the severe lack of new drugs necessitates the development of novel agents for biofilm eradication.Photodynamic therapy(PDT)is a promising non-antibiotic method for treating bacterial infections.However,its application in biofilm eradication is hampered by the hypoxic microenvironment of biofilms and the physical protection of extracellular polymeric substances.In this study,we develop a composite nanoplatform with oxygen(O_(2))self-supplying and heat-sensitizing capabilities to improve the PDT efficacy against biofilms.CaO_(2)/ICG@PDA nanoparticles(CIP NPs)are fabricated by combining calcium peroxide(CaO_(2))with the photosensitizer indocyanine green(ICG)via electrostatic interactions,followed by coating with polydopamine(PDA).The CIP NPs can gradually generate O_(2)in response to the acidic microenvironment of the biofilm,thereby alleviating its hypoxic state.Under near-infrared(NIR)irradiation,the nanoplatform converts O_(2)into a significant amount of singlet oxygen(^(1)O_(2))and heat to eradicate biofilm.The generated heat enhances the release of O_(2),accelerates the generation of^(1)O_(2)in PDT,increases cell membrane permeability,and increases bacterial sensitivity to^(1)O_(2).This nanoplatform significantly improves the efficacy of PDT in eradicating biofilm-dwelling bacteria without fostering drug resistance.Experiments on biofilm eradication demonstrate that this nanoplatform can eradicate over 99.9999%of methicillin-resistant Staphylococcus aureus(MRSA)biofilms under 5-min NIR irradiation.Notably,these integrated advantages enable the system to promote the healing of MRSA biofilm-infected wounds with negligible toxicity in vivo,indicating great promise for overcoming the obstacles associated with bacterial biofilm eradication.展开更多
The building sector is one of the largest energy user and carbon emitters globally.To increase the utilization rate of renewable energy and reduce carbon dioxide emissions,the optimal technical scheme of active public...The building sector is one of the largest energy user and carbon emitters globally.To increase the utilization rate of renewable energy and reduce carbon dioxide emissions,the optimal technical scheme of active public institutions and coupled utilization of renewable energy is studied.In this study,the energy consumption of three types of public institutions in various regions of China was simulated by using DeST building energy consumption software,combined with energy conversion efficiency and data released by the National Bureau of Statistics,and the total energy demand and total energy supply of public institutions were predicted using the load density method.Based on the coupling mechanism of the MARKAL model,the optimal proportion of renewable energy in the energy supply of public buildings in different regions is determined.Through the study of the number of public institutions in various regions of China,energy consumption characteristics,construction area,and other related data,the reverse energy flow method is creatively proposed,and the active and renewable energy coupling algorithm from the energy demand side of public institutions to the energy supply side is established.The results show that the central region has the highest utilization rate of renewable energy in the public sector,reaching 36.18%.The use of renewable energy in public buildings in hot summer and warm winter zones decreased to 35.08%,and it was 12.82% in cold zones.By 2025,the proportion of renewable energy resources in China is expected to reach 29.2%.The energy coupling model and algorithm constructed in this paper can provide a basis for the coupling macro configuration of renewable energy in public institutions in China.展开更多
The liquid nitrogen(LN2)supplying system,one of the four key systems of the cryogenic wind tunnel(CWT),is an essential guarantee for the precise control,fast and safe regulation of the wind tunnel’s total temperature...The liquid nitrogen(LN2)supplying system,one of the four key systems of the cryogenic wind tunnel(CWT),is an essential guarantee for the precise control,fast and safe regulation of the wind tunnel’s total temperature.Firstly,the technical schemes,advantages and disadvantages of different LN2 supplying systems are discussed and analyzed based on the operation conditions and test requirements of different CWTs.Then,together with the development of the pilot cryogenic transonic wind tunnel(PCTW),the key technologies of the system,including the supplying mode,rapid and accurate regulation of injection pressure,development of large scale cryogenic centrifugal pump,and matching technology between pumps and pipe network,have been summarized and the solutions to the existing issues are given.Finally,a supplying process suitable for large-scale CWT is proposed,which has the ability of independent commissioning,rapid regulation,accurate control of injection pressure and transient response to the wind tunnel’s wide range of working conditions.The breakthrough in LN2 supplying system enables China to construct a CWT for the future competitive high Reynolds number aircraft.展开更多
As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scal...As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete(RC)frame structure.Different material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic performance.Floor response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions.A seismic fragility study of displacement demand is conducted based on numerical simulation.The acceleration response and displacement response of different combinations are compared.The results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes.展开更多
Traction power systems(TPSs)play a vital role in the operation of electrified railways.The transformation of conventional railway TPSs to novel structures is not only a trend to promote the development of electrified ...Traction power systems(TPSs)play a vital role in the operation of electrified railways.The transformation of conventional railway TPSs to novel structures is not only a trend to promote the development of electrified railways toward high-efficiency and resilience but also an inevitable requirement to achieve carbon neutrality target.On the basis of sorting out the power supply structures of conventional AC and DC modes,this paper first reviews the characteristics of the existing TPSs,such as weak power supply flexibility and low-energy efficiency.Furthermore,the power supply structures of various TPSs for future electrified railways are described in detail,which satisfy longer distance,low-carbon,high-efficiency,high-reliability and high-quality power supply requirements.Meanwhile,the application prospects of different traction modes are discussed from both technical and economic aspects.Eventually,this paper introduces the research progress of mixed-system electrified railways and traction power supply technologies without catenary system,speculates on the future development trends and challenges of TPSs and predicts that TPSs will be based on the continuous power supply mode,employing power electronic equipment and intelligent information technology to construct a railway comprehensive energy system with renewable energy.展开更多
In 2023,two consecutive earthquakes exceeding a magnitude of 7 occurred in Türkiye,causing severe casualties and economic losses.The damage to critical urban infrastructure and building structures,including highw...In 2023,two consecutive earthquakes exceeding a magnitude of 7 occurred in Türkiye,causing severe casualties and economic losses.The damage to critical urban infrastructure and building structures,including highways,railroads,and water supply pipelines,was particularly severe in areas where these structures intersected the seismogenic fault.Critical infrastructure projects that traverse active faults are susceptible to the influence of fault movement,pulse velocity,and ground motions.In this study,we used a unique approach to analyze the acceleration records obtained from the seismic station array(9 strong ground motion stations)located along the East Anatolian Fault(the seismogenic fault of the MW7.8 mainshock of the 2023 Türkiye earthquake doublet).The acceleration records were filtered and integrated to obtain the velocity and displacement time histories.We used the results of an on-site investigation,jointly conducted by China Earthquake Administration and Türkiye’s AFAD,to analyze the distribution of PGA,PGV,and PGD recorded by the strong motion array of the East Anatolian Fault.We found that the maximum horizontal PGA in this earthquake was 3.0 g,and the maximum co-seismic surface displacement caused by the East Anatolian Fault rupture was 6.50 m.As the fault rupture propagated southwest,the velocity pulse caused by the directional effect of the rupture increased gradually,with the maximum PGA reaching 162.3 cm/s.We also discussed the seismic safety of critical infrastructure projects traversing active faults,using two case studies of water supply pipelines in Türkiye that were damaged by earthquakes.We used a three-dimensional finite element model of the PE(polyethylene)water pipeline at the Islahiye State Hospital and fault displacement observations obtained through on-site investigation to analyze pipeline failure mechanisms.We further investigated the effect of the fault-crossing angle on seismic safety of a pipeline,based on our analysis and the failure performance of the large-diameter Thames Water pipeline during the 1999 Kocaeli earthquake.The seismic method of buried pipelines crossing the fault was summarized.展开更多
With ificreasing demand for large cylindrical forgings, a new technology--electroslag remelting (ESR) for direct manufacture of hollow ingots rather than solid ingots has been developed. The main features of the pro...With ificreasing demand for large cylindrical forgings, a new technology--electroslag remelting (ESR) for direct manufacture of hollow ingots rather than solid ingots has been developed. The main features of the process include a T-shaped current supplying mould (CSM), double power supply, an ingot withdrawing system, a metal level automatic control system based on a level sensor using the electromagnetic eddy current method, and the exchange of a consumable multi-electrode. ANSYS software was used to calculate the fluid flow and heat transfer in the slag bath 1 and metal pool of this ESR hollow ingot process with its T-shaped CSM. The mathematmal model was Verified by measuring the geometry of the liquid metal pool as observed in the macrostructure of 4650 mm (external diameter)/ 4450 mm (internal diameter) hollow ingots by sulphur print method: the. observed shape and depth of the s!ag bath were consistent with the simulated results. Simulation of the ESR process can improve understanding of the process and allow better operating parameters to be selected.展开更多
Wearable triboelectric nanogenerators(TENGs)have attracted attention owing to their ability to harvest energy from the surrounding environment without maintenance.Herein,polyetherimide-Al_(2)O_(3)(PAl)and polyvinylide...Wearable triboelectric nanogenerators(TENGs)have attracted attention owing to their ability to harvest energy from the surrounding environment without maintenance.Herein,polyetherimide-Al_(2)O_(3)(PAl)and polyvinylidene fluoride-co-hexafluoropropylene(PVDF-HFP,PH)nanofiber membranes were used as tribo-positive and tribo-negative materials,respectively.Phytic acid-doped polyaniline(PANI)/cotton fabric(PPCF)and ethylenediamine(EDA)-crosslinked PAl(EPAl)nanofiber membranes were used as triboelectrode and triboencapsulation materials,respectively.The result showed that when the PAl-PH-based TENG was shaped as a circle with a radius of 1 cm,under the pressure of 50 N,and the frequency of 0.5 Hz,the open-circuit voltage(V_(oc))and short-circuit current(I_(sc))reached the highest value of 66.6 V and-93.4 to 110.1 nA,respectively.Moreover,the PH-based TENG could be used as a fabric sensor to detect fabric composition and as a sensor-inductive switch for light bulbs or beeping warning devices.When the PAl-PH-based TENG was shaped as a 5×5 cm^(2)rectangle,a 33 pF capacitor could be charged to 15 V in 28 s.Interestingly,compared to PAl nanofiber membranes,EPAl nanofiber membranes exhibited good dyeing properties and excellent solvent resistance.The PPCF exhibited<5%resistance change after washing,bending,and stretching.展开更多
文摘Using Genetic Algorithms (GAs) is a powerful tool to get solution to large scale design optimization problems. This paper used GA to solve complicated design optimization problems in two different applications. The aims are to implement the genetic algorithm to solve these two different (nested) problems, and to get the best or optimization solutions.
基金Supported by the Action Plan for the Development of Western China of the Chinese Academy of Sciences(KZCX2-XB2-13)the Knowledge Innovation Program of the Chinese Academy of Sciences(KSCX2-YW-N-003)Research Fund for Excellent Doctoral Thesis of Xi'an University of Tehcnology(602-210805 and 602-210804)
文摘A novel d!sphase supplying supported liquid membrane (DSSLM), containing supplying feed phase andsupplying stripping phase tor transport behavior ot NI(Ⅱ), have been studied. The supplying supported feed phase included feed solution and di(2-ethyhexyl) phosphoric acid (HDEHP) as the carrier in kerosene, and supplying stripping phase included HDEHP as the cartier in kerosene and HC1 as the stripping agent. The effects of volume ratio of membrane solution to feed solution (O/F), pH, initial concentration of Ni(Ⅱ) and ionic strength in the feedsolution, volume ratio of membrane solution to stripping solution (O/S), concentration of H2SO4 solution, HDEHP concentration in the supplying stripping phase on transport of Ni(/I), the advantages of DSSLM compared to the traditional supported liquid membrane (SLM), the system stability, the reuse of membrane solution and the reten- tion of membrane phase were studied. Experimental results indicated that the optimum transpgrt of Ni(Ⅱ) was oh-tained when H2SO4 concentration was 2.00 mol'L-', HDEHP concentration was 0.120 mol·L-1, and O/S was 4· 1 in the supplying stripping phase, O/F was 1 : 10 and pH was 5.20 in the supplying feed phase. The ionic strength in supplying feed phase had no obvious effect on transport of Ni(Ⅱ). When initial Ni(Ⅱ) concentration was 2.00x 10-4 mol/L, the transport percentage of Ni(Ⅱ) was up to 93.1% in 250 min. The kinetic equation was deduced in terms of the law of mass diffusion and the interface chemistry.
文摘In current China, the main problem existing in the rural public goods supplying system is the unbalanced condition of public goods supply, and the chief reason for which is unitary system of supply main body. Thus the leading countermeasure for comer of public goods supply is to reform the present unitary rural public goods supplying system, to strengthen functional transfer of rural grass-roots directive organization, to adopt diversified mode and provide public goods on the base of overall planning of urban and rural areas and to implement unitary and diversified supplying strategy. In this way, supplying efficiency of the rural public goods will be improved.
文摘The changes in grain-filling, starch accumulation and activity of enzymes associated with starch synthesis in two different hybrid rice varieties were analyzed at different N supplying dates (earlier-date-emphasized, mean-date-emphasized and later-date- emphasized). The results showed that the N application of later-date-emphasized could promote grain-filling rate, increase grain weight and amylopectin content. The peak of activity in three enzymes of ADPglusoce pyriphosphorylase (ADPG), starch synthesis enzyme (SSS) and starch branching enzyme (SBE) in grains of two different rice varieties was not changed obviously, but the mean and maximum activity of these three enzymes changed, and the changes of SSS and ADPG were bigger than that of SBE as N supplying date changed. The N application of earlier-date-emphasized increased SSS activity and the N application of later-date-emphasized increased ADPG and SBE activities. The mean SSS activity during whole grain-filling period, and ADPG and SBE activities at middle and late period of grain-filling were significantly or very significantly correlated with grain-filling rate and accumulating rate of amylose and amylopectin. Both of ADPG and SBE played an equal important role in the changes of amylose and amylopectin content. The N application of later-date-emphasized increased amylose and amylopectin accumulating rate.
文摘Transgression networks in metropolitan centers need to supply a large quantity of power in a reliable manner to vital loads that are located within. A transmission network supplying such an important area must have a high standard of reliability. Therefore, those transmission systems require a special form of redundancy in order to prevent sustained outages after severe contingencies such as multiple faults. This paper outlines different forms of redundancy, and the fundamental options for designing a metropolitan network based on different forms of redundancy are illustrated. Relative merits and drawbacks of network designs based on each form of redundancy are also shown.
基金Sponsored by the Great Committee of Science and Technology of National Tenth "Five-year Plan" (2001BA50705-01)
文摘A pot experiment was conducted to study the effects of magnesium on carbon and nitrogen metabolism of soybean at different nitrogen supplying levels. The results showed that the effects of magnesium at low nitrogen rate on N content, soluble protein, soluble sugar contents were not alike at different growth stage, although nodule dry weights raised, the yield and protein content of seeds decreased, however, the oil content was improved. The application of magnesium at medium and high nitrogen supplying levels promoted the uptake of N effectively, increased the soluble protein and soluble sugar contents, but the nodule dry weights of application magnesium at medium nitrogen supplying level decreased and the yield increased only a little despite the improved quality. Application of magnesium at high nitrogen supplying level raised nodule dry weights and soybean yield significantly, the quality of seeds was also improved.
基金the National Natural Science Foundation of China (90502006) the Project of Innovative Group in Northwest A&F University.
文摘Although many biological methods are used to determine soil nitrogen supplying capacity, there are certain differences in the results for different types of soils and various ways of measurement due to the complexity of soil N conformation, the high variance of soil and microorganism, and the difference of environment. Therefore, it is not clear about which biologic incubation method is better for calcareous soil. In this study, pot experiments were performed by using 25 different calcareous surface soil samples on the Loess Plateau and taking the N uptake of wheat and corn with leaching soil initial nitrate and without leaching in pot experiments as the control to investigate the difference of eight biological incubation methods for reflecting soil nitrogen supply capacity. The eight biological methods are waterlogged incubation, aerobic incubation for 2 weeks and for 4 weeks, dry-wet alternation aerobic incubation for 2 weeks, long-term alternate leaching aerobic incubation (and N mineralization potential, No), short-term leaching aerobic incubation, microbial biomass carbon (Bc), and microbial biomass nitrogen (BN) method, respectively. Among these methods, the dry-wet alternation aerobic incubation and aerobic incubation for 4 weeks were the modification of the method of aerobic incubation for 2 weeks according to the actual farmland moisture. The results showed that the correlation coefficients between these methods and crop uptake N with leaching soil initial nitrate were 0.530, 0.700, 0.777, 0.768, 0.764 (and 0.790, No), 0.650, 0.555, and 0.465, respectively (r0.05 = 0.369, r0.0l = 0.505). While without leaching soil initial nitrate, their coefficients were 0.351, 0.963, 0.962, 0.959, 0.825 (and0.812, No), 0.963, 0.289, and 0.095, respectively (r0.05 = 0.369, r0.01 = 0.505). In conclusion, excluding the soil initial nitrate, the correlation coefficients between the eight methods and crop uptake N were, from high to low, N0, aerobic incubation for 4 weeks, dry-wet alternation aerobic incubation for 2 weeks, and long-term alternate leaching aerobic incubation, while including the soil initial nitrate the correlation coefficients between them increased significantly and the values were all beyond 0.950 for these four methods, including aerobic incubation for 2 weeks and for 4 weeks, dry-wet alternation aerobic incubation for 2 weeks and short-term leaching aerobic incubation. The waterlogged incubation method, Bc and BN in the calcareous soil, had lower correlation coefficient with crop uptake nitrogen compared with other methods. Thus, dry-wet alternation aerobic incubation for 2 weeks was a better index for evaluating calcareous soil N supply capacity due to some other methods having disadvantages and not suitable for the actual farmland characteristics.
文摘THE age of 24 is often regarded as the prime of life - in which young people make the most of their time in college and plan their dream job. But for Li Qiang, the age of 24 means a turning point in his career. An auto mechanic with five years of experience in the trade in Shijiazhuang, north China's Hebei Province, Li was re- cently promoted as the head of a team of 10 mechanics in a car repair workshop, "1 failed the entrance exam for high school and had to attend a vocational school. I never expected this choice could lead me to the career of my interest." Li told ChinAfrica.
基金Hi-Tech Research and Development Program of China (863 Program)(2002AA601140)
文摘The extensively built long-distance water transmission pipelines have become the main water sources for urban areas. To ensure the reliability and safety of the water supply, from the viewpoint of overall management, it would be necessary to establish a system of information management for the pipeline. The monitoring, calculating and analyzing functions of the system serve to give controlling instructions and safe operating rules to the automatic equipment and technician, making sure the resistance coefficient distribution along the pipeline is reasonable; the hydraulic state transition is smooth when operating conditions change or water supply accidents occur, avoiding the damage of water hammer. This paper covered the composition structures of the information management system of long-distance water transmission pipelines and the functions of the subsystems, and finally elaborated on the approaches and steps of building a mathematics model for the analysis of dynamic hydraulic status.
基金supported by the National Natural Science Foundation of China(No.22175125)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.21KJA150008)the Key Laboratory of Polymeric Materials De-sign and Synthesis for Biomedical Function,Soochow University,and the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Bacterial biofilms,especially those caused by multidrug-resistant bacteria,have emerged as one of the greatest dangers to global public health.The acceleration of antimicrobial resistance to conventional an-tibiotics and the severe lack of new drugs necessitates the development of novel agents for biofilm eradication.Photodynamic therapy(PDT)is a promising non-antibiotic method for treating bacterial infections.However,its application in biofilm eradication is hampered by the hypoxic microenvironment of biofilms and the physical protection of extracellular polymeric substances.In this study,we develop a composite nanoplatform with oxygen(O_(2))self-supplying and heat-sensitizing capabilities to improve the PDT efficacy against biofilms.CaO_(2)/ICG@PDA nanoparticles(CIP NPs)are fabricated by combining calcium peroxide(CaO_(2))with the photosensitizer indocyanine green(ICG)via electrostatic interactions,followed by coating with polydopamine(PDA).The CIP NPs can gradually generate O_(2)in response to the acidic microenvironment of the biofilm,thereby alleviating its hypoxic state.Under near-infrared(NIR)irradiation,the nanoplatform converts O_(2)into a significant amount of singlet oxygen(^(1)O_(2))and heat to eradicate biofilm.The generated heat enhances the release of O_(2),accelerates the generation of^(1)O_(2)in PDT,increases cell membrane permeability,and increases bacterial sensitivity to^(1)O_(2).This nanoplatform significantly improves the efficacy of PDT in eradicating biofilm-dwelling bacteria without fostering drug resistance.Experiments on biofilm eradication demonstrate that this nanoplatform can eradicate over 99.9999%of methicillin-resistant Staphylococcus aureus(MRSA)biofilms under 5-min NIR irradiation.Notably,these integrated advantages enable the system to promote the healing of MRSA biofilm-infected wounds with negligible toxicity in vivo,indicating great promise for overcoming the obstacles associated with bacterial biofilm eradication.
基金supported by National Natural Science Funds(52078308)Liao Ning Revitalization Talents Program(XLYC2007003)the Educational Commission of Liaoning Province of China(lnzd202003).
文摘The building sector is one of the largest energy user and carbon emitters globally.To increase the utilization rate of renewable energy and reduce carbon dioxide emissions,the optimal technical scheme of active public institutions and coupled utilization of renewable energy is studied.In this study,the energy consumption of three types of public institutions in various regions of China was simulated by using DeST building energy consumption software,combined with energy conversion efficiency and data released by the National Bureau of Statistics,and the total energy demand and total energy supply of public institutions were predicted using the load density method.Based on the coupling mechanism of the MARKAL model,the optimal proportion of renewable energy in the energy supply of public buildings in different regions is determined.Through the study of the number of public institutions in various regions of China,energy consumption characteristics,construction area,and other related data,the reverse energy flow method is creatively proposed,and the active and renewable energy coupling algorithm from the energy demand side of public institutions to the energy supply side is established.The results show that the central region has the highest utilization rate of renewable energy in the public sector,reaching 36.18%.The use of renewable energy in public buildings in hot summer and warm winter zones decreased to 35.08%,and it was 12.82% in cold zones.By 2025,the proportion of renewable energy resources in China is expected to reach 29.2%.The energy coupling model and algorithm constructed in this paper can provide a basis for the coupling macro configuration of renewable energy in public institutions in China.
基金supported by the National Natural Science Foundation of China(Grant No.51806234)。
文摘The liquid nitrogen(LN2)supplying system,one of the four key systems of the cryogenic wind tunnel(CWT),is an essential guarantee for the precise control,fast and safe regulation of the wind tunnel’s total temperature.Firstly,the technical schemes,advantages and disadvantages of different LN2 supplying systems are discussed and analyzed based on the operation conditions and test requirements of different CWTs.Then,together with the development of the pilot cryogenic transonic wind tunnel(PCTW),the key technologies of the system,including the supplying mode,rapid and accurate regulation of injection pressure,development of large scale cryogenic centrifugal pump,and matching technology between pumps and pipe network,have been summarized and the solutions to the existing issues are given.Finally,a supplying process suitable for large-scale CWT is proposed,which has the ability of independent commissioning,rapid regulation,accurate control of injection pressure and transient response to the wind tunnel’s wide range of working conditions.The breakthrough in LN2 supplying system enables China to construct a CWT for the future competitive high Reynolds number aircraft.
基金Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration under Grant Nos.2021EEEVL0204 and 2018A02。
文摘As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete(RC)frame structure.Different material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic performance.Floor response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions.A seismic fragility study of displacement demand is conducted based on numerical simulation.The acceleration response and displacement response of different combinations are compared.The results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes.
基金supported in part by the Scientific Foundation for Outstanding Young Scientists of Sichuan under Grant No.2021JDJQ0032in part by the National Natural Science Foundation of China under Grant No.52107128in part by the Natural Science Foundation of Sichuan Province under Grant No.2022NSFSC0436.
文摘Traction power systems(TPSs)play a vital role in the operation of electrified railways.The transformation of conventional railway TPSs to novel structures is not only a trend to promote the development of electrified railways toward high-efficiency and resilience but also an inevitable requirement to achieve carbon neutrality target.On the basis of sorting out the power supply structures of conventional AC and DC modes,this paper first reviews the characteristics of the existing TPSs,such as weak power supply flexibility and low-energy efficiency.Furthermore,the power supply structures of various TPSs for future electrified railways are described in detail,which satisfy longer distance,low-carbon,high-efficiency,high-reliability and high-quality power supply requirements.Meanwhile,the application prospects of different traction modes are discussed from both technical and economic aspects.Eventually,this paper introduces the research progress of mixed-system electrified railways and traction power supply technologies without catenary system,speculates on the future development trends and challenges of TPSs and predicts that TPSs will be based on the continuous power supply mode,employing power electronic equipment and intelligent information technology to construct a railway comprehensive energy system with renewable energy.
基金funded by the China National Key Research and Development Program(No.2022YFC3003505)the Fundamental Research Fund for the Central Public-interest Scientific Institutes(No.DQJB23Y01)+1 种基金the National Natural Science Foundation of China(No.52278540)the Fundamental Research Fund for the Central Public-interest Scientific Institutes(No.DQJB22B28).
文摘In 2023,two consecutive earthquakes exceeding a magnitude of 7 occurred in Türkiye,causing severe casualties and economic losses.The damage to critical urban infrastructure and building structures,including highways,railroads,and water supply pipelines,was particularly severe in areas where these structures intersected the seismogenic fault.Critical infrastructure projects that traverse active faults are susceptible to the influence of fault movement,pulse velocity,and ground motions.In this study,we used a unique approach to analyze the acceleration records obtained from the seismic station array(9 strong ground motion stations)located along the East Anatolian Fault(the seismogenic fault of the MW7.8 mainshock of the 2023 Türkiye earthquake doublet).The acceleration records were filtered and integrated to obtain the velocity and displacement time histories.We used the results of an on-site investigation,jointly conducted by China Earthquake Administration and Türkiye’s AFAD,to analyze the distribution of PGA,PGV,and PGD recorded by the strong motion array of the East Anatolian Fault.We found that the maximum horizontal PGA in this earthquake was 3.0 g,and the maximum co-seismic surface displacement caused by the East Anatolian Fault rupture was 6.50 m.As the fault rupture propagated southwest,the velocity pulse caused by the directional effect of the rupture increased gradually,with the maximum PGA reaching 162.3 cm/s.We also discussed the seismic safety of critical infrastructure projects traversing active faults,using two case studies of water supply pipelines in Türkiye that were damaged by earthquakes.We used a three-dimensional finite element model of the PE(polyethylene)water pipeline at the Islahiye State Hospital and fault displacement observations obtained through on-site investigation to analyze pipeline failure mechanisms.We further investigated the effect of the fault-crossing angle on seismic safety of a pipeline,based on our analysis and the failure performance of the large-diameter Thames Water pipeline during the 1999 Kocaeli earthquake.The seismic method of buried pipelines crossing the fault was summarized.
基金Item Sponsored by National Natural Science Foundation of China(51204041)National High Technology Research and Development Program(863 Program) of China(2012AA03A502)+1 种基金Fundamental Research Funds for the Central Universities of China(N130402016)Program for Liaoning's Innovative Research Team in University of China(LT20120008)
文摘With ificreasing demand for large cylindrical forgings, a new technology--electroslag remelting (ESR) for direct manufacture of hollow ingots rather than solid ingots has been developed. The main features of the process include a T-shaped current supplying mould (CSM), double power supply, an ingot withdrawing system, a metal level automatic control system based on a level sensor using the electromagnetic eddy current method, and the exchange of a consumable multi-electrode. ANSYS software was used to calculate the fluid flow and heat transfer in the slag bath 1 and metal pool of this ESR hollow ingot process with its T-shaped CSM. The mathematmal model was Verified by measuring the geometry of the liquid metal pool as observed in the macrostructure of 4650 mm (external diameter)/ 4450 mm (internal diameter) hollow ingots by sulphur print method: the. observed shape and depth of the s!ag bath were consistent with the simulated results. Simulation of the ESR process can improve understanding of the process and allow better operating parameters to be selected.
基金supported by the JSPS KAKENHI(Grant numbers JP20H00288 and JP22K02136)
文摘Wearable triboelectric nanogenerators(TENGs)have attracted attention owing to their ability to harvest energy from the surrounding environment without maintenance.Herein,polyetherimide-Al_(2)O_(3)(PAl)and polyvinylidene fluoride-co-hexafluoropropylene(PVDF-HFP,PH)nanofiber membranes were used as tribo-positive and tribo-negative materials,respectively.Phytic acid-doped polyaniline(PANI)/cotton fabric(PPCF)and ethylenediamine(EDA)-crosslinked PAl(EPAl)nanofiber membranes were used as triboelectrode and triboencapsulation materials,respectively.The result showed that when the PAl-PH-based TENG was shaped as a circle with a radius of 1 cm,under the pressure of 50 N,and the frequency of 0.5 Hz,the open-circuit voltage(V_(oc))and short-circuit current(I_(sc))reached the highest value of 66.6 V and-93.4 to 110.1 nA,respectively.Moreover,the PH-based TENG could be used as a fabric sensor to detect fabric composition and as a sensor-inductive switch for light bulbs or beeping warning devices.When the PAl-PH-based TENG was shaped as a 5×5 cm^(2)rectangle,a 33 pF capacitor could be charged to 15 V in 28 s.Interestingly,compared to PAl nanofiber membranes,EPAl nanofiber membranes exhibited good dyeing properties and excellent solvent resistance.The PPCF exhibited<5%resistance change after washing,bending,and stretching.