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System scan of the multiplicity correlation between forward and backward rapidities in relativistic heavy-ion collisions using a multi-phase transport model

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Chinese Physics C 2022年第4期46卷 105-113页

作者： Yi-An Li Dong-Fang Wang Song Zhang Yu-Gang Ma Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China University of Chinese Academy of Sciences Beijing 100049China

A systematic study on forward–backward(FB)multiplicity correlations from large systems to small ones through a multi-phase transport model(AMPT)has been performed and the phenomenon that correlation strength increases with centrality can be explained by taking the distribution of events as the superposition of a series of Gaussian *** is also found that correlations in the η−ϕ plane can imply the shape of the ***,long-range correlations originate from the fluctuations associated with the source *** correlations allow us to decouple long-range correlations from short-range correlations,and may provide a chance to investigate the α-clustering structure in initial colliding light nuclei as *** seems the tetrahedron ^(16)O+^(16)O collision gives a more uniform and symmetrical fireball,that emits the final particles more isotropically or independently in the longitudinal direction,indicating that the forward-backward multiplicity correlation could be used to identify the pattern of α-clustered ^(16)O in future experiments.

关键词： AMPT forward-backward correlations alpha-cluster relativistic heavyion collisions

Populating ^(229m)Th via two-photon electronic bridge mechanism

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Nuclear Science and Techniques 2021年第6期32卷 45-53页

作者： Neng-Qiang Cai Guo-Qiang Zhang Chang-Bo Fu Yu-Gang Ma Shanghai Tech University Shanghai 201210China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China Shanghai Advanced research Institute Chinese Academy of SciencesShanghai 201210China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China

The isomer ^(229m)Th is the most promising candidate for clocks based on the nuclear transition because it has the lowest excitation energy of only 8.10±0.17 *** experiments and theories have focused on methods of triggering the transition between the ground state and isomeric state,among which the electronic bridge(EB)is one of the most *** this paper,we propose a new electronic bridge mechanism via two-photon excitation based on quantum optics for a two-level nuclear quantum *** long-lived 7 s1/2 electronic shell state of^(229m)Th^(3+),with a lifetime of approximately 0.6 s,is chosen as the initial state and the atomic shells(7 s-10 s)could be achieved as virtual states in a two-photon *** the virtual states return to the initial state 7 s1/2,there is a chance of triggering the nucleus 229Th^(3+),to its isomeric state ^(229m)Th ^(3+),via *** lasers at moderate intensity((10^(10)-10^(14))W/m^(2)),with photon energies near the optical range,are expected to populate the isomer at a saturated rate of approximately 10^(9) s^(-1),which is much higher than that due to other *** believe that this twophoton EB scheme can help in the development of nuclear clocks and deserves verification via a series of experiments with ordinary lasers in laboratories.

关键词： Electronic bridge ^(229)mTh Nuclear clocks Two-photon excitation

A buffer overflow detection and defense method based on RiSC-V instruction set extension

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Cybersecurity 2024年第2期7卷 28-43页

作者： Chang Liu Yan-Jun Wu Jing-Zheng Wu Chen Zhao Intelligent Software research Center Institute of SoftwareChinese Academy of SciencesBejingChina University of Chinese Academy of Sciences BeijingChina State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijingChina

Buffer overflow poses a serious threat to the memory security of modern operating *** overwrites the con-tents of other memory areas by breaking through the buffer capacity limit,destroys the system execution environ-ment,and provides implementation space for various system attacks such as program control flow *** makes it a wide range of harms.A variety of security technologies have been proposed to deal with system security problems including buffer *** example,No eXecute(NX for short)is a memory management technology commonly used in Harvard *** can refuse the execution of code which residing in a specific memory,and can effectively suppress the abnormal impact of buffer overflow on control ***,in recent years,it has also been used in the field of system security,deriving a series of solutions based on NX technology,such as ExecShield,DEP,StackGuard,***,these security solutions often rely too much on the processor archi-tecture so that the protection coverage is insufficient and the accuracy is *** in the emerging system architecture field represented by RiSC-V,there is still a lack of effective solutions for buffer overflow *** the continuous rapid development of the system architecture,it is urgent to develop defense methods that are applicable to different system application environments and oriented to all executable memory spaces to meet the needs of system security ***,we propose BOP,A new system memory security design method based on RISC-V extended instructions,to build a RISC-V buffer overflow detection and defense system and deal with the buffer overflow threat in *** to this method,NX technology can be combined with program control flow analysis,and Nx bit mechanism can be used to manage the executability of memory space,so as to achieve a more granular detection and defense of buffer overflow attacks that may occur in RISC-V system

关键词： RISc-V Operating system security Buffer overflow Control flow hijacking Nx bit Xibop

Carbon isotope and environmental changes in lakes in arid Northwest China

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Science China Earth Sciences 2019年第8期62卷 1193-1206页

作者： Weiguo LIU Xiangzhong LI Zheng WANG Huangye WANG Hu LIU Bo ZHANG Huan ZHANG Institute of Earth Environment CASState Key Laboratory of Loess and Quaternary GeologyXi’an 710061China University of Chinese Academy of Sciences Beijing 100049China

The stable carbon isotope composition(δ13 C) of lacustrine sediments, which can record changes in past environmental conditions such as the C4/C3 terrestrial vegetation composition, has been widely used for the reconstruction of terrestrial ecosystems and global climate changes. It has also been widely used in paleolimnological studies in arid northwestern China. In recent years, however, an increasing number of studies have enriched the environmental significance reflected by the stable carbon isotope geochemistry of lakes;therefore, the interpretation of lake δ13 C variations in paleoenvironmental reconstructions should be carefully evaluated from various aspects. In this paper, previous studies from the past several decades on the lacustrineδ13 C variations in arid northwestern China were reviewed, and the possible mechanisms of the δ13 C variations were *** study will provide a reference for the application of carbon isotope geochemistry in paleoenvironmental reconstructions.

关键词： Carbon isotope Lake Arid region of northwestern China Total organic carbon Organic biomarkers

Catalytic oxidation of low concentration formaldehyde over Pt/TiO_(2) catalyst

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Chinese Journal of Chemical Engineering 2021年第1期34卷 190-195页

作者： Yuan Su Keming Ji Jiayao Xun Kan Zhang Ping Liu Liang Zhao State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China

Formaldehyde(HCHO) is an important indoor *** oxidize low concentration HCHO is an effective way to eliminate indoor *** this study,a series of Pt/TiO_(2) catalysts are prepared by impregnation and reduced by NaBH_*** effects of loading amount of Pt and cry stal type of TiO_(2) on the physical and chemical properties and the catalytic performance in HCHO oxidation reaction are *** results show that the quantity of active site and the oxygen vacancy of catalysts increa sed with increasing Pt content,which is beneficial to promote the further performance of ***,with the further rises of Pt content,the specific surface area further decreases,and the proportion of Pt^(2+) species on the catalyst surface which is significant to catalytic properties also decreases,causing catalytic performance *** with the catalyst supporting on rutile,the Pt/α-TiO_(2) catalyst supporting on anatase has larger specific surface area,more Pt^(2+) phase and easier to form oxygen vacancy in the support,which cause better catalytic *** catalyst with Pt content of0.1 wt% and supported by anatase TiO_(2) has the best catalytic *** HCHO conversion efficiency reaches 98% and 100% at 50℃ and 100 ℃, and the stabilization time is longer than 140 h.

关键词： Catalyst support Catalysis Fixed-bed Pt/TiO_(2)

Synthesis and characterization of BZSM-5 and its catalytic performance in the methanol to hydrocarbons reaction

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Chinese Journal of Chemical Engineering 2021年第7期34卷 196-203页

作者： Junhua Gao Keming Ji Hao Zhou Jiayao Xun Zenghou Liu Kan Zhang Ping Liu State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China

Five kinds of BZSM-5 molecular sieve with different Si/B ratio and a SiZSM-5 molecular sieve were prepared by hydrothermal synthesis method followed by acid exchange and *** samples were characterized by XRD,SEM,FT-IR,ICP,low temperature N_(2) physical adsorption and desorption,NH3-TPD and *** catalytic performance in the reaction of methanol to hydrocarbons was evaluated in the fixed bed *** with SiZSM-5,the amount and strength of Bronsted(B)acid were enhanced by introducing skeleton boron and the activity of the catalyst was greatly *** characterization and evaluation results indicated that the BZSM-5 catalyst synthesized from the gel of SiO_(2)/B2 O320 with Si/B ratio 74.48 had modest acidity strength,acid amount of 0.18 mmol NH3·g^(-1) and large mesopore volume of 0.23 cm3·g^(-1).The B acid ratio was higher and the acid strength of BZSM-5 was weaker than that of AIZSM-5,which could inhibit the deep coke formation and increase the activity stability.B-2 had the best lifetime which could reach 672 h under the same evaluation reaction conditions,due to the best matching of moderate acidity and good diffusion properties.

关键词： ZSM-5 Catalysis Methanol Hydrocarbons

Development of a 325 MHz β=0.12 superconducting single spoke cavity for China-ADS

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Chinese Physics C 2014年第7期38卷 130-134页

作者：李菡戴建枰沙鹏王群要黄泓李黎海张娟马强林海英孙毅潘卫民 Graduate University of Chinese Academy of Sciences Institute of High Energy Physics Chinese Academy of Sciences

Twelve very low Beta superconducting single spoke cavities, whose Beta is only 0.12 （Spoke012） when operating at 325 IvIHz, are adopted in Injector I for China-ADS linac. This type of spoke cavity is believed to be one of tile key challenges for its very low geometric Beta. So far, in collaboration with Peking University and Harbin Institute of Technology, IHEP has successfully designed, fabricated, and tested the Spoke012 prototype cavity. This paper presents the details of the design, fabrication and test results for Spoke012 prototype cavity.

关键词： low beta spoke cavity EM design mechanical design fabrication cold test

Design study on very low Beta spoke cavity for China-ADS

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Chinese Physics C 2012年第8期36卷 761-764页

作者：李菡沙鹏戴建枰黄泓王群要 Graduate University of Chinese Academy of Sciences Institute of High Energy Physics Chinese Academy of Sciences

Very low Beta superconducting spoke cavity is one of the key challenges for the China-ADS project. In this paper, a new structure of 3βλ/2 spoke cavity is first studied in detail. Its RF and mechanical properties ar... 详细信息

关键词： low Beta spoke cavity 3βλ/2 spoke cavity CST-MWS

Two-dimensional Organic Metal Chalcogenides

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Chinese Journal of Structural Chemistry 2020年第12期39卷 2131-2138,2055页

作者： FU Zhi-Hua XU Gang State Key Laboratory of Stmctural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Inorganic two-dimensional(2 D)materials have attracted tremendous interests *** functionalization of 2 D materials can achieve additional functions and properties,but usually suffers from less modification ratio,poor controllability,defects and so on.2 D organic metal chalcogenide(OMC)materials with periodically arranged organic functional group between the inorganic analogues layers offer opportunities to develop adjustable electrical properties and extended *** this mini-review,we will provide an overview of the composition and preparation,band gap engineering,and conductivity modulation of the serial OMC materials and illustrate the application investigation such as biomimetic catalysis,photodetecting and chemiresistive gas sensing.

关键词： two-dimensional materials organic metal chalcogenide materials functional motif preparation band gap engineering application