An approximately 800 bp cDNA ( Lhcb 2) encoding light_harvesting chlorophyll a/b_binding protein complex (type Ⅱ) was cloned from the seedling of pea ( Pisum sativum L.) with RT_PCR method. Southern blotting usi...An approximately 800 bp cDNA ( Lhcb 2) encoding light_harvesting chlorophyll a/b_binding protein complex (type Ⅱ) was cloned from the seedling of pea ( Pisum sativum L.) with RT_PCR method. Southern blotting using special probe demonstrated that there existed one copy of Lhcb 2 in pea genome. RT_PCR and Northern blotting revealed the expression of Lhcb 2 which was regulated by light in a time_dependent expression manner. The Lhcb 2 gene didn't express untill 2 h after irradiated with white light. Low temperature (4 ℃) also affected the Lhcb 2 gene by decreasing half of its expression under 25 ℃.展开更多
As the LHC beams cannot be polarized,introducing a dense polarized gas target at the LHCb experiment at CERN,to be operated concurrently with beam-beam collisions,will facilitate fixed-target interactions to explore a...As the LHC beams cannot be polarized,introducing a dense polarized gas target at the LHCb experiment at CERN,to be operated concurrently with beam-beam collisions,will facilitate fixed-target interactions to explore a new energy regime of spin physics measurements.Unfortunately,typical surface coatings used to avoid polarization losses,such as water,Teflon,or aluminum,are prohibited due to restrictions imposed by vacuum and beam policies.The former atomic beam source for the polarized target at ANKE@COSY(Forschungszentrum Jülich),an accompanying Lamb-shift polarimeter,and a storage cell chamber inside a superconducting magnet provide a perfect test stand to investigate the properties of a storage cell coated with amorphous carbon.A significant recombination rate,ranging from 93% to 100%,and preservation of polarization during recombination surpassing 74% were observed.We successfully produced H2 molecules with a nuclear polarization of P~0.59.In addition,we could produce polarized H3+ions for the first time and observed the shift of the axis of rotation within HD molecules.展开更多
本文介绍了LHCb实验中的两项重要研究,旨在以电弱相互作用玻色子为工具探索原子核中的部分子分布函数(nuclear parton distribution functions,n PDFs).第一项研究利用质子-铅核对撞数据测量了Z玻色子的产生,用Z玻色子作为探针研究量子...本文介绍了LHCb实验中的两项重要研究,旨在以电弱相互作用玻色子为工具探索原子核中的部分子分布函数(nuclear parton distribution functions,n PDFs).第一项研究利用质子-铅核对撞数据测量了Z玻色子的产生,用Z玻色子作为探针研究量子色动力学(quantum chromodynamics,QCD)和nPDFs.通过测量Z玻色子的产生截面,研究人员可以更准确地确定和理解部分子在核物质环境中的分布,从而完善现有的QCD理论并提高nPDFs的精度.第二项研究在铅核-铅核超周边对撞中研究了J/ψ和ψ(2S)介子的光致产生.这种对撞中,两个铅核通过光子和核内胶子的相互作用产生粲夸克偶素.相干光致产生涉及光子与整个原子核的胶子相互作用,能量交换较小,原子核保持完整.该研究验证了现有的微扰QCD和胶子交换模型,并提供了关于核遮蔽效应和核内胶子分布的重要信息.LHCb实验首次测量了粲夸克偶素随横动量变化的相干光致产生截面,并观测到了衍射效应,为未来高能核物理研究提供了宝贵数据.展开更多
文摘An approximately 800 bp cDNA ( Lhcb 2) encoding light_harvesting chlorophyll a/b_binding protein complex (type Ⅱ) was cloned from the seedling of pea ( Pisum sativum L.) with RT_PCR method. Southern blotting using special probe demonstrated that there existed one copy of Lhcb 2 in pea genome. RT_PCR and Northern blotting revealed the expression of Lhcb 2 which was regulated by light in a time_dependent expression manner. The Lhcb 2 gene didn't express untill 2 h after irradiated with white light. Low temperature (4 ℃) also affected the Lhcb 2 gene by decreasing half of its expression under 25 ℃.
基金funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)-533904660。
文摘As the LHC beams cannot be polarized,introducing a dense polarized gas target at the LHCb experiment at CERN,to be operated concurrently with beam-beam collisions,will facilitate fixed-target interactions to explore a new energy regime of spin physics measurements.Unfortunately,typical surface coatings used to avoid polarization losses,such as water,Teflon,or aluminum,are prohibited due to restrictions imposed by vacuum and beam policies.The former atomic beam source for the polarized target at ANKE@COSY(Forschungszentrum Jülich),an accompanying Lamb-shift polarimeter,and a storage cell chamber inside a superconducting magnet provide a perfect test stand to investigate the properties of a storage cell coated with amorphous carbon.A significant recombination rate,ranging from 93% to 100%,and preservation of polarization during recombination surpassing 74% were observed.We successfully produced H2 molecules with a nuclear polarization of P~0.59.In addition,we could produce polarized H3+ions for the first time and observed the shift of the axis of rotation within HD molecules.
文摘本文介绍了LHCb实验中的两项重要研究,旨在以电弱相互作用玻色子为工具探索原子核中的部分子分布函数(nuclear parton distribution functions,n PDFs).第一项研究利用质子-铅核对撞数据测量了Z玻色子的产生,用Z玻色子作为探针研究量子色动力学(quantum chromodynamics,QCD)和nPDFs.通过测量Z玻色子的产生截面,研究人员可以更准确地确定和理解部分子在核物质环境中的分布,从而完善现有的QCD理论并提高nPDFs的精度.第二项研究在铅核-铅核超周边对撞中研究了J/ψ和ψ(2S)介子的光致产生.这种对撞中,两个铅核通过光子和核内胶子的相互作用产生粲夸克偶素.相干光致产生涉及光子与整个原子核的胶子相互作用,能量交换较小,原子核保持完整.该研究验证了现有的微扰QCD和胶子交换模型,并提供了关于核遮蔽效应和核内胶子分布的重要信息.LHCb实验首次测量了粲夸克偶素随横动量变化的相干光致产生截面,并观测到了衍射效应,为未来高能核物理研究提供了宝贵数据.
