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Optimization of the imaginary time step evolution for the Dirac equation

Science China(Physics,Mechanics & Astronomy) 2011年第2期54卷 231-235页

作者： LI FangQiong1,ZHANG Ying2,LIANG HaoZhao2,3.& MENG Jie4,2,5 1Guizhou university for Nationalities,Guiyang 550025,China 2State Key Lab Nuclear Physics & Technology,School of Physics,Peking university,Beijing 100871,China 3.nstitut de Physique Nucle’aire,IN2P3.CNRS and Universite’ Paris-Sud,F-91406 Orsay Cedex,France 4School of Physics and Nuclear Energy Engineering,Beihang university,Beijing 100191,China {3. of Physics,university of stellenbosch,stellenbosch,south africa 1. Guizhou university for Nationalities Guiyang 550025 China2. State Key Lab Nuclear Physics & Technology School of Physics Peking University Beijing 100871 China3. Institut de Physique Nucléaire IN2P3-CNRS and Université Paris-Sud F-91406 Orsay Cedex France4. School of Physics and Nuclear Energy Engineering Beihang University Beijing 100191 China5. Department of Physics University of Stellenbosch Stellenbosch South Africa

Taking the single neutron levels of 12C in the Fermi sea as examples,the optimization of the imaginary time step(ITS) evolution with the box size and mesh size for the Dirac equation is *** the weakly bound states,in order to reproduce the exact single-particle energies and wave functions,a relatively large box size is *** long as the exact results can be reproduced,the ITS evolution with a smaller box size converges faster,while for both the weakly and deeply bound states,the ITS evolutions are less sensitive to the mesh ***,one can find a parabola relationship between the mesh size and the corresponding critical time step,i.e.,the largest time step to guarantee the convergence,which suggests that the ITS evolution with a larger mesh size allows larger critical time step,and thus can converge faster to the exact *** conclusions are very helpful for optimizing the evolution procedure in the future self-consistent calculations.

关键词： Dirac equation Schrdinger-like equation imaginary time step method convergence

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中共二十届三中全会为非洲发展带来重大机遇

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当代世界 2024年第8期 78-79页

作者： [南非]谭哲理南非哲理中非国际交流智库

2024年7月15—18日,中国共产党第二十届中央委员会第三次全体会议召开,审议通过了《中共中央关于进一步全面深化改革、推进中国式现代化的决定》(下称《决定》)。中共中央总书记习近平作了重要讲话。作为平等伙伴关系下的朋友和兄弟,非... 详细信息

2024年7月15—18日,中国共产党第二十届中央委员会第三次全体会议召开,审议通过了《中共中央关于进一步全面深化改革、推进中国式现代化的决定》(下称《决定》)。中共中央总书记习近平作了重要讲话。作为平等伙伴关系下的朋友和兄弟,非洲国家认识到,中共二十届三中全会及其决定不仅对中国意义重大,也为非中合作带来更多机遇。

关键词：中国式现代化中共中央总书记全面深化改革三中全会重大机遇《决定》中央委员会习近平

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Convergence for Imaginary Time Step evolution in the Fermi and Dirac seas

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Science China(Physics,Mechanics & Astronomy) 2010年第2期53卷 327-330页

作者： LI FangQiong1,ZHANG Ying2 & MENG Jie2,3.4 1Guizhou university for Nationalities,Guiyang 550025,China 2State Key Lab Nucl. Phys. & Tech.,School of Physics,Peking university,Beijing 100871,China 3.chool of Physics and Nuclear Energy Engineering,Beihang university,Beijing 100191,China 4{3. of Physics,university of stellenbosch,stellenbosch,south africa 1. Guizhou university for Nationalities Guiyang 550025 China2. State Key Lab Nucl. Phys. & Tech. School of Physics Peking University Beijing 100871 China3. School of Physics and Nuclear Energy Engineering Beihang University Beijing 100191 China4. Department of Physics University of Stellenbosch Stellenbosch South Africa

The convergence for the Imaginary Time Step (ITS) evolution with time step is investigated by performing the ITS evolution for the Schrdinger-like equation and the charge-conjugate Schrdinger-like equation deduced from Dirac equation for the single proton levels of 12C in both the Fermi and Dirac seas. For the guaranteed convergence of the ITS evolution to the "exact" results,the time step should be smaller than a "critical" time step Δtc for a given single-particle level. The "critical" time step Δtc is more sensitive to the quantum numbers |κ| than to the energy of the single-particle level. For the single-particle levels with the same κ,their "critical" time steps are in the same order. For the single-particle levels with similar energy,a relatively small (large) "critical" time step for larger (smaller) |κ| is needed. These conclusions can be used in the future self-consistent calculation to optimize the evolution procedure.

关键词： Dirac equation Schrdinger-like equation Imaginary Time Step method convergence

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Micromorphology of Surface Crusts in the Knersvlakte,south africa

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Journal of Mountain Science 2009年第2期6卷 189-196页

作者： Sarah-Jane C.Fox Anthony J.Mills Rosa M.Poch department of Soil Science Stellenbosch UniversityStellenbosch South Africa department of Environment and Soil Science University of LleidaRovira Roure 191 Lleida

Soils in the Knersvlakte are particularly prone to crusting and have lower inherent infiltrability than other soils across western southern africa. Micromorphological techniques were used to examine the structure and porosity of soil crusts in the Knersvlakte to ascertain why crusting is so intense in this region. Quantile regression using boundary lines was employed to examine the relationships between infiltrability and soil properties for all samples （n = 67）. This analysis showed that infiltrability is potentially maximal at low water- dispersible ＇clay plus silt＇ content and low silt content （r^2 = 0.72 and 0.64; respectively, n = 67）（Figure 2）. The strength of crusts, pH, EC, clay mineralogy, and water-dispersible clay, silt and ＇clay plus silt＇ content were compared, and a pore analysis using optical microscopy was undertaken on images of six soil thin sections （n = 6）（circular and parallel polarizers）. Pore analysis was further undertaken on five horizontal slices of equal dimensions taken through each soil thin section. The porosity samples with low infiltrability （〈 100 mm·hr^-1, n = 4） had greater crust strength, lower porosity （both total and in the least porous slice） and greater water-dispersible ＇day plus silt＇ and silt content than the porosity samples with high infiltrability （〉 100mm·hr^-1, n = 2）. The porosity samples with low infiltrability showed a trend of lower pH and greater water dispersible clay percentage. Porosity varied within the porosity samples due to the presence of dense clay/silt bands （〈 0.5 mm in width） with relatively few air vesicles. The porosity samples with horizontal slices of low porosity （but large numbers of air vesicles） had low infiltrability, while those without slices of low porosity （and relatively few air vesicles） had high infiltrability. We conclude that the intense crusting and resultant low infiltrability of soils in the Knersvlakte appears to be related to the formation of thin, dense clay/silt bands in the

关键词： Infiltrability optical microscopy porosity air vesicles

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Selected issues at the interface between nuclear physics and astrophysics as well as the standard model

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中国科学：物理学、力学、天文学英文版 2011年第S1期54卷 119-123页

作者： MENG Jie1,2,3. NIU ZhongMing1, LIANG HaoZhao1 & SUN BaoHua2,4 1State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking university, Beijing 100871, China 2School of Physics and Nuclear Energy Engineering, Beihang university, Beijing 100191, China 3.2} of Physics, {3., stellenbosch, south africa 4Justus-Liebig-Universita¨t Giessen, Heinrich-Buff-Ring 14, Giessen 3.3.2, Germany 1. State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing 100871 China 2. School of Physics and Nuclear Energy Engineering Beihang University Beijing 100191 China 3. department of Physics University of Stellenbosch Stellenbosch South Africa 4. Justus-Liebig-Universit?t Giessen Heinrich-Buff-Ring 14 Giessen 35392 Germany

The density functional theory (DFT) with a minimal number of parameters allows a very successful phenomenological description of ground state properties of nuclei all over the periodic table. The recent developments on the application of the covariant density functional theory as well as its extensions by the group in Beijing for a series of interests and hot topics in nuclear astrophysics and nuclear structure are reviewed, including the rapid neutron-capture process, Th/U chronometer, and isospin corrections for superallowed β transitions.

关键词： rapid neutron-capture process nuclear chronometer isospin symmetry-breaking corrections

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Study on the two and three-parameter working stability regions of 3.-TZP suspension

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Science China(Technological Sciences) 2006年第5期49卷 547-568页

作者： CHEN Youqiang1, 2, ZHANG Xinni3. CHEN Sha’ou3.& QI Ping3.1. department of Chemistry, Qingdao university, Qingdao 266071, China 2. department of Chemistry, Tsinghua university, Beijing 100084, China 3. department of Physics, Qingdao university, Qingdao 266071, China 1. department of Chemistry Qingdao University Qingdao 266071 China 2. department of Chemistry Tsinghua University Beijing 100084 China 3. department of Physics Qingdao University Qingdao 266071 China

We determined the variation tendency of viscosity (η) at various solids load- ing (α) for 3.-TZP suspension as a function of dispersant concentration (Cw) using vis- cosity measurement, measured the diameter of particles as a function of Cw in very dilute suspension using light scattering method, and obtained the surface features of the sedi- ment of suspension with different Cw using SEM. We also discussed the influence of the microstructure of adsorbed polymer layers on particles and their interactions in the dis- persing medium on the stability of suspension. Then two different stable states and two different unstable states for 3.-TZP suspension were given. Accordingly, the (Cw, η), (Cw, α), and (α, η) two-parameter, and (Cw, α, η) three-parameter stability maps were con- structed. Based on the DLVO theory calculations, the dispersant concentration, particle distance (r), and interparticle potential energy (VT) maps with various solids loading for 3.-TZP aqueous suspension were also constructed. In (Cw, r) two-parameter coordinate system, the stable motion region map for particles was established. The Cw, α, and VT,max (the highest potential energy) surface of the potential barrier map was obtained through calculation and simulation on the basis of the surfaces of Cw, r, VT maps introduced above. The (Cw, α) two-parameter stability map was then obtained from the Cw, α, VT,max map. The results showed that this theoretical map can qualitatively prove the experimentally obtained results—the existence of different dispersed states of particles in suspension system and the variation tendency of suspension stability with changing each parame- ter—were reasonable.

关键词： 3.-TZP, suspension, stability, DLVO theory, interparticle potential energy.

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Top 10 Influential Events in carbon neutrality and climate change response for 2023

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Frontiers in Energy 2024年第1期18卷 1-3页

作者： Research Institute of Carbon Neutrality of Shanghai Jiao Tong university Research Institute of Carbon Neutrality Shanghai Jiao Tong UniversityShanghai 200240China

In 2023. the global community intensified its efforts towards achieving carbon neutrality and addressing climate change, witnessing several impactful events. Research Institute of Carbon Neutrality, Shanghai Jiao Tong university compiled the Top 10 Events (in chronological order) in the field of global carbon neutrality and climate change response for 2023. to share with readers these significant moments that document the ongoing ambition and collective efforts of human society.

关键词： neutral collective intensified

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新一轮家电“以旧换新”行动方案影响

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日用电器 2024年第3期 1-2页

作者： 1.华创证券 2.光大证券 3.中信期货华创证券光大证券中信期货

国务院印发《推动大规模设备更新和消费品以旧换新行动方案》（以下简称《行动方案》），明确了5方面20项重点任务和实施设备更新、消费品以旧换新、回收循环利用、标准提升四大行动，提出积极开展家电等消费品以旧换新。《行动方案》...

国务院印发《推动大规模设备更新和消费品以旧换新行动方案》（以下简称《行动方案》），明确了5方面20项重点任务和实施设备更新、消费品以旧换新、回收循环利用、标准提升四大行动，提出积极开展家电等消费品以旧换新。《行动方案》家电直接相关内容1.到2027年废旧家电回收量较2023.增长3.%,

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Congruences on ideal nil-extension of completely regular semigroups

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Chinese Science Bulletin 1998年第5期43卷 379-381页

作者： REN Xueming 1, 2 GUO Yuqi 2 and CEN Jiaping (Shum Kar-ping) 3.. department of Mathematics, Xi’an university of Architecture & Technology, Xi’an 710055, China 2. department of Mathematics, Yunnan university, Kunming 650091, China 3. department of department of Mathematics Xi’an University of Architecture & Technology Xi’an China department of Mathematics Yunnan University Kunming China department of Mathematics Chinese University of Hong Kong Hong Kong

Let S be an ideal nil-extension of a completely regular semigroup K by a nil semigroup Q with zero. A concept of admissible congruence pairs (δ,ω) of S is introduced, where δ and ω are a congruence on Q and a congruence on K respectively. It is proved that every congruence on S can be uniquely respresented by an admissible congruence pair (δ,ω) of S. Suppose that ρ K denotes the Rees congruence induced by the ideal K of S. Then it is shown that for any congruence σ on S,a mapping Γ:σ|→(σ Q,σ K) is an order-preserving bijection from the set of all congruences on S onto the set of all admissible congruence pairs of S,where σ K is the restriction of σ to K and σ Q=(σ∨ρ K)/ρ K. Moreover,the lattice of congruences of S is also discussed. As a special case,every congruence on completely Archimedean semigroups S is described by an admissible quarterple of S. The following question is asked: Is the lattice of congruences of the completely Archimedean semigroup a semimodular lattice?

关键词： completely regular semigroups ideal nil-extension congruences.

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Taurine antagonized oxidative stress injury induced by homocysteine in rat vascular smooth muscle cells

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Acta Pharmacologica Sinica 2004年第03期25卷 87-92页

作者： Lin CHANG2,3.Jian-xin XU4,Jing ZHAO5,Yong-zheng PANG2,3.Chao-shu TANG2,3.Yong-fen QI5,6 2Institute of Cardiovascular Diseases,the FirstHospital,Peking university,Beijing 10003. 3.nstitute of Cardiovascular Diseases,Peking university,Beijing 100083.4Instituteof Biophysics,Chinese Academy of Sciences,Beijing 100101 5department of Physiology,Health Science Center,Peking university,Beijing 100083.China Institute of Cardiovascular Diseases the First Hospital Peking University Institute of Cardiovascular Diseases Peking University Institute of Biophysics Chinese Academy of Sciences Beijing 100101 department of Physiology Health Science Center Pe

AIM: To observe protective effects of taurine on reactive oxygen species generation induced by homocysteine in rat vascular smooth muscle cells (VSMC). METHODS: Rat VSMC was incubated with various concentrations of homocysteine and taurine. The lactate dehydrogenase (LDH) activity which released into culture medium was elevated as an indicator for VSMC injury. The reactive oxygen species (ROS) — hydrogen peroxide (H2O2) and superoxide anion (O2ˉ· )were measured with luminol or lucigenin chemiluminescences method, and the mitochondria Mn-superoxide dismutase (Mn-SOD) and catalase (CAT) were also measured in treated VSMC. RESULTS: LDH leakage from cultured VSMC treated with homocystenie, was increased (P5, 10, and 20 mmol/L) significantly antago- nized 0.5 mmol/L homocysteine-induced H2O2generation in VSMC in a concentration dependent manner (P0.05 vs control). In this study, the superoxide anion in VSMC was not detectable by chemiluminent method. In addition, treatment of VSMC with taurine increased mitochondria Mn-SOD and CAT activity in a concentration dependent manner (P5), but homocysteine decreased mitochondria Mn-SOD and CAT activity (P<0.01 vs control). In addition, co-administration of taurine markedly ameliorated homocysteine-induced inhibition of Mn-SOD and CAT activity in VSMC (P<0.01 vs homocysteine alone group). CONCLUSION: Taurine antagonized the effects of homocysteine on ROS generation and anti-oxidant enzyme activities in rat VSMC in vitro.

关键词： homocysteine taurine vascular smooth muscle mitochondria reactive oxygen species

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