Non-spherical particles exist widely in natural and industrial fluid systems and the motions of nonspherical particles are significantly different from that of spherical particles.In this paper,a simplified model of n...Non-spherical particles exist widely in natural and industrial fluid systems and the motions of nonspherical particles are significantly different from that of spherical particles.In this paper,a simplified model of non-spherical particles considering particle drag correction,lift,and rotation was established.Based on the Eulerian-Lagrangian simulation,the dispersion characteristics of spherical and nonspherical particles with different Stokes numbers in a high-speed turbulent jet were analyzed and compared considering the effect of particle rotation.The results show that,the differences in particle dispersion and radial velocity fluctuation between non-spherical particles and spherical particles in the jet are significant,especially when Stokes number is large.Moreover,the effects of different type of forces on the dispersion of non-spherical particles and spherical particles were compared in detail,which revealed that the change of the Magnus force caused by the increase in the angular velocity of non-spherical particles plays a dominant role in the differences of particle dispersion.展开更多
In this paper, we investigate the global stability of an SEIR (Susceptible-Exposed-Infected-Remove) epidemic model with infectious force under intervention strategies. To address this issue, we prove that the basic re...In this paper, we investigate the global stability of an SEIR (Susceptible-Exposed-Infected-Remove) epidemic model with infectious force under intervention strategies. To address this issue, we prove that the basic reproduction number R0 plays an essential role in determining whether the disease extincts or persists. If , there is a unique disease-free equilibrium point of the model which is globally asymptotically stable and the disease dies out, and if , there exists a unique endemic equilibrium point which is globally asymptotically stable and the disease persists.展开更多
The subgrid-scale effects on particle motion were investigated in forced isotropic turbulence by DNS and priorLES methods.In the DNS field,the importance of Kolmogorov scaling to preferential accumulation was validate...The subgrid-scale effects on particle motion were investigated in forced isotropic turbulence by DNS and priorLES methods.In the DNS field,the importance of Kolmogorov scaling to preferential accumulation was validated by comparing the radial distribution functions under various particle Stokes numbers.The prior-LES fields were generated by filtering the DNS data.The subgrid-scale Stokes number(StSGS)is a useful tool for determining the effects of subgrid-scale eddies on particle motion.The subgrid-scale eddies tend to accumulate particles with StSGSb 1 and disperse particles with 1 b StSGSb 10.For particles with StSGS?1,the effects of subgrid-scale eddies on particle motion can be neglected.In order to restore the subgrid-scale effects,the Langevin-type stochastic model with optimized parameters was adopted in this study.This model is effective for the particles with StSGS N 1 while has an adverse impact on the particles with StSGSb 1.The results show that the Langevin-type stochastic model tends to smooth the particle distribution in the isotropic turbulence.展开更多
Software an important way to vulnerability mining is detect whether there are some loopholes existing in the software, and also is an important way to ensure the secu- rity of information systems. With the rapid devel...Software an important way to vulnerability mining is detect whether there are some loopholes existing in the software, and also is an important way to ensure the secu- rity of information systems. With the rapid development of information technology and software industry, most of the software has not been rigorously tested before being put in use, so that the hidden vulnerabilities in software will be exploited by the attackers. Therefore, it is of great significance for us to actively de- tect the software vulnerabilities in the security maintenance of information systems. In this paper, we firstly studied some of the common- ly used vulnerability detection methods and detection tools, and analyzed the advantages and disadvantages of each method in different scenarios. Secondly, we designed a set of eval- uation criteria for different mining methods in the loopholes evaluation. Thirdly, we also proposed and designed an integration testing framework, on which we can test the typical static analysis methods and dynamic mining methods as well as make the comparison, so that we can obtain an intuitive comparative analysis for the experimental results. Final- ly, we reported the experimental analysis to verify the feasibility and effectiveness of the proposed evaluation method and the testingframework, with the results showing that the final test results will serve as a form of guid- ance to aid the selection of the most appropri- ate and effective method or tools in vulnera- bility detection activity.展开更多
The advantages and disadvantages of chemical leaching,phytoremediation,in-situ/ex-situ solidification and stabilization,cement kiln co-disposal and safe landfill remediation are analyzed.In addition,the application of...The advantages and disadvantages of chemical leaching,phytoremediation,in-situ/ex-situ solidification and stabilization,cement kiln co-disposal and safe landfill remediation are analyzed.In addition,the application of chemical leaching and in-situ/ex-situ solidification and stabilization technology in the treatment of heavy metal-contaminated soil in electroplating enterprises in China is introduced in detail to provide reference for the remediation of heavy metal-contaminated soil around electroplating enterprises in China.展开更多
The Lassa virus(LASV)is endemic in West Africa and causes severe hemorrhagic Lassa fever in humans.The glycoprotein complex(GPC)of LASV is highly glycosylation-modified,with 11 N-glycosylation sites.All 11 N-linked gl...The Lassa virus(LASV)is endemic in West Africa and causes severe hemorrhagic Lassa fever in humans.The glycoprotein complex(GPC)of LASV is highly glycosylation-modified,with 11 N-glycosylation sites.All 11 N-linked glycan chains play critical roles in GPC cleavage,folding,receptor binding,membrane fusion,and immune evasion.In this study,we focused on the first glycosylation site because its deletion mutant(N79Q)results in an unexpected enhanced membrane fusion,whereas it exerts little effect on GPC expression,cleavage,and receptor binding.Meanwhile,the pseudotype virus bearing GPC_(N79Q)was more sensitive to the neutralizing antibody 37.7H and was attenuated in virulence.Exploring the biological functions of the key glycosylation site on LASV GPC will help elucidate the mechanism of LASV infection and provide strategies for the development of attenuated vaccines against LASV infection.展开更多
The membrane-proximal external region(MPER)of Lassa virus(LASV)glycoprotein complex(GPC)is critical in modulating its functionality.Till now,the high-resolution structure of the intact GPC,including MPER is not availa...The membrane-proximal external region(MPER)of Lassa virus(LASV)glycoprotein complex(GPC)is critical in modulating its functionality.Till now,the high-resolution structure of the intact GPC,including MPER is not available.In this study,we used alanine substitution to scan all 16 residues located in LASV MPER.Western blotting and quantification fusion assay showed that the residues located at the C terminus of the HR2(M414 and L415)and N terminus of the MPER(K417 and Y419)are critical for GPC-mediated membrane fusion function.Furthermore,cell surface biotinylation experiments revealed that M414 A,K417 A and Y419 A expressed similar levels as WT,whereas L415 A mutant led to a reduction of mature GPC on the cell surface.Moreover,substitution of these residues with the similar residue such as M414 L,L415 I,K417 R and Y419 F would partly compensate the loss of the fusion activity caused by the alanine mutant in these sites.Results from this study showed that several key residues in the MPER region are indispensable to promote the conformational changes that drive fusion events and shed light on the structure analysis of LASV GPC and anti-LASV therapeutics.展开更多
Large eddy simulation (LES) has become a promising tool for pulverized coal combustion with the development of computational fluid dynamics (CFD) technologies in recent years. LES can better capture the unsteady featu...Large eddy simulation (LES) has become a promising tool for pulverized coal combustion with the development of computational fluid dynamics (CFD) technologies in recent years. LES can better capture the unsteady features and turbulent structures of coal jet flame than Reynolds averaged Navier Stokes (RANS). The coal-fired power plants in China are now required to be operated in a wide load range and quickly respond to the electric grid. The boiler performance of variable loads should be evaluated in terms of flow, heat transfer, and combustion processes. In this paper, LES was applied to simulate a 660 MW ultra-supercritical boiler under BMCR (boiler maximum continue rate), 75%THA-100, and 50%THA-100 conditions. The predicted gas velocities agree well with the thermal calculation and the temperature error is less than 130 K. The simulation results show that the operation load has significant effects on the boiler performance. It is also proved that LES can provide guidance for the design and operation of advanced coal-fired boilers.展开更多
基金supported by National Science and Technology Major Project of China(2019-I-0022-0021)Seed fund of Shanxi Research Institute for Clean Energy,Tsinghua Universitythe National Natural Science Foundation of China(51761125011)。
文摘Non-spherical particles exist widely in natural and industrial fluid systems and the motions of nonspherical particles are significantly different from that of spherical particles.In this paper,a simplified model of non-spherical particles considering particle drag correction,lift,and rotation was established.Based on the Eulerian-Lagrangian simulation,the dispersion characteristics of spherical and nonspherical particles with different Stokes numbers in a high-speed turbulent jet were analyzed and compared considering the effect of particle rotation.The results show that,the differences in particle dispersion and radial velocity fluctuation between non-spherical particles and spherical particles in the jet are significant,especially when Stokes number is large.Moreover,the effects of different type of forces on the dispersion of non-spherical particles and spherical particles were compared in detail,which revealed that the change of the Magnus force caused by the increase in the angular velocity of non-spherical particles plays a dominant role in the differences of particle dispersion.
文摘In this paper, we investigate the global stability of an SEIR (Susceptible-Exposed-Infected-Remove) epidemic model with infectious force under intervention strategies. To address this issue, we prove that the basic reproduction number R0 plays an essential role in determining whether the disease extincts or persists. If , there is a unique disease-free equilibrium point of the model which is globally asymptotically stable and the disease dies out, and if , there exists a unique endemic equilibrium point which is globally asymptotically stable and the disease persists.
基金Supported by the National Natural Science Foundation of China(51761125011).
文摘The subgrid-scale effects on particle motion were investigated in forced isotropic turbulence by DNS and priorLES methods.In the DNS field,the importance of Kolmogorov scaling to preferential accumulation was validated by comparing the radial distribution functions under various particle Stokes numbers.The prior-LES fields were generated by filtering the DNS data.The subgrid-scale Stokes number(StSGS)is a useful tool for determining the effects of subgrid-scale eddies on particle motion.The subgrid-scale eddies tend to accumulate particles with StSGSb 1 and disperse particles with 1 b StSGSb 10.For particles with StSGS?1,the effects of subgrid-scale eddies on particle motion can be neglected.In order to restore the subgrid-scale effects,the Langevin-type stochastic model with optimized parameters was adopted in this study.This model is effective for the particles with StSGS N 1 while has an adverse impact on the particles with StSGSb 1.The results show that the Langevin-type stochastic model tends to smooth the particle distribution in the isotropic turbulence.
基金partly supported by National Natural Science Foundation of China (NSFC grant numbers: 61202110 and 61502205)the project of Jiangsu provincial Six Talent Peaks (Grant numbers: XYDXXJS-016)
文摘Software an important way to vulnerability mining is detect whether there are some loopholes existing in the software, and also is an important way to ensure the secu- rity of information systems. With the rapid development of information technology and software industry, most of the software has not been rigorously tested before being put in use, so that the hidden vulnerabilities in software will be exploited by the attackers. Therefore, it is of great significance for us to actively de- tect the software vulnerabilities in the security maintenance of information systems. In this paper, we firstly studied some of the common- ly used vulnerability detection methods and detection tools, and analyzed the advantages and disadvantages of each method in different scenarios. Secondly, we designed a set of eval- uation criteria for different mining methods in the loopholes evaluation. Thirdly, we also proposed and designed an integration testing framework, on which we can test the typical static analysis methods and dynamic mining methods as well as make the comparison, so that we can obtain an intuitive comparative analysis for the experimental results. Final- ly, we reported the experimental analysis to verify the feasibility and effectiveness of the proposed evaluation method and the testingframework, with the results showing that the final test results will serve as a form of guid- ance to aid the selection of the most appropri- ate and effective method or tools in vulnera- bility detection activity.
文摘The advantages and disadvantages of chemical leaching,phytoremediation,in-situ/ex-situ solidification and stabilization,cement kiln co-disposal and safe landfill remediation are analyzed.In addition,the application of chemical leaching and in-situ/ex-situ solidification and stabilization technology in the treatment of heavy metal-contaminated soil in electroplating enterprises in China is introduced in detail to provide reference for the remediation of heavy metal-contaminated soil around electroplating enterprises in China.
基金the National Key Research and Development Program(2022YFC2303300,2018YFA0507204)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0490000)the Na-tional Natural Science Foundation of China(82172273,31670165).
文摘The Lassa virus(LASV)is endemic in West Africa and causes severe hemorrhagic Lassa fever in humans.The glycoprotein complex(GPC)of LASV is highly glycosylation-modified,with 11 N-glycosylation sites.All 11 N-linked glycan chains play critical roles in GPC cleavage,folding,receptor binding,membrane fusion,and immune evasion.In this study,we focused on the first glycosylation site because its deletion mutant(N79Q)results in an unexpected enhanced membrane fusion,whereas it exerts little effect on GPC expression,cleavage,and receptor binding.Meanwhile,the pseudotype virus bearing GPC_(N79Q)was more sensitive to the neutralizing antibody 37.7H and was attenuated in virulence.Exploring the biological functions of the key glycosylation site on LASV GPC will help elucidate the mechanism of LASV infection and provide strategies for the development of attenuated vaccines against LASV infection.
基金the National Key Research and Development Program of China (2018YFA0507204)the National Natural Sciences Foundation of China (31670165)+1 种基金Wuhan National Biosafety Laboratory,Chinese Academy of Sciences Advanced Customer Cultivation Project (2019ACCP-MS03)the Open Research Fund Program of the State Key Laboratory of Virology of China (2018IOV001)。
文摘The membrane-proximal external region(MPER)of Lassa virus(LASV)glycoprotein complex(GPC)is critical in modulating its functionality.Till now,the high-resolution structure of the intact GPC,including MPER is not available.In this study,we used alanine substitution to scan all 16 residues located in LASV MPER.Western blotting and quantification fusion assay showed that the residues located at the C terminus of the HR2(M414 and L415)and N terminus of the MPER(K417 and Y419)are critical for GPC-mediated membrane fusion function.Furthermore,cell surface biotinylation experiments revealed that M414 A,K417 A and Y419 A expressed similar levels as WT,whereas L415 A mutant led to a reduction of mature GPC on the cell surface.Moreover,substitution of these residues with the similar residue such as M414 L,L415 I,K417 R and Y419 F would partly compensate the loss of the fusion activity caused by the alanine mutant in these sites.Results from this study showed that several key residues in the MPER region are indispensable to promote the conformational changes that drive fusion events and shed light on the structure analysis of LASV GPC and anti-LASV therapeutics.
基金This work was funded by the National Key Research and Development Program of China(No.2017YFB0602102)the National Natural Science Foundation of China(Grant No.51761125011).
文摘Large eddy simulation (LES) has become a promising tool for pulverized coal combustion with the development of computational fluid dynamics (CFD) technologies in recent years. LES can better capture the unsteady features and turbulent structures of coal jet flame than Reynolds averaged Navier Stokes (RANS). The coal-fired power plants in China are now required to be operated in a wide load range and quickly respond to the electric grid. The boiler performance of variable loads should be evaluated in terms of flow, heat transfer, and combustion processes. In this paper, LES was applied to simulate a 660 MW ultra-supercritical boiler under BMCR (boiler maximum continue rate), 75%THA-100, and 50%THA-100 conditions. The predicted gas velocities agree well with the thermal calculation and the temperature error is less than 130 K. The simulation results show that the operation load has significant effects on the boiler performance. It is also proved that LES can provide guidance for the design and operation of advanced coal-fired boilers.
