Accelerator mass spectrometry at Peking University: experiments and progress

Chen, Chia-erh; Guo, Zhiyu; Yan, Shengqing; Li, Renxin; Xiao, Min; Li, Kun; Liu, Hongtao; Liu, Kexin; Wang, Jianjun; Li, Bin; Lu, Xiangyang; Yuan, Shijun; Tiemei, Chen; Gao, Shijun; Zheng, Shuhui; Chen, Chengye; Liu, Yan

doi:10.1016/0168-583x(94)95973-0

Cited by 20 publications

(5 citation statements)

References 4 publications

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“…It would be interesting to study higher dimensional Galilean CFT. In this case, one has to take the angular momentum quantum number into JHEP06(2021)112 account [79]. Another interesting direction is to investigate Galilean conformal bootstrap numerically.…”

Section: Jhep06(2021)112mentioning

confidence: 99%

On Galilean conformal bootstrap

Chen

Hao

Liu

et al. 2021

J. High Energ. Phys.

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In this work, we develop conformal bootstrap for Galilean conformal field theory (GCFT). In a GCFT, the Hilbert space could be decomposed into quasiprimary states and its global descendants. Different from the usual conformal field theory, the quasiprimary states in a GCFT constitute multiplets, which are block-diagonized under the Galilean boost operator. More importantly the multiplets include the states of negative norms, indicating the theory is not unitary. We compute global blocks of the multiplets, and discuss the expansion of four-point functions in terms of the global blocks of the multiplets. Furthermore we do the harmonic analysis for the Galilean conformal symmetry and obtain an inversion formula. As the first step to apply the Galilean conformal bootstrap, we construct generalized Galilean free theory (GGFT) explicitly. We read the data of GGFT by using Taylor series expansion of four-point function and the inversion formula independently, and find exact agreement. We discuss some novel features in the Galilean conformal bootstrap, due to the non-semisimpleness of the Galilean conformal algebra and the non-unitarity of the GCFTs.

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Section: Jhep06(2021)112mentioning

confidence: 99%

On Galilean conformal bootstrap

Chen

Hao

Liu

et al. 2021

J. High Energ. Phys.

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“…Twelve samples from the Bailiandong and Miaoyan sites were dated at the Peking University AMS Facility (PKUAMS) (Chen et al 1994;Guo et al 1995). We pretreated samples of charcoal and burned bones using the standard procedure, i.e., acid/alkali/acid (AAA) washing.…”

Section: Methodsmentioning

confidence: 99%

¹⁴C AMS Dating the Transition from the Paleolithic to the Neolithic in South China

et al. 1995

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To study the transition from the Paleolithic to the Neolithic period and its duration, samples of charcoal, bone, flowstone and shells excavated from Bailiandong and Miaoyan caves, Guangxi Zhuang autonomous region, South China were dated using the Peking University AMS facility and liquid scintillation counter. The remains excavated from these sites show typical characteristics of the transition from the Paleolithic to the Neolithic. Radiocarbon dating results show a rapid transition from ca. 20 to 10 ka bp.

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“…The pretreatment was performed according to the chemical procedure published by Shen et al [28] . Finally, the BeO obtained was mixed with Nb powder, pressed into a copper disc and measured by the Accelerator Mass Spectrometry (AMS) equipment at the Ministry of Education Key Laboratory of Heavy Ion Physics, Peking University [29,30] . Recently, this laboratory developed a recirculation gas stripper and improved the ion source and detector.…”

Section: Datingmentioning

confidence: 99%

Paleoenvironmental implications of high-density records in Co-rich seamount crusts from the Pacific Ocean

Wang

Zhou

Wang³

et al. 2008

Sci. China Ser. D-Earth Sci.

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Co-rich seamount crusts have been shown to possess great potential for providing information on paleoceanographic and paleoclimatic changes. High resolution data are essential to decipher and correctly understand such high-density records. With the development of modern micro-probe techniques, detailed sampling of crusts can be performed and it is possible to retrieve detailed information about environmental changes recorded in the seamount crusts. We report here geochemical results of more than 40 elements (including all rare earth elements) of four Co-rich seamount crust samples, which were collected from seamounts in the central and western Pacific Ocean. These data were obtained with two micro-probe techniques: Electron Probe Micro Analyzer and Laser Ablation Inductively Coupled Plasma Mass Spectrometry. The chronological framework of the seamount crust samples was determined using the cosmogenic 10 Be and the Co-chronometer. Records of elemental composition, P, and Al/(Fe + Mn) and Y/Ho ratios across the sections of the four samples are used to identify paleoceanographic and paleoclimatic events over the past ~30 Ma. These data show that: (1) Al/(Fe + Mn) in the western Pacific seamount crust is a useful proxy for the assessment of changes of source materials related to the variability of the Asian monsoon; (2) P and Y/Ho can be used as proxies to infer biogenic episodes. Finally we discuss the methodology related to dating and micro-probe analysis used in crust study.Co-rich seamount crust, micro-probe, chronology, geochemical record, paleo-oceanic environment During the last ten years' investigation on marine geology and mineral resources in deep oceans, marine ferro-manganese oxides, especially Co-rich seamount crusts, laminated mineral deposits, have been shown to have great potential for obtaining information on long-term paleoceanographic and paleoclimatic changes and have attracted the attention of the scientists around the world. The formation of Fe-Mn crust by deposition of ions or molecules is an extremely slow process at an average growth rate of only one atomic layer per year [1] . Therefore, Co-rich seamount crusts are virtually condensed stratigraphic sections in which several millimeters can represent one million years of oceanic history [2,3] .Great progress has been made in the study of the

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Accelerator mass spectrometry at Peking University: experiments and progress

Cited by 20 publications

References 4 publications

On Galilean conformal bootstrap

On Galilean conformal bootstrap

¹⁴C AMS Dating the Transition from the Paleolithic to the Neolithic in South China

Paleoenvironmental implications of high-density records in Co-rich seamount crusts from the Pacific Ocean

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Accelerator mass spectrometry at Peking University: experiments and progress

Cited by 20 publications

References 4 publications

On Galilean conformal bootstrap

On Galilean conformal bootstrap

14C AMS Dating the Transition from the Paleolithic to the Neolithic in South China

Paleoenvironmental implications of high-density records in Co-rich seamount crusts from the Pacific Ocean

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¹⁴C AMS Dating the Transition from the Paleolithic to the Neolithic in South China