[Objective] Torque teno virus （TIT） is a novel virus with negative single-strand DNA discovered in recent years, which is ubiquitous and nonpatho- genie. Torque teno sus virus （TrsuV） is widely prevalent in swine ...[Objective] Torque teno virus （TIT） is a novel virus with negative single-strand DNA discovered in recent years, which is ubiquitous and nonpatho- genie. Torque teno sus virus （TrsuV） is widely prevalent in swine populations, which is considered to be associated with some diseases such as post-weaning multi- systemic wasting syndrome （PMWS）. This study aimed to provided data for epidemiology of Tl＇suV in Guangdong Province. [Method] PCR primers were synthe- sized based on untranslated region （UTR） segment of TYsuV genome, to conduct PCR detection of 14 swine serum samples from two swine farms in Guangdong Province. A total of four PCR products of TrsuV1 and TrsuV2 from two swine farms were selected for cloning, sequencing and analysis. [ Result] Ten TrsuVl pos- itive samples （71% ） and eight TrsuV2 positive samples （57%） were obtained by PCR, including five double-positive samples （36%）. Sequence analysis of PCR products and reference strains showed that the UTR segments of samples GDTI-1 and GDT1-2 were both 305 bp, sharing 90.2% -95.1% similarity with Tl＇suVl reference strain, and the UTR segments of samples GDT2-1 and GDT2-2 were respectively 259 bp and 248 bp, sharing 67.3% - 100% similarity with TrsuV2 refer- ence strain. [ Conclusion] These results conformed that there are at least two types of Tl＇suV in Guangdong Province, with relatively high detection rates in some swine farms. Despite the putative harmlessness of Tl＇suV, the public health significance of TTsuV is noticeable due to its potential pathogenicity.展开更多
To benefit from recent advances in modeling and computational algorithms,as well as the availability of new covariance data,sensitivity and uncertainty analyses are needed to quantify the impact of uncertain sources o...To benefit from recent advances in modeling and computational algorithms,as well as the availability of new covariance data,sensitivity and uncertainty analyses are needed to quantify the impact of uncertain sources on the design parameters of small prismatic high-temperature gascooled reactors(HTGRs).In particular,the contribution of nuclear data to the k_(eff)uncertainty is an important part of the uncertainty analysis of small-sized HTGR physical calculations.In this study,a small-sized HTGR designed by China Nuclear Power Engineering Co.,Ltd.was selected for k_(eff)uncertainty analysis during full lifetime burnup calculations.Models of the cold zero power(CZP)condition and full lifetime burnup process were constructed using the Reactor Monte Carlo Code RMC for neutron transport calculation,depletion calculation,and sensitivity and uncertainty analysis.For the sensitivity analysis,the Contribution-Linked eigenvalue sensitivity/Uncertainty estimation via Track length importance Characterization(CLUTCH)method was applied to obtain sensitive information,and the "sandwich" method was used to quantify the k_(eff)uncertainty.We also compared the k_(eff)uncertainties to other typical reactors.Our results show that ^(235)U is the largest contributor to k_(eff)uncertainty for both the CZP and depletion conditions,while the contribution of ^(239)Pu is not very significant because of the design of low discharge burnup.It is worth noting that the radioactive capture reaction of ^(28)Si significantly contributes to the k_(eff)uncertainty owing to its specific fuel design.However,the k_(eff)uncertainty during the full lifetime depletion process was relatively stable,only increasing by 1.12%owing to the low discharge burnup design of small-sized HTGRs.These numerical results are beneficial for neutronics design and core parameters optimization in further uncertainty propagation and quantification study for small-sized HTGR.展开更多
Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ...Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle, received wide acceptance in finite element analysis, and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades, with particular emphasis on nonlinear finite element analysis of reinforced concrete structures.展开更多
In addition to being used for pattern transfer,the negative photoresist SU-8 iswidely used as a structural material in microelectromechanical systems(MEMS).Due to its good photopatternability,SU-8 has lower manufactur...In addition to being used for pattern transfer,the negative photoresist SU-8 iswidely used as a structural material in microelectromechanical systems(MEMS).Due to its good photopatternability,SU-8 has lower manufacturing costs than many other materials,but its mechanical properties are relatively weak to some extent,which limits its performance.The mechanical properties of epoxy-like SU-8 can be enhanced by addingmicro-or nano-fillers such as carbon nanotube,clay,and SiC nanowire,which have superior elastic modulus.In this study,SiC nanowires were used to improve the mechanical properties of SU-8 while the SU-8 retains its photopatternability.The SiC nanowires were uniformly dispersed in SU-8 by stirring and ultrasonication.SU-8 materials with different SiC nanowire contents were fabricated into dog bone samples by lithography.The elastic modulus,storage modulus,and damping factor of the samples were measured by the Dynamic mechanical analysis(DMA)Q800.The experiment result shows that the rigidity and toughness increased,and the damping reduced.The 2 wt%SiC nanowires-reinforced SU-8 had a 73.88%increase in elastic modulus and a 103.4%increase in elongation at break.Furthermore,a spring component made by SiC-doped SU-8 could withstand greater acceleration.The SiC nanowires-reinforced SU-8 has the potential tomeet higher requirements in the design andmanufacture of MEMS and greatly reduce the manufacturing costs of MEMS devices.展开更多
基金Supported by Funding Project of Guangdong Science and Technology Department(No.2011B010500023)Funding Project of Guangzhou Science and Information Technology Department(No.12A64071507)
文摘[Objective] Torque teno virus （TIT） is a novel virus with negative single-strand DNA discovered in recent years, which is ubiquitous and nonpatho- genie. Torque teno sus virus （TrsuV） is widely prevalent in swine populations, which is considered to be associated with some diseases such as post-weaning multi- systemic wasting syndrome （PMWS）. This study aimed to provided data for epidemiology of Tl＇suV in Guangdong Province. [Method] PCR primers were synthe- sized based on untranslated region （UTR） segment of TYsuV genome, to conduct PCR detection of 14 swine serum samples from two swine farms in Guangdong Province. A total of four PCR products of TrsuV1 and TrsuV2 from two swine farms were selected for cloning, sequencing and analysis. [ Result] Ten TrsuVl pos- itive samples （71% ） and eight TrsuV2 positive samples （57%） were obtained by PCR, including five double-positive samples （36%）. Sequence analysis of PCR products and reference strains showed that the UTR segments of samples GDTI-1 and GDT1-2 were both 305 bp, sharing 90.2% -95.1% similarity with Tl＇suVl reference strain, and the UTR segments of samples GDT2-1 and GDT2-2 were respectively 259 bp and 248 bp, sharing 67.3% - 100% similarity with TrsuV2 refer- ence strain. [ Conclusion] These results conformed that there are at least two types of Tl＇suV in Guangdong Province, with relatively high detection rates in some swine farms. Despite the putative harmlessness of Tl＇suV, the public health significance of TTsuV is noticeable due to its potential pathogenicity.
基金supported by the National Natural Science Foundation of China(No.12075067)the National Key R&D Program of China(No.2018YFE0180900)。
文摘To benefit from recent advances in modeling and computational algorithms,as well as the availability of new covariance data,sensitivity and uncertainty analyses are needed to quantify the impact of uncertain sources on the design parameters of small prismatic high-temperature gascooled reactors(HTGRs).In particular,the contribution of nuclear data to the k_(eff)uncertainty is an important part of the uncertainty analysis of small-sized HTGR physical calculations.In this study,a small-sized HTGR designed by China Nuclear Power Engineering Co.,Ltd.was selected for k_(eff)uncertainty analysis during full lifetime burnup calculations.Models of the cold zero power(CZP)condition and full lifetime burnup process were constructed using the Reactor Monte Carlo Code RMC for neutron transport calculation,depletion calculation,and sensitivity and uncertainty analysis.For the sensitivity analysis,the Contribution-Linked eigenvalue sensitivity/Uncertainty estimation via Track length importance Characterization(CLUTCH)method was applied to obtain sensitive information,and the "sandwich" method was used to quantify the k_(eff)uncertainty.We also compared the k_(eff)uncertainties to other typical reactors.Our results show that ^(235)U is the largest contributor to k_(eff)uncertainty for both the CZP and depletion conditions,while the contribution of ^(239)Pu is not very significant because of the design of low discharge burnup.It is worth noting that the radioactive capture reaction of ^(28)Si significantly contributes to the k_(eff)uncertainty owing to its specific fuel design.However,the k_(eff)uncertainty during the full lifetime depletion process was relatively stable,only increasing by 1.12%owing to the low discharge burnup design of small-sized HTGRs.These numerical results are beneficial for neutronics design and core parameters optimization in further uncertainty propagation and quantification study for small-sized HTGR.
文摘Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle, received wide acceptance in finite element analysis, and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades, with particular emphasis on nonlinear finite element analysis of reinforced concrete structures.
基金supports from the Shanghai Professional Technical Service Platform for Non-Silicon Micro-Nano Integrated ManufacturingProject funded by China Postdoctoral Science Foundation (No. 2018M630440)
文摘In addition to being used for pattern transfer,the negative photoresist SU-8 iswidely used as a structural material in microelectromechanical systems(MEMS).Due to its good photopatternability,SU-8 has lower manufacturing costs than many other materials,but its mechanical properties are relatively weak to some extent,which limits its performance.The mechanical properties of epoxy-like SU-8 can be enhanced by addingmicro-or nano-fillers such as carbon nanotube,clay,and SiC nanowire,which have superior elastic modulus.In this study,SiC nanowires were used to improve the mechanical properties of SU-8 while the SU-8 retains its photopatternability.The SiC nanowires were uniformly dispersed in SU-8 by stirring and ultrasonication.SU-8 materials with different SiC nanowire contents were fabricated into dog bone samples by lithography.The elastic modulus,storage modulus,and damping factor of the samples were measured by the Dynamic mechanical analysis(DMA)Q800.The experiment result shows that the rigidity and toughness increased,and the damping reduced.The 2 wt%SiC nanowires-reinforced SU-8 had a 73.88%increase in elastic modulus and a 103.4%increase in elongation at break.Furthermore,a spring component made by SiC-doped SU-8 could withstand greater acceleration.The SiC nanowires-reinforced SU-8 has the potential tomeet higher requirements in the design andmanufacture of MEMS and greatly reduce the manufacturing costs of MEMS devices.
