To simulate explosion fragments, it is necessary to predict many variables such as fragment velocity, size distribution and projection angle. For active protection systems these predictions need to be made very quickl...To simulate explosion fragments, it is necessary to predict many variables such as fragment velocity, size distribution and projection angle. For active protection systems these predictions need to be made very quickly, before the weapon hits the target. Fast predictions also need to be made in real time simulations when the impact of many different computer models need to be assessed. The research presented in this paper focuses on creating a fast and accurate estimate of one of these variables - the initial fragment velocity. The Gurney equation was the first equation to calculate initial fragment velocity. This equation, sometimes with modifications, is still used today where finite element analysis or complex mathematical approaches are considered too computationally expensive. This paper enhances and improves Breech’s two-dimensional Gurney equation using available empirical data and the principals of conservation of momentum and energy. The results are computationally quick, providing improved accuracy for estimating initial fragment velocity. This will allow the developed model to be available for real-time simulation and fast computation, with improved accuracy when compared to existing approaches.展开更多
Klenow fragment（KF） uses the activity of a separate exonuclease to excise nucleotide, which is a crucial step in DNA replication and repair. Here is a novel sensitive and convenient method introduced for real-time m...Klenow fragment（KF） uses the activity of a separate exonuclease to excise nucleotide, which is a crucial step in DNA replication and repair. Here is a novel sensitive and convenient method introduced for real-time monitoring nucleotide excision by KF with a molecular beacon as a detecting probe in a homogeneous solution. This method, which overcomes the drawbacks of traditional methods such as discontinuity, time consuming and low sensitivity, was used to assay KF activity and the detection limit reached up to 0.4 U/mL. In addition, the method was applied to investigating the effects of metal ions and chemical drugs on the reaction. The results demonstrate that it is a potential high-throughput assay for screening inhibitors and activity analysis of KF in vitro.展开更多
为探究静磁场辅助冷冻(static magnetic field assisted freezing,SMAF)对牛肉品质的影响,采用不同强度SMAF(0、2、4、6、8、10 mT,-18℃),对比分析冷冻参数对牛背最长肌品质的影响。结果表明:与对照组相比,SMAF-6、8、10处理组相变时...为探究静磁场辅助冷冻(static magnetic field assisted freezing,SMAF)对牛肉品质的影响,采用不同强度SMAF(0、2、4、6、8、10 mT,-18℃),对比分析冷冻参数对牛背最长肌品质的影响。结果表明:与对照组相比,SMAF-6、8、10处理组相变时间分别显著缩短15%、25%和6.7%(P<0.05);SMAF处理有效提高了肌肉的持水性(解冻损失率、蒸煮损失率和离心损失率),降低了样品的ΔE(P<0.05),但对样品的pH值和硫代巴比妥酸反应物值无显著影响(P>0.05);此外,剪切力与肌原纤维小片化指数的结果一致,SMAF处理维持了牛肉的剪切力;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳结果显示,SMAF处理可以减少肉品经冷冻-解冻后蛋白质含量的降低。综上,在适当的静磁场强度下辅助冷冻,可节省冻结时间,提高肌肉持水力,减少蛋白质含量的降低,从而改善牛肉品质,其中SMAF-8处理效果最佳。展开更多
The first three-fold and four-fold fragmentation measurements in hot compound nuclei pro-duced in the reactions of a 25 MeV/u <sup>40</sup>At beam with targets of <sup>209</sup>Bi,<sup>19...The first three-fold and four-fold fragmentation measurements in hot compound nuclei pro-duced in the reactions of a 25 MeV/u <sup>40</sup>At beam with targets of <sup>209</sup>Bi,<sup>197</sup>Au,<sup>159</sup>Tb,<sup>115</sup>In,<sup>103</sup>Rh,and<sup>93</sup>Nb are presented.Various distributions are measured for these fragments,including distributions of ve-locities,relative velocities,angles,relative angles,masses,fragment mass ratios,total kinetic energies（TKE）,as well as the yield ratios of three-fold fragmentation to fission P<sub>32</sub> and the time difference △t be-tween two scissions after the formation of one compound nucleus.展开更多
文摘To simulate explosion fragments, it is necessary to predict many variables such as fragment velocity, size distribution and projection angle. For active protection systems these predictions need to be made very quickly, before the weapon hits the target. Fast predictions also need to be made in real time simulations when the impact of many different computer models need to be assessed. The research presented in this paper focuses on creating a fast and accurate estimate of one of these variables - the initial fragment velocity. The Gurney equation was the first equation to calculate initial fragment velocity. This equation, sometimes with modifications, is still used today where finite element analysis or complex mathematical approaches are considered too computationally expensive. This paper enhances and improves Breech’s two-dimensional Gurney equation using available empirical data and the principals of conservation of momentum and energy. The results are computationally quick, providing improved accuracy for estimating initial fragment velocity. This will allow the developed model to be available for real-time simulation and fast computation, with improved accuracy when compared to existing approaches.
基金Supported by the Key Project of Natural Science Foundation of China(No.90606003)the Hunan Provincial Natural Science Foundation, China(No.08JJ1002)+1 种基金the National High-Tech Research and Development Program(No.2007AA022007)the Changjiang Scholars and Innovative Research Team in University, China
文摘Klenow fragment（KF） uses the activity of a separate exonuclease to excise nucleotide, which is a crucial step in DNA replication and repair. Here is a novel sensitive and convenient method introduced for real-time monitoring nucleotide excision by KF with a molecular beacon as a detecting probe in a homogeneous solution. This method, which overcomes the drawbacks of traditional methods such as discontinuity, time consuming and low sensitivity, was used to assay KF activity and the detection limit reached up to 0.4 U/mL. In addition, the method was applied to investigating the effects of metal ions and chemical drugs on the reaction. The results demonstrate that it is a potential high-throughput assay for screening inhibitors and activity analysis of KF in vitro.
文摘为探究静磁场辅助冷冻(static magnetic field assisted freezing,SMAF)对牛肉品质的影响,采用不同强度SMAF(0、2、4、6、8、10 mT,-18℃),对比分析冷冻参数对牛背最长肌品质的影响。结果表明:与对照组相比,SMAF-6、8、10处理组相变时间分别显著缩短15%、25%和6.7%(P<0.05);SMAF处理有效提高了肌肉的持水性(解冻损失率、蒸煮损失率和离心损失率),降低了样品的ΔE(P<0.05),但对样品的pH值和硫代巴比妥酸反应物值无显著影响(P>0.05);此外,剪切力与肌原纤维小片化指数的结果一致,SMAF处理维持了牛肉的剪切力;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳结果显示,SMAF处理可以减少肉品经冷冻-解冻后蛋白质含量的降低。综上,在适当的静磁场强度下辅助冷冻,可节省冻结时间,提高肌肉持水力,减少蛋白质含量的降低,从而改善牛肉品质,其中SMAF-8处理效果最佳。
基金The project partially supported by the National Natural Science Foundation of China
文摘The first three-fold and four-fold fragmentation measurements in hot compound nuclei pro-duced in the reactions of a 25 MeV/u <sup>40</sup>At beam with targets of <sup>209</sup>Bi,<sup>197</sup>Au,<sup>159</sup>Tb,<sup>115</sup>In,<sup>103</sup>Rh,and<sup>93</sup>Nb are presented.Various distributions are measured for these fragments,including distributions of ve-locities,relative velocities,angles,relative angles,masses,fragment mass ratios,total kinetic energies（TKE）,as well as the yield ratios of three-fold fragmentation to fission P<sub>32</sub> and the time difference △t be-tween two scissions after the formation of one compound nucleus.
