In view of the limited space of offshore platform and the large amount of polymer injection, the dissolution time method, solution viscosity method, conductivity method, undissolved filtration method and falling ball ...In view of the limited space of offshore platform and the large amount of polymer injection, the dissolution time method, solution viscosity method, conductivity method, undissolved filtration method and falling ball method are used as the rapid detection methods of polymer dissolution. The results show that the error of conductivity method is the largest, and that of dissolution time method is the second, and both methods are time-consuming. Solution viscosity method and insolubles filtration method have small error, but they are time-consuming, especially for offshore platforms, which makes detection inconvenient. The drop ball method is simple in operation and has a small error, so it is a promising method for rapid determination of polymer dissolution time.展开更多
The signal spectral leakage and fence effect are prone to take place during the power harmonic analysis by fast fourier transform(FFT) under asynchronous sampling.The inhibiting ability of classical window functions i...The signal spectral leakage and fence effect are prone to take place during the power harmonic analysis by fast fourier transform(FFT) under asynchronous sampling.The inhibiting ability of classical window functions is restricted by side-lobe behaviors. A new type window function called time domain mutual-multiplication window, is obtained by multiplication operation of several window functions. A novel approach of harmonic analysis is developed through analyzing performances of main-lobe and side-lobe of the new window. Simulation results show that the time domain mutual-multiplication window can significantly suppress frequency spectral leakage and improve the accuracy of harmonic parameter estimation.展开更多
The development of clean,sustainable and renewable energy storage systems is in urgent need with the fast-growing energy demand in the areas of electric vehicles and mobile electronics etc.Lithium-ion batteries(LIBs)h...The development of clean,sustainable and renewable energy storage systems is in urgent need with the fast-growing energy demand in the areas of electric vehicles and mobile electronics etc.Lithium-ion batteries(LIBs)have been deemed to be the most promising energy storage devices for their high power density,long cycle life and fast charge-discharge rates[1].Transition展开更多
Introduction:Toxoplasmosis is a life-threatening complication after hematopoietic stem cell transplantation(HSCT).However,for several reasons,clinicians know little about Toxoplasma infection.Case presentation:We repo...Introduction:Toxoplasmosis is a life-threatening complication after hematopoietic stem cell transplantation(HSCT).However,for several reasons,clinicians know little about Toxoplasma infection.Case presentation:We report a case of toxoplasmosis that was diagnosed by bone marrow smear and metagenomic next-generation sequencing(mNGS)after HSCT in a boy.Additionally,we summarize the characteristics of toxoplasmosis after pediatric HSCT reported in the literature published in PubMed.Conclusion:Clinicians should increase their awareness of toxoplasmosis in children after HSCT and implement pre-transplant screening and post-transplant monitoring and prevention in future according to the national conditions of our country.展开更多
Experimental studies were conducted in order to improve the understanding of the thrust generation and the pressure/flame reverse propagation of the air-breathing pulse detonation engines(APDEs)with self-designed inle...Experimental studies were conducted in order to improve the understanding of the thrust generation and the pressure/flame reverse propagation of the air-breathing pulse detonation engines(APDEs)with self-designed inlets and valves structures.The present experimental research utilized a gasoline/air APDE(with 68 mm inner-diameter,2050 mm length and maximum operating frequency not less than 40 Hz which was as a benchmark structure)at different operating frequencies,with freestream air inflow of 1.1 atm and 0℃.The theoretical equivalence ratio of gasoline/air was 1.Two kinds of inlets with centerbody or without were considered and combined with two kinds of self-designed valves(the elastic-valve and the convergent aero-valve)specially designed for comparative experiments.During the test,the inflow parameters,the pressure along the longitudinal direction inside the engine and the thrust force were measured for the APDE operating characteristic analysis,including the detonation combustion,the aerodynamic drag,the pressure/flame reverse propagation and the thrust generation.The research results indicate that:The inlet centerbody does not increase drag but plays a positive effect on airflow stability and operation matching.The elastic-valve and the convergent aero-valve,though increase the inlet aerodynamic drag,have obvious effects on suppressing the detonation wave and pressure forward propagation,resulting in effective thrust increase.Effects of the convergent aero-valve are the best when the flow choked,while the effects of elastic-valve are better and continuously stable in a wider range of frequency.The wmaximum nondimensional thrust increases with the elastic-valve is reached about 1.12 at the frequency of 8-9 Hz,and about 0.97 with the convergent aero-valve at the frequency of 7 Hz.The maximum fuel specific impulse is 2514.6 s when using the convergent aerovalve.And this study provides technical reserve for the APDE optimization design.展开更多
The matching relationship between the spatial structure of cotton cluster root systems and soil-wetting patterns under mulched drip irrigation forms the theoretical basis for the technical design of mulched drip irrig...The matching relationship between the spatial structure of cotton cluster root systems and soil-wetting patterns under mulched drip irrigation forms the theoretical basis for the technical design of mulched drip irrigation.A 2-year field experiment was conducted,in which different soil-wetting patterns were produced by setting different emitter discharge rates.The envelopes of cotton cluster root length densities were derived using the topological methodology and used to examine the effects of different soil-wetting patterns on the spatial structure of root systems and water uptake capacity within row spaces.The results showed that the root systems in rows of cotton grown under narrower and deeper soil-wetting patterns exhibited a single-peak distribution,while those under wider and shallower soil-wetting patterns exhibited a two-peak distribution.Furthermore,cotton rows grown near mulch edges experienced lower moisture stress,and wider and shallower soil-wetting patterns contributed to greater root growth rates in the vertical direction and resulted in more even potential water uptake capacities.The findings of this study revealed that wider and shallower soil-wetting patterns were more desirable for mulched drip irrigation of cotton and should be considered in the technical design of drip irrigation systems.展开更多
文摘In view of the limited space of offshore platform and the large amount of polymer injection, the dissolution time method, solution viscosity method, conductivity method, undissolved filtration method and falling ball method are used as the rapid detection methods of polymer dissolution. The results show that the error of conductivity method is the largest, and that of dissolution time method is the second, and both methods are time-consuming. Solution viscosity method and insolubles filtration method have small error, but they are time-consuming, especially for offshore platforms, which makes detection inconvenient. The drop ball method is simple in operation and has a small error, so it is a promising method for rapid determination of polymer dissolution time.
文摘The signal spectral leakage and fence effect are prone to take place during the power harmonic analysis by fast fourier transform(FFT) under asynchronous sampling.The inhibiting ability of classical window functions is restricted by side-lobe behaviors. A new type window function called time domain mutual-multiplication window, is obtained by multiplication operation of several window functions. A novel approach of harmonic analysis is developed through analyzing performances of main-lobe and side-lobe of the new window. Simulation results show that the time domain mutual-multiplication window can significantly suppress frequency spectral leakage and improve the accuracy of harmonic parameter estimation.
基金supported by the National Natural Science Foundation of China(21377044 and 21573085)the Key Project of Natural Science Foundation of Hubei Province(2015CFA037)+1 种基金the Excellent Doctoral Dissertation Cultivation Grant from Central China Normal University(CCNU)(2017YBZZ077)‘‘Hua Bo" Plan of CCNU
文摘The development of clean,sustainable and renewable energy storage systems is in urgent need with the fast-growing energy demand in the areas of electric vehicles and mobile electronics etc.Lithium-ion batteries(LIBs)have been deemed to be the most promising energy storage devices for their high power density,long cycle life and fast charge-discharge rates[1].Transition
基金The Interdisciplinary Program of Shanghai Jiao Tong University(project number YG2021QN108)。
文摘Introduction:Toxoplasmosis is a life-threatening complication after hematopoietic stem cell transplantation(HSCT).However,for several reasons,clinicians know little about Toxoplasma infection.Case presentation:We report a case of toxoplasmosis that was diagnosed by bone marrow smear and metagenomic next-generation sequencing(mNGS)after HSCT in a boy.Additionally,we summarize the characteristics of toxoplasmosis after pediatric HSCT reported in the literature published in PubMed.Conclusion:Clinicians should increase their awareness of toxoplasmosis in children after HSCT and implement pre-transplant screening and post-transplant monitoring and prevention in future according to the national conditions of our country.
基金the National Natural Science Foundation of China(91441201)the Fundamental Research Funds for the Central Universities(5003123003)for financial supports of this work.
文摘Experimental studies were conducted in order to improve the understanding of the thrust generation and the pressure/flame reverse propagation of the air-breathing pulse detonation engines(APDEs)with self-designed inlets and valves structures.The present experimental research utilized a gasoline/air APDE(with 68 mm inner-diameter,2050 mm length and maximum operating frequency not less than 40 Hz which was as a benchmark structure)at different operating frequencies,with freestream air inflow of 1.1 atm and 0℃.The theoretical equivalence ratio of gasoline/air was 1.Two kinds of inlets with centerbody or without were considered and combined with two kinds of self-designed valves(the elastic-valve and the convergent aero-valve)specially designed for comparative experiments.During the test,the inflow parameters,the pressure along the longitudinal direction inside the engine and the thrust force were measured for the APDE operating characteristic analysis,including the detonation combustion,the aerodynamic drag,the pressure/flame reverse propagation and the thrust generation.The research results indicate that:The inlet centerbody does not increase drag but plays a positive effect on airflow stability and operation matching.The elastic-valve and the convergent aero-valve,though increase the inlet aerodynamic drag,have obvious effects on suppressing the detonation wave and pressure forward propagation,resulting in effective thrust increase.Effects of the convergent aero-valve are the best when the flow choked,while the effects of elastic-valve are better and continuously stable in a wider range of frequency.The wmaximum nondimensional thrust increases with the elastic-valve is reached about 1.12 at the frequency of 8-9 Hz,and about 0.97 with the convergent aero-valve at the frequency of 7 Hz.The maximum fuel specific impulse is 2514.6 s when using the convergent aerovalve.And this study provides technical reserve for the APDE optimization design.
基金This study was supported by the National Natural Science Foundation of China(Grant No.51790533(a major project)and No.51709266)the National Key Research and Development Program of China(Grant No.2017YFC0403303)the Central Public-interest Scientific Institution Basal Research Fund(Farmland Irrigation Research Institute,CAAS)(FIRI2016-19 and FIRI2016-16).
文摘The matching relationship between the spatial structure of cotton cluster root systems and soil-wetting patterns under mulched drip irrigation forms the theoretical basis for the technical design of mulched drip irrigation.A 2-year field experiment was conducted,in which different soil-wetting patterns were produced by setting different emitter discharge rates.The envelopes of cotton cluster root length densities were derived using the topological methodology and used to examine the effects of different soil-wetting patterns on the spatial structure of root systems and water uptake capacity within row spaces.The results showed that the root systems in rows of cotton grown under narrower and deeper soil-wetting patterns exhibited a single-peak distribution,while those under wider and shallower soil-wetting patterns exhibited a two-peak distribution.Furthermore,cotton rows grown near mulch edges experienced lower moisture stress,and wider and shallower soil-wetting patterns contributed to greater root growth rates in the vertical direction and resulted in more even potential water uptake capacities.The findings of this study revealed that wider and shallower soil-wetting patterns were more desirable for mulched drip irrigation of cotton and should be considered in the technical design of drip irrigation systems.
