Objective:To establish a scientific,objective and applicable index system for evaluating out- standing biomedical scientists for science foundation of Shanghai.Methods:According to the principal in- dices that have be...Objective:To establish a scientific,objective and applicable index system for evaluating out- standing biomedical scientists for science foundation of Shanghai.Methods:According to the principal in- dices that have been used in the developed countries for evaluating their talented personnel and the reality of our country,an index system was set up to evaluate the outstanding biomedical scientists for Shanghai science foundation.The following parameters were used to simplify the indices.,correlation coefficient, multiple correlation coefficient,partial correlation coefficient,creditability,and discriminatory power. And analytic hierarchy process was used to determine the weights of each index.Results and Conclusions: The established index system is scientific and applicable;it is helpful for cultivating and evaluating out- standing biomedical scientists.展开更多
Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,pr...Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,providing novel insights into species evolution mechanisms and conservation management in the Anthropocene.The Eastern Golden Frog(Pelophylax plancyi)and BlackSpotted Frog(P.nigromaculatus)are two sympatric anuran species with a long history of mitochondrial genome introgression in highly urbanized continental East Asia.However,there is only limited understanding of the pattern of their contemporary hybridization and factors influencing their interspecific relationship under anthropogenic disturbances.Here,interspecific hybridization between P.plancyi and P.nigromaculatus at the population level was investigated in Shanghai.All except two haplotypes obtained from both species in Shanghai were mixed together,and located in the introgression clade,implying multiple ancient mitochondrial introgression events occurred in the populations of our study area.Asymmetric genetic introgression was detected by microsatellite markers,with 0.7%of P.plancyi and 14.6%of P.nigromaculatus identified as contemporary admixed individuals.Consistent with the trend of population density,higher genetic diversity of neutral microsatellite loci was found in the more abundant P.plancyi;however,variation in mitochondrial(Cyt-b)and nuclear(POMC)genes was higher in relatively rare P.nigromaculatus.The population density of P.plancyi and number of water patches within local habitats were significantly positively correlated with both occurrences and proportions of admixed individuals in the populations of P.plancyi and P.nigromaculatus.Considering the prevalent transformation of habitats in urbanized areas,these results imply that a high population density in isolated artificially altered habitats is likely to increase interspecific hybridization.Thus,population monitoring and improvement of landscape connectivity between habitats would be needed to control the intensity of interspecific hybridization between P.plancyi and P.nigromaculatus in anthropogenic-disturbed environments.展开更多
With the tremendous advances in the field of information and communications technology(ICT),and the emergence of new applications,such as 4K/8K,AR/VR,Internet of Things,and Industrial Internet and so on,the traditiona...With the tremendous advances in the field of information and communications technology(ICT),and the emergence of new applications,such as 4K/8K,AR/VR,Internet of Things,and Industrial Internet and so on,the traditional Internet has faced severe challenges on scalability,flexibility,controllability,mobility and security and so on.In order to cope with these challeng-展开更多
At transformation stage,seed Industry is not only a fundamental and strategic industry during the construction of World City,but also part of urban and modern agriculture in Beijing. Based on the analysis of the theor...At transformation stage,seed Industry is not only a fundamental and strategic industry during the construction of World City,but also part of urban and modern agriculture in Beijing. Based on the analysis of the theory of industrial economics and system theory,the article constructs the seed industry policy analysis model,systematically analyzes the support points of national level and the city of Beijing seed industry policy,and studies policy input,mechanism,output and effects by way of systematic analysis,as well as proposes polices and suggestions on promotion of development for Beijing seed industry and on construction of new seed industry from talent incentive,platform construction,seed trading and enterprise cultivation.展开更多
A novel and efficient method for decomposing a signal into a set of intrinsic mode functions （IMFs） and a trend is proposed. Unlike the original empirical mode decomposition （EMD）, which uses spline fits to extrac...A novel and efficient method for decomposing a signal into a set of intrinsic mode functions （IMFs） and a trend is proposed. Unlike the original empirical mode decomposition （EMD）, which uses spline fits to extract variations from the signal by separating the local mean from the fluctuations in the decomposing process, this new method being proposed takes advantage of the theory of variable finite impulse response （FIR） filtering where filter coefficients and breakpoint frequencies can be adjusted to track any peak-to-peak time scale changes. The IMFs are results of a multiple variable frequency response FIR filtering when signals pass through the filters. Numerical examples validate that in contrast with the original EMD, the proposed method can fine-tune the frequency resolution and suppress the aliasing effectively.展开更多
There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial gro...There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial growth in many aquatic ecosystems, there are, however, many water sources that are limited by phosphorus or nitrogen. A method named ＂nitrogen fixing bacterial growth potential＂ （NFBGP） test, which is based on pre-culturing of autochthonous （target） microorganisms was described. The method was applied to evaluate phosphorus or nitrogen nutrient limitation in lake and sewage water samples using an isolate of the nitrogen fixing bacterium, Azorhizobium sp. WS6. The results corresponded well to those from the traditional algal growth potential （AGP） test and the bacterial regrowth potential （BRP） test, suggesting that the NFBGP test is a useful supplementary method for evaluating the limiting nutrient, especially phosphorus, in an aquatic environment.展开更多
Multi-fidelity simulations incorporate computational fluid dynamics(CFD) models into a thermodynamic model,enabling the simulation of the overall performance of an entire gas turbine with high-fidelity components.Trad...Multi-fidelity simulations incorporate computational fluid dynamics(CFD) models into a thermodynamic model,enabling the simulation of the overall performance of an entire gas turbine with high-fidelity components.Traditional iterative coupled methods rely on characteristic maps,while fully coupled methods directly incorporate high-fidelity simulations.However,fully coupled methods face challenges in simulating rotating components,including weak convergence and complex implementation.To address these challenges,a fully coupled method with logarithmic transformations was developed to directly integrate high-fidelity CFD models of multiple rotating components.The developed fully coupled method was then applied to evaluate the overall performance of a KJ66 micro gas turbine across various off-design simulations.The developed fully coupled method was also compared with the traditional iterative coupled method.Furthermore,experimental data from ground tests were conducted to verify its effectiveness.The convergence history indicated that the proposed fully coupled method exhibited stable convergence,even under far-off-design simulations.The experimental verification demonstrated that the multi-fidelity simulation with the fully coupled method achieved high accuracy in off-design conditions.Further analysis revealed inherent differences in the coupling methods of CFD models between the developed fully coupled and traditional iterative coupled methods.These inherent differences provide valuable insights for reducing errors between the component-level model and CFD models in different coupling methods.The developed fully coupled method,introducing logarithmic transformations,offers more realistic support for the detailed and optimal design of high-fidelity rotating components within the overall performance platform of gas turbines.展开更多
Background： Although coronary heart disease （CHD） is one of the major cardiovascular diseases, risk factors associated with the health-related quality of life （HRQoL） of CHD patients remain unclear. The present s...Background： Although coronary heart disease （CHD） is one of the major cardiovascular diseases, risk factors associated with the health-related quality of life （HRQoL） of CHD patients remain unclear. The present study was designed to determine the profile and significant factors of the HRQoL in CHD patients.Methods： A cross-sectional study was conducted in rural communities of Fangshan District, Beijing. China. Socio-demographic, lifestyle, and comorbidity information of CHD patients were collected by a structured questionnaire and medical records. HRQoL was measured using European Quality of Life 5-dimensions （EQ-5D） scale and EQ Visual Analog Scale （EQ-VAS）. Multiple linear and logistic regressions were performed to explore the association of potential risk factors with HRQoL scores and each EQ-SD, respectively.Results： Totally, 1928 CHD patients （mean age 61.64 ± 9.24 years; female：male = 2.4：1） were enrolled in the study. The mean score of EQ-5D index and EQ-VAS were 0.889 ±0.172 and 71.56 ±17.65, respectively. Multiple linear regression revealed that marital status, physical activity, moderate alcohol drinking, and family＇s population were positive independent correlates of EQ-VAS, whereas diabetes mellitus and stroke were negative independent correlates （all P 〈 0.05）. Age and stroke were negatively while physical activity, moderate alcohol drinking, family＇s population and household income were positively correlated with EQ-5D index （all P 〈 0.05） independently. In addition, each of the five HRQoL dimensions had various specific determinants, including obesity, underweight. smoking or education. Conclusions： Findings of the study highlight certain socio-demographic, lifestyle factors, and comorbid stroke or diabetes mellitus as correlates of HRQoL in Chinese CHD patients. Large-scale cohort studies should be carried out to confirm our results in the future.展开更多
Nitrate(NO_(3)^(−))accumulation in recirculating aquaculture systems(RASs)with high stocking densities presents a problem for reared animals and the environment.The use of a biodegradable polymer as organic carbon for...Nitrate(NO_(3)^(−))accumulation in recirculating aquaculture systems(RASs)with high stocking densities presents a problem for reared animals and the environment.The use of a biodegradable polymer as organic carbon for heterotrophic denitrification exhibits good performance for NO_(3)^(−)removal from wastewater.A comparison of NO_(3)^(−)–N removal efficiency and bacterial properties using polycaprolactone(PCL)and poly(3-hydroxybutyrateco-3-hydroxyvalerate)(PHBV)as carbon sources to treat aquaculture water was conducted for a 102-day period.The results indicated that the NO_(3)^(−)–N removal rates of 0.27±0.07 and 0.19±0.05 g/L per day,respectively,could be achieved with influent concentrations ranging from 81.1 to 132.75 mg/L and a flow rate of 1 L/h.The removal of NO_(3)^(−)–N versus consumed PCL(1:1 w/w)was significantly higher than that versus consumed PHBV(0.3:1 w/w)(P<0.05).The concentrations of effluent nitrite-nitrogen and total ammonium nitrogen were maintained at an acceptable level.The bacterial community structures between the two types of reactors varied significantly.Acidovorax and Denitratisoma were the top two genera of the bacterial community in the biofilm in the PCL beads with a dominance of 26.83%and 6.67%,respectively.In the PHBV beads,Acidovorax at 17.95%and Bdellovibrio at 6.37%were the top two genera.The PCL-denitrification reactor developed in this study showed better potential than the PHBV-denitrification reactor in removing NO_(3)^(−)from aquaculture water.展开更多
The aquaculture of yellowtail kingfish(Seriola lalandi)has expanded around the globe,including China.Genetic resource of Chinese S.lalandi urgently needs to be assessed for improving production.Here,we collected wild ...The aquaculture of yellowtail kingfish(Seriola lalandi)has expanded around the globe,including China.Genetic resource of Chinese S.lalandi urgently needs to be assessed for improving production.Here,we collected wild S.lalandi samples from the Bohai Sea,China and evaluated its genetic diversity based on 17,690 nuclear loci.A population from the Southern Ocean,Australia was used for comparison.The analyses showed that the Chinese and Australian S.lalandi formed two completely distinct clusters and there was no genetic introgression from the Australian S.lalandi into the Chinese S.lalandi population.The genetic diversity is slightly lower,but comparable in Chinese versus Australian yellowtail kingfish(Chinese population,expected heterozygosity:0.19,observed heterozygosity:0.19,nucleotide diversity:0.19±0.09;Australian population,expected heterozygosity:0.23,observed heterozygosity:0.22,nucleotide diversity:0.22±0.11).Overall,our results indicated that Chinese S.lalandi could be a potential subject for genetic breeding programs.We also investigated morphological characters and developed molecular markers for population identification.Comparison of meristic characters between the Chinese population and the Australian population revealed that main shape difference were in the number of dorsal spines,dorsal fin rays and the number of upper gill rakers.Geometric morphology based on eight landmarks also revealed significant difference between the two populations including the distance between the tip of snout to origin of pelvic fin and the distance between the tip of snout to origin of pectoral fin.These morphological characters can be used for easy identification of the Chinese S.lalandi.展开更多
Iterative coupled methods are widely used in multi-fidelity simulation of rotating components due to the simple implementation,which iteratively eliminates the errors between the computational fluid dynamics models an...Iterative coupled methods are widely used in multi-fidelity simulation of rotating components due to the simple implementation,which iteratively eliminates the errors between the computational fluid dynamics models and approximate characteristic maps.However,the convergence and accuracy of the iterative coupled method are trapped in characteristic maps.In particular,iterative steps increase sharply as the operation point moves away from the design point.To address these problems,this paper developed an auxiliary iterative coupled method that introduces the static-pressure-auxiliary characteristic maps and modification factor of mass flow into the component-level model.The developed auxiliary method realized the direct transfer of static pressure between the high-fidelity models and the component-level model.Multi-fidelity simulations of the throttle characteristics were carried out using both the auxiliary and traditional iterative coupled methods,and the simulation results were verified using the experimental data.Additionally,the consistency between the auxiliary and traditional iterative coupled methods was confirmed.Subsequently,multi-fidelity simulations of the speed and altitude characteristics were also conducted.The auxiliary and traditional iterative coupled methods were evaluated in terms of convergence speed and accuracy.The evaluation indicated that the auxiliary iterative coupled method significantly reduces iterative steps by approximately 50%at the near-choked state.In general,the auxiliary iterative coupled method is preferred as a development of the traditional iterative coupled method in the near-choked state,and the combined auxiliary-traditional iterative coupled method provides support for successful multi-fidelity simulation in far-off-design conditions.展开更多
Introduction The 2021 Annual Conference of the Housing and Community Planning Committee of the Urban Planning Society of China(UPSC)was successfully held in Beijing on Jun.5,2021.Under the guidance of the UPSC,the con...Introduction The 2021 Annual Conference of the Housing and Community Planning Committee of the Urban Planning Society of China(UPSC)was successfully held in Beijing on Jun.5,2021.Under the guidance of the UPSC,the conference was hosted by the Housing and Community Planning Committee of the UPSC,and jointly supported by the Beijing Tsinghua Tongheng Urban Planning&Design Institute and the Specialized Committee of Community Building,Science and Technology Committee,Ministry of Housing and Urban-Rural Development.展开更多
Disturbed state concept(DSC) theory maintains that the observed actual response(AR) of material under loading effects is composed of and determined by two reference state responses,namely relative intact(RI) state res...Disturbed state concept(DSC) theory maintains that the observed actual response(AR) of material under loading effects is composed of and determined by two reference state responses,namely relative intact(RI) state response and fully adjusted(FA) state response. Hardening material shows macroscopic behavior characteristics of RI response and shows negligible mesoscopic structure changes. Pore water pressure dissipation in macroscopic experiment or variance of computerized tomography(CT) value in mesoscopic experiment,as chosen characteristic parameters,can be introduced to the evolution function of disturbance factor to revise response of hardening to be response of softening. RI behavior is constituted via using hardening model. The characteristic parameters are extracted from regulations which exist in macroscopic or mesoscopic experimental data of softening material. DSC approach strategy on response prediction is presented through the combination of characteristic parameters and hardening constitutive model within the procedure of softening response prediction.展开更多
In recirculating aquaculture systems,nitrification is usually accelerated by inoculating nitrifier or mature biocarriers.In this study,the performance of the establishment of nitrification in the MBBR according to thr...In recirculating aquaculture systems,nitrification is usually accelerated by inoculating nitrifier or mature biocarriers.In this study,the performance of the establishment of nitrification in the MBBR according to three different strategies:conventional method(Control group A),inoculation with biofloc recovered from a tilapia biofloc culture system(Group B),and addition with extra nitrite(Group C)in the Moving bed biofilm reactor(MBBR)was compared.Among them,the biofloc-inoculated group considerably accelerated the nitrification process in the MBBR(38 d),which is roughly 18 d faster than the control group(A)(56 d)and 21 d faster than group C(59 d).Less ammonia(8 mg/L NH_(4)^(+)-N,10 mg/L in other groups)and external nitrite(2 mg/L NO_(2)^(-)N)in the influent caused effluent ammonia to drop more slowly(5 d slower than the control group,8 d slower than the B group),which is detrimental to the nitrification process’development.Notably,the influent’s hydraulic retention time(HRT)was reduced from 12 h to 6 h following the successful establishment of nitrification.During the adaptation to reduced HRT,the MBBR inoculated with biofloc experienced short-term changes in the water quality index of the effluent water,whereas the other groups did not.The biofilm seeded with biofloc had the highest mean gray value ratio(1.42)of live/dead cell fluorescence,which grew better and could cover the entire groove under multiple microscope observations.However,the other groups did not demonstrate a similar trend.In summary,the research found that seeding biofloc use as nitrification bioaugmentation into the MBBR of the recirculating aquaculture system(RAS)to greatly speed up the nitrification process.展开更多
To solve the receding horizon control （RHC） problem in an online manner, a novel numerical method called the indirect Radau pseudospectral method （IRPM） is proposed in this paper. Based on calculus of variations a...To solve the receding horizon control （RHC） problem in an online manner, a novel numerical method called the indirect Radau pseudospectral method （IRPM） is proposed in this paper. Based on calculus of variations and the first-order necessary optimality condition, the RHC problem for linear time-varying （LTV） system is transformed into the two-point boundary value problem （TPBVP）. The Radau pseudospectral approximation is employed to discretize the TPBVP into well-posed linear algebraic equations. The resulting linear algebraic equations are solved via a matrix partitioning approach afterwards to obtain the optimal feedback control law. For the nonlinear system, the linearization method or the quasi linearization method is employed to approximate the RHC problem with successive linear approximations. Subsequently, each linear problem is solved via the similar method which is used to solve the RHC problem for LTV system. Simulation results of three examples show that the IRPM is of high accuracy and of high compu- tation efficiency to solve the RHC problem and the stability of closed-loop systems is guaranteed.展开更多
The conventional re-entry guidance method considerably limits the maneuverability of hypersonic glide vehicles under pre-given angle-of-attack profiles.To address this issue,based on a previous three-dimensional(3D)pr...The conventional re-entry guidance method considerably limits the maneuverability of hypersonic glide vehicles under pre-given angle-of-attack profiles.To address this issue,based on a previous three-dimensional(3D)profile guidance method,we propose a lateral-profile-first 3D profile optimization design strategy to solve the trajectory generation problem under complex conditions involving multiple constraints.Unlike the traditional method,which prioritizes the design of the longitudinal drag acceleration profiles,our method first converted the re-entry flight constraints into a lateral flight corridor,generated the initial lateral profile via parameterization,and solved the 3D profile using the coupling relationship between the longitudinal and lateral motions.The design of the 3D profile requires simultaneous consideration of waypoints,no-fly zones,and altitude profiles;hence,a new 3D profile optimization design model was constructed,and a customized sequential quadratic programming algorithm was employed to solve it.The advantages of the proposed method were demonstrated based on landing footprint results obtained using the lateral profile-first strategy.Finally,simulation results based on the common aero vehicle-high-performance model verified the feasibility and effectiveness of the strategy.展开更多
This paper describes how Chinese companies can enhance their competitive advantage through implementing enterprise information systems （EIS）. The reference framework combines strategic information system alignment a...This paper describes how Chinese companies can enhance their competitive advantage through implementing enterprise information systems （EIS）. The reference framework combines strategic information system alignment and dynamic capabilities perspectives. EIS implementations were analyzed in eight companies （four in China and four in Europe）. Recommendations derived from this analysis can be used by Chinese EIS practitioners to effectively enhance organizational competitiveness through EIS implementation. The results show that Chinese companies must achieve a strategic alignment between their business strat- egy and EIS strategy and then they should facilitate EIS implementation by effectively designing managerial processes and learning mechanisms.展开更多
文摘Objective:To establish a scientific,objective and applicable index system for evaluating out- standing biomedical scientists for science foundation of Shanghai.Methods:According to the principal in- dices that have been used in the developed countries for evaluating their talented personnel and the reality of our country,an index system was set up to evaluate the outstanding biomedical scientists for Shanghai science foundation.The following parameters were used to simplify the indices.,correlation coefficient, multiple correlation coefficient,partial correlation coefficient,creditability,and discriminatory power. And analytic hierarchy process was used to determine the weights of each index.Results and Conclusions: The established index system is scientific and applicable;it is helpful for cultivating and evaluating out- standing biomedical scientists.
基金supported by the National Natural Science Foundation of China(32071529)the Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station(Z202204)+1 种基金Shanghai Key Lab for Urban Ecological Processes and EcoRestoration(SHUES2020B06,SHUES2021C04)the Fundamental Research Funds for the Central Universities.
文摘Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,providing novel insights into species evolution mechanisms and conservation management in the Anthropocene.The Eastern Golden Frog(Pelophylax plancyi)and BlackSpotted Frog(P.nigromaculatus)are two sympatric anuran species with a long history of mitochondrial genome introgression in highly urbanized continental East Asia.However,there is only limited understanding of the pattern of their contemporary hybridization and factors influencing their interspecific relationship under anthropogenic disturbances.Here,interspecific hybridization between P.plancyi and P.nigromaculatus at the population level was investigated in Shanghai.All except two haplotypes obtained from both species in Shanghai were mixed together,and located in the introgression clade,implying multiple ancient mitochondrial introgression events occurred in the populations of our study area.Asymmetric genetic introgression was detected by microsatellite markers,with 0.7%of P.plancyi and 14.6%of P.nigromaculatus identified as contemporary admixed individuals.Consistent with the trend of population density,higher genetic diversity of neutral microsatellite loci was found in the more abundant P.plancyi;however,variation in mitochondrial(Cyt-b)and nuclear(POMC)genes was higher in relatively rare P.nigromaculatus.The population density of P.plancyi and number of water patches within local habitats were significantly positively correlated with both occurrences and proportions of admixed individuals in the populations of P.plancyi and P.nigromaculatus.Considering the prevalent transformation of habitats in urbanized areas,these results imply that a high population density in isolated artificially altered habitats is likely to increase interspecific hybridization.Thus,population monitoring and improvement of landscape connectivity between habitats would be needed to control the intensity of interspecific hybridization between P.plancyi and P.nigromaculatus in anthropogenic-disturbed environments.
文摘With the tremendous advances in the field of information and communications technology(ICT),and the emergence of new applications,such as 4K/8K,AR/VR,Internet of Things,and Industrial Internet and so on,the traditional Internet has faced severe challenges on scalability,flexibility,controllability,mobility and security and so on.In order to cope with these challeng-
基金Supported by Project of Beijing Municipal Science and Technology Plan(Z121100001512002)Project of Beijing Municipal Science And Technology Plan(Z111100054011074)+2 种基金Special Research Project of Strategic Research and Expert Consulting of Science and Technology Innovation of Beijing Municipal Science&Technology Commission(Z151100003115072)Special Project of Soft Science Research of Beijing Municipal Science&Technology Commission(Z121108002212039)The Collaborative Project of Scientific Research and Graduate Training of Beijing Municipal Education Commission(201502911110426)
文摘At transformation stage,seed Industry is not only a fundamental and strategic industry during the construction of World City,but also part of urban and modern agriculture in Beijing. Based on the analysis of the theory of industrial economics and system theory,the article constructs the seed industry policy analysis model,systematically analyzes the support points of national level and the city of Beijing seed industry policy,and studies policy input,mechanism,output and effects by way of systematic analysis,as well as proposes polices and suggestions on promotion of development for Beijing seed industry and on construction of new seed industry from talent incentive,platform construction,seed trading and enterprise cultivation.
基金supported by the National Natural Science Foundation of China (60472021).
文摘A novel and efficient method for decomposing a signal into a set of intrinsic mode functions （IMFs） and a trend is proposed. Unlike the original empirical mode decomposition （EMD）, which uses spline fits to extract variations from the signal by separating the local mean from the fluctuations in the decomposing process, this new method being proposed takes advantage of the theory of variable finite impulse response （FIR） filtering where filter coefficients and breakpoint frequencies can be adjusted to track any peak-to-peak time scale changes. The IMFs are results of a multiple variable frequency response FIR filtering when signals pass through the filters. Numerical examples validate that in contrast with the original EMD, the proposed method can fine-tune the frequency resolution and suppress the aliasing effectively.
基金The Natural Science Foundation of Zhejiang Province, China(No. M303106)
文摘There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial growth in many aquatic ecosystems, there are, however, many water sources that are limited by phosphorus or nitrogen. A method named ＂nitrogen fixing bacterial growth potential＂ （NFBGP） test, which is based on pre-culturing of autochthonous （target） microorganisms was described. The method was applied to evaluate phosphorus or nitrogen nutrient limitation in lake and sewage water samples using an isolate of the nitrogen fixing bacterium, Azorhizobium sp. WS6. The results corresponded well to those from the traditional algal growth potential （AGP） test and the bacterial regrowth potential （BRP） test, suggesting that the NFBGP test is a useful supplementary method for evaluating the limiting nutrient, especially phosphorus, in an aquatic environment.
基金funded by the Science and Technology Innovation Committee Foundation of Shenzhen,Grant No.JCYJ20200109141403840 and Grant No.ZDSYS20220527171405012the National Natural Science Foundation of China (NSFC),Grant No.52106045。
文摘Multi-fidelity simulations incorporate computational fluid dynamics(CFD) models into a thermodynamic model,enabling the simulation of the overall performance of an entire gas turbine with high-fidelity components.Traditional iterative coupled methods rely on characteristic maps,while fully coupled methods directly incorporate high-fidelity simulations.However,fully coupled methods face challenges in simulating rotating components,including weak convergence and complex implementation.To address these challenges,a fully coupled method with logarithmic transformations was developed to directly integrate high-fidelity CFD models of multiple rotating components.The developed fully coupled method was then applied to evaluate the overall performance of a KJ66 micro gas turbine across various off-design simulations.The developed fully coupled method was also compared with the traditional iterative coupled method.Furthermore,experimental data from ground tests were conducted to verify its effectiveness.The convergence history indicated that the proposed fully coupled method exhibited stable convergence,even under far-off-design simulations.The experimental verification demonstrated that the multi-fidelity simulation with the fully coupled method achieved high accuracy in off-design conditions.Further analysis revealed inherent differences in the coupling methods of CFD models between the developed fully coupled and traditional iterative coupled methods.These inherent differences provide valuable insights for reducing errors between the component-level model and CFD models in different coupling methods.The developed fully coupled method,introducing logarithmic transformations,offers more realistic support for the detailed and optimal design of high-fidelity rotating components within the overall performance platform of gas turbines.
基金Source of Support： This work was supported by grants from the National Natural Science Foundation of China （No. 81230066, No. 30872173, No. 81172744）. Conflict of Interest： None declared.
文摘Background： Although coronary heart disease （CHD） is one of the major cardiovascular diseases, risk factors associated with the health-related quality of life （HRQoL） of CHD patients remain unclear. The present study was designed to determine the profile and significant factors of the HRQoL in CHD patients.Methods： A cross-sectional study was conducted in rural communities of Fangshan District, Beijing. China. Socio-demographic, lifestyle, and comorbidity information of CHD patients were collected by a structured questionnaire and medical records. HRQoL was measured using European Quality of Life 5-dimensions （EQ-5D） scale and EQ Visual Analog Scale （EQ-VAS）. Multiple linear and logistic regressions were performed to explore the association of potential risk factors with HRQoL scores and each EQ-SD, respectively.Results： Totally, 1928 CHD patients （mean age 61.64 ± 9.24 years; female：male = 2.4：1） were enrolled in the study. The mean score of EQ-5D index and EQ-VAS were 0.889 ±0.172 and 71.56 ±17.65, respectively. Multiple linear regression revealed that marital status, physical activity, moderate alcohol drinking, and family＇s population were positive independent correlates of EQ-VAS, whereas diabetes mellitus and stroke were negative independent correlates （all P 〈 0.05）. Age and stroke were negatively while physical activity, moderate alcohol drinking, family＇s population and household income were positively correlated with EQ-5D index （all P 〈 0.05） independently. In addition, each of the five HRQoL dimensions had various specific determinants, including obesity, underweight. smoking or education. Conclusions： Findings of the study highlight certain socio-demographic, lifestyle factors, and comorbid stroke or diabetes mellitus as correlates of HRQoL in Chinese CHD patients. Large-scale cohort studies should be carried out to confirm our results in the future.
基金funded by the Shanghai Science and Technology Commission(Shanghai,China)Project(16DZ2281200).
文摘Nitrate(NO_(3)^(−))accumulation in recirculating aquaculture systems(RASs)with high stocking densities presents a problem for reared animals and the environment.The use of a biodegradable polymer as organic carbon for heterotrophic denitrification exhibits good performance for NO_(3)^(−)removal from wastewater.A comparison of NO_(3)^(−)–N removal efficiency and bacterial properties using polycaprolactone(PCL)and poly(3-hydroxybutyrateco-3-hydroxyvalerate)(PHBV)as carbon sources to treat aquaculture water was conducted for a 102-day period.The results indicated that the NO_(3)^(−)–N removal rates of 0.27±0.07 and 0.19±0.05 g/L per day,respectively,could be achieved with influent concentrations ranging from 81.1 to 132.75 mg/L and a flow rate of 1 L/h.The removal of NO_(3)^(−)–N versus consumed PCL(1:1 w/w)was significantly higher than that versus consumed PHBV(0.3:1 w/w)(P<0.05).The concentrations of effluent nitrite-nitrogen and total ammonium nitrogen were maintained at an acceptable level.The bacterial community structures between the two types of reactors varied significantly.Acidovorax and Denitratisoma were the top two genera of the bacterial community in the biofilm in the PCL beads with a dominance of 26.83%and 6.67%,respectively.In the PHBV beads,Acidovorax at 17.95%and Bdellovibrio at 6.37%were the top two genera.The PCL-denitrification reactor developed in this study showed better potential than the PHBV-denitrification reactor in removing NO_(3)^(−)from aquaculture water.
基金This work was supported by Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding.
文摘The aquaculture of yellowtail kingfish(Seriola lalandi)has expanded around the globe,including China.Genetic resource of Chinese S.lalandi urgently needs to be assessed for improving production.Here,we collected wild S.lalandi samples from the Bohai Sea,China and evaluated its genetic diversity based on 17,690 nuclear loci.A population from the Southern Ocean,Australia was used for comparison.The analyses showed that the Chinese and Australian S.lalandi formed two completely distinct clusters and there was no genetic introgression from the Australian S.lalandi into the Chinese S.lalandi population.The genetic diversity is slightly lower,but comparable in Chinese versus Australian yellowtail kingfish(Chinese population,expected heterozygosity:0.19,observed heterozygosity:0.19,nucleotide diversity:0.19±0.09;Australian population,expected heterozygosity:0.23,observed heterozygosity:0.22,nucleotide diversity:0.22±0.11).Overall,our results indicated that Chinese S.lalandi could be a potential subject for genetic breeding programs.We also investigated morphological characters and developed molecular markers for population identification.Comparison of meristic characters between the Chinese population and the Australian population revealed that main shape difference were in the number of dorsal spines,dorsal fin rays and the number of upper gill rakers.Geometric morphology based on eight landmarks also revealed significant difference between the two populations including the distance between the tip of snout to origin of pelvic fin and the distance between the tip of snout to origin of pectoral fin.These morphological characters can be used for easy identification of the Chinese S.lalandi.
基金funded by the Science and Technology Innovation Committee Foundation of Shenzhen,China(Nos.JCYJ20200109141403840 and ZDSYS20220527171405012)the National Natural Science Foundation of China(No.52106045)the Pearl River Talent Recruitment Program,China(No.2019CX01Z084)。
文摘Iterative coupled methods are widely used in multi-fidelity simulation of rotating components due to the simple implementation,which iteratively eliminates the errors between the computational fluid dynamics models and approximate characteristic maps.However,the convergence and accuracy of the iterative coupled method are trapped in characteristic maps.In particular,iterative steps increase sharply as the operation point moves away from the design point.To address these problems,this paper developed an auxiliary iterative coupled method that introduces the static-pressure-auxiliary characteristic maps and modification factor of mass flow into the component-level model.The developed auxiliary method realized the direct transfer of static pressure between the high-fidelity models and the component-level model.Multi-fidelity simulations of the throttle characteristics were carried out using both the auxiliary and traditional iterative coupled methods,and the simulation results were verified using the experimental data.Additionally,the consistency between the auxiliary and traditional iterative coupled methods was confirmed.Subsequently,multi-fidelity simulations of the speed and altitude characteristics were also conducted.The auxiliary and traditional iterative coupled methods were evaluated in terms of convergence speed and accuracy.The evaluation indicated that the auxiliary iterative coupled method significantly reduces iterative steps by approximately 50%at the near-choked state.In general,the auxiliary iterative coupled method is preferred as a development of the traditional iterative coupled method in the near-choked state,and the combined auxiliary-traditional iterative coupled method provides support for successful multi-fidelity simulation in far-off-design conditions.
文摘Introduction The 2021 Annual Conference of the Housing and Community Planning Committee of the Urban Planning Society of China(UPSC)was successfully held in Beijing on Jun.5,2021.Under the guidance of the UPSC,the conference was hosted by the Housing and Community Planning Committee of the UPSC,and jointly supported by the Beijing Tsinghua Tongheng Urban Planning&Design Institute and the Specialized Committee of Community Building,Science and Technology Committee,Ministry of Housing and Urban-Rural Development.
文摘Disturbed state concept(DSC) theory maintains that the observed actual response(AR) of material under loading effects is composed of and determined by two reference state responses,namely relative intact(RI) state response and fully adjusted(FA) state response. Hardening material shows macroscopic behavior characteristics of RI response and shows negligible mesoscopic structure changes. Pore water pressure dissipation in macroscopic experiment or variance of computerized tomography(CT) value in mesoscopic experiment,as chosen characteristic parameters,can be introduced to the evolution function of disturbance factor to revise response of hardening to be response of softening. RI behavior is constituted via using hardening model. The characteristic parameters are extracted from regulations which exist in macroscopic or mesoscopic experimental data of softening material. DSC approach strategy on response prediction is presented through the combination of characteristic parameters and hardening constitutive model within the procedure of softening response prediction.
基金the Shanghai Municipal Science and Technology Commission Project(19DZ2284300).
文摘In recirculating aquaculture systems,nitrification is usually accelerated by inoculating nitrifier or mature biocarriers.In this study,the performance of the establishment of nitrification in the MBBR according to three different strategies:conventional method(Control group A),inoculation with biofloc recovered from a tilapia biofloc culture system(Group B),and addition with extra nitrite(Group C)in the Moving bed biofilm reactor(MBBR)was compared.Among them,the biofloc-inoculated group considerably accelerated the nitrification process in the MBBR(38 d),which is roughly 18 d faster than the control group(A)(56 d)and 21 d faster than group C(59 d).Less ammonia(8 mg/L NH_(4)^(+)-N,10 mg/L in other groups)and external nitrite(2 mg/L NO_(2)^(-)N)in the influent caused effluent ammonia to drop more slowly(5 d slower than the control group,8 d slower than the B group),which is detrimental to the nitrification process’development.Notably,the influent’s hydraulic retention time(HRT)was reduced from 12 h to 6 h following the successful establishment of nitrification.During the adaptation to reduced HRT,the MBBR inoculated with biofloc experienced short-term changes in the water quality index of the effluent water,whereas the other groups did not.The biofilm seeded with biofloc had the highest mean gray value ratio(1.42)of live/dead cell fluorescence,which grew better and could cover the entire groove under multiple microscope observations.However,the other groups did not demonstrate a similar trend.In summary,the research found that seeding biofloc use as nitrification bioaugmentation into the MBBR of the recirculating aquaculture system(RAS)to greatly speed up the nitrification process.
基金supported by the National Natural Science Foundation of China(Nos.61174221 and 61402039)
文摘To solve the receding horizon control （RHC） problem in an online manner, a novel numerical method called the indirect Radau pseudospectral method （IRPM） is proposed in this paper. Based on calculus of variations and the first-order necessary optimality condition, the RHC problem for linear time-varying （LTV） system is transformed into the two-point boundary value problem （TPBVP）. The Radau pseudospectral approximation is employed to discretize the TPBVP into well-posed linear algebraic equations. The resulting linear algebraic equations are solved via a matrix partitioning approach afterwards to obtain the optimal feedback control law. For the nonlinear system, the linearization method or the quasi linearization method is employed to approximate the RHC problem with successive linear approximations. Subsequently, each linear problem is solved via the similar method which is used to solve the RHC problem for LTV system. Simulation results of three examples show that the IRPM is of high accuracy and of high compu- tation efficiency to solve the RHC problem and the stability of closed-loop systems is guaranteed.
基金supported by the National Natural Science Foundation of China(Grant Nos.11902346,11502289,and 62173336)。
文摘The conventional re-entry guidance method considerably limits the maneuverability of hypersonic glide vehicles under pre-given angle-of-attack profiles.To address this issue,based on a previous three-dimensional(3D)profile guidance method,we propose a lateral-profile-first 3D profile optimization design strategy to solve the trajectory generation problem under complex conditions involving multiple constraints.Unlike the traditional method,which prioritizes the design of the longitudinal drag acceleration profiles,our method first converted the re-entry flight constraints into a lateral flight corridor,generated the initial lateral profile via parameterization,and solved the 3D profile using the coupling relationship between the longitudinal and lateral motions.The design of the 3D profile requires simultaneous consideration of waypoints,no-fly zones,and altitude profiles;hence,a new 3D profile optimization design model was constructed,and a customized sequential quadratic programming algorithm was employed to solve it.The advantages of the proposed method were demonstrated based on landing footprint results obtained using the lateral profile-first strategy.Finally,simulation results based on the common aero vehicle-high-performance model verified the feasibility and effectiveness of the strategy.
基金Supported by the National Natural Science Foundation of China (No. 70671007)the Specialized Research Fund for the Doctoral Program of Higher Education of MOE, P.R.C. (No. 20040006023)
文摘This paper describes how Chinese companies can enhance their competitive advantage through implementing enterprise information systems （EIS）. The reference framework combines strategic information system alignment and dynamic capabilities perspectives. EIS implementations were analyzed in eight companies （four in China and four in Europe）. Recommendations derived from this analysis can be used by Chinese EIS practitioners to effectively enhance organizational competitiveness through EIS implementation. The results show that Chinese companies must achieve a strategic alignment between their business strat- egy and EIS strategy and then they should facilitate EIS implementation by effectively designing managerial processes and learning mechanisms.
