The Bose-Hubbard model with an effective off-site three-body tunneling,characterized by jumps towards one another,between one atom on a site and a pair atoms on the neighborhood site,is studied systematically on a one...The Bose-Hubbard model with an effective off-site three-body tunneling,characterized by jumps towards one another,between one atom on a site and a pair atoms on the neighborhood site,is studied systematically on a one-dimensional（1D） lattice,by using the density matrix renormalization group method.The off-site trimer superfluid,condensing at momentum k = 0,emerges in the softcore Bose-Hubbard model but it disappears in the hardcore Bose-Hubbard model.Our results numerically verify that the off-site trimer superfluid phase derived in the momentum space from[Phys.Rev.A81,011601（R）（2010）]is stable in the thermodynamic limit.The off-site trimer superfluid phase,the partially off-site trimer superfluid phase and the Mott insulator phase are found,as well as interesting phase transitions,such as the continuous or first-order phase transition from the trimer superfluid phase to the Mott insulator phase.Our results are helpful in realizing this novel off-site trimer superfluid phase by cold atom experiments.展开更多
针对超载带来的道路损坏和安全隐患,提出了基于传感特征融合的公路治超非现场执法动态称重方法。采用聚偏氟乙烯(polyvinylidene fluoride,PVDF)压电薄膜轴传感器作为称重传感器,配置四个PVDF传感器,根据汽车的振动频率实施传感器间隔...针对超载带来的道路损坏和安全隐患,提出了基于传感特征融合的公路治超非现场执法动态称重方法。采用聚偏氟乙烯(polyvinylidene fluoride,PVDF)压电薄膜轴传感器作为称重传感器,配置四个PVDF传感器,根据汽车的振动频率实施传感器间隔设置。通过数据采集卡将PVDF输出的模拟信号转化为数字信号,利用数据通信线实时传输至上位机。拟单目标势概率假设密度滤波器(quasi-single-target cardinalized probability hypothesis density filter,QSTCPHD)滤波算法经改进,适用于多传感器场景,有效融合多个测量值。设计Elman反馈型神经网络模型,实现公路治超非现场执法动态称重。测试结果表明,设计方法对多种车型在不同速度下的动态称重置信度均超过0.95,表现出很高的鲁棒性,提高了交通管理效率。展开更多
对OFF沸石进行离子交换,制备出NH4-OFF沸石,然后通过Li2CO3/NH4-OFF体系的固态反应制备了不同锂离子交换度的Li-OFF沸石.对吸附氮气和氧气的Li-OFF样品进行了7Li MAS NMR表征,结果表明,所有吸附氧气样品的部分7Li MAS NMR共振峰均发生...对OFF沸石进行离子交换,制备出NH4-OFF沸石,然后通过Li2CO3/NH4-OFF体系的固态反应制备了不同锂离子交换度的Li-OFF沸石.对吸附氮气和氧气的Li-OFF样品进行了7Li MAS NMR表征,结果表明,所有吸附氧气样品的部分7Li MAS NMR共振峰均发生了顺磁位移.通过对实验谱的拟合,得知Li-OFF沸石中的锂离子可分布在3类阳离子位置(A,B和C)上,对应于3个不同位移的谱峰.Li+离子并非等比例地进入3类可交换的位置,而是优先占据主孔道中的A位置,随着交换度的升高,位能较高的C和B位置上的Li离子占有率逐渐增加.在100%固态交换度样品中,Li+离子在不同离子位的占有率分别为17%(位置B),29%(位置C)和54%(位置A).其中,位置B是O2分子不可接近的,所以Li-OFF沸石中有83%的阳离子是可以接近的.展开更多
The CRISPR/Cas9 mediates efficient gene editing but has off-target effects inconducive to animal breeding. In this study, the efficacy of CRISPR/Cas9 vectors containing different lengths of g RNA in reduction of the o...The CRISPR/Cas9 mediates efficient gene editing but has off-target effects inconducive to animal breeding. In this study, the efficacy of CRISPR/Cas9 vectors containing different lengths of g RNA in reduction of the off-target phenomenon in the bovine MSTN gene knockout fibroblast cell lines was assessed, providing insight into improved methods for livestock breeding. A 20-bp g RNA was designed for the second exon of the bovine MSTN gene, and CRISPR/Cas9-B was constructed to guide the Cas9 protein to the AGAACCAGGAGAAGATGGACTGG site. The alternative CRISPR/Cas9-19, CRISPR/Cas9-18, CRISPR/Cas9-17 and CRISPR/Cas9-15 vectors were constructed using g RNAs truncated by 1, 2, 3 and 5 bp, respectively. These vectors were then introduced into bovine fetal fibroblasts by the electroporation method, and single cells were obtained by flow cytometry sorting. PCR was performed for each off-target site. All samples were sequenced and analyzed, and finally the efficiency of each vector in target and off-target sites was compared. The CRISPR/Cas9-B vector successfully knocked out the MSTN gene, but the off-target phenomenon was observed. The efficiencies of CRISPR/Cas-B, CRISPR/Cas9-19, CRISPR/Cas9-18, CRISPR/Cas9-17 and CRISPR/Cas9-15 in triggering gene mutations at MSTN targeting sites were 62.16, 17.39, 7.69, 74.29 and 3.85%, respectively;rates of each at the Off-MSTN-1 locus were 52.86, 0, 0, 8.82 and 0%, respectively;all were 0% at the Off-MSTN-2 locus;rates at the Off-MSTN-3 site were 44.87, 51.72, 86.36, 0 and 50%, respectively. The efficiency of the CRISPR/Cas9-17 plasmid in the MSTN site was higher than that in the CRISPR/Cas9-B plasmid, and the effect at the three off-target sites was significantly lower. This study demonstrated that the CRISPR/Cas9-17 plasmid constructed by truncating 3 bp g RNA can effectively reduce the off-target effect without reducing the efficiency of bovine MSTN gene targeting. This finding will provide more effective gene editing strategy for use of CRISPR/Cas9 technology.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11305113)the Project GDW201400042 for the“High End Foreign Experts Program”
文摘The Bose-Hubbard model with an effective off-site three-body tunneling,characterized by jumps towards one another,between one atom on a site and a pair atoms on the neighborhood site,is studied systematically on a one-dimensional（1D） lattice,by using the density matrix renormalization group method.The off-site trimer superfluid,condensing at momentum k = 0,emerges in the softcore Bose-Hubbard model but it disappears in the hardcore Bose-Hubbard model.Our results numerically verify that the off-site trimer superfluid phase derived in the momentum space from[Phys.Rev.A81,011601（R）（2010）]is stable in the thermodynamic limit.The off-site trimer superfluid phase,the partially off-site trimer superfluid phase and the Mott insulator phase are found,as well as interesting phase transitions,such as the continuous or first-order phase transition from the trimer superfluid phase to the Mott insulator phase.Our results are helpful in realizing this novel off-site trimer superfluid phase by cold atom experiments.
文摘针对超载带来的道路损坏和安全隐患,提出了基于传感特征融合的公路治超非现场执法动态称重方法。采用聚偏氟乙烯(polyvinylidene fluoride,PVDF)压电薄膜轴传感器作为称重传感器,配置四个PVDF传感器,根据汽车的振动频率实施传感器间隔设置。通过数据采集卡将PVDF输出的模拟信号转化为数字信号,利用数据通信线实时传输至上位机。拟单目标势概率假设密度滤波器(quasi-single-target cardinalized probability hypothesis density filter,QSTCPHD)滤波算法经改进,适用于多传感器场景,有效融合多个测量值。设计Elman反馈型神经网络模型,实现公路治超非现场执法动态称重。测试结果表明,设计方法对多种车型在不同速度下的动态称重置信度均超过0.95,表现出很高的鲁棒性,提高了交通管理效率。
文摘对OFF沸石进行离子交换,制备出NH4-OFF沸石,然后通过Li2CO3/NH4-OFF体系的固态反应制备了不同锂离子交换度的Li-OFF沸石.对吸附氮气和氧气的Li-OFF样品进行了7Li MAS NMR表征,结果表明,所有吸附氧气样品的部分7Li MAS NMR共振峰均发生了顺磁位移.通过对实验谱的拟合,得知Li-OFF沸石中的锂离子可分布在3类阳离子位置(A,B和C)上,对应于3个不同位移的谱峰.Li+离子并非等比例地进入3类可交换的位置,而是优先占据主孔道中的A位置,随着交换度的升高,位能较高的C和B位置上的Li离子占有率逐渐增加.在100%固态交换度样品中,Li+离子在不同离子位的占有率分别为17%(位置B),29%(位置C)和54%(位置A).其中,位置B是O2分子不可接近的,所以Li-OFF沸石中有83%的阳离子是可以接近的.
基金supported by the National Transgenic Project of China (2016ZX08010001-002 and 2016ZX08010005-001)the National Natural Science Foundation of China (81471001)the Inner Mongolia Science and Technology Program, China (201502073)
文摘The CRISPR/Cas9 mediates efficient gene editing but has off-target effects inconducive to animal breeding. In this study, the efficacy of CRISPR/Cas9 vectors containing different lengths of g RNA in reduction of the off-target phenomenon in the bovine MSTN gene knockout fibroblast cell lines was assessed, providing insight into improved methods for livestock breeding. A 20-bp g RNA was designed for the second exon of the bovine MSTN gene, and CRISPR/Cas9-B was constructed to guide the Cas9 protein to the AGAACCAGGAGAAGATGGACTGG site. The alternative CRISPR/Cas9-19, CRISPR/Cas9-18, CRISPR/Cas9-17 and CRISPR/Cas9-15 vectors were constructed using g RNAs truncated by 1, 2, 3 and 5 bp, respectively. These vectors were then introduced into bovine fetal fibroblasts by the electroporation method, and single cells were obtained by flow cytometry sorting. PCR was performed for each off-target site. All samples were sequenced and analyzed, and finally the efficiency of each vector in target and off-target sites was compared. The CRISPR/Cas9-B vector successfully knocked out the MSTN gene, but the off-target phenomenon was observed. The efficiencies of CRISPR/Cas-B, CRISPR/Cas9-19, CRISPR/Cas9-18, CRISPR/Cas9-17 and CRISPR/Cas9-15 in triggering gene mutations at MSTN targeting sites were 62.16, 17.39, 7.69, 74.29 and 3.85%, respectively;rates of each at the Off-MSTN-1 locus were 52.86, 0, 0, 8.82 and 0%, respectively;all were 0% at the Off-MSTN-2 locus;rates at the Off-MSTN-3 site were 44.87, 51.72, 86.36, 0 and 50%, respectively. The efficiency of the CRISPR/Cas9-17 plasmid in the MSTN site was higher than that in the CRISPR/Cas9-B plasmid, and the effect at the three off-target sites was significantly lower. This study demonstrated that the CRISPR/Cas9-17 plasmid constructed by truncating 3 bp g RNA can effectively reduce the off-target effect without reducing the efficiency of bovine MSTN gene targeting. This finding will provide more effective gene editing strategy for use of CRISPR/Cas9 technology.
