Two new C-glucoside flavonoids, namely 8-C-b-D-(2-O-acetyl) glucofuranosyl apigenin and 3-O-acetylvitexin, were isolated from leaves of Crataegus pinnatifida Bge. var. major N. E. Br.. Their structures were elucidated...Two new C-glucoside flavonoids, namely 8-C-b-D-(2-O-acetyl) glucofuranosyl apigenin and 3-O-acetylvitexin, were isolated from leaves of Crataegus pinnatifida Bge. var. major N. E. Br.. Their structures were elucidated by the spectroscopic means and chemical evidence.展开更多
The heavy constituent quark pair of the heavy quarkonium is produced perturbatively and subsequently undergoes hadronization into the bound state non-perturbatively.The production of the heavy quarkonium is essential ...The heavy constituent quark pair of the heavy quarkonium is produced perturbatively and subsequently undergoes hadronization into the bound state non-perturbatively.The production of the heavy quarkonium is essential to testing our understanding of quantum chromodynamics(QCD)in both perturbative and non-perturbative aspects.The electron-positron collider will provide a suitable platform for the precise study of the heavy quarkonium.The higher excited heavy quarkonium may contribute significantly to the ground states,which should be considered for sound estimation.We study the production rates of the higher excited states quarkonium pair in■at the future Z factory under the non-relativistic QCD(NRQCD)framework,where the■represents the color-singlet states■The differential angle distribution of cross sections■is given.We also discuss the uncertainties of cross sections caused by the varying quark masses and the renormalization scaleμ.We show that significant numbers of events for pairs of higher excited state quarkonia can be generated at the super Z factory.展开更多
针对BOTDR分布式光纤传感技术中背向散射光中布里渊散射信号光的分离提取问题,设计了一种高消光比双通道可调M-Z干涉仪,该干涉仪由两个3 d B耦合器、电动光纤延迟线、偏振控制器及光隔离器构成。使用C波段宽带光源(ASE)对M-Z干涉仪性能...针对BOTDR分布式光纤传感技术中背向散射光中布里渊散射信号光的分离提取问题,设计了一种高消光比双通道可调M-Z干涉仪,该干涉仪由两个3 d B耦合器、电动光纤延迟线、偏振控制器及光隔离器构成。使用C波段宽带光源(ASE)对M-Z干涉仪性能进行了检测。并将脉宽为100 ns,重复频率为20 k Hz的脉冲光入射到长度为5 km的普通单模光纤中,将其产生的背向散射光经过M-Z干涉仪滤波后,通过光谱仪检测其输出的光谱信号。实验结果表明该干涉仪能够实现大范围高精度可调节滤波功能,对瑞利散射光的抑制超过20d B,可以有效地将背向散射光中的布里渊散射光信号分离提取出来。展开更多
文摘Two new C-glucoside flavonoids, namely 8-C-b-D-(2-O-acetyl) glucofuranosyl apigenin and 3-O-acetylvitexin, were isolated from leaves of Crataegus pinnatifida Bge. var. major N. E. Br.. Their structures were elucidated by the spectroscopic means and chemical evidence.
基金Supported by the Scientific Research Fund of Chengdu University of Information Technology(KYTZ2022113)the National Key Research and Development Plan of China,Key Project of Cyberspace Security Governance(2022YFB3103103)。
文摘The heavy constituent quark pair of the heavy quarkonium is produced perturbatively and subsequently undergoes hadronization into the bound state non-perturbatively.The production of the heavy quarkonium is essential to testing our understanding of quantum chromodynamics(QCD)in both perturbative and non-perturbative aspects.The electron-positron collider will provide a suitable platform for the precise study of the heavy quarkonium.The higher excited heavy quarkonium may contribute significantly to the ground states,which should be considered for sound estimation.We study the production rates of the higher excited states quarkonium pair in■at the future Z factory under the non-relativistic QCD(NRQCD)framework,where the■represents the color-singlet states■The differential angle distribution of cross sections■is given.We also discuss the uncertainties of cross sections caused by the varying quark masses and the renormalization scaleμ.We show that significant numbers of events for pairs of higher excited state quarkonia can be generated at the super Z factory.
文摘针对BOTDR分布式光纤传感技术中背向散射光中布里渊散射信号光的分离提取问题,设计了一种高消光比双通道可调M-Z干涉仪,该干涉仪由两个3 d B耦合器、电动光纤延迟线、偏振控制器及光隔离器构成。使用C波段宽带光源(ASE)对M-Z干涉仪性能进行了检测。并将脉宽为100 ns,重复频率为20 k Hz的脉冲光入射到长度为5 km的普通单模光纤中,将其产生的背向散射光经过M-Z干涉仪滤波后,通过光谱仪检测其输出的光谱信号。实验结果表明该干涉仪能够实现大范围高精度可调节滤波功能,对瑞利散射光的抑制超过20d B,可以有效地将背向散射光中的布里渊散射光信号分离提取出来。
