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Science Bulletin 2019年第11期64卷 774-781页

作者： Ling Peng Jing-Wen Yao Mei Wang Lin-Ye Wang Xiao-Lan Huang Xin-Feng Wei Dong-Ge Ma Yong Cao Xu-Hui Zhu State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices South China University of Technology (SCUT)

It has been challenging to develop deep blue organic molecular fluorescent emitters with CIE y(y≤0.08)based on triplet-triplet annihilation(TTA). Here, we report facilely available dianthracenylphenylenebased emitters, which have a 3,5-di(4-t-butylphenyl)phenyl moiety at the one end and 4-cyanophenyl or 3-pyridyl at the other end, respectively. Both fluorophores show a high glass transition temperature of over 220℃ with a thermal decomposition temperature of over 430℃ at an initial weight loss of1%. The preliminary characterizations of the organic light-emitting diodes(OLEDs) that utilized these nondoped emitters provided high EQEs of 4.6%à5.9% with CIE coordinates(0.15, 0.07–0.08). The analysis of the EL transient decay revealed that TTA contributed to the observed performance. The results show that the new emitters are attractive as a potential TTA-based host to afford stable deep blue fluorescent OLEDs.

关键词： Anthracene Deep blue emission Fluorescence Organic light-emitting diodes Triplet-triplet annihilation

Radiative suppression of exciton-exciton annihilation in a two-dimensional semiconductor

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Light(Science & Applications) 2023年第9期12卷 1911-1920页

作者： Luca Sortino Merve Gülmüs Benjamin Tilmann Leonardo de S.Menezes Stefan A.Maier Chair in Hybrid Nanosystems Nanoinstitute MunichFaculty of PhysicsLudwig-Maximilians-Universität München80539 MunichGermany Center for NanoScience Faculty of PhysicsLudwig-Maximilians-Universität München80539 MunichGermany Departamento de Física Universidade Federal de Pernambuco50670-901 Recife-PEBrazil School of Physics and Astronomy Monash UniversityClaytonVIC 3800Australia The Blackett Laboratory Department of PhysicsImperial College LondonLondon SW72BWUK

Two-dimensional(2D)semiconductors possess strongly bound excitons,opening novel opportunities for engineering light-matter interaction at the nanoscale.However,their in-plane confinement leads to large non-radiative exciton–exciton annihilation(EEA)processes,setting a fundamental limit for their photonic applications.In this work,we demonstrate suppression of EEA via enhancement of light-matter interaction in hybrid 2D semiconductor-dielectric nanophotonic platforms,by coupling excitons in WS2 monolayers with optical Mie resonances in dielectric nanoantennas.The hybrid system reaches an intermediate light-matter coupling regime,with photoluminescence enhancement factors up to 102.Probing the exciton ultrafast dynamics reveal suppressed EEA for coupled excitons,even under high exciton densities>10^(12)cm^(−2).We extract EEA coefficients in the order of 10^(−3),compared to 10^(−2)for uncoupled monolayers,as well as a Purcell factor of 4.5.Our results highlight engineering the photonic environment as a route to achieve higher quantum efficiencies,for low-power hybrid devices,and larger exciton densities,towards strongly correlated excitonic phases in 2D semiconductors.

关键词： annihilation dielectric coupling

Direct Detection of Dark Matter with Resonant annihilation

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Communications in Theoretical Physics 2015年第7期64卷 119-126页

作者：李博周宇峰 State Key Laboratory of Theoretical Physics Kavli Institute for Theoretical Physics China Institute of Theoretical Physics Chinese Academy of Sciences

In the scenario where the dark matter(DM) particles χχˉ pair annihilate through a resonance particle R,the constraint from DM relic density makes the corresponding cross section for DM-nuclei elastic scattering extremely small, and can be below the neutrino background induced by the coherent neutrino-nuclei scattering, which makes the DM particle beyond the reach of the conventional DM direct detection experiments. We present an improved analytical calculation of the DM relic density in the case of resonant DM annihilation for s- and p-wave cases and invesitgate the condition for the DM-nuclei scattering cross section to be above the neutrino background. We show that in Higgs-portal type models, for DM particles with s-wave annihilation, the spin-independent DM-nucleus scattering cross section is proportional to ΓR/mR, the ratio of the decay width and the mass of R. For a typical DM particle mass ～ 50 Ge V,the condition leads to ΓR/mR≥O(10-4). In p-wave annihilation case, the spin-independent scattering cross section is insensitive to ΓR/mR, and is always above the neutrino background, as long as the DM particle is lighter than the top quark. The real singlet DM model is discussed as a concrete example.

关键词： resonant annihilation relic density neutrino backg

Mapping of the lunar surface by average atomic number based on positron annihilation radiation from Chang'e-1

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Earth and Planetary Physics 2018年第3期2卷 238-246页

作者： LiangQuan Ge JianKun Zhao QingXian Zhang YaoYao Luo Yi Gu College of Applied Nuclear Technology and Automation Engineering Chengdu University of Technology School of Nuclear Science and Engineering East China University of Technology

A map of the average atomic number of lunar rock and soil can be used to differentiate lithology and soil type on the lunar surface.This paper establishes a linear relationship between the average atomic number of lunar rock or soil and the flux of position annihilation radiation(0.512-Me V gamma-ray) from the lunar surface.The relationship is confirmed by Monte Carlo simulation with data from lunar rock or soil samples collected by Luna(Russia) and Apollo(USA) missions.A map of the average atomic number of the lunar rock and soil on the lunar surface has been derived from the Gamma-Ray Spectrometer data collected by Chang'e-1,an unmanned Chinese lunar-orbiting spacecraft.In the map,the higher average atomic numbers(ZA > 12.5),which are related to different types of basalt,are in the maria region;the highest ZA(13.2) readings are associated with Sinus Aestuum.The middle ZA(~12.1) regions,in the shape of irregular oval rings,are in West Oceanus Procellarum and Mare Frigoris,which seems to be consistent with the distribution of potassium,rare earth elements,and phosphorus as a unique feature on the lunar surface.The lower average atomic numbers(ZA < 11.5)are found to be correlated with the anorthosite on the far side of the Moon.

关键词： average atomic number Lunar rock and soil positron annihilation radiation Monte Carlo simulation Chang’e-1 Gamma-ray spectrometer

Interaction behaviours of solitoffs:fission, fusion, reconnection and annihilation

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Chinese Physics B 2010年第10期19卷 25-33页

作者：李军民梁祖峰唐晓艳 Department of Physics Shanghai Jiao Tong University Department of Physics Hangzhou Normal University

The interactions between solitoffs are extensively investigated. Besides the known solitoff fission and fusion interac- tions, two new types of solitoff interactions are discovered, named the solitoff reconnection and the solitoff annihilation. Taking the asymmetric Nizhnik-Novikov Veselov equation as an illustrative system, five types of solitoff interactions are graphically revealed on the basis of the analytical solution obtained by the modified tanh function expansion method.

关键词： fission fusion reconnection annihilation

Pure annihilation type D→PP(V) decays in the perturbative QCD approach

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Chinese Physics C 2013年第9期37卷 1-5页

作者：邹芝田李承吕才典 Institute of High Energy Physics and Theoretical Physics Center for Science Facilities Chinese Academy of Sciences

The annihilation type diagrams are difficult to calculate in any kind of model or method. Encouraged by the successful calculation of pure annihilation type B decays in the perturbative QCD factorization approach, we calculate the pure annihilation type D→ PP（V） decays in the perturbative QCD approach based on the kw factorization. Although the expansion parameter 1lind is not very small, our leading order numerical results agree with the existing experimental data for most channels. We expect more accurate observation from experiments, which can help us learn about the dynamics of D meson weak decays.

关键词： D meson perturbative QCD annihilation

Effects of thermal aging on Fe ion-irradiated Fe–0.6%Cu alloy investigated by positron annihilation

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Nuclear Science and Techniques 2017年第2期28卷 8-11页

作者： Yuan-Chao Hu Xing-Zhong Cao Peng Zhang Hidetsugu Tsuchida Qiu Xu Shuo-Xue Jin Er-Yang Lu Yu-Xiao Li Run-Sheng Yu Bao-Yi Wang Long Wei Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China College of Physical Engineering Zhengzhou UniversityZhengzhou 450001 China Quantum Science and Engineering Center Kyoto UniversityUji 6110011 Japan Research Reactor Institute Kyoto UniversityOsaka 5900494 Japan

Thermal aging effects on surface of 2.5 Me V Fe ion-irradiated Fe–0.6%Cu alloy were investigated using positron annihilation techniques. The samples were irradiated at 573 K to a dose of 0.1 dpa. Their thermal aging was performed at 573 K for 5, 50 and 100 h. From the results of Doppler broadening measurement, an obvious trough could be seen in near-surface region from the S parameters and inflection point form at S–W curves. This indicates changes in the annihilation mechanism of positrons in surface region after thermal aging. Coincident Doppler broadening indicates that the density of Cu precipitates in the thermal aged samples decreased, due to recovery of the vacancies.

关键词： Fe–Cu alloy Positron annihilation Irradiation Thermal aging

Towards Determining Kinetics of annihilation Electrogenerated Chemiluminescence by Concentration-Dependent Luminescent Intensity

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Journal of Analysis and Testing 2019年第2期3卷 160-165页

作者： Klaus Mathwig Neso Sojic Groningen Research Institute of Pharmacy Pharmaceutical AnalysisUniversity of GroningenP.O.Box 1969700 AG GroningenThe Netherlands Bordeaux INP Univ.BordeauxCNRSUMR 5255Site ENSCBP33607 PessacFrance Department of Chemistry South Ural State UniversityChelyabinsk 454080Russian Federation

In ion-annihilation electrochemiluminescence(ECL),luminophore ions are generated by oxidation as well as reduction at electrodes surfaces,and subsequently recombine into an electronically excited state,which emits light.The intensity of the emitted light is often limited by the kinetic rate of recombination of the luminophore ion species.Recombination or annihilation rates are high ranging up to approximately 10^(10) M^(−1) s^(−1) and can be difficult to determine using scanning electrochemical microscopy or high-frequency oscillations of an electrode potential.Here,we propose determining annihilation kinetics by measuring the relative change of the emitted light intensity as a function of luminophore concentration.Using finite element simulations of annihilation ECL in a geometry of two closely spaced electrodes biased at constant potentials,we show that,with increasing concentrations,luminescence intensity crosses over from a quadratic dependence on concentration to a linear regime-depending on the rate of annihilation.Our numerical results are applicable to scanning electrochemical microscopy as well as nanofluidic electrochemical devices to determine fast ion-annihilation kinetics.

关键词： Electrogenerated chemiluminescence annihilation Mechanisms Ion-annihilation kinetics Redox cycling Nanogap transducer

爱她，我们别无选择——annihilation（湮灭）影评

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初中生必读 2019年第10期 36-37,42页

作者：季海峰不详

(上接第9期)Our bodies and our minds will be fragmented into their smallest parts until no part remains. annihilation.我们的身体和思想都将分解成最小块的部分,直到一块都不剩。湮灭。此主句用的是一般将来时的被动语态。英语... 详细信息

(上接第9期)Our bodies and our minds will be fragmented into their smallest parts until no part remains. annihilation.我们的身体和思想都将分解成最小块的部分,直到一块都不剩。湮灭。此主句用的是一般将来时的被动语态。英语动词有两种语态:主动语态和被动语态。两种语态都有多种时态。

关键词：不定代词情态动词 annihilation 一般将来时

爱她,我们别无选择——annihilation(湮灭)影评

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初中生必读 2019年第9期 35-37页

作者：季海峰不详

影片简介&推荐理由《湮灭》讲述了不明生物入侵地球,用七彩光晕笼罩成'闪晃'区域,并逐步扩展范围。政府多次派探险队进入'闪晃'区域寻查真相;但是,踏入'闪晃'区域的人,不是集体自杀,就是自相残杀。

关键词：间接宾语系动词 annihilation 简单句双宾语结构